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* vmscan: split LRU lists into anon & file setsRik van Riel2008-10-201-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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. [lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset] [kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru] [kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page] [hugh@veritas.com: memcg swapbacked pages active] [hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED] [akpm@linux-foundation.org: fix /proc/vmstat units] [nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration] [kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo] [kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs: Add no_nrwrite_index_update writeback control flagAneesh Kumar K.V2008-10-161-3/+7
| | | | | | | | | | | | If no_nrwrite_index_update is set we don't update nr_to_write and address space writeback_index in write_cache_pages. This change enables a file system to skip these updates in write_cache_pages and do them in the writepages() callback. This patch will be followed by an ext4 patch that make use of these new flags. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> CC: linux-fsdevel@vger.kernel.org
* vfs: Remove the range_cont writeback mode.Aneesh Kumar K.V2008-10-141-2/+0
| | | | | | | | | | Ext4 was the only user of range_cont writeback mode and ext4 switched to a different method. So remove the range_cont mode which is not used in the kernel. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> CC: linux-fsdevel@vger.kernel.org
* Remove Andrew Morton's old email accountsFrancois Cami2008-10-161-1/+1
| | | | | | | | | People can use the real name an an index into MAINTAINERS to find the current email address. Signed-off-by: Francois Cami <francois.cami@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: spinlock tree_lockNick Piggin2008-07-261-6/+6
| | | | | | | | | | | | | | mapping->tree_lock has no read lockers. convert the lock from an rwlock to a spinlock. Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Hugh Dickins <hugh@veritas.com> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for_linus' of ↵Linus Torvalds2008-07-151-0/+3
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 * 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (61 commits) ext4: Documention update for new ordered mode and delayed allocation ext4: do not set extents feature from the kernel ext4: Don't allow nonextenst mount option for large filesystem ext4: Enable delalloc by default. ext4: delayed allocation i_blocks fix for stat ext4: fix delalloc i_disksize early update issue ext4: Handle page without buffers in ext4_*_writepage() ext4: Add ordered mode support for delalloc ext4: Invert lock ordering of page_lock and transaction start in delalloc mm: Add range_cont mode for writeback ext4: delayed allocation ENOSPC handling percpu_counter: new function percpu_counter_sum_and_set ext4: Add delayed allocation support in data=writeback mode vfs: add hooks for ext4's delayed allocation support jbd2: Remove data=ordered mode support using jbd buffer heads ext4: Use new framework for data=ordered mode in JBD2 jbd2: Implement data=ordered mode handling via inodes vfs: export filemap_fdatawrite_range() ext4: Fix lock inversion in ext4_ext_truncate() ext4: Invert the locking order of page_lock and transaction start ...
| * mm: Add range_cont mode for writebackAneesh Kumar K.V2008-07-121-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Filesystems like ext4 needs to start a new transaction in the writepages for block allocation. This happens with delayed allocation and there is limit to how many credits we can request from the journal layer. So we call write_cache_pages multiple times with wbc->nr_to_write set to the maximum possible value limitted by the max journal credits available. Add a new mode to writeback that enables us to handle this behaviour. In the new mode we update the wbc->range_start to point to the new offset to be written. Next call to call to write_cache_pages will start writeout from specified range_start offset. In the new mode we also limit writing to the specified wbc->range_end. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
* | ftrace: limit trace entriesSteven Rostedt2008-05-231-3/+7
|/ | | | | | | | | | | | | | | | | | | | | | Currently there is no protection from the root user to use up all of memory for trace buffers. If the root user allocates too many entries, the OOM killer might start kill off all tasks. This patch adds an algorith to check the following condition: pages_requested > (freeable_memory + current_trace_buffer_pages) / 4 If the above is met then the allocation fails. The above prevents more than 1/4th of freeable memory from being used by trace buffers. To determine the freeable_memory, I made determine_dirtyable_memory in mm/page-writeback.c global. Special thanks goes to Peter Zijlstra for suggesting the above calculation. Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* mm: Add NR_WRITEBACK_TEMP counterMiklos Szeredi2008-04-301-1/+2
| | | | | | | | | | | | | | | | | | | | Fuse will use temporary buffers to write back dirty data from memory mappings (normal writes are done synchronously). This is needed, because there cannot be any guarantee about the time in which a write will complete. By using temporary buffers, from the MM's point if view the page is written back immediately. If the writeout was due to memory pressure, this effectively migrates data from a full zone to a less full zone. This patch adds a new counter (NR_WRITEBACK_TEMP) for the number of pages used as temporary buffers. [Lee.Schermerhorn@hp.com: add vmstat_text for NR_WRITEBACK_TEMP] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: bdi: export bdi_writeout_inc()Miklos Szeredi2008-04-301-0/+10
| | | | | | | | | Fuse needs this for writable mmap support. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: bdi: add separate writeback accounting capabilityMiklos Szeredi2008-04-301-2/+2
| | | | | | | | | | | | | | | | | Add a new BDI capability flag: BDI_CAP_NO_ACCT_WB. If this flag is set, then don't update the per-bdi writeback stats from test_set_page_writeback() and test_clear_page_writeback(). Misc cleanups: - convert bdi_cap_writeback_dirty() and friends to static inline functions - create a flag that includes all three dirty/writeback related flags, since almst all users will want to have them toghether Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: bdi: allow setting a maximum for the bdi dirty limitPeter Zijlstra2008-04-301-6/+35
| | | | | | | | | | | | | | | | | Add "max_ratio" to /sys/class/bdi. This indicates the maximum percentage of the global dirty threshold allocated to this bdi. [mszeredi@suse.cz] - fix parsing in max_ratio_store(). - export bdi_set_max_ratio() to modules - limit bdi_dirty with bdi->max_ratio - document new sysfs attribute Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: bdi: allow setting a minimum for the bdi dirty limitPeter Zijlstra2008-04-301-1/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Under normal circumstances each device is given a part of the total write-back cache that relates to its current avg writeout speed in relation to the other devices. min_ratio - allows one to assign a minimum portion of the write-back cache to a particular device. This is useful in situations where you might want to provide a minimum QoS. (One request for this feature came from flash based storage people who wanted to avoid writing out at all costs - they of course needed some pdflush hacks as well) max_ratio - allows one to assign a maximum portion of the dirty limit to a particular device. This is useful in situations where you want to avoid one device taking all or most of the write-back cache. Eg. an NFS mount that is prone to get stuck, or a FUSE mount which you don't trust to play fair. Add "min_ratio" to /sys/class/bdi. This indicates the minimum percentage of the global dirty threshold allocated to this bdi. [mszeredi@suse.cz] - fix parsing in min_ratio_store() - document new sysfs attribute Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: bdi: export BDI attributes in sysfsPeter Zijlstra2008-04-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Provide a place in sysfs (/sys/class/bdi) for the backing_dev_info object. This allows us to see and set the various BDI specific variables. In particular this properly exposes the read-ahead window for all relevant users and /sys/block/<block>/queue/read_ahead_kb should be deprecated. With patient help from Kay Sievers and Greg KH [mszeredi@suse.cz] - split off NFS and FUSE changes into separate patches - document new sysfs attributes under Documentation/ABI - do bdi_class_init as a core_initcall, otherwise the "default" BDI won't be initialized - remove bdi_init_fmt macro, it's not used very much [akpm@linux-foundation.org: fix ia64 warning] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Greg KH <greg@kroah.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* writeback: speed up writeback of big dirty filesFengguang Wu2008-02-051-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After making dirty a 100M file, the normal behavior is to start the writeback for all data after 30s delays. But sometimes the following happens instead: - after 30s: ~4M - after 5s: ~4M - after 5s: all remaining 92M Some analyze shows that the internal io dispatch queues goes like this: s_io s_more_io ------------------------- 1) 100M,1K 0 2) 1K 96M 3) 0 96M 1) initial state with a 100M file and a 1K file 2) 4M written, nr_to_write <= 0, so write more 3) 1K written, nr_to_write > 0, no more writes(BUG) nr_to_write > 0 in (3) fools the upper layer to think that data have all been written out. The big dirty file is actually still sitting in s_more_io. We cannot simply splice s_more_io back to s_io as soon as s_io becomes empty, and let the loop in generic_sync_sb_inodes() continue: this may starve newly expired inodes in s_dirty. It is also not an option to draw inodes from both s_more_io and s_dirty, an let the loop go on: this might lead to live locks, and might also starve other superblocks in sync time(well kupdate may still starve some superblocks, that's another bug). We have to return when a full scan of s_io completes. So nr_to_write > 0 does not necessarily mean that "all data are written". This patch introduces a flag writeback_control.more_io to indicate that more io should be done. With it the big dirty file no longer has to wait for the next kupdate invokation 5s later. In sync_sb_inodes() we only set more_io on super_blocks we actually visited. This avoids the interaction between two pdflush deamons. Also in __sync_single_inode() we don't blindly keep requeuing the io if the filesystem cannot progress. Failing to do so may lead to 100% iowait. Tested-by: Mike Snitzer <snitzer@gmail.com> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Michael Rubin <mrubin@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove fastcall from mm/Harvey Harrison2008-02-051-1/+1
| | | | | | | | | fastcall is always defined to be empty, remove it [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page-writeback: highmem_is_dirtyable optionBron Gondwana2008-02-051-1/+10
| | | | | | | | | | | | | | | | | | | | | Add vm.highmem_is_dirtyable toggle A 32 bit machine with HIGHMEM64 enabled running DCC has an MMAPed file of approximately 2Gb size which contains a hash format that is written randomly by the dbclean process. On 2.6.16 this process took a few minutes. With lowmem only accounting of dirty ratios, this takes about 12 hours of 100% disk IO, all random writes. Include a toggle in /proc/sys/vm/highmem_is_dirtyable which can be set to 1 to add the highmem back to the total available memory count. [akpm@linux-foundation.org: Fix the CONFIG_DETECT_SOFTLOCKUP=y build] Signed-off-by: Bron Gondwana <brong@fastmail.fm> Cc: Ethan Solomita <solo@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm/page-writeback.c: make a function staticAdrian Bunk2008-02-051-1/+1
| | | | | | | | task_dirty_limit() can become static. Signed-off-by: Adrian Bunk <bunk@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Revert "writeback: introduce writeback_control.more_io to indicate more io"Linus Torvalds2008-01-151-6/+3
| | | | | | | | | | | | | | | | | | | This reverts commit 2e6883bdf49abd0e7f0d9b6297fc3be7ebb2250b, as requested by Fengguang Wu. It's not quite fully baked yet, and while there are patches around to fix the problems it caused, they should get more testing. Says Fengguang: "I'll resend them both for -mm later on, in a more complete patchset". See http://bugzilla.kernel.org/show_bug.cgi?id=9738 for some of this discussion. Requested-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dirty page balancing: Get rid of broken unmapped_ratio logicLinus Torvalds2007-11-161-8/+0
| | | | | | | | | | | | | | | | | | | | This code harks back to the days when we didn't count dirty mapped pages, which led us to try to balance the number of dirty unmapped pages by how much unmapped memory there was in the system. That makes no sense any more, since now the dirty counts include the mapped pages. Not to mention that the math doesn't work with HIGHMEM machines anyway, and causes the unmapped_ratio to potentially turn negative (which we do catch thanks to clamping it at a minimum value, but I mention that as an indication of how broken the code is). The code also was written at a time when the default dirty ratio was much larger, and the unmapped_ratio logic effectively capped that large dirty ratio a bit. Again, we've since lowered the dirty ratio rather aggressively, further lessening the point of that code. Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: speed up writeback ramp-up on clean systemsPeter Zijlstra2007-11-151-2/+17
| | | | | | | | | | | | We allow violation of bdi limits if there is a lot of room on the system. Once we hit half the total limit we start enforcing bdi limits and bdi ramp-up should happen. Doing it this way avoids many small writeouts on an otherwise idle system and should also speed up the ramp-up. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* spelling fixes: mm/Simon Arlott2007-10-201-1/+1
| | | | | | | Spelling fixes in mm/. Signed-off-by: Simon Arlott <simon@fire.lp0.eu> Signed-off-by: Adrian Bunk <bunk@kernel.org>
* writeback: remove unnecessary wait in throttle_vm_writeout()Fengguang Wu2007-10-171-10/+8
| | | | | | | | | | | | | | | We don't want to introduce pointless delays in throttle_vm_writeout() when the writeback limits are not yet exceeded, do we? Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: Greg KH <greg@kroah.com> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* introduce I_SYNCJoern Engel2007-10-171-1/+1
| | | | | | | | | | | | | | | | | | | | I_LOCK was used for several unrelated purposes, which caused deadlock situations in certain filesystems as a side effect. One of the purposes now uses the new I_SYNC bit. Also document the various bits and change their order from historical to logical. [bunk@stusta.de: make fs/inode.c:wake_up_inode() static] Signed-off-by: Joern Engel <joern@wohnheim.fh-wedel.de> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Cc: David Chinner <dgc@sgi.com> Cc: Anton Altaparmakov <aia21@cam.ac.uk> Cc: Al Viro <viro@ftp.linux.org.uk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* writeback: introduce writeback_control.more_io to indicate more ioFengguang Wu2007-10-171-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | After making dirty a 100M file, the normal behavior is to start the writeback for all data after 30s delays. But sometimes the following happens instead: - after 30s: ~4M - after 5s: ~4M - after 5s: all remaining 92M Some analyze shows that the internal io dispatch queues goes like this: s_io s_more_io ------------------------- 1) 100M,1K 0 2) 1K 96M 3) 0 96M 1) initial state with a 100M file and a 1K file 2) 4M written, nr_to_write <= 0, so write more 3) 1K written, nr_to_write > 0, no more writes(BUG) nr_to_write > 0 in (3) fools the upper layer to think that data have all been written out. The big dirty file is actually still sitting in s_more_io. We cannot simply splice s_more_io back to s_io as soon as s_io becomes empty, and let the loop in generic_sync_sb_inodes() continue: this may starve newly expired inodes in s_dirty. It is also not an option to draw inodes from both s_more_io and s_dirty, an let the loop go on: this might lead to live locks, and might also starve other superblocks in sync time(well kupdate may still starve some superblocks, that's another bug). We have to return when a full scan of s_io completes. So nr_to_write > 0 does not necessarily mean that "all data are written". This patch introduces a flag writeback_control.more_io to indicate this situation. With it the big dirty file no longer has to wait for the next kupdate invocation 5s later. Cc: David Chinner <dgc@sgi.com> Cc: Ken Chen <kenchen@google.com> Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* writeback: don't propagate AOP_WRITEPAGE_ACTIVATEAndrew Morton2007-10-171-1/+3
| | | | | | | | | This is a writeback-internal marker but we're propagating it all the way back to userspace!. Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: dirty balancing for tasksPeter Zijlstra2007-10-171-1/+49
| | | | | | | | | | | | | | | | | | | | Based on ideas of Andrew: http://marc.info/?l=linux-kernel&m=102912915020543&w=2 Scale the bdi dirty limit inversly with the tasks dirty rate. This makes heavy writers have a lower dirty limit than the occasional writer. Andrea proposed something similar: http://lwn.net/Articles/152277/ The main disadvantage to his patch is that he uses an unrelated quantity to measure time, which leaves him with a workload dependant tunable. Other than that the two approaches appear quite similar. [akpm@linux-foundation.org: fix warning] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: per device dirty thresholdPeter Zijlstra2007-10-171-32/+171
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Scale writeback cache per backing device, proportional to its writeout speed. By decoupling the BDI dirty thresholds a number of problems we currently have will go away, namely: - mutual interference starvation (for any number of BDIs); - deadlocks with stacked BDIs (loop, FUSE and local NFS mounts). It might be that all dirty pages are for a single BDI while other BDIs are idling. By giving each BDI a 'fair' share of the dirty limit, each one can have dirty pages outstanding and make progress. A global threshold also creates a deadlock for stacked BDIs; when A writes to B, and A generates enough dirty pages to get throttled, B will never start writeback until the dirty pages go away. Again, by giving each BDI its own 'independent' dirty limit, this problem is avoided. So the problem is to determine how to distribute the total dirty limit across the BDIs fairly and efficiently. A DBI that has a large dirty limit but does not have any dirty pages outstanding is a waste. What is done is to keep a floating proportion between the DBIs based on writeback completions. This way faster/more active devices get a larger share than slower/idle devices. [akpm@linux-foundation.org: fix warnings] [hugh@veritas.com: Fix occasional hang when a task couldn't get out of balance_dirty_pages] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: count writeback pages per BDIPeter Zijlstra2007-10-171-2/+10
| | | | | | | | Count per BDI writeback pages. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: count reclaimable pages per BDIPeter Zijlstra2007-10-171-0/+4
| | | | | | | | Count per BDI reclaimable pages; nr_reclaimable = nr_dirty + nr_unstable. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memoryless nodes: fixup uses of node_online_map in generic codeLee Schermerhorn2007-10-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Here's a cut at fixing up uses of the online node map in generic code. mm/shmem.c:shmem_parse_mpol() Ensure nodelist is subset of nodes with memory. Use node_states[N_HIGH_MEMORY] as default for missing nodelist for interleave policy. mm/shmem.c:shmem_fill_super() initialize policy_nodes to node_states[N_HIGH_MEMORY] mm/page-writeback.c:highmem_dirtyable_memory() sum over nodes with memory mm/page_alloc.c:zlc_setup() allowednodes - use nodes with memory. mm/page_alloc.c:default_zonelist_order() average over nodes with memory. mm/page_alloc.c:find_next_best_node() skip nodes w/o memory. N_HIGH_MEMORY state mask may not be initialized at this time, unless we want to depend on early_calculate_totalpages() [see below]. Will ZONE_MOVABLE ever be configurable? mm/page_alloc.c:find_zone_movable_pfns_for_nodes() spread kernelcore over nodes with memory. This required calling early_calculate_totalpages() unconditionally, and populating N_HIGH_MEMORY node state therein from nodes in the early_node_map[]. If we can depend on this, we can eliminate the population of N_HIGH_MEMORY mask from __build_all_zonelists() and use the N_HIGH_MEMORY mask in find_next_best_node(). mm/mempolicy.c:mpol_check_policy() Ensure nodes specified for policy are subset of nodes with memory. [akpm@linux-foundation.org: fix warnings] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Acked-by: Christoph Lameter <clameter@sgi.com> Cc: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: use lockless radix-tree probeNick Piggin2007-10-161-5/+3
| | | | | | | | | Probing pages and radix_tree_tagged are lockless operations with the lockless radix-tree. Convert these users to RCU locking rather than using tree_lock. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: set_page_dirty_balance() vs ->page_mkwrite()Peter Zijlstra2007-10-081-2/+2
| | | | | | | | | | | | | | All the current page_mkwrite() implementations also set the page dirty. Which results in the set_page_dirty_balance() call to _not_ call balance, because the page is already found dirty. This allows us to dirty a _lot_ of pages without ever hitting balance_dirty_pages(). Not good (tm). Force a balance call if ->page_mkwrite() was successful. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* move page writeback acounting out of macrosAndrew Morton2007-07-191-0/+4
| | | | | | | | | | | | page-writeback accounting is presently performed in the page-flags macros. This is inconsistent and a bit ugly and makes it awkward to implement per-backing_dev under-writeback page accounting. So move this accounting down to the callsite(s). Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: share PG_readahead and PG_reclaimFengguang Wu2007-07-191-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Share the same page flag bit for PG_readahead and PG_reclaim. One is used only on file reads, another is only for emergency writes. One is used mostly for fresh/young pages, another is for old pages. Combinations of possible interactions are: a) clear PG_reclaim => implicit clear of PG_readahead it will delay an asynchronous readahead into a synchronous one it actually does _good_ for readahead: the pages will be reclaimed soon, it's readahead thrashing! in this case, synchronous readahead makes more sense. b) clear PG_readahead => implicit clear of PG_reclaim one(and only one) page will not be reclaimed in time it can be avoided by checking PageWriteback(page) in readahead first c) set PG_reclaim => implicit set of PG_readahead will confuse readahead and make it restart the size rampup process it's a trivial problem, and can mostly be avoided by checking PageWriteback(page) first in readahead d) set PG_readahead => implicit set of PG_reclaim PG_readahead will never be set on already cached pages. PG_reclaim will always be cleared on dirtying a page. so not a problem. In summary, a) we get better behavior b,d) possible interactions can be avoided c) racy condition exists that might affect readahead, but the chance is _really_ low, and the hurt on readahead is trivial. Compound pages also use PG_reclaim, but for now they do not interact with reclaim/readahead code. Signed-off-by: Fengguang Wu <wfg@mail.ustc.edu.cn> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix clear_page_dirty_for_io vs fault raceNick Piggin2007-07-191-5/+12
| | | | | | | | | | | | | | Fix msync data loss and (less importantly) dirty page accounting inaccuracies due to the race remaining in clear_page_dirty_for_io(). The deleted comment explains what the race was, and the added comments explain how it is fixed. Signed-off-by: Nick Piggin <npiggin@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: introduce some page/buffer invariantsNick Piggin2007-07-171-0/+1
| | | | | | | | | | | | | | | | | | | | | | It is a bug to set a page dirty if it is not uptodate unless it has buffers. If the page has buffers, then the page may be dirty (some buffers dirty) but not uptodate (some buffers not uptodate). The exception to this rule is if the set_page_dirty caller is racing with truncate or invalidate. A buffer can not be set dirty if it is not uptodate. If either of these situations occurs, it indicates there could be some data loss problem. Some of these warnings could be a harmless one where the page or buffer is set uptodate immediately after it is dirtied, however we should fix those up, and enforce this ordering. Bring the order of operations for truncate into line with those of invalidate. This will prevent a page from being able to go !uptodate while we're holding the tree_lock, which is probably a good thing anyway. Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dirty_writeback_centisecs_handler() cleanupAndrew Morton2007-07-161-6/+4
| | | | | | | Repair indenting bustage. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* consolidate generic_writepages and mpage_writepagesMiklos Szeredi2007-05-111-19/+40
| | | | | | | | | | | | | | | | | | Clean up massive code duplication between mpage_writepages() and generic_writepages(). The new generic function, write_cache_pages() takes a function pointer argument, which will be called for each page to be written. Maybe cifs_writepages() too can use this infrastructure, but I'm not touching that with a ten-foot pole. The upcoming page writeback support in fuse will also want this. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Acked-by: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Factor outstanding I/O error handlingGuillaume Chazarain2007-05-081-6/+1
| | | | | | | | | | Cleanup: setting an outstanding error on a mapping was open coded too many times. Factor it out in mapping_set_error(). Signed-off-by: Guillaume Chazarain <guichaz@yahoo.fr> Cc: Steven Whitehouse <swhiteho@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Use ZVC counters to establish exact size of dirtyable pagesChristoph Lameter2007-05-071-10/+40
| | | | | | | | | | | | | | | | | | | | | | | | | | | We can use the global ZVC counters to establish the exact size of the LRU and the free pages. This allows a more accurate determination of the dirty ratio. This patch will fix the broken ratio calculations if large amounts of memory are allocated to huge pags or other consumers that do not put the pages on to the LRU. Notes: - I did not add NR_SLAB_RECLAIMABLE to the calculation of the dirtyable pages. Those may be reclaimable but they are at this point not dirtyable. If NR_SLAB_RECLAIMABLE would be considered then a huge number of reclaimable pages would stop writeback from occurring. - This patch used to be in mm as the last one in a series of patches. It was removed when Linus updated the treatment of highmem because there was a conflict. I updated the patch to follow Linus' approach. This patch is neede to fulfill the claims made in the beginning of the patchset that is now in Linus' tree. Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Change default dirty-writeback limitsLinus Torvalds2007-04-271-2/+2
| | | | | | | | | Do this really early in the 2.6.22-rc series, so that we'll get feedback. And don't change by half measures. Just cut the default dirty limit to a quarter of what it was, and see if anybody even notices. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] throttle_vm_writeout(): don't loop on GFP_NOFS and GFP_NOIO allocationsAndrew Morton2007-03-011-2/+11
| | | | | | | | | | | | | | | | throttle_vm_writeout() is designed to wait for the dirty levels to subside. But if the caller holds IO or FS locks, we might be holding up that writeout. So change it to take a single nap to give other devices a chance to clean some memory, then return. Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Pete Zaitcev <zaitcev@redhat.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Change constant zero to NOTIFY_DONE in ratelimit_handler()Paul E. McKenney2007-02-111-1/+1
| | | | | | | | | Change a hard-coded constant 0 to the symbolic equivalent NOTIFY_DONE in the ratelimit_handler() CPU notifier handler function. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] Numerous fixes to kernel-doc info in source files.Robert P. J. Day2007-02-111-4/+1
| | | | | | | | | | | | | | | A variety of (mostly) innocuous fixes to the embedded kernel-doc content in source files, including: * make multi-line initial descriptions single line * denote some function names, constants and structs as such * change erroneous opening '/*' to '/**' in a few places * reword some text for clarity Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Cc: "Randy.Dunlap" <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] simplify shmem_aops.set_page_dirty() methodKen Chen2007-02-111-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | shmem backed file does not have page writeback, nor it participates in backing device's dirty or writeback accounting. So using generic __set_page_dirty_nobuffers() for its .set_page_dirty aops method is a bit overkill. It unnecessarily prolongs shm unmap latency. For example, on a densely populated large shm segment (sevearl GBs), the unmapping operation becomes painfully long. Because at unmap, kernel transfers dirty bit in PTE into page struct and to the radix tree tag. The operation of tagging the radix tree is particularly expensive because it has to traverse the tree from the root to the leaf node on every dirty page. What's bothering is that radix tree tag is used for page write back. However, shmem is memory backed and there is no page write back for such file system. And in the end, we spend all that time tagging radix tree and none of that fancy tagging will be used. So let's simplify it by introduce a new aops __set_page_dirty_no_writeback and this will speed up shm unmap. Signed-off-by: Ken Chen <kenchen@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix balance_dirty_page() calculations with CONFIG_HIGHMEMLinus Torvalds2007-01-301-23/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This makes balance_dirty_page() always base its calculations on the amount of non-highmem memory in the machine, rather than try to base it on total memory and then falling back on non-highmem memory if the mapping it was writing wasn't highmem capable. This not only fixes a situation where two different writers can have wildly different notions about what is a "balanced" dirty state, but it also means that people with highmem machines don't run into an OOM situation when regular memory fills up with dirty pages. We used to try to handle the latter case by scaling down the dirty_ratio if the machine had a lot of highmem pages in page_writeback_init(), but it wasn't aggressive enough for some situations, and since basing the dirty ratio on highmem memory was broken in the first place, let's just stop doing so. (A variation of this theme fixed Justin Piszcz's OOM problem when copying an 18GB file on a RAID setup). Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Justin Piszcz <jpiszcz@lucidpixels.com> Cc: Andrew Morton <akpm@osdl.org> Cc: Neil Brown <neilb@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Christoph Lameter <clameter@sgi.com> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Adrian Bunk <bunk@stusta.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* VM: Fix nasty and subtle race in shared mmap'ed page writebackLinus Torvalds2006-12-291-8/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The VM layer (on the face of it, fairly reasonably) expected that when it does a ->writepage() call to the filesystem, it would write out the full page at that point in time. Especially since it had earlier marked the whole page dirty with "set_page_dirty()". But that isn't actually the case: ->writepage() does not actually write a page, it writes the parts of the page that have been explicitly marked dirty before, *and* that had not got written out for other reasons since the last time we told it they were dirty. That last caveat is the important one. Which _most_ of the time ends up being the whole page (since we had called "set_page_dirty()" on the page earlier), but if the filesystem had done any dirty flushing of its own (for example, to honor some internal write ordering guarantees), it might end up doing only a partial page IO (or none at all) when ->writepage() is actually called. That is the correct thing in general (since we actually often _want_ only the known-dirty parts of the page to be written out), but the shared dirty page handling had implicitly forgotten about these details, and had a number of cases where it was doing just the "->writepage()" part, without telling the low-level filesystem that the whole page might have been re-dirtied as part of being mapped writably into user space. Since most of the time the FS did actually write out the full page, we didn't notice this for a loong time, and this needed some really odd patterns to trigger. But it caused occasional corruption with rtorrent and with the Debian "apt" database, because both use shared mmaps to update the end result. This fixes it. Finally. After way too much hair-pulling. Acked-by: Nick Piggin <nickpiggin@yahoo.com.au> Acked-by: Martin J. Bligh <mbligh@google.com> Acked-by: Martin Michlmayr <tbm@cyrius.com> Acked-by: Martin Johansson <martin@fatbob.nu> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Andrei Popa <andrei.popa@i-neo.ro> Cc: High Dickins <hugh@veritas.com> Cc: Andrew Morton <akpm@osdl.org>, Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Segher Boessenkool <segher@kernel.crashing.org> Cc: David Miller <davem@davemloft.net> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Gordon Farquharson <gordonfarquharson@gmail.com> Cc: Guillaume Chazarain <guichaz@yahoo.fr> Cc: Theodore Tso <tytso@mit.edu> Cc: Kenneth Cheng <kenneth.w.chen@intel.com> Cc: Tobias Diedrich <ranma@tdiedrich.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* VM: Remove "clear_page_dirty()" and "test_clear_page_dirty()" functionsLinus Torvalds2006-12-211-32/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | They were horribly easy to mis-use because of their tempting naming, and they also did way more than any users of them generally wanted them to do. A dirty page can become clean under two circumstances: (a) when we write it out. We have "clear_page_dirty_for_io()" for this, and that function remains unchanged. In the "for IO" case it is not sufficient to just clear the dirty bit, you also have to mark the page as being under writeback etc. (b) when we actually remove a page due to it becoming inaccessible to users, notably because it was truncate()'d away or the file (or metadata) no longer exists, and we thus want to cancel any outstanding dirty state. For the (b) case, we now introduce "cancel_dirty_page()", which only touches the page state itself, and verifies that the page is not mapped (since cancelling writes on a mapped page would be actively wrong as it is still accessible to users). Some filesystems need to be fixed up for this: CIFS, FUSE, JFS, ReiserFS, XFS all use the old confusing functions, and will be fixed separately in subsequent commits (with some of them just removing the offending logic, and others using clear_page_dirty_for_io()). This was confirmed by Martin Michlmayr to fix the apt database corruption on ARM. Cc: Martin Michlmayr <tbm@cyrius.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hugh Dickins <hugh@veritas.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Andrei Popa <andrei.popa@i-neo.ro> Cc: Andrew Morton <akpm@osdl.org> Cc: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Cc: Gordon Farquharson <gordonfarquharson@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] io-accounting: write accountingAndrew Morton2006-12-101-1/+4
| | | | | | | | | | | | | | | | | | | | Accounting writes is fairly simple: whenever a process flips a page from clean to dirty, we accuse it of having caused a write to underlying storage of PAGE_CACHE_SIZE bytes. This may overestimate the amount of writing: the page-dirtying may cause only one buffer_head's worth of writeout. Fixing that is possible, but probably a bit messy and isn't obviously important. Cc: Jay Lan <jlan@sgi.com> Cc: Shailabh Nagar <nagar@watson.ibm.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Chris Sturtivant <csturtiv@sgi.com> Cc: Tony Ernst <tee@sgi.com> Cc: Guillaume Thouvenin <guillaume.thouvenin@bull.net> Cc: David Wright <daw@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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