cgroup: Add test_cpucg_max() testcase

The cgroup cpu controller test suite has a number of testcases that
validate the expected behavior of the cpu.weight knob, but none for
cpu.max. This testcase fixes that by adding a testcase for cpu.max as well.

Signed-off-by: David Vernet <void@manifault.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

diff --git a/tools/testing/selftests/cgroup/test_cpu.c b/tools/testing/selftests/cgroup/test_cpu.c
index de6289814c2392ccbbffa7409b0876753219fe1b..715922c15c78f930f56e6aed0e94b8a94223da6b 100644 (file)
--- a/tools/testing/selftests/cgroup/test_cpu.c
+++ b/tools/testing/selftests/cgroup/test_cpu.c
@@ -564,6 +564,59 @@ test_cpucg_nested_weight_underprovisioned(const char *root)
        return run_cpucg_nested_weight_test(root, false);
 }
 
+/*
+ * This test creates a cgroup with some maximum value within a period, and
+ * verifies that a process in the cgroup is not overscheduled.
+ */
+static int test_cpucg_max(const char *root)
+{
+       int ret = KSFT_FAIL;
+       long usage_usec, user_usec;
+       long usage_seconds = 1;
+       long expected_usage_usec = usage_seconds * USEC_PER_SEC;
+       char *cpucg;
+
+       cpucg = cg_name(root, "cpucg_test");
+       if (!cpucg)
+               goto cleanup;
+
+       if (cg_create(cpucg))
+               goto cleanup;
+
+       if (cg_write(cpucg, "cpu.max", "1000"))
+               goto cleanup;
+
+       struct cpu_hog_func_param param = {
+               .nprocs = 1,
+               .ts = {
+                       .tv_sec = usage_seconds,
+                       .tv_nsec = 0,
+               },
+               .clock_type = CPU_HOG_CLOCK_WALL,
+       };
+       if (cg_run(cpucg, hog_cpus_timed, (void *)&param))
+               goto cleanup;
+
+       usage_usec = cg_read_key_long(cpucg, "cpu.stat", "usage_usec");
+       user_usec = cg_read_key_long(cpucg, "cpu.stat", "user_usec");
+       if (user_usec <= 0)
+               goto cleanup;
+
+       if (user_usec >= expected_usage_usec)
+               goto cleanup;
+
+       if (values_close(usage_usec, expected_usage_usec, 95))
+               goto cleanup;
+
+       ret = KSFT_PASS;
+
+cleanup:
+       cg_destroy(cpucg);
+       free(cpucg);
+
+       return ret;
+}
+
 #define T(x) { x, #x }
 struct cpucg_test {
        int (*fn)(const char *root);
@@ -575,6 +628,7 @@ struct cpucg_test {
        T(test_cpucg_weight_underprovisioned),
        T(test_cpucg_nested_weight_overprovisioned),
        T(test_cpucg_nested_weight_underprovisioned),
+       T(test_cpucg_max),
 };
 #undef T