[PATCH] latencytop: Remove clear operations from copy_process

[johnnyaiai]

From: johnnyaiai <johnnyaiai@xxxxxxxxxxx>

clear_tsk_latency_tracing will called wheather latencytop_enabled
set or not. this bring unnecessary overhead.

Signed-off-by: johnnyaiai <johnnyaiai@xxxxxxxxxxx>
---
 kernel/latencytop.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/kernel/latencytop.c b/kernel/latencytop.c
index e3acead00..daa65b313 100644
--- a/kernel/latencytop.c
+++ b/kernel/latencytop.c
@@ -63,14 +63,15 @@ static struct latency_record latency_record[MAXLR];
 
 int latencytop_enabled;
 
-void clear_tsk_latency_tracing(struct task_struct *p)
+static void _clear_tsk_latency_tracing(struct task_struct *p)
 {
-	unsigned long flags;
-
-	raw_spin_lock_irqsave(&latency_lock, flags);
 	memset(&p->latency_record, 0, sizeof(p->latency_record));
 	p->latency_record_count = 0;
-	raw_spin_unlock_irqrestore(&latency_lock, flags);
+}
+
+void clear_tsk_latency_tracing(struct task_struct *p)
+{
+	p->latency_record_count = LT_SAVECOUNT + 1;
 }
 
 static void clear_global_latency_tracing(void)
@@ -172,6 +173,9 @@ __account_scheduler_latency(struct task_struct *tsk, int usecs, int inter)
 
 	raw_spin_lock_irqsave(&latency_lock, flags);
 
+	if (unlikely(tsk->latency_record_count == (LT_SAVECOUNT + 1)))
+		_clear_tsk_latency_tracing(tsk);
+
 	account_global_scheduler_latency(tsk, &lat);
 
 	for (i = 0; i < tsk->latency_record_count; i++) {
-- 
2.27.0