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

Rafael J. Wysocki
2024-02-12T14:57:33Z

Hi,

On Fri, Feb 9, 2024 at 1:20 AM Tejun Heo <tj@kernel.org> wrote:
>
> Hello,
>
> On Thu, Feb 08, 2024 at 08:47:12AM +0100, Marek Szyprowski wrote:
> > I've tried to get drgn running on the test target, but then I've noticed
> > that it is not possible to run it on ARM 32bit target, as it requires
> > PROC_KCORE support, which is 'Visible if: PROC_FS [=y] && MMU [=y] &&
> > !ARM [=y]' for some reasons.
>
> Bummer. I instrumented code on my test setup (x86) and couldn't repro usage
> of the dfl_pwq, unfortuantely.

On x86 there are fewer device links representing dependencies between
devices, because it doesn't use fw_devlink which is used on ARM
platforms (and other DT-based), so on x86 it is less likely to
reproduce this.

> Independent of understanding what's going on with the system_unbound_wq, the
> correct solution seems like using a dedicated workqueue with raised
> min_active. Just posted the patchset to do that:
>
> http://lkml.kernel.org/r/ZcVtzJvJCRV5OLM-@slm.duckdns.org

LGTM, thanks!