sched: Move all scheduler bits into kernel/sched/

There's too many sched*.[ch] files in kernel/, give them their own
directory.

(No code changed, other than Makefile glue added.)

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 1064 insertions, 0 deletions

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
new file mode 100644
index 000000000000..c2e780234c31
--- /dev/null
+++ b/kernel/sched/sched.h
@@ -0,0 +1,1064 @@
+
+#include <linux/sched.h>
+#include <linux/mutex.h>
+#include <linux/spinlock.h>
+#include <linux/stop_machine.h>
+
+#include "cpupri.h"
+
+extern __read_mostly int scheduler_running;
+
+/*
+ * Convert user-nice values [ -20 ... 0 ... 19 ]
+ * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
+ * and back.
+ */
+#define NICE_TO_PRIO(nice)      (MAX_RT_PRIO + (nice) + 20)
+#define PRIO_TO_NICE(prio)      ((prio) - MAX_RT_PRIO - 20)
+#define TASK_NICE(p)            PRIO_TO_NICE((p)->static_prio)
+
+/*
+ * 'User priority' is the nice value converted to something we
+ * can work with better when scaling various scheduler parameters,
+ * it's a [ 0 ... 39 ] range.
+ */
+#define USER_PRIO(p)            ((p)-MAX_RT_PRIO)
+#define TASK_USER_PRIO(p)       USER_PRIO((p)->static_prio)
+#define MAX_USER_PRIO           (USER_PRIO(MAX_PRIO))
+
+/*
+ * Helpers for converting nanosecond timing to jiffy resolution
+ */
+#define NS_TO_JIFFIES(TIME)     ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
+
+#define NICE_0_LOAD             SCHED_LOAD_SCALE
+#define NICE_0_SHIFT            SCHED_LOAD_SHIFT
+
+/*
+ * These are the 'tuning knobs' of the scheduler:
+ *
+ * default timeslice is 100 msecs (used only for SCHED_RR tasks).
+ * Timeslices get refilled after they expire.
+ */
+#define DEF_TIMESLICE           (100 * HZ / 1000)
+
+/*
+ * single value that denotes runtime == period, ie unlimited time.
+ */
+#define RUNTIME_INF     ((u64)~0ULL)
+
+static inline int rt_policy(int policy)
+{
+        if (policy == SCHED_FIFO || policy == SCHED_RR)
+                return 1;
+        return 0;
+}
+
+static inline int task_has_rt_policy(struct task_struct *p)
+{
+        return rt_policy(p->policy);
+}
+
+/*
+ * 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;
+};
+
+extern struct mutex sched_domains_mutex;
+
+#ifdef CONFIG_CGROUP_SCHED
+
+#include <linux/cgroup.h>
+
+struct cfs_rq;
+struct rt_rq;
+
+static LIST_HEAD(task_groups);
+
+struct cfs_bandwidth {
+#ifdef CONFIG_CFS_BANDWIDTH
+        raw_spinlock_t lock;
+        ktime_t period;
+        u64 quota, runtime;
+        s64 hierarchal_quota;
+        u64 runtime_expires;
+
+        int idle, timer_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;
+
+        atomic_t load_weight;
+#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
+
+/* Default task group.
+ *      Every task in system belong to this group at bootup.
+ */
+extern struct task_group root_task_group;
+
+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 unregister_fair_sched_group(struct task_group *tg, int cpu);
+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 int sched_group_set_shares(struct task_group *tg, unsigned long shares);
+
+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);
+
+#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 long 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;
+
+        struct list_head tasks;
+        struct list_head *balance_iterator;
+
+        /*
+         * '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_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_SMP
+        /*
+         * the part of load.weight contributed by tasks
+         */
+        unsigned long task_weight;
+
+        /*
+         *   h_load = weight * f(tg)
+         *
+         * Where f(tg) is the recursive weight fraction assigned to
+         * this group.
+         */
+        unsigned long h_load;
+
+        /*
+         * Maintaining per-cpu shares distribution for group scheduling
+         *
+         * load_stamp is the last time we updated the load average
+         * load_last is the last time we updated the load average and saw load
+         * load_unacc_exec_time is currently unaccounted execution time
+         */
+        u64 load_avg;
+        u64 load_period;
+        u64 load_stamp, load_last, load_unacc_exec_time;
+
+        unsigned long load_contribution;
+#endif /* CONFIG_SMP */
+#ifdef CONFIG_CFS_BANDWIDTH
+        int runtime_enabled;
+        u64 runtime_expires;
+        s64 runtime_remaining;
+
+        u64 throttled_timestamp;
+        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;
+}
+
+/* Real-Time classes' related field in a runqueue: */
+struct rt_rq {
+        struct rt_prio_array active;
+        unsigned long rt_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;
+#endif
+        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 list_head leaf_rt_rq_list;
+        struct task_group *tg;
+#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;
+
+        /*
+         * 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;
+};
+
+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 long nr_running;
+        #define CPU_LOAD_IDX_MAX 5
+        unsigned long cpu_load[CPU_LOAD_IDX_MAX];
+        unsigned long last_load_update_tick;
+#ifdef CONFIG_NO_HZ
+        u64 nohz_stamp;
+        unsigned char nohz_balance_kick;
+#endif
+        int skip_clock_update;
+
+        /* 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;
+
+#ifdef CONFIG_FAIR_GROUP_SCHED
+        /* list of leaf cfs_rq on this cpu: */
+        struct list_head leaf_cfs_rq_list;
+#endif
+#ifdef CONFIG_RT_GROUP_SCHED
+        struct list_head leaf_rt_rq_list;
+#endif
+
+        /*
+         * 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;
+
+        u64 clock;
+        u64 clock_task;
+
+        atomic_t nr_iowait;
+
+#ifdef CONFIG_SMP
+        struct root_domain *rd;
+        struct sched_domain *sd;
+
+        unsigned long cpu_power;
+
+        unsigned char idle_balance;
+        /* For active balancing */
+        int post_schedule;
+        int active_balance;
+        int push_cpu;
+        struct cpu_stop_work active_balance_work;
+        /* cpu of this runqueue: */
+        int cpu;
+        int online;
+
+        u64 rt_avg;
+        u64 age_stamp;
+        u64 idle_stamp;
+        u64 avg_idle;
+#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_switch;
+        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
+};
+
+static inline int cpu_of(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+        return rq->cpu;
+#else
+        return 0;
+#endif
+}
+
+DECLARE_PER_CPU(struct rq, runqueues);
+
+#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 cpu_rq(cpu)             (&per_cpu(runqueues, (cpu)))
+#define this_rq()               (&__get_cpu_var(runqueues))
+#define task_rq(p)              cpu_rq(task_cpu(p))
+#define cpu_curr(cpu)           (cpu_rq(cpu)->curr)
+#define raw_rq()                (&__raw_get_cpu_var(runqueues))
+
+#include "stats.h"
+#include "auto_group.h"
+
+#ifdef CONFIG_CGROUP_SCHED
+
+/*
+ * Return the group to which this tasks belongs.
+ *
+ * We use task_subsys_state_check() and extend the RCU verification with
+ * pi->lock and rq->lock because cpu_cgroup_attach() holds those locks for each
+ * task it moves into the cgroup. Therefore by holding either of those locks,
+ * we pin the task to the current cgroup.
+ */
+static inline struct task_group *task_group(struct task_struct *p)
+{
+        struct task_group *tg;
+        struct cgroup_subsys_state *css;
+
+        css = task_subsys_state_check(p, cpu_cgroup_subsys_id,
+                        lockdep_is_held(&p->pi_lock) ||
+                        lockdep_is_held(&task_rq(p)->lock));
+        tg = container_of(css, struct task_group, css);
+
+        return autogroup_task_group(p, tg);
+}
+
+/* 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
+        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;
+#endif
+}
+
+/*
+ * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
+ */
+#ifdef CONFIG_SCHED_DEBUG
+# 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"
+};
+
+#undef SCHED_FEAT
+
+#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
+
+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
+}
+
+
+#ifndef prepare_arch_switch
+# define prepare_arch_switch(next)      do { } while (0)
+#endif
+#ifndef finish_arch_switch
+# define finish_arch_switch(prev)       do { } while (0)
+#endif
+
+#ifndef __ARCH_WANT_UNLOCKED_CTXSW
+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.
+         */
+        smp_wmb();
+        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);
+}
+
+#else /* __ARCH_WANT_UNLOCKED_CTXSW */
+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
+#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
+        raw_spin_unlock_irq(&rq->lock);
+#else
+        raw_spin_unlock(&rq->lock);
+#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.
+         */
+        smp_wmb();
+        prev->on_cpu = 0;
+#endif
+#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
+        local_irq_enable();
+#endif
+}
+#endif /* __ARCH_WANT_UNLOCKED_CTXSW */
+
+
+static inline void update_load_add(struct load_weight *lw, unsigned long inc)
+{
+        lw->weight += inc;
+        lw->inv_weight = 0;
+}
+
+static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
+{
+        lw->weight -= dec;
+        lw->inv_weight = 0;
+}
+
+static inline void update_load_set(struct load_weight *lw, unsigned long w)
+{
+        lw->weight = w;
+        lw->inv_weight = 0;
+}
+
+/*
+ * 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
+
+/*
+ * Nice levels are multiplicative, with a gentle 10% change for every
+ * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
+ * nice 1, it will get ~10% less CPU time than another CPU-bound task
+ * that remained on nice 0.
+ *
+ * The "10% effect" is relative and cumulative: from _any_ nice level,
+ * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
+ * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
+ * If a task goes up by ~10% and another task goes down by ~10% then
+ * the relative distance between them is ~25%.)
+ */
+static const int prio_to_weight[40] = {
+ /* -20 */     88761,     71755,     56483,     46273,     36291,
+ /* -15 */     29154,     23254,     18705,     14949,     11916,
+ /* -10 */      9548,      7620,      6100,      4904,      3906,
+ /*  -5 */      3121,      2501,      1991,      1586,      1277,
+ /*   0 */      1024,       820,       655,       526,       423,
+ /*   5 */       335,       272,       215,       172,       137,
+ /*  10 */       110,        87,        70,        56,        45,
+ /*  15 */        36,        29,        23,        18,        15,
+};
+
+/*
+ * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
+ *
+ * In cases where the weight does not change often, we can use the
+ * precalculated inverse to speed up arithmetics by turning divisions
+ * into multiplications:
+ */
+static const u32 prio_to_wmult[40] = {
+ /* -20 */     48388,     59856,     76040,     92818,    118348,
+ /* -15 */    147320,    184698,    229616,    287308,    360437,
+ /* -10 */    449829,    563644,    704093,    875809,   1099582,
+ /*  -5 */   1376151,   1717300,   2157191,   2708050,   3363326,
+ /*   0 */   4194304,   5237765,   6557202,   8165337,  10153587,
+ /*   5 */  12820798,  15790321,  19976592,  24970740,  31350126,
+ /*  10 */  39045157,  49367440,  61356676,  76695844,  95443717,
+ /*  15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
+};
+
+/* Time spent by the tasks of the cpu accounting group executing in ... */
+enum cpuacct_stat_index {
+        CPUACCT_STAT_USER,      /* ... user mode */
+        CPUACCT_STAT_SYSTEM,    /* ... kernel mode */
+
+        CPUACCT_STAT_NSTATS,
+};
+
+
+#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 rt_sched_class;
+extern const struct sched_class fair_sched_class;
+extern const struct sched_class idle_sched_class;
+
+
+#ifdef CONFIG_SMP
+
+extern void trigger_load_balance(struct rq *rq, int cpu);
+extern void idle_balance(int this_cpu, struct rq *this_rq);
+
+#else   /* CONFIG_SMP */
+
+static inline void idle_balance(int cpu, struct rq *rq)
+{
+}
+
+#endif
+
+extern void sysrq_sched_debug_show(void);
+extern void sched_init_granularity(void);
+extern void update_max_interval(void);
+extern void update_group_power(struct sched_domain *sd, int cpu);
+extern int update_runtime(struct notifier_block *nfb, unsigned long action, void *hcpu);
+extern void init_sched_rt_class(void);
+extern void init_sched_fair_class(void);
+
+extern void resched_task(struct task_struct *p);
+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 void update_cpu_load(struct rq *this_rq);
+
+#ifdef CONFIG_CGROUP_CPUACCT
+extern void cpuacct_charge(struct task_struct *tsk, u64 cputime);
+extern void cpuacct_update_stats(struct task_struct *tsk,
+                enum cpuacct_stat_index idx, cputime_t val);
+#else
+static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
+static inline void cpuacct_update_stats(struct task_struct *tsk,
+                enum cpuacct_stat_index idx, cputime_t val) {}
+#endif
+
+static inline void inc_nr_running(struct rq *rq)
+{
+        rq->nr_running++;
+}
+
+static inline void dec_nr_running(struct rq *rq)
+{
+        rq->nr_running--;
+}
+
+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;
+}
+
+void calc_load_account_idle(struct rq *this_rq);
+
+#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);
+
+#endif /* CONFIG_SCHED_HRTICK */
+
+#ifdef CONFIG_SMP
+extern void sched_avg_update(struct rq *rq);
+static inline void sched_rt_avg_update(struct rq *rq, u64 rt_delta)
+{
+        rq->rt_avg += rt_delta;
+        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
+
+extern void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period);
+
+#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_);
+}
+
+/*
+ * 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);
+extern void print_cfs_stats(struct seq_file *m, int cpu);
+extern void print_rt_stats(struct seq_file *m, int cpu);
+
+extern void init_cfs_rq(struct cfs_rq *cfs_rq);
+extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq);
+extern void unthrottle_offline_cfs_rqs(struct rq *rq);
+
+extern void account_cfs_bandwidth_used(int enabled, int was_enabled);