From:   Honglei Wang <wanghonglei@didichuxing.com>
To:     Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ben Segall <bsegall@google.com>,
        "Mel Gorman" <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        <linux-kernel@vger.kernel.org>
CC:     Huaixin Chang <changhuaixin@linux.alibaba.com>,
        Honglei Wang <jameshongleiwang@126.com>
Subject: [PATCH v2 1/3] sched/fair: avoid burst statistic if it's not set
Date:   Wed, 8 Dec 2021 22:50:18 +0800
Message-ID: <20211208145018.64657-1-wanghonglei@didichuxing.com>
MIME-Version: 1.0
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Precedence: bulk

It's not necessary to do burst associated statistic and calculation for
runtime if the burst feature is not set at all. Just return at the very
start point if so.

Signed-off-by: Honglei Wang <wanghonglei@didichuxing.com>
---
 kernel/sched/fair.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6e476f6d9435..2cd626c22912 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4640,6 +4640,11 @@ void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
 	if (unlikely(cfs_b->quota == RUNTIME_INF))
 		return;
 
+	if (cfs_b->burst == 0 && cfs_b->runtime_snap == cfs_b->quota) {
+		cfs_b->runtime = cfs_b->quota;
+		return;
+	}
+
 	cfs_b->runtime += cfs_b->quota;
 	runtime = cfs_b->runtime_snap - cfs_b->runtime;
 	if (runtime > 0) {
-- 
2.14.1