On Mon, Sep 23, 2024 at 07:20:06AM GMT, Joshua Hahn <joshua.hah...@gmail.com> wrote: > +/* > + * Creates a nice process that consumes CPU and checks that the elapsed > + * usertime in the cgroup is close to the expected time. > + */ > +static int test_cpucg_nice(const char *root) > +{ > + int ret = KSFT_FAIL; > + int status; > + long user_usec, nice_usec; > + long usage_seconds = 2; > + long expected_nice_usec = usage_seconds * USEC_PER_SEC; > + char *cpucg; > + pid_t pid; > + > + cpucg = cg_name(root, "cpucg_test"); > + if (!cpucg) > + goto cleanup; > + > + if (cg_create(cpucg)) > + goto cleanup; > + > + user_usec = cg_read_key_long(cpucg, "cpu.stat", "user_usec"); > + nice_usec = cg_read_key_long(cpucg, "cpu.stat", "nice_usec"); > + if (user_usec != 0 || nice_usec != 0) > + goto cleanup;
Can you please distinguish a check between non-zero nice_usec and non-existent nice_usec (KSFT_FAIL vs KSFT_SKIP)? So that the selftest is usable on older kernels too. > + > + /* > + * We fork here to create a new process that can be niced without > + * polluting the nice value of other selftests > + */ > + pid = fork(); > + if (pid < 0) { > + goto cleanup; > + } else if (pid == 0) { > + struct cpu_hog_func_param param = { > + .nprocs = 1, > + .ts = { > + .tv_sec = usage_seconds, > + .tv_nsec = 0, > + }, > + .clock_type = CPU_HOG_CLOCK_PROCESS, > + }; > + > + /* Try to keep niced CPU usage as constrained to hog_cpu as > possible */ > + nice(1); > + cg_run(cpucg, hog_cpus_timed, (void *)¶m); Notice that cg_run() does fork itself internally. So you can call hog_cpus_timed(cpucg, (void *)¶m) directly, no need for the fork with cg_run(). (Alternatively substitute fork in this test with the fork in cg_run() but with extension of cpu_hog_func_params with the nice value.) Thanks, Michal
signature.asc
Description: PGP signature