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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

  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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