kernel_optimize_test/fs
Tejun Heo 839a8e8660 writeback: replace custom worker pool implementation with unbound workqueue
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>
2013-04-01 19:08:06 -07:00
..
9p fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
adfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
affs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
afs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
autofs4 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
befs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
bfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2013-03-29 11:13:25 -07:00
cachefiles
ceph fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
cifs Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6 2013-03-21 17:59:22 -07:00
coda fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
configfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
cramfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
debugfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
devpts fs: Limit sys_mount to only request filesystem modules (Part 2). 2013-03-07 01:08:55 -08:00
dlm hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
ecryptfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-03-09 16:51:13 -08:00
efs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
exofs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
exportfs hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
ext2 ext2: Fix BUG_ON in evict() on inode deletion 2013-03-13 15:23:44 +01:00
ext3 ext3: Fix format string issues 2013-03-11 22:05:56 +01:00
ext4 Fix a number of regression and other bugs in ext4, most of which were 2013-03-21 17:56:10 -07:00
f2fs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
fat fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
freevxfs fs: Readd the fs module aliases. 2013-03-12 18:55:21 -07:00
fscache hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
fuse fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
gfs2 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
hfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
hfsplus fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
hostfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-03-13 15:47:50 -07:00
hpfs fs: Limit sys_mount to only request filesystem modules. (Part 3) 2013-03-11 07:09:48 -07:00
hppfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
hugetlbfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
isofs fs: Readd the fs module aliases. 2013-03-12 18:55:21 -07:00
jbd
jbd2 jbd2: fix use after free in jbd2_journal_dirty_metadata() 2013-03-11 13:24:56 -04:00
jffs2 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
jfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
lockd Merge branch 'for-3.9' of git://linux-nfs.org/~bfields/linux 2013-02-28 18:02:55 -08:00
logfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
minix fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
ncpfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
nfs NFS client bugfixes for Linux 3.9 2013-03-26 14:23:45 -07:00
nfs_common nfs_common: Update the translation between nfsv3 acls linux posix acls 2013-02-13 06:15:14 -08:00
nfsd nfsd: fix bad offset use 2013-03-22 16:55:15 -04:00
nilfs2 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
nls
notify hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
ntfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
ocfs2 fs: Limit sys_mount to only request filesystem modules (Part 2). 2013-03-07 01:08:55 -08:00
omfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
openpromfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
proc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace 2013-03-28 13:43:46 -07:00
pstore A few fixes to reduce places where pstore might hang 2013-02-21 09:38:18 -08:00
qnx4 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
qnx6 fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
quota quota: add missing use of dq_data_lock in __dquot_initialize 2013-03-11 22:05:56 +01:00
ramfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
reiserfs reiserfs: Use kstrdup instead of kmalloc/strcpy 2013-03-11 22:05:57 +01:00
romfs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
squashfs fs: Limit sys_mount to only request filesystem modules. (Part 3) 2013-03-11 07:09:48 -07:00
sysfs sysfs fixes for 3.9-rc4 2013-03-28 15:52:14 -07:00
sysv fs: Readd the fs module aliases. 2013-03-12 18:55:21 -07:00
ubifs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
udf fs: Limit sys_mount to only request filesystem modules. (Part 3) 2013-03-11 07:09:48 -07:00
ufs fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
xfs - Fix for a potential infinite loop which was introduced in 4d559a3bcb 2013-03-19 15:17:40 -07:00
aio.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
anon_inodes.c get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero 2013-02-26 02:46:11 -05:00
attr.c
bad_inode.c
binfmt_aout.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
binfmt_elf_fdpic.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-02-26 20:16:07 -08:00
binfmt_elf.c ImgTec Meta architecture changes for v3.9-rc1 2013-03-03 12:06:09 -08:00
binfmt_em86.c
binfmt_flat.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
binfmt_misc.c fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
binfmt_script.c
binfmt_som.c
bio-integrity.c
bio.c
block_dev.c Merge branch 'for-3.9/core' of git://git.kernel.dk/linux-block 2013-02-28 12:52:24 -08:00
buffer.c Merge branch 'for-3.9/core' of git://git.kernel.dk/linux-block 2013-02-28 12:52:24 -08:00
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
compat.c Fix: compat_rw_copy_check_uvector() misuse in aio, readv, writev, and security keys 2013-03-12 11:05:45 -07:00
coredump.c coredump: remove redundant defines for dumpable states 2013-02-27 19:10:11 -08:00
coredump.h
dcache.c Nest rename_lock inside vfsmount_lock 2013-03-26 18:25:57 -04:00
dcookies.c
direct-io.c fs: Fix possible use-after-free with AIO 2013-02-22 23:31:36 -05:00
drop_caches.c
eventfd.c
eventpoll.c
exec.c coredump: remove redundant defines for dumpable states 2013-02-27 19:10:11 -08:00
fcntl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
fhandle.c
fifo.c
file_table.c cache the value of file_inode() in struct file 2013-03-01 19:48:30 -05:00
file.c locking: Various static lock initializer fixes 2013-02-19 08:42:45 +01:00
filesystems.c fs: Limit sys_mount to only request filesystem modules. 2013-03-03 19:36:31 -08:00
fs_struct.c constify path_get/path_put and fs_struct.c stuff 2013-03-01 23:51:07 -05:00
fs-writeback.c writeback: replace custom worker pool implementation with unbound workqueue 2013-04-01 19:08:06 -07:00
generic_acl.c
inode.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
internal.h Don't bother with redoing rw_verify_area() from default_file_splice_from() 2013-03-21 13:11:11 -04:00
ioctl.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
ioprio.c
Kconfig
Kconfig.binfmt
libfs.c
locks.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
Makefile
mbcache.c
mount.h
mpage.c
namei.c vfs: don't BUG_ON() if following a /proc fd pseudo-symlink results in a symlink 2013-03-08 09:03:07 -08:00
namespace.c userns: Restrict when proc and sysfs can be mounted 2013-03-27 07:50:08 -07:00
no-block.c
open.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-03-03 13:23:03 -08:00
pipe.c vfs: fix pipe counter breakage 2013-03-12 08:29:17 -07:00
pnode.c vfs: Carefully propogate mounts across user namespaces 2013-03-27 07:50:05 -07:00
pnode.h vfs: Carefully propogate mounts across user namespaces 2013-03-27 07:50:05 -07:00
posix_acl.c
proc_namespace.c
read_write.c vfs/splice: Fix missed checks in new __kernel_write() helper 2013-03-27 09:24:02 -07:00
read_write.h
readdir.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
select.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
seq_file.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2013-03-03 13:23:03 -08:00
signalfd.c
splice.c Don't bother with redoing rw_verify_area() from default_file_splice_from() 2013-03-21 13:11:11 -04:00
stack.c
stat.c switch vfs_getattr() to struct path 2013-02-26 02:46:08 -05:00
statfs.c
super.c hlist: drop the node parameter from iterators 2013-02-27 19:10:24 -08:00
sync.c new helper: file_inode(file) 2013-02-22 23:31:31 -05:00
timerfd.c compat: restore timerfd settime and gettime compat syscalls 2013-03-02 09:35:13 -05:00
utimes.c
xattr_acl.c
xattr.c