Re: [PATCH 1/7] Introduce the pagetable_operations and associatedhelper macros.

[Nick Piggin]

William Lee Irwin III wrote:
> Adam Litke wrote:
>
> > > 	struct vm_operations_struct * vm_ops;
> > > +	const struct pagetable_operations_struct * pagetable_ops;
>
>
> On Wed, Mar 21, 2007 at 03:18:30PM +1100, Nick Piggin wrote:
>
> > Can you remind me why this isn't in vm_ops?
> > Also, it is going to be hugepage-only, isn't it? So should the naming be
> > changed to reflect that? And #ifdef it...
>
>
> ISTR potential ppc64 users coming out of the woodwork for something I
> didn't recognize the name of, but I may be confusing that with your
> patch. I can implement additional users (and useful ones at that)
> needing this in particular if desired.

Yes I would be interested in seeing useful additional users of this
that cannot use our regular virtual memory, before making it a general
thing.

I just don't want to see proliferation of these things, if possible.

> Adam Litke wrote:
>
> > > +struct pagetable_operations_struct {
> > > +	int (*fault)(struct mm_struct *mm,
>
>
> On Wed, Mar 21, 2007 at 03:18:30PM +1100, Nick Piggin wrote:
>
> > I got dibs on fault ;)
> > My callback is a sanitised one that basically abstracts the details of the
> > virtual memory mapping away, so it is usable by drivers and filesystems.
> > You actually want to bypass the normal fault handling because it doesn't
> > know how to deal with your virtual memory mapping. Hmm, the best suggestion
> > I can come up with is handle_mm_fault... unless you can think of a better
> > name for me to use.
>
>
> Two fault handling methods callbacks raise an eyebrow over here at least.
> I was vaguely hoping for unification of the fault handling callbacks.

I don't know if it would be so clean to do that as they are at different levels.
Adam's fault is before the VM translation (and bypasses it), and mine is after.

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