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authorSebastien Buisson <sebastien.buisson@bull.net>2014-10-09 15:29:38 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-10-09 22:26:02 -0400
commit86cf78d73de8c6bfa89804b91ee0ace71a459961 (patch)
tree2cb7facefd7c5609bde031400b8a4130da67ef21
parent2c0346a36cc8ac6cb85ab585964590974c84bdf0 (diff)
fs/buffer.c: increase the buffer-head per-CPU LRU size
Increase the buffer-head per-CPU LRU size to allow efficient filesystem operations that access many blocks for each transaction. For example, creating a file in a large ext4 directory with quota enabled will access multiple buffer heads and will overflow the LRU at the default 8-block LRU size: * parent directory inode table block (ctime, nlinks for subdirs) * new inode bitmap * inode table block * 2 quota blocks * directory leaf block (not reused, but pollutes one cache entry) * 2 levels htree blocks (only one is reused, other pollutes cache) * 2 levels indirect/index blocks (only one is reused) The buffer-head per-CPU LRU size is raised to 16, as it shows in metadata performance benchmarks up to 10% gain for create, 4% for lookup and 7% for destroy. Signed-off-by: Liang Zhen <liang.zhen@intel.com> Signed-off-by: Andreas Dilger <andreas.dilger@intel.com> Signed-off-by: Sebastien Buisson <sebastien.buisson@bull.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/buffer.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/buffer.c b/fs/buffer.c
index 7bd5c4685e98..44c14a87750e 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1253,7 +1253,7 @@ static struct buffer_head *__bread_slow(struct buffer_head *bh)
* a local interrupt disable for that.
*/
-#define BH_LRU_SIZE 8
+#define BH_LRU_SIZE 16
struct bh_lru {
struct buffer_head *bhs[BH_LRU_SIZE];