From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55E2BC433DB for ; Wed, 23 Dec 2020 19:50:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 19C5722482 for ; Wed, 23 Dec 2020 19:50:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728395AbgLWTud (ORCPT ); Wed, 23 Dec 2020 14:50:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:35650 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726384AbgLWTud (ORCPT ); Wed, 23 Dec 2020 14:50:33 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2503B223E4; Wed, 23 Dec 2020 19:49:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1608752992; bh=woprWZFTS6K4LJCyz89cuszr5XvTqwSkumbI3YKeqrc=; h=Date:From:To:Cc:Subject:Reply-To:References:In-Reply-To:From; b=TRfWrRCvKL3EwxvsXI3iP8/Bhi9gdkuSZW5Xh6Ru1gYVZUgb22yv1iaUmKsUUKOZB CjmGQF5754EoTtIBd5wvSnWcTzZqfFot1DX+epOnPE0h/9W3UNopWg5nTu8MfnuRPS wqXVnRKl8kM6IyKX8Hni66vvYdwLkP9Ep6WqRmM53ifmdZh4BtdnbMCxqMYSqDAjkv o2Q365+JhpSevQRk1++pXWEiasIMbkcd9ho82LCp6WJthTZ02oOVUMvra0JDq8ZUSr WMlj0BqPd+1HIapox3+EHV0Wrsl2TYPsJqb5DR1nZuKKoPqPOximkdgjHWefR0X1zm ZLbn1zC6I1EuA== Received: by paulmck-ThinkPad-P72.home (Postfix, from userid 1000) id DBB3D3522E72; Wed, 23 Dec 2020 11:49:51 -0800 (PST) Date: Wed, 23 Dec 2020 11:49:51 -0800 From: "Paul E. McKenney" To: Lai Jiangshan Cc: linux-kernel@vger.kernel.org, Valentin Schneider , Peter Zijlstra , Qian Cai , Vincent Donnefort , Lai Jiangshan , Hillf Danton , Tejun Heo Subject: Re: [PATCH -tip V2 00/10] workqueue: break affinity initiatively Message-ID: <20201223194951.GA10044@paulmck-ThinkPad-P72> Reply-To: paulmck@kernel.org References: <20201218170919.2950-1-jiangshanlai@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201218170919.2950-1-jiangshanlai@gmail.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Dec 19, 2020 at 01:09:09AM +0800, Lai Jiangshan wrote: > From: Lai Jiangshan > > 06249738a41a ("workqueue: Manually break affinity on hotplug") > said that scheduler will not force break affinity for us. > > But workqueue highly depends on the old behavior. Many parts of the codes > relies on it, 06249738a41a ("workqueue: Manually break affinity on hotplug") > is not enough to change it, and the commit has flaws in itself too. > > It doesn't handle for worker detachment. > It doesn't handle for worker attachement, mainly worker creation > which is handled by Valentin Schneider's patch [1]. > It doesn't handle for unbound workers which might be possible > per-cpu-kthread. > > We need to thoroughly update the way workqueue handles affinity > in cpu hot[un]plug, what is this patchset intends to do and > replace the Valentin Schneider's patch [1]. The equivalent patch > is patch 10. > > Patch 1 fixes a flaw reported by Hillf Danton . > I have to include this fix because later patches depends on it. > > The patchset is based on tip/master rather than workqueue tree, > because the patchset is a complement for 06249738a41a ("workqueue: > Manually break affinity on hotplug") which is only in tip/master by now. > > And TJ acked to route the series through tip. > > Changed from V1: > Add TJ's acked-by for the whole patchset > > Add more words to the comments and the changelog, mainly derived > from discussion with Peter. > > Update the comments as TJ suggested. > > Update a line of code as Valentin suggested. > > Add Valentin's ack for patch 10 because "Seems alright to me." and > add Valentin's comments to the changelog which is integral. > > [1]: https://lore.kernel.org/r/ff62e3ee994efb3620177bf7b19fab16f4866845.camel@redhat.com > [V1 patcheset]: https://lore.kernel.org/lkml/20201214155457.3430-1-jiangshanlai@gmail.com/ > > Cc: Hillf Danton > Cc: Valentin Schneider > Cc: Qian Cai > Cc: Peter Zijlstra > Cc: Vincent Donnefort > Cc: Tejun Heo And rcutorture hits this, so thank you for the fix! Tested-by: Paul E. McKenney > Lai Jiangshan (10): > workqueue: restore unbound_workers' cpumask correctly > workqueue: use cpu_possible_mask instead of cpu_active_mask to break > affinity > workqueue: Manually break affinity on pool detachment > workqueue: don't set the worker's cpumask when kthread_bind_mask() > workqueue: introduce wq_online_cpumask > workqueue: use wq_online_cpumask in restore_unbound_workers_cpumask() > workqueue: Manually break affinity on hotplug for unbound pool > workqueue: reorganize workqueue_online_cpu() > workqueue: reorganize workqueue_offline_cpu() unbind_workers() > workqueue: Fix affinity of kworkers when attaching into pool > > kernel/workqueue.c | 214 ++++++++++++++++++++++++++++----------------- > 1 file changed, 132 insertions(+), 82 deletions(-) > > -- > 2.19.1.6.gb485710b >