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Date: Thu, 16 Apr 2009 09:42:48 -0400 (EDT)
From: Steven Rostedt <rostedt@goodmis.org>
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To: Christoph Hellwig <hch@infradead.org>
cc: Jeremy Fitzhardinge <jeremy@goop.org>,
       Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
       Ingo Molnar <mingo@elte.hu>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Problem with CREATE_TRACE_POINTS and recursion safety
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On Thu, 16 Apr 2009, Christoph Hellwig wrote:

> On Wed, Apr 15, 2009 at 11:09:14PM -0400, Steven Rostedt wrote:
> > I hate to do this because it adds some more work to the developer adding a 
> > new trace point header, but we could just remove the CREATE_TRACE_POINTS 
> > and do in the trace/events/*.h headers:
> > 
> > #ifdef CREATE_FOO_TRACE_POINTS
> > #include <trace/define_trace.h>
> > #endif
> > 
> > in all tracepoint headers. I originally had it this way with just the 
> > CREATE_TRACE_POINTS, but Christoph Hellwig and Mathieu both suggested 
> > putting that into define_trace.h.  It seems so much cleaner to keep it in 
> > define_trace.h, but if it is causing too many headaches, it may not be 
> > worth it :-/
> 
> I still don't like the magic include in every trace header.
> 
> What about
> 
> #define CREATE_FOO_TRACE_POINTS	"subsystem"
> 
> to only create them for a given subsystem?

I tried this. But it seems that there's no way to compare strings with the 
preprocessor. You can compare numbers, but having each subsystem define 
its own number would be a pain to manage.

-- Steve