[Xen-devel] Re: mthca use of dma_sync_single is bogus

[Lukas Hejtmanek <xhejtman@xxxxxxxxxxx>]

On Tue, Jul 10, 2007 at 11:06:29AM -0700, Roland Dreier wrote:
> > And what about the attached patch to mthca_memfree? It changes alloc_pages 
> > for  pci_alloc_consistent. Using it, I can enable FMR and the driver 
> > runs fine.
> 
> As Michael said, this uses a lot of consistent memory.  Probably too
> much on some systems.

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.

And moreover, it avoids using swiotlb and bounce buffers, I think. Am I right,
Keir?

-- 
Lukáš Hejtmánek

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