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authorEric Dumazet <dada1@cosmosbay.com>2006-03-26 04:37:24 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-26 11:56:56 -0500
commitfa3536cc144c1298f2ed9416c33f3b77fa2cd37a (patch)
tree5484541319b86ae7dac0def4db7925f7cc7008e7 /fs/bio.c
parent878a9f30d7b13015f3aa4534d7877d985f150183 (diff)
[PATCH] Use __read_mostly on some hot fs variables
I discovered on oprofile hunting on a SMP platform that dentry lookups were slowed down because d_hash_mask, d_hash_shift and dentry_hashtable were in a cache line that contained inodes_stat. So each time inodes_stats is changed by a cpu, other cpus have to refill their cache line. This patch moves some variables to the __read_mostly section, in order to avoid false sharing. RCU dentry lookups can go full speed. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/bio.c')
-rw-r--r--fs/bio.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/bio.c b/fs/bio.c
index 73e664c01d30..49db9286a3b4 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -30,7 +30,7 @@
30 30
31#define BIO_POOL_SIZE 256 31#define BIO_POOL_SIZE 256
32 32
33static kmem_cache_t *bio_slab; 33static kmem_cache_t *bio_slab __read_mostly;
34 34
35#define BIOVEC_NR_POOLS 6 35#define BIOVEC_NR_POOLS 6
36 36
@@ -39,7 +39,7 @@ static kmem_cache_t *bio_slab;
39 * basically we just need to survive 39 * basically we just need to survive
40 */ 40 */
41#define BIO_SPLIT_ENTRIES 8 41#define BIO_SPLIT_ENTRIES 8
42mempool_t *bio_split_pool; 42mempool_t *bio_split_pool __read_mostly;
43 43
44struct biovec_slab { 44struct biovec_slab {
45 int nr_vecs; 45 int nr_vecs;