tree bd8a5c5b13838a59cb68ce23db8846160bbc361b
parent 429267442af1ddc2f8d9f5195fc5e919b5ced301
author Hou Pengyang <houpengyang@huawei.com> 1453812986 +0000
committer Jaegeuk Kim <jaegeuk@kernel.org> 1456186043 -0800

f2fs: improve shrink performance of extent nodes

On the worst case, we need to scan the whole radix tree and every rb-tree to
free the victimed extent_nodes when shrinking.

Pengyang initially introduced a victim_list to record the victimed extent_nodes,
and free these extent_nodes by just scanning a list.

Later, Chao Yu enhances the original patch to improve memory footprint by
removing victim list.

The policy of lru list shrinking becomes:
1) lock lru list's lock
2) trylock extent tree's lock
3) remove extent node from lru list
4) unlock lru list's lock
5) do shrink
6) repeat 1) to 5)

Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Signed-off-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>