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authorChao Yu <chao2.yu@samsung.com>2015-02-05 12:57:31 +0300
committerJaegeuk Kim <jaegeuk@kernel.org>2015-03-03 20:58:47 +0300
commit1dcc336b02bff3d38f173feac55a2b6c25a5fb54 (patch)
tree65224e862473f315da2817ca8f1c08202a8d5fdb /fs/f2fs/segment.c
parent8967215954a50947fbd9c2996232548bf6dd9062 (diff)
downloadlinux-1dcc336b02bff3d38f173feac55a2b6c25a5fb54.tar.xz
f2fs: enable rb-tree extent cache
This patch enables rb-tree based extent cache in f2fs. When we mount with "-o extent_cache", f2fs will try to add recently accessed page-block mappings into rb-tree based extent cache as much as possible, instead of original one extent info cache. By this way, f2fs can support more effective cache between dnode page cache and disk. It will supply high hit ratio in the cache with fewer memory when dnode page cache are reclaimed in environment of low memory. Storage: Sandisk sd card 64g 1.append write file (offset: 0, size: 128M); 2.override write file (offset: 2M, size: 1M); 3.override write file (offset: 4M, size: 1M); ... 4.override write file (offset: 48M, size: 1M); ... 5.override write file (offset: 112M, size: 1M); 6.sync 7.echo 3 > /proc/sys/vm/drop_caches 8.read file (size:128M, unit: 4k, count: 32768) (time dd if=/mnt/f2fs/128m bs=4k count=32768) Extent Hit Ratio: before patched Hit Ratio 121 / 1071 1071 / 1071 Performance: before patched real 0m37.051s 0m35.556s user 0m0.040s 0m0.026s sys 0m2.990s 0m2.251s Memory Cost: before patched Tree Count: 0 1 (size: 24 bytes) Node Count: 0 45 (size: 1440 bytes) v3: o retest and given more details of test result. Signed-off-by: Chao Yu <chao2.yu@samsung.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Diffstat (limited to 'fs/f2fs/segment.c')
-rw-r--r--fs/f2fs/segment.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index daee4ab913da..29c04edcb843 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -277,6 +277,9 @@ void f2fs_balance_fs(struct f2fs_sb_info *sbi)
void f2fs_balance_fs_bg(struct f2fs_sb_info *sbi)
{
+ /* try to shrink extent cache when there is no enough memory */
+ f2fs_shrink_extent_tree(sbi, EXTENT_CACHE_SHRINK_NUMBER);
+
/* check the # of cached NAT entries and prefree segments */
if (try_to_free_nats(sbi, NAT_ENTRY_PER_BLOCK) ||
excess_prefree_segs(sbi) ||