Re: Replacement for page fault notifiers?

[Arjan van de Ven]

On Thu, 10 Jan 2008 01:47:16 +0100
Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:

> Arjan van de Ven <arjan@xxxxxxxxxxxxx> writes:
> >
> > I'm btw all in favor of making mmio tracing full fledged kernel
> > infrastructure. This doesn't mean "notifier" imo; this means a real
> > flag in the struct page, and then the page fault code can do
> >
> > if (page->flags & FLAG_MMIO_TRACED)
> > 	mmio_trace(page, regs, whatever..);
> >
> > (probably surrounded by a CONFIG_ ifdef)
> > THis is a TON lighter than a notifier chain, and actually what you
> > want, you don't really want a notifier, you want a call back when a
> > special kind of page is touched.
> 
> That would assume that your mmio area has a struct page. In most PCs 
> the ones in the PCI hole don't
> 

so you also call the function for all traps on pages without struct page;
that should be extremely rare anyway, and the mmio_trace code can then 
look the page up.

-- 
If you want to reach me at my work email, use arjan@xxxxxxxxxxxxxxx
For development, discussion and tips for power savings, 
visit http://www.lesswatts.org
--
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/