From 6310984694c8204ad16a2414cd58808fae68e02b Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 6 May 2007 14:49:28 -0700 Subject: [PATCH] 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 Acked-by: Pekka Enberg Cc: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab.c | 26 +++++++++++++++----------- 1 file changed, 15 insertions(+), 11 deletions(-) diff --git a/mm/slab.c b/mm/slab.c index ae440b5ba6..00f98b9f6d 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]; -- 2.39.5