From 816284a3d0e27828b5cc35f3cf539b0711939ce3 Mon Sep 17 00:00:00 2001 From: Axel Rasmussen Date: Mon, 8 Aug 2022 10:56:13 -0700 Subject: userfaultfd: update documentation to describe /dev/userfaultfd Explain the different ways to create a new userfaultfd, and how access control works for each way. [axelrasmussen@google.com: improve wording in documentation, per Mike] Link: https://lkml.kernel.org/r/20220819205201.658693-5-axelrasmussen@google.com Link: https://lkml.kernel.org/r/20220808175614.3885028-5-axelrasmussen@google.com Signed-off-by: Axel Rasmussen Acked-by: Peter Xu Reviewed-by: Shuah Khan Cc: Al Viro Cc: Dave Hansen Cc: Dmitry V. Levin Cc: Gleb Fotengauer-Malinovskiy Cc: Hugh Dickins Cc: Jan Kara Cc: Jonathan Corbet Cc: Mel Gorman Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Zhang Yi Cc: Mike Rapoport Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/userfaultfd.rst | 41 ++++++++++++++++++++++++++-- Documentation/admin-guide/sysctl/vm.rst | 3 ++ 2 files changed, 41 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst index 6528036093e1..83f31919ebb3 100644 --- a/Documentation/admin-guide/mm/userfaultfd.rst +++ b/Documentation/admin-guide/mm/userfaultfd.rst @@ -17,7 +17,10 @@ of the ``PROT_NONE+SIGSEGV`` trick. Design ====== -Userfaults are delivered and resolved through the ``userfaultfd`` syscall. +Userspace creates a new userfaultfd, initializes it, and registers one or more +regions of virtual memory with it. Then, any page faults which occur within the +region(s) result in a message being delivered to the userfaultfd, notifying +userspace of the fault. The ``userfaultfd`` (aside from registering and unregistering virtual memory ranges) provides two primary functionalities: @@ -34,12 +37,11 @@ The real advantage of userfaults if compared to regular virtual memory management of mremap/mprotect is that the userfaults in all their operations never involve heavyweight structures like vmas (in fact the ``userfaultfd`` runtime load never takes the mmap_lock for writing). - Vmas are not suitable for page- (or hugepage) granular fault tracking when dealing with virtual address spaces that could span Terabytes. Too many vmas would be needed for that. -The ``userfaultfd`` once opened by invoking the syscall, can also be +The ``userfaultfd``, once created, can also be passed using unix domain sockets to a manager process, so the same manager process could handle the userfaults of a multitude of different processes without them being aware about what is going on @@ -50,6 +52,39 @@ is a corner case that would currently return ``-EBUSY``). API === +Creating a userfaultfd +---------------------- + +There are two ways to create a new userfaultfd, each of which provide ways to +restrict access to this functionality (since historically userfaultfds which +handle kernel page faults have been a useful tool for exploiting the kernel). + +The first way, supported since userfaultfd was introduced, is the +userfaultfd(2) syscall. Access to this is controlled in several ways: + +- Any user can always create a userfaultfd which traps userspace page faults + only. Such a userfaultfd can be created using the userfaultfd(2) syscall + with the flag UFFD_USER_MODE_ONLY. + +- In order to also trap kernel page faults for the address space, either the + process needs the CAP_SYS_PTRACE capability, or the system must have + vm.unprivileged_userfaultfd set to 1. By default, vm.unprivileged_userfaultfd + is set to 0. + +The second way, added to the kernel more recently, is by opening +/dev/userfaultfd and issuing a USERFAULTFD_IOC_NEW ioctl to it. This method +yields equivalent userfaultfds to the userfaultfd(2) syscall. + +Unlike userfaultfd(2), access to /dev/userfaultfd is controlled via normal +filesystem permissions (user/group/mode), which gives fine grained access to +userfaultfd specifically, without also granting other unrelated privileges at +the same time (as e.g. granting CAP_SYS_PTRACE would do). Users who have access +to /dev/userfaultfd can always create userfaultfds that trap kernel page faults; +vm.unprivileged_userfaultfd is not considered. + +Initializing a userfaultfd +-------------------------- + When first opened the ``userfaultfd`` must be enabled invoking the ``UFFDIO_API`` ioctl specifying a ``uffdio_api.api`` value set to ``UFFD_API`` (or a later API version) which will specify the ``read/POLLIN`` protocol diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index 9b833e439f09..988f6a4c8084 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -926,6 +926,9 @@ calls without any restrictions. The default value is 0. +Another way to control permissions for userfaultfd is to use +/dev/userfaultfd instead of userfaultfd(2). See +Documentation/admin-guide/mm/userfaultfd.rst. user_reserve_kbytes =================== -- cgit v1.2.3 From 9a79443ddc3b9c3e1c4766209b86770585b5f7cc Mon Sep 17 00:00:00 2001 From: Charan Teja Kalla Date: Thu, 11 Aug 2022 18:45:29 +0530 Subject: mm/cma_debug: show complete cma name in debugfs directories Currently only 12 characters of the cma name is being used as the debug directories where as the cma name can be of length CMA_MAX_NAME(=64) characters. One side problem with this is having 2 cma's with first common 12 characters would end up in trying to create directories with same name and fails with -EEXIST thus can limit cma debug functionality. The 'cma-' prefix is used initially where cma areas don't have any names and are represented by simple integer values. Since now each cma would be having its own name, drop 'cma-' prefix for the cma debug directories as they are clearly evident that they are for cma debug through creating them in /sys/kernel/debug/cma/ path. Link: https://lkml.kernel.org/r/1660223729-22461-1-git-send-email-quic_charante@quicinc.com Signed-off-by: Charan Teja Kalla Cc: David Hildenbrand Cc: Vlastimil Babka Cc: Pavan Kondeti Cc: Minchan Kim Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/cma_debugfs.rst | 10 +++++----- mm/cma_debug.c | 5 +---- 2 files changed, 6 insertions(+), 9 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/cma_debugfs.rst b/Documentation/admin-guide/mm/cma_debugfs.rst index 4e06ffabd78a..7367e6294ef6 100644 --- a/Documentation/admin-guide/mm/cma_debugfs.rst +++ b/Documentation/admin-guide/mm/cma_debugfs.rst @@ -5,10 +5,10 @@ CMA Debugfs Interface The CMA debugfs interface is useful to retrieve basic information out of the different CMA areas and to test allocation/release in each of the areas. -Each CMA zone represents a directory under /cma/, indexed by the -kernel's CMA index. So the first CMA zone would be: +Each CMA area represents a directory under /cma/, represented by +its CMA name like below: - /cma/cma-0 + /cma/ The structure of the files created under that directory is as follows: @@ -18,8 +18,8 @@ The structure of the files created under that directory is as follows: - [RO] bitmap: The bitmap of page states in the zone. - [WO] alloc: Allocate N pages from that CMA area. For example:: - echo 5 > /cma/cma-2/alloc + echo 5 > /cma//alloc -would try to allocate 5 pages from the cma-2 area. +would try to allocate 5 pages from the 'cma_name' area. - [WO] free: Free N pages from that CMA area, similar to the above. diff --git a/mm/cma_debug.c b/mm/cma_debug.c index c3ffe253e055..602fff89b15f 100644 --- a/mm/cma_debug.c +++ b/mm/cma_debug.c @@ -163,11 +163,8 @@ DEFINE_DEBUGFS_ATTRIBUTE(cma_alloc_fops, NULL, cma_alloc_write, "%llu\n"); static void cma_debugfs_add_one(struct cma *cma, struct dentry *root_dentry) { struct dentry *tmp; - char name[CMA_MAX_NAME]; - scnprintf(name, sizeof(name), "cma-%s", cma->name); - - tmp = debugfs_create_dir(name, root_dentry); + tmp = debugfs_create_dir(cma->name, root_dentry); debugfs_create_file("alloc", 0200, tmp, cma, &cma_alloc_fops); debugfs_create_file("free", 0200, tmp, cma, &cma_free_fops); -- cgit v1.2.3 From c6833e10008f976a173dd5abdf992e492cbc3bcf Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Wed, 13 Jul 2022 16:39:52 +0800 Subject: memory tiering: rate limit NUMA migration throughput In NUMA balancing memory tiering mode, if there are hot pages in slow memory node and cold pages in fast memory node, we need to promote/demote hot/cold pages between the fast and cold memory nodes. A choice is to promote/demote as fast as possible. But the CPU cycles and memory bandwidth consumed by the high promoting/demoting throughput will hurt the latency of some workload because of accessing inflating and slow memory bandwidth contention. A way to resolve this issue is to restrict the max promoting/demoting throughput. It will take longer to finish the promoting/demoting. But the workload latency will be better. This is implemented in this patch as the page promotion rate limit mechanism. The number of the candidate pages to be promoted to the fast memory node via NUMA balancing is counted, if the count exceeds the limit specified by the users, the NUMA balancing promotion will be stopped until the next second. A new sysctl knob kernel.numa_balancing_promote_rate_limit_MBps is added for the users to specify the limit. Link: https://lkml.kernel.org/r/20220713083954.34196-3-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Baolin Wang Tested-by: Baolin Wang Cc: Dave Hansen Cc: Johannes Weiner Cc: Mel Gorman Cc: Michal Hocko Cc: osalvador Cc: Peter Zijlstra Cc: Rik van Riel Cc: Shakeel Butt Cc: Wei Xu Cc: Yang Shi Cc: Zhong Jiang Cc: Zi Yan Signed-off-by: Andrew Morton --- Documentation/admin-guide/sysctl/kernel.rst | 11 ++++++++++ include/linux/mmzone.h | 7 ++++++ include/linux/sched/sysctl.h | 1 + kernel/sched/fair.c | 33 +++++++++++++++++++++++++++-- kernel/sysctl.c | 8 +++++++ mm/vmstat.c | 1 + 6 files changed, 59 insertions(+), 2 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index ee6572b1edad..835c8844bba4 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -635,6 +635,17 @@ different types of memory (represented as different NUMA nodes) to place the hot pages in the fast memory. This is implemented based on unmapping and page fault too. +numa_balancing_promote_rate_limit_MBps +====================================== + +Too high promotion/demotion throughput between different memory types +may hurt application latency. This can be used to rate limit the +promotion throughput. The per-node max promotion throughput in MB/s +will be limited to be no more than the set value. + +A rule of thumb is to set this to less than 1/10 of the PMEM node +write bandwidth. + oops_all_cpu_backtrace ====================== diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 8f571dc7c524..a0003eaa751f 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -221,6 +221,7 @@ enum node_stat_item { #endif #ifdef CONFIG_NUMA_BALANCING PGPROMOTE_SUCCESS, /* promote successfully */ + PGPROMOTE_CANDIDATE, /* candidate pages to promote */ #endif NR_VM_NODE_STAT_ITEMS }; @@ -998,6 +999,12 @@ typedef struct pglist_data { struct deferred_split deferred_split_queue; #endif +#ifdef CONFIG_NUMA_BALANCING + /* start time in ms of current promote rate limit period */ + unsigned int nbp_rl_start; + /* number of promote candidate pages at start time of current rate limit period */ + unsigned long nbp_rl_nr_cand; +#endif /* Fields commonly accessed by the page reclaim scanner */ /* diff --git a/include/linux/sched/sysctl.h b/include/linux/sched/sysctl.h index e650946816d0..303ee7dd0c7e 100644 --- a/include/linux/sched/sysctl.h +++ b/include/linux/sched/sysctl.h @@ -27,6 +27,7 @@ enum sched_tunable_scaling { #ifdef CONFIG_NUMA_BALANCING extern int sysctl_numa_balancing_mode; +extern unsigned int sysctl_numa_balancing_promote_rate_limit; #else #define sysctl_numa_balancing_mode 0 #endif diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 06db566c7660..1d1dd88daaab 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1097,6 +1097,9 @@ unsigned int sysctl_numa_balancing_scan_delay = 1000; /* The page with hint page fault latency < threshold in ms is considered hot */ unsigned int sysctl_numa_balancing_hot_threshold = MSEC_PER_SEC; +/* Restrict the NUMA promotion throughput (MB/s) for each target node. */ +unsigned int sysctl_numa_balancing_promote_rate_limit = 65536; + struct numa_group { refcount_t refcount; @@ -1501,6 +1504,29 @@ static int numa_hint_fault_latency(struct page *page) return (time - last_time) & PAGE_ACCESS_TIME_MASK; } +/* + * For memory tiering mode, too high promotion/demotion throughput may + * hurt application latency. So we provide a mechanism to rate limit + * the number of pages that are tried to be promoted. + */ +static bool numa_promotion_rate_limit(struct pglist_data *pgdat, + unsigned long rate_limit, int nr) +{ + unsigned long nr_cand; + unsigned int now, start; + + now = jiffies_to_msecs(jiffies); + mod_node_page_state(pgdat, PGPROMOTE_CANDIDATE, nr); + nr_cand = node_page_state(pgdat, PGPROMOTE_CANDIDATE); + start = pgdat->nbp_rl_start; + if (now - start > MSEC_PER_SEC && + cmpxchg(&pgdat->nbp_rl_start, start, now) == start) + pgdat->nbp_rl_nr_cand = nr_cand; + if (nr_cand - pgdat->nbp_rl_nr_cand >= rate_limit) + return true; + return false; +} + bool should_numa_migrate_memory(struct task_struct *p, struct page * page, int src_nid, int dst_cpu) { @@ -1515,7 +1541,7 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, if (sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING && !node_is_toptier(src_nid)) { struct pglist_data *pgdat; - unsigned long latency, th; + unsigned long rate_limit, latency, th; pgdat = NODE_DATA(dst_nid); if (pgdat_free_space_enough(pgdat)) @@ -1526,7 +1552,10 @@ bool should_numa_migrate_memory(struct task_struct *p, struct page * page, if (latency >= th) return false; - return true; + rate_limit = sysctl_numa_balancing_promote_rate_limit << \ + (20 - PAGE_SHIFT); + return !numa_promotion_rate_limit(pgdat, rate_limit, + thp_nr_pages(page)); } this_cpupid = cpu_pid_to_cpupid(dst_cpu, current->pid); diff --git a/kernel/sysctl.c b/kernel/sysctl.c index 205d605cacc5..f10a610aa834 100644 --- a/kernel/sysctl.c +++ b/kernel/sysctl.c @@ -1641,6 +1641,14 @@ static struct ctl_table kern_table[] = { .extra1 = SYSCTL_ZERO, .extra2 = SYSCTL_FOUR, }, + { + .procname = "numa_balancing_promote_rate_limit_MBps", + .data = &sysctl_numa_balancing_promote_rate_limit, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = SYSCTL_ZERO, + }, #endif /* CONFIG_NUMA_BALANCING */ { .procname = "panic", diff --git a/mm/vmstat.c b/mm/vmstat.c index 90af9a8572f5..c109167a669c 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -1252,6 +1252,7 @@ const char * const vmstat_text[] = { #endif #ifdef CONFIG_NUMA_BALANCING "pgpromote_success", + "pgpromote_candidate", #endif /* enum writeback_stat_item counters */ -- cgit v1.2.3 From 8f0efa81dfbc6abf86bf410549e61a2636753c86 Mon Sep 17 00:00:00 2001 From: Kassey Li Date: Thu, 18 Aug 2022 10:24:25 +0800 Subject: mm/page_owner.c: add llseek for page_owner It is too slow to dump all the pages, in some usage we just want to dump a given start pfn, for example: a CMA range or a single page. To speed up and save time, this change allows specifying of a start pfn by adding llseek for page_owner. Link: https://lkml.kernel.org/r/20220818022425.31056-1-quic_yingangl@quicinc.com Signed-off-by: Kassey Li Suggested-by: Vlastimil Babka Acked-by: Vlastimil Babka Cc: Joonsoo Kim Cc: Minchan Kim Signed-off-by: Andrew Morton --- Documentation/mm/page_owner.rst | 5 +++++ mm/page_owner.c | 24 +++++++++++++++++++++--- 2 files changed, 26 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/mm/page_owner.rst b/Documentation/mm/page_owner.rst index f5c954afe97c..f18fd8907049 100644 --- a/Documentation/mm/page_owner.rst +++ b/Documentation/mm/page_owner.rst @@ -94,6 +94,11 @@ Usage Page allocated via order XXX, ... PFN XXX ... // Detailed stack + By default, it will do full pfn dump, to start with a given pfn, + page_owner supports fseek. + + FILE *fp = fopen("/sys/kernel/debug/page_owner", "r"); + fseek(fp, pfn_start, SEEK_SET); The ``page_owner_sort`` tool ignores ``PFN`` rows, puts the remaining rows in buf, uses regexp to extract the page order value, counts the times diff --git a/mm/page_owner.c b/mm/page_owner.c index 72839a606e22..90023f938c19 100644 --- a/mm/page_owner.c +++ b/mm/page_owner.c @@ -516,8 +516,10 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) return -EINVAL; page = NULL; - pfn = min_low_pfn + *ppos; - + if (*ppos == 0) + pfn = min_low_pfn; + else + pfn = *ppos; /* Find a valid PFN or the start of a MAX_ORDER_NR_PAGES area */ while (!pfn_valid(pfn) && (pfn & (MAX_ORDER_NR_PAGES - 1)) != 0) pfn++; @@ -588,7 +590,7 @@ read_page_owner(struct file *file, char __user *buf, size_t count, loff_t *ppos) goto ext_put_continue; /* Record the next PFN to read in the file offset */ - *ppos = (pfn - min_low_pfn) + 1; + *ppos = pfn + 1; page_owner_tmp = *page_owner; page_ext_put(page_ext); @@ -601,6 +603,21 @@ ext_put_continue: return 0; } +static loff_t lseek_page_owner(struct file *file, loff_t offset, int orig) +{ + switch (orig) { + case SEEK_SET: + file->f_pos = offset; + break; + case SEEK_CUR: + file->f_pos += offset; + break; + default: + return -EINVAL; + } + return file->f_pos; +} + static void init_pages_in_zone(pg_data_t *pgdat, struct zone *zone) { unsigned long pfn = zone->zone_start_pfn; @@ -693,6 +710,7 @@ static void init_early_allocated_pages(void) static const struct file_operations proc_page_owner_operations = { .read = read_page_owner, + .llseek = lseek_page_owner, }; static int __init pageowner_init(void) -- cgit v1.2.3 From c4f20f1479c456d9dd1c1e6d8bf956a25de742dc Mon Sep 17 00:00:00 2001 From: Li Zhe Date: Thu, 25 Aug 2022 18:27:14 +0800 Subject: page_ext: introduce boot parameter 'early_page_ext' In commit 2f1ee0913ce5 ("Revert "mm: use early_pfn_to_nid in page_ext_init""), we call page_ext_init() after page_alloc_init_late() to avoid some panic problem. It seems that we cannot track early page allocations in current kernel even if page structure has been initialized early. This patch introduces a new boot parameter 'early_page_ext' to resolve this problem. If we pass it to the kernel, page_ext_init() will be moved up and the feature 'deferred initialization of struct pages' will be disabled to initialize the page allocator early and prevent the panic problem above. It can help us to catch early page allocations. This is useful especially when we find that the free memory value is not the same right after different kernel booting. [akpm@linux-foundation.org: fix section issue by removing __meminitdata] Link: https://lkml.kernel.org/r/20220825102714.669-1-lizhe.67@bytedance.com Signed-off-by: Li Zhe Suggested-by: Michal Hocko Acked-by: Michal Hocko Acked-by: Vlastimil Babka Cc: Jason A. Donenfeld Cc: Jonathan Corbet Cc: Kees Cook Cc: Mark-PK Tsai Cc: Masami Hiramatsu (Google) Cc: Steven Rostedt Signed-off-by: Andrew Morton --- Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++ include/linux/page_ext.h | 11 +++++++++++ init/main.c | 6 +++++- mm/page_alloc.c | 2 ++ mm/page_ext.c | 8 ++++++++ 5 files changed, 34 insertions(+), 1 deletion(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 426fa892d311..3b95f65bafe2 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1471,6 +1471,14 @@ Permit 'security.evm' to be updated regardless of current integrity status. + early_page_ext [KNL] Enforces page_ext initialization to earlier + stages so cover more early boot allocations. + Please note that as side effect some optimizations + might be disabled to achieve that (e.g. parallelized + memory initialization is disabled) so the boot process + might take longer, especially on systems with a lot of + memory. Available with CONFIG_PAGE_EXTENSION=y. + failslab= fail_usercopy= fail_page_alloc= diff --git a/include/linux/page_ext.h b/include/linux/page_ext.h index ed27198cdaf4..22be4582faae 100644 --- a/include/linux/page_ext.h +++ b/include/linux/page_ext.h @@ -36,9 +36,15 @@ struct page_ext { unsigned long flags; }; +extern bool early_page_ext; extern unsigned long page_ext_size; extern void pgdat_page_ext_init(struct pglist_data *pgdat); +static inline bool early_page_ext_enabled(void) +{ + return early_page_ext; +} + #ifdef CONFIG_SPARSEMEM static inline void page_ext_init_flatmem(void) { @@ -68,6 +74,11 @@ static inline struct page_ext *page_ext_next(struct page_ext *curr) #else /* !CONFIG_PAGE_EXTENSION */ struct page_ext; +static inline bool early_page_ext_enabled(void) +{ + return false; +} + static inline void pgdat_page_ext_init(struct pglist_data *pgdat) { } diff --git a/init/main.c b/init/main.c index 1fe7942f5d4a..2a475d40f952 100644 --- a/init/main.c +++ b/init/main.c @@ -849,6 +849,9 @@ static void __init mm_init(void) pgtable_init(); debug_objects_mem_init(); vmalloc_init(); + /* Should be run after vmap initialization */ + if (early_page_ext_enabled()) + page_ext_init(); /* Should be run before the first non-init thread is created */ init_espfix_bsp(); /* Should be run after espfix64 is set up. */ @@ -1618,7 +1621,8 @@ static noinline void __init kernel_init_freeable(void) padata_init(); page_alloc_init_late(); /* Initialize page ext after all struct pages are initialized. */ - page_ext_init(); + if (!early_page_ext_enabled()) + page_ext_init(); do_basic_setup(); diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 48c65bf3cb29..1d4278115d71 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -482,6 +482,8 @@ defer_init(int nid, unsigned long pfn, unsigned long end_pfn) { static unsigned long prev_end_pfn, nr_initialised; + if (early_page_ext_enabled()) + return false; /* * prev_end_pfn static that contains the end of previous zone * No need to protect because called very early in boot before smp_init. diff --git a/mm/page_ext.c b/mm/page_ext.c index b236bdd59fa8..affe80243b6d 100644 --- a/mm/page_ext.c +++ b/mm/page_ext.c @@ -91,6 +91,14 @@ unsigned long page_ext_size = sizeof(struct page_ext); static unsigned long total_usage; static struct page_ext *lookup_page_ext(const struct page *page); +bool early_page_ext; +static int __init setup_early_page_ext(char *str) +{ + early_page_ext = true; + return 0; +} +early_param("early_page_ext", setup_early_page_ext); + static bool __init invoke_need_callbacks(void) { int i; -- cgit v1.2.3 From f347c9d2697fcbbb64e077f7113a3887a181b8c0 Mon Sep 17 00:00:00 2001 From: Yang Yang Date: Fri, 5 Aug 2022 03:38:39 +0000 Subject: filemap: make the accounting of thrashing more consistent Once upon a time, we only support accounting thrashing of page cache. Then Joonsoo introduced workingset detection for anonymous pages and we gained the ability to account thrashing of them[1]. So let delayacct account both the thrashing of page cache and anonymous pages, this could make the codes more consistent and simpler. [1] commit aae466b0052e ("mm/swap: implement workingset detection for anonymous LRU") Link: https://lkml.kernel.org/r/20220805033838.1714674-1-yang.yang29@zte.com.cn Signed-off-by: Yang Yang Signed-off-by: CGEL ZTE Acked-by: Joonsoo Kim Cc: Balbir Singh Cc: Jonathan Corbet Cc: Matthew Wilcox (Oracle) Cc: Yang Yang Cc: David Hildenbrand Signed-off-by: Andrew Morton --- Documentation/accounting/delay-accounting.rst | 2 +- mm/filemap.c | 18 ++++-------------- 2 files changed, 5 insertions(+), 15 deletions(-) (limited to 'Documentation') diff --git a/Documentation/accounting/delay-accounting.rst b/Documentation/accounting/delay-accounting.rst index 241d1a87f2cd..7103b62ba6d7 100644 --- a/Documentation/accounting/delay-accounting.rst +++ b/Documentation/accounting/delay-accounting.rst @@ -13,7 +13,7 @@ a) waiting for a CPU (while being runnable) b) completion of synchronous block I/O initiated by the task c) swapping in pages d) memory reclaim -e) thrashing page cache +e) thrashing f) direct compact g) write-protect copy diff --git a/mm/filemap.c b/mm/filemap.c index 8151890e9a00..5570d083ec0f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1221,15 +1221,11 @@ static inline int folio_wait_bit_common(struct folio *folio, int bit_nr, struct wait_page_queue wait_page; wait_queue_entry_t *wait = &wait_page.wait; bool thrashing = false; - bool delayacct = false; unsigned long pflags; if (bit_nr == PG_locked && !folio_test_uptodate(folio) && folio_test_workingset(folio)) { - if (!folio_test_swapbacked(folio)) { - delayacct_thrashing_start(); - delayacct = true; - } + delayacct_thrashing_start(); psi_memstall_enter(&pflags); thrashing = true; } @@ -1329,8 +1325,7 @@ repeat: finish_wait(q, wait); if (thrashing) { - if (delayacct) - delayacct_thrashing_end(); + delayacct_thrashing_end(); psi_memstall_leave(&pflags); } @@ -1378,17 +1373,13 @@ void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep, struct wait_page_queue wait_page; wait_queue_entry_t *wait = &wait_page.wait; bool thrashing = false; - bool delayacct = false; unsigned long pflags; wait_queue_head_t *q; struct folio *folio = page_folio(pfn_swap_entry_to_page(entry)); q = folio_waitqueue(folio); if (!folio_test_uptodate(folio) && folio_test_workingset(folio)) { - if (!folio_test_swapbacked(folio)) { - delayacct_thrashing_start(); - delayacct = true; - } + delayacct_thrashing_start(); psi_memstall_enter(&pflags); thrashing = true; } @@ -1435,8 +1426,7 @@ void migration_entry_wait_on_locked(swp_entry_t entry, pte_t *ptep, finish_wait(q, wait); if (thrashing) { - if (delayacct) - delayacct_thrashing_end(); + delayacct_thrashing_end(); psi_memstall_leave(&pflags); } } -- cgit v1.2.3 From 07017acb06012d250fb68930e809257e6694d324 Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Sun, 18 Sep 2022 02:00:10 -0600 Subject: mm: multi-gen LRU: admin guide MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add an admin guide. Link: https://lkml.kernel.org/r/20220918080010.2920238-14-yuzhao@google.com Signed-off-by: Yu Zhao Acked-by: Brian Geffon Acked-by: Jan Alexander Steffens (heftig) Acked-by: Oleksandr Natalenko Acked-by: Steven Barrett Acked-by: Suleiman Souhlal Acked-by: Mike Rapoport Tested-by: Daniel Byrne Tested-by: Donald Carr Tested-by: Holger Hoffstätte Tested-by: Konstantin Kharlamov Tested-by: Shuang Zhai Tested-by: Sofia Trinh Tested-by: Vaibhav Jain Cc: Andi Kleen Cc: Aneesh Kumar K.V Cc: Barry Song Cc: Catalin Marinas Cc: Dave Hansen Cc: Hillf Danton Cc: Jens Axboe Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Linus Torvalds Cc: Matthew Wilcox Cc: Mel Gorman Cc: Miaohe Lin Cc: Michael Larabel Cc: Michal Hocko Cc: Mike Rapoport Cc: Peter Zijlstra Cc: Qi Zheng Cc: Tejun Heo Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/index.rst | 1 + Documentation/admin-guide/mm/multigen_lru.rst | 162 ++++++++++++++++++++++++++ mm/Kconfig | 3 +- mm/vmscan.c | 4 + 4 files changed, 169 insertions(+), 1 deletion(-) create mode 100644 Documentation/admin-guide/mm/multigen_lru.rst (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/index.rst b/Documentation/admin-guide/mm/index.rst index 1bd11118dfb1..d1064e0ba34a 100644 --- a/Documentation/admin-guide/mm/index.rst +++ b/Documentation/admin-guide/mm/index.rst @@ -32,6 +32,7 @@ the Linux memory management. idle_page_tracking ksm memory-hotplug + multigen_lru nommu-mmap numa_memory_policy numaperf diff --git a/Documentation/admin-guide/mm/multigen_lru.rst b/Documentation/admin-guide/mm/multigen_lru.rst new file mode 100644 index 000000000000..33e068830497 --- /dev/null +++ b/Documentation/admin-guide/mm/multigen_lru.rst @@ -0,0 +1,162 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +Multi-Gen LRU +============= +The multi-gen LRU is an alternative LRU implementation that optimizes +page reclaim and improves performance under memory pressure. Page +reclaim decides the kernel's caching policy and ability to overcommit +memory. It directly impacts the kswapd CPU usage and RAM efficiency. + +Quick start +=========== +Build the kernel with the following configurations. + +* ``CONFIG_LRU_GEN=y`` +* ``CONFIG_LRU_GEN_ENABLED=y`` + +All set! + +Runtime options +=============== +``/sys/kernel/mm/lru_gen/`` contains stable ABIs described in the +following subsections. + +Kill switch +----------- +``enabled`` accepts different values to enable or disable the +following components. Its default value depends on +``CONFIG_LRU_GEN_ENABLED``. All the components should be enabled +unless some of them have unforeseen side effects. Writing to +``enabled`` has no effect when a component is not supported by the +hardware, and valid values will be accepted even when the main switch +is off. + +====== =============================================================== +Values Components +====== =============================================================== +0x0001 The main switch for the multi-gen LRU. +0x0002 Clearing the accessed bit in leaf page table entries in large + batches, when MMU sets it (e.g., on x86). This behavior can + theoretically worsen lock contention (mmap_lock). If it is + disabled, the multi-gen LRU will suffer a minor performance + degradation for workloads that contiguously map hot pages, + whose accessed bits can be otherwise cleared by fewer larger + batches. +0x0004 Clearing the accessed bit in non-leaf page table entries as + well, when MMU sets it (e.g., on x86). This behavior was not + verified on x86 varieties other than Intel and AMD. If it is + disabled, the multi-gen LRU will suffer a negligible + performance degradation. +[yYnN] Apply to all the components above. +====== =============================================================== + +E.g., +:: + + echo y >/sys/kernel/mm/lru_gen/enabled + cat /sys/kernel/mm/lru_gen/enabled + 0x0007 + echo 5 >/sys/kernel/mm/lru_gen/enabled + cat /sys/kernel/mm/lru_gen/enabled + 0x0005 + +Thrashing prevention +-------------------- +Personal computers are more sensitive to thrashing because it can +cause janks (lags when rendering UI) and negatively impact user +experience. The multi-gen LRU offers thrashing prevention to the +majority of laptop and desktop users who do not have ``oomd``. + +Users can write ``N`` to ``min_ttl_ms`` to prevent the working set of +``N`` milliseconds from getting evicted. The OOM killer is triggered +if this working set cannot be kept in memory. In other words, this +option works as an adjustable pressure relief valve, and when open, it +terminates applications that are hopefully not being used. + +Based on the average human detectable lag (~100ms), ``N=1000`` usually +eliminates intolerable janks due to thrashing. Larger values like +``N=3000`` make janks less noticeable at the risk of premature OOM +kills. + +The default value ``0`` means disabled. + +Experimental features +===================== +``/sys/kernel/debug/lru_gen`` accepts commands described in the +following subsections. Multiple command lines are supported, so does +concatenation with delimiters ``,`` and ``;``. + +``/sys/kernel/debug/lru_gen_full`` provides additional stats for +debugging. ``CONFIG_LRU_GEN_STATS=y`` keeps historical stats from +evicted generations in this file. + +Working set estimation +---------------------- +Working set estimation measures how much memory an application needs +in a given time interval, and it is usually done with little impact on +the performance of the application. E.g., data centers want to +optimize job scheduling (bin packing) to improve memory utilizations. +When a new job comes in, the job scheduler needs to find out whether +each server it manages can allocate a certain amount of memory for +this new job before it can pick a candidate. To do so, the job +scheduler needs to estimate the working sets of the existing jobs. + +When it is read, ``lru_gen`` returns a histogram of numbers of pages +accessed over different time intervals for each memcg and node. +``MAX_NR_GENS`` decides the number of bins for each histogram. The +histograms are noncumulative. +:: + + memcg memcg_id memcg_path + node node_id + min_gen_nr age_in_ms nr_anon_pages nr_file_pages + ... + max_gen_nr age_in_ms nr_anon_pages nr_file_pages + +Each bin contains an estimated number of pages that have been accessed +within ``age_in_ms``. E.g., ``min_gen_nr`` contains the coldest pages +and ``max_gen_nr`` contains the hottest pages, since ``age_in_ms`` of +the former is the largest and that of the latter is the smallest. + +Users can write the following command to ``lru_gen`` to create a new +generation ``max_gen_nr+1``: + + ``+ memcg_id node_id max_gen_nr [can_swap [force_scan]]`` + +``can_swap`` defaults to the swap setting and, if it is set to ``1``, +it forces the scan of anon pages when swap is off, and vice versa. +``force_scan`` defaults to ``1`` and, if it is set to ``0``, it +employs heuristics to reduce the overhead, which is likely to reduce +the coverage as well. + +A typical use case is that a job scheduler runs this command at a +certain time interval to create new generations, and it ranks the +servers it manages based on the sizes of their cold pages defined by +this time interval. + +Proactive reclaim +----------------- +Proactive reclaim induces page reclaim when there is no memory +pressure. It usually targets cold pages only. E.g., when a new job +comes in, the job scheduler wants to proactively reclaim cold pages on +the server it selected, to improve the chance of successfully landing +this new job. + +Users can write the following command to ``lru_gen`` to evict +generations less than or equal to ``min_gen_nr``. + + ``- memcg_id node_id min_gen_nr [swappiness [nr_to_reclaim]]`` + +``min_gen_nr`` should be less than ``max_gen_nr-1``, since +``max_gen_nr`` and ``max_gen_nr-1`` are not fully aged (equivalent to +the active list) and therefore cannot be evicted. ``swappiness`` +overrides the default value in ``/proc/sys/vm/swappiness``. +``nr_to_reclaim`` limits the number of pages to evict. + +A typical use case is that a job scheduler runs this command before it +tries to land a new job on a server. If it fails to materialize enough +cold pages because of the overestimation, it retries on the next +server according to the ranking result obtained from the working set +estimation step. This less forceful approach limits the impacts on the +existing jobs. diff --git a/mm/Kconfig b/mm/Kconfig index ab6ef5115eb8..ceec438c0741 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1125,7 +1125,8 @@ config LRU_GEN # make sure folio->flags has enough spare bits depends on 64BIT || !SPARSEMEM || SPARSEMEM_VMEMMAP help - A high performance LRU implementation to overcommit memory. + A high performance LRU implementation to overcommit memory. See + Documentation/admin-guide/mm/multigen_lru.rst for details. config LRU_GEN_ENABLED bool "Enable by default" diff --git a/mm/vmscan.c b/mm/vmscan.c index 0a883b755dbf..1628521b8eda 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -5310,6 +5310,7 @@ static ssize_t show_min_ttl(struct kobject *kobj, struct kobj_attribute *attr, c return sprintf(buf, "%u\n", jiffies_to_msecs(READ_ONCE(lru_gen_min_ttl))); } +/* see Documentation/admin-guide/mm/multigen_lru.rst for details */ static ssize_t store_min_ttl(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t len) { @@ -5343,6 +5344,7 @@ static ssize_t show_enabled(struct kobject *kobj, struct kobj_attribute *attr, c return snprintf(buf, PAGE_SIZE, "0x%04x\n", caps); } +/* see Documentation/admin-guide/mm/multigen_lru.rst for details */ static ssize_t store_enabled(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t len) { @@ -5490,6 +5492,7 @@ static void lru_gen_seq_show_full(struct seq_file *m, struct lruvec *lruvec, seq_putc(m, '\n'); } +/* see Documentation/admin-guide/mm/multigen_lru.rst for details */ static int lru_gen_seq_show(struct seq_file *m, void *v) { unsigned long seq; @@ -5648,6 +5651,7 @@ done: return err; } +/* see Documentation/admin-guide/mm/multigen_lru.rst for details */ static ssize_t lru_gen_seq_write(struct file *file, const char __user *src, size_t len, loff_t *pos) { -- cgit v1.2.3 From 8be976a0937a18118424dd2505925081d9192fd5 Mon Sep 17 00:00:00 2001 From: Yu Zhao Date: Sun, 18 Sep 2022 02:00:11 -0600 Subject: mm: multi-gen LRU: design doc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a design doc. Link: https://lkml.kernel.org/r/20220918080010.2920238-15-yuzhao@google.com Signed-off-by: Yu Zhao Acked-by: Brian Geffon Acked-by: Jan Alexander Steffens (heftig) Acked-by: Oleksandr Natalenko Acked-by: Steven Barrett Acked-by: Suleiman Souhlal Tested-by: Daniel Byrne Tested-by: Donald Carr Tested-by: Holger Hoffstätte Tested-by: Konstantin Kharlamov Tested-by: Shuang Zhai Tested-by: Sofia Trinh Tested-by: Vaibhav Jain Cc: Andi Kleen Cc: Aneesh Kumar K.V Cc: Barry Song Cc: Catalin Marinas Cc: Dave Hansen Cc: Hillf Danton Cc: Jens Axboe Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Linus Torvalds Cc: Matthew Wilcox Cc: Mel Gorman Cc: Miaohe Lin Cc: Michael Larabel Cc: Michal Hocko Cc: Mike Rapoport Cc: Mike Rapoport Cc: Peter Zijlstra Cc: Qi Zheng Cc: Tejun Heo Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- Documentation/mm/index.rst | 1 + Documentation/mm/multigen_lru.rst | 159 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 160 insertions(+) create mode 100644 Documentation/mm/multigen_lru.rst (limited to 'Documentation') diff --git a/Documentation/mm/index.rst b/Documentation/mm/index.rst index 575ccd40e30c..4aa12b8be278 100644 --- a/Documentation/mm/index.rst +++ b/Documentation/mm/index.rst @@ -51,6 +51,7 @@ above structured documentation, or deleted if it has served its purpose. ksm memory-model mmu_notifier + multigen_lru numa overcommit-accounting page_migration diff --git a/Documentation/mm/multigen_lru.rst b/Documentation/mm/multigen_lru.rst new file mode 100644 index 000000000000..d7062c6a8946 --- /dev/null +++ b/Documentation/mm/multigen_lru.rst @@ -0,0 +1,159 @@ +.. SPDX-License-Identifier: GPL-2.0 + +============= +Multi-Gen LRU +============= +The multi-gen LRU is an alternative LRU implementation that optimizes +page reclaim and improves performance under memory pressure. Page +reclaim decides the kernel's caching policy and ability to overcommit +memory. It directly impacts the kswapd CPU usage and RAM efficiency. + +Design overview +=============== +Objectives +---------- +The design objectives are: + +* Good representation of access recency +* Try to profit from spatial locality +* Fast paths to make obvious choices +* Simple self-correcting heuristics + +The representation of access recency is at the core of all LRU +implementations. In the multi-gen LRU, each generation represents a +group of pages with similar access recency. Generations establish a +(time-based) common frame of reference and therefore help make better +choices, e.g., between different memcgs on a computer or different +computers in a data center (for job scheduling). + +Exploiting spatial locality improves efficiency when gathering the +accessed bit. A rmap walk targets a single page and does not try to +profit from discovering a young PTE. A page table walk can sweep all +the young PTEs in an address space, but the address space can be too +sparse to make a profit. The key is to optimize both methods and use +them in combination. + +Fast paths reduce code complexity and runtime overhead. Unmapped pages +do not require TLB flushes; clean pages do not require writeback. +These facts are only helpful when other conditions, e.g., access +recency, are similar. With generations as a common frame of reference, +additional factors stand out. But obvious choices might not be good +choices; thus self-correction is necessary. + +The benefits of simple self-correcting heuristics are self-evident. +Again, with generations as a common frame of reference, this becomes +attainable. Specifically, pages in the same generation can be +categorized based on additional factors, and a feedback loop can +statistically compare the refault percentages across those categories +and infer which of them are better choices. + +Assumptions +----------- +The protection of hot pages and the selection of cold pages are based +on page access channels and patterns. There are two access channels: + +* Accesses through page tables +* Accesses through file descriptors + +The protection of the former channel is by design stronger because: + +1. The uncertainty in determining the access patterns of the former + channel is higher due to the approximation of the accessed bit. +2. The cost of evicting the former channel is higher due to the TLB + flushes required and the likelihood of encountering the dirty bit. +3. The penalty of underprotecting the former channel is higher because + applications usually do not prepare themselves for major page + faults like they do for blocked I/O. E.g., GUI applications + commonly use dedicated I/O threads to avoid blocking rendering + threads. + +There are also two access patterns: + +* Accesses exhibiting temporal locality +* Accesses not exhibiting temporal locality + +For the reasons listed above, the former channel is assumed to follow +the former pattern unless ``VM_SEQ_READ`` or ``VM_RAND_READ`` is +present, and the latter channel is assumed to follow the latter +pattern unless outlying refaults have been observed. + +Workflow overview +================= +Evictable pages are divided into multiple generations for each +``lruvec``. The youngest generation number is stored in +``lrugen->max_seq`` for both anon and file types as they are aged on +an equal footing. The oldest generation numbers are stored in +``lrugen->min_seq[]`` separately for anon and file types as clean file +pages can be evicted regardless of swap constraints. These three +variables are monotonically increasing. + +Generation numbers are truncated into ``order_base_2(MAX_NR_GENS+1)`` +bits in order to fit into the gen counter in ``folio->flags``. Each +truncated generation number is an index to ``lrugen->lists[]``. The +sliding window technique is used to track at least ``MIN_NR_GENS`` and +at most ``MAX_NR_GENS`` generations. The gen counter stores a value +within ``[1, MAX_NR_GENS]`` while a page is on one of +``lrugen->lists[]``; otherwise it stores zero. + +Each generation is divided into multiple tiers. A page accessed ``N`` +times through file descriptors is in tier ``order_base_2(N)``. Unlike +generations, tiers do not have dedicated ``lrugen->lists[]``. In +contrast to moving across generations, which requires the LRU lock, +moving across tiers only involves atomic operations on +``folio->flags`` and therefore has a negligible cost. A feedback loop +modeled after the PID controller monitors refaults over all the tiers +from anon and file types and decides which tiers from which types to +evict or protect. + +There are two conceptually independent procedures: the aging and the +eviction. They form a closed-loop system, i.e., the page reclaim. + +Aging +----- +The aging produces young generations. Given an ``lruvec``, it +increments ``max_seq`` when ``max_seq-min_seq+1`` approaches +``MIN_NR_GENS``. The aging promotes hot pages to the youngest +generation when it finds them accessed through page tables; the +demotion of cold pages happens consequently when it increments +``max_seq``. The aging uses page table walks and rmap walks to find +young PTEs. For the former, it iterates ``lruvec_memcg()->mm_list`` +and calls ``walk_page_range()`` with each ``mm_struct`` on this list +to scan PTEs, and after each iteration, it increments ``max_seq``. For +the latter, when the eviction walks the rmap and finds a young PTE, +the aging scans the adjacent PTEs. For both, on finding a young PTE, +the aging clears the accessed bit and updates the gen counter of the +page mapped by this PTE to ``(max_seq%MAX_NR_GENS)+1``. + +Eviction +-------- +The eviction consumes old generations. Given an ``lruvec``, it +increments ``min_seq`` when ``lrugen->lists[]`` indexed by +``min_seq%MAX_NR_GENS`` becomes empty. To select a type and a tier to +evict from, it first compares ``min_seq[]`` to select the older type. +If both types are equally old, it selects the one whose first tier has +a lower refault percentage. The first tier contains single-use +unmapped clean pages, which are the best bet. The eviction sorts a +page according to its gen counter if the aging has found this page +accessed through page tables and updated its gen counter. It also +moves a page to the next generation, i.e., ``min_seq+1``, if this page +was accessed multiple times through file descriptors and the feedback +loop has detected outlying refaults from the tier this page is in. To +this end, the feedback loop uses the first tier as the baseline, for +the reason stated earlier. + +Summary +------- +The multi-gen LRU can be disassembled into the following parts: + +* Generations +* Rmap walks +* Page table walks +* Bloom filters +* PID controller + +The aging and the eviction form a producer-consumer model; +specifically, the latter drives the former by the sliding window over +generations. Within the aging, rmap walks drive page table walks by +inserting hot densely populated page tables to the Bloom filters. +Within the eviction, the PID controller uses refaults as the feedback +to select types to evict and tiers to protect. -- cgit v1.2.3 From 9832fb87834e2bd925d30020962c81b05948fa7b Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 30 Aug 2022 13:47:36 +0530 Subject: mm/demotion: expose memory tier details via sysfs MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add /sys/devices/virtual/memory_tiering/ where all memory tier related details can be found. All allocated memory tiers will be listed there as /sys/devices/virtual/memory_tiering/memory_tierN/ The nodes which are part of a specific memory tier can be listed via /sys/devices/virtual/memory_tiering/memory_tierN/nodes A directory hierarchy looks like :/sys/devices/virtual/memory_tiering$ tree memory_tier4/ memory_tier4/ ├── nodes ├── subsystem -> ../../../../bus/memory_tiering └── uevent :/sys/devices/virtual/memory_tiering$ cat memory_tier4/nodes 0,2 [aneesh.kumar@linux.ibm.com: drop toptier_nodes from sysfs] Link: https://lkml.kernel.org/r/20220922102201.62168-1-aneesh.kumar@linux.ibm.com Link: https://lkml.kernel.org/r/20220830081736.119281-1-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V Cc: Alistair Popple Cc: Bharata B Rao Cc: Dan Williams Cc: Dave Hansen Cc: Davidlohr Bueso Cc: Hesham Almatary Cc: "Huang, Ying" Cc: Jagdish Gediya Cc: Johannes Weiner Cc: Jonathan Cameron Cc: Michal Hocko Cc: Tim Chen Cc: Wei Xu Cc: Yang Shi Signed-off-by: Andrew Morton --- .../ABI/testing/sysfs-kernel-mm-memory-tiers | 25 +++++ mm/memory-tiers.c | 109 ++++++++++++++++----- 2 files changed, 112 insertions(+), 22 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers (limited to 'Documentation') diff --git a/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers b/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers new file mode 100644 index 000000000000..45985e411f13 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers @@ -0,0 +1,25 @@ +What: /sys/devices/virtual/memory_tiering/ +Date: August 2022 +Contact: Linux memory management mailing list +Description: A collection of all the memory tiers allocated. + + Individual memory tier details are contained in subdirectories + named by the abstract distance of the memory tier. + + /sys/devices/virtual/memory_tiering/memory_tierN/ + + +What: /sys/devices/virtual/memory_tiering/memory_tierN/ + /sys/devices/virtual/memory_tiering/memory_tierN/nodes +Date: August 2022 +Contact: Linux memory management mailing list +Description: Directory with details of a specific memory tier + + This is the directory containing information about a particular + memory tier, memtierN, where N is derived based on abstract distance. + + A smaller value of N implies a higher (faster) memory tier in the + hierarchy. + + nodes: NUMA nodes that are part of this memory tier. + diff --git a/mm/memory-tiers.c b/mm/memory-tiers.c index c82eb0111383..f116b7b6333e 100644 --- a/mm/memory-tiers.c +++ b/mm/memory-tiers.c @@ -19,6 +19,7 @@ struct memory_tier { * adistance_start .. adistance_start + MEMTIER_CHUNK_SIZE */ int adistance_start; + struct device dev; /* All the nodes that are part of all the lower memory tiers. */ nodemask_t lower_tier_mask; }; @@ -36,6 +37,12 @@ static DEFINE_MUTEX(memory_tier_lock); static LIST_HEAD(memory_tiers); static struct node_memory_type_map node_memory_types[MAX_NUMNODES]; static struct memory_dev_type *default_dram_type; + +static struct bus_type memory_tier_subsys = { + .name = "memory_tiering", + .dev_name = "memory_tier", +}; + #ifdef CONFIG_MIGRATION static int top_tier_adistance; /* @@ -98,8 +105,63 @@ static int top_tier_adistance; static struct demotion_nodes *node_demotion __read_mostly; #endif /* CONFIG_MIGRATION */ +static inline struct memory_tier *to_memory_tier(struct device *device) +{ + return container_of(device, struct memory_tier, dev); +} + +static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier *memtier) +{ + nodemask_t nodes = NODE_MASK_NONE; + struct memory_dev_type *memtype; + + list_for_each_entry(memtype, &memtier->memory_types, tier_sibiling) + nodes_or(nodes, nodes, memtype->nodes); + + return nodes; +} + +static void memory_tier_device_release(struct device *dev) +{ + struct memory_tier *tier = to_memory_tier(dev); + /* + * synchronize_rcu in clear_node_memory_tier makes sure + * we don't have rcu access to this memory tier. + */ + kfree(tier); +} + +static ssize_t nodes_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + int ret; + nodemask_t nmask; + + mutex_lock(&memory_tier_lock); + nmask = get_memtier_nodemask(to_memory_tier(dev)); + ret = sysfs_emit(buf, "%*pbl\n", nodemask_pr_args(&nmask)); + mutex_unlock(&memory_tier_lock); + return ret; +} +static DEVICE_ATTR_RO(nodes); + +static struct attribute *memtier_dev_attrs[] = { + &dev_attr_nodes.attr, + NULL +}; + +static const struct attribute_group memtier_dev_group = { + .attrs = memtier_dev_attrs, +}; + +static const struct attribute_group *memtier_dev_groups[] = { + &memtier_dev_group, + NULL +}; + static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memtype) { + int ret; bool found_slot = false; struct memory_tier *memtier, *new_memtier; int adistance = memtype->adistance; @@ -123,15 +185,14 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty list_for_each_entry(memtier, &memory_tiers, list) { if (adistance == memtier->adistance_start) { - list_add(&memtype->tier_sibiling, &memtier->memory_types); - return memtier; + goto link_memtype; } else if (adistance < memtier->adistance_start) { found_slot = true; break; } } - new_memtier = kmalloc(sizeof(struct memory_tier), GFP_KERNEL); + new_memtier = kzalloc(sizeof(struct memory_tier), GFP_KERNEL); if (!new_memtier) return ERR_PTR(-ENOMEM); @@ -142,8 +203,23 @@ static struct memory_tier *find_create_memory_tier(struct memory_dev_type *memty list_add_tail(&new_memtier->list, &memtier->list); else list_add_tail(&new_memtier->list, &memory_tiers); - list_add(&memtype->tier_sibiling, &new_memtier->memory_types); - return new_memtier; + + new_memtier->dev.id = adistance >> MEMTIER_CHUNK_BITS; + new_memtier->dev.bus = &memory_tier_subsys; + new_memtier->dev.release = memory_tier_device_release; + new_memtier->dev.groups = memtier_dev_groups; + + ret = device_register(&new_memtier->dev); + if (ret) { + list_del(&memtier->list); + put_device(&memtier->dev); + return ERR_PTR(ret); + } + memtier = new_memtier; + +link_memtype: + list_add(&memtype->tier_sibiling, &memtier->memory_types); + return memtier; } static struct memory_tier *__node_get_memory_tier(int node) @@ -275,17 +351,6 @@ static void disable_all_demotion_targets(void) synchronize_rcu(); } -static __always_inline nodemask_t get_memtier_nodemask(struct memory_tier *memtier) -{ - nodemask_t nodes = NODE_MASK_NONE; - struct memory_dev_type *memtype; - - list_for_each_entry(memtype, &memtier->memory_types, tier_sibiling) - nodes_or(nodes, nodes, memtype->nodes); - - return nodes; -} - /* * Find an automatic demotion target for all memory * nodes. Failing here is OK. It might just indicate @@ -433,11 +498,7 @@ static struct memory_tier *set_node_memory_tier(int node) static void destroy_memory_tier(struct memory_tier *memtier) { list_del(&memtier->list); - /* - * synchronize_rcu in clear_node_memory_tier makes sure - * we don't have rcu access to this memory tier. - */ - kfree(memtier); + device_unregister(&memtier->dev); } static bool clear_node_memory_tier(int node) @@ -566,9 +627,13 @@ static int __meminit memtier_hotplug_callback(struct notifier_block *self, static int __init memory_tier_init(void) { - int node; + int ret, node; struct memory_tier *memtier; + ret = subsys_virtual_register(&memory_tier_subsys, NULL); + if (ret) + panic("%s() failed to register memory tier subsystem\n", __func__); + #ifdef CONFIG_MIGRATION node_demotion = kcalloc(nr_node_ids, sizeof(struct demotion_nodes), GFP_KERNEL); -- cgit v1.2.3 From 54a611b605901c7d5d05b6b8f5d04a6ceb0962aa Mon Sep 17 00:00:00 2001 From: "Liam R. Howlett" Date: Tue, 6 Sep 2022 19:48:39 +0000 Subject: Maple Tree: add new data structure Patch series "Introducing the Maple Tree" The maple tree is an RCU-safe range based B-tree designed to use modern processor cache efficiently. There are a number of places in the kernel that a non-overlapping range-based tree would be beneficial, especially one with a simple interface. If you use an rbtree with other data structures to improve performance or an interval tree to track non-overlapping ranges, then this is for you. The tree has a branching factor of 10 for non-leaf nodes and 16 for leaf nodes. With the increased branching factor, it is significantly shorter than the rbtree so it has fewer cache misses. The removal of the linked list between subsequent entries also reduces the cache misses and the need to pull in the previous and next VMA during many tree alterations. The first user that is covered in this patch set is the vm_area_struct, where three data structures are replaced by the maple tree: the augmented rbtree, the vma cache, and the linked list of VMAs in the mm_struct. The long term goal is to reduce or remove the mmap_lock contention. The plan is to get to the point where we use the maple tree in RCU mode. Readers will not block for writers. A single write operation will be allowed at a time. A reader re-walks if stale data is encountered. VMAs would be RCU enabled and this mode would be entered once multiple tasks are using the mm_struct. Davidlor said : Yes I like the maple tree, and at this stage I don't think we can ask for : more from this series wrt the MM - albeit there seems to still be some : folks reporting breakage. Fundamentally I see Liam's work to (re)move : complexity out of the MM (not to say that the actual maple tree is not : complex) by consolidating the three complimentary data structures very : much worth it considering performance does not take a hit. This was very : much a turn off with the range locking approach, which worst case scenario : incurred in prohibitive overhead. Also as Liam and Matthew have : mentioned, RCU opens up a lot of nice performance opportunities, and in : addition academia[1] has shown outstanding scalability of address spaces : with the foundation of replacing the locked rbtree with RCU aware trees. A similar work has been discovered in the academic press https://pdos.csail.mit.edu/papers/rcuvm:asplos12.pdf Sheer coincidence. We designed our tree with the intention of solving the hardest problem first. Upon settling on a b-tree variant and a rough outline, we researched ranged based b-trees and RCU b-trees and did find that article. So it was nice to find reassurances that we were on the right path, but our design choice of using ranges made that paper unusable for us. This patch (of 70): The maple tree is an RCU-safe range based B-tree designed to use modern processor cache efficiently. There are a number of places in the kernel that a non-overlapping range-based tree would be beneficial, especially one with a simple interface. If you use an rbtree with other data structures to improve performance or an interval tree to track non-overlapping ranges, then this is for you. The tree has a branching factor of 10 for non-leaf nodes and 16 for leaf nodes. With the increased branching factor, it is significantly shorter than the rbtree so it has fewer cache misses. The removal of the linked list between subsequent entries also reduces the cache misses and the need to pull in the previous and next VMA during many tree alterations. The first user that is covered in this patch set is the vm_area_struct, where three data structures are replaced by the maple tree: the augmented rbtree, the vma cache, and the linked list of VMAs in the mm_struct. The long term goal is to reduce or remove the mmap_lock contention. The plan is to get to the point where we use the maple tree in RCU mode. Readers will not block for writers. A single write operation will be allowed at a time. A reader re-walks if stale data is encountered. VMAs would be RCU enabled and this mode would be entered once multiple tasks are using the mm_struct. There is additional BUG_ON() calls added within the tree, most of which are in debug code. These will be replaced with a WARN_ON() call in the future. There is also additional BUG_ON() calls within the code which will also be reduced in number at a later date. These exist to catch things such as out-of-range accesses which would crash anyways. Link: https://lkml.kernel.org/r/20220906194824.2110408-1-Liam.Howlett@oracle.com Link: https://lkml.kernel.org/r/20220906194824.2110408-2-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett Signed-off-by: Matthew Wilcox (Oracle) Tested-by: David Howells Tested-by: Sven Schnelle Tested-by: Yu Zhao Cc: Vlastimil Babka Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: Catalin Marinas Cc: SeongJae Park Cc: Will Deacon Signed-off-by: Andrew Morton --- Documentation/core-api/index.rst | 1 + Documentation/core-api/maple_tree.rst | 217 + MAINTAINERS | 12 + include/linux/maple_tree.h | 685 ++ include/trace/events/maple_tree.h | 123 + init/main.c | 2 + lib/Kconfig.debug | 15 + lib/Makefile | 2 +- lib/maple_tree.c | 7130 ++++++++++++++++++++ tools/testing/radix-tree/.gitignore | 2 + tools/testing/radix-tree/generated/autoconf.h | 1 + tools/testing/radix-tree/linux/maple_tree.h | 7 + tools/testing/radix-tree/maple.c | 59 + tools/testing/radix-tree/trace/events/maple_tree.h | 5 + 14 files changed, 8260 insertions(+), 1 deletion(-) create mode 100644 Documentation/core-api/maple_tree.rst create mode 100644 include/linux/maple_tree.h create mode 100644 include/trace/events/maple_tree.h create mode 100644 lib/maple_tree.c create mode 100644 tools/testing/radix-tree/linux/maple_tree.h create mode 100644 tools/testing/radix-tree/maple.c create mode 100644 tools/testing/radix-tree/trace/events/maple_tree.h (limited to 'Documentation') diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst index dc95df462eea..1da6a4fac664 100644 --- a/Documentation/core-api/index.rst +++ b/Documentation/core-api/index.rst @@ -36,6 +36,7 @@ Library functionality that is used throughout the kernel. kref assoc_array xarray + maple_tree idr circular-buffers rbtree diff --git a/Documentation/core-api/maple_tree.rst b/Documentation/core-api/maple_tree.rst new file mode 100644 index 000000000000..45defcf15da7 --- /dev/null +++ b/Documentation/core-api/maple_tree.rst @@ -0,0 +1,217 @@ +.. SPDX-License-Identifier: GPL-2.0+ + + +========== +Maple Tree +========== + +:Author: Liam R. Howlett + +Overview +======== + +The Maple Tree is a B-Tree data type which is optimized for storing +non-overlapping ranges, including ranges of size 1. The tree was designed to +be simple to use and does not require a user written search method. It +supports iterating over a range of entries and going to the previous or next +entry in a cache-efficient manner. The tree can also be put into an RCU-safe +mode of operation which allows reading and writing concurrently. Writers must +synchronize on a lock, which can be the default spinlock, or the user can set +the lock to an external lock of a different type. + +The Maple Tree maintains a small memory footprint and was designed to use +modern processor cache efficiently. The majority of the users will be able to +use the normal API. An :ref:`maple-tree-advanced-api` exists for more complex +scenarios. The most important usage of the Maple Tree is the tracking of the +virtual memory areas. + +The Maple Tree can store values between ``0`` and ``ULONG_MAX``. The Maple +Tree reserves values with the bottom two bits set to '10' which are below 4096 +(ie 2, 6, 10 .. 4094) for internal use. If the entries may use reserved +entries then the users can convert the entries using xa_mk_value() and convert +them back by calling xa_to_value(). If the user needs to use a reserved +value, then the user can convert the value when using the +:ref:`maple-tree-advanced-api`, but are blocked by the normal API. + +The Maple Tree can also be configured to support searching for a gap of a given +size (or larger). + +Pre-allocating of nodes is also supported using the +:ref:`maple-tree-advanced-api`. This is useful for users who must guarantee a +successful store operation within a given +code segment when allocating cannot be done. Allocations of nodes are +relatively small at around 256 bytes. + +.. _maple-tree-normal-api: + +Normal API +========== + +Start by initialising a maple tree, either with DEFINE_MTREE() for statically +allocated maple trees or mt_init() for dynamically allocated ones. A +freshly-initialised maple tree contains a ``NULL`` pointer for the range ``0`` +- ``ULONG_MAX``. There are currently two types of maple trees supported: the +allocation tree and the regular tree. The regular tree has a higher branching +factor for internal nodes. The allocation tree has a lower branching factor +but allows the user to search for a gap of a given size or larger from either +``0`` upwards or ``ULONG_MAX`` down. An allocation tree can be used by +passing in the ``MT_FLAGS_ALLOC_RANGE`` flag when initialising the tree. + +You can then set entries using mtree_store() or mtree_store_range(). +mtree_store() will overwrite any entry with the new entry and return 0 on +success or an error code otherwise. mtree_store_range() works in the same way +but takes a range. mtree_load() is used to retrieve the entry stored at a +given index. You can use mtree_erase() to erase an entire range by only +knowing one value within that range, or mtree_store() call with an entry of +NULL may be used to partially erase a range or many ranges at once. + +If you want to only store a new entry to a range (or index) if that range is +currently ``NULL``, you can use mtree_insert_range() or mtree_insert() which +return -EEXIST if the range is not empty. + +You can search for an entry from an index upwards by using mt_find(). + +You can walk each entry within a range by calling mt_for_each(). You must +provide a temporary variable to store a cursor. If you want to walk each +element of the tree then ``0`` and ``ULONG_MAX`` may be used as the range. If +the caller is going to hold the lock for the duration of the walk then it is +worth looking at the mas_for_each() API in the :ref:`maple-tree-advanced-api` +section. + +Sometimes it is necessary to ensure the next call to store to a maple tree does +not allocate memory, please see :ref:`maple-tree-advanced-api` for this use case. + +Finally, you can remove all entries from a maple tree by calling +mtree_destroy(). If the maple tree entries are pointers, you may wish to free +the entries first. + +Allocating Nodes +---------------- + +The allocations are handled by the internal tree code. See +:ref:`maple-tree-advanced-alloc` for other options. + +Locking +------- + +You do not have to worry about locking. See :ref:`maple-tree-advanced-locks` +for other options. + +The Maple Tree uses RCU and an internal spinlock to synchronise access: + +Takes RCU read lock: + * mtree_load() + * mt_find() + * mt_for_each() + * mt_next() + * mt_prev() + +Takes ma_lock internally: + * mtree_store() + * mtree_store_range() + * mtree_insert() + * mtree_insert_range() + * mtree_erase() + * mtree_destroy() + * mt_set_in_rcu() + * mt_clear_in_rcu() + +If you want to take advantage of the internal lock to protect the data +structures that you are storing in the Maple Tree, you can call mtree_lock() +before calling mtree_load(), then take a reference count on the object you +have found before calling mtree_unlock(). This will prevent stores from +removing the object from the tree between looking up the object and +incrementing the refcount. You can also use RCU to avoid dereferencing +freed memory, but an explanation of that is beyond the scope of this +document. + +.. _maple-tree-advanced-api: + +Advanced API +============ + +The advanced API offers more flexibility and better performance at the +cost of an interface which can be harder to use and has fewer safeguards. +You must take care of your own locking while using the advanced API. +You can use the ma_lock, RCU or an external lock for protection. +You can mix advanced and normal operations on the same array, as long +as the locking is compatible. The :ref:`maple-tree-normal-api` is implemented +in terms of the advanced API. + +The advanced API is based around the ma_state, this is where the 'mas' +prefix originates. The ma_state struct keeps track of tree operations to make +life easier for both internal and external tree users. + +Initialising the maple tree is the same as in the :ref:`maple-tree-normal-api`. +Please see above. + +The maple state keeps track of the range start and end in mas->index and +mas->last, respectively. + +mas_walk() will walk the tree to the location of mas->index and set the +mas->index and mas->last according to the range for the entry. + +You can set entries using mas_store(). mas_store() will overwrite any entry +with the new entry and return the first existing entry that is overwritten. +The range is passed in as members of the maple state: index and last. + +You can use mas_erase() to erase an entire range by setting index and +last of the maple state to the desired range to erase. This will erase +the first range that is found in that range, set the maple state index +and last as the range that was erased and return the entry that existed +at that location. + +You can walk each entry within a range by using mas_for_each(). If you want +to walk each element of the tree then ``0`` and ``ULONG_MAX`` may be used as +the range. If the lock needs to be periodically dropped, see the locking +section mas_pause(). + +Using a maple state allows mas_next() and mas_prev() to function as if the +tree was a linked list. With such a high branching factor the amortized +performance penalty is outweighed by cache optimization. mas_next() will +return the next entry which occurs after the entry at index. mas_prev() +will return the previous entry which occurs before the entry at index. + +mas_find() will find the first entry which exists at or above index on +the first call, and the next entry from every subsequent calls. + +mas_find_rev() will find the fist entry which exists at or below the last on +the first call, and the previous entry from every subsequent calls. + +If the user needs to yield the lock during an operation, then the maple state +must be paused using mas_pause(). + +There are a few extra interfaces provided when using an allocation tree. +If you wish to search for a gap within a range, then mas_empty_area() +or mas_empty_area_rev() can be used. mas_empty_area() searches for a gap +starting at the lowest index given up to the maximum of the range. +mas_empty_area_rev() searches for a gap starting at the highest index given +and continues downward to the lower bound of the range. + +.. _maple-tree-advanced-alloc: + +Advanced Allocating Nodes +------------------------- + +Allocations are usually handled internally to the tree, however if allocations +need to occur before a write occurs then calling mas_expected_entries() will +allocate the worst-case number of needed nodes to insert the provided number of +ranges. This also causes the tree to enter mass insertion mode. Once +insertions are complete calling mas_destroy() on the maple state will free the +unused allocations. + +.. _maple-tree-advanced-locks: + +Advanced Locking +---------------- + +The maple tree uses a spinlock by default, but external locks can be used for +tree updates as well. To use an external lock, the tree must be initialized +with the ``MT_FLAGS_LOCK_EXTERN flag``, this is usually done with the +MTREE_INIT_EXT() #define, which takes an external lock as an argument. + +Functions and structures +======================== + +.. kernel-doc:: include/linux/maple_tree.h +.. kernel-doc:: lib/maple_tree.c diff --git a/MAINTAINERS b/MAINTAINERS index 589517372408..c66b63ad83d8 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -12092,6 +12092,18 @@ L: linux-man@vger.kernel.org S: Maintained W: http://www.kernel.org/doc/man-pages +MAPLE TREE +M: Liam R. Howlett +L: linux-mm@kvack.org +S: Supported +F: Documentation/core-api/maple_tree.rst +F: include/linux/maple_tree.h +F: include/trace/events/maple_tree.h +F: lib/maple_tree.c +F: lib/test_maple_tree.c +F: tools/testing/radix-tree/linux/maple_tree.h +F: tools/testing/radix-tree/maple.c + MARDUK (CREATOR CI40) DEVICE TREE SUPPORT M: Rahul Bedarkar L: linux-mips@vger.kernel.org diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h new file mode 100644 index 000000000000..2effab72add1 --- /dev/null +++ b/include/linux/maple_tree.h @@ -0,0 +1,685 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +#ifndef _LINUX_MAPLE_TREE_H +#define _LINUX_MAPLE_TREE_H +/* + * Maple Tree - An RCU-safe adaptive tree for storing ranges + * Copyright (c) 2018-2022 Oracle + * Authors: Liam R. Howlett + * Matthew Wilcox + */ + +#include +#include +#include +/* #define CONFIG_MAPLE_RCU_DISABLED */ +/* #define CONFIG_DEBUG_MAPLE_TREE_VERBOSE */ + +/* + * Allocated nodes are mutable until they have been inserted into the tree, + * at which time they cannot change their type until they have been removed + * from the tree and an RCU grace period has passed. + * + * Removed nodes have their ->parent set to point to themselves. RCU readers + * check ->parent before relying on the value that they loaded from the + * slots array. This lets us reuse the slots array for the RCU head. + * + * Nodes in the tree point to their parent unless bit 0 is set. + */ +#if defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) +/* 64bit sizes */ +#define MAPLE_NODE_SLOTS 31 /* 256 bytes including ->parent */ +#define MAPLE_RANGE64_SLOTS 16 /* 256 bytes */ +#define MAPLE_ARANGE64_SLOTS 10 /* 240 bytes */ +#define MAPLE_ARANGE64_META_MAX 15 /* Out of range for metadata */ +#define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 1) +#else +/* 32bit sizes */ +#define MAPLE_NODE_SLOTS 63 /* 256 bytes including ->parent */ +#define MAPLE_RANGE64_SLOTS 32 /* 256 bytes */ +#define MAPLE_ARANGE64_SLOTS 21 /* 240 bytes */ +#define MAPLE_ARANGE64_META_MAX 31 /* Out of range for metadata */ +#define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 2) +#endif /* defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) */ + +#define MAPLE_NODE_MASK 255UL + +/* + * The node->parent of the root node has bit 0 set and the rest of the pointer + * is a pointer to the tree itself. No more bits are available in this pointer + * (on m68k, the data structure may only be 2-byte aligned). + * + * Internal non-root nodes can only have maple_range_* nodes as parents. The + * parent pointer is 256B aligned like all other tree nodes. When storing a 32 + * or 64 bit values, the offset can fit into 4 bits. The 16 bit values need an + * extra bit to store the offset. This extra bit comes from a reuse of the last + * bit in the node type. This is possible by using bit 1 to indicate if bit 2 + * is part of the type or the slot. + * + * Once the type is decided, the decision of an allocation range type or a range + * type is done by examining the immutable tree flag for the MAPLE_ALLOC_RANGE + * flag. + * + * Node types: + * 0x??1 = Root + * 0x?00 = 16 bit nodes + * 0x010 = 32 bit nodes + * 0x110 = 64 bit nodes + * + * Slot size and location in the parent pointer: + * type : slot location + * 0x??1 : Root + * 0x?00 : 16 bit values, type in 0-1, slot in 2-6 + * 0x010 : 32 bit values, type in 0-2, slot in 3-6 + * 0x110 : 64 bit values, type in 0-2, slot in 3-6 + */ + +/* + * This metadata is used to optimize the gap updating code and in reverse + * searching for gaps or any other code that needs to find the end of the data. + */ +struct maple_metadata { + unsigned char end; + unsigned char gap; +}; + +/* + * Leaf nodes do not store pointers to nodes, they store user data. Users may + * store almost any bit pattern. As noted above, the optimisation of storing an + * entry at 0 in the root pointer cannot be done for data which have the bottom + * two bits set to '10'. We also reserve values with the bottom two bits set to + * '10' which are below 4096 (ie 2, 6, 10 .. 4094) for internal use. Some APIs + * return errnos as a negative errno shifted right by two bits and the bottom + * two bits set to '10', and while choosing to store these values in the array + * is not an error, it may lead to confusion if you're testing for an error with + * mas_is_err(). + * + * Non-leaf nodes store the type of the node pointed to (enum maple_type in bits + * 3-6), bit 2 is reserved. That leaves bits 0-1 unused for now. + * + * In regular B-Tree terms, pivots are called keys. The term pivot is used to + * indicate that the tree is specifying ranges, Pivots may appear in the + * subtree with an entry attached to the value whereas keys are unique to a + * specific position of a B-tree. Pivot values are inclusive of the slot with + * the same index. + */ + +struct maple_range_64 { + struct maple_pnode *parent; + unsigned long pivot[MAPLE_RANGE64_SLOTS - 1]; + union { + void __rcu *slot[MAPLE_RANGE64_SLOTS]; + struct { + void __rcu *pad[MAPLE_RANGE64_SLOTS - 1]; + struct maple_metadata meta; + }; + }; +}; + +/* + * At tree creation time, the user can specify that they're willing to trade off + * storing fewer entries in a tree in return for storing more information in + * each node. + * + * The maple tree supports recording the largest range of NULL entries available + * in this node, also called gaps. This optimises the tree for allocating a + * range. + */ +struct maple_arange_64 { + struct maple_pnode *parent; + unsigned long pivot[MAPLE_ARANGE64_SLOTS - 1]; + void __rcu *slot[MAPLE_ARANGE64_SLOTS]; + unsigned long gap[MAPLE_ARANGE64_SLOTS]; + struct maple_metadata meta; +}; + +struct maple_alloc { + unsigned long total; + unsigned char node_count; + unsigned int request_count; + struct maple_alloc *slot[MAPLE_ALLOC_SLOTS]; +}; + +struct maple_topiary { + struct maple_pnode *parent; + struct maple_enode *next; /* Overlaps the pivot */ +}; + +enum maple_type { + maple_dense, + maple_leaf_64, + maple_range_64, + maple_arange_64, +}; + + +/** + * DOC: Maple tree flags + * + * * MT_FLAGS_ALLOC_RANGE - Track gaps in this tree + * * MT_FLAGS_USE_RCU - Operate in RCU mode + * * MT_FLAGS_HEIGHT_OFFSET - The position of the tree height in the flags + * * MT_FLAGS_HEIGHT_MASK - The mask for the maple tree height value + * * MT_FLAGS_LOCK_MASK - How the mt_lock is used + * * MT_FLAGS_LOCK_IRQ - Acquired irq-safe + * * MT_FLAGS_LOCK_BH - Acquired bh-safe + * * MT_FLAGS_LOCK_EXTERN - mt_lock is not used + * + * MAPLE_HEIGHT_MAX The largest height that can be stored + */ +#define MT_FLAGS_ALLOC_RANGE 0x01 +#define MT_FLAGS_USE_RCU 0x02 +#define MT_FLAGS_HEIGHT_OFFSET 0x02 +#define MT_FLAGS_HEIGHT_MASK 0x7C +#define MT_FLAGS_LOCK_MASK 0x300 +#define MT_FLAGS_LOCK_IRQ 0x100 +#define MT_FLAGS_LOCK_BH 0x200 +#define MT_FLAGS_LOCK_EXTERN 0x300 + +#define MAPLE_HEIGHT_MAX 31 + + +#define MAPLE_NODE_TYPE_MASK 0x0F +#define MAPLE_NODE_TYPE_SHIFT 0x03 + +#define MAPLE_RESERVED_RANGE 4096 + +#ifdef CONFIG_LOCKDEP +typedef struct lockdep_map *lockdep_map_p; +#define mt_lock_is_held(mt) lock_is_held(mt->ma_external_lock) +#define mt_set_external_lock(mt, lock) \ + (mt)->ma_external_lock = &(lock)->dep_map +#else +typedef struct { /* nothing */ } lockdep_map_p; +#define mt_lock_is_held(mt) 1 +#define mt_set_external_lock(mt, lock) do { } while (0) +#endif + +/* + * If the tree contains a single entry at index 0, it is usually stored in + * tree->ma_root. To optimise for the page cache, an entry which ends in '00', + * '01' or '11' is stored in the root, but an entry which ends in '10' will be + * stored in a node. Bits 3-6 are used to store enum maple_type. + * + * The flags are used both to store some immutable information about this tree + * (set at tree creation time) and dynamic information set under the spinlock. + * + * Another use of flags are to indicate global states of the tree. This is the + * case with the MAPLE_USE_RCU flag, which indicates the tree is currently in + * RCU mode. This mode was added to allow the tree to reuse nodes instead of + * re-allocating and RCU freeing nodes when there is a single user. + */ +struct maple_tree { + union { + spinlock_t ma_lock; + lockdep_map_p ma_external_lock; + }; + void __rcu *ma_root; + unsigned int ma_flags; +}; + +/** + * MTREE_INIT() - Initialize a maple tree + * @name: The maple tree name + * @__flags: The maple tree flags + * + */ +#define MTREE_INIT(name, __flags) { \ + .ma_lock = __SPIN_LOCK_UNLOCKED((name).ma_lock), \ + .ma_flags = __flags, \ + .ma_root = NULL, \ +} + +/** + * MTREE_INIT_EXT() - Initialize a maple tree with an external lock. + * @name: The tree name + * @__flags: The maple tree flags + * @__lock: The external lock + */ +#ifdef CONFIG_LOCKDEP +#define MTREE_INIT_EXT(name, __flags, __lock) { \ + .ma_external_lock = &(__lock).dep_map, \ + .ma_flags = (__flags), \ + .ma_root = NULL, \ +} +#else +#define MTREE_INIT_EXT(name, __flags, __lock) MTREE_INIT(name, __flags) +#endif + +#define DEFINE_MTREE(name) \ + struct maple_tree name = MTREE_INIT(name, 0) + +#define mtree_lock(mt) spin_lock((&(mt)->ma_lock)) +#define mtree_unlock(mt) spin_unlock((&(mt)->ma_lock)) + +/* + * The Maple Tree squeezes various bits in at various points which aren't + * necessarily obvious. Usually, this is done by observing that pointers are + * N-byte aligned and thus the bottom log_2(N) bits are available for use. We + * don't use the high bits of pointers to store additional information because + * we don't know what bits are unused on any given architecture. + * + * Nodes are 256 bytes in size and are also aligned to 256 bytes, giving us 8 + * low bits for our own purposes. Nodes are currently of 4 types: + * 1. Single pointer (Range is 0-0) + * 2. Non-leaf Allocation Range nodes + * 3. Non-leaf Range nodes + * 4. Leaf Range nodes All nodes consist of a number of node slots, + * pivots, and a parent pointer. + */ + +struct maple_node { + union { + struct { + struct maple_pnode *parent; + void __rcu *slot[MAPLE_NODE_SLOTS]; + }; + struct { + void *pad; + struct rcu_head rcu; + struct maple_enode *piv_parent; + unsigned char parent_slot; + enum maple_type type; + unsigned char slot_len; + unsigned int ma_flags; + }; + struct maple_range_64 mr64; + struct maple_arange_64 ma64; + struct maple_alloc alloc; + }; +}; + +/* + * More complicated stores can cause two nodes to become one or three and + * potentially alter the height of the tree. Either half of the tree may need + * to be rebalanced against the other. The ma_topiary struct is used to track + * which nodes have been 'cut' from the tree so that the change can be done + * safely at a later date. This is done to support RCU. + */ +struct ma_topiary { + struct maple_enode *head; + struct maple_enode *tail; + struct maple_tree *mtree; +}; + +void *mtree_load(struct maple_tree *mt, unsigned long index); + +int mtree_insert(struct maple_tree *mt, unsigned long index, + void *entry, gfp_t gfp); +int mtree_insert_range(struct maple_tree *mt, unsigned long first, + unsigned long last, void *entry, gfp_t gfp); +int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp, + void *entry, unsigned long size, unsigned long min, + unsigned long max, gfp_t gfp); +int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp, + void *entry, unsigned long size, unsigned long min, + unsigned long max, gfp_t gfp); + +int mtree_store_range(struct maple_tree *mt, unsigned long first, + unsigned long last, void *entry, gfp_t gfp); +int mtree_store(struct maple_tree *mt, unsigned long index, + void *entry, gfp_t gfp); +void *mtree_erase(struct maple_tree *mt, unsigned long index); + +void mtree_destroy(struct maple_tree *mt); +void __mt_destroy(struct maple_tree *mt); + +/** + * mtree_empty() - Determine if a tree has any present entries. + * @mt: Maple Tree. + * + * Context: Any context. + * Return: %true if the tree contains only NULL pointers. + */ +static inline bool mtree_empty(const struct maple_tree *mt) +{ + return mt->ma_root == NULL; +} + +/* Advanced API */ + +/* + * The maple state is defined in the struct ma_state and is used to keep track + * of information during operations, and even between operations when using the + * advanced API. + * + * If state->node has bit 0 set then it references a tree location which is not + * a node (eg the root). If bit 1 is set, the rest of the bits are a negative + * errno. Bit 2 (the 'unallocated slots' bit) is clear. Bits 3-6 indicate the + * node type. + * + * state->alloc either has a request number of nodes or an allocated node. If + * stat->alloc has a requested number of nodes, the first bit will be set (0x1) + * and the remaining bits are the value. If state->alloc is a node, then the + * node will be of type maple_alloc. maple_alloc has MAPLE_NODE_SLOTS - 1 for + * storing more allocated nodes, a total number of nodes allocated, and the + * node_count in this node. node_count is the number of allocated nodes in this + * node. The scaling beyond MAPLE_NODE_SLOTS - 1 is handled by storing further + * nodes into state->alloc->slot[0]'s node. Nodes are taken from state->alloc + * by removing a node from the state->alloc node until state->alloc->node_count + * is 1, when state->alloc is returned and the state->alloc->slot[0] is promoted + * to state->alloc. Nodes are pushed onto state->alloc by putting the current + * state->alloc into the pushed node's slot[0]. + * + * The state also contains the implied min/max of the state->node, the depth of + * this search, and the offset. The implied min/max are either from the parent + * node or are 0-oo for the root node. The depth is incremented or decremented + * every time a node is walked down or up. The offset is the slot/pivot of + * interest in the node - either for reading or writing. + * + * When returning a value the maple state index and last respectively contain + * the start and end of the range for the entry. Ranges are inclusive in the + * Maple Tree. + */ +struct ma_state { + struct maple_tree *tree; /* The tree we're operating in */ + unsigned long index; /* The index we're operating on - range start */ + unsigned long last; /* The last index we're operating on - range end */ + struct maple_enode *node; /* The node containing this entry */ + unsigned long min; /* The minimum index of this node - implied pivot min */ + unsigned long max; /* The maximum index of this node - implied pivot max */ + struct maple_alloc *alloc; /* Allocated nodes for this operation */ + unsigned char depth; /* depth of tree descent during write */ + unsigned char offset; + unsigned char mas_flags; +}; + +struct ma_wr_state { + struct ma_state *mas; + struct maple_node *node; /* Decoded mas->node */ + unsigned long r_min; /* range min */ + unsigned long r_max; /* range max */ + enum maple_type type; /* mas->node type */ + unsigned char offset_end; /* The offset where the write ends */ + unsigned char node_end; /* mas->node end */ + unsigned long *pivots; /* mas->node->pivots pointer */ + unsigned long end_piv; /* The pivot at the offset end */ + void __rcu **slots; /* mas->node->slots pointer */ + void *entry; /* The entry to write */ + void *content; /* The existing entry that is being overwritten */ +}; + +#define mas_lock(mas) spin_lock(&((mas)->tree->ma_lock)) +#define mas_unlock(mas) spin_unlock(&((mas)->tree->ma_lock)) + + +/* + * Special values for ma_state.node. + * MAS_START means we have not searched the tree. + * MAS_ROOT means we have searched the tree and the entry we found lives in + * the root of the tree (ie it has index 0, length 1 and is the only entry in + * the tree). + * MAS_NONE means we have searched the tree and there is no node in the + * tree for this entry. For example, we searched for index 1 in an empty + * tree. Or we have a tree which points to a full leaf node and we + * searched for an entry which is larger than can be contained in that + * leaf node. + * MA_ERROR represents an errno. After dropping the lock and attempting + * to resolve the error, the walk would have to be restarted from the + * top of the tree as the tree may have been modified. + */ +#define MAS_START ((struct maple_enode *)1UL) +#define MAS_ROOT ((struct maple_enode *)5UL) +#define MAS_NONE ((struct maple_enode *)9UL) +#define MAS_PAUSE ((struct maple_enode *)17UL) +#define MA_ERROR(err) \ + ((struct maple_enode *)(((unsigned long)err << 2) | 2UL)) + +#define MA_STATE(name, mt, first, end) \ + struct ma_state name = { \ + .tree = mt, \ + .index = first, \ + .last = end, \ + .node = MAS_START, \ + .min = 0, \ + .max = ULONG_MAX, \ + .alloc = NULL, \ + } + +#define MA_WR_STATE(name, ma_state, wr_entry) \ + struct ma_wr_state name = { \ + .mas = ma_state, \ + .content = NULL, \ + .entry = wr_entry, \ + } + +#define MA_TOPIARY(name, tree) \ + struct ma_topiary name = { \ + .head = NULL, \ + .tail = NULL, \ + .mtree = tree, \ + } + +void *mas_walk(struct ma_state *mas); +void *mas_store(struct ma_state *mas, void *entry); +void *mas_erase(struct ma_state *mas); +int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp); +void mas_store_prealloc(struct ma_state *mas, void *entry); +void *mas_find(struct ma_state *mas, unsigned long max); +void *mas_find_rev(struct ma_state *mas, unsigned long min); +int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp); +bool mas_is_err(struct ma_state *mas); + +bool mas_nomem(struct ma_state *mas, gfp_t gfp); +void mas_pause(struct ma_state *mas); +void maple_tree_init(void); +void mas_destroy(struct ma_state *mas); +int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries); + +void *mas_prev(struct ma_state *mas, unsigned long min); +void *mas_next(struct ma_state *mas, unsigned long max); + +int mas_empty_area(struct ma_state *mas, unsigned long min, unsigned long max, + unsigned long size); + +/* Checks if a mas has not found anything */ +static inline bool mas_is_none(struct ma_state *mas) +{ + return mas->node == MAS_NONE; +} + +/* Checks if a mas has been paused */ +static inline bool mas_is_paused(struct ma_state *mas) +{ + return mas->node == MAS_PAUSE; +} + +void mas_dup_tree(struct ma_state *oldmas, struct ma_state *mas); +void mas_dup_store(struct ma_state *mas, void *entry); + +/* + * This finds an empty area from the highest address to the lowest. + * AKA "Topdown" version, + */ +int mas_empty_area_rev(struct ma_state *mas, unsigned long min, + unsigned long max, unsigned long size); +/** + * mas_reset() - Reset a Maple Tree operation state. + * @mas: Maple Tree operation state. + * + * Resets the error or walk state of the @mas so future walks of the + * array will start from the root. Use this if you have dropped the + * lock and want to reuse the ma_state. + * + * Context: Any context. + */ +static inline void mas_reset(struct ma_state *mas) +{ + mas->node = MAS_START; +} + +/** + * mas_for_each() - Iterate over a range of the maple tree. + * @__mas: Maple Tree operation state (maple_state) + * @__entry: Entry retrieved from the tree + * @__max: maximum index to retrieve from the tree + * + * When returned, mas->index and mas->last will hold the entire range for the + * entry. + * + * Note: may return the zero entry. + * + */ +#define mas_for_each(__mas, __entry, __max) \ + while (((__entry) = mas_find((__mas), (__max))) != NULL) + + +/** + * mas_set_range() - Set up Maple Tree operation state for a different index. + * @mas: Maple Tree operation state. + * @start: New start of range in the Maple Tree. + * @last: New end of range in the Maple Tree. + * + * Move the operation state to refer to a different range. This will + * have the effect of starting a walk from the top; see mas_next() + * to move to an adjacent index. + */ +static inline +void mas_set_range(struct ma_state *mas, unsigned long start, unsigned long last) +{ + mas->index = start; + mas->last = last; + mas->node = MAS_START; +} + +/** + * mas_set() - Set up Maple Tree operation state for a different index. + * @mas: Maple Tree operation state. + * @index: New index into the Maple Tree. + * + * Move the operation state to refer to a different index. This will + * have the effect of starting a walk from the top; see mas_next() + * to move to an adjacent index. + */ +static inline void mas_set(struct ma_state *mas, unsigned long index) +{ + + mas_set_range(mas, index, index); +} + +static inline bool mt_external_lock(const struct maple_tree *mt) +{ + return (mt->ma_flags & MT_FLAGS_LOCK_MASK) == MT_FLAGS_LOCK_EXTERN; +} + +/** + * mt_init_flags() - Initialise an empty maple tree with flags. + * @mt: Maple Tree + * @flags: maple tree flags. + * + * If you need to initialise a Maple Tree with special flags (eg, an + * allocation tree), use this function. + * + * Context: Any context. + */ +static inline void mt_init_flags(struct maple_tree *mt, unsigned int flags) +{ + mt->ma_flags = flags; + if (!mt_external_lock(mt)) + spin_lock_init(&mt->ma_lock); + rcu_assign_pointer(mt->ma_root, NULL); +} + +/** + * mt_init() - Initialise an empty maple tree. + * @mt: Maple Tree + * + * An empty Maple Tree. + * + * Context: Any context. + */ +static inline void mt_init(struct maple_tree *mt) +{ + mt_init_flags(mt, 0); +} + +static inline bool mt_in_rcu(struct maple_tree *mt) +{ +#ifdef CONFIG_MAPLE_RCU_DISABLED + return false; +#endif + return mt->ma_flags & MT_FLAGS_USE_RCU; +} + +/** + * mt_clear_in_rcu() - Switch the tree to non-RCU mode. + * @mt: The Maple Tree + */ +static inline void mt_clear_in_rcu(struct maple_tree *mt) +{ + if (!mt_in_rcu(mt)) + return; + + if (mt_external_lock(mt)) { + BUG_ON(!mt_lock_is_held(mt)); + mt->ma_flags &= ~MT_FLAGS_USE_RCU; + } else { + mtree_lock(mt); + mt->ma_flags &= ~MT_FLAGS_USE_RCU; + mtree_unlock(mt); + } +} + +/** + * mt_set_in_rcu() - Switch the tree to RCU safe mode. + * @mt: The Maple Tree + */ +static inline void mt_set_in_rcu(struct maple_tree *mt) +{ + if (mt_in_rcu(mt)) + return; + + if (mt_external_lock(mt)) { + BUG_ON(!mt_lock_is_held(mt)); + mt->ma_flags |= MT_FLAGS_USE_RCU; + } else { + mtree_lock(mt); + mt->ma_flags |= MT_FLAGS_USE_RCU; + mtree_unlock(mt); + } +} + +void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max); +void *mt_find_after(struct maple_tree *mt, unsigned long *index, + unsigned long max); +void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min); +void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max); + +/** + * mt_for_each - Iterate over each entry starting at index until max. + * @__tree: The Maple Tree + * @__entry: The current entry + * @__index: The index to update to track the location in the tree + * @__max: The maximum limit for @index + * + * Note: Will not return the zero entry. + */ +#define mt_for_each(__tree, __entry, __index, __max) \ + for (__entry = mt_find(__tree, &(__index), __max); \ + __entry; __entry = mt_find_after(__tree, &(__index), __max)) + + +#ifdef CONFIG_DEBUG_MAPLE_TREE +extern atomic_t maple_tree_tests_run; +extern atomic_t maple_tree_tests_passed; + +void mt_dump(const struct maple_tree *mt); +void mt_validate(struct maple_tree *mt); +#define MT_BUG_ON(__tree, __x) do { \ + atomic_inc(&maple_tree_tests_run); \ + if (__x) { \ + pr_info("BUG at %s:%d (%u)\n", \ + __func__, __LINE__, __x); \ + mt_dump(__tree); \ + pr_info("Pass: %u Run:%u\n", \ + atomic_read(&maple_tree_tests_passed), \ + atomic_read(&maple_tree_tests_run)); \ + dump_stack(); \ + } else { \ + atomic_inc(&maple_tree_tests_passed); \ + } \ +} while (0) +#else +#define MT_BUG_ON(__tree, __x) BUG_ON(__x) +#endif /* CONFIG_DEBUG_MAPLE_TREE */ + +#endif /*_LINUX_MAPLE_TREE_H */ diff --git a/include/trace/events/maple_tree.h b/include/trace/events/maple_tree.h new file mode 100644 index 000000000000..2be403bdc2bd --- /dev/null +++ b/include/trace/events/maple_tree.h @@ -0,0 +1,123 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM maple_tree + +#if !defined(_TRACE_MM_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_MM_H + + +#include + +struct ma_state; + +TRACE_EVENT(ma_op, + + TP_PROTO(const char *fn, struct ma_state *mas), + + TP_ARGS(fn, mas), + + TP_STRUCT__entry( + __field(const char *, fn) + __field(unsigned long, min) + __field(unsigned long, max) + __field(unsigned long, index) + __field(unsigned long, last) + __field(void *, node) + ), + + TP_fast_assign( + __entry->fn = fn; + __entry->min = mas->min; + __entry->max = mas->max; + __entry->index = mas->index; + __entry->last = mas->last; + __entry->node = mas->node; + ), + + TP_printk("%s\tNode: %p (%lu %lu) range: %lu-%lu", + __entry->fn, + (void *) __entry->node, + (unsigned long) __entry->min, + (unsigned long) __entry->max, + (unsigned long) __entry->index, + (unsigned long) __entry->last + ) +) +TRACE_EVENT(ma_read, + + TP_PROTO(const char *fn, struct ma_state *mas), + + TP_ARGS(fn, mas), + + TP_STRUCT__entry( + __field(const char *, fn) + __field(unsigned long, min) + __field(unsigned long, max) + __field(unsigned long, index) + __field(unsigned long, last) + __field(void *, node) + ), + + TP_fast_assign( + __entry->fn = fn; + __entry->min = mas->min; + __entry->max = mas->max; + __entry->index = mas->index; + __entry->last = mas->last; + __entry->node = mas->node; + ), + + TP_printk("%s\tNode: %p (%lu %lu) range: %lu-%lu", + __entry->fn, + (void *) __entry->node, + (unsigned long) __entry->min, + (unsigned long) __entry->max, + (unsigned long) __entry->index, + (unsigned long) __entry->last + ) +) + +TRACE_EVENT(ma_write, + + TP_PROTO(const char *fn, struct ma_state *mas, unsigned long piv, + void *val), + + TP_ARGS(fn, mas, piv, val), + + TP_STRUCT__entry( + __field(const char *, fn) + __field(unsigned long, min) + __field(unsigned long, max) + __field(unsigned long, index) + __field(unsigned long, last) + __field(unsigned long, piv) + __field(void *, val) + __field(void *, node) + ), + + TP_fast_assign( + __entry->fn = fn; + __entry->min = mas->min; + __entry->max = mas->max; + __entry->index = mas->index; + __entry->last = mas->last; + __entry->piv = piv; + __entry->val = val; + __entry->node = mas->node; + ), + + TP_printk("%s\tNode %p (%lu %lu) range:%lu-%lu piv (%lu) val %p", + __entry->fn, + (void *) __entry->node, + (unsigned long) __entry->min, + (unsigned long) __entry->max, + (unsigned long) __entry->index, + (unsigned long) __entry->last, + (unsigned long) __entry->piv, + (void *) __entry->val + ) +) +#endif /* _TRACE_MM_H */ + +/* This part must be outside protection */ +#include diff --git a/init/main.c b/init/main.c index 2a475d40f952..eebe0cad4e37 100644 --- a/init/main.c +++ b/init/main.c @@ -117,6 +117,7 @@ static int kernel_init(void *); extern void init_IRQ(void); extern void radix_tree_init(void); +extern void maple_tree_init(void); /* * Debug helper: via this flag we know that we are in 'early bootup code' @@ -1005,6 +1006,7 @@ asmlinkage __visible void __init __no_sanitize_address start_kernel(void) "Interrupts were enabled *very* early, fixing it\n")) local_irq_disable(); radix_tree_init(); + maple_tree_init(); /* * Set up housekeeping before setting up workqueues to allow the unbound diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index bcbe60d6c80c..2becf60995e1 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -820,6 +820,13 @@ config DEBUG_VM_VMACACHE can cause significant overhead, so only enable it in non-production environments. +config DEBUG_VM_MAPLE_TREE + bool "Debug VM maple trees" + depends on DEBUG_VM + select DEBUG_MAPLE_TREE + help + Enable VM maple tree debugging information and extra validations. + If unsure, say N. config DEBUG_VM_RB @@ -1635,6 +1642,14 @@ config BUG_ON_DATA_CORRUPTION If unsure, say N. +config DEBUG_MAPLE_TREE + bool "Debug maple trees" + depends on DEBUG_KERNEL + help + Enable maple tree debugging information and extra validations. + + If unsure, say N. + endmenu config DEBUG_CREDENTIALS diff --git a/lib/Makefile b/lib/Makefile index ffabc30a27d4..6dc0d6f8e57d 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -29,7 +29,7 @@ endif lib-y := ctype.o string.o vsprintf.o cmdline.o \ rbtree.o radix-tree.o timerqueue.o xarray.o \ - idr.o extable.o irq_regs.o argv_split.o \ + maple_tree.o idr.o extable.o irq_regs.o argv_split.o \ flex_proportions.o ratelimit.o show_mem.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ earlycpio.o seq_buf.o siphash.o dec_and_lock.o \ diff --git a/lib/maple_tree.c b/lib/maple_tree.c new file mode 100644 index 000000000000..e1743803c851 --- /dev/null +++ b/lib/maple_tree.c @@ -0,0 +1,7130 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Maple Tree implementation + * Copyright (c) 2018-2022 Oracle Corporation + * Authors: Liam R. Howlett + * Matthew Wilcox + */ + +/* + * DOC: Interesting implementation details of the Maple Tree + * + * Each node type has a number of slots for entries and a number of slots for + * pivots. In the case of dense nodes, the pivots are implied by the position + * and are simply the slot index + the minimum of the node. + * + * In regular B-Tree terms, pivots are called keys. The term pivot is used to + * indicate that the tree is specifying ranges, Pivots may appear in the + * subtree with an entry attached to the value where as keys are unique to a + * specific position of a B-tree. Pivot values are inclusive of the slot with + * the same index. + * + * + * The following illustrates the layout of a range64 nodes slots and pivots. + * + * + * Slots -> | 0 | 1 | 2 | ... | 12 | 13 | 14 | 15 | + * ┬ ┬ ┬ ┬ ┬ ┬ ┬ ┬ ┬ + * │ │ │ │ │ │ │ │ └─ Implied maximum + * │ │ │ │ │ │ │ └─ Pivot 14 + * │ │ │ │ │ │ └─ Pivot 13 + * │ │ │ │ │ └─ Pivot 12 + * │ │ │ │ └─ Pivot 11 + * │ │ │ └─ Pivot 2 + * │ │ └─ Pivot 1 + * │ └─ Pivot 0 + * └─ Implied minimum + * + * Slot contents: + * Internal (non-leaf) nodes contain pointers to other nodes. + * Leaf nodes contain entries. + * + * The location of interest is often referred to as an offset. All offsets have + * a slot, but the last offset has an implied pivot from the node above (or + * UINT_MAX for the root node. + * + * Ranges complicate certain write activities. When modifying any of + * the B-tree variants, it is known that one entry will either be added or + * deleted. When modifying the Maple Tree, one store operation may overwrite + * the entire data set, or one half of the tree, or the middle half of the tree. + * + */ + + +#include +#include +#include +#include +#include +#include +#include + +#define CREATE_TRACE_POINTS +#include + +#define MA_ROOT_PARENT 1 + +/* + * Maple state flags + * * MA_STATE_BULK - Bulk insert mode + * * MA_STATE_REBALANCE - Indicate a rebalance during bulk insert + * * MA_STATE_PREALLOC - Preallocated nodes, WARN_ON allocation + */ +#define MA_STATE_BULK 1 +#define MA_STATE_REBALANCE 2 +#define MA_STATE_PREALLOC 4 + +#define ma_parent_ptr(x) ((struct maple_pnode *)(x)) +#define ma_mnode_ptr(x) ((struct maple_node *)(x)) +#define ma_enode_ptr(x) ((struct maple_enode *)(x)) +static struct kmem_cache *maple_node_cache; + +#ifdef CONFIG_DEBUG_MAPLE_TREE +static const unsigned long mt_max[] = { + [maple_dense] = MAPLE_NODE_SLOTS, + [maple_leaf_64] = ULONG_MAX, + [maple_range_64] = ULONG_MAX, + [maple_arange_64] = ULONG_MAX, +}; +#define mt_node_max(x) mt_max[mte_node_type(x)] +#endif + +static const unsigned char mt_slots[] = { + [maple_dense] = MAPLE_NODE_SLOTS, + [maple_leaf_64] = MAPLE_RANGE64_SLOTS, + [maple_range_64] = MAPLE_RANGE64_SLOTS, + [maple_arange_64] = MAPLE_ARANGE64_SLOTS, +}; +#define mt_slot_count(x) mt_slots[mte_node_type(x)] + +static const unsigned char mt_pivots[] = { + [maple_dense] = 0, + [maple_leaf_64] = MAPLE_RANGE64_SLOTS - 1, + [maple_range_64] = MAPLE_RANGE64_SLOTS - 1, + [maple_arange_64] = MAPLE_ARANGE64_SLOTS - 1, +}; +#define mt_pivot_count(x) mt_pivots[mte_node_type(x)] + +static const unsigned char mt_min_slots[] = { + [maple_dense] = MAPLE_NODE_SLOTS / 2, + [maple_leaf_64] = (MAPLE_RANGE64_SLOTS / 2) - 2, + [maple_range_64] = (MAPLE_RANGE64_SLOTS / 2) - 2, + [maple_arange_64] = (MAPLE_ARANGE64_SLOTS / 2) - 1, +}; +#define mt_min_slot_count(x) mt_min_slots[mte_node_type(x)] + +#define MAPLE_BIG_NODE_SLOTS (MAPLE_RANGE64_SLOTS * 2 + 2) +#define MAPLE_BIG_NODE_GAPS (MAPLE_ARANGE64_SLOTS * 2 + 1) + +struct maple_big_node { + struct maple_pnode *parent; + unsigned long pivot[MAPLE_BIG_NODE_SLOTS - 1]; + union { + struct maple_enode *slot[MAPLE_BIG_NODE_SLOTS]; + struct { + unsigned long padding[MAPLE_BIG_NODE_GAPS]; + unsigned long gap[MAPLE_BIG_NODE_GAPS]; + }; + }; + unsigned char b_end; + enum maple_type type; +}; + +/* + * The maple_subtree_state is used to build a tree to replace a segment of an + * existing tree in a more atomic way. Any walkers of the older tree will hit a + * dead node and restart on updates. + */ +struct maple_subtree_state { + struct ma_state *orig_l; /* Original left side of subtree */ + struct ma_state *orig_r; /* Original right side of subtree */ + struct ma_state *l; /* New left side of subtree */ + struct ma_state *m; /* New middle of subtree (rare) */ + struct ma_state *r; /* New right side of subtree */ + struct ma_topiary *free; /* nodes to be freed */ + struct ma_topiary *destroy; /* Nodes to be destroyed (walked and freed) */ + struct maple_big_node *bn; +}; + +/* Functions */ +static inline struct maple_node *mt_alloc_one(gfp_t gfp) +{ + return kmem_cache_alloc(maple_node_cache, gfp | __GFP_ZERO); +} + +static inline int mt_alloc_bulk(gfp_t gfp, size_t size, void **nodes) +{ + return kmem_cache_alloc_bulk(maple_node_cache, gfp | __GFP_ZERO, size, + nodes); +} + +static inline void mt_free_bulk(size_t size, void __rcu **nodes) +{ + kmem_cache_free_bulk(maple_node_cache, size, (void **)nodes); +} + +static void mt_free_rcu(struct rcu_head *head) +{ + struct maple_node *node = container_of(head, struct maple_node, rcu); + + kmem_cache_free(maple_node_cache, node); +} + +/* + * ma_free_rcu() - Use rcu callback to free a maple node + * @node: The node to free + * + * The maple tree uses the parent pointer to indicate this node is no longer in + * use and will be freed. + */ +static void ma_free_rcu(struct maple_node *node) +{ + node->parent = ma_parent_ptr(node); + call_rcu(&node->rcu, mt_free_rcu); +} + +static unsigned int mt_height(const struct maple_tree *mt) +{ + return (mt->ma_flags & MT_FLAGS_HEIGHT_MASK) >> MT_FLAGS_HEIGHT_OFFSET; +} + +static void mas_set_height(struct ma_state *mas) +{ + unsigned int new_flags = mas->tree->ma_flags; + + new_flags &= ~MT_FLAGS_HEIGHT_MASK; + BUG_ON(mas->depth > MAPLE_HEIGHT_MAX); + new_flags |= mas->depth << MT_FLAGS_HEIGHT_OFFSET; + mas->tree->ma_flags = new_flags; +} + +static unsigned int mas_mt_height(struct ma_state *mas) +{ + return mt_height(mas->tree); +} + +static inline enum maple_type mte_node_type(const struct maple_enode *entry) +{ + return ((unsigned long)entry >> MAPLE_NODE_TYPE_SHIFT) & + MAPLE_NODE_TYPE_MASK; +} + +static inline bool ma_is_dense(const enum maple_type type) +{ + return type < maple_leaf_64; +} + +static inline bool ma_is_leaf(const enum maple_type type) +{ + return type < maple_range_64; +} + +static inline bool mte_is_leaf(const struct maple_enode *entry) +{ + return ma_is_leaf(mte_node_type(entry)); +} + +/* + * We also reserve values with the bottom two bits set to '10' which are + * below 4096 + */ +static inline bool mt_is_reserved(const void *entry) +{ + return ((unsigned long)entry < MAPLE_RESERVED_RANGE) && + xa_is_internal(entry); +} + +static inline void mas_set_err(struct ma_state *mas, long err) +{ + mas->node = MA_ERROR(err); +} + +static inline bool mas_is_ptr(struct ma_state *mas) +{ + return mas->node == MAS_ROOT; +} + +static inline bool mas_is_start(struct ma_state *mas) +{ + return mas->node == MAS_START; +} + +bool mas_is_err(struct ma_state *mas) +{ + return xa_is_err(mas->node); +} + +static inline bool mas_searchable(struct ma_state *mas) +{ + if (mas_is_none(mas)) + return false; + + if (mas_is_ptr(mas)) + return false; + + return true; +} + +static inline struct maple_node *mte_to_node(const struct maple_enode *entry) +{ + return (struct maple_node *)((unsigned long)entry & ~MAPLE_NODE_MASK); +} + +/* + * mte_to_mat() - Convert a maple encoded node to a maple topiary node. + * @entry: The maple encoded node + * + * Return: a maple topiary pointer + */ +static inline struct maple_topiary *mte_to_mat(const struct maple_enode *entry) +{ + return (struct maple_topiary *) + ((unsigned long)entry & ~MAPLE_NODE_MASK); +} + +/* + * mas_mn() - Get the maple state node. + * @mas: The maple state + * + * Return: the maple node (not encoded - bare pointer). + */ +static inline struct maple_node *mas_mn(const struct ma_state *mas) +{ + return mte_to_node(mas->node); +} + +/* + * mte_set_node_dead() - Set a maple encoded node as dead. + * @mn: The maple encoded node. + */ +static inline void mte_set_node_dead(struct maple_enode *mn) +{ + mte_to_node(mn)->parent = ma_parent_ptr(mte_to_node(mn)); + smp_wmb(); /* Needed for RCU */ +} + +/* Bit 1 indicates the root is a node */ +#define MAPLE_ROOT_NODE 0x02 +/* maple_type stored bit 3-6 */ +#define MAPLE_ENODE_TYPE_SHIFT 0x03 +/* Bit 2 means a NULL somewhere below */ +#define MAPLE_ENODE_NULL 0x04 + +static inline struct maple_enode *mt_mk_node(const struct maple_node *node, + enum maple_type type) +{ + return (void *)((unsigned long)node | + (type << MAPLE_ENODE_TYPE_SHIFT) | MAPLE_ENODE_NULL); +} + +static inline void *mte_mk_root(const struct maple_enode *node) +{ + return (void *)((unsigned long)node | MAPLE_ROOT_NODE); +} + +static inline void *mte_safe_root(const struct maple_enode *node) +{ + return (void *)((unsigned long)node & ~MAPLE_ROOT_NODE); +} + +static inline void mte_set_full(const struct maple_enode *node) +{ + node = (void *)((unsigned long)node & ~MAPLE_ENODE_NULL); +} + +static inline void mte_clear_full(const struct maple_enode *node) +{ + node = (void *)((unsigned long)node | MAPLE_ENODE_NULL); +} + +static inline bool ma_is_root(struct maple_node *node) +{ + return ((unsigned long)node->parent & MA_ROOT_PARENT); +} + +static inline bool mte_is_root(const struct maple_enode *node) +{ + return ma_is_root(mte_to_node(node)); +} + +static inline bool mas_is_root_limits(const struct ma_state *mas) +{ + return !mas->min && mas->max == ULONG_MAX; +} + +static inline bool mt_is_alloc(struct maple_tree *mt) +{ + return (mt->ma_flags & MT_FLAGS_ALLOC_RANGE); +} + +/* + * The Parent Pointer + * Excluding root, the parent pointer is 256B aligned like all other tree nodes. + * When storing a 32 or 64 bit values, the offset can fit into 5 bits. The 16 + * bit values need an extra bit to store the offset. This extra bit comes from + * a reuse of the last bit in the node type. This is possible by using bit 1 to + * indicate if bit 2 is part of the type or the slot. + * + * Note types: + * 0x??1 = Root + * 0x?00 = 16 bit nodes + * 0x010 = 32 bit nodes + * 0x110 = 64 bit nodes + * + * Slot size and alignment + * 0b??1 : Root + * 0b?00 : 16 bit values, type in 0-1, slot in 2-7 + * 0b010 : 32 bit values, type in 0-2, slot in 3-7 + * 0b110 : 64 bit values, type in 0-2, slot in 3-7 + */ + +#define MAPLE_PARENT_ROOT 0x01 + +#define MAPLE_PARENT_SLOT_SHIFT 0x03 +#define MAPLE_PARENT_SLOT_MASK 0xF8 + +#define MAPLE_PARENT_16B_SLOT_SHIFT 0x02 +#define MAPLE_PARENT_16B_SLOT_MASK 0xFC + +#define MAPLE_PARENT_RANGE64 0x06 +#define MAPLE_PARENT_RANGE32 0x04 +#define MAPLE_PARENT_NOT_RANGE16 0x02 + +/* + * mte_parent_shift() - Get the parent shift for the slot storage. + * @parent: The parent pointer cast as an unsigned long + * Return: The shift into that pointer to the star to of the slot + */ +static inline unsigned long mte_parent_shift(unsigned long parent) +{ + /* Note bit 1 == 0 means 16B */ + if (likely(parent & MAPLE_PARENT_NOT_RANGE16)) + return MAPLE_PARENT_SLOT_SHIFT; + + return MAPLE_PARENT_16B_SLOT_SHIFT; +} + +/* + * mte_parent_slot_mask() - Get the slot mask for the parent. + * @parent: The parent pointer cast as an unsigned long. + * Return: The slot mask for that parent. + */ +static inline unsigned long mte_parent_slot_mask(unsigned long parent) +{ + /* Note bit 1 == 0 means 16B */ + if (likely(parent & MAPLE_PARENT_NOT_RANGE16)) + return MAPLE_PARENT_SLOT_MASK; + + return MAPLE_PARENT_16B_SLOT_MASK; +} + +/* + * mas_parent_enum() - Return the maple_type of the parent from the stored + * parent type. + * @mas: The maple state + * @node: The maple_enode to extract the parent's enum + * Return: The node->parent maple_type + */ +static inline +enum maple_type mte_parent_enum(struct maple_enode *p_enode, + struct maple_tree *mt) +{ + unsigned long p_type; + + p_type = (unsigned long)p_enode; + if (p_type & MAPLE_PARENT_ROOT) + return 0; /* Validated in the caller. */ + + p_type &= MAPLE_NODE_MASK; + p_type = p_type & ~(MAPLE_PARENT_ROOT | mte_parent_slot_mask(p_type)); + + switch (p_type) { + case MAPLE_PARENT_RANGE64: /* or MAPLE_PARENT_ARANGE64 */ + if (mt_is_alloc(mt)) + return maple_arange_64; + return maple_range_64; + } + + return 0; +} + +static inline +enum maple_type mas_parent_enum(struct ma_state *mas, struct maple_enode *enode) +{ + return mte_parent_enum(ma_enode_ptr(mte_to_node(enode)->parent), mas->tree); +} + +/* + * mte_set_parent() - Set the parent node and encode the slot + * @enode: The encoded maple node. + * @parent: The encoded maple node that is the parent of @enode. + * @slot: The slot that @enode resides in @parent. + * + * Slot number is encoded in the enode->parent bit 3-6 or 2-6, depending on the + * parent type. + */ +static inline +void mte_set_parent(struct maple_enode *enode, const struct maple_enode *parent, + unsigned char slot) +{ + unsigned long val = (unsigned long) parent; + unsigned long shift; + unsigned long type; + enum maple_type p_type = mte_node_type(parent); + + BUG_ON(p_type == maple_dense); + BUG_ON(p_type == maple_leaf_64); + + switch (p_type) { + case maple_range_64: + case maple_arange_64: + shift = MAPLE_PARENT_SLOT_SHIFT; + type = MAPLE_PARENT_RANGE64; + break; + default: + case maple_dense: + case maple_leaf_64: + shift = type = 0; + break; + } + + val &= ~MAPLE_NODE_MASK; /* Clear all node metadata in parent */ + val |= (slot << shift) | type; + mte_to_node(enode)->parent = ma_parent_ptr(val); +} + +/* + * mte_parent_slot() - get the parent slot of @enode. + * @enode: The encoded maple node. + * + * Return: The slot in the parent node where @enode resides. + */ +static inline unsigned int mte_parent_slot(const struct maple_enode *enode) +{ + unsigned long val = (unsigned long) mte_to_node(enode)->parent; + + /* Root. */ + if (val & 1) + return 0; + + /* + * Okay to use MAPLE_PARENT_16B_SLOT_MASK as the last bit will be lost + * by shift if the parent shift is MAPLE_PARENT_SLOT_SHIFT + */ + return (val & MAPLE_PARENT_16B_SLOT_MASK) >> mte_parent_shift(val); +} + +/* + * mte_parent() - Get the parent of @node. + * @node: The encoded maple node. + * + * Return: The parent maple node. + */ +static inline struct maple_node *mte_parent(const struct maple_enode *enode) +{ + return (void *)((unsigned long) + (mte_to_node(enode)->parent) & ~MAPLE_NODE_MASK); +} + +/* + * ma_dead_node() - check if the @enode is dead. + * @enode: The encoded maple node + * + * Return: true if dead, false otherwise. + */ +static inline bool ma_dead_node(const struct maple_node *node) +{ + struct maple_node *parent = (void *)((unsigned long) + node->parent & ~MAPLE_NODE_MASK); + + return (parent == node); +} +/* + * mte_dead_node() - check if the @enode is dead. + * @enode: The encoded maple node + * + * Return: true if dead, false otherwise. + */ +static inline bool mte_dead_node(const struct maple_enode *enode) +{ + struct maple_node *parent, *node; + + node = mte_to_node(enode); + parent = mte_parent(enode); + return (parent == node); +} + +/* + * mas_allocated() - Get the number of nodes allocated in a maple state. + * @mas: The maple state + * + * The ma_state alloc member is overloaded to hold a pointer to the first + * allocated node or to the number of requested nodes to allocate. If bit 0 is + * set, then the alloc contains the number of requested nodes. If there is an + * allocated node, then the total allocated nodes is in that node. + * + * Return: The total number of nodes allocated + */ +static inline unsigned long mas_allocated(const struct ma_state *mas) +{ + if (!mas->alloc || ((unsigned long)mas->alloc & 0x1)) + return 0; + + return mas->alloc->total; +} + +/* + * mas_set_alloc_req() - Set the requested number of allocations. + * @mas: the maple state + * @count: the number of allocations. + * + * The requested number of allocations is either in the first allocated node, + * located in @mas->alloc->request_count, or directly in @mas->alloc if there is + * no allocated node. Set the request either in the node or do the necessary + * encoding to store in @mas->alloc directly. + */ +static inline void mas_set_alloc_req(struct ma_state *mas, unsigned long count) +{ + if (!mas->alloc || ((unsigned long)mas->alloc & 0x1)) { + if (!count) + mas->alloc = NULL; + else + mas->alloc = (struct maple_alloc *)(((count) << 1U) | 1U); + return; + } + + mas->alloc->request_count = count; +} + +/* + * mas_alloc_req() - get the requested number of allocations. + * @mas: The maple state + * + * The alloc count is either stored directly in @mas, or in + * @mas->alloc->request_count if there is at least one node allocated. Decode + * the request count if it's stored directly in @mas->alloc. + * + * Return: The allocation request count. + */ +static inline unsigned int mas_alloc_req(const struct ma_state *mas) +{ + if ((unsigned long)mas->alloc & 0x1) + return (unsigned long)(mas->alloc) >> 1; + else if (mas->alloc) + return mas->alloc->request_count; + return 0; +} + +/* + * ma_pivots() - Get a pointer to the maple node pivots. + * @node - the maple node + * @type - the node type + * + * Return: A pointer to the maple node pivots + */ +static inline unsigned long *ma_pivots(struct maple_node *node, + enum maple_type type) +{ + switch (type) { + case maple_arange_64: + return node->ma64.pivot; + case maple_range_64: + case maple_leaf_64: + return node->mr64.pivot; + case maple_dense: + return NULL; + } + return NULL; +} + +/* + * ma_gaps() - Get a pointer to the maple node gaps. + * @node - the maple node + * @type - the node type + * + * Return: A pointer to the maple node gaps + */ +static inline unsigned long *ma_gaps(struct maple_node *node, + enum maple_type type) +{ + switch (type) { + case maple_arange_64: + return node->ma64.gap; + case maple_range_64: + case maple_leaf_64: + case maple_dense: + return NULL; + } + return NULL; +} + +/* + * mte_pivot() - Get the pivot at @piv of the maple encoded node. + * @mn: The maple encoded node. + * @piv: The pivot. + * + * Return: the pivot at @piv of @mn. + */ +static inline unsigned long mte_pivot(const struct maple_enode *mn, + unsigned char piv) +{ + struct maple_node *node = mte_to_node(mn); + + if (piv >= mt_pivots[piv]) { + WARN_ON(1); + return 0; + } + switch (mte_node_type(mn)) { + case maple_arange_64: + return node->ma64.pivot[piv]; + case maple_range_64: + case maple_leaf_64: + return node->mr64.pivot[piv]; + case maple_dense: + return 0; + } + return 0; +} + +/* + * mas_safe_pivot() - get the pivot at @piv or mas->max. + * @mas: The maple state + * @pivots: The pointer to the maple node pivots + * @piv: The pivot to fetch + * @type: The maple node type + * + * Return: The pivot at @piv within the limit of the @pivots array, @mas->max + * otherwise. + */ +static inline unsigned long +mas_safe_pivot(const struct ma_state *mas, unsigned long *pivots, + unsigned char piv, enum maple_type type) +{ + if (piv >= mt_pivots[type]) + return mas->max; + + return pivots[piv]; +} + +/* + * mas_safe_min() - Return the minimum for a given offset. + * @mas: The maple state + * @pivots: The pointer to the maple node pivots + * @offset: The offset into the pivot array + * + * Return: The minimum range value that is contained in @offset. + */ +static inline unsigned long +mas_safe_min(struct ma_state *mas, unsigned long *pivots, unsigned char offset) +{ + if (likely(offset)) + return pivots[offset - 1] + 1; + + return mas->min; +} + +/* + * mas_logical_pivot() - Get the logical pivot of a given offset. + * @mas: The maple state + * @pivots: The pointer to the maple node pivots + * @offset: The offset into the pivot array + * @type: The maple node type + * + * When there is no value at a pivot (beyond the end of the data), then the + * pivot is actually @mas->max. + * + * Return: the logical pivot of a given @offset. + */ +static inline unsigned long +mas_logical_pivot(struct ma_state *mas, unsigned long *pivots, + unsigned char offset, enum maple_type type) +{ + unsigned long lpiv = mas_safe_pivot(mas, pivots, offset, type); + + if (likely(lpiv)) + return lpiv; + + if (likely(offset)) + return mas->max; + + return lpiv; +} + +/* + * mte_set_pivot() - Set a pivot to a value in an encoded maple node. + * @mn: The encoded maple node + * @piv: The pivot offset + * @val: The value of the pivot + */ +static inline void mte_set_pivot(struct maple_enode *mn, unsigned char piv, + unsigned long val) +{ + struct maple_node *node = mte_to_node(mn); + enum maple_type type = mte_node_type(mn); + + BUG_ON(piv >= mt_pivots[type]); + switch (type) { + default: + case maple_range_64: + case maple_leaf_64: + node->mr64.pivot[piv] = val; + break; + case maple_arange_64: + node->ma64.pivot[piv] = val; + break; + case maple_dense: + break; + } + +} + +/* + * ma_slots() - Get a pointer to the maple node slots. + * @mn: The maple node + * @mt: The maple node type + * + * Return: A pointer to the maple node slots + */ +static inline void __rcu **ma_slots(struct maple_node *mn, enum maple_type mt) +{ + switch (mt) { + default: + case maple_arange_64: + return mn->ma64.slot; + case maple_range_64: + case maple_leaf_64: + return mn->mr64.slot; + case maple_dense: + return mn->slot; + } +} + +static inline bool mt_locked(const struct maple_tree *mt) +{ + return mt_external_lock(mt) ? mt_lock_is_held(mt) : + lockdep_is_held(&mt->ma_lock); +} + +static inline void *mt_slot(const struct maple_tree *mt, + void __rcu **slots, unsigned char offset) +{ + return rcu_dereference_check(slots[offset], mt_locked(mt)); +} + +/* + * mas_slot_locked() - Get the slot value when holding the maple tree lock. + * @mas: The maple state + * @slots: The pointer to the slots + * @offset: The offset into the slots array to fetch + * + * Return: The entry stored in @slots at the @offset. + */ +static inline void *mas_slot_locked(struct ma_state *mas, void __rcu **slots, + unsigned char offset) +{ + return rcu_dereference_protected(slots[offset], mt_locked(mas->tree)); +} + +/* + * mas_slot() - Get the slot value when not holding the maple tree lock. + * @mas: The maple state + * @slots: The pointer to the slots + * @offset: The offset into the slots array to fetch + * + * Return: The entry stored in @slots at the @offset + */ +static inline void *mas_slot(struct ma_state *mas, void __rcu **slots, + unsigned char offset) +{ + return mt_slot(mas->tree, slots, offset); +} + +/* + * mas_root() - Get the maple tree root. + * @mas: The maple state. + * + * Return: The pointer to the root of the tree + */ +static inline void *mas_root(struct ma_state *mas) +{ + return rcu_dereference_check(mas->tree->ma_root, mt_locked(mas->tree)); +} + +static inline void *mt_root_locked(struct maple_tree *mt) +{ + return rcu_dereference_protected(mt->ma_root, mt_locked(mt)); +} + +/* + * mas_root_locked() - Get the maple tree root when holding the maple tree lock. + * @mas: The maple state. + * + * Return: The pointer to the root of the tree + */ +static inline void *mas_root_locked(struct ma_state *mas) +{ + return mt_root_locked(mas->tree); +} + +static inline struct maple_metadata *ma_meta(struct maple_node *mn, + enum maple_type mt) +{ + switch (mt) { + case maple_arange_64: + return &mn->ma64.meta; + default: + return &mn->mr64.meta; + } +} + +/* + * ma_set_meta() - Set the metadata information of a node. + * @mn: The maple node + * @mt: The maple node type + * @offset: The offset of the highest sub-gap in this node. + * @end: The end of the data in this node. + */ +static inline void ma_set_meta(struct maple_node *mn, enum maple_type mt, + unsigned char offset, unsigned char end) +{ + struct maple_metadata *meta = ma_meta(mn, mt); + + meta->gap = offset; + meta->end = end; +} + +/* + * ma_meta_end() - Get the data end of a node from the metadata + * @mn: The maple node + * @mt: The maple node type + */ +static inline unsigned char ma_meta_end(struct maple_node *mn, + enum maple_type mt) +{ + struct maple_metadata *meta = ma_meta(mn, mt); + + return meta->end; +} + +/* + * ma_meta_gap() - Get the largest gap location of a node from the metadata + * @mn: The maple node + * @mt: The maple node type + */ +static inline unsigned char ma_meta_gap(struct maple_node *mn, + enum maple_type mt) +{ + BUG_ON(mt != maple_arange_64); + + return mn->ma64.meta.gap; +} + +/* + * ma_set_meta_gap() - Set the largest gap location in a nodes metadata + * @mn: The maple node + * @mn: The maple node type + * @offset: The location of the largest gap. + */ +static inline void ma_set_meta_gap(struct maple_node *mn, enum maple_type mt, + unsigned char offset) +{ + + struct maple_metadata *meta = ma_meta(mn, mt); + + meta->gap = offset; +} + +/* + * mat_add() - Add a @dead_enode to the ma_topiary of a list of dead nodes. + * @mat - the ma_topiary, a linked list of dead nodes. + * @dead_enode - the node to be marked as dead and added to the tail of the list + * + * Add the @dead_enode to the linked list in @mat. + */ +static inline void mat_add(struct ma_topiary *mat, + struct maple_enode *dead_enode) +{ + mte_set_node_dead(dead_enode); + mte_to_mat(dead_enode)->next = NULL; + if (!mat->tail) { + mat->tail = mat->head = dead_enode; + return; + } + + mte_to_mat(mat->tail)->next = dead_enode; + mat->tail = dead_enode; +} + +static void mte_destroy_walk(struct maple_enode *, struct maple_tree *); +static inline void mas_free(struct ma_state *mas, struct maple_enode *used); + +/* + * mas_mat_free() - Free all nodes in a dead list. + * @mas - the maple state + * @mat - the ma_topiary linked list of dead nodes to free. + * + * Free walk a dead list. + */ +static void mas_mat_free(struct ma_state *mas, struct ma_topiary *mat) +{ + struct maple_enode *next; + + while (mat->head) { + next = mte_to_mat(mat->head)->next; + mas_free(mas, mat->head); + mat->head = next; + } +} + +/* + * mas_mat_destroy() - Free all nodes and subtrees in a dead list. + * @mas - the maple state + * @mat - the ma_topiary linked list of dead nodes to free. + * + * Destroy walk a dead list. + */ +static void mas_mat_destroy(struct ma_state *mas, struct ma_topiary *mat) +{ + struct maple_enode *next; + + while (mat->head) { + next = mte_to_mat(mat->head)->next; + mte_destroy_walk(mat->head, mat->mtree); + mat->head = next; + } +} +/* + * mas_descend() - Descend into the slot stored in the ma_state. + * @mas - the maple state. + * + * Note: Not RCU safe, only use in write side or debug code. + */ +static inline void mas_descend(struct ma_state *mas) +{ + enum maple_type type; + unsigned long *pivots; + struct maple_node *node; + void __rcu **slots; + + node = mas_mn(mas); + type = mte_node_type(mas->node); + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + + if (mas->offset) + mas->min = pivots[mas->offset - 1] + 1; + mas->max = mas_safe_pivot(mas, pivots, mas->offset, type); + mas->node = mas_slot(mas, slots, mas->offset); +} + +/* + * mte_set_gap() - Set a maple node gap. + * @mn: The encoded maple node + * @gap: The offset of the gap to set + * @val: The gap value + */ +static inline void mte_set_gap(const struct maple_enode *mn, + unsigned char gap, unsigned long val) +{ + switch (mte_node_type(mn)) { + default: + break; + case maple_arange_64: + mte_to_node(mn)->ma64.gap[gap] = val; + break; + } +} + +/* + * mas_ascend() - Walk up a level of the tree. + * @mas: The maple state + * + * Sets the @mas->max and @mas->min to the correct values when walking up. This + * may cause several levels of walking up to find the correct min and max. + * May find a dead node which will cause a premature return. + * Return: 1 on dead node, 0 otherwise + */ +static int mas_ascend(struct ma_state *mas) +{ + struct maple_enode *p_enode; /* parent enode. */ + struct maple_enode *a_enode; /* ancestor enode. */ + struct maple_node *a_node; /* ancestor node. */ + struct maple_node *p_node; /* parent node. */ + unsigned char a_slot; + enum maple_type a_type; + unsigned long min, max; + unsigned long *pivots; + unsigned char offset; + bool set_max = false, set_min = false; + + a_node = mas_mn(mas); + if (ma_is_root(a_node)) { + mas->offset = 0; + return 0; + } + + p_node = mte_parent(mas->node); + if (unlikely(a_node == p_node)) + return 1; + a_type = mas_parent_enum(mas, mas->node); + offset = mte_parent_slot(mas->node); + a_enode = mt_mk_node(p_node, a_type); + + /* Check to make sure all parent information is still accurate */ + if (p_node != mte_parent(mas->node)) + return 1; + + mas->node = a_enode; + mas->offset = offset; + + if (mte_is_root(a_enode)) { + mas->max = ULONG_MAX; + mas->min = 0; + return 0; + } + + min = 0; + max = ULONG_MAX; + do { + p_enode = a_enode; + a_type = mas_parent_enum(mas, p_enode); + a_node = mte_parent(p_enode); + a_slot = mte_parent_slot(p_enode); + pivots = ma_pivots(a_node, a_type); + a_enode = mt_mk_node(a_node, a_type); + + if (!set_min && a_slot) { + set_min = true; + min = pivots[a_slot - 1] + 1; + } + + if (!set_max && a_slot < mt_pivots[a_type]) { + set_max = true; + max = pivots[a_slot]; + } + + if (unlikely(ma_dead_node(a_node))) + return 1; + + if (unlikely(ma_is_root(a_node))) + break; + + } while (!set_min || !set_max); + + mas->max = max; + mas->min = min; + return 0; +} + +/* + * mas_pop_node() - Get a previously allocated maple node from the maple state. + * @mas: The maple state + * + * Return: A pointer to a maple node. + */ +static inline struct maple_node *mas_pop_node(struct ma_state *mas) +{ + struct maple_alloc *ret, *node = mas->alloc; + unsigned long total = mas_allocated(mas); + + /* nothing or a request pending. */ + if (unlikely(!total)) + return NULL; + + if (total == 1) { + /* single allocation in this ma_state */ + mas->alloc = NULL; + ret = node; + goto single_node; + } + + if (!node->node_count) { + /* Single allocation in this node. */ + mas->alloc = node->slot[0]; + node->slot[0] = NULL; + mas->alloc->total = node->total - 1; + ret = node; + goto new_head; + } + + node->total--; + ret = node->slot[node->node_count]; + node->slot[node->node_count--] = NULL; + +single_node: +new_head: + ret->total = 0; + ret->node_count = 0; + if (ret->request_count) { + mas_set_alloc_req(mas, ret->request_count + 1); + ret->request_count = 0; + } + return (struct maple_node *)ret; +} + +/* + * mas_push_node() - Push a node back on the maple state allocation. + * @mas: The maple state + * @used: The used maple node + * + * Stores the maple node back into @mas->alloc for reuse. Updates allocated and + * requested node count as necessary. + */ +static inline void mas_push_node(struct ma_state *mas, struct maple_node *used) +{ + struct maple_alloc *reuse = (struct maple_alloc *)used; + struct maple_alloc *head = mas->alloc; + unsigned long count; + unsigned int requested = mas_alloc_req(mas); + + memset(reuse, 0, sizeof(*reuse)); + count = mas_allocated(mas); + + if (count && (head->node_count < MAPLE_ALLOC_SLOTS - 1)) { + if (head->slot[0]) + head->node_count++; + head->slot[head->node_count] = reuse; + head->total++; + goto done; + } + + reuse->total = 1; + if ((head) && !((unsigned long)head & 0x1)) { + head->request_count = 0; + reuse->slot[0] = head; + reuse->total += head->total; + } + + mas->alloc = reuse; +done: + if (requested > 1) + mas_set_alloc_req(mas, requested - 1); +} + +/* + * mas_alloc_nodes() - Allocate nodes into a maple state + * @mas: The maple state + * @gfp: The GFP Flags + */ +static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp) +{ + struct maple_alloc *node; + struct maple_alloc **nodep = &mas->alloc; + unsigned long allocated = mas_allocated(mas); + unsigned long success = allocated; + unsigned int requested = mas_alloc_req(mas); + unsigned int count; + void **slots = NULL; + unsigned int max_req = 0; + + if (!requested) + return; + + mas_set_alloc_req(mas, 0); + if (mas->mas_flags & MA_STATE_PREALLOC) { + if (allocated) + return; + WARN_ON(!allocated); + } + + if (!allocated || mas->alloc->node_count == MAPLE_ALLOC_SLOTS - 1) { + node = (struct maple_alloc *)mt_alloc_one(gfp); + if (!node) + goto nomem_one; + + if (allocated) + node->slot[0] = mas->alloc; + + success++; + mas->alloc = node; + requested--; + } + + node = mas->alloc; + while (requested) { + max_req = MAPLE_ALLOC_SLOTS; + if (node->slot[0]) { + unsigned int offset = node->node_count + 1; + + slots = (void **)&node->slot[offset]; + max_req -= offset; + } else { + slots = (void **)&node->slot; + } + + max_req = min(requested, max_req); + count = mt_alloc_bulk(gfp, max_req, slots); + if (!count) + goto nomem_bulk; + + node->node_count += count; + /* zero indexed. */ + if (slots == (void **)&node->slot) + node->node_count--; + + success += count; + nodep = &node->slot[0]; + node = *nodep; + requested -= count; + } + mas->alloc->total = success; + return; + +nomem_bulk: + /* Clean up potential freed allocations on bulk failure */ + memset(slots, 0, max_req * sizeof(unsigned long)); +nomem_one: + mas_set_alloc_req(mas, requested); + if (mas->alloc && !(((unsigned long)mas->alloc & 0x1))) + mas->alloc->total = success; + mas_set_err(mas, -ENOMEM); + return; + +} + +/* + * mas_free() - Free an encoded maple node + * @mas: The maple state + * @used: The encoded maple node to free. + * + * Uses rcu free if necessary, pushes @used back on the maple state allocations + * otherwise. + */ +static inline void mas_free(struct ma_state *mas, struct maple_enode *used) +{ + struct maple_node *tmp = mte_to_node(used); + + if (mt_in_rcu(mas->tree)) + ma_free_rcu(tmp); + else + mas_push_node(mas, tmp); +} + +/* + * mas_node_count() - Check if enough nodes are allocated and request more if + * there is not enough nodes. + * @mas: The maple state + * @count: The number of nodes needed + * @gfp: the gfp flags + */ +static void mas_node_count_gfp(struct ma_state *mas, int count, gfp_t gfp) +{ + unsigned long allocated = mas_allocated(mas); + + if (allocated < count) { + mas_set_alloc_req(mas, count - allocated); + mas_alloc_nodes(mas, gfp); + } +} + +/* + * mas_node_count() - Check if enough nodes are allocated and request more if + * there is not enough nodes. + * @mas: The maple state + * @count: The number of nodes needed + * + * Note: Uses GFP_NOWAIT | __GFP_NOWARN for gfp flags. + */ +static void mas_node_count(struct ma_state *mas, int count) +{ + return mas_node_count_gfp(mas, count, GFP_NOWAIT | __GFP_NOWARN); +} + +/* + * mas_start() - Sets up maple state for operations. + * @mas: The maple state. + * + * If mas->node == MAS_START, then set the min, max, depth, and offset to + * defaults. + * + * Return: + * - If mas->node is an error or not MAS_START, return NULL. + * - If it's an empty tree: NULL & mas->node == MAS_NONE + * - If it's a single entry: The entry & mas->node == MAS_ROOT + * - If it's a tree: NULL & mas->node == safe root node. + */ +static inline struct maple_enode *mas_start(struct ma_state *mas) +{ + if (likely(mas_is_start(mas))) { + struct maple_enode *root; + + mas->node = MAS_NONE; + mas->min = 0; + mas->max = ULONG_MAX; + mas->depth = 0; + mas->offset = 0; + + root = mas_root(mas); + /* Tree with nodes */ + if (likely(xa_is_node(root))) { + mas->node = mte_safe_root(root); + return NULL; + } + + /* empty tree */ + if (unlikely(!root)) { + mas->offset = MAPLE_NODE_SLOTS; + return NULL; + } + + /* Single entry tree */ + mas->node = MAS_ROOT; + mas->offset = MAPLE_NODE_SLOTS; + + /* Single entry tree. */ + if (mas->index > 0) + return NULL; + + return root; + } + + return NULL; +} + +/* + * ma_data_end() - Find the end of the data in a node. + * @node: The maple node + * @type: The maple node type + * @pivots: The array of pivots in the node + * @max: The maximum value in the node + * + * Uses metadata to find the end of the data when possible. + * Return: The zero indexed last slot with data (may be null). + */ +static inline unsigned char ma_data_end(struct maple_node *node, + enum maple_type type, + unsigned long *pivots, + unsigned long max) +{ + unsigned char offset; + + if (type == maple_arange_64) + return ma_meta_end(node, type); + + offset = mt_pivots[type] - 1; + if (likely(!pivots[offset])) + return ma_meta_end(node, type); + + if (likely(pivots[offset] == max)) + return offset; + + return mt_pivots[type]; +} + +/* + * mas_data_end() - Find the end of the data (slot). + * @mas: the maple state + * + * This method is optimized to check the metadata of a node if the node type + * supports data end metadata. + * + * Return: The zero indexed last slot with data (may be null). + */ +static inline unsigned char mas_data_end(struct ma_state *mas) +{ + enum maple_type type; + struct maple_node *node; + unsigned char offset; + unsigned long *pivots; + + type = mte_node_type(mas->node); + node = mas_mn(mas); + if (type == maple_arange_64) + return ma_meta_end(node, type); + + pivots = ma_pivots(node, type); + offset = mt_pivots[type] - 1; + if (likely(!pivots[offset])) + return ma_meta_end(node, type); + + if (likely(pivots[offset] == mas->max)) + return offset; + + return mt_pivots[type]; +} + +/* + * mas_leaf_max_gap() - Returns the largest gap in a leaf node + * @mas - the maple state + * + * Return: The maximum gap in the leaf. + */ +static unsigned long mas_leaf_max_gap(struct ma_state *mas) +{ + enum maple_type mt; + unsigned long pstart, gap, max_gap; + struct maple_node *mn; + unsigned long *pivots; + void __rcu **slots; + unsigned char i; + unsigned char max_piv; + + mt = mte_node_type(mas->node); + mn = mas_mn(mas); + slots = ma_slots(mn, mt); + max_gap = 0; + if (unlikely(ma_is_dense(mt))) { + gap = 0; + for (i = 0; i < mt_slots[mt]; i++) { + if (slots[i]) { + if (gap > max_gap) + max_gap = gap; + gap = 0; + } else { + gap++; + } + } + if (gap > max_gap) + max_gap = gap; + return max_gap; + } + + /* + * Check the first implied pivot optimizes the loop below and slot 1 may + * be skipped if there is a gap in slot 0. + */ + pivots = ma_pivots(mn, mt); + if (likely(!slots[0])) { + max_gap = pivots[0] - mas->min + 1; + i = 2; + } else { + i = 1; + } + + /* reduce max_piv as the special case is checked before the loop */ + max_piv = ma_data_end(mn, mt, pivots, mas->max) - 1; + /* + * Check end implied pivot which can only be a gap on the right most + * node. + */ + if (unlikely(mas->max == ULONG_MAX) && !slots[max_piv + 1]) { + gap = ULONG_MAX - pivots[max_piv]; + if (gap > max_gap) + max_gap = gap; + } + + for (; i <= max_piv; i++) { + /* data == no gap. */ + if (likely(slots[i])) + continue; + + pstart = pivots[i - 1]; + gap = pivots[i] - pstart; + if (gap > max_gap) + max_gap = gap; + + /* There cannot be two gaps in a row. */ + i++; + } + return max_gap; +} + +/* + * ma_max_gap() - Get the maximum gap in a maple node (non-leaf) + * @node: The maple node + * @gaps: The pointer to the gaps + * @mt: The maple node type + * @*off: Pointer to store the offset location of the gap. + * + * Uses the metadata data end to scan backwards across set gaps. + * + * Return: The maximum gap value + */ +static inline unsigned long +ma_max_gap(struct maple_node *node, unsigned long *gaps, enum maple_type mt, + unsigned char *off) +{ + unsigned char offset, i; + unsigned long max_gap = 0; + + i = offset = ma_meta_end(node, mt); + do { + if (gaps[i] > max_gap) { + max_gap = gaps[i]; + offset = i; + } + } while (i--); + + *off = offset; + return max_gap; +} + +/* + * mas_max_gap() - find the largest gap in a non-leaf node and set the slot. + * @mas: The maple state. + * + * If the metadata gap is set to MAPLE_ARANGE64_META_MAX, there is no gap. + * + * Return: The gap value. + */ +static inline unsigned long mas_max_gap(struct ma_state *mas) +{ + unsigned long *gaps; + unsigned char offset; + enum maple_type mt; + struct maple_node *node; + + mt = mte_node_type(mas->node); + if (ma_is_leaf(mt)) + return mas_leaf_max_gap(mas); + + node = mas_mn(mas); + offset = ma_meta_gap(node, mt); + if (offset == MAPLE_ARANGE64_META_MAX) + return 0; + + gaps = ma_gaps(node, mt); + return gaps[offset]; +} + +/* + * mas_parent_gap() - Set the parent gap and any gaps above, as needed + * @mas: The maple state + * @offset: The gap offset in the parent to set + * @new: The new gap value. + * + * Set the parent gap then continue to set the gap upwards, using the metadata + * of the parent to see if it is necessary to check the node above. + */ +static inline void mas_parent_gap(struct ma_state *mas, unsigned char offset, + unsigned long new) +{ + unsigned long meta_gap = 0; + struct maple_node *pnode; + struct maple_enode *penode; + unsigned long *pgaps; + unsigned char meta_offset; + enum maple_type pmt; + + pnode = mte_parent(mas->node); + pmt = mas_parent_enum(mas, mas->node); + penode = mt_mk_node(pnode, pmt); + pgaps = ma_gaps(pnode, pmt); + +ascend: + meta_offset = ma_meta_gap(pnode, pmt); + if (meta_offset == MAPLE_ARANGE64_META_MAX) + meta_gap = 0; + else + meta_gap = pgaps[meta_offset]; + + pgaps[offset] = new; + + if (meta_gap == new) + return; + + if (offset != meta_offset) { + if (meta_gap > new) + return; + + ma_set_meta_gap(pnode, pmt, offset); + } else if (new < meta_gap) { + meta_offset = 15; + new = ma_max_gap(pnode, pgaps, pmt, &meta_offset); + ma_set_meta_gap(pnode, pmt, meta_offset); + } + + if (ma_is_root(pnode)) + return; + + /* Go to the parent node. */ + pnode = mte_parent(penode); + pmt = mas_parent_enum(mas, penode); + pgaps = ma_gaps(pnode, pmt); + offset = mte_parent_slot(penode); + penode = mt_mk_node(pnode, pmt); + goto ascend; +} + +/* + * mas_update_gap() - Update a nodes gaps and propagate up if necessary. + * @mas - the maple state. + */ +static inline void mas_update_gap(struct ma_state *mas) +{ + unsigned char pslot; + unsigned long p_gap; + unsigned long max_gap; + + if (!mt_is_alloc(mas->tree)) + return; + + if (mte_is_root(mas->node)) + return; + + max_gap = mas_max_gap(mas); + + pslot = mte_parent_slot(mas->node); + p_gap = ma_gaps(mte_parent(mas->node), + mas_parent_enum(mas, mas->node))[pslot]; + + if (p_gap != max_gap) + mas_parent_gap(mas, pslot, max_gap); +} + +/* + * mas_adopt_children() - Set the parent pointer of all nodes in @parent to + * @parent with the slot encoded. + * @mas - the maple state (for the tree) + * @parent - the maple encoded node containing the children. + */ +static inline void mas_adopt_children(struct ma_state *mas, + struct maple_enode *parent) +{ + enum maple_type type = mte_node_type(parent); + struct maple_node *node = mas_mn(mas); + void __rcu **slots = ma_slots(node, type); + unsigned long *pivots = ma_pivots(node, type); + struct maple_enode *child; + unsigned char offset; + + offset = ma_data_end(node, type, pivots, mas->max); + do { + child = mas_slot_locked(mas, slots, offset); + mte_set_parent(child, parent, offset); + } while (offset--); +} + +/* + * mas_replace() - Replace a maple node in the tree with mas->node. Uses the + * parent encoding to locate the maple node in the tree. + * @mas - the ma_state to use for operations. + * @advanced - boolean to adopt the child nodes and free the old node (false) or + * leave the node (true) and handle the adoption and free elsewhere. + */ +static inline void mas_replace(struct ma_state *mas, bool advanced) + __must_hold(mas->tree->lock) +{ + struct maple_node *mn = mas_mn(mas); + struct maple_enode *old_enode; + unsigned char offset = 0; + void __rcu **slots = NULL; + + if (ma_is_root(mn)) { + old_enode = mas_root_locked(mas); + } else { + offset = mte_parent_slot(mas->node); + slots = ma_slots(mte_parent(mas->node), + mas_parent_enum(mas, mas->node)); + old_enode = mas_slot_locked(mas, slots, offset); + } + + if (!advanced && !mte_is_leaf(mas->node)) + mas_adopt_children(mas, mas->node); + + if (mte_is_root(mas->node)) { + mn->parent = ma_parent_ptr( + ((unsigned long)mas->tree | MA_ROOT_PARENT)); + rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node)); + mas_set_height(mas); + } else { + rcu_assign_pointer(slots[offset], mas->node); + } + + if (!advanced) + mas_free(mas, old_enode); +} + +/* + * mas_new_child() - Find the new child of a node. + * @mas: the maple state + * @child: the maple state to store the child. + */ +static inline bool mas_new_child(struct ma_state *mas, struct ma_state *child) + __must_hold(mas->tree->lock) +{ + enum maple_type mt; + unsigned char offset; + unsigned char end; + unsigned long *pivots; + struct maple_enode *entry; + struct maple_node *node; + void __rcu **slots; + + mt = mte_node_type(mas->node); + node = mas_mn(mas); + slots = ma_slots(node, mt); + pivots = ma_pivots(node, mt); + end = ma_data_end(node, mt, pivots, mas->max); + for (offset = mas->offset; offset <= end; offset++) { + entry = mas_slot_locked(mas, slots, offset); + if (mte_parent(entry) == node) { + *child = *mas; + mas->offset = offset + 1; + child->offset = offset; + mas_descend(child); + child->offset = 0; + return true; + } + } + return false; +} + +/* + * mab_shift_right() - Shift the data in mab right. Note, does not clean out the + * old data or set b_node->b_end. + * @b_node: the maple_big_node + * @shift: the shift count + */ +static inline void mab_shift_right(struct maple_big_node *b_node, + unsigned char shift) +{ + unsigned long size = b_node->b_end * sizeof(unsigned long); + + memmove(b_node->pivot + shift, b_node->pivot, size); + memmove(b_node->slot + shift, b_node->slot, size); + if (b_node->type == maple_arange_64) + memmove(b_node->gap + shift, b_node->gap, size); +} + +/* + * mab_middle_node() - Check if a middle node is needed (unlikely) + * @b_node: the maple_big_node that contains the data. + * @size: the amount of data in the b_node + * @split: the potential split location + * @slot_count: the size that can be stored in a single node being considered. + * + * Return: true if a middle node is required. + */ +static inline bool mab_middle_node(struct maple_big_node *b_node, int split, + unsigned char slot_count) +{ + unsigned char size = b_node->b_end; + + if (size >= 2 * slot_count) + return true; + + if (!b_node->slot[split] && (size >= 2 * slot_count - 1)) + return true; + + return false; +} + +/* + * mab_no_null_split() - ensure the split doesn't fall on a NULL + * @b_node: the maple_big_node with the data + * @split: the suggested split location + * @slot_count: the number of slots in the node being considered. + * + * Return: the split location. + */ +static inline int mab_no_null_split(struct maple_big_node *b_node, + unsigned char split, unsigned char slot_count) +{ + if (!b_node->slot[split]) { + /* + * If the split is less than the max slot && the right side will + * still be sufficient, then increment the split on NULL. + */ + if ((split < slot_count - 1) && + (b_node->b_end - split) > (mt_min_slots[b_node->type])) + split++; + else + split--; + } + return split; +} + +/* + * mab_calc_split() - Calculate the split location and if there needs to be two + * splits. + * @bn: The maple_big_node with the data + * @mid_split: The second split, if required. 0 otherwise. + * + * Return: The first split location. The middle split is set in @mid_split. + */ +static inline int mab_calc_split(struct ma_state *mas, + struct maple_big_node *bn, unsigned char *mid_split, unsigned long min) +{ + unsigned char b_end = bn->b_end; + int split = b_end / 2; /* Assume equal split. */ + unsigned char slot_min, slot_count = mt_slots[bn->type]; + + /* + * To support gap tracking, all NULL entries are kept together and a node cannot + * end on a NULL entry, with the exception of the left-most leaf. The + * limitation means that the split of a node must be checked for this condition + * and be able to put more data in one direction or the other. + */ + if (unlikely((mas->mas_flags & MA_STATE_BULK))) { + *mid_split = 0; + split = b_end - mt_min_slots[bn->type]; + + if (!ma_is_leaf(bn->type)) + return split; + + mas->mas_flags |= MA_STATE_REBALANCE; + if (!bn->slot[split]) + split--; + return split; + } + + /* + * Although extremely rare, it is possible to enter what is known as the 3-way + * split scenario. The 3-way split comes about by means of a store of a range + * that overwrites the end and beginning of two full nodes. The result is a set + * of entries that cannot be stored in 2 nodes. Sometimes, these two nodes can + * also be located in different parent nodes which are also full. This can + * carry upwards all the way to the root in the worst case. + */ + if (unlikely(mab_middle_node(bn, split, slot_count))) { + split = b_end / 3; + *mid_split = split * 2; + } else { + slot_min = mt_min_slots[bn->type]; + + *mid_split = 0; + /* + * Avoid having a range less than the slot count unless it + * causes one node to be deficient. + * NOTE: mt_min_slots is 1 based, b_end and split are zero. + */ + while (((bn->pivot[split] - min) < slot_count - 1) && + (split < slot_count - 1) && (b_end - split > slot_min)) + split++; + } + + /* Avoid ending a node on a NULL entry */ + split = mab_no_null_split(bn, split, slot_count); + if (!(*mid_split)) + return split; + + *mid_split = mab_no_null_split(bn, *mid_split, slot_count); + + return split; +} + +/* + * mas_mab_cp() - Copy data from a maple state inclusively to a maple_big_node + * and set @b_node->b_end to the next free slot. + * @mas: The maple state + * @mas_start: The starting slot to copy + * @mas_end: The end slot to copy (inclusively) + * @b_node: The maple_big_node to place the data + * @mab_start: The starting location in maple_big_node to store the data. + */ +static inline void mas_mab_cp(struct ma_state *mas, unsigned char mas_start, + unsigned char mas_end, struct maple_big_node *b_node, + unsigned char mab_start) +{ + enum maple_type mt; + struct maple_node *node; + void __rcu **slots; + unsigned long *pivots, *gaps; + int i = mas_start, j = mab_start; + unsigned char piv_end; + + node = mas_mn(mas); + mt = mte_node_type(mas->node); + pivots = ma_pivots(node, mt); + if (!i) { + b_node->pivot[j] = pivots[i++]; + if (unlikely(i > mas_end)) + goto complete; + j++; + } + + piv_end = min(mas_end, mt_pivots[mt]); + for (; i < piv_end; i++, j++) { + b_node->pivot[j] = pivots[i]; + if (unlikely(!b_node->pivot[j])) + break; + + if (unlikely(mas->max == b_node->pivot[j])) + goto complete; + } + + if (likely(i <= mas_end)) + b_node->pivot[j] = mas_safe_pivot(mas, pivots, i, mt); + +complete: + b_node->b_end = ++j; + j -= mab_start; + slots = ma_slots(node, mt); + memcpy(b_node->slot + mab_start, slots + mas_start, sizeof(void *) * j); + if (!ma_is_leaf(mt) && mt_is_alloc(mas->tree)) { + gaps = ma_gaps(node, mt); + memcpy(b_node->gap + mab_start, gaps + mas_start, + sizeof(unsigned long) * j); + } +} + +/* + * mas_leaf_set_meta() - Set the metadata of a leaf if possible. + * @mas: The maple state + * @node: The maple node + * @pivots: pointer to the maple node pivots + * @mt: The maple type + * @end: The assumed end + * + * Note, end may be incremented within this function but not modified at the + * source. This is fine since the metadata is the last thing to be stored in a + * node during a write. + */ +static inline void mas_leaf_set_meta(struct ma_state *mas, + struct maple_node *node, unsigned long *pivots, + enum maple_type mt, unsigned char end) +{ + /* There is no room for metadata already */ + if (mt_pivots[mt] <= end) + return; + + if (pivots[end] && pivots[end] < mas->max) + end++; + + if (end < mt_slots[mt] - 1) + ma_set_meta(node, mt, 0, end); +} + +/* + * mab_mas_cp() - Copy data from maple_big_node to a maple encoded node. + * @b_node: the maple_big_node that has the data + * @mab_start: the start location in @b_node. + * @mab_end: The end location in @b_node (inclusively) + * @mas: The maple state with the maple encoded node. + */ +static inline void mab_mas_cp(struct maple_big_node *b_node, + unsigned char mab_start, unsigned char mab_end, + struct ma_state *mas, bool new_max) +{ + int i, j = 0; + enum maple_type mt = mte_node_type(mas->node); + struct maple_node *node = mte_to_node(mas->node); + void __rcu **slots = ma_slots(node, mt); + unsigned long *pivots = ma_pivots(node, mt); + unsigned long *gaps = NULL; + unsigned char end; + + if (mab_end - mab_start > mt_pivots[mt]) + mab_end--; + + if (!pivots[mt_pivots[mt] - 1]) + slots[mt_pivots[mt]] = NULL; + + i = mab_start; + do { + pivots[j++] = b_node->pivot[i++]; + } while (i <= mab_end && likely(b_node->pivot[i])); + + memcpy(slots, b_node->slot + mab_start, + sizeof(void *) * (i - mab_start)); + + if (new_max) + mas->max = b_node->pivot[i - 1]; + + end = j - 1; + if (likely(!ma_is_leaf(mt) && mt_is_alloc(mas->tree))) { + unsigned long max_gap = 0; + unsigned char offset = 15; + + gaps = ma_gaps(node, mt); + do { + gaps[--j] = b_node->gap[--i]; + if (gaps[j] > max_gap) { + offset = j; + max_gap = gaps[j]; + } + } while (j); + + ma_set_meta(node, mt, offset, end); + } else { + mas_leaf_set_meta(mas, node, pivots, mt, end); + } +} + +/* + * mas_descend_adopt() - Descend through a sub-tree and adopt children. + * @mas: the maple state with the maple encoded node of the sub-tree. + * + * Descend through a sub-tree and adopt children who do not have the correct + * parents set. Follow the parents which have the correct parents as they are + * the new entries which need to be followed to find other incorrectly set + * parents. + */ +static inline void mas_descend_adopt(struct ma_state *mas) +{ + struct ma_state list[3], next[3]; + int i, n; + + /* + * At each level there may be up to 3 correct parent pointers which indicates + * the new nodes which need to be walked to find any new nodes at a lower level. + */ + + for (i = 0; i < 3; i++) { + list[i] = *mas; + list[i].offset = 0; + next[i].offset = 0; + } + next[0] = *mas; + + while (!mte_is_leaf(list[0].node)) { + n = 0; + for (i = 0; i < 3; i++) { + if (mas_is_none(&list[i])) + continue; + + if (i && list[i-1].node == list[i].node) + continue; + + while ((n < 3) && (mas_new_child(&list[i], &next[n]))) + n++; + + mas_adopt_children(&list[i], list[i].node); + } + + while (n < 3) + next[n++].node = MAS_NONE; + + /* descend by setting the list to the children */ + for (i = 0; i < 3; i++) + list[i] = next[i]; + } +} + +/* + * mas_bulk_rebalance() - Rebalance the end of a tree after a bulk insert. + * @mas: The maple state + * @end: The maple node end + * @mt: The maple node type + */ +static inline void mas_bulk_rebalance(struct ma_state *mas, unsigned char end, + enum maple_type mt) +{ + if (!(mas->mas_flags & MA_STATE_BULK)) + return; + + if (mte_is_root(mas->node)) + return; + + if (end > mt_min_slots[mt]) { + mas->mas_flags &= ~MA_STATE_REBALANCE; + return; + } +} + +/* + * mas_store_b_node() - Store an @entry into the b_node while also copying the + * data from a maple encoded node. + * @wr_mas: the maple write state + * @b_node: the maple_big_node to fill with data + * @offset_end: the offset to end copying + * + * Return: The actual end of the data stored in @b_node + */ +static inline void mas_store_b_node(struct ma_wr_state *wr_mas, + struct maple_big_node *b_node, unsigned char offset_end) +{ + unsigned char slot; + unsigned char b_end; + /* Possible underflow of piv will wrap back to 0 before use. */ + unsigned long piv; + struct ma_state *mas = wr_mas->mas; + + b_node->type = wr_mas->type; + b_end = 0; + slot = mas->offset; + if (slot) { + /* Copy start data up to insert. */ + mas_mab_cp(mas, 0, slot - 1, b_node, 0); + b_end = b_node->b_end; + piv = b_node->pivot[b_end - 1]; + } else + piv = mas->min - 1; + + if (piv + 1 < mas->index) { + /* Handle range starting after old range */ + b_node->slot[b_end] = wr_mas->content; + if (!wr_mas->content) + b_node->gap[b_end] = mas->index - 1 - piv; + b_node->pivot[b_end++] = mas->index - 1; + } + + /* Store the new entry. */ + mas->offset = b_end; + b_node->slot[b_end] = wr_mas->entry; + b_node->pivot[b_end] = mas->last; + + /* Appended. */ + if (mas->last >= mas->max) + goto b_end; + + /* Handle new range ending before old range ends */ + piv = mas_logical_pivot(mas, wr_mas->pivots, offset_end, wr_mas->type); + if (piv > mas->last) { + if (piv == ULONG_MAX) + mas_bulk_rebalance(mas, b_node->b_end, wr_mas->type); + + if (offset_end != slot) + wr_mas->content = mas_slot_locked(mas, wr_mas->slots, + offset_end); + + b_node->slot[++b_end] = wr_mas->content; + if (!wr_mas->content) + b_node->gap[b_end] = piv - mas->last + 1; + b_node->pivot[b_end] = piv; + } + + slot = offset_end + 1; + if (slot > wr_mas->node_end) + goto b_end; + + /* Copy end data to the end of the node. */ + mas_mab_cp(mas, slot, wr_mas->node_end + 1, b_node, ++b_end); + b_node->b_end--; + return; + +b_end: + b_node->b_end = b_end; +} + +/* + * mas_prev_sibling() - Find the previous node with the same parent. + * @mas: the maple state + * + * Return: True if there is a previous sibling, false otherwise. + */ +static inline bool mas_prev_sibling(struct ma_state *mas) +{ + unsigned int p_slot = mte_parent_slot(mas->node); + + if (mte_is_root(mas->node)) + return false; + + if (!p_slot) + return false; + + mas_ascend(mas); + mas->offset = p_slot - 1; + mas_descend(mas); + return true; +} + +/* + * mas_next_sibling() - Find the next node with the same parent. + * @mas: the maple state + * + * Return: true if there is a next sibling, false otherwise. + */ +static inline bool mas_next_sibling(struct ma_state *mas) +{ + MA_STATE(parent, mas->tree, mas->index, mas->last); + + if (mte_is_root(mas->node)) + return false; + + parent = *mas; + mas_ascend(&parent); + parent.offset = mte_parent_slot(mas->node) + 1; + if (parent.offset > mas_data_end(&parent)) + return false; + + *mas = parent; + mas_descend(mas); + return true; +} + +/* + * mte_node_or_node() - Return the encoded node or MAS_NONE. + * @enode: The encoded maple node. + * + * Shorthand to avoid setting %NULLs in the tree or maple_subtree_state. + * + * Return: @enode or MAS_NONE + */ +static inline struct maple_enode *mte_node_or_none(struct maple_enode *enode) +{ + if (enode) + return enode; + + return ma_enode_ptr(MAS_NONE); +} + +/* + * mas_wr_node_walk() - Find the correct offset for the index in the @mas. + * @wr_mas: The maple write state + * + * Uses mas_slot_locked() and does not need to worry about dead nodes. + */ +static inline void mas_wr_node_walk(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + unsigned char count; + unsigned char offset; + unsigned long index, min, max; + + if (unlikely(ma_is_dense(wr_mas->type))) { + wr_mas->r_max = wr_mas->r_min = mas->index; + mas->offset = mas->index = mas->min; + return; + } + + wr_mas->node = mas_mn(wr_mas->mas); + wr_mas->pivots = ma_pivots(wr_mas->node, wr_mas->type); + count = wr_mas->node_end = ma_data_end(wr_mas->node, wr_mas->type, + wr_mas->pivots, mas->max); + offset = mas->offset; + min = mas_safe_min(mas, wr_mas->pivots, offset); + if (unlikely(offset == count)) + goto max; + + max = wr_mas->pivots[offset]; + index = mas->index; + if (unlikely(index <= max)) + goto done; + + if (unlikely(!max && offset)) + goto max; + + min = max + 1; + while (++offset < count) { + max = wr_mas->pivots[offset]; + if (index <= max) + goto done; + else if (unlikely(!max)) + break; + + min = max + 1; + } + +max: + max = mas->max; +done: + wr_mas->r_max = max; + wr_mas->r_min = min; + wr_mas->offset_end = mas->offset = offset; +} + +/* + * mas_topiary_range() - Add a range of slots to the topiary. + * @mas: The maple state + * @destroy: The topiary to add the slots (usually destroy) + * @start: The starting slot inclusively + * @end: The end slot inclusively + */ +static inline void mas_topiary_range(struct ma_state *mas, + struct ma_topiary *destroy, unsigned char start, unsigned char end) +{ + void __rcu **slots; + unsigned char offset; + + MT_BUG_ON(mas->tree, mte_is_leaf(mas->node)); + slots = ma_slots(mas_mn(mas), mte_node_type(mas->node)); + for (offset = start; offset <= end; offset++) { + struct maple_enode *enode = mas_slot_locked(mas, slots, offset); + + if (mte_dead_node(enode)) + continue; + + mat_add(destroy, enode); + } +} + +/* + * mast_topiary() - Add the portions of the tree to the removal list; either to + * be freed or discarded (destroy walk). + * @mast: The maple_subtree_state. + */ +static inline void mast_topiary(struct maple_subtree_state *mast) +{ + MA_WR_STATE(wr_mas, mast->orig_l, NULL); + unsigned char r_start, r_end; + unsigned char l_start, l_end; + void __rcu **l_slots, **r_slots; + + wr_mas.type = mte_node_type(mast->orig_l->node); + mast->orig_l->index = mast->orig_l->last; + mas_wr_node_walk(&wr_mas); + l_start = mast->orig_l->offset + 1; + l_end = mas_data_end(mast->orig_l); + r_start = 0; + r_end = mast->orig_r->offset; + + if (r_end) + r_end--; + + l_slots = ma_slots(mas_mn(mast->orig_l), + mte_node_type(mast->orig_l->node)); + + r_slots = ma_slots(mas_mn(mast->orig_r), + mte_node_type(mast->orig_r->node)); + + if ((l_start < l_end) && + mte_dead_node(mas_slot_locked(mast->orig_l, l_slots, l_start))) { + l_start++; + } + + if (mte_dead_node(mas_slot_locked(mast->orig_r, r_slots, r_end))) { + if (r_end) + r_end--; + } + + if ((l_start > r_end) && (mast->orig_l->node == mast->orig_r->node)) + return; + + /* At the node where left and right sides meet, add the parts between */ + if (mast->orig_l->node == mast->orig_r->node) { + return mas_topiary_range(mast->orig_l, mast->destroy, + l_start, r_end); + } + + /* mast->orig_r is different and consumed. */ + if (mte_is_leaf(mast->orig_r->node)) + return; + + if (mte_dead_node(mas_slot_locked(mast->orig_l, l_slots, l_end))) + l_end--; + + + if (l_start <= l_end) + mas_topiary_range(mast->orig_l, mast->destroy, l_start, l_end); + + if (mte_dead_node(mas_slot_locked(mast->orig_r, r_slots, r_start))) + r_start++; + + if (r_start <= r_end) + mas_topiary_range(mast->orig_r, mast->destroy, 0, r_end); +} + +/* + * mast_rebalance_next() - Rebalance against the next node + * @mast: The maple subtree state + * @old_r: The encoded maple node to the right (next node). + */ +static inline void mast_rebalance_next(struct maple_subtree_state *mast) +{ + unsigned char b_end = mast->bn->b_end; + + mas_mab_cp(mast->orig_r, 0, mt_slot_count(mast->orig_r->node), + mast->bn, b_end); + mast->orig_r->last = mast->orig_r->max; +} + +/* + * mast_rebalance_prev() - Rebalance against the previous node + * @mast: The maple subtree state + * @old_l: The encoded maple node to the left (previous node) + */ +static inline void mast_rebalance_prev(struct maple_subtree_state *mast) +{ + unsigned char end = mas_data_end(mast->orig_l) + 1; + unsigned char b_end = mast->bn->b_end; + + mab_shift_right(mast->bn, end); + mas_mab_cp(mast->orig_l, 0, end - 1, mast->bn, 0); + mast->l->min = mast->orig_l->min; + mast->orig_l->index = mast->orig_l->min; + mast->bn->b_end = end + b_end; + mast->l->offset += end; +} + +/* + * mast_spanning_rebalance() - Rebalance nodes with nearest neighbour favouring + * the node to the right. Checking the nodes to the right then the left at each + * level upwards until root is reached. Free and destroy as needed. + * Data is copied into the @mast->bn. + * @mast: The maple_subtree_state. + */ +static inline +bool mast_spanning_rebalance(struct maple_subtree_state *mast) +{ + struct ma_state r_tmp = *mast->orig_r; + struct ma_state l_tmp = *mast->orig_l; + struct maple_enode *ancestor = NULL; + unsigned char start, end; + unsigned char depth = 0; + + r_tmp = *mast->orig_r; + l_tmp = *mast->orig_l; + do { + mas_ascend(mast->orig_r); + mas_ascend(mast->orig_l); + depth++; + if (!ancestor && + (mast->orig_r->node == mast->orig_l->node)) { + ancestor = mast->orig_r->node; + end = mast->orig_r->offset - 1; + start = mast->orig_l->offset + 1; + } + + if (mast->orig_r->offset < mas_data_end(mast->orig_r)) { + if (!ancestor) { + ancestor = mast->orig_r->node; + start = 0; + } + + mast->orig_r->offset++; + do { + mas_descend(mast->orig_r); + mast->orig_r->offset = 0; + depth--; + } while (depth); + + mast_rebalance_next(mast); + do { + unsigned char l_off = 0; + struct maple_enode *child = r_tmp.node; + + mas_ascend(&r_tmp); + if (ancestor == r_tmp.node) + l_off = start; + + if (r_tmp.offset) + r_tmp.offset--; + + if (l_off < r_tmp.offset) + mas_topiary_range(&r_tmp, mast->destroy, + l_off, r_tmp.offset); + + if (l_tmp.node != child) + mat_add(mast->free, child); + + } while (r_tmp.node != ancestor); + + *mast->orig_l = l_tmp; + return true; + + } else if (mast->orig_l->offset != 0) { + if (!ancestor) { + ancestor = mast->orig_l->node; + end = mas_data_end(mast->orig_l); + } + + mast->orig_l->offset--; + do { + mas_descend(mast->orig_l); + mast->orig_l->offset = + mas_data_end(mast->orig_l); + depth--; + } while (depth); + + mast_rebalance_prev(mast); + do { + unsigned char r_off; + struct maple_enode *child = l_tmp.node; + + mas_ascend(&l_tmp); + if (ancestor == l_tmp.node) + r_off = end; + else + r_off = mas_data_end(&l_tmp); + + if (l_tmp.offset < r_off) + l_tmp.offset++; + + if (l_tmp.offset < r_off) + mas_topiary_range(&l_tmp, mast->destroy, + l_tmp.offset, r_off); + + if (r_tmp.node != child) + mat_add(mast->free, child); + + } while (l_tmp.node != ancestor); + + *mast->orig_r = r_tmp; + return true; + } + } while (!mte_is_root(mast->orig_r->node)); + + *mast->orig_r = r_tmp; + *mast->orig_l = l_tmp; + return false; +} + +/* + * mast_ascend_free() - Add current original maple state nodes to the free list + * and ascend. + * @mast: the maple subtree state. + * + * Ascend the original left and right sides and add the previous nodes to the + * free list. Set the slots to point to the correct location in the new nodes. + */ +static inline void +mast_ascend_free(struct maple_subtree_state *mast) +{ + MA_WR_STATE(wr_mas, mast->orig_r, NULL); + struct maple_enode *left = mast->orig_l->node; + struct maple_enode *right = mast->orig_r->node; + + mas_ascend(mast->orig_l); + mas_ascend(mast->orig_r); + mat_add(mast->free, left); + + if (left != right) + mat_add(mast->free, right); + + mast->orig_r->offset = 0; + mast->orig_r->index = mast->r->max; + /* last should be larger than or equal to index */ + if (mast->orig_r->last < mast->orig_r->index) + mast->orig_r->last = mast->orig_r->index; + /* + * The node may not contain the value so set slot to ensure all + * of the nodes contents are freed or destroyed. + */ + wr_mas.type = mte_node_type(mast->orig_r->node); + mas_wr_node_walk(&wr_mas); + /* Set up the left side of things */ + mast->orig_l->offset = 0; + mast->orig_l->index = mast->l->min; + wr_mas.mas = mast->orig_l; + wr_mas.type = mte_node_type(mast->orig_l->node); + mas_wr_node_walk(&wr_mas); + + mast->bn->type = wr_mas.type; +} + +/* + * mas_new_ma_node() - Create and return a new maple node. Helper function. + * @mas: the maple state with the allocations. + * @b_node: the maple_big_node with the type encoding. + * + * Use the node type from the maple_big_node to allocate a new node from the + * ma_state. This function exists mainly for code readability. + * + * Return: A new maple encoded node + */ +static inline struct maple_enode +*mas_new_ma_node(struct ma_state *mas, struct maple_big_node *b_node) +{ + return mt_mk_node(ma_mnode_ptr(mas_pop_node(mas)), b_node->type); +} + +/* + * mas_mab_to_node() - Set up right and middle nodes + * + * @mas: the maple state that contains the allocations. + * @b_node: the node which contains the data. + * @left: The pointer which will have the left node + * @right: The pointer which may have the right node + * @middle: the pointer which may have the middle node (rare) + * @mid_split: the split location for the middle node + * + * Return: the split of left. + */ +static inline unsigned char mas_mab_to_node(struct ma_state *mas, + struct maple_big_node *b_node, struct maple_enode **left, + struct maple_enode **right, struct maple_enode **middle, + unsigned char *mid_split, unsigned long min) +{ + unsigned char split = 0; + unsigned char slot_count = mt_slots[b_node->type]; + + *left = mas_new_ma_node(mas, b_node); + *right = NULL; + *middle = NULL; + *mid_split = 0; + + if (b_node->b_end < slot_count) { + split = b_node->b_end; + } else { + split = mab_calc_split(mas, b_node, mid_split, min); + *right = mas_new_ma_node(mas, b_node); + } + + if (*mid_split) + *middle = mas_new_ma_node(mas, b_node); + + return split; + +} + +/* + * mab_set_b_end() - Add entry to b_node at b_node->b_end and increment the end + * pointer. + * @b_node - the big node to add the entry + * @mas - the maple state to get the pivot (mas->max) + * @entry - the entry to add, if NULL nothing happens. + */ +static inline void mab_set_b_end(struct maple_big_node *b_node, + struct ma_state *mas, + void *entry) +{ + if (!entry) + return; + + b_node->slot[b_node->b_end] = entry; + if (mt_is_alloc(mas->tree)) + b_node->gap[b_node->b_end] = mas_max_gap(mas); + b_node->pivot[b_node->b_end++] = mas->max; +} + +/* + * mas_set_split_parent() - combine_then_separate helper function. Sets the parent + * of @mas->node to either @left or @right, depending on @slot and @split + * + * @mas - the maple state with the node that needs a parent + * @left - possible parent 1 + * @right - possible parent 2 + * @slot - the slot the mas->node was placed + * @split - the split location between @left and @right + */ +static inline void mas_set_split_parent(struct ma_state *mas, + struct maple_enode *left, + struct maple_enode *right, + unsigned char *slot, unsigned char split) +{ + if (mas_is_none(mas)) + return; + + if ((*slot) <= split) + mte_set_parent(mas->node, left, *slot); + else if (right) + mte_set_parent(mas->node, right, (*slot) - split - 1); + + (*slot)++; +} + +/* + * mte_mid_split_check() - Check if the next node passes the mid-split + * @**l: Pointer to left encoded maple node. + * @**m: Pointer to middle encoded maple node. + * @**r: Pointer to right encoded maple node. + * @slot: The offset + * @*split: The split location. + * @mid_split: The middle split. + */ +static inline void mte_mid_split_check(struct maple_enode **l, + struct maple_enode **r, + struct maple_enode *right, + unsigned char slot, + unsigned char *split, + unsigned char mid_split) +{ + if (*r == right) + return; + + if (slot < mid_split) + return; + + *l = *r; + *r = right; + *split = mid_split; +} + +/* + * mast_set_split_parents() - Helper function to set three nodes parents. Slot + * is taken from @mast->l. + * @mast - the maple subtree state + * @left - the left node + * @right - the right node + * @split - the split location. + */ +static inline void mast_set_split_parents(struct maple_subtree_state *mast, + struct maple_enode *left, + struct maple_enode *middle, + struct maple_enode *right, + unsigned char split, + unsigned char mid_split) +{ + unsigned char slot; + struct maple_enode *l = left; + struct maple_enode *r = right; + + if (mas_is_none(mast->l)) + return; + + if (middle) + r = middle; + + slot = mast->l->offset; + + mte_mid_split_check(&l, &r, right, slot, &split, mid_split); + mas_set_split_parent(mast->l, l, r, &slot, split); + + mte_mid_split_check(&l, &r, right, slot, &split, mid_split); + mas_set_split_parent(mast->m, l, r, &slot, split); + + mte_mid_split_check(&l, &r, right, slot, &split, mid_split); + mas_set_split_parent(mast->r, l, r, &slot, split); +} + +/* + * mas_wmb_replace() - Write memory barrier and replace + * @mas: The maple state + * @free: the maple topiary list of nodes to free + * @destroy: The maple topiary list of nodes to destroy (walk and free) + * + * Updates gap as necessary. + */ +static inline void mas_wmb_replace(struct ma_state *mas, + struct ma_topiary *free, + struct ma_topiary *destroy) +{ + /* All nodes must see old data as dead prior to replacing that data */ + smp_wmb(); /* Needed for RCU */ + + /* Insert the new data in the tree */ + mas_replace(mas, true); + + if (!mte_is_leaf(mas->node)) + mas_descend_adopt(mas); + + mas_mat_free(mas, free); + + if (destroy) + mas_mat_destroy(mas, destroy); + + if (mte_is_leaf(mas->node)) + return; + + mas_update_gap(mas); +} + +/* + * mast_new_root() - Set a new tree root during subtree creation + * @mast: The maple subtree state + * @mas: The maple state + */ +static inline void mast_new_root(struct maple_subtree_state *mast, + struct ma_state *mas) +{ + mas_mn(mast->l)->parent = + ma_parent_ptr(((unsigned long)mas->tree | MA_ROOT_PARENT)); + if (!mte_dead_node(mast->orig_l->node) && + !mte_is_root(mast->orig_l->node)) { + do { + mast_ascend_free(mast); + mast_topiary(mast); + } while (!mte_is_root(mast->orig_l->node)); + } + if ((mast->orig_l->node != mas->node) && + (mast->l->depth > mas_mt_height(mas))) { + mat_add(mast->free, mas->node); + } +} + +/* + * mast_cp_to_nodes() - Copy data out to nodes. + * @mast: The maple subtree state + * @left: The left encoded maple node + * @middle: The middle encoded maple node + * @right: The right encoded maple node + * @split: The location to split between left and (middle ? middle : right) + * @mid_split: The location to split between middle and right. + */ +static inline void mast_cp_to_nodes(struct maple_subtree_state *mast, + struct maple_enode *left, struct maple_enode *middle, + struct maple_enode *right, unsigned char split, unsigned char mid_split) +{ + bool new_lmax = true; + + mast->l->node = mte_node_or_none(left); + mast->m->node = mte_node_or_none(middle); + mast->r->node = mte_node_or_none(right); + + mast->l->min = mast->orig_l->min; + if (split == mast->bn->b_end) { + mast->l->max = mast->orig_r->max; + new_lmax = false; + } + + mab_mas_cp(mast->bn, 0, split, mast->l, new_lmax); + + if (middle) { + mab_mas_cp(mast->bn, 1 + split, mid_split, mast->m, true); + mast->m->min = mast->bn->pivot[split] + 1; + split = mid_split; + } + + mast->r->max = mast->orig_r->max; + if (right) { + mab_mas_cp(mast->bn, 1 + split, mast->bn->b_end, mast->r, false); + mast->r->min = mast->bn->pivot[split] + 1; + } +} + +/* + * mast_combine_cp_left - Copy in the original left side of the tree into the + * combined data set in the maple subtree state big node. + * @mast: The maple subtree state + */ +static inline void mast_combine_cp_left(struct maple_subtree_state *mast) +{ + unsigned char l_slot = mast->orig_l->offset; + + if (!l_slot) + return; + + mas_mab_cp(mast->orig_l, 0, l_slot - 1, mast->bn, 0); +} + +/* + * mast_combine_cp_right: Copy in the original right side of the tree into the + * combined data set in the maple subtree state big node. + * @mast: The maple subtree state + */ +static inline void mast_combine_cp_right(struct maple_subtree_state *mast) +{ + if (mast->bn->pivot[mast->bn->b_end - 1] >= mast->orig_r->max) + return; + + mas_mab_cp(mast->orig_r, mast->orig_r->offset + 1, + mt_slot_count(mast->orig_r->node), mast->bn, + mast->bn->b_end); + mast->orig_r->last = mast->orig_r->max; +} + +/* + * mast_sufficient: Check if the maple subtree state has enough data in the big + * node to create at least one sufficient node + * @mast: the maple subtree state + */ +static inline bool mast_sufficient(struct maple_subtree_state *mast) +{ + if (mast->bn->b_end > mt_min_slot_count(mast->orig_l->node)) + return true; + + return false; +} + +/* + * mast_overflow: Check if there is too much data in the subtree state for a + * single node. + * @mast: The maple subtree state + */ +static inline bool mast_overflow(struct maple_subtree_state *mast) +{ + if (mast->bn->b_end >= mt_slot_count(mast->orig_l->node)) + return true; + + return false; +} + +static inline void *mtree_range_walk(struct ma_state *mas) +{ + unsigned long *pivots; + unsigned char offset; + struct maple_node *node; + struct maple_enode *next, *last; + enum maple_type type; + void __rcu **slots; + unsigned char end; + unsigned long max, min; + unsigned long prev_max, prev_min; + + last = next = mas->node; + prev_min = min = mas->min; + max = mas->max; + do { + offset = 0; + last = next; + node = mte_to_node(next); + type = mte_node_type(next); + pivots = ma_pivots(node, type); + end = ma_data_end(node, type, pivots, max); + if (unlikely(ma_dead_node(node))) + goto dead_node; + + if (pivots[offset] >= mas->index) { + prev_max = max; + prev_min = min; + max = pivots[offset]; + goto next; + } + + do { + offset++; + } while ((offset < end) && (pivots[offset] < mas->index)); + + prev_min = min; + min = pivots[offset - 1] + 1; + prev_max = max; + if (likely(offset < end && pivots[offset])) + max = pivots[offset]; + +next: + slots = ma_slots(node, type); + next = mt_slot(mas->tree, slots, offset); + if (unlikely(ma_dead_node(node))) + goto dead_node; + } while (!ma_is_leaf(type)); + + mas->offset = offset; + mas->index = min; + mas->last = max; + mas->min = prev_min; + mas->max = prev_max; + mas->node = last; + return (void *) next; + +dead_node: + mas_reset(mas); + return NULL; +} + +/* + * mas_spanning_rebalance() - Rebalance across two nodes which may not be peers. + * @mas: The starting maple state + * @mast: The maple_subtree_state, keeps track of 4 maple states. + * @count: The estimated count of iterations needed. + * + * Follow the tree upwards from @l_mas and @r_mas for @count, or until the root + * is hit. First @b_node is split into two entries which are inserted into the + * next iteration of the loop. @b_node is returned populated with the final + * iteration. @mas is used to obtain allocations. orig_l_mas keeps track of the + * nodes that will remain active by using orig_l_mas->index and orig_l_mas->last + * to account of what has been copied into the new sub-tree. The update of + * orig_l_mas->last is used in mas_consume to find the slots that will need to + * be either freed or destroyed. orig_l_mas->depth keeps track of the height of + * the new sub-tree in case the sub-tree becomes the full tree. + * + * Return: the number of elements in b_node during the last loop. + */ +static int mas_spanning_rebalance(struct ma_state *mas, + struct maple_subtree_state *mast, unsigned char count) +{ + unsigned char split, mid_split; + unsigned char slot = 0; + struct maple_enode *left = NULL, *middle = NULL, *right = NULL; + + MA_STATE(l_mas, mas->tree, mas->index, mas->index); + MA_STATE(r_mas, mas->tree, mas->index, mas->last); + MA_STATE(m_mas, mas->tree, mas->index, mas->index); + MA_TOPIARY(free, mas->tree); + MA_TOPIARY(destroy, mas->tree); + + /* + * The tree needs to be rebalanced and leaves need to be kept at the same level. + * Rebalancing is done by use of the ``struct maple_topiary``. + */ + mast->l = &l_mas; + mast->m = &m_mas; + mast->r = &r_mas; + mast->free = &free; + mast->destroy = &destroy; + l_mas.node = r_mas.node = m_mas.node = MAS_NONE; + if (!(mast->orig_l->min && mast->orig_r->max == ULONG_MAX) && + unlikely(mast->bn->b_end <= mt_min_slots[mast->bn->type])) + mast_spanning_rebalance(mast); + + mast->orig_l->depth = 0; + + /* + * Each level of the tree is examined and balanced, pushing data to the left or + * right, or rebalancing against left or right nodes is employed to avoid + * rippling up the tree to limit the amount of churn. Once a new sub-section of + * the tree is created, there may be a mix of new and old nodes. The old nodes + * will have the incorrect parent pointers and currently be in two trees: the + * original tree and the partially new tree. To remedy the parent pointers in + * the old tree, the new data is swapped into the active tree and a walk down + * the tree is performed and the parent pointers are updated. + * See mas_descend_adopt() for more information.. + */ + while (count--) { + mast->bn->b_end--; + mast->bn->type = mte_node_type(mast->orig_l->node); + split = mas_mab_to_node(mas, mast->bn, &left, &right, &middle, + &mid_split, mast->orig_l->min); + mast_set_split_parents(mast, left, middle, right, split, + mid_split); + mast_cp_to_nodes(mast, left, middle, right, split, mid_split); + + /* + * Copy data from next level in the tree to mast->bn from next + * iteration + */ + memset(mast->bn, 0, sizeof(struct maple_big_node)); + mast->bn->type = mte_node_type(left); + mast->orig_l->depth++; + + /* Root already stored in l->node. */ + if (mas_is_root_limits(mast->l)) + goto new_root; + + mast_ascend_free(mast); + mast_combine_cp_left(mast); + l_mas.offset = mast->bn->b_end; + mab_set_b_end(mast->bn, &l_mas, left); + mab_set_b_end(mast->bn, &m_mas, middle); + mab_set_b_end(mast->bn, &r_mas, right); + + /* Copy anything necessary out of the right node. */ + mast_combine_cp_right(mast); + mast_topiary(mast); + mast->orig_l->last = mast->orig_l->max; + + if (mast_sufficient(mast)) + continue; + + if (mast_overflow(mast)) + continue; + + /* May be a new root stored in mast->bn */ + if (mas_is_root_limits(mast->orig_l)) + break; + + mast_spanning_rebalance(mast); + + /* rebalancing from other nodes may require another loop. */ + if (!count) + count++; + } + + l_mas.node = mt_mk_node(ma_mnode_ptr(mas_pop_node(mas)), + mte_node_type(mast->orig_l->node)); + mast->orig_l->depth++; + mab_mas_cp(mast->bn, 0, mt_slots[mast->bn->type] - 1, &l_mas, true); + mte_set_parent(left, l_mas.node, slot); + if (middle) + mte_set_parent(middle, l_mas.node, ++slot); + + if (right) + mte_set_parent(right, l_mas.node, ++slot); + + if (mas_is_root_limits(mast->l)) { +new_root: + mast_new_root(mast, mas); + } else { + mas_mn(&l_mas)->parent = mas_mn(mast->orig_l)->parent; + } + + if (!mte_dead_node(mast->orig_l->node)) + mat_add(&free, mast->orig_l->node); + + mas->depth = mast->orig_l->depth; + *mast->orig_l = l_mas; + mte_set_node_dead(mas->node); + + /* Set up mas for insertion. */ + mast->orig_l->depth = mas->depth; + mast->orig_l->alloc = mas->alloc; + *mas = *mast->orig_l; + mas_wmb_replace(mas, &free, &destroy); + mtree_range_walk(mas); + return mast->bn->b_end; +} + +/* + * mas_rebalance() - Rebalance a given node. + * @mas: The maple state + * @b_node: The big maple node. + * + * Rebalance two nodes into a single node or two new nodes that are sufficient. + * Continue upwards until tree is sufficient. + * + * Return: the number of elements in b_node during the last loop. + */ +static inline int mas_rebalance(struct ma_state *mas, + struct maple_big_node *b_node) +{ + char empty_count = mas_mt_height(mas); + struct maple_subtree_state mast; + unsigned char shift, b_end = ++b_node->b_end; + + MA_STATE(l_mas, mas->tree, mas->index, mas->last); + MA_STATE(r_mas, mas->tree, mas->index, mas->last); + + trace_ma_op(__func__, mas); + + /* + * Rebalancing occurs if a node is insufficient. Data is rebalanced + * against the node to the right if it exists, otherwise the node to the + * left of this node is rebalanced against this node. If rebalancing + * causes just one node to be produced instead of two, then the parent + * is also examined and rebalanced if it is insufficient. Every level + * tries to combine the data in the same way. If one node contains the + * entire range of the tree, then that node is used as a new root node. + */ + mas_node_count(mas, 1 + empty_count * 3); + if (mas_is_err(mas)) + return 0; + + mast.orig_l = &l_mas; + mast.orig_r = &r_mas; + mast.bn = b_node; + mast.bn->type = mte_node_type(mas->node); + + l_mas = r_mas = *mas; + + if (mas_next_sibling(&r_mas)) { + mas_mab_cp(&r_mas, 0, mt_slot_count(r_mas.node), b_node, b_end); + r_mas.last = r_mas.index = r_mas.max; + } else { + mas_prev_sibling(&l_mas); + shift = mas_data_end(&l_mas) + 1; + mab_shift_right(b_node, shift); + mas->offset += shift; + mas_mab_cp(&l_mas, 0, shift - 1, b_node, 0); + b_node->b_end = shift + b_end; + l_mas.index = l_mas.last = l_mas.min; + } + + return mas_spanning_rebalance(mas, &mast, empty_count); +} + +/* + * mas_destroy_rebalance() - Rebalance left-most node while destroying the maple + * state. + * @mas: The maple state + * @end: The end of the left-most node. + * + * During a mass-insert event (such as forking), it may be necessary to + * rebalance the left-most node when it is not sufficient. + */ +static inline void mas_destroy_rebalance(struct ma_state *mas, unsigned char end) +{ + enum maple_type mt = mte_node_type(mas->node); + struct maple_node reuse, *newnode, *parent, *new_left, *left, *node; + struct maple_enode *eparent; + unsigned char offset, tmp, split = mt_slots[mt] / 2; + void __rcu **l_slots, **slots; + unsigned long *l_pivs, *pivs, gap; + bool in_rcu = mt_in_rcu(mas->tree); + + MA_STATE(l_mas, mas->tree, mas->index, mas->last); + + l_mas = *mas; + mas_prev_sibling(&l_mas); + + /* set up node. */ + if (in_rcu) { + /* Allocate for both left and right as well as parent. */ + mas_node_count(mas, 3); + if (mas_is_err(mas)) + return; + + newnode = mas_pop_node(mas); + } else { + newnode = &reuse; + } + + node = mas_mn(mas); + newnode->parent = node->parent; + slots = ma_slots(newnode, mt); + pivs = ma_pivots(newnode, mt); + left = mas_mn(&l_mas); + l_slots = ma_slots(left, mt); + l_pivs = ma_pivots(left, mt); + if (!l_slots[split]) + split++; + tmp = mas_data_end(&l_mas) - split; + + memcpy(slots, l_slots + split + 1, sizeof(void *) * tmp); + memcpy(pivs, l_pivs + split + 1, sizeof(unsigned long) * tmp); + pivs[tmp] = l_mas.max; + memcpy(slots + tmp, ma_slots(node, mt), sizeof(void *) * end); + memcpy(pivs + tmp, ma_pivots(node, mt), sizeof(unsigned long) * end); + + l_mas.max = l_pivs[split]; + mas->min = l_mas.max + 1; + eparent = mt_mk_node(mte_parent(l_mas.node), + mas_parent_enum(&l_mas, l_mas.node)); + tmp += end; + if (!in_rcu) { + unsigned char max_p = mt_pivots[mt]; + unsigned char max_s = mt_slots[mt]; + + if (tmp < max_p) + memset(pivs + tmp, 0, + sizeof(unsigned long *) * (max_p - tmp)); + + if (tmp < mt_slots[mt]) + memset(slots + tmp, 0, sizeof(void *) * (max_s - tmp)); + + memcpy(node, newnode, sizeof(struct maple_node)); + ma_set_meta(node, mt, 0, tmp - 1); + mte_set_pivot(eparent, mte_parent_slot(l_mas.node), + l_pivs[split]); + + /* Remove data from l_pivs. */ + tmp = split + 1; + memset(l_pivs + tmp, 0, sizeof(unsigned long) * (max_p - tmp)); + memset(l_slots + tmp, 0, sizeof(void *) * (max_s - tmp)); + ma_set_meta(left, mt, 0, split); + + goto done; + } + + /* RCU requires replacing both l_mas, mas, and parent. */ + mas->node = mt_mk_node(newnode, mt); + ma_set_meta(newnode, mt, 0, tmp); + + new_left = mas_pop_node(mas); + new_left->parent = left->parent; + mt = mte_node_type(l_mas.node); + slots = ma_slots(new_left, mt); + pivs = ma_pivots(new_left, mt); + memcpy(slots, l_slots, sizeof(void *) * split); + memcpy(pivs, l_pivs, sizeof(unsigned long) * split); + ma_set_meta(new_left, mt, 0, split); + l_mas.node = mt_mk_node(new_left, mt); + + /* replace parent. */ + offset = mte_parent_slot(mas->node); + mt = mas_parent_enum(&l_mas, l_mas.node); + parent = mas_pop_node(mas); + slots = ma_slots(parent, mt); + pivs = ma_pivots(parent, mt); + memcpy(parent, mte_to_node(eparent), sizeof(struct maple_node)); + rcu_assign_pointer(slots[offset], mas->node); + rcu_assign_pointer(slots[offset - 1], l_mas.node); + pivs[offset - 1] = l_mas.max; + eparent = mt_mk_node(parent, mt); +done: + gap = mas_leaf_max_gap(mas); + mte_set_gap(eparent, mte_parent_slot(mas->node), gap); + gap = mas_leaf_max_gap(&l_mas); + mte_set_gap(eparent, mte_parent_slot(l_mas.node), gap); + mas_ascend(mas); + + if (in_rcu) + mas_replace(mas, false); + + mas_update_gap(mas); +} + +/* + * mas_split_final_node() - Split the final node in a subtree operation. + * @mast: the maple subtree state + * @mas: The maple state + * @height: The height of the tree in case it's a new root. + */ +static inline bool mas_split_final_node(struct maple_subtree_state *mast, + struct ma_state *mas, int height) +{ + struct maple_enode *ancestor; + + if (mte_is_root(mas->node)) { + if (mt_is_alloc(mas->tree)) + mast->bn->type = maple_arange_64; + else + mast->bn->type = maple_range_64; + mas->depth = height; + } + /* + * Only a single node is used here, could be root. + * The Big_node data should just fit in a single node. + */ + ancestor = mas_new_ma_node(mas, mast->bn); + mte_set_parent(mast->l->node, ancestor, mast->l->offset); + mte_set_parent(mast->r->node, ancestor, mast->r->offset); + mte_to_node(ancestor)->parent = mas_mn(mas)->parent; + + mast->l->node = ancestor; + mab_mas_cp(mast->bn, 0, mt_slots[mast->bn->type] - 1, mast->l, true); + mas->offset = mast->bn->b_end - 1; + return true; +} + +/* + * mast_fill_bnode() - Copy data into the big node in the subtree state + * @mast: The maple subtree state + * @mas: the maple state + * @skip: The number of entries to skip for new nodes insertion. + */ +static inline void mast_fill_bnode(struct maple_subtree_state *mast, + struct ma_state *mas, + unsigned char skip) +{ + bool cp = true; + struct maple_enode *old = mas->node; + unsigned char split; + + memset(mast->bn->gap, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->gap)); + memset(mast->bn->slot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->slot)); + memset(mast->bn->pivot, 0, sizeof(unsigned long) * ARRAY_SIZE(mast->bn->pivot)); + mast->bn->b_end = 0; + + if (mte_is_root(mas->node)) { + cp = false; + } else { + mas_ascend(mas); + mat_add(mast->free, old); + mas->offset = mte_parent_slot(mas->node); + } + + if (cp && mast->l->offset) + mas_mab_cp(mas, 0, mast->l->offset - 1, mast->bn, 0); + + split = mast->bn->b_end; + mab_set_b_end(mast->bn, mast->l, mast->l->node); + mast->r->offset = mast->bn->b_end; + mab_set_b_end(mast->bn, mast->r, mast->r->node); + if (mast->bn->pivot[mast->bn->b_end - 1] == mas->max) + cp = false; + + if (cp) + mas_mab_cp(mas, split + skip, mt_slot_count(mas->node) - 1, + mast->bn, mast->bn->b_end); + + mast->bn->b_end--; + mast->bn->type = mte_node_type(mas->node); +} + +/* + * mast_split_data() - Split the data in the subtree state big node into regular + * nodes. + * @mast: The maple subtree state + * @mas: The maple state + * @split: The location to split the big node + */ +static inline void mast_split_data(struct maple_subtree_state *mast, + struct ma_state *mas, unsigned char split) +{ + unsigned char p_slot; + + mab_mas_cp(mast->bn, 0, split, mast->l, true); + mte_set_pivot(mast->r->node, 0, mast->r->max); + mab_mas_cp(mast->bn, split + 1, mast->bn->b_end, mast->r, false); + mast->l->offset = mte_parent_slot(mas->node); + mast->l->max = mast->bn->pivot[split]; + mast->r->min = mast->l->max + 1; + if (mte_is_leaf(mas->node)) + return; + + p_slot = mast->orig_l->offset; + mas_set_split_parent(mast->orig_l, mast->l->node, mast->r->node, + &p_slot, split); + mas_set_split_parent(mast->orig_r, mast->l->node, mast->r->node, + &p_slot, split); +} + +/* + * mas_push_data() - Instead of splitting a node, it is beneficial to push the + * data to the right or left node if there is room. + * @mas: The maple state + * @height: The current height of the maple state + * @mast: The maple subtree state + * @left: Push left or not. + * + * Keeping the height of the tree low means faster lookups. + * + * Return: True if pushed, false otherwise. + */ +static inline bool mas_push_data(struct ma_state *mas, int height, + struct maple_subtree_state *mast, bool left) +{ + unsigned char slot_total = mast->bn->b_end; + unsigned char end, space, split; + + MA_STATE(tmp_mas, mas->tree, mas->index, mas->last); + tmp_mas = *mas; + tmp_mas.depth = mast->l->depth; + + if (left && !mas_prev_sibling(&tmp_mas)) + return false; + else if (!left && !mas_next_sibling(&tmp_mas)) + return false; + + end = mas_data_end(&tmp_mas); + slot_total += end; + space = 2 * mt_slot_count(mas->node) - 2; + /* -2 instead of -1 to ensure there isn't a triple split */ + if (ma_is_leaf(mast->bn->type)) + space--; + + if (mas->max == ULONG_MAX) + space--; + + if (slot_total >= space) + return false; + + /* Get the data; Fill mast->bn */ + mast->bn->b_end++; + if (left) { + mab_shift_right(mast->bn, end + 1); + mas_mab_cp(&tmp_mas, 0, end, mast->bn, 0); + mast->bn->b_end = slot_total + 1; + } else { + mas_mab_cp(&tmp_mas, 0, end, mast->bn, mast->bn->b_end); + } + + /* Configure mast for splitting of mast->bn */ + split = mt_slots[mast->bn->type] - 2; + if (left) { + /* Switch mas to prev node */ + mat_add(mast->free, mas->node); + *mas = tmp_mas; + /* Start using mast->l for the left side. */ + tmp_mas.node = mast->l->node; + *mast->l = tmp_mas; + } else { + mat_add(mast->free, tmp_mas.node); + tmp_mas.node = mast->r->node; + *mast->r = tmp_mas; + split = slot_total - split; + } + split = mab_no_null_split(mast->bn, split, mt_slots[mast->bn->type]); + /* Update parent slot for split calculation. */ + if (left) + mast->orig_l->offset += end + 1; + + mast_split_data(mast, mas, split); + mast_fill_bnode(mast, mas, 2); + mas_split_final_node(mast, mas, height + 1); + return true; +} + +/* + * mas_split() - Split data that is too big for one node into two. + * @mas: The maple state + * @b_node: The maple big node + * Return: 1 on success, 0 on failure. + */ +static int mas_split(struct ma_state *mas, struct maple_big_node *b_node) +{ + + struct maple_subtree_state mast; + int height = 0; + unsigned char mid_split, split = 0; + + /* + * Splitting is handled differently from any other B-tree; the Maple + * Tree splits upwards. Splitting up means that the split operation + * occurs when the walk of the tree hits the leaves and not on the way + * down. The reason for splitting up is that it is impossible to know + * how much space will be needed until the leaf is (or leaves are) + * reached. Since overwriting data is allowed and a range could + * overwrite more than one range or result in changing one entry into 3 + * entries, it is impossible to know if a split is required until the + * data is examined. + * + * Splitting is a balancing act between keeping allocations to a minimum + * and avoiding a 'jitter' event where a tree is expanded to make room + * for an entry followed by a contraction when the entry is removed. To + * accomplish the balance, there are empty slots remaining in both left + * and right nodes after a split. + */ + MA_STATE(l_mas, mas->tree, mas->index, mas->last); + MA_STATE(r_mas, mas->tree, mas->index, mas->last); + MA_STATE(prev_l_mas, mas->tree, mas->index, mas->last); + MA_STATE(prev_r_mas, mas->tree, mas->index, mas->last); + MA_TOPIARY(mat, mas->tree); + + trace_ma_op(__func__, mas); + mas->depth = mas_mt_height(mas); + /* Allocation failures will happen early. */ + mas_node_count(mas, 1 + mas->depth * 2); + if (mas_is_err(mas)) + return 0; + + mast.l = &l_mas; + mast.r = &r_mas; + mast.orig_l = &prev_l_mas; + mast.orig_r = &prev_r_mas; + mast.free = &mat; + mast.bn = b_node; + + while (height++ <= mas->depth) { + if (mt_slots[b_node->type] > b_node->b_end) { + mas_split_final_node(&mast, mas, height); + break; + } + + l_mas = r_mas = *mas; + l_mas.node = mas_new_ma_node(mas, b_node); + r_mas.node = mas_new_ma_node(mas, b_node); + /* + * Another way that 'jitter' is avoided is to terminate a split up early if the + * left or right node has space to spare. This is referred to as "pushing left" + * or "pushing right" and is similar to the B* tree, except the nodes left or + * right can rarely be reused due to RCU, but the ripple upwards is halted which + * is a significant savings. + */ + /* Try to push left. */ + if (mas_push_data(mas, height, &mast, true)) + break; + + /* Try to push right. */ + if (mas_push_data(mas, height, &mast, false)) + break; + + split = mab_calc_split(mas, b_node, &mid_split, prev_l_mas.min); + mast_split_data(&mast, mas, split); + /* + * Usually correct, mab_mas_cp in the above call overwrites + * r->max. + */ + mast.r->max = mas->max; + mast_fill_bnode(&mast, mas, 1); + prev_l_mas = *mast.l; + prev_r_mas = *mast.r; + } + + /* Set the original node as dead */ + mat_add(mast.free, mas->node); + mas->node = l_mas.node; + mas_wmb_replace(mas, mast.free, NULL); + mtree_range_walk(mas); + return 1; +} + +/* + * mas_reuse_node() - Reuse the node to store the data. + * @wr_mas: The maple write state + * @bn: The maple big node + * @end: The end of the data. + * + * Will always return false in RCU mode. + * + * Return: True if node was reused, false otherwise. + */ +static inline bool mas_reuse_node(struct ma_wr_state *wr_mas, + struct maple_big_node *bn, unsigned char end) +{ + /* Need to be rcu safe. */ + if (mt_in_rcu(wr_mas->mas->tree)) + return false; + + if (end > bn->b_end) { + int clear = mt_slots[wr_mas->type] - bn->b_end; + + memset(wr_mas->slots + bn->b_end, 0, sizeof(void *) * clear--); + memset(wr_mas->pivots + bn->b_end, 0, sizeof(void *) * clear); + } + mab_mas_cp(bn, 0, bn->b_end, wr_mas->mas, false); + return true; +} + +/* + * mas_commit_b_node() - Commit the big node into the tree. + * @wr_mas: The maple write state + * @b_node: The maple big node + * @end: The end of the data. + */ +static inline int mas_commit_b_node(struct ma_wr_state *wr_mas, + struct maple_big_node *b_node, unsigned char end) +{ + struct maple_node *node; + unsigned char b_end = b_node->b_end; + enum maple_type b_type = b_node->type; + + if ((b_end < mt_min_slots[b_type]) && + (!mte_is_root(wr_mas->mas->node)) && + (mas_mt_height(wr_mas->mas) > 1)) + return mas_rebalance(wr_mas->mas, b_node); + + if (b_end >= mt_slots[b_type]) + return mas_split(wr_mas->mas, b_node); + + if (mas_reuse_node(wr_mas, b_node, end)) + goto reuse_node; + + mas_node_count(wr_mas->mas, 1); + if (mas_is_err(wr_mas->mas)) + return 0; + + node = mas_pop_node(wr_mas->mas); + node->parent = mas_mn(wr_mas->mas)->parent; + wr_mas->mas->node = mt_mk_node(node, b_type); + mab_mas_cp(b_node, 0, b_end, wr_mas->mas, true); + + mas_replace(wr_mas->mas, false); +reuse_node: + mas_update_gap(wr_mas->mas); + return 1; +} + +/* + * mas_root_expand() - Expand a root to a node + * @mas: The maple state + * @entry: The entry to store into the tree + */ +static inline int mas_root_expand(struct ma_state *mas, void *entry) +{ + void *contents = mas_root_locked(mas); + enum maple_type type = maple_leaf_64; + struct maple_node *node; + void __rcu **slots; + unsigned long *pivots; + int slot = 0; + + mas_node_count(mas, 1); + if (unlikely(mas_is_err(mas))) + return 0; + + node = mas_pop_node(mas); + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + node->parent = ma_parent_ptr( + ((unsigned long)mas->tree | MA_ROOT_PARENT)); + mas->node = mt_mk_node(node, type); + + if (mas->index) { + if (contents) { + rcu_assign_pointer(slots[slot], contents); + if (likely(mas->index > 1)) + slot++; + } + pivots[slot++] = mas->index - 1; + } + + rcu_assign_pointer(slots[slot], entry); + mas->offset = slot; + pivots[slot] = mas->last; + if (mas->last != ULONG_MAX) + slot++; + mas->depth = 1; + mas_set_height(mas); + + /* swap the new root into the tree */ + rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node)); + ma_set_meta(node, maple_leaf_64, 0, slot); + return slot; +} + +static inline void mas_store_root(struct ma_state *mas, void *entry) +{ + if (likely((mas->last != 0) || (mas->index != 0))) + mas_root_expand(mas, entry); + else if (((unsigned long) (entry) & 3) == 2) + mas_root_expand(mas, entry); + else { + rcu_assign_pointer(mas->tree->ma_root, entry); + mas->node = MAS_START; + } +} + +/* + * mas_is_span_wr() - Check if the write needs to be treated as a write that + * spans the node. + * @mas: The maple state + * @piv: The pivot value being written + * @type: The maple node type + * @entry: The data to write + * + * Spanning writes are writes that start in one node and end in another OR if + * the write of a %NULL will cause the node to end with a %NULL. + * + * Return: True if this is a spanning write, false otherwise. + */ +static bool mas_is_span_wr(struct ma_wr_state *wr_mas) +{ + unsigned long max; + unsigned long last = wr_mas->mas->last; + unsigned long piv = wr_mas->r_max; + enum maple_type type = wr_mas->type; + void *entry = wr_mas->entry; + + /* Contained in this pivot */ + if (piv > last) + return false; + + max = wr_mas->mas->max; + if (unlikely(ma_is_leaf(type))) { + /* Fits in the node, but may span slots. */ + if (last < max) + return false; + + /* Writes to the end of the node but not null. */ + if ((last == max) && entry) + return false; + + /* + * Writing ULONG_MAX is not a spanning write regardless of the + * value being written as long as the range fits in the node. + */ + if ((last == ULONG_MAX) && (last == max)) + return false; + } else if (piv == last) { + if (entry) + return false; + + /* Detect spanning store wr walk */ + if (last == ULONG_MAX) + return false; + } + + trace_ma_write(__func__, wr_mas->mas, piv, entry); + + return true; +} + +static inline void mas_wr_walk_descend(struct ma_wr_state *wr_mas) +{ + wr_mas->mas->depth++; + wr_mas->type = mte_node_type(wr_mas->mas->node); + mas_wr_node_walk(wr_mas); + wr_mas->slots = ma_slots(wr_mas->node, wr_mas->type); +} + +static inline void mas_wr_walk_traverse(struct ma_wr_state *wr_mas) +{ + wr_mas->mas->max = wr_mas->r_max; + wr_mas->mas->min = wr_mas->r_min; + wr_mas->mas->node = wr_mas->content; + wr_mas->mas->offset = 0; +} +/* + * mas_wr_walk() - Walk the tree for a write. + * @wr_mas: The maple write state + * + * Uses mas_slot_locked() and does not need to worry about dead nodes. + * + * Return: True if it's contained in a node, false on spanning write. + */ +static bool mas_wr_walk(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + + while (true) { + mas_wr_walk_descend(wr_mas); + if (unlikely(mas_is_span_wr(wr_mas))) + return false; + + wr_mas->content = mas_slot_locked(mas, wr_mas->slots, + mas->offset); + if (ma_is_leaf(wr_mas->type)) + return true; + + mas_wr_walk_traverse(wr_mas); + } + + return true; +} + +static bool mas_wr_walk_index(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + + while (true) { + mas_wr_walk_descend(wr_mas); + wr_mas->content = mas_slot_locked(mas, wr_mas->slots, + mas->offset); + if (ma_is_leaf(wr_mas->type)) + return true; + mas_wr_walk_traverse(wr_mas); + + } + return true; +} +/* + * mas_extend_spanning_null() - Extend a store of a %NULL to include surrounding %NULLs. + * @l_wr_mas: The left maple write state + * @r_wr_mas: The right maple write state + */ +static inline void mas_extend_spanning_null(struct ma_wr_state *l_wr_mas, + struct ma_wr_state *r_wr_mas) +{ + struct ma_state *r_mas = r_wr_mas->mas; + struct ma_state *l_mas = l_wr_mas->mas; + unsigned char l_slot; + + l_slot = l_mas->offset; + if (!l_wr_mas->content) + l_mas->index = l_wr_mas->r_min; + + if ((l_mas->index == l_wr_mas->r_min) && + (l_slot && + !mas_slot_locked(l_mas, l_wr_mas->slots, l_slot - 1))) { + if (l_slot > 1) + l_mas->index = l_wr_mas->pivots[l_slot - 2] + 1; + else + l_mas->index = l_mas->min; + + l_mas->offset = l_slot - 1; + } + + if (!r_wr_mas->content) { + if (r_mas->last < r_wr_mas->r_max) + r_mas->last = r_wr_mas->r_max; + r_mas->offset++; + } else if ((r_mas->last == r_wr_mas->r_max) && + (r_mas->last < r_mas->max) && + !mas_slot_locked(r_mas, r_wr_mas->slots, r_mas->offset + 1)) { + r_mas->last = mas_safe_pivot(r_mas, r_wr_mas->pivots, + r_wr_mas->type, r_mas->offset + 1); + r_mas->offset++; + } +} + +static inline void *mas_state_walk(struct ma_state *mas) +{ + void *entry; + + entry = mas_start(mas); + if (mas_is_none(mas)) + return NULL; + + if (mas_is_ptr(mas)) + return entry; + + return mtree_range_walk(mas); +} + +/* + * mtree_lookup_walk() - Internal quick lookup that does not keep maple state up + * to date. + * + * @mas: The maple state. + * + * Note: Leaves mas in undesirable state. + * Return: The entry for @mas->index or %NULL on dead node. + */ +static inline void *mtree_lookup_walk(struct ma_state *mas) +{ + unsigned long *pivots; + unsigned char offset; + struct maple_node *node; + struct maple_enode *next; + enum maple_type type; + void __rcu **slots; + unsigned char end; + unsigned long max; + + next = mas->node; + max = ULONG_MAX; + do { + offset = 0; + node = mte_to_node(next); + type = mte_node_type(next); + pivots = ma_pivots(node, type); + end = ma_data_end(node, type, pivots, max); + if (unlikely(ma_dead_node(node))) + goto dead_node; + + if (pivots[offset] >= mas->index) + goto next; + + do { + offset++; + } while ((offset < end) && (pivots[offset] < mas->index)); + + if (likely(offset > end)) + max = pivots[offset]; + +next: + slots = ma_slots(node, type); + next = mt_slot(mas->tree, slots, offset); + if (unlikely(ma_dead_node(node))) + goto dead_node; + } while (!ma_is_leaf(type)); + + return (void *) next; + +dead_node: + mas_reset(mas); + return NULL; +} + +/* + * mas_new_root() - Create a new root node that only contains the entry passed + * in. + * @mas: The maple state + * @entry: The entry to store. + * + * Only valid when the index == 0 and the last == ULONG_MAX + * + * Return 0 on error, 1 on success. + */ +static inline int mas_new_root(struct ma_state *mas, void *entry) +{ + struct maple_enode *root = mas_root_locked(mas); + enum maple_type type = maple_leaf_64; + struct maple_node *node; + void __rcu **slots; + unsigned long *pivots; + + if (!entry && !mas->index && mas->last == ULONG_MAX) { + mas->depth = 0; + mas_set_height(mas); + rcu_assign_pointer(mas->tree->ma_root, entry); + mas->node = MAS_START; + goto done; + } + + mas_node_count(mas, 1); + if (mas_is_err(mas)) + return 0; + + node = mas_pop_node(mas); + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + node->parent = ma_parent_ptr( + ((unsigned long)mas->tree | MA_ROOT_PARENT)); + mas->node = mt_mk_node(node, type); + rcu_assign_pointer(slots[0], entry); + pivots[0] = mas->last; + mas->depth = 1; + mas_set_height(mas); + rcu_assign_pointer(mas->tree->ma_root, mte_mk_root(mas->node)); + +done: + if (xa_is_node(root)) + mte_destroy_walk(root, mas->tree); + + return 1; +} +/* + * mas_wr_spanning_store() - Create a subtree with the store operation completed + * and new nodes where necessary, then place the sub-tree in the actual tree. + * Note that mas is expected to point to the node which caused the store to + * span. + * @wr_mas: The maple write state + * + * Return: 0 on error, positive on success. + */ +static inline int mas_wr_spanning_store(struct ma_wr_state *wr_mas) +{ + struct maple_subtree_state mast; + struct maple_big_node b_node; + struct ma_state *mas; + unsigned char height; + + /* Left and Right side of spanning store */ + MA_STATE(l_mas, NULL, 0, 0); + MA_STATE(r_mas, NULL, 0, 0); + + MA_WR_STATE(r_wr_mas, &r_mas, wr_mas->entry); + MA_WR_STATE(l_wr_mas, &l_mas, wr_mas->entry); + + /* + * A store operation that spans multiple nodes is called a spanning + * store and is handled early in the store call stack by the function + * mas_is_span_wr(). When a spanning store is identified, the maple + * state is duplicated. The first maple state walks the left tree path + * to ``index``, the duplicate walks the right tree path to ``last``. + * The data in the two nodes are combined into a single node, two nodes, + * or possibly three nodes (see the 3-way split above). A ``NULL`` + * written to the last entry of a node is considered a spanning store as + * a rebalance is required for the operation to complete and an overflow + * of data may happen. + */ + mas = wr_mas->mas; + trace_ma_op(__func__, mas); + + if (unlikely(!mas->index && mas->last == ULONG_MAX)) + return mas_new_root(mas, wr_mas->entry); + /* + * Node rebalancing may occur due to this store, so there may be three new + * entries per level plus a new root. + */ + height = mas_mt_height(mas); + mas_node_count(mas, 1 + height * 3); + if (mas_is_err(mas)) + return 0; + + /* + * Set up right side. Need to get to the next offset after the spanning + * store to ensure it's not NULL and to combine both the next node and + * the node with the start together. + */ + r_mas = *mas; + /* Avoid overflow, walk to next slot in the tree. */ + if (r_mas.last + 1) + r_mas.last++; + + r_mas.index = r_mas.last; + mas_wr_walk_index(&r_wr_mas); + r_mas.last = r_mas.index = mas->last; + + /* Set up left side. */ + l_mas = *mas; + mas_wr_walk_index(&l_wr_mas); + + if (!wr_mas->entry) { + mas_extend_spanning_null(&l_wr_mas, &r_wr_mas); + mas->offset = l_mas.offset; + mas->index = l_mas.index; + mas->last = l_mas.last = r_mas.last; + } + + /* expanding NULLs may make this cover the entire range */ + if (!l_mas.index && r_mas.last == ULONG_MAX) { + mas_set_range(mas, 0, ULONG_MAX); + return mas_new_root(mas, wr_mas->entry); + } + + memset(&b_node, 0, sizeof(struct maple_big_node)); + /* Copy l_mas and store the value in b_node. */ + mas_store_b_node(&l_wr_mas, &b_node, l_wr_mas.node_end); + /* Copy r_mas into b_node. */ + if (r_mas.offset <= r_wr_mas.node_end) + mas_mab_cp(&r_mas, r_mas.offset, r_wr_mas.node_end, + &b_node, b_node.b_end + 1); + else + b_node.b_end++; + + /* Stop spanning searches by searching for just index. */ + l_mas.index = l_mas.last = mas->index; + + mast.bn = &b_node; + mast.orig_l = &l_mas; + mast.orig_r = &r_mas; + /* Combine l_mas and r_mas and split them up evenly again. */ + return mas_spanning_rebalance(mas, &mast, height + 1); +} + +/* + * mas_wr_node_store() - Attempt to store the value in a node + * @wr_mas: The maple write state + * + * Attempts to reuse the node, but may allocate. + * + * Return: True if stored, false otherwise + */ +static inline bool mas_wr_node_store(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + void __rcu **dst_slots; + unsigned long *dst_pivots; + unsigned char dst_offset; + unsigned char new_end = wr_mas->node_end; + unsigned char offset; + unsigned char node_slots = mt_slots[wr_mas->type]; + struct maple_node reuse, *newnode; + unsigned char copy_size, max_piv = mt_pivots[wr_mas->type]; + bool in_rcu = mt_in_rcu(mas->tree); + + offset = mas->offset; + if (mas->last == wr_mas->r_max) { + /* runs right to the end of the node */ + if (mas->last == mas->max) + new_end = offset; + /* don't copy this offset */ + wr_mas->offset_end++; + } else if (mas->last < wr_mas->r_max) { + /* new range ends in this range */ + if (unlikely(wr_mas->r_max == ULONG_MAX)) + mas_bulk_rebalance(mas, wr_mas->node_end, wr_mas->type); + + new_end++; + } else { + if (wr_mas->end_piv == mas->last) + wr_mas->offset_end++; + + new_end -= wr_mas->offset_end - offset - 1; + } + + /* new range starts within a range */ + if (wr_mas->r_min < mas->index) + new_end++; + + /* Not enough room */ + if (new_end >= node_slots) + return false; + + /* Not enough data. */ + if (!mte_is_root(mas->node) && (new_end <= mt_min_slots[wr_mas->type]) && + !(mas->mas_flags & MA_STATE_BULK)) + return false; + + /* set up node. */ + if (in_rcu) { + mas_node_count(mas, 1); + if (mas_is_err(mas)) + return false; + + newnode = mas_pop_node(mas); + } else { + memset(&reuse, 0, sizeof(struct maple_node)); + newnode = &reuse; + } + + newnode->parent = mas_mn(mas)->parent; + dst_pivots = ma_pivots(newnode, wr_mas->type); + dst_slots = ma_slots(newnode, wr_mas->type); + /* Copy from start to insert point */ + memcpy(dst_pivots, wr_mas->pivots, sizeof(unsigned long) * (offset + 1)); + memcpy(dst_slots, wr_mas->slots, sizeof(void *) * (offset + 1)); + dst_offset = offset; + + /* Handle insert of new range starting after old range */ + if (wr_mas->r_min < mas->index) { + mas->offset++; + rcu_assign_pointer(dst_slots[dst_offset], wr_mas->content); + dst_pivots[dst_offset++] = mas->index - 1; + } + + /* Store the new entry and range end. */ + if (dst_offset < max_piv) + dst_pivots[dst_offset] = mas->last; + mas->offset = dst_offset; + rcu_assign_pointer(dst_slots[dst_offset], wr_mas->entry); + + /* + * this range wrote to the end of the node or it overwrote the rest of + * the data + */ + if (wr_mas->offset_end > wr_mas->node_end || mas->last >= mas->max) { + new_end = dst_offset; + goto done; + } + + dst_offset++; + /* Copy to the end of node if necessary. */ + copy_size = wr_mas->node_end - wr_mas->offset_end + 1; + memcpy(dst_slots + dst_offset, wr_mas->slots + wr_mas->offset_end, + sizeof(void *) * copy_size); + if (dst_offset < max_piv) { + if (copy_size > max_piv - dst_offset) + copy_size = max_piv - dst_offset; + + memcpy(dst_pivots + dst_offset, + wr_mas->pivots + wr_mas->offset_end, + sizeof(unsigned long) * copy_size); + } + + if ((wr_mas->node_end == node_slots - 1) && (new_end < node_slots - 1)) + dst_pivots[new_end] = mas->max; + +done: + mas_leaf_set_meta(mas, newnode, dst_pivots, maple_leaf_64, new_end); + if (in_rcu) { + mas->node = mt_mk_node(newnode, wr_mas->type); + mas_replace(mas, false); + } else { + memcpy(wr_mas->node, newnode, sizeof(struct maple_node)); + } + trace_ma_write(__func__, mas, 0, wr_mas->entry); + mas_update_gap(mas); + return true; +} + +/* + * mas_wr_slot_store: Attempt to store a value in a slot. + * @wr_mas: the maple write state + * + * Return: True if stored, false otherwise + */ +static inline bool mas_wr_slot_store(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + unsigned long lmax; /* Logical max. */ + unsigned char offset = mas->offset; + + if ((wr_mas->r_max > mas->last) && ((wr_mas->r_min != mas->index) || + (offset != wr_mas->node_end))) + return false; + + if (offset == wr_mas->node_end - 1) + lmax = mas->max; + else + lmax = wr_mas->pivots[offset + 1]; + + /* going to overwrite too many slots. */ + if (lmax < mas->last) + return false; + + if (wr_mas->r_min == mas->index) { + /* overwriting two or more ranges with one. */ + if (lmax == mas->last) + return false; + + /* Overwriting all of offset and a portion of offset + 1. */ + rcu_assign_pointer(wr_mas->slots[offset], wr_mas->entry); + wr_mas->pivots[offset] = mas->last; + goto done; + } + + /* Doesn't end on the next range end. */ + if (lmax != mas->last) + return false; + + /* Overwriting a portion of offset and all of offset + 1 */ + if ((offset + 1 < mt_pivots[wr_mas->type]) && + (wr_mas->entry || wr_mas->pivots[offset + 1])) + wr_mas->pivots[offset + 1] = mas->last; + + rcu_assign_pointer(wr_mas->slots[offset + 1], wr_mas->entry); + wr_mas->pivots[offset] = mas->index - 1; + mas->offset++; /* Keep mas accurate. */ + +done: + trace_ma_write(__func__, mas, 0, wr_mas->entry); + mas_update_gap(mas); + return true; +} + +static inline void mas_wr_end_piv(struct ma_wr_state *wr_mas) +{ + while ((wr_mas->mas->last > wr_mas->end_piv) && + (wr_mas->offset_end < wr_mas->node_end)) + wr_mas->end_piv = wr_mas->pivots[++wr_mas->offset_end]; + + if (wr_mas->mas->last > wr_mas->end_piv) + wr_mas->end_piv = wr_mas->mas->max; +} + +static inline void mas_wr_extend_null(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + + if (mas->last < wr_mas->end_piv && !wr_mas->slots[wr_mas->offset_end]) + mas->last = wr_mas->end_piv; + + /* Check next slot(s) if we are overwriting the end */ + if ((mas->last == wr_mas->end_piv) && + (wr_mas->node_end != wr_mas->offset_end) && + !wr_mas->slots[wr_mas->offset_end + 1]) { + wr_mas->offset_end++; + if (wr_mas->offset_end == wr_mas->node_end) + mas->last = mas->max; + else + mas->last = wr_mas->pivots[wr_mas->offset_end]; + wr_mas->end_piv = mas->last; + } + + if (!wr_mas->content) { + /* If this one is null, the next and prev are not */ + mas->index = wr_mas->r_min; + } else { + /* Check prev slot if we are overwriting the start */ + if (mas->index == wr_mas->r_min && mas->offset && + !wr_mas->slots[mas->offset - 1]) { + mas->offset--; + wr_mas->r_min = mas->index = + mas_safe_min(mas, wr_mas->pivots, mas->offset); + wr_mas->r_max = wr_mas->pivots[mas->offset]; + } + } +} + +static inline bool mas_wr_append(struct ma_wr_state *wr_mas) +{ + unsigned char end = wr_mas->node_end; + unsigned char new_end = end + 1; + struct ma_state *mas = wr_mas->mas; + unsigned char node_pivots = mt_pivots[wr_mas->type]; + + if ((mas->index != wr_mas->r_min) && (mas->last == wr_mas->r_max)) { + if (new_end < node_pivots) + wr_mas->pivots[new_end] = wr_mas->pivots[end]; + + if (new_end < node_pivots) + ma_set_meta(wr_mas->node, maple_leaf_64, 0, new_end); + + rcu_assign_pointer(wr_mas->slots[new_end], wr_mas->entry); + mas->offset = new_end; + wr_mas->pivots[end] = mas->index - 1; + + return true; + } + + if ((mas->index == wr_mas->r_min) && (mas->last < wr_mas->r_max)) { + if (new_end < node_pivots) + wr_mas->pivots[new_end] = wr_mas->pivots[end]; + + rcu_assign_pointer(wr_mas->slots[new_end], wr_mas->content); + if (new_end < node_pivots) + ma_set_meta(wr_mas->node, maple_leaf_64, 0, new_end); + + wr_mas->pivots[end] = mas->last; + rcu_assign_pointer(wr_mas->slots[end], wr_mas->entry); + return true; + } + + return false; +} + +/* + * mas_wr_bnode() - Slow path for a modification. + * @wr_mas: The write maple state + * + * This is where split, rebalance end up. + */ +static void mas_wr_bnode(struct ma_wr_state *wr_mas) +{ + struct maple_big_node b_node; + + trace_ma_write(__func__, wr_mas->mas, 0, wr_mas->entry); + memset(&b_node, 0, sizeof(struct maple_big_node)); + mas_store_b_node(wr_mas, &b_node, wr_mas->offset_end); + mas_commit_b_node(wr_mas, &b_node, wr_mas->node_end); +} + +static inline void mas_wr_modify(struct ma_wr_state *wr_mas) +{ + unsigned char node_slots; + unsigned char node_size; + struct ma_state *mas = wr_mas->mas; + + /* Direct replacement */ + if (wr_mas->r_min == mas->index && wr_mas->r_max == mas->last) { + rcu_assign_pointer(wr_mas->slots[mas->offset], wr_mas->entry); + if (!!wr_mas->entry ^ !!wr_mas->content) + mas_update_gap(mas); + return; + } + + /* Attempt to append */ + node_slots = mt_slots[wr_mas->type]; + node_size = wr_mas->node_end - wr_mas->offset_end + mas->offset + 2; + if (mas->max == ULONG_MAX) + node_size++; + + /* slot and node store will not fit, go to the slow path */ + if (unlikely(node_size >= node_slots)) + goto slow_path; + + if (wr_mas->entry && (wr_mas->node_end < node_slots - 1) && + (mas->offset == wr_mas->node_end) && mas_wr_append(wr_mas)) { + if (!wr_mas->content || !wr_mas->entry) + mas_update_gap(mas); + return; + } + + if ((wr_mas->offset_end - mas->offset <= 1) && mas_wr_slot_store(wr_mas)) + return; + else if (mas_wr_node_store(wr_mas)) + return; + + if (mas_is_err(mas)) + return; + +slow_path: + mas_wr_bnode(wr_mas); +} + +/* + * mas_wr_store_entry() - Internal call to store a value + * @mas: The maple state + * @entry: The entry to store. + * + * Return: The contents that was stored at the index. + */ +static inline void *mas_wr_store_entry(struct ma_wr_state *wr_mas) +{ + struct ma_state *mas = wr_mas->mas; + + wr_mas->content = mas_start(mas); + if (mas_is_none(mas) || mas_is_ptr(mas)) { + mas_store_root(mas, wr_mas->entry); + return wr_mas->content; + } + + if (unlikely(!mas_wr_walk(wr_mas))) { + mas_wr_spanning_store(wr_mas); + return wr_mas->content; + } + + /* At this point, we are at the leaf node that needs to be altered. */ + wr_mas->end_piv = wr_mas->r_max; + mas_wr_end_piv(wr_mas); + + if (!wr_mas->entry) + mas_wr_extend_null(wr_mas); + + /* New root for a single pointer */ + if (unlikely(!mas->index && mas->last == ULONG_MAX)) { + mas_new_root(mas, wr_mas->entry); + return wr_mas->content; + } + + mas_wr_modify(wr_mas); + return wr_mas->content; +} + +/** + * mas_insert() - Internal call to insert a value + * @mas: The maple state + * @entry: The entry to store + * + * Return: %NULL or the contents that already exists at the requested index + * otherwise. The maple state needs to be checked for error conditions. + */ +static inline void *mas_insert(struct ma_state *mas, void *entry) +{ + MA_WR_STATE(wr_mas, mas, entry); + + /* + * Inserting a new range inserts either 0, 1, or 2 pivots within the + * tree. If the insert fits exactly into an existing gap with a value + * of NULL, then the slot only needs to be written with the new value. + * If the range being inserted is adjacent to another range, then only a + * single pivot needs to be inserted (as well as writing the entry). If + * the new range is within a gap but does not touch any other ranges, + * then two pivots need to be inserted: the start - 1, and the end. As + * usual, the entry must be written. Most operations require a new node + * to be allocated and replace an existing node to ensure RCU safety, + * when in RCU mode. The exception to requiring a newly allocated node + * is when inserting at the end of a node (appending). When done + * carefully, appending can reuse the node in place. + */ + wr_mas.content = mas_start(mas); + if (wr_mas.content) + goto exists; + + if (mas_is_none(mas) || mas_is_ptr(mas)) { + mas_store_root(mas, entry); + return NULL; + } + + /* spanning writes always overwrite something */ + if (!mas_wr_walk(&wr_mas)) + goto exists; + + /* At this point, we are at the leaf node that needs to be altered. */ + wr_mas.offset_end = mas->offset; + wr_mas.end_piv = wr_mas.r_max; + + if (wr_mas.content || (mas->last > wr_mas.r_max)) + goto exists; + + if (!entry) + return NULL; + + mas_wr_modify(&wr_mas); + return wr_mas.content; + +exists: + mas_set_err(mas, -EEXIST); + return wr_mas.content; + +} + +/* + * mas_prev_node() - Find the prev non-null entry at the same level in the + * tree. The prev value will be mas->node[mas->offset] or MAS_NONE. + * @mas: The maple state + * @min: The lower limit to search + * + * The prev node value will be mas->node[mas->offset] or MAS_NONE. + * Return: 1 if the node is dead, 0 otherwise. + */ +static inline int mas_prev_node(struct ma_state *mas, unsigned long min) +{ + enum maple_type mt; + int offset, level; + void __rcu **slots; + struct maple_node *node; + struct maple_enode *enode; + unsigned long *pivots; + + if (mas_is_none(mas)) + return 0; + + level = 0; + do { + node = mas_mn(mas); + if (ma_is_root(node)) + goto no_entry; + + /* Walk up. */ + if (unlikely(mas_ascend(mas))) + return 1; + offset = mas->offset; + level++; + } while (!offset); + + offset--; + mt = mte_node_type(mas->node); + node = mas_mn(mas); + slots = ma_slots(node, mt); + pivots = ma_pivots(node, mt); + mas->max = pivots[offset]; + if (offset) + mas->min = pivots[offset - 1] + 1; + if (unlikely(ma_dead_node(node))) + return 1; + + if (mas->max < min) + goto no_entry_min; + + while (level > 1) { + level--; + enode = mas_slot(mas, slots, offset); + if (unlikely(ma_dead_node(node))) + return 1; + + mas->node = enode; + mt = mte_node_type(mas->node); + node = mas_mn(mas); + slots = ma_slots(node, mt); + pivots = ma_pivots(node, mt); + offset = ma_data_end(node, mt, pivots, mas->max); + if (offset) + mas->min = pivots[offset - 1] + 1; + + if (offset < mt_pivots[mt]) + mas->max = pivots[offset]; + + if (mas->max < min) + goto no_entry; + } + + mas->node = mas_slot(mas, slots, offset); + if (unlikely(ma_dead_node(node))) + return 1; + + mas->offset = mas_data_end(mas); + if (unlikely(mte_dead_node(mas->node))) + return 1; + + return 0; + +no_entry_min: + mas->offset = offset; + if (offset) + mas->min = pivots[offset - 1] + 1; +no_entry: + if (unlikely(ma_dead_node(node))) + return 1; + + mas->node = MAS_NONE; + return 0; +} + +/* + * mas_next_node() - Get the next node at the same level in the tree. + * @mas: The maple state + * @max: The maximum pivot value to check. + * + * The next value will be mas->node[mas->offset] or MAS_NONE. + * Return: 1 on dead node, 0 otherwise. + */ +static inline int mas_next_node(struct ma_state *mas, struct maple_node *node, + unsigned long max) +{ + unsigned long min, pivot; + unsigned long *pivots; + struct maple_enode *enode; + int level = 0; + unsigned char offset; + enum maple_type mt; + void __rcu **slots; + + if (mas->max >= max) + goto no_entry; + + level = 0; + do { + if (ma_is_root(node)) + goto no_entry; + + min = mas->max + 1; + if (min > max) + goto no_entry; + + if (unlikely(mas_ascend(mas))) + return 1; + + offset = mas->offset; + level++; + node = mas_mn(mas); + mt = mte_node_type(mas->node); + pivots = ma_pivots(node, mt); + } while (unlikely(offset == ma_data_end(node, mt, pivots, mas->max))); + + slots = ma_slots(node, mt); + pivot = mas_safe_pivot(mas, pivots, ++offset, mt); + while (unlikely(level > 1)) { + /* Descend, if necessary */ + enode = mas_slot(mas, slots, offset); + if (unlikely(ma_dead_node(node))) + return 1; + + mas->node = enode; + level--; + node = mas_mn(mas); + mt = mte_node_type(mas->node); + slots = ma_slots(node, mt); + pivots = ma_pivots(node, mt); + offset = 0; + pivot = pivots[0]; + } + + enode = mas_slot(mas, slots, offset); + if (unlikely(ma_dead_node(node))) + return 1; + + mas->node = enode; + mas->min = min; + mas->max = pivot; + return 0; + +no_entry: + if (unlikely(ma_dead_node(node))) + return 1; + + mas->node = MAS_NONE; + return 0; +} + +/* + * mas_next_nentry() - Get the next node entry + * @mas: The maple state + * @max: The maximum value to check + * @*range_start: Pointer to store the start of the range. + * + * Sets @mas->offset to the offset of the next node entry, @mas->last to the + * pivot of the entry. + * + * Return: The next entry, %NULL otherwise + */ +static inline void *mas_next_nentry(struct ma_state *mas, + struct maple_node *node, unsigned long max, enum maple_type type) +{ + unsigned char count; + unsigned long pivot; + unsigned long *pivots; + void __rcu **slots; + void *entry; + + if (mas->last == mas->max) { + mas->index = mas->max; + return NULL; + } + + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + mas->index = mas_safe_min(mas, pivots, mas->offset); + if (ma_dead_node(node)) + return NULL; + + if (mas->index > max) + return NULL; + + count = ma_data_end(node, type, pivots, mas->max); + if (mas->offset > count) + return NULL; + + while (mas->offset < count) { + pivot = pivots[mas->offset]; + entry = mas_slot(mas, slots, mas->offset); + if (ma_dead_node(node)) + return NULL; + + if (entry) + goto found; + + if (pivot >= max) + return NULL; + + mas->index = pivot + 1; + mas->offset++; + } + + if (mas->index > mas->max) { + mas->index = mas->last; + return NULL; + } + + pivot = mas_safe_pivot(mas, pivots, mas->offset, type); + entry = mas_slot(mas, slots, mas->offset); + if (ma_dead_node(node)) + return NULL; + + if (!pivot) + return NULL; + + if (!entry) + return NULL; + +found: + mas->last = pivot; + return entry; +} + +static inline void mas_rewalk(struct ma_state *mas, unsigned long index) +{ + +retry: + mas_set(mas, index); + mas_state_walk(mas); + if (mas_is_start(mas)) + goto retry; + + return; + +} + +/* + * mas_next_entry() - Internal function to get the next entry. + * @mas: The maple state + * @limit: The maximum range start. + * + * Set the @mas->node to the next entry and the range_start to + * the beginning value for the entry. Does not check beyond @limit. + * Sets @mas->index and @mas->last to the limit if it is hit. + * Restarts on dead nodes. + * + * Return: the next entry or %NULL. + */ +static inline void *mas_next_entry(struct ma_state *mas, unsigned long limit) +{ + void *entry = NULL; + struct maple_enode *prev_node; + struct maple_node *node; + unsigned char offset; + unsigned long last; + enum maple_type mt; + + last = mas->last; +retry: + offset = mas->offset; + prev_node = mas->node; + node = mas_mn(mas); + mt = mte_node_type(mas->node); + mas->offset++; + if (unlikely(mas->offset >= mt_slots[mt])) { + mas->offset = mt_slots[mt] - 1; + goto next_node; + } + + while (!mas_is_none(mas)) { + entry = mas_next_nentry(mas, node, limit, mt); + if (unlikely(ma_dead_node(node))) { + mas_rewalk(mas, last); + goto retry; + } + + if (likely(entry)) + return entry; + + if (unlikely((mas->index > limit))) + break; + +next_node: + prev_node = mas->node; + offset = mas->offset; + if (unlikely(mas_next_node(mas, node, limit))) { + mas_rewalk(mas, last); + goto retry; + } + mas->offset = 0; + node = mas_mn(mas); + mt = mte_node_type(mas->node); + } + + mas->index = mas->last = limit; + mas->offset = offset; + mas->node = prev_node; + return NULL; +} + +/* + * mas_prev_nentry() - Get the previous node entry. + * @mas: The maple state. + * @limit: The lower limit to check for a value. + * + * Return: the entry, %NULL otherwise. + */ +static inline void *mas_prev_nentry(struct ma_state *mas, unsigned long limit, + unsigned long index) +{ + unsigned long pivot, min; + unsigned char offset; + struct maple_node *mn; + enum maple_type mt; + unsigned long *pivots; + void __rcu **slots; + void *entry; + +retry: + if (!mas->offset) + return NULL; + + mn = mas_mn(mas); + mt = mte_node_type(mas->node); + offset = mas->offset - 1; + if (offset >= mt_slots[mt]) + offset = mt_slots[mt] - 1; + + slots = ma_slots(mn, mt); + pivots = ma_pivots(mn, mt); + if (offset == mt_pivots[mt]) + pivot = mas->max; + else + pivot = pivots[offset]; + + if (unlikely(ma_dead_node(mn))) { + mas_rewalk(mas, index); + goto retry; + } + + while (offset && ((!mas_slot(mas, slots, offset) && pivot >= limit) || + !pivot)) + pivot = pivots[--offset]; + + min = mas_safe_min(mas, pivots, offset); + entry = mas_slot(mas, slots, offset); + if (unlikely(ma_dead_node(mn))) { + mas_rewalk(mas, index); + goto retry; + } + + if (likely(entry)) { + mas->offset = offset; + mas->last = pivot; + mas->index = min; + } + return entry; +} + +static inline void *mas_prev_entry(struct ma_state *mas, unsigned long min) +{ + void *entry; + +retry: + while (likely(!mas_is_none(mas))) { + entry = mas_prev_nentry(mas, min, mas->index); + if (unlikely(mas->last < min)) + goto not_found; + + if (likely(entry)) + return entry; + + if (unlikely(mas_prev_node(mas, min))) { + mas_rewalk(mas, mas->index); + goto retry; + } + + mas->offset++; + } + + mas->offset--; +not_found: + mas->index = mas->last = min; + return NULL; +} + +/* + * mas_rev_awalk() - Internal function. Reverse allocation walk. Find the + * highest gap address of a given size in a given node and descend. + * @mas: The maple state + * @size: The needed size. + * + * Return: True if found in a leaf, false otherwise. + * + */ +static bool mas_rev_awalk(struct ma_state *mas, unsigned long size) +{ + enum maple_type type = mte_node_type(mas->node); + struct maple_node *node = mas_mn(mas); + unsigned long *pivots, *gaps; + void __rcu **slots; + unsigned long gap = 0; + unsigned long max, min, index; + unsigned char offset; + + if (unlikely(mas_is_err(mas))) + return true; + + if (ma_is_dense(type)) { + /* dense nodes. */ + mas->offset = (unsigned char)(mas->index - mas->min); + return true; + } + + pivots = ma_pivots(node, type); + slots = ma_slots(node, type); + gaps = ma_gaps(node, type); + offset = mas->offset; + min = mas_safe_min(mas, pivots, offset); + /* Skip out of bounds. */ + while (mas->last < min) + min = mas_safe_min(mas, pivots, --offset); + + max = mas_safe_pivot(mas, pivots, offset, type); + index = mas->index; + while (index <= max) { + gap = 0; + if (gaps) + gap = gaps[offset]; + else if (!mas_slot(mas, slots, offset)) + gap = max - min + 1; + + if (gap) { + if ((size <= gap) && (size <= mas->last - min + 1)) + break; + + if (!gaps) { + /* Skip the next slot, it cannot be a gap. */ + if (offset < 2) + goto ascend; + + offset -= 2; + max = pivots[offset]; + min = mas_safe_min(mas, pivots, offset); + continue; + } + } + + if (!offset) + goto ascend; + + offset--; + max = min - 1; + min = mas_safe_min(mas, pivots, offset); + } + + if (unlikely(index > max)) { + mas_set_err(mas, -EBUSY); + return false; + } + + if (unlikely(ma_is_leaf(type))) { + mas->offset = offset; + mas->min = min; + mas->max = min + gap - 1; + return true; + } + + /* descend, only happens under lock. */ + mas->node = mas_slot(mas, slots, offset); + mas->min = min; + mas->max = max; + mas->offset = mas_data_end(mas); + return false; + +ascend: + if (mte_is_root(mas->node)) + mas_set_err(mas, -EBUSY); + + return false; +} + +static inline bool mas_anode_descend(struct ma_state *mas, unsigned long size) +{ + enum maple_type type = mte_node_type(mas->node); + unsigned long pivot, min, gap = 0; + unsigned char count, offset; + unsigned long *gaps = NULL, *pivots = ma_pivots(mas_mn(mas), type); + void __rcu **slots = ma_slots(mas_mn(mas), type); + bool found = false; + + if (ma_is_dense(type)) { + mas->offset = (unsigned char)(mas->index - mas->min); + return true; + } + + gaps = ma_gaps(mte_to_node(mas->node), type); + offset = mas->offset; + count = mt_slots[type]; + min = mas_safe_min(mas, pivots, offset); + for (; offset < count; offset++) { + pivot = mas_safe_pivot(mas, pivots, offset, type); + if (offset && !pivot) + break; + + /* Not within lower bounds */ + if (mas->index > pivot) + goto next_slot; + + if (gaps) + gap = gaps[offset]; + else if (!mas_slot(mas, slots, offset)) + gap = min(pivot, mas->last) - max(mas->index, min) + 1; + else + goto next_slot; + + if (gap >= size) { + if (ma_is_leaf(type)) { + found = true; + goto done; + } + if (mas->index <= pivot) { + mas->node = mas_slot(mas, slots, offset); + mas->min = min; + mas->max = pivot; + offset = 0; + type = mte_node_type(mas->node); + count = mt_slots[type]; + break; + } + } +next_slot: + min = pivot + 1; + if (mas->last <= pivot) { + mas_set_err(mas, -EBUSY); + return true; + } + } + + if (mte_is_root(mas->node)) + found = true; +done: + mas->offset = offset; + return found; +} + +/** + * mas_walk() - Search for @mas->index in the tree. + * @mas: The maple state. + * + * mas->index and mas->last will be set to the range if there is a value. If + * mas->node is MAS_NONE, reset to MAS_START. + * + * Return: the entry at the location or %NULL. + */ +void *mas_walk(struct ma_state *mas) +{ + void *entry; + +retry: + entry = mas_state_walk(mas); + if (mas_is_start(mas)) + goto retry; + + if (mas_is_ptr(mas)) { + if (!mas->index) { + mas->last = 0; + } else { + mas->index = 1; + mas->last = ULONG_MAX; + } + return entry; + } + + if (mas_is_none(mas)) { + mas->index = 0; + mas->last = ULONG_MAX; + } + + return entry; +} + +static inline bool mas_rewind_node(struct ma_state *mas) +{ + unsigned char slot; + + do { + if (mte_is_root(mas->node)) { + slot = mas->offset; + if (!slot) + return false; + } else { + mas_ascend(mas); + slot = mas->offset; + } + } while (!slot); + + mas->offset = --slot; + return true; +} + +/* + * mas_skip_node() - Internal function. Skip over a node. + * @mas: The maple state. + * + * Return: true if there is another node, false otherwise. + */ +static inline bool mas_skip_node(struct ma_state *mas) +{ + unsigned char slot, slot_count; + unsigned long *pivots; + enum maple_type mt; + + mt = mte_node_type(mas->node); + slot_count = mt_slots[mt] - 1; + do { + if (mte_is_root(mas->node)) { + slot = mas->offset; + if (slot > slot_count) { + mas_set_err(mas, -EBUSY); + return false; + } + } else { + mas_ascend(mas); + slot = mas->offset; + mt = mte_node_type(mas->node); + slot_count = mt_slots[mt] - 1; + } + } while (slot > slot_count); + + mas->offset = ++slot; + pivots = ma_pivots(mas_mn(mas), mt); + if (slot > 0) + mas->min = pivots[slot - 1] + 1; + + if (slot <= slot_count) + mas->max = pivots[slot]; + + return true; +} + +/* + * mas_awalk() - Allocation walk. Search from low address to high, for a gap of + * @size + * @mas: The maple state + * @size: The size of the gap required + * + * Search between @mas->index and @mas->last for a gap of @size. + */ +static inline void mas_awalk(struct ma_state *mas, unsigned long size) +{ + struct maple_enode *last = NULL; + + /* + * There are 4 options: + * go to child (descend) + * go back to parent (ascend) + * no gap found. (return, slot == MAPLE_NODE_SLOTS) + * found the gap. (return, slot != MAPLE_NODE_SLOTS) + */ + while (!mas_is_err(mas) && !mas_anode_descend(mas, size)) { + if (last == mas->node) + mas_skip_node(mas); + else + last = mas->node; + } +} + +/* + * mas_fill_gap() - Fill a located gap with @entry. + * @mas: The maple state + * @entry: The value to store + * @slot: The offset into the node to store the @entry + * @size: The size of the entry + * @index: The start location + */ +static inline void mas_fill_gap(struct ma_state *mas, void *entry, + unsigned char slot, unsigned long size, unsigned long *index) +{ + MA_WR_STATE(wr_mas, mas, entry); + unsigned char pslot = mte_parent_slot(mas->node); + struct maple_enode *mn = mas->node; + unsigned long *pivots; + enum maple_type ptype; + /* + * mas->index is the start address for the search + * which may no longer be needed. + * mas->last is the end address for the search + */ + + *index = mas->index; + mas->last = mas->index + size - 1; + + /* + * It is possible that using mas->max and mas->min to correctly + * calculate the index and last will cause an issue in the gap + * calculation, so fix the ma_state here + */ + mas_ascend(mas); + ptype = mte_node_type(mas->node); + pivots = ma_pivots(mas_mn(mas), ptype); + mas->max = mas_safe_pivot(mas, pivots, pslot, ptype); + mas->min = mas_safe_min(mas, pivots, pslot); + mas->node = mn; + mas->offset = slot; + mas_wr_store_entry(&wr_mas); +} + +/* + * mas_sparse_area() - Internal function. Return upper or lower limit when + * searching for a gap in an empty tree. + * @mas: The maple state + * @min: the minimum range + * @max: The maximum range + * @size: The size of the gap + * @fwd: Searching forward or back + */ +static inline void mas_sparse_area(struct ma_state *mas, unsigned long min, + unsigned long max, unsigned long size, bool fwd) +{ + unsigned long start = 0; + + if (!unlikely(mas_is_none(mas))) + start++; + /* mas_is_ptr */ + + if (start < min) + start = min; + + if (fwd) { + mas->index = start; + mas->last = start + size - 1; + return; + } + + mas->index = max; +} + +/* + * mas_empty_area() - Get the lowest address within the range that is + * sufficient for the size requested. + * @mas: The maple state + * @min: The lowest value of the range + * @max: The highest value of the range + * @size: The size needed + */ +int mas_empty_area(struct ma_state *mas, unsigned long min, + unsigned long max, unsigned long size) +{ + unsigned char offset; + unsigned long *pivots; + enum maple_type mt; + + if (mas_is_start(mas)) + mas_start(mas); + else if (mas->offset >= 2) + mas->offset -= 2; + else if (!mas_skip_node(mas)) + return -EBUSY; + + /* Empty set */ + if (mas_is_none(mas) || mas_is_ptr(mas)) { + mas_sparse_area(mas, min, max, size, true); + return 0; + } + + /* The start of the window can only be within these values */ + mas->index = min; + mas->last = max; + mas_awalk(mas, size); + + if (unlikely(mas_is_err(mas))) + return xa_err(mas->node); + + offset = mas->offset; + if (unlikely(offset == MAPLE_NODE_SLOTS)) + return -EBUSY; + + mt = mte_node_type(mas->node); + pivots = ma_pivots(mas_mn(mas), mt); + if (offset) + mas->min = pivots[offset - 1] + 1; + + if (offset < mt_pivots[mt]) + mas->max = pivots[offset]; + + if (mas->index < mas->min) + mas->index = mas->min; + + mas->last = mas->index + size - 1; + return 0; +} + +/* + * mas_empty_area_rev() - Get the highest address within the range that is + * sufficient for the size requested. + * @mas: The maple state + * @min: The lowest value of the range + * @max: The highest value of the range + * @size: The size needed + */ +int mas_empty_area_rev(struct ma_state *mas, unsigned long min, + unsigned long max, unsigned long size) +{ + struct maple_enode *last = mas->node; + + if (mas_is_start(mas)) { + mas_start(mas); + mas->offset = mas_data_end(mas); + } else if (mas->offset >= 2) { + mas->offset -= 2; + } else if (!mas_rewind_node(mas)) { + return -EBUSY; + } + + /* Empty set. */ + if (mas_is_none(mas) || mas_is_ptr(mas)) { + mas_sparse_area(mas, min, max, size, false); + return 0; + } + + /* The start of the window can only be within these values. */ + mas->index = min; + mas->last = max; + + while (!mas_rev_awalk(mas, size)) { + if (last == mas->node) { + if (!mas_rewind_node(mas)) + return -EBUSY; + } else { + last = mas->node; + } + } + + if (mas_is_err(mas)) + return xa_err(mas->node); + + if (unlikely(mas->offset == MAPLE_NODE_SLOTS)) + return -EBUSY; + + /* + * mas_rev_awalk() has set mas->min and mas->max to the gap values. If + * the maximum is outside the window we are searching, then use the last + * location in the search. + * mas->max and mas->min is the range of the gap. + * mas->index and mas->last are currently set to the search range. + */ + + /* Trim the upper limit to the max. */ + if (mas->max <= mas->last) + mas->last = mas->max; + + mas->index = mas->last - size + 1; + return 0; +} + +static inline int mas_alloc(struct ma_state *mas, void *entry, + unsigned long size, unsigned long *index) +{ + unsigned long min; + + mas_start(mas); + if (mas_is_none(mas) || mas_is_ptr(mas)) { + mas_root_expand(mas, entry); + if (mas_is_err(mas)) + return xa_err(mas->node); + + if (!mas->index) + return mte_pivot(mas->node, 0); + return mte_pivot(mas->node, 1); + } + + /* Must be walking a tree. */ + mas_awalk(mas, size); + if (mas_is_err(mas)) + return xa_err(mas->node); + + if (mas->offset == MAPLE_NODE_SLOTS) + goto no_gap; + + /* + * At this point, mas->node points to the right node and we have an + * offset that has a sufficient gap. + */ + min = mas->min; + if (mas->offset) + min = mte_pivot(mas->node, mas->offset - 1) + 1; + + if (mas->index < min) + mas->index = min; + + mas_fill_gap(mas, entry, mas->offset, size, index); + return 0; + +no_gap: + return -EBUSY; +} + +static inline int mas_rev_alloc(struct ma_state *mas, unsigned long min, + unsigned long max, void *entry, + unsigned long size, unsigned long *index) +{ + int ret = 0; + + ret = mas_empty_area_rev(mas, min, max, size); + if (ret) + return ret; + + if (mas_is_err(mas)) + return xa_err(mas->node); + + if (mas->offset == MAPLE_NODE_SLOTS) + goto no_gap; + + mas_fill_gap(mas, entry, mas->offset, size, index); + return 0; + +no_gap: + return -EBUSY; +} + +/* + * mas_dead_leaves() - Mark all leaves of a node as dead. + * @mas: The maple state + * @slots: Pointer to the slot array + * + * Must hold the write lock. + * + * Return: The number of leaves marked as dead. + */ +static inline +unsigned char mas_dead_leaves(struct ma_state *mas, void __rcu **slots) +{ + struct maple_node *node; + enum maple_type type; + void *entry; + int offset; + + for (offset = 0; offset < mt_slot_count(mas->node); offset++) { + entry = mas_slot_locked(mas, slots, offset); + type = mte_node_type(entry); + node = mte_to_node(entry); + /* Use both node and type to catch LE & BE metadata */ + if (!node || !type) + break; + + mte_set_node_dead(entry); + smp_wmb(); /* Needed for RCU */ + node->type = type; + rcu_assign_pointer(slots[offset], node); + } + + return offset; +} + +static void __rcu **mas_dead_walk(struct ma_state *mas, unsigned char offset) +{ + struct maple_node *node, *next; + void __rcu **slots = NULL; + + next = mas_mn(mas); + do { + mas->node = ma_enode_ptr(next); + node = mas_mn(mas); + slots = ma_slots(node, node->type); + next = mas_slot_locked(mas, slots, offset); + offset = 0; + } while (!ma_is_leaf(next->type)); + + return slots; +} + +static void mt_free_walk(struct rcu_head *head) +{ + void __rcu **slots; + struct maple_node *node, *start; + struct maple_tree mt; + unsigned char offset; + enum maple_type type; + MA_STATE(mas, &mt, 0, 0); + + node = container_of(head, struct maple_node, rcu); + + if (ma_is_leaf(node->type)) + goto free_leaf; + + mt_init_flags(&mt, node->ma_flags); + mas_lock(&mas); + start = node; + mas.node = mt_mk_node(node, node->type); + slots = mas_dead_walk(&mas, 0); + node = mas_mn(&mas); + do { + mt_free_bulk(node->slot_len, slots); + offset = node->parent_slot + 1; + mas.node = node->piv_parent; + if (mas_mn(&mas) == node) + goto start_slots_free; + + type = mte_node_type(mas.node); + slots = ma_slots(mte_to_node(mas.node), type); + if ((offset < mt_slots[type]) && (slots[offset])) + slots = mas_dead_walk(&mas, offset); + + node = mas_mn(&mas); + } while ((node != start) || (node->slot_len < offset)); + + slots = ma_slots(node, node->type); + mt_free_bulk(node->slot_len, slots); + +start_slots_free: + mas_unlock(&mas); +free_leaf: + mt_free_rcu(&node->rcu); +} + +static inline void __rcu **mas_destroy_descend(struct ma_state *mas, + struct maple_enode *prev, unsigned char offset) +{ + struct maple_node *node; + struct maple_enode *next = mas->node; + void __rcu **slots = NULL; + + do { + mas->node = next; + node = mas_mn(mas); + slots = ma_slots(node, mte_node_type(mas->node)); + next = mas_slot_locked(mas, slots, 0); + if ((mte_dead_node(next))) + next = mas_slot_locked(mas, slots, 1); + + mte_set_node_dead(mas->node); + node->type = mte_node_type(mas->node); + node->piv_parent = prev; + node->parent_slot = offset; + offset = 0; + prev = mas->node; + } while (!mte_is_leaf(next)); + + return slots; +} + +static void mt_destroy_walk(struct maple_enode *enode, unsigned char ma_flags, + bool free) +{ + void __rcu **slots; + struct maple_node *node = mte_to_node(enode); + struct maple_enode *start; + struct maple_tree mt; + + MA_STATE(mas, &mt, 0, 0); + + if (mte_is_leaf(enode)) + goto free_leaf; + + mt_init_flags(&mt, ma_flags); + mas_lock(&mas); + + mas.node = start = enode; + slots = mas_destroy_descend(&mas, start, 0); + node = mas_mn(&mas); + do { + enum maple_type type; + unsigned char offset; + struct maple_enode *parent, *tmp; + + node->slot_len = mas_dead_leaves(&mas, slots); + if (free) + mt_free_bulk(node->slot_len, slots); + offset = node->parent_slot + 1; + mas.node = node->piv_parent; + if (mas_mn(&mas) == node) + goto start_slots_free; + + type = mte_node_type(mas.node); + slots = ma_slots(mte_to_node(mas.node), type); + if (offset >= mt_slots[type]) + goto next; + + tmp = mas_slot_locked(&mas, slots, offset); + if (mte_node_type(tmp) && mte_to_node(tmp)) { + parent = mas.node; + mas.node = tmp; + slots = mas_destroy_descend(&mas, parent, offset); + } +next: + node = mas_mn(&mas); + } while (start != mas.node); + + node = mas_mn(&mas); + node->slot_len = mas_dead_leaves(&mas, slots); + if (free) + mt_free_bulk(node->slot_len, slots); + +start_slots_free: + mas_unlock(&mas); + +free_leaf: + if (free) + mt_free_rcu(&node->rcu); +} + +/* + * mte_destroy_walk() - Free a tree or sub-tree. + * @enode - the encoded maple node (maple_enode) to start + * @mn - the tree to free - needed for node types. + * + * Must hold the write lock. + */ +static inline void mte_destroy_walk(struct maple_enode *enode, + struct maple_tree *mt) +{ + struct maple_node *node = mte_to_node(enode); + + if (mt_in_rcu(mt)) { + mt_destroy_walk(enode, mt->ma_flags, false); + call_rcu(&node->rcu, mt_free_walk); + } else { + mt_destroy_walk(enode, mt->ma_flags, true); + } +} + +static void mas_wr_store_setup(struct ma_wr_state *wr_mas) +{ + if (!mas_is_start(wr_mas->mas)) { + if (mas_is_none(wr_mas->mas)) { + mas_reset(wr_mas->mas); + } else { + wr_mas->r_max = wr_mas->mas->max; + wr_mas->type = mte_node_type(wr_mas->mas->node); + if (mas_is_span_wr(wr_mas)) + mas_reset(wr_mas->mas); + } + } + +} + +/* Interface */ + +/** + * mas_store() - Store an @entry. + * @mas: The maple state. + * @entry: The entry to store. + * + * The @mas->index and @mas->last is used to set the range for the @entry. + * Note: The @mas should have pre-allocated entries to ensure there is memory to + * store the entry. Please see mas_expected_entries()/mas_destroy() for more details. + * + * Return: the first entry between mas->index and mas->last or %NULL. + */ +void *mas_store(struct ma_state *mas, void *entry) +{ + MA_WR_STATE(wr_mas, mas, entry); + + trace_ma_write(__func__, mas, 0, entry); +#ifdef CONFIG_DEBUG_MAPLE_TREE + if (mas->index > mas->last) + pr_err("Error %lu > %lu %p\n", mas->index, mas->last, entry); + MT_BUG_ON(mas->tree, mas->index > mas->last); + if (mas->index > mas->last) { + mas_set_err(mas, -EINVAL); + return NULL; + } + +#endif + + /* + * Storing is the same operation as insert with the added caveat that it + * can overwrite entries. Although this seems simple enough, one may + * want to examine what happens if a single store operation was to + * overwrite multiple entries within a self-balancing B-Tree. + */ + mas_wr_store_setup(&wr_mas); + mas_wr_store_entry(&wr_mas); + return wr_mas.content; +} + +/** + * mas_store_gfp() - Store a value into the tree. + * @mas: The maple state + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations if necessary. + * + * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not + * be allocated. + */ +int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp) +{ + MA_WR_STATE(wr_mas, mas, entry); + + mas_wr_store_setup(&wr_mas); + trace_ma_write(__func__, mas, 0, entry); +retry: + mas_wr_store_entry(&wr_mas); + if (unlikely(mas_nomem(mas, gfp))) + goto retry; + + if (unlikely(mas_is_err(mas))) + return xa_err(mas->node); + + return 0; +} + +/** + * mas_store_prealloc() - Store a value into the tree using memory + * preallocated in the maple state. + * @mas: The maple state + * @entry: The entry to store. + */ +void mas_store_prealloc(struct ma_state *mas, void *entry) +{ + MA_WR_STATE(wr_mas, mas, entry); + + mas_wr_store_setup(&wr_mas); + trace_ma_write(__func__, mas, 0, entry); + mas_wr_store_entry(&wr_mas); + BUG_ON(mas_is_err(mas)); + mas_destroy(mas); +} + +/** + * mas_preallocate() - Preallocate enough nodes for a store operation + * @mas: The maple state + * @entry: The entry that will be stored + * @gfp: The GFP_FLAGS to use for allocations. + * + * Return: 0 on success, -ENOMEM if memory could not be allocated. + */ +int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) +{ + int ret; + + mas_node_count_gfp(mas, 1 + mas_mt_height(mas) * 3, gfp); + mas->mas_flags |= MA_STATE_PREALLOC; + if (likely(!mas_is_err(mas))) + return 0; + + mas_set_alloc_req(mas, 0); + ret = xa_err(mas->node); + mas_reset(mas); + mas_destroy(mas); + mas_reset(mas); + return ret; +} + +/* + * mas_destroy() - destroy a maple state. + * @mas: The maple state + * + * Upon completion, check the left-most node and rebalance against the node to + * the right if necessary. Frees any allocated nodes associated with this maple + * state. + */ +void mas_destroy(struct ma_state *mas) +{ + struct maple_alloc *node; + + /* + * When using mas_for_each() to insert an expected number of elements, + * it is possible that the number inserted is less than the expected + * number. To fix an invalid final node, a check is performed here to + * rebalance the previous node with the final node. + */ + if (mas->mas_flags & MA_STATE_REBALANCE) { + unsigned char end; + + if (mas_is_start(mas)) + mas_start(mas); + + mtree_range_walk(mas); + end = mas_data_end(mas) + 1; + if (end < mt_min_slot_count(mas->node) - 1) + mas_destroy_rebalance(mas, end); + + mas->mas_flags &= ~MA_STATE_REBALANCE; + } + mas->mas_flags &= ~(MA_STATE_BULK|MA_STATE_PREALLOC); + + while (mas->alloc && !((unsigned long)mas->alloc & 0x1)) { + node = mas->alloc; + mas->alloc = node->slot[0]; + if (node->node_count > 0) + mt_free_bulk(node->node_count, + (void __rcu **)&node->slot[1]); + kmem_cache_free(maple_node_cache, node); + } + mas->alloc = NULL; +} + +/* + * mas_expected_entries() - Set the expected number of entries that will be inserted. + * @mas: The maple state + * @nr_entries: The number of expected entries. + * + * This will attempt to pre-allocate enough nodes to store the expected number + * of entries. The allocations will occur using the bulk allocator interface + * for speed. Please call mas_destroy() on the @mas after inserting the entries + * to ensure any unused nodes are freed. + * + * Return: 0 on success, -ENOMEM if memory could not be allocated. + */ +int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries) +{ + int nonleaf_cap = MAPLE_ARANGE64_SLOTS - 2; + struct maple_enode *enode = mas->node; + int nr_nodes; + int ret; + + /* + * Sometimes it is necessary to duplicate a tree to a new tree, such as + * forking a process and duplicating the VMAs from one tree to a new + * tree. When such a situation arises, it is known that the new tree is + * not going to be used until the entire tree is populated. For + * performance reasons, it is best to use a bulk load with RCU disabled. + * This allows for optimistic splitting that favours the left and reuse + * of nodes during the operation. + */ + + /* Optimize splitting for bulk insert in-order */ + mas->mas_flags |= MA_STATE_BULK; + + /* + * Avoid overflow, assume a gap between each entry and a trailing null. + * If this is wrong, it just means allocation can happen during + * insertion of entries. + */ + nr_nodes = max(nr_entries, nr_entries * 2 + 1); + if (!mt_is_alloc(mas->tree)) + nonleaf_cap = MAPLE_RANGE64_SLOTS - 2; + + /* Leaves; reduce slots to keep space for expansion */ + nr_nodes = DIV_ROUND_UP(nr_nodes, MAPLE_RANGE64_SLOTS - 2); + /* Internal nodes */ + nr_nodes += DIV_ROUND_UP(nr_nodes, nonleaf_cap); + /* Add working room for split (2 nodes) + new parents */ + mas_node_count(mas, nr_nodes + 3); + + /* Detect if allocations run out */ + mas->mas_flags |= MA_STATE_PREALLOC; + + if (!mas_is_err(mas)) + return 0; + + ret = xa_err(mas->node); + mas->node = enode; + mas_destroy(mas); + return ret; + +} + +/** + * mas_next() - Get the next entry. + * @mas: The maple state + * @max: The maximum index to check. + * + * Returns the next entry after @mas->index. + * Must hold rcu_read_lock or the write lock. + * Can return the zero entry. + * + * Return: The next entry or %NULL + */ +void *mas_next(struct ma_state *mas, unsigned long max) +{ + if (mas_is_none(mas) || mas_is_paused(mas)) + mas->node = MAS_START; + + if (mas_is_start(mas)) + mas_walk(mas); /* Retries on dead nodes handled by mas_walk */ + + if (mas_is_ptr(mas)) { + if (!mas->index) { + mas->index = 1; + mas->last = ULONG_MAX; + } + return NULL; + } + + if (mas->last == ULONG_MAX) + return NULL; + + /* Retries on dead nodes handled by mas_next_entry */ + return mas_next_entry(mas, max); +} +EXPORT_SYMBOL_GPL(mas_next); + +/** + * mt_next() - get the next value in the maple tree + * @mt: The maple tree + * @index: The start index + * @max: The maximum index to check + * + * Return: The entry at @index or higher, or %NULL if nothing is found. + */ +void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max) +{ + void *entry = NULL; + MA_STATE(mas, mt, index, index); + + rcu_read_lock(); + entry = mas_next(&mas, max); + rcu_read_unlock(); + return entry; +} +EXPORT_SYMBOL_GPL(mt_next); + +/** + * mas_prev() - Get the previous entry + * @mas: The maple state + * @min: The minimum value to check. + * + * Must hold rcu_read_lock or the write lock. + * Will reset mas to MAS_START if the node is MAS_NONE. Will stop on not + * searchable nodes. + * + * Return: the previous value or %NULL. + */ +void *mas_prev(struct ma_state *mas, unsigned long min) +{ + if (!mas->index) { + /* Nothing comes before 0 */ + mas->last = 0; + return NULL; + } + + if (unlikely(mas_is_ptr(mas))) + return NULL; + + if (mas_is_none(mas) || mas_is_paused(mas)) + mas->node = MAS_START; + + if (mas_is_start(mas)) { + mas_walk(mas); + if (!mas->index) + return NULL; + } + + if (mas_is_ptr(mas)) { + if (!mas->index) { + mas->last = 0; + return NULL; + } + + mas->index = mas->last = 0; + return mas_root_locked(mas); + } + return mas_prev_entry(mas, min); +} +EXPORT_SYMBOL_GPL(mas_prev); + +/** + * mt_prev() - get the previous value in the maple tree + * @mt: The maple tree + * @index: The start index + * @min: The minimum index to check + * + * Return: The entry at @index or lower, or %NULL if nothing is found. + */ +void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min) +{ + void *entry = NULL; + MA_STATE(mas, mt, index, index); + + rcu_read_lock(); + entry = mas_prev(&mas, min); + rcu_read_unlock(); + return entry; +} +EXPORT_SYMBOL_GPL(mt_prev); + +/** + * mas_pause() - Pause a mas_find/mas_for_each to drop the lock. + * @mas: The maple state to pause + * + * Some users need to pause a walk and drop the lock they're holding in + * order to yield to a higher priority thread or carry out an operation + * on an entry. Those users should call this function before they drop + * the lock. It resets the @mas to be suitable for the next iteration + * of the loop after the user has reacquired the lock. If most entries + * found during a walk require you to call mas_pause(), the mt_for_each() + * iterator may be more appropriate. + * + */ +void mas_pause(struct ma_state *mas) +{ + mas->node = MAS_PAUSE; +} +EXPORT_SYMBOL_GPL(mas_pause); + +/** + * mas_find() - On the first call, find the entry at or after mas->index up to + * %max. Otherwise, find the entry after mas->index. + * @mas: The maple state + * @max: The maximum value to check. + * + * Must hold rcu_read_lock or the write lock. + * If an entry exists, last and index are updated accordingly. + * May set @mas->node to MAS_NONE. + * + * Return: The entry or %NULL. + */ +void *mas_find(struct ma_state *mas, unsigned long max) +{ + if (unlikely(mas_is_paused(mas))) { + if (unlikely(mas->last == ULONG_MAX)) { + mas->node = MAS_NONE; + return NULL; + } + mas->node = MAS_START; + mas->index = ++mas->last; + } + + if (unlikely(mas_is_start(mas))) { + /* First run or continue */ + void *entry; + + if (mas->index > max) + return NULL; + + entry = mas_walk(mas); + if (entry) + return entry; + } + + if (unlikely(!mas_searchable(mas))) + return NULL; + + /* Retries on dead nodes handled by mas_next_entry */ + return mas_next_entry(mas, max); +} + +/** + * mas_find_rev: On the first call, find the first non-null entry at or below + * mas->index down to %min. Otherwise find the first non-null entry below + * mas->index down to %min. + * @mas: The maple state + * @min: The minimum value to check. + * + * Must hold rcu_read_lock or the write lock. + * If an entry exists, last and index are updated accordingly. + * May set @mas->node to MAS_NONE. + * + * Return: The entry or %NULL. + */ +void *mas_find_rev(struct ma_state *mas, unsigned long min) +{ + if (unlikely(mas_is_paused(mas))) { + if (unlikely(mas->last == ULONG_MAX)) { + mas->node = MAS_NONE; + return NULL; + } + mas->node = MAS_START; + mas->last = --mas->index; + } + + if (unlikely(mas_is_start(mas))) { + /* First run or continue */ + void *entry; + + if (mas->index < min) + return NULL; + + entry = mas_walk(mas); + if (entry) + return entry; + } + + if (unlikely(!mas_searchable(mas))) + return NULL; + + if (mas->index < min) + return NULL; + + /* Retries on dead nodes handled by mas_next_entry */ + return mas_prev_entry(mas, min); +} +EXPORT_SYMBOL_GPL(mas_find); + +/** + * mas_erase() - Find the range in which index resides and erase the entire + * range. + * @mas: The maple state + * + * Must hold the write lock. + * Searches for @mas->index, sets @mas->index and @mas->last to the range and + * erases that range. + * + * Return: the entry that was erased or %NULL, @mas->index and @mas->last are updated. + */ +void *mas_erase(struct ma_state *mas) +{ + void *entry; + MA_WR_STATE(wr_mas, mas, NULL); + + if (mas_is_none(mas) || mas_is_paused(mas)) + mas->node = MAS_START; + + /* Retry unnecessary when holding the write lock. */ + entry = mas_state_walk(mas); + if (!entry) + return NULL; + +write_retry: + /* Must reset to ensure spanning writes of last slot are detected */ + mas_reset(mas); + mas_wr_store_setup(&wr_mas); + mas_wr_store_entry(&wr_mas); + if (mas_nomem(mas, GFP_KERNEL)) + goto write_retry; + + return entry; +} +EXPORT_SYMBOL_GPL(mas_erase); + +/** + * mas_nomem() - Check if there was an error allocating and do the allocation + * if necessary If there are allocations, then free them. + * @mas: The maple state + * @gfp: The GFP_FLAGS to use for allocations + * Return: true on allocation, false otherwise. + */ +bool mas_nomem(struct ma_state *mas, gfp_t gfp) + __must_hold(mas->tree->lock) +{ + if (likely(mas->node != MA_ERROR(-ENOMEM))) { + mas_destroy(mas); + return false; + } + + if (gfpflags_allow_blocking(gfp) && !mt_external_lock(mas->tree)) { + mtree_unlock(mas->tree); + mas_alloc_nodes(mas, gfp); + mtree_lock(mas->tree); + } else { + mas_alloc_nodes(mas, gfp); + } + + if (!mas_allocated(mas)) + return false; + + mas->node = MAS_START; + return true; +} + +void __init maple_tree_init(void) +{ + maple_node_cache = kmem_cache_create("maple_node", + sizeof(struct maple_node), sizeof(struct maple_node), + SLAB_PANIC, NULL); +} + +/** + * mtree_load() - Load a value stored in a maple tree + * @mt: The maple tree + * @index: The index to load + * + * Return: the entry or %NULL + */ +void *mtree_load(struct maple_tree *mt, unsigned long index) +{ + MA_STATE(mas, mt, index, index); + void *entry; + + trace_ma_read(__func__, &mas); + rcu_read_lock(); +retry: + entry = mas_start(&mas); + if (unlikely(mas_is_none(&mas))) + goto unlock; + + if (unlikely(mas_is_ptr(&mas))) { + if (index) + entry = NULL; + + goto unlock; + } + + entry = mtree_lookup_walk(&mas); + if (!entry && unlikely(mas_is_start(&mas))) + goto retry; +unlock: + rcu_read_unlock(); + if (xa_is_zero(entry)) + return NULL; + + return entry; +} +EXPORT_SYMBOL(mtree_load); + +/** + * mtree_store_range() - Store an entry at a given range. + * @mt: The maple tree + * @index: The start of the range + * @last: The end of the range + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations + * + * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not + * be allocated. + */ +int mtree_store_range(struct maple_tree *mt, unsigned long index, + unsigned long last, void *entry, gfp_t gfp) +{ + MA_STATE(mas, mt, index, last); + MA_WR_STATE(wr_mas, &mas, entry); + + trace_ma_write(__func__, &mas, 0, entry); + if (WARN_ON_ONCE(xa_is_advanced(entry))) + return -EINVAL; + + if (index > last) + return -EINVAL; + + mtree_lock(mt); +retry: + mas_wr_store_entry(&wr_mas); + if (mas_nomem(&mas, gfp)) + goto retry; + + mtree_unlock(mt); + if (mas_is_err(&mas)) + return xa_err(mas.node); + + return 0; +} +EXPORT_SYMBOL(mtree_store_range); + +/** + * mtree_store() - Store an entry at a given index. + * @mt: The maple tree + * @index: The index to store the value + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations + * + * Return: 0 on success, -EINVAL on invalid request, -ENOMEM if memory could not + * be allocated. + */ +int mtree_store(struct maple_tree *mt, unsigned long index, void *entry, + gfp_t gfp) +{ + return mtree_store_range(mt, index, index, entry, gfp); +} +EXPORT_SYMBOL(mtree_store); + +/** + * mtree_insert_range() - Insert an entry at a give range if there is no value. + * @mt: The maple tree + * @first: The start of the range + * @last: The end of the range + * @entry: The entry to store + * @gfp: The GFP_FLAGS to use for allocations. + * + * Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid + * request, -ENOMEM if memory could not be allocated. + */ +int mtree_insert_range(struct maple_tree *mt, unsigned long first, + unsigned long last, void *entry, gfp_t gfp) +{ + MA_STATE(ms, mt, first, last); + + if (WARN_ON_ONCE(xa_is_advanced(entry))) + return -EINVAL; + + if (first > last) + return -EINVAL; + + mtree_lock(mt); +retry: + mas_insert(&ms, entry); + if (mas_nomem(&ms, gfp)) + goto retry; + + mtree_unlock(mt); + if (mas_is_err(&ms)) + return xa_err(ms.node); + + return 0; +} +EXPORT_SYMBOL(mtree_insert_range); + +/** + * mtree_insert() - Insert an entry at a give index if there is no value. + * @mt: The maple tree + * @index : The index to store the value + * @entry: The entry to store + * @gfp: The FGP_FLAGS to use for allocations. + * + * Return: 0 on success, -EEXISTS if the range is occupied, -EINVAL on invalid + * request, -ENOMEM if memory could not be allocated. + */ +int mtree_insert(struct maple_tree *mt, unsigned long index, void *entry, + gfp_t gfp) +{ + return mtree_insert_range(mt, index, index, entry, gfp); +} +EXPORT_SYMBOL(mtree_insert); + +int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp, + void *entry, unsigned long size, unsigned long min, + unsigned long max, gfp_t gfp) +{ + int ret = 0; + + MA_STATE(mas, mt, min, max - size); + if (!mt_is_alloc(mt)) + return -EINVAL; + + if (WARN_ON_ONCE(mt_is_reserved(entry))) + return -EINVAL; + + if (min > max) + return -EINVAL; + + if (max < size) + return -EINVAL; + + if (!size) + return -EINVAL; + + mtree_lock(mt); +retry: + mas.offset = 0; + mas.index = min; + mas.last = max - size; + ret = mas_alloc(&mas, entry, size, startp); + if (mas_nomem(&mas, gfp)) + goto retry; + + mtree_unlock(mt); + return ret; +} +EXPORT_SYMBOL(mtree_alloc_range); + +int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp, + void *entry, unsigned long size, unsigned long min, + unsigned long max, gfp_t gfp) +{ + int ret = 0; + + MA_STATE(mas, mt, min, max - size); + if (!mt_is_alloc(mt)) + return -EINVAL; + + if (WARN_ON_ONCE(mt_is_reserved(entry))) + return -EINVAL; + + if (min >= max) + return -EINVAL; + + if (max < size - 1) + return -EINVAL; + + if (!size) + return -EINVAL; + + mtree_lock(mt); +retry: + ret = mas_rev_alloc(&mas, min, max, entry, size, startp); + if (mas_nomem(&mas, gfp)) + goto retry; + + mtree_unlock(mt); + return ret; +} +EXPORT_SYMBOL(mtree_alloc_rrange); + +/** + * mtree_erase() - Find an index and erase the entire range. + * @mt: The maple tree + * @index: The index to erase + * + * Erasing is the same as a walk to an entry then a store of a NULL to that + * ENTIRE range. In fact, it is implemented as such using the advanced API. + * + * Return: The entry stored at the @index or %NULL + */ +void *mtree_erase(struct maple_tree *mt, unsigned long index) +{ + void *entry = NULL; + + MA_STATE(mas, mt, index, index); + trace_ma_op(__func__, &mas); + + mtree_lock(mt); + entry = mas_erase(&mas); + mtree_unlock(mt); + + return entry; +} +EXPORT_SYMBOL(mtree_erase); + +/** + * __mt_destroy() - Walk and free all nodes of a locked maple tree. + * @mt: The maple tree + * + * Note: Does not handle locking. + */ +void __mt_destroy(struct maple_tree *mt) +{ + void *root = mt_root_locked(mt); + + rcu_assign_pointer(mt->ma_root, NULL); + if (xa_is_node(root)) + mte_destroy_walk(root, mt); + + mt->ma_flags = 0; +} +EXPORT_SYMBOL_GPL(__mt_destroy); + +/** + * mtree_destroy() - Destroy a maple tree + * @mt: The maple tree + * + * Frees all resources used by the tree. Handles locking. + */ +void mtree_destroy(struct maple_tree *mt) +{ + mtree_lock(mt); + __mt_destroy(mt); + mtree_unlock(mt); +} +EXPORT_SYMBOL(mtree_destroy); + +/** + * mt_find() - Search from the start up until an entry is found. + * @mt: The maple tree + * @index: Pointer which contains the start location of the search + * @max: The maximum value to check + * + * Handles locking. @index will be incremented to one beyond the range. + * + * Return: The entry at or after the @index or %NULL + */ +void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max) +{ + MA_STATE(mas, mt, *index, *index); + void *entry; +#ifdef CONFIG_DEBUG_MAPLE_TREE + unsigned long copy = *index; +#endif + + trace_ma_read(__func__, &mas); + + if ((*index) > max) + return NULL; + + rcu_read_lock(); +retry: + entry = mas_state_walk(&mas); + if (mas_is_start(&mas)) + goto retry; + + if (unlikely(xa_is_zero(entry))) + entry = NULL; + + if (entry) + goto unlock; + + while (mas_searchable(&mas) && (mas.index < max)) { + entry = mas_next_entry(&mas, max); + if (likely(entry && !xa_is_zero(entry))) + break; + } + + if (unlikely(xa_is_zero(entry))) + entry = NULL; +unlock: + rcu_read_unlock(); + if (likely(entry)) { + *index = mas.last + 1; +#ifdef CONFIG_DEBUG_MAPLE_TREE + if ((*index) && (*index) <= copy) + pr_err("index not increased! %lx <= %lx\n", + *index, copy); + MT_BUG_ON(mt, (*index) && ((*index) <= copy)); +#endif + } + + return entry; +} +EXPORT_SYMBOL(mt_find); + +/** + * mt_find_after() - Search from the start up until an entry is found. + * @mt: The maple tree + * @index: Pointer which contains the start location of the search + * @max: The maximum value to check + * + * Handles locking, detects wrapping on index == 0 + * + * Return: The entry at or after the @index or %NULL + */ +void *mt_find_after(struct maple_tree *mt, unsigned long *index, + unsigned long max) +{ + if (!(*index)) + return NULL; + + return mt_find(mt, index, max); +} +EXPORT_SYMBOL(mt_find_after); + +#ifdef CONFIG_DEBUG_MAPLE_TREE +atomic_t maple_tree_tests_run; +EXPORT_SYMBOL_GPL(maple_tree_tests_run); +atomic_t maple_tree_tests_passed; +EXPORT_SYMBOL_GPL(maple_tree_tests_passed); + +#ifndef __KERNEL__ +extern void kmem_cache_set_non_kernel(struct kmem_cache *, unsigned int); +void mt_set_non_kernel(unsigned int val) +{ + kmem_cache_set_non_kernel(maple_node_cache, val); +} + +extern unsigned long kmem_cache_get_alloc(struct kmem_cache *); +unsigned long mt_get_alloc_size(void) +{ + return kmem_cache_get_alloc(maple_node_cache); +} + +extern void kmem_cache_zero_nr_tallocated(struct kmem_cache *); +void mt_zero_nr_tallocated(void) +{ + kmem_cache_zero_nr_tallocated(maple_node_cache); +} + +extern unsigned int kmem_cache_nr_tallocated(struct kmem_cache *); +unsigned int mt_nr_tallocated(void) +{ + return kmem_cache_nr_tallocated(maple_node_cache); +} + +extern unsigned int kmem_cache_nr_allocated(struct kmem_cache *); +unsigned int mt_nr_allocated(void) +{ + return kmem_cache_nr_allocated(maple_node_cache); +} + +/* + * mas_dead_node() - Check if the maple state is pointing to a dead node. + * @mas: The maple state + * @index: The index to restore in @mas. + * + * Used in test code. + * Return: 1 if @mas has been reset to MAS_START, 0 otherwise. + */ +static inline int mas_dead_node(struct ma_state *mas, unsigned long index) +{ + if (unlikely(!mas_searchable(mas) || mas_is_start(mas))) + return 0; + + if (likely(!mte_dead_node(mas->node))) + return 0; + + mas_rewalk(mas, index); + return 1; +} +#endif /* not defined __KERNEL__ */ + +/* + * mas_get_slot() - Get the entry in the maple state node stored at @offset. + * @mas: The maple state + * @offset: The offset into the slot array to fetch. + * + * Return: The entry stored at @offset. + */ +static inline struct maple_enode *mas_get_slot(struct ma_state *mas, + unsigned char offset) +{ + return mas_slot(mas, ma_slots(mas_mn(mas), mte_node_type(mas->node)), + offset); +} + + +/* + * mas_first_entry() - Go the first leaf and find the first entry. + * @mas: the maple state. + * @limit: the maximum index to check. + * @*r_start: Pointer to set to the range start. + * + * Sets mas->offset to the offset of the entry, r_start to the range minimum. + * + * Return: The first entry or MAS_NONE. + */ +static inline void *mas_first_entry(struct ma_state *mas, struct maple_node *mn, + unsigned long limit, enum maple_type mt) + +{ + unsigned long max; + unsigned long *pivots; + void __rcu **slots; + void *entry = NULL; + + mas->index = mas->min; + if (mas->index > limit) + goto none; + + max = mas->max; + mas->offset = 0; + while (likely(!ma_is_leaf(mt))) { + MT_BUG_ON(mas->tree, mte_dead_node(mas->node)); + slots = ma_slots(mn, mt); + pivots = ma_pivots(mn, mt); + max = pivots[0]; + entry = mas_slot(mas, slots, 0); + if (unlikely(ma_dead_node(mn))) + return NULL; + mas->node = entry; + mn = mas_mn(mas); + mt = mte_node_type(mas->node); + } + MT_BUG_ON(mas->tree, mte_dead_node(mas->node)); + + mas->max = max; + slots = ma_slots(mn, mt); + entry = mas_slot(mas, slots, 0); + if (unlikely(ma_dead_node(mn))) + return NULL; + + /* Slot 0 or 1 must be set */ + if (mas->index > limit) + goto none; + + if (likely(entry)) + return entry; + + pivots = ma_pivots(mn, mt); + mas->index = pivots[0] + 1; + mas->offset = 1; + entry = mas_slot(mas, slots, 1); + if (unlikely(ma_dead_node(mn))) + return NULL; + + if (mas->index > limit) + goto none; + + if (likely(entry)) + return entry; + +none: + if (likely(!ma_dead_node(mn))) + mas->node = MAS_NONE; + return NULL; +} + +/* Depth first search, post-order */ +static void mas_dfs_postorder(struct ma_state *mas, unsigned long max) +{ + + struct maple_enode *p = MAS_NONE, *mn = mas->node; + unsigned long p_min, p_max; + + mas_next_node(mas, mas_mn(mas), max); + if (!mas_is_none(mas)) + return; + + if (mte_is_root(mn)) + return; + + mas->node = mn; + mas_ascend(mas); + while (mas->node != MAS_NONE) { + p = mas->node; + p_min = mas->min; + p_max = mas->max; + mas_prev_node(mas, 0); + } + + if (p == MAS_NONE) + return; + + mas->node = p; + mas->max = p_max; + mas->min = p_min; +} + +/* Tree validations */ +static void mt_dump_node(const struct maple_tree *mt, void *entry, + unsigned long min, unsigned long max, unsigned int depth); +static void mt_dump_range(unsigned long min, unsigned long max, + unsigned int depth) +{ + static const char spaces[] = " "; + + if (min == max) + pr_info("%.*s%lu: ", depth * 2, spaces, min); + else + pr_info("%.*s%lu-%lu: ", depth * 2, spaces, min, max); +} + +static void mt_dump_entry(void *entry, unsigned long min, unsigned long max, + unsigned int depth) +{ + mt_dump_range(min, max, depth); + + if (xa_is_value(entry)) + pr_cont("value %ld (0x%lx) [%p]\n", xa_to_value(entry), + xa_to_value(entry), entry); + else if (xa_is_zero(entry)) + pr_cont("zero (%ld)\n", xa_to_internal(entry)); + else if (mt_is_reserved(entry)) + pr_cont("UNKNOWN ENTRY (%p)\n", entry); + else + pr_cont("%p\n", entry); +} + +static void mt_dump_range64(const struct maple_tree *mt, void *entry, + unsigned long min, unsigned long max, unsigned int depth) +{ + struct maple_range_64 *node = &mte_to_node(entry)->mr64; + bool leaf = mte_is_leaf(entry); + unsigned long first = min; + int i; + + pr_cont(" contents: "); + for (i = 0; i < MAPLE_RANGE64_SLOTS - 1; i++) + pr_cont("%p %lu ", node->slot[i], node->pivot[i]); + pr_cont("%p\n", node->slot[i]); + for (i = 0; i < MAPLE_RANGE64_SLOTS; i++) { + unsigned long last = max; + + if (i < (MAPLE_RANGE64_SLOTS - 1)) + last = node->pivot[i]; + else if (!node->slot[i] && max != mt_max[mte_node_type(entry)]) + break; + if (last == 0 && i > 0) + break; + if (leaf) + mt_dump_entry(mt_slot(mt, node->slot, i), + first, last, depth + 1); + else if (node->slot[i]) + mt_dump_node(mt, mt_slot(mt, node->slot, i), + first, last, depth + 1); + + if (last == max) + break; + if (last > max) { + pr_err("node %p last (%lu) > max (%lu) at pivot %d!\n", + node, last, max, i); + break; + } + first = last + 1; + } +} + +static void mt_dump_arange64(const struct maple_tree *mt, void *entry, + unsigned long min, unsigned long max, unsigned int depth) +{ + struct maple_arange_64 *node = &mte_to_node(entry)->ma64; + bool leaf = mte_is_leaf(entry); + unsigned long first = min; + int i; + + pr_cont(" contents: "); + for (i = 0; i < MAPLE_ARANGE64_SLOTS; i++) + pr_cont("%lu ", node->gap[i]); + pr_cont("| %02X %02X| ", node->meta.end, node->meta.gap); + for (i = 0; i < MAPLE_ARANGE64_SLOTS - 1; i++) + pr_cont("%p %lu ", node->slot[i], node->pivot[i]); + pr_cont("%p\n", node->slot[i]); + for (i = 0; i < MAPLE_ARANGE64_SLOTS; i++) { + unsigned long last = max; + + if (i < (MAPLE_ARANGE64_SLOTS - 1)) + last = node->pivot[i]; + else if (!node->slot[i]) + break; + if (last == 0 && i > 0) + break; + if (leaf) + mt_dump_entry(mt_slot(mt, node->slot, i), + first, last, depth + 1); + else if (node->slot[i]) + mt_dump_node(mt, mt_slot(mt, node->slot, i), + first, last, depth + 1); + + if (last == max) + break; + if (last > max) { + pr_err("node %p last (%lu) > max (%lu) at pivot %d!\n", + node, last, max, i); + break; + } + first = last + 1; + } +} + +static void mt_dump_node(const struct maple_tree *mt, void *entry, + unsigned long min, unsigned long max, unsigned int depth) +{ + struct maple_node *node = mte_to_node(entry); + unsigned int type = mte_node_type(entry); + unsigned int i; + + mt_dump_range(min, max, depth); + + pr_cont("node %p depth %d type %d parent %p", node, depth, type, + node ? node->parent : NULL); + switch (type) { + case maple_dense: + pr_cont("\n"); + for (i = 0; i < MAPLE_NODE_SLOTS; i++) { + if (min + i > max) + pr_cont("OUT OF RANGE: "); + mt_dump_entry(mt_slot(mt, node->slot, i), + min + i, min + i, depth); + } + break; + case maple_leaf_64: + case maple_range_64: + mt_dump_range64(mt, entry, min, max, depth); + break; + case maple_arange_64: + mt_dump_arange64(mt, entry, min, max, depth); + break; + + default: + pr_cont(" UNKNOWN TYPE\n"); + } +} + +void mt_dump(const struct maple_tree *mt) +{ + void *entry = rcu_dereference_check(mt->ma_root, mt_locked(mt)); + + pr_info("maple_tree(%p) flags %X, height %u root %p\n", + mt, mt->ma_flags, mt_height(mt), entry); + if (!xa_is_node(entry)) + mt_dump_entry(entry, 0, 0, 0); + else if (entry) + mt_dump_node(mt, entry, 0, mt_max[mte_node_type(entry)], 0); +} + +/* + * Calculate the maximum gap in a node and check if that's what is reported in + * the parent (unless root). + */ +static void mas_validate_gaps(struct ma_state *mas) +{ + struct maple_enode *mte = mas->node; + struct maple_node *p_mn; + unsigned long gap = 0, max_gap = 0; + unsigned long p_end, p_start = mas->min; + unsigned char p_slot; + unsigned long *gaps = NULL; + unsigned long *pivots = ma_pivots(mte_to_node(mte), mte_node_type(mte)); + int i; + + if (ma_is_dense(mte_node_type(mte))) { + for (i = 0; i < mt_slot_count(mte); i++) { + if (mas_get_slot(mas, i)) { + if (gap > max_gap) + max_gap = gap; + gap = 0; + continue; + } + gap++; + } + goto counted; + } + + gaps = ma_gaps(mte_to_node(mte), mte_node_type(mte)); + for (i = 0; i < mt_slot_count(mte); i++) { + p_end = mas_logical_pivot(mas, pivots, i, mte_node_type(mte)); + + if (!gaps) { + if (mas_get_slot(mas, i)) { + gap = 0; + goto not_empty; + } + + gap += p_end - p_start + 1; + } else { + void *entry = mas_get_slot(mas, i); + + gap = gaps[i]; + if (!entry) { + if (gap != p_end - p_start + 1) { + pr_err("%p[%u] -> %p %lu != %lu - %lu + 1\n", + mas_mn(mas), i, + mas_get_slot(mas, i), gap, + p_end, p_start); + mt_dump(mas->tree); + + MT_BUG_ON(mas->tree, + gap != p_end - p_start + 1); + } + } else { + if (gap > p_end - p_start + 1) { + pr_err("%p[%u] %lu >= %lu - %lu + 1 (%lu)\n", + mas_mn(mas), i, gap, p_end, p_start, + p_end - p_start + 1); + MT_BUG_ON(mas->tree, + gap > p_end - p_start + 1); + } + } + } + + if (gap > max_gap) + max_gap = gap; +not_empty: + p_start = p_end + 1; + if (p_end >= mas->max) + break; + } + +counted: + if (mte_is_root(mte)) + return; + + p_slot = mte_parent_slot(mas->node); + p_mn = mte_parent(mte); + MT_BUG_ON(mas->tree, max_gap > mas->max); + if (ma_gaps(p_mn, mas_parent_enum(mas, mte))[p_slot] != max_gap) { + pr_err("gap %p[%u] != %lu\n", p_mn, p_slot, max_gap); + mt_dump(mas->tree); + } + + MT_BUG_ON(mas->tree, + ma_gaps(p_mn, mas_parent_enum(mas, mte))[p_slot] != max_gap); +} + +static void mas_validate_parent_slot(struct ma_state *mas) +{ + struct maple_node *parent; + struct maple_enode *node; + enum maple_type p_type = mas_parent_enum(mas, mas->node); + unsigned char p_slot = mte_parent_slot(mas->node); + void __rcu **slots; + int i; + + if (mte_is_root(mas->node)) + return; + + parent = mte_parent(mas->node); + slots = ma_slots(parent, p_type); + MT_BUG_ON(mas->tree, mas_mn(mas) == parent); + + /* Check prev/next parent slot for duplicate node entry */ + + for (i = 0; i < mt_slots[p_type]; i++) { + node = mas_slot(mas, slots, i); + if (i == p_slot) { + if (node != mas->node) + pr_err("parent %p[%u] does not have %p\n", + parent, i, mas_mn(mas)); + MT_BUG_ON(mas->tree, node != mas->node); + } else if (node == mas->node) { + pr_err("Invalid child %p at parent %p[%u] p_slot %u\n", + mas_mn(mas), parent, i, p_slot); + MT_BUG_ON(mas->tree, node == mas->node); + } + } +} + +static void mas_validate_child_slot(struct ma_state *mas) +{ + enum maple_type type = mte_node_type(mas->node); + void __rcu **slots = ma_slots(mte_to_node(mas->node), type); + unsigned long *pivots = ma_pivots(mte_to_node(mas->node), type); + struct maple_enode *child; + unsigned char i; + + if (mte_is_leaf(mas->node)) + return; + + for (i = 0; i < mt_slots[type]; i++) { + child = mas_slot(mas, slots, i); + if (!pivots[i] || pivots[i] == mas->max) + break; + + if (!child) + break; + + if (mte_parent_slot(child) != i) { + pr_err("Slot error at %p[%u]: child %p has pslot %u\n", + mas_mn(mas), i, mte_to_node(child), + mte_parent_slot(child)); + MT_BUG_ON(mas->tree, 1); + } + + if (mte_parent(child) != mte_to_node(mas->node)) { + pr_err("child %p has parent %p not %p\n", + mte_to_node(child), mte_parent(child), + mte_to_node(mas->node)); + MT_BUG_ON(mas->tree, 1); + } + } +} + +/* + * Validate all pivots are within mas->min and mas->max. + */ +static void mas_validate_limits(struct ma_state *mas) +{ + int i; + unsigned long prev_piv = 0; + enum maple_type type = mte_node_type(mas->node); + void __rcu **slots = ma_slots(mte_to_node(mas->node), type); + unsigned long *pivots = ma_pivots(mas_mn(mas), type); + + /* all limits are fine here. */ + if (mte_is_root(mas->node)) + return; + + for (i = 0; i < mt_slots[type]; i++) { + unsigned long piv; + + piv = mas_safe_pivot(mas, pivots, i, type); + + if (!piv && (i != 0)) + break; + + if (!mte_is_leaf(mas->node)) { + void *entry = mas_slot(mas, slots, i); + + if (!entry) + pr_err("%p[%u] cannot be null\n", + mas_mn(mas), i); + + MT_BUG_ON(mas->tree, !entry); + } + + if (prev_piv > piv) { + pr_err("%p[%u] piv %lu < prev_piv %lu\n", + mas_mn(mas), i, piv, prev_piv); + MT_BUG_ON(mas->tree, piv < prev_piv); + } + + if (piv < mas->min) { + pr_err("%p[%u] %lu < %lu\n", mas_mn(mas), i, + piv, mas->min); + MT_BUG_ON(mas->tree, piv < mas->min); + } + if (piv > mas->max) { + pr_err("%p[%u] %lu > %lu\n", mas_mn(mas), i, + piv, mas->max); + MT_BUG_ON(mas->tree, piv > mas->max); + } + prev_piv = piv; + if (piv == mas->max) + break; + } + for (i += 1; i < mt_slots[type]; i++) { + void *entry = mas_slot(mas, slots, i); + + if (entry && (i != mt_slots[type] - 1)) { + pr_err("%p[%u] should not have entry %p\n", mas_mn(mas), + i, entry); + MT_BUG_ON(mas->tree, entry != NULL); + } + + if (i < mt_pivots[type]) { + unsigned long piv = pivots[i]; + + if (!piv) + continue; + + pr_err("%p[%u] should not have piv %lu\n", + mas_mn(mas), i, piv); + MT_BUG_ON(mas->tree, i < mt_pivots[type] - 1); + } + } +} + +static void mt_validate_nulls(struct maple_tree *mt) +{ + void *entry, *last = (void *)1; + unsigned char offset = 0; + void __rcu **slots; + MA_STATE(mas, mt, 0, 0); + + mas_start(&mas); + if (mas_is_none(&mas) || (mas.node == MAS_ROOT)) + return; + + while (!mte_is_leaf(mas.node)) + mas_descend(&mas); + + slots = ma_slots(mte_to_node(mas.node), mte_node_type(mas.node)); + do { + entry = mas_slot(&mas, slots, offset); + if (!last && !entry) { + pr_err("Sequential nulls end at %p[%u]\n", + mas_mn(&mas), offset); + } + MT_BUG_ON(mt, !last && !entry); + last = entry; + if (offset == mas_data_end(&mas)) { + mas_next_node(&mas, mas_mn(&mas), ULONG_MAX); + if (mas_is_none(&mas)) + return; + offset = 0; + slots = ma_slots(mte_to_node(mas.node), + mte_node_type(mas.node)); + } else { + offset++; + } + + } while (!mas_is_none(&mas)); +} + +/* + * validate a maple tree by checking: + * 1. The limits (pivots are within mas->min to mas->max) + * 2. The gap is correctly set in the parents + */ +void mt_validate(struct maple_tree *mt) +{ + unsigned char end; + + MA_STATE(mas, mt, 0, 0); + rcu_read_lock(); + mas_start(&mas); + if (!mas_searchable(&mas)) + goto done; + + mas_first_entry(&mas, mas_mn(&mas), ULONG_MAX, mte_node_type(mas.node)); + while (!mas_is_none(&mas)) { + MT_BUG_ON(mas.tree, mte_dead_node(mas.node)); + if (!mte_is_root(mas.node)) { + end = mas_data_end(&mas); + if ((end < mt_min_slot_count(mas.node)) && + (mas.max != ULONG_MAX)) { + pr_err("Invalid size %u of %p\n", end, + mas_mn(&mas)); + MT_BUG_ON(mas.tree, 1); + } + + } + mas_validate_parent_slot(&mas); + mas_validate_child_slot(&mas); + mas_validate_limits(&mas); + if (mt_is_alloc(mt)) + mas_validate_gaps(&mas); + mas_dfs_postorder(&mas, ULONG_MAX); + } + mt_validate_nulls(mt); +done: + rcu_read_unlock(); + +} + +#endif /* CONFIG_DEBUG_MAPLE_TREE */ diff --git a/tools/testing/radix-tree/.gitignore b/tools/testing/radix-tree/.gitignore index d971516401e6..c901d96dd013 100644 --- a/tools/testing/radix-tree/.gitignore +++ b/tools/testing/radix-tree/.gitignore @@ -6,3 +6,5 @@ main multiorder radix-tree.c xarray +maple +ma_xa_benchmark diff --git a/tools/testing/radix-tree/generated/autoconf.h b/tools/testing/radix-tree/generated/autoconf.h index 2218b3cc184e..e7da80350236 100644 --- a/tools/testing/radix-tree/generated/autoconf.h +++ b/tools/testing/radix-tree/generated/autoconf.h @@ -1 +1,2 @@ #define CONFIG_XARRAY_MULTI 1 +#define CONFIG_64BIT 1 diff --git a/tools/testing/radix-tree/linux/maple_tree.h b/tools/testing/radix-tree/linux/maple_tree.h new file mode 100644 index 000000000000..7d8d1f445b89 --- /dev/null +++ b/tools/testing/radix-tree/linux/maple_tree.h @@ -0,0 +1,7 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +#define atomic_t int32_t +#include "../../../../include/linux/maple_tree.h" +#define atomic_inc(x) uatomic_inc(x) +#define atomic_read(x) uatomic_read(x) +#define atomic_set(x, y) do {} while (0) +#define U8_MAX UCHAR_MAX diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c new file mode 100644 index 000000000000..35082671928a --- /dev/null +++ b/tools/testing/radix-tree/maple.c @@ -0,0 +1,59 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * maple_tree.c: Userspace shim for maple tree test-suite + * Copyright (c) 2018 Liam R. Howlett + */ + +#define CONFIG_DEBUG_MAPLE_TREE +#define CONFIG_MAPLE_SEARCH +#include "test.h" + +#define module_init(x) +#define module_exit(x) +#define MODULE_AUTHOR(x) +#define MODULE_LICENSE(x) +#define dump_stack() assert(0) + +#include "../../../lib/maple_tree.c" +#undef CONFIG_DEBUG_MAPLE_TREE +#include "../../../lib/test_maple_tree.c" + +void farmer_tests(void) +{ + struct maple_node *node; + DEFINE_MTREE(tree); + + mt_dump(&tree); + + tree.ma_root = xa_mk_value(0); + mt_dump(&tree); + + node = mt_alloc_one(GFP_KERNEL); + node->parent = (void *)((unsigned long)(&tree) | 1); + node->slot[0] = xa_mk_value(0); + node->slot[1] = xa_mk_value(1); + node->mr64.pivot[0] = 0; + node->mr64.pivot[1] = 1; + node->mr64.pivot[2] = 0; + tree.ma_root = mt_mk_node(node, maple_leaf_64); + mt_dump(&tree); + + ma_free_rcu(node); +} + +void maple_tree_tests(void) +{ + farmer_tests(); + maple_tree_seed(); + maple_tree_harvest(); +} + +int __weak main(void) +{ + maple_tree_init(); + maple_tree_tests(); + rcu_barrier(); + if (nr_allocated) + printf("nr_allocated = %d\n", nr_allocated); + return 0; +} diff --git a/tools/testing/radix-tree/trace/events/maple_tree.h b/tools/testing/radix-tree/trace/events/maple_tree.h new file mode 100644 index 000000000000..97d0e1ddcf08 --- /dev/null +++ b/tools/testing/radix-tree/trace/events/maple_tree.h @@ -0,0 +1,5 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +#define trace_ma_op(a, b) do {} while (0) +#define trace_ma_read(a, b) do {} while (0) +#define trace_ma_write(a, b, c, d) do {} while (0) -- cgit v1.2.3 From 21b7bdb504ae6b0a795c8d63818611ce02b532c1 Mon Sep 17 00:00:00 2001 From: xu xin Date: Tue, 30 Aug 2022 14:40:03 +0000 Subject: ksm: add profit monitoring documentation Add the description of KSM profit and how to determine it separately in system-wide range and inner a single process. Link: https://lkml.kernel.org/r/20220830144003.299870-1-xu.xin16@zte.com.cn Signed-off-by: xu xin Reviewed-by: Xiaokai Ran Reviewed-by: Yang Yang Reviewed-by: Bagas Sanjaya Cc: Alexey Dobriyan Cc: Hugh Dickins Cc: Izik Eidus Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/ksm.rst | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/ksm.rst b/Documentation/admin-guide/mm/ksm.rst index b244f0202a03..fb6ba2002a4b 100644 --- a/Documentation/admin-guide/mm/ksm.rst +++ b/Documentation/admin-guide/mm/ksm.rst @@ -184,6 +184,42 @@ The maximum possible ``pages_sharing/pages_shared`` ratio is limited by the ``max_page_sharing`` tunable. To increase the ratio ``max_page_sharing`` must be increased accordingly. +Monitoring KSM profit +===================== + +KSM can save memory by merging identical pages, but also can consume +additional memory, because it needs to generate a number of rmap_items to +save each scanned page's brief rmap information. Some of these pages may +be merged, but some may not be abled to be merged after being checked +several times, which are unprofitable memory consumed. + +1) How to determine whether KSM save memory or consume memory in system-wide + range? Here is a simple approximate calculation for reference:: + + general_profit =~ pages_sharing * sizeof(page) - (all_rmap_items) * + sizeof(rmap_item); + + where all_rmap_items can be easily obtained by summing ``pages_sharing``, + ``pages_shared``, ``pages_unshared`` and ``pages_volatile``. + +2) The KSM profit inner a single process can be similarly obtained by the + following approximate calculation:: + + process_profit =~ ksm_merging_pages * sizeof(page) - + ksm_rmap_items * sizeof(rmap_item). + + where ksm_merging_pages is shown under the directory ``/proc//``, + and ksm_rmap_items is shown in ``/proc//ksm_stat``. + +From the perspective of application, a high ratio of ``ksm_rmap_items`` to +``ksm_merging_pages`` means a bad madvise-applied policy, so developers or +administrators have to rethink how to change madvise policy. Giving an example +for reference, a page's size is usually 4K, and the rmap_item's size is +separately 32B on 32-bit CPU architecture and 64B on 64-bit CPU architecture. +so if the ``ksm_rmap_items/ksm_merging_pages`` ratio exceeds 64 on 64-bit CPU +or exceeds 128 on 32-bit CPU, then the app's madvise policy should be dropped, +because the ksm profit is approximately zero or negative. + Monitoring KSM events ===================== -- cgit v1.2.3 From 21fbd59136e0773e0b920371860d9b6757cdb250 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Wed, 31 Aug 2022 11:19:48 +0800 Subject: ksm: add the ksm prefix to the names of the ksm private structures In order to prevent the name of the private structure of ksm from being the same as the name of the common structure used in subsequent patches, prefix their names with ksm in advance. Link: https://lkml.kernel.org/r/20220831031951.43152-5-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Cc: Johannes Weiner Cc: Matthew Wilcox Cc: Mike Rapoport Cc: Minchan Kim Cc: Vlastimil Babka Cc: Yang Shi Signed-off-by: Andrew Morton --- Documentation/mm/ksm.rst | 2 +- mm/ksm.c | 216 +++++++++++++++++++++++------------------------ 2 files changed, 109 insertions(+), 109 deletions(-) (limited to 'Documentation') diff --git a/Documentation/mm/ksm.rst b/Documentation/mm/ksm.rst index 9e37add068e6..f83cfbc12f4c 100644 --- a/Documentation/mm/ksm.rst +++ b/Documentation/mm/ksm.rst @@ -26,7 +26,7 @@ tree. If a KSM page is shared between less than ``max_page_sharing`` VMAs, the node of the stable tree that represents such KSM page points to a -list of struct rmap_item and the ``page->mapping`` of the +list of struct ksm_rmap_item and the ``page->mapping`` of the KSM page points to the stable tree node. When the sharing passes this threshold, KSM adds a second dimension to diff --git a/mm/ksm.c b/mm/ksm.c index 0cd2f4b62334..de61946106ce 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -82,7 +82,7 @@ * different KSM page copy of that content * * Internally, the regular nodes, "dups" and "chains" are represented - * using the same struct stable_node structure. + * using the same struct ksm_stable_node structure. * * In addition to the stable tree, KSM uses a second data structure called the * unstable tree: this tree holds pointers to pages which have been found to @@ -112,16 +112,16 @@ */ /** - * struct mm_slot - ksm information per mm that is being scanned + * struct ksm_mm_slot - ksm information per mm that is being scanned * @link: link to the mm_slots hash list * @mm_list: link into the mm_slots list, rooted in ksm_mm_head * @rmap_list: head for this mm_slot's singly-linked list of rmap_items * @mm: the mm that this information is valid for */ -struct mm_slot { +struct ksm_mm_slot { struct hlist_node link; struct list_head mm_list; - struct rmap_item *rmap_list; + struct ksm_rmap_item *rmap_list; struct mm_struct *mm; }; @@ -135,14 +135,14 @@ struct mm_slot { * There is only the one ksm_scan instance of this cursor structure. */ struct ksm_scan { - struct mm_slot *mm_slot; + struct ksm_mm_slot *mm_slot; unsigned long address; - struct rmap_item **rmap_list; + struct ksm_rmap_item **rmap_list; unsigned long seqnr; }; /** - * struct stable_node - node of the stable rbtree + * struct ksm_stable_node - node of the stable rbtree * @node: rb node of this ksm page in the stable tree * @head: (overlaying parent) &migrate_nodes indicates temporarily on that list * @hlist_dup: linked into the stable_node->hlist with a stable_node chain @@ -153,7 +153,7 @@ struct ksm_scan { * @rmap_hlist_len: number of rmap_item entries in hlist or STABLE_NODE_CHAIN * @nid: NUMA node id of stable tree in which linked (may not match kpfn) */ -struct stable_node { +struct ksm_stable_node { union { struct rb_node node; /* when node of stable tree */ struct { /* when listed for migration */ @@ -182,7 +182,7 @@ struct stable_node { }; /** - * struct rmap_item - reverse mapping item for virtual addresses + * struct ksm_rmap_item - reverse mapping item for virtual addresses * @rmap_list: next rmap_item in mm_slot's singly-linked rmap_list * @anon_vma: pointer to anon_vma for this mm,address, when in stable tree * @nid: NUMA node id of unstable tree in which linked (may not match page) @@ -193,8 +193,8 @@ struct stable_node { * @head: pointer to stable_node heading this list in the stable tree * @hlist: link into hlist of rmap_items hanging off that stable_node */ -struct rmap_item { - struct rmap_item *rmap_list; +struct ksm_rmap_item { + struct ksm_rmap_item *rmap_list; union { struct anon_vma *anon_vma; /* when stable */ #ifdef CONFIG_NUMA @@ -207,7 +207,7 @@ struct rmap_item { union { struct rb_node node; /* when node of unstable tree */ struct { /* when listed from stable tree */ - struct stable_node *head; + struct ksm_stable_node *head; struct hlist_node hlist; }; }; @@ -230,7 +230,7 @@ static LIST_HEAD(migrate_nodes); #define MM_SLOTS_HASH_BITS 10 static DEFINE_HASHTABLE(mm_slots_hash, MM_SLOTS_HASH_BITS); -static struct mm_slot ksm_mm_head = { +static struct ksm_mm_slot ksm_mm_head = { .mm_list = LIST_HEAD_INIT(ksm_mm_head.mm_list), }; static struct ksm_scan ksm_scan = { @@ -298,21 +298,21 @@ static DECLARE_WAIT_QUEUE_HEAD(ksm_iter_wait); static DEFINE_MUTEX(ksm_thread_mutex); static DEFINE_SPINLOCK(ksm_mmlist_lock); -#define KSM_KMEM_CACHE(__struct, __flags) kmem_cache_create("ksm_"#__struct,\ +#define KSM_KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\ sizeof(struct __struct), __alignof__(struct __struct),\ (__flags), NULL) static int __init ksm_slab_init(void) { - rmap_item_cache = KSM_KMEM_CACHE(rmap_item, 0); + rmap_item_cache = KSM_KMEM_CACHE(ksm_rmap_item, 0); if (!rmap_item_cache) goto out; - stable_node_cache = KSM_KMEM_CACHE(stable_node, 0); + stable_node_cache = KSM_KMEM_CACHE(ksm_stable_node, 0); if (!stable_node_cache) goto out_free1; - mm_slot_cache = KSM_KMEM_CACHE(mm_slot, 0); + mm_slot_cache = KSM_KMEM_CACHE(ksm_mm_slot, 0); if (!mm_slot_cache) goto out_free2; @@ -334,18 +334,18 @@ static void __init ksm_slab_free(void) mm_slot_cache = NULL; } -static __always_inline bool is_stable_node_chain(struct stable_node *chain) +static __always_inline bool is_stable_node_chain(struct ksm_stable_node *chain) { return chain->rmap_hlist_len == STABLE_NODE_CHAIN; } -static __always_inline bool is_stable_node_dup(struct stable_node *dup) +static __always_inline bool is_stable_node_dup(struct ksm_stable_node *dup) { return dup->head == STABLE_NODE_DUP_HEAD; } -static inline void stable_node_chain_add_dup(struct stable_node *dup, - struct stable_node *chain) +static inline void stable_node_chain_add_dup(struct ksm_stable_node *dup, + struct ksm_stable_node *chain) { VM_BUG_ON(is_stable_node_dup(dup)); dup->head = STABLE_NODE_DUP_HEAD; @@ -354,14 +354,14 @@ static inline void stable_node_chain_add_dup(struct stable_node *dup, ksm_stable_node_dups++; } -static inline void __stable_node_dup_del(struct stable_node *dup) +static inline void __stable_node_dup_del(struct ksm_stable_node *dup) { VM_BUG_ON(!is_stable_node_dup(dup)); hlist_del(&dup->hlist_dup); ksm_stable_node_dups--; } -static inline void stable_node_dup_del(struct stable_node *dup) +static inline void stable_node_dup_del(struct ksm_stable_node *dup) { VM_BUG_ON(is_stable_node_chain(dup)); if (is_stable_node_dup(dup)) @@ -373,9 +373,9 @@ static inline void stable_node_dup_del(struct stable_node *dup) #endif } -static inline struct rmap_item *alloc_rmap_item(void) +static inline struct ksm_rmap_item *alloc_rmap_item(void) { - struct rmap_item *rmap_item; + struct ksm_rmap_item *rmap_item; rmap_item = kmem_cache_zalloc(rmap_item_cache, GFP_KERNEL | __GFP_NORETRY | __GFP_NOWARN); @@ -384,7 +384,7 @@ static inline struct rmap_item *alloc_rmap_item(void) return rmap_item; } -static inline void free_rmap_item(struct rmap_item *rmap_item) +static inline void free_rmap_item(struct ksm_rmap_item *rmap_item) { ksm_rmap_items--; rmap_item->mm->ksm_rmap_items--; @@ -392,7 +392,7 @@ static inline void free_rmap_item(struct rmap_item *rmap_item) kmem_cache_free(rmap_item_cache, rmap_item); } -static inline struct stable_node *alloc_stable_node(void) +static inline struct ksm_stable_node *alloc_stable_node(void) { /* * The allocation can take too long with GFP_KERNEL when memory is under @@ -402,28 +402,28 @@ static inline struct stable_node *alloc_stable_node(void) return kmem_cache_alloc(stable_node_cache, GFP_KERNEL | __GFP_HIGH); } -static inline void free_stable_node(struct stable_node *stable_node) +static inline void free_stable_node(struct ksm_stable_node *stable_node) { VM_BUG_ON(stable_node->rmap_hlist_len && !is_stable_node_chain(stable_node)); kmem_cache_free(stable_node_cache, stable_node); } -static inline struct mm_slot *alloc_mm_slot(void) +static inline struct ksm_mm_slot *alloc_mm_slot(void) { if (!mm_slot_cache) /* initialization failed */ return NULL; return kmem_cache_zalloc(mm_slot_cache, GFP_KERNEL); } -static inline void free_mm_slot(struct mm_slot *mm_slot) +static inline void free_mm_slot(struct ksm_mm_slot *mm_slot) { kmem_cache_free(mm_slot_cache, mm_slot); } -static struct mm_slot *get_mm_slot(struct mm_struct *mm) +static struct ksm_mm_slot *get_mm_slot(struct mm_struct *mm) { - struct mm_slot *slot; + struct ksm_mm_slot *slot; hash_for_each_possible(mm_slots_hash, slot, link, (unsigned long)mm) if (slot->mm == mm) @@ -433,7 +433,7 @@ static struct mm_slot *get_mm_slot(struct mm_struct *mm) } static void insert_to_mm_slots_hash(struct mm_struct *mm, - struct mm_slot *mm_slot) + struct ksm_mm_slot *mm_slot) { mm_slot->mm = mm; hash_add(mm_slots_hash, &mm_slot->link, (unsigned long)mm); @@ -529,7 +529,7 @@ static struct vm_area_struct *find_mergeable_vma(struct mm_struct *mm, return vma; } -static void break_cow(struct rmap_item *rmap_item) +static void break_cow(struct ksm_rmap_item *rmap_item) { struct mm_struct *mm = rmap_item->mm; unsigned long addr = rmap_item->address; @@ -548,7 +548,7 @@ static void break_cow(struct rmap_item *rmap_item) mmap_read_unlock(mm); } -static struct page *get_mergeable_page(struct rmap_item *rmap_item) +static struct page *get_mergeable_page(struct ksm_rmap_item *rmap_item) { struct mm_struct *mm = rmap_item->mm; unsigned long addr = rmap_item->address; @@ -589,10 +589,10 @@ static inline int get_kpfn_nid(unsigned long kpfn) return ksm_merge_across_nodes ? 0 : NUMA(pfn_to_nid(kpfn)); } -static struct stable_node *alloc_stable_node_chain(struct stable_node *dup, +static struct ksm_stable_node *alloc_stable_node_chain(struct ksm_stable_node *dup, struct rb_root *root) { - struct stable_node *chain = alloc_stable_node(); + struct ksm_stable_node *chain = alloc_stable_node(); VM_BUG_ON(is_stable_node_chain(dup)); if (likely(chain)) { INIT_HLIST_HEAD(&chain->hlist); @@ -622,7 +622,7 @@ static struct stable_node *alloc_stable_node_chain(struct stable_node *dup, return chain; } -static inline void free_stable_node_chain(struct stable_node *chain, +static inline void free_stable_node_chain(struct ksm_stable_node *chain, struct rb_root *root) { rb_erase(&chain->node, root); @@ -630,9 +630,9 @@ static inline void free_stable_node_chain(struct stable_node *chain, ksm_stable_node_chains--; } -static void remove_node_from_stable_tree(struct stable_node *stable_node) +static void remove_node_from_stable_tree(struct ksm_stable_node *stable_node) { - struct rmap_item *rmap_item; + struct ksm_rmap_item *rmap_item; /* check it's not STABLE_NODE_CHAIN or negative */ BUG_ON(stable_node->rmap_hlist_len < 0); @@ -694,7 +694,7 @@ enum get_ksm_page_flags { * a page to put something that might look like our key in page->mapping. * is on its way to being freed; but it is an anomaly to bear in mind. */ -static struct page *get_ksm_page(struct stable_node *stable_node, +static struct page *get_ksm_page(struct ksm_stable_node *stable_node, enum get_ksm_page_flags flags) { struct page *page; @@ -773,10 +773,10 @@ stale: * Removing rmap_item from stable or unstable tree. * This function will clean the information from the stable/unstable tree. */ -static void remove_rmap_item_from_tree(struct rmap_item *rmap_item) +static void remove_rmap_item_from_tree(struct ksm_rmap_item *rmap_item) { if (rmap_item->address & STABLE_FLAG) { - struct stable_node *stable_node; + struct ksm_stable_node *stable_node; struct page *page; stable_node = rmap_item->head; @@ -823,10 +823,10 @@ out: cond_resched(); /* we're called from many long loops */ } -static void remove_trailing_rmap_items(struct rmap_item **rmap_list) +static void remove_trailing_rmap_items(struct ksm_rmap_item **rmap_list) { while (*rmap_list) { - struct rmap_item *rmap_item = *rmap_list; + struct ksm_rmap_item *rmap_item = *rmap_list; *rmap_list = rmap_item->rmap_list; remove_rmap_item_from_tree(rmap_item); free_rmap_item(rmap_item); @@ -863,18 +863,18 @@ static int unmerge_ksm_pages(struct vm_area_struct *vma, return err; } -static inline struct stable_node *folio_stable_node(struct folio *folio) +static inline struct ksm_stable_node *folio_stable_node(struct folio *folio) { return folio_test_ksm(folio) ? folio_raw_mapping(folio) : NULL; } -static inline struct stable_node *page_stable_node(struct page *page) +static inline struct ksm_stable_node *page_stable_node(struct page *page) { return folio_stable_node(page_folio(page)); } static inline void set_page_stable_node(struct page *page, - struct stable_node *stable_node) + struct ksm_stable_node *stable_node) { VM_BUG_ON_PAGE(PageAnon(page) && PageAnonExclusive(page), page); page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); @@ -884,7 +884,7 @@ static inline void set_page_stable_node(struct page *page, /* * Only called through the sysfs control interface: */ -static int remove_stable_node(struct stable_node *stable_node) +static int remove_stable_node(struct ksm_stable_node *stable_node) { struct page *page; int err; @@ -922,10 +922,10 @@ static int remove_stable_node(struct stable_node *stable_node) return err; } -static int remove_stable_node_chain(struct stable_node *stable_node, +static int remove_stable_node_chain(struct ksm_stable_node *stable_node, struct rb_root *root) { - struct stable_node *dup; + struct ksm_stable_node *dup; struct hlist_node *hlist_safe; if (!is_stable_node_chain(stable_node)) { @@ -949,14 +949,14 @@ static int remove_stable_node_chain(struct stable_node *stable_node, static int remove_all_stable_nodes(void) { - struct stable_node *stable_node, *next; + struct ksm_stable_node *stable_node, *next; int nid; int err = 0; for (nid = 0; nid < ksm_nr_node_ids; nid++) { while (root_stable_tree[nid].rb_node) { stable_node = rb_entry(root_stable_tree[nid].rb_node, - struct stable_node, node); + struct ksm_stable_node, node); if (remove_stable_node_chain(stable_node, root_stable_tree + nid)) { err = -EBUSY; @@ -975,14 +975,14 @@ static int remove_all_stable_nodes(void) static int unmerge_and_remove_all_rmap_items(void) { - struct mm_slot *mm_slot; + struct ksm_mm_slot *mm_slot; struct mm_struct *mm; struct vm_area_struct *vma; int err = 0; spin_lock(&ksm_mmlist_lock); ksm_scan.mm_slot = list_entry(ksm_mm_head.mm_list.next, - struct mm_slot, mm_list); + struct ksm_mm_slot, mm_list); spin_unlock(&ksm_mmlist_lock); for (mm_slot = ksm_scan.mm_slot; mm_slot != &ksm_mm_head; @@ -1007,7 +1007,7 @@ static int unmerge_and_remove_all_rmap_items(void) spin_lock(&ksm_mmlist_lock); ksm_scan.mm_slot = list_entry(mm_slot->mm_list.next, - struct mm_slot, mm_list); + struct ksm_mm_slot, mm_list); if (ksm_test_exit(mm)) { hash_del(&mm_slot->link); list_del(&mm_slot->mm_list); @@ -1295,7 +1295,7 @@ out: * * This function returns 0 if the pages were merged, -EFAULT otherwise. */ -static int try_to_merge_with_ksm_page(struct rmap_item *rmap_item, +static int try_to_merge_with_ksm_page(struct ksm_rmap_item *rmap_item, struct page *page, struct page *kpage) { struct mm_struct *mm = rmap_item->mm; @@ -1332,9 +1332,9 @@ out: * Note that this function upgrades page to ksm page: if one of the pages * is already a ksm page, try_to_merge_with_ksm_page should be used. */ -static struct page *try_to_merge_two_pages(struct rmap_item *rmap_item, +static struct page *try_to_merge_two_pages(struct ksm_rmap_item *rmap_item, struct page *page, - struct rmap_item *tree_rmap_item, + struct ksm_rmap_item *tree_rmap_item, struct page *tree_page) { int err; @@ -1354,7 +1354,7 @@ static struct page *try_to_merge_two_pages(struct rmap_item *rmap_item, } static __always_inline -bool __is_page_sharing_candidate(struct stable_node *stable_node, int offset) +bool __is_page_sharing_candidate(struct ksm_stable_node *stable_node, int offset) { VM_BUG_ON(stable_node->rmap_hlist_len < 0); /* @@ -1368,17 +1368,17 @@ bool __is_page_sharing_candidate(struct stable_node *stable_node, int offset) } static __always_inline -bool is_page_sharing_candidate(struct stable_node *stable_node) +bool is_page_sharing_candidate(struct ksm_stable_node *stable_node) { return __is_page_sharing_candidate(stable_node, 0); } -static struct page *stable_node_dup(struct stable_node **_stable_node_dup, - struct stable_node **_stable_node, +static struct page *stable_node_dup(struct ksm_stable_node **_stable_node_dup, + struct ksm_stable_node **_stable_node, struct rb_root *root, bool prune_stale_stable_nodes) { - struct stable_node *dup, *found = NULL, *stable_node = *_stable_node; + struct ksm_stable_node *dup, *found = NULL, *stable_node = *_stable_node; struct hlist_node *hlist_safe; struct page *_tree_page, *tree_page = NULL; int nr = 0; @@ -1492,7 +1492,7 @@ static struct page *stable_node_dup(struct stable_node **_stable_node_dup, return tree_page; } -static struct stable_node *stable_node_dup_any(struct stable_node *stable_node, +static struct ksm_stable_node *stable_node_dup_any(struct ksm_stable_node *stable_node, struct rb_root *root) { if (!is_stable_node_chain(stable_node)) @@ -1519,12 +1519,12 @@ static struct stable_node *stable_node_dup_any(struct stable_node *stable_node, * function and will be overwritten in all cases, the caller doesn't * need to initialize it. */ -static struct page *__stable_node_chain(struct stable_node **_stable_node_dup, - struct stable_node **_stable_node, +static struct page *__stable_node_chain(struct ksm_stable_node **_stable_node_dup, + struct ksm_stable_node **_stable_node, struct rb_root *root, bool prune_stale_stable_nodes) { - struct stable_node *stable_node = *_stable_node; + struct ksm_stable_node *stable_node = *_stable_node; if (!is_stable_node_chain(stable_node)) { if (is_page_sharing_candidate(stable_node)) { *_stable_node_dup = stable_node; @@ -1541,18 +1541,18 @@ static struct page *__stable_node_chain(struct stable_node **_stable_node_dup, prune_stale_stable_nodes); } -static __always_inline struct page *chain_prune(struct stable_node **s_n_d, - struct stable_node **s_n, +static __always_inline struct page *chain_prune(struct ksm_stable_node **s_n_d, + struct ksm_stable_node **s_n, struct rb_root *root) { return __stable_node_chain(s_n_d, s_n, root, true); } -static __always_inline struct page *chain(struct stable_node **s_n_d, - struct stable_node *s_n, +static __always_inline struct page *chain(struct ksm_stable_node **s_n_d, + struct ksm_stable_node *s_n, struct rb_root *root) { - struct stable_node *old_stable_node = s_n; + struct ksm_stable_node *old_stable_node = s_n; struct page *tree_page; tree_page = __stable_node_chain(s_n_d, &s_n, root, false); @@ -1576,8 +1576,8 @@ static struct page *stable_tree_search(struct page *page) struct rb_root *root; struct rb_node **new; struct rb_node *parent; - struct stable_node *stable_node, *stable_node_dup, *stable_node_any; - struct stable_node *page_node; + struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any; + struct ksm_stable_node *page_node; page_node = page_stable_node(page); if (page_node && page_node->head != &migrate_nodes) { @@ -1597,7 +1597,7 @@ again: int ret; cond_resched(); - stable_node = rb_entry(*new, struct stable_node, node); + stable_node = rb_entry(*new, struct ksm_stable_node, node); stable_node_any = NULL; tree_page = chain_prune(&stable_node_dup, &stable_node, root); /* @@ -1820,14 +1820,14 @@ chain_append: * This function returns the stable tree node just allocated on success, * NULL otherwise. */ -static struct stable_node *stable_tree_insert(struct page *kpage) +static struct ksm_stable_node *stable_tree_insert(struct page *kpage) { int nid; unsigned long kpfn; struct rb_root *root; struct rb_node **new; struct rb_node *parent; - struct stable_node *stable_node, *stable_node_dup, *stable_node_any; + struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any; bool need_chain = false; kpfn = page_to_pfn(kpage); @@ -1842,7 +1842,7 @@ again: int ret; cond_resched(); - stable_node = rb_entry(*new, struct stable_node, node); + stable_node = rb_entry(*new, struct ksm_stable_node, node); stable_node_any = NULL; tree_page = chain(&stable_node_dup, stable_node, root); if (!stable_node_dup) { @@ -1911,7 +1911,7 @@ again: rb_insert_color(&stable_node_dup->node, root); } else { if (!is_stable_node_chain(stable_node)) { - struct stable_node *orig = stable_node; + struct ksm_stable_node *orig = stable_node; /* chain is missing so create it */ stable_node = alloc_stable_node_chain(orig, root); if (!stable_node) { @@ -1940,7 +1940,7 @@ again: * the same walking algorithm in an rbtree. */ static -struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, +struct ksm_rmap_item *unstable_tree_search_insert(struct ksm_rmap_item *rmap_item, struct page *page, struct page **tree_pagep) { @@ -1954,12 +1954,12 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, new = &root->rb_node; while (*new) { - struct rmap_item *tree_rmap_item; + struct ksm_rmap_item *tree_rmap_item; struct page *tree_page; int ret; cond_resched(); - tree_rmap_item = rb_entry(*new, struct rmap_item, node); + tree_rmap_item = rb_entry(*new, struct ksm_rmap_item, node); tree_page = get_mergeable_page(tree_rmap_item); if (!tree_page) return NULL; @@ -2011,8 +2011,8 @@ struct rmap_item *unstable_tree_search_insert(struct rmap_item *rmap_item, * rmap_items hanging off a given node of the stable tree, all sharing * the same ksm page. */ -static void stable_tree_append(struct rmap_item *rmap_item, - struct stable_node *stable_node, +static void stable_tree_append(struct ksm_rmap_item *rmap_item, + struct ksm_stable_node *stable_node, bool max_page_sharing_bypass) { /* @@ -2054,12 +2054,12 @@ static void stable_tree_append(struct rmap_item *rmap_item, * @page: the page that we are searching identical page to. * @rmap_item: the reverse mapping into the virtual address of this page */ -static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item) +static void cmp_and_merge_page(struct page *page, struct ksm_rmap_item *rmap_item) { struct mm_struct *mm = rmap_item->mm; - struct rmap_item *tree_rmap_item; + struct ksm_rmap_item *tree_rmap_item; struct page *tree_page = NULL; - struct stable_node *stable_node; + struct ksm_stable_node *stable_node; struct page *kpage; unsigned int checksum; int err; @@ -2215,11 +2215,11 @@ static void cmp_and_merge_page(struct page *page, struct rmap_item *rmap_item) } } -static struct rmap_item *get_next_rmap_item(struct mm_slot *mm_slot, - struct rmap_item **rmap_list, +static struct ksm_rmap_item *get_next_rmap_item(struct ksm_mm_slot *mm_slot, + struct ksm_rmap_item **rmap_list, unsigned long addr) { - struct rmap_item *rmap_item; + struct ksm_rmap_item *rmap_item; while (*rmap_list) { rmap_item = *rmap_list; @@ -2244,12 +2244,12 @@ static struct rmap_item *get_next_rmap_item(struct mm_slot *mm_slot, return rmap_item; } -static struct rmap_item *scan_get_next_rmap_item(struct page **page) +static struct ksm_rmap_item *scan_get_next_rmap_item(struct page **page) { struct mm_struct *mm; - struct mm_slot *slot; + struct ksm_mm_slot *slot; struct vm_area_struct *vma; - struct rmap_item *rmap_item; + struct ksm_rmap_item *rmap_item; struct vma_iterator vmi; int nid; @@ -2277,7 +2277,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) * so prune them once before each full scan. */ if (!ksm_merge_across_nodes) { - struct stable_node *stable_node, *next; + struct ksm_stable_node *stable_node, *next; struct page *page; list_for_each_entry_safe(stable_node, next, @@ -2294,7 +2294,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) root_unstable_tree[nid] = RB_ROOT; spin_lock(&ksm_mmlist_lock); - slot = list_entry(slot->mm_list.next, struct mm_slot, mm_list); + slot = list_entry(slot->mm_list.next, struct ksm_mm_slot, mm_list); ksm_scan.mm_slot = slot; spin_unlock(&ksm_mmlist_lock); /* @@ -2368,7 +2368,7 @@ no_vmas: spin_lock(&ksm_mmlist_lock); ksm_scan.mm_slot = list_entry(slot->mm_list.next, - struct mm_slot, mm_list); + struct ksm_mm_slot, mm_list); if (ksm_scan.address == 0) { /* * We've completed a full scan of all vmas, holding mmap_lock @@ -2414,7 +2414,7 @@ no_vmas: */ static void ksm_do_scan(unsigned int scan_npages) { - struct rmap_item *rmap_item; + struct ksm_rmap_item *rmap_item; struct page *page; while (scan_npages-- && likely(!freezing(current))) { @@ -2518,7 +2518,7 @@ EXPORT_SYMBOL_GPL(ksm_madvise); int __ksm_enter(struct mm_struct *mm) { - struct mm_slot *mm_slot; + struct ksm_mm_slot *mm_slot; int needs_wakeup; mm_slot = alloc_mm_slot(); @@ -2557,7 +2557,7 @@ int __ksm_enter(struct mm_struct *mm) void __ksm_exit(struct mm_struct *mm) { - struct mm_slot *mm_slot; + struct ksm_mm_slot *mm_slot; int easy_to_free = 0; /* @@ -2635,8 +2635,8 @@ struct page *ksm_might_need_to_copy(struct page *page, void rmap_walk_ksm(struct folio *folio, struct rmap_walk_control *rwc) { - struct stable_node *stable_node; - struct rmap_item *rmap_item; + struct ksm_stable_node *stable_node; + struct ksm_rmap_item *rmap_item; int search_new_forks = 0; VM_BUG_ON_FOLIO(!folio_test_ksm(folio), folio); @@ -2706,7 +2706,7 @@ again: #ifdef CONFIG_MIGRATION void folio_migrate_ksm(struct folio *newfolio, struct folio *folio) { - struct stable_node *stable_node; + struct ksm_stable_node *stable_node; VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); VM_BUG_ON_FOLIO(!folio_test_locked(newfolio), newfolio); @@ -2739,7 +2739,7 @@ static void wait_while_offlining(void) } } -static bool stable_node_dup_remove_range(struct stable_node *stable_node, +static bool stable_node_dup_remove_range(struct ksm_stable_node *stable_node, unsigned long start_pfn, unsigned long end_pfn) { @@ -2755,12 +2755,12 @@ static bool stable_node_dup_remove_range(struct stable_node *stable_node, return false; } -static bool stable_node_chain_remove_range(struct stable_node *stable_node, +static bool stable_node_chain_remove_range(struct ksm_stable_node *stable_node, unsigned long start_pfn, unsigned long end_pfn, struct rb_root *root) { - struct stable_node *dup; + struct ksm_stable_node *dup; struct hlist_node *hlist_safe; if (!is_stable_node_chain(stable_node)) { @@ -2784,14 +2784,14 @@ static bool stable_node_chain_remove_range(struct stable_node *stable_node, static void ksm_check_stable_tree(unsigned long start_pfn, unsigned long end_pfn) { - struct stable_node *stable_node, *next; + struct ksm_stable_node *stable_node, *next; struct rb_node *node; int nid; for (nid = 0; nid < ksm_nr_node_ids; nid++) { node = rb_first(root_stable_tree + nid); while (node) { - stable_node = rb_entry(node, struct stable_node, node); + stable_node = rb_entry(node, struct ksm_stable_node, node); if (stable_node_chain_remove_range(stable_node, start_pfn, end_pfn, root_stable_tree + -- cgit v1.2.3 From 7ebfce33125100e3f0c5e059845a019a1401433d Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Mon, 5 Sep 2022 23:05:46 +0200 Subject: kasan: support kasan.stacktrace for SW_TAGS Add support for the kasan.stacktrace command-line argument for Software Tag-Based KASAN. The following patch adds a command-line argument for selecting the stack ring size, and, as the stack ring is supported by both the Software and the Hardware Tag-Based KASAN modes, it is natural that both of them have support for kasan.stacktrace too. Link: https://lkml.kernel.org/r/3b43059103faa7f8796017847b7d674b658f11b5.1662411799.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Reviewed-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Peter Collingbourne Signed-off-by: Andrew Morton --- Documentation/dev-tools/kasan.rst | 15 ++++++++------ mm/kasan/hw_tags.c | 39 +---------------------------------- mm/kasan/kasan.h | 36 +++++++++++++++++++++----------- mm/kasan/sw_tags.c | 5 ++++- mm/kasan/tags.c | 43 +++++++++++++++++++++++++++++++++++++++ 5 files changed, 81 insertions(+), 57 deletions(-) (limited to 'Documentation') diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 1772fd457fed..7bd38c181018 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -111,9 +111,15 @@ parameter can be used to control panic and reporting behaviour: report or also panic the kernel (default: ``report``). The panic happens even if ``kasan_multi_shot`` is enabled. -Hardware Tag-Based KASAN mode (see the section about various modes below) is -intended for use in production as a security mitigation. Therefore, it supports -additional boot parameters that allow disabling KASAN or controlling features: +Software and Hardware Tag-Based KASAN modes (see the section about various +modes below) support disabling stack trace collection: + +- ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack + traces collection (default: ``on``). + +Hardware Tag-Based KASAN mode is intended for use in production as a security +mitigation. Therefore, it supports additional boot parameters that allow +disabling KASAN altogether or controlling its features: - ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``). @@ -132,9 +138,6 @@ additional boot parameters that allow disabling KASAN or controlling features: - ``kasan.vmalloc=off`` or ``=on`` disables or enables tagging of vmalloc allocations (default: ``on``). -- ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack - traces collection (default: ``on``). - Error reports ~~~~~~~~~~~~~ diff --git a/mm/kasan/hw_tags.c b/mm/kasan/hw_tags.c index 9ad8eff71b28..b22c4f461cb0 100644 --- a/mm/kasan/hw_tags.c +++ b/mm/kasan/hw_tags.c @@ -38,16 +38,9 @@ enum kasan_arg_vmalloc { KASAN_ARG_VMALLOC_ON, }; -enum kasan_arg_stacktrace { - KASAN_ARG_STACKTRACE_DEFAULT, - KASAN_ARG_STACKTRACE_OFF, - KASAN_ARG_STACKTRACE_ON, -}; - static enum kasan_arg kasan_arg __ro_after_init; static enum kasan_arg_mode kasan_arg_mode __ro_after_init; static enum kasan_arg_vmalloc kasan_arg_vmalloc __initdata; -static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata; /* * Whether KASAN is enabled at all. @@ -66,9 +59,6 @@ EXPORT_SYMBOL_GPL(kasan_mode); /* Whether to enable vmalloc tagging. */ DEFINE_STATIC_KEY_TRUE(kasan_flag_vmalloc); -/* Whether to collect alloc/free stack traces. */ -DEFINE_STATIC_KEY_TRUE(kasan_flag_stacktrace); - /* kasan=off/on */ static int __init early_kasan_flag(char *arg) { @@ -122,23 +112,6 @@ static int __init early_kasan_flag_vmalloc(char *arg) } early_param("kasan.vmalloc", early_kasan_flag_vmalloc); -/* kasan.stacktrace=off/on */ -static int __init early_kasan_flag_stacktrace(char *arg) -{ - if (!arg) - return -EINVAL; - - if (!strcmp(arg, "off")) - kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF; - else if (!strcmp(arg, "on")) - kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON; - else - return -EINVAL; - - return 0; -} -early_param("kasan.stacktrace", early_kasan_flag_stacktrace); - static inline const char *kasan_mode_info(void) { if (kasan_mode == KASAN_MODE_ASYNC) @@ -213,17 +186,7 @@ void __init kasan_init_hw_tags(void) break; } - switch (kasan_arg_stacktrace) { - case KASAN_ARG_STACKTRACE_DEFAULT: - /* Default is specified by kasan_flag_stacktrace definition. */ - break; - case KASAN_ARG_STACKTRACE_OFF: - static_branch_disable(&kasan_flag_stacktrace); - break; - case KASAN_ARG_STACKTRACE_ON: - static_branch_enable(&kasan_flag_stacktrace); - break; - } + kasan_init_tags(); /* KASAN is now initialized, enable it. */ static_branch_enable(&kasan_flag_enabled); diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index cfff81139d67..447baf1a7a2e 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -8,13 +8,31 @@ #include #include -#ifdef CONFIG_KASAN_HW_TAGS +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) #include + +DECLARE_STATIC_KEY_TRUE(kasan_flag_stacktrace); + +static inline bool kasan_stack_collection_enabled(void) +{ + return static_branch_unlikely(&kasan_flag_stacktrace); +} + +#else /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ + +static inline bool kasan_stack_collection_enabled(void) +{ + return true; +} + +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ + +#ifdef CONFIG_KASAN_HW_TAGS + #include "../slab.h" DECLARE_STATIC_KEY_TRUE(kasan_flag_vmalloc); -DECLARE_STATIC_KEY_TRUE(kasan_flag_stacktrace); enum kasan_mode { KASAN_MODE_SYNC, @@ -29,11 +47,6 @@ static inline bool kasan_vmalloc_enabled(void) return static_branch_likely(&kasan_flag_vmalloc); } -static inline bool kasan_stack_collection_enabled(void) -{ - return static_branch_unlikely(&kasan_flag_stacktrace); -} - static inline bool kasan_async_fault_possible(void) { return kasan_mode == KASAN_MODE_ASYNC || kasan_mode == KASAN_MODE_ASYMM; @@ -46,11 +59,6 @@ static inline bool kasan_sync_fault_possible(void) #else /* CONFIG_KASAN_HW_TAGS */ -static inline bool kasan_stack_collection_enabled(void) -{ - return true; -} - static inline bool kasan_async_fault_possible(void) { return false; @@ -410,6 +418,10 @@ static inline void kasan_enable_tagging(void) { } #endif /* CONFIG_KASAN_HW_TAGS */ +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS) +void __init kasan_init_tags(void); +#endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ + #if defined(CONFIG_KASAN_HW_TAGS) && IS_ENABLED(CONFIG_KASAN_KUNIT_TEST) void kasan_force_async_fault(void); diff --git a/mm/kasan/sw_tags.c b/mm/kasan/sw_tags.c index 77f13f391b57..a3afaf2ad1b1 100644 --- a/mm/kasan/sw_tags.c +++ b/mm/kasan/sw_tags.c @@ -42,7 +42,10 @@ void __init kasan_init_sw_tags(void) for_each_possible_cpu(cpu) per_cpu(prng_state, cpu) = (u32)get_cycles(); - pr_info("KernelAddressSanitizer initialized (sw-tags)\n"); + kasan_init_tags(); + + pr_info("KernelAddressSanitizer initialized (sw-tags, stacktrace=%s)\n", + kasan_stack_collection_enabled() ? "on" : "off"); } /* diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index a0524e037f49..dd929ab166fb 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -19,6 +19,17 @@ #include "kasan.h" #include "../slab.h" +enum kasan_arg_stacktrace { + KASAN_ARG_STACKTRACE_DEFAULT, + KASAN_ARG_STACKTRACE_OFF, + KASAN_ARG_STACKTRACE_ON, +}; + +static enum kasan_arg_stacktrace kasan_arg_stacktrace __initdata; + +/* Whether to collect alloc/free stack traces. */ +DEFINE_STATIC_KEY_TRUE(kasan_flag_stacktrace); + /* Non-zero, as initial pointer values are 0. */ #define STACK_RING_BUSY_PTR ((void *)1) @@ -26,6 +37,38 @@ struct kasan_stack_ring stack_ring = { .lock = __RW_LOCK_UNLOCKED(stack_ring.lock) }; +/* kasan.stacktrace=off/on */ +static int __init early_kasan_flag_stacktrace(char *arg) +{ + if (!arg) + return -EINVAL; + + if (!strcmp(arg, "off")) + kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_OFF; + else if (!strcmp(arg, "on")) + kasan_arg_stacktrace = KASAN_ARG_STACKTRACE_ON; + else + return -EINVAL; + + return 0; +} +early_param("kasan.stacktrace", early_kasan_flag_stacktrace); + +void __init kasan_init_tags(void) +{ + switch (kasan_arg_stacktrace) { + case KASAN_ARG_STACKTRACE_DEFAULT: + /* Default is specified by kasan_flag_stacktrace definition. */ + break; + case KASAN_ARG_STACKTRACE_OFF: + static_branch_disable(&kasan_flag_stacktrace); + break; + case KASAN_ARG_STACKTRACE_ON: + static_branch_enable(&kasan_flag_stacktrace); + break; + } +} + static void save_stack_info(struct kmem_cache *cache, void *object, gfp_t gfp_flags, bool is_free) { -- cgit v1.2.3 From 80b92bfe3bb75aa6688f58af9df356757a46f659 Mon Sep 17 00:00:00 2001 From: Andrey Konovalov Date: Mon, 5 Sep 2022 23:05:47 +0200 Subject: kasan: dynamically allocate stack ring entries Instead of using a large static array, allocate the stack ring dynamically via memblock_alloc(). The size of the stack ring is controlled by a new kasan.stack_ring_size command-line parameter. When kasan.stack_ring_size is not provided, the default value of 32 << 10 is used. When the stack trace collection is disabled via kasan.stacktrace=off, the stack ring is not allocated. Link: https://lkml.kernel.org/r/03b82ab60db53427e9818e0b0c1971baa10c3cbc.1662411800.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov Acked-by: Marco Elver Cc: Alexander Potapenko Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Evgenii Stepanov Cc: Peter Collingbourne Signed-off-by: Andrew Morton --- Documentation/dev-tools/kasan.rst | 4 +++- mm/kasan/kasan.h | 5 ++--- mm/kasan/report_tags.c | 4 ++-- mm/kasan/tags.c | 25 ++++++++++++++++++++++++- 4 files changed, 31 insertions(+), 7 deletions(-) (limited to 'Documentation') diff --git a/Documentation/dev-tools/kasan.rst b/Documentation/dev-tools/kasan.rst index 7bd38c181018..5c93ab915049 100644 --- a/Documentation/dev-tools/kasan.rst +++ b/Documentation/dev-tools/kasan.rst @@ -112,10 +112,12 @@ parameter can be used to control panic and reporting behaviour: if ``kasan_multi_shot`` is enabled. Software and Hardware Tag-Based KASAN modes (see the section about various -modes below) support disabling stack trace collection: +modes below) support altering stack trace collection behavior: - ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack traces collection (default: ``on``). +- ``kasan.stack_ring_size=`` specifies the number of entries + in the stack ring (default: ``32768``). Hardware Tag-Based KASAN mode is intended for use in production as a security mitigation. Therefore, it supports additional boot parameters that allow diff --git a/mm/kasan/kasan.h b/mm/kasan/kasan.h index 447baf1a7a2e..abbcc1b0eec5 100644 --- a/mm/kasan/kasan.h +++ b/mm/kasan/kasan.h @@ -252,12 +252,11 @@ struct kasan_stack_ring_entry { bool is_free; }; -#define KASAN_STACK_RING_SIZE (32 << 10) - struct kasan_stack_ring { rwlock_t lock; + size_t size; atomic64_t pos; - struct kasan_stack_ring_entry entries[KASAN_STACK_RING_SIZE]; + struct kasan_stack_ring_entry *entries; }; #endif /* CONFIG_KASAN_SW_TAGS || CONFIG_KASAN_HW_TAGS */ diff --git a/mm/kasan/report_tags.c b/mm/kasan/report_tags.c index 1b78136542bb..57f7355377f1 100644 --- a/mm/kasan/report_tags.c +++ b/mm/kasan/report_tags.c @@ -56,11 +56,11 @@ void kasan_complete_mode_report_info(struct kasan_report_info *info) * entries relevant to the buggy object can be overwritten. */ - for (u64 i = pos - 1; i != pos - 1 - KASAN_STACK_RING_SIZE; i--) { + for (u64 i = pos - 1; i != pos - 1 - stack_ring.size; i--) { if (alloc_found && free_found) break; - entry = &stack_ring.entries[i % KASAN_STACK_RING_SIZE]; + entry = &stack_ring.entries[i % stack_ring.size]; /* Paired with smp_store_release() in save_stack_info(). */ ptr = (void *)smp_load_acquire(&entry->ptr); diff --git a/mm/kasan/tags.c b/mm/kasan/tags.c index dd929ab166fb..67a222586846 100644 --- a/mm/kasan/tags.c +++ b/mm/kasan/tags.c @@ -10,6 +10,7 @@ #include #include #include +#include #include #include #include @@ -19,6 +20,8 @@ #include "kasan.h" #include "../slab.h" +#define KASAN_STACK_RING_SIZE_DEFAULT (32 << 10) + enum kasan_arg_stacktrace { KASAN_ARG_STACKTRACE_DEFAULT, KASAN_ARG_STACKTRACE_OFF, @@ -54,6 +57,16 @@ static int __init early_kasan_flag_stacktrace(char *arg) } early_param("kasan.stacktrace", early_kasan_flag_stacktrace); +/* kasan.stack_ring_size= */ +static int __init early_kasan_flag_stack_ring_size(char *arg) +{ + if (!arg) + return -EINVAL; + + return kstrtoul(arg, 0, &stack_ring.size); +} +early_param("kasan.stack_ring_size", early_kasan_flag_stack_ring_size); + void __init kasan_init_tags(void) { switch (kasan_arg_stacktrace) { @@ -67,6 +80,16 @@ void __init kasan_init_tags(void) static_branch_enable(&kasan_flag_stacktrace); break; } + + if (kasan_stack_collection_enabled()) { + if (!stack_ring.size) + stack_ring.size = KASAN_STACK_RING_SIZE_DEFAULT; + stack_ring.entries = memblock_alloc( + sizeof(stack_ring.entries[0]) * stack_ring.size, + SMP_CACHE_BYTES); + if (WARN_ON(!stack_ring.entries)) + static_branch_disable(&kasan_flag_stacktrace); + } } static void save_stack_info(struct kmem_cache *cache, void *object, @@ -88,7 +111,7 @@ static void save_stack_info(struct kmem_cache *cache, void *object, next: pos = atomic64_fetch_add(1, &stack_ring.pos); - entry = &stack_ring.entries[pos % KASAN_STACK_RING_SIZE]; + entry = &stack_ring.entries[pos % stack_ring.size]; /* Detect stack ring entry slots that are being written to. */ old_ptr = READ_ONCE(entry->ptr); -- cgit v1.2.3 From 0ff11f103f5d9daf14dddf05de9b12611eaf3fc1 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 9 Sep 2022 20:28:58 +0000 Subject: Docs/admin-guide/mm/damon: rename the title of the document The title of the DAMON document for admin-guide, 'Monitoring Data Accesses', could confuse readers in some ways. First of all, DAMON is not the only single way for data access monitoring. And the document is for not only the data access monitoring but also data access pattern based memory management optimizations (DAMOS). This commit updates the title to 'DAMON: Data Access MONitor', which more explicitly explains what the document describes. Link: https://lkml.kernel.org/r/20220909202901.57977-5-sj@kernel.org Fixes: c4ba6014aec3 ("Documentation: add documents for DAMON") Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: Jonathan Corbet Cc: Shuah Khan Cc: Yun Levi Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/damon/index.rst | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/damon/index.rst b/Documentation/admin-guide/mm/damon/index.rst index 05500042f777..33d37bb2fb4e 100644 --- a/Documentation/admin-guide/mm/damon/index.rst +++ b/Documentation/admin-guide/mm/damon/index.rst @@ -1,8 +1,8 @@ .. SPDX-License-Identifier: GPL-2.0 -======================== -Monitoring Data Accesses -======================== +========================== +DAMON: Data Access MONitor +========================== :doc:`DAMON ` allows light-weight data access monitoring. Using DAMON, users can analyze the memory access patterns of their systems and -- cgit v1.2.3 From 04cc7e4bf7c4bdff24b62432d2beafdde60cb72b Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 9 Sep 2022 20:29:00 +0000 Subject: Docs/admin-guide/mm/damon/start: mention the dependency as sysfs instead of debugfs 'Getting Started' document of DAMON says DAMON user-space tool, damo[1], is using DAMON debugfs interface, and therefore it needs to ensure debugfs is mounted. However, the latest version of the tool is using DAMON sysfs interface. Moreover, DAMON debugfs interface is going to be deprecated as announced by commit b18402726bd1 ("Docs/admin-guide/mm/damon/usage: document DAMON sysfs interface"). This commit therefore update the document to tell readers about DAMON sysfs interface dependency instead and never mention about debugfs interface, which will be deprecated. [1] https://github.com/awslabs/damo Link: https://lkml.kernel.org/r/20220909202901.57977-7-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: Jonathan Corbet Cc: Shuah Khan Cc: Yun Levi Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/damon/start.rst | 13 +++---------- 1 file changed, 3 insertions(+), 10 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/damon/start.rst b/Documentation/admin-guide/mm/damon/start.rst index 4d5ca2c46288..9f88afc734da 100644 --- a/Documentation/admin-guide/mm/damon/start.rst +++ b/Documentation/admin-guide/mm/damon/start.rst @@ -29,16 +29,9 @@ called DAMON Operator (DAMO). It is available at https://github.com/awslabs/damo. The examples below assume that ``damo`` is on your ``$PATH``. It's not mandatory, though. -Because DAMO is using the debugfs interface (refer to :doc:`usage` for the -detail) of DAMON, you should ensure debugfs is mounted. Mount it manually as -below:: - - # mount -t debugfs none /sys/kernel/debug/ - -or append the following line to your ``/etc/fstab`` file so that your system -can automatically mount debugfs upon booting:: - - debugfs /sys/kernel/debug debugfs defaults 0 0 +Because DAMO is using the sysfs interface (refer to :doc:`usage` for the +detail) of DAMON, you should ensure :doc:`sysfs ` is +mounted. Recording Data Access Patterns -- cgit v1.2.3 From f1f3afd59d78db163f6655394980290c1bdf9eab Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 9 Sep 2022 20:29:01 +0000 Subject: Docs/admin-guide/mm/damon/usage: note DAMON debugfs interface deprecation plan Commit b18402726bd1 ("Docs/admin-guide/mm/damon/usage: document DAMON sysfs interface") announced the DAMON debugfs interface deprecation plan, but it is not so aggressively announced. As the deprecation time is coming, this commit makes the announce more easy to be found by adding the note at the beginning of the DAMON debugfs interface usage document. Link: https://lkml.kernel.org/r/20220909202901.57977-8-sj@kernel.org Signed-off-by: SeongJae Park Cc: Brendan Higgins Cc: Jonathan Corbet Cc: Shuah Khan Cc: Yun Levi Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/damon/usage.rst | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/damon/usage.rst b/Documentation/admin-guide/mm/damon/usage.rst index d52f572a9029..c050b882ddc1 100644 --- a/Documentation/admin-guide/mm/damon/usage.rst +++ b/Documentation/admin-guide/mm/damon/usage.rst @@ -393,6 +393,11 @@ the files as above. Above is only for an example. debugfs Interface ================= +.. note:: + + DAMON debugfs interface will be removed after next LTS kernel is released, so + users should move to the :ref:`sysfs interface `. + DAMON exports eight files, ``attrs``, ``target_ids``, ``init_regions``, ``schemes``, ``monitor_on``, ``kdamond_pid``, ``mk_contexts`` and ``rm_contexts`` under its debugfs directory, ``/damon/``. -- cgit v1.2.3 From f4981502088f8ea704beeedf3470e1d53bc2e46c Mon Sep 17 00:00:00 2001 From: Liu Shixin Date: Fri, 9 Sep 2022 10:16:53 +0800 Subject: mm/huge_memory: prevent THP_ZERO_PAGE_ALLOC increased twice A user who reads THP_ZERO_PAGE_ALLOC may be more concerned about the huge zero pages that are really allocated for thp. It is misleading to increase THP_ZERO_PAGE_ALLOC twice if two threads call get_huge_zero_page concurrently. Don't increase the value if the huge page is not really used. Update Documentation/admin-guide/mm/transhuge.rst to suit. Link: https://lkml.kernel.org/r/20220909021653.3371879-1-liushixin2@huawei.com Signed-off-by: Liu Shixin Cc: Alexander Potapenko Cc: Vlastimil Babka Cc: Andrea Arcangeli Cc: Kefeng Wang Cc: "Kirill A. Shutemov" Cc: Mike Kravetz Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/transhuge.rst | 7 +++---- mm/huge_memory.c | 2 +- 2 files changed, 4 insertions(+), 5 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index c9c37f16eef8..8e3418ec4503 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -366,10 +366,9 @@ thp_split_pmd page table entry. thp_zero_page_alloc - is incremented every time a huge zero page is - successfully allocated. It includes allocations which where - dropped due race with other allocation. Note, it doesn't count - every map of the huge zero page, only its allocation. + is incremented every time a huge zero page used for thp is + successfully allocated. Note, it doesn't count every map of + the huge zero page, only its allocation. thp_zero_page_alloc_failed is incremented if kernel fails to allocate diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 36ef79b85195..4938defe4e73 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -163,7 +163,6 @@ retry: count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED); return false; } - count_vm_event(THP_ZERO_PAGE_ALLOC); preempt_disable(); if (cmpxchg(&huge_zero_page, NULL, zero_page)) { preempt_enable(); @@ -175,6 +174,7 @@ retry: /* We take additional reference here. It will be put back by shrinker */ atomic_set(&huge_zero_refcount, 2); preempt_enable(); + count_vm_event(THP_ZERO_PAGE_ALLOC); return true; } -- cgit v1.2.3 From 93858ae70cf4fb2ec75ae2f1e495b85b26614883 Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Thu, 15 Sep 2022 17:03:40 +0200 Subject: kmsan: add ReST documentation Add Documentation/dev-tools/kmsan.rst and reference it in the dev-tools index. Link: https://lkml.kernel.org/r/20220915150417.722975-7-glider@google.com Signed-off-by: Alexander Potapenko Cc: Alexander Viro Cc: Alexei Starovoitov Cc: Andrey Konovalov Cc: Andrey Konovalov Cc: Andy Lutomirski Cc: Arnd Bergmann Cc: Borislav Petkov Cc: Christoph Hellwig Cc: Christoph Lameter Cc: David Rientjes Cc: Dmitry Vyukov Cc: Eric Biggers Cc: Eric Biggers Cc: Eric Dumazet Cc: Greg Kroah-Hartman Cc: Herbert Xu Cc: Ilya Leoshkevich Cc: Ingo Molnar Cc: Jens Axboe Cc: Joonsoo Kim Cc: Kees Cook Cc: Marco Elver Cc: Mark Rutland Cc: Matthew Wilcox Cc: Michael S. Tsirkin Cc: Pekka Enberg Cc: Peter Zijlstra Cc: Petr Mladek Cc: Stephen Rothwell Cc: Steven Rostedt Cc: Thomas Gleixner Cc: Vasily Gorbik Cc: Vegard Nossum Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- Documentation/dev-tools/index.rst | 1 + Documentation/dev-tools/kmsan.rst | 427 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 428 insertions(+) create mode 100644 Documentation/dev-tools/kmsan.rst (limited to 'Documentation') diff --git a/Documentation/dev-tools/index.rst b/Documentation/dev-tools/index.rst index 4621eac290f4..6b0663075dc0 100644 --- a/Documentation/dev-tools/index.rst +++ b/Documentation/dev-tools/index.rst @@ -24,6 +24,7 @@ Documentation/dev-tools/testing-overview.rst kcov gcov kasan + kmsan ubsan kmemleak kcsan diff --git a/Documentation/dev-tools/kmsan.rst b/Documentation/dev-tools/kmsan.rst new file mode 100644 index 000000000000..2a53a801198c --- /dev/null +++ b/Documentation/dev-tools/kmsan.rst @@ -0,0 +1,427 @@ +.. SPDX-License-Identifier: GPL-2.0 +.. Copyright (C) 2022, Google LLC. + +=================================== +The Kernel Memory Sanitizer (KMSAN) +=================================== + +KMSAN is a dynamic error detector aimed at finding uses of uninitialized +values. It is based on compiler instrumentation, and is quite similar to the +userspace `MemorySanitizer tool`_. + +An important note is that KMSAN is not intended for production use, because it +drastically increases kernel memory footprint and slows the whole system down. + +Usage +===== + +Building the kernel +------------------- + +In order to build a kernel with KMSAN you will need a fresh Clang (14.0.6+). +Please refer to `LLVM documentation`_ for the instructions on how to build Clang. + +Now configure and build the kernel with CONFIG_KMSAN enabled. + +Example report +-------------- + +Here is an example of a KMSAN report:: + + ===================================================== + BUG: KMSAN: uninit-value in test_uninit_kmsan_check_memory+0x1be/0x380 [kmsan_test] + test_uninit_kmsan_check_memory+0x1be/0x380 mm/kmsan/kmsan_test.c:273 + kunit_run_case_internal lib/kunit/test.c:333 + kunit_try_run_case+0x206/0x420 lib/kunit/test.c:374 + kunit_generic_run_threadfn_adapter+0x6d/0xc0 lib/kunit/try-catch.c:28 + kthread+0x721/0x850 kernel/kthread.c:327 + ret_from_fork+0x1f/0x30 ??:? + + Uninit was stored to memory at: + do_uninit_local_array+0xfa/0x110 mm/kmsan/kmsan_test.c:260 + test_uninit_kmsan_check_memory+0x1a2/0x380 mm/kmsan/kmsan_test.c:271 + kunit_run_case_internal lib/kunit/test.c:333 + kunit_try_run_case+0x206/0x420 lib/kunit/test.c:374 + kunit_generic_run_threadfn_adapter+0x6d/0xc0 lib/kunit/try-catch.c:28 + kthread+0x721/0x850 kernel/kthread.c:327 + ret_from_fork+0x1f/0x30 ??:? + + Local variable uninit created at: + do_uninit_local_array+0x4a/0x110 mm/kmsan/kmsan_test.c:256 + test_uninit_kmsan_check_memory+0x1a2/0x380 mm/kmsan/kmsan_test.c:271 + + Bytes 4-7 of 8 are uninitialized + Memory access of size 8 starts at ffff888083fe3da0 + + CPU: 0 PID: 6731 Comm: kunit_try_catch Tainted: G B E 5.16.0-rc3+ #104 + Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 + ===================================================== + +The report says that the local variable ``uninit`` was created uninitialized in +``do_uninit_local_array()``. The third stack trace corresponds to the place +where this variable was created. + +The first stack trace shows where the uninit value was used (in +``test_uninit_kmsan_check_memory()``). The tool shows the bytes which were left +uninitialized in the local variable, as well as the stack where the value was +copied to another memory location before use. + +A use of uninitialized value ``v`` is reported by KMSAN in the following cases: + - in a condition, e.g. ``if (v) { ... }``; + - in an indexing or pointer dereferencing, e.g. ``array[v]`` or ``*v``; + - when it is copied to userspace or hardware, e.g. ``copy_to_user(..., &v, ...)``; + - when it is passed as an argument to a function, and + ``CONFIG_KMSAN_CHECK_PARAM_RETVAL`` is enabled (see below). + +The mentioned cases (apart from copying data to userspace or hardware, which is +a security issue) are considered undefined behavior from the C11 Standard point +of view. + +Disabling the instrumentation +----------------------------- + +A function can be marked with ``__no_kmsan_checks``. Doing so makes KMSAN +ignore uninitialized values in that function and mark its output as initialized. +As a result, the user will not get KMSAN reports related to that function. + +Another function attribute supported by KMSAN is ``__no_sanitize_memory``. +Applying this attribute to a function will result in KMSAN not instrumenting +it, which can be helpful if we do not want the compiler to interfere with some +low-level code (e.g. that marked with ``noinstr`` which implicitly adds +``__no_sanitize_memory``). + +This however comes at a cost: stack allocations from such functions will have +incorrect shadow/origin values, likely leading to false positives. Functions +called from non-instrumented code may also receive incorrect metadata for their +parameters. + +As a rule of thumb, avoid using ``__no_sanitize_memory`` explicitly. + +It is also possible to disable KMSAN for a single file (e.g. main.o):: + + KMSAN_SANITIZE_main.o := n + +or for the whole directory:: + + KMSAN_SANITIZE := n + +in the Makefile. Think of this as applying ``__no_sanitize_memory`` to every +function in the file or directory. Most users won't need KMSAN_SANITIZE, unless +their code gets broken by KMSAN (e.g. runs at early boot time). + +Support +======= + +In order for KMSAN to work the kernel must be built with Clang, which so far is +the only compiler that has KMSAN support. The kernel instrumentation pass is +based on the userspace `MemorySanitizer tool`_. + +The runtime library only supports x86_64 at the moment. + +How KMSAN works +=============== + +KMSAN shadow memory +------------------- + +KMSAN associates a metadata byte (also called shadow byte) with every byte of +kernel memory. A bit in the shadow byte is set iff the corresponding bit of the +kernel memory byte is uninitialized. Marking the memory uninitialized (i.e. +setting its shadow bytes to ``0xff``) is called poisoning, marking it +initialized (setting the shadow bytes to ``0x00``) is called unpoisoning. + +When a new variable is allocated on the stack, it is poisoned by default by +instrumentation code inserted by the compiler (unless it is a stack variable +that is immediately initialized). Any new heap allocation done without +``__GFP_ZERO`` is also poisoned. + +Compiler instrumentation also tracks the shadow values as they are used along +the code. When needed, instrumentation code invokes the runtime library in +``mm/kmsan/`` to persist shadow values. + +The shadow value of a basic or compound type is an array of bytes of the same +length. When a constant value is written into memory, that memory is unpoisoned. +When a value is read from memory, its shadow memory is also obtained and +propagated into all the operations which use that value. For every instruction +that takes one or more values the compiler generates code that calculates the +shadow of the result depending on those values and their shadows. + +Example:: + + int a = 0xff; // i.e. 0x000000ff + int b; + int c = a | b; + +In this case the shadow of ``a`` is ``0``, shadow of ``b`` is ``0xffffffff``, +shadow of ``c`` is ``0xffffff00``. This means that the upper three bytes of +``c`` are uninitialized, while the lower byte is initialized. + +Origin tracking +--------------- + +Every four bytes of kernel memory also have a so-called origin mapped to them. +This origin describes the point in program execution at which the uninitialized +value was created. Every origin is associated with either the full allocation +stack (for heap-allocated memory), or the function containing the uninitialized +variable (for locals). + +When an uninitialized variable is allocated on stack or heap, a new origin +value is created, and that variable's origin is filled with that value. When a +value is read from memory, its origin is also read and kept together with the +shadow. For every instruction that takes one or more values, the origin of the +result is one of the origins corresponding to any of the uninitialized inputs. +If a poisoned value is written into memory, its origin is written to the +corresponding storage as well. + +Example 1:: + + int a = 42; + int b; + int c = a + b; + +In this case the origin of ``b`` is generated upon function entry, and is +stored to the origin of ``c`` right before the addition result is written into +memory. + +Several variables may share the same origin address, if they are stored in the +same four-byte chunk. In this case every write to either variable updates the +origin for all of them. We have to sacrifice precision in this case, because +storing origins for individual bits (and even bytes) would be too costly. + +Example 2:: + + int combine(short a, short b) { + union ret_t { + int i; + short s[2]; + } ret; + ret.s[0] = a; + ret.s[1] = b; + return ret.i; + } + +If ``a`` is initialized and ``b`` is not, the shadow of the result would be +0xffff0000, and the origin of the result would be the origin of ``b``. +``ret.s[0]`` would have the same origin, but it will never be used, because +that variable is initialized. + +If both function arguments are uninitialized, only the origin of the second +argument is preserved. + +Origin chaining +~~~~~~~~~~~~~~~ + +To ease debugging, KMSAN creates a new origin for every store of an +uninitialized value to memory. The new origin references both its creation stack +and the previous origin the value had. This may cause increased memory +consumption, so we limit the length of origin chains in the runtime. + +Clang instrumentation API +------------------------- + +Clang instrumentation pass inserts calls to functions defined in +``mm/kmsan/nstrumentation.c`` into the kernel code. + +Shadow manipulation +~~~~~~~~~~~~~~~~~~~ + +For every memory access the compiler emits a call to a function that returns a +pair of pointers to the shadow and origin addresses of the given memory:: + + typedef struct { + void *shadow, *origin; + } shadow_origin_ptr_t + + shadow_origin_ptr_t __msan_metadata_ptr_for_load_{1,2,4,8}(void *addr) + shadow_origin_ptr_t __msan_metadata_ptr_for_store_{1,2,4,8}(void *addr) + shadow_origin_ptr_t __msan_metadata_ptr_for_load_n(void *addr, uintptr_t size) + shadow_origin_ptr_t __msan_metadata_ptr_for_store_n(void *addr, uintptr_t size) + +The function name depends on the memory access size. + +The compiler makes sure that for every loaded value its shadow and origin +values are read from memory. When a value is stored to memory, its shadow and +origin are also stored using the metadata pointers. + +Handling locals +~~~~~~~~~~~~~~~ + +A special function is used to create a new origin value for a local variable and +set the origin of that variable to that value:: + + void __msan_poison_alloca(void *addr, uintptr_t size, char *descr) + +Access to per-task data +~~~~~~~~~~~~~~~~~~~~~~~ + +At the beginning of every instrumented function KMSAN inserts a call to +``__msan_get_context_state()``:: + + kmsan_context_state *__msan_get_context_state(void) + +``kmsan_context_state`` is declared in ``include/linux/kmsan.h``:: + + struct kmsan_context_state { + char param_tls[KMSAN_PARAM_SIZE]; + char retval_tls[KMSAN_RETVAL_SIZE]; + char va_arg_tls[KMSAN_PARAM_SIZE]; + char va_arg_origin_tls[KMSAN_PARAM_SIZE]; + u64 va_arg_overflow_size_tls; + char param_origin_tls[KMSAN_PARAM_SIZE]; + depot_stack_handle_t retval_origin_tls; + }; + +This structure is used by KMSAN to pass parameter shadows and origins between +instrumented functions (unless the parameters are checked immediately by +``CONFIG_KMSAN_CHECK_PARAM_RETVAL``). + +Passing uninitialized values to functions +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +Clang's MemorySanitizer instrumentation has an option, +``-fsanitize-memory-param-retval``, which makes the compiler check function +parameters passed by value, as well as function return values. + +The option is controlled by ``CONFIG_KMSAN_CHECK_PARAM_RETVAL``, which is +enabled by default to let KMSAN report uninitialized values earlier. +Please refer to the `LKML discussion`_ for more details. + +Because of the way the checks are implemented in LLVM (they are only applied to +parameters marked as ``noundef``), not all parameters are guaranteed to be +checked, so we cannot give up the metadata storage in ``kmsan_context_state``. + +String functions +~~~~~~~~~~~~~~~~ + +The compiler replaces calls to ``memcpy()``/``memmove()``/``memset()`` with the +following functions. These functions are also called when data structures are +initialized or copied, making sure shadow and origin values are copied alongside +with the data:: + + void *__msan_memcpy(void *dst, void *src, uintptr_t n) + void *__msan_memmove(void *dst, void *src, uintptr_t n) + void *__msan_memset(void *dst, int c, uintptr_t n) + +Error reporting +~~~~~~~~~~~~~~~ + +For each use of a value the compiler emits a shadow check that calls +``__msan_warning()`` in the case that value is poisoned:: + + void __msan_warning(u32 origin) + +``__msan_warning()`` causes KMSAN runtime to print an error report. + +Inline assembly instrumentation +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +KMSAN instruments every inline assembly output with a call to:: + + void __msan_instrument_asm_store(void *addr, uintptr_t size) + +, which unpoisons the memory region. + +This approach may mask certain errors, but it also helps to avoid a lot of +false positives in bitwise operations, atomics etc. + +Sometimes the pointers passed into inline assembly do not point to valid memory. +In such cases they are ignored at runtime. + + +Runtime library +--------------- + +The code is located in ``mm/kmsan/``. + +Per-task KMSAN state +~~~~~~~~~~~~~~~~~~~~ + +Every task_struct has an associated KMSAN task state that holds the KMSAN +context (see above) and a per-task flag disallowing KMSAN reports:: + + struct kmsan_context { + ... + bool allow_reporting; + struct kmsan_context_state cstate; + ... + } + + struct task_struct { + ... + struct kmsan_context kmsan; + ... + } + +KMSAN contexts +~~~~~~~~~~~~~~ + +When running in a kernel task context, KMSAN uses ``current->kmsan.cstate`` to +hold the metadata for function parameters and return values. + +But in the case the kernel is running in the interrupt, softirq or NMI context, +where ``current`` is unavailable, KMSAN switches to per-cpu interrupt state:: + + DEFINE_PER_CPU(struct kmsan_ctx, kmsan_percpu_ctx); + +Metadata allocation +~~~~~~~~~~~~~~~~~~~ + +There are several places in the kernel for which the metadata is stored. + +1. Each ``struct page`` instance contains two pointers to its shadow and +origin pages:: + + struct page { + ... + struct page *shadow, *origin; + ... + }; + +At boot-time, the kernel allocates shadow and origin pages for every available +kernel page. This is done quite late, when the kernel address space is already +fragmented, so normal data pages may arbitrarily interleave with the metadata +pages. + +This means that in general for two contiguous memory pages their shadow/origin +pages may not be contiguous. Consequently, if a memory access crosses the +boundary of a memory block, accesses to shadow/origin memory may potentially +corrupt other pages or read incorrect values from them. + +In practice, contiguous memory pages returned by the same ``alloc_pages()`` +call will have contiguous metadata, whereas if these pages belong to two +different allocations their metadata pages can be fragmented. + +For the kernel data (``.data``, ``.bss`` etc.) and percpu memory regions +there also are no guarantees on metadata contiguity. + +In the case ``__msan_metadata_ptr_for_XXX_YYY()`` hits the border between two +pages with non-contiguous metadata, it returns pointers to fake shadow/origin regions:: + + char dummy_load_page[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE))); + char dummy_store_page[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE))); + +``dummy_load_page`` is zero-initialized, so reads from it always yield zeroes. +All stores to ``dummy_store_page`` are ignored. + +2. For vmalloc memory and modules, there is a direct mapping between the memory +range, its shadow and origin. KMSAN reduces the vmalloc area by 3/4, making only +the first quarter available to ``vmalloc()``. The second quarter of the vmalloc +area contains shadow memory for the first quarter, the third one holds the +origins. A small part of the fourth quarter contains shadow and origins for the +kernel modules. Please refer to ``arch/x86/include/asm/pgtable_64_types.h`` for +more details. + +When an array of pages is mapped into a contiguous virtual memory space, their +shadow and origin pages are similarly mapped into contiguous regions. + +References +========== + +E. Stepanov, K. Serebryany. `MemorySanitizer: fast detector of uninitialized +memory use in C++ +`_. +In Proceedings of CGO 2015. + +.. _MemorySanitizer tool: https://clang.llvm.org/docs/MemorySanitizer.html +.. _LLVM documentation: https://llvm.org/docs/GettingStarted.html +.. _LKML discussion: https://lore.kernel.org/all/20220614144853.3693273-1-glider@google.com/ -- cgit v1.2.3 From def76fd549c513bb90278a8d6d0fe3ef3faa20a7 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Fri, 16 Sep 2022 15:22:56 +0800 Subject: mm/page_alloc: remove obsolete gfpflags_normal_context() Since commit dacb5d8875cc ("tcp: fix page frag corruption on page fault"), there's no caller of gfpflags_normal_context(). Remove it as this helper is strictly tied to the sk page frag usage and there won't be other user in the future. [linmiaohe@huawei.com: fix htmldocs] Link: https://lkml.kernel.org/r/1bc55727-9b66-0e9e-c306-f10c4716ea89@huawei.com Link: https://lkml.kernel.org/r/20220916072257.9639-16-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: David Hildenbrand Reviewed-by: Anshuman Khandual Reviewed-by: Oscar Salvador Cc: Matthew Wilcox Signed-off-by: Andrew Morton --- Documentation/core-api/mm-api.rst | 3 --- include/linux/gfp.h | 23 ----------------------- 2 files changed, 26 deletions(-) (limited to 'Documentation') diff --git a/Documentation/core-api/mm-api.rst b/Documentation/core-api/mm-api.rst index 1ebcc6c3fafe..f5dde5bceaea 100644 --- a/Documentation/core-api/mm-api.rst +++ b/Documentation/core-api/mm-api.rst @@ -19,9 +19,6 @@ User Space Memory Access Memory Allocation Controls ========================== -.. kernel-doc:: include/linux/gfp.h - :internal: - .. kernel-doc:: include/linux/gfp_types.h :doc: Page mobility and placement hints diff --git a/include/linux/gfp.h b/include/linux/gfp.h index ea6cb9399152..ef4aea3b356e 100644 --- a/include/linux/gfp.h +++ b/include/linux/gfp.h @@ -36,29 +36,6 @@ static inline bool gfpflags_allow_blocking(const gfp_t gfp_flags) return !!(gfp_flags & __GFP_DIRECT_RECLAIM); } -/** - * gfpflags_normal_context - is gfp_flags a normal sleepable context? - * @gfp_flags: gfp_flags to test - * - * Test whether @gfp_flags indicates that the allocation is from the - * %current context and allowed to sleep. - * - * An allocation being allowed to block doesn't mean it owns the %current - * context. When direct reclaim path tries to allocate memory, the - * allocation context is nested inside whatever %current was doing at the - * time of the original allocation. The nested allocation may be allowed - * to block but modifying anything %current owns can corrupt the outer - * context's expectations. - * - * %true result from this function indicates that the allocation context - * can sleep and use anything that's associated with %current. - */ -static inline bool gfpflags_normal_context(const gfp_t gfp_flags) -{ - return (gfp_flags & (__GFP_DIRECT_RECLAIM | __GFP_MEMALLOC)) == - __GFP_DIRECT_RECLAIM; -} - #ifdef CONFIG_HIGHMEM #define OPT_ZONE_HIGHMEM ZONE_HIGHMEM #else -- cgit v1.2.3 From 58ac9a8993a13ebcbb0682ede0e3a158b4a41b28 Mon Sep 17 00:00:00 2001 From: Zach O'Keefe Date: Thu, 22 Sep 2022 15:40:38 -0700 Subject: mm/khugepaged: attempt to map file/shmem-backed pte-mapped THPs by pmds The main benefit of THPs are that they can be mapped at the pmd level, increasing the likelihood of TLB hit and spending less cycles in page table walks. pte-mapped hugepages - that is - hugepage-aligned compound pages of order HPAGE_PMD_ORDER mapped by ptes - although being contiguous in physical memory, don't have this advantage. In fact, one could argue they are detrimental to system performance overall since they occupy a precious hugepage-aligned/sized region of physical memory that could otherwise be used more effectively. Additionally, pte-mapped hugepages can be the cheapest memory to collapse for khugepaged since no new hugepage allocation or copying of memory contents is necessary - we only need to update the mapping page tables. In the anonymous collapse path, we are able to collapse pte-mapped hugepages (albeit, perhaps suboptimally), but the file/shmem path makes no effort when compound pages (of any order) are encountered. Identify pte-mapped hugepages in the file/shmem collapse path. The final step of which makes a racy check of the value of the pmd to ensure it maps a pte table. This should be fine, since races that result in false-positive (i.e. attempt collapse even though we shouldn't) will fail later in collapse_pte_mapped_thp() once we actually lock mmap_lock and reinspect the pmd value. Races that result in false-negatives (i.e. where we decide to not attempt collapse, but should have) shouldn't be an issue, since in the worst case, we do nothing - which is what we've done up to this point. We make a similar check in retract_page_tables(). If we do think we've found a pte-mapped hugepgae in khugepaged context, attempt to update page tables mapping this hugepage. Note that these collapses still count towards the /sys/kernel/mm/transparent_hugepage/khugepaged/pages_collapsed counter, and if the pte-mapped hugepage was also mapped into multiple process' address spaces, could be incremented for each page table update. Since we increment the counter when a pte-mapped hugepage is successfully added to the list of to-collapse pte-mapped THPs, it's possible that we never actually update the page table either. This is different from how file/shmem pages_collapsed accounting works today where only a successful page cache update is counted (it's also possible here that no page tables are actually changed). Though it incurs some slop, this is preferred to either not accounting for the event at all, or plumbing through data in struct mm_slot on whether to account for the collapse or not. Also note that work still needs to be done to support arbitrary compound pages, and that this should all be converted to using folios. [shy828301@gmail.com: Spelling mistake, update comment, and add Documentation] Link: https://lore.kernel.org/linux-mm/CAHbLzkpHwZxFzjfX9nxVoRhzup8WMjMfyL6Xiq8mZ9M-N3ombw@mail.gmail.com/ Link: https://lkml.kernel.org/r/20220907144521.3115321-3-zokeefe@google.com Link: https://lkml.kernel.org/r/20220922224046.1143204-3-zokeefe@google.com Signed-off-by: Zach O'Keefe Reviewed-by: Yang Shi Cc: Axel Rasmussen Cc: Chris Kennelly Cc: David Hildenbrand Cc: David Rientjes Cc: Hugh Dickins Cc: James Houghton Cc: "Kirill A. Shutemov" Cc: Matthew Wilcox Cc: Miaohe Lin Cc: Minchan Kim Cc: Pasha Tatashin Cc: Peter Xu Cc: Rongwei Wang Cc: SeongJae Park Cc: Song Liu Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- Documentation/admin-guide/mm/transhuge.rst | 9 +++- include/trace/events/huge_memory.h | 1 + mm/khugepaged.c | 69 +++++++++++++++++++++++++++--- 3 files changed, 71 insertions(+), 8 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst index 8e3418ec4503..8ee78ec232eb 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -191,7 +191,14 @@ allocation failure to throttle the next allocation attempt:: /sys/kernel/mm/transparent_hugepage/khugepaged/alloc_sleep_millisecs -The khugepaged progress can be seen in the number of pages collapsed:: +The khugepaged progress can be seen in the number of pages collapsed (note +that this counter may not be an exact count of the number of pages +collapsed, since "collapsed" could mean multiple things: (1) A PTE mapping +being replaced by a PMD mapping, or (2) All 4K physical pages replaced by +one 2M hugepage. Each may happen independently, or together, depending on +the type of memory and the failures that occur. As such, this value should +be interpreted roughly as a sign of progress, and counters in /proc/vmstat +consulted for more accurate accounting):: /sys/kernel/mm/transparent_hugepage/khugepaged/pages_collapsed diff --git a/include/trace/events/huge_memory.h b/include/trace/events/huge_memory.h index 55392bf30a03..fbbb25494d60 100644 --- a/include/trace/events/huge_memory.h +++ b/include/trace/events/huge_memory.h @@ -17,6 +17,7 @@ EM( SCAN_EXCEED_SHARED_PTE, "exceed_shared_pte") \ EM( SCAN_PTE_NON_PRESENT, "pte_non_present") \ EM( SCAN_PTE_UFFD_WP, "pte_uffd_wp") \ + EM( SCAN_PTE_MAPPED_HUGEPAGE, "pte_mapped_hugepage") \ EM( SCAN_PAGE_RO, "no_writable_page") \ EM( SCAN_LACK_REFERENCED_PAGE, "lack_referenced_page") \ EM( SCAN_PAGE_NULL, "page_null") \ diff --git a/mm/khugepaged.c b/mm/khugepaged.c index b3ebe90a66d9..b1e3f83c4eb2 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -35,6 +35,7 @@ enum scan_result { SCAN_EXCEED_SHARED_PTE, SCAN_PTE_NON_PRESENT, SCAN_PTE_UFFD_WP, + SCAN_PTE_MAPPED_HUGEPAGE, SCAN_PAGE_RO, SCAN_LACK_REFERENCED_PAGE, SCAN_PAGE_NULL, @@ -1320,20 +1321,24 @@ static void collect_mm_slot(struct khugepaged_mm_slot *mm_slot) * Notify khugepaged that given addr of the mm is pte-mapped THP. Then * khugepaged should try to collapse the page table. */ -static void khugepaged_add_pte_mapped_thp(struct mm_struct *mm, +static bool khugepaged_add_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) { struct khugepaged_mm_slot *mm_slot; struct mm_slot *slot; + bool ret = false; VM_BUG_ON(addr & ~HPAGE_PMD_MASK); spin_lock(&khugepaged_mm_lock); slot = mm_slot_lookup(mm_slots_hash, mm); mm_slot = mm_slot_entry(slot, struct khugepaged_mm_slot, slot); - if (likely(mm_slot && mm_slot->nr_pte_mapped_thp < MAX_PTE_MAPPED_THP)) + if (likely(mm_slot && mm_slot->nr_pte_mapped_thp < MAX_PTE_MAPPED_THP)) { mm_slot->pte_mapped_thp[mm_slot->nr_pte_mapped_thp++] = addr; + ret = true; + } spin_unlock(&khugepaged_mm_lock); + return ret; } static void collapse_and_free_pmd(struct mm_struct *mm, struct vm_area_struct *vma, @@ -1370,9 +1375,16 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) pte_t *start_pte, *pte; pmd_t *pmd; spinlock_t *ptl; - int count = 0; + int count = 0, result = SCAN_FAIL; int i; + mmap_assert_write_locked(mm); + + /* Fast check before locking page if not PMD mapping PTE table */ + result = find_pmd_or_thp_or_none(mm, haddr, &pmd); + if (result != SCAN_SUCCEED) + return; + if (!vma || !vma->vm_file || !range_in_vma(vma, haddr, haddr + HPAGE_PMD_SIZE)) return; @@ -1726,9 +1738,16 @@ static int collapse_file(struct mm_struct *mm, struct file *file, /* * If file was truncated then extended, or hole-punched, before * we locked the first page, then a THP might be there already. + * This will be discovered on the first iteration. */ if (PageTransCompound(page)) { - result = SCAN_PAGE_COMPOUND; + struct page *head = compound_head(page); + + result = compound_order(head) == HPAGE_PMD_ORDER && + head->index == start + /* Maybe PMD-mapped */ + ? SCAN_PTE_MAPPED_HUGEPAGE + : SCAN_PAGE_COMPOUND; goto out_unlock; } @@ -1962,11 +1981,23 @@ static int khugepaged_scan_file(struct mm_struct *mm, struct file *file, } /* - * XXX: khugepaged should compact smaller compound pages + * TODO: khugepaged should compact smaller compound pages * into a PMD sized page */ if (PageTransCompound(page)) { - result = SCAN_PAGE_COMPOUND; + struct page *head = compound_head(page); + + result = compound_order(head) == HPAGE_PMD_ORDER && + head->index == start + /* Maybe PMD-mapped */ + ? SCAN_PTE_MAPPED_HUGEPAGE + : SCAN_PAGE_COMPOUND; + /* + * For SCAN_PTE_MAPPED_HUGEPAGE, further processing + * by the caller won't touch the page cache, and so + * it's safe to skip LRU and refcount checks before + * returning. + */ break; } @@ -2026,6 +2057,12 @@ static int khugepaged_scan_file(struct mm_struct *mm, struct file *file, static void khugepaged_collapse_pte_mapped_thps(struct khugepaged_mm_slot *mm_slot) { } + +static bool khugepaged_add_pte_mapped_thp(struct mm_struct *mm, + unsigned long addr) +{ + return false; +} #endif static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result, @@ -2118,8 +2155,26 @@ skip: &mmap_locked, cc); } - if (*result == SCAN_SUCCEED) + switch (*result) { + case SCAN_PTE_MAPPED_HUGEPAGE: { + pmd_t *pmd; + + *result = find_pmd_or_thp_or_none(mm, + khugepaged_scan.address, + &pmd); + if (*result != SCAN_SUCCEED) + break; + if (!khugepaged_add_pte_mapped_thp(mm, + khugepaged_scan.address)) + break; + } fallthrough; + case SCAN_SUCCEED: ++khugepaged_pages_collapsed; + break; + default: + break; + } + /* move to next address */ khugepaged_scan.address += HPAGE_PMD_SIZE; progress += HPAGE_PMD_NR; -- cgit v1.2.3 From b25806dcd3d5248833f7d2544ee29a701735159f Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Mon, 26 Sep 2022 09:57:02 -0400 Subject: mm: memcontrol: deprecate swapaccounting=0 mode The swapaccounting= commandline option already does very little today. To close a trivial containment failure case, the swap ownership tracking part of the swap controller has recently become mandatory (see commit 2d1c498072de ("mm: memcontrol: make swap tracking an integral part of memory control") for details), which makes up the majority of the work during swapout, swapin, and the swap slot map. The only thing left under this flag is the page_counter operations and the visibility of the swap control files in the first place, which are rather meager savings. There also aren't many scenarios, if any, where controlling the memory of a cgroup while allowing it unlimited access to a global swap space is a workable resource isolation strategy. On the other hand, there have been several bugs and confusion around the many possible swap controller states (cgroup1 vs cgroup2 behavior, memory accounting without swap accounting, memcg runtime disabled). This puts the maintenance overhead of retaining the toggle above its practical benefits. Deprecate it. Link: https://lkml.kernel.org/r/20220926135704.400818-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Suggested-by: Shakeel Butt Reviewed-by: Shakeel Butt Cc: Hugh Dickins Cc: Michal Hocko Cc: Roman Gushchin Signed-off-by: Andrew Morton --- Documentation/admin-guide/kernel-parameters.txt | 6 --- mm/memcontrol.c | 50 +++++-------------------- 2 files changed, 10 insertions(+), 46 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 3b95f65bafe2..99a13f2be2ef 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -6036,12 +6036,6 @@ This parameter controls use of the Protected Execution Facility on pSeries. - swapaccount= [KNL] - Format: [0|1] - Enable accounting of swap in memory resource - controller if no parameter or 1 is given or disable - it if 0 is given (See Documentation/admin-guide/cgroup-v1/memory.rst) - swiotlb= [ARM,IA-64,PPC,MIPS,X86] Format: { [,] | force | noforce } -- Number of I/O TLB slabs diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9e3c010ca676..4be1b48b9659 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -88,22 +88,6 @@ static bool cgroup_memory_nosocket __ro_after_init; /* Kernel memory accounting disabled? */ static bool cgroup_memory_nokmem __ro_after_init; -/* Whether the swap controller is active */ -#ifdef CONFIG_MEMCG_SWAP -static bool cgroup_memory_noswap __initdata; - -static DEFINE_STATIC_KEY_FALSE(memcg_swap_enabled_key); -static inline bool memcg_swap_enabled(void) -{ - return static_branch_likely(&memcg_swap_enabled_key); -} -#else -static inline bool memcg_swap_enabled(void) -{ - return false; -} -#endif - #ifdef CONFIG_CGROUP_WRITEBACK static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq); #endif @@ -111,7 +95,7 @@ static DECLARE_WAIT_QUEUE_HEAD(memcg_cgwb_frn_waitq); /* Whether legacy memory+swap accounting is active */ static bool do_memsw_account(void) { - return !cgroup_subsys_on_dfl(memory_cgrp_subsys) && memcg_swap_enabled(); + return !cgroup_subsys_on_dfl(memory_cgrp_subsys); } #define THRESHOLDS_EVENTS_TARGET 128 @@ -7379,7 +7363,7 @@ void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry) if (!mem_cgroup_is_root(memcg)) page_counter_uncharge(&memcg->memory, nr_entries); - if (memcg_swap_enabled() && memcg != swap_memcg) { + if (memcg != swap_memcg) { if (!mem_cgroup_is_root(swap_memcg)) page_counter_charge(&swap_memcg->memsw, nr_entries); page_counter_uncharge(&memcg->memsw, nr_entries); @@ -7431,7 +7415,7 @@ int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry) memcg = mem_cgroup_id_get_online(memcg); - if (memcg_swap_enabled() && !mem_cgroup_is_root(memcg) && + if (!mem_cgroup_is_root(memcg) && !page_counter_try_charge(&memcg->swap, nr_pages, &counter)) { memcg_memory_event(memcg, MEMCG_SWAP_MAX); memcg_memory_event(memcg, MEMCG_SWAP_FAIL); @@ -7466,7 +7450,7 @@ void __mem_cgroup_uncharge_swap(swp_entry_t entry, unsigned int nr_pages) rcu_read_lock(); memcg = mem_cgroup_from_id(id); if (memcg) { - if (memcg_swap_enabled() && !mem_cgroup_is_root(memcg)) { + if (!mem_cgroup_is_root(memcg)) { if (cgroup_subsys_on_dfl(memory_cgrp_subsys)) page_counter_uncharge(&memcg->swap, nr_pages); else @@ -7482,7 +7466,7 @@ long mem_cgroup_get_nr_swap_pages(struct mem_cgroup *memcg) { long nr_swap_pages = get_nr_swap_pages(); - if (!memcg_swap_enabled() || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + if (mem_cgroup_disabled() || do_memsw_account()) return nr_swap_pages; for (; memcg != root_mem_cgroup; memcg = parent_mem_cgroup(memcg)) nr_swap_pages = min_t(long, nr_swap_pages, @@ -7499,7 +7483,7 @@ bool mem_cgroup_swap_full(struct folio *folio) if (vm_swap_full()) return true; - if (!memcg_swap_enabled() || !cgroup_subsys_on_dfl(memory_cgrp_subsys)) + if (do_memsw_account()) return false; memcg = folio_memcg(folio); @@ -7519,10 +7503,9 @@ bool mem_cgroup_swap_full(struct folio *folio) static int __init setup_swap_account(char *s) { - bool res; - - if (!kstrtobool(s, &res)) - cgroup_memory_noswap = !res; + pr_warn_once("The swapaccount= commandline option is deprecated. " + "Please report your usecase to linux-mm@kvack.org if you " + "depend on this functionality.\n"); return 1; } __setup("swapaccount=", setup_swap_account); @@ -7791,24 +7774,11 @@ static struct cftype zswap_files[] = { }; #endif /* CONFIG_MEMCG_KMEM && CONFIG_ZSWAP */ -/* - * If mem_cgroup_swap_init() is implemented as a subsys_initcall() - * instead of a core_initcall(), this could mean cgroup_memory_noswap still - * remains set to false even when memcg is disabled via "cgroup_disable=memory" - * boot parameter. This may result in premature OOPS inside - * mem_cgroup_get_nr_swap_pages() function in corner cases. - */ static int __init mem_cgroup_swap_init(void) { - /* No memory control -> no swap control */ if (mem_cgroup_disabled()) - cgroup_memory_noswap = true; - - if (cgroup_memory_noswap) return 0; - static_branch_enable(&memcg_swap_enabled_key); - WARN_ON(cgroup_add_dfl_cftypes(&memory_cgrp_subsys, swap_files)); WARN_ON(cgroup_add_legacy_cftypes(&memory_cgrp_subsys, memsw_files)); #if defined(CONFIG_MEMCG_KMEM) && defined(CONFIG_ZSWAP) @@ -7816,6 +7786,6 @@ static int __init mem_cgroup_swap_init(void) #endif return 0; } -core_initcall(mem_cgroup_swap_init); +subsys_initcall(mem_cgroup_swap_init); #endif /* CONFIG_MEMCG_SWAP */ -- cgit v1.2.3 From e55b9f96860f6c6026cff97966a740576285e07b Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Mon, 26 Sep 2022 09:57:04 -0400 Subject: mm: memcontrol: drop dead CONFIG_MEMCG_SWAP config symbol Since 2d1c498072de ("mm: memcontrol: make swap tracking an integral part of memory control"), CONFIG_MEMCG_SWAP hasn't been a user-visible config option anymore, it just means CONFIG_MEMCG && CONFIG_SWAP. Update the sites accordingly and drop the symbol. [ While touching the docs, remove two references to CONFIG_MEMCG_KMEM, which hasn't been a user-visible symbol for over half a decade. ] Link: https://lkml.kernel.org/r/20220926135704.400818-5-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Acked-by: Shakeel Butt Cc: Hugh Dickins Cc: Michal Hocko Cc: Roman Gushchin Signed-off-by: Andrew Morton --- Documentation/admin-guide/cgroup-v1/memory.rst | 4 +--- arch/mips/configs/db1xxx_defconfig | 1 - arch/mips/configs/generic_defconfig | 1 - arch/powerpc/configs/powernv_defconfig | 1 - arch/powerpc/configs/pseries_defconfig | 1 - arch/sh/configs/sdk7786_defconfig | 1 - arch/sh/configs/urquell_defconfig | 1 - include/linux/swap.h | 2 +- include/linux/swap_cgroup.h | 4 ++-- init/Kconfig | 5 ----- mm/Makefile | 4 +++- mm/memcontrol.c | 6 +++--- tools/testing/selftests/cgroup/config | 1 - 13 files changed, 10 insertions(+), 22 deletions(-) (limited to 'Documentation') diff --git a/Documentation/admin-guide/cgroup-v1/memory.rst b/Documentation/admin-guide/cgroup-v1/memory.rst index 2cc502a75ef6..5b86245450bd 100644 --- a/Documentation/admin-guide/cgroup-v1/memory.rst +++ b/Documentation/admin-guide/cgroup-v1/memory.rst @@ -299,7 +299,7 @@ Per-node-per-memcgroup LRU (cgroup's private LRU) is guarded by lruvec->lru_lock; PG_lru bit of page->flags is cleared before isolating a page from its LRU under lruvec->lru_lock. -2.7 Kernel Memory Extension (CONFIG_MEMCG_KMEM) +2.7 Kernel Memory Extension ----------------------------------------------- With the Kernel memory extension, the Memory Controller is able to limit @@ -386,8 +386,6 @@ U != 0, K >= U: a. Enable CONFIG_CGROUPS b. Enable CONFIG_MEMCG -c. Enable CONFIG_MEMCG_SWAP (to use swap extension) -d. Enable CONFIG_MEMCG_KMEM (to use kmem extension) 3.1. Prepare the cgroups (see cgroups.txt, Why are cgroups needed?) ------------------------------------------------------------------- diff --git a/arch/mips/configs/db1xxx_defconfig b/arch/mips/configs/db1xxx_defconfig index b8bd66300996..83cbdecb27e6 100644 --- a/arch/mips/configs/db1xxx_defconfig +++ b/arch/mips/configs/db1xxx_defconfig @@ -9,7 +9,6 @@ CONFIG_HIGH_RES_TIMERS=y CONFIG_LOG_BUF_SHIFT=16 CONFIG_CGROUPS=y CONFIG_MEMCG=y -CONFIG_MEMCG_SWAP=y CONFIG_BLK_CGROUP=y CONFIG_CGROUP_SCHED=y CONFIG_CFS_BANDWIDTH=y diff --git a/arch/mips/configs/generic_defconfig b/arch/mips/configs/generic_defconfig index 714169e411cf..48e4e251779b 100644 --- a/arch/mips/configs/generic_defconfig +++ b/arch/mips/configs/generic_defconfig @@ -3,7 +3,6 @@ CONFIG_NO_HZ_IDLE=y CONFIG_IKCONFIG=y CONFIG_IKCONFIG_PROC=y CONFIG_MEMCG=y -CONFIG_MEMCG_SWAP=y CONFIG_BLK_CGROUP=y CONFIG_CFS_BANDWIDTH=y CONFIG_RT_GROUP_SCHED=y diff --git a/arch/powerpc/configs/powernv_defconfig b/arch/powerpc/configs/powernv_defconfig index 49f49c263935..4acca5263404 100644 --- a/arch/powerpc/configs/powernv_defconfig +++ b/arch/powerpc/configs/powernv_defconfig @@ -17,7 +17,6 @@ CONFIG_LOG_CPU_MAX_BUF_SHIFT=13 CONFIG_NUMA_BALANCING=y CONFIG_CGROUPS=y CONFIG_MEMCG=y -CONFIG_MEMCG_SWAP=y CONFIG_CGROUP_SCHED=y CONFIG_CGROUP_FREEZER=y CONFIG_CPUSETS=y diff --git a/arch/powerpc/configs/pseries_defconfig b/arch/powerpc/configs/pseries_defconfig index b571d084c148..fead14ebb1fc 100644 --- a/arch/powerpc/configs/pseries_defconfig +++ b/arch/powerpc/configs/pseries_defconfig @@ -16,7 +16,6 @@ CONFIG_LOG_CPU_MAX_BUF_SHIFT=13 CONFIG_NUMA_BALANCING=y CONFIG_CGROUPS=y CONFIG_MEMCG=y -CONFIG_MEMCG_SWAP=y CONFIG_CGROUP_SCHED=y CONFIG_CGROUP_FREEZER=y CONFIG_CPUSETS=y diff --git a/arch/sh/configs/sdk7786_defconfig b/arch/sh/configs/sdk7786_defconfig index a8662b6927ec..97b7356639ed 100644 --- a/arch/sh/configs/sdk7786_defconfig +++ b/arch/sh/configs/sdk7786_defconfig @@ -16,7 +16,6 @@ CONFIG_CPUSETS=y # CONFIG_PROC_PID_CPUSET is not set CONFIG_CGROUP_CPUACCT=y CONFIG_CGROUP_MEMCG=y -CONFIG_CGROUP_MEMCG_SWAP=y CONFIG_CGROUP_SCHED=y CONFIG_RT_GROUP_SCHED=y CONFIG_BLK_CGROUP=y diff --git a/arch/sh/configs/urquell_defconfig b/arch/sh/configs/urquell_defconfig index cb2f56468fe0..be478f3148f2 100644 --- a/arch/sh/configs/urquell_defconfig +++ b/arch/sh/configs/urquell_defconfig @@ -14,7 +14,6 @@ CONFIG_CPUSETS=y # CONFIG_PROC_PID_CPUSET is not set CONFIG_CGROUP_CPUACCT=y CONFIG_CGROUP_MEMCG=y -CONFIG_CGROUP_MEMCG_SWAP=y CONFIG_CGROUP_SCHED=y CONFIG_RT_GROUP_SCHED=y CONFIG_BLK_DEV_INITRD=y diff --git a/include/linux/swap.h b/include/linux/swap.h index fc8d98660326..a18cf4b7c724 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -666,7 +666,7 @@ static inline void folio_throttle_swaprate(struct folio *folio, gfp_t gfp) cgroup_throttle_swaprate(&folio->page, gfp); } -#ifdef CONFIG_MEMCG_SWAP +#if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP) void mem_cgroup_swapout(struct folio *folio, swp_entry_t entry); int __mem_cgroup_try_charge_swap(struct folio *folio, swp_entry_t entry); static inline int mem_cgroup_try_charge_swap(struct folio *folio, diff --git a/include/linux/swap_cgroup.h b/include/linux/swap_cgroup.h index a12dd1c3966c..ae73a87775b3 100644 --- a/include/linux/swap_cgroup.h +++ b/include/linux/swap_cgroup.h @@ -4,7 +4,7 @@ #include -#ifdef CONFIG_MEMCG_SWAP +#if defined(CONFIG_MEMCG) && defined(CONFIG_SWAP) extern unsigned short swap_cgroup_cmpxchg(swp_entry_t ent, unsigned short old, unsigned short new); @@ -40,6 +40,6 @@ static inline void swap_cgroup_swapoff(int type) return; } -#endif /* CONFIG_MEMCG_SWAP */ +#endif #endif /* __LINUX_SWAP_CGROUP_H */ diff --git a/init/Kconfig b/init/Kconfig index 532362fcfe31..7d86cf6b3012 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -958,11 +958,6 @@ config MEMCG help Provides control over the memory footprint of tasks in a cgroup. -config MEMCG_SWAP - bool - depends on MEMCG && SWAP - default y - config MEMCG_KMEM bool depends on MEMCG && !SLOB diff --git a/mm/Makefile b/mm/Makefile index cc23b0052584..8e105e5b3e29 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -98,7 +98,9 @@ obj-$(CONFIG_DEVICE_MIGRATION) += migrate_device.o obj-$(CONFIG_TRANSPARENT_HUGEPAGE) += huge_memory.o khugepaged.o obj-$(CONFIG_PAGE_COUNTER) += page_counter.o obj-$(CONFIG_MEMCG) += memcontrol.o vmpressure.o -obj-$(CONFIG_MEMCG_SWAP) += swap_cgroup.o +ifdef CONFIG_SWAP +obj-$(CONFIG_MEMCG) += swap_cgroup.o +endif obj-$(CONFIG_CGROUP_HUGETLB) += hugetlb_cgroup.o obj-$(CONFIG_GUP_TEST) += gup_test.o obj-$(CONFIG_MEMORY_FAILURE) += memory-failure.o diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 76bb0a18a2f3..61e05fc281fb 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3423,7 +3423,7 @@ void split_page_memcg(struct page *head, unsigned int nr) css_get_many(&memcg->css, nr - 1); } -#ifdef CONFIG_MEMCG_SWAP +#ifdef CONFIG_SWAP /** * mem_cgroup_move_swap_account - move swap charge and swap_cgroup's record. * @entry: swap entry to be moved @@ -7296,7 +7296,7 @@ static int __init mem_cgroup_init(void) } subsys_initcall(mem_cgroup_init); -#ifdef CONFIG_MEMCG_SWAP +#ifdef CONFIG_SWAP static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg) { while (!refcount_inc_not_zero(&memcg->id.ref)) { @@ -7788,4 +7788,4 @@ static int __init mem_cgroup_swap_init(void) } subsys_initcall(mem_cgroup_swap_init); -#endif /* CONFIG_MEMCG_SWAP */ +#endif /* CONFIG_SWAP */ diff --git a/tools/testing/selftests/cgroup/config b/tools/testing/selftests/cgroup/config index 84fe884fad86..97d549ee894f 100644 --- a/tools/testing/selftests/cgroup/config +++ b/tools/testing/selftests/cgroup/config @@ -4,5 +4,4 @@ CONFIG_CGROUP_FREEZER=y CONFIG_CGROUP_SCHED=y CONFIG_MEMCG=y CONFIG_MEMCG_KMEM=y -CONFIG_MEMCG_SWAP=y CONFIG_PAGE_COUNTER=y -- cgit v1.2.3