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 EE55CC6FD1D for ; Fri, 17 Mar 2023 15:16:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231750AbjCQPQx (ORCPT ); Fri, 17 Mar 2023 11:16:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231389AbjCQPQm (ORCPT ); Fri, 17 Mar 2023 11:16:42 -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 AE51F3B225 for ; Fri, 17 Mar 2023 08:15:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1679066134; 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=amVdrpHTvDqA9NrS62Whbl25Xahg4lsNNZAsfD0/8D0=; b=ioUAV2tSqiYeh4qr1dxmZQ8lwrnp96Vw0tbBzUM2DxD3XEe3zRPS81r71g5bianHDKdQiB Ihxy3jszeuMYGr2vY6otjYaqAEyKDHbk6FC2EuRAblDbODC3mH89be3z2Px2pewPK6Tcd6 Kjz7BN7BOJ13qChFAoHGE0BXfzHlsq4= 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-20-dusQyZqEPyawIzgUhzWxMA-1; Fri, 17 Mar 2023 11:15:31 -0400 X-MC-Unique: dusQyZqEPyawIzgUhzWxMA-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 864BC3801EC6; Fri, 17 Mar 2023 15:15:30 +0000 (UTC) Received: from llong.com (unknown [10.22.10.238]) by smtp.corp.redhat.com (Postfix) with ESMTP id 12253492B00; 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=20Koutn=C3=BD?= , Juri Lelli , Waiman Long Subject: [PATCH v2 2/4] cgroup/cpuset: Skip task update if hotplug doesn't affect current cpuset Date: Fri, 17 Mar 2023 11:15:06 -0400 Message-Id: <20230317151508.1225282-3-longman@redhat.com> In-Reply-To: <20230317151508.1225282-1-longman@redhat.com> References: <20230317151508.1225282-1-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 f310915d1257..5b8d763555b0 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3516,6 +3516,8 @@ 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); @@ -3527,6 +3529,7 @@ 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); } -- 2.31.1