[PATCH] tracing, rcu: Hide trace event rcu_nocb_wake when not used

[Steven Rostedt]

From: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>

The trace event rcu_nocb_wake is only used when CONFIG_RCU_NOCB_CPU is
defined. But the trace event is defined regardless. As defined trace
events take up memory, it is a waste to have it defined when not used.
Surround the trace event with an #ifdef to have it only defined when it
is used.

Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
---
Index: linux-trace.git/include/trace/events/rcu.h
===================================================================
--- linux-trace.git.orig/include/trace/events/rcu.h
+++ linux-trace.git/include/trace/events/rcu.h
@@ -242,6 +242,7 @@ TRACE_EVENT(rcu_exp_funnel_lock,
 		  __entry->grphi, __entry->gpevent)
 );
 
+#ifdef CONFIG_RCU_NOCB_CPU
 /*
  * Tracepoint for RCU no-CBs CPU callback handoffs.  This event is intended
  * to assist debugging of these handoffs.
@@ -284,6 +285,7 @@ TRACE_EVENT(rcu_nocb_wake,
 
 	TP_printk("%s %d %s", __entry->rcuname, __entry->cpu, __entry->reason)
 );
+#endif
 
 /*
  * Tracepoint for tasks blocking within preemptible-RCU read-side