Messages in this thread | | | Date | Tue, 4 Jul 2006 08:10:54 -0700 (PDT) | From | Christoph Lameter <> | Subject | Re: [RFC 0/8] Reduce MAX_NR_ZONES and remove useless zones. |
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On Tue, 4 Jul 2006, Christoph Hellwig wrote:
> On Mon, Jul 03, 2006 at 04:26:57PM -0700, Christoph Lameter wrote: > > > Which btw is utterly wrong. It should have a 4GB ZONE_DMA32 and everything > > > else in ZONE_NORMAL. > > > > So we want to change the definition of ZONE_DMA to refer to the first 16MB > > only? ZONE_DMA32 is always a 4GB border? > > The definition of ZONE_DMA32 is to be te 32bit border. I think we should > implement it wherever possible but at least on all architectures that > maybe have non-iommu implementations. ZONE_DMA should be an arch-specific > low memory zone.
I guess then we should drop ZONE_DMA (its a misnoner anyways since it seems to indicate that DMA is only possible in this zone). Instead use
ZONE_ISA_DMA -> ISA DMA Area (16 MB boundary) ZONE_32BIT_DMA -> 32bit DMA area (well 900 MB on x86_64 but somewhere in that area) only used for 64 bit platforms with 32 bit devices. <and maybe define new ones in the future?>
Some arches seem to make ZONE_DMA their default zone instead of ZONE_NORMAL if DMA is possible to all of memory. I think in that case we should have no ZONE_DMA at all.
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