From patchwork Mon Apr 25 02:09:26 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 566006 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 E9412C433EF for ; Mon, 25 Apr 2022 02:10:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234055AbiDYCNa (ORCPT ); Sun, 24 Apr 2022 22:13:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56860 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240346AbiDYCN1 (ORCPT ); Sun, 24 Apr 2022 22:13:27 -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 ESMTP id A3C9F10E4 for ; Sun, 24 Apr 2022 19:10:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1650852608; 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; bh=IWt3Bi21zseUs/ls2Wi4USmCY2Ri5eVFWeb4jdyhkTo=; b=X5fNKqaAsmE182DHL6wtJG1+pbctajgbeQ/kRDGbFoznzE0oLAEMvmR0fddeMSD1hAlbeu 7LLlcJNqemyfEl3SMLGVhnRb3MIxt9+8yTgc49KwAClg4Scp7QZetvById45TjePwEsOZN j9oaso1YSSXxD7nAuuk95XnTjGh318U= 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-578-3p3NdwLTNfuzW-O3zKYrLw-1; Sun, 24 Apr 2022 22:10:01 -0400 X-MC-Unique: 3p3NdwLTNfuzW-O3zKYrLw-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id B8C44811E75; Mon, 25 Apr 2022 02:09:55 +0000 (UTC) Received: from llong.com (unknown [10.22.8.132]) by smtp.corp.redhat.com (Postfix) with ESMTP id EA0122026D6A; Mon, 25 Apr 2022 02:09:50 +0000 (UTC) From: Waiman Long To: Tejun Heo , Zefan Li , Johannes Weiner Cc: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Feng Tang , Andrew Morton , Michal Hocko , Dave Hansen , ying.huang@intel.com, Waiman Long , stable@vger.kernel.org Subject: [PATCH] cgroup/cpuset: Remove redundant cpu/node masks setup in cpuset_init_smp() Date: Sun, 24 Apr 2022 22:09:26 -0400 Message-Id: <20220425020926.1264611-1-longman@redhat.com> MIME-Version: 1.0 Content-type: text/plain X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org There are 3 places where the cpu and node masks of the top cpuset can be initialized in the order they are executed: 1) start_kernel -> cpuset_init() 2) start_kernel -> cgroup_init() -> cpuset_bind() 3) kernel_init_freeable() -> do_basic_setup() -> cpuset_init_smp() The first cpuset_init() function just sets all the bits in the masks. The last one executed is cpuset_init_smp() which sets up cpu and node masks suitable for v1, but not v2. cpuset_bind() does the right setup for both v1 and v2 assuming that effective_mems and effective_cpus have been set up properly which is not strictly the case here. As a result, cpu and memory node hot add may fail to update the cpu and node masks of the top cpuset to include the newly added cpu or node in a cgroup v2 environment. To fix this problem, the redundant cpus_allowed and mems_allowed mask setup in cpuset_init_smp() are removed. The effective_cpus and effective_mems setup there are moved to cpuset_bind(). cc: stable@vger.kernel.org Signed-off-by: Waiman Long --- kernel/cgroup/cpuset.c | 10 +++------- 1 file changed, 3 insertions(+), 7 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 9390bfd9f1cd..a2e15a43397e 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -2961,6 +2961,9 @@ static void cpuset_bind(struct cgroup_subsys_state *root_css) percpu_down_write(&cpuset_rwsem); spin_lock_irq(&callback_lock); + cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask); + top_cpuset.effective_mems = node_states[N_MEMORY]; + if (is_in_v2_mode()) { cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask); top_cpuset.mems_allowed = node_possible_map; @@ -3390,13 +3393,6 @@ static struct notifier_block cpuset_track_online_nodes_nb = { */ void __init cpuset_init_smp(void) { - cpumask_copy(top_cpuset.cpus_allowed, cpu_active_mask); - top_cpuset.mems_allowed = node_states[N_MEMORY]; - top_cpuset.old_mems_allowed = top_cpuset.mems_allowed; - - cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask); - top_cpuset.effective_mems = node_states[N_MEMORY]; - register_hotmemory_notifier(&cpuset_track_online_nodes_nb); cpuset_migrate_mm_wq = alloc_ordered_workqueue("cpuset_migrate_mm", 0);