refperf: Add test for RCU Tasks Trace readers.

This commit adds testing for RCU Tasks Trace readers to the refperf module.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

kernel/rcu/refperf.c

@@ -25,6 +25,7 @@
 #include <linux/notifier.h>
 #include <linux/percpu.h>
 #include <linux/rcupdate.h>
+#include <linux/rcupdate_trace.h>
 #include <linux/reboot.h>
 #include <linux/sched.h>
 #include <linux/spinlock.h>
@@ -157,7 +158,6 @@ static struct ref_perf_ops rcu_ops = {
 	.name		= "rcu"
 };
 
-
 // Definitions for SRCU ref perf testing.
 DEFINE_STATIC_SRCU(srcu_refctl_perf);
 static struct srcu_struct *srcu_ctlp = &srcu_refctl_perf;
@@ -192,6 +192,35 @@ static struct ref_perf_ops srcu_ops = {
 	.name		= "srcu"
 };
 
+// Definitions for RCU Tasks Trace ref perf testing.
+static void rcu_trace_ref_perf_read_section(const int nloops)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		rcu_read_lock_trace();
+		rcu_read_unlock_trace();
+	}
+}
+
+static void rcu_trace_ref_perf_delay_section(const int nloops, const int udl, const int ndl)
+{
+	int i;
+
+	for (i = nloops; i >= 0; i--) {
+		rcu_read_lock_trace();
+		un_delay(udl, ndl);
+		rcu_read_unlock_trace();
+	}
+}
+
+static struct ref_perf_ops rcu_trace_ops = {
+	.init		= rcu_sync_perf_init,
+	.readsection	= rcu_trace_ref_perf_read_section,
+	.delaysection	= rcu_trace_ref_perf_delay_section,
+	.name		= "rcu-trace"
+};
+
 // Definitions for reference count
 static atomic_t refcnt;
 
@@ -584,7 +613,7 @@ ref_perf_init(void)
 	long i;
 	int firsterr = 0;
 	static struct ref_perf_ops *perf_ops[] = {
-		&rcu_ops, &srcu_ops, &refcnt_ops, &rwlock_ops, &rwsem_ops,
+		&rcu_ops, &srcu_ops, &rcu_trace_ops, &refcnt_ops, &rwlock_ops, &rwsem_ops,
 	};
 
 	if (!torture_init_begin(perf_type, verbose))