The patch titled
vfs: optimize touch_time() too
has been added to the -mm tree. Its filename is
vfs-optimize-touch_time-too.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: vfs: optimize touch_time() too
From: Andi Kleen <andi@xxxxxxxxxxxxxx>
Do a similar optimization as earlier for touch_atime. Getting the lock in
mnt_get_write is relatively costly, so try all avenues to avoid it first.
This patch is careful to still only update inode fields inside the lock
region.
This didn't show up in benchmarks, but it's easy enough to do.
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: Valerie Aurora <vaurora@xxxxxxxxxx>
Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Dave Hansen <haveblue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/inode.c | 43 +++++++++++++++++++++++--------------------
1 file changed, 23 insertions(+), 20 deletions(-)
diff -puN fs/inode.c~vfs-optimize-touch_time-too fs/inode.c
--- a/fs/inode.c~vfs-optimize-touch_time-too
+++ a/fs/inode.c
@@ -1448,34 +1448,37 @@ void file_update_time(struct file *file)
{
struct inode *inode = file->f_path.dentry->d_inode;
struct timespec now;
- int sync_it = 0;
- int err;
+ enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;
+ /* First try to exhause all avenues to not sync */
if (IS_NOCMTIME(inode))
return;
- err = mnt_want_write_file(file);
- if (err)
- return;
-
now = current_fs_time(inode->i_sb);
- if (!timespec_equal(&inode->i_mtime, &now)) {
- inode->i_mtime = now;
- sync_it = 1;
- }
+ if (!timespec_equal(&inode->i_mtime, &now))
+ sync_it = S_MTIME;
- if (!timespec_equal(&inode->i_ctime, &now)) {
- inode->i_ctime = now;
- sync_it = 1;
- }
+ if (!timespec_equal(&inode->i_ctime, &now))
+ sync_it |= S_CTIME;
- if (IS_I_VERSION(inode)) {
- inode_inc_iversion(inode);
- sync_it = 1;
- }
+ if (IS_I_VERSION(inode))
+ sync_it |= S_VERSION;
+
+ if (!sync_it)
+ return;
+
+ /* Finally allowed to write? Takes lock. */
+ if (!mnt_want_write_file(file))
+ return;
- if (sync_it)
- mark_inode_dirty_sync(inode);
+ /* Only change inode inside the lock region */
+ if (sync_it & S_VERSION)
+ inode_inc_iversion(inode);
+ if (sync_it & S_CTIME)
+ inode->i_ctime = now;
+ if (sync_it & S_MTIME)
+ inode->i_mtime = now;
+ mark_inode_dirty_sync(inode);
mnt_drop_write(file->f_path.mnt);
}
EXPORT_SYMBOL(file_update_time);
_
Patches currently in -mm which might be from andi@xxxxxxxxxxxxxx are
linux-next.patch
x86-fix-x86-fix-pageattr-handling-for-lpage-percpu-allocator-and-re-enable-it.patch
vfs-optimization-for-touch_atime.patch
vfs-optimize-touch_time-too.patch
vfs-optimize-touch_time-too-fix.patch
hugetlb-restore-interleaving-of-bootmem-huge-pages.patch
documentation-memorytxt-remove-some-very-outdated-recommendations.patch
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