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 --- 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)