> I've got an alternate approach for fixing this wart in lookup_ioctx()... > Instead of using an rbtree, just use the reserved id in the ring buffer > header to index an array pointing the ioctx. It's not finished yet, and > it needs to be tidied up, but is most of the way there. Yeah, that might work. Note that the patch wasn't using an rbtree, it was storing the pointer value in a *radix* which is why single lookups took so long. Presumably radix was used for RCU lookups. Your ring->id trick lets us use RCU with small ints instead of the context pointer. It might be worth using idr instead of rolling manual array code. It'd still be much faster than the list, but get rid of the large alloc, array walking, memcpy(), etc. - z -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html