On 11/13/2015 11:57 AM, Henning Schild wrote:
> The machine cgroup is a superset, a parent to the emulator and vcpuX
> cgroups. The parent cgroup should never have any tasks directly in it.
> In fact the parent cpuset might contain way more cpus than the sum of
> emulatorpin and vcpupins. So putting tasks in the superset will allow
> them to run outside of <cputune>.
>
> Signed-off-by: Henning Schild <henning.schild@xxxxxxxxxxx>
> ---
> src/qemu/qemu_cgroup.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/src/qemu/qemu_cgroup.c b/src/qemu/qemu_cgroup.c
> index 28d2ca2..2c74a22 100644
> --- a/src/qemu/qemu_cgroup.c
> +++ b/src/qemu/qemu_cgroup.c
> @@ -769,12 +769,6 @@ qemuInitCgroup(virQEMUDriverPtr driver,
> goto cleanup;
> }
>
> - if (virCgroupAddTask(priv->cgroup, vm->pid) < 0) {
> - virCgroupRemove(priv->cgroup);
> - virCgroupFree(&priv->cgroup);
> - goto cleanup;
> - }
> -
Moving this to later would also seem to imply that the code after the
qemuSetupCgroup (which calls qemuInitCgroup) from qemuProcessLaunch
would need some movement too, e.g.:
/* This must be done after cgroup placement to avoid resetting CPU
* affinity */
if (!vm->def->cputune.emulatorpin &&
qemuProcessInitCpuAffinity(vm) < 0)
goto cleanup;
Theoretically that would then need to be between the following:
VIR_DEBUG("Setting cgroup for emulator (if required)");
if (qemuSetupCgroupForEmulator(vm) < 0)
goto cleanup;
<<<... right here, I believe ...>>>
VIR_DEBUG("Setting affinity of emulator threads");
if (qemuProcessSetEmulatorAffinity(vm) < 0)
goto cleanup;
Again, weak ACK - hopefully Peter/Martin can take a look. In any case a
v2 probably should be done.
John
> done:
> ret = 0;
> cleanup:
> @@ -1145,6 +1139,10 @@ qemuSetupCgroupForEmulator(virDomainObjPtr vm)
> goto cleanup;
> }
>
> + /* consider the first thread an emulator-thread */
> + if (virCgroupAddTask(cgroup_emulator, vm->pid) < 0)
> + goto cleanup;
> +
> virCgroupFree(&cgroup_emulator);
> return 0;
>
>
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