Re: [PATCH v1] PM: sleep: Restore asynchronous device resume optimization

Rafael J. Wysocki
2024-02-07T18:41:44Z

On Wed, Feb 7, 2024 at 5:40 PM Tejun Heo <tj@kernel.org> wrote:
>
> Hello,
>
> On Wed, Feb 07, 2024 at 12:25:46PM +0100, Rafael J. Wysocki wrote:
> > The other one is that what happens during async resume does not meet
> > the assumptions of commit 5797b1c18919 (for example, it can easily
> > produce a chain of interdependent work items longer than 8) and so it
> > breaks things.
>
> Ah, that's fascinating. But aren't CPUs all brought up online before devices
> are resumed?

They are.

> If so, the max_active should already be way higher than the
> WQ_DFL_MIN_ACTIVE. Also, are these multi node NUMA machines?

They aren't.

> Otherwise, it really shouldn't affect anything.

Well, it evidently makes a difference. I'm wondering what difference
it can make in that case.

> One easy way to verify would be just bumping up WQ_DFL_MIN_ACTIVE and see what happens.

Sure.