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Message-ID: <20240425140627.112728-1-andrea.righi@canonical.com>
Date: Thu, 25 Apr 2024 16:06:27 +0200
From: Andrea Righi <andrea.righi@...onical.com>
To: Andrii Nakryiko <andrii@...nel.org>,
Eduard Zingerman <eddyz87@...il.com>,
Mykola Lysenko <mykolal@...com>
Cc: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>,
Martin KaFai Lau <martin.lau@...ux.dev>,
Song Liu <song@...nel.org>,
Yonghong Song <yonghong.song@...ux.dev>,
John Fastabend <john.fastabend@...il.com>,
KP Singh <kpsingh@...nel.org>,
Stanislav Fomichev <sdf@...gle.com>,
Hao Luo <haoluo@...gle.com>,
Jiri Olsa <jolsa@...nel.org>,
Shuah Khan <shuah@...nel.org>,
linux-kernel@...r.kernel.org,
bpf@...r.kernel.org,
linux-kselftest@...r.kernel.org,
Andrea Righi <andrea.righi@...onical.com>
Subject: [PATCH v3] selftests/bpf: Add ring_buffer__consume_n test.
Add a testcase for the ring_buffer__consume_n() API.
The test produces multiple samples in a ring buffer, using a
sys_getpid() fentry prog, and consumes them from user-space in batches,
rather than consuming all of them greedily, like ring_buffer__consume()
does.
Link: https://lore.kernel.org/lkml/CAEf4BzaR4zqUpDmj44KNLdpJ=Tpa97GrvzuzVNO5nM6b7oWd1w@mail.gmail.com
Signed-off-by: Andrea Righi <andrea.righi@...onical.com>
---
tools/testing/selftests/bpf/Makefile | 2 +-
.../selftests/bpf/prog_tests/ringbuf.c | 64 +++++++++++++++++++
.../selftests/bpf/progs/test_ringbuf_n.c | 47 ++++++++++++++
3 files changed, 112 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/progs/test_ringbuf_n.c
ChangeLog v2 -> v3:
- move skel_n inside ringbuf_n_subtest()
ChangeLog v1 -> v2:
- replace CHECK() with ASSERT_EQ()
- fix skel -> skel_n
- drop unused "seq" field from struct sample
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index edc73f8f5aef..6332277edeca 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -455,7 +455,7 @@ LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h \
LSKELS := fentry_test.c fexit_test.c fexit_sleep.c atomics.c \
trace_printk.c trace_vprintk.c map_ptr_kern.c \
core_kern.c core_kern_overflow.c test_ringbuf.c \
- test_ringbuf_map_key.c
+ test_ringbuf_n.c test_ringbuf_map_key.c
# Generate both light skeleton and libbpf skeleton for these
LSKELS_EXTRA := test_ksyms_module.c test_ksyms_weak.c kfunc_call_test.c \
diff --git a/tools/testing/selftests/bpf/prog_tests/ringbuf.c b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
index 48c5695b7abf..2f064d6952f0 100644
--- a/tools/testing/selftests/bpf/prog_tests/ringbuf.c
+++ b/tools/testing/selftests/bpf/prog_tests/ringbuf.c
@@ -13,6 +13,7 @@
#include <linux/perf_event.h>
#include <linux/ring_buffer.h>
#include "test_ringbuf.lskel.h"
+#include "test_ringbuf_n.lskel.h"
#include "test_ringbuf_map_key.lskel.h"
#define EDONE 7777
@@ -326,6 +327,67 @@ static void ringbuf_subtest(void)
test_ringbuf_lskel__destroy(skel);
}
+/*
+ * Test ring_buffer__consume_n() by producing N_TOT_SAMPLES samples in the ring
+ * buffer, via getpid(), and consuming them in chunks of N_SAMPLES.
+ */
+#define N_TOT_SAMPLES 32
+#define N_SAMPLES 4
+
+/* Sample value to verify the callback validity */
+#define SAMPLE_VALUE 42L
+
+static int process_n_sample(void *ctx, void *data, size_t len)
+{
+ struct sample *s = data;
+
+ ASSERT_EQ(s->value, SAMPLE_VALUE, "sample_value");
+
+ return 0;
+}
+
+static void ringbuf_n_subtest(void)
+{
+ struct test_ringbuf_n_lskel *skel_n;
+ int err, i;
+
+ skel_n = test_ringbuf_n_lskel__open();
+ if (!ASSERT_OK_PTR(skel_n, "test_ringbuf_n_lskel__open"))
+ return;
+
+ skel_n->maps.ringbuf.max_entries = getpagesize();
+ skel_n->bss->pid = getpid();
+
+ err = test_ringbuf_n_lskel__load(skel_n);
+ if (!ASSERT_OK(err, "test_ringbuf_n_lskel__load"))
+ goto cleanup;
+
+ ringbuf = ring_buffer__new(skel_n->maps.ringbuf.map_fd,
+ process_n_sample, NULL, NULL);
+ if (!ASSERT_OK_PTR(ringbuf, "ring_buffer__new"))
+ goto cleanup;
+
+ err = test_ringbuf_n_lskel__attach(skel_n);
+ if (!ASSERT_OK(err, "test_ringbuf_n_lskel__attach"))
+ goto cleanup_ringbuf;
+
+ /* Produce N_TOT_SAMPLES samples in the ring buffer by calling getpid() */
+ skel_n->bss->value = SAMPLE_VALUE;
+ for (i = 0; i < N_TOT_SAMPLES; i++)
+ syscall(__NR_getpgid);
+
+ /* Consume all samples from the ring buffer in batches of N_SAMPLES */
+ for (i = 0; i < N_TOT_SAMPLES; i += err) {
+ err = ring_buffer__consume_n(ringbuf, N_SAMPLES);
+ ASSERT_EQ(err, N_SAMPLES, "rb_consume");
+ }
+
+cleanup_ringbuf:
+ ring_buffer__free(ringbuf);
+cleanup:
+ test_ringbuf_n_lskel__destroy(skel_n);
+}
+
static int process_map_key_sample(void *ctx, void *data, size_t len)
{
struct sample *s;
@@ -384,6 +446,8 @@ void test_ringbuf(void)
{
if (test__start_subtest("ringbuf"))
ringbuf_subtest();
+ if (test__start_subtest("ringbuf_n"))
+ ringbuf_n_subtest();
if (test__start_subtest("ringbuf_map_key"))
ringbuf_map_key_subtest();
}
diff --git a/tools/testing/selftests/bpf/progs/test_ringbuf_n.c b/tools/testing/selftests/bpf/progs/test_ringbuf_n.c
new file mode 100644
index 000000000000..8669eb42dbe0
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_ringbuf_n.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2024 Andrea Righi <andrea.righi@...onical.com>
+
+#include <linux/bpf.h>
+#include <sched.h>
+#include <unistd.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+#define TASK_COMM_LEN 16
+
+struct sample {
+ int pid;
+ long value;
+ char comm[16];
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_RINGBUF);
+} ringbuf SEC(".maps");
+
+int pid = 0;
+long value = 0;
+
+SEC("fentry/" SYS_PREFIX "sys_getpgid")
+int test_ringbuf_n(void *ctx)
+{
+ int cur_pid = bpf_get_current_pid_tgid() >> 32;
+ struct sample *sample;
+
+ if (cur_pid != pid)
+ return 0;
+
+ sample = bpf_ringbuf_reserve(&ringbuf, sizeof(*sample), 0);
+ if (!sample)
+ return 0;
+
+ sample->pid = pid;
+ sample->value = value;
+ bpf_get_current_comm(sample->comm, sizeof(sample->comm));
+
+ bpf_ringbuf_submit(sample, 0);
+
+ return 0;
+}
--
2.43.0
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