From patchwork Tue Sep 29 21:56:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 11807247 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 4106C13B2 for ; Tue, 29 Sep 2020 21:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 250BF2083B for ; Tue, 29 Sep 2020 21:57:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="F+SAq2kb" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728530AbgI2V5P (ORCPT ); Tue, 29 Sep 2020 17:57:15 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:35428 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728041AbgI2V5M (ORCPT ); Tue, 29 Sep 2020 17:57:12 -0400 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 08TLucqo014970 for ; Tue, 29 Sep 2020 14:57:11 -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=0p/MpUuBPlM9q5zBlXyWceVaFyhw798LlXRz7q5M2vE=; b=F+SAq2kbD2TSXm11dAtsDnI+u8hHq0yF0OFfifYX0tr5IUFnBVUqYjLOgHy7lw9pEkbz BPSx1YRqDSWjRlUW0RLP2gedWvtCiXvZwt16RlRST8sx8HOXlP8OgtgXVbEA0axJj5VV JINoEc7oXhdC6QcOFwixmaAkkNBUS1kPBQA= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 33v3vtu8tn-11 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 29 Sep 2020 14:57:11 -0700 Received: from intmgw002.08.frc2.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::e) 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 14:57:05 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id 6F3F062E55BF; Tue, 29 Sep 2020 14:57:04 -0700 (PDT) From: Song Liu To: , CC: , , , , , Song Liu Subject: [PATCH v2 bpf-next 1/2] bpf: introduce BPF_F_PRESERVE_ELEMS for perf event array Date: Tue, 29 Sep 2020 14:56:58 -0700 Message-ID: <20200929215659.3938706-2-songliubraving@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200929215659.3938706-1-songliubraving@fb.com> References: <20200929215659.3938706-1-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=2020-09-29_14:2020-09-29,2020-09-29 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 lowpriorityscore=0 suspectscore=2 phishscore=0 mlxlogscore=999 clxscore=1015 bulkscore=0 impostorscore=0 adultscore=0 priorityscore=1501 spamscore=0 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009290188 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 | 21 +++++++++++++++++++-- tools/include/uapi/linux/bpf.h | 3 +++ 3 files changed, 25 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 82522f05c0213..ea78eb89f8d67 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..644ceb67350a6 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. @@ -778,6 +783,15 @@ static int fd_array_map_delete_elem(struct bpf_map *map, void *key) } } +static void bpf_fd_array_map_clear(struct bpf_map *map); + +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 void *prog_fd_array_get_ptr(struct bpf_map *map, struct file *map_file, int fd) { @@ -1134,6 +1148,9 @@ 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]); @@ -1148,7 +1165,7 @@ 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 82522f05c0213..ea78eb89f8d67 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 Tue Sep 29 21:56:59 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 11807245 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 1C757139F for ; Tue, 29 Sep 2020 21:57:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE9D12083B for ; Tue, 29 Sep 2020 21:57:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="jFfT9UkE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728192AbgI2V5P (ORCPT ); Tue, 29 Sep 2020 17:57:15 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:33082 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728357AbgI2V5N (ORCPT ); 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Tue, 29 Sep 2020 14:57:12 -0700 Received: by devbig006.ftw2.facebook.com (Postfix, from userid 4523) id A63AC62E55BF; Tue, 29 Sep 2020 14:57:07 -0700 (PDT) From: Song Liu To: , CC: , , , , , Song Liu Subject: [PATCH v2 bpf-next 2/2] selftests/bpf: add tests for BPF_F_PRESERVE_ELEMS Date: Tue, 29 Sep 2020 14:56:59 -0700 Message-ID: <20200929215659.3938706-3-songliubraving@fb.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20200929215659.3938706-1-songliubraving@fb.com> References: <20200929215659.3938706-1-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=2020-09-29_14:2020-09-29,2020-09-29 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 adultscore=0 bulkscore=0 priorityscore=1501 impostorscore=0 phishscore=0 malwarescore=0 suspectscore=0 lowpriorityscore=0 mlxlogscore=999 spamscore=0 clxscore=1015 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2006250000 definitions=main-2009290188 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 | 44 +++++++++++++ 2 files changed, 110 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..dc77e406de41f --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_pe_preserve_elems.c @@ -0,0 +1,44 @@ +// SPDX-License-Identifier: GPL-2.0 +// Copyright (c) 2020 Facebook +#include "vmlinux.h" +#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)); + bpf_printk("read_array_1 returns %ld", ret); + 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)); + bpf_printk("read_array_2 returns %ld", ret); + return ret; +} + +char LICENSE[] SEC("license") = "GPL";