Re: [RFC PATCH 0/2] workqueue: Introduce PF_WQ_RESCUE_WORKER

From: Tejun Heo
Date: Tue Dec 12 2023 - 12:14:56 EST


Hello, Juri.

On Tue, Dec 12, 2023 at 10:56:02AM +0100, Juri Lelli wrote:
> Hummm, OK, but in terms of which CPU the rescuer is possibly woken up,
> how are we making sure that the wake up is always happening on
> housekeeping CPUs (assuming unbound workqueues have been restricted to
> those)?
>
> AFAICS, we have
>
> send_mayday ->
> wake_up_process(wq->rescuer->task)
>
> which is not affined to the workqueue cpumask it's called to rescue, so
> in theory can be woken up anywhere?

Ah, was only thinking about work item execution. Yeah, it's not following
the isolation rule there and we probably should affine it as we're waking it
up.

Thanks.

--
tejun