linux-kernel - Re: [PATCH] platform/surface: acpi-notify: add WQ_PERCPU to alloc

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Message-ID: <CAAofZF7GwRKQcNAUK9=j4mqnz+HX_ONG9YKs4PLztbjvJxrxZg@mail.gmail.com>
Date: Wed, 19 Nov 2025 11:56:25 +0100
From: Marco Crivellari <marco.crivellari@...e.com>
To: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Cc: LKML <linux-kernel@...r.kernel.org>, platform-driver-x86@...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>, Maximilian Luz <luzmaximilian@...il.com>, 
	Hans de Goede <hansg@...nel.org>
Subject: Re: [PATCH] platform/surface: acpi-notify: add WQ_PERCPU to
 alloc_workqueue users

On Wed, Nov 19, 2025 at 11:38 AM Ilpo Järvinen
<ilpo.jarvinen@...ux.intel.com> wrote:
> [...]
> So after refactoring, WQ_UNBOUND cannot be specified as it has been
> removed AND the default behavior is "unbound", not "per-cpu", right?
> So it should be other way around, e.g.:
>
> The refactoring is going to alter the behavior of alloc_workqueue() to be
> unbound by default.

Yes, it makes sense. I changed that part.

This is the updated version:

This continues the effort to refactor workqueue APIs, which began with
the introduction of new workqueues and a new alloc_workqueue flag in:

commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

The refactoring is going to alter the default behavior of
alloc_workqueue() to be unbound by default.

With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND),
any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND
must now use WQ_PERCPU. For more details see the Link tag below.

In order to keep alloc_workqueue() behavior identical, explicitly request
WQ_PERCPU.

Thanks!

-- 

Marco Crivellari

L3 Support Engineer, Technology & Product