On 01/14/2016 06:24 AM, Joonsoo Kim wrote: > In fact, I tested another idea implementing OBJFREELIST_SLAB with > extendable linked array through another freed object. It can remove > memory waste completely but it causes more computational overhead > in critical lock path and it seems that overhead outweigh benefit. > So, this patch doesn't include it. Can you elaborate? Do we actually need an extendable linked array? Why not just store the pointer to the next free object into the object, NULL for the last one? I.e. a singly-linked list. We should never need to actually traverse it? freeing object obj: *obj = page->freelist; page->freelist = obj; allocating object: obj = page->freelist; page->freelist = *obj; *obj = NULL; That means two writes, but if we omit managing page->active, it's not an increase. For counting free objects, we would need to traverse the list, but that's only needed for debugging? Also during bulk operations, page->freelist could be updated just once at the very end. Vlastimil -- 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>