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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4FA1BCCA473 for ; Mon, 13 Jun 2022 02:55:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234975AbiFMCzS (ORCPT ); Sun, 12 Jun 2022 22:55:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60782 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234440AbiFMCzQ (ORCPT ); Sun, 12 Jun 2022 22:55:16 -0400 Received: from mail-pj1-x102d.google.com (mail-pj1-x102d.google.com [IPv6:2607:f8b0:4864:20::102d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C91C3A191; Sun, 12 Jun 2022 19:55:16 -0700 (PDT) Received: by mail-pj1-x102d.google.com with SMTP id gc3-20020a17090b310300b001e33092c737so4676243pjb.3; Sun, 12 Jun 2022 19:55:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=t63caDtqr0AA//ZoM6eXOV7nTgEroVQihZDmmTAtOVw=; b=SpagrkUXR/0al8kxNb16RlzUwSttPdjODwumZyEug/IOxk77Wn3Mi8YIPGQuBDv6L+ lPnw5bIkZo9WIWVuvxnsjSvVEt0o/w2h1Keu5u96Alig1OhlrcF+ojdSI/rJ18fPQlY6 j5580adTKoAazBnfc3pCQ9rgnGTtlEdteIEGIZrm9GX6xEnTDiJ/eXt83zzXQibzkvFB iVt8NUhYWbVqXm5CBAzcjQOHnnkhQa/50EzdPjrJu9q50uv7ZO6g1v9JwyNxeq4cJaNE 9obhx4drondnrlUNw+oYqt7+JVVSuSIhjwy/DN5JzDKAMdIvNGfsXGytooH4DpRDAQP1 kFlA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=t63caDtqr0AA//ZoM6eXOV7nTgEroVQihZDmmTAtOVw=; b=4Ly7QcP2WTbojCxpdhE0q4Ha6zaWLbQmLWz3W9wzCi4ldGwijVjtNoSo+q+rqd0lhp XtgDeMr4xyWAKr37VyjTtHe+8qwJxdvBpJx9Dh8n+qW0EHFxTVeeGvgYRVpISeUPmPfu Gtj5KSDvxBJYe9YvudrQvmxvodIV+HxFYyTYAgtSK8Hfy5F20kHVpj/aWS6Lx+PGD6uK DUB4m+w71v58KRa2FTQHM7xhy7Dio3kkiN/vPfAQr9lYv7m10smpKICkZpUql1Uty1hB 0R5M107mNZ1K2MiaVEQm8pOzU+6Lt+i6YKjX9h9YMS8xqiExO361f+kDCjd9hXX3y3uO eQqA== X-Gm-Message-State: AOAM533NGpfaC2sVJMq0mWjQNZjy3UQajzGU/nZsHabhP8/30buOekV3 YUZpcLryZnWn0xWFS7Df6SE= X-Google-Smtp-Source: ABdhPJwiUya3EKqMLlP/HHRgy3rdluqQnxbx6tfBKcnyVjxv2c61PgpP3hdOjzmg/SN7/VLEj/BMDw== X-Received: by 2002:a17:902:e80a:b0:166:3a24:4572 with SMTP id u10-20020a170902e80a00b001663a244572mr56258220plg.30.1655088915565; Sun, 12 Jun 2022 19:55:15 -0700 (PDT) Received: from localhost (2603-800c-1a02-1bae-a7fa-157f-969a-4cde.res6.spectrum.com. [2603:800c:1a02:1bae:a7fa:157f:969a:4cde]) by smtp.gmail.com with ESMTPSA id ft23-20020a17090b0f9700b001e2bd411079sm6065972pjb.20.2022.06.12.19.55.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Jun 2022 19:55:15 -0700 (PDT) Sender: Tejun Heo Date: Sun, 12 Jun 2022 16:55:13 -1000 From: Tejun Heo To: Waiman Long Cc: Zefan Li , Johannes Weiner , Jonathan Corbet , Shuah Khan , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrew Morton , Roman Gushchin , Phil Auld , Peter Zijlstra , Juri Lelli , Frederic Weisbecker , Marcelo Tosatti , Michal =?iso-8859-1?Q?Koutn=FD?= Subject: Re: [PATCH v11 3/8] cgroup/cpuset: Allow no-task partition to have empty cpuset.cpus.effective Message-ID: References: <20220510153413.400020-1-longman@redhat.com> <20220510153413.400020-4-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Jun 12, 2022 at 10:53:53PM -0400, Waiman Long wrote: > Without this patch, cpus.effective will never be empty. It just falls back > to its parent if it becomes empty. Now with an empty cpus.effective, I am Yeah, that part is fine. > afraid that if a task is somehow moved to such a cpuset, something bad may > happen. So I add this check as a safeguard. But how would that happen? A lot of other things would break too if that were to happen. Thanks. -- tejun