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

[Andi Kleen <ak@suse.de>]

On Mon, Aug 13, 2007 at 03:09:55PM -0700, Christoph Lameter wrote:
> > > > 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.

Yes, but ZONE_DMA32 == ZONE_DMA.

Also when the slab users of GFP_DMA are all gone ia64 won't need
the slab support anymore. So either you change your ifdef in slub or 
switch to ZONE_DMA32 for IA64.

The trouble is that this cannot be done globally, at least not
until s390 and a few other architures using GFP_DMA with slab
are all converted.

> 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.

But it's not quite the same: GFP_DMA32 has no explicit slab support.

-Andi