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[Xen-devel] Re: [ofa-general] Re: mthca use of dma_sync_single is bogus
- To: "Michael S. Tsirkin" <mst@xxxxxxxxxxxxxxxxxx>
- From: Roland Dreier <rdreier@xxxxxxxxx>
- Date: Tue, 10 Jul 2007 12:25:59 -0700
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- Cc: Lukas Hejtmanek <xhejtman@xxxxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx, Keir Fraser <keir@xxxxxxxxxxxxx>, general@xxxxxxxxxxxxxxxxxxxxx
- Delivery-date: Tue, 17 Jul 2007 05:03:31 -0700
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- List-id: Xen developer discussion <xen-devel.lists.xensource.com>
> Hmm. This means there's no way to sync a range within
> mapping created with map_sg?
It doesn't seem that there is one right now at least.
> > It actually doesn't look too bad to replace our use of pci_map_sg()
> > with dma_map_single(), at least at first glance. I'll try to write a
> > patch later.
> Well, the reason map_sg is there is presumably because on some
> architectures it's worth it to try and make the region contigious in DMA
> But I agree this seems the lesser evil at this point ...
Given that we're already trying to allocate big chunks of physically
contiguous memory, I think that any virtual merging we get is likely
to be of very small benefit.
It is kind of a shame to give this up though.
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