Re: [RFC PATCH 00/20] rv: Add support for BPF monitors

[Tomas Glozar]

On Thu, Sep 3, 2026 at 4:03 AM Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> I don't think bpf fits here. I haven't seen active use of RV and even less
> so of any request from people who want this kind of programmability.
>
> So Nack for now. Sorry.
>

A major application of RV is monitoring the combined behavior of the
kernel and an external application, see [1] [2]. Adopting RV for these
use cases is difficult because the monitors are currently built into
the kernel. Blocking BPF adoption because it is not widely used risks
a deadlock: RV not getting enough users, because it cannot use BPF,
and BPF rejecting RV because it lacks sufficient use.

Of course, I might be entirely wrong: RV may not end up being
interesting enough to users even with the BPF hooks in place, or it
might grow enough with only in-kernel monitors for you to take it
seriously. However, we cannot predict that in advance.

(Note also that the idea to use BPF in RV dates back to 2022 [3].)

[1] https://lore.kernel.org/linux-trace-kernel/20260827072400.45734-1-tobias.schaffner@xxxxxxxxxxx/T/#e8a8b21136a60ad7c8f67b07c66f71de0ec0c1075
[2] https://docs.kernel.org/trace/rv/monitor_rtapp.html
[3] https://gitlab.com/linux-rv-tools/dot2bpf

Tomas