diff options
Diffstat (limited to 'kernel/sched/MuQSS.c')
| -rw-r--r-- | kernel/sched/MuQSS.c | 55 |
1 files changed, 55 insertions, 0 deletions
diff --git a/kernel/sched/MuQSS.c b/kernel/sched/MuQSS.c index 869626024d56..0f2a72c1917b 100644 --- a/kernel/sched/MuQSS.c +++ b/kernel/sched/MuQSS.c @@ -3608,6 +3608,60 @@ out_resched: rq_unlock(rq); } +#ifdef CONFIG_NO_HZ_FULL +/* + * We can stop the timer tick any time highres timers are active since + * we rely entirely on highres timeouts for task expiry rescheduling. + */ +static void sched_stop_tick(struct rq *rq, int cpu) +{ + if (!hrexpiry_enabled(rq)) + return; + if (!tick_nohz_full_enabled()) + return; + if (!tick_nohz_full_cpu(cpu)) + return; + tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED); +} + +static void sched_start_tick(struct rq *rq, int cpu) +{ + tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED); +} + +/** + * scheduler_tick_max_deferment + * + * Keep at least one tick per second when a single + * active task is running. + * + * This makes sure that uptime continues to move forward, even + * with a very low granularity. + * + * Return: Maximum deferment in nanoseconds. + */ +u64 scheduler_tick_max_deferment(void) +{ + struct rq *rq = this_rq(); + unsigned long next, now = READ_ONCE(jiffies); + + next = rq->last_jiffy + HZ; + + if (time_before_eq(next, now)) + return 0; + + return jiffies_to_nsecs(next - now); +} +#else +static inline void sched_stop_tick(struct rq *rq, int cpu) +{ +} + +static inline void sched_start_tick(struct rq *rq, int cpu) +{ +} +#endif + /* * This function gets called by the timer code, with HZ frequency. * We call it with interrupts disabled. @@ -3628,6 +3682,7 @@ void scheduler_tick(void) rq->last_scheduler_tick = rq->last_jiffy; rq->last_tick = rq->clock; perf_event_task_tick(); + sched_stop_tick(rq, cpu); } #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ |