Messages in this thread | | | Date | Thu, 25 Jul 2019 07:05:48 -0700 | From | Christoph Hellwig <> | Subject | Re: [PATCH v6 4/5] dma-buf: heaps: Add CMA heap to dmabuf heaps |
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On Thu, Jul 25, 2019 at 09:47:11AM -0400, Andrew F. Davis wrote: > This is a central allocator, it is not tied to any one device. If we > knew the one device ahead of time we would just use the existing dma_alloc. > > We might be able to solve some of that with late mapping after all the > devices attach to the buffer, but even then, which device's CMA area > would we chose to use from all the attached devices? > > I can agree that allocating from per-device CMA using Heaps doesn't make > much sense, but for global pools I'm not sure I see any way to allow > devices to select which pool is right for a specific use. They don't > have the full use-case information like the application does, the > selection needs to be made from the application.
Well, the examples we had before was that we clear want to use the per-device CMA area. And at least in upstream a CMA area either is global or attached to a device, as we otherwise wouldn't find it.
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