Re: [PATCH 0/5] bpf: Add user-space-publisher ringbuffer map type

[David Vernet]

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.

Thanks,
David