Re: copy on write for splice() from file to pipe?

[Linus Torvalds]

On Fri, Feb 10, 2023 at 12:39 PM Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> Right, I'm referencing doing zerocopy data sends with io_uring, using
> IORING_OP_SEND_ZC. This isn't from a file, it's from a memory location,
> but the important bit here is the split notifications and how you
> could wire up a OP_SENDFILE similarly to what Andy described.

Sure, I think it's much more reasonable with io_uring than with splice itself.

So I was mainly just reacting to the "strict-splice" thing where Andy
was talking about tracking the page refcounts. I don't think anything
like that can be done at a splice() level, but higher levels that
actually know about the whole IO might be able to do something like
that.

Maybe we're just talking past each other.

             Linus