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| author |   Theodore Ts'o <tytso@mit.edu> | 2019-11-28 22:26:51 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2020-01-17 16:24:25 -0500 |
| commit | d4c5e960bf202d99ec9a6922ad387eafb798b848 (patch) | |
| tree | ee055127be4ebb1c9eccf1cee15185327255d6d2 /fs/ext4 | |
| parent | ext4: Optimize ext4 DIO overwrites (diff) | |
| download | linux-dev-d4c5e960bf202d99ec9a6922ad387eafb798b848.tar.xz linux-dev-d4c5e960bf202d99ec9a6922ad387eafb798b848.zip | |
ext4: avoid fetching btime in ext4_getattr() unless requested
Linus observed that an allmodconfig build which does a lot of stat(2)
calls that ext4_getattr() was a noticeable (1%) amount of CPU time,
due to the cache line for i_extra_isize getting pulled in. Since the
normal stat system call doesn't return btime, it's a complete waste.
So only calculate btime when it is explicitly requested.
[ Fixed to check against request_mask instead of query_flags. ]
Link: https://lore.kernel.org/r/CAHk-=wivmk_j6KbTX+Er64mLrG8abXZo0M10PNdAnHc8fWXfsQ@mail.gmail.com
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/inode.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index d035acab5b2a..9100460d92e5 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -5399,7 +5399,8 @@ int ext4_getattr(const struct path *path, struct kstat *stat, struct ext4_inode_info *ei = EXT4_I(inode); unsigned int flags; - if (EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) { + if ((request_mask & STATX_BTIME) && + EXT4_FITS_IN_INODE(raw_inode, ei, i_crtime)) { stat->result_mask |= STATX_BTIME; stat->btime.tv_sec = ei->i_crtime.tv_sec; stat->btime.tv_nsec = ei->i_crtime.tv_nsec; |