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=-7.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no 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 2C6CFC47420 for ; Tue, 29 Sep 2020 23:59:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C5EA321531 for ; Tue, 29 Sep 2020 23:59:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="IO8EcTYI" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729292AbgI2X7f (ORCPT ); Tue, 29 Sep 2020 19:59:35 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:6238 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728851AbgI2X7f (ORCPT ); Tue, 29 Sep 2020 19:59:35 -0400 Received: from pps.filterd (m0109331.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08TNsHVA011766 for ; Tue, 29 Sep 2020 16:59:34 -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-transfer-encoding : content-type; s=facebook; bh=T1Yi2eDG1rI7nmoPC5+4fj7KjlElmvHPWj+SaKolS0M=; b=IO8EcTYIa6ISyY3BUCiZLxmw+dPwl1Hmp4mWglXu5YkDLh/Fz08dV4VQ6ae8uSus1SQy UYut7Di8x6Bj/6laBPIC2mGstCJD+7QAgnm7tyKW1j65ln0xyZAcQ2lToNN7a87dXuwo CwRLcfQYOk4ZOAJfA8Gkx4ZRQ1Vc0fxHQ3U= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 33t3fhg73s-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 29 Sep 2020 16:59:34 -0700 Received: from intmgw001.41.prn1.facebook.com (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 15.1.1979.3; Tue, 29 Sep 2020 16:59:33 -0700 Received: by devvm1755.vll0.facebook.com (Postfix, from userid 111017) id 63789D62150; Tue, 29 Sep 2020 16:59:21 -0700 (PDT) From: Roman Gushchin To: Andrew Morton CC: Shakeel Butt , Johannes Weiner , Michal Hocko , , , , Roman Gushchin Subject: [PATCH v3 0/4] mm: allow mapping accounted kernel pages to userspace Date: Tue, 29 Sep 2020 16:59:16 -0700 Message-ID: <20200929235920.537849-1-guro@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-FB-Internal: Safe Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-29_14:2020-09-29,2020-09-29 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 impostorscore=0 spamscore=0 mlxscore=0 malwarescore=0 bulkscore=0 lowpriorityscore=0 phishscore=0 adultscore=0 clxscore=1015 priorityscore=1501 mlxlogscore=545 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009290203 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently a non-slab kernel page which has been charged to a memory cgroup can't be mapped to userspace. The underlying reason is simple: PageKmemcg flag is defined as a page type (like buddy, offline, etc), so it takes a bit from a page->mapped counter. Pages with a type set can't be mapped to userspace. But in general the kmemcg flag has nothing to do with mapping to userspace. It only means that the page has been accounted by the page allocator, so it has to be properly uncharged on release. Some bpf maps are mapping the vmalloc-based memory to userspace, and their memory can't be accounted because of this implementation detail. This patchset removes this limitation by moving the PageKmemcg flag into one of the free bits of the page->mem_cgroup pointer. Also it formalizes all accesses to the page->mem_cgroup and page->obj_cgroups using new helpers, adds several checks and removes a couple of obsolete functions. As the result the code became more robust with fewer open-coded bits tricks. v3: - READ_ONCE() in page_memcg_rcu() and page_objcgs*(), by Johannes - many cosmetic changes and renamings, by Johannes v2: - fixed a bug in page_obj_cgroups_check() - moved some definitions between patches, by Shakeel - dropped the memcg flags mutual exclusion requirement, by Shakeel v1: - added and fixed comments, by Shakeel - added some VM_BUG_ON() checks - fixed the debug output format of page->memcg_data Roman Gushchin (4): mm: memcontrol: use helpers to access page's memcg data mm: memcontrol/slab: use helpers to access slab page's memcg_data mm: introduce page memcg flags mm: convert page kmemcg type to a page memcg flag fs/buffer.c | 2 +- fs/iomap/buffered-io.c | 2 +- include/linux/memcontrol.h | 294 ++++++++++++++++++++++++++++++- include/linux/mm.h | 22 --- include/linux/mm_types.h | 5 +- include/linux/page-flags.h | 11 +- include/trace/events/writeback.h | 2 +- kernel/fork.c | 7 +- mm/debug.c | 4 +- mm/huge_memory.c | 4 +- mm/memcontrol.c | 139 +++++++-------- mm/page_alloc.c | 6 +- mm/page_io.c | 6 +- mm/slab.h | 38 +--- mm/workingset.c | 2 +- 15 files changed, 378 insertions(+), 166 deletions(-) --=20 2.26.2