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-rw-r--r--Documentation/RCU/torture.txt8
-rw-r--r--kernel/rcutorture.c59
2 files changed, 63 insertions, 4 deletions
diff --git a/Documentation/RCU/torture.txt b/Documentation/RCU/torture.txt
index 2967a65269d8..02b3d14c0209 100644
--- a/Documentation/RCU/torture.txt
+++ b/Documentation/RCU/torture.txt
@@ -46,9 +46,15 @@ stat_interval The number of seconds between output of torture
shuffle_interval
The number of seconds to keep the test threads affinitied
- to a particular subset of the CPUs, defaults to 5 seconds.
+ to a particular subset of the CPUs, defaults to 3 seconds.
Used in conjunction with test_no_idle_hz.
+stutter The length of time to run the test before pausing for this
+ same period of time. Defaults to "stutter=5", so as
+ to run and pause for (roughly) five-second intervals.
+ Specifying "stutter=0" causes the test to run continuously
+ without pausing, which is the old default behavior.
+
test_no_idle_hz Whether or not to test the ability of RCU to operate in
a kernel that disables the scheduling-clock interrupt to
idle CPUs. Boolean parameter, "1" to test, "0" otherwise.
diff --git a/kernel/rcutorture.c b/kernel/rcutorture.c
index 0ca7e9b290b0..98ae7d168225 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 +123,8 @@ 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;
+
/*
* Allocate an element from the rcu_tortures pool.
*/
@@ -179,6 +185,13 @@ rcu_random(struct rcu_random_state *rrsp)
return swahw32(rrsp->rrs_state);
}
+static void
+rcu_stutter_wait(void)
+{
+ while (stutter_pause_test)
+ schedule_timeout_interruptible(1);
+}
+
/*
* Operations vector for selecting different types of tests.
*/
@@ -563,6 +576,7 @@ 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())
@@ -586,6 +600,7 @@ 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");
@@ -641,6 +656,7 @@ 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())
@@ -812,15 +828,34 @@ 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
@@ -829,6 +864,11 @@ 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);
@@ -1017,6 +1057,19 @@ 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: