Re: [PATCH v9 00/17] fuse: fuse-over-io-uring.

[Ming Lei <tom.leiming@gmail.com>]

On Tue, Jun 24, 2025 at 5:36 AM Bernd Schubert <bernd@bsbernd.com> wrote:
>
>
>
> On 6/20/25 03:39, xiaobing.li wrote:
> > On Wed, Jun 18, 2025 at 09:30:51PM -0600, Keith Busch wrote:
> >> On Wed, Jun 18, 2025 at 03:13:41PM +0200, Bernd Schubert wrote:
> >>> On 6/18/25 12:54, xiaobing.li wrote:
> >>>>
> >>>> Hi Bernd,
> >>>>
> >>>> Do you have any plans to add zero copy solution? We are interested in
> >>>> FUSE's zero copy solution and conducting research in code.
> >>>> If you have no plans in this regard for the time being, we intend to
> >>>>  submit our solution.
> >>>
> >>> Hi Xiobing,
> >>>
> >>> Keith (add to CC) did some work for that in ublk and also planned to
> >>> work on that for fuse (or a colleague). Maybe Keith could
> >>> give an update.
> >>
> >> I was initially asked to implement a similar solution that ublk uses for
> >> zero-copy, but the requirements changed such that it won't work. The
> >> ublk server can't directly access the zero-copy buffers. It can only
> >> indirectly refer to it with an io_ring registered buffer index, which is
> >> fine my ublk use case, but the fuse server that I was trying to
> >> enable does in fact need to directly access that data.
> >>
> >> My colleauge had been working a solution, but it required shared memory
> >> between the application and the fuse server, and therefore cooperation
> >> between them, which is rather limiting. It's still on his to-do list,
> >> but I don't think it's a high priority at the moment. If you have
> >> something in the works, please feel free to share it when you're ready,
> >> and I would be interested to review.
> >
> > Hi Bernd and Keith,
> >
> > In fact, our current idea is to implement a similar solution that ublk uses
> > for zero-copy. If this can really further improve the performance of FUSE,
> > then I think it is worth trying.
> > By the way, if it is convenient, could you tell me what was the original
> > motivation for adding io_uring, or why you want to improve the performance
> > of FUSE and what you want to apply it to?
>
> At DDN we have mainly a network file system using fuse - the faster it
> runs the better. But we need access to the data for erasure,
> compression, etc. Zero-copy would be great, but I think it is

BTW, the current ublk io_uring zero copy may be extended with ebpf uring_op
for supporting standard compression & checksum too, and Android has
similar requirements too:

https://lpc.events/event/18/contributions/1710/attachments/1440/3070/LPC2024_ublk_zero_copy.pdf



Thanks,
Ming Lei