refperf: Add test for RCU Tasks readers

This commit adds testing for RCU Tasks readers to the refperf module.
This also applies to RCU Rude readers, as both flavors have empty
(as in non-existent) read-side markers.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

kernel/rcu/refperf.c

@@ -192,6 +192,31 @@ static struct ref_perf_ops srcu_ops = {
 	.name		= "srcu"
 };
 
+// Definitions for RCU Tasks ref perf testing: Empty read markers.
+// These definitions also work for RCU Rude readers.
+static void rcu_tasks_ref_perf_read_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--)
+		continue;
+}
+
+static void rcu_tasks_ref_perf_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--)
+		un_delay(udl, ndl);
+}
+
+static struct ref_perf_ops rcu_tasks_ops = {
+	.init		= rcu_sync_perf_init,
+	.readsection	= rcu_tasks_ref_perf_read_section,
+	.delaysection	= rcu_tasks_ref_perf_delay_section,
+	.name		= "rcu-tasks"
+};
+
 // Definitions for RCU Tasks Trace ref perf testing.
 static void rcu_trace_ref_perf_read_section(const int nloops)
 {
@@ -613,7 +638,8 @@ ref_perf_init(void)
 	long i;
 	int firsterr = 0;
 	static struct ref_perf_ops *perf_ops[] = {
-		&rcu_ops, &srcu_ops, &rcu_trace_ops, &refcnt_ops, &rwlock_ops, &rwsem_ops,
+		&rcu_ops, &srcu_ops, &rcu_trace_ops, &rcu_tasks_ops,
+		&refcnt_ops, &rwlock_ops, &rwsem_ops,
 	};
 
 	if (!torture_init_begin(perf_type, verbose))