Re: [PATCH] sched/schedutil: Fix deadlock between cpuset and cpu hotplug when using schedutil

From: Tejun Heo
Date: Wed Jul 27 2022 - 18:05:50 EST


Hello,

On Thu, Jul 28, 2022 at 12:01:35AM +0200, Peter Zijlstra wrote:
> On Tue, Jul 12, 2022 at 06:13:46AM -1000, Tejun Heo wrote:
>
> > But now we're failing user-initiated operations randomly. I have a hard time
> > seeing that as an acceptable solution.
>
> There (sadly) is precedent for that; grep for "cpu_hotplug_disable".

Yeah, there's another one in cpu cgroup controller attach path. We should
get better at not doing these. Low frequency arbitrary failures are really
difficult to handle reliably downstream.

Thanks.

--
tejun