linux-kernel - Re: [PATCH 1/1] PM: WQ_PERCPU added to alloc

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Message-ID: <CAAofZF6uid+TAcz6P9WDXHWXrJMjNHdqgFuN8kf4w=ZSf7t5AQ@mail.gmail.com>
Date: Fri, 5 Sep 2025 18:21:09 +0200
From: Marco Crivellari <marco.crivellari@...e.com>
To: "Rafael J. Wysocki" <rafael@...nel.org>
Cc: linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org, 
	Tejun Heo <tj@...nel.org>, Lai Jiangshan <jiangshanlai@...il.com>, 
	Frederic Weisbecker <frederic@...nel.org>, Sebastian Andrzej Siewior <bigeasy@...utronix.de>, 
	Michal Hocko <mhocko@...e.com>, Pavel Machek <pavel@...nel.org>, Len Brown <len.brown@...el.com>
Subject: Re: [PATCH 1/1] PM: WQ_PERCPU added to alloc_workqueue users

On Fri, Sep 5, 2025 at 4:04 PM Rafael J. Wysocki <rafael@...nel.org> wrote:
> Duplicate paragraph.
>
> > This patch adds a new WQ_PERCPU flag to explicitly request the use of
>
> Using phrases like "this patch" in kernel patch changelogs is
> discouraged because the patches become commits when they go into git
> and then the language becomes slightly odd.  You can say "this change"
> instead.

Hello,

Thank you for the advice!

> > @@ -1012,7 +1012,7 @@ EXPORT_SYMBOL_GPL(pm_wq);
> >
> >  static int __init pm_start_workqueue(void)
> >  {
> > -       pm_wq = alloc_workqueue("pm", WQ_FREEZABLE, 0);
> > +       pm_wq = alloc_workqueue("pm", WQ_FREEZABLE | WQ_PERCPU, 0);
>
> I have no strong opinion on the change itself.
>
> While preserving the current behavior is prudent, this particular
> workqueue may as well be better off as WQ_UNBOUND.

Thanks for the info, about this specific wq.

All the users have been massively converted in this step.
So we added WQ_PERCPU if WQ_UNBOUND wasn't present, to make explicit
it is per-cpu - as you said, keeping the current behavior.

A next step will involve exactly what you said: remove the WQ_PERCPU flag
where not necessary.

Thanks!

-- 

Marco Crivellari

L3 Support Engineer, Technology & Product




marco.crivellari@...e.com