/* * Initializes rcu mechanism. Assumed to be called early. * That is before local timer(SMP) or jiffie timer (uniproc) is setup. * Note that rcu_qsctr and friends are implicitly * initialized due to the choice of ``0'' for RCU_CTR_INVALID. */ void __init rcu_init(void) { rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long)smp_processor_id()); /* Register notifier for non-boot CPUs */ register_cpu_notifier(&rcu_nb); }
static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self, unsigned long action, void *hcpu) { return rcu_cpu_notify(self, action, hcpu); }
/* * Generic idle loop implementation * * Called with polling cleared. */ static void cpu_idle_loop(void) { while (1) { /* * If the arch has a polling bit, we maintain an invariant: * * Our polling bit is clear if we're not scheduled (i.e. if * rq->curr != rq->idle). This means that, if rq->idle has * the polling bit set, then setting need_resched is * guaranteed to cause the cpu to reschedule. */ __current_set_polling(); quiet_vmstat(); tick_nohz_idle_enter(); while (!need_resched()) { check_pgt_cache(); rmb(); if (cpu_is_offline(smp_processor_id())) { rcu_cpu_notify(NULL, CPU_DYING_IDLE, (void *)(long)smp_processor_id()); smp_mb(); /* all activity before dead. */ this_cpu_write(cpu_dead_idle, true); arch_cpu_idle_dead(); } local_irq_disable(); arch_cpu_idle_enter(); /* * In poll mode we reenable interrupts and spin. * * Also if we detected in the wakeup from idle * path that the tick broadcast device expired * for us, we don't want to go deep idle as we * know that the IPI is going to arrive right * away */ if (cpu_idle_force_poll || tick_check_broadcast_expired()) cpu_idle_poll(); else cpuidle_idle_call(); arch_cpu_idle_exit(); } /* * Since we fell out of the loop above, we know * TIF_NEED_RESCHED must be set, propagate it into * PREEMPT_NEED_RESCHED. * * This is required because for polling idle loops we will * not have had an IPI to fold the state for us. */ preempt_set_need_resched(); tick_nohz_idle_exit(); __current_clr_polling(); /* * We promise to call sched_ttwu_pending and reschedule * if need_resched is set while polling is set. That * means that clearing polling needs to be visible * before doing these things. */ smp_mb__after_atomic(); sched_ttwu_pending(); schedule_preempt_disabled(); } }