The cgroup cpu controller tests in
tools/testing/selftests/cgroup/test_cpu.c have some testcases that validate
the expected behavior of setting cpu.weight on cgroups, and then hogging
CPUs. What is still missing from the suite is a testcase that validates
nested cgroups. This patch adds test_cpucg_nested_weight_overprovisioned(),
which validates that a parent's cpu.weight will override its children if
they overcommit a host, and properly protect any sibling groups of that
parent.
Signed-off-by: David Vernet <void@xxxxxxxxxxxxx>
---
tools/testing/selftests/cgroup/test_cpu.c | 122 ++++++++++++++++++++++
1 file changed, 122 insertions(+)
diff --git a/tools/testing/selftests/cgroup/test_cpu.c b/tools/testing/selftests/cgroup/test_cpu.c
index 64f9ce91c992..fc90b4d0feb9 100644
--- a/tools/testing/selftests/cgroup/test_cpu.c
+++ b/tools/testing/selftests/cgroup/test_cpu.c
@@ -403,6 +403,127 @@ static int test_cpucg_weight_underprovisioned(const char *root)
underprovision_validate);
}
+/*
+ * First, this test creates the following hierarchy:
+ * A
+ * A/B cpu.weight = 1000
+ * A/C cpu.weight = 1000
+ * A/C/D cpu.weight = 5000
+ * A/C/E cpu.weight = 5000
+ *
+ * A separate process is then created for each leaf, which spawn nproc threads
+ * that burn a CPU for a few seconds.
+ *
+ * Once all of those processes have exited, we verify that each of the leaf
+ * cgroups have roughly the same usage from cpu.stat.
+ */
+static int
+test_cpucg_nested_weight_overprovisioned(const char *root)
+{
+ int ret = KSFT_FAIL, i;
+ char *parent = NULL, *child = NULL;
+ struct cpu_hogger leaf[3] = {NULL};
+ long nested_leaf_usage, child_usage;
+ int nprocs = get_nprocs();
+
+ parent = cg_name(root, "cpucg_test");
+ child = cg_name(parent, "cpucg_child");
+ if (!parent || !child)
+ goto cleanup;
+
+ if (cg_create(parent))
+ goto cleanup;
+ if (cg_write(parent, "cgroup.subtree_control", "+cpu"))
+ goto cleanup;
+
+ if (cg_create(child))
+ goto cleanup;
+ if (cg_write(child, "cgroup.subtree_control", "+cpu"))
+ goto cleanup;
+ if (cg_write(child, "cpu.weight", "1000"))
+ goto cleanup;
+
+ for (i = 0; i < ARRAY_SIZE(leaf); i++) {
+ const char *ancestor;
+ long weight;
+
+ if (i == 0) {
+ ancestor = parent;
+ weight = 1000;
+ } else {
+ ancestor = child;
+ weight = 5000;
+ }
+ leaf[i].cgroup = cg_name_indexed(ancestor, "cpucg_leaf", i);
+ if (!leaf[i].cgroup)
+ goto cleanup;
+
+ if (cg_create(leaf[i].cgroup))
+ goto cleanup;
+
+ if (cg_write_numeric(leaf[i].cgroup, "cpu.weight", weight))
+ goto cleanup;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(leaf); i++) {
+ pid_t pid;
+ struct cpu_hog_func_param param = {
+ .nprocs = nprocs,
+ .ts = {
+ .tv_sec = 10,
+ .tv_nsec = 0,
+ },
+ .clock_type = CPU_HOG_CLOCK_WALL,
+ };
+
+ pid = cg_run_nowait(leaf[i].cgroup, hog_cpus_timed,
+ (void *)¶m);
+ if (pid <= 0)
+ goto cleanup;
+ leaf[i].pid = pid;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(leaf); i++) {
+ int retcode;
+
+ waitpid(leaf[i].pid, &retcode, 0);
+ if (!WIFEXITED(retcode))
+ goto cleanup;
+ if (WEXITSTATUS(retcode))
+ goto cleanup;
+ }
+
+ for (i = 0; i < ARRAY_SIZE(leaf); i++) {
+ leaf[i].usage = cg_read_key_long(leaf[i].cgroup,
+ "cpu.stat", "usage_usec");
+ if (leaf[i].usage <= 0)
+ goto cleanup;
+ }
+
+ nested_leaf_usage = leaf[1].usage + leaf[2].usage;
+ if (!values_close(leaf[0].usage, nested_leaf_usage, 15))
+ goto cleanup;
+
+ child_usage = cg_read_key_long(child, "cpu.stat", "usage_usec");
+ if (child_usage <= 0)
+ goto cleanup;
+ if (!values_close(child_usage, nested_leaf_usage, 1))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+cleanup:
+ for (i = 0; i < ARRAY_SIZE(leaf); i++) {
+ cg_destroy(leaf[i].cgroup);
+ free(leaf[i].cgroup);
+ }
+ cg_destroy(child);
+ free(child);
+ cg_destroy(parent);
+ free(parent);
+
+ return ret;
+}
+
#define T(x) { x, #x }
struct cpucg_test {
int (*fn)(const char *root);
@@ -412,6 +533,7 @@ struct cpucg_test {
T(test_cpucg_stats),
T(test_cpucg_weight_overprovisioned),
T(test_cpucg_weight_underprovisioned),
+ T(test_cpucg_nested_weight_overprovisioned),
};
#undef T
--
2.30.2
