Re: No definition of trace_sched_stat_wait in kernel found!

[Li Zefan <lizf@cn.fujitsu.com>]

Jack Daniel wrote:
> Greetings,
> 
> With reference to the function update_stats_wait_end(), there seems to
> be a call to trace_sched_stat_wait(). But strangely I can find no
> definition of this function even though the kernel compiles without
> any errors. There is no reference to this function
> trace_sched_stat_wait() in the System.map file either, which means
> this is not getting compiled? Could someone please make sense of this
> absurdity.
> 

It's generated in include/trace/events/sched.h:

DEFINE_EVENT(sched_stat_template, sched_stat_wait,
             TP_PROTO(struct task_struct *tsk, u64 delay),
             TP_ARGS(tsk, delay));


And the trace_xxx() function is defined by macros in include/linux/tracepoint.h:

#define __DECLARE_TRACE(name, proto, args, data_proto, data_args)       \
        extern struct tracepoint __tracepoint_##name;                   \
        static inline void trace_##name(proto)                          \
        {                                                               \
                if (unlikely(__tracepoint_##name.state))                \
                        __DO_TRACE(&__tracepoint_##name,                \
                                TP_PROTO(data_proto),                   \
                                TP_ARGS(data_args));                    \
        }
	...