On Mon, 8 Sep 2014, Christoph Lameter wrote: > On Mon, 8 Sep 2014, Mikulas Patocka wrote: > > > I don't know what you mean. If someone allocates 10000 objects with sizes > > from 1 to 10000, you can't have 10000 slab caches - you can't have a slab > > cache for each used size. Also - you can't create a slab cache in > > interrupt context. > > Oh you can create them up front on bootup. And I think only the small > sizes matter. Allocations >=8K are pushed to the page allocator anyways. Only for SLUB. For SLAB, large allocations are still use SLAB caches up to 4M. But anyway - having 8K preallocated slab caches is too much. If you want to integrate this patch into the slab/slub subsystem, a better solution would be to store the exact size requested with kmalloc along the slab/slub object itself (before the preceding redzone). But it would result in duplicating the work - you'd have to repeat the logic in this patch three times - once for slab, once for slub and once for kmalloc_large/kmalloc_large_node. I don't know if it would be better than this patch. > > > We already have a redzone structure to check for writes over the end of > > > the object. Lets use that. > > > > So, change all three slab subsystems to use that. > > SLOB has no debugging features and I think that was intentional. We are > trying to unify the debug checks etc. Some work on that would be > appreciated. I think the kmalloc creation is already in slab_common.c Mikulas -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>