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From: Andi Kleen <ak@suse.de>
To: "Ray Bryant" <raybry@mpdtxmail.amd.com>
Subject: Re: [PATCH/RFC] Shared page tables
Date: Tue, 24 Jan 2006 01:39:46 +0100
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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
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