Re: [PATCH 0/3] block: blk_interposer - Block Layer Interposer

[Hannes Reinecke]

On 12/15/20 7:51 AM, Bob Liu wrote:
> Hi Folks,
>
> On 12/12/20 12:56 AM, Hannes Reinecke wrote:
> > On 12/11/20 5:33 PM, Jens Axboe wrote:
> > > On 12/11/20 9:30 AM, Mike Snitzer wrote:
> > > > While I still think there needs to be a proper _upstream_ consumer of
> > > > blk_interposer as a condition of it going in.. I'll let others make the
> > > > call.
> > >
> > > That's an unequivocal rule.
> > >
> > > > As such, I'll defer to Jens, Christoph and others on whether your
> > > > minimalist blk_interposer hook is acceptable in the near-term.
> > >
> > > I don't think so, we don't do short term bandaids just to plan on
> > > ripping that out when the real functionality is there. IMHO, the dm
> > > approach is the way to go - it provides exactly the functionality that
> > > is needed in an appropriate way, instead of hacking some "interposer"
> > > into the core block layer.
> > Which is my plan, too.
> >
> > I'll be working with the Veeam folks to present a joint patchset (including the DM bits) for the next round.
>
> Besides the dm approach, do you think Veeam's original requirement is a good
> use case of "block/bpf: add eBPF based block layer IO filtering"?
> https://lwn.net/ml/bpf/20200812163305.545447-1-leah.rumancik@xxxxxxxxx/
That would actually a really cool use-case.
You could also consider a XDP-like functionality for eBPF, to move 
individual requests from one queue to the other; DM on steroids :-)

Should I try to include that patchset?

Cheers,

Hannes
--
Dr. Hannes Reinecke                Kernel Storage Architect
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