On Tue, 7 Jul 2009, Christoph Lameter wrote: > > + * Debugging flags that require metadata to be stored in the slab, up to > > + * DEBUG_SIZE in size. > > + */ > > +#define DEBUG_SIZE_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) > > +#define DEBUG_SIZE (3 * sizeof(void *) + 2 * sizeof(struct track)) > > There is no need for DEBUG_SIZE since slub keeps both the size of the > object kmem_cache->objsize and the size with the metadata kmem_cache->size > > If the order of both is different then the order would increase. > Without DEBUG_SIZE_FLAGS, the only way to determine what flags have increased the size is in calculate_sizes() and then disable them by default if slub_debug=O is specified. calculate_sizes() is used by the `store', `poison', and `red_zone' callbacks, so the admin still has the ability to enable these options even though slub_debug=O was used. So we can either mask off the size-increasing debug bits when the cache is created in kmem_cache_flags() like I did, or we can move the logic to calculate_sizes() with an added formal to determine whether this is from kmem_cache_open() or one of the attribute callbacks. I think my solution is the cleanest and provides a single entity, DEBUG_SIZE_FLAGS, which specifies the flags that slub_debug=O clears if the minimum order increases. -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
