From patchwork Mon Mar 6 20:08:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 660282 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 C3E61C61DA4 for ; Mon, 6 Mar 2023 20:10:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230202AbjCFUKS (ORCPT ); Mon, 6 Mar 2023 15:10:18 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50856 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230222AbjCFUKQ (ORCPT ); Mon, 6 Mar 2023 15:10:16 -0500 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 926D94C6DD for ; Mon, 6 Mar 2023 12:09:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678133370; 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=Grvm3WHWtWaUdwJ9Qfi2o/ztDJyGIgGXieKrU2ipubo=; b=U5NHjzv2APehYE7g/x0ZJ8mXQLxVjD0muk6iGgAY7Nrook/Zjpg0ikgdIxfS3fhMi6QKXb AC6YD9GnrvZ1umpG9wz0Cey5Ih+sQStTuoBoVgw2uMgYPyTXMp+Dt04dIo+unA20wJ4STG POuhVoJD+RmRFtrcnTE4aUaXIJbSwUo= 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-125-DbWfXIfcNhCArXncUlTaqg-1; Mon, 06 Mar 2023 15:09:27 -0500 X-MC-Unique: DbWfXIfcNhCArXncUlTaqg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 6617885A588; Mon, 6 Mar 2023 20:09:26 +0000 (UTC) Received: from llong.com (dhcp-17-153.bos.redhat.com [10.18.17.153]) by smtp.corp.redhat.com (Postfix) with ESMTP id 22F58400DFA1; Mon, 6 Mar 2023 20:09:26 +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 , Waiman Long Subject: [PATCH 1/5] cgroup/cpuset: Skip task update if hotplug doesn't affect current cpuset Date: Mon, 6 Mar 2023 15:08:45 -0500 Message-Id: <20230306200849.376804-2-longman@redhat.com> In-Reply-To: <20230306200849.376804-1-longman@redhat.com> References: <20230306200849.376804-1-longman@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org If a hotplug event doesn't affect the current cpuset, there is no point to call hotplug_update_tasks() or hotplug_update_tasks_legacy(). So just skip it. Signed-off-by: Waiman Long Reviewed-by: Michal Koutný --- kernel/cgroup/cpuset.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 636f1c682ac0..a801abad3bac 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3508,6 +3508,8 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) update_tasks: cpus_updated = !cpumask_equal(&new_cpus, cs->effective_cpus); mems_updated = !nodes_equal(new_mems, cs->effective_mems); + if (!cpus_updated && !mems_updated) + goto unlock; /* Hotplug doesn't affect this cpuset */ if (mems_updated) check_insane_mems_config(&new_mems); @@ -3519,6 +3521,7 @@ static void cpuset_hotplug_update_tasks(struct cpuset *cs, struct tmpmasks *tmp) hotplug_update_tasks_legacy(cs, &new_cpus, &new_mems, cpus_updated, mems_updated); +unlock: percpu_up_write(&cpuset_rwsem); }