Messages in this thread | | | Date | Thu, 22 Jul 2010 09:28:20 -0700 | From | Zach Pfeffer <> | Subject | Re: [RFC 1/3 v3] mm: iommu: An API to unify IOMMU, CPU and device memory management |
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On Thu, Jul 22, 2010 at 08:39:17AM +0100, Russell King - ARM Linux wrote: > On Wed, Jul 21, 2010 at 09:30:34PM -0700, Zach Pfeffer wrote: > > This goes to the nub of the issue. We need a lot of 1 MB physically > > contiguous chunks. The system is going to fragment and we'll never get > > our 12 1 MB chunks that we'll need, since the DMA API allocator uses > > the system pool it will never succeed. > > By the "DMA API allocator" I assume you mean the coherent DMA interface, > The DMA coherent API and DMA streaming APIs are two separate sub-interfaces > of the DMA API and are not dependent on each other.
I didn't know that, but yes. As far as I can tell they both allocate memory from the VM. We'd need a way to hook in our our own minimized mapping allocator.
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