Re: dma_mapping_ops for i386

From: Muli Ben-Yehuda
Date: Wed Jun 27 2007 - 16:28:51 EST


On Wed, Jun 27, 2007 at 05:26:50PM +0200, Andi Kleen wrote:

> See the recent "quiet down swiotlb warnings" thread which uncovered
> quite some corpses in Xen's current IO setup.
>
> Xen apparently bounces for multi page IOs which get merged from block
> lists because the block layer doesn't know they are not really
> continuous in machine memory.
>
> Proper fix is to tell the block layer to not merge in the first
> place instead.
>
> And probably some similar mechanism for network drivers that limits
> MTUs.

Will that guarantee that block and net IOs will not straddle a page
boundary?

Cheers,
Muli
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