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=-12.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,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 E2264C388F9 for ; Thu, 19 Nov 2020 11:07:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77907246F0 for ; Thu, 19 Nov 2020 11:07:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="oOTfAO/e" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726821AbgKSLGx (ORCPT ); Thu, 19 Nov 2020 06:06:53 -0500 Received: from mail.kernel.org ([198.145.29.99]:33204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726811AbgKSLGx (ORCPT ); Thu, 19 Nov 2020 06:06:53 -0500 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CFB2522248; Thu, 19 Nov 2020 11:06:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605784013; bh=b8cCQkCQy5W7ziGXPmOkx0Jd36itvYN1twVbH+66fBo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=oOTfAO/eWZincc5ZJR4RbQaf9A7bNYPCEj71/S73O083IgI42moMXcQSz2+X46rSX HyNg0E5wSn6Q/8+yutHMRSZDE2E6YHlF9XCFxLzPD7Ph2z6vTW435lOlqvz/h5uFb/ Gdnh7NveJdyAfAjj/P1z7ak4oJNUcU1mbfUQdrZs= Date: Thu, 19 Nov 2020 11:06:45 +0000 From: Will Deacon To: Quentin Perret Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , Tejun Heo , Li Zefan , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , kernel-team@android.com Subject: Re: [PATCH v3 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Message-ID: <20201119110645.GC3946@willie-the-truck> References: <20201113093720.21106-1-will@kernel.org> <20201113093720.21106-10-will@kernel.org> <20201119092922.GC2416649@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201119092922.GC2416649@google.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Thu, Nov 19, 2020 at 09:29:22AM +0000, Quentin Perret wrote: > On Friday 13 Nov 2020 at 09:37:14 (+0000), Will Deacon wrote: > > If the scheduler cannot find an allowed CPU for a task, > > cpuset_cpus_allowed_fallback() will widen the affinity to cpu_possible_mask > > if cgroup v1 is in use. > > > > In preparation for allowing architectures to provide their own fallback > > mask, just return early if we're not using cgroup v2 and allow > > select_fallback_rq() to figure out the mask by itself. > > > > Cc: Li Zefan > > Cc: Tejun Heo > > Cc: Johannes Weiner > > Signed-off-by: Will Deacon > > That makes select_fallback_rq() slightly more expensive if you're using > cgroup v1, but I don't expect that be really measurable in real-world > workloads, so: > > Reviewed-by: Quentin Perret Cheers! Will