[PATCH 3/5] perf/core: Account dropped samples from BPF

[Namhyung Kim <namhyung@kernel.org>]

Like in the software events, the BPF overflow handler can drop samples
by returning 0.  Let's count the dropped samples here too.

Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Song Liu <song@kernel.org>
Cc: Kyle Huey <me@kylehuey.com>
Cc: bpf@vger.kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 kernel/events/core.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 8250e76f63358689..ba1f6b51ea26db5b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -9808,8 +9808,10 @@ static int __perf_event_overflow(struct perf_event *event,
 
 	ret = __perf_event_account_interrupt(event, throttle);
 
-	if (event->prog && !bpf_overflow_handler(event, data, regs))
+	if (event->prog && !bpf_overflow_handler(event, data, regs)) {
+		atomic64_inc(&event->dropped_samples);
 		return ret;
+	}
 
 	/*
 	 * XXX event_limit might not quite work as expected on inherited
-- 
2.46.0.469.g59c65b2a67-goog