linux-kernel - Re: [PATCH v3 1/4] perf/bpf: Call bpf handler directly, not through overflow machinery

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Message-ID: <CAPhsuW6VqD=zie6Y6JPALp3egMSYWF6UysS+bQG_61t=6v4fxQ@mail.gmail.com>
Date: Tue, 2 Jan 2024 14:56:03 -0800
From: Song Liu <song@...nel.org>
To: Kyle Huey <me@...ehuey.com>
Cc: Kyle Huey <khuey@...ehuey.com>, linux-kernel@...r.kernel.org, 
	Andrii Nakryiko <andrii.nakryiko@...il.com>, Jiri Olsa <jolsa@...nel.org>, 
	Namhyung Kim <namhyung@...nel.org>, Marco Elver <elver@...gle.com>, 
	Yonghong Song <yonghong.song@...ux.dev>, "Robert O'Callahan" <robert@...llahan.org>, 
	Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Ian Rogers <irogers@...gle.com>, 
	Adrian Hunter <adrian.hunter@...el.com>, linux-perf-users@...r.kernel.org, 
	bpf@...r.kernel.org
Subject: Re: [PATCH v3 1/4] perf/bpf: Call bpf handler directly, not through
 overflow machinery

On Sun, Dec 10, 2023 at 8:55 PM Kyle Huey <me@...ehuey.com> wrote:
>
> To ultimately allow bpf programs attached to perf events to completely
> suppress all of the effects of a perf event overflow (rather than just the
> sample output, as they do today), call bpf_overflow_handler() from
> __perf_event_overflow() directly rather than modifying struct perf_event's
> overflow_handler. Return the bpf program's return value from
> bpf_overflow_handler() so that __perf_event_overflow() knows how to
> proceed. Remove the now unnecessary orig_overflow_handler from struct
> perf_event.
>
> This patch is solely a refactoring and results in no behavior change.
>
> Signed-off-by: Kyle Huey <khuey@...ehuey.com>
> Suggested-by: Namhyung Kim <namhyung@...nel.org>

Acked-by: Song Liu <song@...nel.org>