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=-5.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_MUTT 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 1F1BCC31E46 for ; Wed, 12 Jun 2019 18:02:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E884020684 for ; Wed, 12 Jun 2019 18:02:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1560362562; bh=EAaesGnfmiZs7tHX6Vea1rVf/xE253R5d4n2Qb7gbH4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=gix507EKWOdMV5Cb8JngA1iY3g2YPaYxWngqexQ/TlclK9LRuvOimjD/HiX1uv9/f ytcCQLYJybT4FE47QMGgchxQ62sjE/0tWryd9oDFtr079SFDzmb3tMPaTYpMAREPCJ BG2UFtflPmgf7Jo+CpEiPSe8Z50vXj0cF9e80JsY= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729232AbfFLSCl (ORCPT ); Wed, 12 Jun 2019 14:02:41 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:37729 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728040AbfFLSCk (ORCPT ); Wed, 12 Jun 2019 14:02:40 -0400 Received: by mail-pf1-f195.google.com with SMTP id 19so9289535pfa.4; Wed, 12 Jun 2019 11:02:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=5+frD1W0PaRHYVfg7bRlg/bAjJXsZpY3XnMe0SfDiS8=; b=DPUHU1je3wTkpwlmd4MDNQvT6dUdwrfcgO9977+0I6QZnpSQ06GQLLwWKQDu8JQL4e A0s6M+ym0+M2+9lOyg+uLIrUhDvUczKtO7PPnpDIuDx6v1EjhQlNbLMifAD7wHFAjOEz SFXRSfsnlETmOJAxvMO7pxUVw8jsxiGVvps9/8pjqDShlbA7FHSvsdbq7m76wH5eV/O4 6ANvVXTPseOZh3bv4kS9RMlv6PAddZOy135SEKfAITFTRQUBhrZeexigSL9EMMPI5KAW i5rZwS18NdwBeTZkhL+ZXrYsTmp6PkS4RxsEhYKDrRm6mC5ZD2TGpxTUnjDwgDytUWJM 9LKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=5+frD1W0PaRHYVfg7bRlg/bAjJXsZpY3XnMe0SfDiS8=; b=r3HySzIMTlMRq7SYaenjrcl4baVOZSzLa4nqvWLn3P+NEgLXHE0shFnzzL1va6XPso MRwGWRD5Jga5nkvlzsxq9XI0z3buMH9rEUMbFQPN+1O55S3oJJ710hiS9mGLbldHVIcW MM9GwwMEDe1iTjpRGC+0FGCj/+oiEBO2uX85g+QMcn3Ww8kcLB8SjquTESex1aX3qQqe MoY2/J+drkOIC0ySAoN/cWIGg8FYZq91M4PQ1BcfykwCHWYD9FaKAsdcouhx6LwPPE2p N5GuJecAihUDS/jE6ADf6TaA/JFWyHQUATFR2HmegKwxiXrj4iPxh15s0TvWLI4LEIO5 pR/Q== X-Gm-Message-State: APjAAAXHKem/xVGREo5RDnMU50Ipy1xcTIc0XbdgPL3tEnNTvKsjwyqP kZ64TOD/9DxMQQEAB3Ks1CE= X-Google-Smtp-Source: APXvYqwae3ax93KZBruArMl2KQTDH37C9xXhwO6pqxhbJI70VmY7WfvIA2jEavLoCOMpZlxYqYsIWQ== X-Received: by 2002:a17:90a:718c:: with SMTP id i12mr502752pjk.32.1560362559537; Wed, 12 Jun 2019 11:02:39 -0700 (PDT) Received: from localhost ([2620:10d:c091:500::c431]) by smtp.gmail.com with ESMTPSA id s5sm127486pji.9.2019.06.12.11.02.38 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 12 Jun 2019 11:02:38 -0700 (PDT) Date: Wed, 12 Jun 2019 11:02:36 -0700 From: Tejun Heo To: Joel Savitz Cc: linux-kernel@vger.kernel.org, Li Zefan , Phil Auld , Waiman Long , Michal =?iso-8859-1?Q?Koutn=FD?= , Ingo Molnar , Peter Zijlstra , cgroups@vger.kernel.org Subject: Re: [RESEND PATCH v3] cpuset: restore sanity to cpuset_cpus_allowed_fallback() Message-ID: <20190612180236.GQ3341036@devbig004.ftw2.facebook.com> References: <1560354648-23632-1-git-send-email-jsavitz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1560354648-23632-1-git-send-email-jsavitz@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jun 12, 2019 at 11:50:48AM -0400, Joel Savitz wrote: > In the case that a process is constrained by taskset(1) (i.e. > sched_setaffinity(2)) to a subset of available cpus, and all of those are > subsequently offlined, the scheduler will set tsk->cpus_allowed to > the current value of task_cs(tsk)->effective_cpus. > > This is done via a call to do_set_cpus_allowed() in the context of > cpuset_cpus_allowed_fallback() made by the scheduler when this case is > detected. This is the only call made to cpuset_cpus_allowed_fallback() > in the latest mainline kernel. > > However, this is not sane behavior. ... > Suggested-by: Waiman Long > Suggested-by: Phil Auld > Signed-off-by: Joel Savitz Applied to cgroup/for-5.2-fixes. Thanks. -- tejun