Re: [PATCH v3 2/2] selftests: sched: skip cs_prctl_test for systems with core scheduling disabled

On 2/26/25 01:39, Sinadin Shan wrote:

For kernels with CONFIG_SCHED_CORE=n, the sched selftest cs_prctl_test fails with "Not a core sched system" error. Change this to gracefully skip the test for systems with core scheduling disabled. Exiting early would also ensure failures reported in obtaining cookie are valid failures and not because core scheduling isn't supported.

Skip cs_prctl_test for systems with CONFIG_SCHED_CORE=n

Signed-off-by: Sinadin Shan sinadin.shan@oracle.com

tools/testing/selftests/sched/cs_prctl_test.c | 34 ++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/sched/cs_prctl_test.c b/tools/testing/selftests/sched/cs_prctl_test.c index 52d97fae4dbd8..5b0047b50e640 100644 --- a/tools/testing/selftests/sched/cs_prctl_test.c +++ b/tools/testing/selftests/sched/cs_prctl_test.c @@ -109,6 +109,36 @@ static void handle_usage(int rc, char *msg) exit(rc); } +static void check_core_sched(void) +{

• unsigned long long cookie;
• int ret, num_max_process;
• char buffer[32];
• FILE *fp = fopen("/proc/sys/kernel/pid_max", "r");
• if (fp == NULL) {

• perror("Failed to obtain max process number");
  

• exit(EXIT_FAILURE);
  

• }
• if (fgets(buffer, sizeof(buffer), fp) == NULL) {

• fclose(fp);
  

• exit(EXIT_FAILURE);
  

• }
• num_max_process = atoi(buffer);
• fclose(fp);
• ret = prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, num_max_process+1, PIDTYPE_PID,

• 	(unsigned long)&cookie);
  

• if (ret == -1 && errno != ESRCH) {

• perror("prctl failed");
  

• printf("Core sched not supported, hence skipping tests\n");
  

• exit(4);
  

• }

+}

• static unsigned long get_cs_cookie(int pid) { unsigned long long cookie;

@@ -117,7 +147,7 @@ static unsigned long get_cs_cookie(int pid) ret = prctl(PR_SCHED_CORE, PR_SCHED_CORE_GET, pid, PIDTYPE_PID, (unsigned long)&cookie); if (ret) {

• printf("Not a core sched system\n");
  

• printf("Failed to get cookie\n");
  

  return -1UL; }

@@ -270,6 +300,8 @@ int main(int argc, char *argv[]) if (keypress) delay = -1;

• check_core_sched();
• srand(time(NULL));

/* put into separate process group */

This works for me in my workflow. I don't know full selftest framework or how to trigger it.

When CONFIG_SCHED_CORE=n ----------------------------- ./cs_prctl_test prctl failed: Invalid argument Core sched not supported, hence skipping tests

When CONFIG_SCHED_CORE=y ----------------------------- ./cs_prctl_test (369) PASSED: _prctl(PR_SCHED_CORE, PR_SCHED_CORE_MAX, 0, PIDTYPE_PGID, 0) < 0 && errno == EINVAL -1 = prctl(62, 2, 0, 2, 1) (372) PASSED: _prctl(PR_SCHED_CORE, PR_SCHED_CORE_SHARE_TO, 0, PIDTYPE_PGID, 1) < 0 && errno == EINVAL SUCCESS !!!

So for this patch, Tested-by: Shrikanth Hegde sshegde@linux.ibm.com