Re: [PATCH] perf/bpf: Don't call bpf_overflow_handler() for tracing events

[Kyle Huey]

On Mon, Jul 15, 2024 at 9:30 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> On Mon, Jul 15, 2024 at 08:19:44AM -0700, Kyle Huey wrote:
>
> > I think this would probably work but stealing the bit seems far more
> > complicated than just gating on perf_event_is_tracing().
>
> perf_event_is_tracing() is something like 3 branches. It is not a simple
> conditional. Combined with that re-load and the wrong return value, this
> all wants a cleanup.
>
> Using that LSB works, it's just that the code aint pretty.

Maybe we could gate on !event->tp_event instead. Somebody who is more
familiar with this code than me should probably confirm that tp_event
being non-null and perf_event_is_tracing() being true are equivalent
though.

- Kyle