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@xxxxxx>
[...]
+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);
+}
