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 <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

1 files changed, 1 insertions, 1 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 96c10934bb96..4a01ba315262 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1268,7 +1268,6 @@ struct ext4_sb_info {
         atomic_t s_mb_preallocated;
         atomic_t s_mb_discarded;
         atomic_t s_lock_busy;
-        atomic_t s_extent_cache_cnt;
 
         /* locality groups */
         struct ext4_locality_group __percpu *s_locality_groups;
@@ -1310,6 +1309,7 @@ struct ext4_sb_info {
         /* Reclaim extents from extent status tree */
         struct shrinker s_es_shrinker;
         struct list_head s_es_lru;
+        struct percpu_counter s_extent_cache_cnt;
         spinlock_t s_es_lru_lock ____cacheline_aligned_in_smp;
 };