From patchwork Wed Nov 25 03:00:45 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Gushchin X-Patchwork-Id: 11930167 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=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 D47E6C64E75 for ; Wed, 25 Nov 2020 03:04:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9E60B20872 for ; Wed, 25 Nov 2020 03:04:42 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="dKIZQ+6V" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727309AbgKYDB2 (ORCPT ); Tue, 24 Nov 2020 22:01:28 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:2666 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725776AbgKYDB1 (ORCPT ); Tue, 24 Nov 2020 22:01:27 -0500 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 0AP2sxBi004061 for ; Tue, 24 Nov 2020 19:01:24 -0800 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=8AAxYUH0WyGJT1ndbOM3xaBBwsn7b3gRx9M2lTcjzNk=; b=dKIZQ+6VqsaC0Yw25h5haNhkH9PRgl79Lyr0OzGB5bmvO2k1WLNhEZS1B+//0q0VrJNa d+fLAFF05i8Zuiuk5cffSVPhg6+MbmvA8ToRNuxekhe4IVh15qfX/pqyTwILVV0tmkFD 1O/Jq5CWogbQJ/yITZ8DXzw+gLClJg/cQ1w= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 3516xbsv6h-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 24 Nov 2020 19:01:24 -0800 Received: from intmgw002.41.prn1.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Tue, 24 Nov 2020 19:01:23 -0800 Received: by devvm3388.prn0.facebook.com (Postfix, from userid 111017) id D872016A1881; Tue, 24 Nov 2020 19:01:21 -0800 (PST) From: Roman Gushchin To: CC: , , , , , , , Subject: [PATCH bpf-next v8 00/34] bpf: switch to memcg-based memory accounting Date: Tue, 24 Nov 2020 19:00:45 -0800 Message-ID: <20201125030119.2864302-1-guro@fb.com> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-11-24_11:2020-11-24,2020-11-24 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxlogscore=999 clxscore=1015 bulkscore=0 spamscore=0 suspectscore=38 impostorscore=0 phishscore=0 malwarescore=0 adultscore=0 priorityscore=1501 mlxscore=0 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011250018 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Currently bpf is using the memlock rlimit for the memory accounting. This approach has its downsides and over time has created a significant amount of problems: 1) The limit is per-user, but because most bpf operations are performed as root, the limit has a little value. 2) It's hard to come up with a specific maximum value. Especially because the counter is shared with non-bpf use cases (e.g. memlock()). Any specific value is either too low and creates false failures or is too high and useless. 3) Charging is not connected to the actual memory allocation. Bpf code should manually calculate the estimated cost and charge the counter, and then take care of uncharging, including all fail paths. It adds to the code complexity and makes it easy to leak a charge. 4) There is no simple way of getting the current value of the counter. We've used drgn for it, but it's far from being convenient. 5) Cryptic -EPERM is returned on exceeding the limit. Libbpf even had a function to "explain" this case for users. 6) rlimits are generally considered as (at least partially) obsolete. They do not provide a comprehensive system for the control of physical resources: memory, cpu, io etc. All resource control developments in the recent years were related to cgroups. In order to overcome these problems let's switch to the memory cgroup-based memory accounting of bpf objects. With the recent addition of the percpu memory accounting, now it's possible to provide a comprehensive accounting of the memory used by bpf programs and maps. This approach has the following advantages: 1) The limit is per-cgroup and hierarchical. It's way more flexible and allows a better control over memory usage by different workloads. 2) The actual memory consumption is taken into account. It happens automatically on the allocation time if __GFP_ACCOUNT flags is passed. Uncharging is also performed automatically on releasing the memory. So the code on the bpf side becomes simpler and safer. 3) There is a simple way to get the current value and statistics. Cgroup-based accounting adds new requirements: 1) The kernel config should have CONFIG_CGROUPS and CONFIG_MEMCG_KMEM enabled. These options are usually enabled, maybe excluding tiny builds for embedded devices. 2) The system should have a configured cgroup hierarchy, including reasonable memory limits and/or guarantees. Modern systems usually delegate this task to systemd or similar task managers. Without meeting these requirements there are no limits on how much memory bpf can use and a non-root user is able to hurt the system by allocating too much. But because per-user rlimits do not provide a functional system to protect and manage physical resources anyway, anyone who seriously depends on it, should use cgroups. In general, if a process performs a bpf operation (e.g. creates or updates a map), it's memory cgroup is charged. However map updates performed from an interrupt context are charged to the memory cgroup which contained the process, which created the map. The patchset consists of the following parts: 1) 4 mm patches are required on the mm side, otherwise vmallocs cannot be mapped to userspace 2) memcg-based accounting for various bpf objects: progs and maps 3) removal of the rlimit-based accounting 4) removal of rlimit adjustments in userspace samples v8: - extended the cover letter to be more clear on new requirements, by Daniel - an approximate value is provided by map memlock info, by Alexei v7: - introduced bpf_map_kmalloc_node() and bpf_map_alloc_percpu(), by Alexei - switched allocations made from an interrupt context to new helpers, by Daniel - rebase and minor fixes v6: - rebased to the latest version of the remote charging API - fixed signatures, added acks v5: - rebased to the latest version of the remote charging API - implemented kmem accounting from an interrupt context, by Shakeel - rebased to latest changes in mm allowed to map vmallocs to userspace - fixed a build issue in kselftests, by Alexei - fixed a use-after-free bug in bpf_map_free_deferred() - added bpf line info coverage, by Shakeel - split bpf map charging preparations into a separate patch v4: - covered allocations made from an interrupt context, by Daniel - added some clarifications to the cover letter v3: - droped the userspace part for further discussions/refinements, by Andrii and Song v2: - fixed build issue, caused by the remaining rlimit-based accounting for sockhash maps Roman Gushchin (34): mm: memcontrol: use helpers to read 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 bpf: memcg-based memory accounting for bpf progs bpf: prepare for memcg-based memory accounting for bpf maps bpf: memcg-based memory accounting for bpf maps bpf: refine memcg-based memory accounting for arraymap maps bpf: refine memcg-based memory accounting for cpumap maps bpf: memcg-based memory accounting for cgroup storage maps bpf: refine memcg-based memory accounting for devmap maps bpf: refine memcg-based memory accounting for hashtab maps bpf: memcg-based memory accounting for lpm_trie maps bpf: memcg-based memory accounting for bpf ringbuffer bpf: memcg-based memory accounting for bpf local storage maps bpf: refine memcg-based memory accounting for sockmap and sockhash maps bpf: refine memcg-based memory accounting for xskmap maps bpf: eliminate rlimit-based memory accounting for arraymap maps bpf: eliminate rlimit-based memory accounting for bpf_struct_ops maps bpf: eliminate rlimit-based memory accounting for cpumap maps bpf: eliminate rlimit-based memory accounting for cgroup storage maps bpf: eliminate rlimit-based memory accounting for devmap maps bpf: eliminate rlimit-based memory accounting for hashtab maps bpf: eliminate rlimit-based memory accounting for lpm_trie maps bpf: eliminate rlimit-based memory accounting for queue_stack_maps maps bpf: eliminate rlimit-based memory accounting for reuseport_array maps bpf: eliminate rlimit-based memory accounting for bpf ringbuffer bpf: eliminate rlimit-based memory accounting for sockmap and sockhash maps bpf: eliminate rlimit-based memory accounting for stackmap maps bpf: eliminate rlimit-based memory accounting for xskmap maps bpf: eliminate rlimit-based memory accounting for bpf local storage maps bpf: eliminate rlimit-based memory accounting infra for bpf maps bpf: eliminate rlimit-based memory accounting for bpf progs bpf: samples: do not touch RLIMIT_MEMLOCK fs/buffer.c | 2 +- fs/iomap/buffered-io.c | 2 +- include/linux/bpf.h | 49 ++-- include/linux/memcontrol.h | 215 +++++++++++++++- include/linux/mm.h | 22 -- include/linux/mm_types.h | 5 +- include/linux/page-flags.h | 11 +- include/trace/events/writeback.h | 2 +- kernel/bpf/arraymap.c | 30 +-- kernel/bpf/bpf_local_storage.c | 23 +- kernel/bpf/bpf_struct_ops.c | 19 +- kernel/bpf/core.c | 22 +- kernel/bpf/cpumap.c | 39 +-- kernel/bpf/devmap.c | 25 +- kernel/bpf/hashtab.c | 34 +-- kernel/bpf/local_storage.c | 43 +--- kernel/bpf/lpm_trie.c | 20 +- kernel/bpf/queue_stack_maps.c | 16 +- kernel/bpf/reuseport_array.c | 12 +- kernel/bpf/ringbuf.c | 33 +-- kernel/bpf/stackmap.c | 16 +- kernel/bpf/syscall.c | 241 ++++++++---------- kernel/fork.c | 7 +- mm/debug.c | 4 +- mm/huge_memory.c | 4 +- mm/memcontrol.c | 139 +++++----- mm/page_alloc.c | 8 +- mm/page_io.c | 6 +- mm/slab.h | 38 +-- mm/workingset.c | 2 +- net/core/sock_map.c | 42 +-- net/xdp/xskmap.c | 16 +- samples/bpf/map_perf_test_user.c | 6 - samples/bpf/offwaketime_user.c | 6 - samples/bpf/sockex2_user.c | 2 - samples/bpf/sockex3_user.c | 2 - samples/bpf/spintest_user.c | 6 - samples/bpf/syscall_tp_user.c | 2 - samples/bpf/task_fd_query_user.c | 5 - samples/bpf/test_lru_dist.c | 3 - samples/bpf/test_map_in_map_user.c | 6 - samples/bpf/test_overhead_user.c | 2 - samples/bpf/trace_event_user.c | 2 - samples/bpf/tracex2_user.c | 6 - samples/bpf/tracex3_user.c | 6 - samples/bpf/tracex4_user.c | 6 - samples/bpf/tracex5_user.c | 3 - samples/bpf/tracex6_user.c | 3 - samples/bpf/xdp1_user.c | 6 - samples/bpf/xdp_adjust_tail_user.c | 6 - samples/bpf/xdp_monitor_user.c | 5 - samples/bpf/xdp_redirect_cpu_user.c | 6 - samples/bpf/xdp_redirect_map_user.c | 6 - samples/bpf/xdp_redirect_user.c | 6 - samples/bpf/xdp_router_ipv4_user.c | 6 - samples/bpf/xdp_rxq_info_user.c | 6 - samples/bpf/xdp_sample_pkts_user.c | 6 - samples/bpf/xdp_tx_iptunnel_user.c | 6 - samples/bpf/xdpsock_user.c | 7 - .../selftests/bpf/progs/bpf_iter_bpf_map.c | 2 +- .../selftests/bpf/progs/map_ptr_kern.c | 7 - 61 files changed, 532 insertions(+), 756 deletions(-)