Messages in this thread | | | Date | Thu, 20 Dec 2007 15:22:13 -0600 | From | Steve Wise <> | Subject | Re: [ofa-general] iommu dma mapping alignment requirements |
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Benjamin Herrenschmidt wrote: > On Thu, 2007-12-20 at 13:29 -0600, Steve Wise wrote: > >> Or based on the alignment of vaddr actually... > > The later wouldn't be realistic. What I think might be necessay, though > it would definitely cause us problems with running out of iommu space > (which is the reason we did the switch down to 4K), is to provide > alignment to the real page size, and alignement to the allocation order > for dma_map_consistent. > > It might be possible to -tweak- and only provide alignment to the page > size for allocations that are larger than IOMMU_PAGE_SIZE. That would > solve the problem with small network packets eating up too much iommu > space though. > > What do you think ?
That might work.
If you gimme a patch, i'll try it out!
Steve.
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