On Tue, May 07, 2024 at 06:25:52PM +0100, Pavel Begunkov wrote:
On 5/7/24 17:48, Jason Gunthorpe wrote:
On Tue, May 07, 2024 at 09:42:05AM -0700, Mina Almasry wrote:
- Align with devmem TCP to use udmabuf for your io_uring memory. I
think in the past you said it's a uapi you don't link but in the face of this pushback you may want to reconsider.
dmabuf does not force a uapi, you can acquire your pages however you want and wrap them up in a dmabuf. No uapi at all.
The point is that dmabuf already provides ops that do basically what is needed here. We don't need ops calling ops just because dmabuf's ops are not understsood or not perfect. Fixup dmabuf.
Those ops, for example, are used to efficiently return used buffers back to the kernel, which is uapi, I don't see how dmabuf can be fixed up to cover it.
Sure, but that doesn't mean you can't use dma buf for the other parts of the flow. The per-page lifetime is a different topic than the refcounting and access of the entire bulk of memory.
Jason