On Fri, 6 Jul 2012, JoonSoo Kim wrote: > For example, > When we try to free object A at cpu 1, another process try to free > object B at cpu 2 at the same time. > object A, B is in same slab, and this slab is in full list. > > CPU 1 CPU 2 > prior = page->freelist; prior = page->freelist > .... ... > new.inuse--; new.inuse--; > taking lock try to take the lock, but failed, so > spinning... > free success spinning... > add_partial > release lock taking lock > fail cmpxchg_double_slab > retry > currently, we don't need lock > > At CPU2, we don't need lock anymore, because this slab already in partial list. For that scenario we could also simply do a trylock there and redo the loop if we fail. But still what guarantees that another process will not modify the page struct between fetching the data and a successful trylock? -- 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>