From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-pf0-f173.google.com ([209.85.192.173]:34658 "EHLO mail-pf0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751112AbcGLRyh (ORCPT ); Tue, 12 Jul 2016 13:54:37 -0400 Date: Tue, 12 Jul 2016 13:54:34 -0400 From: Tejun Heo To: Bhaktipriya Shridhar Cc: Hans de Goede , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] zc3xx: Remove deprecated create_singlethread_workqueue Message-ID: <20160712175434.GP3190@htj.duckdns.org> References: <20160709075229.GA8020@Karyakshetra> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160709075229.GA8020@Karyakshetra> Sender: linux-media-owner@vger.kernel.org List-ID: On Sat, Jul 09, 2016 at 01:22:29PM +0530, Bhaktipriya Shridhar wrote: > The workqueue "work_thread" is involved in updating parameters for > transfers. It has a single work item(&sd->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. > > Work item has been flushed in sd_stop0() to ensure that there are no > pending tasks while disconnecting the driver. > > Signed-off-by: Bhaktipriya Shridhar Acked-by: Tejun Heo Thanks. -- tejun