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Tracepoint: introduce tracepoint() API

PATCH In review Mathieu Desnoyers 2 participants 2 messages Nov 25, 2011 Tracing

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Mathieu Desnoyers

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#0 lore raw

PATCH 1/1 Tracepoint: introduce tracepoint() API

Introduce:

tracepoint(event_name, arg1, arg2, ...)

while keeping the old tracepoint API in place, e.g.:

trace_event_name(arg1, arg2, ...)

This allows skipping parameter side-effects (pointer dereference, function calls, ...) when the tracepoint is not dynamically activated.

This allows progressive (and partial) API transition from trace_*(...) to tracepoint(*, ...). This differs from the previous attempt to introduce this change by Jason Baron in that it supports both the original and new tracepoint APIs, which makes the transition smoother than having to change all instrumentation at once.

Signed-off-by Mathieu Desnoyers <[email protected]>
Acked-by Steven Rostedt <[email protected]>
Acked-by Jason Baron <[email protected]>
Link https://lkml.org/lkml/2009/5/19/328
CC Eric Dumazet <[email protected]>
CC Peter Zijlstra <[email protected]>
CC Ingo Molnar <[email protected]>
CC Christoph Lameter <[email protected]>

---

include/linux/tracepoint.h +19 -4
index d530a44..c9c73f7 100644
@@ -107,6 +107,12 @@ void tracepoint_update_probe_range(struct tracepoint * const *begin,
 
 #ifdef CONFIG_TRACEPOINTS
 
+#define tracepoint(name, args...)					\
+	do {								\
+		if (static_branch(&__tracepoint_##name.key))		\
+			__trace_##name(args);				\
+	} while (0)
+
 /*
  * it_func[0] is never NULL because there is at least one element in the array
  * when the array itself is non NULL.

@@ -144,13 +150,17 @@ void tracepoint_update_probe_range(struct tracepoint * const *begin,
  */
 #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args)	\
 	extern struct tracepoint __tracepoint_##name;			\
+	static inline void __trace_##name(proto)			\
+	{								\
+		__DO_TRACE(&__tracepoint_##name,			\
+			TP_PROTO(data_proto),				\
+			TP_ARGS(data_args),				\
+			TP_CONDITION(cond));				\
+	}								\
 	static inline void trace_##name(proto)				\
 	{								\
 		if (static_branch(&__tracepoint_##name.key))		\
-			__DO_TRACE(&__tracepoint_##name,		\
-				TP_PROTO(data_proto),			\
-				TP_ARGS(data_args),			\
-				TP_CONDITION(cond));			\
+			__trace_##name(args);				\
 	}								\
 	static inline int						\
 	register_trace_##name(void (*probe)(data_proto), void *data)	\

@@ -193,7 +203,12 @@ void tracepoint_update_probe_range(struct tracepoint * const *begin,
 	EXPORT_SYMBOL(__tracepoint_##name)
 
 #else /* !CONFIG_TRACEPOINTS */
+
+#define tracepoint(name, args...)	__trace_##name(args)
+
 #define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args)	\
+	static inline void __trace_##name(proto)			\
+	{ }								\
 	static inline void trace_##name(proto)				\
 	{ }								\
 	static inline int						\
Signature · 4 lines
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com
Acked-by on v1 1/1
#1 lore raw
Quoted 25 lines · Mathieu Desnoyers

Introduce:

tracepoint(event_name, arg1, arg2, ...)

while keeping the old tracepoint API in place, e.g.:

trace_event_name(arg1, arg2, ...)

This allows skipping parameter side-effects (pointer dereference, function calls, ...) when the tracepoint is not dynamically activated.

This allows progressive (and partial) API transition from trace_*(...) to tracepoint(*, ...). This differs from the previous attempt to introduce this change by Jason Baron in that it supports both the original and new tracepoint APIs, which makes the transition smoother than having to change all instrumentation at once.

Signed-off-by Mathieu Desnoyers <[email protected]>
Acked-by Steven Rostedt <[email protected]>
Acked-by Jason Baron <[email protected]>
Link https://lkml.org/lkml/2009/5/19/328
CC Eric Dumazet <[email protected]>
CC Peter Zijlstra <[email protected]>
CC Ingo Molnar <[email protected]>
CC Christoph Lameter <[email protected]>
Quoted 1 line

---

Seems good to me, thanks Mathieu !

Acked-by Eric Dumazet <[email protected]>