On Tue, Aug 21, 2012 at 04:23:58PM -0300, Rafael Aquini wrote: > On Tue, Aug 21, 2012 at 10:13:30PM +0300, Michael S. Tsirkin wrote: > > > > > > I believe rcu_dereference_protected() is what I want/need here, since this code > > > is always called for pages which we hold locked (PG_locked bit). > > > > It would only help if we locked the page while updating the mapping, > > as far as I can see we don't. > > > > But we can do it. In fact, by doing it (locking the page) we can easily avoid > the nasty race balloon_isolate_page / leak_balloon, in a much simpler way, IMHO. Absolutely. Further, we should look hard at whether most RCU uses in this patchset can be replaced with page lock. -- MST -- 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>