torture: Affinity waiter tasks away from hotpluggable CPU
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcu/waketorture.c b/kernel/rcu/waketorture.c
index f9843eb..68be404 100644
--- a/kernel/rcu/waketorture.c
+++ b/kernel/rcu/waketorture.c
@@ -236,7 +236,9 @@
*/
static int wake_torture_onoff(void *args)
{
+ cpumask_var_t cm;
int cpu;
+ int i;
VERBOSE_TOROUT_STRING("wake_torture_onoff task started");
if (onoff_holdoff > 0) {
@@ -244,6 +246,11 @@
schedule_timeout_interruptible(onoff_holdoff * HZ);
VERBOSE_TOROUT_STRING("wake_torture_onoff end holdoff");
}
+
+ /*
+ * Find the last hotpluggable CPU, and affinity the waiter
+ * tasks elsewhere.
+ */
for_each_online_cpu(cpu) {
if (cpu_is_hotpluggable(cpu))
onoff_cpu = cpu;
@@ -257,6 +264,18 @@
}
}
pr_alert("%s" TORTURE_FLAG " wake_torture_onoff: onoff_cpu: %d\n", torture_type, onoff_cpu);
+ if (!zalloc_cpumask_var(&cm, GFP_KERNEL)) {
+ VERBOSE_TOROUT_STRING("wake_torture_onoff: Out of memory, no affinity");
+ } else {
+ cpumask_copy(cm, cpu_online_mask);
+ cpumask_clear_cpu(onoff_cpu, cm);
+ if (cpumask_weight(cm) == 0)
+ cpumask_setall(cm);
+ for (i = 0; i < nrealwaiters; i++)
+ set_cpus_allowed_ptr(waiter_tasks[i], cm);
+ }
+
+ /* Cycle the victim CPU online and offline! */
while (!torture_must_stop() && onoff_cpu >= 0) {
if (!torture_offline(onoff_cpu,
&n_offline_attempts, &n_offline_successes,
