[CRIU] [PATCH bpf-next v1 1/8] io_uring: Implement eBPF iterator for registered buffers

[Alexei Starovoitov]

On Thu, Nov 18, 2021 at 9:17 PM Kumar Kartikeya Dwivedi
<memxor at gmail.com> wrote:
>
> On Fri, Nov 19, 2021 at 10:26:59AM IST, Alexei Starovoitov wrote:
> > On Fri, Nov 19, 2021 at 09:45:23AM +0530, Kumar Kartikeya Dwivedi wrote:
> > >
> > > Also, this work is part of GSoC. There is already code that is waiting for this
> > > to fill in the missing pieces [0]. If you want me to add a sample/selftest that
> > > demonstrates/tests how this can be used to reconstruct a task's io_uring, I can
> > > certainly do that. We've already spent a few months contemplating on a few
> > > approaches and this turned out to be the best/most powerful. At one point I had
> > > to scrap some my earlier patches completely because they couldn't work with
> > > descriptorless io_uring. Iterator seem like the best solution so far that can
> > > adapt gracefully to feature additions in something seeing as heavy development
> > > as io_uring.
> > >
> > >   [0]: https://github.com/checkpoint-restore/criu/commit/cfa3f405d522334076fc4d687bd077bee3186ccf#diff-d2cfa5a05213c854d539de003a23a286311ae81431026d3d50b0068c0cb5a852
> > >   [1]: https://github.com/checkpoint-restore/criu/pull/1597
> >
> > Is that the main PR? 1095 changed files? Is it stale or something?
> > Is there a way to view the actual logic that exercises these bpf iterators?
>
> No, there is no code exercising BPF iterator in that PR yet (since it wouldn't
> build/run in CI). There's some code I have locally that uses these to collect
> the necessary information, I can post that, either as a sample or selftest in
> the next version, or separately on GH for you to take a look.
>
> I still rebased it so that you can see the rest of the actual code.

I would like to see a working end to end solution.

Also I'd like to hear what Jens and Pavel have to say about
applicability of CRIU to io_uring in general.