Hello Peter, Lai
Sorry to disturb again, I'm still confused, when the CPU is offline, we active
call set_cpus_allowed_ptr function to reset per-cpu kthread cpumask,
in sched_cpu_dying function , migrate_tasks function will reset per-cpu
kthread's cpumask on runq, even if not on runq, when wake up, other online
CPUs will also be selected to run.
what I want to ask is why we take the initiative to set it up?
Thanks
Qiang
________________________________________
发件人: Peter Zijlstra <pet...@infradead.org>
发送时间: 2021年1月14日 17:11
收件人: Zhang, Qiang
抄送: linux-kernel@vger.kernel.org
主题: Re: Question on workqueue: Manually break affinity on hotplug
[Please note this e-mail is from an EXTERNAL e-mail address]
On Thu, Jan 14, 2021 at 08:03:23AM +0000, Zhang, Qiang wrote:
> Hello Peter
>
> Excuse me, I have some questions for you, about a description of this change:
>
> ''Don't rely on the scheduler to force break affinity for us -- it will
> stop doing that for per-cpu-kthreads."
>
> this mean when cpuhotplug, scheduler do not change affinity for
> per-cpu-kthread's task, if we not active setting affinity?
> but if per-cpu-kthread's task is not run state, when wake up, will reset
> it's affinity, this is done automatically.
>
> or is it, this place modified to fit the new one hotplug mechanism which
> ("sched/hotplug: Consolidate task migration on CPU unplug")?
https://lkml.kernel.org/r/20201214155457.3430-1-jiangshan...@gmail.com
https://lkml.kernel.org/r/20201218170919.2950-1-jiangshan...@gmail.com
https://lkml.kernel.org/r/20201226025117.2770-1-jiangshan...@gmail.com
https://lkml.kernel.org/r/20210111152638.2417-1-jiangshan...@gmail.com
https://lkml.kernel.org/r/20210112144344.850850...@infradead.org
