Re: [PATCH 2/2] random: add fork_event sysctl for polling VM forks

Jason A. Donenfeld
2022-05-03T11:55:46Z

On Tue, May 03, 2022 at 10:29:49AM +0200, Lennart Poettering wrote:
> As mentioned earlier, I am not convinced sysctl is the right place for
> this. sysctls are understood by most people as being the place for
> tweaking kernel settings. This is not a kernel setting, but a
> notification concept, and the way Jason defined it there's nothing to
> read nor write, which strongly suggests to move it elsewhere, but not
> /proc/sys/.

I think I'm coming around to this view that having a sysctl return
-ENODATA is weird. It makes `sysctl -a` always complain to stderr, for
example, which seems bad.

> > I can see attractiveness in providing the /run/fork-id directly from the
> > kernel though, to remove the dependency on systemd for poll-less
> > notification of libraries.
>
> I agree.

I'm still not convinced there's value in having a counter or a UUID, but
if you had to choose, would you prefer a counter or a UUID? It sounds
like the former, because you see a use for distinguishing between zero
and non-zero? Or did you finally agree with me that vmgenid isn't
granular enough for that?

Jason