On Tue, 18 Sep 2012, Glauber Costa wrote: > index f2d760c..18de3f6 100644 > --- a/mm/slab.c > +++ b/mm/slab.c > @@ -3938,9 +3938,12 @@ EXPORT_SYMBOL(__kmalloc); > * Free an object which was previously allocated from this > * cache. > */ > -void kmem_cache_free(struct kmem_cache *cachep, void *objp) > +void kmem_cache_free(struct kmem_cache *s, void *objp) > { > unsigned long flags; > + struct kmem_cache *cachep = virt_to_cache(objp); > + > + VM_BUG_ON(!slab_equal_or_parent(cachep, s)); > This is an extremely hot path of the kernel and you are adding significant processing. Check how the benchmarks are influenced by this change. virt_to_cache can be a bit expensive. > diff --git a/mm/slub.c b/mm/slub.c > index 4778548..a045dfc 100644 > --- a/mm/slub.c > +++ b/mm/slub.c > @@ -2604,7 +2604,9 @@ void kmem_cache_free(struct kmem_cache *s, void *x) > > page = virt_to_head_page(x); > > - slab_free(s, page, x, _RET_IP_); > + VM_BUG_ON(!slab_equal_or_parent(page->slab, s)); > + > + slab_free(page->slab, page, x, _RET_IP_); > Less of a problem here but you are eroding one advantage that slab has had in the past over slub in terms of freeing objects. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html