Re: [ltt-dev] [PATCH] tracepoints: Generate Module.tracepoints file

[Mathieu Desnoyers <compudj at krystal dot dyndns dot org>]

* Frank Ch. Eigler (fche@redhat.com) wrote:
> Jan Blunck <jblunck@suse.de> writes:
> 
> > This adds support to generate the Module.tracepoints file by modpost. This
> > can be read by tools like SystemTap very similar to the Module.markers file.
> > [...]
> 
> For systemtap, the problem with tracepoints is not so much knowing the
> list of them, but knowing how to dynamically interface to them.  In
> particular, the parameter type signatures are a problem because they
> can be general C type decls, which are hard just to parse.
> 

Why would you want to deal with tracepoints dynamically ? They are meant
to be fixed in-kernel API. when an in-kernel API changes, you just adapt
the code accordingly. Therefore, I don't see why you would try to follow
these changes "automatically" ?

To me, it makes as much sense as trying to follow EXPORT_SYMBOL*() or
any kernel API automatically.

And remember, tracepoints are meant to be few, well thought and not to
cange too often once things settle down.

OTOH, markers can be used as temporary debugging statements, which makes
it understandable to follow their changes dynamically.

Mathieu

> - FChE
> 
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-- 
Mathieu Desnoyers
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