Btrfs: set plug for fsync
authorLiu Bo <bo.li.liu@oracle.com>
Wed, 15 Nov 2017 23:10:28 +0000 (16:10 -0700)
committerDavid Sterba <dsterba@suse.com>
Mon, 22 Jan 2018 15:08:13 +0000 (16:08 +0100)
commitbe96c7b8bb5477736fc1431bf7b0ae23a340bf4e
treeb900c92ed8a718f05f81779132754a0609ebce55
parent3f41bf90fcce6134f627c27b5f94bb38617f3b2e
Btrfs: set plug for fsync

Setting plug can merge adjacent IOs before dispatching IOs to the disk
driver.

Without plug, it'd not be a problem for single disk usecases, but for
multiple disks using raid profile, a large IO can be split to several
IOs of stripe length, and plug can be helpful to bring them together
for each disk so that we can save several disk access.

Moreover, fsync issues synchronous writes, so plug can really take
effect.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
fs/btrfs/file.c