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authorEric Dumazet <dada1@cosmosbay.com>2007-05-06 14:49:28 -0700
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-05-07 12:12:53 -0700
commit6310984694c8204ad16a2414cd58808fae68e02b (patch)
tree9579700c6b8b99e873462018cf536c00ab76dfb6 /mm/slab.c
parent364fbb29a0105863d76a1f7bbc01783a4af30a75 (diff)
downloadlwn-6310984694c8204ad16a2414cd58808fae68e02b.tar.gz
lwn-6310984694c8204ad16a2414cd58808fae68e02b.zip
SLAB: don't allocate empty shared caches
We can avoid allocating empty shared caches and avoid unecessary check of cache->limit. We save some memory. We avoid bringing into CPU cache unecessary cache lines. All accesses to l3->shared are already checking NULL pointers so this patch is safe. Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> Acked-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Christoph Lameter <clameter@engr.sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/slab.c')
-rw-r--r--mm/slab.c26
1 files changed, 15 insertions, 11 deletions
diff --git a/mm/slab.c b/mm/slab.c
index ae440b5ba60e..00f98b9f6df1 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1223,19 +1223,20 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb,
*/
list_for_each_entry(cachep, &cache_chain, next) {
struct array_cache *nc;
- struct array_cache *shared;
+ struct array_cache *shared = NULL;
struct array_cache **alien = NULL;
nc = alloc_arraycache(node, cachep->limit,
cachep->batchcount);
if (!nc)
goto bad;
- shared = alloc_arraycache(node,
+ if (cachep->shared) {
+ shared = alloc_arraycache(node,
cachep->shared * cachep->batchcount,
0xbaadf00d);
- if (!shared)
- goto bad;
-
+ if (!shared)
+ goto bad;
+ }
if (use_alien_caches) {
alien = alloc_alien_cache(node, cachep->limit);
if (!alien)
@@ -1317,8 +1318,8 @@ static int __cpuinit cpuup_callback(struct notifier_block *nfb,
shared = l3->shared;
if (shared) {
- free_block(cachep, l3->shared->entry,
- l3->shared->avail, node);
+ free_block(cachep, shared->entry,
+ shared->avail, node);
l3->shared = NULL;
}
@@ -3870,12 +3871,15 @@ static int alloc_kmemlist(struct kmem_cache *cachep)
goto fail;
}
- new_shared = alloc_arraycache(node,
+ new_shared = NULL;
+ if (cachep->shared) {
+ new_shared = alloc_arraycache(node,
cachep->shared*cachep->batchcount,
0xbaadf00d);
- if (!new_shared) {
- free_alien_cache(new_alien);
- goto fail;
+ if (!new_shared) {
+ free_alien_cache(new_alien);
+ goto fail;
+ }
}
l3 = cachep->nodelists[node];