kernel/linux.git/mm/cma.c, branch v6.19.12

mm/cma: refuse handing out non-contiguous page ranges

2025-09-21T21:22:06+00:00

Let's disallow handing out PFN ranges with non-contiguous pages, so we can remove the nth-page usage in __cma_alloc(), and so any callers don't have to worry about that either when wanting to blindly iterate pages. This is really only a problem in configs with SPARSEMEM but without SPARSEMEM_VMEMMAP, and only when we would cross memory sections in some cases. Will this cause harm? Probably not, because it's mostly 32bit that does not support SPARSEMEM_VMEMMAP. If this ever becomes a problem we could look into allocating the memmap for the memory sections spanned by a single CMA region in one go from memblock. [david@redhat.com: we can have NUMMU configs with SPARSEMEM enabled] Link: https://lkml.kernel.org/r/6ec933b1-b3f7-41c0-95d8-e518bb87375e@redhat.com Link: https://lkml.kernel.org/r/20250901150359.867252-23-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Alexandru Elisei Reviewed-by: Lorenzo Stoakes Signed-off-by: Andrew Morton

mm/cma: add 'available count' and 'total count' to trace_cma_alloc_start

2025-09-13T23:55:15+00:00

This makes cma info more intuitive during debugging. Show up in the trace as: 279.814717: cma_alloc_start: name=reserved request_count=4 available_count=8096 total_count=8192 align=0 309.790580: cma_alloc_start: name=reserved request_count=4 available_count=8092 total_count=8192 align=0 317.046609: cma_alloc_start: name=reserved request_count=4 available_count=8088 total_count=8192 align=0 Link: https://lkml.kernel.org/r/8a79284879c529f467478552825154b018076e95.1755729178.git.gaoxiang17@xiaomi.com Signed-off-by: gaoxiang17 Cc: David Hildenbrand Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Suren Baghdasaryan Cc: Vlastimil Babka Signed-off-by: Andrew Morton

mm: cma: simplify cma_debug_show_areas()

2025-07-25T02:12:36+00:00

The function opencodes for_each_clear_bitrange(). Fix that and drop most of housekeeping code. Link: https://lkml.kernel.org/r/20250719205401.399475-2-yury.norov@gmail.com Signed-off-by: Yury Norov (NVIDIA) Acked-by: David Hildenbrand Signed-off-by: Andrew Morton

cma: move memory allocation to a helper function

2025-07-13T23:38:24+00:00

__cma_declare_contiguous_nid() tries to allocate memory in several ways: * on systems with 64 bit physical address and enough memory it first attempts to allocate memory just above 4GiB * if that fails, on systems with HIGHMEM the next attempt is from high memory * and at last, if none of the previous attempts succeeded, or was even tried because of incompatible configuration, the memory is allocated anywhere within specified limits. Move all the allocation logic to a helper function to make these steps more obvious. Link: https://lkml.kernel.org/r/20250703184711.3485940-4-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: David Hildenbrand Acked-by: Oscar Salvador Cc: Alexandre Ghiti Cc: Pratyush Yadav Signed-off-by: Andrew Morton

cma: split reservation of fixed area into a helper function

2025-07-13T23:38:24+00:00

Move the check that verifies that reservation of fixed area does not cross HIGHMEM boundary and the actual memblock_resrve() call into a helper function. This makes code more readable and decouples logic related to CONFIG_HIGHMEM from the core functionality of __cma_declare_contiguous_nid(). Link: https://lkml.kernel.org/r/20250703184711.3485940-3-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Oscar Salvador Acked-by: David Hildenbrand Cc: Alexandre Ghiti Cc: Pratyush Yadav Signed-off-by: Andrew Morton

cma: move __cma_declare_contiguous_nid() before its usage

2025-07-13T23:38:24+00:00

Patch series "cma: factor out allocation logic from __cma_declare_contiguous_nid", v2. We've discussed earlier that HIGHMEM related logic is spread all over __cma_declare_contiguous_nid(). These patches decouple it into helper functions. This patch (of 3): Move __cma_declare_contiguous_nid() before its usage and kill forward declaration. Link: https://lkml.kernel.org/r/20250703184711.3485940-1-rppt@kernel.org Link: https://lkml.kernel.org/r/20250703184711.3485940-2-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Acked-by: Oscar Salvador Acked-by: David Hildenbrand Cc: Alexandre Ghiti Cc: Pratyush Yadav Signed-off-by: Andrew Morton

mm/cma: use str_plural() in cma_declare_contiguous_multi()

2025-07-13T23:38:23+00:00

Use the string choice helper function str_plural() to simplify the code and to fix the following Coccinelle/coccicheck warning reported by string_choices.cocci: opportunity for str_plural(nr) Link: https://lkml.kernel.org/r/20250630132318.41339-2-thorsten.blum@linux.dev Signed-off-by: Thorsten Blum Reviewed-by: Dev Jain Tested-by: Dev Jain Reviewed-by: Anshuman Khandual Acked-by: David Hildenbrand Signed-off-by: Andrew Morton

mm/page_isolation: remove migratetype parameter from more functions

2025-07-13T23:38:18+00:00

migratetype is no longer overwritten during pageblock isolation, start_isolate_page_range(), has_unmovable_pages(), and set_migratetype_isolate() no longer need which migratetype to restore during isolation failure. For has_unmoable_pages(), it needs to know if the isolation is for CMA allocation, so adding PB_ISOLATE_MODE_CMA_ALLOC provide the information. At the same time change isolation flags to enum pb_isolate_mode (PB_ISOLATE_MODE_MEM_OFFLINE, PB_ISOLATE_MODE_CMA_ALLOC, PB_ISOLATE_MODE_OTHER). Remove REPORT_FAILURE and check PB_ISOLATE_MODE_MEM_OFFLINE, since only PB_ISOLATE_MODE_MEM_OFFLINE reports isolation failures. alloc_contig_range() no longer needs migratetype. Replace it with a newly defined acr_flags_t to tell if an allocation is for CMA. So does __alloc_contig_migrate_range(). Add ACR_FLAGS_NONE (set to 0) to indicate ordinary allocations. Link: https://lkml.kernel.org/r/20250617021115.2331563-7-ziy@nvidia.com Signed-off-by: Zi Yan Reviewed-by: Vlastimil Babka Acked-by: David Hildenbrand Cc: Baolin Wang Cc: Brendan Jackman Cc: Johannes Weiner Cc: Kirill A. Shuemov Cc: Mel Gorman Cc: Michal Hocko Cc: Oscar Salvador Cc: Richard Chang Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton

mm/cma: pair the trace_cma_alloc_start/finish

2025-07-10T05:41:58+00:00

In the bad input validation cases, there is no trace_cma_alloc_finish to match the trace_cma_alloc_start. Move the trace_cma_alloc_start event after the validations. Link: https://lkml.kernel.org/r/20250605072532.972081-1-richardycc@google.com Signed-off-by: Richard Chang Acked-by: David Hildenbrand Cc: Kalesh Singh Cc: Martin Liu Cc: Minchan Kim Signed-off-by: Andrew Morton

Merge tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

2025-05-31T22:44:16+00:00

Pull MM updates from Andrew Morton: - "Add folio_mk_pte()" from Matthew Wilcox simplifies the act of creating a pte which addresses the first page in a folio and reduces the amount of plumbing which architecture must implement to provide this. - "Misc folio patches for 6.16" from Matthew Wilcox is a shower of largely unrelated folio infrastructure changes which clean things up and better prepare us for future work. - "memory,x86,acpi: hotplug memory alignment advisement" from Gregory Price adds early-init code to prevent x86 from leaving physical memory unused when physical address regions are not aligned to memory block size. - "mm/compaction: allow more aggressive proactive compaction" from Michal Clapinski provides some tuning of the (sadly, hard-coded (more sadly, not auto-tuned)) thresholds for our invokation of proactive compaction. In a simple test case, the reduction of a guest VM's memory consumption was dramatic. - "Minor cleanups and improvements to swap freeing code" from Kemeng Shi provides some code cleaups and a small efficiency improvement to this part of our swap handling code. - "ptrace: introduce PTRACE_SET_SYSCALL_INFO API" from Dmitry Levin adds the ability for a ptracer to modify syscalls arguments. At this time we can alter only "system call information that are used by strace system call tampering, namely, syscall number, syscall arguments, and syscall return value. This series should have been incorporated into mm.git's "non-MM" branch, but I goofed. - "fs/proc: extend the PAGEMAP_SCAN ioctl to report guard regions" from Andrei Vagin extends the info returned by the PAGEMAP_SCAN ioctl against /proc/pid/pagemap. This permits CRIU to more efficiently get at the info about guard regions. - "Fix parameter passed to page_mapcount_is_type()" from Gavin Shan implements that fix. No runtime effect is expected because validate_page_before_insert() happens to fix up this error. - "kernel/events/uprobes: uprobe_write_opcode() rewrite" from David Hildenbrand basically brings uprobe text poking into the current decade. Remove a bunch of hand-rolled implementation in favor of using more current facilities. - "mm/ptdump: Drop assumption that pxd_val() is u64" from Anshuman Khandual provides enhancements and generalizations to the pte dumping code. This might be needed when 128-bit Page Table Descriptors are enabled for ARM. - "Always call constructor for kernel page tables" from Kevin Brodsky ensures that the ctor/dtor is always called for kernel pgtables, as it already is for user pgtables. This permits the addition of more functionality such as "insert hooks to protect page tables". This change does result in various architectures performing unnecesary work, but this is fixed up where it is anticipated to occur. - "Rust support for mm_struct, vm_area_struct, and mmap" from Alice Ryhl adds plumbing to permit Rust access to core MM structures. - "fix incorrectly disallowed anonymous VMA merges" from Lorenzo Stoakes takes advantage of some VMA merging opportunities which we've been missing for 15 years. - "mm/madvise: batch tlb flushes for MADV_DONTNEED and MADV_FREE" from SeongJae Park optimizes process_madvise()'s TLB flushing. Instead of flushing each address range in the provided iovec, we batch the flushing across all the iovec entries. The syscall's cost was approximately halved with a microbenchmark which was designed to load this particular operation. - "Track node vacancy to reduce worst case allocation counts" from Sidhartha Kumar makes the maple tree smarter about its node preallocation. stress-ng mmap performance increased by single-digit percentages and the amount of unnecessarily preallocated memory was dramaticelly reduced. - "mm/gup: Minor fix, cleanup and improvements" from Baoquan He removes a few unnecessary things which Baoquan noted when reading the code. - ""Enhance sysfs handling for memory hotplug in weighted interleave" from Rakie Kim "enhances the weighted interleave policy in the memory management subsystem by improving sysfs handling, fixing memory leaks, and introducing dynamic sysfs updates for memory hotplug support". Fixes things on error paths which we are unlikely to hit. - "mm/damon: auto-tune DAMOS for NUMA setups including tiered memory" from SeongJae Park introduces new DAMOS quota goal metrics which eliminate the manual tuning which is required when utilizing DAMON for memory tiering. - "mm/vmalloc.c: code cleanup and improvements" from Baoquan He provides cleanups and small efficiency improvements which Baoquan found via code inspection. - "vmscan: enforce mems_effective during demotion" from Gregory Price changes reclaim to respect cpuset.mems_effective during demotion when possible. because presently, reclaim explicitly ignores cpuset.mems_effective when demoting, which may cause the cpuset settings to violated. This is useful for isolating workloads on a multi-tenant system from certain classes of memory more consistently. - "Clean up split_huge_pmd_locked() and remove unnecessary folio pointers" from Gavin Guo provides minor cleanups and efficiency gains in in the huge page splitting and migrating code. - "Use kmem_cache for memcg alloc" from Huan Yang creates a slab cache for `struct mem_cgroup', yielding improved memory utilization. - "add max arg to swappiness in memory.reclaim and lru_gen" from Zhongkun He adds a new "max" argument to the "swappiness=" argument for memory.reclaim MGLRU's lru_gen. This directs proactive reclaim to reclaim from only anon folios rather than file-backed folios. - "kexec: introduce Kexec HandOver (KHO)" from Mike Rapoport is the first step on the path to permitting the kernel to maintain existing VMs while replacing the host kernel via file-based kexec. At this time only memblock's reserve_mem is preserved. - "mm: Introduce for_each_valid_pfn()" from David Woodhouse provides and uses a smarter way of looping over a pfn range. By skipping ranges of invalid pfns. - "sched/numa: Skip VMA scanning on memory pinned to one NUMA node via cpuset.mems" from Libo Chen removes a lot of pointless VMA scanning when a task is pinned a single NUMA mode. Dramatic performance benefits were seen in some real world cases. - "JFS: Implement migrate_folio for jfs_metapage_aops" from Shivank Garg addresses a warning which occurs during memory compaction when using JFS. - "move all VMA allocation, freeing and duplication logic to mm" from Lorenzo Stoakes moves some VMA code from kernel/fork.c into the more appropriate mm/vma.c. - "mm, swap: clean up swap cache mapping helper" from Kairui Song provides code consolidation and cleanups related to the folio_index() function. - "mm/gup: Cleanup memfd_pin_folios()" from Vishal Moola does that. - "memcg: Fix test_memcg_min/low test failures" from Waiman Long addresses some bogus failures which are being reported by the test_memcontrol selftest. - "eliminate mmap() retry merge, add .mmap_prepare hook" from Lorenzo Stoakes commences the deprecation of file_operations.mmap() in favor of the new file_operations.mmap_prepare(). The latter is more restrictive and prevents drivers from messing with things in ways which, amongst other problems, may defeat VMA merging. - "memcg: decouple memcg and objcg stocks"" from Shakeel Butt decouples the per-cpu memcg charge cache from the objcg's one. This is a step along the way to making memcg and objcg charging NMI-safe, which is a BPF requirement. - "mm/damon: minor fixups and improvements for code, tests, and documents" from SeongJae Park is yet another batch of miscellaneous DAMON changes. Fix and improve minor problems in code, tests and documents. - "memcg: make memcg stats irq safe" from Shakeel Butt converts memcg stats to be irq safe. Another step along the way to making memcg charging and stats updates NMI-safe, a BPF requirement. - "Let unmap_hugepage_range() and several related functions take folio instead of page" from Fan Ni provides folio conversions in the hugetlb code. * tag 'mm-stable-2025-05-31-14-50' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (285 commits) mm: pcp: increase pcp->free_count threshold to trigger free_high mm/hugetlb: convert use of struct page to folio in __unmap_hugepage_range() mm/hugetlb: refactor __unmap_hugepage_range() to take folio instead of page mm/hugetlb: refactor unmap_hugepage_range() to take folio instead of page mm/hugetlb: pass folio instead of page to unmap_ref_private() memcg: objcg stock trylock without irq disabling memcg: no stock lock for cpu hot-unplug memcg: make __mod_memcg_lruvec_state re-entrant safe against irqs memcg: make count_memcg_events re-entrant safe against irqs memcg: make mod_memcg_state re-entrant safe against irqs memcg: move preempt disable to callers of memcg_rstat_updated memcg: memcg_rstat_updated re-entrant safe against irqs mm: khugepaged: decouple SHMEM and file folios' collapse selftests/eventfd: correct test name and improve messages alloc_tag: check mem_profiling_support in alloc_tag_init Docs/damon: update titles and brief introductions to explain DAMOS selftests/damon/_damon_sysfs: read tried regions directories in order mm/damon/tests/core-kunit: add a test for damos_set_filters_default_reject() mm/damon/paddr: remove unused variable, folio_list, in damon_pa_stat() mm/damon/sysfs-schemes: fix wrong comment on damons_sysfs_quota_goal_metric_strs ...