From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Marco Crivellari <marco.crivellari@suse.com>
Cc: linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org,
Tejun Heo <tj@kernel.org>, Lai Jiangshan <jiangshanlai@gmail.com>,
Frederic Weisbecker <frederic@kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Michal Hocko <mhocko@suse.com>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>
Subject: Re: [RFC PATCH v2] usb: typec: ucsi: Move long delayed work on system_dfl_long_wq
Date: Fri, 22 May 2026 10:37:51 +0200 [thread overview]
Message-ID: <2026052234-rejoicing-agreeably-0fc5@gregkh> (raw)
In-Reply-To: <20260508143853.330151-1-marco.crivellari@suse.com>
On Fri, May 08, 2026 at 04:38:53PM +0200, Marco Crivellari wrote:
> Currently the code enqueue work items using {queue|mod}_delayed_work(),
> using system_long_wq. This workqueue should be used when long works are
> expected and it is a per-cpu workqueue.
>
> The function(s) end up calling __queue_delayed_work(), which set a global
> timer that could fire anywhere, enqueuing the work where the timer fired.
>
> Unbound works could benefit from scheduler task placement, to optimize
> performance and power consumption. Long work shouldn't stick to a single
> CPU.
>
> Recently, a new unbound workqueue specific for long running work has
> been added:
>
> c116737e972e ("workqueue: Add system_dfl_long_wq for long unbound works")
>
> Since the workqueue work doesn't rely on per-cpu variables, there is no
> obvious reason that justify the use of a per-cpu workqueue. So change
> system_long_wq with system_dfl_long_wq so that the work may benefit from
> scheduler task placement.
>
> Signed-off-by: Marco Crivellari <marco.crivellari@suse.com>
> ---
> Changes in v2:
> - Fixed a wrong change regarding system_long_wq used by queue_work() instead of queue_delayed_work()
>
> Link to v1: https://lore.kernel.org/all/20260507142726.331206-1-marco.crivellari@suse.com/
What "comments" do you need resolved here before submitting this as a
real patch?
thanks,
greg k-h
next prev parent reply other threads:[~2026-05-22 8:37 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-08 14:38 [RFC PATCH v2] usb: typec: ucsi: Move long delayed work on system_dfl_long_wq Marco Crivellari
2026-05-19 9:01 ` Marco Crivellari
2026-05-19 13:56 ` Heikki Krogerus
2026-05-22 8:37 ` Greg Kroah-Hartman [this message]
2026-05-22 9:27 ` Marco Crivellari
2026-05-22 9:31 ` Greg Kroah-Hartman
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