From d5f546d834ddc44539651e9955eb3577b0a3eb8b Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 4 Nov 2011 11:44:12 -0700 Subject: 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 Signed-off-by: Paul E. McKenney --- kernel/rcutorture.c | 68 +++++++++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 64 insertions(+), 4 deletions(-) (limited to 'kernel/rcutorture.c') diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c index df35228e743b..ce84091291b5 100644 --- a/kernel/rcutorture.c +++ b/kernel/rcutorture.c @@ -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); -- cgit v1.2.3-58-ga151