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rcu: Add rcutorture system-shutdown capability 

Although it is easy to run rcutorture tests under KVM, there is currently
no nice way to run such a test for a fixed time period, collect all of
the rcutorture data, and then shut the system down cleanly.  This commit
therefore adds an rcutorture module parameter named "shutdown_secs" that
specified the run duration in seconds, after which rcutorture terminates
the test and powers the system down.  The default value for "shutdown_secs"
is zero, which disables shutdown.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2011-11-04 11:44:12 -07:00 committed by Paul E. McKenney
parent b807fbff31
commit d5f546d834
2 changed files with 69 additions and 4 deletions
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5
Documentation/RCU/torture.txt
View File

@ -66,6 +66,11 @@ shuffle_interval
to a particular subset of the CPUs, defaults to 3 seconds.
Used in conjunction with test_no_idle_hz.
shutdown_secs The number of seconds to run the test before terminating
the test and powering off the system. The default is
zero, which disables test termination and system shutdown.
This capability is useful for automated testing.
stat_interval The number of seconds between output of torture
statistics (via printk()). Regardless of the interval,
statistics are printed when the module is unloaded.

68
kernel/rcutorture.c
View File

@ -61,9 +61,10 @@ static int test_no_idle_hz; /* Test RCU's support for tickless idle CPUs. */
static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
static int stutter = 5; /* Start/stop testing interval (in sec) */
static int irqreader = 1; /* RCU readers from irq (timers). */
static int fqs_duration = 0; /* Duration of bursts (us), 0 to disable. */
static int fqs_holdoff = 0; /* Hold time within burst (us). */
static int fqs_duration; /* Duration of bursts (us), 0 to disable. */
static int fqs_holdoff; /* Hold time within burst (us). */
static int fqs_stutter = 3; /* Wait time between bursts (s). */
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. */
static int test_boost_duration = 4; /* Duration of each boost test, seconds. */
@ -91,6 +92,8 @@ module_param(fqs_holdoff, int, 0444);
MODULE_PARM_DESC(fqs_holdoff, "Holdoff time within fqs bursts (us)");
module_param(fqs_stutter, int, 0444);
MODULE_PARM_DESC(fqs_stutter, "Wait time between fqs bursts (s)");
module_param(shutdown_secs, int, 0444);
MODULE_PARM_DESC(shutdown_secs, "Shutdown time (s), zero to disable.");
module_param(test_boost, int, 0444);
MODULE_PARM_DESC(test_boost, "Test RCU prio boost: 0=no, 1=maybe, 2=yes.");
module_param(test_boost_interval, int, 0444);
@ -119,6 +122,7 @@ static struct task_struct *shuffler_task;
static struct task_struct *stutter_task;
static struct task_struct *fqs_task;
static struct task_struct *boost_tasks[NR_CPUS];
static struct task_struct *shutdown_task;
#define RCU_TORTURE_PIPE_LEN 10
@ -167,6 +171,7 @@ int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
#define rcu_can_boost() 0
#endif /* #else #if defined(CONFIG_RCU_BOOST) && !defined(CONFIG_HOTPLUG_CPU) */
static unsigned long shutdown_time; /* jiffies to system shutdown. */
static unsigned long boost_starttime; /* jiffies of next boost test start. */
DEFINE_MUTEX(boost_mutex); /* protect setting boost_starttime */
/* and boost task create/destroy. */
@ -182,6 +187,9 @@ static int fullstop = FULLSTOP_RMMOD;
*/
static DEFINE_MUTEX(fullstop_mutex);
/* Forward reference. */
static void rcu_torture_cleanup(void);
/*
* Detect and respond to a system shutdown.
*/
@ -1250,12 +1258,12 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag)
"shuffle_interval=%d stutter=%d irqreader=%d "
"fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
"test_boost=%d/%d test_boost_interval=%d "
"test_boost_duration=%d\n",
"test_boost_duration=%d shutdown_secs=%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);
test_boost_interval, test_boost_duration, shutdown_secs);
}
static struct notifier_block rcutorture_shutdown_nb = {
@ -1305,6 +1313,43 @@ static int rcutorture_booster_init(int cpu)
return 0;
}
/*
* Cause the rcutorture test to shutdown the system after the test has
* run for the time specified by the shutdown_secs module parameter.
*/
static int
rcu_torture_shutdown(void *arg)
{
long delta;
unsigned long jiffies_snap;
VERBOSE_PRINTK_STRING("rcu_torture_shutdown task started");
jiffies_snap = ACCESS_ONCE(jiffies);
while (ULONG_CMP_LT(jiffies_snap, shutdown_time) &&
!kthread_should_stop()) {
delta = shutdown_time - jiffies_snap;
if (verbose)
printk(KERN_ALERT "%s" TORTURE_FLAG
"rcu_torture_shutdown task: %lu "
"jiffies remaining\n",
torture_type, delta);
schedule_timeout_interruptible(delta);
jiffies_snap = ACCESS_ONCE(jiffies);
}
if (ULONG_CMP_LT(jiffies, shutdown_time)) {
VERBOSE_PRINTK_STRING("rcu_torture_shutdown task stopping");
return 0;
}
/* OK, shut down the system. */
VERBOSE_PRINTK_STRING("rcu_torture_shutdown task shutting down system");
shutdown_task = NULL; /* Avoid self-kill deadlock. */
rcu_torture_cleanup(); /* Get the success/failure message. */
kernel_power_off(); /* Shut down the system. */
return 0;
}
static int rcutorture_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu)
{
@ -1409,6 +1454,10 @@ rcu_torture_cleanup(void)
for_each_possible_cpu(i)
rcutorture_booster_cleanup(i);
}
if (shutdown_task != NULL) {
VERBOSE_PRINTK_STRING("Stopping rcu_torture_shutdown task");
kthread_stop(shutdown_task);
}
/* Wait for all RCU callbacks to fire. */
@ -1625,6 +1674,17 @@ rcu_torture_init(void)
}
}
}
if (shutdown_secs > 0) {
shutdown_time = jiffies + shutdown_secs * HZ;
shutdown_task = kthread_run(rcu_torture_shutdown, NULL,
"rcu_torture_shutdown");
if (IS_ERR(shutdown_task)) {
firsterr = PTR_ERR(shutdown_task);
VERBOSE_PRINTK_ERRSTRING("Failed to create shutdown");
shutdown_task = NULL;
goto unwind;
}
}
register_reboot_notifier(&rcutorture_shutdown_nb);
rcutorture_record_test_transition();
mutex_unlock(&fullstop_mutex);