Re: [PATCH, RFC] sputrace: use the generic event tracer

[Steven Rostedt <srostedt@redhat.com>]

On Wed, 2009-05-06 at 13:23 +0200, Ingo Molnar wrote:

> > > > +# magic for the trace events
> > > > +CFLAGS_sched.o := -I$(src)
> > > 
> > > Steve, i'm wondering whether this type of Makefile hackery (caused 
> > > by modular tracepoints) could be eliminated ...
> > 
> > We would just have to include the header file with "" instead of 
> > <>. But I remember Steve not liking this when we talked about it.
> 
> Yeah. But changing Makefiles isnt particularly clean either ...
> 
> And adding -I$(src) can have side-effects: we often have a local 
> foo.h while an include/linux/foo.h as well.

That still would not conflict, because

#include "foo.h"

will not include "linux/foo.h" and

#include <linux/foo.h>

will not include a local foo.h, unless there's also a local "linux"
directory with a foo.h in it.


The Makefile hack has to do with being able to have the "foo.h" file
with the TRACE_EVENTs someplace other than include/trace.

If the "foo.h" is in include/trace.h we do not need to include this
hack. But because the include/trace/define_trace.h needs to include the
"foo.h" file recursively, it must be able to find it. If we do not add a
search path, include/trace/define_trace.h will not look in the other
locations.

Note, as Christoph did, we only need to add the include path to the file
that defines "CREATE_TRACE_POINTS". Which is only one file.

CFLAGS_sched.o := -I$(src)

Only touches the sched.c file in that directory (Note, for those reading
this thread out of context, this is not the same file as kernel/sched.c)

-- Steve