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* more conservative S_NOSEC handlingAl Viro2011-06-031-1/+1
| | | | | | | | | | | | | | | | | | | | | | Caching "we have already removed suid/caps" was overenthusiastic as merged. On network filesystems we might have had suid/caps set on another client, silently picked by this client on revalidate, all of that *without* clearing the S_NOSEC flag. AFAICS, the only reasonably sane way to deal with that is * new superblock flag; unless set, S_NOSEC is not going to be set. * local block filesystems set it in their ->mount() (more accurately, mount_bdev() does, so does btrfs ->mount(), users of mount_bdev() other than local block ones clear it) * if any network filesystem (or a cluster one) wants to use S_NOSEC, it'll need to set MS_NOSEC in sb->s_flags *AND* take care to clear S_NOSEC when inode attribute changes are picked from other clients. It's not an earth-shattering hole (anybody that can set suid on another client will almost certainly be able to write to the file before doing that anyway), but it's a bug that needs fixing. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* Cache xattr security drop check for write v2Andi Kleen2011-05-281-2/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Some recent benchmarking on btrfs showed that a major scaling bottleneck on large systems on btrfs is currently the xattr lookup on every write. Why xattr lookup on every write I hear you ask? write wants to drop suid and security related xattrs that could set o capabilities for executables. To do that it currently looks up security.capability on EVERY write (even for non executables) to decide whether to drop it or not. In btrfs this causes an additional tree walk, hitting some per file system locks and quite bad scalability. In a simple read workload on a 8S system I saw over 90% CPU time in spinlocks related to that. Chris Mason tells me this is also a problem in ext4, where it hits the global mbcache lock. This patch adds a simple per inode to avoid this problem. We only do the lookup once per file and then if there is no xattr cache the decision. All xattr changes clear the flag. I also used the same flag to avoid the suid check, although that one is pretty cheap. A file system can also set this flag when it creates the inode, if it has a cheap way to do so. This is done for some common file systems in followon patches. With this patch a major part of the lock contention disappears for btrfs. Some testing on smaller systems didn't show significant performance changes, but at least it helps the larger systems and is generally more efficient. v2: Rename is_sgid. add file system helper. Cc: chris.mason@oracle.com Cc: josef@redhat.com Cc: viro@zeniv.linux.org.uk Cc: agruen@linbit.com Cc: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mm: Wait for writeback when grabbing pages to begin a writeDarrick J. Wong2011-05-281-1/+3
| | | | | | | | | | When grabbing a page for a buffered IO write, the mm should wait for writeback on the page to complete so that the page does not become writable during the IO operation. This change is needed to provide page stability during writes for all filesystems. Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* memcg: add the pagefault count into memcg statsYing Han2011-05-261-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Two new stats in per-memcg memory.stat which tracks the number of page faults and number of major page faults. "pgfault" "pgmajfault" They are different from "pgpgin"/"pgpgout" stat which count number of pages charged/discharged to the cgroup and have no meaning of reading/ writing page to disk. It is valuable to track the two stats for both measuring application's performance as well as the efficiency of the kernel page reclaim path. Counting pagefaults per process is useful, but we also need the aggregated value since processes are monitored and controlled in cgroup basis in memcg. Functional test: check the total number of pgfault/pgmajfault of all memcgs and compare with global vmstat value: $ cat /proc/vmstat | grep fault pgfault 1070751 pgmajfault 553 $ cat /dev/cgroup/memory.stat | grep fault pgfault 1071138 pgmajfault 553 total_pgfault 1071142 total_pgmajfault 553 $ cat /dev/cgroup/A/memory.stat | grep fault pgfault 199 pgmajfault 0 total_pgfault 199 total_pgmajfault 0 Performance test: run page fault test(pft) wit 16 thread on faulting in 15G anon pages in 16G container. There is no regression noticed on the "flt/cpu/s" Sample output from pft: TAG pft:anon-sys-default: Gb Thr CLine User System Wall flt/cpu/s fault/wsec 15 16 1 0.67s 233.41s 14.76s 16798.546 266356.260 +-------------------------------------------------------------------------+ N Min Max Median Avg Stddev x 10 16682.962 17344.027 16913.524 16928.812 166.5362 + 10 16695.568 16923.896 16820.604 16824.652 84.816568 No difference proven at 95.0% confidence [akpm@linux-foundation.org: fix build] [hughd@google.com: shmem fix] Signed-off-by: Ying Han <yinghan@google.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2011-05-261-0/+11
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/djm/tmem: xen: cleancache shim to Xen Transcendent Memory ocfs2: add cleancache support ext4: add cleancache support btrfs: add cleancache support ext3: add cleancache support mm/fs: add hooks to support cleancache mm: cleancache core ops functions and config fs: add field to superblock to support cleancache mm/fs: cleancache documentation Fix up trivial conflict in fs/btrfs/extent_io.c due to includes
| * mm/fs: add hooks to support cleancacheDan Magenheimer2011-05-261-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fourth patch of eight in this cleancache series provides the core hooks in VFS for: initializing cleancache per filesystem; capturing clean pages reclaimed by page cache; attempting to get pages from cleancache before filesystem read; and ensuring coherency between pagecache, disk, and cleancache. Note that the placement of these hooks was stable from 2.6.18 to 2.6.38; a minor semantic change was required due to a patchset in 2.6.39. All hooks become no-ops if CONFIG_CLEANCACHE is unset, or become a check of a boolean global if CONFIG_CLEANCACHE is set but no cleancache "backend" has claimed cleancache_ops. Details and a FAQ can be found in Documentation/vm/cleancache.txt [v8: minchan.kim@gmail.com: adapt to new remove_from_page_cache function] Signed-off-by: Chris Mason <chris.mason@oracle.com> Signed-off-by: Dan Magenheimer <dan.magenheimer@oracle.com> Reviewed-by: Jeremy Fitzhardinge <jeremy@goop.org> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik Van Riel <riel@redhat.com> Cc: Jan Beulich <JBeulich@novell.com> Cc: Andreas Dilger <adilger@sun.com> Cc: Ted Ts'o <tytso@mit.edu> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <joel.becker@oracle.com> Cc: Nitin Gupta <ngupta@vflare.org>
* | readahead: trigger mmap sequential readahead on PG_readaheadWu Fengguang2011-05-251-4/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously the mmap sequential readahead is triggered by updating ra->prev_pos on each page fault and compare it with current page offset. It costs dirtying the cache line on each _minor_ page fault. So remove the ra->prev_pos recording, and instead tag PG_readahead to trigger the possible sequential readahead. It's not only more simple, but also will work more reliably and reduce cache line bouncing on concurrent page faults on shared struct file. In the mosbench exim benchmark which does multi-threaded page faults on shared struct file, the ra->mmap_miss and ra->prev_pos updates are found to cause excessive cache line bouncing on tmpfs, which actually disabled readahead totally (shmem_backing_dev_info.ra_pages == 0). So remove the ra->prev_pos recording, and instead tag PG_readahead to trigger the possible sequential readahead. It's not only more simple, but also will work more reliably on concurrent reads on shared struct file. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Tested-by: Tim Chen <tim.c.chen@intel.com> Reported-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | readahead: reduce unnecessary mmap_miss increasesAndi Kleen2011-05-251-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original INT_MAX is too large, reduce it to - avoid unnecessarily dirtying/bouncing the cache line - restore mmap read-around faster on changed access pattern Background: in the mosbench exim benchmark which does multi-threaded page faults on shared struct file, the ra->mmap_miss updates are found to cause excessive cache line bouncing on tmpfs. The ra state updates are needless for tmpfs because it actually disabled readahead totally (shmem_backing_dev_info.ra_pages == 0). Tested-by: Tim Chen <tim.c.chen@intel.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | readahead: return early when readahead is disabledWu Fengguang2011-05-251-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | Reduce readahead overheads by returning early in do_sync_mmap_readahead(). tmpfs has ra_pages=0 and it can page fault really fast (not constraint by IO if not swapping). Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Tested-by: Tim Chen <tim.c.chen@intel.com> Reported-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: Convert i_mmap_lock to a mutexPeter Zijlstra2011-05-251-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Straightforward conversion of i_mmap_lock to a mutex. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Hugh Dickins <hughd@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Jeff Dike <jdike@addtoit.com> Cc: Richard Weinberger <richard@nod.at> Cc: Tony Luck <tony.luck@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | x86,mm: make pagefault killableKOSAKI Motohiro2011-05-251-7/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When an oom killing occurs, almost all processes are getting stuck at the following two points. 1) __alloc_pages_nodemask 2) __lock_page_or_retry 1) is not very problematic because TIF_MEMDIE leads to an allocation failure and getting out from page allocator. 2) is more problematic. In an OOM situation, zones typically don't have page cache at all and memory starvation might lead to greatly reduced IO performance. When a fork bomb occurs, TIF_MEMDIE tasks don't die quickly, meaning that a fork bomb may create new process quickly rather than the oom-killer killing it. Then, the system may become livelocked. This patch makes the pagefault interruptible by SIGKILL. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: introduce wait_on_page_locked_killable()KOSAKI Motohiro2011-05-251-0/+11
|/ | | | | | | | | | | | | | | | commit 2687a356 ("Add lock_page_killable") introduced killable lock_page(). Similarly this patch introdues killable wait_on_page_locked(). Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2011-03-241-4/+6
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6 * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: fs: simplify iget & friends fs: pull inode->i_lock up out of writeback_single_inode fs: rename inode_lock to inode_hash_lock fs: move i_wb_list out from under inode_lock fs: move i_sb_list out from under inode_lock fs: remove inode_lock from iput_final and prune_icache fs: Lock the inode LRU list separately fs: factor inode disposal fs: protect inode->i_state with inode->i_lock autofs4: Do not potentially dereference NULL pointer returned by fget() in autofs_dev_ioctl_setpipefd() autofs4 - remove autofs4_lock autofs4 - fix d_manage() return on rcu-walk autofs4 - fix autofs4_expire_indirect() traversal autofs4 - fix dentry leak in autofs4_expire_direct() autofs4 - reinstate last used update on access vfs - check non-mountpoint dentry might block in __follow_mount_rcu()
| * fs: move i_wb_list out from under inode_lockDave Chinner2011-03-241-4/+4
| | | | | | | | | | | | | | | | | | | | | | Protect the inode writeback list with a new global lock inode_wb_list_lock and use it to protect the list manipulations and traversals. This lock replaces the inode_lock as the inodes on the list can be validity checked while holding the inode->i_lock and hence the inode_lock is no longer needed to protect the list. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
| * fs: protect inode->i_state with inode->i_lockDave Chinner2011-03-241-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Protect inode state transitions and validity checks with the inode->i_lock. This enables us to make inode state transitions independently of the inode_lock and is the first step to peeling away the inode_lock from the code. This requires that __iget() is done atomically with i_state checks during list traversals so that we don't race with another thread marking the inode I_FREEING between the state check and grabbing the reference. Also remove the unlock_new_inode() memory barrier optimisation required to avoid taking the inode_lock when clearing I_NEW. Simplify the code by simply taking the inode->i_lock around the state change and wakeup. Because the wakeup is no longer tricky, remove the wake_up_inode() function and open code the wakeup where necessary. Signed-off-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds2011-03-241-61/+13
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits) Documentation/iostats.txt: bit-size reference etc. cfq-iosched: removing unnecessary think time checking cfq-iosched: Don't clear queue stats when preempt. blk-throttle: Reset group slice when limits are changed blk-cgroup: Only give unaccounted_time under debug cfq-iosched: Don't set active queue in preempt block: fix non-atomic access to genhd inflight structures block: attempt to merge with existing requests on plug flush block: NULL dereference on error path in __blkdev_get() cfq-iosched: Don't update group weights when on service tree fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away block: Require subsystems to explicitly allocate bio_set integrity mempool jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging fs: make fsync_buffers_list() plug mm: make generic_writepages() use plugging blk-cgroup: Add unaccounted time to timeslice_used. block: fixup plugging stubs for !CONFIG_BLOCK block: remove obsolete comments for blkdev_issue_zeroout. blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. ... Fix up conflicts in fs/{aio.c,super.c}
| * fs: make generic file read/write functions plugJens Axboe2011-03-101-0/+7
| | | | | | | | Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
| * block: remove per-queue pluggingJens Axboe2011-03-101-61/+6
| | | | | | | | | | | | | | | | Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | mm: don't return 0 too early from find_get_pages()Hugh Dickins2011-03-221-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Callers of find_get_pages(), or its wrapper pagevec_lookup() - notably truncate_inode_pages_range() - stop looking further when it returns 0. But if an interrupt comes just after its radix_tree_gang_lookup_slot(), especially if we have preemptible RCU enabled, isn't it conceivable that all 14 pages returned could be removed from the page cache by shrink_page_list(), before find_get_pages() gets to process them? So causing it to return 0 although there may be plenty more pages beyond. Make find_get_pages() and find_get_pages_tag() check for this unlikely case, and restart should it occur; but callers of find_get_pages_contig() have no such expectation, it's okay for that to return 0 early. I have not seen this in practice, just worried by the possibility. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Nick Piggin <npiggin@kernel.dk> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Salman Qazi <sqazi@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: remove worrying dead code from find_get_pages()Hugh Dickins2011-03-221-2/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The radix_tree_deref_retry() case in find_get_pages() has a strange little excrescence, not seen in the other gang lookups: it looks like the start of an abandoned attempt to guarantee forward progress in a case that cannot arise. ret should always be 0 here: if it isn't, then going back to restart will leak references to pages already gotten. There used to be a comment saying nr_found is necessarily 1 here: that's not quite true, but the radix_tree_deref_retry() case is peculiar to the entry at index 0, when we race with it being moved out of the radix_tree root or back. Remove the worrisome two lines, add a brief comment here and in find_get_pages_contig() and find_get_pages_tag(), and a WARN_ON in find_get_pages() should it ever be seen elsewhere than at 0. Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Nick Piggin <npiggin@kernel.dk> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Salman Qazi <sqazi@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: change __remove_from_page_cache()Minchan Kim2011-03-221-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now we renamed remove_from_page_cache with delete_from_page_cache. As consistency of __remove_from_swap_cache and remove_from_swap_cache, we change internal page cache handling function name, too. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: goodbye remove_from_page_cache()Minchan Kim2011-03-221-16/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now delete_from_page_cache() replaces remove_from_page_cache(). So we remove remove_from_page_cache so fs or something out of mainline will notice it when compile time and can fix it. Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: introduce delete_from_page_cache()Minchan Kim2011-03-221-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Presently we increase the page refcount in add_to_page_cache() but don't decrease it in remove_from_page_cache(). Such asymmetry adds confusion, requiring that callers notice it and a comment explaining why they release a page reference. It's not a good API. A long time ago, Hugh tried it (http://lkml.org/lkml/2004/10/24/140) but gave up because reiser4's drop_page() had to unlock the page between removing it from page cache and doing the page_cache_release(). But now the situation is changed. I think at least things in current mainline don't have any obstacles. The problem is for out-of-mainline filesystems - if they have done such things as reiser4, this patch could be a problem but they will discover this at compile time since we remove remove_from_page_cache(). This patch: This function works as just wrapper remove_from_page_cache(). The difference is that it decreases page references in itself. So caller have to make sure it has a page reference before calling. This patch is ready for removing remove_from_page_cache(). Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Acked-by: Hugh Dickins <hughd@google.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Edward Shishkin <edward.shishkin@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: add replace_page_cache_page() functionMiklos Szeredi2011-03-221-0/+70
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This function basically does: remove_from_page_cache(old); page_cache_release(old); add_to_page_cache_locked(new); Except it does this atomically, so there's no possibility for the "add" to fail because of a race. If memory cgroups are enabled, then the memory cgroup charge is also moved from the old page to the new. This function is currently used by fuse to move pages into the page cache on read, instead of copying the page contents. [minchan.kim@gmail.com: add freepage() hook to replace_page_cache_page()] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: allow GUP to fail instead of waiting on a pageGleb Natapov2011-03-221-2/+4
|/ | | | | | | | | | | | | | | | | | | | | | | | | GUP user may want to try to acquire a reference to a page if it is already in memory, but not if IO, to bring it in, is needed. For example KVM may tell vcpu to schedule another guest process if current one is trying to access swapped out page. Meanwhile, the page will be swapped in and the guest process, that depends on it, will be able to run again. This patch adds FAULT_FLAG_RETRY_NOWAIT (suggested by Linus) and FOLL_NOWAIT follow_page flags. FAULT_FLAG_RETRY_NOWAIT, when used in conjunction with VM_FAULT_ALLOW_RETRY, indicates to handle_mm_fault that it shouldn't drop mmap_sem and wait on a page, but return VM_FAULT_RETRY instead. [akpm@linux-foundation.org: improve FOLL_NOWAIT comment] Signed-off-by: Gleb Natapov <gleb@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Michel Lespinasse <walken@google.com> Cc: Avi Kivity <avi@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove likely() from grab_cache_page_write_begin()Steven Rostedt2011-01-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Running the annotated branch profiler on a box doing average work (firefox, evolution, xchat, distcc farm), the likely() used in grab_cache_page_write_begin() was incorrect most of the time: correct incorrect % Function File Line ------- --------- - -------- ---- ---- 1924262 71332401 97 grab_cache_page_write_begin filemap.c 2206 Adding a trace_printk() and running the function tracer limited to just this function I can see: gconfd-2-2696 [000] 4467.268935: grab_cache_page_write_begin: page= (null) mapping=ffff8800676a9460 index=7 gconfd-2-2696 [000] 4467.268946: grab_cache_page_write_begin <-ext3_write_begin gconfd-2-2696 [000] 4467.268947: grab_cache_page_write_begin: page= (null) mapping=ffff8800676a9460 index=8 gconfd-2-2696 [000] 4467.268959: grab_cache_page_write_begin <-ext3_write_begin gconfd-2-2696 [000] 4467.268960: grab_cache_page_write_begin: page= (null) mapping=ffff8800676a9460 index=9 gconfd-2-2696 [000] 4467.268972: grab_cache_page_write_begin <-ext3_write_begin gconfd-2-2696 [000] 4467.268973: grab_cache_page_write_begin: page= (null) mapping=ffff8800676a9460 index=10 gconfd-2-2696 [000] 4467.268991: grab_cache_page_write_begin <-ext3_write_begin gconfd-2-2696 [000] 4467.268992: grab_cache_page_write_begin: page= (null) mapping=ffff8800676a9460 index=11 gconfd-2-2696 [000] 4467.269005: grab_cache_page_write_begin <-ext3_write_begin Which shows that a lot of calls from ext3_write_begin will result in the page returned by "find_lock_page" will be NULL. Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: clear PageError bit in msync & fsyncRik van Riel2011-01-131-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Temporary IO failures, eg. due to loss of both multipath paths, can permanently leave the PageError bit set on a page, resulting in msync or fsync returning -EIO over and over again, even if IO is now getting to the disk correctly. We already clear the AS_ENOSPC and AS_IO bits in mapping->flags in the filemap_fdatawait_range function. Also clearing the PageError bit on the page allows subsequent msync or fsync calls on this file to return without an error, if the subsequent IO succeeds. Unfortunately data written out in the msync or fsync call that returned -EIO can still get lost, because the page dirty bit appears to not get restored on IO error. However, the alternative could be potentially all of memory filling up with uncleanable dirty pages, hanging the system, so there is no nice choice here... Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Valerie Aurora <vaurora@redhat.com> Acked-by: Jeff Layton <jlayton@redhat.com> Cc: Theodore Ts'o <tytso@mit.edu> Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: find_get_pages_contig fixletNick Piggin2011-01-131-3/+10
| | | | | | | | | | | Testing ->mapping and ->index without a ref is not stable as the page may have been reused at this point. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: dcache remove dcache_lockNick Piggin2011-01-071-3/+0
| | | | | | dcache_lock no longer protects anything. remove it. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
* Call the filesystem back whenever a page is removed from the page cacheLinus Torvalds2010-12-021-0/+5
| | | | | | | | | | | | | | NFS needs to be able to release objects that are stored in the page cache once the page itself is no longer visible from the page cache. This patch adds a callback to the address space operations that allows filesystems to perform page cleanups once the page has been removed from the page cache. Original patch by: Linus Torvalds <torvalds@linux-foundation.org> [trondmy: cover the cases of invalidate_inode_pages2() and truncate_inode_pages()] Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
* radix-tree: fix RCU bugNick Piggin2010-11-121-16/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Salman Qazi describes the following radix-tree bug: In the following case, we get can get a deadlock: 0. The radix tree contains two items, one has the index 0. 1. The reader (in this case find_get_pages) takes the rcu_read_lock. 2. The reader acquires slot(s) for item(s) including the index 0 item. 3. The non-zero index item is deleted, and as a consequence the other item is moved to the root of the tree. The place where it used to be is queued for deletion after the readers finish. 3b. The zero item is deleted, removing it from the direct slot, it remains in the rcu-delayed indirect node. 4. The reader looks at the index 0 slot, and finds that the page has 0 ref count 5. The reader looks at it again, hoping that the item will either be freed or the ref count will increase. This never happens, as the slot it is looking at will never be updated. Also, this slot can never be reclaimed because the reader is holding rcu_read_lock and is in an infinite loop. The fix is to re-use the same "indirect" pointer case that requires a slot lookup retry into a general "retry the lookup" bit. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Reported-by: Salman Qazi <sqazi@google.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/vfs: revalidate page->mapping in do_generic_file_read()Dave Hansen2010-11-121-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 70 hours into some stress tests of a 2.6.32-based enterprise kernel, we ran into a NULL dereference in here: int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc, unsigned long from) { ----> struct inode *inode = page->mapping->host; It looks like page->mapping was the culprit. (xmon trace is below). After closer examination, I realized that do_generic_file_read() does a find_get_page(), and eventually locks the page before calling block_is_partially_uptodate(). However, it doesn't revalidate the page->mapping after the page is locked. So, there's a small window between the find_get_page() and ->is_partially_uptodate() where the page could get truncated and page->mapping cleared. We _have_ a reference, so it can't get reclaimed, but it certainly can be truncated. I think the correct thing is to check page->mapping after the trylock_page(), and jump out if it got truncated. This patch has been running in the test environment for a month or so now, and we have not seen this bug pop up again. xmon info: 1f:mon> e cpu 0x1f: Vector: 300 (Data Access) at [c0000002ae36f770] pc: c0000000001e7a6c: .block_is_partially_uptodate+0xc/0x100 lr: c000000000142944: .generic_file_aio_read+0x1e4/0x770 sp: c0000002ae36f9f0 msr: 8000000000009032 dar: 0 dsisr: 40000000 current = 0xc000000378f99e30 paca = 0xc000000000f66300 pid = 21946, comm = bash 1f:mon> r R00 = 0025c0500000006d R16 = 0000000000000000 R01 = c0000002ae36f9f0 R17 = c000000362cd3af0 R02 = c000000000e8cd80 R18 = ffffffffffffffff R03 = c0000000031d0f88 R19 = 0000000000000001 R04 = c0000002ae36fa68 R20 = c0000003bb97b8a0 R05 = 0000000000000000 R21 = c0000002ae36fa68 R06 = 0000000000000000 R22 = 0000000000000000 R07 = 0000000000000001 R23 = c0000002ae36fbb0 R08 = 0000000000000002 R24 = 0000000000000000 R09 = 0000000000000000 R25 = c000000362cd3a80 R10 = 0000000000000000 R26 = 0000000000000002 R11 = c0000000001e7b60 R27 = 0000000000000000 R12 = 0000000042000484 R28 = 0000000000000001 R13 = c000000000f66300 R29 = c0000003bb97b9b8 R14 = 0000000000000001 R30 = c000000000e28a08 R15 = 000000000000ffff R31 = c0000000031d0f88 pc = c0000000001e7a6c .block_is_partially_uptodate+0xc/0x100 lr = c000000000142944 .generic_file_aio_read+0x1e4/0x770 msr = 8000000000009032 cr = 22000488 ctr = c0000000001e7a60 xer = 0000000020000000 trap = 300 dar = 0000000000000000 dsisr = 40000000 1f:mon> t [link register ] c000000000142944 .generic_file_aio_read+0x1e4/0x770 [c0000002ae36f9f0] c000000000142a14 .generic_file_aio_read+0x2b4/0x770 (unreliable) [c0000002ae36fb40] c0000000001b03e4 .do_sync_read+0xd4/0x160 [c0000002ae36fce0] c0000000001b153c .vfs_read+0xec/0x1f0 [c0000002ae36fd80] c0000000001b1768 .SyS_read+0x58/0xb0 [c0000002ae36fe30] c00000000000852c syscall_exit+0x0/0x40 --- Exception: c00 (System Call) at 00000080a840bc54 SP (fffca15df30) is in userspace 1f:mon> di c0000000001e7a6c c0000000001e7a6c e9290000 ld r9,0(r9) c0000000001e7a70 418200c0 beq c0000000001e7b30 # .block_is_partially_uptodate+0xd0/0x100 c0000000001e7a74 e9440008 ld r10,8(r4) c0000000001e7a78 78a80020 clrldi r8,r5,32 c0000000001e7a7c 3c000001 lis r0,1 c0000000001e7a80 812900a8 lwz r9,168(r9) c0000000001e7a84 39600001 li r11,1 c0000000001e7a88 7c080050 subf r0,r8,r0 c0000000001e7a8c 7f805040 cmplw cr7,r0,r10 c0000000001e7a90 7d6b4830 slw r11,r11,r9 c0000000001e7a94 796b0020 clrldi r11,r11,32 c0000000001e7a98 419d00a8 bgt cr7,c0000000001e7b40 # .block_is_partially_uptodate+0xe0/0x100 c0000000001e7a9c 7fa55840 cmpld cr7,r5,r11 c0000000001e7aa0 7d004214 add r8,r0,r8 c0000000001e7aa4 79080020 clrldi r8,r8,32 c0000000001e7aa8 419c0078 blt cr7,c0000000001e7b20 # .block_is_partially_uptodate+0xc0/0x100 Signed-off-by: Dave Hansen <dave@linux.vnet.ibm.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: <arunabal@in.ibm.com> Cc: <sbest@us.ibm.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Release page reference during page fault retryMichel Lespinasse2010-11-021-1/+3
| | | | | | | | | This slipped by when unifying the filemap and swap versions of lock_page_or_retry()... Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove temporary variable on generic_file_direct_write()Namhyung Kim2010-10-261-4/+4
| | | | | | | | | | | | 'end' shadows earlier one and is not necessary at all. Remove it and use 'pos' instead. This removes following sparse warnings: mm/filemap.c:2180:24: warning: symbol 'end' shadows an earlier one mm/filemap.c:2132:25: originally declared here Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: retry page fault when blocking on disk transferMichel Lespinasse2010-10-261-1/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change reduces mmap_sem hold times that are caused by waiting for disk transfers when accessing file mapped VMAs. It introduces the VM_FAULT_ALLOW_RETRY flag, which indicates that the call site wants mmap_sem to be released if blocking on a pending disk transfer. In that case, filemap_fault() returns the VM_FAULT_RETRY status bit and do_page_fault() will then re-acquire mmap_sem and retry the page fault. It is expected that the retry will hit the same page which will now be cached, and thus it will complete with a low mmap_sem hold time. Tests: - microbenchmark: thread A mmaps a large file and does random read accesses to the mmaped area - achieves about 55 iterations/s. Thread B does mmap/munmap in a loop at a separate location - achieves 55 iterations/s before, 15000 iterations/s after. - We are seeing related effects in some applications in house, which show significant performance regressions when running without this change. [akpm@linux-foundation.org: fix warning & crash] Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Ying Han <yinghan@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: filemap_fault: unique path for locking pageMichel Lespinasse2010-10-261-9/+11
| | | | | | | | | | | | | | | | | | | | Introduce a single location where filemap_fault() locks the desired page. There used to be two such places, depending if the initial find_get_page() was successful or not. Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Ying Han <yinghan@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* gcc-4.6: mm: fix unused but set warningsAndi Kleen2010-08-091-2/+0
| | | | | | | | No real bugs, just some dead code and some fixups. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2010-05-301-0/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/fuse: mm: export generic_pipe_buf_*() to modules fuse: support splice() reading from fuse device fuse: allow splice to move pages mm: export remove_from_page_cache() to modules mm: export lru_cache_add_*() to modules fuse: support splice() writing to fuse device fuse: get page reference for readpages fuse: use get_user_pages_fast() fuse: remove unneeded variable
| * mm: export remove_from_page_cache() to modulesMiklos Szeredi2010-05-251-0/+1
| | | | | | | | | | | | | | This is needed to enable moving pages into the page cache in fuse with splice(..., SPLICE_F_MOVE). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstableLinus Torvalds2010-05-271-5/+31
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (27 commits) Btrfs: add more error checking to btrfs_dirty_inode Btrfs: allow unaligned DIO Btrfs: drop verbose enospc printk Btrfs: Fix block generation verification race Btrfs: fix preallocation and nodatacow checks in O_DIRECT Btrfs: avoid ENOSPC errors in btrfs_dirty_inode Btrfs: move O_DIRECT space reservation to btrfs_direct_IO Btrfs: rework O_DIRECT enospc handling Btrfs: use async helpers for DIO write checksumming Btrfs: don't walk around with task->state != TASK_RUNNING Btrfs: do aio_write instead of write Btrfs: add basic DIO read/write support direct-io: do not merge logically non-contiguous requests direct-io: add a hook for the fs to provide its own submit_bio function fs: allow short direct-io reads to be completed via buffered IO Btrfs: Metadata ENOSPC handling for balance Btrfs: Pre-allocate space for data relocation Btrfs: Metadata ENOSPC handling for tree log Btrfs: Metadata reservation for orphan inodes Btrfs: Introduce global metadata reservation ...
| * | fs: allow short direct-io reads to be completed via buffered IOJosef Bacik2010-05-251-5/+31
| |/ | | | | | | | | | | | | | | | | | | | | | | | | This is similar to what already happens in the write case. If we have a short read while doing O_DIRECT, instead of just returning, fallthrough and try to read the rest via buffered IO. BTRFS needs this because if we encounter a compressed or inline extent during DIO, we need to fallback on buffered. If the extent is compressed we need to read the entire thing into memory and de-compress it into the users pages. I have tested this with fsx and everything works great. Thanks, Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Chris Mason <chris.mason@oracle.com>
* | do_generic_file_read: clear page errors when issuing a fresh read of the pageJeff Moyer2010-05-261-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I/O errors can happen due to temporary failures, like multipath errors or losing network contact with the iSCSI server. Because of that, the VM will retry readpage on the page. However, do_generic_file_read does not clear PG_error. This causes the system to be unable to actually use the data in the page cache page, even if the subsequent readpage completes successfully! The function filemap_fault has had a ClearPageError before readpage forever. This patch simply adds the same to do_generic_file_read. Signed-off-by: Jeff Moyer <jmoyer@redhat.com> Signed-off-by: Rik van Riel <riel@redhat.com> Acked-by: Larry Woodman <lwoodman@redhat.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | cpuset,mm: fix no node to alloc memory when changing cpuset's memsMiao Xie2010-05-251-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before applying this patch, cpuset updates task->mems_allowed and mempolicy by setting all new bits in the nodemask first, and clearing all old unallowed bits later. But in the way, the allocator may find that there is no node to alloc memory. The reason is that cpuset rebinds the task's mempolicy, it cleans the nodes which the allocater can alloc pages on, for example: (mpol: mempolicy) task1 task1's mpol task2 alloc page 1 alloc on node0? NO 1 1 change mems from 1 to 0 1 rebind task1's mpol 0-1 set new bits 0 clear disallowed bits alloc on node1? NO 0 ... can't alloc page goto oom This patch fixes this problem by expanding the nodes range first(set newly allowed bits) and shrink it lazily(clear newly disallowed bits). So we use a variable to tell the write-side task that read-side task is reading nodemask, and the write-side task clears newly disallowed nodes after read-side task ends the current memory allocation. [akpm@linux-foundation.org: fix spello] Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Paul Menage <menage@google.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Ravikiran Thirumalai <kiran@scalex86.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Andi Kleen <andi@firstfloor.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | tmpfs: insert tmpfs cache pages to inactive list at firstKOSAKI Motohiro2010-05-251-2/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Shaohua Li reported parallel file copy on tmpfs can lead to OOM killer. This is regression of caused by commit 9ff473b9a7 ("vmscan: evict streaming IO first"). Wow, It is 2 years old patch! Currently, tmpfs file cache is inserted active list at first. This means that the insertion doesn't only increase numbers of pages in anon LRU, but it also reduces anon scanning ratio. Therefore, vmscan will get totally confused. It scans almost only file LRU even though the system has plenty unused tmpfs pages. Historically, lru_cache_add_active_anon() was used for two reasons. 1) Intend to priotize shmem page rather than regular file cache. 2) Intend to avoid reclaim priority inversion of used once pages. But we've lost both motivation because (1) Now we have separate anon and file LRU list. then, to insert active list doesn't help such priotize. (2) In past, one pte access bit will cause page activation. then to insert inactive list with pte access bit mean higher priority than to insert active list. Its priority inversion may lead to uninteded lru chun. but it was already solved by commit 645747462 (vmscan: detect mapped file pages used only once). (Thanks Hannes, you are great!) Thus, now we can use lru_cache_add_anon() instead. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reported-by: Shaohua Li <shaohua.li@intel.com> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo2010-03-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
* mm: use rlimit helpersJiri Slaby2010-03-061-1/+1
| | | | | | | | | | | | | 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 <jslaby@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kill unused invalidate_inode_pages helperChristoph Hellwig2010-03-031-1/+1
| | | | | | | | | | | 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 <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mm: flush dcache before writing into page to avoid aliasanfei zhou2010-02-021-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <anfei.zhou@gmail.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Miklos Szeredi <miklos@szeredi.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: <linux-arch@vger.kernel.org> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: add new 'read_cache_page_gfp()' helper functionLinus Torvalds2010-01-271-32/+68
| | | | | | | | | | | | | | | | | | | | 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 <chris@chris-wilson.co.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* direct I/O fallback sync simplificationChristoph Hellwig2009-12-161-14/+1
| | | | | | | | | | | | | | 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 <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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