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

Christoph Lameter
2007-08-13T22:09:55Z

On Tue, 14 Aug 2007, Andi Kleen wrote:

> On Mon, Aug 13, 2007 at 03:00:14PM -0700, Christoph Lameter wrote:
> > You said that ZONE_DMA will still be there right? So the zone will be
>
> There will be a (variable sized) dma zone, but not a ZONE_DMA entry in pgdat
> or in the the fallback lists.

Ahh.. Okay.

> > > There are still other architectures that use it. Biggest offender
> > > is s390. I'll leave them to their respective maintainers.
> >
> > IA64 also uses ZONE_DMA to support 32bit controllers.
>
> ZONE_DMA32 I thought? That one is not changed.

x86_64 is the only platforms that uses ZONE_DMA32. Ia64 and other 64 bit
platforms use ZONE_DMA for <4GB allocs.

> > If so then it may be better to drop ZONE_DMA32 and make ZONE_DMA be below
> > 4GB like other 64bit arches.
>
> That might be possible as a followup, but would change the driver
> API. Is it worth it?

It would leave the driver API as is for many arches.

I think s/ZONE_DMA32/ZONE_DMA would restore the one DMA zone thing which
is good. We could drop all ZONE_DMA32 stuff that is only needed by a
single arch.