Re: Does kmalloc always return address below 4GB?

David Mosberger
2002-03-05T16:46:10Z

>>>>> On Tue, 05 Mar 2002 07:47:22 -0800 (PST), "David S. Miller" <davem@redhat.com> said:

DaveM> I know pci_map_single (and _sg) will use bounce buffers on
DaveM> platforms without an IOMMU,

DaveM> 64-bit platforms without IOMMU use HIGHMEM.

Not true for ia64 linux.

DaveM> It could for example be solved with a GFP_32BIT flag or
DaveM> something (on IA64 I know GFP_DMA is used in
DaveM> pci_alloc_consistent() to get memory below 4GB but that can't
DaveM> be used on all platforms).

DaveM> IA64 was broken, it now uses HIGHMEM.

No it doesn't. Perhaps you meant to say that the Red Hat version of
the ia64 linux kernel uses highmem?

--david