Re: [RFC PATCH 3/4] kernel/workqueue: Distinguish between general unbound and WQ_SYSFS cpumask changes

From: Tejun Heo
Date: Wed Jan 17 2024 - 12:12:26 EST


Hello,

On Wed, Jan 17, 2024 at 02:06:08PM +0100, Juri Lelli wrote:
> > This looks rather hacky. Can you elaborate how the current code misbehaves
> > with an example?
>
> I was trying to address the fact that ordered unbound workqueues didn't
> seem to reflect unbound_cpumask changes, e.g.
>
> wq_unbound_cpumask=00000003
>
> edac-poller ordered,E 0xffffffff 000000ff kworker/R-edac- 351 0xffffffff 000000ff
>
> vs.
>
> edac-poller ordered,E 00000003 kworker/R-edac- 349 00000003
>
> with the patch applied. But honestly, I'm now also not convinced what
> I'm proposing is correct, so I'll need to think more about it.
>
> Can you please confirm though that ordered unbound workqueues are not
> "special" for some reason and we would like them to follow
> unbound_cpumask changes as normal ubound workqueues?

They aren't special and should follow the normal unbound workqueue cpumask.

Thanks.

--
tejun