linux-kernel - Re: [PATCH 2/3] Input: touchscreen: mc13783_ts: Remove deprecated create_singletheread

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Date:	Mon, 15 Aug 2016 18:53:59 -0400
From:	Tejun Heo <tj@...nel.org>
To:	Bhaktipriya Shridhar <bhaktipriya96@...il.com>
Cc:	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Hans de Goede <hdegoede@...hat.com>,
	Pali Rohár <pali.rohar@...il.com>,
	Chris Diamand <chris@...mand.org>,
	Stefan Assmann <sassmann@...nic.de>,
	Richard Pospesel <pospeselr@...il.com>,
	Lars-Peter Clausen <lars@...afoo.de>,
	Takashi Iwai <tiwai@...e.de>,
	patches@...nsource.wolfsonmicro.com, linux-input@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] Input: touchscreen: mc13783_ts:  Remove deprecated
 create_singletheread_workqueue

On Sun, Aug 14, 2016 at 10:55:30AM +0530, Bhaktipriya Shridhar wrote:
> The workqueue "workqueue" has a single workitem(&priv->work) and hence
> doesn't require ordering. Also, it is not being used on a memory reclaim
> path. Hence, the singlethreaded workqueue has been replaced with the use
> of system_wq.
> 
> System workqueues have been able to handle high level of concurrency
> for a long time now and hence it's not required to have a singlethreaded
> workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
> created with create_singlethread_workqueue(), system_wq allows multiple
> work items to overlap executions even on the same CPU; however, a
> per-cpu workqueue doesn't have any CPU locality or global ordering
> guarantee unless the target CPU is explicitly specified and thus the
> increase of local concurrency shouldn't make any difference.
> 
> Workitem is sync cancelled in mc13783_ts_remove() to ensure that there
> are no workitems pending when the driver is disconnected.
> 
> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@...il.com>

Acked-by: Tejun Heo <tj@...nel.org>

Thanks.

-- 
tejun