From: Christoph Lameter The fast path 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 anymore and that case is exceedingly rare. Signed-off-by: Christoph Lameter Reviewed-by: Pekka Enberg Signed-off-by: Andrew Morton --- mm/slub.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff -puN mm/slub.c~slub-avoid-checking-for-a-valid-object-before-zeroing-on-the-fast-path mm/slub.c --- a/mm/slub.c~slub-avoid-checking-for-a-valid-object-before-zeroing-on-the-fast-path +++ a/mm/slub.c @@ -1573,19 +1573,22 @@ static __always_inline void *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); + goto out; + } + } 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); - +out: return object; } _