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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 948F6C433F5 for ; Mon, 25 Apr 2022 02:10:09 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id EC1016B0098; Sun, 24 Apr 2022 22:10:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E49306B0099; Sun, 24 Apr 2022 22:10:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id CC2EB6B009A; Sun, 24 Apr 2022 22:10:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.26]) by kanga.kvack.org (Postfix) with ESMTP id BA3CD6B0098 for ; Sun, 24 Apr 2022 22:10:08 -0400 (EDT) Received: from smtpin04.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 944E8270ED for ; Mon, 25 Apr 2022 02:10:08 +0000 (UTC) X-FDA: 79393771296.04.C642C41 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf18.hostedemail.com (Postfix) with ESMTP id 6E18D1C0039 for ; Mon, 25 Apr 2022 02:10:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1650852607; 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=OUIiyn3SXc0B9Nrscx1i9n88mUKK/2od6hX1NiwMSXT57W3lakndtjlklOdHftZerf86qx +A04pZDCC4Gk7oE1ksPLoH3ScvN+3SW+Az0PeE+iPUxrKlBbi+995lhx7aDQUvfrMSym1p Q82lTPQXExvc25t6zHd1B83w9PbD/ak= 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 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 6E18D1C0039 X-Stat-Signature: mfmkm39fwr6itc5ozz5rhg1sd1zsfu5m X-Rspam-User: Authentication-Results: imf18.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=OUIiyn3S; spf=none (imf18.hostedemail.com: domain of longman@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=longman@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-HE-Tag: 1650852604-711952 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: 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); -- 2.27.0