linux-kernel - [PATCH RFC 1/3] sched/fair: call __refill_cfs_bandwidth

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Date:	Mon, 16 May 2016 12:36:26 +0300
From:	Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
To:	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org
Cc:	Tejun Heo <tj@...nel.org>, cgroups@...r.kernel.org,
	containers@...ts.linux-foundation.org
Subject: [PATCH RFC 1/3] sched/fair: call __refill_cfs_bandwidth_runtime
 only for finite quota

Both call sites (tg_set_cfs_bandwidth and do_sched_cfs_period_timer)
already have checks for infinite quota.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@...dex-team.ru>
---
 kernel/sched/core.c |    5 +++--
 kernel/sched/fair.c |    6 +-----
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d1f7149f8704..355698188ea9 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8196,10 +8196,11 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
 	cfs_b->period = ns_to_ktime(period);
 	cfs_b->quota = quota;
 
-	__refill_cfs_bandwidth_runtime(cfs_b);
 	/* restart the period timer (if active) to handle new period expiry */
-	if (runtime_enabled)
+	if (runtime_enabled) {
+		__refill_cfs_bandwidth_runtime(cfs_b);
 		start_cfs_bandwidth(cfs_b);
+	}
 	raw_spin_unlock_irq(&cfs_b->lock);
 
 	for_each_online_cpu(i) {
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index e7dd0ec169be..d26b631a9a1d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3559,12 +3559,8 @@ static inline u64 sched_cfs_bandwidth_slice(void)
  */
 void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b)
 {
-	u64 now;
+	u64 now = sched_clock_cpu(smp_processor_id());
 
-	if (cfs_b->quota == RUNTIME_INF)
-		return;
-
-	now = sched_clock_cpu(smp_processor_id());
 	cfs_b->runtime = cfs_b->quota;
 	cfs_b->runtime_expires = now + ktime_to_ns(cfs_b->period);
 }