Re: [PATCH][GIT PULL][v3.3] tracing: Add header wrappers event_headers_start.h and event_headers_end.h

From: Rusty Russell
Date: Sun Jan 22 2012 - 18:59:27 EST


On Wed, 18 Jan 2012 12:56:52 -0500, Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> On Wed, 2012-01-18 at 13:07 +0100, Ingo Molnar wrote:
>
> > I'd argue that __raise_softirq_irqoff() should not be inline -
> > that would solve a whole host of issues. Event tracing is
> > enabled in most distros so there's no real overhead argument to
> > be made here either - so it's probably a bit faster in fact to
> > have this uninlined. What do you think?
>
> Sure, I have no problem moving that out of the header. I don't think
> raising a softirq is in that critical a path that it can't be a function
> call.
>
> There's only one trace/events header left which is in module.h. Perhaps
> we can move __module_get() and try_module_get() out of the header. We
> could just move the "if" part out.

Agreed. Since GCC should be able to eliminate that branch in almost all
cases, since it's usually a literal NULL or address of a (non-weak)
symbol.

Be interesting to see the before/after sizes with this out-of-line.

Thanks,
Rusty.
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