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 C2CE8CD37B4 for ; Sun, 17 Sep 2023 16:53:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236884AbjIQQww (ORCPT ); Sun, 17 Sep 2023 12:52:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51820 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237055AbjIQQwq (ORCPT ); Sun, 17 Sep 2023 12:52:46 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 943C4188 for ; Sun, 17 Sep 2023 09:51:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694969509; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=rgW2MUYlHHfdCZ+QdWezRlOQ9jHuf7PY43yzWv+wfSM=; b=GPuNjIfkACW5iU9yVzT97Wh0CvNk3ZW/aG6b3KQjaLMvGXXH69zf1MIKkKZBTA8sPWLH7r ZEWe4A53zkipDSkVFtbA6anraOSwoujcsMGB1BAhC/Gt9FnFJPTJfu5Jk5FGW9k4YNp1ZV n6D1o7jkhvJWZGZsVcQSwm8Iv7NSgy4= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-118-7D-EcRCMNxOI8vbd2BqiLg-1; Sun, 17 Sep 2023 12:51:44 -0400 X-MC-Unique: 7D-EcRCMNxOI8vbd2BqiLg-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 4F192945926; Sun, 17 Sep 2023 16:51:44 +0000 (UTC) Received: from [10.22.8.73] (unknown [10.22.8.73]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8C64110F1BE7; Sun, 17 Sep 2023 16:51:43 +0000 (UTC) Message-ID: <5e513c72-7198-a55e-6e2b-a811d5529284@redhat.com> Date: Sun, 17 Sep 2023 12:51:43 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.14.0 Subject: Re: [PATCH 1/1] cgroup/cpuset: Rebuild sched domains if isolated partition changed Content-Language: en-US To: Pierre Gondois , linux-kernel@vger.kernel.org Cc: rui.zhang@intel.com, aaron.lu@intel.com, Zefan Li , Tejun Heo , Johannes Weiner , cgroups@vger.kernel.org References: <20230915154505.363754-1-pierre.gondois@arm.com> <20230915154505.363754-2-pierre.gondois@arm.com> From: Waiman Long In-Reply-To: <20230915154505.363754-2-pierre.gondois@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 9/15/23 11:45, Pierre Gondois wrote: > When an isolated parition is created, the sched domains (sds) are > rebuilt and the sds of the isolated CPUs are detached. This only > happens at the creation of the isolated parition. Updating > the cpuset of the partition doesn't rebuild the sds: > > To reproduce: > # ls /sys/kernel/debug/sched/domains/cpu0/ > domain0 > # ls /sys/kernel/debug/sched/domains/cpu1/ > domain0 > # > # mkdir cgroup > # mount -t cgroup2 none cgroup/ > # mkdir cgroup/A1/ > # echo "+cpuset" > cgroup/cgroup.subtree_control > # echo 0-3 > cgroup/A1/cpuset.cpus > # echo isolated > cgroup/A1/cpuset.cpus.partition > # > # ls /sys/kernel/debug/sched/domains/cpu0/ > # ls /sys/kernel/debug/sched/domains/cpu1/ > # > # echo 0 > cgroup/A1/cpuset.cpus > # ls /sys/kernel/debug/sched/domains/cpu0/ > # ls /sys/kernel/debug/sched/domains/cpu1/ > # > > Here CPU1 should have a sched domain re-attached. > > Signed-off-by: Pierre Gondois > --- > kernel/cgroup/cpuset.c | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > index 58e6f18f01c1..e3eb27ff9b68 100644 > --- a/kernel/cgroup/cpuset.c > +++ b/kernel/cgroup/cpuset.c > @@ -1680,11 +1680,15 @@ static void update_cpumasks_hier(struct cpuset *cs, struct tmpmasks *tmp, > * empty cpuset is changed, we need to rebuild sched domains. > * On default hierarchy, the cpuset needs to be a partition > * root as well. > + * Also rebuild sched domains if the cpuset of an isolated > + * partition changed. > */ > - if (!cpumask_empty(cp->cpus_allowed) && > - is_sched_load_balance(cp) && > - (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || > - is_partition_valid(cp))) > + if ((!cpumask_empty(cp->cpus_allowed) && > + is_sched_load_balance(cp) && > + (!cgroup_subsys_on_dfl(cpuset_cgrp_subsys) || > + is_partition_valid(cp))) || > + (cp->partition_root_state == PRS_ISOLATED || > + cp->partition_root_state == PRS_INVALID_ISOLATED)) > need_rebuild_sched_domains = true; > > rcu_read_lock(); Thanks for spotting the problem and sending out a patch to fix it. However, it should be done in the update_cpumask(). The sched_domain rebuild in update_cpumasks_hier() is supposed to be used for impacted descendant cpusets lower down in the hierarchy. Anyway, I believe this problem should have been fixed in commit a86ce68078b2 ("cgroup/cpuset: Extract out CS_CPU_EXCLUSIVE & CS_SCHED_LOAD_BALANCE handling") recently merged into the v6.6 kernel. Would you mind testing the latest upstream kernel to see if this problem is gone or not? Thanks, Longman