[patch 24/39] sched: core: Use hrtimer_start[_expires]()

From: Thomas Gleixner
Date: Tue Apr 14 2015 - 17:14:41 EST


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@xxxxxxxxxxxxx>
---
kernel/sched/core.c | 28 ++++++++--------------------
kernel/sched/fair.c | 2 +-
2 files changed, 9 insertions(+), 21 deletions(-)

Index: tip/kernel/sched/core.c
===================================================================
--- tip.orig/kernel/sched/core.c
+++ tip/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);
@@ -352,12 +341,11 @@ static enum hrtimer_restart hrtick(struc

#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);
}

/*
@@ -437,8 +425,8 @@ void hrtick_start(struct rq *rq, u64 del
* 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)
Index: tip/kernel/sched/fair.c
===================================================================
--- tip.orig/kernel/sched/fair.c
+++ tip/kernel/sched/fair.c
@@ -3785,7 +3785,7 @@ static const u64 cfs_bandwidth_slack_per
* 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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