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=-7.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE autolearn=no 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 AFD06C07E9B for ; Mon, 19 Jul 2021 13:17:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 92CDD60C41 for ; Mon, 19 Jul 2021 13:17:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237310AbhGSMga (ORCPT ); Mon, 19 Jul 2021 08:36:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:60758 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237271AbhGSMg0 (ORCPT ); Mon, 19 Jul 2021 08:36:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 5185A610A5; Mon, 19 Jul 2021 13:17:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626700626; bh=mNX83eIS2g05s9c9QnvJuS5+XyJQcbNL2BxYEIAFG0s=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=F9A/Q5smYmjuQAy1aDH4g5YIn755qVr2mQiHtfOUV7c8AMx0jyiX3tXLmSPhjtEAY 3kQ/6BuMJ6AYy6tFq6tWDieOy1qdL2Eg/EN2lqJ+zuerXQyIeVRPyiOmc3zOKfNyyr rOpScydKnA5BCj+XkQZWhg2sQvmVE7b1Ihu+C5akwuH8TRtG60N8/zzEMvRiPt8JFU QrLvz3sGawj0+L2zC7ppVmE4KQmDulCVYqW7vrbFc+cN3cONMwzHmChhpDgvPp596M SXKdnQStzGqVti/mOQ1woOUr0eG4PMUE8U9OH3eatVGFlVgb4TGo2utnPrISDmpUIq 3Iw7qFIypkJZg== Date: Mon, 19 Jul 2021 15:17:04 +0200 From: Frederic Weisbecker To: Peter Zijlstra Cc: Valentin Schneider , LKML , Tejun Heo , Juri Lelli , Alex Belits , Nitesh Lal , Thomas Gleixner , Nicolas Saenz , Christoph Lameter , Marcelo Tosatti , Zefan Li , cgroups@vger.kernel.org Subject: Re: [RFC PATCH 6/6] cpuset: Add cpuset.isolation_mask file Message-ID: <20210719131704.GA116346@lothringen> References: <20210714135420.69624-1-frederic@kernel.org> <20210714135420.69624-7-frederic@kernel.org> <20210714231338.GA65963@lothringen> <20210715090419.GH2725@worktop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210715090419.GH2725@worktop.programming.kicks-ass.net> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jul 15, 2021 at 11:04:19AM +0200, Peter Zijlstra wrote: > On Thu, Jul 15, 2021 at 01:13:38AM +0200, Frederic Weisbecker wrote: > > On Wed, Jul 14, 2021 at 06:52:43PM +0200, Peter Zijlstra wrote: > > > > cpusets already has means to create paritions; why are you creating > > > something else? > > > > I was about to answer that the semantics of isolcpus, which reference > > a NULL domain, are different from SD_LOAD_BALANCE implied by > > cpuset.sched_load_balance. But then I realize that SD_LOAD_BALANCE has > > been removed. > > > > How cpuset.sched_load_balance is implemented then? Commit > > e669ac8ab952df2f07dee1e1efbf40647d6de332 ("sched: Remove checks against > > SD_LOAD_BALANCE") advertize that setting cpuset.sched_load_balance to 0 > > ends up creating NULL domain but that's not what I get. For example if I > > mount a single cpuset root (no other cpuset mountpoints): > > SD_LOAD_BALANCE was only for when you wanted to stop balancing inside a > domain tree. That no longer happens (and hasn't for a *long* time). > Cpusets simply creates multiple domain trees (or the empty one if its > just one CPU). Ok. > > > $ mount -t cgroup none ./cpuset -o cpuset > > $ cd cpuset > > $ cat cpuset.cpus > > 0-7 > > $ cat cpuset.sched_load_balance > > 1 > > $ echo 0 > cpuset.sched_load_balance > > $ ls /sys/kernel/debug/domains/cpu1/ > > domain0 domain1 > > > > I still get the domains on all CPUs... > > (note, that's the cgroup-v1 interface, the cgroup-v2 interface is > significantly different) > > I'd suggest doing: echo 1 > /debug/sched/verbose, if I do the above I > get: > > [1290784.889705] CPU0 attaching NULL sched-domain. > [1290784.894830] CPU1 attaching NULL sched-domain. Thanks! Eventually I uninstalled cgmanager and things seem to work now. I have no idea why and I'm not sure I'm willing to investigate further :o)