From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751319AbcGLSoj (ORCPT ); Tue, 12 Jul 2016 14:44:39 -0400 Received: from mail-pa0-f65.google.com ([209.85.220.65]:35351 "EHLO mail-pa0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750999AbcGLSoh (ORCPT ); Tue, 12 Jul 2016 14:44:37 -0400 Date: Tue, 12 Jul 2016 14:44:34 -0400 From: Tejun Heo To: Bhaktipriya Shridhar Cc: Mark Brown , linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] spi: spi-sh: Remove deprecated create_singlethread_workqueue Message-ID: <20160712184434.GE3190@htj.duckdns.org> References: <201607021811.Q9yqxNLJ%fengguang.wu@intel.com> <1468160719-32600-1-git-send-email-bhaktipriya96@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1468160719-32600-1-git-send-email-bhaktipriya96@gmail.com> 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 Sun, Jul 10, 2016 at 07:55:19PM +0530, Bhaktipriya Shridhar wrote: > The workqueue has a single workitem(&ss->ws) 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 spi_sh_remove() to ensure that > there are no pending tasks while disconnecting the driver. > > Signed-off-by: Bhaktipriya Shridhar Acked-by: Tejun Heo Thanks. -- tejun From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH v2] spi: spi-sh: Remove deprecated create_singlethread_workqueue Date: Tue, 12 Jul 2016 14:44:34 -0400 Message-ID: <20160712184434.GE3190@htj.duckdns.org> References: <201607021811.Q9yqxNLJ%fengguang.wu@intel.com> <1468160719-32600-1-git-send-email-bhaktipriya96@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Mark Brown , linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Bhaktipriya Shridhar Return-path: Content-Disposition: inline In-Reply-To: <1468160719-32600-1-git-send-email-bhaktipriya96-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: On Sun, Jul 10, 2016 at 07:55:19PM +0530, Bhaktipriya Shridhar wrote: > The workqueue has a single workitem(&ss->ws) 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 spi_sh_remove() to ensure that > there are no pending tasks while disconnecting the driver. > > Signed-off-by: Bhaktipriya Shridhar Acked-by: Tejun Heo Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html