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To: David Wei <dw@davidwei.uk>, Jason Gunthorpe <jgg@ziepe.ca>,
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From: Pavel Begunkov <asml.silence@gmail.com>
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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.

The devmem TCP callback can implement it in a way feasible to
the project, but it cannot directly post events to an unrelated
API like io_uring. And devmem attaches buffers to a socket,
for which a ring for returning buffers might even be a nuisance.

-- 
Pavel Begunkov