Re: [Linux-ia64] patch to no longer use ia64's software mmu

David Mosberger (davidm@hpl.hp.com)
Tue, 4 Dec 2001 10:14:44 -0800


>>>>> On Tue, 4 Dec 2001 18:19:55 +0000 (GMT), Alan Cox <alan@lxorguk.ukuu.org.uk> said:

Alan> I don't see the need: GFP_DMA is the ISA DMA zone. pci_* API
Alan> is used by everyone else [for 2.5].
>> Without a 4GB zone, you may end up creating bounce buffers
>> needlessly for 32-bit capable DMA devices, no?

Alan> Yes - but it becomes an implementation detail. Drivers don't
Alan> go around asking for kmalloc in 4Gb zone anymore they ask for
Alan> PCI memory that a 32bit pci address can hit. I'm sure a 4Gb
Alan> zone is what will be there internally but you don't need
Alan> GFP_4GBZONE as a visible driver detail.

Oh, OK, we're in agreement then. When I looked at the zone stuff the
last time, I didn't think you could have an internal 4GB zone without
abusing an existing zone making some changes to the header files in
linux/*.h, but perhaps I missed something.

--david
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