[parisc-linux] ZONE_DMA

Matthew Wilcox matthew@wil.cx
Mon, 1 Jan 2001 18:55:57 +0000


On Mon, Jan 01, 2001 at 06:32:11PM +0000, Alan Cox wrote:
> Or know something about their hardware being crap.

Hm.

> > So how should we be populating our zones?  Put all of our memory in
> > ZONE_DMA, like ppc, since the only people who'll be specifying GFP_DMA
> > will have done so incorrectly?  Put the first 16MB of it in there,
> 
> That is a very dangerous assumption (as some PPC people have discovered when
> they DMA stuff into the wrong place)
> 
> > since we might support ISA some day?  Put none of it in there on the
> > grounds we don't support ISA at all?
> 
> I think none is safer. pci_alloc_consistent seems to address all the stuff
> we worry about. 

But if we have none, then all GFP_DMA allocations will fail.  Which
includes the scsi midlayers.  Ooh, I just noticed that scsi_scan.c
is broken...  expect a patch RSN.

-- 
Revolutions do not require corporate support.