Re: [RFC patch 08/18] cnt32_to_63 should use smp_rmb()

Harvey Harrison
2008-11-07T18:30:38Z

On Fri, 2008-11-07 at 10:21 -0800, Andrew Morton wrote:
> On Fri, 7 Nov 2008 13:00:41 -0500
> Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> wrote:
> > > It's one of those things I hope I never need to know about, but perhaps
> > > we do somewhere have static storage in an inline. Wouldn't surprise
> > > me, and I bet that if we do, it's a bug.
> >
> > Tracepoints actually use that.
>
> Referring to include/linux/tracepoint.h:DEFINE_TRACE()?
>
> It does look a bit fragile. Does every .c file which included
> include/trace/block.h get a copy of __tracepoint_block_rq_issue,
> whether or not it used that tracepoint? Hopefully not.
>
> > It could be changed so they use :
> >
> > DECLARE_TRACE() (in include/trace/group.h)
> > DEFINE_TRACE() (in the appropriate kernel c file)
> > trace_somename(); (in the code)
> >
> > instead. That would actually make more sense and remove the need for
> > multiple declarations when the same tracepoint name is used in many
> > spots (this is a problem kmemtrace has, it generates a lot of tracepoint
> > declarations).

Could this scheme also help with the thousands of sparse warnings that
kmemtrace produces because of the current arrangement, all of the form:

include/linux/kmemtrace.h:33:2: warning: Initializer entry defined twice
include/linux/kmemtrace.h:33:2: also defined here

As you could have unique names for the tracepoints now, rather than the
'unique' static storage? Or am I off-base here?

Harvey