On Thu, 2011-04-28 at 15:07 +0100, Mel Gorman wrote: > On Thu, Apr 28, 2011 at 03:52:28PM +0200, Jan Kara wrote: > > On Thu 28-04-11 12:36:30, Colin Ian King wrote: > > > One more data point to add, I've been looking at an identical issue when > > > copying large amounts of data. I bisected this - and the lockups occur > > > with commit > > > 3e7d344970673c5334cf7b5bb27c8c0942b06126 - before that I don't see the > > > issue. With this commit, my file copy test locks up after ~8-10 > > > iterations, before this commit I can copy > 100 times and don't see the > > > lockup. > > Adding Mel to CC, I guess he'll be interested. Mel, it seems this commit > > of yours causes kswapd on non-preempt kernels spin for a *long* time... > > > > I'm still thinking about the traces which do not point the finger > directly at compaction per-se but it's possible that the change means > kswapd is not reclaiming like it should be. > > To test this theory, does applying > [d527caf2: mm: compaction: prevent kswapd compacting memory to reduce > CPU usage] help? I can answer definitively no to this. The upstream kernel I reproduced this on has that patch included. James -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>