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>
git-mirror · Apr 25, 2012 · 2fdbb31 · 2fdbb31
1 parent 66f75a5
commit 2fdbb31
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diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
@@ -292,6 +292,7 @@ TRACE_EVENT(rcu_dyntick,
  *	"More callbacks": Still more callbacks, try again to clear them out.
  *	"Callbacks drained": All callbacks processed, off to dyntick idle!
  *	"Timer": Timer fired to cause CPU to continue processing callbacks.
+ *	"Cleanup after idle": Idle exited, timer canceled.
  */
 TRACE_EVENT(rcu_prep_idle,
 

diff --git 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");
 }
 
 /*
-Original file line number
+Diff line change
@@ Expand Up / @@ -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");
     }
     /*
@@ Expand Down @@