On Fri, Dec 06, 2013 at 09:24:00AM +0000, Mel Gorman wrote: > Good. So far I have not been seeing any problems with it at least. I went through and tested all the different iterations of this patchset last night, and have hit a few problems, but I *think* this has solved the segfault problem. I'm now hitting some rcu_sched stalls when running my tests. Initially things were getting hung up on a lock in change_huge_pmd, so I applied Kirill's patches to split up the PTL, which did manage to ease the contention on that lock, but, now it appears that I'm hitting stalls somewhere else. I'll play around with this a bit tonight/tomorrow and see if I can track down exactly where things are getting stuck. Unfortunately, on these large systems, when we hit a stall, the system often completely locks up before the NMI backtrace can complete on all cpus, so, as of right now, I've not been able to get a backtrace for the cpu that's initially causing the stall. I'm going to see if I can slim down the code for the stall detection to just give the backtrace for the cpu that's initially stalling out. In the meantime, let me know if you guys have any ideas that could keep things moving. - 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>