Re: [RFC PATCH v2 00/11] Device Memory TCP

[Mina Almasry <almasrymina@google.com>]

On Thu, Aug 17, 2023 at 11:04 AM Pavel Begunkov <asml.silence@gmail.com> wrote:
>
> On 8/14/23 02:12, David Ahern wrote:
> > On 8/9/23 7:57 PM, Mina Almasry wrote:
> >> Changes in RFC v2:
> >> ------------------
> ...
> >> ** Test Setup
> >>
> >> Kernel: net-next with this RFC and memory provider API cherry-picked
> >> locally.
> >>
> >> Hardware: Google Cloud A3 VMs.
> >>
> >> NIC: GVE with header split & RSS & flow steering support.
> >
> > This set seems to depend on Jakub's memory provider patches and a netdev
> > driver change which is not included. For the testing mentioned here, you
> > must have a tree + branch with all of the patches. Is it publicly available?
> >
> > It would be interesting to see how well (easy) this integrates with
> > io_uring. Besides avoiding all of the syscalls for receiving the iov and
> > releasing the buffers back to the pool, io_uring also brings in the
> > ability to seed a page_pool with registered buffers which provides a
> > means to get simpler Rx ZC for host memory.
>
> The patchset sounds pretty interesting. I've been working with David Wei
> (CC'ing) on io_uring zc rx (prototype polishing stage) all that is old
> similar approaches based on allocating an rx queue. It targets host
> memory and device memory as an extra feature, uapi is different, lifetimes
> are managed/bound to io_uring. Completions/buffers are returned to user via
> a separate queue instead of cmsg, and pushed back granularly to the kernel
> via another queue. I'll leave it to David to elaborate
>
> It sounds like we have space for collaboration here, if not merging then
> reusing internals as much as we can, but we'd need to look into the
> details deeper.
>

I'm happy to look at your implementation and collaborate on something
that works for both use cases. Feel free to share unpolished prototype
so I can start having a general idea if possible.

> > Overall I like the intent and possibilities for extensions, but a lot of
> > details are missing - perhaps some are answered by seeing an end-to-end
> > implementation.
>
> --
> Pavel Begunkov



-- 
Thanks,
Mina