Re: [PATCH 3/4] Embed zone_id information within the zonelist->zones pointer

Christoph Lameter
2007-08-13T23:25:23Z

On Tue, 14 Aug 2007, Andi Kleen wrote:

> > But they use GFP_DMA right now and drivers cannot use DMA32 if they want
>
> The way it was originally designed was that they use GFP_DMA32,
> which would map to itself on x86-64, to GFP_DMA on ia64 and to
> GFP_KERNEL on i386. Unfortunately that seems to have bitrotted
> (perhaps I should have better documented it)

The DMA boundaries are hardware depending. A 4GB boundary
may not make sense on certain platforms.

> > to be cross platforms compatible? Doesnt the dma API completely do away
> > with these things?
>
> No GFP_DMA32 in my current plan is still there.

AFAIK GFP_DMA32 is a x86_64 special that would be easy to remove. Dealing
with physical boundaries is current done via the dma interface right? Lets
keep it there?