1 files changed, 95 insertions, 6 deletions

diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 33acc424667e..27003e2421c7 100644
--- a/kernel/rcutorture.c
+++ b/kernel/rcutorture.c
@@ -57,7 +57,8 @@ static int stat_interval;	/* Interval between stats, in seconds. */
 				/*  Defaults to "only at end of test". */
 static int verbose;		/* Print more debug info. */
 static int test_no_idle_hz;	/* Test RCU's support for tickless idle CPUs. */
-static int shuffle_interval = 5; /* Interval between shuffles (in sec)*/
+static int shuffle_interval = 3; /* Interval between shuffles (in sec)*/
+static int stutter = 5;		/* Start/stop testing interval (in sec) */
 static char *torture_type = "rcu"; /* What RCU implementation to torture. */
 
 module_param(nreaders, int, 0444);
@@ -72,6 +73,8 @@ module_param(test_no_idle_hz, bool, 0444);
 MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
 module_param(shuffle_interval, int, 0444);
 MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
+module_param(stutter, int, 0444);
+MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
 module_param(torture_type, charp, 0444);
 MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
 
@@ -91,6 +94,7 @@ static struct task_struct **fakewriter_tasks;
 static struct task_struct **reader_tasks;
 static struct task_struct *stats_task;
 static struct task_struct *shuffler_task;
+static struct task_struct *stutter_task;
 
 #define RCU_TORTURE_PIPE_LEN 10
 
@@ -119,6 +123,15 @@ static atomic_t n_rcu_torture_mberror;
 static atomic_t n_rcu_torture_error;
 static struct list_head rcu_torture_removed;
 
+static int stutter_pause_test = 0;
+
+#if defined(MODULE) || defined(CONFIG_RCU_TORTURE_TEST_RUNNABLE)
+#define RCUTORTURE_RUNNABLE_INIT 1
+#else
+#define RCUTORTURE_RUNNABLE_INIT 0
+#endif
+int rcutorture_runnable = RCUTORTURE_RUNNABLE_INIT;
+
 /*
  * Allocate an element from the rcu_tortures pool.
  */
@@ -179,6 +192,13 @@ rcu_random(struct rcu_random_state *rrsp)
 	return swahw32(rrsp->rrs_state);
 }
 
+static void
+rcu_stutter_wait(void)
+{
+	while (stutter_pause_test || !rcutorture_runnable)
+		schedule_timeout_interruptible(1);
+}
+
 /*
  * Operations vector for selecting different types of tests.
  */
@@ -192,6 +212,7 @@ struct rcu_torture_ops {
 	int (*completed)(void);
 	void (*deferredfree)(struct rcu_torture *p);
 	void (*sync)(void);
+	void (*cb_barrier)(void);
 	int (*stats)(char *page);
 	char *name;
 };
@@ -265,6 +286,7 @@ static struct rcu_torture_ops rcu_ops = {
 	.completed = rcu_torture_completed,
 	.deferredfree = rcu_torture_deferred_free,
 	.sync = synchronize_rcu,
+	.cb_barrier = rcu_barrier,
 	.stats = NULL,
 	.name = "rcu"
 };
@@ -304,6 +326,7 @@ static struct rcu_torture_ops rcu_sync_ops = {
 	.completed = rcu_torture_completed,
 	.deferredfree = rcu_sync_torture_deferred_free,
 	.sync = synchronize_rcu,
+	.cb_barrier = NULL,
 	.stats = NULL,
 	.name = "rcu_sync"
 };
@@ -364,6 +387,7 @@ static struct rcu_torture_ops rcu_bh_ops = {
 	.completed = rcu_bh_torture_completed,
 	.deferredfree = rcu_bh_torture_deferred_free,
 	.sync = rcu_bh_torture_synchronize,
+	.cb_barrier = rcu_barrier_bh,
 	.stats = NULL,
 	.name = "rcu_bh"
 };
@@ -377,6 +401,7 @@ static struct rcu_torture_ops rcu_bh_sync_ops = {
 	.completed = rcu_bh_torture_completed,
 	.deferredfree = rcu_sync_torture_deferred_free,
 	.sync = rcu_bh_torture_synchronize,
+	.cb_barrier = NULL,
 	.stats = NULL,
 	.name = "rcu_bh_sync"
 };
@@ -458,6 +483,7 @@ static struct rcu_torture_ops srcu_ops = {
 	.completed = srcu_torture_completed,
 	.deferredfree = rcu_sync_torture_deferred_free,
 	.sync = srcu_torture_synchronize,
+	.cb_barrier = NULL,
 	.stats = srcu_torture_stats,
 	.name = "srcu"
 };
@@ -482,6 +508,11 @@ static int sched_torture_completed(void)
 	return 0;
 }
 
+static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu_sched(&p->rtort_rcu, rcu_torture_cb);
+}
+
 static void sched_torture_synchronize(void)
 {
 	synchronize_sched();
@@ -494,12 +525,27 @@ static struct rcu_torture_ops sched_ops = {
 	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
 	.readunlock = sched_torture_read_unlock,
 	.completed = sched_torture_completed,
-	.deferredfree = rcu_sync_torture_deferred_free,
+	.deferredfree = rcu_sched_torture_deferred_free,
 	.sync = sched_torture_synchronize,
+	.cb_barrier = rcu_barrier_sched,
 	.stats = NULL,
 	.name = "sched"
 };
 
+static struct rcu_torture_ops sched_ops_sync = {
+	.init = rcu_sync_torture_init,
+	.cleanup = NULL,
+	.readlock = sched_torture_read_lock,
+	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock = sched_torture_read_unlock,
+	.completed = sched_torture_completed,
+	.deferredfree = rcu_sync_torture_deferred_free,
+	.sync = sched_torture_synchronize,
+	.cb_barrier = NULL,
+	.stats = NULL,
+	.name = "sched_sync"
+};
+
 /*
  * RCU torture writer kthread.  Repeatedly substitutes a new structure
  * for that pointed to by rcu_torture_current, freeing the old structure
@@ -537,6 +583,7 @@ rcu_torture_writer(void *arg)
 		}
 		rcu_torture_current_version++;
 		oldbatch = cur_ops->completed();
+		rcu_stutter_wait();
 	} while (!kthread_should_stop() && !fullstop);
 	VERBOSE_PRINTK_STRING("rcu_torture_writer task stopping");
 	while (!kthread_should_stop())
@@ -560,6 +607,7 @@ rcu_torture_fakewriter(void *arg)
 		schedule_timeout_uninterruptible(1 + rcu_random(&rand)%10);
 		udelay(rcu_random(&rand) & 0x3ff);
 		cur_ops->sync();
+		rcu_stutter_wait();
 	} while (!kthread_should_stop() && !fullstop);
 
 	VERBOSE_PRINTK_STRING("rcu_torture_fakewriter task stopping");
@@ -615,6 +663,7 @@ rcu_torture_reader(void *arg)
 		preempt_enable();
 		cur_ops->readunlock(idx);
 		schedule();
+		rcu_stutter_wait();
 	} while (!kthread_should_stop() && !fullstop);
 	VERBOSE_PRINTK_STRING("rcu_torture_reader task stopping");
 	while (!kthread_should_stop())
@@ -661,6 +710,7 @@ rcu_torture_printk(char *page)
 	if (i > 1) {
 		cnt += sprintf(&page[cnt], "!!! ");
 		atomic_inc(&n_rcu_torture_error);
+		WARN_ON_ONCE(1);
 	}
 	cnt += sprintf(&page[cnt], "Reader Pipe: ");
 	for (i = 0; i < RCU_TORTURE_PIPE_LEN + 1; i++)
@@ -785,15 +835,34 @@ rcu_torture_shuffle(void *arg)
 	return 0;
 }
 
+/* Cause the rcutorture test to "stutter", starting and stopping all
+ * threads periodically.
+ */
+static int
+rcu_torture_stutter(void *arg)
+{
+	VERBOSE_PRINTK_STRING("rcu_torture_stutter task started");
+	do {
+		schedule_timeout_interruptible(stutter * HZ);
+		stutter_pause_test = 1;
+		if (!kthread_should_stop())
+			schedule_timeout_interruptible(stutter * HZ);
+		stutter_pause_test = 0;
+	} while (!kthread_should_stop());
+	VERBOSE_PRINTK_STRING("rcu_torture_stutter task stopping");
+	return 0;
+}
+
 static inline void
 rcu_torture_print_module_parms(char *tag)
 {
 	printk(KERN_ALERT "%s" TORTURE_FLAG
 		"--- %s: nreaders=%d nfakewriters=%d "
 		"stat_interval=%d verbose=%d test_no_idle_hz=%d "
-		"shuffle_interval = %d\n",
+		"shuffle_interval=%d stutter=%d\n",
 		torture_type, tag, nrealreaders, nfakewriters,
-		stat_interval, verbose, test_no_idle_hz, shuffle_interval);
+		stat_interval, verbose, test_no_idle_hz, shuffle_interval,
+		stutter);
 }
 
 static void
@@ -802,6 +871,11 @@ rcu_torture_cleanup(void)
 	int i;
 
 	fullstop = 1;
+	if (stutter_task) {
+		VERBOSE_PRINTK_STRING("Stopping rcu_torture_stutter task");
+		kthread_stop(stutter_task);
+	}
+	stutter_task = NULL;
 	if (shuffler_task) {
 		VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
 		kthread_stop(shuffler_task);
@@ -848,7 +922,9 @@ rcu_torture_cleanup(void)
 	stats_task = NULL;
 
 	/* Wait for all RCU callbacks to fire.  */
-	rcu_barrier();
+
+	if (cur_ops->cb_barrier != NULL)
+		cur_ops->cb_barrier();
 
 	rcu_torture_stats_print();  /* -After- the stats thread is stopped! */
 
@@ -868,7 +944,7 @@ rcu_torture_init(void)
 	int firsterr = 0;
 	static struct rcu_torture_ops *torture_ops[] =
 		{ &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops,
-		  &srcu_ops, &sched_ops, };
+		  &srcu_ops, &sched_ops, &sched_ops_sync, };
 
 	/* Process args and tell the world that the torturer is on the job. */
 	for (i = 0; i < ARRAY_SIZE(torture_ops); i++) {
@@ -988,6 +1064,19 @@ rcu_torture_init(void)
 			goto unwind;
 		}
 	}
+	if (stutter < 0)
+		stutter = 0;
+	if (stutter) {
+		/* Create the stutter thread */
+		stutter_task = kthread_run(rcu_torture_stutter, NULL,
+					  "rcu_torture_stutter");
+		if (IS_ERR(stutter_task)) {
+			firsterr = PTR_ERR(stutter_task);
+			VERBOSE_PRINTK_ERRSTRING("Failed to create stutter");
+			stutter_task = NULL;
+			goto unwind;
+		}
+	}
 	return 0;
 
 unwind: