From patchwork Fri Mar 17 15:15:07 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 13179202 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 32674C74A5B for ; Fri, 17 Mar 2023 15:16:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231697AbjCQPQw (ORCPT ); Fri, 17 Mar 2023 11:16:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44088 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231752AbjCQPQn (ORCPT ); Fri, 17 Mar 2023 11:16:43 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CCD2F6B5C6 for ; Fri, 17 Mar 2023 08:15:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679066135; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=xGXOF5DEcP6pwvx1eYY/0gGWQNDYbTOSJx5veuAvjus=; b=c1RRVw1pITr3l1jTRSK/jsvuWpTOtgk78Ei7Ggt0lzo9rvbZ+bHGoU94KcG+l8hIjP1/9M VyHwL6idgAvk4rKkvq/ZZPmeEhOHe6VJYFPWc/rnvQG9tqJTfEv/0DtaRqW65MMWMEaB1n y7h+xx8UOmsY02tg8Fctl17S25apBM0= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-269-KPwhbz6AN9y_PYfmsIre9w-1; Fri, 17 Mar 2023 11:15:31 -0400 X-MC-Unique: KPwhbz6AN9y_PYfmsIre9w-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 12C7E3C10246; Fri, 17 Mar 2023 15:15:31 +0000 (UTC) Received: from llong.com (unknown [10.22.10.238]) by smtp.corp.redhat.com (Postfix) with ESMTP id 924D6492B00; Fri, 17 Mar 2023 15:15:30 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner , Shuah Khan Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Will Deacon , Peter Zijlstra , =?utf-8?q?Michal_Koutn=C3=BD?= , Juri Lelli , Waiman Long Subject: [PATCH v2 3/4] cgroup/cpuset: Include offline CPUs when tasks' cpumasks in top_cpuset are updated Date: Fri, 17 Mar 2023 11:15:07 -0400 Message-Id: <20230317151508.1225282-4-longman@redhat.com> In-Reply-To: <20230317151508.1225282-1-longman@redhat.com> References: <20230317151508.1225282-1-longman@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Similar to commit 3fb906e7fabb ("group/cpuset: Don't filter offline CPUs in cpuset_cpus_allowed() for top cpuset tasks"), the whole set of possible CPUs including offline ones should be used for setting cpumasks for tasks in the top cpuset when a cpuset partition is modified as the hotplug code won't update cpumasks for tasks in the top cpuset when CPUs become online or offline. Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 23 ++++++++++++++--------- 1 file changed, 14 insertions(+), 9 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 5b8d763555b0..db8793a2082f 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1209,7 +1209,9 @@ void rebuild_sched_domains(void) * * Iterate through each task of @cs updating its cpus_allowed to the * effective cpuset's. As this function is called with cpuset_rwsem held, - * cpuset membership stays stable. + * cpuset membership stays stable. For top_cpuset, task_cpu_possible_mask() + * is used instead of effective_cpus to make sure all offline CPUs are also + * included as hotplug code won't update cpumasks for tasks in top_cpuset. */ static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus) { @@ -1219,15 +1221,18 @@ static void update_tasks_cpumask(struct cpuset *cs, struct cpumask *new_cpus) css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it))) { - /* - * Percpu kthreads in top_cpuset are ignored - */ - if (top_cs && (task->flags & PF_KTHREAD) && - kthread_is_per_cpu(task)) - continue; + const struct cpumask *possible_mask = task_cpu_possible_mask(task); - cpumask_and(new_cpus, cs->effective_cpus, - task_cpu_possible_mask(task)); + if (top_cs) { + /* + * Percpu kthreads in top_cpuset are ignored + */ + if ((task->flags & PF_KTHREAD) && kthread_is_per_cpu(task)) + continue; + cpumask_andnot(new_cpus, possible_mask, cs->subparts_cpus); + } else { + cpumask_and(new_cpus, possible_mask, cs->effective_cpus); + } set_cpus_allowed_ptr(task, new_cpus); } css_task_iter_end(&it);