Re: [PATCH 2/8] tracing: create automated trace defines

[Mathieu Desnoyers]

* Jeremy Fitzhardinge (jeremy@xxxxxxxx) wrote:
> Mathieu Desnoyers wrote:
>> * Jeremy Fitzhardinge (jeremy@xxxxxxxx) wrote:
>>> -#define __DO_TRACE(tp, proto, args)					\
>>> -	do {								\
>>> +#define DEFINE_DO_TRACE(name, proto, args)				\
>>> +	void __do_trace_##name(struct tracepoint *tp, TP_PROTO(proto))	\
>>>     
>>
>> I fear that won't work with "void" prototype. If we need this kind of
>> flexibility, we will need to create a special case for empty prototype.
>>   
>
> Yes, that has been a bit awkward.  I couldn't find a way to create a  
> no-param tracepoint, and so ended up passing a dummy arg.  Stupid C 
> syntax.
>
> On the other hand, I can get something that actually compiles this way...
>
>    J

Is your only problem the fact that tracepoints include rcupdate.h ? This
can easily be solved by moving rcu_read_(un)lock_sched_notrace to a
rcu-update-<insert meaningful name here> and include this header in
rcupdate.h and tracepoint.h.

We could keep the indirection layer you proposed for synchronize_sched()
though, even if it adds an unnecessary function call. It's a slow path
anyway.

If by doing these modifications we succeed in keeping the "void"
parameters working _and_ make your stuff to compile, I think we would
have done something great. :-)

Mathieu

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Mathieu Desnoyers
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