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Date: Wed, 15 Apr 2009 22:34:56 -0400
From: Mathieu Desnoyers <compudj@krystal.dyndns.org>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Steven Rostedt <rostedt@goodmis.org>, linux-kernel@vger.kernel.org,
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       Pekka Enberg <penberg@cs.helsinki.fi>
Subject: Re: [PATCH 2/8] tracing: create automated trace defines
Message-ID: <20090416023456.GC22378@Krystal>
References: <20090414172337.280621613@goodmis.org> <20090414172640.796858018@goodmis.org> <49E51FC1.8090306@goop.org> <20090415014548.GA7984@Krystal> <49E6065B.7080409@goop.org>
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* Jeremy Fitzhardinge (jeremy@goop.org) wrote:
> Mathieu Desnoyers wrote:
>> * Jeremy Fitzhardinge (jeremy@goop.org) 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

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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