rcu: Add RCU_FAST_NO_HZ tracing for idle exit

Traces of rcu_prep_idle events can be confusing because
rcu_cleanup_after_idle() does no tracing.  This commit therefore adds
this tracing.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index c023464816be..1e561ab952a3 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -2085,6 +2085,7 @@ static void rcu_prepare_for_idle_init(int cpu)
 static void rcu_cleanup_after_idle(int cpu)
 {
         hrtimer_cancel(&per_cpu(rcu_idle_gp_timer, cpu));
+        trace_rcu_prep_idle("Cleanup after idle");
 }
 
 /*