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From:   Peng Wang <rocking@linux.alibaba.com>
To:     mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com,
        vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
        rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de
Cc:     linux-kernel@vger.kernel.org, Peng Wang <rocking@linux.alibaba.com>
Subject: [PATCH] schied/fair: Skip updating "contrib" without load
Date:   Sat,  7 Dec 2019 00:14:22 +0800
Message-Id: <1575648862-12095-1-git-send-email-rocking@linux.alibaba.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

We only update load_sum/runnable_load_sum/util_sum with
decayed old sum when load is clear.

Signed-off-by: Peng Wang <rocking@linux.alibaba.com>
---
 kernel/sched/pelt.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
index a96db50..4392953 100644
--- a/kernel/sched/pelt.c
+++ b/kernel/sched/pelt.c
@@ -129,8 +129,9 @@ static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3)
 		 * Step 2
 		 */
 		delta %= 1024;
-		contrib = __accumulate_pelt_segments(periods,
-				1024 - sa->period_contrib, delta);
+		if (load)
+			contrib = __accumulate_pelt_segments(periods,
+					1024 - sa->period_contrib, delta);
 	}
 	sa->period_contrib = delta;
 
-- 
1.8.3.1