#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/notifier.h>
-#include <linux/rcuref.h>
#include <linux/cpu.h>
#include <linux/random.h>
#include <linux/delay.h>
MODULE_LICENSE("GPL");
static int nreaders = -1; /* # reader threads, defaults to 4*ncpus */
-static int stat_interval = 0; /* Interval between stats, in seconds. */
+static int stat_interval; /* Interval between stats, in seconds. */
/* Defaults to "only at end of test". */
-static int verbose = 0; /* Print more debug info. */
+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)*/
MODULE_PARM(nreaders, "i");
MODULE_PARM_DESC(nreaders, "Number of RCU reader threads");
MODULE_PARM_DESC(stat_interval, "Number of seconds between stats printk()s");
MODULE_PARM(verbose, "i");
MODULE_PARM_DESC(verbose, "Enable verbose debugging printk()s");
+MODULE_PARM(test_no_idle_hz, "i");
+MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
+MODULE_PARM(shuffle_interval, "i");
+MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
#define TORTURE_FLAG "rcutorture: "
#define PRINTK_STRING(s) \
do { printk(KERN_ALERT TORTURE_FLAG s "\n"); } while (0)
static struct task_struct *writer_task;
static struct task_struct **reader_tasks;
static struct task_struct *stats_task;
+static struct task_struct *shuffler_task;
#define RCU_TORTURE_PIPE_LEN 10
/*
* Allocate an element from the rcu_tortures pool.
*/
-struct rcu_torture *
+static struct rcu_torture *
rcu_torture_alloc(void)
{
struct list_head *p;
- spin_lock(&rcu_torture_lock);
+ spin_lock_bh(&rcu_torture_lock);
if (list_empty(&rcu_torture_freelist)) {
atomic_inc(&n_rcu_torture_alloc_fail);
- spin_unlock(&rcu_torture_lock);
+ spin_unlock_bh(&rcu_torture_lock);
return NULL;
}
atomic_inc(&n_rcu_torture_alloc);
p = rcu_torture_freelist.next;
list_del_init(p);
- spin_unlock(&rcu_torture_lock);
+ spin_unlock_bh(&rcu_torture_lock);
return container_of(p, struct rcu_torture, rtort_free);
}
rcu_torture_free(struct rcu_torture *p)
{
atomic_inc(&n_rcu_torture_free);
- spin_lock(&rcu_torture_lock);
+ spin_lock_bh(&rcu_torture_lock);
list_add_tail(&p->rtort_free, &rcu_torture_freelist);
- spin_unlock(&rcu_torture_lock);
+ spin_unlock_bh(&rcu_torture_lock);
}
static void
return 0;
}
+static int rcu_idle_cpu; /* Force all torture tasks off this CPU */
+
+/* Shuffle tasks such that we allow @rcu_idle_cpu to become idle. A special case
+ * is when @rcu_idle_cpu = -1, when we allow the tasks to run on all CPUs.
+ */
+void rcu_torture_shuffle_tasks(void)
+{
+ cpumask_t tmp_mask = CPU_MASK_ALL;
+ int i;
+
+ lock_cpu_hotplug();
+
+ /* No point in shuffling if there is only one online CPU (ex: UP) */
+ if (num_online_cpus() == 1) {
+ unlock_cpu_hotplug();
+ return;
+ }
+
+ if (rcu_idle_cpu != -1)
+ cpu_clear(rcu_idle_cpu, tmp_mask);
+
+ set_cpus_allowed(current, tmp_mask);
+
+ if (reader_tasks != NULL) {
+ for (i = 0; i < nrealreaders; i++)
+ if (reader_tasks[i])
+ set_cpus_allowed(reader_tasks[i], tmp_mask);
+ }
+
+ if (writer_task)
+ set_cpus_allowed(writer_task, tmp_mask);
+
+ if (stats_task)
+ set_cpus_allowed(stats_task, tmp_mask);
+
+ if (rcu_idle_cpu == -1)
+ rcu_idle_cpu = num_online_cpus() - 1;
+ else
+ rcu_idle_cpu--;
+
+ unlock_cpu_hotplug();
+}
+
+/* Shuffle tasks across CPUs, with the intent of allowing each CPU in the
+ * system to become idle at a time and cut off its timer ticks. This is meant
+ * to test the support for such tickless idle CPU in RCU.
+ */
+static int
+rcu_torture_shuffle(void *arg)
+{
+ VERBOSE_PRINTK_STRING("rcu_torture_shuffle task started");
+ do {
+ schedule_timeout_interruptible(shuffle_interval * HZ);
+ rcu_torture_shuffle_tasks();
+ } while (!kthread_should_stop());
+ VERBOSE_PRINTK_STRING("rcu_torture_shuffle task stopping");
+ return 0;
+}
+
static void
rcu_torture_cleanup(void)
{
int i;
fullstop = 1;
+ if (shuffler_task != NULL) {
+ VERBOSE_PRINTK_STRING("Stopping rcu_torture_shuffle task");
+ kthread_stop(shuffler_task);
+ }
+ shuffler_task = NULL;
+
if (writer_task != NULL) {
VERBOSE_PRINTK_STRING("Stopping rcu_torture_writer task");
kthread_stop(writer_task);
stats_task = NULL;
/* Wait for all RCU callbacks to fire. */
+ rcu_barrier();
- for (i = 0; i < RCU_TORTURE_PIPE_LEN; i++)
- synchronize_rcu();
rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
printk(KERN_ALERT TORTURE_FLAG
"--- End of test: %s\n",
nrealreaders = nreaders;
else
nrealreaders = 2 * num_online_cpus();
- printk(KERN_ALERT TORTURE_FLAG
- "--- Start of test: nreaders=%d stat_interval=%d verbose=%d\n",
- nrealreaders, stat_interval, verbose);
+ printk(KERN_ALERT TORTURE_FLAG "--- Start of test: nreaders=%d "
+ "stat_interval=%d verbose=%d test_no_idle_hz=%d "
+ "shuffle_interval = %d\n",
+ nrealreaders, stat_interval, verbose, test_no_idle_hz,
+ shuffle_interval);
fullstop = 0;
/* Set up the freelist. */
goto unwind;
}
}
+ if (test_no_idle_hz) {
+ rcu_idle_cpu = num_online_cpus() - 1;
+ /* Create the shuffler thread */
+ shuffler_task = kthread_run(rcu_torture_shuffle, NULL,
+ "rcu_torture_shuffle");
+ if (IS_ERR(shuffler_task)) {
+ firsterr = PTR_ERR(shuffler_task);
+ VERBOSE_PRINTK_ERRSTRING("Failed to create shuffler");
+ shuffler_task = NULL;
+ goto unwind;
+ }
+ }
return 0;
unwind:
projects / linux-2.6-omap-h63xx.git / blobdiff