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

Tejun Heo
2024-02-07T18:58:04Z

On Wed, Feb 07, 2024 at 07:55:51PM +0100, Marek Szyprowski wrote:
> On 07.02.2024 17:39, Tejun Heo wrote:
> > 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? If so, the max_active should already be way higher than the
> > WQ_DFL_MIN_ACTIVE. Also, are these multi node NUMA machines? Otherwise, it
> > really shouldn't affect anything. One easy way to verify would be just
> > bumping up WQ_DFL_MIN_ACTIVE and see what happens.
>
> I've increased WQ_DFL_MIN_ACTIVE from 8 to 32 and all the system
> suspend/resume issues went away. :)

Ah, okay, that's surprising. Lemme look at the code again. I gotta be
missing something.

Thanks.

--
tejun