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_stutter = 3; /* Wait time between bursts (s). */
static char *torture_type = "rcu"; /* What RCU implementation to torture. */
module_param(nreaders, int, 0444);
MODULE_PARM_DESC(stutter, "Number of seconds to run/halt test");
module_param(irqreader, int, 0444);
MODULE_PARM_DESC(irqreader, "Allow RCU readers from irq handlers");
+module_param(fqs_duration, int, 0444);
+MODULE_PARM_DESC(fqs_duration, "Duration of fqs bursts (us)");
+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(torture_type, charp, 0444);
MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh, srcu)");
static struct task_struct *stats_task;
static struct task_struct *shuffler_task;
static struct task_struct *stutter_task;
+static struct task_struct *fqs_task;
#define RCU_TORTURE_PIPE_LEN 10
void (*deferred_free)(struct rcu_torture *p);
void (*sync)(void);
void (*cb_barrier)(void);
+ void (*fqs)(void);
int (*stats)(char *page);
int irq_capable;
char *name;
.deferred_free = rcu_torture_deferred_free,
.sync = synchronize_rcu,
.cb_barrier = rcu_barrier,
+ .fqs = rcu_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "rcu"
.deferred_free = rcu_sync_torture_deferred_free,
.sync = synchronize_rcu,
.cb_barrier = NULL,
+ .fqs = rcu_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "rcu_sync"
.deferred_free = rcu_sync_torture_deferred_free,
.sync = synchronize_rcu_expedited,
.cb_barrier = NULL,
+ .fqs = rcu_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "rcu_expedited"
{
struct rcu_bh_torture_synchronize rcu;
+ init_rcu_head_on_stack(&rcu.head);
init_completion(&rcu.completion);
call_rcu_bh(&rcu.head, rcu_bh_torture_wakeme_after_cb);
wait_for_completion(&rcu.completion);
+ destroy_rcu_head_on_stack(&rcu.head);
}
static struct rcu_torture_ops rcu_bh_ops = {
.deferred_free = rcu_bh_torture_deferred_free,
.sync = rcu_bh_torture_synchronize,
.cb_barrier = rcu_barrier_bh,
+ .fqs = rcu_bh_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "rcu_bh"
.deferred_free = rcu_sync_torture_deferred_free,
.sync = rcu_bh_torture_synchronize,
.cb_barrier = NULL,
+ .fqs = rcu_bh_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "rcu_bh_sync"
.deferred_free = rcu_sched_torture_deferred_free,
.sync = sched_torture_synchronize,
.cb_barrier = rcu_barrier_sched,
+ .fqs = rcu_sched_force_quiescent_state,
.stats = NULL,
.irq_capable = 1,
.name = "sched"
.deferred_free = rcu_sync_torture_deferred_free,
.sync = sched_torture_synchronize,
.cb_barrier = NULL,
+ .fqs = rcu_sched_force_quiescent_state,
.stats = NULL,
.name = "sched_sync"
};
.deferred_free = rcu_sync_torture_deferred_free,
.sync = synchronize_sched_expedited,
.cb_barrier = NULL,
- .stats = rcu_expedited_torture_stats,
+ .fqs = rcu_sched_force_quiescent_state,
+ .stats = NULL,
.irq_capable = 1,
.name = "sched_expedited"
};
/*
+ * RCU torture force-quiescent-state kthread. Repeatedly induces
+ * bursts of calls to force_quiescent_state(), increasing the probability
+ * of occurrence of some important types of race conditions.
+ */
+static int
+rcu_torture_fqs(void *arg)
+{
+ unsigned long fqs_resume_time;
+ int fqs_burst_remaining;
+
+ VERBOSE_PRINTK_STRING("rcu_torture_fqs task started");
+ do {
+ fqs_resume_time = jiffies + fqs_stutter * HZ;
+ while (jiffies - fqs_resume_time > LONG_MAX) {
+ schedule_timeout_interruptible(1);
+ }
+ fqs_burst_remaining = fqs_duration;
+ while (fqs_burst_remaining > 0) {
+ cur_ops->fqs();
+ udelay(fqs_holdoff);
+ fqs_burst_remaining -= fqs_holdoff;
+ }
+ rcu_stutter_wait("rcu_torture_fqs");
+ } while (!kthread_should_stop() && fullstop == FULLSTOP_DONTSTOP);
+ VERBOSE_PRINTK_STRING("rcu_torture_fqs task stopping");
+ rcutorture_shutdown_absorb("rcu_torture_fqs");
+ while (!kthread_should_stop())
+ schedule_timeout_uninterruptible(1);
+ return 0;
+}
+
+/*
* RCU torture writer kthread. Repeatedly substitutes a new structure
* for that pointed to by rcu_torture_current, freeing the old structure
* after a series of grace periods (the "pipeline").
idx = cur_ops->readlock();
completed = cur_ops->completed();
- p = rcu_dereference(rcu_torture_current);
+ p = rcu_dereference_check(rcu_torture_current,
+ rcu_read_lock_held() ||
+ rcu_read_lock_bh_held() ||
+ rcu_read_lock_sched_held() ||
+ srcu_read_lock_held(&srcu_ctl));
if (p == NULL) {
/* Leave because rcu_torture_writer is not yet underway */
cur_ops->readunlock(idx);
do {
if (irqreader && cur_ops->irq_capable) {
if (!timer_pending(&t))
- mod_timer(&t, 1);
+ mod_timer(&t, jiffies + 1);
}
idx = cur_ops->readlock();
completed = cur_ops->completed();
- p = rcu_dereference(rcu_torture_current);
+ p = rcu_dereference_check(rcu_torture_current,
+ rcu_read_lock_held() ||
+ rcu_read_lock_bh_held() ||
+ rcu_read_lock_sched_held() ||
+ srcu_read_lock_held(&srcu_ctl));
if (p == NULL) {
/* Wait for rcu_torture_writer to get underway */
cur_ops->readunlock(idx);
printk(KERN_ALERT "%s" TORTURE_FLAG
"--- %s: nreaders=%d nfakewriters=%d "
"stat_interval=%d verbose=%d test_no_idle_hz=%d "
- "shuffle_interval=%d stutter=%d irqreader=%d\n",
+ "shuffle_interval=%d stutter=%d irqreader=%d "
+ "fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
stat_interval, verbose, test_no_idle_hz, shuffle_interval,
- stutter, irqreader);
+ stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter);
}
static struct notifier_block rcutorture_nb = {
}
stats_task = NULL;
+ if (fqs_task) {
+ VERBOSE_PRINTK_STRING("Stopping rcu_torture_fqs task");
+ kthread_stop(fqs_task);
+ }
+ fqs_task = NULL;
+
/* Wait for all RCU callbacks to fire. */
if (cur_ops->cb_barrier != NULL)
mutex_unlock(&fullstop_mutex);
return -EINVAL;
}
+ if (cur_ops->fqs == NULL && fqs_duration != 0) {
+ printk(KERN_ALERT "rcu-torture: ->fqs NULL and non-zero "
+ "fqs_duration, fqs disabled.\n");
+ fqs_duration = 0;
+ }
if (cur_ops->init)
cur_ops->init(); /* no "goto unwind" prior to this point!!! */
goto unwind;
}
}
+ if (fqs_duration < 0)
+ fqs_duration = 0;
+ if (fqs_duration) {
+ /* Create the stutter thread */
+ fqs_task = kthread_run(rcu_torture_fqs, NULL,
+ "rcu_torture_fqs");
+ if (IS_ERR(fqs_task)) {
+ firsterr = PTR_ERR(fqs_task);
+ VERBOSE_PRINTK_ERRSTRING("Failed to create fqs");
+ fqs_task = NULL;
+ goto unwind;
+ }
+ }
register_reboot_notifier(&rcutorture_nb);
mutex_unlock(&fullstop_mutex);
return 0;
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff