When sync does it's WB_SYNC_ALL writeback, it issues data Io and
then immediately waits for IO completion. This is done in the
context of the flusher thread, and hence completely ties up the
flusher thread for the backing device until all the dirty inodes
have been synced. On filesystems that are dirtying inodes constantly
and quickly, this means the flusher thread can be tied up for
minutes per sync call and hence badly affect system level write IO
performance as the page cache cannot be cleaned quickly.
We already have a wait loop for IO completion for sync(2), so cut
this out of the flusher thread and delegate it to wait_sb_inodes().
Hence we can do rapid IO submission, and then wait for it all to
complete.
Effect of sync on fsmark before the patch:
FSUse% Count Size Files/sec App Overhead
.....
0 640000 4096 35154.6 1026984
0 720000 4096 36740.3 1023844
0 800000 4096 36184.6 916599
0 880000 4096 1282.7 1054367
0 960000 4096 3951.3 918773
0 1040000 4096 40646.2 996448
0 1120000 4096 43610.1 895647
0 1200000 4096 40333.1 921048
And a single sync pass took:
real 0m52.407s
user 0m0.000s
sys 0m0.090s
After the patch, there is no impact on fsmark results, and each
individual sync(2) operation run concurrently with the same fsmark
workload takes roughly 7s:
real 0m6.930s
user 0m0.000s
sys 0m0.039s
IOWs, sync is 7-8x faster on a busy filesystem and does not have an
adverse impact on ongoing async data write operations.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull block core updates from Jens Axboe:
- Major bit is Kents prep work for immutable bio vecs.
- Stable candidate fix for a scheduling-while-atomic in the queue
bypass operation.
- Fix for the hang on exceeded rq->datalen 32-bit unsigned when merging
discard bios.
- Tejuns changes to convert the writeback thread pool to the generic
workqueue mechanism.
- Runtime PM framework, SCSI patches exists on top of these in James'
tree.
- A few random fixes.
* 'for-3.10/core' of git://git.kernel.dk/linux-block: (40 commits)
relay: move remove_buf_file inside relay_close_buf
partitions/efi.c: replace useless kzalloc's by kmalloc's
fs/block_dev.c: fix iov_shorten() criteria in blkdev_aio_read()
block: fix max discard sectors limit
blkcg: fix "scheduling while atomic" in blk_queue_bypass_start
Documentation: cfq-iosched: update documentation help for cfq tunables
writeback: expose the bdi_wq workqueue
writeback: replace custom worker pool implementation with unbound workqueue
writeback: remove unused bdi_pending_list
aoe: Fix unitialized var usage
bio-integrity: Add explicit field for owner of bip_buf
block: Add an explicit bio flag for bios that own their bvec
block: Add bio_alloc_pages()
block: Convert some code to bio_for_each_segment_all()
block: Add bio_for_each_segment_all()
bounce: Refactor __blk_queue_bounce to not use bi_io_vec
raid1: use bio_copy_data()
pktcdvd: Use bio_reset() in disabled code to kill bi_idx usage
pktcdvd: use bio_copy_data()
block: Add bio_copy_data()
...
Writeback has been recently converted to use workqueue instead of its
private thread pool implementation. One negative side effect of this
conversion is that there's no easy to tell which backing device a
writeback work item was working on at the time of task dump, be it
sysrq-t, BUG, WARN or whatever, which, according to our writeback
brethren, is important in tracking down issues with a lot of mounted
file systems on a lot of different devices.
This patch restores that information using the new worker description
facility. bdi_writeback_workfn() calls set_work_desc() to identify
which bdi it's working on. The description is printed out together with
the worqueue name and worker function as in the following example dump.
WARNING: at fs/fs-writeback.c:1015 bdi_writeback_workfn+0x2b4/0x3c0()
Modules linked in:
Pid: 28, comm: kworker/u18:0 Not tainted 3.9.0-rc1-work+ #24 empty empty/S3992
Workqueue: writeback bdi_writeback_workfn (flush-8:16)
ffffffff820a3a98 ffff88015b927cb8 ffffffff81c61855 ffff88015b927cf8
ffffffff8108f500 0000000000000000 ffff88007a171948 ffff88007a1716b0
ffff88015b49df00 ffff88015b8d3940 0000000000000000 ffff88015b927d08
Call Trace:
[<ffffffff81c61855>] dump_stack+0x19/0x1b
[<ffffffff8108f500>] warn_slowpath_common+0x70/0xa0
[<ffffffff8108f54a>] warn_slowpath_null+0x1a/0x20
[<ffffffff81200144>] bdi_writeback_workfn+0x2b4/0x3c0
[<ffffffff810b4c87>] process_one_work+0x1d7/0x660
[<ffffffff810b5c72>] worker_thread+0x122/0x380
[<ffffffff810bdfea>] kthread+0xea/0xf0
[<ffffffff81c6cedc>] ret_from_fork+0x7c/0xb0
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Writeback implements its own worker pool - each bdi can be associated
with a worker thread which is created and destroyed dynamically. The
worker thread for the default bdi is always present and serves as the
"forker" thread which forks off worker threads for other bdis.
there's no reason for writeback to implement its own worker pool when
using unbound workqueue instead is much simpler and more efficient.
This patch replaces custom worker pool implementation in writeback
with an unbound workqueue.
The conversion isn't too complicated but the followings are worth
mentioning.
* bdi_writeback->last_active, task and wakeup_timer are removed.
delayed_work ->dwork is added instead. Explicit timer handling is
no longer necessary. Everything works by either queueing / modding
/ flushing / canceling the delayed_work item.
* bdi_writeback_thread() becomes bdi_writeback_workfn() which runs off
bdi_writeback->dwork. On each execution, it processes
bdi->work_list and reschedules itself if there are more things to
do.
The function also handles low-mem condition, which used to be
handled by the forker thread. If the function is running off a
rescuer thread, it only writes out limited number of pages so that
the rescuer can serve other bdis too. This preserves the flusher
creation failure behavior of the forker thread.
* INIT_LIST_HEAD(&bdi->bdi_list) is used to tell
bdi_writeback_workfn() about on-going bdi unregistration so that it
always drains work_list even if it's running off the rescuer. Note
that the original code was broken in this regard. Under memory
pressure, a bdi could finish unregistration with non-empty
work_list.
* The default bdi is no longer special. It now is treated the same as
any other bdi and bdi_cap_flush_forker() is removed.
* BDI_pending is no longer used. Removed.
* Some tracepoints become non-applicable. The following TPs are
removed - writeback_nothread, writeback_wake_thread,
writeback_wake_forker_thread, writeback_thread_start,
writeback_thread_stop.
Everything, including devices coming and going away and rescuer
operation under simulated memory pressure, seems to work fine in my
test setup.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Add tracepoints for page dirtying, writeback_single_inode start, inode
dirtying and writeback. For the latter two inode events, a pair of
events are defined to denote start and end of the operations (the
starting one has _start suffix and the one w/o suffix happens after
the operation is complete). These inode ops are FS specific and can
be non-trivial and having enclosing tracepoints is useful for external
tracers.
This is part of tracepoint additions to improve visiblity into
dirtying / writeback operations for io tracer and userland.
v2: writeback_dirty_inode[_start] TPs may be called for files on
pseudo FSes w/ unregistered bdi. Check whether bdi->dev is %NULL
before dereferencing.
v3: buffer dirtying moved to a block TP.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
writeback_inodes_sb(_nr)_if_idle() is re-implemented by replacing down_read()
with down_read_trylock() because
- If ->s_umount is write locked, then the sb is not idle. That is
writeback_inodes_sb(_nr)_if_idle() needn't wait for the lock.
- writeback_inodes_sb(_nr)_if_idle() grabs s_umount lock when it want to start
writeback, it may bring us deadlock problem when doing umount. In order to
fix the problem, ext4 and btrfs implemented their own writeback functions
instead of writeback_inodes_sb(_nr)_if_idle(), but it introduced the redundant
code, it is better to implement a new writeback_inodes_sb(_nr)_if_idle().
The name of these two functions is cumbersome, so rename them to
try_to_writeback_inodes_sb(_nr).
This idea came from Christoph Hellwig.
Some code is from the patch of Kamal Mostafa.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Yan Hong <clouds.yan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 169ebd9013 ("writeback: Avoid iput() from flusher thread")
removed iget-iput pair from inode writeback. As a side effect, inodes
that are dirty during iput_final() call won't be ever added to inode LRU
(iput_final() doesn't add dirty inodes to LRU and later when the inode
is cleaned there's noone to add the inode there). Thus inodes are
effectively unreclaimable until someone looks them up again.
The practical effect of this bug is limited by the fact that inodes are
pinned by a dentry for long enough that the inode gets cleaned. But
still the bug can have nasty consequences leading up to OOM conditions
under certain circumstances. Following can easily reproduce the
problem:
for (( i = 0; i < 1000; i++ )); do
mkdir $i
for (( j = 0; j < 1000; j++ )); do
touch $i/$j
echo 2 > /proc/sys/vm/drop_caches
done
done
then one needs to run 'sync; ls -lR' to make inodes reclaimable again.
We fix the issue by inserting unused clean inodes into the LRU after
writeback finishes in inode_sync_complete().
Signed-off-by: Jan Kara <jack@suse.cz>
Reported-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: <stable@vger.kernel.org> [3.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull writeback fixes from Fengguang Wu:
"Three trivial writeback fixes"
* 'writeback-for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
CPU hotplug, writeback: Don't call writeback_set_ratelimit() too often during hotplug
writeback: correct comment for move_expired_inodes()
backing-dev: use kstrto* in preference to simple_strtoul
The parameter 'wb' is never used in this function.
Signed-off-by: Yan Hong <clouds.yan@gmail.com>
Acked-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>
using the meta_bg feature. This allows us to resize file systems
which are greater than 16TB. In addition, the speed of online
resizing has been improved in general.
We also fix a number of races, some of which could lead to deadlocks,
in ext4's Asynchronous I/O and online defrag support, thanks to good
work by Dmitry Monakhov.
There are also a large number of more minor bug fixes and cleanups
from a number of other ext4 contributors, quite of few of which have
submitted fixes for the first time.
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Merge tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 updates from Ted Ts'o:
"The big new feature added this time is supporting online resizing
using the meta_bg feature. This allows us to resize file systems
which are greater than 16TB. In addition, the speed of online
resizing has been improved in general.
We also fix a number of races, some of which could lead to deadlocks,
in ext4's Asynchronous I/O and online defrag support, thanks to good
work by Dmitry Monakhov.
There are also a large number of more minor bug fixes and cleanups
from a number of other ext4 contributors, quite of few of which have
submitted fixes for the first time."
* tag 'ext4_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: (69 commits)
ext4: fix ext4_flush_completed_IO wait semantics
ext4: fix mtime update in nodelalloc mode
ext4: fix ext_remove_space for punch_hole case
ext4: punch_hole should wait for DIO writers
ext4: serialize truncate with owerwrite DIO workers
ext4: endless truncate due to nonlocked dio readers
ext4: serialize unlocked dio reads with truncate
ext4: serialize dio nonlocked reads with defrag workers
ext4: completed_io locking cleanup
ext4: fix unwritten counter leakage
ext4: give i_aiodio_unwritten a more appropriate name
ext4: ext4_inode_info diet
ext4: convert to use leXX_add_cpu()
ext4: ext4_bread usage audit
fs: reserve fallocate flag codepoint
ext4: remove redundant offset check in mext_check_arguments()
ext4: don't clear orphan list on ro mount with errors
jbd2: fix assertion failure in commit code due to lacking transaction credits
ext4: release donor reference when EXT4_IOC_MOVE_EXT ioctl fails
ext4: enable FITRIM ioctl on bigalloc file system
...
Pull the trivial tree from Jiri Kosina:
"Tiny usual fixes all over the place"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (34 commits)
doc: fix old config name of kprobetrace
fs/fs-writeback.c: cleanup riteback_sb_inodes kerneldoc
btrfs: fix the commment for the action flags in delayed-ref.h
btrfs: fix trivial typo for the comment of BTRFS_FREE_INO_OBJECTID
vfs: fix kerneldoc for generic_fh_to_parent()
treewide: fix comment/printk/variable typos
ipr: fix small coding style issues
doc: fix broken utf8 encoding
nfs: comment fix
platform/x86: fix asus_laptop.wled_type module parameter
mfd: printk/comment fixes
doc: getdelays.c: remember to close() socket on error in create_nl_socket()
doc: aliasing-test: close fd on write error
mmc: fix comment typos
dma: fix comments
spi: fix comment/printk typos in spi
Coccinelle: fix typo in memdup_user.cocci
tmiofb: missing NULL pointer checks
tools: perf: Fix typo in tools/perf
tools/testing: fix comment / output typos
...
In ext4_nonda_switch(), if the file system is getting full we used to
call writeback_inodes_sb_if_idle(). The problem is that we can be
holding i_mutex already, and this causes a potential deadlock when
writeback_inodes_sb_if_idle() when it tries to take s_umount. (See
lockdep output below).
As it turns out we don't need need to hold s_umount; the fact that we
are in the middle of the write(2) system call will keep the superblock
pinned. Unfortunately writeback_inodes_sb() checks to make sure
s_umount is taken, and the VFS uses a different mechanism for making
sure the file system doesn't get unmounted out from under us. The
simplest way of dealing with this is to just simply grab s_umount
using a trylock, and skip kicking the writeback flusher thread in the
very unlikely case that we can't take a read lock on s_umount without
blocking.
Also, we now check the cirteria for kicking the writeback thread
before we decide to whether to fall back to non-delayed writeback, so
if there are any outstanding delayed allocation writes, we try to get
them resolved as soon as possible.
[ INFO: possible circular locking dependency detected ]
3.6.0-rc1-00042-gce894ca #367 Not tainted
-------------------------------------------------------
dd/8298 is trying to acquire lock:
(&type->s_umount_key#18){++++..}, at: [<c02277d4>] writeback_inodes_sb_if_idle+0x28/0x46
but task is already holding lock:
(&sb->s_type->i_mutex_key#8){+.+...}, at: [<c01ddcce>] generic_file_aio_write+0x5f/0xd3
which lock already depends on the new lock.
2 locks held by dd/8298:
#0: (sb_writers#2){.+.+.+}, at: [<c01ddcc5>] generic_file_aio_write+0x56/0xd3
#1: (&sb->s_type->i_mutex_key#8){+.+...}, at: [<c01ddcce>] generic_file_aio_write+0x5f/0xd3
stack backtrace:
Pid: 8298, comm: dd Not tainted 3.6.0-rc1-00042-gce894ca #367
Call Trace:
[<c015b79c>] ? console_unlock+0x345/0x372
[<c06d62a1>] print_circular_bug+0x190/0x19d
[<c019906c>] __lock_acquire+0x86d/0xb6c
[<c01999db>] ? mark_held_locks+0x5c/0x7b
[<c0199724>] lock_acquire+0x66/0xb9
[<c02277d4>] ? writeback_inodes_sb_if_idle+0x28/0x46
[<c06db935>] down_read+0x28/0x58
[<c02277d4>] ? writeback_inodes_sb_if_idle+0x28/0x46
[<c02277d4>] writeback_inodes_sb_if_idle+0x28/0x46
[<c026f3b2>] ext4_nonda_switch+0xe1/0xf4
[<c0271ece>] ext4_da_write_begin+0x27/0x193
[<c01dcdb0>] generic_file_buffered_write+0xc8/0x1bb
[<c01ddc47>] __generic_file_aio_write+0x1dd/0x205
[<c01ddce7>] generic_file_aio_write+0x78/0xd3
[<c026d336>] ext4_file_write+0x480/0x4a6
[<c0198c1d>] ? __lock_acquire+0x41e/0xb6c
[<c0180944>] ? sched_clock_cpu+0x11a/0x13e
[<c01967e9>] ? trace_hardirqs_off+0xb/0xd
[<c018099f>] ? local_clock+0x37/0x4e
[<c0209f2c>] do_sync_write+0x67/0x9d
[<c0209ec5>] ? wait_on_retry_sync_kiocb+0x44/0x44
[<c020a7b9>] vfs_write+0x7b/0xe6
[<c020a9a6>] sys_write+0x3b/0x64
[<c06dd4bd>] syscall_call+0x7/0xb
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: stable@vger.kernel.org
The function scans @delaying_queue and stops at the first inode
whose dirtied_when is after *work->older_than_this. So the expired
ones being moved are those before *work->older_than_this. Correct
the comment here.
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com>
Since per-BDI flusher threads were introduced in 2.6, the pdflush
mechanism is not used any more. But the old interface exported through
/proc/sys/vm/nr_pdflush_threads still exists and is obviously useless.
For back-compatibility, printk warning information and return 2 to notify
the users that the interface is removed.
Signed-off-by: Wanpeng Li <liwp@linux.vnet.ibm.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
which can adapt equally well to fast/slow devices.
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Merge tag 'writeback-proportions' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
Pull writeback updates from Wu Fengguang:
"Use time based periods to age the writeback proportions, which can
adapt equally well to fast/slow devices."
Fix up trivial conflict in comment in fs/sync.c
* tag 'writeback-proportions' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: Fix some comment errors
block: Convert BDI proportion calculations to flexible proportions
lib: Fix possible deadlock in flexible proportion code
lib: Proportions with flexible period
In principle, a filesystem may want to have ->sync_fs() called during sync(1)
although it does not have a bdi (i.e. s_bdi is set to noop_backing_dev_info).
Only writeback code really needs bdi set to something reasonable. So move the
checks where they are more logical.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Fix bug introduced by 169ebd90. We have to have wb_list_lock locked when
restarting writeback loop after having waited for inode writeback.
Bug description by Ted Tso:
I can reproduce this fairly easily by using ext4 w/o a journal, running
under KVM with 1024megs memory, with fsstress (xfstests #13):
[ 45.153294] =====================================
[ 45.154784] [ BUG: bad unlock balance detected! ]
[ 45.155591] 3.5.0-rc1-00002-gb22b1f1 #124 Not tainted
[ 45.155591] -------------------------------------
[ 45.155591] flush-254:16/2499 is trying to release lock (&(&wb->list_lock)->rlock) at:
[ 45.155591] [<c022c3da>] writeback_sb_inodes+0x160/0x327
[ 45.155591] but there are no more locks to release!
Reported-by: Theodore Ts'o <tytso@mit.edu>
Tested-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Doing iput() from flusher thread (writeback_sb_inodes()) can create problems
because iput() can do a lot of work - for example truncate the inode if it's
the last iput on unlinked file. Some filesystems depend on flusher thread
progressing (e.g. because they need to flush delay allocated blocks to reduce
allocation uncertainty) and so flusher thread doing truncate creates
interesting dependencies and possibilities for deadlocks.
We get rid of iput() in flusher thread by using the fact that I_SYNC inode
flag effectively pins the inode in memory. So if we take care to either hold
i_lock or have I_SYNC set, we can get away without taking inode reference
in writeback_sb_inodes().
As a side effect of these changes, we also fix possible use-after-free in
wb_writeback() because inode_wait_for_writeback() call could try to reacquire
i_lock on the inode that was already free.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
The code in writeback_single_inode() is relatively complex. The list requeing
logic makes sense only for flusher thread but not really for sync_inode() or
write_inode_now() callers. Also when we want to get rid of inode references
held by flusher thread, we will need a special I_SYNC handling there.
So separate part of writeback_single_inode() which does the real writeback work
into __writeback_single_inode() and make writeback_single_inode() do only stuff
necessary for callers writing only one inode, moving the special list handling
into writeback_sb_inodes(). As a sideeffect this fixes a possible race where we
could skip some inode during sync(2) because other writer refiled it from b_io
to b_dirty list. Also I_SYNC handling is moved into the callers of
__writeback_single_inode() to make locking easier.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
writeback_single_inode() doesn't need wb->list_lock for anything on entry now.
So remove the requirement. This makes locking of writeback_single_inode()
temporarily awkward (entering with i_lock, returning with i_lock and
wb->list_lock) but it will be sanitized in the next patch.
Also inode_wait_for_writeback() doesn't need wb->list_lock for anything. It was
just taking it to make usage convenient for callers but with
writeback_single_inode() changing it's not very convenient anymore. So remove
the lock from that function.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Move inode requeueing after inode has been written out into a separate
function.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Instead of clearing I_DIRTY_PAGES and resetting it when we didn't succeed in
writing them all, just clear the bit only when we succeeded writing all the
pages. We also move the clearing of the bit close to other i_state handling to
separate it from writeback list handling. This is desirable because list
handling will differ for flusher thread and other writeback_single_inode()
callers in future. No filesystem plays any tricks with I_DIRTY_PAGES (like
checking it in ->writepages or ->write_inode implementation) so this movement
is safe.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
When writeback_single_inode() is called on inode which has I_SYNC already
set while doing WB_SYNC_NONE, inode is moved to b_more_io list. However
this makes sense only if the caller is flusher thread. For other callers of
writeback_single_inode() it doesn't really make sense and may be even wrong
- flusher thread may be doing WB_SYNC_ALL writeback in parallel.
So we move requeueing from writeback_single_inode() to writeback_sb_inodes().
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Move clearing of I_SYNC into inode_sync_complete(). It is more logical to have
clearing of I_SYNC bit and waking of waiters in one place. Also later we will
have two places needing to clear I_SYNC and wake up waiters so this allows them
to use the common helper. Moving of I_SYNC clearing to a later stage of
writeback_single_inode() is safe since we hold i_lock all the time.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
"[PATCH 0/3] RFC - module.h usage cleanups in fs/ and lib/"
https://lkml.org/lkml/2012/2/29/589
--
Fix up files in fs/ and lib/ dirs to only use module.h if they really
need it.
These are trivial in scope vs. the work done previously. We now have
things where any few remaining cleanups can be farmed out to arch or
subsystem maintainers, and I have done so when possible. What is
remaining here represents the bits that don't clearly lie within a
single arch/subsystem boundary, like the fs dir and the lib dir.
Some duplicate includes arising from overlapping fixes from
independent subsystem maintainer submissions are also quashed.
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Merge tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux
Pull cleanup of fs/ and lib/ users of module.h from Paul Gortmaker:
"Fix up files in fs/ and lib/ dirs to only use module.h if they really
need it.
These are trivial in scope vs the work done previously. We now have
things where any few remaining cleanups can be farmed out to arch or
subsystem maintainers, and I have done so when possible. What is
remaining here represents the bits that don't clearly lie within a
single arch/subsystem boundary, like the fs dir and the lib dir.
Some duplicate includes arising from overlapping fixes from
independent subsystem maintainer submissions are also quashed."
Fix up trivial conflicts due to clashes with other include file cleanups
(including some due to the previous bug.h cleanup pull).
* tag 'module-for-3.4' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux:
lib: reduce the use of module.h wherever possible
fs: reduce the use of module.h wherever possible
includecheck: delete any duplicate instances of module.h
The comment is hopelessly outdated and misplaced. We no longer have 'bdi'
part of writeback work, the comment about blockdev super is outdated,
comment about throttling as well. Information about list handling is in
more detail at queue_io(). So just move the bit about older_than_this to
close to move_expired_inodes() and remove the rest.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
inode_sync_wait() in write_inode_now() is just bogus. That function waits for
I_SYNC bit to be cleared but writeback_single_inode() clears the bit on return
so the wait is effectivelly a nop unless someone else submits the inode for
writeback again. All the waiting write_inode_now() needs is achieved by using
WB_SYNC_ALL writeback mode.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Pull trivial tree from Jiri Kosina:
"It's indeed trivial -- mostly documentation updates and a bunch of
typo fixes from Masanari.
There are also several linux/version.h include removals from Jesper."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (101 commits)
kcore: fix spelling in read_kcore() comment
constify struct pci_dev * in obvious cases
Revert "char: Fix typo in viotape.c"
init: fix wording error in mm_init comment
usb: gadget: Kconfig: fix typo for 'different'
Revert "power, max8998: Include linux/module.h just once in drivers/power/max8998_charger.c"
writeback: fix fn name in writeback_inodes_sb_nr_if_idle() comment header
writeback: fix typo in the writeback_control comment
Documentation: Fix multiple typo in Documentation
tpm_tis: fix tis_lock with respect to RCU
Revert "media: Fix typo in mixer_drv.c and hdmi_drv.c"
Doc: Update numastat.txt
qla4xxx: Add missing spaces to error messages
compiler.h: Fix typo
security: struct security_operations kerneldoc fix
Documentation: broken URL in libata.tmpl
Documentation: broken URL in filesystems.tmpl
mtd: simplify return logic in do_map_probe()
mm: fix comment typo of truncate_inode_pages_range
power: bq27x00: Fix typos in comment
...
For files only using THIS_MODULE and/or EXPORT_SYMBOL, map
them onto including export.h -- or if the file isn't even
using those, then just delete the include. Fix up any implicit
include dependencies that were being masked by module.h along
the way.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
bdi_prune_sb() resets sb->s_bdi to default_backing_dev_info when the
tearing down the original bdi. Fix trace_writeback_single_inode to
use sb->s_bdi=default_backing_dev_info rather than bdi->dev=NULL for a
teared down bdi.
Cc: <stable@kernel.org>
Reported-by: Rabin Vincent <rabin@rab.in>
Tested-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
* 'pm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (76 commits)
PM / Hibernate: Implement compat_ioctl for /dev/snapshot
PM / Freezer: fix return value of freezable_schedule_timeout_killable()
PM / shmobile: Allow the A4R domain to be turned off at run time
PM / input / touchscreen: Make st1232 use device PM QoS constraints
PM / QoS: Introduce dev_pm_qos_add_ancestor_request()
PM / shmobile: Remove the stay_on flag from SH7372's PM domains
PM / shmobile: Don't include SH7372's INTCS in syscore suspend/resume
PM / shmobile: Add support for the sh7372 A4S power domain / sleep mode
PM: Drop generic_subsys_pm_ops
PM / Sleep: Remove forward-only callbacks from AMBA bus type
PM / Sleep: Remove forward-only callbacks from platform bus type
PM: Run the driver callback directly if the subsystem one is not there
PM / Sleep: Make pm_op() and pm_noirq_op() return callback pointers
PM/Devfreq: Add Exynos4-bus device DVFS driver for Exynos4210/4212/4412.
PM / Sleep: Merge internal functions in generic_ops.c
PM / Sleep: Simplify generic system suspend callbacks
PM / Hibernate: Remove deprecated hibernation snapshot ioctls
PM / Sleep: Fix freezer failures due to racy usermodehelper_is_disabled()
ARM: S3C64XX: Implement basic power domain support
PM / shmobile: Use common always on power domain governor
...
Fix up trivial conflict in fs/xfs/xfs_buf.c due to removal of unused
XBT_FORCE_SLEEP bit
Fix compile error
fs/fs-writeback.c:515:33: error: ‘PAGE_CACHE_SHIFT’ undeclared (first use in this function)
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Move invalidate_bdev, block_sync_page into fs/block_dev.c. Export
kill_bdev as well, so brd doesn't have to open code it. Reduce
buffer_head.h requirement accordingly.
Removed a rather large comment from invalidate_bdev, as it looked a bit
obsolete to bother moving. The small comment replacing it says enough.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* pm-sleep: (51 commits)
PM: Drop generic_subsys_pm_ops
PM / Sleep: Remove forward-only callbacks from AMBA bus type
PM / Sleep: Remove forward-only callbacks from platform bus type
PM: Run the driver callback directly if the subsystem one is not there
PM / Sleep: Make pm_op() and pm_noirq_op() return callback pointers
PM / Sleep: Merge internal functions in generic_ops.c
PM / Sleep: Simplify generic system suspend callbacks
PM / Hibernate: Remove deprecated hibernation snapshot ioctls
PM / Sleep: Fix freezer failures due to racy usermodehelper_is_disabled()
PM / Sleep: Recommend [un]lock_system_sleep() over using pm_mutex directly
PM / Sleep: Replace mutex_[un]lock(&pm_mutex) with [un]lock_system_sleep()
PM / Sleep: Make [un]lock_system_sleep() generic
PM / Sleep: Use the freezer_count() functions in [un]lock_system_sleep() APIs
PM / Freezer: Remove the "userspace only" constraint from freezer[_do_not]_count()
PM / Hibernate: Replace unintuitive 'if' condition in kernel/power/user.c with 'else'
Freezer / sunrpc / NFS: don't allow TASK_KILLABLE sleeps to block the freezer
PM / Sleep: Unify diagnostic messages from device suspend/resume
ACPI / PM: Do not save/restore NVS on Asus K54C/K54HR
PM / Hibernate: Remove deprecated hibernation test modes
PM / Hibernate: Thaw processes in SNAPSHOT_CREATE_IMAGE ioctl test path
...
Conflicts:
kernel/kmod.c
* master: (848 commits)
SELinux: Fix RCU deref check warning in sel_netport_insert()
binary_sysctl(): fix memory leak
mm/vmalloc.c: remove static declaration of va from __get_vm_area_node
ipmi_watchdog: restore settings when BMC reset
oom: fix integer overflow of points in oom_badness
memcg: keep root group unchanged if creation fails
nilfs2: potential integer overflow in nilfs_ioctl_clean_segments()
nilfs2: unbreak compat ioctl
cpusets: stall when updating mems_allowed for mempolicy or disjoint nodemask
evm: prevent racing during tfm allocation
evm: key must be set once during initialization
mmc: vub300: fix type of firmware_rom_wait_states module parameter
Revert "mmc: enable runtime PM by default"
mmc: sdhci: remove "state" argument from sdhci_suspend_host
x86, dumpstack: Fix code bytes breakage due to missing KERN_CONT
IB/qib: Correct sense on freectxts increment and decrement
RDMA/cma: Verify private data length
cgroups: fix a css_set not found bug in cgroup_attach_proc
oprofile: Fix uninitialized memory access when writing to writing to oprofilefs
Revert "xen/pv-on-hvm kexec: add xs_reset_watches to shutdown watches from old kernel"
...
Conflicts:
kernel/cgroup_freezer.c
Current livelock avoidance code makes background work to include only inodes
that were dirtied before background writeback has started. However background
writeback can be running for a long time and thus excluding newly dirtied
inodes can eventually exclude significant portion of dirty inodes making
background writeback inefficient. Since background writeback avoids livelocking
the flusher thread by yielding to any other work, there is no real reason why
background work should not include all dirty inodes so change the logic in
wb_writeback().
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
This makes the binary trace understandable by trace-cmd.
CC: Dave Chinner <david@fromorbit.com>
CC: Curt Wohlgemuth <curtw@google.com>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Document the @reason parameter to make "make htmldocs" happy.
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Marcos Paulo de Souza <marcos.mage@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Writeback and thinkpad_acpi have been using thaw_process() to prevent
deadlock between the freezer and kthread_stop(); unfortunately, this
is inherently racy - nothing prevents freezing from happening between
thaw_process() and kthread_stop().
This patch implements kthread_freezable_should_stop() which enters
refrigerator if necessary but is guaranteed to return if
kthread_stop() is invoked. Both thaw_process() users are converted to
use the new function.
Note that this deadlock condition exists for many of freezable
kthreads. They need to be converted to use the new should_stop or
freezable workqueue.
Tested with synthetic test case.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Henrique de Moraes Holschuh <ibm-acpi@hmh.eng.br>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
This creates a new 'reason' field in a wb_writeback_work
structure, which unambiguously identifies who initiates
writeback activity. A 'wb_reason' enumeration has been
added to writeback.h, to enumerate the possible reasons.
The 'writeback_work_class' and tracepoint event class and
'writeback_queue_io' tracepoints are updated to include the
symbolic 'reason' in all trace events.
And the 'writeback_inodes_sbXXX' family of routines has had
a wb_stats parameter added to them, so callers can specify
why writeback is being started.
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Instead of sending ->older_than_this to queue_io() and
move_expired_inodes(), send the entire wb_writeback_work
structure. There are other fields of a work item that are
useful in these routines and in tracepoints.
Acked-by: Jan Kara <jack@suse.cz>
Signed-off-by: Curt Wohlgemuth <curtw@google.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
One thing puzzled me is that in JBOD case, the per-disk writeout
performance is smaller than the corresponding single-disk case even
when they have comparable bdi_thresh. Tracing shows find that in single
disk case, bdi_writeback is always kept high while in JBOD case, it
could drop low from time to time and correspondingly bdi_reclaimable
could sometimes rush high.
The fix is to watch bdi_reclaimable and kick background writeback as
soon as it goes high. This resembles the global background threshold
but in per-bdi manner. The trick is, as long as bdi_reclaimable does
not go high, bdi_writeback naturally won't go low because
bdi_reclaimable+bdi_writeback ~= bdi_thresh.
With less fluctuated writeback pages, JBOD performance is observed to
increase noticeably in various cases.
vmstat:nr_written values before/after patch:
3.1.0-rc4-wo-underrun+ 3.1.0-rc4-bgthresh3+
------------------------ ------------------------
125596480 +25.9% 158179363 JBOD-10HDD-16G/ext4-100dd-1M-24p-16384M-20:10-X
61790815 +110.4% 130032231 JBOD-10HDD-16G/ext4-10dd-1M-24p-16384M-20:10-X
58853546 -0.1% 58823828 JBOD-10HDD-16G/ext4-1dd-1M-24p-16384M-20:10-X
110159811 +24.7% 137355377 JBOD-10HDD-16G/xfs-100dd-1M-24p-16384M-20:10-X
69544762 +10.8% 77080047 JBOD-10HDD-16G/xfs-10dd-1M-24p-16384M-20:10-X
50644862 +0.5% 50890006 JBOD-10HDD-16G/xfs-1dd-1M-24p-16384M-20:10-X
42677090 +28.0% 54643527 JBOD-10HDD-thresh=100M/ext4-100dd-1M-24p-16384M-100M:10-X
47491324 +13.3% 53785605 JBOD-10HDD-thresh=100M/ext4-10dd-1M-24p-16384M-100M:10-X
52548986 +0.9% 53001031 JBOD-10HDD-thresh=100M/ext4-1dd-1M-24p-16384M-100M:10-X
26783091 +36.8% 36650248 JBOD-10HDD-thresh=100M/xfs-100dd-1M-24p-16384M-100M:10-X
35526347 +14.0% 40492312 JBOD-10HDD-thresh=100M/xfs-10dd-1M-24p-16384M-100M:10-X
44670723 -1.1% 44177606 JBOD-10HDD-thresh=100M/xfs-1dd-1M-24p-16384M-100M:10-X
127996037 +22.4% 156719990 JBOD-10HDD-thresh=2G/ext4-100dd-1M-24p-16384M-2048M:10-X
57518856 +3.8% 59677625 JBOD-10HDD-thresh=2G/ext4-10dd-1M-24p-16384M-2048M:10-X
51919909 +12.2% 58269894 JBOD-10HDD-thresh=2G/ext4-1dd-1M-24p-16384M-2048M:10-X
86410514 +79.0% 154660433 JBOD-10HDD-thresh=2G/xfs-100dd-1M-24p-16384M-2048M:10-X
40132519 +38.6% 55617893 JBOD-10HDD-thresh=2G/xfs-10dd-1M-24p-16384M-2048M:10-X
48423248 +7.5% 52042927 JBOD-10HDD-thresh=2G/xfs-1dd-1M-24p-16384M-2048M:10-X
206041046 +44.1% 296846536 JBOD-10HDD-thresh=4G/xfs-100dd-1M-24p-16384M-4096M:10-X
72312903 -19.4% 58272885 JBOD-10HDD-thresh=4G/xfs-10dd-1M-24p-16384M-4096M:10-X
50635672 -0.5% 50384787 JBOD-10HDD-thresh=4G/xfs-1dd-1M-24p-16384M-4096M:10-X
68308534 +115.7% 147324758 JBOD-10HDD-thresh=800M/ext4-100dd-1M-24p-16384M-800M:10-X
57882933 +14.5% 66269621 JBOD-10HDD-thresh=800M/ext4-10dd-1M-24p-16384M-800M:10-X
52183472 +12.8% 58855181 JBOD-10HDD-thresh=800M/ext4-1dd-1M-24p-16384M-800M:10-X
53788956 +94.2% 104460352 JBOD-10HDD-thresh=800M/xfs-100dd-1M-24p-16384M-800M:10-X
44493342 +35.5% 60298210 JBOD-10HDD-thresh=800M/xfs-10dd-1M-24p-16384M-800M:10-X
42641209 +18.9% 50681038 JBOD-10HDD-thresh=800M/xfs-1dd-1M-24p-16384M-800M:10-X
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
