On Sat, Nov 23, 2013 at 12:09:24AM +0000, Mel Gorman wrote: > On Fri, Nov 22, 2013 at 11:05:24PM +0000, Mel Gorman wrote: > > On Fri, Nov 22, 2013 at 03:28:07PM -0600, Alex Thorlton wrote: > > > > If the warning added by that patch does *not* trigger than can you also > > > > test this patch? It removes the barriers which should not be necessary > > > > and takes a reference tot he page before waiting on the lock. The > > > > previous version did not take the reference because otherwise the > > > > WARN_ON could not distinguish between a migration waiter and a surprise > > > > gup. > > > > > > Sorry for the delay; been a bit busy. I tested both of these patches on > > > top of this one (separately, of course): > > > > > > http://www.spinics.net/lists/linux-mm/msg63919.html > > > > > > I think that's the one you were referring to, if not send me a pointer > > > to the correct one and I'll give it another shot. Both patches still > > > segfaulted, so it doesn't appear that either of these solved the > > > problem. > > > > I see. Does THP have to be enabled or does it segfault even with THP > > disabled? It occurs with both THP on, and off. I get RCU stalls with THP on though. That's probably related to not having Kirill/Naoya's patches applied though. > > > > On a semi-related note, is the large machine doing anything with xpmem > or anything that depends on MMU notifiers to work properly? I noted > while looking at this that THP migration is not invalidating pages which > might be confusing a driver depending on it. I'm not using xpmem on any of the machines that I've been testing on, and I don't think that anything should be using MMU notifiers. - Alex -- 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>