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=-9.8 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=unavailable 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 412D8CA9EA0 for ; Fri, 25 Oct 2019 23:29:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1455421872 for ; Fri, 25 Oct 2019 23:29:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="WqnNccPH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726198AbfJYX2h (ORCPT ); Fri, 25 Oct 2019 19:28:37 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:19410 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725847AbfJYX2g (ORCPT ); Fri, 25 Oct 2019 19:28:36 -0400 Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id x9PNNu5W012210 for ; Fri, 25 Oct 2019 16:28:35 -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=ZG/Rp0U9V1GZOvfP/+5tTW4GxOxccc3k62QOVqXPKFw=; b=WqnNccPHtxf/h2T43Jhgq/aMjlDc8eyeqXajd6mZqGvxeNk/wHtUIYP99KYCMc9dE7ye qlUZT7/cKlbgZnJlEj1UlCkniS7ZJXbVzHILjKw5FoQtwaBiC7+VI8DDz6rp1k36Y9vC AEHNNYpHSrtnNkfaalyYCKGwk8BhzxCpPng= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2vv7ah8w71-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 25 Oct 2019 16:28:35 -0700 Received: from 2401:db00:30:6007:face:0:1:0 (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Fri, 25 Oct 2019 16:28:34 -0700 Received: by devvm2643.prn2.facebook.com (Postfix, from userid 111017) id 89D70192BA24C; Fri, 25 Oct 2019 16:28:31 -0700 (PDT) Smtp-Origin-Hostprefix: devvm From: Roman Gushchin Smtp-Origin-Hostname: devvm2643.prn2.facebook.com To: CC: Michal Hocko , Johannes Weiner , , , Roman Gushchin , Vladimir Davydov , Shakeel Butt Smtp-Origin-Cluster: prn2c23 Subject: [PATCH] mm: slab: make page_cgroup_ino() to recognize non-compound slab pages properly Date: Fri, 25 Oct 2019 16:27:10 -0700 Message-ID: <20191025232710.4081957-1-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=2.50.10434:6.0.95,1.0.8 definitions=2019-10-25_11:2019-10-25,2019-10-25 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 lowpriorityscore=0 phishscore=0 mlxscore=0 spamscore=0 priorityscore=1501 adultscore=0 mlxlogscore=999 malwarescore=0 bulkscore=0 impostorscore=0 suspectscore=1 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1908290000 definitions=main-1910250215 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org page_cgroup_ino() doesn't return a valid memcg pointer for non-compund slab pages, because it depends on PgHead AND PgSlab flags to be set to determine the memory cgroup from the kmem_cache. It's correct for compound pages, but not for generic small pages. Those don't have PgHead set, so it ends up returning zero. Fix this by replacing the condition to PageSlab() && !PageTail(). Before this patch: [root@localhost ~]# ./page-types -c /sys/fs/cgroup/user.slice/user-0.slice/user@0.service/ | grep slab 0x0000000000000080 38 0 _______S___________________________________ slab After this patch: [root@localhost ~]# ./page-types -c /sys/fs/cgroup/user.slice/user-0.slice/user@0.service/ | grep slab 0x0000000000000080 147 0 _______S___________________________________ slab Fixes: 4d96ba353075 ("mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages") Signed-off-by: Roman Gushchin Cc: Vladimir Davydov Cc: Shakeel Butt --- mm/memcontrol.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index ea085877c548..00b4188b1bed 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -476,7 +476,7 @@ ino_t page_cgroup_ino(struct page *page) unsigned long ino = 0; rcu_read_lock(); - if (PageHead(page) && PageSlab(page)) + if (PageSlab(page) && !PageTail(page)) memcg = memcg_from_slab_page(page); else memcg = READ_ONCE(page->mem_cgroup); -- 2.17.1