rcutorture: Permit holding off CPU-hotplug operations during boot
When rcutorture is started automatically at boot time, it might well
also start CPU-hotplug operations at that time, which might not be
desirable. This commit therefore adds an rcutorture parameter that
allows CPU-hotplug operations to be held off for the specified number
of seconds after the start of boot.
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index a52b321..2914caf 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -65,6 +65,7 @@
static int fqs_holdoff; /* Hold time within burst (us). */
static int fqs_stutter = 3; /* Wait time between bursts (s). */
static int onoff_interval; /* Wait time between CPU hotplugs, 0=disable. */
+static int onoff_holdoff; /* Seconds after boot before CPU hotplugs. */
static int shutdown_secs; /* Shutdown time (s). <=0 for no shutdown. */
static int test_boost = 1; /* Test RCU prio boost: 0=no, 1=maybe, 2=yes. */
static int test_boost_interval = 7; /* Interval between boost tests, seconds. */
@@ -95,6 +96,8 @@
MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
module_param(onoff_interval, int, 0444);
MODULE_PARM_DESC(onoff_interval, "Time between CPU hotplugs (s), 0=disable");
+module_param(onoff_holdoff, int, 0444);
+MODULE_PARM_DESC(onoff_holdoff, "Time after boot before CPU hotplugs (s)");
module_param(shutdown_secs, int, 0444);
MODULE_PARM_DESC(shutdown_secs, "Shutdown time (s), zero to disable.");
module_param(test_boost, int, 0444);
@@ -1300,13 +1303,13 @@
"fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
"test_boost=%d/%d test_boost_interval=%d "
"test_boost_duration=%d shutdown_secs=%d "
- "onoff_interval=%d\n",
+ "onoff_interval=%d onoff_holdoff=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
stat_interval, verbose, test_no_idle_hz, shuffle_interval,
stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
test_boost, cur_ops->can_boost,
test_boost_interval, test_boost_duration, shutdown_secs,
- onoff_interval);
+ onoff_interval, onoff_holdoff);
}
static struct notifier_block rcutorture_shutdown_nb = {
@@ -1410,6 +1413,11 @@
for_each_online_cpu(cpu)
maxcpu = cpu;
WARN_ON(maxcpu < 0);
+ if (onoff_holdoff > 0) {
+ VERBOSE_PRINTK_STRING("rcu_torture_onoff begin holdoff");
+ schedule_timeout_interruptible(onoff_holdoff * HZ);
+ VERBOSE_PRINTK_STRING("rcu_torture_onoff end holdoff");
+ }
while (!kthread_should_stop()) {
cpu = (rcu_random(&rand) >> 4) % (maxcpu + 1);
if (cpu_online(cpu) && cpu_is_hotpluggable(cpu)) {