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>
This commit is contained in:
Eric Dumazet 2007-05-06 14:49:28 -07:00 committed by Linus Torvalds
parent 364fbb29a0
commit 6310984694
1 changed files with 15 additions and 11 deletions

View File

@ -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];