linux-kernel - [tip:timers/core] sched: core: Use hrtimer_start[

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Date:	Wed, 22 Apr 2015 12:11:20 -0700
From:	tip-bot for Thomas Gleixner <tipbot@...or.com>
To:	linux-tip-commits@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org, preeti@...ux.vnet.ibm.com,
	hpa@...or.com, peterz@...radead.org, viresh.kumar@...aro.org,
	mingo@...nel.org, fweisbec@...il.com, tglx@...utronix.de,
	mtosatti@...hat.com
Subject: [tip:timers/core] sched: core: Use hrtimer_start[_expires]()

Commit-ID:  4961b6e11825c2b05b516374b1800fc5dfc2cb78
Gitweb:     http://git.kernel.org/tip/4961b6e11825c2b05b516374b1800fc5dfc2cb78
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Tue, 14 Apr 2015 21:09:05 +0000
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Wed, 22 Apr 2015 17:06:51 +0200

sched: core: Use hrtimer_start[_expires]()

hrtimer_start() now enforces a timer interrupt when an already expired
timer is enqueued.

Get rid of the __hrtimer_start_range_ns() invocations and the loops
around it.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Acked-by: Peter Zijlstra <peterz@...radead.org>
Cc: Preeti U Murthy <preeti@...ux.vnet.ibm.com>
Cc: Viresh Kumar <viresh.kumar@...aro.org>
Cc: Marcelo Tosatti <mtosatti@...hat.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Link: http://lkml.kernel.org/r/20150414203502.531131739@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 kernel/sched/core.c | 28 ++++++++--------------------
 kernel/sched/fair.c |  2 +-
 2 files changed, 9 insertions(+), 21 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index f9123a8..3026678 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -92,22 +92,11 @@
 
 void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period)
 {
-	unsigned long delta;
-	ktime_t soft, hard, now;
-
-	for (;;) {
-		if (hrtimer_active(period_timer))
-			break;
-
-		now = hrtimer_cb_get_time(period_timer);
-		hrtimer_forward(period_timer, now, period);
+	if (hrtimer_active(period_timer))
+		return;
 
-		soft = hrtimer_get_softexpires(period_timer);
-		hard = hrtimer_get_expires(period_timer);
-		delta = ktime_to_ns(ktime_sub(hard, soft));
-		__hrtimer_start_range_ns(period_timer, soft, delta,
-					 HRTIMER_MODE_ABS_PINNED, 0);
-	}
+	hrtimer_forward_now(period_timer, period);
+	hrtimer_start_expires(period_timer, HRTIMER_MODE_ABS_PINNED);
 }
 
 DEFINE_MUTEX(sched_domains_mutex);
@@ -355,12 +344,11 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer)
 
 #ifdef CONFIG_SMP
 
-static int __hrtick_restart(struct rq *rq)
+static void __hrtick_restart(struct rq *rq)
 {
 	struct hrtimer *timer = &rq->hrtick_timer;
-	ktime_t time = hrtimer_get_softexpires(timer);
 
-	return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0);
+	hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED);
 }
 
 /*
@@ -440,8 +428,8 @@ void hrtick_start(struct rq *rq, u64 delay)
 	 * doesn't make sense. Rely on vruntime for fairness.
 	 */
 	delay = max_t(u64, delay, 10000LL);
-	__hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
-			HRTIMER_MODE_REL_PINNED, 0);
+	hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
+		      HRTIMER_MODE_REL_PINNED);
 }
 
 static inline void init_hrtick(void)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index ffeaa41..854881b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -3850,7 +3850,7 @@ static const u64 cfs_bandwidth_slack_period = 5 * NSEC_PER_MSEC;
  * Are we near the end of the current quota period?
  *
  * Requires cfs_b->lock for hrtimer_expires_remaining to be safe against the
- * hrtimer base being cleared by __hrtimer_start_range_ns. In the case of
+ * hrtimer base being cleared by hrtimer_start. In the case of
  * migrate_hrtimers, base is never cleared, so we are fine.
  */
 static int runtime_refresh_within(struct cfs_bandwidth *cfs_b, u64 min_expire)
--
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