void __init sched_init(void)
{
	int i, j;
	unsigned long alloc_size = 0, ptr;

#ifdef CONFIG_FAIR_GROUP_SCHED
	alloc_size += 2 * nr_cpu_ids * sizeof(void **);
#endif
#ifdef CONFIG_RT_GROUP_SCHED
	alloc_size += 2 * nr_cpu_ids * sizeof(void **);
#endif
	if (alloc_size) {
		ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT);

#ifdef CONFIG_FAIR_GROUP_SCHED
		root_task_group.se = (struct sched_entity **)ptr;
		ptr += nr_cpu_ids * sizeof(void **);

		root_task_group.cfs_rq = (struct cfs_rq **)ptr;
		ptr += nr_cpu_ids * sizeof(void **);

#endif /* CONFIG_FAIR_GROUP_SCHED */
#ifdef CONFIG_RT_GROUP_SCHED
		root_task_group.rt_se = (struct sched_rt_entity **)ptr;
		ptr += nr_cpu_ids * sizeof(void **);

		root_task_group.rt_rq = (struct rt_rq **)ptr;
		ptr += nr_cpu_ids * sizeof(void **);

#endif /* CONFIG_RT_GROUP_SCHED */
	}
#ifdef CONFIG_CPUMASK_OFFSTACK
	for_each_possible_cpu(i) {
		per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node(
			cpumask_size(), GFP_KERNEL, cpu_to_node(i));
	}
#endif /* CONFIG_CPUMASK_OFFSTACK */

	init_rt_bandwidth(&def_rt_bandwidth,
			global_rt_period(), global_rt_runtime());
	init_dl_bandwidth(&def_dl_bandwidth,
			global_rt_period(), global_rt_runtime());

#ifdef CONFIG_SMP
	init_defrootdomain();
#endif

#ifdef CONFIG_RT_GROUP_SCHED
	init_rt_bandwidth(&root_task_group.rt_bandwidth,
			global_rt_period(), global_rt_runtime());
#endif /* CONFIG_RT_GROUP_SCHED */

#ifdef CONFIG_CGROUP_SCHED
	task_group_cache = KMEM_CACHE(task_group, 0);

	list_add(&root_task_group.list, &task_groups);
	INIT_LIST_HEAD(&root_task_group.children);
	INIT_LIST_HEAD(&root_task_group.siblings);
	autogroup_init(&init_task);
#endif /* CONFIG_CGROUP_SCHED */

	for_each_possible_cpu(i) {
		struct rq *rq;

		rq = cpu_rq(i);
		raw_spin_lock_init(&rq->lock);
		rq->nr_running = 0;
		rq->calc_load_active = 0;
		rq->calc_load_update = jiffies + LOAD_FREQ;
		init_cfs_rq(&rq->cfs);
		init_rt_rq(&rq->rt);
		init_dl_rq(&rq->dl);
#ifdef CONFIG_FAIR_GROUP_SCHED
		root_task_group.shares = ROOT_TASK_GROUP_LOAD;
		INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
		/*
		 * How much cpu bandwidth does root_task_group get?
		 *
		 * In case of task-groups formed thr' the cgroup filesystem, it
		 * gets 100% of the cpu resources in the system. This overall
		 * system cpu resource is divided among the tasks of
		 * root_task_group and its child task-groups in a fair manner,
		 * based on each entity's (task or task-group's) weight
		 * (se->load.weight).
		 *
		 * In other words, if root_task_group has 10 tasks of weight
		 * 1024) and two child groups A0 and A1 (of weight 1024 each),
		 * then A0's share of the cpu resource is:
		 *
		 *	A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
		 *
		 * We achieve this by letting root_task_group's tasks sit
		 * directly in rq->cfs (i.e root_task_group->se[] = NULL).
		 */
		init_cfs_bandwidth(&root_task_group.cfs_bandwidth);
		init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL);
#endif /* CONFIG_FAIR_GROUP_SCHED */

		rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
#ifdef CONFIG_RT_GROUP_SCHED
		init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL);
#endif

		for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
			rq->cpu_load[j] = 0;

		rq->last_load_update_tick = jiffies;

#ifdef CONFIG_SMP
		rq->sd = NULL;
		rq->rd = NULL;
		rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE;
		rq->balance_callback = NULL;
		rq->active_balance = 0;
		rq->next_balance = jiffies;
		rq->push_cpu = 0;
		rq->cpu = i;
		rq->online = 0;
		rq->idle_stamp = 0;
		rq->avg_idle = 2*sysctl_sched_migration_cost;
		rq->max_idle_balance_cost = sysctl_sched_migration_cost;

		INIT_LIST_HEAD(&rq->cfs_tasks);

		rq_attach_root(rq, &def_root_domain);
#ifdef CONFIG_NO_HZ_COMMON
		rq->nohz_flags = 0;
#endif
#ifdef CONFIG_NO_HZ_FULL
		rq->last_sched_tick = 0;
#endif
#endif
		init_rq_hrtick(rq);
		atomic_set(&rq->nr_iowait, 0);
	}

	set_load_weight(&init_task);

#ifdef CONFIG_PREEMPT_NOTIFIERS
	INIT_HLIST_HEAD(&init_task.preempt_notifiers);
#endif

	/*
	 * The boot idle thread does lazy MMU switching as well:
	 */
	atomic_inc(&init_mm.mm_count);
	enter_lazy_tlb(&init_mm, current);

	/*
	 * During early bootup we pretend to be a normal task:
	 */
	current->sched_class = &fair_sched_class;

	/*
	 * Make us the idle thread. Technically, schedule() should not be
	 * called from this thread, however somewhere below it might be,
	 * but because we are the idle thread, we just pick up running again
	 * when this runqueue becomes "idle".
	 */
	init_idle(current, smp_processor_id());

	calc_load_update = jiffies + LOAD_FREQ;

#ifdef CONFIG_SMP
	zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
	/* May be allocated at isolcpus cmdline parse time */
	if (cpu_isolated_map == NULL)
		zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
	idle_thread_set_boot_cpu();
	set_cpu_rq_start_time();
#endif
	init_sched_fair_class();

	scheduler_running = 1;
}