Re: [Xen-devel] [PATCH 03 of 38] swiotlb: allow architectures tooverrideswiotlb pool allocation

From: Jeremy Fitzhardinge
Date: Fri Nov 14 2008 - 14:33:29 EST


Jan Beulich wrote:
Not directly related to this patch alone, but to the combined set of changes
to swiotlb: I don't see any handling of CONFIG_HIGHMEM here (or at least
a note that this a known limitation needing work). I mention this because
this was the largest part of the changes I had posted long ago to make
lib/swiotlb.c Xen-ready, and which got rejected due to their ugliness.

Was that Andi's objection on the grounds that he didn't think that Xen should need swiotlb at all?

I have to admit I didn't follow that thread very closely (or threads, as I seem to remember). Do you have a pointer to the pertinent bits?

While perhaps less intrusive to take care of, I also didn't see an equivalent
of the range_straddles_page_boundary() logic, without which I can't see
how this would work in the common case.
Could you be more specific? The swiotlb allocation should be machine contiguous and so there's no stradding required, but I think I'm missing your point.

J
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