sched/core: Rewrite and improve select_idle_siblings()

[cascardo/linux.git] / kernel / sched / sched.h

#include <linux/sched.h>
#include <linux/sched/sysctl.h>
#include <linux/sched/rt.h>
#include <linux/sched/deadline.h>
#include <linux/binfmts.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
#include <linux/stop_machine.h>
#include <linux/irq_work.h>
#include <linux/tick.h>
#include <linux/slab.h>

#include "cpupri.h"
#include "cpudeadline.h"
#include "cpuacct.h"

struct rq;
struct cpuidle_state;

/* task_struct::on_rq states: */
#define TASK_ON_RQ_QUEUED       1
#define TASK_ON_RQ_MIGRATING    2

extern __read_mostly int scheduler_running;

extern unsigned long calc_load_update;
extern atomic_long_t calc_load_tasks;

extern void calc_global_load_tick(struct rq *this_rq);
extern long calc_load_fold_active(struct rq *this_rq, long adjust);

#ifdef CONFIG_SMP
extern void cpu_load_update_active(struct rq *this_rq);
#else
static inline void cpu_load_update_active(struct rq *this_rq) { }
#endif

#ifdef CONFIG_SCHED_SMT
extern void update_idle_core(struct rq *rq);
#else
static inline void update_idle_core(struct rq *rq) { }
#endif

/*
 * Helpers for converting nanosecond timing to jiffy resolution
 */
#define NS_TO_JIFFIES(TIME)     ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))

/*
 * Increase resolution of nice-level calculations for 64-bit architectures.
 * The extra resolution improves shares distribution and load balancing of
 * low-weight task groups (eg. nice +19 on an autogroup), deeper taskgroup
 * hierarchies, especially on larger systems. This is not a user-visible change
 * and does not change the user-interface for setting shares/weights.
 *
 * We increase resolution only if we have enough bits to allow this increased
 * resolution (i.e. 64bit). The costs for increasing resolution when 32bit are
 * pretty high and the returns do not justify the increased costs.
 *
 * Really only required when CONFIG_FAIR_GROUP_SCHED is also set, but to
 * increase coverage and consistency always enable it on 64bit platforms.
 */
#ifdef CONFIG_64BIT
# define NICE_0_LOAD_SHIFT      (SCHED_FIXEDPOINT_SHIFT + SCHED_FIXEDPOINT_SHIFT)
# define scale_load(w)          ((w) << SCHED_FIXEDPOINT_SHIFT)
# define scale_load_down(w)     ((w) >> SCHED_FIXEDPOINT_SHIFT)
#else
# define NICE_0_LOAD_SHIFT      (SCHED_FIXEDPOINT_SHIFT)
# define scale_load(w)          (w)
# define scale_load_down(w)     (w)
#endif

/*
 * Task weight (visible to users) and its load (invisible to users) have
 * independent resolution, but they should be well calibrated. We use
 * scale_load() and scale_load_down(w) to convert between them. The
 * following must be true:
 *
 *  scale_load(sched_prio_to_weight[USER_PRIO(NICE_TO_PRIO(0))]) == NICE_0_LOAD
 *
 */
#define NICE_0_LOAD             (1L << NICE_0_LOAD_SHIFT)

/*
 * Single value that decides SCHED_DEADLINE internal math precision.
 * 10 -> just above 1us
 * 9  -> just above 0.5us
 */
#define DL_SCALE (10)

/*
 * These are the 'tuning knobs' of the scheduler:
 */

/*
 * single value that denotes runtime == period, ie unlimited time.
 */
#define RUNTIME_INF     ((u64)~0ULL)

static inline int idle_policy(int policy)
{
        return policy == SCHED_IDLE;
}
static inline int fair_policy(int policy)
{
        return policy == SCHED_NORMAL || policy == SCHED_BATCH;
}

static inline int rt_policy(int policy)
{
        return policy == SCHED_FIFO || policy == SCHED_RR;
}

static inline int dl_policy(int policy)
{
        return policy == SCHED_DEADLINE;
}
static inline bool valid_policy(int policy)
{
        return idle_policy(policy) || fair_policy(policy) ||
                rt_policy(policy) || dl_policy(policy);
}

static inline int task_has_rt_policy(struct task_struct *p)
{
        return rt_policy(p->policy);
}

static inline int task_has_dl_policy(struct task_struct *p)
{
        return dl_policy(p->policy);
}

/*
 * Tells if entity @a should preempt entity @b.
 */
static inline bool
dl_entity_preempt(struct sched_dl_entity *a, struct sched_dl_entity *b)
{
        return dl_time_before(a->deadline, b->deadline);
}

/*
 * This is the priority-queue data structure of the RT scheduling class:
 */
struct rt_prio_array {
        DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
        struct list_head queue[MAX_RT_PRIO];
};

struct rt_bandwidth {
        /* nests inside the rq lock: */
        raw_spinlock_t          rt_runtime_lock;
        ktime_t                 rt_period;
        u64                     rt_runtime;
        struct hrtimer          rt_period_timer;
        unsigned int            rt_period_active;
};

void __dl_clear_params(struct task_struct *p);

/*
 * To keep the bandwidth of -deadline tasks and groups under control
 * we need some place where:
 *  - store the maximum -deadline bandwidth of the system (the group);
 *  - cache the fraction of that bandwidth that is currently allocated.
 *
 * This is all done in the data structure below. It is similar to the
 * one used for RT-throttling (rt_bandwidth), with the main difference
 * that, since here we are only interested in admission control, we
 * do not decrease any runtime while the group "executes", neither we
 * need a timer to replenish it.
 *
 * With respect to SMP, the bandwidth is given on a per-CPU basis,
 * meaning that:
 *  - dl_bw (< 100%) is the bandwidth of the system (group) on each CPU;
 *  - dl_total_bw array contains, in the i-eth element, the currently
 *    allocated bandwidth on the i-eth CPU.
 * Moreover, groups consume bandwidth on each CPU, while tasks only
 * consume bandwidth on the CPU they're running on.
 * Finally, dl_total_bw_cpu is used to cache the index of dl_total_bw
 * that will be shown the next time the proc or cgroup controls will
 * be red. It on its turn can be changed by writing on its own
 * control.
 */
struct dl_bandwidth {
        raw_spinlock_t dl_runtime_lock;
        u64 dl_runtime;
        u64 dl_period;
};

static inline int dl_bandwidth_enabled(void)
{
        return sysctl_sched_rt_runtime >= 0;
}

extern struct dl_bw *dl_bw_of(int i);

struct dl_bw {
        raw_spinlock_t lock;
        u64 bw, total_bw;
};

static inline
void __dl_clear(struct dl_bw *dl_b, u64 tsk_bw)
{
        dl_b->total_bw -= tsk_bw;
}

static inline
void __dl_add(struct dl_bw *dl_b, u64 tsk_bw)
{
        dl_b->total_bw += tsk_bw;
}

static inline
bool __dl_overflow(struct dl_bw *dl_b, int cpus, u64 old_bw, u64 new_bw)
{
        return dl_b->bw != -1 &&
               dl_b->bw * cpus < dl_b->total_bw - old_bw + new_bw;
}

extern struct mutex sched_domains_mutex;

#ifdef CONFIG_CGROUP_SCHED

#include <linux/cgroup.h>

struct cfs_rq;
struct rt_rq;

extern struct list_head task_groups;

struct cfs_bandwidth {
#ifdef CONFIG_CFS_BANDWIDTH
        raw_spinlock_t lock;
        ktime_t period;
        u64 quota, runtime;
        s64 hierarchical_quota;
        u64 runtime_expires;

        int idle, period_active;
        struct hrtimer period_timer, slack_timer;
        struct list_head throttled_cfs_rq;

        /* statistics */
        int nr_periods, nr_throttled;
        u64 throttled_time;
#endif
};

/* task group related information */
struct task_group {
        struct cgroup_subsys_state css;

#ifdef CONFIG_FAIR_GROUP_SCHED
        /* schedulable entities of this group on each cpu */
        struct sched_entity **se;
        /* runqueue "owned" by this group on each cpu */
        struct cfs_rq **cfs_rq;
        unsigned long shares;

#ifdef  CONFIG_SMP
        /*
         * load_avg can be heavily contended at clock tick time, so put
         * it in its own cacheline separated from the fields above which
         * will also be accessed at each tick.
         */
        atomic_long_t load_avg ____cacheline_aligned;
#endif
#endif

#ifdef CONFIG_RT_GROUP_SCHED
        struct sched_rt_entity **rt_se;
        struct rt_rq **rt_rq;

        struct rt_bandwidth rt_bandwidth;
#endif

        struct rcu_head rcu;
        struct list_head list;

        struct task_group *parent;
        struct list_head siblings;
        struct list_head children;

#ifdef CONFIG_SCHED_AUTOGROUP
        struct autogroup *autogroup;
#endif

        struct cfs_bandwidth cfs_bandwidth;
};

#ifdef CONFIG_FAIR_GROUP_SCHED
#define ROOT_TASK_GROUP_LOAD    NICE_0_LOAD

/*
 * A weight of 0 or 1 can cause arithmetics problems.
 * A weight of a cfs_rq is the sum of weights of which entities
 * are queued on this cfs_rq, so a weight of a entity should not be
 * too large, so as the shares value of a task group.
 * (The default weight is 1024 - so there's no practical
 *  limitation from this.)
 */
#define MIN_SHARES      (1UL <<  1)
#define MAX_SHARES      (1UL << 18)
#endif

typedef int (*tg_visitor)(struct task_group *, void *);

extern int walk_tg_tree_from(struct task_group *from,
                             tg_visitor down, tg_visitor up, void *data);

/*
 * Iterate the full tree, calling @down when first entering a node and @up when
 * leaving it for the final time.
 *
 * Caller must hold rcu_lock or sufficient equivalent.
 */
static inline int walk_tg_tree(tg_visitor down, tg_visitor up, void *data)
{
        return walk_tg_tree_from(&root_task_group, down, up, data);
}

extern int tg_nop(struct task_group *tg, void *data);

extern void free_fair_sched_group(struct task_group *tg);
extern int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent);
extern void online_fair_sched_group(struct task_group *tg);
extern void unregister_fair_sched_group(struct task_group *tg);
extern void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
                        struct sched_entity *se, int cpu,
                        struct sched_entity *parent);
extern void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b);

extern void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b);
extern void start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);

extern void free_rt_sched_group(struct task_group *tg);
extern int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent);
extern void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
                struct sched_rt_entity *rt_se, int cpu,
                struct sched_rt_entity *parent);

extern struct task_group *sched_create_group(struct task_group *parent);
extern void sched_online_group(struct task_group *tg,
                               struct task_group *parent);
extern void sched_destroy_group(struct task_group *tg);
extern void sched_offline_group(struct task_group *tg);

extern void sched_move_task(struct task_struct *tsk);

#ifdef CONFIG_FAIR_GROUP_SCHED
extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);

#ifdef CONFIG_SMP
extern void set_task_rq_fair(struct sched_entity *se,
                             struct cfs_rq *prev, struct cfs_rq *next);
#else /* !CONFIG_SMP */
static inline void set_task_rq_fair(struct sched_entity *se,
                             struct cfs_rq *prev, struct cfs_rq *next) { }
#endif /* CONFIG_SMP */
#endif /* CONFIG_FAIR_GROUP_SCHED */

#else /* CONFIG_CGROUP_SCHED */

struct cfs_bandwidth { };

#endif  /* CONFIG_CGROUP_SCHED */

/* CFS-related fields in a runqueue */
struct cfs_rq {
        struct load_weight load;
        unsigned int nr_running, h_nr_running;

        u64 exec_clock;
        u64 min_vruntime;
#ifndef CONFIG_64BIT
        u64 min_vruntime_copy;
#endif

        struct rb_root tasks_timeline;
        struct rb_node *rb_leftmost;

        /*
         * 'curr' points to currently running entity on this cfs_rq.
         * It is set to NULL otherwise (i.e when none are currently running).
         */
        struct sched_entity *curr, *next, *last, *skip;

#ifdef  CONFIG_SCHED_DEBUG
        unsigned int nr_spread_over;
#endif

#ifdef CONFIG_SMP
        /*
         * CFS load tracking
         */
        struct sched_avg avg;
        u64 runnable_load_sum;
        unsigned long runnable_load_avg;
#ifdef CONFIG_FAIR_GROUP_SCHED
        unsigned long tg_load_avg_contrib;
#endif
        atomic_long_t removed_load_avg, removed_util_avg;
#ifndef CONFIG_64BIT
        u64 load_last_update_time_copy;
#endif

#ifdef CONFIG_FAIR_GROUP_SCHED
        /*
         *   h_load = weight * f(tg)
         *
         * Where f(tg) is the recursive weight fraction assigned to
         * this group.
         */
        unsigned long h_load;
        u64 last_h_load_update;
        struct sched_entity *h_load_next;
#endif /* CONFIG_FAIR_GROUP_SCHED */
#endif /* CONFIG_SMP */

#ifdef CONFIG_FAIR_GROUP_SCHED
        struct rq *rq;  /* cpu runqueue to which this cfs_rq is attached */

        /*
         * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
         * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
         * (like users, containers etc.)
         *
         * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
         * list is used during load balance.
         */
        int on_list;
        struct list_head leaf_cfs_rq_list;
        struct task_group *tg;  /* group that "owns" this runqueue */

#ifdef CONFIG_CFS_BANDWIDTH
        int runtime_enabled;
        u64 runtime_expires;
        s64 runtime_remaining;

        u64 throttled_clock, throttled_clock_task;
        u64 throttled_clock_task_time;
        int throttled, throttle_count;
        struct list_head throttled_list;
#endif /* CONFIG_CFS_BANDWIDTH */
#endif /* CONFIG_FAIR_GROUP_SCHED */
};

static inline int rt_bandwidth_enabled(void)
{
        return sysctl_sched_rt_runtime >= 0;
}

/* RT IPI pull logic requires IRQ_WORK */
#ifdef CONFIG_IRQ_WORK
# define HAVE_RT_PUSH_IPI
#endif

/* Real-Time classes' related field in a runqueue: */
struct rt_rq {
        struct rt_prio_array active;
        unsigned int rt_nr_running;
        unsigned int rr_nr_running;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
        struct {
                int curr; /* highest queued rt task prio */
#ifdef CONFIG_SMP
                int next; /* next highest */
#endif
        } highest_prio;
#endif
#ifdef CONFIG_SMP
        unsigned long rt_nr_migratory;
        unsigned long rt_nr_total;
        int overloaded;
        struct plist_head pushable_tasks;
#ifdef HAVE_RT_PUSH_IPI
        int push_flags;
        int push_cpu;
        struct irq_work push_work;
        raw_spinlock_t push_lock;
#endif
#endif /* CONFIG_SMP */
        int rt_queued;

        int rt_throttled;
        u64 rt_time;
        u64 rt_runtime;
        /* Nests inside the rq lock: */
        raw_spinlock_t rt_runtime_lock;

#ifdef CONFIG_RT_GROUP_SCHED
        unsigned long rt_nr_boosted;

        struct rq *rq;
        struct task_group *tg;
#endif
};

/* Deadline class' related fields in a runqueue */
struct dl_rq {
        /* runqueue is an rbtree, ordered by deadline */
        struct rb_root rb_root;
        struct rb_node *rb_leftmost;

        unsigned long dl_nr_running;

#ifdef CONFIG_SMP
        /*
         * Deadline values of the currently executing and the
         * earliest ready task on this rq. Caching these facilitates
         * the decision wether or not a ready but not running task
         * should migrate somewhere else.
         */
        struct {
                u64 curr;
                u64 next;
        } earliest_dl;

        unsigned long dl_nr_migratory;
        int overloaded;

        /*
         * Tasks on this rq that can be pushed away. They are kept in
         * an rb-tree, ordered by tasks' deadlines, with caching
         * of the leftmost (earliest deadline) element.
         */
        struct rb_root pushable_dl_tasks_root;
        struct rb_node *pushable_dl_tasks_leftmost;
#else
        struct dl_bw dl_bw;
#endif
};

#ifdef CONFIG_SMP

/*
 * We add the notion of a root-domain which will be used to define per-domain
 * variables. Each exclusive cpuset essentially defines an island domain by
 * fully partitioning the member cpus from any other cpuset. Whenever a new
 * exclusive cpuset is created, we also create and attach a new root-domain
 * object.
 *
 */
struct root_domain {
        atomic_t refcount;
        atomic_t rto_count;
        struct rcu_head rcu;
        cpumask_var_t span;
        cpumask_var_t online;

        /* Indicate more than one runnable task for any CPU */
        bool overload;

        /*
         * The bit corresponding to a CPU gets set here if such CPU has more
         * than one runnable -deadline task (as it is below for RT tasks).
         */
        cpumask_var_t dlo_mask;
        atomic_t dlo_count;
        struct dl_bw dl_bw;
        struct cpudl cpudl;

        /*
         * The "RT overload" flag: it gets set if a CPU has more than
         * one runnable RT task.
         */
        cpumask_var_t rto_mask;
        struct cpupri cpupri;

        unsigned long max_cpu_capacity;
};

extern struct root_domain def_root_domain;

#endif /* CONFIG_SMP */

/*
 * This is the main, per-CPU runqueue data structure.
 *
 * Locking rule: those places that want to lock multiple runqueues
 * (such as the load balancing or the thread migration code), lock
 * acquire operations must be ordered by ascending &runqueue.
 */
struct rq {
        /* runqueue lock: */
        raw_spinlock_t lock;

        /*
         * nr_running and cpu_load should be in the same cacheline because
         * remote CPUs use both these fields when doing load calculation.
         */
        unsigned int nr_running;
#ifdef CONFIG_NUMA_BALANCING
        unsigned int nr_numa_running;
        unsigned int nr_preferred_running;
#endif
        #define CPU_LOAD_IDX_MAX 5
        unsigned long cpu_load[CPU_LOAD_IDX_MAX];
#ifdef CONFIG_NO_HZ_COMMON
#ifdef CONFIG_SMP
        unsigned long last_load_update_tick;
#endif /* CONFIG_SMP */
        unsigned long nohz_flags;
#endif /* CONFIG_NO_HZ_COMMON */
#ifdef CONFIG_NO_HZ_FULL
        unsigned long last_sched_tick;
#endif
        /* capture load from *all* tasks on this cpu: */
        struct load_weight load;
        unsigned long nr_load_updates;
        u64 nr_switches;

        struct cfs_rq cfs;
        struct rt_rq rt;
        struct dl_rq dl;

#ifdef CONFIG_FAIR_GROUP_SCHED
        /* list of leaf cfs_rq on this cpu: */
        struct list_head leaf_cfs_rq_list;
#endif /* CONFIG_FAIR_GROUP_SCHED */

        /*
         * This is part of a global counter where only the total sum
         * over all CPUs matters. A task can increase this counter on
         * one CPU and if it got migrated afterwards it may decrease
         * it on another CPU. Always updated under the runqueue lock:
         */
        unsigned long nr_uninterruptible;

        struct task_struct *curr, *idle, *stop;
        unsigned long next_balance;
        struct mm_struct *prev_mm;

        unsigned int clock_skip_update;
        u64 clock;
        u64 clock_task;

        atomic_t nr_iowait;

#ifdef CONFIG_SMP
        struct root_domain *rd;
        struct sched_domain *sd;

        unsigned long cpu_capacity;
        unsigned long cpu_capacity_orig;

        struct callback_head *balance_callback;

        unsigned char idle_balance;
        /* For active balancing */
        int active_balance;
        int push_cpu;
        struct cpu_stop_work active_balance_work;
        /* cpu of this runqueue: */
        int cpu;
        int online;

        struct list_head cfs_tasks;

        u64 rt_avg;
        u64 age_stamp;
        u64 idle_stamp;
        u64 avg_idle;

        /* This is used to determine avg_idle's max value */
        u64 max_idle_balance_cost;
#endif

#ifdef CONFIG_IRQ_TIME_ACCOUNTING
        u64 prev_irq_time;
#endif
#ifdef CONFIG_PARAVIRT
        u64 prev_steal_time;
#endif
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
        u64 prev_steal_time_rq;
#endif

        /* calc_load related fields */
        unsigned long calc_load_update;
        long calc_load_active;

#ifdef CONFIG_SCHED_HRTICK
#ifdef CONFIG_SMP
        int hrtick_csd_pending;
        struct call_single_data hrtick_csd;
#endif
        struct hrtimer hrtick_timer;
#endif

#ifdef CONFIG_SCHEDSTATS
        /* latency stats */
        struct sched_info rq_sched_info;
        unsigned long long rq_cpu_time;
        /* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */

        /* sys_sched_yield() stats */
        unsigned int yld_count;

        /* schedule() stats */
        unsigned int sched_count;
        unsigned int sched_goidle;

        /* try_to_wake_up() stats */
        unsigned int ttwu_count;
        unsigned int ttwu_local;
#endif

#ifdef CONFIG_SMP
        struct llist_head wake_list;
#endif

#ifdef CONFIG_CPU_IDLE
        /* Must be inspected within a rcu lock section */
        struct cpuidle_state *idle_state;
#endif
};

static inline int cpu_of(struct rq *rq)
{
#ifdef CONFIG_SMP
        return rq->cpu;
#else
        return 0;
#endif
}

DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);

#define cpu_rq(cpu)             (&per_cpu(runqueues, (cpu)))
#define this_rq()               this_cpu_ptr(&runqueues)
#define task_rq(p)              cpu_rq(task_cpu(p))
#define cpu_curr(cpu)           (cpu_rq(cpu)->curr)
#define raw_rq()                raw_cpu_ptr(&runqueues)

static inline u64 __rq_clock_broken(struct rq *rq)
{
        return READ_ONCE(rq->clock);
}

static inline u64 rq_clock(struct rq *rq)
{
        lockdep_assert_held(&rq->lock);
        return rq->clock;
}

static inline u64 rq_clock_task(struct rq *rq)
{
        lockdep_assert_held(&rq->lock);
        return rq->clock_task;
}

#define RQCF_REQ_SKIP   0x01
#define RQCF_ACT_SKIP   0x02

static inline void rq_clock_skip_update(struct rq *rq, bool skip)
{
        lockdep_assert_held(&rq->lock);
        if (skip)
                rq->clock_skip_update |= RQCF_REQ_SKIP;
        else
                rq->clock_skip_update &= ~RQCF_REQ_SKIP;
}

#ifdef CONFIG_NUMA
enum numa_topology_type {
        NUMA_DIRECT,
        NUMA_GLUELESS_MESH,
        NUMA_BACKPLANE,
};
extern enum numa_topology_type sched_numa_topology_type;
extern int sched_max_numa_distance;
extern bool find_numa_distance(int distance);
#endif

#ifdef CONFIG_NUMA_BALANCING
/* The regions in numa_faults array from task_struct */
enum numa_faults_stats {
        NUMA_MEM = 0,
        NUMA_CPU,
        NUMA_MEMBUF,
        NUMA_CPUBUF
};
extern void sched_setnuma(struct task_struct *p, int node);
extern int migrate_task_to(struct task_struct *p, int cpu);
extern int migrate_swap(struct task_struct *, struct task_struct *);
#endif /* CONFIG_NUMA_BALANCING */

#ifdef CONFIG_SMP

static inline void
queue_balance_callback(struct rq *rq,
                       struct callback_head *head,
                       void (*func)(struct rq *rq))
{
        lockdep_assert_held(&rq->lock);

        if (unlikely(head->next))
                return;

        head->func = (void (*)(struct callback_head *))func;
        head->next = rq->balance_callback;
        rq->balance_callback = head;
}

extern void sched_ttwu_pending(void);

#define rcu_dereference_check_sched_domain(p) \
        rcu_dereference_check((p), \
                              lockdep_is_held(&sched_domains_mutex))

/*
 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
 * See detach_destroy_domains: synchronize_sched for details.
 *
 * The domain tree of any CPU may only be accessed from within
 * preempt-disabled sections.
 */
#define for_each_domain(cpu, __sd) \
        for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \
                        __sd; __sd = __sd->parent)

#define for_each_lower_domain(sd) for (; sd; sd = sd->child)

/**
 * highest_flag_domain - Return highest sched_domain containing flag.
 * @cpu:        The cpu whose highest level of sched domain is to
 *              be returned.
 * @flag:       The flag to check for the highest sched_domain
 *              for the given cpu.
 *
 * Returns the highest sched_domain of a cpu which contains the given flag.
 */
static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
{
        struct sched_domain *sd, *hsd = NULL;

        for_each_domain(cpu, sd) {
                if (!(sd->flags & flag))
                        break;
                hsd = sd;
        }

        return hsd;
}

static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
{
        struct sched_domain *sd;

        for_each_domain(cpu, sd) {
                if (sd->flags & flag)
                        break;
        }

        return sd;
}

DECLARE_PER_CPU(struct sched_domain *, sd_llc);
DECLARE_PER_CPU(int, sd_llc_size);
DECLARE_PER_CPU(int, sd_llc_id);
DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
DECLARE_PER_CPU(struct sched_domain *, sd_numa);
DECLARE_PER_CPU(struct sched_domain *, sd_asym);

struct sched_group_capacity {
        atomic_t ref;
        /*
         * CPU capacity of this group, SCHED_CAPACITY_SCALE being max capacity
         * for a single CPU.
         */
        unsigned int capacity;
        unsigned long next_update;
        int imbalance; /* XXX unrelated to capacity but shared group state */

        unsigned long cpumask[0]; /* iteration mask */
};

struct sched_group {
        struct sched_group *next;       /* Must be a circular list */
        atomic_t ref;

        unsigned int group_weight;
        struct sched_group_capacity *sgc;

        /*
         * The CPUs this group covers.
         *
         * NOTE: this field is variable length. (Allocated dynamically
         * by attaching extra space to the end of the structure,
         * depending on how many CPUs the kernel has booted up with)
         */
        unsigned long cpumask[0];
};

static inline struct cpumask *sched_group_cpus(struct sched_group *sg)
{
        return to_cpumask(sg->cpumask);
}

/*
 * cpumask masking which cpus in the group are allowed to iterate up the domain
 * tree.
 */
static inline struct cpumask *sched_group_mask(struct sched_group *sg)
{
        return to_cpumask(sg->sgc->cpumask);
}

/**
 * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
 * @group: The group whose first cpu is to be returned.
 */
static inline unsigned int group_first_cpu(struct sched_group *group)
{
        return cpumask_first(sched_group_cpus(group));
}

extern int group_balance_cpu(struct sched_group *sg);

#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
void register_sched_domain_sysctl(void);
void unregister_sched_domain_sysctl(void);
#else
static inline void register_sched_domain_sysctl(void)
{
}
static inline void unregister_sched_domain_sysctl(void)
{
}
#endif

#else

static inline void sched_ttwu_pending(void) { }

#endif /* CONFIG_SMP */

#include "stats.h"
#include "auto_group.h"

#ifdef CONFIG_CGROUP_SCHED

/*
 * Return the group to which this tasks belongs.
 *
 * We cannot use task_css() and friends because the cgroup subsystem
 * changes that value before the cgroup_subsys::attach() method is called,
 * therefore we cannot pin it and might observe the wrong value.
 *
 * The same is true for autogroup's p->signal->autogroup->tg, the autogroup
 * core changes this before calling sched_move_task().
 *
 * Instead we use a 'copy' which is updated from sched_move_task() while
 * holding both task_struct::pi_lock and rq::lock.
 */
static inline struct task_group *task_group(struct task_struct *p)
{
        return p->sched_task_group;
}

/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
{
#if defined(CONFIG_FAIR_GROUP_SCHED) || defined(CONFIG_RT_GROUP_SCHED)
        struct task_group *tg = task_group(p);
#endif

#ifdef CONFIG_FAIR_GROUP_SCHED
        set_task_rq_fair(&p->se, p->se.cfs_rq, tg->cfs_rq[cpu]);
        p->se.cfs_rq = tg->cfs_rq[cpu];
        p->se.parent = tg->se[cpu];
#endif

#ifdef CONFIG_RT_GROUP_SCHED
        p->rt.rt_rq  = tg->rt_rq[cpu];
        p->rt.parent = tg->rt_se[cpu];
#endif
}

#else /* CONFIG_CGROUP_SCHED */

static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
static inline struct task_group *task_group(struct task_struct *p)
{
        return NULL;
}

#endif /* CONFIG_CGROUP_SCHED */

static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
{
        set_task_rq(p, cpu);
#ifdef CONFIG_SMP
        /*
         * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
         * successfuly executed on another CPU. We must ensure that updates of
         * per-task data have been completed by this moment.
         */
        smp_wmb();
        task_thread_info(p)->cpu = cpu;
        p->wake_cpu = cpu;
#endif
}

/*
 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
 */
#ifdef CONFIG_SCHED_DEBUG
# include <linux/static_key.h>
# define const_debug __read_mostly
#else
# define const_debug const
#endif

extern const_debug unsigned int sysctl_sched_features;

#define SCHED_FEAT(name, enabled)       \
        __SCHED_FEAT_##name ,

enum {
#include "features.h"
        __SCHED_FEAT_NR,
};

#undef SCHED_FEAT

#if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
#define SCHED_FEAT(name, enabled)                                       \
static __always_inline bool static_branch_##name(struct static_key *key) \
{                                                                       \
        return static_key_##enabled(key);                               \
}

#include "features.h"

#undef SCHED_FEAT

extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
#define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
#else /* !(SCHED_DEBUG && HAVE_JUMP_LABEL) */
#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
#endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */

extern struct static_key_false sched_numa_balancing;
extern struct static_key_false sched_schedstats;

static inline u64 global_rt_period(void)
{
        return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
}

static inline u64 global_rt_runtime(void)
{
        if (sysctl_sched_rt_runtime < 0)
                return RUNTIME_INF;

        return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
}

static inline int task_current(struct rq *rq, struct task_struct *p)
{
        return rq->curr == p;
}

static inline int task_running(struct rq *rq, struct task_struct *p)
{
#ifdef CONFIG_SMP
        return p->on_cpu;
#else
        return task_current(rq, p);
#endif
}

static inline int task_on_rq_queued(struct task_struct *p)
{
        return p->on_rq == TASK_ON_RQ_QUEUED;
}

static inline int task_on_rq_migrating(struct task_struct *p)
{
        return p->on_rq == TASK_ON_RQ_MIGRATING;
}

#ifndef prepare_arch_switch
# define prepare_arch_switch(next)      do { } while (0)
#endif
#ifndef finish_arch_post_lock_switch
# define finish_arch_post_lock_switch() do { } while (0)
#endif

static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
{
#ifdef CONFIG_SMP
        /*
         * We can optimise this out completely for !SMP, because the
         * SMP rebalancing from interrupt is the only thing that cares
         * here.
         */
        next->on_cpu = 1;
#endif
}

static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
{
#ifdef CONFIG_SMP
        /*
         * After ->on_cpu is cleared, the task can be moved to a different CPU.
         * We must ensure this doesn't happen until the switch is completely
         * finished.
         *
         * In particular, the load of prev->state in finish_task_switch() must
         * happen before this.
         *
         * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
         */
        smp_store_release(&prev->on_cpu, 0);
#endif
#ifdef CONFIG_DEBUG_SPINLOCK
        /* this is a valid case when another task releases the spinlock */
        rq->lock.owner = current;
#endif
        /*
         * If we are tracking spinlock dependencies then we have to
         * fix up the runqueue lock - which gets 'carried over' from
         * prev into current:
         */
        spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);

        raw_spin_unlock_irq(&rq->lock);
}

/*
 * wake flags
 */
#define WF_SYNC         0x01            /* waker goes to sleep after wakeup */
#define WF_FORK         0x02            /* child wakeup after fork */
#define WF_MIGRATED     0x4             /* internal use, task got migrated */

/*
 * To aid in avoiding the subversion of "niceness" due to uneven distribution
 * of tasks with abnormal "nice" values across CPUs the contribution that
 * each task makes to its run queue's load is weighted according to its
 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
 * scaled version of the new time slice allocation that they receive on time
 * slice expiry etc.
 */

#define WEIGHT_IDLEPRIO                3
#define WMULT_IDLEPRIO         1431655765

extern const int sched_prio_to_weight[40];
extern const u32 sched_prio_to_wmult[40];

/*
 * {de,en}queue flags:
 *
 * DEQUEUE_SLEEP  - task is no longer runnable
 * ENQUEUE_WAKEUP - task just became runnable
 *
 * SAVE/RESTORE - an otherwise spurious dequeue/enqueue, done to ensure tasks
 *                are in a known state which allows modification. Such pairs
 *                should preserve as much state as possible.
 *
 * MOVE - paired with SAVE/RESTORE, explicitly does not preserve the location
 *        in the runqueue.
 *
 * ENQUEUE_HEAD      - place at front of runqueue (tail if not specified)
 * ENQUEUE_REPLENISH - CBS (replenish runtime and postpone deadline)
 * ENQUEUE_MIGRATED  - the task was migrated during wakeup
 *
 */

#define DEQUEUE_SLEEP           0x01
#define DEQUEUE_SAVE            0x02 /* matches ENQUEUE_RESTORE */
#define DEQUEUE_MOVE            0x04 /* matches ENQUEUE_MOVE */

#define ENQUEUE_WAKEUP          0x01
#define ENQUEUE_RESTORE         0x02
#define ENQUEUE_MOVE            0x04

#define ENQUEUE_HEAD            0x08
#define ENQUEUE_REPLENISH       0x10
#ifdef CONFIG_SMP
#define ENQUEUE_MIGRATED        0x20
#else
#define ENQUEUE_MIGRATED        0x00
#endif

#define RETRY_TASK              ((void *)-1UL)

struct sched_class {
        const struct sched_class *next;

        void (*enqueue_task) (struct rq *rq, struct task_struct *p, int flags);
        void (*dequeue_task) (struct rq *rq, struct task_struct *p, int flags);
        void (*yield_task) (struct rq *rq);
        bool (*yield_to_task) (struct rq *rq, struct task_struct *p, bool preempt);

        void (*check_preempt_curr) (struct rq *rq, struct task_struct *p, int flags);

        /*
         * It is the responsibility of the pick_next_task() method that will
         * return the next task to call put_prev_task() on the @prev task or
         * something equivalent.
         *
         * May return RETRY_TASK when it finds a higher prio class has runnable
         * tasks.
         */
        struct task_struct * (*pick_next_task) (struct rq *rq,
                                                struct task_struct *prev,
                                                struct pin_cookie cookie);
        void (*put_prev_task) (struct rq *rq, struct task_struct *p);

#ifdef CONFIG_SMP
        int  (*select_task_rq)(struct task_struct *p, int task_cpu, int sd_flag, int flags);
        void (*migrate_task_rq)(struct task_struct *p);

        void (*task_woken) (struct rq *this_rq, struct task_struct *task);

        void (*set_cpus_allowed)(struct task_struct *p,
                                 const struct cpumask *newmask);

        void (*rq_online)(struct rq *rq);
        void (*rq_offline)(struct rq *rq);
#endif

        void (*set_curr_task) (struct rq *rq);
        void (*task_tick) (struct rq *rq, struct task_struct *p, int queued);
        void (*task_fork) (struct task_struct *p);
        void (*task_dead) (struct task_struct *p);

        /*
         * The switched_from() call is allowed to drop rq->lock, therefore we
         * cannot assume the switched_from/switched_to pair is serliazed by
         * rq->lock. They are however serialized by p->pi_lock.
         */
        void (*switched_from) (struct rq *this_rq, struct task_struct *task);
        void (*switched_to) (struct rq *this_rq, struct task_struct *task);
        void (*prio_changed) (struct rq *this_rq, struct task_struct *task,
                             int oldprio);

        unsigned int (*get_rr_interval) (struct rq *rq,
                                         struct task_struct *task);

        void (*update_curr) (struct rq *rq);

#define TASK_SET_GROUP  0
#define TASK_MOVE_GROUP 1

#ifdef CONFIG_FAIR_GROUP_SCHED
        void (*task_change_group) (struct task_struct *p, int type);
#endif
};

static inline void put_prev_task(struct rq *rq, struct task_struct *prev)
{
        prev->sched_class->put_prev_task(rq, prev);
}

#define sched_class_highest (&stop_sched_class)
#define for_each_class(class) \
   for (class = sched_class_highest; class; class = class->next)

extern const struct sched_class stop_sched_class;
extern const struct sched_class dl_sched_class;
extern const struct sched_class rt_sched_class;
extern const struct sched_class fair_sched_class;
extern const struct sched_class idle_sched_class;


#ifdef CONFIG_SMP

extern void update_group_capacity(struct sched_domain *sd, int cpu);

extern void trigger_load_balance(struct rq *rq);

extern void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask);

#endif

#ifdef CONFIG_CPU_IDLE
static inline void idle_set_state(struct rq *rq,
                                  struct cpuidle_state *idle_state)
{
        rq->idle_state = idle_state;
}

static inline struct cpuidle_state *idle_get_state(struct rq *rq)
{
        WARN_ON(!rcu_read_lock_held());
        return rq->idle_state;
}
#else
static inline void idle_set_state(struct rq *rq,
                                  struct cpuidle_state *idle_state)
{
}

static inline struct cpuidle_state *idle_get_state(struct rq *rq)
{
        return NULL;
}
#endif

extern void sysrq_sched_debug_show(void);
extern void sched_init_granularity(void);
extern void update_max_interval(void);

extern void init_sched_dl_class(void);
extern void init_sched_rt_class(void);
extern void init_sched_fair_class(void);

extern void resched_curr(struct rq *rq);
extern void resched_cpu(int cpu);

extern struct rt_bandwidth def_rt_bandwidth;
extern void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime);

extern struct dl_bandwidth def_dl_bandwidth;
extern void init_dl_bandwidth(struct dl_bandwidth *dl_b, u64 period, u64 runtime);
extern void init_dl_task_timer(struct sched_dl_entity *dl_se);

unsigned long to_ratio(u64 period, u64 runtime);

extern void init_entity_runnable_average(struct sched_entity *se);
extern void post_init_entity_util_avg(struct sched_entity *se);

#ifdef CONFIG_NO_HZ_FULL
extern bool sched_can_stop_tick(struct rq *rq);

/*
 * Tick may be needed by tasks in the runqueue depending on their policy and
 * requirements. If tick is needed, lets send the target an IPI to kick it out of
 * nohz mode if necessary.
 */
static inline void sched_update_tick_dependency(struct rq *rq)
{
        int cpu;

        if (!tick_nohz_full_enabled())
                return;

        cpu = cpu_of(rq);

        if (!tick_nohz_full_cpu(cpu))
                return;

        if (sched_can_stop_tick(rq))
                tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED);
        else
                tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
}
#else
static inline void sched_update_tick_dependency(struct rq *rq) { }
#endif

static inline void add_nr_running(struct rq *rq, unsigned count)
{
        unsigned prev_nr = rq->nr_running;

        rq->nr_running = prev_nr + count;

        if (prev_nr < 2 && rq->nr_running >= 2) {
#ifdef CONFIG_SMP
                if (!rq->rd->overload)
                        rq->rd->overload = true;
#endif
        }

        sched_update_tick_dependency(rq);
}

static inline void sub_nr_running(struct rq *rq, unsigned count)
{
        rq->nr_running -= count;
        /* Check if we still need preemption */
        sched_update_tick_dependency(rq);
}

static inline void rq_last_tick_reset(struct rq *rq)
{
#ifdef CONFIG_NO_HZ_FULL
        rq->last_sched_tick = jiffies;
#endif
}

extern void update_rq_clock(struct rq *rq);

extern void activate_task(struct rq *rq, struct task_struct *p, int flags);
extern void deactivate_task(struct rq *rq, struct task_struct *p, int flags);

extern void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags);

extern const_debug unsigned int sysctl_sched_time_avg;
extern const_debug unsigned int sysctl_sched_nr_migrate;
extern const_debug unsigned int sysctl_sched_migration_cost;

static inline u64 sched_avg_period(void)
{
        return (u64)sysctl_sched_time_avg * NSEC_PER_MSEC / 2;
}

#ifdef CONFIG_SCHED_HRTICK

/*
 * Use hrtick when:
 *  - enabled by features
 *  - hrtimer is actually high res
 */
static inline int hrtick_enabled(struct rq *rq)
{
        if (!sched_feat(HRTICK))
                return 0;
        if (!cpu_active(cpu_of(rq)))
                return 0;
        return hrtimer_is_hres_active(&rq->hrtick_timer);
}

void hrtick_start(struct rq *rq, u64 delay);

#else

static inline int hrtick_enabled(struct rq *rq)
{
        return 0;
}

#endif /* CONFIG_SCHED_HRTICK */

#ifdef CONFIG_SMP
extern void sched_avg_update(struct rq *rq);

#ifndef arch_scale_freq_capacity
static __always_inline
unsigned long arch_scale_freq_capacity(struct sched_domain *sd, int cpu)
{
        return SCHED_CAPACITY_SCALE;
}
#endif

#ifndef arch_scale_cpu_capacity
static __always_inline
unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
{
        if (sd && (sd->flags & SD_SHARE_CPUCAPACITY) && (sd->span_weight > 1))
                return sd->smt_gain / sd->span_weight;

        return SCHED_CAPACITY_SCALE;
}
#endif

static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
{
        rq->rt_avg += rt_delta * arch_scale_freq_capacity(NULL, cpu_of(rq));
        sched_avg_update(rq);
}
#else
static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta) { }
static inline void sched_avg_update(struct rq *rq) { }
#endif

struct rq_flags {
        unsigned long flags;
        struct pin_cookie cookie;
};

struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
        __acquires(rq->lock);
struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
        __acquires(p->pi_lock)
        __acquires(rq->lock);

static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
        __releases(rq->lock)
{
        lockdep_unpin_lock(&rq->lock, rf->cookie);
        raw_spin_unlock(&rq->lock);
}

static inline void
task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
        __releases(rq->lock)
        __releases(p->pi_lock)
{
        lockdep_unpin_lock(&rq->lock, rf->cookie);
        raw_spin_unlock(&rq->lock);
        raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
}

#ifdef CONFIG_SMP
#ifdef CONFIG_PREEMPT

static inline void double_rq_lock(struct rq *rq1, struct rq *rq2);

/*
 * fair double_lock_balance: Safely acquires both rq->locks in a fair
 * way at the expense of forcing extra atomic operations in all
 * invocations.  This assures that the double_lock is acquired using the
 * same underlying policy as the spinlock_t on this architecture, which
 * reduces latency compared to the unfair variant below.  However, it
 * also adds more overhead and therefore may reduce throughput.
 */
static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
        __releases(this_rq->lock)
        __acquires(busiest->lock)
        __acquires(this_rq->lock)
{
        raw_spin_unlock(&this_rq->lock);
        double_rq_lock(this_rq, busiest);

        return 1;
}

#else
/*
 * Unfair double_lock_balance: Optimizes throughput at the expense of
 * latency by eliminating extra atomic operations when the locks are
 * already in proper order on entry.  This favors lower cpu-ids and will
 * grant the double lock to lower cpus over higher ids under contention,
 * regardless of entry order into the function.
 */
static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
        __releases(this_rq->lock)
        __acquires(busiest->lock)
        __acquires(this_rq->lock)
{
        int ret = 0;

        if (unlikely(!raw_spin_trylock(&busiest->lock))) {
                if (busiest < this_rq) {
                        raw_spin_unlock(&this_rq->lock);
                        raw_spin_lock(&busiest->lock);
                        raw_spin_lock_nested(&this_rq->lock,
                                              SINGLE_DEPTH_NESTING);
                        ret = 1;
                } else
                        raw_spin_lock_nested(&busiest->lock,
                                              SINGLE_DEPTH_NESTING);
        }
        return ret;
}

#endif /* CONFIG_PREEMPT */

/*
 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
 */
static inline int double_lock_balance(struct rq *this_rq, struct rq *busiest)
{
        if (unlikely(!irqs_disabled())) {
                /* printk() doesn't work good under rq->lock */
                raw_spin_unlock(&this_rq->lock);
                BUG_ON(1);
        }

        return _double_lock_balance(this_rq, busiest);
}

static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
        __releases(busiest->lock)
{
        raw_spin_unlock(&busiest->lock);
        lock_set_subclass(&this_rq->lock.dep_map, 0, _RET_IP_);
}

static inline void double_lock(spinlock_t *l1, spinlock_t *l2)
{
        if (l1 > l2)
                swap(l1, l2);

        spin_lock(l1);
        spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
}

static inline void double_lock_irq(spinlock_t *l1, spinlock_t *l2)
{
        if (l1 > l2)
                swap(l1, l2);

        spin_lock_irq(l1);
        spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
}

static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2)
{
        if (l1 > l2)
                swap(l1, l2);

        raw_spin_lock(l1);
        raw_spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
}

/*
 * double_rq_lock - safely lock two runqueues
 *
 * Note this does not disable interrupts like task_rq_lock,
 * you need to do so manually before calling.
 */
static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
        __acquires(rq1->lock)
        __acquires(rq2->lock)
{
        BUG_ON(!irqs_disabled());
        if (rq1 == rq2) {
                raw_spin_lock(&rq1->lock);
                __acquire(rq2->lock);   /* Fake it out ;) */
        } else {
                if (rq1 < rq2) {
                        raw_spin_lock(&rq1->lock);
                        raw_spin_lock_nested(&rq2->lock, SINGLE_DEPTH_NESTING);
                } else {
                        raw_spin_lock(&rq2->lock);
                        raw_spin_lock_nested(&rq1->lock, SINGLE_DEPTH_NESTING);
                }
        }
}

/*
 * double_rq_unlock - safely unlock two runqueues
 *
 * Note this does not restore interrupts like task_rq_unlock,
 * you need to do so manually after calling.
 */
static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
        __releases(rq1->lock)
        __releases(rq2->lock)
{
        raw_spin_unlock(&rq1->lock);
        if (rq1 != rq2)
                raw_spin_unlock(&rq2->lock);
        else
                __release(rq2->lock);
}

#else /* CONFIG_SMP */

/*
 * double_rq_lock - safely lock two runqueues
 *
 * Note this does not disable interrupts like task_rq_lock,
 * you need to do so manually before calling.
 */
static inline void double_rq_lock(struct rq *rq1, struct rq *rq2)
        __acquires(rq1->lock)
        __acquires(rq2->lock)
{
        BUG_ON(!irqs_disabled());
        BUG_ON(rq1 != rq2);
        raw_spin_lock(&rq1->lock);
        __acquire(rq2->lock);   /* Fake it out ;) */
}

/*
 * double_rq_unlock - safely unlock two runqueues
 *
 * Note this does not restore interrupts like task_rq_unlock,
 * you need to do so manually after calling.
 */
static inline void double_rq_unlock(struct rq *rq1, struct rq *rq2)
        __releases(rq1->lock)
        __releases(rq2->lock)
{
        BUG_ON(rq1 != rq2);
        raw_spin_unlock(&rq1->lock);
        __release(rq2->lock);
}

#endif

extern struct sched_entity *__pick_first_entity(struct cfs_rq *cfs_rq);
extern struct sched_entity *__pick_last_entity(struct cfs_rq *cfs_rq);

#ifdef  CONFIG_SCHED_DEBUG
extern void print_cfs_stats(struct seq_file *m, int cpu);
extern void print_rt_stats(struct seq_file *m, int cpu);
extern void print_dl_stats(struct seq_file *m, int cpu);
extern void
print_cfs_rq(struct seq_file *m, int cpu, struct cfs_rq *cfs_rq);

#ifdef CONFIG_NUMA_BALANCING
extern void
show_numa_stats(struct task_struct *p, struct seq_file *m);
extern void
print_numa_stats(struct seq_file *m, int node, unsigned long tsf,
        unsigned long tpf, unsigned long gsf, unsigned long gpf);
#endif /* CONFIG_NUMA_BALANCING */
#endif /* CONFIG_SCHED_DEBUG */

extern void init_cfs_rq(struct cfs_rq *cfs_rq);
extern void init_rt_rq(struct rt_rq *rt_rq);
extern void init_dl_rq(struct dl_rq *dl_rq);

extern void cfs_bandwidth_usage_inc(void);
extern void cfs_bandwidth_usage_dec(void);

#ifdef CONFIG_NO_HZ_COMMON
enum rq_nohz_flag_bits {
        NOHZ_TICK_STOPPED,
        NOHZ_BALANCE_KICK,
};

#define nohz_flags(cpu) (&cpu_rq(cpu)->nohz_flags)

extern void nohz_balance_exit_idle(unsigned int cpu);
#else
static inline void nohz_balance_exit_idle(unsigned int cpu) { }
#endif

#ifdef CONFIG_IRQ_TIME_ACCOUNTING

DECLARE_PER_CPU(u64, cpu_hardirq_time);
DECLARE_PER_CPU(u64, cpu_softirq_time);

#ifndef CONFIG_64BIT
DECLARE_PER_CPU(seqcount_t, irq_time_seq);

static inline void irq_time_write_begin(void)
{
        __this_cpu_inc(irq_time_seq.sequence);
        smp_wmb();
}

static inline void irq_time_write_end(void)
{
        smp_wmb();
        __this_cpu_inc(irq_time_seq.sequence);
}

static inline u64 irq_time_read(int cpu)
{
        u64 irq_time;
        unsigned seq;

        do {
                seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
                irq_time = per_cpu(cpu_softirq_time, cpu) +
                           per_cpu(cpu_hardirq_time, cpu);
        } while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));

        return irq_time;
}
#else /* CONFIG_64BIT */
static inline void irq_time_write_begin(void)
{
}

static inline void irq_time_write_end(void)
{
}

static inline u64 irq_time_read(int cpu)
{
        return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
}
#endif /* CONFIG_64BIT */
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */

#ifdef CONFIG_CPU_FREQ
DECLARE_PER_CPU(struct update_util_data *, cpufreq_update_util_data);

/**
 * cpufreq_update_util - Take a note about CPU utilization changes.
 * @time: Current time.
 * @util: Current utilization.
 * @max: Utilization ceiling.
 *
 * This function is called by the scheduler on every invocation of
 * update_load_avg() on the CPU whose utilization is being updated.
 *
 * It can only be called from RCU-sched read-side critical sections.
 */
static inline void cpufreq_update_util(u64 time, unsigned long util, unsigned long max)
{
       struct update_util_data *data;

       data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data));
       if (data)
               data->func(data, time, util, max);
}

/**
 * cpufreq_trigger_update - Trigger CPU performance state evaluation if needed.
 * @time: Current time.
 *
 * The way cpufreq is currently arranged requires it to evaluate the CPU
 * performance state (frequency/voltage) on a regular basis to prevent it from
 * being stuck in a completely inadequate performance level for too long.
 * That is not guaranteed to happen if the updates are only triggered from CFS,
 * though, because they may not be coming in if RT or deadline tasks are active
 * all the time (or there are RT and DL tasks only).
 *
 * As a workaround for that issue, this function is called by the RT and DL
 * sched classes to trigger extra cpufreq updates to prevent it from stalling,
 * but that really is a band-aid.  Going forward it should be replaced with
 * solutions targeted more specifically at RT and DL tasks.
 */
static inline void cpufreq_trigger_update(u64 time)
{
        cpufreq_update_util(time, ULONG_MAX, 0);
}
#else
static inline void cpufreq_update_util(u64 time, unsigned long util, unsigned long max) {}
static inline void cpufreq_trigger_update(u64 time) {}
#endif /* CONFIG_CPU_FREQ */

#ifdef arch_scale_freq_capacity
#ifndef arch_scale_freq_invariant
#define arch_scale_freq_invariant()     (true)
#endif
#else /* arch_scale_freq_capacity */
#define arch_scale_freq_invariant()     (false)
#endif