On Thu, Apr 28, 2011 at 02:59:27PM -0500, James Bottomley wrote: > On Thu, 2011-04-28 at 20:21 +0100, Mel Gorman wrote: > > On Thu, Apr 28, 2011 at 01:30:36PM -0500, James Bottomley wrote: > > > > Way hey, cgroups are also in the mix. How jolly. > > > > > > > > Is systemd a common element of the machines hitting this bug by any > > > > chance? > > > > > > Well, yes, the bug report is against FC15, which needs cgroups for > > > systemd. > > > > > > > Ok although we do not have direct evidence that it's the problem yet. A > > broken shrinker could just mean we are also trying to aggressively > > reclaim in cgroups. > > > > > > The remaining traces seem to be follow-on damage related to the three > > > > issues of "shrinkers are bust in some manner" causing "we are not > > > > getting over the min watermark" and as a side-show "we are spending lots > > > > of time doing something unspecified but unhelpful in cgroups". > > > > > > Heh, well find a way for me to verify this: I can't turn off cgroups > > > because systemd then won't work and the machine won't boot ... > > > > > > > Same testcase, same kernel but a distro that is not using systemd to > > verify if cgroups are the problem. Not ideal I know. When I'm back > > online Tuesday, I'll try reproducing this on a !Fedora distribution. In > > the meantime, the following untested hatchet job might spit out > > which shrinker we are getting stuck in. It is also breaking out of > > the shrink_slab loop so it'd even be interesting to see if the bug > > is mitigated in any way. > > 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. > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index c74a501..ed99104 100644 > > In the mean time, this patch produces: > > (that's nothing ... apparently the trace doesn't activate when kswapd > goes mad). > Or is looping there for shorter than we expect. HZ/10? -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
