On Thu, 2011-05-12 at 14:13 +0300, Pekka Enberg wrote: > On 5/12/11 1:34 AM, James Bottomley wrote: > > On Wed, 2011-05-11 at 15:28 -0700, David Rientjes wrote: > >> On Wed, 11 May 2011, James Bottomley wrote: > >> > >>> OK, I confirm that I can't seem to break this one. No hangs visible, > >>> even when loading up the system with firefox, evolution, the usual > >>> massive untar, X and even a distribution upgrade. > >>> > >>> You can add my tested-by > >>> > >> Your system still hangs with patches 1 and 2 only? > > Yes, but only once in all the testing. With patches 1 and 2 the hang is > > much harder to reproduce, but it still seems to be present if I hit it > > hard enough. > > Patches 1-2 look reasonable to me. I'm not completely convinced of patch > 3, though. Why are we seeing these problems now? This has been in > mainline for a long time already. Shouldn't we fix kswapd? So I'm open to this. The hang occurs when kswapd races around in shrink_slab and never exits. It looks like there's a massive number of wakeups triggering this, but we haven't been able to diagnose it further. turning on PREEMPT gets rid of the hang, so I could try to reproduce with PREEMPT and turn on tracing. The problem so far has been that the number of events is so huge that the trace buffer only captures a few microseconds of output. 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>