From 1ac6466f253ef7bd063b7877fb056afe1820841c Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 2 Mar 2013 10:27:46 -0500 Subject: ext4: use percpu counter for extent cache count Use a percpu counter rather than atomic types for shrinker accounting. There's no need for ultimate accuracy in the shrinker, so this should come a little more cheaply. The percpu struct is somewhat large, but there was a big gap before the cache-aligned s_es_lru_lock anyway, and it fits nicely in there. Signed-off-by: Eric Sandeen Signed-off-by: "Theodore Ts'o" --- fs/ext4/extents_status.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'fs/ext4/extents_status.c') diff --git a/fs/ext4/extents_status.c b/fs/ext4/extents_status.c index 27fcdd2b2607..95796a1b7522 100644 --- a/fs/ext4/extents_status.c +++ b/fs/ext4/extents_status.c @@ -305,7 +305,7 @@ ext4_es_alloc_extent(struct inode *inode, ext4_lblk_t lblk, ext4_lblk_t len, */ if (!ext4_es_is_delayed(es)) { EXT4_I(inode)->i_es_lru_nr++; - atomic_inc(&EXT4_SB(inode->i_sb)->s_extent_cache_cnt); + percpu_counter_inc(&EXT4_SB(inode->i_sb)->s_extent_cache_cnt); } return es; @@ -317,7 +317,7 @@ static void ext4_es_free_extent(struct inode *inode, struct extent_status *es) if (!ext4_es_is_delayed(es)) { BUG_ON(EXT4_I(inode)->i_es_lru_nr == 0); EXT4_I(inode)->i_es_lru_nr--; - atomic_dec(&EXT4_SB(inode->i_sb)->s_extent_cache_cnt); + percpu_counter_dec(&EXT4_SB(inode->i_sb)->s_extent_cache_cnt); } kmem_cache_free(ext4_es_cachep, es); @@ -678,7 +678,7 @@ static int ext4_es_shrink(struct shrinker *shrink, struct shrink_control *sc) int nr_to_scan = sc->nr_to_scan; int ret, nr_shrunk = 0; - ret = atomic_read(&sbi->s_extent_cache_cnt); + ret = percpu_counter_read_positive(&sbi->s_extent_cache_cnt); trace_ext4_es_shrink_enter(sbi->s_sb, nr_to_scan, ret); if (!nr_to_scan) @@ -711,7 +711,7 @@ static int ext4_es_shrink(struct shrinker *shrink, struct shrink_control *sc) list_splice_tail(&scanned, &sbi->s_es_lru); spin_unlock(&sbi->s_es_lru_lock); - ret = atomic_read(&sbi->s_extent_cache_cnt); + ret = percpu_counter_read_positive(&sbi->s_extent_cache_cnt); trace_ext4_es_shrink_exit(sbi->s_sb, nr_shrunk, ret); return ret; } -- cgit v1.2.1