BMC/Intel-BMC/linux.git/mm/nommu.c, branch dev

Merge tag 'module_init-alternate_initcall-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

2015-07-02T17:36:29+00:00

Pull module_init replacement part two from Paul Gortmaker: "Replace module_init with appropriate alternate initcall in non modules. This series converts non-modular code that is using the module_init() call to hook itself into the system to instead use one of our alternate priority initcalls. Unlike the previous series that used device_initcall and hence was a runtime no-op, these commits change to one of the alternate initcalls, because (a) we have them and (b) it seems like the right thing to do. For example, it would seem logical to use arch_initcall for arch specific setup code and fs_initcall for filesystem setup code. This does mean however, that changes in the init ordering will be taking place, and so there is a small risk that some kind of implicit init ordering issue may lie uncovered. But I think it is still better to give these ones sensible priorities than to just assign them all to device_initcall in order to exactly preserve the old ordering. Thad said, we have already made similar changes in core kernel code in commit c96d6660dc65 ("kernel: audit/fix non-modular users of module_init in core code") without any regressions reported, so this type of change isn't without precedent. It has also got the same local testing and linux-next coverage as all the other pull requests that I'm sending for this merge window have got. Once again, there is an unused module_exit function removal that shows up as an outlier upon casual inspection of the diffstat" * tag 'module_init-alternate_initcall-v4.1-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux: x86: perf_event_intel_pt.c: use arch_initcall to hook in enabling x86: perf_event_intel_bts.c: use arch_initcall to hook in enabling mm/page_owner.c: use late_initcall to hook in enabling lib/list_sort: use late_initcall to hook in self tests arm: use subsys_initcall in non-modular pl320 IPC code powerpc: don't use module_init for non-modular core hugetlb code powerpc: use subsys_initcall for Freescale Local Bus x86: don't use module_init for non-modular core bootflag code netfilter: don't use module_init/exit in core IPV4 code fs/notify: don't use module_init for non-modular inotify_user code mm: replace module_init usages with subsys_initcall in nommu.c

mm: nommu: refactor debug and warning prints

2015-06-25T00:49:44+00:00

kenter/kleave/kdebug are wrapper macros to print functions flow and debug information. This set was written before pr_devel() was introduced, so it was controlled by "#if 0" construction. It is questionable if anyone is using them [1] now. This patch removes these macros, converts numerous printk(KERN_WARNING, ...) to use general pr_warn(...) and removes debug print line from validate_mmap_request() function. Signed-off-by: Leon Romanovsky Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: replace module_init usages with subsys_initcall in nommu.c

2015-06-16T18:12:34+00:00

Compiling some arm/m68k configs with "# CONFIG_MMU is not set" reveals two more instances of module_init being used for code that can't possibly be modular, as CONFIG_MMU is either on or off. We replace them with subsys_initcall as per what was done in other mmu-enabled code. Note that direct use of __initcall is discouraged, vs. one of the priority categorized subgroups. As __initcall gets mapped onto device_initcall, our use of subsys_initcall (which makes sense for these files) will thus change this registration from level 6-device to level 4-subsys (i.e. slightly earlier). One might think that core_initcall (l2) or postcore_initcall (l3) would be more appropriate for anything in mm/ but if we look at the actual init functions themselves, we see they are just sysctl setup stuff, and hence the choice of subsys_initcall (l4) seems reasonable. At the same time it minimizes the risk of changing the priority too drastically all at once. We can adjust further in the future. Also, a couple instances of missing ";" at EOL are fixed. Cc: Andrew Morton Cc: linux-mm@kvack.org Signed-off-by: Paul Gortmaker

nommu: use __vfs_read()

2015-04-12T02:27:56+00:00

... instead of open-coding the call of ->read() Signed-off-by: Al Viro

mm/nommu.c: export symbol max_mapnr

2015-03-13T01:46:08+00:00

Several modules may need max_mapnr, so export, the related error with allmodconfig under c6x: MODPOST 3327 modules ERROR: "max_mapnr" [fs/pstore/ramoops.ko] undefined! ERROR: "max_mapnr" [drivers/media/v4l2-core/videobuf2-dma-contig.ko] undefined! Signed-off-by: Chen Gang Cc: Mark Salter Cc: Aurelien Jacquiot Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm/nommu: fix memory leak

2015-02-28T17:57:50+00:00

Maxime reported the following memory leak regression due to commit dbc8358c7237 ("mm/nommu: use alloc_pages_exact() rather than its own implementation"). On v3.19, I am facing a memory leak. Each time I run a command one page is lost. Here an example with busybox's free command: / # free total used free shared buffers cached Mem: 7928 1972 5956 0 0 492 -/+ buffers/cache: 1480 6448 / # free total used free shared buffers cached Mem: 7928 1976 5952 0 0 492 -/+ buffers/cache: 1484 6444 / # free total used free shared buffers cached Mem: 7928 1980 5948 0 0 492 -/+ buffers/cache: 1488 6440 / # free total used free shared buffers cached Mem: 7928 1984 5944 0 0 492 -/+ buffers/cache: 1492 6436 / # free total used free shared buffers cached Mem: 7928 1988 5940 0 0 492 -/+ buffers/cache: 1496 6432 At some point, the system fails to sastisfy 256KB allocations: free: page allocation failure: order:6, mode:0xd0 CPU: 0 PID: 67 Comm: free Not tainted 3.19.0-05389-gacf2cf1-dirty #64 Hardware name: STM32 (Device Tree Support) show_stack+0xb/0xc warn_alloc_failed+0x97/0xbc __alloc_pages_nodemask+0x295/0x35c __get_free_pages+0xb/0x24 alloc_pages_exact+0x19/0x24 do_mmap_pgoff+0x423/0x658 vm_mmap_pgoff+0x3f/0x4e load_flat_file+0x20d/0x4f8 load_flat_binary+0x3f/0x26c search_binary_handler+0x51/0xe4 do_execveat_common+0x271/0x35c do_execve+0x19/0x1c ret_fast_syscall+0x1/0x4a Mem-info: Normal per-cpu: CPU 0: hi: 0, btch: 1 usd: 0 active_anon:0 inactive_anon:0 isolated_anon:0 active_file:0 inactive_file:0 isolated_file:0 unevictable:123 dirty:0 writeback:0 unstable:0 free:1515 slab_reclaimable:17 slab_unreclaimable:139 mapped:0 shmem:0 pagetables:0 bounce:0 free_cma:0 Normal free:6060kB min:352kB low:440kB high:528kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:492kB isolated(anon):0ks lowmem_reserve[]: 0 0 Normal: 23*4kB (U) 22*8kB (U) 24*16kB (U) 23*32kB (U) 23*64kB (U) 23*128kB (U) 1*256kB (U) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 6060kB 123 total pagecache pages 2048 pages of RAM 1538 free pages 66 reserved pages 109 slab pages -46 pages shared 0 pages swap cached nommu: Allocation of length 221184 from process 67 (free) failed Normal per-cpu: CPU 0: hi: 0, btch: 1 usd: 0 active_anon:0 inactive_anon:0 isolated_anon:0 active_file:0 inactive_file:0 isolated_file:0 unevictable:123 dirty:0 writeback:0 unstable:0 free:1515 slab_reclaimable:17 slab_unreclaimable:139 mapped:0 shmem:0 pagetables:0 bounce:0 free_cma:0 Normal free:6060kB min:352kB low:440kB high:528kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:492kB isolated(anon):0ks lowmem_reserve[]: 0 0 Normal: 23*4kB (U) 22*8kB (U) 24*16kB (U) 23*32kB (U) 23*64kB (U) 23*128kB (U) 1*256kB (U) 0*512kB 0*1024kB 0*2048kB 0*4096kB = 6060kB 123 total pagecache pages Unable to allocate RAM for process text/data, errno 12 SEGV This problem happens because we allocate ordered page through __get_free_pages() in do_mmap_private() in some cases and we try to free individual pages rather than ordered page in free_page_series(). In this case, freeing pages whose refcount is not 0 won't be freed to the page allocator so memory leak happens. To fix the problem, this patch changes __get_free_pages() to alloc_pages_exact() since alloc_pages_exact() returns physically-contiguous pages but each pages are refcounted. Fixes: dbc8358c7237 ("mm/nommu: use alloc_pages_exact() rather than its own implementation"). Reported-by: Maxime Coquelin Tested-by: Maxime Coquelin Signed-off-by: Joonsoo Kim Cc: [3.19] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Merge branch 'for-3.20/bdi' of git://git.kernel.dk/linux-block

2015-02-12T21:50:21+00:00

Pull backing device changes from Jens Axboe: "This contains a cleanup of how the backing device is handled, in preparation for a rework of the life time rules. In this part, the most important change is to split the unrelated nommu mmap flags from it, but also removing a backing_dev_info pointer from the address_space (and inode), and a cleanup of other various minor bits. Christoph did all the work here, I just fixed an oops with pages that have a swap backing. Arnd fixed a missing export, and Oleg killed the lustre backing_dev_info from staging. Last patch was from Al, unexporting parts that are now no longer needed outside" * 'for-3.20/bdi' of git://git.kernel.dk/linux-block: Make super_blocks and sb_lock static mtd: export new mtd_mmap_capabilities fs: make inode_to_bdi() handle NULL inode staging/lustre/llite: get rid of backing_dev_info fs: remove default_backing_dev_info fs: don't reassign dirty inodes to default_backing_dev_info nfs: don't call bdi_unregister ceph: remove call to bdi_unregister fs: remove mapping->backing_dev_info fs: export inode_to_bdi and use it in favor of mapping->backing_dev_info nilfs2: set up s_bdi like the generic mount_bdev code block_dev: get bdev inode bdi directly from the block device block_dev: only write bdev inode on close fs: introduce f_op->mmap_capabilities for nommu mmap support fs: kill BDI_CAP_SWAP_BACKED fs: deduplicate noop_backing_dev_info

mm/nommu.c: fix arithmetic overflow in __vm_enough_memory()

2015-02-12T01:06:07+00:00

I noticed that "allowed" can easily overflow by falling below 0, because (total_vm / 32) can be larger than "allowed". The problem occurs in OVERCOMMIT_NONE mode. In this case, a huge allocation can success and overcommit the system (despite OVERCOMMIT_NONE mode). All subsequent allocations will fall (system-wide), so system become unusable. The problem was masked out by commit c9b1d0981fcc ("mm: limit growth of 3% hardcoded other user reserve"), but it's easy to reproduce it on older kernels: 1) set overcommit_memory sysctl to 2 2) mmap() large file multiple times (with VM_SHARED flag) 3) try to malloc() large amount of memory It also can be reproduced on newer kernels, but miss-configured sysctl_user_reserve_kbytes is required. Fix this issue by switching to signed arithmetic here. Signed-off-by: Roman Gushchin Cc: Andrew Shewmaker Cc: Rik van Riel Cc: Konstantin Khlebnikov Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: gup: add __get_user_pages_unlocked to customize gup_flags

2015-02-12T01:06:05+00:00

Some callers (like KVM) may want to set the gup_flags like FOLL_HWPOSION to get a proper -EHWPOSION retval instead of -EFAULT to take a more appropriate action if get_user_pages runs into a memory failure. Signed-off-by: Andrea Arcangeli Reviewed-by: Kirill A. Shutemov Cc: Andres Lagar-Cavilla Cc: Peter Feiner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: gup: add get_user_pages_locked and get_user_pages_unlocked

2015-02-12T01:06:05+00:00

FAULT_FOLL_ALLOW_RETRY allows the page fault to drop the mmap_sem for reading to reduce the mmap_sem contention (for writing), like while waiting for I/O completion. The problem is that right now practically no get_user_pages call uses FAULT_FOLL_ALLOW_RETRY, so we're not leveraging that nifty feature. Andres fixed it for the KVM page fault. However get_user_pages_fast remains uncovered, and 99% of other get_user_pages aren't using it either (the only exception being FOLL_NOWAIT in KVM which is really nonblocking and in fact it doesn't even release the mmap_sem). So this patchsets extends the optimization Andres did in the KVM page fault to the whole kernel. It makes most important places (including gup_fast) to use FAULT_FOLL_ALLOW_RETRY to reduce the mmap_sem hold times during I/O. The only few places that remains uncovered are drivers like v4l and other exceptions that tends to work on their own memory and they're not working on random user memory (for example like O_DIRECT that uses gup_fast and is fully covered by this patch). A follow up patch should probably also add a printk_once warning to get_user_pages that should go obsolete and be phased out eventually. The "vmas" parameter of get_user_pages makes it fundamentally incompatible with FAULT_FOLL_ALLOW_RETRY (vmas array becomes meaningless the moment the mmap_sem is released). While this is just an optimization, this becomes an absolute requirement for the userfaultfd feature http://lwn.net/Articles/615086/ . The userfaultfd allows to block the page fault, and in order to do so I need to drop the mmap_sem first. So this patch also ensures that all memory where userfaultfd could be registered by KVM, the very first fault (no matter if it is a regular page fault, or a get_user_pages) always has FAULT_FOLL_ALLOW_RETRY set. Then the userfaultfd blocks and it is waken only when the pagetable is already mapped. The second fault attempt after the wakeup doesn't need FAULT_FOLL_ALLOW_RETRY, so it's ok to retry without it. This patch (of 5): We can leverage the VM_FAULT_RETRY functionality in the page fault paths better by using either get_user_pages_locked or get_user_pages_unlocked. The former allows conversion of get_user_pages invocations that will have to pass a "&locked" parameter to know if the mmap_sem was dropped during the call. Example from: down_read(&mm->mmap_sem); do_something() get_user_pages(tsk, mm, ..., pages, NULL); up_read(&mm->mmap_sem); to: int locked = 1; down_read(&mm->mmap_sem); do_something() get_user_pages_locked(tsk, mm, ..., pages, &locked); if (locked) up_read(&mm->mmap_sem); The latter is suitable only as a drop in replacement of the form: down_read(&mm->mmap_sem); get_user_pages(tsk, mm, ..., pages, NULL); up_read(&mm->mmap_sem); into: get_user_pages_unlocked(tsk, mm, ..., pages); Where tsk, mm, the intermediate "..." paramters and "pages" can be any value as before. Just the last parameter of get_user_pages (vmas) must be NULL for get_user_pages_locked|unlocked to be usable (the latter original form wouldn't have been safe anyway if vmas wasn't null, for the former we just make it explicit by dropping the parameter). If vmas is not NULL these two methods cannot be used. Signed-off-by: Andrea Arcangeli Reviewed-by: Andres Lagar-Cavilla Reviewed-by: Peter Feiner Reviewed-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds