path: root/mm/backing-dev.c
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2009-12-03flusher: Fix PF_FROZEN raceOGAWA Hirofumi
To touch task->flags directly is racy. thaw_process() still has race (changing non_current->flags, but this is another issue) though, I think it's much better off. So, use thaw_process() instead. Signed-off-by: OGAWA Hirofumi <> Signed-off-by: Jens Axboe <>
2009-11-12Thaw refrigerated bdi flusher threads before invoking kthread_stop on themRomit Dasgupta
Unfreezes the bdi flusher task when the said task needs to exit. Steps to reproduce this. 1) Mount a file system from MMC/SD card. 2) Unmount the file system. This creates a flusher task. 3) Attempt suspend to RAM. System is unresponsive. This is because the bdi flusher thread is already in the refrigerator and will remain so until it is thawed. The MMC driver suspend routine call stack will ultimately issue a 'kthread_stop' on the bdi flusher thread and will block until the flusher thread is exited. Since the bdi flusher thread is in the refrigerator it never cleans up until thawed. Signed-off-by: Romit Dasgupta <> Signed-off-by: Jens Axboe <>
2009-11-03backing-dev: bdi sb prune should be in the unregister path, not destroyJens Axboe
Commit 592b09a42fc3ae6737a0f3ecf4fee42ecd0296f8 was different from the tested path, in that it moved the bdi super_block prune from unregister to destroy context. This doesn't fully fix the sync hang bug on unexpected device removal, as need to prune the bdi cache pointer before killing flusher thread. Tested-by: Artur Skawina <> Signed-off-by: Jens Axboe <>
2009-10-29backing-dev: ensure that a removed bdi no longer has super_block referencing itJens Axboe
When the bdi is being removed, we have to ensure that no super_blocks currently have that cached in sb->s_bdi. Normally this is ensured by the sb having a longer life span than the bdi, but if the device is suddenly yanked, we have to kill this reference. sb->s_bdi is pointed to freed memory at that point. This fixes a problem with sync(1) hanging when a USB stick is pulled without cleanly umounting it first. Reported-by: Pavel Machek <> Signed-off-by: Jens Axboe <>
2009-10-09writeback: kill space in debugfs item nameWu Fengguang
The space is not script friendly, kill it. Signed-off-by: Wu Fengguang <> Signed-off-by: Jens Axboe <>
2009-09-16writeback: splice dirty inode entries to default bdi on bdi_destroy()Jens Axboe
We cannot safely ensure that the inodes are all gone at this point in time, and we must not destroy this bdi with inodes having off it. So just splice our entries to the default bdi since that one will always persist. Signed-off-by: Jens Axboe <>
2009-09-16writeback: use RCU to protect bdi_listJens Axboe
Now that bdi_writeback_all() no longer handles integrity writeback, it doesn't have to block anymore. This means that we can switch bdi_list reader side protection to RCU. Signed-off-by: Jens Axboe <>
2009-09-11writeback: check for registered bdi in flusher add and inode dirtyJens Axboe
Also a debugging aid. We want to catch dirty inodes being added to backing devices that don't do writeback. Signed-off-by: Jens Axboe <>
2009-09-11writeback: add name to backing_dev_infoJens Axboe
This enables us to track who does what and print info. Its main use is catching dirty inodes on the default_backing_dev_info, so we can fix that up. Signed-off-by: Jens Axboe <>
2009-09-11writeback: add some debug inode list counters to bdi statsJens Axboe
Add some debug entries to be able to inspect the internal state of the writeback details. Signed-off-by: Jens Axboe <>
2009-09-11writeback: switch to per-bdi threads for flushing dataJens Axboe
This gets rid of pdflush for bdi writeout and kupdated style cleaning. pdflush writeout suffers from lack of locality and also requires more threads to handle the same workload, since it has to work in a non-blocking fashion against each queue. This also introduces lumpy behaviour and potential request starvation, since pdflush can be starved for queue access if others are accessing it. A sample ffsb workload that does random writes to files is about 8% faster here on a simple SATA drive during the benchmark phase. File layout also seems a LOT more smooth in vmstat: r b swpd free buff cache si so bi bo in cs us sy id wa 0 1 0 608848 2652 375372 0 0 0 71024 604 24 1 10 48 42 0 1 0 549644 2712 433736 0 0 0 60692 505 27 1 8 48 44 1 0 0 476928 2784 505192 0 0 4 29540 553 24 0 9 53 37 0 1 0 457972 2808 524008 0 0 0 54876 331 16 0 4 38 58 0 1 0 366128 2928 614284 0 0 4 92168 710 58 0 13 53 34 0 1 0 295092 3000 684140 0 0 0 62924 572 23 0 9 53 37 0 1 0 236592 3064 741704 0 0 4 58256 523 17 0 8 48 44 0 1 0 165608 3132 811464 0 0 0 57460 560 21 0 8 54 38 0 1 0 102952 3200 873164 0 0 4 74748 540 29 1 10 48 41 0 1 0 48604 3252 926472 0 0 0 53248 469 29 0 7 47 45 where vanilla tends to fluctuate a lot in the creation phase: r b swpd free buff cache si so bi bo in cs us sy id wa 1 1 0 678716 5792 303380 0 0 0 74064 565 50 1 11 52 36 1 0 0 662488 5864 319396 0 0 4 352 302 329 0 2 47 51 0 1 0 599312 5924 381468 0 0 0 78164 516 55 0 9 51 40 0 1 0 519952 6008 459516 0 0 4 78156 622 56 1 11 52 37 1 1 0 436640 6092 541632 0 0 0 82244 622 54 0 11 48 41 0 1 0 436640 6092 541660 0 0 0 8 152 39 0 0 51 49 0 1 0 332224 6200 644252 0 0 4 102800 728 46 1 13 49 36 1 0 0 274492 6260 701056 0 0 4 12328 459 49 0 7 50 43 0 1 0 211220 6324 763356 0 0 0 106940 515 37 1 10 51 39 1 0 0 160412 6376 813468 0 0 0 8224 415 43 0 6 49 45 1 1 0 85980 6452 886556 0 0 4 113516 575 39 1 11 54 34 0 2 0 85968 6452 886620 0 0 0 1640 158 211 0 0 46 54 A 10 disk test with btrfs performs 26% faster with per-bdi flushing. A SSD based writeback test on XFS performs over 20% better as well, with the throughput being very stable around 1GB/sec, where pdflush only manages 750MB/sec and fluctuates wildly while doing so. Random buffered writes to many files behave a lot better as well, as does random mmap'ed writes. A separate thread is added to sync the super blocks. In the long term, adding sync_supers_bdi() functionality could get rid of this thread again. Signed-off-by: Jens Axboe <>
2009-09-11writeback: move dirty inodes from super_block to backing_dev_infoJens Axboe
This is a first step at introducing per-bdi flusher threads. We should have no change in behaviour, although sb_has_dirty_inodes() is now ridiculously expensive, as there's no easy way to answer that question. Not a huge problem, since it'll be deleted in subsequent patches. Signed-off-by: Jens Axboe <>
2009-07-10Fix congestion_wait() sync/async vs read/write confusionJens Axboe
Commit 1faa16d22877f4839bd433547d770c676d1d964c accidentally broke the bdi congestion wait queue logic, causing us to wait on congestion for WRITE (== 1) when we really wanted BLK_RW_ASYNC (== 0) instead. Signed-off-by: Jens Axboe <>
2009-04-06block: change the request allocation/congestion logic to be sync/async basedJens Axboe
This makes sure that we never wait on async IO for sync requests, instead of doing the split on writes vs reads. Signed-off-by: Jens Axboe <> Signed-off-by: Linus Torvalds <>
2009-03-26Move the default_backing_dev_info out of readahead.c and into backing-dev.cJens Axboe
It really makes no sense to have it in readahead.c, so move it where it belongs. Signed-off-by: Jens Axboe <>
2009-01-06Merge branch 'core-fixes-for-linus' of ↵Linus Torvalds
git:// * 'core-fixes-for-linus' of git:// rcu: fix rcutorture bug rcu: eliminate synchronize_rcu_xxx macro rcu: make treercu safe for suspend and resume rcu: fix rcutree grace-period-latency bug on small systems futex: catch certain assymetric (get|put)_futex_key calls futex: make futex_(get|put)_key() calls symmetric locking, percpu counters: introduce separate lock classes swiotlb: clean up EXPORT_SYMBOL usage swiotlb: remove unnecessary declaration swiotlb: replace architecture-specific swiotlb.h with linux/swiotlb.h swiotlb: add support for systems with highmem swiotlb: store phys address in io_tlb_orig_addr array swiotlb: add hwdev to swiotlb_phys_to_bus() / swiotlb_sg_to_bus()
2009-01-06mm: change dirty limit type specifiers to unsigned longDavid Rientjes
The background dirty and dirty limits are better defined with type specifiers of unsigned long since negative writeback thresholds are not possible. These values, as returned by get_dirty_limits(), are normally compared with ZVC values to determine whether writeback shall commence or be throttled. Such page counts cannot be negative, so declaring the page limits as signed is unnecessary. Acked-by: Peter Zijlstra <> Cc: Dave Chinner <> Cc: Christoph Lameter <> Signed-off-by: David Rientjes <> Cc: Andrea Righi <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2009-01-06Merge branches 'core/futexes', 'core/locking', 'core/rcu' and 'linus' into ↵Ingo Molnar
2008-12-29locking, percpu counters: introduce separate lock classesPeter Zijlstra
Impact: fix lockdep false positives Classify percpu_counter instances similar to regular lock objects -- that is, per instantiation site. The networking code has increased its use of percpu_counters, which leads to false positives if they are treated as a single class. Signed-off-by: Peter Zijlstra <> Signed-off-by: Ingo Molnar <>
2008-12-10mm/backing-dev.c: remove recently-added WARN_ON()Andrew Morton
On second thoughts, this is just going to disturb people while telling us things which we already knew. Cc: Peter Korsgaard <> Cc: Peter Zijlstra <> Cc: Kay Sievers <> Cc: David Woodhouse <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-12-02bdi: register sysfs bdi device only once per queueKay Sievers
Devices which share the same queue, like floppies and mtd devices, get registered multiple times in the bdi interface, but bdi accounts only the last registered device of the devices sharing one queue. On remove, all earlier registered devices leak, stay around in sysfs, and cause "duplicate filename" errors if the devices are re-created. This prevents the creation of multiple bdi interfaces per queue, and the bdi device will carry the dev_t name of the block device which is the first one registered, of the pool of devices using the same queue. [ add a WARN_ON so we know which drivers are misbehaving] Tested-by: Peter Korsgaard <> Acked-by: Peter Zijlstra <> Signed-off-by: Kay Sievers <> Cc: David Woodhouse <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-05-20mm: bdi: fix race in bdi_class device creationGreg Kroah-Hartman
There is a race from when a device is created with device_create() and then the drvdata is set with a call to dev_set_drvdata() in which a sysfs file could be open, yet the drvdata will be NULL, causing all sorts of bad things to happen. This patch fixes the problem by using the new function, device_create_vargs(). Many thanks to Arthur Jones <> for reporting the bug, and testing patches out. Cc: Kay Sievers <> Cc: Arthur Jones <> Cc: Peter Zijlstra <> Cc: Miklos Szeredi <> Signed-off-by: Greg Kroah-Hartman <>
2008-04-30mm: bdi: move statistics to debugfsMiklos Szeredi
Move BDI statistics to debugfs: /sys/kernel/debug/bdi/<bdi>/stats Use postcore_initcall() to initialize the sysfs class and debugfs, because debugfs is initialized in core_initcall(). Update descriptions in ABI documentation. Signed-off-by: Miklos Szeredi <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-04-30mm: bdi: allow setting a maximum for the bdi dirty limitPeter Zijlstra
Add "max_ratio" to /sys/class/bdi. This indicates the maximum percentage of the global dirty threshold allocated to this bdi. [] - 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 <> Signed-off-by: Miklos Szeredi <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-04-30mm: bdi: allow setting a minimum for the bdi dirty limitPeter Zijlstra
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. [] - fix parsing in min_ratio_store() - document new sysfs attribute Signed-off-by: Peter Zijlstra <> Signed-off-by: Miklos Szeredi <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2008-04-30mm: bdi: export BDI attributes in sysfsPeter Zijlstra
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 [] - 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 [ fix ia64 warning] Signed-off-by: Peter Zijlstra <> Cc: Kay Sievers <> Acked-by: Greg KH <> Cc: Trond Myklebust <> Signed-off-by: Miklos Szeredi <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-12-05mm/backing-dev.c: fix percpu_counter_destroy call bug in bdi_initDenis Cheng
this call should use the array index j, not i. But with this approach, just one int i is enough, int j is not needed. Signed-off-by: Denis Cheng <> Cc: Peter Zijlstra <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17mm: per device dirty thresholdPeter Zijlstra
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. [ fix warnings] [ Fix occasional hang when a task couldn't get out of balance_dirty_pages] Signed-off-by: Peter Zijlstra <> Signed-off-by: Hugh Dickins <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17mm: scalable bdi statistics countersPeter Zijlstra
Provide scalable per backing_dev_info statistics counters. Signed-off-by: Peter Zijlstra <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-10-17nfs: remove congestion_end()Peter Zijlstra
These patches aim to improve balance_dirty_pages() and directly address three issues: 1) inter device starvation 2) stacked device deadlocks 3) inter process starvation 1 and 2 are a direct result from removing the global dirty limit and using per device dirty limits. By giving each device its own dirty limit is will no longer starve another device, and the cyclic dependancy on the dirty limit is broken. In order to efficiently distribute the dirty limit across the independant devices a floating proportion is used, this will allocate a share of the total limit proportional to the device's recent activity. 3 is done by also scaling the dirty limit proportional to the current task's recent dirty rate. This patch: nfs: remove congestion_end(). It's redundant, clear_bdi_congested() already wakes the waiters. Signed-off-by: Peter Zijlstra <> Cc: Trond Myklebust <> Cc: "J. Bruce Fields" <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-07-16remove mm/backing-dev.c:congestion_wait_interruptible()Adrian Bunk
congestion_wait_interruptible() is no longer used. Signed-off-by: Adrian Bunk <> Acked-by: Trond Myklebust <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2007-03-16[PATCH] nfs: fix congestion controlPeter Zijlstra
The current NFS client congestion logic is severly broken, it marks the backing device congested during each nfs_writepages() call but doesn't mirror this in nfs_writepage() which makes for deadlocks. Also it implements its own waitqueue. Replace this by a more regular congestion implementation that puts a cap on the number of active writeback pages and uses the bdi congestion waitqueue. Also always use an interruptible wait since it makes sense to be able to SIGKILL the process even for mounts without 'intr'. Signed-off-by: Peter Zijlstra <> Acked-by: Trond Myklebust <> Cc: Christoph Lameter <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
2006-10-20[PATCH] separate bdi congestion functions from queue congestion functionsAndrew Morton
Separate out the concept of "queue congestion" from "backing-dev congestion". Congestion is a backing-dev concept, not a queue concept. The blk_* congestion functions are retained, as wrappers around the core backing-dev congestion functions. This proper layering is needed so that NFS can cleanly use the congestion functions, and so that CONFIG_BLOCK=n actually links. Cc: "Thomas Maier" <> Cc: "Jens Axboe" <> Cc: Trond Myklebust <> Cc: David Howells <> Cc: Peter Osterlund <> Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>