* Authors: Paul E. McKenney <paulmck@linux.ibm.com>
* Josh Triplett <josh@joshtriplett.org>
*
- * See also: Documentation/RCU/torture.txt
+ * See also: Documentation/RCU/torture.rst
*/
#define pr_fmt(fmt) fmt
torture_param(int, onoff_holdoff, 0, "Time after boot before CPU hotplugs (s)");
torture_param(int, onoff_interval, 0,
"Time between CPU hotplugs (jiffies), 0=disable");
+torture_param(int, read_exit_delay, 13,
+ "Delay between read-then-exit episodes (s)");
+torture_param(int, read_exit_burst, 16,
+ "# of read-then-exit bursts per episode, zero to disable");
torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
static struct task_struct *fwd_prog_task;
static struct task_struct **barrier_cbs_tasks;
static struct task_struct *barrier_task;
+static struct task_struct *read_exit_task;
#define RCU_TORTURE_PIPE_LEN 10
static atomic_long_t n_rcu_torture_timers;
static long n_barrier_attempts;
static long n_barrier_successes; /* did rcu_barrier test succeed? */
+static unsigned long n_read_exits;
static struct list_head rcu_torture_removed;
static unsigned long shutdown_jiffies;
WARN(1, "%s: rtort_pipe_count: %d\n", __func__, rcu_tortures[i].rtort_pipe_count);
}
} while (!torture_must_stop());
+ rcu_torture_current = NULL; // Let stats task know that we are done.
/* Reset expediting back to unexpedited. */
if (expediting > 0)
expediting = -expediting;
struct rt_read_seg *rtrsp1;
unsigned long long ts;
+ WARN_ON_ONCE(!rcu_is_watching());
newstate = rcutorture_extend_mask(readstate, trsp);
rcutorture_one_extend(&readstate, newstate, trsp, rtrsp++);
started = cur_ops->get_gp_seq();
n_rcu_torture_boosts,
atomic_long_read(&n_rcu_torture_timers));
torture_onoff_stats();
- pr_cont("barrier: %ld/%ld:%ld\n",
+ pr_cont("barrier: %ld/%ld:%ld ",
data_race(n_barrier_successes),
data_race(n_barrier_attempts),
data_race(n_rcu_torture_barrier_error));
+ pr_cont("read-exits: %ld\n", data_race(n_read_exits));
pr_alert("%s%s ", torture_type, TORTURE_FLAG);
if (atomic_read(&n_rcu_torture_mberror) ||
"stall_cpu=%d stall_cpu_holdoff=%d stall_cpu_irqsoff=%d "
"stall_cpu_block=%d "
"n_barrier_cbs=%d "
- "onoff_interval=%d onoff_holdoff=%d\n",
+ "onoff_interval=%d onoff_holdoff=%d "
+ "read_exit_delay=%d read_exit_burst=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
stat_interval, verbose, test_no_idle_hz, shuffle_interval,
stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
stall_cpu, stall_cpu_holdoff, stall_cpu_irqsoff,
stall_cpu_block,
n_barrier_cbs,
- onoff_interval, onoff_holdoff);
+ onoff_interval, onoff_holdoff,
+ read_exit_delay, read_exit_burst);
}
static int rcutorture_booster_cleanup(unsigned int cpu)
static int rcu_torture_barrier_cbs(void *arg)
{
long myid = (long)arg;
- bool lastphase = 0;
+ bool lastphase = false;
bool newphase;
struct rcu_head rcu;
return true;
}
+static bool read_exit_child_stop;
+static bool read_exit_child_stopped;
+static wait_queue_head_t read_exit_wq;
+
+// Child kthread which just does an rcutorture reader and exits.
+static int rcu_torture_read_exit_child(void *trsp_in)
+{
+ struct torture_random_state *trsp = trsp_in;
+
+ set_user_nice(current, MAX_NICE);
+ // Minimize time between reading and exiting.
+ while (!kthread_should_stop())
+ schedule_timeout_uninterruptible(1);
+ (void)rcu_torture_one_read(trsp);
+ return 0;
+}
+
+// Parent kthread which creates and destroys read-exit child kthreads.
+static int rcu_torture_read_exit(void *unused)
+{
+ int count = 0;
+ bool errexit = false;
+ int i;
+ struct task_struct *tsp;
+ DEFINE_TORTURE_RANDOM(trs);
+
+ // Allocate and initialize.
+ set_user_nice(current, MAX_NICE);
+ VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of test");
+
+ // Each pass through this loop does one read-exit episode.
+ do {
+ if (++count > read_exit_burst) {
+ VERBOSE_TOROUT_STRING("rcu_torture_read_exit: End of episode");
+ rcu_barrier(); // Wait for task_struct free, avoid OOM.
+ for (i = 0; i < read_exit_delay; i++) {
+ schedule_timeout_uninterruptible(HZ);
+ if (READ_ONCE(read_exit_child_stop))
+ break;
+ }
+ if (!READ_ONCE(read_exit_child_stop))
+ VERBOSE_TOROUT_STRING("rcu_torture_read_exit: Start of episode");
+ count = 0;
+ }
+ if (READ_ONCE(read_exit_child_stop))
+ break;
+ // Spawn child.
+ tsp = kthread_run(rcu_torture_read_exit_child,
+ &trs, "%s",
+ "rcu_torture_read_exit_child");
+ if (IS_ERR(tsp)) {
+ VERBOSE_TOROUT_ERRSTRING("out of memory");
+ errexit = true;
+ tsp = NULL;
+ break;
+ }
+ cond_resched();
+ kthread_stop(tsp);
+ n_read_exits ++;
+ stutter_wait("rcu_torture_read_exit");
+ } while (!errexit && !READ_ONCE(read_exit_child_stop));
+
+ // Clean up and exit.
+ smp_store_release(&read_exit_child_stopped, true); // After reaping.
+ smp_mb(); // Store before wakeup.
+ wake_up(&read_exit_wq);
+ while (!torture_must_stop())
+ schedule_timeout_uninterruptible(1);
+ torture_kthread_stopping("rcu_torture_read_exit");
+ return 0;
+}
+
+static int rcu_torture_read_exit_init(void)
+{
+ if (read_exit_burst <= 0)
+ return -EINVAL;
+ init_waitqueue_head(&read_exit_wq);
+ read_exit_child_stop = false;
+ read_exit_child_stopped = false;
+ return torture_create_kthread(rcu_torture_read_exit, NULL,
+ read_exit_task);
+}
+
+static void rcu_torture_read_exit_cleanup(void)
+{
+ if (!read_exit_task)
+ return;
+ WRITE_ONCE(read_exit_child_stop, true);
+ smp_mb(); // Above write before wait.
+ wait_event(read_exit_wq, smp_load_acquire(&read_exit_child_stopped));
+ torture_stop_kthread(rcutorture_read_exit, read_exit_task);
+}
+
static enum cpuhp_state rcutor_hp;
static void
}
show_rcu_gp_kthreads();
+ rcu_torture_read_exit_cleanup();
rcu_torture_barrier_cleanup();
torture_stop_kthread(rcu_torture_fwd_prog, fwd_prog_task);
torture_stop_kthread(rcu_torture_stall, stall_task);
reader_tasks[i]);
kfree(reader_tasks);
}
- rcu_torture_current = NULL;
if (fakewriter_tasks) {
for (i = 0; i < nfakewriters; i++) {
if (firsterr)
goto unwind;
firsterr = rcu_torture_barrier_init();
+ if (firsterr)
+ goto unwind;
+ firsterr = rcu_torture_read_exit_init();
if (firsterr)
goto unwind;
if (object_debug)
projects / linux-2.6-microblaze.git / blobdiff