Btrfs: cache the extent map struct when reading several pages
authorMiao Xie <miaox@cn.fujitsu.com>
Thu, 25 Jul 2013 11:22:37 +0000 (19:22 +0800)
committerChris Mason <chris.mason@fusionio.com>
Sun, 1 Sep 2013 12:04:36 +0000 (08:04 -0400)
commit125bac016d60e78120e92904a5b2fc3a5ebf0475
treed3120749dacb8646f8d2af851c390f79a3c86640
parent9974090bdd7ac310d99a8ce6da7d6a19b3099ff9
Btrfs: cache the extent map struct when reading several pages

When we read several pages at once, we needn't get the extent map object
every time we deal with a page, and we can cache the extent map object.
So, we can reduce the search time of the extent map, and besides that, we
also can reduce the lock contention of the extent map tree.

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
fs/btrfs/extent_io.c