tree 2fd4f5447094d374a1645ee8d4dfaf8649c97f95
parent 63541927c8d11d2686778b1e8ec71c14b4fd53e4
author Josef Bacik <jbacik@fb.com> 1389810853 -0500
committer Chris Mason <clm@fb.com> 1390944025 -0800

Btrfs: make fsync latency less sucky

Looking into some performance related issues with large amounts of metadata
revealed that we can have some pretty huge swings in fsync() performance.  If we
have a lot of delayed refs backed up (as you will tend to do with lots of
metadata) fsync() will wander off and try to run some of those delayed refs
which can result in reading from disk and such.  Since the actual act of fsync()
doesn't create any delayed refs there is no need to make it throttle on delayed
ref stuff, that will be handled by other people.  With this patch we get much
smoother fsync performance with large amounts of metadata.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>