On Tue, Jul 10, 2007 at 12:08:43PM -0700, Roland Dreier wrote:
> > I think he spoke about coherent, didn't he? On i386/x86_64, the consistent
> and
> > coherent are the same but on some architectures they are not and I think
> that
> > using consistent (in particular pci_alloc_consistent) is exactly what
> should
> > be used. Keir also recommended to use this one.
>
> coherent and consistent are synonyms. It's confusing because there is
> pci_alloc_consistent(), which is in general just a wrapper for
> dma_alloc_coherent().
According to DMA-mapping.txt they are not. Alpha, M68000 wihtout MMU, PPC,
Sparc, Sparc64, V850 have own implementation of pci_alloc_consistent().
Yes, on i386, the pci_alloc_consistent() is just wrapper for
dma_alloc_coherent().
> > And moreover, it avoids using swiotlb and bounce buffers, I think. Am I
> right,
> > Keir?
>
> Yes, but I'm not really willing to make things worse for standard i386
> just to make Xen work a little better.
So, what about some #ifdefs ? E.g., allow config option - Xen optimizations?
--
Lukáš Hejtmánek
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