2026年1月24日 04:47, "JP Kobryn" <[email protected] mailto:[email protected]?to=%22JP%20Kobryn%22%20%3Cinwardvessel%40gmail.com%3E > 写到:
> > Hi Hui, > > On 1/23/26 1:00 AM, Hui Zhu wrote: > > > > > From: Hui Zhu <[email protected]> > > Add a comprehensive selftest suite for the `memcg_bpf_ops` > > functionality. These tests validate that BPF programs can correctly > > influence memory cgroup throttling behavior by implementing the new > > hooks. > > The test suite is added in `prog_tests/memcg_ops.c` and covers > > several key scenarios: > > 1. `test_memcg_ops_over_high`: > > Verifies that a BPF program can trigger throttling on a low-priority > > cgroup by returning a delay from the `get_high_delay_ms` hook when a > > high-priority cgroup is under pressure. > > 2. `test_memcg_ops_below_low_over_high`: > > Tests the combination of the `below_low` and `get_high_delay_ms` > > hooks, ensuring they work together as expected. > > 3. `test_memcg_ops_below_min_over_high`: > > Validates the interaction between the `below_min` and > > `get_high_delay_ms` hooks. > > The test framework sets up a cgroup hierarchy with high and low > > priority groups, attaches BPF programs, runs memory-intensive > > workloads, and asserts that the observed throttling (measured by > > workload execution time) matches expectations. > > The BPF program (`progs/memcg_ops.c`) uses a tracepoint on > > `memcg:count_memcg_events` (specifically PGFAULT) to detect memory > > pressure and trigger the appropriate hooks in response. This test > > suite provides essential validation for the new memory control > > mechanisms. > > Signed-off-by: Geliang Tang <[email protected]> > > Signed-off-by: Hui Zhu <[email protected]> > > --- > > > [..] > > > > > diff --git a/tools/testing/selftests/bpf/prog_tests/memcg_ops.c > > b/tools/testing/selftests/bpf/prog_tests/memcg_ops.c > > new file mode 100644 > > index 000000000000..9a8d16296f2d > > --- /dev/null > > +++ b/tools/testing/selftests/bpf/prog_tests/memcg_ops.c > > @@ -0,0 +1,537 @@ > > > [..] > > > > > + > > +static void > > +real_test_memcg_ops_child_work(const char *cgroup_path, > > + char *data_filename, > > + char *time_filename, > > + int read_times) > > +{ > > + struct timeval start, end; > > + double elapsed; > > + FILE *fp; > > + > > + if (!ASSERT_OK(join_parent_cgroup(cgroup_path), "join_parent_cgroup")) > > + goto out; > > + > > + if (env.verbosity >= VERBOSE_NORMAL) > > + printf("%s %d begin\n", __func__, getpid()); > > + > > + gettimeofday(&start, NULL); > > + > > + if (!ASSERT_OK(write_file(data_filename), "write_file")) > > + goto out; > > + > > + if (env.verbosity >= VERBOSE_NORMAL) > > + printf("%s %d write_file done\n", __func__, getpid()); > > + > > + if (!ASSERT_OK(read_file(data_filename, read_times), "read_file")) > > + goto out; > > + > > + gettimeofday(&end, NULL); > > + > > + elapsed = (end.tv_sec - start.tv_sec) + > > + (end.tv_usec - start.tv_usec) / 1000000.0; > > + > > + if (env.verbosity >= VERBOSE_NORMAL) > > + printf("%s %d end %.6f\n", __func__, getpid(), elapsed); > > + > > + fp = fopen(time_filename, "w"); > > + if (!ASSERT_OK_PTR(fp, "fopen")) > > + goto out; > > + fprintf(fp, "%.6f", elapsed); > > + fclose(fp); > > + > > +out: > > + exit(0); > > +} > > + > > > [..] > > > > > +static void real_test_memcg_ops(int read_times) > > +{ > > + int ret; > > + char data_file1[] = "/tmp/test_data_XXXXXX"; > > + char data_file2[] = "/tmp/test_data_XXXXXX"; > > + char time_file1[] = "/tmp/test_time_XXXXXX"; > > + char time_file2[] = "/tmp/test_time_XXXXXX"; > > + pid_t pid1, pid2; > > + double time1, time2; > > + > > + ret = mkstemp(data_file1); > > + if (!ASSERT_GT(ret, 0, "mkstemp")) > > + return; > > + close(ret); > > + ret = mkstemp(data_file2); > > + if (!ASSERT_GT(ret, 0, "mkstemp")) > > + goto cleanup_data_file1; > > + close(ret); > > + ret = mkstemp(time_file1); > > + if (!ASSERT_GT(ret, 0, "mkstemp")) > > + goto cleanup_data_file2; > > + close(ret); > > + ret = mkstemp(time_file2); > > + if (!ASSERT_GT(ret, 0, "mkstemp")) > > + goto cleanup_time_file1; > > + close(ret); > > + > > + pid1 = fork(); > > + if (!ASSERT_GE(pid1, 0, "fork")) > > + goto cleanup; > > + if (pid1 == 0) > > + real_test_memcg_ops_child_work(CG_LOW_DIR, > > + data_file1, > > + time_file1, > > + read_times); > > > Would it be better to call exit() after real_test_memcg_ops_child_work() > instead of within it? This way the fork/exit/wait logic is contained in > the same scope making the lifetimes easier to track. I had to go back > and search for the call to exit() since at a glance this function > appears to proceed to call fork() and waitpid() from within both parent > and child procs (though it really does not). > I will fix it. Best, Hui
