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

On 01/11/2016 06:38 AM, Henning Schild wrote: > 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. > Forgot to CC you (and Jan) on the 4 patch series I sent: http://www.redhat.com/archives/libvir-list/2016-January/msg00236.html Patches 2, 3, & 4 are related to above while patch 1 is for below.

John >> 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 >