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9226b5b440
kernel_optimize_test/fs
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Linus Torvalds 9226b5b440 vfs: avoid non-forwarding large load after small store in path lookup 
The performance regression that Josef Bacik reported in the pathname
lookup (see commit 99d263d4c5 "vfs: fix bad hashing of dentries") made
me look at performance stability of the dcache code, just to verify that
the problem was actually fixed.  That turned up a few other problems in
this area.

There are a few cases where we exit RCU lookup mode and go to the slow
serializing case when we shouldn't, Al has fixed those and they'll come
in with the next VFS pull.

But my performance verification also shows that link_path_walk() turns
out to have a very unfortunate 32-bit store of the length and hash of
the name we look up, followed by a 64-bit read of the combined hash_len
field.  That screws up the processor store to load forwarding, causing
an unnecessary hickup in this critical routine.

It's caused by the ugly calling convention for the "hash_name()"
function, and easily fixed by just making hash_name() fill in the whole
'struct qstr' rather than passing it a pointer to just the hash value.

With that, the profile for this function looks much smoother.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-09-14 17:28:32 -07:00
..
9p Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
adfs adfs: add __printf verification, fix format/argument mismatches 2014-08-08 15:57:24 -07:00
affs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
afs AFS: Correctly assemble the client UUID 2014-07-29 10:14:36 -07:00
autofs4 autofs4: comment typo: remove a a doubled word 2014-08-08 15:57:19 -07:00
befs fs/befs/linuxvfs.c: check superblock before dump operation 2014-08-08 15:57:20 -07:00
bfs fs/bfs: use bfs prefix for dump_imap 2014-08-08 15:57:24 -07:00
btrfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2014-09-12 11:53:30 -07:00
cachefiles fs/cachefiles: replace kerror by pr_err 2014-06-06 16:08:14 -07:00
ceph Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client 2014-08-13 17:43:29 -06:00
cifs Clarify Kconfig help text for CIFS and SMB2/SMB3 2014-08-25 17:01:05 -05:00
coda fs/coda: use linux/uaccess.h 2014-08-08 15:57:20 -07:00
configfs fs/configfs: use pr_fmt 2014-06-04 16:53:53 -07:00
cramfs fs/cramfs/inode.c: use linux/uaccess.h 2014-08-08 15:57:25 -07:00
debugfs fs: debugfs: remove trailing whitespace 2014-07-09 16:58:21 -07:00
devpts fs/devpts/inode.c: convert printk to pr_foo() 2014-06-06 16:08:14 -07:00
dlm fs/dlm/debug_fs.c: remove unnecessary null test before debugfs_remove 2014-08-08 15:57:27 -07:00
ecryptfs write_iter variants of {__,}generic_file_aio_write() 2014-05-06 17:38:00 -04:00
efivarfs fs/efivarfs/super.c: use static const for dentry_operations 2014-06-04 16:54:14 -07:00
efs fs/efs/namei.c: return is not a function 2014-08-08 15:57:18 -07:00
exofs fs/exofs/ore_raid.c: replace count*size kzalloc by kcalloc 2014-08-08 15:57:24 -07:00
exportfs fs/exportfs/expfs.c: kernel-doc warning fixes 2014-06-04 16:54:14 -07:00
ext2 fs/ext2/super.c: Drop memory allocation cast 2014-07-15 22:40:22 +02:00
ext3 ext3: Count internal journal as bsddf overhead in ext3_statfs 2014-08-19 23:16:51 +02:00
ext4 ext4: avoid trying to kfree an ERR_PTR pointer 2014-09-03 09:37:30 -04:00
f2fs f2fs: reposition unlock_new_inode to prevent accessing invalid inode 2014-09-02 00:22:24 -07:00
fat Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
freevxfs
fscache fs/fscache: make ctl_table static 2014-08-06 18:01:12 -07:00
fuse switch iov_iter_get_pages() to passing maximal number of pages 2014-08-07 14:40:11 -04:00
gfs2 Merge branch 'sched/urgent' into sched/core, to merge fixes before applying new changes 2014-07-28 10:03:00 +02:00
hfs write_iter variants of {__,}generic_file_aio_write() 2014-05-06 17:38:00 -04:00
hfsplus Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
hostfs hostfs: support rename flags 2014-08-07 14:40:09 -04:00
hpfs fs/hpfs/dnode.c: fix suspect code indent 2014-08-08 15:57:22 -07:00
hppfs
hugetlbfs fs/hugetlbfs/inode.c: remove null test before kfree 2014-06-04 16:54:11 -07:00
isofs isofs: Fix unbounded recursion when processing relocated directories 2014-08-19 18:29:30 +02:00
jbd fs/jbd/revoke.c: replace shift loop by ilog2 2014-05-21 10:26:13 +02:00
jbd2 jbd2: fix descriptor block size handling errors with journal_csum 2014-08-28 22:22:29 -04:00
jffs2 MTD updates for 3.17-rc1 2014-08-08 18:13:21 -07:00
jfs Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
kernfs Merge 3.16-rc6 into driver-core-next 2014-07-21 10:07:25 -07:00
lockd lockd: fix rpcbind crash on lockd startup failure 2014-09-08 12:03:32 -04:00
logfs fs/logfs/readwrite.c: kernel-doc warning fixes 2014-08-06 18:01:12 -07:00
minix minix zmap block counts calculation fix 2014-08-08 15:57:20 -07:00
ncpfs fs/ncpfs/getopt.c: replace simple_strtoul by kstrtoul 2014-06-04 16:54:21 -07:00
nfs pnfs: fix filelayout_retry_commit when idx > 0 2014-09-10 12:43:45 -07:00
nfs_common fs/nfs_common/nfsacl.c: move EXPORT symbol after functions 2014-07-12 18:43:42 -04:00
nfsd nfsd4: fix rd_dircount enforcement 2014-09-08 12:02:03 -04:00
nilfs2 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-08-11 11:44:11 -07:00
nls
notify fs/notify: don't show f_handle if exportfs_encode_inode_fh failed 2014-09-10 15:42:12 -07:00
ntfs ntfs: kernel-doc warning fixes 2014-08-06 18:01:12 -07:00
ocfs2 ocfs2: quorum: add a log for node not fenced 2014-08-29 16:28:17 -07:00
omfs fs/omfs/inode.c: replace count*size kzalloc by kcalloc 2014-08-08 15:57:25 -07:00
openpromfs
proc Revert "proc: Point /proc/{mounts,net} at /proc/thread-self/{mounts,net} instead of /proc/self/{mounts,net}" 2014-08-10 21:24:59 -07:00
pstore fs/pstore/ram_core.c: replace count*size kmalloc by kmalloc_array 2014-08-08 15:57:25 -07:00
qnx4
qnx6 fs/qnx6: update debugging to current functions 2014-08-08 15:57:26 -07:00
quota fs/quota: kernel-doc warning fixes 2014-07-15 22:40:23 +02:00
ramfs fs/ramfs/file-nommu.c: replace count*size kzalloc by kcalloc 2014-08-08 15:57:18 -07:00
reiserfs Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-08-13 17:45:40 -06:00
romfs fs/romfs/super.c: add blank line after declarations 2014-08-08 15:57:25 -07:00
squashfs fs/squashfs/super.c: logging cleanup 2014-08-06 18:01:13 -07:00
sysfs kernfs: move the last knowledge of sysfs out from kernfs 2014-06-03 08:11:18 -07:00
sysv write_iter variants of {__,}generic_file_aio_write() 2014-05-06 17:38:00 -04:00
ubifs UBIFS: Add log overlap assertions 2014-07-31 15:52:51 +03:00
udf udf: saner calling conventions for udf_new_inode() 2014-09-04 21:37:41 +02:00
ufs ufs: fix deadlocks introduced by sb mutex merge 2014-09-07 13:26:39 -04:00
xfs xfs: trim eofblocks before collapse range 2014-09-02 12:12:53 +10:00
aio.c aio: block exit_aio() until all context requests are completed 2014-09-04 16:54:47 -04:00
anon_inodes.c
attr.c fs,userns: Change inode_capable to capable_wrt_inode_uidgid 2014-06-10 13:57:22 -07:00
bad_inode.c bad_inode: add ->rename2() 2014-08-07 14:40:09 -04:00
binfmt_aout.c
binfmt_elf_fdpic.c
binfmt_elf.c Merge branch 'x86/vdso' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into next 2014-06-05 08:05:29 -07:00
binfmt_em86.c
binfmt_flat.c fs/binfmt_flat.c: make old_reloc() static 2014-06-04 16:54:21 -07:00
binfmt_misc.c
binfmt_script.c
binfmt_som.c
block_dev.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
buffer.c sched: Remove proliferation of wait_on_bit() action functions 2014-07-16 15:10:39 +02:00
char_dev.c
compat_binfmt_elf.c
compat_ioctl.c Bluetooth: Move HCI socket definitions into its own header file 2014-07-11 13:53:04 +03:00
compat.c
coredump.c coredump: fix the setting of PF_DUMPCORE 2014-07-23 15:10:54 -07:00
dcache.c vfs: fix bad hashing of dentries 2014-09-13 11:30:10 -07:00
dcookies.c
direct-io.c switch iov_iter_get_pages() to passing maximal number of pages 2014-08-07 14:40:11 -04:00
drop_caches.c fs: convert use of typedef ctl_table to struct ctl_table 2014-06-06 16:08:16 -07:00
eventfd.c
eventpoll.c eventpoll: fix uninitialized variable in epoll_ctl 2014-09-10 15:42:12 -07:00
exec.c fork/exec: cleanup mm initialization 2014-08-08 15:57:23 -07:00
fcntl.c shm: add sealing API 2014-08-08 15:57:31 -07:00
fhandle.c
file_table.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2014-06-12 10:30:18 -07:00
file.c fs/file.c: don't open-code kvfree() 2014-05-06 17:31:10 -04:00
filesystems.c
fs_pin.c make fs/{namespace,super}.c forget about acct.h 2014-08-07 14:40:09 -04:00
fs_struct.c
fs-writeback.c sched: Remove proliferation of wait_on_bit() action functions 2014-07-16 15:10:39 +02:00
inode.c mm: allow drivers to prevent new writable mappings 2014-08-08 15:57:31 -07:00
internal.h make fs/{namespace,super}.c forget about acct.h 2014-08-07 14:40:09 -04:00
ioctl.c
Kconfig
Kconfig.binfmt
libfs.c fs/libfs.c: add generic data flush to fsync 2014-06-04 16:53:55 -07:00
locks.c locks: pass correct "before" pointer to locks_unlink_lock in generic_add_lease 2014-08-22 09:58:22 -04:00
Makefile take fs_pin stuff to fs/* 2014-08-07 14:40:08 -04:00
mbcache.c fs/mbcache: replace __builtin_log2() with ilog2() 2014-06-25 22:08:29 -04:00
mount.h death to mnt_pinned 2014-08-07 14:40:09 -04:00
mpage.c fs/block_dev.c: add bdev_read_page() and bdev_write_page() 2014-06-04 16:54:02 -07:00
namei.c vfs: avoid non-forwarding large load after small store in path lookup 2014-09-14 17:28:32 -07:00
namespace.c fix EBUSY on umount() from MNT_SHRINKABLE 2014-08-30 18:32:05 -04:00
no-block.c
open.c vfs: fix check for fallocate on active swapfile 2014-08-01 02:36:04 -04:00
pipe.c new helper: copy_page_from_iter() 2014-05-06 17:39:42 -04:00
pnode.c get rid of propagate_umount() mistakenly treating slaves as busy. 2014-08-30 18:31:41 -04:00
pnode.h
posix_acl.c posix_acl: handle NULL ACL in posix_acl_equiv_mode 2014-05-06 13:58:42 -04:00
proc_namespace.c namespaces: Use task_lock and not rcu to protect nsproxy 2014-07-29 18:08:50 -07:00
read_write.c switch simple generic_file_aio_read() users to ->read_iter() 2014-05-06 17:37:55 -04:00
readdir.c fanotify: create FAN_ACCESS event for readdir 2014-06-04 16:53:52 -07:00
select.c
seq_file.c fs/seq_file: fallback to vmalloc allocation 2014-07-03 09:21:54 -07:00
signalfd.c
splice.c Merge commit '9f12600fe425bc28f0ccba034a77783c09c15af4' into for-linus 2014-06-12 00:28:09 -04:00
stack.c
stat.c
statfs.c
super.c Merge branch 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs 2014-08-13 17:45:40 -06:00
sync.c Export sync_filesystem() for modular ->remount_fs() use 2014-09-05 08:16:21 -07:00
timerfd.c timerfd: Use ktime_mono_to_real() 2014-07-23 10:18:02 -07:00
utimes.c
xattr.c simple_xattr: permit 0-size extended attributes 2014-07-23 15:10:55 -07:00