path: root/mm/filemap.c
AgeCommit message (Collapse)Author
2010-03-06mm: use rlimit helpersJiri Slaby
Make sure compiler won't do weird things with limits. E.g. fetching them twice may return 2 different values after writable limits are implemented. I.e. either use rlimit helpers added in 3e10e716abf3c71bdb5d86b8f507f9e72236c9cd ("resource: add helpers for fetching rlimits") or ACCESS_ONCE if not applicable. Signed-off-by: Jiri Slaby <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2010-03-03kill unused invalidate_inode_pages helperChristoph Hellwig
No one is calling this anymore as everyone has switched to invalidate_mapping_pages long time ago. Also update a few references to it in comments. nfs has two more, but I can't easily figure what they are actually referring to, so I left them as-is. Signed-off-by: Christoph Hellwig <> Signed-off-by: Al Viro <>
2010-02-02mm: flush dcache before writing into page to avoid aliasanfei zhou
The cache alias problem will happen if the changes of user shared mapping is not flushed before copying, then user and kernel mapping may be mapped into two different cache line, it is impossible to guarantee the coherence after iov_iter_copy_from_user_atomic. So the right steps should be: flush_dcache_page(page); kmap_atomic(page); write to page; kunmap_atomic(page); flush_dcache_page(page); More precisely, we might create two new APIs flush_dcache_user_page and flush_dcache_kern_page to replace the two flush_dcache_page accordingly. Here is a snippet tested on omap2430 with VIPT cache, and I think it is not ARM-specific: int val = 0x11111111; fd = open("abc", O_RDWR); addr = mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0); *(addr+0) = 0x44444444; tmp = *(addr+0); *(addr+1) = 0x77777777; write(fd, &val, sizeof(int)); close(fd); The results are not always 0x11111111 0x77777777 at the beginning as expected. Sometimes we see 0x44444444 0x77777777. Signed-off-by: Anfei <> Cc: Russell King <> Cc: Miklos Szeredi <> Cc: Nick Piggin <> Cc: <> Cc: <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2010-01-27mm: add new 'read_cache_page_gfp()' helper functionLinus Torvalds
It's a simplified 'read_cache_page()' which takes a page allocation flag, so that different paths can control how aggressive the memory allocations are that populate a address space. In particular, the intel GPU object mapping code wants to be able to do a certain amount of own internal memory management by automatically shrinking the address space when memory starts getting tight. This allows it to dynamically use different memory allocation policies on a per-allocation basis, rather than depend on the (static) address space gfp policy. The actual new function is a one-liner, but re-organizing the helper functions to the point where you can do this with a single line of code is what most of the patch is all about. Tested-by: Chris Wilson <> Signed-off-by: Linus Torvalds <>
2009-12-16direct I/O fallback sync simplificationChristoph Hellwig
In the case of direct I/O falling back to buffered I/O we sync data twice currently: once at the end of generic_file_buffered_write using filemap_write_and_wait_range and once a little later in __generic_file_aio_write using do_sync_mapping_range with all flags set. The wait before write of the do_sync_mapping_range call does not make any sense, so just keep the filemap_write_and_wait_range call and move it to the right spot. Signed-off-by: Christoph Hellwig <> Signed-off-by: Al Viro <>
2009-12-10kill wait_on_page_writeback_rangeChristoph Hellwig
All callers really want the more logical filemap_fdatawait_range interface, so convert them to use it and merge wait_on_page_writeback_range into filemap_fdatawait_range. Signed-off-by: Christoph Hellwig <> Signed-off-by: Jan Kara <>
2009-12-04tree-wide: fix assorted typos all over the placeAndré Goddard Rosa
That is "success", "unknown", "through", "performance", "[re|un]mapping" , "access", "default", "reasonable", "[con]currently", "temperature" , "channel", "[un]used", "application", "example","hierarchy", "therefore" , "[over|under]flow", "contiguous", "threshold", "enough" and others. Signed-off-by: André Goddard Rosa <> Signed-off-by: Jiri Kosina <>
2009-09-27const: mark struct vm_struct_operationsAlexey Dobriyan
* mark struct vm_area_struct::vm_ops as const * mark vm_ops in AGP code But leave TTM code alone, something is fishy there with global vm_ops being used. Signed-off-by: Alexey Dobriyan <> Signed-off-by: Linus Torvalds <>
2009-09-24Merge branch 'for-linus' of ↵Linus Torvalds
git:// * 'for-linus' of git:// truncate: use new helpers truncate: new helpers fs: fix overflow in sys_mount() for in-kernel calls fs: Make unload_nls() NULL pointer safe freeze_bdev: grab active reference to frozen superblocks freeze_bdev: kill bd_mount_sem exofs: remove BKL from super operations fs/romfs: correct error-handling code vfs: seq_file: add helpers for data filling vfs: remove redundant position check in do_sendfile vfs: change sb->s_maxbytes to a loff_t vfs: explicitly cast s_maxbytes in fiemap_check_ranges libfs: return error code on failed attr set seq_file: return a negative error code when seq_path_root() fails. vfs: optimize touch_time() too vfs: optimization for touch_atime() vfs: split generic_forget_inode() so that hugetlbfs does not have to copy it fs/inode.c: add dev-id and inode number for debugging in init_special_inode() libfs: make simple_read_from_buffer conventional
2009-09-24Merge branch 'hwpoison' of ↵Linus Torvalds
git:// * 'hwpoison' of git:// (21 commits) HWPOISON: Enable error_remove_page on btrfs HWPOISON: Add simple debugfs interface to inject hwpoison on arbitary PFNs HWPOISON: Add madvise() based injector for hardware poisoned pages v4 HWPOISON: Enable error_remove_page for NFS HWPOISON: Enable .remove_error_page for migration aware file systems HWPOISON: The high level memory error handler in the VM v7 HWPOISON: Add PR_MCE_KILL prctl to control early kill behaviour per process HWPOISON: shmem: call set_page_dirty() with locked page HWPOISON: Define a new error_remove_page address space op for async truncation HWPOISON: Add invalidate_inode_page HWPOISON: Refactor truncate to allow direct truncating of page v2 HWPOISON: check and isolate corrupted free pages v2 HWPOISON: Handle hardware poisoned pages in try_to_unmap HWPOISON: Use bitmask/action code for try_to_unmap behaviour HWPOISON: x86: Add VM_FAULT_HWPOISON handling to x86 page fault handler v2 HWPOISON: Add poison check to page fault handling HWPOISON: Add basic support for poisoned pages in fault handler v3 HWPOISON: Add new SIGBUS error codes for hardware poison signals HWPOISON: Add support for poison swap entries v2 HWPOISON: Export some rmap vma locking to outside world ...
2009-09-24truncate: new
Introduce new truncate helpers truncate_pagecache and inode_newsize_ok. vmtruncate is also consolidated from mm/memory.c and mm/nommu.c and into mm/truncate.c. Reviewed-by: Christoph Hellwig <> Signed-off-by: Nick Piggin <> Signed-off-by: Al Viro <>
2009-09-22mm: oom analysis: add shmem vmstatKOSAKI Motohiro
Recently we encountered OOM problems due to memory use of the GEM cache. Generally a large amuont of Shmem/Tmpfs pages tend to create a memory shortage problem. We often use the following calculation to determine the amount of shmem pages: shmem = NR_ACTIVE_ANON + NR_INACTIVE_ANON - NR_ANON_PAGES however the expression does not consider isolated and mlocked pages. This patch adds explicit accounting for pages used by shmem and tmpfs. Signed-off-by: KOSAKI Motohiro <> Acked-by: Rik van Riel <> Reviewed-by: Christoph Lameter <> Acked-by: Wu Fengguang <> Cc: David Rientjes <> Cc: Hugh Dickins <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-09-16HWPOISON: The high level memory error handler in the VM v7Andi Kleen
Add the high level memory handler that poisons pages that got corrupted by hardware (typically by a two bit flip in a DIMM or a cache) on the Linux level. The goal is to prevent everyone from accessing these pages in the future. This done at the VM level by marking a page hwpoisoned and doing the appropriate action based on the type of page it is. The code that does this is portable and lives in mm/memory-failure.c To quote the overview comment: High level machine check handler. Handles pages reported by the hardware as being corrupted usually due to a 2bit ECC memory or cache failure. This focuses on pages detected as corrupted in the background. When the current CPU tries to consume corruption the currently running process can just be killed directly instead. This implies that if the error cannot be handled for some reason it's safe to just ignore it because no corruption has been consumed yet. Instead when that happens another machine check will happen. Handles page cache pages in various states. The tricky part here is that we can access any page asynchronous to other VM users, because memory failures could happen anytime and anywhere, possibly violating some of their assumptions. This is why this code has to be extremely careful. Generally it tries to use normal locking rules, as in get the standard locks, even if that means the error handling takes potentially a long time. Some of the operations here are somewhat inefficient and have non linear algorithmic complexity, because the data structures have not been optimized for this case. This is in particular the case for the mapping from a vma to a process. Since this case is expected to be rare we hope we can get away with this. There are in principle two strategies to kill processes on poison: - just unmap the data and wait for an actual reference before killing - kill as soon as corruption is detected. Both have advantages and disadvantages and should be used in different situations. Right now both are implemented and can be switched with a new sysctl vm.memory_failure_early_kill The default is early kill. The patch does some rmap data structure walking on its own to collect processes to kill. This is unusual because normally all rmap data structure knowledge is in rmap.c only. I put it here for now to keep everything together and rmap knowledge has been seeping out anyways Includes contributions from Johannes Weiner, Chris Mason, Fengguang Wu, Nick Piggin (who did a lot of great work) and others. Cc: Cc: Signed-off-by: Andi Kleen <> Acked-by: Rik van Riel <> Reviewed-by: Hidehiro Kawai <>
2009-09-14vfs: Remove generic_osync_inode() and sync_page_range{_nolock}()Jan Kara
Remove these three functions since nobody uses them anymore. Signed-off-by: Jan Kara <>
2009-09-14vfs: Introduce new helpers for syncing after writing to O_SYNC file or ↵Jan Kara
IS_SYNC inode Introduce new function for generic inode syncing (vfs_fsync_range) and use it from fsync() path. Introduce also new helper for syncing after a sync write (generic_write_sync) using the generic function. Use these new helpers for syncing from generic VFS functions. This makes O_SYNC writes to block devices acquire i_mutex for syncing. If we really care about this, we can make block_fsync() drop the i_mutex and reacquire it before it returns. CC: Evgeniy Polyakov <> CC: CC: Joel Becker <> CC: Felix Blyakher <> CC: CC: Anton Altaparmakov <> CC: CC: OGAWA Hirofumi <> CC: CC: Acked-by: Christoph Hellwig <> Signed-off-by: Jan Kara <>
2009-09-14vfs: Rename generic_file_aio_write_nolockChristoph Hellwig
generic_file_aio_write_nolock() is now used only by block devices and raw character device. Filesystems should use __generic_file_aio_write() in case generic_file_aio_write() doesn't suit them. So rename the function to blkdev_aio_write() and move it to fs/blockdev.c. Signed-off-by: Christoph Hellwig <> Signed-off-by: Jan Kara <>
2009-09-14vfs: Remove syncing from generic_file_direct_write() and ↵Jan Kara
generic_file_buffered_write() generic_file_direct_write() and generic_file_buffered_write() called generic_osync_inode() if it was called on O_SYNC file or IS_SYNC inode. But this is superfluous since generic_file_aio_write() does the syncing as well. Also XFS and OCFS2 which call these functions directly handle syncing themselves. So let's have a single place where syncing happens: generic_file_aio_write(). We slightly change the behavior by syncing only the range of file to which the write happened for buffered writes but that should be all that is required. CC: CC: Joel Becker <> CC: Felix Blyakher <> CC: Signed-off-by: Jan Kara <>
2009-09-14vfs: Export __generic_file_aio_write() and add some commentsJan Kara
Rename __generic_file_aio_write_nolock() to __generic_file_aio_write(), add comments to write helpers explaining how they should be used and export __generic_file_aio_write() since it will be used by some filesystems. CC: CC: Joel Becker <> Acked-by: Evgeniy Polyakov <> Reviewed-by: Christoph Hellwig <> Signed-off-by: Jan Kara <>
2009-09-14vfs: Introduce filemap_fdatawait_rangeJan Kara
This simple helper saves some filesystems conversion from byte offset to page numbers and also makes the fdata* interface more complete. Reviewed-by: Christoph Hellwig <> Signed-off-by: Jan Kara <>
2009-07-06mm: mark page accessed before we write_end()Josef Bacik
In testing a backport of the write_begin/write_end AOPs, a 10% re-read regression was noticed when running iozone. This regression was introduced because the old AOPs would always do a mark_page_accessed(page) after the commit_write, but when the new AOPs where introduced, the only place this was kept was in pagecache_write_end(). This patch does the same thing in the generic case as what is done in pagecache_write_end(), which is just to mark the page accessed before we do write_end(). Signed-off-by: Josef Bacik <> Acked-by: Nick Piggin <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16page allocator: do not check NUMA node ID when the caller knows the node is ↵Mel Gorman
valid Callers of alloc_pages_node() can optionally specify -1 as a node to mean "allocate from the current node". However, a number of the callers in fast paths know for a fact their node is valid. To avoid a comparison and branch, this patch adds alloc_pages_exact_node() that only checks the nid with VM_BUG_ON(). Callers that know their node is valid are then converted. Signed-off-by: Mel Gorman <> Reviewed-by: Christoph Lameter <> Reviewed-by: KOSAKI Motohiro <> Reviewed-by: Pekka Enberg <> Acked-by: Paul Mundt <> [for the SLOB NUMA bits] Cc: Peter Zijlstra <> Cc: Nick Piggin <> Cc: Dave Hansen <> Cc: Lee Schermerhorn <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16readahead: enforce full sync mmap readahead sizeWu Fengguang
Now that we do readahead for sequential mmap reads, here is a simple evaluation of the impacts, and one further optimization. It's an NFS-root debian desktop system, readahead size = 60 pages. The numbers are grabbed after a fresh boot into console. approach pgmajfault RA miss ratio mmap IO count avg IO size(pages) A 383 31.6% 383 11 B 225 32.4% 390 11 C 224 32.6% 307 13 case A: mmap sync/async readahead disabled case B: mmap sync/async readahead enabled, with enforced full async readahead size case C: mmap sync/async readahead enabled, with enforced full sync/async readahead size or: A = vanilla 2.6.30-rc1 B = A plus mmap readahead C = B plus this patch The numbers show that - there are good possibilities for random mmap reads to trigger readahead - 'pgmajfault' is reduced by 1/3, due to the _async_ nature of readahead - case C can further reduce IO count by 1/4 - readahead miss ratios are not quite affected The theory is - readahead is _good_ for clustered random reads, and can perform _better_ than readaround because they could be _async_. - async readahead size is guaranteed to be larger than readaround size, and they are _async_, hence will mostly behave better However for B - sync readahead size could be smaller than readaround size, hence may make things worse by produce more smaller IOs which will be fixed by this patch. Final conclusion: - mmap readahead reduced major faults by 1/3 and no obvious overheads; - mmap io can be further reduced by 1/4 with this patch. Signed-off-by: Wu Fengguang <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16readahead: remove redundant test in shrink_readahead_size_eio()Wu Fengguang
Signed-off-by: Wu Fengguang <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16readahead: record mmap read-around states in file_ra_stateWu Fengguang
Mmap read-around now shares the same code style and data structure with readahead code. This also removes do_page_cache_readahead(). Its last user, mmap read-around, has been changed to call ra_submit(). The no-readahead-if-congested logic is dumped by the way. Users will be pretty sensitive about the slow loading of executables. So it's unfavorable to disabled mmap read-around on a congested queue. [ coding-style fixes] Cc: Nick Piggin <> Signed-off-by: Fengguang Wu <> Cc: Ying Han <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16readahead: enforce full readahead size on async mmap readaheadWu Fengguang
We need this in one particular case and two more general ones. Now we do async readahead for sequential mmap reads, and do it with the help of PG_readahead. For normal reads, PG_readahead is the sufficient condition to do a sequential readahead. But unfortunately, for mmap reads, there is a tiny nuisance: [11736.998347] readahead-init0(process: sh/23926, file: sda1/w3m, offset=0:4503599627370495, ra=0+4-3) = 4 [11737.014985] readahead-around(process: w3m/23926, file: sda1/w3m, offset=0:0, ra=290+32-0) = 17 [11737.019488] readahead-around(process: w3m/23926, file: sda1/w3m, offset=0:0, ra=118+32-0) = 32 [11737.024921] readahead-interleaved(process: w3m/23926, file: sda1/w3m, offset=0:2, ra=4+6-6) = 6 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~ An unfavorably small readahead. The original dumb read-around size could be more efficient. That happened because does a read(832) in L1 before mmap(), which triggers a 4-page readahead, with the second page tagged PG_readahead. L0: open("/lib/", O_RDONLY) = 3 L1: read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0\340\342"..., 832) = 832 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ L2: fstat(3, {st_mode=S_IFREG|0755, st_size=1420624, ...}) = 0 L3: mmap(NULL, 3527256, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x7fac6e51d000 L4: mprotect(0x7fac6e671000, 2097152, PROT_NONE) = 0 L5: mmap(0x7fac6e871000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x154000) = 0x7fac6e871000 L6: mmap(0x7fac6e876000, 16984, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x7fac6e876000 L7: close(3) = 0 In general, the PG_readahead flag will also be hit in cases - sequential reads - clustered random reads A full readahead size is desirable in both cases. Cc: Nick Piggin <> Signed-off-by: Wu Fengguang <> Cc: Ying Han <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16readahead: sequential mmap readaheadWu Fengguang
Auto-detect sequential mmap reads and do readahead for them. The sequential mmap readahead will be triggered when - sync readahead: it's a major fault and (prev_offset == offset-1); - async readahead: minor fault on PG_readahead page with valid readahead state. The benefits of doing readahead instead of read-around: - less I/O wait thanks to async readahead - double real I/O size and no more cache hits The single stream case is improved a little. For 100,000 sequential mmap reads: user system cpu total (1-1) plain -mm, 128KB readaround: 3.224 2.554 48.40% 11.838 (1-2) plain -mm, 256KB readaround: 3.170 2.392 46.20% 11.976 (2) patched -mm, 128KB readahead: 3.117 2.448 47.33% 11.607 The patched (2) has smallest total time, since it has no cache hit overheads and less I/O block time(thanks to async readahead). Here the I/O size makes no much difference, since there's only one single stream. Note that (1-1)'s real I/O size is 64KB and (1-2)'s real I/O size is 128KB, since the half of the read-around pages will be readahead cache hits. This is going to make _real_ differences for _concurrent_ IO streams. Cc: Nick Piggin <> Signed-off-by: Wu Fengguang <> Cc: Ying Han <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16readahead: clean up and simplify the code for filemap page fault readaheadLinus Torvalds
This shouldn't really change behavior all that much, but the single rather complex function with read-ahead inside a loop etc is broken up into more manageable pieces. The behaviour is also less subtle, with the read-ahead being done up-front rather than inside some subtle loop and thus avoiding the now unnecessary extra state variables (ie "did_readaround" is gone). Fengguang: the code split in fact fixed a bug reported by Pavel Levshin: the PGMAJFAULT accounting used to be bypassed when MADV_RANDOM is set, in which case the original code will directly jump to no_cached_page reading. Cc: Pavel Levshin <> Cc: <> Cc: Nick Piggin <> Signed-off-by: Wu Fengguang <> Signed-off-by: Linus Torvalds <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-06-16readahead: move max_sane_readahead() calls into force_page_cache_readahead()Wu Fengguang
Impact: code simplification. Cc: Nick Piggin <> Signed-off-by: Wu Fengguang <> Cc: Ying Han <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-05-29memcg: fix deadlock between lock_page_cgroup and mapping tree_lockDaisuke Nishimura
mapping->tree_lock can be acquired from interrupt context. Then, following dead lock can occur. Assume "A" as a page. CPU0: lock_page_cgroup(A) interrupted -> take mapping->tree_lock. CPU1: take mapping->tree_lock -> lock_page_cgroup(A) This patch tries to fix above deadlock by moving memcg's hook to out of mapping->tree_lock. charge/uncharge of pagecache/swapcache is protected by page lock, not tree_lock. After this patch, lock_page_cgroup() is not called under mapping->tree_lock. Signed-off-by: KAMEZAWA Hiroyuki <> Signed-off-by: Daisuke Nishimura <> Cc: Balbir Singh <> Cc: Daisuke Nishimura <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-04-16Export filemap_write_and_wait_rangeChris Mason
This wasn't exported before and is useful (used by the experimental ext3 data=guarded code) Signed-off-by: Chris Mason <> Acked-by: Theodore Tso <> Acked-by: Jan Kara <> Signed-off-by: Linus Torvalds <>
2009-04-13filemap: fix kernel-doc warningsRandy Dunlap
Fix filemap.c kernel-doc warnings: Warning(mm/filemap.c:575): No description found for parameter 'page' Warning(mm/filemap.c:575): No description found for parameter 'waiter' Signed-off-by: Randy Dunlap <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-04-03Staging: pohmelfs: kconfig/makefile and vfs changes.Evgeniy Polyakov
This patch adds Kconfig and Makefile entries and exports to VFS functions to be used by POHMELFS. Signed-off-by: Evgeniy Polyakov <> Signed-off-by: Greg Kroah-Hartman <>
2009-04-03CacheFiles: Permit the page lock state to be monitoredDavid Howells
Add a function to install a monitor on the page lock waitqueue for a particular page, thus allowing the page being unlocked to be detected. This is used by CacheFiles to detect read completion on a page in the backing filesystem so that it can then copy the data to the waiting netfs page. Signed-off-by: David Howells <> Acked-by: Steve Dickson <> Acked-by: Trond Myklebust <> Acked-by: Rik van Riel <> Acked-by: Al Viro <> Tested-by: Daire Byrne <>
2009-04-03FS-Cache: Recruit a page flags for cache managementDavid Howells
Recruit a page flag to aid in cache management. The following extra flag is defined: (1) PG_fscache (PG_private_2) The marked page is backed by a local cache and is pinning resources in the cache driver. If PG_fscache is set, then things that checked for PG_private will now also check for that. This includes things like truncation and page invalidation. The function page_has_private() had been added to make the checks for both PG_private and PG_private_2 at the same time. Signed-off-by: David Howells <> Acked-by: Steve Dickson <> Acked-by: Trond Myklebust <> Acked-by: Rik van Riel <> Acked-by: Al Viro <> Tested-by: Daire Byrne <>
2009-03-02x86, mm: dont use non-temporal stores in pagecache accessesIngo Molnar
Impact: standardize IO on cached ops On modern CPUs it is almost always a bad idea to use non-temporal stores, as the regression in this commit has shown it: 30d697f: x86: fix performance regression in write() syscall The kernel simply has no good information about whether using non-temporal stores is a good idea or not - and trying to add heuristics only increases complexity and inserts fragility. The regression on cached write()s took very long to be found - over two years. So dont take any chances and let the hardware decide how it makes use of its caches. The only exception is drivers/gpu/drm/i915/i915_gem.c: there were we are absolutely sure that another entity (the GPU) will pick up the dirty data immediately and that the CPU will not touch that data before the GPU will. Also, keep the _nocache() primitives to make it easier for people to experiment with these details. There may be more clear-cut cases where non-cached copies can be used, outside of filemap.c. Cc: Salman Qazi <> Cc: Nick Piggin <> Cc: Linus Torvalds <> Signed-off-by: Ingo Molnar <>
2009-02-25x86, mm: pass in 'total' to __copy_from_user_*nocache()Ingo Molnar
Impact: cleanup, enable future change Add a 'total bytes copied' parameter to __copy_from_user_*nocache(), and update all the callsites. The parameter is not used yet - architecture code can use it to more intelligently decide whether the copy should be cached or non-temporal. Cc: Salman Qazi <> Cc: Nick Piggin <> Cc: Linus Torvalds <> Signed-off-by: Ingo Molnar <>
2009-01-14[CVE-2009-0029] System call wrapper special casesHeiko Carstens
System calls with an unsigned long long argument can't be converted with the standard wrappers since that would include a cast to long, which in turn means that we would lose the upper 32 bit on 32 bit architectures. Also semctl can't use the standard wrapper since it has a 'union' parameter. So we handle them as special case and add some extra wrappers instead. Signed-off-by: Heiko Carstens <>
2009-01-14[CVE-2009-0029] Convert all system calls to return a longHeiko Carstens
Convert all system calls to return a long. This should be a NOP since all converted types should have the same size anyway. With the exception of sys_exit_group which returned void. But that doesn't matter since the system call doesn't return. Signed-off-by: Heiko Carstens <>
2009-01-08memcg: revert gfp mask fixKAMEZAWA Hiroyuki
My patch, memcg-fix-gfp_mask-of-callers-of-charge.patch changed gfp_mask of callers of charge to be GFP_HIGHUSER_MOVABLE for showing what will happen at memory reclaim. But in recent discussion, it's NACKed because it sounds ugly. This patch is for reverting it and add some clean up to gfp_mask of callers of charge. No behavior change but need review before generating HUNK in deep queue. This patch also adds explanation to meaning of gfp_mask passed to charge functions in memcontrol.h. Signed-off-by: KAMEZAWA Hiroyuki <> Cc: Balbir Singh <> Cc: Daisuke Nishimura <> Cc: Hugh Dickins <> Cc: KOSAKI Motohiro <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-01-06mm: pagecache gfp flags fixNick Piggin
Frustratingly, gfp_t is really divided into two classes of flags. One are the context dependent ones (can we sleep? can we enter filesystem? block subsystem? should we use some extra reserves, etc.). The other ones are the type of memory required and depend on how the algorithm is implemented rather than the point at which the memory is allocated (highmem? dma memory? etc). Some of the functions which allocate a page and add it to page cache take a gfp_t, but sometimes those functions or their callers aren't really doing the right thing: when allocating pagecache page, the memory type should be mapping_gfp_mask(mapping). When allocating radix tree nodes, the memory type should be kernel mapped (not highmem) memory. The gfp_t argument should only really be needed for context dependent options. This patch doesn't really solve that tangle in a nice way, but it does attempt to fix a couple of bugs. - find_or_create_page changes its radix-tree allocation to only include the main context dependent flags in order so the pagecache page may be allocated from arbitrary types of memory without affecting the radix-tree. In practice, slab allocations don't come from highmem anyway, and radix-tree only uses slab allocations. So there isn't a practical change (unless some fs uses GFP_DMA for pages). - grab_cache_page_nowait() is changed to allocate radix-tree nodes with GFP_NOFS, because it is not supposed to reenter the filesystem. This bug could cause lock recursion if a filesystem is not expecting the function to reenter the fs (as-per documentation). Filesystems should be careful about exactly what semantics they want and what they get when fiddling with gfp_t masks to allocate pagecache. One should be as liberal as possible with the type of memory that can be used, and same for the the context specific flags. Signed-off-by: Nick Piggin <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-01-06mm: direct IO starvation improvementNick Piggin
Direct IO can invalidate and sync a lot of pagecache pages in the mapping. A 4K direct IO will actually try to sync and/or invalidate the pagecache of the entire file, for example (which might be many GB or TB large). Improve this by doing range syncs. Also, memory no longer has to be unmapped to catch the dirty bits for syncing, as dirty bits would remain coherent due to dirty mmap accounting. This fixes the immediate DM deadlocks when doing direct IO reads to block device with a mounted filesystem, if only by papering over the problem somewhat rather than addressing the fsync starvation cases. Signed-off-by: Nick Piggin <> Reviewed-by: Jeff Moyer <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-01-06mm: write_cache_pages integrity fixNick Piggin
In write_cache_pages, nr_to_write is heeded even for data-integrity syncs, so the function will return success after writing out nr_to_write pages, even if that was not sufficient to guarantee data integrity. The callers tend to set it to values that could break data interity semantics easily in practice. For example, nr_to_write can be set to mapping->nr_pages * 2, however if a file has a single, dirty page, then fsync is called, subsequent pages might be concurrently added and dirtied, then write_cache_pages might writeout two of these newly dirty pages, while not writing out the old page that should have been written out. Fix this by ignoring nr_to_write if it is a data integrity sync. This is a data integrity bug. The reason this has been done in the past is to avoid stalling sync operations behind page dirtiers. "If a file has one dirty page at offset 1000000000000000 then someone does an fsync() and someone else gets in first and starts madly writing pages at offset 0, we want to write that page at 1000000000000000. Somehow." What we do today is return success after an arbitrary amount of pages are written, whether or not we have provided the data-integrity semantics that the caller has asked for. Even this doesn't actually fix all stall cases completely: in the above situation, if the file has a huge number of pages in pagecache (but not dirty), then mapping->nrpages is going to be huge, even if pages are being dirtied. This change does indeed make the possibility of long stalls lager, and that's not a good thing, but lying about data integrity is even worse. We have to either perform the sync, or return -ELINUXISLAME so at least the caller knows what has happened. There are subsequent competing approaches in the works to solve the stall problems properly, without compromising data integrity. Signed-off-by: Nick Piggin <> Cc: Chris Mason <> Cc: Dave Chinner <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-01-06mm: don't mark_page_accessed in fault pathNick Piggin
Doing a mark_page_accessed at fault-time, then doing SetPageReferenced at unmap-time if the pte is young has a number of problems. mark_page_accessed is supposed to be roughly the equivalent of a young pte for unmapped references. Unfortunately it doesn't come with any context: after being called, reclaim doesn't know who or why the page was touched. So calling mark_page_accessed not only adds extra lru or PG_referenced manipulations for pages that are already going to have pte_young ptes anyway, but it also adds these references which are difficult to work with from the context of vma specific references (eg. MADV_SEQUENTIAL pte_young may not wish to contribute to the page being referenced). Then, simply doing SetPageReferenced when zapping a pte and finding it is young, is not a really good solution either. SetPageReferenced does not correctly promote the page to the active list for example. So after removing mark_page_accessed from the fault path, several mmap()+touch+munmap() would have a very different result from several read(2) calls for example, which is not really desirable. Signed-off-by: Nick Piggin <> Acked-by: Johannes Weiner <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-01-05Merge branch 'for-linus' of ↵Linus Torvalds
git:// * 'for-linus' of git:// inotify: fix type errors in interfaces fix breakage in reiserfs_new_inode() fix the treatment of jfs special inodes vfs: remove duplicate code in get_fs_type() add a vfs_fsync helper sys_execve and sys_uselib do not call into fsnotify zero i_uid/i_gid on inode allocation inode->i_op is never NULL ntfs: don't NULL i_op isofs check for NULL ->i_op in root directory is dead code affs: do not zero ->i_op kill suid bit only for regular files vfs: lseek(fd, 0, SEEK_CUR) race condition
2009-01-05kill suid bit only for regular filesDmitri Monakhov
We don't have to do it because it is useless for non regular files. In fact block device may trigger this path without dentry->d_inode->i_mutex. (akpm: concerns were expressed (by me) about S_ISDIR inodes) Signed-off-by: Dmitri Monakhov <> Signed-off-by: Andrew Morton <> Signed-off-by: Al Viro <>
2009-01-04fs: symlink write_begin allocation context fixNick Piggin
With the write_begin/write_end aops, page_symlink was broken because it could no longer pass a GFP_NOFS type mask into the point where the allocations happened. They are done in write_begin, which would always assume that the filesystem can be entered from reclaim. This bug could cause filesystem deadlocks. The funny thing with having a gfp_t mask there is that it doesn't really allow the caller to arbitrarily tinker with the context in which it can be called. It couldn't ever be GFP_ATOMIC, for example, because it needs to take the page lock. The only thing any callers care about is __GFP_FS anyway, so turn that into a single flag. Add a new flag for write_begin, AOP_FLAG_NOFS. Filesystems can now act on this flag in their write_begin function. Change __grab_cache_page to accept a nofs argument as well, to honour that flag (while we're there, change the name to grab_cache_page_write_begin which is more instructive and does away with random leading underscores). This is really a more flexible way to go in the end anyway -- if a filesystem happens to want any extra allocations aside from the pagecache ones in ints write_begin function, it may now use GFP_KERNEL (rather than GFP_NOFS) for common case allocations (eg. ocfs2_alloc_write_ctxt, for a random example). [ fix ubifs] [ fix fuse] Signed-off-by: Nick Piggin <> Reviewed-by: KOSAKI Motohiro <> Cc: <> [2.6.28.x] Signed-off-by: KOSAKI Motohiro <> Signed-off-by: Andrew Morton <> [ Cleaned up the calling convention: just pass in the AOP flags untouched to the grab_cache_page_write_begin() function. That just simplifies everybody, and may even allow future expansion of the logic. - Linus ] Signed-off-by: Linus Torvalds <>
2008-10-30fs: remove prepare_write/commit_writeNick Piggin
Nothing uses prepare_write or commit_write. Remove them from the tree completely. [ schedule simple_prepare_write() for unexporting] Signed-off-by: Nick Piggin <> Cc: Christoph Hellwig <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-10-20memcg: make page->mapping NULL before unchargeKAMEZAWA Hiroyuki
This patch tries to make page->mapping to be NULL before mem_cgroup_uncharge_cache_page() is called. "page->mapping == NULL" is a good check for "whether the page is still radix-tree or not". This patch also adds BUG_ON() to mem_cgroup_uncharge_cache_page(); Signed-off-by: KAMEZAWA Hiroyuki <> Reviewed-by: Daisuke Nishimura <> Cc: Balbir Singh <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-10-20mm: page lock use lock bitopsNick Piggin
trylock_page, unlock_page open and close a critical section. Hence, we can use the lock bitops to get the desired memory ordering. Also, mark trylock as likely to succeed (and remove the annotation from callers). Signed-off-by: Nick Piggin <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-10-20vmscan: split LRU lists into anon & file setsRik van Riel
Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs. The advantage of doing this is that the VM will not have to scan over lots of anonymous pages (which we generally do not want to swap out), just to find the page cache pages that it should evict. This patch has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches. [ collect lru meminfo statistics from correct offset] [ prevent incorrect oom under split_lru] [ fix pagevec_move_tail() doesn't treat unevictable page] [ memcg swapbacked pages active] [ splitlru: BDI_CAP_SWAP_BACKED] [ fix /proc/vmstat units] [ memcg: fix handling of shmem migration] [ adjust Quicklists field of /proc/meminfo] [ fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel <> Signed-off-by: Lee Schermerhorn <> Signed-off-by: KOSAKI Motohiro <> Signed-off-by: Hugh Dickins <> Signed-off-by: Daisuke Nishimura <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>