diff mbox series

[bpf-next,2/2] selftests/bpf: add tests for BPF_F_SHARE_PE

Message ID 20200929084750.419168-3-songliubraving@fb.com (mailing list archive)
State Changes Requested
Headers show
Series introduce BPF_F_SHARE_PE | expand

Commit Message

Song Liu Sept. 29, 2020, 8:47 a.m. UTC
Add tests for perf event array with and without BPF_F_SHARE_PE.

Add a perf event to array via fd mfd. Without BPF_F_SHARE_PE, the perf
event is removed when mfd is closed. With BPF_F_SHARE_PE, the perf event
is removed when the map is freed.

Signed-off-by: Song Liu <songliubraving@fb.com>
---
 .../bpf/prog_tests/perf_event_share.c         | 68 +++++++++++++++++++
 .../bpf/progs/test_perf_event_share.c         | 44 ++++++++++++
 2 files changed, 112 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/perf_event_share.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_perf_event_share.c

Comments

Daniel Borkmann Sept. 29, 2020, 2:08 p.m. UTC | #1
On 9/29/20 10:47 AM, Song Liu wrote:
> Add tests for perf event array with and without BPF_F_SHARE_PE.
> 
> Add a perf event to array via fd mfd. Without BPF_F_SHARE_PE, the perf
> event is removed when mfd is closed. With BPF_F_SHARE_PE, the perf event
> is removed when the map is freed.
> 
> Signed-off-by: Song Liu <songliubraving@fb.com>
[...]
> +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);
> +	if (CHECK(err < 0, "bpf_map_update_elem", "failed\n"))
> +		goto cleanup;
> +
> +	err = bpf_prog_test_run_opts(bpf_program__fd(prog), &opts);
> +	if (CHECK(err < 0, "bpf_prog_test_run_opts", "failed\n"))
> +		goto cleanup;
> +	if (CHECK(opts.retval != 0, "bpf_perf_event_read_value",
> +		  "failed with %d\n", opts.retval))
> +		goto cleanup;
> +
> +	/* 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"))
> +		goto cleanup;
> +
> +	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);
> +	}
> +
> +cleanup:
> +	close(pfd);

Why holding pfd until the end? The map should already hold a ref after update.
So you should be able to just do ...

err = bpf_map_update_elem(mfd, &key, &pfd, BPF_ANY);
close(pfd);

... and simplify cleanup.

> +}
> +
> +void test_perf_event_share(void)
> +{
> +	struct test_perf_event_share *skel;
> +
> +	skel = test_perf_event_share__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_perf_event_share__destroy(skel);
> +}
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/perf_event_share.c b/tools/testing/selftests/bpf/prog_tests/perf_event_share.c
new file mode 100644
index 0000000000000..a37cfdd047ea6
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/perf_event_share.c
@@ -0,0 +1,68 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2019 Facebook */
+#include <test_progs.h>
+#include <linux/bpf.h>
+#include "test_perf_event_share.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);
+	if (CHECK(err < 0, "bpf_map_update_elem", "failed\n"))
+		goto cleanup;
+
+	err = bpf_prog_test_run_opts(bpf_program__fd(prog), &opts);
+	if (CHECK(err < 0, "bpf_prog_test_run_opts", "failed\n"))
+		goto cleanup;
+	if (CHECK(opts.retval != 0, "bpf_perf_event_read_value",
+		  "failed with %d\n", opts.retval))
+		goto cleanup;
+
+	/* 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"))
+		goto cleanup;
+
+	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);
+	}
+
+cleanup:
+	close(pfd);
+}
+
+void test_perf_event_share(void)
+{
+	struct test_perf_event_share *skel;
+
+	skel = test_perf_event_share__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_perf_event_share__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_perf_event_share.c b/tools/testing/selftests/bpf/progs/test_perf_event_share.c
new file mode 100644
index 0000000000000..005bfe375352f
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_perf_event_share.c
@@ -0,0 +1,44 @@ 
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2020 Facebook
+#include "vmlinux.h"
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+
+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_SHARE_PE);  /* array_2 has BPF_F_SHARE_PE */
+} 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";