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Date:   Tue, 16 Aug 2022 16:39:59 -0500
From:   David Vernet <void@manifault.com>
To:     Hao Luo <haoluo@google.com>
Cc:     bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
        andrii@kernel.org, john.fastabend@gmail.com, martin.lau@linux.dev,
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        jolsa@kernel.org, tj@kernel.org, joannelkoong@gmail.com,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/5] bpf: Add user-space-publisher ringbuffer map type
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On Tue, Aug 16, 2022 at 10:01:38AM -0700, Hao Luo wrote:
> On Tue, Aug 16, 2022 at 8:10 AM David Vernet <void@manifault.com> wrote:
> >
> > On Mon, Aug 15, 2022 at 02:13:13PM -0700, Hao Luo wrote:
> > > >
> > > > Iters allow userspace to kick the kernel, but IMO they're meant to enable
> > > > data extraction from the kernel, and dumping kernel data into user-space.
> > >
> > > Not necessarily extracting data and dumping data. It could be used to
> > > do operations on a set of objects, the operation could be
> > > notification. Iterating and notifying are orthogonal IMHO.
> > >
> > > > What I'm proposing is a more generalizable way of driving logic in the
> > > > kernel from user-space.
> > > > Does that make sense? Looking forward to hearing your thoughts.
> > >
> > > Yes, sort of. I see the difference between iter and the proposed
> > > interface. But I am not clear about the motivation of a new APis for
> > > kicking callbacks from userspace. I guess maybe it will become clear,
> > > when you publish a concerte RFC of that interface and integrates with
> > > your userspace publisher.
> >
> > Fair enough -- let me remove this from the cover letter in future
> > versions of the patch-set. To your point, there's probably little to be
> > gained in debating the merits of adding such APIs until there's a
> > concrete use-case.
> >
> 
> Yep, sounds good. I don't mean to debate :) I would like to help. If
> we could build on top of existing infra and make improvements, IMHO it
> would be easier to maintain. Anyway, I'm looking forward to your
> proposed APIs.

Don't worry, I did not take it that you were debating. I very much
appreciate your thoughts and help. If and when I send out that RFC
patchset, I'll be sure to cc you (if not reach out beforehand as well to
discuss).