diff options
| -rw-r--r-- | kernel/sched.c | 21 | ||||
| -rw-r--r-- | kernel/sched_fair.c | 29 |
2 files changed, 28 insertions, 22 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 4cdc91cf48f6..9e49af00ae3e 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1404,6 +1404,18 @@ void wake_up_idle_cpu(int cpu) smp_send_reschedule(cpu); } +static inline bool got_nohz_idle_kick(void) +{ + return idle_cpu(smp_processor_id()) && this_rq()->nohz_balance_kick; +} + +#else /* CONFIG_NO_HZ */ + +static inline bool got_nohz_idle_kick(void) +{ + return false; +} + #endif /* CONFIG_NO_HZ */ static u64 sched_avg_period(void) @@ -2717,7 +2729,7 @@ static void sched_ttwu_pending(void) void scheduler_ipi(void) { - if (llist_empty(&this_rq()->wake_list)) + if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) return; /* @@ -2735,6 +2747,12 @@ void scheduler_ipi(void) */ irq_enter(); sched_ttwu_pending(); + + /* + * Check if someone kicked us for doing the nohz idle load balance. + */ + if (unlikely(got_nohz_idle_kick() && !need_resched())) + raise_softirq_irqoff(SCHED_SOFTIRQ); irq_exit(); } @@ -8288,7 +8306,6 @@ void __init sched_init(void) rq_attach_root(rq, &def_root_domain); #ifdef CONFIG_NO_HZ rq->nohz_balance_kick = 0; - init_sched_softirq_csd(&per_cpu(remote_sched_softirq_cb, i)); #endif #endif init_rq_hrtick(rq); diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index fef0bfde7c8c..6c5fa1099229 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -4269,22 +4269,6 @@ out_unlock: } #ifdef CONFIG_NO_HZ - -static DEFINE_PER_CPU(struct call_single_data, remote_sched_softirq_cb); - -static void trigger_sched_softirq(void *data) -{ - raise_softirq_irqoff(SCHED_SOFTIRQ); -} - -static inline void init_sched_softirq_csd(struct call_single_data *csd) -{ - csd->func = trigger_sched_softirq; - csd->info = NULL; - csd->flags = 0; - csd->priv = 0; -} - /* * idle load balancing details * - One of the idle CPUs nominates itself as idle load_balancer, while @@ -4450,11 +4434,16 @@ static void nohz_balancer_kick(int cpu) } if (!cpu_rq(ilb_cpu)->nohz_balance_kick) { - struct call_single_data *cp; - cpu_rq(ilb_cpu)->nohz_balance_kick = 1; - cp = &per_cpu(remote_sched_softirq_cb, cpu); - __smp_call_function_single(ilb_cpu, cp, 0); + + smp_mb(); + /* + * Use smp_send_reschedule() instead of resched_cpu(). + * This way we generate a sched IPI on the target cpu which + * is idle. And the softirq performing nohz idle load balance + * will be run before returning from the IPI. + */ + smp_send_reschedule(ilb_cpu); } return; } |