linux-kernel - Re: [PATCH v2 0/2] rust: replace use of system_unbound_wq and system

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Message-ID: <CANiq72kJxwEncXVVrZoMyjXrtsJUGf+kamz0G+d2we7Fk1Vp6w@mail.gmail.com>
Date: Mon, 8 Sep 2025 18:32:09 +0200
From: Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
To: Marco Crivellari <marco.crivellari@...e.com>
Cc: linux-kernel@...r.kernel.org, rust-for-linux@...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>, Miguel Ojeda <ojeda@...nel.org>, Alex Gaynor <alex.gaynor@...il.com>, 
	Alice Ryhl <aliceryhl@...gle.com>
Subject: Re: [PATCH v2 0/2] rust: replace use of system_unbound_wq and system_wq

On Mon, Sep 8, 2025 at 6:02 PM Marco Crivellari
<marco.crivellari@...e.com> wrote:
>
> Below is a summary of a discussion about the Workqueue API and cpu isolation
> considerations. Details and more information are available here:

If I understand correctly, these two patches are "just" following the
C side, right?

i.e. the summary below comes from that original patch series, but this
one is just adding the `system_{dfl,percpu}_wq`s that were added on
the C side.

In other words, I would have just said that, plus a link to the patch
series or commit that actually added the new wqs.

I would do so similarly in the commit messages.

> === Introduced Changes by this series ===
>
> 1) [P 1-2] Replace use of system_wq and system_unbound_wq
>
>         system_wq is a per-CPU workqueue, but his name is not clear.
>         system_unbound_wq is to be used when locality is not required.
>
>         Because of that, system_wq has been renamed in system_percpu_wq, and
>         system_unbound_wq has been renamed in system_dfl_wq.

This is not what the patches are doing? There is no replacement nor rename.

> === For Maintainers ===
>
> There are prerequisites for this series, already merged in the master branch.
> The commits are:
>
> 128ea9f6ccfb6960293ae4212f4f97165e42222d ("workqueue: Add system_percpu_wq and
> system_dfl_wq")
>
> 930c2ea566aff59e962c50b2421d5fcc3b98b8be ("workqueue: Add new WQ_PERCPU flag")

Why are these prerequisites if they are already merged?

Thanks!

Cheers,
Miguel