Re: [PATCH v2 2/6] perf/core: Introduce percpu perf_cgroup

From: Peter Zijlstra
Date: Tue Mar 22 2022 - 09:01:50 EST


On Tue, Mar 22, 2022 at 08:08:30PM +0800, Chengming Zhou wrote:
> Although we don't have incosistency problem any more, we can
> have other problem like:
>
> CPU1 CPU2
> (in context_switch) (attach running task)
> prev->cgroups = cgrp2
> perf_cgroup_sched_switch(prev, next)
> cgrp2 == cgrp2 is True
>

Again, I'm not following, how can you attach to a running task from
another CPU ?