Re: [PATCH 1/5] cgroup/cpuset: Skip task update if hotplug doesn't affect current cpuset

[Waiman Long]

On 3/14/23 12:50, Michal Koutný wrote:
> On Mon, Mar 06, 2023 at 03:08:45PM -0500, Waiman Long <longman@xxxxxxxxxx> wrote:
> > If a hotplug event doesn't affect the current cpuset, there is no point
> > to call hotplug_update_tasks() or hotplug_update_tasks_legacy(). So
> > just skip it.
> This skips "insane" modification of cs->cpus_allowed in
> hotplug_update_tasks_legacy() but assuming cs->cpus_allowed is kept in
> sync with cs->effective_cpus on v1, it is OK to skip the update based
> only on effective_cpus check.

Yes, effective_cpus is equivalent to cpus_allowed in v1 unless you mount 
the cpuset with the cpuset_v2_mode flag which will behave more like v2 
where effective_cpus is still the key.

Cheers,
Longman