tracing/rcu: Add trace_##name##__rcuidle() static tracepoint for inside rcu_idle_exit() sections (2fbb90db) · Commits · 戴 / test

Added is a new static inline function that lets *any* tracepoint be used inside a rcu_idle_exit() section. And this also solves the problem where the same tracepoint may be used inside a rcu_idle_exit() section as well as outside of one. I added a new tracepoint function with a "_rcuidle" extension. All tracepoints can be used with either the normal "trace_foobar()" function, or the "trace_foobar_rcuidle()" function when inside a rcu_idle_exit() section. All tracepoints defined by TRACE_EVENT() or any of the derivatives will have a "_rcuidle()" function also defined. When a tracepoint is used within an rcu_idle_exit() section, the "_rcuidle()" version must be used. This denotes that the tracepoint is within rcu_idle_exit() and it allows the rcu read locks within the tracepoint to still be valid, as this version takes us out of rcu_idle_exit(). Another nice aspect about this patch is that "static inline"s are not compiled into text when not used. So only the tracepoints that actually use the _rcuidle() version will have them defined in the actual text that is booted. Link: http://lkml.kernel.org/r/1328563113.2200.39.camel@gandalf.stny.rr.com > Acked-by:

Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:

Josh Triplett <josh@joshtriplett.org> Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

include/linux/tracepoint.h

+18 −4

Original line number	Diff line number	Diff line
		@@ -114,7 +114,7 @@ static inline void tracepoint_synchronize_unregister(void)
		* as "(void *, void)". The DECLARE_TRACE_NOARGS() will pass in just
		* "void data", where as the DECLARE_TRACE() will pass in "void data, proto".
		*/
		#define __DO_TRACE(tp, proto, args, cond) \
		#define __DO_TRACE(tp, proto, args, cond, prercu, postrcu) \
		do { \
		struct tracepoint_func *it_func_ptr; \
		void *it_func; \
		@@ -122,6 +122,7 @@ static inline void tracepoint_synchronize_unregister(void)
		\
		if (!(cond)) \
		return; \
		prercu; \
		rcu_read_lock_sched_notrace(); \
		it_func_ptr = rcu_dereference_sched((tp)->funcs); \
		if (it_func_ptr) { \
		@@ -132,6 +133,7 @@ static inline void tracepoint_synchronize_unregister(void)
		} while ((++it_func_ptr)->func); \
		} \
		rcu_read_unlock_sched_notrace(); \
		postrcu; \
		} while (0)

		/*
		@@ -147,7 +149,17 @@ static inline void tracepoint_synchronize_unregister(void)
		__DO_TRACE(&__tracepoint_##name, \
		TP_PROTO(data_proto), \
		TP_ARGS(data_args), \
		TP_CONDITION(cond)); \
		TP_CONDITION(cond),,); \
		} \
		static inline void trace_##name##_rcuidle(proto) \
		{ \
		if (static_branch(&__tracepoint_##name.key)) \
		__DO_TRACE(&__tracepoint_##name, \
		TP_PROTO(data_proto), \
		TP_ARGS(data_args), \
		TP_CONDITION(cond), \
		rcu_idle_exit(), \
		rcu_idle_enter()); \
		} \
		static inline int \
		register_trace_##name(void (probe)(data_proto), void data) \
		@@ -193,6 +205,8 @@ static inline void tracepoint_synchronize_unregister(void)
		#define __DECLARE_TRACE(name, proto, args, cond, data_proto, data_args) \
		static inline void trace_##name(proto) \
		{ } \
		static inline void trace_##name##_rcuidle(proto) \
		{ } \
		static inline int \
		register_trace_##name(void (*probe)(data_proto), \
		void *data) \

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