On Tue, 2011-05-03 at 10:13 +0100, Mel Gorman wrote: > On Thu, Apr 28, 2011 at 05:43:48PM -0500, James Bottomley wrote: > > On Thu, 2011-04-28 at 16:12 -0500, James Bottomley wrote: > > > On Thu, 2011-04-28 at 14:59 -0500, James Bottomley wrote: > > > > Actually, talking to Chris, I think I can get the system up using > > > > init=/bin/bash without systemd, so I can try the no cgroup config. > > > > > > OK, so a non-PREEMPT non-CGROUP kernel has survived three back to back > > > runs of untar without locking or getting kswapd pegged, so I'm pretty > > > certain this is cgroups related. The next steps are to turn cgroups > > > back on but try disabling the memory and IO controllers. > > > > I tried non-PREEMPT CGROUP but disabled GROUP_MEM_RES_CTLR. > > > > The results are curious: the tar does complete (I've done three back to > > back). However, I did get one soft lockup in kswapd (below). But the > > system recovers instead of halting I/O and hanging like it did > > previously. > > > > The soft lockup is in shrink_slab, so perhaps it's a combination of slab > > shrinker and cgroup memory controller issues? > > > > So, kswapd is still looping in reclaim and spending a lot of time in > shrink_slab but it must not be the shrinker itself or that debug patch > would have triggered. It's curious that cgroups are involved with > systemd considering that one would expect those groups to be fairly > small. I still don't have a new theory but will get hold of a Fedora 15 > install CD and see can I reproduce it locally. I've got a ftrace output of kswapd ... it's 500k compressed, so I'll send under separate cover. > One last thing, what is the value of /proc/sys/vm/zone_reclaim_mode? Two > of the reporting machines could be NUMA and if that proc file reads as > 1, I'd be interested in hearing the results of a test with it set to 0. > Thanks. It's zero, I'm afraid 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>