From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758627AbcFAPpb (ORCPT ); Wed, 1 Jun 2016 11:45:31 -0400 Received: from mail-yw0-f196.google.com ([209.85.161.196]:35115 "EHLO mail-yw0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753077AbcFAPpa (ORCPT ); Wed, 1 Jun 2016 11:45:30 -0400 Date: Wed, 1 Jun 2016 11:45:27 -0400 From: Tejun Heo To: Bhaktipriya Shridhar Cc: Boris Ostrovsky , David Vrabel , Juergen Gross , Konrad Rzeszutek Wilk , Jan Beulich , Stefano Stabellini , Paul Gortmaker , Doug Goldstein , xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] xen: xen-pciback: Remove create_workqueue Message-ID: <20160601154527.GC14868@mtj.duckdns.org> References: <20160601141508.GA27853@Karyakshetra> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160601141508.GA27853@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 Wed, Jun 01, 2016 at 07:45:08PM +0530, Bhaktipriya Shridhar wrote: > System workqueues have been able to handle high level of concurrency > for a long time now and there's no reason to use dedicated workqueues > just to gain concurrency. Replace dedicated xen_pcibk_wq with the > use of system_wq. > > Unlike a dedicated per-cpu workqueue created with create_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 guarantees unless the target CPU is > explicitly specified and thus the increase of local concurrency shouldn't > make any difference. > > Since the work items could be pending, flush_work() has been used in > xen_pcibk_disconnect(). xen_pcibk_xenbus_remove() calls free_pdev() > which in turn calls xen_pcibk_disconnect() for every pdev to ensure that > there is no pending task while disconnecting the driver. > > Signed-off-by: Bhaktipriya Shridhar Acked-by: Tejun Heo Thanks. -- tejun