[PATCH v2 0/3] tracing: introduce TRACE_EVENT_NOP and use it

[Yafang Shao <laoar.shao@gmail.com>]

In this patchset, I introduce some new macros TRACE_EVENT_NOP,
DEFINE_EVENT_NOP and DECLARE_EVENT_CLASS_NOP, which will
define a tracepoint as do-nothing inline function.
	#define DECLARE_EVENT_NOP(name, proto)			\
		static inline void trace_##name(proto)		\
		{ }						\
		static inline bool trace_##name##_enabled(void)	\
		{						\
			return false;				\
		}

Let's take some examples for why these macros are needed.

- sched
The tracepoints trace_sched_stat_{iowait, blocked, wait, sleep} should
be not exposed to user if CONFIG_SCHEDSTATS is not set.

- rcu
When CONFIG_RCU_TRACE is not set, some rcu tracepoints are defined as
do-nothing macro without validating arguments, that is not proper.
We should validate the arguments.

Yafang Shao (3):
  tracing: introduce TRACE_EVENT_NOP()
  sched/fair: do not expose some tracepoints to user if
    CONFIG_SCHEDSTATS is not set
  rcu: validate arguments for rcu tracepoints

 include/linux/tracepoint.h   | 15 ++++++++
 include/trace/define_trace.h |  8 +++++
 include/trace/events/rcu.h   | 81 ++++++++++++++------------------------------
 include/trace/events/sched.h | 21 ++++++++----
 kernel/rcu/rcu.h             |  9 ++---
 kernel/rcu/tree.c            |  8 ++---
 6 files changed, 68 insertions(+), 74 deletions(-)

-- 
1.8.3.1