linux-kernel - [PATCH 3/4] perf: Add perf_event_overflow

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Date:   Wed, 28 Dec 2016 14:31:05 +0100
From:   Jiri Olsa <jolsa@...nel.org>
To:     Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Andi Kleen <andi@...stfloor.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Vince Weaver <vince@...ter.net>
Subject: [PATCH 3/4] perf: Add perf_event_overflow_throttle function

Adding perf_event_overflow_throttle function to allow
callers to decide on throttling events. It's used in
following patch.

Signed-off-by: Jiri Olsa <jolsa@...nel.org>
---
 include/linux/perf_event.h |  4 ++++
 kernel/events/core.c       | 14 +++++++-------
 2 files changed, 11 insertions(+), 7 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 78ed8105e64d..f5a9468bad90 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -966,6 +966,10 @@ extern int perf_event_overflow(struct perf_event *event,
 				 struct perf_sample_data *data,
 				 struct pt_regs *regs);
 
+extern int perf_event_overflow_throttle(struct perf_event *event,
+					int throttle, struct perf_sample_data *data,
+					struct pt_regs *regs);
+
 extern void perf_event_output_forward(struct perf_event *event,
 				     struct perf_sample_data *data,
 				     struct pt_regs *regs);
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 38f4baef5df5..466ed56340bc 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7079,9 +7079,9 @@ int perf_event_account_interrupt(struct perf_event *event)
  * Generic event overflow handling, sampling.
  */
 
-static int __perf_event_overflow(struct perf_event *event,
-				   int throttle, struct perf_sample_data *data,
-				   struct pt_regs *regs)
+int perf_event_overflow_throttle(struct perf_event *event,
+				 int throttle, struct perf_sample_data *data,
+				 struct pt_regs *regs)
 {
 	int events = atomic_read(&event->event_limit);
 	int ret = 0;
@@ -7122,7 +7122,7 @@ int perf_event_overflow(struct perf_event *event,
 			  struct perf_sample_data *data,
 			  struct pt_regs *regs)
 {
-	return __perf_event_overflow(event, 1, data, regs);
+	return perf_event_overflow_throttle(event, 1, data, regs);
 }
 
 /*
@@ -7184,8 +7184,8 @@ static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
 		return;
 
 	for (; overflow; overflow--) {
-		if (__perf_event_overflow(event, throttle,
-					    data, regs)) {
+		if (perf_event_overflow_throttle(event, throttle,
+						 data, regs)) {
 			/*
 			 * We inhibit the overflow from happening when
 			 * hwc->interrupts == MAX_INTERRUPTS.
@@ -8298,7 +8298,7 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
 
 	if (regs && !perf_exclude_event(event, regs)) {
 		if (!(event->attr.exclude_idle && is_idle_task(current)))
-			if (__perf_event_overflow(event, 1, &data, regs))
+			if (perf_event_overflow_throttle(event, 1, &data, regs))
 				ret = HRTIMER_NORESTART;
 	}
 
-- 
2.7.4