From patchwork Thu Nov 12 22:15:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Roman Gushchin X-Patchwork-Id: 1399422 Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.a=rsa-sha256 header.s=facebook header.b=Xg9txzjW; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by ozlabs.org (Postfix) with ESMTP id 4CXGRf6ngqz9sTK for ; Fri, 13 Nov 2020 09:26:54 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727753AbgKLW0x (ORCPT ); Thu, 12 Nov 2020 17:26:53 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:45334 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727558AbgKLW0c (ORCPT ); Thu, 12 Nov 2020 17:26:32 -0500 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 0ACMLecE004636 for ; Thu, 12 Nov 2020 14:26:31 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=skuK0y/JgivfIPXNGjDE5r55wonSPjPszk7Vg56V2FQ=; b=Xg9txzjWqh96x7ffHXFIGHjOCYTHRcn0lBzORtAJcMTa7eIZZt+lpwuEiY0jsz5pFcnt mNWE4wcvwrj7wKmBwlIarHvuBdNNC63fA51kimFp4A7/+ysoVYW8JW5jc1V/Wf7MVOeD 9QFqPlXFC03tIRKbw0jCLyNETs1ceaylbD8= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 34r2n9nsps-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 12 Nov 2020 14:26:31 -0800 Received: from intmgw002.06.prn3.facebook.com (2620:10d:c085:108::8) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1979.3; Thu, 12 Nov 2020 14:26:30 -0800 Received: by devvm3388.prn0.facebook.com (Postfix, from userid 111017) id D7D7FA7D1DC; Thu, 12 Nov 2020 14:16:00 -0800 (PST) From: Roman Gushchin To: CC: Alexei Starovoitov , Daniel Borkmann , , Andrii Nakryiko , Shakeel Butt , , , , Roman Gushchin Subject: [PATCH bpf-next v5 06/34] bpf: prepare for memcg-based memory accounting for bpf maps Date: Thu, 12 Nov 2020 14:15:15 -0800 Message-ID: <20201112221543.3621014-7-guro@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201112221543.3621014-1-guro@fb.com> References: <20201112221543.3621014-1-guro@fb.com> 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=2020-11-12_14:2020-11-12,2020-11-12 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 lowpriorityscore=0 clxscore=1015 mlxscore=0 bulkscore=0 spamscore=0 mlxlogscore=999 suspectscore=38 adultscore=0 priorityscore=1501 impostorscore=0 phishscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2011120127 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In the absolute majority of cases if a process is making a kernel allocation, it's memory cgroup is getting charged. Bpf maps can be updated from an interrupt context and in such case there is no process which can be charged. It makes the memory accounting of bpf maps non-trivial. Fortunately, after commits 4127c6504f25 ("mm: kmem: enable kernel memcg accounting from interrupt contexts") and b87d8cefe43c ("mm, memcg: rework remote charging API to support nesting") it's finally possible. To do it, a pointer to the memory cgroup of the process which created the map is saved, and this cgroup is getting charged for all allocations made from an interrupt context. Allocations made from a process context will be accounted in a usual way. Signed-off-by: Roman Gushchin Acked-by: Song Liu --- include/linux/bpf.h | 4 ++++ kernel/bpf/helpers.c | 37 ++++++++++++++++++++++++++++++++++++- kernel/bpf/syscall.c | 25 +++++++++++++++++++++++++ 3 files changed, 65 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 581b2a2e78eb..1d6e7b125877 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -37,6 +37,7 @@ struct bpf_iter_aux_info; struct bpf_local_storage; struct bpf_local_storage_map; struct kobject; +struct mem_cgroup; extern struct idr btf_idr; extern spinlock_t btf_idr_lock; @@ -161,6 +162,9 @@ struct bpf_map { u32 btf_value_type_id; struct btf *btf; struct bpf_map_memory memory; +#ifdef CONFIG_MEMCG_KMEM + struct mem_cgroup *memcg; +#endif char name[BPF_OBJ_NAME_LEN]; u32 btf_vmlinux_value_type_id; bool bypass_spec_v1; diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index 25520f5eeaf6..b6327cbe7e41 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "../../lib/kstrtox.h" @@ -41,11 +42,45 @@ const struct bpf_func_proto bpf_map_lookup_elem_proto = { .arg2_type = ARG_PTR_TO_MAP_KEY, }; +#ifdef CONFIG_MEMCG_KMEM +static __always_inline int __bpf_map_update_elem(struct bpf_map *map, void *key, + void *value, u64 flags) +{ + struct mem_cgroup *old_memcg; + bool in_interrupt; + int ret; + + /* + * If update from an interrupt context results in a memory allocation, + * the memory cgroup to charge can't be determined from the context + * of the current task. Instead, we charge the memory cgroup, which + * contained a process created the map. + */ + in_interrupt = in_interrupt(); + if (in_interrupt) + old_memcg = set_active_memcg(map->memcg); + + ret = map->ops->map_update_elem(map, key, value, flags); + + if (in_interrupt) + set_active_memcg(old_memcg); + + return ret; +} +#else +static __always_inline int __bpf_map_update_elem(struct bpf_map *map, void *key, + void *value, u64 flags) +{ + return map->ops->map_update_elem(map, key, value, flags); +} +#endif + BPF_CALL_4(bpf_map_update_elem, struct bpf_map *, map, void *, key, void *, value, u64, flags) { WARN_ON_ONCE(!rcu_read_lock_held()); - return map->ops->map_update_elem(map, key, value, flags); + + return __bpf_map_update_elem(map, key, value, flags); } const struct bpf_func_proto bpf_map_update_elem_proto = { diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index f3fe9f53f93c..2d77fc2496da 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -31,6 +31,7 @@ #include #include #include +#include #define IS_FD_ARRAY(map) ((map)->map_type == BPF_MAP_TYPE_PERF_EVENT_ARRAY || \ (map)->map_type == BPF_MAP_TYPE_CGROUP_ARRAY || \ @@ -456,6 +457,27 @@ void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock) __release(&map_idr_lock); } +#ifdef CONFIG_MEMCG_KMEM +static void bpf_map_save_memcg(struct bpf_map *map) +{ + map->memcg = get_mem_cgroup_from_mm(current->mm); +} + +static void bpf_map_release_memcg(struct bpf_map *map) +{ + mem_cgroup_put(map->memcg); +} + +#else +static void bpf_map_save_memcg(struct bpf_map *map) +{ +} + +static void bpf_map_release_memcg(struct bpf_map *map) +{ +} +#endif + /* called from workqueue */ static void bpf_map_free_deferred(struct work_struct *work) { @@ -464,6 +486,7 @@ static void bpf_map_free_deferred(struct work_struct *work) bpf_map_charge_move(&mem, &map->memory); security_bpf_map_free(map); + bpf_map_release_memcg(map); /* implementation dependent freeing */ map->ops->map_free(map); bpf_map_charge_finish(&mem); @@ -875,6 +898,8 @@ static int map_create(union bpf_attr *attr) if (err) goto free_map_sec; + bpf_map_save_memcg(map); + err = bpf_map_new_fd(map, f_flags); if (err < 0) { /* failed to allocate fd.