diff mbox series

[v3,bpf-next,2/2] selftests/bpf: add tests for BPF_F_PRESERVE_ELEMS

Message ID 20200930152058.167985-3-songliubraving@fb.com (mailing list archive)
State Superseded
Headers show
Series introduce BPF_F_PRESERVE_ELEMS | expand

Commit Message

Song Liu Sept. 30, 2020, 3:20 p.m. UTC 
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 <songliubraving@fb.com>
---
 .../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

Comments

Alexei Starovoitov Sept. 30, 2020, 7:26 p.m. UTC | #1 
On Wed, Sep 30, 2020 at 08:20:58AM -0700, Song Liu wrote:
> 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"

Does it actually need vmlinux.h ?
Just checking to make sure it compiles on older kernels.

> +#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_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);

Please remove printk from the tests. It only spams the trace_pipe.

> +	return ret;

The return code is already checked as far as I can see.
That's enough to pass/fail the test, right?
Song Liu Sept. 30, 2020, 9:20 p.m. UTC | #2 
> On Sep 30, 2020, at 12:26 PM, Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> 
> On Wed, Sep 30, 2020 at 08:20:58AM -0700, Song Liu wrote:
>> 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"
> 
> Does it actually need vmlinux.h ?
> Just checking to make sure it compiles on older kernels.

We can include linux/bpf.h instead. 

[...]

>> +	long ret;
>> +
>> +	ret = bpf_perf_event_read_value(&array_2, 0, &val, sizeof(val));
>> +	bpf_printk("read_array_2 returns %ld", ret);
> 
> Please remove printk from the tests. It only spams the trace_pipe.
> 
>> +	return ret;
> 
> The return code is already checked as far as I can see.
> That's enough to pass/fail the test, right?

Yes, we can remove the bpf_printk() here. Fixing this in v4.

Thanks,
Song
diff mbox series

Patch

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 <test_progs.h>
+#include <linux/bpf.h>
+#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 <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_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";