Re: [Q] Why does dma_alloc_coherent() of ia64 GFP_DMA?

[Christoph Lameter]

On Tue, 11 Nov 2008, FUJITA Tomonori wrote:

> Is it because it does some kinda address translation
> (provider->dma_map_consistent) later? The zone flag is meaningless if
> you do sorta address translation (e.g. hardware IOMMU like VT-d).

Yes it can do address translation. Therefore a < 4G address can show up at
any 64 bit address. So no need for a special DMA zone. The same is true
for more x86_64 platforms that have an IOMMU.


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