SLUB: Avoid checking for a valid object before zeroing on the fastpath The fastpath always results in a valid object. Move the check for the NULL pointer to the slow branch that calls __slab_alloc. Only __slab_alloc can return NULL if there is no memory available. Signed-off-by: Christoph Lameter --- mm/slub.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) Index: linux-2.6/mm/slub.c =================================================================== --- linux-2.6.orig/mm/slub.c 2007-10-19 13:06:49.000000000 -0700 +++ linux-2.6/mm/slub.c 2007-10-19 13:08:30.000000000 -0700 @@ -1567,17 +1567,20 @@ static void __always_inline *slab_alloc( local_irq_save(flags); c = get_cpu_slab(s, smp_processor_id()); - if (unlikely(!c->freelist || !node_match(c, node))) + if (unlikely(!c->freelist || !node_match(c, node))) { object = __slab_alloc(s, gfpflags, node, addr, c); - - else { + if (unlikely(!object)) { + local_irq_restore(flags); + return NULL; + } + } else { object = c->freelist; c->freelist = object[c->offset]; } local_irq_restore(flags); - if (unlikely((gfpflags & __GFP_ZERO) && object)) + if (unlikely((gfpflags & __GFP_ZERO))) memset(object, 0, c->objsize); return object;