remarkable-linux/fs
Dave Chinner 3c35337576 xfs: remove dquot hints
group and project quota hints are currently stored on the user
dquot. If we are attaching quotas to the inode, then the group and
project dquots are stored as hints on the user dquot to save having
to look them up again later.

The thing is, the hints are not used for that inode for the rest of
the life of the inode - the dquots are attached directly to the
inode itself - so the only time the hints are used is when an inode
first has dquots attached.

When the hints on the user dquot don't match the dquots being
attache dto the inode, they are then removed and replaced with the
new hints. If a user is concurrently modifying files in different
group and/or project contexts, then this leads to thrashing of the
hints attached to user dquot.

If user quotas are not enabled, then hints are never even used.

So, if the hints are used to avoid the cost of the lookup, is the
cost of the lookup significant enough to justify the hint
infrstructure? Maybe it was once, when there was a global quota
manager shared between all XFS filesystems and was hash table based.

However, lookups are now much simpler, requiring only a single lock and
radix tree lookup local to the filesystem and no hash or LRU
manipulations to be made. Hence the cost of lookup is much lower
than when hints were implemented. Turns out that benchmarks show
that, too, with thir being no differnce in performance when doing
file creation workloads as a single user with user, group and
project quotas enabled - the hints do not make the code go any
faster. In fact, removing the hints shows a 2-3% reduction in the
time it takes to create 50 million inodes....

So, let's just get rid of the hints and the complexity around them.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
2014-05-05 17:30:15 +10:00
..
9p mm: implement ->map_pages for page cache 2014-04-07 16:35:53 -07:00
adfs fs/adfs/super.c: add __init to init_inodecache() 2014-04-07 16:36:08 -07:00
affs affs: add mount option to avoid filename truncates 2014-04-07 16:36:08 -07:00
afs mm + fs: store shadow entries in page cache 2014-04-03 16:21:01 -07:00
autofs4 autofs4: check dev ioctl size before allocating 2014-04-08 16:48:51 -07:00
befs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
bfs fs/bfs/inode.c: add __init to init_inodecache() 2014-04-07 16:36:08 -07:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
cachefiles Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
ceph ceph: fix pr_fmt() redefinition 2014-04-12 15:39:53 -07:00
cifs cifs: Use min_t() when comparing "size_t" and "unsigned long" 2014-04-13 14:10:26 -07:00
coda Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
configfs
cramfs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
debugfs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
devpts fs: push sync_filesystem() down to the file system's remount_fs() 2014-03-13 10:14:33 -04:00
dlm net: Fix use after free by removing length arg from sk_data_ready callbacks. 2014-04-11 16:15:36 -04:00
ecryptfs Merge branch 'cross-rename' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs 2014-04-04 14:03:05 -07:00
efivarfs
efs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
exofs Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osd 2014-04-10 14:33:02 -07:00
exportfs
ext2 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-04-07 17:59:17 -07:00
ext3 Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-04-07 17:59:17 -07:00
ext4 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
f2fs Merge branch 'akpm' (incoming from Andrew) 2014-04-07 16:38:06 -07:00
fat Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
freevxfs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
fscache
fuse Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
gfs2 mm: implement ->map_pages for page cache 2014-04-07 16:35:53 -07:00
hfs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
hfsplus Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
hostfs mm + fs: store shadow entries in page cache 2014-04-03 16:21:01 -07:00
hpfs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
hppfs
hugetlbfs mm, hugetlb: unify region structure handling 2014-04-03 16:20:59 -07:00
isofs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-04-07 17:59:17 -07:00
jbd
jbd2 jbd2: improve error messages for inconsistent journal heads 2014-03-12 16:38:03 -04:00
jffs2 MTD updates for 3.15: 2014-04-07 10:17:30 -07:00
jfs Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
kernfs Merge branch 'akpm' (incoming from Andrew) 2014-04-03 16:22:16 -07:00
lockd lockd: ensure we tear down any live sockets when socket creation fails during lockd_up 2014-03-28 10:43:08 -04:00
logfs mm + fs: store shadow entries in page cache 2014-04-03 16:21:01 -07:00
minix Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
ncpfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-04-12 17:31:22 -07:00
nfs mm: implement ->map_pages for page cache 2014-04-07 16:35:53 -07:00
nfs_common
nfsd Merge branch 'for-3.15' of git://linux-nfs.org/~bfields/linux 2014-04-08 18:28:14 -07:00
nilfs2 mm: implement ->map_pages for page cache 2014-04-07 16:35:53 -07:00
nls
notify fanotify: move unrelated handling from copy_event_to_user() 2014-04-03 16:20:51 -07:00
ntfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
ocfs2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2014-04-12 17:31:22 -07:00
omfs mm + fs: store shadow entries in page cache 2014-04-03 16:21:01 -07:00
openpromfs fs: push sync_filesystem() down to the file system's remount_fs() 2014-03-13 10:14:33 -04:00
proc Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
pstore Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
qnx4 fs: push sync_filesystem() down to the file system's remount_fs() 2014-03-13 10:14:33 -04:00
qnx6 fs: push sync_filesystem() down to the file system's remount_fs() 2014-03-13 10:14:33 -04:00
quota xfs: fix Q_XQUOTARM ioctl 2014-05-05 17:25:50 +10:00
ramfs
reiserfs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-04-07 17:59:17 -07:00
romfs fs: push sync_filesystem() down to the file system's remount_fs() 2014-03-13 10:14:33 -04:00
squashfs fs: push sync_filesystem() down to the file system's remount_fs() 2014-03-13 10:14:33 -04:00
sysfs Revert "sysfs, driver-core: remove unused {sysfs|device}_schedule_callback_owner()" 2014-03-25 20:54:57 -07:00
sysv Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
ubifs mm: implement ->map_pages for page cache 2014-04-07 16:35:53 -07:00
udf Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
ufs fs/ufs: remove unused ufs_super_block_third pointer 2014-04-07 16:36:16 -07:00
xfs xfs: remove dquot hints 2014-05-05 17:30:15 +10:00
aio.c aio: v4 ensure access to ctx->ring_pages is correctly serialised for migration 2014-03-28 10:14:45 -04:00
anon_inodes.c vfs: Allocate anon_inode_inode in anon_inode_init() 2014-03-27 09:52:54 -07:00
attr.c
bad_inode.c
binfmt_aout.c
binfmt_elf.c exec: kill the unnecessary mm->def_flags setting in load_elf_binary() 2014-04-07 16:35:52 -07:00
binfmt_elf_fdpic.c
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c binfmt_misc: add missing 'break' statement 2014-04-03 16:21:16 -07:00
binfmt_script.c
binfmt_som.c
bio-integrity.c block: Ensure we only enable integrity metadata for reads and writes 2014-04-09 08:00:06 -06:00
bio.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
block_dev.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
buffer.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
char_dev.c
compat.c Merge branch 'locks-3.15' of git://git.samba.org/jlayton/linux 2014-04-04 14:21:20 -07:00
compat_binfmt_elf.c
compat_ioctl.c
coredump.c
dcache.c Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2014-04-08 09:52:16 -07:00
dcookies.c
direct-io.c xfs: update for 3.15-rc1 2014-04-04 15:50:08 -07:00
drop_caches.c drop_caches: add some documentation and info message 2014-04-03 16:21:04 -07:00
eventfd.c
eventpoll.c
exec.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
fcntl.c locks: add new fcntl cmd values for handling file private locks 2014-03-31 08:24:43 -04:00
fhandle.c
file.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
file_table.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
filesystems.c sys_sysfs: Add CONFIG_SYSFS_SYSCALL 2014-04-03 16:21:05 -07:00
fs-writeback.c One of the main highlights this time, is not the patches themselves 2014-04-04 14:49:16 -07:00
fs_struct.c
inode.c Major changes for 3.14 include support for the newly added ZERO_RANGE 2014-04-04 15:39:39 -07:00
internal.h
ioctl.c
ioprio.c
Kconfig
Kconfig.binfmt
libfs.c
locks.c locks: make locks_mandatory_area check for file-private locks 2014-03-31 08:24:43 -04:00
Makefile
mbcache.c ext4: each filesystem creates and uses its own mb_cache 2014-03-18 19:24:49 -04:00
mount.h reduce m_start() cost... 2014-04-01 23:19:09 -04:00
mpage.c
namei.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
namespace.c VFS: Make delayed_free() call free_vfsmnt() 2014-04-01 23:19:18 -04:00
no-block.c
open.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-04-12 14:49:50 -07:00
pipe.c switch pipe_read() to copy_page_to_iter() 2014-04-01 23:19:22 -04:00
pnode.c smarter propagate_mnt() 2014-04-01 23:19:08 -04:00
pnode.h smarter propagate_mnt() 2014-04-01 23:19:08 -04:00
posix_acl.c One of the main highlights this time, is not the patches themselves 2014-04-04 14:49:16 -07:00
proc_namespace.c reduce m_start() cost... 2014-04-01 23:19:09 -04:00
read_write.c Merge branch 'compat' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux 2014-03-31 14:32:17 -07:00
readdir.c
select.c
seq_file.c
signalfd.c
splice.c switch vmsplice_to_user() to copy_page_to_iter() 2014-04-01 23:19:23 -04:00
stack.c
stat.c
statfs.c
super.c fs: push sync_filesystem() down to the file system's remount_fs() 2014-03-13 10:14:33 -04:00
sync.c
timerfd.c
utimes.c
xattr.c