From patchwork Sun Aug 27 15:28:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 13367300 X-Patchwork-Delegate: bpf@iogearbox.net Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5CB587EE for ; Sun, 27 Aug 2023 15:28:20 +0000 (UTC) Received: from 66-220-155-178.mail-mxout.facebook.com (66-220-155-178.mail-mxout.facebook.com [66.220.155.178]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6504EEC for ; Sun, 27 Aug 2023 08:28:18 -0700 (PDT) Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id 84C02257ECFD9; Sun, 27 Aug 2023 08:28:11 -0700 (PDT) From: Yonghong Song To: bpf@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , kernel-team@fb.com, Martin KaFai Lau Subject: [PATCH bpf-next v3 08/13] selftests/bpf: Add tests for array map with local percpu kptr Date: Sun, 27 Aug 2023 08:28:11 -0700 Message-Id: <20230827152811.2000125-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230827152729.1995219-1-yonghong.song@linux.dev> References: <20230827152729.1995219-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-0.3 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_BLOCKED,RDNS_DYNAMIC,SPF_HELO_PASS,SPF_SOFTFAIL, TVD_RCVD_IP autolearn=no autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: bpf@iogearbox.net Add non-sleepable and sleepable tests with percpu kptr. For non-sleepable test, four programs are executed in the order of: 1. allocate percpu data. 2. assign values to percpu data. 3. retrieve percpu data. 4. de-allocate percpu data. The sleepable prog tried to exercise all above 4 steps in a single prog. Also for sleepable prog, rcu_read_lock is needed to protect direct percpu ptr access (from map value) and following bpf_this_cpu_ptr() and bpf_per_cpu_ptr() helpers. Signed-off-by: Yonghong Song --- .../selftests/bpf/prog_tests/percpu_alloc.c | 78 ++++++++ .../selftests/bpf/progs/percpu_alloc_array.c | 187 ++++++++++++++++++ 2 files changed, 265 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/percpu_alloc.c create mode 100644 tools/testing/selftests/bpf/progs/percpu_alloc_array.c diff --git a/tools/testing/selftests/bpf/prog_tests/percpu_alloc.c b/tools/testing/selftests/bpf/prog_tests/percpu_alloc.c new file mode 100644 index 000000000000..0fb536822f14 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/percpu_alloc.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include "percpu_alloc_array.skel.h" + +static void test_array(void) +{ + struct percpu_alloc_array *skel; + int err, prog_fd; + LIBBPF_OPTS(bpf_test_run_opts, topts); + + skel = percpu_alloc_array__open(); + if (!ASSERT_OK_PTR(skel, "percpu_alloc_array__open")) + return; + + bpf_program__set_autoload(skel->progs.test_array_map_1, true); + bpf_program__set_autoload(skel->progs.test_array_map_2, true); + bpf_program__set_autoload(skel->progs.test_array_map_3, true); + bpf_program__set_autoload(skel->progs.test_array_map_4, true); + + skel->rodata->nr_cpus = libbpf_num_possible_cpus(); + + err = percpu_alloc_array__load(skel); + if (!ASSERT_OK(err, "percpu_alloc_array__load")) + goto out; + + err = percpu_alloc_array__attach(skel); + if (!ASSERT_OK(err, "percpu_alloc_array__attach")) + goto out; + + prog_fd = bpf_program__fd(skel->progs.test_array_map_1); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run array_map 1-4"); + ASSERT_EQ(topts.retval, 0, "test_run array_map 1-4"); + ASSERT_EQ(skel->bss->cpu0_field_d, 2, "cpu0_field_d"); + ASSERT_EQ(skel->bss->sum_field_c, 1, "sum_field_c"); +out: + percpu_alloc_array__destroy(skel); +} + +static void test_array_sleepable(void) +{ + struct percpu_alloc_array *skel; + int err, prog_fd; + LIBBPF_OPTS(bpf_test_run_opts, topts); + + skel = percpu_alloc_array__open(); + if (!ASSERT_OK_PTR(skel, "percpu_alloc__open")) + return; + + bpf_program__set_autoload(skel->progs.test_array_map_10, true); + + skel->rodata->nr_cpus = libbpf_num_possible_cpus(); + + err = percpu_alloc_array__load(skel); + if (!ASSERT_OK(err, "percpu_alloc_array__load")) + goto out; + + err = percpu_alloc_array__attach(skel); + if (!ASSERT_OK(err, "percpu_alloc_array__attach")) + goto out; + + prog_fd = bpf_program__fd(skel->progs.test_array_map_10); + err = bpf_prog_test_run_opts(prog_fd, &topts); + ASSERT_OK(err, "test_run array_map_10"); + ASSERT_EQ(topts.retval, 0, "test_run array_map_10"); + ASSERT_EQ(skel->bss->cpu0_field_d, 2, "cpu0_field_d"); + ASSERT_EQ(skel->bss->sum_field_c, 1, "sum_field_c"); +out: + percpu_alloc_array__destroy(skel); +} + +void test_percpu_alloc(void) +{ + if (test__start_subtest("array")) + test_array(); + if (test__start_subtest("array_sleepable")) + test_array_sleepable(); +} diff --git a/tools/testing/selftests/bpf/progs/percpu_alloc_array.c b/tools/testing/selftests/bpf/progs/percpu_alloc_array.c new file mode 100644 index 000000000000..3bd7d47870a9 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/percpu_alloc_array.c @@ -0,0 +1,187 @@ +#include "bpf_experimental.h" + +struct val_t { + long b, c, d; +}; + +struct elem { + long sum; + struct val_t __percpu_kptr *pc; +}; + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __uint(max_entries, 1); + __type(key, int); + __type(value, struct elem); +} array SEC(".maps"); + +void bpf_rcu_read_lock(void) __ksym; +void bpf_rcu_read_unlock(void) __ksym; + +const volatile int nr_cpus; + +/* Initialize the percpu object */ +SEC("?fentry/bpf_fentry_test1") +int BPF_PROG(test_array_map_1) +{ + struct val_t __percpu_kptr *p; + struct elem *e; + int index = 0; + + e = bpf_map_lookup_elem(&array, &index); + if (!e) + return 0; + + p = bpf_percpu_obj_new(struct val_t); + if (!p) + return 0; + + p = bpf_kptr_xchg(&e->pc, p); + if (p) + bpf_percpu_obj_drop(p); + + return 0; +} + +/* Update percpu data */ +SEC("?fentry/bpf_fentry_test2") +int BPF_PROG(test_array_map_2) +{ + struct val_t __percpu_kptr *p; + struct val_t *v; + struct elem *e; + int index = 0; + + e = bpf_map_lookup_elem(&array, &index); + if (!e) + return 0; + + p = e->pc; + if (!p) + return 0; + + v = bpf_per_cpu_ptr(p, 0); + if (!v) + return 0; + v->c = 1; + v->d = 2; + + return 0; +} + +int cpu0_field_d, sum_field_c; + +/* Summarize percpu data */ +SEC("?fentry/bpf_fentry_test3") +int BPF_PROG(test_array_map_3) +{ + struct val_t __percpu_kptr *p; + int i, index = 0; + struct val_t *v; + struct elem *e; + + e = bpf_map_lookup_elem(&array, &index); + if (!e) + return 0; + + p = e->pc; + if (!p) + return 0; + + bpf_for(i, 0, nr_cpus) { + v = bpf_per_cpu_ptr(p, i); + if (v) { + if (i == 0) + cpu0_field_d = v->d; + sum_field_c += v->c; + } + } + + return 0; +} + +/* Explicitly free allocated percpu data */ +SEC("?fentry/bpf_fentry_test4") +int BPF_PROG(test_array_map_4) +{ + struct val_t __percpu_kptr *p; + struct elem *e; + int index = 0; + + e = bpf_map_lookup_elem(&array, &index); + if (!e) + return 0; + + /* delete */ + p = bpf_kptr_xchg(&e->pc, NULL); + if (p) { + bpf_percpu_obj_drop(p); + } + + return 0; +} + +SEC("?fentry.s/bpf_fentry_test1") +int BPF_PROG(test_array_map_10) +{ + struct val_t __percpu_kptr *p, *p1; + int i, index = 0; + struct val_t *v; + struct elem *e; + + e = bpf_map_lookup_elem(&array, &index); + if (!e) + return 0; + + bpf_rcu_read_lock(); + p = e->pc; + if (!p) { + p = bpf_percpu_obj_new(struct val_t); + if (!p) + goto out; + + p1 = bpf_kptr_xchg(&e->pc, p); + if (p1) { + /* race condition */ + bpf_percpu_obj_drop(p1); + } + + p = e->pc; + if (!p) + goto out; + } + + v = bpf_this_cpu_ptr(p); + v->c = 3; + v = bpf_this_cpu_ptr(p); + v->c = 0; + + v = bpf_per_cpu_ptr(p, 0); + if (!v) + goto out; + v->c = 1; + v->d = 2; + + /* delete */ + p1 = bpf_kptr_xchg(&e->pc, NULL); + if (!p1) + goto out; + + bpf_for(i, 0, nr_cpus) { + v = bpf_per_cpu_ptr(p, i); + if (v) { + if (i == 0) + cpu0_field_d = v->d; + sum_field_c += v->c; + } + } + + /* finally release p */ + bpf_percpu_obj_drop(p1); +out: + bpf_rcu_read_unlock(); + return 0; +} + +char _license[] SEC("license") = "GPL";