From patchwork Wed Apr 27 14:54:28 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 12828927 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 A4650C433FE for ; Wed, 27 Apr 2022 14:55:00 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 1F9836B0073; Wed, 27 Apr 2022 10:55:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 1AA056B0075; Wed, 27 Apr 2022 10:55:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 070CB6B0078; Wed, 27 Apr 2022 10:55:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.28]) by kanga.kvack.org (Postfix) with ESMTP id ED9356B0073 for ; Wed, 27 Apr 2022 10:54:59 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id C1E012866C for ; Wed, 27 Apr 2022 14:54:59 +0000 (UTC) X-FDA: 79402956318.12.17C8E27 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf21.hostedemail.com (Postfix) with ESMTP id F1E991C0064 for ; Wed, 27 Apr 2022 14:54:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1651071298; 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=0IQvTcMEBnE+yly3Jqj1m7ej/vPl078aXENmc+H4j+E=; b=TEngU5GOTK+F4klnOPzHg3u2jWtKT2xNnnZzPRBay5XpnHRMka7kNKJ/+EywUdV01ECQvj x0DEMVoXI+50tH6T0D4jfetrbq59yfts4hYUZT41/82L7Y8htyy7JoFOJ5R383EkniRRnv ZZ0txrwjcycMkZCALJIfDP5TojidD0M= 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-390-Ady9gyINNF6aO5JBgqcudA-1; Wed, 27 Apr 2022 10:54:51 -0400 X-MC-Unique: Ady9gyINNF6aO5JBgqcudA-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 6E42185A5BE; Wed, 27 Apr 2022 14:54:50 +0000 (UTC) Received: from llong.com (unknown [10.22.11.205]) by smtp.corp.redhat.com (Postfix) with ESMTP id A33FD20296A5; Wed, 27 Apr 2022 14:54:41 +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, =?utf-8?q?Michal_Koutn=C3=BD?= , Waiman Long , stable@vger.kernel.org Subject: [PATCH v3] cgroup/cpuset: Remove cpus_allowed/mems_allowed setup in cpuset_init_smp() Date: Wed, 27 Apr 2022 10:54:28 -0400 Message-Id: <20220427145428.1411867-1-longman@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Stat-Signature: q8d6cwgsnxmu17hedihwbz13hp3jdfcj X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: F1E991C0064 X-Rspam-User: Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=TEngU5GO; dmarc=pass (policy=none) header.from=redhat.com; spf=none (imf21.hostedemail.com: domain of longman@redhat.com has no SPF policy when checking 170.10.133.124) smtp.mailfrom=longman@redhat.com X-HE-Tag: 1651071295-438723 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() call just sets all the bits in the masks. The second cpuset_bind() call sets cpus_allowed and mems_allowed to the default v2 values. The third cpuset_init_smp() call sets them back to v1 values. For systems with cgroup v2 setup, cpuset_bind() is called once. 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. For systems with cgroup v1 setup, cpuset_bind() is called again by rebind_subsystem() when the v1 cpuset filesystem is mounted as shown in the dmesg log below with an instrumented kernel. [ 2.609781] cpuset_bind() called - v2 = 1 [ 3.079473] cpuset_init_smp() called [ 7.103710] cpuset_bind() called - v2 = 0 smp_init() is called after the first two init functions. So we don't have a complete list of active cpus and memory nodes until later in cpuset_init_smp() which is the right time to set up effective_cpus and effective_mems. To fix this cgroup v2 mask setup problem, the potentially incorrect cpus_allowed & mems_allowed setting in cpuset_init_smp() are removed. For cgroup v2 systems, the initial cpuset_bind() call will set the masks correctly. For cgroup v1 systems, the second call to cpuset_bind() will do the right setup. cc: stable@vger.kernel.org Signed-off-by: Waiman Long Tested-by: Feng Tang Reviewed-by: Michal Koutný --- kernel/cgroup/cpuset.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 9390bfd9f1cd..71a418858a5e 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -3390,8 +3390,11 @@ 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]; + /* + * cpus_allowd/mems_allowed set to v2 values in the initial + * cpuset_bind() call will be reset to v1 values in another + * cpuset_bind() call when v1 cpuset is mounted. + */ top_cpuset.old_mems_allowed = top_cpuset.mems_allowed; cpumask_copy(top_cpuset.effective_cpus, cpu_active_mask);