On Thu, Oct 24, 2024 at 05:40:02PM +0100, Pavel Begunkov wrote: > On 10/24/24 17:06, Christoph Hellwig wrote: > > On Thu, Oct 24, 2024 at 03:23:06PM +0100, Pavel Begunkov wrote: > > > > That's not what this series does. It adds the new memory_provider_ops > > > > set of hooks, with once implementation for dmabufs, and one for > > > > io_uring zero copy. > > > > > > First, it's not a _new_ abstraction over a buffer as you called it > > > before, the abstraction (net_iov) is already merged. > > > > Umm, it is a new ops vector. > > I don't understand what you mean. Callback? struct memory_provider_ops. It's a method table or ops vetor, no callbacks involved. > Then please go ahead and take a look at the patchset in question > and see how much of dmabuf handling is there comparing to pure > networking changes. The point that it's a new set of API and lots > of changes not related directly to dmabufs stand. dmabufs is useful > there as an abstraction there, but it's a very long stretch saying > that the series is all about it. I did take a look, that's why I replied. > > > on an existing network specific abstraction, which are not restricted to > > > pages or anything specific in the long run, but the flow of which from > > > net stack to user and back is controlled by io_uring. If you worry about > > > abuse, io_uring can't even sanely initialise those buffers itself and > > > therefore asking the page pool code to do that. > > > > No, I worry about trying to io_uring for not good reason. This > > It sounds that the argument is that you just don't want any > io_uring APIs, I don't think you'd be able to help you with > that. No, that's complete misinterpreting what I'm saying. Of course an io_uring API is fine. But tying low-level implementation details to to is not. > > pre-cludes in-kernel uses which would be extremly useful for > > Uses of what? devmem TCP is merged, I'm not removing it, > and the net_iov abstraction is in there, which can be potentially > be reused by other in-kernel users if that'd even make sense. How when you are hardcoding io uring memory registrations instead of making them a generic dmabuf? Which btw would also really help with pre-registering the memry with the iommu to get good performance in IOMMU-enabled setups.
