From patchwork Wed Sep 30 22:49:26 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 11810451 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B31E6112C for ; Wed, 30 Sep 2020 22:50:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97EC32072E for ; Wed, 30 Sep 2020 22:50:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="Ahw38LID" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731812AbgI3WuV (ORCPT ); Wed, 30 Sep 2020 18:50:21 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:10560 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731851AbgI3WuG (ORCPT ); Wed, 30 Sep 2020 18:50:06 -0400 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 08UMo2pV028498 for ; Wed, 30 Sep 2020 15:50:04 -0700 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=6o+g6CvLKaTKQuIHDUh/KcMdLPvg7ltHmTb/OOFUgJM=; b=Ahw38LIDJpON7f8Q7HLkr09kdWe++6F61Y3UZ06ozaZZPdoan6qxAM/EyOMLhRpuneUt 7lz2IQsgIo4fNudAJqg53AfoFwAZbEki5H7/CrVoK/UBLWJqKd8uohRT9Vnxi5ldh9ko g1+B7zT3XsGCAUaN3QsCG6ASkla7sPpcGdw= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 33vtgc39kr-6 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 30 Sep 2020 15:50:04 -0700 Received: from intmgw004.08.frc2.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; Wed, 30 Sep 2020 15:49:58 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id BDA8862E586A; Wed, 30 Sep 2020 15:49:53 -0700 (PDT) From: Song Liu To: , CC: , , , , , Song Liu Subject: [PATCH v5 bpf-next 1/2] bpf: introduce BPF_F_PRESERVE_ELEMS for perf event array Date: Wed, 30 Sep 2020 15:49:26 -0700 Message-ID: <20200930224927.1936644-2-songliubraving@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200930224927.1936644-1-songliubraving@fb.com> References: <20200930224927.1936644-1-songliubraving@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-30_13:2020-09-30,2020-09-30 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 spamscore=0 bulkscore=0 lowpriorityscore=0 suspectscore=2 impostorscore=0 phishscore=0 adultscore=0 priorityscore=1501 malwarescore=0 mlxlogscore=999 mlxscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009300184 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Currently, perf event in perf event array is removed from the array when the map fd used to add the event is closed. This behavior makes it difficult to the share perf events with perf event array. Introduce perf event map that keeps the perf event open with a new flag BPF_F_PRESERVE_ELEMS. With this flag set, perf events in the array are not removed when the original map fd is closed. Instead, the perf event will stay in the map until 1) it is explicitly removed from the array; or 2) the array is freed. Signed-off-by: Song Liu --- include/uapi/linux/bpf.h | 3 +++ kernel/bpf/arraymap.c | 19 +++++++++++++++++-- tools/include/uapi/linux/bpf.h | 3 +++ 3 files changed, 23 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 1f17c6752debb..4f556cfcbfbee 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -414,6 +414,9 @@ enum { /* Enable memory-mapping BPF map */ BPF_F_MMAPABLE = (1U << 10), + +/* Share perf_event among processes */ + BPF_F_PRESERVE_ELEMS = (1U << 11), }; /* Flags for BPF_PROG_QUERY. */ diff --git a/kernel/bpf/arraymap.c b/kernel/bpf/arraymap.c index e5fd31268ae02..bd777dd6f9677 100644 --- a/kernel/bpf/arraymap.c +++ b/kernel/bpf/arraymap.c @@ -15,7 +15,8 @@ #include "map_in_map.h" #define ARRAY_CREATE_FLAG_MASK \ - (BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK) + (BPF_F_NUMA_NODE | BPF_F_MMAPABLE | BPF_F_ACCESS_MASK | \ + BPF_F_PRESERVE_ELEMS) static void bpf_array_free_percpu(struct bpf_array *array) { @@ -64,6 +65,10 @@ int array_map_alloc_check(union bpf_attr *attr) attr->map_flags & BPF_F_MMAPABLE) return -EINVAL; + if (attr->map_type != BPF_MAP_TYPE_PERF_EVENT_ARRAY && + attr->map_flags & BPF_F_PRESERVE_ELEMS) + return -EINVAL; + if (attr->value_size > KMALLOC_MAX_SIZE) /* if value_size is bigger, the user space won't be able to * access the elements. @@ -1134,6 +1139,9 @@ static void perf_event_fd_array_release(struct bpf_map *map, struct bpf_event_entry *ee; int i; + if (map->map_flags & BPF_F_PRESERVE_ELEMS) + return; + rcu_read_lock(); for (i = 0; i < array->map.max_entries; i++) { ee = READ_ONCE(array->ptrs[i]); @@ -1143,12 +1151,19 @@ static void perf_event_fd_array_release(struct bpf_map *map, rcu_read_unlock(); } +static void perf_event_fd_array_map_free(struct bpf_map *map) +{ + if (map->map_flags & BPF_F_PRESERVE_ELEMS) + bpf_fd_array_map_clear(map); + fd_array_map_free(map); +} + static int perf_event_array_map_btf_id; const struct bpf_map_ops perf_event_array_map_ops = { .map_meta_equal = bpf_map_meta_equal, .map_alloc_check = fd_array_map_alloc_check, .map_alloc = array_map_alloc, - .map_free = fd_array_map_free, + .map_free = perf_event_fd_array_map_free, .map_get_next_key = array_map_get_next_key, .map_lookup_elem = fd_array_map_lookup_elem, .map_delete_elem = fd_array_map_delete_elem, diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 1f17c6752debb..4f556cfcbfbee 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -414,6 +414,9 @@ enum { /* Enable memory-mapping BPF map */ BPF_F_MMAPABLE = (1U << 10), + +/* Share perf_event among processes */ + BPF_F_PRESERVE_ELEMS = (1U << 11), }; /* Flags for BPF_PROG_QUERY. */ From patchwork Wed Sep 30 22:49:27 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 11810453 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DEB466CA for ; Wed, 30 Sep 2020 22:50:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C51B12075F for ; Wed, 30 Sep 2020 22:50:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="qvGf3XJh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731868AbgI3WuV (ORCPT ); Wed, 30 Sep 2020 18:50:21 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:31376 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1731828AbgI3WuJ (ORCPT ); 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Wed, 30 Sep 2020 15:49:58 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id E45FD62E586A; Wed, 30 Sep 2020 15:49:56 -0700 (PDT) From: Song Liu To: , CC: , , , , , Song Liu Subject: [PATCH v5 bpf-next 2/2] selftests/bpf: add tests for BPF_F_PRESERVE_ELEMS Date: Wed, 30 Sep 2020 15:49:27 -0700 Message-ID: <20200930224927.1936644-3-songliubraving@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200930224927.1936644-1-songliubraving@fb.com> References: <20200930224927.1936644-1-songliubraving@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.235,18.0.687 definitions=2020-09-30_13:2020-09-30,2020-09-30 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 adultscore=0 spamscore=0 impostorscore=0 clxscore=1015 malwarescore=0 phishscore=0 mlxlogscore=999 mlxscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009300184 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add tests for perf event array with and without BPF_F_PRESERVE_ELEMS. Add a perf event to array via fd mfd. Without BPF_F_PRESERVE_ELEMS, the perf event is removed when mfd is closed. With BPF_F_PRESERVE_ELEMS, the perf event is removed when the map is freed. Signed-off-by: Song Liu --- .../bpf/prog_tests/pe_preserve_elems.c | 66 +++++++++++++++++++ .../bpf/progs/test_pe_preserve_elems.c | 42 ++++++++++++ 2 files changed, 108 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/pe_preserve_elems.c create mode 100644 tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c diff --git a/tools/testing/selftests/bpf/prog_tests/pe_preserve_elems.c b/tools/testing/selftests/bpf/prog_tests/pe_preserve_elems.c new file mode 100644 index 0000000000000..673d38395253b --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/pe_preserve_elems.c @@ -0,0 +1,66 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2019 Facebook */ +#include +#include +#include "test_pe_preserve_elems.skel.h" + +static int duration; + +static void test_one_map(struct bpf_map *map, struct bpf_program *prog, + bool has_share_pe) +{ + int err, key = 0, pfd = -1, mfd = bpf_map__fd(map); + DECLARE_LIBBPF_OPTS(bpf_test_run_opts, opts); + struct perf_event_attr attr = { + .size = sizeof(struct perf_event_attr), + .type = PERF_TYPE_SOFTWARE, + .config = PERF_COUNT_SW_CPU_CLOCK, + }; + + pfd = syscall(__NR_perf_event_open, &attr, 0 /* pid */, + -1 /* cpu 0 */, -1 /* group id */, 0 /* flags */); + if (CHECK(pfd < 0, "perf_event_open", "failed\n")) + return; + + err = bpf_map_update_elem(mfd, &key, &pfd, BPF_ANY); + close(pfd); + if (CHECK(err < 0, "bpf_map_update_elem", "failed\n")) + return; + + err = bpf_prog_test_run_opts(bpf_program__fd(prog), &opts); + if (CHECK(err < 0, "bpf_prog_test_run_opts", "failed\n")) + return; + if (CHECK(opts.retval != 0, "bpf_perf_event_read_value", + "failed with %d\n", opts.retval)) + return; + + /* closing mfd, prog still holds a reference on map */ + close(mfd); + + err = bpf_prog_test_run_opts(bpf_program__fd(prog), &opts); + if (CHECK(err < 0, "bpf_prog_test_run_opts", "failed\n")) + return; + + if (has_share_pe) { + CHECK(opts.retval != 0, "bpf_perf_event_read_value", + "failed with %d\n", opts.retval); + } else { + CHECK(opts.retval != -ENOENT, "bpf_perf_event_read_value", + "should have failed with %d, but got %d\n", -ENOENT, + opts.retval); + } +} + +void test_pe_preserve_elems(void) +{ + struct test_pe_preserve_elems *skel; + + skel = test_pe_preserve_elems__open_and_load(); + if (CHECK(!skel, "skel_open", "failed to open skeleton\n")) + return; + + test_one_map(skel->maps.array_1, skel->progs.read_array_1, false); + test_one_map(skel->maps.array_2, skel->progs.read_array_2, true); + + test_pe_preserve_elems__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c b/tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c new file mode 100644 index 0000000000000..726a5e4823af7 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook +#include +#include +#include + +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __uint(max_entries, 1); + __uint(key_size, sizeof(int)); + __uint(value_size, sizeof(int)); +} array_1 SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); + __uint(max_entries, 1); + __uint(key_size, sizeof(int)); + __uint(value_size, sizeof(int)); + __uint(map_flags, BPF_F_PRESERVE_ELEMS); +} array_2 SEC(".maps"); + +SEC("raw_tp/sched_switch") +int BPF_PROG(read_array_1) +{ + struct bpf_perf_event_value val; + long ret; + + ret = bpf_perf_event_read_value(&array_1, 0, &val, sizeof(val)); + return ret; +} + +SEC("raw_tp/task_rename") +int BPF_PROG(read_array_2) +{ + struct bpf_perf_event_value val; + long ret; + + ret = bpf_perf_event_read_value(&array_2, 0, &val, sizeof(val)); + return ret; +} + +char LICENSE[] SEC("license") = "GPL";