From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935154AbcHaOYU (ORCPT ); Wed, 31 Aug 2016 10:24:20 -0400 Received: from mail-yw0-f195.google.com ([209.85.161.195]:34827 "EHLO mail-yw0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933214AbcHaOYS (ORCPT ); Wed, 31 Aug 2016 10:24:18 -0400 Date: Wed, 31 Aug 2016 10:24:16 -0400 From: Tejun Heo To: Bhaktipriya Shridhar Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org Subject: Re: [PATCH] device core: Remove deprecated create_singlethread_workqueue Message-ID: <20160831142416.GK12660@htj.duckdns.org> References: <20160830171534.GA1917@Karyakshetra> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160830171534.GA1917@Karyakshetra> User-Agent: Mutt/1.7.0 (2016-08-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 30, 2016 at 10:45:34PM +0530, Bhaktipriya Shridhar wrote: > The workqueue "deferred_wq" queues a single work item > &deferred_probe_work and hence doesn't require ordering. > It is involved in probing devices and is not being used on a memory > reclaim path. Hence, it has been converted to use 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. > > The work item has been flushed in driver_probe_done() to ensure that > there are no pending tasks while disconnecting the driver. > > Signed-off-by: Bhaktipriya Shridhar Acked-by: Tejun Heo Thanks. -- tejun