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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 93E92C6786E for ; Fri, 26 Oct 2018 08:50:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A7DA2082D for ; Fri, 26 Oct 2018 08:50:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="RtxI3C4Y" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A7DA2082D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726549AbeJZRZ7 (ORCPT ); Fri, 26 Oct 2018 13:25:59 -0400 Received: from merlin.infradead.org ([205.233.59.134]:60424 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726096AbeJZRZ7 (ORCPT ); Fri, 26 Oct 2018 13:25:59 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Dqf5Ck5G8GYPCVzecdaI2lG/tCscd/Epzbc+OFt1exs=; b=RtxI3C4Y9eNwtNB5aJbArNPLX PPmMH7vhAWHJgIYsFvO0bx1BCDzhrUc7aZfj8zhW2vb2ehVnXS/BeGXNROmVnlyjK4pOGlGydS0/V dgJuBGAukHs0C2xcwcsKSq4e0VyIQMcfcMzqXnitSrJWJxfp6LNJmcGCHJnCxFXU7KkA0mn1vqYOY jci9lxiFzSNt6zBVwzNmowXG0TRNL/oXtsLau4bKLJ7HHbsp/pvnWHHsHmlX2mM1zJs6x56qTT2gF 1xkxuH0wkqnEpONYWTSPPDcwHnEZvRG8bNKT5HQc6GySI4Hmi6+mvRd9Y5LdfxGY7Wl6zDSWNtwRr d5P7QE5Aw==; Received: from [167.98.65.38] (helo=worktop) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gFxoN-0000yr-UH; Fri, 26 Oct 2018 08:49:44 +0000 Received: by worktop (Postfix, from userid 1000) id 3C3336E07D9; Fri, 26 Oct 2018 10:42:55 +0200 (CEST) Date: Fri, 26 Oct 2018 10:42:55 +0200 From: Peter Zijlstra To: Srikar Dronamraju Cc: Ingo Molnar , LKML , Mel Gorman , Rik van Riel , Yi Wang , zhong.weidong@zte.com.cn, Yi Liu , Frederic Weisbecker , Thomas Gleixner Subject: Re: [PATCH v2] sched/core: Don't mix isolcpus and housekeeping CPUs Message-ID: <20181026084255.GZ3109@worktop.c.hoisthospitality.com> References: <1540350169-18581-1-git-send-email-srikar@linux.vnet.ibm.com> <20181024100323.GO3109@worktop.c.hoisthospitality.com> <20181024103002.GB18466@linux.vnet.ibm.com> <20181025000707.GR3109@worktop.c.hoisthospitality.com> <20181025182317.GE18466@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181025182317.GE18466@linux.vnet.ibm.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 25, 2018 at 11:53:17PM +0530, Srikar Dronamraju wrote: > > > > You can create multiple partitions with cpusets but still have an > > unbound task in the root cgroup. That would suffer the exact same > > problems. > > > > I probably don't understand this. Even if the child cgroups has > cpu_exclusive or sched_load_balance reset, the tasks in root cgroup has > access to all cpus in system. Right? The crucial word being 'access'. The root group will not impose a limit on the affinity of tasks. So you can indeed have affinities that span load balancing domains. And yes, that leads to 'interesting' but specified behaviour.