Re: [PATCH] Documentation/trace: Correcting and extending tracepointdocumentation

[Zoltan Kiss]

Hi,

I'm not very familiar with the tracing framework, but I will try to 
comment on your questions.

On 25/08/13 09:59, Rob Landley wrote:
> On 08/22/2013 04:49:31 PM, Zoltan Kiss wrote:
> > +#if !defined(_TRACE_SUBSYS_H) || defined(TRACE_HEADER_MULTI_READ)
> > +#define _TRACE_SUBSYS_H
>
> But this makes no sense to me: why is it needed? (I.E. why must it be
> block copied into each _user_ of tracepoints?)
This is to prevent header reinclusion, the second condition makes it 
possible to include it again from trace/define_trace.h

> >  #include <linux/tracepoint.h>
> >
> > @@ -48,10 +54,16 @@ DECLARE_TRACE(subsys_eventname,
> >      TP_PROTO(int firstarg, struct task_struct *p),
> >      TP_ARGS(firstarg, p));
> >
> > +#endif /* _TRACE_SUBSYS_H */
> > +
> > +/* This part must be outside protection */
> > +#include <trace/define_trace.h>
> > +
>
> Why? (Both why do you need to #include a header outside a multiple
> inclusion guard, and why is the additional header needed at all in
> _every_ subsystem trace header?)
I see only one inclusion guard here, the one above. define_trace.h 
should take effect at only one place, where CREATE_TRACE_POINTS is 
defined, to create the tracepoints exactly once. However I don't see as 
well why it should be outside protection. Maybe because the intentional 
header reinclusion in it?

Regards,

Zoli

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/