Re: [PATCH/RFC] Shared page tables

Andi Kleen
2006-01-24T00:39:46Z

On Tuesday 24 January 2006 01:16, Ray Bryant wrote:
> On Monday 23 January 2006 17:58, Ray Bryant wrote:
> <snip>
>
> > ... And what kind of alignment constraints do we end up
> > under in order to make the sharing happen? (My guess would be that there
> > aren't any such constraints (well, page alignment.. :-) if we are just
> > sharing pte's.)
> >
>
> Oh, obviously that is not right as you have to share full pte pages. So on
> x86_64 I'm guessing one needs 2MB alignment in order to get the sharing to
> kick in, since a pte page maps 512 pages of 4 KB each.

The new randomized mmaps will likely actively sabotate such alignment. I just
added them for x86-64.

-Andi