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From: Mina Almasry <almasrymina@google.com>
Date: Mon, 10 Jun 2024 08:41:25 -0700
Message-ID: <CAHS8izNwmXQTLc9VADpushYKyeJ4ZY4G9aV47W2-1St65-tKUg@mail.gmail.com>
Subject: Re: [PATCH net-next v10 02/14] net: page_pool: create hooks for
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To: =?UTF-8?Q?Christian_K=C3=B6nig?= <christian.koenig@amd.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>, Pavel Begunkov <asml.silence@gmail.com>, David Wei <dw@davidwei.uk>, 
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	Shailend Chand <shailend@google.com>, Harshitha Ramamurthy <hramamurthy@google.com>, 
	Shakeel Butt <shakeel.butt@linux.dev>, Jeroen de Borst <jeroendb@google.com>, 
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On Mon, Jun 10, 2024 at 5:38=E2=80=AFAM Christian K=C3=B6nig
<christian.koenig@amd.com> wrote:
>
> Am 10.06.24 um 14:16 schrieb Jason Gunthorpe:
> > On Mon, Jun 10, 2024 at 02:07:01AM +0100, Pavel Begunkov wrote:
> >> On 6/10/24 01:37, David Wei wrote:
> >>> On 2024-06-07 17:52, Jason Gunthorpe wrote:
> >>>> IMHO it seems to compose poorly if you can only use the io_uring
> >>>> lifecycle model with io_uring registered memory, and not with DMABUF
> >>>> memory registered through Mina's mechanism.
> >>> By this, do you mean io_uring must be exclusively used to use this
> >>> feature?
> >>>
> >>> And you'd rather see the two decoupled, so userspace can register w/ =
say
> >>> dmabuf then pass it to io_uring?
> >> Personally, I have no clue what Jason means. You can just as
> >> well say that it's poorly composable that write(2) to a disk
> >> cannot post a completion into a XDP ring, or a netlink socket,
> >> or io_uring's main completion queue, or name any other API.
> > There is no reason you shouldn't be able to use your fast io_uring
> > completion and lifecycle flow with DMABUF backed memory. Those are not
> > widly different things and there is good reason they should work
> > together.
>
> Well there is the fundamental problem that you can't use io_uring to
> implement the semantics necessary for a dma_fence.
>
> That's why we had to reject the io_uring work on DMA-buf sharing from
> Google a few years ago.
>

Any chance someone can link me to this? io_uring, as far as my
primitive understanding goes, is not yet very adopted at Google, and
I'm curious what this effort is.

--=20
Thanks,
Mina