Re: [libvirt] [PATCH 0/3] several cgroups/cpuset fixes

On Fri, 8 Jan 2016 11:05:59 -0500 John Ferlan <jferlan(a)redhat.com&gt; wrote: > >>> >>> I'm leaning towards something in the test. I'll check if reverting >>> these changes alters the results. I don't imagine it will. >> >> The real question is which thread it fails on and at what point in >> time. My patches only changed the order of operations where threads >> enter the cpuset cgroups at a slightly different time. And the qemu >> main thread never enters the parent group, it becomes an >> emulator-thread. Maybe you can point to exactly the assertion that >> fails. Including a link to the test code. And yes if you can >> confirm that the patches are to blame that would be a good first >> step ;). >> >> Thanks, >> Henning >> > > Update: > > I have found that if I revert patch 2... > > Then modify qemuInitCgroup() to modify the virCgroupNewMachine check > to also ensure "|| !priv->cgroup) I see the check for the parent cgroup should probably go back into virCgroupNewMachine, including the cleanup stuff in case of failure.

> Then modify qemuSetupCgroupForEmulator() to make the > virCgroupAddTask() call like was in patch 2 > > Then modify patch 3 (qemuSetupCgroupForVcpu) to change the call: > > > if (!cpumap) > continue; > > if (qemuSetupCgroupCpusetCpus(cgroup_vcpu, cpumap) < 0) > goto cleanup; > > to > > if (cpumap && > qemuSetupCgroupCpusetCpus(cgroup_vcpu, cpumap) < 0) > goto cleanup; > Well that is not a syntactical change, maybe easier to read and in line with the other places where qemuSetupCgroupCpusetCpus is called. > Then retest and the test passes again. > > Note that taking this route, I found that when I start the guest, I > have the following in 'tasks': > > # cat /sys/fs/cgroup/memory/machine.slice/tasks > # cat /sys/fs/cgroup/memory/machine.slice/*/tasks > 15007 > 15008 > 15010 > 15011 > 15013 > # > > Where '15007' is the virt-tests-vm1 process (eg, /proc/$pid/cgroup). > If I read the intentions you had, this follows that... > > I'll post a couple of patches in a bit... > > John