SLUB: Use ->objsize from struct kmem_cache_cpu in slab_free()

There's no reason to use ->objsize from struct kmem_cache in slab_free() for
the SLAB_DEBUG_OBJECTS case. All it does is generate extra cache pressure as we
try very hard not to touch struct kmem_cache in the fast-path.

Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>

mm/slub.c

@@ -1724,7 +1724,7 @@ static __always_inline void slab_free(struct kmem_cache *s,
 	c = get_cpu_slab(s, smp_processor_id());
 	debug_check_no_locks_freed(object, c->objsize);
 	if (!(s->flags & SLAB_DEBUG_OBJECTS))
-		debug_check_no_obj_freed(object, s->objsize);
+		debug_check_no_obj_freed(object, c->objsize);
 	if (likely(page == c->page && c->node >= 0)) {
 		object[c->offset] = c->freelist;
 		c->freelist = object;