From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752612AbcGRXyL (ORCPT ); Mon, 18 Jul 2016 19:54:11 -0400 Received: from mail-pf0-f193.google.com ([209.85.192.193]:36204 "EHLO mail-pf0-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752585AbcGRXyH (ORCPT ); Mon, 18 Jul 2016 19:54:07 -0400 Date: Mon, 18 Jul 2016 19:53:52 -0400 From: Tejun Heo To: Bhaktipriya Shridhar Cc: Frank Zago , Hans de Goede , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [media] gspca: finepix: Remove deprecated create_singlethread_workqueue Message-ID: <20160718235352.GW3078@mtj.duckdns.org> References: <20160716085556.GA7841@Karyakshetra> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160716085556.GA7841@Karyakshetra> User-Agent: Mutt/1.6.1 (2016-04-27) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 16, 2016 at 02:25:56PM +0530, Bhaktipriya Shridhar wrote: > The workqueue "work_thread" is involved in streaming the camera data. > It has a single work item(&dev->work_struct) 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