Re: [PATCH v1 0/2] fuse io_uring: support registered buffers

[Joanne Koong <joannelkoong@gmail.com>]

On Wed, Oct 22, 2025 at 1:43 PM Bernd Schubert <bschubert@ddn.com> wrote:
>
> On 10/22/25 22:20, Joanne Koong wrote:
> > This adds support for daemons who preregister buffers to minimize the overhead
> > of pinning/unpinning user pages and translating virtual addresses. Registered
> > buffers pay the cost once during registration then reuse the pre-pinned pages,
> > which helps reduce the per-op overhead.
> >
> > This is on top of commit 211ddde0823f in the iouring tree.
>
> Interesting, on a first glance this looks like an alternative
> implementation of page pinning
>
> https://lore.kernel.org/all/20240901-b4-fuse-uring-rfcv3-without-mmap-v3-17-9207f7391444@ddn.com/
>
> At DDN we are running with that patch (changed commit message) and another
> one that avoids io_uring_cmd_complete_in_task() - with pinned pages
> the IO submitting application can directly write into header and payload
> (note that the latter also required pinned headers)
>
> Going to look into your approach tomorrow.

Thanks for taking a look when you get the chance. The libfuse changes
are in this branch
https://github.com/joannekoong/libfuse/tree/registered_buffers btw.

Thanks,
Joanne

>
>
>
> Thanks,
> Bernd