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 X-Spam-Level: X-Spam-Status: No, score=-9.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B0FD8C31E40 for ; Mon, 12 Aug 2019 23:38:02 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6EBBA20679 for ; Mon, 12 Aug 2019 23:38:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="MIb4O3Hi" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6EBBA20679 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=fb.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 0C5046B0003; Mon, 12 Aug 2019 19:38:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 07A256B0005; Mon, 12 Aug 2019 19:38:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id E30CC6B0006; Mon, 12 Aug 2019 19:38:01 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0024.hostedemail.com [216.40.44.24]) by kanga.kvack.org (Postfix) with ESMTP id C41D86B0003 for ; Mon, 12 Aug 2019 19:38:01 -0400 (EDT) Received: from smtpin30.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 7072552A2 for ; Mon, 12 Aug 2019 23:38:01 +0000 (UTC) X-FDA: 75815391162.30.dad89_bcb916a33234 X-HE-Tag: dad89_bcb916a33234 X-Filterd-Recvd-Size: 4813 Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Mon, 12 Aug 2019 23:38:00 +0000 (UTC) Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.27/8.16.0.27) with SMTP id x7CNb71k012878 for ; Mon, 12 Aug 2019 16:38:00 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=facebook; bh=tVey46Cm3zNCRvto/Hdvva3sak33TFnvfc8h7R+vI7Y=; b=MIb4O3Hiizwuwf7yUFUwxnzEV0yRBP7LlCmdkJ4WjeH6zOD2N2xgbpAqrmByyq87MEgS 6VaEboh9wxtdU7GQRgWDuMjDoALxE7LMmWSRlfjzIUVf7HmEXItNYzx/LLH0sV/dD6sS S8Ab7T2UnHEnjTZbHMFPfX0QtLYwLZn4JO4= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by m0001303.ppops.net with ESMTP id 2ubbbpstum-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Mon, 12 Aug 2019 16:38:00 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::128) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Mon, 12 Aug 2019 16:37:58 -0700 Received: by devvm2643.prn2.facebook.com (Postfix, from userid 111017) id 86A9E164048AD; Mon, 12 Aug 2019 16:37:56 -0700 (PDT) Smtp-Origin-Hostprefix: devvm From: Roman Gushchin Smtp-Origin-Hostname: devvm2643.prn2.facebook.com To: Andrew Morton , CC: Michal Hocko , Johannes Weiner , , , Roman Gushchin Smtp-Origin-Cluster: prn2c23 Subject: [PATCH] mm: memcontrol: flush percpu vmevents before releasing memcg Date: Mon, 12 Aug 2019 16:37:54 -0700 Message-ID: <20190812233754.2570543-1-guro@fb.com> X-Mailer: git-send-email 2.17.1 X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2019-08-12_09:,, signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=884 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1906280000 definitions=main-1908120232 X-FB-Internal: deliver 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: Similar to vmstats, percpu caching of local vmevents leads to an accumulation of errors on non-leaf levels. This happens because some leftovers may remain in percpu caches, so that they are never propagated up by the cgroup tree and just disappear into nonexistence with on releasing of the memory cgroup. To fix this issue let's accumulate and propagate percpu vmevents values before releasing the memory cgroup similar to what we're doing with vmstats. Since on cpu hotplug we do flush percpu vmstats anyway, we can iterate only over online cpus. Fixes: 42a300353577 ("mm: memcontrol: fix recursive statistics correctness & scalabilty") Signed-off-by: Roman Gushchin Cc: Johannes Weiner --- mm/memcontrol.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 6d2427abcc0c..249187907339 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3459,6 +3459,25 @@ static void memcg_flush_percpu_vmstats(struct mem_cgroup *memcg, bool slab_only) } } +static void memcg_flush_percpu_vmevents(struct mem_cgroup *memcg) +{ + unsigned long events[NR_VM_EVENT_ITEMS]; + struct mem_cgroup *mi; + int cpu, i; + + for (i = 0; i < NR_VM_EVENT_ITEMS; i++) + events[i] = 0; + + for_each_online_cpu(cpu) + for (i = 0; i < NR_VM_EVENT_ITEMS; i++) + events[i] += raw_cpu_read( + memcg->vmstats_percpu->events[i]); + + for (mi = memcg; mi; mi = parent_mem_cgroup(mi)) + for (i = 0; i < NR_VM_EVENT_ITEMS; i++) + atomic_long_add(events[i], &mi->vmevents[i]); +} + static void memcg_offline_kmem(struct mem_cgroup *memcg) { struct cgroup_subsys_state *css; @@ -4860,10 +4879,11 @@ static void __mem_cgroup_free(struct mem_cgroup *memcg) int node; /* - * Flush percpu vmstats to guarantee the value correctness + * Flush percpu vmstats and vmevents to guarantee the value correctness * on parent's and all ancestor levels. */ memcg_flush_percpu_vmstats(memcg, false); + memcg_flush_percpu_vmevents(memcg); for_each_node(node) free_mem_cgroup_per_node_info(memcg, node); free_percpu(memcg->vmstats_percpu); -- 2.21.0