[PATCH tip/core/rcu 4/6] tracing, rcu: Hide trace event rcu_nocb_wake when not used

From: Paul E. McKenney
Date: Fri Dec 01 2017 - 14:43:16 EST


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>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/trace/events/rcu.h | 2 ++
1 file changed, 2 insertions(+)

diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 59d40c454aa0..dbca79ea0677 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -243,6 +243,7 @@ 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.
@@ -285,6 +286,7 @@ 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
--
2.5.2