From: Michal Hocko <mhocko@suse.com>
To: Marco Crivellari <marco.crivellari@suse.com>
Cc: linux-kernel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Frederic Weisbecker <frederic@kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [PATCH 4/4] Workqueue: add WQ_PERCPU to every alloc_workqueue user
Date: Mon, 5 May 2025 11:22:16 +0200 [thread overview]
Message-ID: <aBiDSHee4TKs8HF-@tiehlicka> (raw)
In-Reply-To: <20250503082834.49413-5-marco.crivellari@suse.com>
On Sat 03-05-25 10:28:34, Marco Crivellari wrote:
> By default, alloc_workqueue() creates bound workqueues
> (i.e., without WQ_UNBOUND).
>
> 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.
>
> All existing users have been updated accordingly.
I assume that the next step is to drop WQ_PERCPU when it is not strictly
necessary, right?
Looking at the huge list this will be a huge undergoing. Is there any
rule of thumb to tell whether WQ_PERCPU is required or not? Maybe
something as simple as - if the worker doesn't use any per cpu variables
then it is highly likely that it doesn't need WQ_PERCPU? Are there other
useful hints?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2025-05-05 9:22 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-03 8:28 [PATCH 0/4] Workqueue: rename system workqueue and add WQ_PERCPU Marco Crivellari
2025-05-03 8:28 ` [PATCH 1/4] Workqueue: rename system_wq to system_percpu_wq Marco Crivellari
2025-05-03 8:28 ` [PATCH 2/4] Workqueue: rename system_unbound_wq to system_dfl_wq Marco Crivellari
2025-05-03 8:28 ` [PATCH 3/4] Workqueue: add WQ_PERCPU Marco Crivellari
2025-05-03 8:28 ` [PATCH 4/4] Workqueue: add WQ_PERCPU to every alloc_workqueue user Marco Crivellari
2025-05-05 6:56 ` Sebastian Andrzej Siewior
2025-05-05 9:22 ` Michal Hocko [this message]
2025-05-06 12:36 ` Frederic Weisbecker
2025-05-05 6:51 ` [PATCH 0/4] Workqueue: rename system workqueue and add WQ_PERCPU Sebastian Andrzej Siewior
2025-05-05 7:55 ` Marco Crivellari
2025-05-05 9:25 ` Michal Hocko
2025-05-06 7:53 ` Marco Crivellari
2025-05-05 23:39 ` Tejun Heo
2025-05-06 10:10 ` Marco Crivellari
2025-05-06 12:55 ` Frederic Weisbecker
2025-05-07 0:42 ` Tejun Heo
2025-05-07 12:04 ` Frederic Weisbecker
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