Re: Does kmalloc always return address below 4GB?

David S. Miller
2002-03-05T15:50:10Z

From: Steffen Persvold <sp@scali.com>
Date: Tue, 05 Mar 2002 16:43:01 +0100

"David S. Miller" wrote:
> Just use pci_alloc_consistent, it never gives you
> anything larger than 32-bit addresses, please read the
> documentation :-)

What about memory for streaming mappings

That's a different story.

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

64-bit platforms without IOMMU use HIGHMEM.

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

IA64 was broken, it now uses HIGHMEM.

Franks a lot,
David S. Miller
davem@redhat.com