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 <[EMAIL PROTECTED]>
diff --git a/mm/slab.c b/mm/slab.c
index a69d0a5..abf46ae 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -1223,19 +1223,20 @@ static int __cpuinit cpuup_callback(stru
*/
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 @@ #endif
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;
}
@@ -3812,12 +3813,15 @@ static int alloc_kmemlist(struct kmem_ca
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];
