From: Joshua Hahn <joshua.hahn6@xxxxxxxxx>
Creates a cgroup with a single nice CPU hog process running.
fork() is called to generate the nice process because un-nicing is
not possible (see man nice(3)). If fork() was not used to generate
the CPU hog, we would run the rest of the cgroup selftest suite as a
nice process.
Signed-off-by: Joshua Hahn <joshua.hahnjy@xxxxxxxxx>
---
tools/testing/selftests/cgroup/test_cpu.c | 75 +++++++++++++++++++++++
1 file changed, 75 insertions(+)
diff --git a/tools/testing/selftests/cgroup/test_cpu.c b/tools/testing/selftests/cgroup/test_cpu.c
index dad2ed82f3ef..201ce14cb422 100644
--- a/tools/testing/selftests/cgroup/test_cpu.c
+++ b/tools/testing/selftests/cgroup/test_cpu.c
@@ -8,6 +8,7 @@
#include <pthread.h>
#include <stdio.h>
#include <time.h>
+#include <unistd.h>
#include "../kselftest.h"
#include "cgroup_util.h"
@@ -229,6 +230,79 @@ static int test_cpucg_stats(const char *root)
return ret;
}
+/*
+ * 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 (nice_usec == -1)
+ ret = KSFT_SKIP;
+ if (user_usec != 0 || nice_usec != 0)
+ goto cleanup;
+
+ /*
+ * 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,
+ };
+ char buf[64];
+ snprintf(buf, sizeof(buf), "%d", getpid());
+ if (cg_write(cpucg, "cgroup.procs", buf))
+ goto cleanup;
+
+ /* Try to keep niced CPU usage as constrained to hog_cpu as possible */
+ nice(1);
+ hog_cpus_timed(cpucg, param);
+ exit(0);
+ } else {
+ waitpid(pid, &status, 0);
+ if (!WIFEXITED(status))
+ 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 (!values_close(nice_usec, expected_nice_usec, 1))
+ goto cleanup;
+
+ ret = KSFT_PASS;
+ }
+
+cleanup:
+ cg_destroy(cpucg);
+ free(cpucg);
+
+ return ret;
+}
+
static int
run_cpucg_weight_test(
const char *root,
@@ -686,6 +760,7 @@ struct cpucg_test {
} tests[] = {
T(test_cpucg_subtree_control),
T(test_cpucg_stats),
+ T(test_cpucg_nice),
T(test_cpucg_weight_overprovisioned),
T(test_cpucg_weight_underprovisioned),
T(test_cpucg_nested_weight_overprovisioned),
--
2.43.5
