Re: Replacement for page fault notifiers?

Arjan van de Ven
2008-01-10T00:55:53Z

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

> Arjan van de Ven <arjan@infradead.org> 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.

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