X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=kernel%2Fsched.c;h=74624e037d06c24049a7565c397fbe17249c58a8;hb=97bf2856c6014879bd04983a3e9dfcdac1e7fe85;hp=1493acff560f9cc49d0a900fae8536cf2600b6e7;hpb=5273a3df6485dc2ad6aa7ddd441b9a21970f003b;p=linux-2.6.git diff --git a/kernel/sched.c b/kernel/sched.c index 1493acff5..74624e037 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -15,6 +15,7 @@ * and per-CPU runqueues. Cleanups and useful suggestions * by Davide Libenzi, preemptible kernel bits by Robert Love. * 2003-09-03 Interactivity tuning by Con Kolivas. + * 2004-04-02 Scheduler domains code by Nick Piggin */ #include @@ -26,25 +27,36 @@ #include #include #include +#include #include #include +#include #include #include -#include +#include +#include +#include #include #include #include +#include #include #include #include +#include #include #include - -#ifdef CONFIG_NUMA -#define cpu_to_node_mask(cpu) node_to_cpumask(cpu_to_node(cpu)) -#else -#define cpu_to_node_mask(cpu) (cpu_online_map) -#endif +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include /* * Convert user-nice values [ -20 ... 0 ... 19 ] @@ -63,8 +75,6 @@ #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)) -#define AVG_TIMESLICE (MIN_TIMESLICE + ((MAX_TIMESLICE - MIN_TIMESLICE) *\ - (MAX_PRIO-1-NICE_TO_PRIO(0))/(MAX_USER_PRIO - 1))) /* * Some helpers for converting nanosecond timing to jiffy resolution @@ -75,12 +85,12 @@ /* * These are the 'tuning knobs' of the scheduler: * - * Minimum timeslice is 10 msecs, default timeslice is 100 msecs, - * maximum timeslice is 200 msecs. Timeslices get refilled after - * they expire. + * Minimum timeslice is 5 msecs (or 1 jiffy, whichever is larger), + * default timeslice is 100 msecs, maximum timeslice is 800 msecs. + * Timeslices get refilled after they expire. */ -#define MIN_TIMESLICE ( 10 * HZ / 1000) -#define MAX_TIMESLICE (200 * HZ / 1000) +#define MIN_TIMESLICE max(5 * HZ / 1000, 1) +#define DEF_TIMESLICE (100 * HZ / 1000) #define ON_RUNQUEUE_WEIGHT 30 #define CHILD_PENALTY 95 #define PARENT_PENALTY 100 @@ -88,11 +98,9 @@ #define PRIO_BONUS_RATIO 25 #define MAX_BONUS (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100) #define INTERACTIVE_DELTA 2 -#define MAX_SLEEP_AVG (AVG_TIMESLICE * MAX_BONUS) +#define MAX_SLEEP_AVG (DEF_TIMESLICE * MAX_BONUS) #define STARVATION_LIMIT (MAX_SLEEP_AVG) #define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG)) -#define NODE_THRESHOLD 125 -#define CREDIT_LIMIT 100 /* * If a task is 'interactive' then we reinsert it in the active @@ -126,12 +134,14 @@ (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \ MAX_SLEEP_AVG) +#define GRANULARITY (10 * HZ / 1000 ? : 1) + #ifdef CONFIG_SMP -#define TIMESLICE_GRANULARITY(p) (MIN_TIMESLICE * \ +#define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \ num_online_cpus()) #else -#define TIMESLICE_GRANULARITY(p) (MIN_TIMESLICE * \ +#define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1))) #endif @@ -139,7 +149,7 @@ (v1) * (v2_max) / (v1_max) #define DELTA(p) \ - (SCALE(TASK_NICE(p), 40, MAX_USER_PRIO*PRIO_BONUS_RATIO/100) + \ + (SCALE(TASK_NICE(p) + 20, 40, MAX_BONUS) - 20 * MAX_BONUS / 40 + \ INTERACTIVE_DELTA) #define TASK_INTERACTIVE(p) \ @@ -149,46 +159,41 @@ (JIFFIES_TO_NS(MAX_SLEEP_AVG * \ (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1)) -#define HIGH_CREDIT(p) \ - ((p)->interactive_credit > CREDIT_LIMIT) - -#define LOW_CREDIT(p) \ - ((p)->interactive_credit < -CREDIT_LIMIT) - #define TASK_PREEMPTS_CURR(p, rq) \ ((p)->prio < (rq)->curr->prio) +#define SCALE_PRIO(x, prio) \ + max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE) + +static unsigned int static_prio_timeslice(int static_prio) +{ + if (static_prio < NICE_TO_PRIO(0)) + return SCALE_PRIO(DEF_TIMESLICE * 4, static_prio); + else + return SCALE_PRIO(DEF_TIMESLICE, static_prio); +} + /* - * BASE_TIMESLICE scales user-nice values [ -20 ... 19 ] - * to time slice values. + * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ] + * to time slice values: [800ms ... 100ms ... 5ms] * * The higher a thread's priority, the bigger timeslices * it gets during one round of execution. But even the lowest * priority thread gets MIN_TIMESLICE worth of execution time. - * - * task_timeslice() is the interface that is used by the scheduler. */ -#define BASE_TIMESLICE(p) (MIN_TIMESLICE + \ - ((MAX_TIMESLICE - MIN_TIMESLICE) * \ - (MAX_PRIO-1 - (p)->static_prio) / (MAX_USER_PRIO-1))) - -static inline unsigned int task_timeslice(task_t *p) +static inline unsigned int task_timeslice(struct task_struct *p) { - return BASE_TIMESLICE(p); + return static_prio_timeslice(p->static_prio); } /* * These are the runqueue data structures: */ -#define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long)) - -typedef struct runqueue runqueue_t; - struct prio_array { - int nr_active; - unsigned long bitmap[BITMAP_SIZE]; + unsigned int nr_active; + DECLARE_BITMAP(bitmap, MAX_PRIO+1); /* include 1 bit for delimiter */ struct list_head queue[MAX_PRIO]; }; @@ -199,101 +204,213 @@ struct prio_array { * (such as the load balancing or the thread migration code), lock * acquire operations must be ordered by ascending &runqueue. */ -struct runqueue { +struct rq { 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; + unsigned long raw_weighted_load; +#ifdef CONFIG_SMP + unsigned long cpu_load[3]; +#endif unsigned long long nr_switches; - unsigned long nr_running, expired_timestamp, nr_uninterruptible, - timestamp_last_tick; - task_t *curr, *idle; + + /* + * 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; + + unsigned long expired_timestamp; + /* Cached timestamp set by update_cpu_clock() */ + unsigned long long most_recent_timestamp; + struct task_struct *curr, *idle; + unsigned long next_balance; struct mm_struct *prev_mm; - prio_array_t *active, *expired, arrays[2]; - int best_expired_prio, prev_cpu_load[NR_CPUS]; -#ifdef CONFIG_NUMA - atomic_t *node_nr_running; - int prev_node_load[MAX_NUMNODES]; -#endif - task_t *migration_thread; + struct prio_array *active, *expired, arrays[2]; + int best_expired_prio; + atomic_t nr_iowait; + +#ifdef CONFIG_SMP + struct sched_domain *sd; + + /* For active balancing */ + int active_balance; + int push_cpu; + int cpu; /* cpu of this runqueue */ + + struct task_struct *migration_thread; struct list_head migration_queue; +#endif + unsigned long norm_time; + unsigned long idle_time; +#ifdef CONFIG_VSERVER_IDLETIME + int idle_skip; +#endif +#ifdef CONFIG_VSERVER_HARDCPU + struct list_head hold_queue; + unsigned long nr_onhold; + int idle_tokens; +#endif - atomic_t nr_iowait; +#ifdef CONFIG_SCHEDSTATS + /* latency stats */ + struct sched_info rq_sched_info; + + /* sys_sched_yield() stats */ + unsigned long yld_exp_empty; + unsigned long yld_act_empty; + unsigned long yld_both_empty; + unsigned long yld_cnt; + + /* schedule() stats */ + unsigned long sched_switch; + unsigned long sched_cnt; + unsigned long sched_goidle; + + /* try_to_wake_up() stats */ + unsigned long ttwu_cnt; + unsigned long ttwu_local; +#endif + struct lock_class_key rq_lock_key; }; -static DEFINE_PER_CPU(struct runqueue, runqueues); +static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp; + +static inline int cpu_of(struct rq *rq) +{ +#ifdef CONFIG_SMP + return rq->cpu; +#else + return 0; +#endif +} + +/* + * 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(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) -extern unsigned long __scheduling_functions_start_here; -extern unsigned long __scheduling_functions_end_here; -const unsigned long scheduling_functions_start_here = - (unsigned long)&__scheduling_functions_start_here; -const unsigned long scheduling_functions_end_here = - (unsigned long)&__scheduling_functions_end_here; - -/* - * Default context-switch locking: - */ #ifndef prepare_arch_switch -# define prepare_arch_switch(rq, next) do { } while (0) -# define finish_arch_switch(rq, next) spin_unlock_irq(&(rq)->lock) -# define task_running(rq, p) ((rq)->curr == (p)) +# define prepare_arch_switch(next) do { } while (0) +#endif +#ifndef finish_arch_switch +# define finish_arch_switch(prev) do { } while (0) #endif -#ifdef CONFIG_NUMA +#ifndef __ARCH_WANT_UNLOCKED_CTXSW +static inline int task_running(struct rq *rq, struct task_struct *p) +{ + return rq->curr == p; +} -/* - * Keep track of running tasks. - */ +static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) +{ +} + +static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) +{ +#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_); -static atomic_t node_nr_running[MAX_NUMNODES] ____cacheline_maxaligned_in_smp = - {[0 ...MAX_NUMNODES-1] = ATOMIC_INIT(0)}; + spin_unlock_irq(&rq->lock); +} -static inline void nr_running_init(struct runqueue *rq) +#else /* __ARCH_WANT_UNLOCKED_CTXSW */ +static inline int task_running(struct rq *rq, struct task_struct *p) { - rq->node_nr_running = &node_nr_running[0]; +#ifdef CONFIG_SMP + return p->oncpu; +#else + return rq->curr == p; +#endif } -static inline void nr_running_inc(runqueue_t *rq) +static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) { - atomic_inc(rq->node_nr_running); - rq->nr_running++; +#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->oncpu = 1; +#endif +#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW + spin_unlock_irq(&rq->lock); +#else + spin_unlock(&rq->lock); +#endif } -static inline void nr_running_dec(runqueue_t *rq) +static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) { - atomic_dec(rq->node_nr_running); - rq->nr_running--; +#ifdef CONFIG_SMP + /* + * After ->oncpu 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->oncpu = 0; +#endif +#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW + local_irq_enable(); +#endif } +#endif /* __ARCH_WANT_UNLOCKED_CTXSW */ -__init void node_nr_running_init(void) +/* + * __task_rq_lock - lock the runqueue a given task resides on. + * Must be called interrupts disabled. + */ +static inline struct rq *__task_rq_lock(struct task_struct *p) + __acquires(rq->lock) { - int i; + struct rq *rq; - for (i = 0; i < NR_CPUS; i++) { - if (cpu_possible(i)) - cpu_rq(i)->node_nr_running = - &node_nr_running[cpu_to_node(i)]; +repeat_lock_task: + rq = task_rq(p); + spin_lock(&rq->lock); + if (unlikely(rq != task_rq(p))) { + spin_unlock(&rq->lock); + goto repeat_lock_task; } + return rq; } -#else /* !CONFIG_NUMA */ - -# define nr_running_init(rq) do { } while (0) -# define nr_running_inc(rq) do { (rq)->nr_running++; } while (0) -# define nr_running_dec(rq) do { (rq)->nr_running--; } while (0) - -#endif /* CONFIG_NUMA */ - /* * task_rq_lock - lock the runqueue a given task resides on and disable * interrupts. Note the ordering: we can safely lookup the task_rq without * explicitly disabling preemption. */ -static inline runqueue_t *task_rq_lock(task_t *p, unsigned long *flags) +static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) + __acquires(rq->lock) { - struct runqueue *rq; + struct rq *rq; repeat_lock_task: local_irq_save(*flags); @@ -306,17 +423,153 @@ repeat_lock_task: return rq; } -static inline void task_rq_unlock(runqueue_t *rq, unsigned long *flags) +static inline void __task_rq_unlock(struct rq *rq) + __releases(rq->lock) +{ + spin_unlock(&rq->lock); +} + +static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) + __releases(rq->lock) { spin_unlock_irqrestore(&rq->lock, *flags); } +#ifdef CONFIG_SCHEDSTATS +/* + * bump this up when changing the output format or the meaning of an existing + * format, so that tools can adapt (or abort) + */ +#define SCHEDSTAT_VERSION 14 + +static int show_schedstat(struct seq_file *seq, void *v) +{ + int cpu; + + seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); + seq_printf(seq, "timestamp %lu\n", jiffies); + for_each_online_cpu(cpu) { + struct rq *rq = cpu_rq(cpu); +#ifdef CONFIG_SMP + struct sched_domain *sd; + int dcnt = 0; +#endif + + /* runqueue-specific stats */ + seq_printf(seq, + "cpu%d %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu", + cpu, rq->yld_both_empty, + rq->yld_act_empty, rq->yld_exp_empty, rq->yld_cnt, + rq->sched_switch, rq->sched_cnt, rq->sched_goidle, + rq->ttwu_cnt, rq->ttwu_local, + rq->rq_sched_info.cpu_time, + rq->rq_sched_info.run_delay, rq->rq_sched_info.pcnt); + + seq_printf(seq, "\n"); + +#ifdef CONFIG_SMP + /* domain-specific stats */ + preempt_disable(); + for_each_domain(cpu, sd) { + enum idle_type itype; + char mask_str[NR_CPUS]; + + cpumask_scnprintf(mask_str, NR_CPUS, sd->span); + seq_printf(seq, "domain%d %s", dcnt++, mask_str); + for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES; + itype++) { + seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu " + "%lu", + sd->lb_cnt[itype], + sd->lb_balanced[itype], + sd->lb_failed[itype], + sd->lb_imbalance[itype], + sd->lb_gained[itype], + sd->lb_hot_gained[itype], + sd->lb_nobusyq[itype], + sd->lb_nobusyg[itype]); + } + seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu %lu" + " %lu %lu %lu\n", + sd->alb_cnt, sd->alb_failed, sd->alb_pushed, + sd->sbe_cnt, sd->sbe_balanced, sd->sbe_pushed, + sd->sbf_cnt, sd->sbf_balanced, sd->sbf_pushed, + sd->ttwu_wake_remote, sd->ttwu_move_affine, + sd->ttwu_move_balance); + } + preempt_enable(); +#endif + } + return 0; +} + +static int schedstat_open(struct inode *inode, struct file *file) +{ + unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32); + char *buf = kmalloc(size, GFP_KERNEL); + struct seq_file *m; + int res; + + if (!buf) + return -ENOMEM; + res = single_open(file, show_schedstat, NULL); + if (!res) { + m = file->private_data; + m->buf = buf; + m->size = size; + } else + kfree(buf); + return res; +} + +const struct file_operations proc_schedstat_operations = { + .open = schedstat_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +/* + * Expects runqueue lock to be held for atomicity of update + */ +static inline void +rq_sched_info_arrive(struct rq *rq, unsigned long delta_jiffies) +{ + if (rq) { + rq->rq_sched_info.run_delay += delta_jiffies; + rq->rq_sched_info.pcnt++; + } +} + +/* + * Expects runqueue lock to be held for atomicity of update + */ +static inline void +rq_sched_info_depart(struct rq *rq, unsigned long delta_jiffies) +{ + if (rq) + rq->rq_sched_info.cpu_time += delta_jiffies; +} +# define schedstat_inc(rq, field) do { (rq)->field++; } while (0) +# define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0) +#else /* !CONFIG_SCHEDSTATS */ +static inline void +rq_sched_info_arrive(struct rq *rq, unsigned long delta_jiffies) +{} +static inline void +rq_sched_info_depart(struct rq *rq, unsigned long delta_jiffies) +{} +# define schedstat_inc(rq, field) do { } while (0) +# define schedstat_add(rq, field, amt) do { } while (0) +#endif + /* - * rq_lock - lock a given runqueue and disable interrupts. + * this_rq_lock - lock this runqueue and disable interrupts. */ -static inline runqueue_t *this_rq_lock(void) +static inline struct rq *this_rq_lock(void) + __acquires(rq->lock) { - runqueue_t *rq; + struct rq *rq; local_irq_disable(); rq = this_rq(); @@ -325,24 +578,128 @@ static inline runqueue_t *this_rq_lock(void) return rq; } -static inline void rq_unlock(runqueue_t *rq) +#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) +/* + * Called when a process is dequeued from the active array and given + * the cpu. We should note that with the exception of interactive + * tasks, the expired queue will become the active queue after the active + * queue is empty, without explicitly dequeuing and requeuing tasks in the + * expired queue. (Interactive tasks may be requeued directly to the + * active queue, thus delaying tasks in the expired queue from running; + * see scheduler_tick()). + * + * This function is only called from sched_info_arrive(), rather than + * dequeue_task(). Even though a task may be queued and dequeued multiple + * times as it is shuffled about, we're really interested in knowing how + * long it was from the *first* time it was queued to the time that it + * finally hit a cpu. + */ +static inline void sched_info_dequeued(struct task_struct *t) +{ + t->sched_info.last_queued = 0; +} + +/* + * Called when a task finally hits the cpu. We can now calculate how + * long it was waiting to run. We also note when it began so that we + * can keep stats on how long its timeslice is. + */ +static void sched_info_arrive(struct task_struct *t) { - spin_unlock_irq(&rq->lock); + unsigned long now = jiffies, delta_jiffies = 0; + + if (t->sched_info.last_queued) + delta_jiffies = now - t->sched_info.last_queued; + sched_info_dequeued(t); + t->sched_info.run_delay += delta_jiffies; + t->sched_info.last_arrival = now; + t->sched_info.pcnt++; + + rq_sched_info_arrive(task_rq(t), delta_jiffies); +} + +/* + * Called when a process is queued into either the active or expired + * array. The time is noted and later used to determine how long we + * had to wait for us to reach the cpu. Since the expired queue will + * become the active queue after active queue is empty, without dequeuing + * and requeuing any tasks, we are interested in queuing to either. It + * is unusual but not impossible for tasks to be dequeued and immediately + * requeued in the same or another array: this can happen in sched_yield(), + * set_user_nice(), and even load_balance() as it moves tasks from runqueue + * to runqueue. + * + * This function is only called from enqueue_task(), but also only updates + * the timestamp if it is already not set. It's assumed that + * sched_info_dequeued() will clear that stamp when appropriate. + */ +static inline void sched_info_queued(struct task_struct *t) +{ + if (unlikely(sched_info_on())) + if (!t->sched_info.last_queued) + t->sched_info.last_queued = jiffies; } +/* + * Called when a process ceases being the active-running process, either + * voluntarily or involuntarily. Now we can calculate how long we ran. + */ +static inline void sched_info_depart(struct task_struct *t) +{ + unsigned long delta_jiffies = jiffies - t->sched_info.last_arrival; + + t->sched_info.cpu_time += delta_jiffies; + rq_sched_info_depart(task_rq(t), delta_jiffies); +} + +/* + * Called when tasks are switched involuntarily due, typically, to expiring + * their time slice. (This may also be called when switching to or from + * the idle task.) We are only called when prev != next. + */ +static inline void +__sched_info_switch(struct task_struct *prev, struct task_struct *next) +{ + struct rq *rq = task_rq(prev); + + /* + * prev now departs the cpu. It's not interesting to record + * stats about how efficient we were at scheduling the idle + * process, however. + */ + if (prev != rq->idle) + sched_info_depart(prev); + + if (next != rq->idle) + sched_info_arrive(next); +} +static inline void +sched_info_switch(struct task_struct *prev, struct task_struct *next) +{ + if (unlikely(sched_info_on())) + __sched_info_switch(prev, next); +} +#else +#define sched_info_queued(t) do { } while (0) +#define sched_info_switch(t, next) do { } while (0) +#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */ + /* * Adding/removing a task to/from a priority array: */ -static inline void dequeue_task(struct task_struct *p, prio_array_t *array) +static void dequeue_task(struct task_struct *p, struct prio_array *array) { + BUG_ON(p->state & TASK_ONHOLD); array->nr_active--; list_del(&p->run_list); if (list_empty(array->queue + p->prio)) __clear_bit(p->prio, array->bitmap); } -static inline void enqueue_task(struct task_struct *p, prio_array_t *array) +static void enqueue_task(struct task_struct *p, struct prio_array *array) { + BUG_ON(p->state & TASK_ONHOLD); + sched_info_queued(p); list_add_tail(&p->run_list, array->queue + p->prio); __set_bit(p->prio, array->bitmap); array->nr_active++; @@ -350,7 +707,27 @@ static inline void enqueue_task(struct task_struct *p, prio_array_t *array) } /* - * effective_prio - return the priority that is based on the static + * Put task to the end of the run list without the overhead of dequeue + * followed by enqueue. + */ +static void requeue_task(struct task_struct *p, struct prio_array *array) +{ + BUG_ON(p->state & TASK_ONHOLD); + list_move_tail(&p->run_list, array->queue + p->prio); +} + +static inline void +enqueue_task_head(struct task_struct *p, struct prio_array *array) +{ + BUG_ON(p->state & TASK_ONHOLD); + list_add(&p->run_list, array->queue + p->prio); + __set_bit(p->prio, array->bitmap); + array->nr_active++; + p->array = array; +} + +/* + * __normal_prio - return the priority that is based on the static * priority but is modified by bonuses/penalties. * * We scale the actual sleep average [0 .... MAX_SLEEP_AVG] @@ -363,16 +740,18 @@ static inline void enqueue_task(struct task_struct *p, prio_array_t *array) * * Both properties are important to certain workloads. */ -static int effective_prio(task_t *p) + +static inline int __normal_prio(struct task_struct *p) { int bonus, prio; - if (rt_task(p)) - return p->prio; - bonus = CURRENT_BONUS(p) - MAX_BONUS / 2; prio = p->static_prio - bonus; + + /* adjust effective priority */ + prio = vx_adjust_prio(p, prio, MAX_USER_PRIO); + if (prio < MAX_RT_PRIO) prio = MAX_RT_PRIO; if (prio > MAX_PRIO-1) @@ -381,64 +760,183 @@ static int effective_prio(task_t *p) } /* - * __activate_task - move a task to the runqueue. + * 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. + */ + +/* + * Assume: static_prio_timeslice(NICE_TO_PRIO(0)) == DEF_TIMESLICE + * If static_prio_timeslice() is ever changed to break this assumption then + * this code will need modification */ -static inline void __activate_task(task_t *p, runqueue_t *rq) +#define TIME_SLICE_NICE_ZERO DEF_TIMESLICE +#define LOAD_WEIGHT(lp) \ + (((lp) * SCHED_LOAD_SCALE) / TIME_SLICE_NICE_ZERO) +#define PRIO_TO_LOAD_WEIGHT(prio) \ + LOAD_WEIGHT(static_prio_timeslice(prio)) +#define RTPRIO_TO_LOAD_WEIGHT(rp) \ + (PRIO_TO_LOAD_WEIGHT(MAX_RT_PRIO) + LOAD_WEIGHT(rp)) + +static void set_load_weight(struct task_struct *p) +{ + if (has_rt_policy(p)) { +#ifdef CONFIG_SMP + if (p == task_rq(p)->migration_thread) + /* + * The migration thread does the actual balancing. + * Giving its load any weight will skew balancing + * adversely. + */ + p->load_weight = 0; + else +#endif + p->load_weight = RTPRIO_TO_LOAD_WEIGHT(p->rt_priority); + } else + p->load_weight = PRIO_TO_LOAD_WEIGHT(p->static_prio); +} + +static inline void +inc_raw_weighted_load(struct rq *rq, const struct task_struct *p) +{ + rq->raw_weighted_load += p->load_weight; +} + +static inline void +dec_raw_weighted_load(struct rq *rq, const struct task_struct *p) +{ + rq->raw_weighted_load -= p->load_weight; +} + +static inline void inc_nr_running(struct task_struct *p, struct rq *rq) +{ + rq->nr_running++; + inc_raw_weighted_load(rq, p); +} + +static inline void dec_nr_running(struct task_struct *p, struct rq *rq) { - enqueue_task(p, rq->active); - nr_running_inc(rq); + rq->nr_running--; + dec_raw_weighted_load(rq, p); } -static void recalc_task_prio(task_t *p, unsigned long long now) +/* + * Calculate the expected normal priority: i.e. priority + * without taking RT-inheritance into account. Might be + * boosted by interactivity modifiers. Changes upon fork, + * setprio syscalls, and whenever the interactivity + * estimator recalculates. + */ +static inline int normal_prio(struct task_struct *p) { - unsigned long long __sleep_time = now - p->timestamp; - unsigned long sleep_time; + int prio; - if (__sleep_time > NS_MAX_SLEEP_AVG) - sleep_time = NS_MAX_SLEEP_AVG; + if (has_rt_policy(p)) + prio = MAX_RT_PRIO-1 - p->rt_priority; else - sleep_time = (unsigned long)__sleep_time; + prio = __normal_prio(p); + return prio; +} + +/* + * Calculate the current priority, i.e. the priority + * taken into account by the scheduler. This value might + * be boosted by RT tasks, or might be boosted by + * interactivity modifiers. Will be RT if the task got + * RT-boosted. If not then it returns p->normal_prio. + */ +static int effective_prio(struct task_struct *p) +{ + p->normal_prio = normal_prio(p); + /* + * If we are RT tasks or we were boosted to RT priority, + * keep the priority unchanged. Otherwise, update priority + * to the normal priority: + */ + if (!rt_prio(p->prio)) + return p->normal_prio; + return p->prio; +} + +#include "sched_mon.h" + + +/* + * __activate_task - move a task to the runqueue. + */ +static void __activate_task(struct task_struct *p, struct rq *rq) +{ + struct prio_array *target = rq->active; + + if (batch_task(p)) + target = rq->expired; + vxm_activate_task(p, rq); + enqueue_task(p, target); + inc_nr_running(p, rq); +} + +/* + * __activate_idle_task - move idle task to the _front_ of runqueue. + */ +static inline void __activate_idle_task(struct task_struct *p, struct rq *rq) +{ + vxm_activate_idle(p, rq); + enqueue_task_head(p, rq->active); + inc_nr_running(p, rq); +} + +/* + * Recalculate p->normal_prio and p->prio after having slept, + * updating the sleep-average too: + */ +static int recalc_task_prio(struct task_struct *p, unsigned long long now) +{ + /* Caller must always ensure 'now >= p->timestamp' */ + unsigned long sleep_time = now - p->timestamp; + + if (batch_task(p)) + sleep_time = 0; if (likely(sleep_time > 0)) { /* - * User tasks that sleep a long time are categorised as - * idle and will get just interactive status to stay active & - * prevent them suddenly becoming cpu hogs and starving - * other processes. + * This ceiling is set to the lowest priority that would allow + * a task to be reinserted into the active array on timeslice + * completion. */ - if (p->mm && p->activated != -1 && - sleep_time > INTERACTIVE_SLEEP(p)) { - p->sleep_avg = JIFFIES_TO_NS(MAX_SLEEP_AVG - - AVG_TIMESLICE); - if (!HIGH_CREDIT(p)) - p->interactive_credit++; - } else { + unsigned long ceiling = INTERACTIVE_SLEEP(p); + + if (p->mm && sleep_time > ceiling && p->sleep_avg < ceiling) { /* - * The lower the sleep avg a task has the more - * rapidly it will rise with sleep time. + * Prevents user tasks from achieving best priority + * with one single large enough sleep. */ - sleep_time *= (MAX_BONUS - CURRENT_BONUS(p)) ? : 1; - + p->sleep_avg = ceiling; /* - * Tasks with low interactive_credit are limited to - * one timeslice worth of sleep avg bonus. + * Using INTERACTIVE_SLEEP() as a ceiling places a + * nice(0) task 1ms sleep away from promotion, and + * gives it 700ms to round-robin with no chance of + * being demoted. This is more than generous, so + * mark this sleep as non-interactive to prevent the + * on-runqueue bonus logic from intervening should + * this task not receive cpu immediately. */ - if (LOW_CREDIT(p) && - sleep_time > JIFFIES_TO_NS(task_timeslice(p))) - sleep_time = JIFFIES_TO_NS(task_timeslice(p)); - + p->sleep_type = SLEEP_NONINTERACTIVE; + } else { /* - * Non high_credit tasks waking from uninterruptible - * sleep are limited in their sleep_avg rise as they - * are likely to be cpu hogs waiting on I/O + * Tasks waking from uninterruptible sleep are + * limited in their sleep_avg rise as they + * are likely to be waiting on I/O */ - if (p->activated == -1 && !HIGH_CREDIT(p) && p->mm) { - if (p->sleep_avg >= INTERACTIVE_SLEEP(p)) + if (p->sleep_type == SLEEP_NONINTERACTIVE && p->mm) { + if (p->sleep_avg >= ceiling) sleep_time = 0; else if (p->sleep_avg + sleep_time >= - INTERACTIVE_SLEEP(p)) { - p->sleep_avg = INTERACTIVE_SLEEP(p); - sleep_time = 0; + ceiling) { + p->sleep_avg = ceiling; + sleep_time = 0; } } @@ -452,15 +950,12 @@ static void recalc_task_prio(task_t *p, unsigned long long now) */ p->sleep_avg += sleep_time; - if (p->sleep_avg > NS_MAX_SLEEP_AVG) { - p->sleep_avg = NS_MAX_SLEEP_AVG; - if (!HIGH_CREDIT(p)) - p->interactive_credit++; - } } + if (p->sleep_avg > NS_MAX_SLEEP_AVG) + p->sleep_avg = NS_MAX_SLEEP_AVG; } - p->prio = effective_prio(p); + return effective_prio(p); } /* @@ -469,17 +964,41 @@ static void recalc_task_prio(task_t *p, unsigned long long now) * Update all the scheduling statistics stuff. (sleep average * calculation, priority modifiers, etc.) */ -static inline void activate_task(task_t *p, runqueue_t *rq) +static void activate_task(struct task_struct *p, struct rq *rq, int local) { - unsigned long long now = sched_clock(); + unsigned long long now; + + if (rt_task(p)) + goto out; + + now = sched_clock(); +#ifdef CONFIG_SMP + if (!local) { + /* Compensate for drifting sched_clock */ + struct rq *this_rq = this_rq(); + now = (now - this_rq->most_recent_timestamp) + + rq->most_recent_timestamp; + } +#endif + + /* + * Sleep time is in units of nanosecs, so shift by 20 to get a + * milliseconds-range estimation of the amount of time that the task + * spent sleeping: + */ + if (unlikely(prof_on == SLEEP_PROFILING)) { + if (p->state == TASK_UNINTERRUPTIBLE) + profile_hits(SLEEP_PROFILING, (void *)get_wchan(p), + (now - p->timestamp) >> 20); + } - recalc_task_prio(p, now); + p->prio = recalc_task_prio(p, now); /* * This checks to make sure it's not an uninterruptible task * that is now waking up. */ - if (!p->activated) { + if (p->sleep_type == SLEEP_NORMAL) { /* * Tasks which were woken up by interrupts (ie. hw events) * are most likely of interactive nature. So we give them @@ -488,32 +1007,41 @@ static inline void activate_task(task_t *p, runqueue_t *rq) * on a CPU, first time around: */ if (in_interrupt()) - p->activated = 2; + p->sleep_type = SLEEP_INTERRUPTED; else { /* * Normal first-time wakeups get a credit too for * on-runqueue time, but it will be weighted down: */ - p->activated = 1; + p->sleep_type = SLEEP_INTERACTIVE; } } p->timestamp = now; - +out: + vx_activate_task(p); __activate_task(p, rq); } /* - * deactivate_task - remove a task from the runqueue. + * __deactivate_task - remove a task from the runqueue. */ -static inline void deactivate_task(struct task_struct *p, runqueue_t *rq) +static void __deactivate_task(struct task_struct *p, struct rq *rq) { - nr_running_dec(rq); - if (p->state == TASK_UNINTERRUPTIBLE) - rq->nr_uninterruptible++; + dec_nr_running(p, rq); dequeue_task(p, p->array); + vxm_deactivate_task(p, rq); p->array = NULL; } +static inline +void deactivate_task(struct task_struct *p, struct rq *rq) +{ + vx_deactivate_task(p); + __deactivate_task(p, rq); +} + +#include "sched_hard.h" + /* * resched_task - mark a task 'to be rescheduled now'. * @@ -521,70 +1049,89 @@ static inline void deactivate_task(struct task_struct *p, runqueue_t *rq) * might also involve a cross-CPU call to trigger the scheduler on * the target CPU. */ -static inline void resched_task(task_t *p) -{ #ifdef CONFIG_SMP - int need_resched, nrpolling; - preempt_disable(); - /* minimise the chance of sending an interrupt to poll_idle() */ - nrpolling = test_tsk_thread_flag(p,TIF_POLLING_NRFLAG); - need_resched = test_and_set_tsk_thread_flag(p,TIF_NEED_RESCHED); - nrpolling |= test_tsk_thread_flag(p,TIF_POLLING_NRFLAG); +#ifndef tsk_is_polling +#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) +#endif - if (!need_resched && !nrpolling && (task_cpu(p) != smp_processor_id())) - smp_send_reschedule(task_cpu(p)); - preempt_enable(); +static void resched_task(struct task_struct *p) +{ + int cpu; + + assert_spin_locked(&task_rq(p)->lock); + + if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) + return; + + set_tsk_thread_flag(p, TIF_NEED_RESCHED); + + cpu = task_cpu(p); + if (cpu == smp_processor_id()) + return; + + /* NEED_RESCHED must be visible before we test polling */ + smp_mb(); + if (!tsk_is_polling(p)) + smp_send_reschedule(cpu); +} #else +static inline void resched_task(struct task_struct *p) +{ + assert_spin_locked(&task_rq(p)->lock); set_tsk_need_resched(p); -#endif } +#endif /** * task_curr - is this task currently executing on a CPU? * @p: the task in question. */ -inline int task_curr(task_t *p) +inline int task_curr(const struct task_struct *p) { return cpu_curr(task_cpu(p)) == p; } +/* Used instead of source_load when we know the type == 0 */ +unsigned long weighted_cpuload(const int cpu) +{ + return cpu_rq(cpu)->raw_weighted_load; +} + #ifdef CONFIG_SMP -typedef struct { +struct migration_req { struct list_head list; - task_t *task; + + struct task_struct *task; + int dest_cpu; + struct completion done; -} migration_req_t; +}; /* - * The task's runqueue lock must be held, and the new mask must be valid. + * The task's runqueue lock must be held. * Returns true if you have to wait for migration thread. */ -static int __set_cpus_allowed(task_t *p, cpumask_t new_mask, - migration_req_t *req) +static int +migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) { - runqueue_t *rq = task_rq(p); - - p->cpus_allowed = new_mask; - /* - * Can the task run on the task's current CPU? If not then - * migrate the thread off to a proper CPU. - */ - if (cpu_isset(task_cpu(p), new_mask)) - return 0; + struct rq *rq = task_rq(p); + vxm_migrate_task(p, rq, dest_cpu); /* * If the task is not on a runqueue (and not running), then * it is sufficient to simply update the task's cpu field. */ if (!p->array && !task_running(rq, p)) { - set_task_cpu(p, any_online_cpu(p->cpus_allowed)); + set_task_cpu(p, dest_cpu); return 0; } init_completion(&req->done); req->task = p; + req->dest_cpu = dest_cpu; list_add(&req->list, &rq->migration_queue); + return 1; } @@ -597,16 +1144,16 @@ static int __set_cpus_allowed(task_t *p, cpumask_t new_mask, * smp_call_function() if an IPI is sent by the same process we are * waiting to become inactive. */ -void wait_task_inactive(task_t * p) +void wait_task_inactive(struct task_struct *p) { unsigned long flags; - runqueue_t *rq; + struct rq *rq; int preempted; repeat: rq = task_rq_lock(p, &flags); /* Must be off runqueue entirely, not preempted. */ - if (unlikely(p->array)) { + if (unlikely(p->array || task_running(rq, p))) { /* If it's preempted, we yield. It could be a while. */ preempted = !task_running(rq, p); task_rq_unlock(rq, &flags); @@ -624,8 +1171,14 @@ repeat: * * Cause a process which is running on another CPU to enter * kernel-mode, without any delay. (to get signals handled.) + * + * NOTE: this function doesnt have to take the runqueue lock, + * because all it wants to ensure is that the remote task enters + * the kernel. If the IPI races and the task has been migrated + * to another CPU then no harm is done and the purpose has been + * achieved as well. */ -void kick_process(task_t *p) +void kick_process(struct task_struct *p) { int cpu; @@ -636,8 +1189,233 @@ void kick_process(task_t *p) preempt_enable(); } -EXPORT_SYMBOL_GPL(kick_process); +/* + * Return a low guess at the load of a migration-source cpu weighted + * according to the scheduling class and "nice" value. + * + * We want to under-estimate the load of migration sources, to + * balance conservatively. + */ +static inline unsigned long source_load(int cpu, int type) +{ + struct rq *rq = cpu_rq(cpu); + + if (type == 0) + return rq->raw_weighted_load; + + return min(rq->cpu_load[type-1], rq->raw_weighted_load); +} + +/* + * Return a high guess at the load of a migration-target cpu weighted + * according to the scheduling class and "nice" value. + */ +static inline unsigned long target_load(int cpu, int type) +{ + struct rq *rq = cpu_rq(cpu); + + if (type == 0) + return rq->raw_weighted_load; + + return max(rq->cpu_load[type-1], rq->raw_weighted_load); +} + +/* + * Return the average load per task on the cpu's run queue + */ +static inline unsigned long cpu_avg_load_per_task(int cpu) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long n = rq->nr_running; + + return n ? rq->raw_weighted_load / n : SCHED_LOAD_SCALE; +} + +/* + * find_idlest_group finds and returns the least busy CPU group within the + * domain. + */ +static struct sched_group * +find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) +{ + struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; + unsigned long min_load = ULONG_MAX, this_load = 0; + int load_idx = sd->forkexec_idx; + int imbalance = 100 + (sd->imbalance_pct-100)/2; + + do { + unsigned long load, avg_load; + int local_group; + int i; + + /* Skip over this group if it has no CPUs allowed */ + if (!cpus_intersects(group->cpumask, p->cpus_allowed)) + goto nextgroup; + + local_group = cpu_isset(this_cpu, group->cpumask); + + /* Tally up the load of all CPUs in the group */ + avg_load = 0; + + for_each_cpu_mask(i, group->cpumask) { + /* Bias balancing toward cpus of our domain */ + if (local_group) + load = source_load(i, load_idx); + else + load = target_load(i, load_idx); + + avg_load += load; + } + + /* Adjust by relative CPU power of the group */ + avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; + + if (local_group) { + this_load = avg_load; + this = group; + } else if (avg_load < min_load) { + min_load = avg_load; + idlest = group; + } +nextgroup: + group = group->next; + } while (group != sd->groups); + + if (!idlest || 100*this_load < imbalance*min_load) + return NULL; + return idlest; +} + +/* + * find_idlest_cpu - find the idlest cpu among the cpus in group. + */ +static int +find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) +{ + cpumask_t tmp; + unsigned long load, min_load = ULONG_MAX; + int idlest = -1; + int i; + + /* Traverse only the allowed CPUs */ + cpus_and(tmp, group->cpumask, p->cpus_allowed); + + for_each_cpu_mask(i, tmp) { + load = weighted_cpuload(i); + + if (load < min_load || (load == min_load && i == this_cpu)) { + min_load = load; + idlest = i; + } + } + + return idlest; +} + +/* + * sched_balance_self: balance the current task (running on cpu) in domains + * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and + * SD_BALANCE_EXEC. + * + * Balance, ie. select the least loaded group. + * + * Returns the target CPU number, or the same CPU if no balancing is needed. + * + * preempt must be disabled. + */ +static int sched_balance_self(int cpu, int flag) +{ + struct task_struct *t = current; + struct sched_domain *tmp, *sd = NULL; + + for_each_domain(cpu, tmp) { + /* + * If power savings logic is enabled for a domain, stop there. + */ + if (tmp->flags & SD_POWERSAVINGS_BALANCE) + break; + if (tmp->flags & flag) + sd = tmp; + } + + while (sd) { + cpumask_t span; + struct sched_group *group; + int new_cpu, weight; + + if (!(sd->flags & flag)) { + sd = sd->child; + continue; + } + + span = sd->span; + group = find_idlest_group(sd, t, cpu); + if (!group) { + sd = sd->child; + continue; + } + + new_cpu = find_idlest_cpu(group, t, cpu); + if (new_cpu == -1 || new_cpu == cpu) { + /* Now try balancing at a lower domain level of cpu */ + sd = sd->child; + continue; + } + + /* Now try balancing at a lower domain level of new_cpu */ + cpu = new_cpu; + sd = NULL; + weight = cpus_weight(span); + for_each_domain(cpu, tmp) { + if (weight <= cpus_weight(tmp->span)) + break; + if (tmp->flags & flag) + sd = tmp; + } + /* while loop will break here if sd == NULL */ + } + + return cpu; +} + +#endif /* CONFIG_SMP */ + +/* + * wake_idle() will wake a task on an idle cpu if task->cpu is + * not idle and an idle cpu is available. The span of cpus to + * search starts with cpus closest then further out as needed, + * so we always favor a closer, idle cpu. + * + * Returns the CPU we should wake onto. + */ +#if defined(ARCH_HAS_SCHED_WAKE_IDLE) +static int wake_idle(int cpu, struct task_struct *p) +{ + cpumask_t tmp; + struct sched_domain *sd; + int i; + + if (idle_cpu(cpu)) + return cpu; + for_each_domain(cpu, sd) { + if (sd->flags & SD_WAKE_IDLE) { + cpus_and(tmp, sd->span, p->cpus_allowed); + for_each_cpu_mask(i, tmp) { + if (idle_cpu(i)) + return i; + } + } + else + break; + } + return cpu; +} +#else +static inline int wake_idle(int cpu, struct task_struct *p) +{ + return cpu; +} #endif /*** @@ -654,73 +1432,199 @@ EXPORT_SYMBOL_GPL(kick_process); * * returns failure only if the task is already active. */ -static int try_to_wake_up(task_t * p, unsigned int state, int sync) +static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) { + int cpu, this_cpu, success = 0; unsigned long flags; - int success = 0; long old_state; - runqueue_t *rq; + struct rq *rq; +#ifdef CONFIG_SMP + struct sched_domain *sd, *this_sd = NULL; + unsigned long load, this_load; + int new_cpu; +#endif -repeat_lock_task: rq = task_rq_lock(p, &flags); old_state = p->state; - if (old_state & state) { - if (!p->array) { + + /* we need to unhold suspended tasks */ + if (old_state & TASK_ONHOLD) { + vx_unhold_task(p, rq); + old_state = p->state; + } + if (!(old_state & state)) + goto out; + + if (p->array) + goto out_running; + + cpu = task_cpu(p); + this_cpu = smp_processor_id(); + +#ifdef CONFIG_SMP + if (unlikely(task_running(rq, p))) + goto out_activate; + + new_cpu = cpu; + + schedstat_inc(rq, ttwu_cnt); + if (cpu == this_cpu) { + schedstat_inc(rq, ttwu_local); + goto out_set_cpu; + } + + for_each_domain(this_cpu, sd) { + if (cpu_isset(cpu, sd->span)) { + schedstat_inc(sd, ttwu_wake_remote); + this_sd = sd; + break; + } + } + + if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) + goto out_set_cpu; + + /* + * Check for affine wakeup and passive balancing possibilities. + */ + if (this_sd) { + int idx = this_sd->wake_idx; + unsigned int imbalance; + + imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; + + load = source_load(cpu, idx); + this_load = target_load(this_cpu, idx); + + new_cpu = this_cpu; /* Wake to this CPU if we can */ + + if (this_sd->flags & SD_WAKE_AFFINE) { + unsigned long tl = this_load; + unsigned long tl_per_task; + + tl_per_task = cpu_avg_load_per_task(this_cpu); + /* - * Fast-migrate the task if it's not running or runnable - * currently. Do not violate hard affinity. + * If sync wakeup then subtract the (maximum possible) + * effect of the currently running task from the load + * of the current CPU: */ - if (unlikely(sync && !task_running(rq, p) && - (task_cpu(p) != smp_processor_id()) && - cpu_isset(smp_processor_id(), - p->cpus_allowed) && - !cpu_is_offline(smp_processor_id()))) { - set_task_cpu(p, smp_processor_id()); - task_rq_unlock(rq, &flags); - goto repeat_lock_task; - } - if (old_state == TASK_UNINTERRUPTIBLE) { - rq->nr_uninterruptible--; + if (sync) + tl -= current->load_weight; + + if ((tl <= load && + tl + target_load(cpu, idx) <= tl_per_task) || + 100*(tl + p->load_weight) <= imbalance*load) { /* - * Tasks on involuntary sleep don't earn - * sleep_avg beyond just interactive state. + * This domain has SD_WAKE_AFFINE and + * p is cache cold in this domain, and + * there is no bad imbalance. */ - p->activated = -1; + schedstat_inc(this_sd, ttwu_move_affine); + goto out_set_cpu; } - if (sync && (task_cpu(p) == smp_processor_id())) - __activate_task(p, rq); - else { - activate_task(p, rq); - if (TASK_PREEMPTS_CURR(p, rq)) - resched_task(rq->curr); + } + + /* + * Start passive balancing when half the imbalance_pct + * limit is reached. + */ + if (this_sd->flags & SD_WAKE_BALANCE) { + if (imbalance*this_load <= 100*load) { + schedstat_inc(this_sd, ttwu_move_balance); + goto out_set_cpu; } - success = 1; } - p->state = TASK_RUNNING; } + + new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ +out_set_cpu: + new_cpu = wake_idle(new_cpu, p); + if (new_cpu != cpu) { + set_task_cpu(p, new_cpu); + task_rq_unlock(rq, &flags); + /* might preempt at this point */ + rq = task_rq_lock(p, &flags); + old_state = p->state; + if (!(old_state & state)) + goto out; + if (p->array) + goto out_running; + + this_cpu = smp_processor_id(); + cpu = task_cpu(p); + } + +out_activate: +#endif /* CONFIG_SMP */ + if (old_state == TASK_UNINTERRUPTIBLE) { + rq->nr_uninterruptible--; + vx_uninterruptible_dec(p); + /* + * Tasks on involuntary sleep don't earn + * sleep_avg beyond just interactive state. + */ + p->sleep_type = SLEEP_NONINTERACTIVE; + } else + + /* + * Tasks that have marked their sleep as noninteractive get + * woken up with their sleep average not weighted in an + * interactive way. + */ + if (old_state & TASK_NONINTERACTIVE) + p->sleep_type = SLEEP_NONINTERACTIVE; + + + activate_task(p, rq, cpu == this_cpu); + /* + * Sync wakeups (i.e. those types of wakeups where the waker + * has indicated that it will leave the CPU in short order) + * don't trigger a preemption, if the woken up task will run on + * this cpu. (in this case the 'I will reschedule' promise of + * the waker guarantees that the freshly woken up task is going + * to be considered on this CPU.) + */ + if (!sync || cpu != this_cpu) { + if (TASK_PREEMPTS_CURR(p, rq)) + resched_task(rq->curr); + } + success = 1; + +out_running: + p->state = TASK_RUNNING; +out: task_rq_unlock(rq, &flags); return success; } -int fastcall wake_up_process(task_t * p) + +int fastcall wake_up_process(struct task_struct *p) { - return try_to_wake_up(p, TASK_STOPPED | - TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); + return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | + TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); } - EXPORT_SYMBOL(wake_up_process); -int fastcall wake_up_state(task_t *p, unsigned int state) +int fastcall wake_up_state(struct task_struct *p, unsigned int state) { return try_to_wake_up(p, state, 0); } +static void task_running_tick(struct rq *rq, struct task_struct *p, int cpu); /* * Perform scheduler related setup for a newly forked process p. * p is forked by current. */ -void fastcall sched_fork(task_t *p) +void fastcall sched_fork(struct task_struct *p, int clone_flags) { + int cpu = get_cpu(); + +#ifdef CONFIG_SMP + cpu = sched_balance_self(cpu, SD_BALANCE_FORK); +#endif + set_task_cpu(p, cpu); + /* * We mark the process as running here, but have not actually * inserted it onto the runqueue yet. This guarantees that @@ -728,17 +1632,24 @@ void fastcall sched_fork(task_t *p) * event cannot wake it up and insert it on the runqueue either. */ p->state = TASK_RUNNING; + + /* + * Make sure we do not leak PI boosting priority to the child: + */ + p->prio = current->normal_prio; + INIT_LIST_HEAD(&p->run_list); p->array = NULL; - spin_lock_init(&p->switch_lock); +#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) + if (unlikely(sched_info_on())) + memset(&p->sched_info, 0, sizeof(p->sched_info)); +#endif +#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) + p->oncpu = 0; +#endif #ifdef CONFIG_PREEMPT - /* - * During context-switch we hold precisely one spinlock, which - * schedule_tail drops. (in the common case it's this_rq()->lock, - * but it also can be p->switch_lock.) So we compensate with a count - * of 1. Also, we want to start with kernel preemption disabled. - */ - p->thread_info->preempt_count = 1; + /* Want to start with kernel preemption disabled. */ + task_thread_info(p)->preempt_count = 1; #endif /* * Share the timeslice between parent and child, thus the @@ -754,60 +1665,101 @@ void fastcall sched_fork(task_t *p) p->first_time_slice = 1; current->time_slice >>= 1; p->timestamp = sched_clock(); - if (!current->time_slice) { + if (unlikely(!current->time_slice)) { /* - * This case is rare, it happens when the parent has only - * a single jiffy left from its timeslice. Taking the + * This case is rare, it happens when the parent has only + * a single jiffy left from its timeslice. Taking the * runqueue lock is not a problem. */ current->time_slice = 1; - preempt_disable(); - scheduler_tick(0, 0); - local_irq_enable(); - preempt_enable(); - } else - local_irq_enable(); + task_running_tick(cpu_rq(cpu), current, cpu); + } + local_irq_enable(); + put_cpu(); } /* - * wake_up_forked_process - wake up a freshly forked process. + * wake_up_new_task - wake up a newly created task for the first time. * * This function will do some initial scheduler statistics housekeeping - * that must be done for every newly created process. + * that must be done for every newly created context, then puts the task + * on the runqueue and wakes it. */ -void fastcall wake_up_forked_process(task_t * p) +void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) { + struct rq *rq, *this_rq; unsigned long flags; - runqueue_t *rq = task_rq_lock(current, &flags); + int this_cpu, cpu; + rq = task_rq_lock(p, &flags); BUG_ON(p->state != TASK_RUNNING); + this_cpu = smp_processor_id(); + cpu = task_cpu(p); /* * We decrease the sleep average of forking parents * and children as well, to keep max-interactive tasks - * from forking tasks that are max-interactive. + * from forking tasks that are max-interactive. The parent + * (current) is done further down, under its lock. */ - current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) * - PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); - p->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(p) * CHILD_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); - p->interactive_credit = 0; - p->prio = effective_prio(p); - set_task_cpu(p, smp_processor_id()); - if (unlikely(!current->array)) + vx_activate_task(p); + if (likely(cpu == this_cpu)) { + if (!(clone_flags & CLONE_VM)) { + /* + * The VM isn't cloned, so we're in a good position to + * do child-runs-first in anticipation of an exec. This + * usually avoids a lot of COW overhead. + */ + if (unlikely(!current->array)) + __activate_task(p, rq); + else { + p->prio = current->prio; + BUG_ON(p->state & TASK_ONHOLD); + p->normal_prio = current->normal_prio; + list_add_tail(&p->run_list, ¤t->run_list); + p->array = current->array; + p->array->nr_active++; + inc_nr_running(p, rq); + } + set_need_resched(); + } else + /* Run child last */ + __activate_task(p, rq); + /* + * We skip the following code due to cpu == this_cpu + * + * task_rq_unlock(rq, &flags); + * this_rq = task_rq_lock(current, &flags); + */ + this_rq = rq; + } else { + this_rq = cpu_rq(this_cpu); + + /* + * Not the local CPU - must adjust timestamp. This should + * get optimised away in the !CONFIG_SMP case. + */ + p->timestamp = (p->timestamp - this_rq->most_recent_timestamp) + + rq->most_recent_timestamp; __activate_task(p, rq); - else { - p->prio = current->prio; - list_add_tail(&p->run_list, ¤t->run_list); - p->array = current->array; - p->array->nr_active++; - nr_running_inc(rq); + if (TASK_PREEMPTS_CURR(p, rq)) + resched_task(rq->curr); + + /* + * Parent and child are on different CPUs, now get the + * parent runqueue to update the parent's ->sleep_avg: + */ + task_rq_unlock(rq, &flags); + this_rq = task_rq_lock(current, &flags); } - task_rq_unlock(rq, &flags); + current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) * + PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); + task_rq_unlock(this_rq, &flags); } /* @@ -819,23 +1771,21 @@ void fastcall wake_up_forked_process(task_t * p) * artificially, because any timeslice recovered here * was given away by the parent in the first place.) */ -void fastcall sched_exit(task_t * p) +void fastcall sched_exit(struct task_struct *p) { unsigned long flags; - runqueue_t *rq; + struct rq *rq; - local_irq_save(flags); - if (p->first_time_slice) { - p->parent->time_slice += p->time_slice; - if (unlikely(p->parent->time_slice > MAX_TIMESLICE)) - p->parent->time_slice = MAX_TIMESLICE; - } - local_irq_restore(flags); /* * If the child was a (relative-) CPU hog then decrease * the sleep_avg of the parent as well. */ rq = task_rq_lock(p->parent, &flags); + if (p->first_time_slice && task_cpu(p) == task_cpu(p->parent)) { + p->parent->time_slice += p->time_slice; + if (unlikely(p->parent->time_slice > task_timeslice(p))) + p->parent->time_slice = task_timeslice(p); + } if (p->sleep_avg < p->parent->sleep_avg) p->parent->sleep_avg = p->parent->sleep_avg / (EXIT_WEIGHT + 1) * EXIT_WEIGHT + p->sleep_avg / @@ -844,53 +1794,86 @@ void fastcall sched_exit(task_t * p) } /** - * finish_task_switch - clean up after a task-switch - * @prev: the thread we just switched away from. + * prepare_task_switch - prepare to switch tasks + * @rq: the runqueue preparing to switch + * @next: the task we are going to switch to. * - * We enter this with the runqueue still locked, and finish_arch_switch() - * will unlock it along with doing any other architecture-specific cleanup - * actions. + * This is called with the rq lock held and interrupts off. It must + * be paired with a subsequent finish_task_switch after the context + * switch. + * + * prepare_task_switch sets up locking and calls architecture specific + * hooks. + */ +static inline void prepare_task_switch(struct rq *rq, struct task_struct *next) +{ + prepare_lock_switch(rq, next); + prepare_arch_switch(next); +} + +/** + * finish_task_switch - clean up after a task-switch + * @rq: runqueue associated with task-switch + * @prev: the thread we just switched away from. + * + * finish_task_switch must be called after the context switch, paired + * with a prepare_task_switch call before the context switch. + * finish_task_switch will reconcile locking set up by prepare_task_switch, + * and do any other architecture-specific cleanup actions. * * Note that we may have delayed dropping an mm in context_switch(). If * so, we finish that here outside of the runqueue lock. (Doing it * with the lock held can cause deadlocks; see schedule() for * details.) */ -static inline void finish_task_switch(task_t *prev) +static inline void finish_task_switch(struct rq *rq, struct task_struct *prev) + __releases(rq->lock) { - runqueue_t *rq = this_rq(); struct mm_struct *mm = rq->prev_mm; - unsigned long prev_task_flags; + long prev_state; rq->prev_mm = NULL; /* * A task struct has one reference for the use as "current". - * If a task dies, then it sets TASK_ZOMBIE in tsk->state and calls - * schedule one last time. The schedule call will never return, - * and the scheduled task must drop that reference. - * The test for TASK_ZOMBIE must occur while the runqueue locks are + * If a task dies, then it sets TASK_DEAD in tsk->state and calls + * schedule one last time. The schedule call will never return, and + * the scheduled task must drop that reference. + * The test for TASK_DEAD must occur while the runqueue locks are * still held, otherwise prev could be scheduled on another cpu, die * there before we look at prev->state, and then the reference would * be dropped twice. - * Manfred Spraul + * Manfred Spraul */ - prev_task_flags = prev->flags; - finish_arch_switch(rq, prev); + prev_state = prev->state; + finish_arch_switch(prev); + finish_lock_switch(rq, prev); if (mm) mmdrop(mm); - if (unlikely(prev_task_flags & PF_DEAD)) + if (unlikely(prev_state == TASK_DEAD)) { + /* + * Remove function-return probe instances associated with this + * task and put them back on the free list. + */ + kprobe_flush_task(prev); put_task_struct(prev); + } } /** * schedule_tail - first thing a freshly forked thread must call. * @prev: the thread we just switched away from. */ -asmlinkage void schedule_tail(task_t *prev) +asmlinkage void schedule_tail(struct task_struct *prev) + __releases(rq->lock) { - finish_task_switch(prev); + struct rq *rq = this_rq(); + finish_task_switch(rq, prev); +#ifdef __ARCH_WANT_UNLOCKED_CTXSW + /* In this case, finish_task_switch does not reenable preemption */ + preempt_enable(); +#endif if (current->set_child_tid) put_user(current->pid, current->set_child_tid); } @@ -899,24 +1882,34 @@ asmlinkage void schedule_tail(task_t *prev) * context_switch - switch to the new MM and the new * thread's register state. */ -static inline -task_t * context_switch(runqueue_t *rq, task_t *prev, task_t *next) +static inline struct task_struct * +context_switch(struct rq *rq, struct task_struct *prev, + struct task_struct *next) { struct mm_struct *mm = next->mm; struct mm_struct *oldmm = prev->active_mm; - if (unlikely(!mm)) { + if (!mm) { next->active_mm = oldmm; atomic_inc(&oldmm->mm_count); enter_lazy_tlb(oldmm, next); } else switch_mm(oldmm, mm, next); - if (unlikely(!prev->mm)) { + if (!prev->mm) { prev->active_mm = NULL; WARN_ON(rq->prev_mm); rq->prev_mm = oldmm; } + /* + * Since the runqueue lock will be released by the next + * task (which is an invalid locking op but in the case + * of the scheduler it's an obvious special-case), so we + * do an early lockdep release here: + */ +#ifndef __ARCH_WANT_UNLOCKED_CTXSW + spin_release(&rq->lock.dep_map, 1, _THIS_IP_); +#endif /* Here we just switch the register state and the stack. */ switch_to(prev, next, prev); @@ -935,7 +1928,7 @@ unsigned long nr_running(void) { unsigned long i, sum = 0; - for (i = 0; i < NR_CPUS; i++) + for_each_online_cpu(i) sum += cpu_rq(i)->nr_running; return sum; @@ -945,17 +1938,25 @@ unsigned long nr_uninterruptible(void) { unsigned long i, sum = 0; - for_each_cpu(i) + for_each_possible_cpu(i) sum += cpu_rq(i)->nr_uninterruptible; + /* + * Since we read the counters lockless, it might be slightly + * inaccurate. Do not allow it to go below zero though: + */ + if (unlikely((long)sum < 0)) + sum = 0; + return sum; } unsigned long long nr_context_switches(void) { - unsigned long long i, sum = 0; + int i; + unsigned long long sum = 0; - for_each_cpu(i) + for_each_possible_cpu(i) sum += cpu_rq(i)->nr_switches; return sum; @@ -965,23 +1966,53 @@ unsigned long nr_iowait(void) { unsigned long i, sum = 0; - for_each_cpu(i) + for_each_possible_cpu(i) sum += atomic_read(&cpu_rq(i)->nr_iowait); return sum; } +unsigned long nr_active(void) +{ + unsigned long i, running = 0, uninterruptible = 0; + + for_each_online_cpu(i) { + running += cpu_rq(i)->nr_running; + uninterruptible += cpu_rq(i)->nr_uninterruptible; + } + + if (unlikely((long)uninterruptible < 0)) + uninterruptible = 0; + + return running + uninterruptible; +} + +#ifdef CONFIG_SMP + +/* + * Is this task likely cache-hot: + */ +static inline int +task_hot(struct task_struct *p, unsigned long long now, struct sched_domain *sd) +{ + return (long long)(now - p->last_ran) < (long long)sd->cache_hot_time; +} + /* * 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(runqueue_t *rq1, runqueue_t *rq2) +static void double_rq_lock(struct rq *rq1, struct rq *rq2) + __acquires(rq1->lock) + __acquires(rq2->lock) { - if (rq1 == rq2) + BUG_ON(!irqs_disabled()); + if (rq1 == rq2) { spin_lock(&rq1->lock); - else { + __acquire(rq2->lock); /* Fake it out ;) */ + } else { if (rq1 < rq2) { spin_lock(&rq1->lock); spin_lock(&rq2->lock); @@ -998,329 +2029,186 @@ static inline void double_rq_lock(runqueue_t *rq1, runqueue_t *rq2) * Note this does not restore interrupts like task_rq_unlock, * you need to do so manually after calling. */ -static inline void double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2) +static void double_rq_unlock(struct rq *rq1, struct rq *rq2) + __releases(rq1->lock) + __releases(rq2->lock) { spin_unlock(&rq1->lock); if (rq1 != rq2) spin_unlock(&rq2->lock); -} - -#ifdef CONFIG_NUMA -/* - * If dest_cpu is allowed for this process, migrate the task to it. - * This is accomplished by forcing the cpu_allowed mask to only - * allow dest_cpu, which will force the cpu onto dest_cpu. Then - * the cpu_allowed mask is restored. - */ -static void sched_migrate_task(task_t *p, int dest_cpu) -{ - runqueue_t *rq; - migration_req_t req; - unsigned long flags; - cpumask_t old_mask, new_mask = cpumask_of_cpu(dest_cpu); - - lock_cpu_hotplug(); - rq = task_rq_lock(p, &flags); - old_mask = p->cpus_allowed; - if (!cpu_isset(dest_cpu, old_mask) || !cpu_online(dest_cpu)) - goto out; - - /* force the process onto the specified CPU */ - if (__set_cpus_allowed(p, new_mask, &req)) { - /* Need to wait for migration thread. */ - task_rq_unlock(rq, &flags); - wake_up_process(rq->migration_thread); - wait_for_completion(&req.done); - - /* If we raced with sys_sched_setaffinity, don't - * restore mask. */ - rq = task_rq_lock(p, &flags); - if (likely(cpus_equal(p->cpus_allowed, new_mask))) { - /* Restore old mask: won't need migration - * thread, since current cpu is allowed. */ - BUG_ON(__set_cpus_allowed(p, old_mask, NULL)); - } - } -out: - task_rq_unlock(rq, &flags); - unlock_cpu_hotplug(); -} - -/* - * Find the least loaded CPU. Slightly favor the current CPU by - * setting its runqueue length as the minimum to start. - */ -static int sched_best_cpu(struct task_struct *p) -{ - int i, minload, load, best_cpu, node = 0; - cpumask_t cpumask; - - best_cpu = task_cpu(p); - if (cpu_rq(best_cpu)->nr_running <= 2) - return best_cpu; - - minload = 10000000; - for_each_node_with_cpus(i) { - /* - * Node load is always divided by nr_cpus_node to normalise - * load values in case cpu count differs from node to node. - * We first multiply node_nr_running by 10 to get a little - * better resolution. - */ - load = 10 * atomic_read(&node_nr_running[i]) / nr_cpus_node(i); - if (load < minload) { - minload = load; - node = i; - } - } - - minload = 10000000; - cpumask = node_to_cpumask(node); - for (i = 0; i < NR_CPUS; ++i) { - if (!cpu_isset(i, cpumask)) - continue; - if (cpu_rq(i)->nr_running < minload) { - best_cpu = i; - minload = cpu_rq(i)->nr_running; - } - } - return best_cpu; -} - -void sched_balance_exec(void) -{ - int new_cpu; - - if (numnodes > 1) { - new_cpu = sched_best_cpu(current); - if (new_cpu != smp_processor_id()) - sched_migrate_task(current, new_cpu); - } + else + __release(rq2->lock); } /* - * Find the busiest node. All previous node loads contribute with a - * geometrically deccaying weight to the load measure: - * load_{t} = load_{t-1}/2 + nr_node_running_{t} - * This way sudden load peaks are flattened out a bit. - * Node load is divided by nr_cpus_node() in order to compare nodes - * of different cpu count but also [first] multiplied by 10 to - * provide better resolution. + * double_lock_balance - lock the busiest runqueue, this_rq is locked already. */ -static int find_busiest_node(int this_node) +static void double_lock_balance(struct rq *this_rq, struct rq *busiest) + __releases(this_rq->lock) + __acquires(busiest->lock) + __acquires(this_rq->lock) { - int i, node = -1, load, this_load, maxload; - - if (!nr_cpus_node(this_node)) - return node; - this_load = maxload = (this_rq()->prev_node_load[this_node] >> 1) - + (10 * atomic_read(&node_nr_running[this_node]) - / nr_cpus_node(this_node)); - this_rq()->prev_node_load[this_node] = this_load; - for_each_node_with_cpus(i) { - if (i == this_node) - continue; - load = (this_rq()->prev_node_load[i] >> 1) - + (10 * atomic_read(&node_nr_running[i]) - / nr_cpus_node(i)); - this_rq()->prev_node_load[i] = load; - if (load > maxload && (100*load > NODE_THRESHOLD*this_load)) { - maxload = load; - node = i; - } + if (unlikely(!irqs_disabled())) { + /* printk() doesn't work good under rq->lock */ + spin_unlock(&this_rq->lock); + BUG_ON(1); } - return node; -} - -#endif /* CONFIG_NUMA */ - -#ifdef CONFIG_SMP - -/* - * double_lock_balance - lock the busiest runqueue - * - * this_rq is locked already. Recalculate nr_running if we have to - * drop the runqueue lock. - */ -static inline -unsigned int double_lock_balance(runqueue_t *this_rq, runqueue_t *busiest, - int this_cpu, int idle, - unsigned int nr_running) -{ if (unlikely(!spin_trylock(&busiest->lock))) { if (busiest < this_rq) { spin_unlock(&this_rq->lock); spin_lock(&busiest->lock); spin_lock(&this_rq->lock); - /* Need to recalculate nr_running */ - if (idle || (this_rq->nr_running > - this_rq->prev_cpu_load[this_cpu])) - nr_running = this_rq->nr_running; - else - nr_running = this_rq->prev_cpu_load[this_cpu]; } else spin_lock(&busiest->lock); } - return nr_running; } /* - * find_busiest_queue - find the busiest runqueue among the cpus in cpumask. + * If dest_cpu is allowed for this process, migrate the task to it. + * This is accomplished by forcing the cpu_allowed mask to only + * allow dest_cpu, which will force the cpu onto dest_cpu. Then + * the cpu_allowed mask is restored. */ -static inline -runqueue_t *find_busiest_queue(runqueue_t *this_rq, int this_cpu, int idle, - int *imbalance, cpumask_t cpumask) +static void sched_migrate_task(struct task_struct *p, int dest_cpu) { - int nr_running, load, max_load, i; - runqueue_t *busiest, *rq_src; - - /* - * We search all runqueues to find the most busy one. - * We do this lockless to reduce cache-bouncing overhead, - * we re-check the 'best' source CPU later on again, with - * the lock held. - * - * We fend off statistical fluctuations in runqueue lengths by - * saving the runqueue length (as seen by the balancing CPU) during - * the previous load-balancing operation and using the smaller one - * of the current and saved lengths. If a runqueue is long enough - * for a longer amount of time then we recognize it and pull tasks - * from it. - * - * The 'current runqueue length' is a statistical maximum variable, - * for that one we take the longer one - to avoid fluctuations in - * the other direction. So for a load-balance to happen it needs - * stable long runqueue on the target CPU and stable short runqueue - * on the local runqueue. - * - * We make an exception if this CPU is about to become idle - in - * that case we are less picky about moving a task across CPUs and - * take what can be taken. - */ - if (idle || (this_rq->nr_running > this_rq->prev_cpu_load[this_cpu])) - nr_running = this_rq->nr_running; - else - nr_running = this_rq->prev_cpu_load[this_cpu]; - - busiest = NULL; - max_load = 1; - for (i = 0; i < NR_CPUS; i++) { - if (!cpu_isset(i, cpumask)) - continue; - - rq_src = cpu_rq(i); - if (idle || (rq_src->nr_running < this_rq->prev_cpu_load[i])) - load = rq_src->nr_running; - else - load = this_rq->prev_cpu_load[i]; - this_rq->prev_cpu_load[i] = rq_src->nr_running; - - if ((load > max_load) && (rq_src != this_rq)) { - busiest = rq_src; - max_load = load; - } - } + struct migration_req req; + unsigned long flags; + struct rq *rq; - if (likely(!busiest)) + rq = task_rq_lock(p, &flags); + if (!cpu_isset(dest_cpu, p->cpus_allowed) + || unlikely(cpu_is_offline(dest_cpu))) goto out; - *imbalance = max_load - nr_running; + /* force the process onto the specified CPU */ + if (migrate_task(p, dest_cpu, &req)) { + /* Need to wait for migration thread (might exit: take ref). */ + struct task_struct *mt = rq->migration_thread; - /* It needs an at least ~25% imbalance to trigger balancing. */ - if (!idle && ((*imbalance)*4 < max_load)) { - busiest = NULL; - goto out; - } + get_task_struct(mt); + task_rq_unlock(rq, &flags); + wake_up_process(mt); + put_task_struct(mt); + wait_for_completion(&req.done); - nr_running = double_lock_balance(this_rq, busiest, this_cpu, - idle, nr_running); - /* - * Make sure nothing changed since we checked the - * runqueue length. - */ - if (busiest->nr_running <= nr_running) { - spin_unlock(&busiest->lock); - busiest = NULL; + return; } out: - return busiest; + task_rq_unlock(rq, &flags); +} + +/* + * sched_exec - execve() is a valuable balancing opportunity, because at + * this point the task has the smallest effective memory and cache footprint. + */ +void sched_exec(void) +{ + int new_cpu, this_cpu = get_cpu(); + new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); + put_cpu(); + if (new_cpu != this_cpu) + sched_migrate_task(current, new_cpu); } /* * pull_task - move a task from a remote runqueue to the local runqueue. * Both runqueues must be locked. */ -static inline -void pull_task(runqueue_t *src_rq, prio_array_t *src_array, task_t *p, - runqueue_t *this_rq, int this_cpu) +static void pull_task(struct rq *src_rq, struct prio_array *src_array, + struct task_struct *p, struct rq *this_rq, + struct prio_array *this_array, int this_cpu) { dequeue_task(p, src_array); - nr_running_dec(src_rq); + dec_nr_running(p, src_rq); set_task_cpu(p, this_cpu); - nr_running_inc(this_rq); - enqueue_task(p, this_rq->active); - p->timestamp = sched_clock() - - (src_rq->timestamp_last_tick - p->timestamp); + inc_nr_running(p, this_rq); + enqueue_task(p, this_array); + p->timestamp = (p->timestamp - src_rq->most_recent_timestamp) + + this_rq->most_recent_timestamp; /* * Note that idle threads have a prio of MAX_PRIO, for this test * to be always true for them. */ if (TASK_PREEMPTS_CURR(p, this_rq)) - set_need_resched(); + resched_task(this_rq->curr); } /* * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? */ -static inline -int can_migrate_task(task_t *tsk, runqueue_t *rq, int this_cpu, int idle) +static +int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, + struct sched_domain *sd, enum idle_type idle, + int *all_pinned) { - unsigned long delta = rq->timestamp_last_tick - tsk->timestamp; - /* * We do not migrate tasks that are: * 1) running (obviously), or * 2) cannot be migrated to this CPU due to cpus_allowed, or * 3) are cache-hot on their current CPU. */ - if (task_running(rq, tsk)) + if (!cpu_isset(this_cpu, p->cpus_allowed)) return 0; - if (!cpu_isset(this_cpu, tsk->cpus_allowed)) + *all_pinned = 0; + + if (task_running(rq, p)) return 0; - if (!idle && (delta <= JIFFIES_TO_NS(cache_decay_ticks))) + + /* + * Aggressive migration if: + * 1) task is cache cold, or + * 2) too many balance attempts have failed. + */ + + if (sd->nr_balance_failed > sd->cache_nice_tries) { +#ifdef CONFIG_SCHEDSTATS + if (task_hot(p, rq->most_recent_timestamp, sd)) + schedstat_inc(sd, lb_hot_gained[idle]); +#endif + return 1; + } + + if (task_hot(p, rq->most_recent_timestamp, sd)) return 0; return 1; } +#define rq_best_prio(rq) min((rq)->curr->prio, (rq)->best_expired_prio) + /* - * Current runqueue is empty, or rebalance tick: if there is an - * inbalance (current runqueue is too short) then pull from - * busiest runqueue(s). + * move_tasks tries to move up to max_nr_move tasks and max_load_move weighted + * load from busiest to this_rq, as part of a balancing operation within + * "domain". Returns the number of tasks moved. * - * We call this with the current runqueue locked, - * irqs disabled. + * Called with both runqueues locked. */ -static void load_balance(runqueue_t *this_rq, int idle, cpumask_t cpumask) +static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, + unsigned long max_nr_move, unsigned long max_load_move, + struct sched_domain *sd, enum idle_type idle, + int *all_pinned) { - int imbalance, idx, this_cpu = smp_processor_id(); - runqueue_t *busiest; - prio_array_t *array; + int idx, pulled = 0, pinned = 0, this_best_prio, best_prio, + best_prio_seen, skip_for_load; + struct prio_array *array, *dst_array; struct list_head *head, *curr; - task_t *tmp; - - if (cpu_is_offline(this_cpu)) - goto out; + struct task_struct *tmp; + long rem_load_move; - busiest = find_busiest_queue(this_rq, this_cpu, idle, - &imbalance, cpumask); - if (!busiest) + if (max_nr_move == 0 || max_load_move == 0) goto out; + rem_load_move = max_load_move; + pinned = 1; + this_best_prio = rq_best_prio(this_rq); + best_prio = rq_best_prio(busiest); /* - * We only want to steal a number of tasks equal to 1/2 the imbalance, - * otherwise we'll just shift the imbalance to the new queue: + * Enable handling of the case where there is more than one task + * with the best priority. If the current running task is one + * of those with prio==best_prio we know it won't be moved + * and therefore it's safe to override the skip (based on load) of + * any task we find with that prio. */ - imbalance /= 2; + best_prio_seen = best_prio == busiest->curr->prio; /* * We first consider expired tasks. Those will likely not be @@ -1328,10 +2216,13 @@ static void load_balance(runqueue_t *this_rq, int idle, cpumask_t cpumask) * be cache-cold, thus switching CPUs has the least effect * on them. */ - if (busiest->expired->nr_active) + if (busiest->expired->nr_active) { array = busiest->expired; - else + dst_array = this_rq->expired; + } else { array = busiest->active; + dst_array = this_rq->active; + } new_array: /* Start searching at priority 0: */ @@ -1342,1621 +2233,4769 @@ skip_bitmap: else idx = find_next_bit(array->bitmap, MAX_PRIO, idx); if (idx >= MAX_PRIO) { - if (array == busiest->expired) { + if (array == busiest->expired && busiest->active->nr_active) { array = busiest->active; + dst_array = this_rq->active; goto new_array; } - goto out_unlock; + goto out; } head = array->queue + idx; curr = head->prev; skip_queue: - tmp = list_entry(curr, task_t, run_list); + tmp = list_entry(curr, struct task_struct, run_list); curr = curr->prev; - if (!can_migrate_task(tmp, busiest, this_cpu, idle)) { + /* + * To help distribute high priority tasks accross CPUs we don't + * skip a task if it will be the highest priority task (i.e. smallest + * prio value) on its new queue regardless of its load weight + */ + skip_for_load = tmp->load_weight > rem_load_move; + if (skip_for_load && idx < this_best_prio) + skip_for_load = !best_prio_seen && idx == best_prio; + if (skip_for_load || + !can_migrate_task(tmp, busiest, this_cpu, sd, idle, &pinned)) { + + best_prio_seen |= idx == best_prio; if (curr != head) goto skip_queue; idx++; goto skip_bitmap; } - pull_task(busiest, array, tmp, this_rq, this_cpu); - /* Only migrate one task if we are idle */ - if (!idle && --imbalance) { + pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu); + pulled++; + rem_load_move -= tmp->load_weight; + + /* + * We only want to steal up to the prescribed number of tasks + * and the prescribed amount of weighted load. + */ + if (pulled < max_nr_move && rem_load_move > 0) { + if (idx < this_best_prio) + this_best_prio = idx; if (curr != head) goto skip_queue; idx++; goto skip_bitmap; } -out_unlock: - spin_unlock(&busiest->lock); out: - ; + /* + * Right now, this is the only place pull_task() is called, + * so we can safely collect pull_task() stats here rather than + * inside pull_task(). + */ + schedstat_add(sd, lb_gained[idle], pulled); + + if (all_pinned) + *all_pinned = pinned; + return pulled; } /* - * One of the idle_cpu_tick() and busy_cpu_tick() functions will - * get called every timer tick, on every CPU. Our balancing action - * frequency and balancing agressivity depends on whether the CPU is - * idle or not. - * - * busy-rebalance every 200 msecs. idle-rebalance every 1 msec. (or on - * systems with HZ=100, every 10 msecs.) - * - * On NUMA, do a node-rebalance every 400 msecs. + * find_busiest_group finds and returns the busiest CPU group within the + * domain. It calculates and returns the amount of weighted load which + * should be moved to restore balance via the imbalance parameter. */ -#define IDLE_REBALANCE_TICK (HZ/1000 ?: 1) -#define BUSY_REBALANCE_TICK (HZ/5 ?: 1) -#define IDLE_NODE_REBALANCE_TICK (IDLE_REBALANCE_TICK * 5) -#define BUSY_NODE_REBALANCE_TICK (BUSY_REBALANCE_TICK * 2) - -#ifdef CONFIG_NUMA -static void balance_node(runqueue_t *this_rq, int idle, int this_cpu) +static struct sched_group * +find_busiest_group(struct sched_domain *sd, int this_cpu, + unsigned long *imbalance, enum idle_type idle, int *sd_idle, + cpumask_t *cpus, int *balance) { - int node = find_busiest_node(cpu_to_node(this_cpu)); - - if (node >= 0) { - cpumask_t cpumask = node_to_cpumask(node); - cpu_set(this_cpu, cpumask); - spin_lock(&this_rq->lock); - load_balance(this_rq, idle, cpumask); - spin_unlock(&this_rq->lock); - } -} + struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; + unsigned long max_load, avg_load, total_load, this_load, total_pwr; + unsigned long max_pull; + unsigned long busiest_load_per_task, busiest_nr_running; + unsigned long this_load_per_task, this_nr_running; + int load_idx; +#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) + int power_savings_balance = 1; + unsigned long leader_nr_running = 0, min_load_per_task = 0; + unsigned long min_nr_running = ULONG_MAX; + struct sched_group *group_min = NULL, *group_leader = NULL; #endif -static void rebalance_tick(runqueue_t *this_rq, int idle) -{ -#ifdef CONFIG_NUMA - int this_cpu = smp_processor_id(); -#endif - unsigned long j = jiffies; + max_load = this_load = total_load = total_pwr = 0; + busiest_load_per_task = busiest_nr_running = 0; + this_load_per_task = this_nr_running = 0; + if (idle == NOT_IDLE) + load_idx = sd->busy_idx; + else if (idle == NEWLY_IDLE) + load_idx = sd->newidle_idx; + else + load_idx = sd->idle_idx; - /* - * First do inter-node rebalancing, then intra-node rebalancing, - * if both events happen in the same tick. The inter-node - * rebalancing does not necessarily have to create a perfect - * balance within the node, since we load-balance the most loaded - * node with the current CPU. (ie. other CPUs in the local node - * are not balanced.) - */ - if (idle) { -#ifdef CONFIG_NUMA - if (!(j % IDLE_NODE_REBALANCE_TICK)) - balance_node(this_rq, idle, this_cpu); -#endif - if (!(j % IDLE_REBALANCE_TICK)) { - spin_lock(&this_rq->lock); - load_balance(this_rq, idle, cpu_to_node_mask(this_cpu)); - spin_unlock(&this_rq->lock); - } - return; - } -#ifdef CONFIG_NUMA - if (!(j % BUSY_NODE_REBALANCE_TICK)) - balance_node(this_rq, idle, this_cpu); -#endif - if (!(j % BUSY_REBALANCE_TICK)) { - spin_lock(&this_rq->lock); - load_balance(this_rq, idle, cpu_to_node_mask(this_cpu)); - spin_unlock(&this_rq->lock); - } -} -#else -/* - * on UP we do not need to balance between CPUs: - */ -static inline void rebalance_tick(runqueue_t *this_rq, int idle) -{ -} -#endif + do { + unsigned long load, group_capacity; + int local_group; + int i; + unsigned int balance_cpu = -1, first_idle_cpu = 0; + unsigned long sum_nr_running, sum_weighted_load; -DEFINE_PER_CPU(struct kernel_stat, kstat); + local_group = cpu_isset(this_cpu, group->cpumask); -EXPORT_PER_CPU_SYMBOL(kstat); + if (local_group) + balance_cpu = first_cpu(group->cpumask); -/* - * We place interactive tasks back into the active array, if possible. - * - * To guarantee that this does not starve expired tasks we ignore the - * interactivity of a task if the first expired task had to wait more - * than a 'reasonable' amount of time. This deadline timeout is - * load-dependent, as the frequency of array switched decreases with - * increasing number of running tasks. We also ignore the interactivity - * if a better static_prio task has expired: - */ -#define EXPIRED_STARVING(rq) \ - ((STARVATION_LIMIT && ((rq)->expired_timestamp && \ - (jiffies - (rq)->expired_timestamp >= \ - STARVATION_LIMIT * ((rq)->nr_running) + 1))) || \ - ((rq)->curr->static_prio > (rq)->best_expired_prio)) + /* Tally up the load of all CPUs in the group */ + sum_weighted_load = sum_nr_running = avg_load = 0; -/* - * This function gets called by the timer code, with HZ frequency. - * We call it with interrupts disabled. - * - * It also gets called by the fork code, when changing the parent's - * timeslices. - */ -void scheduler_tick(int user_ticks, int sys_ticks) -{ - int cpu = smp_processor_id(); - struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; - runqueue_t *rq = this_rq(); - task_t *p = current; + for_each_cpu_mask(i, group->cpumask) { + struct rq *rq; - rq->timestamp_last_tick = sched_clock(); + if (!cpu_isset(i, *cpus)) + continue; - if (rcu_pending(cpu)) - rcu_check_callbacks(cpu, user_ticks); + rq = cpu_rq(i); - /* note: this timer irq context must be accounted for as well */ - if (hardirq_count() - HARDIRQ_OFFSET) { - cpustat->irq += sys_ticks; - sys_ticks = 0; - } else if (softirq_count()) { - cpustat->softirq += sys_ticks; - sys_ticks = 0; - } + if (*sd_idle && !idle_cpu(i)) + *sd_idle = 0; - if (p == rq->idle) { - if (atomic_read(&rq->nr_iowait) > 0) - cpustat->iowait += sys_ticks; - else - cpustat->idle += sys_ticks; - rebalance_tick(rq, 1); - return; - } - if (TASK_NICE(p) > 0) - cpustat->nice += user_ticks; - else - cpustat->user += user_ticks; - cpustat->system += sys_ticks; + /* Bias balancing toward cpus of our domain */ + if (local_group) { + if (idle_cpu(i) && !first_idle_cpu) { + first_idle_cpu = 1; + balance_cpu = i; + } + + load = target_load(i, load_idx); + } else + load = source_load(i, load_idx); + + avg_load += load; + sum_nr_running += rq->nr_running; + sum_weighted_load += rq->raw_weighted_load; + } - /* Task might have expired already, but not scheduled off yet */ - if (p->array != rq->active) { - set_tsk_need_resched(p); - goto out; - } - spin_lock(&rq->lock); - /* - * The task was running during this tick - update the - * time slice counter. Note: we do not update a thread's - * priority until it either goes to sleep or uses up its - * timeslice. This makes it possible for interactive tasks - * to use up their timeslices at their highest priority levels. - */ - if (unlikely(rt_task(p))) { /* - * RR tasks need a special form of timeslice management. - * FIFO tasks have no timeslices. + * First idle cpu or the first cpu(busiest) in this sched group + * is eligible for doing load balancing at this and above + * domains. */ - if ((p->policy == SCHED_RR) && !--p->time_slice) { - p->time_slice = task_timeslice(p); - p->first_time_slice = 0; - set_tsk_need_resched(p); + if (local_group && balance_cpu != this_cpu && balance) { + *balance = 0; + goto ret; + } - /* put it at the end of the queue: */ - dequeue_task(p, rq->active); - enqueue_task(p, rq->active); + total_load += avg_load; + total_pwr += group->cpu_power; + + /* Adjust by relative CPU power of the group */ + avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; + + group_capacity = group->cpu_power / SCHED_LOAD_SCALE; + + if (local_group) { + this_load = avg_load; + this = group; + this_nr_running = sum_nr_running; + this_load_per_task = sum_weighted_load; + } else if (avg_load > max_load && + sum_nr_running > group_capacity) { + max_load = avg_load; + busiest = group; + busiest_nr_running = sum_nr_running; + busiest_load_per_task = sum_weighted_load; } - goto out_unlock; + +#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) + /* + * Busy processors will not participate in power savings + * balance. + */ + if (idle == NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) + goto group_next; + + /* + * If the local group is idle or completely loaded + * no need to do power savings balance at this domain + */ + if (local_group && (this_nr_running >= group_capacity || + !this_nr_running)) + power_savings_balance = 0; + + /* + * If a group is already running at full capacity or idle, + * don't include that group in power savings calculations + */ + if (!power_savings_balance || sum_nr_running >= group_capacity + || !sum_nr_running) + goto group_next; + + /* + * Calculate the group which has the least non-idle load. + * This is the group from where we need to pick up the load + * for saving power + */ + if ((sum_nr_running < min_nr_running) || + (sum_nr_running == min_nr_running && + first_cpu(group->cpumask) < + first_cpu(group_min->cpumask))) { + group_min = group; + min_nr_running = sum_nr_running; + min_load_per_task = sum_weighted_load / + sum_nr_running; + } + + /* + * Calculate the group which is almost near its + * capacity but still has some space to pick up some load + * from other group and save more power + */ + if (sum_nr_running <= group_capacity - 1) { + if (sum_nr_running > leader_nr_running || + (sum_nr_running == leader_nr_running && + first_cpu(group->cpumask) > + first_cpu(group_leader->cpumask))) { + group_leader = group; + leader_nr_running = sum_nr_running; + } + } +group_next: +#endif + group = group->next; + } while (group != sd->groups); + + if (!busiest || this_load >= max_load || busiest_nr_running == 0) + goto out_balanced; + + avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; + + if (this_load >= avg_load || + 100*max_load <= sd->imbalance_pct*this_load) + goto out_balanced; + + busiest_load_per_task /= busiest_nr_running; + /* + * We're trying to get all the cpus to the average_load, so we don't + * want to push ourselves above the average load, nor do we wish to + * reduce the max loaded cpu below the average load, as either of these + * actions would just result in more rebalancing later, and ping-pong + * tasks around. Thus we look for the minimum possible imbalance. + * Negative imbalances (*we* are more loaded than anyone else) will + * be counted as no imbalance for these purposes -- we can't fix that + * by pulling tasks to us. Be careful of negative numbers as they'll + * appear as very large values with unsigned longs. + */ + if (max_load <= busiest_load_per_task) + goto out_balanced; + + /* + * In the presence of smp nice balancing, certain scenarios can have + * max load less than avg load(as we skip the groups at or below + * its cpu_power, while calculating max_load..) + */ + if (max_load < avg_load) { + *imbalance = 0; + goto small_imbalance; } - if (!--p->time_slice) { - dequeue_task(p, rq->active); - set_tsk_need_resched(p); - p->prio = effective_prio(p); - p->time_slice = task_timeslice(p); - p->first_time_slice = 0; - if (!rq->expired_timestamp) - rq->expired_timestamp = jiffies; - if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) { - enqueue_task(p, rq->expired); - if (p->static_prio < rq->best_expired_prio) - rq->best_expired_prio = p->static_prio; + /* Don't want to pull so many tasks that a group would go idle */ + max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); + + /* How much load to actually move to equalise the imbalance */ + *imbalance = min(max_pull * busiest->cpu_power, + (avg_load - this_load) * this->cpu_power) + / SCHED_LOAD_SCALE; + + /* + * if *imbalance is less than the average load per runnable task + * there is no gaurantee that any tasks will be moved so we'll have + * a think about bumping its value to force at least one task to be + * moved + */ + if (*imbalance < busiest_load_per_task) { + unsigned long tmp, pwr_now, pwr_move; + unsigned int imbn; + +small_imbalance: + pwr_move = pwr_now = 0; + imbn = 2; + if (this_nr_running) { + this_load_per_task /= this_nr_running; + if (busiest_load_per_task > this_load_per_task) + imbn = 1; } else - enqueue_task(p, rq->active); - } else { + this_load_per_task = SCHED_LOAD_SCALE; + + if (max_load - this_load >= busiest_load_per_task * imbn) { + *imbalance = busiest_load_per_task; + return busiest; + } + /* - * Prevent a too long timeslice allowing a task to monopolize - * the CPU. We do this by splitting up the timeslice into - * smaller pieces. - * - * Note: this does not mean the task's timeslices expire or - * get lost in any way, they just might be preempted by - * another task of equal priority. (one with higher - * priority would have preempted this task already.) We - * requeue this task to the end of the list on this priority - * level, which is in essence a round-robin of tasks with - * equal priority. - * - * This only applies to tasks in the interactive - * delta range with at least TIMESLICE_GRANULARITY to requeue. + * OK, we don't have enough imbalance to justify moving tasks, + * however we may be able to increase total CPU power used by + * moving them. */ - if (TASK_INTERACTIVE(p) && !((task_timeslice(p) - - p->time_slice) % TIMESLICE_GRANULARITY(p)) && - (p->time_slice >= TIMESLICE_GRANULARITY(p)) && - (p->array == rq->active)) { - dequeue_task(p, rq->active); - set_tsk_need_resched(p); - p->prio = effective_prio(p); - enqueue_task(p, rq->active); - } + pwr_now += busiest->cpu_power * + min(busiest_load_per_task, max_load); + pwr_now += this->cpu_power * + min(this_load_per_task, this_load); + pwr_now /= SCHED_LOAD_SCALE; + + /* Amount of load we'd subtract */ + tmp = busiest_load_per_task * SCHED_LOAD_SCALE / + busiest->cpu_power; + if (max_load > tmp) + pwr_move += busiest->cpu_power * + min(busiest_load_per_task, max_load - tmp); + + /* Amount of load we'd add */ + if (max_load * busiest->cpu_power < + busiest_load_per_task * SCHED_LOAD_SCALE) + tmp = max_load * busiest->cpu_power / this->cpu_power; + else + tmp = busiest_load_per_task * SCHED_LOAD_SCALE / + this->cpu_power; + pwr_move += this->cpu_power * + min(this_load_per_task, this_load + tmp); + pwr_move /= SCHED_LOAD_SCALE; + + /* Move if we gain throughput */ + if (pwr_move <= pwr_now) + goto out_balanced; + + *imbalance = busiest_load_per_task; } -out_unlock: - spin_unlock(&rq->lock); -out: - rebalance_tick(rq, 0); + + return busiest; + +out_balanced: +#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) + if (idle == NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) + goto ret; + + if (this == group_leader && group_leader != group_min) { + *imbalance = min_load_per_task; + return group_min; + } +#endif +ret: + *imbalance = 0; + return NULL; } /* - * schedule() is the main scheduler function. + * find_busiest_queue - find the busiest runqueue among the cpus in group. */ -asmlinkage void __sched schedule(void) +static struct rq * +find_busiest_queue(struct sched_group *group, enum idle_type idle, + unsigned long imbalance, cpumask_t *cpus) { - long *switch_count; - task_t *prev, *next; - runqueue_t *rq; - prio_array_t *array; - struct list_head *queue; - unsigned long long now; - unsigned long run_time; - int idx; + struct rq *busiest = NULL, *rq; + unsigned long max_load = 0; + int i; - /* - * Test if we are atomic. Since do_exit() needs to call into - * schedule() atomically, we ignore that path for now. - * Otherwise, whine if we are scheduling when we should not be. - */ - if (likely(!(current->state & (TASK_DEAD | TASK_ZOMBIE)))) { - if (unlikely(in_atomic())) { - printk(KERN_ERR "bad: scheduling while atomic!\n"); - dump_stack(); + for_each_cpu_mask(i, group->cpumask) { + + if (!cpu_isset(i, *cpus)) + continue; + + rq = cpu_rq(i); + + if (rq->nr_running == 1 && rq->raw_weighted_load > imbalance) + continue; + + if (rq->raw_weighted_load > max_load) { + max_load = rq->raw_weighted_load; + busiest = rq; } } -need_resched: - preempt_disable(); - prev = current; - rq = this_rq(); + return busiest; +} - release_kernel_lock(prev); - now = sched_clock(); - if (likely(now - prev->timestamp < NS_MAX_SLEEP_AVG)) - run_time = now - prev->timestamp; - else - run_time = NS_MAX_SLEEP_AVG; +/* + * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but + * so long as it is large enough. + */ +#define MAX_PINNED_INTERVAL 512 - /* - * Tasks with interactive credits get charged less run_time - * at high sleep_avg to delay them losing their interactive - * status - */ - if (HIGH_CREDIT(prev)) - run_time /= (CURRENT_BONUS(prev) ? : 1); +static inline unsigned long minus_1_or_zero(unsigned long n) +{ + return n > 0 ? n - 1 : 0; +} - spin_lock_irq(&rq->lock); +/* + * Check this_cpu to ensure it is balanced within domain. Attempt to move + * tasks if there is an imbalance. + */ +static int load_balance(int this_cpu, struct rq *this_rq, + struct sched_domain *sd, enum idle_type idle, + int *balance) +{ + int nr_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; + struct sched_group *group; + unsigned long imbalance; + struct rq *busiest; + cpumask_t cpus = CPU_MASK_ALL; + unsigned long flags; /* - * if entering off of a kernel preemption go straight - * to picking the next task. + * When power savings policy is enabled for the parent domain, idle + * sibling can pick up load irrespective of busy siblings. In this case, + * let the state of idle sibling percolate up as IDLE, instead of + * portraying it as NOT_IDLE. */ - switch_count = &prev->nivcsw; - if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { - switch_count = &prev->nvcsw; - if (unlikely((prev->state & TASK_INTERRUPTIBLE) && - unlikely(signal_pending(prev)))) - prev->state = TASK_RUNNING; - else - deactivate_task(prev, rq); + if (idle != NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + sd_idle = 1; + + schedstat_inc(sd, lb_cnt[idle]); + +redo: + group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, + &cpus, balance); + + if (*balance == 0) + goto out_balanced; + + if (!group) { + schedstat_inc(sd, lb_nobusyg[idle]); + goto out_balanced; } - if (unlikely(!rq->nr_running)) { -#ifdef CONFIG_SMP - load_balance(rq, 1, cpu_to_node_mask(smp_processor_id())); -#endif - if (!rq->nr_running) { - next = rq->idle; - rq->expired_timestamp = 0; - goto switch_tasks; - } + busiest = find_busiest_queue(group, idle, imbalance, &cpus); + if (!busiest) { + schedstat_inc(sd, lb_nobusyq[idle]); + goto out_balanced; } - array = rq->active; - if (unlikely(!array->nr_active)) { + BUG_ON(busiest == this_rq); + + schedstat_add(sd, lb_imbalance[idle], imbalance); + + nr_moved = 0; + if (busiest->nr_running > 1) { /* - * Switch the active and expired arrays. + * Attempt to move tasks. If find_busiest_group has found + * an imbalance but busiest->nr_running <= 1, the group is + * still unbalanced. nr_moved simply stays zero, so it is + * correctly treated as an imbalance. */ - rq->active = rq->expired; - rq->expired = array; - array = rq->active; - rq->expired_timestamp = 0; - rq->best_expired_prio = MAX_PRIO; + local_irq_save(flags); + double_rq_lock(this_rq, busiest); + nr_moved = move_tasks(this_rq, this_cpu, busiest, + minus_1_or_zero(busiest->nr_running), + imbalance, sd, idle, &all_pinned); + double_rq_unlock(this_rq, busiest); + local_irq_restore(flags); + + /* All tasks on this runqueue were pinned by CPU affinity */ + if (unlikely(all_pinned)) { + cpu_clear(cpu_of(busiest), cpus); + if (!cpus_empty(cpus)) + goto redo; + goto out_balanced; + } } - idx = sched_find_first_bit(array->bitmap); - queue = array->queue + idx; - next = list_entry(queue->next, task_t, run_list); + if (!nr_moved) { + schedstat_inc(sd, lb_failed[idle]); + sd->nr_balance_failed++; - if (!rt_task(next) && next->activated > 0) { - unsigned long long delta = now - next->timestamp; + if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { - if (next->activated == 1) - delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128; + spin_lock_irqsave(&busiest->lock, flags); - array = next->array; - dequeue_task(next, array); - recalc_task_prio(next, next->timestamp + delta); - enqueue_task(next, array); - } - next->activated = 0; -switch_tasks: - prefetch(next); - clear_tsk_need_resched(prev); - RCU_qsctr(task_cpu(prev))++; + /* don't kick the migration_thread, if the curr + * task on busiest cpu can't be moved to this_cpu + */ + if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { + spin_unlock_irqrestore(&busiest->lock, flags); + all_pinned = 1; + goto out_one_pinned; + } - prev->sleep_avg -= run_time; - if ((long)prev->sleep_avg <= 0) { - prev->sleep_avg = 0; - if (!(HIGH_CREDIT(prev) || LOW_CREDIT(prev))) - prev->interactive_credit--; + if (!busiest->active_balance) { + busiest->active_balance = 1; + busiest->push_cpu = this_cpu; + active_balance = 1; + } + spin_unlock_irqrestore(&busiest->lock, flags); + if (active_balance) + wake_up_process(busiest->migration_thread); + + /* + * We've kicked active balancing, reset the failure + * counter. + */ + sd->nr_balance_failed = sd->cache_nice_tries+1; + } + } else + sd->nr_balance_failed = 0; + + if (likely(!active_balance)) { + /* We were unbalanced, so reset the balancing interval */ + sd->balance_interval = sd->min_interval; + } else { + /* + * If we've begun active balancing, start to back off. This + * case may not be covered by the all_pinned logic if there + * is only 1 task on the busy runqueue (because we don't call + * move_tasks). + */ + if (sd->balance_interval < sd->max_interval) + sd->balance_interval *= 2; } - prev->timestamp = now; - if (likely(prev != next)) { - next->timestamp = now; - rq->nr_switches++; - rq->curr = next; - ++*switch_count; + if (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + return -1; + return nr_moved; - prepare_arch_switch(rq, next); - prev = context_switch(rq, prev, next); - barrier(); +out_balanced: + schedstat_inc(sd, lb_balanced[idle]); - finish_task_switch(prev); - } else - spin_unlock_irq(&rq->lock); + sd->nr_balance_failed = 0; - reacquire_kernel_lock(current); - preempt_enable_no_resched(); - if (test_thread_flag(TIF_NEED_RESCHED)) - goto need_resched; -} +out_one_pinned: + /* tune up the balancing interval */ + if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || + (sd->balance_interval < sd->max_interval)) + sd->balance_interval *= 2; -EXPORT_SYMBOL(schedule); + if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + return -1; + return 0; +} -#ifdef CONFIG_PREEMPT /* - * this is is the entry point to schedule() from in-kernel preemption - * off of preempt_enable. Kernel preemptions off return from interrupt - * occur there and call schedule directly. + * Check this_cpu to ensure it is balanced within domain. Attempt to move + * tasks if there is an imbalance. + * + * Called from schedule when this_rq is about to become idle (NEWLY_IDLE). + * this_rq is locked. */ -asmlinkage void __sched preempt_schedule(void) +static int +load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) { - struct thread_info *ti = current_thread_info(); + struct sched_group *group; + struct rq *busiest = NULL; + unsigned long imbalance; + int nr_moved = 0; + int sd_idle = 0; + cpumask_t cpus = CPU_MASK_ALL; /* - * If there is a non-zero preempt_count or interrupts are disabled, - * we do not want to preempt the current task. Just return.. + * When power savings policy is enabled for the parent domain, idle + * sibling can pick up load irrespective of busy siblings. In this case, + * let the state of idle sibling percolate up as IDLE, instead of + * portraying it as NOT_IDLE. */ - if (unlikely(ti->preempt_count || irqs_disabled())) - return; + if (sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + sd_idle = 1; + + schedstat_inc(sd, lb_cnt[NEWLY_IDLE]); +redo: + group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE, + &sd_idle, &cpus, NULL); + if (!group) { + schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]); + goto out_balanced; + } -need_resched: - ti->preempt_count = PREEMPT_ACTIVE; - schedule(); - ti->preempt_count = 0; + busiest = find_busiest_queue(group, NEWLY_IDLE, imbalance, + &cpus); + if (!busiest) { + schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]); + goto out_balanced; + } - /* we could miss a preemption opportunity between schedule and now */ - barrier(); - if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) - goto need_resched; -} + BUG_ON(busiest == this_rq); -EXPORT_SYMBOL(preempt_schedule); -#endif /* CONFIG_PREEMPT */ + schedstat_add(sd, lb_imbalance[NEWLY_IDLE], imbalance); -int default_wake_function(wait_queue_t *curr, unsigned mode, int sync) -{ - task_t *p = curr->task; - return try_to_wake_up(p, mode, sync); -} + nr_moved = 0; + if (busiest->nr_running > 1) { + /* Attempt to move tasks */ + double_lock_balance(this_rq, busiest); + nr_moved = move_tasks(this_rq, this_cpu, busiest, + minus_1_or_zero(busiest->nr_running), + imbalance, sd, NEWLY_IDLE, NULL); + spin_unlock(&busiest->lock); -EXPORT_SYMBOL(default_wake_function); + if (!nr_moved) { + cpu_clear(cpu_of(busiest), cpus); + if (!cpus_empty(cpus)) + goto redo; + } + } -/* - * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just - * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve - * number) then we wake all the non-exclusive tasks and one exclusive task. - * - * There are circumstances in which we can try to wake a task which has already - * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns - * zero in this (rare) case, and we handle it by continuing to scan the queue. - */ -static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, - int nr_exclusive, int sync) -{ - struct list_head *tmp, *next; + if (!nr_moved) { + schedstat_inc(sd, lb_failed[NEWLY_IDLE]); + if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + return -1; + } else + sd->nr_balance_failed = 0; - list_for_each_safe(tmp, next, &q->task_list) { - wait_queue_t *curr; - unsigned flags; - curr = list_entry(tmp, wait_queue_t, task_list); - flags = curr->flags; - if (curr->func(curr, mode, sync) && - (flags & WQ_FLAG_EXCLUSIVE) && - !--nr_exclusive) - break; - } -} + return nr_moved; -/** - * __wake_up - wake up threads blocked on a waitqueue. - * @q: the waitqueue - * @mode: which threads - * @nr_exclusive: how many wake-one or wake-many threads to wake up - */ -void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) -{ - unsigned long flags; +out_balanced: + schedstat_inc(sd, lb_balanced[NEWLY_IDLE]); + if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && + !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) + return -1; + sd->nr_balance_failed = 0; - spin_lock_irqsave(&q->lock, flags); - __wake_up_common(q, mode, nr_exclusive, 0); - spin_unlock_irqrestore(&q->lock, flags); + return 0; } -EXPORT_SYMBOL(__wake_up); - /* - * Same as __wake_up but called with the spinlock in wait_queue_head_t held. + * idle_balance is called by schedule() if this_cpu is about to become + * idle. Attempts to pull tasks from other CPUs. */ -void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) +static void idle_balance(int this_cpu, struct rq *this_rq) { - __wake_up_common(q, mode, 1, 0); + struct sched_domain *sd; + int pulled_task = 0; + unsigned long next_balance = jiffies + 60 * HZ; + + for_each_domain(this_cpu, sd) { + if (sd->flags & SD_BALANCE_NEWIDLE) { + /* If we've pulled tasks over stop searching: */ + pulled_task = load_balance_newidle(this_cpu, + this_rq, sd); + if (time_after(next_balance, + sd->last_balance + sd->balance_interval)) + next_balance = sd->last_balance + + sd->balance_interval; + if (pulled_task) + break; + } + } + if (!pulled_task) + /* + * We are going idle. next_balance may be set based on + * a busy processor. So reset next_balance. + */ + this_rq->next_balance = next_balance; } -/** - * __wake_up - sync- wake up threads blocked on a waitqueue. - * @q: the waitqueue - * @mode: which threads - * @nr_exclusive: how many wake-one or wake-many threads to wake up - * - * The sync wakeup differs that the waker knows that it will schedule - * away soon, so while the target thread will be woken up, it will not - * be migrated to another CPU - ie. the two threads are 'synchronized' - * with each other. This can prevent needless bouncing between CPUs. +/* + * active_load_balance is run by migration threads. It pushes running tasks + * off the busiest CPU onto idle CPUs. It requires at least 1 task to be + * running on each physical CPU where possible, and avoids physical / + * logical imbalances. * - * On UP it can prevent extra preemption. + * Called with busiest_rq locked. */ -void fastcall __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) +static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) { - unsigned long flags; + int target_cpu = busiest_rq->push_cpu; + struct sched_domain *sd; + struct rq *target_rq; - if (unlikely(!q)) + /* Is there any task to move? */ + if (busiest_rq->nr_running <= 1) return; - spin_lock_irqsave(&q->lock, flags); - if (likely(nr_exclusive)) - __wake_up_common(q, mode, nr_exclusive, 1); - else - __wake_up_common(q, mode, nr_exclusive, 0); - spin_unlock_irqrestore(&q->lock, flags); -} -EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ - -void fastcall complete(struct completion *x) -{ - unsigned long flags; + target_rq = cpu_rq(target_cpu); - spin_lock_irqsave(&x->wait.lock, flags); - x->done++; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 1, 0); - spin_unlock_irqrestore(&x->wait.lock, flags); -} -EXPORT_SYMBOL(complete); + /* + * This condition is "impossible", if it occurs + * we need to fix it. Originally reported by + * Bjorn Helgaas on a 128-cpu setup. + */ + BUG_ON(busiest_rq == target_rq); -void fastcall complete_all(struct completion *x) -{ - unsigned long flags; + /* move a task from busiest_rq to target_rq */ + double_lock_balance(busiest_rq, target_rq); - spin_lock_irqsave(&x->wait.lock, flags); - x->done += UINT_MAX/2; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 0, 0); - spin_unlock_irqrestore(&x->wait.lock, flags); -} -EXPORT_SYMBOL(complete_all); + /* Search for an sd spanning us and the target CPU. */ + for_each_domain(target_cpu, sd) { + if ((sd->flags & SD_LOAD_BALANCE) && + cpu_isset(busiest_cpu, sd->span)) + break; + } -void fastcall __sched wait_for_completion(struct completion *x) -{ - might_sleep(); - spin_lock_irq(&x->wait.lock); - if (!x->done) { - DECLARE_WAITQUEUE(wait, current); + if (likely(sd)) { + schedstat_inc(sd, alb_cnt); - wait.flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_tail(&x->wait, &wait); - do { - __set_current_state(TASK_UNINTERRUPTIBLE); - spin_unlock_irq(&x->wait.lock); - schedule(); - spin_lock_irq(&x->wait.lock); - } while (!x->done); - __remove_wait_queue(&x->wait, &wait); + if (move_tasks(target_rq, target_cpu, busiest_rq, 1, + RTPRIO_TO_LOAD_WEIGHT(100), sd, SCHED_IDLE, + NULL)) + schedstat_inc(sd, alb_pushed); + else + schedstat_inc(sd, alb_failed); } - x->done--; - spin_unlock_irq(&x->wait.lock); + spin_unlock(&target_rq->lock); } -EXPORT_SYMBOL(wait_for_completion); - -#define SLEEP_ON_VAR \ - unsigned long flags; \ - wait_queue_t wait; \ - init_waitqueue_entry(&wait, current); -#define SLEEP_ON_HEAD \ - spin_lock_irqsave(&q->lock,flags); \ - __add_wait_queue(q, &wait); \ - spin_unlock(&q->lock); - -#define SLEEP_ON_TAIL \ - spin_lock_irq(&q->lock); \ - __remove_wait_queue(q, &wait); \ - spin_unlock_irqrestore(&q->lock, flags); - -void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q) +static void update_load(struct rq *this_rq) { - SLEEP_ON_VAR + unsigned long this_load; + int i, scale; - current->state = TASK_INTERRUPTIBLE; + this_load = this_rq->raw_weighted_load; - SLEEP_ON_HEAD - schedule(); - SLEEP_ON_TAIL + /* Update our load: */ + for (i = 0, scale = 1; i < 3; i++, scale <<= 1) { + unsigned long old_load, new_load; + + old_load = this_rq->cpu_load[i]; + new_load = this_load; + /* + * Round up the averaging division if load is increasing. This + * prevents us from getting stuck on 9 if the load is 10, for + * example. + */ + if (new_load > old_load) + new_load += scale-1; + this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) / scale; + } } -EXPORT_SYMBOL(interruptible_sleep_on); +/* + * run_rebalance_domains is triggered when needed from the scheduler tick. + * + * It checks each scheduling domain to see if it is due to be balanced, + * and initiates a balancing operation if so. + * + * Balancing parameters are set up in arch_init_sched_domains. + */ +static DEFINE_SPINLOCK(balancing); -long fastcall __sched interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) +static void run_rebalance_domains(struct softirq_action *h) { - SLEEP_ON_VAR - - current->state = TASK_INTERRUPTIBLE; + int this_cpu = smp_processor_id(), balance = 1; + struct rq *this_rq = cpu_rq(this_cpu); + unsigned long interval; + struct sched_domain *sd; + /* + * We are idle if there are no processes running. This + * is valid even if we are the idle process (SMT). + */ + enum idle_type idle = !this_rq->nr_running ? + SCHED_IDLE : NOT_IDLE; + /* Earliest time when we have to call run_rebalance_domains again */ + unsigned long next_balance = jiffies + 60*HZ; - SLEEP_ON_HEAD - timeout = schedule_timeout(timeout); - SLEEP_ON_TAIL + for_each_domain(this_cpu, sd) { + if (!(sd->flags & SD_LOAD_BALANCE)) + continue; - return timeout; -} + interval = sd->balance_interval; + if (idle != SCHED_IDLE) + interval *= sd->busy_factor; -EXPORT_SYMBOL(interruptible_sleep_on_timeout); + /* scale ms to jiffies */ + interval = msecs_to_jiffies(interval); + if (unlikely(!interval)) + interval = 1; -void fastcall __sched sleep_on(wait_queue_head_t *q) -{ - SLEEP_ON_VAR + if (sd->flags & SD_SERIALIZE) { + if (!spin_trylock(&balancing)) + goto out; + } - current->state = TASK_UNINTERRUPTIBLE; + if (time_after_eq(jiffies, sd->last_balance + interval)) { + if (load_balance(this_cpu, this_rq, sd, idle, &balance)) { + /* + * We've pulled tasks over so either we're no + * longer idle, or one of our SMT siblings is + * not idle. + */ + idle = NOT_IDLE; + } + sd->last_balance = jiffies; + } + if (sd->flags & SD_SERIALIZE) + spin_unlock(&balancing); +out: + if (time_after(next_balance, sd->last_balance + interval)) + next_balance = sd->last_balance + interval; - SLEEP_ON_HEAD - schedule(); - SLEEP_ON_TAIL + /* + * Stop the load balance at this level. There is another + * CPU in our sched group which is doing load balancing more + * actively. + */ + if (!balance) + break; + } + this_rq->next_balance = next_balance; } - -EXPORT_SYMBOL(sleep_on); - -long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) +#else +/* + * on UP we do not need to balance between CPUs: + */ +static inline void idle_balance(int cpu, struct rq *rq) { - SLEEP_ON_VAR - - current->state = TASK_UNINTERRUPTIBLE; - - SLEEP_ON_HEAD - timeout = schedule_timeout(timeout); - SLEEP_ON_TAIL - - return timeout; } +#endif -EXPORT_SYMBOL(sleep_on_timeout); - -void set_user_nice(task_t *p, long nice) +static inline void wake_priority_sleeper(struct rq *rq) { - unsigned long flags; - prio_array_t *array; - runqueue_t *rq; - int old_prio, new_prio, delta; - - if (TASK_NICE(p) == nice || nice < -20 || nice > 19) +#ifdef CONFIG_SCHED_SMT + if (!rq->nr_running) return; + + spin_lock(&rq->lock); /* - * We have to be careful, if called from sys_setpriority(), - * the task might be in the middle of scheduling on another CPU. - */ - rq = task_rq_lock(p, &flags); - /* - * The RT priorities are set via setscheduler(), but we still - * allow the 'normal' nice value to be set - but as expected - * it wont have any effect on scheduling until the task is - * not SCHED_NORMAL: + * If an SMT sibling task has been put to sleep for priority + * reasons reschedule the idle task to see if it can now run. */ - if (rt_task(p)) { - p->static_prio = NICE_TO_PRIO(nice); - goto out_unlock; - } - array = p->array; - if (array) - dequeue_task(p, array); - - old_prio = p->prio; - new_prio = NICE_TO_PRIO(nice); - delta = new_prio - old_prio; - p->static_prio = NICE_TO_PRIO(nice); - p->prio += delta; - - if (array) { - enqueue_task(p, array); - /* - * If the task increased its priority or is running and - * lowered its priority, then reschedule its CPU: - */ - if (delta < 0 || (delta > 0 && task_running(rq, p))) - resched_task(rq->curr); - } -out_unlock: - task_rq_unlock(rq, &flags); + if (rq->nr_running) + resched_task(rq->idle); + spin_unlock(&rq->lock); +#endif } -EXPORT_SYMBOL(set_user_nice); +DEFINE_PER_CPU(struct kernel_stat, kstat); -#ifndef __alpha__ +EXPORT_PER_CPU_SYMBOL(kstat); /* - * sys_nice - change the priority of the current process. - * @increment: priority increment - * - * sys_setpriority is a more generic, but much slower function that - * does similar things. + * This is called on clock ticks and on context switches. + * Bank in p->sched_time the ns elapsed since the last tick or switch. */ -asmlinkage long sys_nice(int increment) +static inline void +update_cpu_clock(struct task_struct *p, struct rq *rq, unsigned long long now) { - int retval; - long nice; - - /* - * Setpriority might change our priority at the same moment. - * We don't have to worry. Conceptually one call occurs first - * and we have a single winner. - */ - if (increment < 0) { - if (!capable(CAP_SYS_NICE)) - return -EPERM; - if (increment < -40) - increment = -40; - } - if (increment > 40) - increment = 40; + p->sched_time += now - p->last_ran; + p->last_ran = rq->most_recent_timestamp = now; +} - nice = PRIO_TO_NICE(current->static_prio) + increment; - if (nice < -20) - nice = -20; - if (nice > 19) - nice = 19; +/* + * Return current->sched_time plus any more ns on the sched_clock + * that have not yet been banked. + */ +unsigned long long current_sched_time(const struct task_struct *p) +{ + unsigned long long ns; + unsigned long flags; - retval = security_task_setnice(current, nice); - if (retval) - return retval; + local_irq_save(flags); + ns = p->sched_time + sched_clock() - p->last_ran; + local_irq_restore(flags); - set_user_nice(current, nice); - return 0; + return ns; } -#endif - -/** - * task_prio - return the priority value of a given task. - * @p: the task in question. +/* + * We place interactive tasks back into the active array, if possible. * - * This is the priority value as seen by users in /proc. - * RT tasks are offset by -200. Normal tasks are centered - * around 0, value goes from -16 to +15. + * To guarantee that this does not starve expired tasks we ignore the + * interactivity of a task if the first expired task had to wait more + * than a 'reasonable' amount of time. This deadline timeout is + * load-dependent, as the frequency of array switched decreases with + * increasing number of running tasks. We also ignore the interactivity + * if a better static_prio task has expired: */ -int task_prio(task_t *p) +static inline int expired_starving(struct rq *rq) { - return p->prio - MAX_RT_PRIO; + if (rq->curr->static_prio > rq->best_expired_prio) + return 1; + if (!STARVATION_LIMIT || !rq->expired_timestamp) + return 0; + if (jiffies - rq->expired_timestamp > STARVATION_LIMIT * rq->nr_running) + return 1; + return 0; } -/** - * task_nice - return the nice value of a given task. - * @p: the task in question. +/* + * Account user cpu time to a process. + * @p: the process that the cpu time gets accounted to + * @hardirq_offset: the offset to subtract from hardirq_count() + * @cputime: the cpu time spent in user space since the last update */ -int task_nice(task_t *p) +void account_user_time(struct task_struct *p, cputime_t cputime) { - return TASK_NICE(p); -} + struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; + struct vx_info *vxi = p->vx_info; /* p is _always_ current */ + cputime64_t tmp; + int nice = (TASK_NICE(p) > 0); -EXPORT_SYMBOL(task_nice); + p->utime = cputime_add(p->utime, cputime); + vx_account_user(vxi, cputime, nice); -/** - * idle_cpu - is a given cpu idle currently? - * @cpu: the processor in question. - */ -int idle_cpu(int cpu) -{ - return cpu_curr(cpu) == cpu_rq(cpu)->idle; + /* Add user time to cpustat. */ + tmp = cputime_to_cputime64(cputime); + if (nice) + cpustat->nice = cputime64_add(cpustat->nice, tmp); + else + cpustat->user = cputime64_add(cpustat->user, tmp); } -EXPORT_SYMBOL_GPL(idle_cpu); - -/** - * find_process_by_pid - find a process with a matching PID value. - * @pid: the pid in question. +/* + * Account system cpu time to a process. + * @p: the process that the cpu time gets accounted to + * @hardirq_offset: the offset to subtract from hardirq_count() + * @cputime: the cpu time spent in kernel space since the last update */ -static inline task_t *find_process_by_pid(pid_t pid) +void account_system_time(struct task_struct *p, int hardirq_offset, + cputime_t cputime) { - return pid ? find_task_by_pid(pid) : current; -} - -/* Actually do priority change: must hold rq lock. */ -static void __setscheduler(struct task_struct *p, int policy, int prio) -{ - BUG_ON(p->array); - p->policy = policy; - p->rt_priority = prio; - if (policy != SCHED_NORMAL) - p->prio = MAX_USER_RT_PRIO-1 - p->rt_priority; + struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; + struct vx_info *vxi = p->vx_info; /* p is _always_ current */ + struct rq *rq = this_rq(); + cputime64_t tmp; + + p->stime = cputime_add(p->stime, cputime); + vx_account_system(vxi, cputime, (p == rq->idle)); + + /* Add system time to cpustat. */ + tmp = cputime_to_cputime64(cputime); + if (hardirq_count() - hardirq_offset) + cpustat->irq = cputime64_add(cpustat->irq, tmp); + else if (softirq_count()) + cpustat->softirq = cputime64_add(cpustat->softirq, tmp); + else if (p != rq->idle) + cpustat->system = cputime64_add(cpustat->system, tmp); + else if (atomic_read(&rq->nr_iowait) > 0) + cpustat->iowait = cputime64_add(cpustat->iowait, tmp); else - p->prio = p->static_prio; + cpustat->idle = cputime64_add(cpustat->idle, tmp); + /* Account for system time used */ + acct_update_integrals(p); } /* - * setscheduler - change the scheduling policy and/or RT priority of a thread. + * Account for involuntary wait time. + * @p: the process from which the cpu time has been stolen + * @steal: the cpu time spent in involuntary wait */ -static int setscheduler(pid_t pid, int policy, struct sched_param __user *param) +void account_steal_time(struct task_struct *p, cputime_t steal) { - struct sched_param lp; - int retval = -EINVAL; - int oldprio; - prio_array_t *array; - unsigned long flags; - runqueue_t *rq; - task_t *p; - - if (!param || pid < 0) - goto out_nounlock; + struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; + cputime64_t tmp = cputime_to_cputime64(steal); + struct rq *rq = this_rq(); - retval = -EFAULT; - if (copy_from_user(&lp, param, sizeof(struct sched_param))) - goto out_nounlock; + if (p == rq->idle) { + p->stime = cputime_add(p->stime, steal); + if (atomic_read(&rq->nr_iowait) > 0) + cpustat->iowait = cputime64_add(cpustat->iowait, tmp); + else + cpustat->idle = cputime64_add(cpustat->idle, tmp); + } else + cpustat->steal = cputime64_add(cpustat->steal, tmp); +} + +static void task_running_tick(struct rq *rq, struct task_struct *p, int cpu) +{ + if (p->array != rq->active) { + /* Task has expired but was not scheduled yet */ + set_tsk_need_resched(p); + return; + } + spin_lock(&rq->lock); + /* + * The task was running during this tick - update the + * time slice counter. Note: we do not update a thread's + * priority until it either goes to sleep or uses up its + * timeslice. This makes it possible for interactive tasks + * to use up their timeslices at their highest priority levels. + */ + if (rt_task(p)) { + /* + * RR tasks need a special form of timeslice management. + * FIFO tasks have no timeslices. + */ + if ((p->policy == SCHED_RR) && !--p->time_slice) { + p->time_slice = task_timeslice(p); + p->first_time_slice = 0; + set_tsk_need_resched(p); + + /* put it at the end of the queue: */ + requeue_task(p, rq->active); + } + goto out_unlock; + } + if (vx_need_resched(p, --p->time_slice, cpu)) { + dequeue_task(p, rq->active); + set_tsk_need_resched(p); + p->prio = effective_prio(p); + p->time_slice = task_timeslice(p); + p->first_time_slice = 0; + + if (!rq->expired_timestamp) + rq->expired_timestamp = jiffies; + if (!TASK_INTERACTIVE(p) || expired_starving(rq)) { + enqueue_task(p, rq->expired); + if (p->static_prio < rq->best_expired_prio) + rq->best_expired_prio = p->static_prio; + } else + enqueue_task(p, rq->active); + } else { + /* + * Prevent a too long timeslice allowing a task to monopolize + * the CPU. We do this by splitting up the timeslice into + * smaller pieces. + * + * Note: this does not mean the task's timeslices expire or + * get lost in any way, they just might be preempted by + * another task of equal priority. (one with higher + * priority would have preempted this task already.) We + * requeue this task to the end of the list on this priority + * level, which is in essence a round-robin of tasks with + * equal priority. + * + * This only applies to tasks in the interactive + * delta range with at least TIMESLICE_GRANULARITY to requeue. + */ + if (TASK_INTERACTIVE(p) && !((task_timeslice(p) - + p->time_slice) % TIMESLICE_GRANULARITY(p)) && + (p->time_slice >= TIMESLICE_GRANULARITY(p)) && + (p->array == rq->active)) { + + requeue_task(p, rq->active); + set_tsk_need_resched(p); + } + } +out_unlock: + spin_unlock(&rq->lock); +} + +/* + * This function gets called by the timer code, with HZ frequency. + * We call it with interrupts disabled. + * + * It also gets called by the fork code, when changing the parent's + * timeslices. + */ +void scheduler_tick(void) +{ + unsigned long long now = sched_clock(); + struct task_struct *p = current; + int cpu = smp_processor_id(); + struct rq *rq = cpu_rq(cpu); + + update_cpu_clock(p, rq, now); + vxm_sync(now, cpu); + + if (p == rq->idle) { + /* Task on the idle queue */ + wake_priority_sleeper(rq); + vx_idle_resched(rq); + } else + task_running_tick(rq, p, cpu); +#ifdef CONFIG_SMP + update_load(rq); + if (time_after_eq(jiffies, rq->next_balance)) + raise_softirq(SCHED_SOFTIRQ); +#endif +} + +#ifdef CONFIG_SCHED_SMT +static inline void wakeup_busy_runqueue(struct rq *rq) +{ + /* If an SMT runqueue is sleeping due to priority reasons wake it up */ + if (rq->curr == rq->idle && rq->nr_running) + resched_task(rq->idle); +} + +/* + * Called with interrupt disabled and this_rq's runqueue locked. + */ +static void wake_sleeping_dependent(int this_cpu) +{ + struct sched_domain *tmp, *sd = NULL; + int i; + + for_each_domain(this_cpu, tmp) { + if (tmp->flags & SD_SHARE_CPUPOWER) { + sd = tmp; + break; + } + } + + if (!sd) + return; + + for_each_cpu_mask(i, sd->span) { + struct rq *smt_rq = cpu_rq(i); + + if (i == this_cpu) + continue; + if (unlikely(!spin_trylock(&smt_rq->lock))) + continue; + + wakeup_busy_runqueue(smt_rq); + spin_unlock(&smt_rq->lock); + } +} + +/* + * number of 'lost' timeslices this task wont be able to fully + * utilize, if another task runs on a sibling. This models the + * slowdown effect of other tasks running on siblings: + */ +static inline unsigned long +smt_slice(struct task_struct *p, struct sched_domain *sd) +{ + return p->time_slice * (100 - sd->per_cpu_gain) / 100; +} + +/* + * To minimise lock contention and not have to drop this_rq's runlock we only + * trylock the sibling runqueues and bypass those runqueues if we fail to + * acquire their lock. As we only trylock the normal locking order does not + * need to be obeyed. + */ +static int +dependent_sleeper(int this_cpu, struct rq *this_rq, struct task_struct *p) +{ + struct sched_domain *tmp, *sd = NULL; + int ret = 0, i; + + /* kernel/rt threads do not participate in dependent sleeping */ + if (!p->mm || rt_task(p)) + return 0; + + for_each_domain(this_cpu, tmp) { + if (tmp->flags & SD_SHARE_CPUPOWER) { + sd = tmp; + break; + } + } + + if (!sd) + return 0; + + for_each_cpu_mask(i, sd->span) { + struct task_struct *smt_curr; + struct rq *smt_rq; + + if (i == this_cpu) + continue; + + smt_rq = cpu_rq(i); + if (unlikely(!spin_trylock(&smt_rq->lock))) + continue; + + smt_curr = smt_rq->curr; + + if (!smt_curr->mm) + goto unlock; + + /* + * If a user task with lower static priority than the + * running task on the SMT sibling is trying to schedule, + * delay it till there is proportionately less timeslice + * left of the sibling task to prevent a lower priority + * task from using an unfair proportion of the + * physical cpu's resources. -ck + */ + if (rt_task(smt_curr)) { + /* + * With real time tasks we run non-rt tasks only + * per_cpu_gain% of the time. + */ + if ((jiffies % DEF_TIMESLICE) > + (sd->per_cpu_gain * DEF_TIMESLICE / 100)) + ret = 1; + } else { + if (smt_curr->static_prio < p->static_prio && + !TASK_PREEMPTS_CURR(p, smt_rq) && + smt_slice(smt_curr, sd) > task_timeslice(p)) + ret = 1; + } +unlock: + spin_unlock(&smt_rq->lock); + } + return ret; +} +#else +static inline void wake_sleeping_dependent(int this_cpu) +{ +} +static inline int +dependent_sleeper(int this_cpu, struct rq *this_rq, struct task_struct *p) +{ + return 0; +} +#endif + +#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) + +void fastcall add_preempt_count(int val) +{ + /* + * Underflow? + */ + if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) + return; + preempt_count() += val; + /* + * Spinlock count overflowing soon? + */ + DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= + PREEMPT_MASK - 10); +} +EXPORT_SYMBOL(add_preempt_count); + +void fastcall sub_preempt_count(int val) +{ + /* + * Underflow? + */ + if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) + return; + /* + * Is the spinlock portion underflowing? + */ + if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && + !(preempt_count() & PREEMPT_MASK))) + return; + + preempt_count() -= val; +} +EXPORT_SYMBOL(sub_preempt_count); + +#endif + +static inline int interactive_sleep(enum sleep_type sleep_type) +{ + return (sleep_type == SLEEP_INTERACTIVE || + sleep_type == SLEEP_INTERRUPTED); +} + +/* + * schedule() is the main scheduler function. + */ +asmlinkage void __sched schedule(void) +{ + struct task_struct *prev, *next; + struct prio_array *array; + struct list_head *queue; + unsigned long long now; + unsigned long run_time; + int cpu, idx, new_prio; + long *switch_count; + struct rq *rq; + + /* + * Test if we are atomic. Since do_exit() needs to call into + * schedule() atomically, we ignore that path for now. + * Otherwise, whine if we are scheduling when we should not be. + */ + if (unlikely(in_atomic() && !current->exit_state)) { + printk(KERN_ERR "BUG: scheduling while atomic: " + "%s/0x%08x/%d\n", + current->comm, preempt_count(), current->pid); + debug_show_held_locks(current); + if (irqs_disabled()) + print_irqtrace_events(current); + dump_stack(); + } + profile_hit(SCHED_PROFILING, __builtin_return_address(0)); + +need_resched: + preempt_disable(); + prev = current; + release_kernel_lock(prev); +need_resched_nonpreemptible: + rq = this_rq(); + + /* + * The idle thread is not allowed to schedule! + * Remove this check after it has been exercised a bit. + */ + if (unlikely(prev == rq->idle) && prev->state != TASK_RUNNING) { + printk(KERN_ERR "bad: scheduling from the idle thread!\n"); + dump_stack(); + } + + schedstat_inc(rq, sched_cnt); + now = sched_clock(); + if (likely((long long)(now - prev->timestamp) < NS_MAX_SLEEP_AVG)) { + run_time = now - prev->timestamp; + if (unlikely((long long)(now - prev->timestamp) < 0)) + run_time = 0; + } else + run_time = NS_MAX_SLEEP_AVG; + + /* + * Tasks charged proportionately less run_time at high sleep_avg to + * delay them losing their interactive status + */ + run_time /= (CURRENT_BONUS(prev) ? : 1); + + spin_lock_irq(&rq->lock); + + switch_count = &prev->nivcsw; + if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { + switch_count = &prev->nvcsw; + if (unlikely((prev->state & TASK_INTERRUPTIBLE) && + unlikely(signal_pending(prev)))) + prev->state = TASK_RUNNING; + else { + if (prev->state == TASK_UNINTERRUPTIBLE) { + rq->nr_uninterruptible++; + vx_uninterruptible_inc(prev); + } + deactivate_task(prev, rq); + } + } + + cpu = smp_processor_id(); + vx_set_rq_time(rq, jiffies); +try_unhold: + vx_try_unhold(rq, cpu); +pick_next: + + if (unlikely(!rq->nr_running)) { + /* can we skip idle time? */ + if (vx_try_skip(rq, cpu)) + goto try_unhold; + + idle_balance(cpu, rq); + if (!rq->nr_running) { + next = rq->idle; + rq->expired_timestamp = 0; + wake_sleeping_dependent(cpu); + goto switch_tasks; + } + } + + array = rq->active; + if (unlikely(!array->nr_active)) { + /* + * Switch the active and expired arrays. + */ + schedstat_inc(rq, sched_switch); + rq->active = rq->expired; + rq->expired = array; + array = rq->active; + rq->expired_timestamp = 0; + rq->best_expired_prio = MAX_PRIO; + } + + idx = sched_find_first_bit(array->bitmap); + queue = array->queue + idx; + next = list_entry(queue->next, struct task_struct, run_list); + + /* check before we schedule this context */ + if (!vx_schedule(next, rq, cpu)) + goto pick_next; + + if (!rt_task(next) && interactive_sleep(next->sleep_type)) { + unsigned long long delta = now - next->timestamp; + if (unlikely((long long)(now - next->timestamp) < 0)) + delta = 0; + + if (next->sleep_type == SLEEP_INTERACTIVE) + delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128; + + array = next->array; + new_prio = recalc_task_prio(next, next->timestamp + delta); + + if (unlikely(next->prio != new_prio)) { + dequeue_task(next, array); + next->prio = new_prio; + enqueue_task(next, array); + } + } + next->sleep_type = SLEEP_NORMAL; + if (rq->nr_running == 1 && dependent_sleeper(cpu, rq, next)) + next = rq->idle; +switch_tasks: + if (next == rq->idle) + schedstat_inc(rq, sched_goidle); + prefetch(next); + prefetch_stack(next); + clear_tsk_need_resched(prev); + rcu_qsctr_inc(task_cpu(prev)); + + update_cpu_clock(prev, rq, now); + + prev->sleep_avg -= run_time; + if ((long)prev->sleep_avg <= 0) + prev->sleep_avg = 0; + prev->timestamp = prev->last_ran = now; + + sched_info_switch(prev, next); + if (likely(prev != next)) { + next->timestamp = next->last_ran = now; + rq->nr_switches++; + rq->curr = next; + ++*switch_count; + + prepare_task_switch(rq, next); + prev = context_switch(rq, prev, next); + barrier(); + /* + * this_rq must be evaluated again because prev may have moved + * CPUs since it called schedule(), thus the 'rq' on its stack + * frame will be invalid. + */ + finish_task_switch(this_rq(), prev); + } else + spin_unlock_irq(&rq->lock); + + prev = current; + if (unlikely(reacquire_kernel_lock(prev) < 0)) + goto need_resched_nonpreemptible; + preempt_enable_no_resched(); + if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) + goto need_resched; +} +EXPORT_SYMBOL(schedule); + +#ifdef CONFIG_PREEMPT +/* + * this is the entry point to schedule() from in-kernel preemption + * off of preempt_enable. Kernel preemptions off return from interrupt + * occur there and call schedule directly. + */ +asmlinkage void __sched preempt_schedule(void) +{ + struct thread_info *ti = current_thread_info(); +#ifdef CONFIG_PREEMPT_BKL + struct task_struct *task = current; + int saved_lock_depth; +#endif + /* + * If there is a non-zero preempt_count or interrupts are disabled, + * we do not want to preempt the current task. Just return.. + */ + if (likely(ti->preempt_count || irqs_disabled())) + return; + +need_resched: + add_preempt_count(PREEMPT_ACTIVE); + /* + * We keep the big kernel semaphore locked, but we + * clear ->lock_depth so that schedule() doesnt + * auto-release the semaphore: + */ +#ifdef CONFIG_PREEMPT_BKL + saved_lock_depth = task->lock_depth; + task->lock_depth = -1; +#endif + schedule(); +#ifdef CONFIG_PREEMPT_BKL + task->lock_depth = saved_lock_depth; +#endif + sub_preempt_count(PREEMPT_ACTIVE); + + /* we could miss a preemption opportunity between schedule and now */ + barrier(); + if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) + goto need_resched; +} +EXPORT_SYMBOL(preempt_schedule); + +/* + * this is the entry point to schedule() from kernel preemption + * off of irq context. + * Note, that this is called and return with irqs disabled. This will + * protect us against recursive calling from irq. + */ +asmlinkage void __sched preempt_schedule_irq(void) +{ + struct thread_info *ti = current_thread_info(); +#ifdef CONFIG_PREEMPT_BKL + struct task_struct *task = current; + int saved_lock_depth; +#endif + /* Catch callers which need to be fixed */ + BUG_ON(ti->preempt_count || !irqs_disabled()); + +need_resched: + add_preempt_count(PREEMPT_ACTIVE); + /* + * We keep the big kernel semaphore locked, but we + * clear ->lock_depth so that schedule() doesnt + * auto-release the semaphore: + */ +#ifdef CONFIG_PREEMPT_BKL + saved_lock_depth = task->lock_depth; + task->lock_depth = -1; +#endif + local_irq_enable(); + schedule(); + local_irq_disable(); +#ifdef CONFIG_PREEMPT_BKL + task->lock_depth = saved_lock_depth; +#endif + sub_preempt_count(PREEMPT_ACTIVE); + + /* we could miss a preemption opportunity between schedule and now */ + barrier(); + if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) + goto need_resched; +} + +#endif /* CONFIG_PREEMPT */ + +int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, + void *key) +{ + return try_to_wake_up(curr->private, mode, sync); +} +EXPORT_SYMBOL(default_wake_function); + +/* + * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just + * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve + * number) then we wake all the non-exclusive tasks and one exclusive task. + * + * There are circumstances in which we can try to wake a task which has already + * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns + * zero in this (rare) case, and we handle it by continuing to scan the queue. + */ +static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, + int nr_exclusive, int sync, void *key) +{ + struct list_head *tmp, *next; + + list_for_each_safe(tmp, next, &q->task_list) { + wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list); + unsigned flags = curr->flags; + + if (curr->func(curr, mode, sync, key) && + (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) + break; + } +} + +/** + * __wake_up - wake up threads blocked on a waitqueue. + * @q: the waitqueue + * @mode: which threads + * @nr_exclusive: how many wake-one or wake-many threads to wake up + * @key: is directly passed to the wakeup function + */ +void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, + int nr_exclusive, void *key) +{ + unsigned long flags; + + spin_lock_irqsave(&q->lock, flags); + __wake_up_common(q, mode, nr_exclusive, 0, key); + spin_unlock_irqrestore(&q->lock, flags); +} +EXPORT_SYMBOL(__wake_up); + +/* + * Same as __wake_up but called with the spinlock in wait_queue_head_t held. + */ +void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) +{ + __wake_up_common(q, mode, 1, 0, NULL); +} + +/** + * __wake_up_sync - wake up threads blocked on a waitqueue. + * @q: the waitqueue + * @mode: which threads + * @nr_exclusive: how many wake-one or wake-many threads to wake up + * + * The sync wakeup differs that the waker knows that it will schedule + * away soon, so while the target thread will be woken up, it will not + * be migrated to another CPU - ie. the two threads are 'synchronized' + * with each other. This can prevent needless bouncing between CPUs. + * + * On UP it can prevent extra preemption. + */ +void fastcall +__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) +{ + unsigned long flags; + int sync = 1; + + if (unlikely(!q)) + return; + + if (unlikely(!nr_exclusive)) + sync = 0; + + spin_lock_irqsave(&q->lock, flags); + __wake_up_common(q, mode, nr_exclusive, sync, NULL); + spin_unlock_irqrestore(&q->lock, flags); +} +EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ + +void fastcall complete(struct completion *x) +{ + unsigned long flags; + + spin_lock_irqsave(&x->wait.lock, flags); + x->done++; + __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, + 1, 0, NULL); + spin_unlock_irqrestore(&x->wait.lock, flags); +} +EXPORT_SYMBOL(complete); + +void fastcall complete_all(struct completion *x) +{ + unsigned long flags; + + spin_lock_irqsave(&x->wait.lock, flags); + x->done += UINT_MAX/2; + __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, + 0, 0, NULL); + spin_unlock_irqrestore(&x->wait.lock, flags); +} +EXPORT_SYMBOL(complete_all); + +void fastcall __sched wait_for_completion(struct completion *x) +{ + might_sleep(); + + spin_lock_irq(&x->wait.lock); + if (!x->done) { + DECLARE_WAITQUEUE(wait, current); + + wait.flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue_tail(&x->wait, &wait); + do { + __set_current_state(TASK_UNINTERRUPTIBLE); + spin_unlock_irq(&x->wait.lock); + schedule(); + spin_lock_irq(&x->wait.lock); + } while (!x->done); + __remove_wait_queue(&x->wait, &wait); + } + x->done--; + spin_unlock_irq(&x->wait.lock); +} +EXPORT_SYMBOL(wait_for_completion); + +unsigned long fastcall __sched +wait_for_completion_timeout(struct completion *x, unsigned long timeout) +{ + might_sleep(); + + spin_lock_irq(&x->wait.lock); + if (!x->done) { + DECLARE_WAITQUEUE(wait, current); + + wait.flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue_tail(&x->wait, &wait); + do { + __set_current_state(TASK_UNINTERRUPTIBLE); + spin_unlock_irq(&x->wait.lock); + timeout = schedule_timeout(timeout); + spin_lock_irq(&x->wait.lock); + if (!timeout) { + __remove_wait_queue(&x->wait, &wait); + goto out; + } + } while (!x->done); + __remove_wait_queue(&x->wait, &wait); + } + x->done--; +out: + spin_unlock_irq(&x->wait.lock); + return timeout; +} +EXPORT_SYMBOL(wait_for_completion_timeout); + +int fastcall __sched wait_for_completion_interruptible(struct completion *x) +{ + int ret = 0; + + might_sleep(); + + spin_lock_irq(&x->wait.lock); + if (!x->done) { + DECLARE_WAITQUEUE(wait, current); + + wait.flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue_tail(&x->wait, &wait); + do { + if (signal_pending(current)) { + ret = -ERESTARTSYS; + __remove_wait_queue(&x->wait, &wait); + goto out; + } + __set_current_state(TASK_INTERRUPTIBLE); + spin_unlock_irq(&x->wait.lock); + schedule(); + spin_lock_irq(&x->wait.lock); + } while (!x->done); + __remove_wait_queue(&x->wait, &wait); + } + x->done--; +out: + spin_unlock_irq(&x->wait.lock); + + return ret; +} +EXPORT_SYMBOL(wait_for_completion_interruptible); + +unsigned long fastcall __sched +wait_for_completion_interruptible_timeout(struct completion *x, + unsigned long timeout) +{ + might_sleep(); + + spin_lock_irq(&x->wait.lock); + if (!x->done) { + DECLARE_WAITQUEUE(wait, current); + + wait.flags |= WQ_FLAG_EXCLUSIVE; + __add_wait_queue_tail(&x->wait, &wait); + do { + if (signal_pending(current)) { + timeout = -ERESTARTSYS; + __remove_wait_queue(&x->wait, &wait); + goto out; + } + __set_current_state(TASK_INTERRUPTIBLE); + spin_unlock_irq(&x->wait.lock); + timeout = schedule_timeout(timeout); + spin_lock_irq(&x->wait.lock); + if (!timeout) { + __remove_wait_queue(&x->wait, &wait); + goto out; + } + } while (!x->done); + __remove_wait_queue(&x->wait, &wait); + } + x->done--; +out: + spin_unlock_irq(&x->wait.lock); + return timeout; +} +EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); + + +#define SLEEP_ON_VAR \ + unsigned long flags; \ + wait_queue_t wait; \ + init_waitqueue_entry(&wait, current); + +#define SLEEP_ON_HEAD \ + spin_lock_irqsave(&q->lock,flags); \ + __add_wait_queue(q, &wait); \ + spin_unlock(&q->lock); + +#define SLEEP_ON_TAIL \ + spin_lock_irq(&q->lock); \ + __remove_wait_queue(q, &wait); \ + spin_unlock_irqrestore(&q->lock, flags); + +#define SLEEP_ON_BKLCHECK \ + if (unlikely(!kernel_locked()) && \ + sleep_on_bkl_warnings < 10) { \ + sleep_on_bkl_warnings++; \ + WARN_ON(1); \ + } + +static int sleep_on_bkl_warnings; + +void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q) +{ + SLEEP_ON_VAR + + SLEEP_ON_BKLCHECK + + current->state = TASK_INTERRUPTIBLE; + + SLEEP_ON_HEAD + schedule(); + SLEEP_ON_TAIL +} +EXPORT_SYMBOL(interruptible_sleep_on); + +long fastcall __sched +interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) +{ + SLEEP_ON_VAR + + SLEEP_ON_BKLCHECK + + current->state = TASK_INTERRUPTIBLE; + + SLEEP_ON_HEAD + timeout = schedule_timeout(timeout); + SLEEP_ON_TAIL + + return timeout; +} +EXPORT_SYMBOL(interruptible_sleep_on_timeout); + +long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) +{ + SLEEP_ON_VAR + + SLEEP_ON_BKLCHECK + + current->state = TASK_UNINTERRUPTIBLE; + + SLEEP_ON_HEAD + timeout = schedule_timeout(timeout); + SLEEP_ON_TAIL + + return timeout; +} + +EXPORT_SYMBOL(sleep_on_timeout); + +#ifdef CONFIG_RT_MUTEXES + +/* + * rt_mutex_setprio - set the current priority of a task + * @p: task + * @prio: prio value (kernel-internal form) + * + * This function changes the 'effective' priority of a task. It does + * not touch ->normal_prio like __setscheduler(). + * + * Used by the rt_mutex code to implement priority inheritance logic. + */ +void rt_mutex_setprio(struct task_struct *p, int prio) +{ + struct prio_array *array; + unsigned long flags; + struct rq *rq; + int oldprio; + + BUG_ON(prio < 0 || prio > MAX_PRIO); + + rq = task_rq_lock(p, &flags); + + oldprio = p->prio; + array = p->array; + if (array) + dequeue_task(p, array); + p->prio = prio; + + if (array) { + /* + * If changing to an RT priority then queue it + * in the active array! + */ + if (rt_task(p)) + array = rq->active; + enqueue_task(p, array); + /* + * Reschedule if we are currently running on this runqueue and + * our priority decreased, or if we are not currently running on + * this runqueue and our priority is higher than the current's + */ + if (task_running(rq, p)) { + if (p->prio > oldprio) + resched_task(rq->curr); + } else if (TASK_PREEMPTS_CURR(p, rq)) + resched_task(rq->curr); + } + task_rq_unlock(rq, &flags); +} + +#endif + +void set_user_nice(struct task_struct *p, long nice) +{ + struct prio_array *array; + int old_prio, delta; + unsigned long flags; + struct rq *rq; + + if (TASK_NICE(p) == nice || nice < -20 || nice > 19) + return; + /* + * We have to be careful, if called from sys_setpriority(), + * the task might be in the middle of scheduling on another CPU. + */ + rq = task_rq_lock(p, &flags); + /* + * The RT priorities are set via sched_setscheduler(), but we still + * allow the 'normal' nice value to be set - but as expected + * it wont have any effect on scheduling until the task is + * not SCHED_NORMAL/SCHED_BATCH: + */ + if (has_rt_policy(p)) { + p->static_prio = NICE_TO_PRIO(nice); + goto out_unlock; + } + array = p->array; + if (array) { + dequeue_task(p, array); + dec_raw_weighted_load(rq, p); + } + + p->static_prio = NICE_TO_PRIO(nice); + set_load_weight(p); + old_prio = p->prio; + p->prio = effective_prio(p); + delta = p->prio - old_prio; + + if (array) { + enqueue_task(p, array); + inc_raw_weighted_load(rq, p); + /* + * If the task increased its priority or is running and + * lowered its priority, then reschedule its CPU: + */ + if (delta < 0 || (delta > 0 && task_running(rq, p))) + resched_task(rq->curr); + } +out_unlock: + task_rq_unlock(rq, &flags); +} +EXPORT_SYMBOL(set_user_nice); + +/* + * can_nice - check if a task can reduce its nice value + * @p: task + * @nice: nice value + */ +int can_nice(const struct task_struct *p, const int nice) +{ + /* convert nice value [19,-20] to rlimit style value [1,40] */ + int nice_rlim = 20 - nice; + + return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || + capable(CAP_SYS_NICE)); +} + +#ifdef __ARCH_WANT_SYS_NICE + +/* + * sys_nice - change the priority of the current process. + * @increment: priority increment + * + * sys_setpriority is a more generic, but much slower function that + * does similar things. + */ +asmlinkage long sys_nice(int increment) +{ + long nice, retval; + + /* + * Setpriority might change our priority at the same moment. + * We don't have to worry. Conceptually one call occurs first + * and we have a single winner. + */ + if (increment < -40) + increment = -40; + if (increment > 40) + increment = 40; + + nice = PRIO_TO_NICE(current->static_prio) + increment; + if (nice < -20) + nice = -20; + if (nice > 19) + nice = 19; + + if (increment < 0 && !can_nice(current, nice)) + return vx_flags(VXF_IGNEG_NICE, 0) ? 0 : -EPERM; + + retval = security_task_setnice(current, nice); + if (retval) + return retval; + + set_user_nice(current, nice); + return 0; +} + +#endif + +/** + * task_prio - return the priority value of a given task. + * @p: the task in question. + * + * This is the priority value as seen by users in /proc. + * RT tasks are offset by -200. Normal tasks are centered + * around 0, value goes from -16 to +15. + */ +int task_prio(const struct task_struct *p) +{ + return p->prio - MAX_RT_PRIO; +} + +/** + * task_nice - return the nice value of a given task. + * @p: the task in question. + */ +int task_nice(const struct task_struct *p) +{ + return TASK_NICE(p); +} +EXPORT_SYMBOL_GPL(task_nice); + +/** + * idle_cpu - is a given cpu idle currently? + * @cpu: the processor in question. + */ +int idle_cpu(int cpu) +{ + return cpu_curr(cpu) == cpu_rq(cpu)->idle; +} + +/** + * idle_task - return the idle task for a given cpu. + * @cpu: the processor in question. + */ +struct task_struct *idle_task(int cpu) +{ + return cpu_rq(cpu)->idle; +} + +/** + * find_process_by_pid - find a process with a matching PID value. + * @pid: the pid in question. + */ +static inline struct task_struct *find_process_by_pid(pid_t pid) +{ + return pid ? find_task_by_pid(pid) : current; +} + +/* Actually do priority change: must hold rq lock. */ +static void __setscheduler(struct task_struct *p, int policy, int prio) +{ + BUG_ON(p->array); + + p->policy = policy; + p->rt_priority = prio; + p->normal_prio = normal_prio(p); + /* we are holding p->pi_lock already */ + p->prio = rt_mutex_getprio(p); + /* + * SCHED_BATCH tasks are treated as perpetual CPU hogs: + */ + if (policy == SCHED_BATCH) + p->sleep_avg = 0; + set_load_weight(p); +} + +/** + * sched_setscheduler - change the scheduling policy and/or RT priority of + * a thread. + * @p: the task in question. + * @policy: new policy. + * @param: structure containing the new RT priority. + * + * NOTE: the task may be already dead + */ +int sched_setscheduler(struct task_struct *p, int policy, + struct sched_param *param) +{ + int retval, oldprio, oldpolicy = -1; + struct prio_array *array; + unsigned long flags; + struct rq *rq; + + /* may grab non-irq protected spin_locks */ + BUG_ON(in_interrupt()); +recheck: + /* double check policy once rq lock held */ + if (policy < 0) + policy = oldpolicy = p->policy; + else if (policy != SCHED_FIFO && policy != SCHED_RR && + policy != SCHED_NORMAL && policy != SCHED_BATCH) + return -EINVAL; + /* + * Valid priorities for SCHED_FIFO and SCHED_RR are + * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and + * SCHED_BATCH is 0. + */ + if (param->sched_priority < 0 || + (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || + (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) + return -EINVAL; + if (is_rt_policy(policy) != (param->sched_priority != 0)) + return -EINVAL; + + /* + * Allow unprivileged RT tasks to decrease priority: + */ + if (!capable(CAP_SYS_NICE)) { + if (is_rt_policy(policy)) { + unsigned long rlim_rtprio; + unsigned long flags; + + if (!lock_task_sighand(p, &flags)) + return -ESRCH; + rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; + unlock_task_sighand(p, &flags); + + /* can't set/change the rt policy */ + if (policy != p->policy && !rlim_rtprio) + return -EPERM; + + /* can't increase priority */ + if (param->sched_priority > p->rt_priority && + param->sched_priority > rlim_rtprio) + return -EPERM; + } + + /* can't change other user's priorities */ + if ((current->euid != p->euid) && + (current->euid != p->uid)) + return -EPERM; + } + + retval = security_task_setscheduler(p, policy, param); + if (retval) + return retval; + /* + * make sure no PI-waiters arrive (or leave) while we are + * changing the priority of the task: + */ + spin_lock_irqsave(&p->pi_lock, flags); + /* + * To be able to change p->policy safely, the apropriate + * runqueue lock must be held. + */ + rq = __task_rq_lock(p); + /* recheck policy now with rq lock held */ + if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { + policy = oldpolicy = -1; + __task_rq_unlock(rq); + spin_unlock_irqrestore(&p->pi_lock, flags); + goto recheck; + } + array = p->array; + if (array) + deactivate_task(p, rq); + oldprio = p->prio; + __setscheduler(p, policy, param->sched_priority); + if (array) { + vx_activate_task(p); + __activate_task(p, rq); + /* + * Reschedule if we are currently running on this runqueue and + * our priority decreased, or if we are not currently running on + * this runqueue and our priority is higher than the current's + */ + if (task_running(rq, p)) { + if (p->prio > oldprio) + resched_task(rq->curr); + } else if (TASK_PREEMPTS_CURR(p, rq)) + resched_task(rq->curr); + } + __task_rq_unlock(rq); + spin_unlock_irqrestore(&p->pi_lock, flags); + + rt_mutex_adjust_pi(p); + + return 0; +} +EXPORT_SYMBOL_GPL(sched_setscheduler); + +static int +do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) +{ + struct sched_param lparam; + struct task_struct *p; + int retval; + + if (!param || pid < 0) + return -EINVAL; + if (copy_from_user(&lparam, param, sizeof(struct sched_param))) + return -EFAULT; + + rcu_read_lock(); + retval = -ESRCH; + p = find_process_by_pid(pid); + if (p != NULL) + retval = sched_setscheduler(p, policy, &lparam); + rcu_read_unlock(); + + return retval; +} + +/** + * sys_sched_setscheduler - set/change the scheduler policy and RT priority + * @pid: the pid in question. + * @policy: new policy. + * @param: structure containing the new RT priority. + */ +asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, + struct sched_param __user *param) +{ + /* negative values for policy are not valid */ + if (policy < 0) + return -EINVAL; + + return do_sched_setscheduler(pid, policy, param); +} + +/** + * sys_sched_setparam - set/change the RT priority of a thread + * @pid: the pid in question. + * @param: structure containing the new RT priority. + */ +asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) +{ + return do_sched_setscheduler(pid, -1, param); +} + +/** + * sys_sched_getscheduler - get the policy (scheduling class) of a thread + * @pid: the pid in question. + */ +asmlinkage long sys_sched_getscheduler(pid_t pid) +{ + struct task_struct *p; + int retval = -EINVAL; + + if (pid < 0) + goto out_nounlock; + + retval = -ESRCH; + read_lock(&tasklist_lock); + p = find_process_by_pid(pid); + if (p) { + retval = security_task_getscheduler(p); + if (!retval) + retval = p->policy; + } + read_unlock(&tasklist_lock); + +out_nounlock: + return retval; +} + +/** + * sys_sched_getscheduler - get the RT priority of a thread + * @pid: the pid in question. + * @param: structure containing the RT priority. + */ +asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) +{ + struct sched_param lp; + struct task_struct *p; + int retval = -EINVAL; + + if (!param || pid < 0) + goto out_nounlock; + + read_lock(&tasklist_lock); + p = find_process_by_pid(pid); + retval = -ESRCH; + if (!p) + goto out_unlock; + + retval = security_task_getscheduler(p); + if (retval) + goto out_unlock; + + lp.sched_priority = p->rt_priority; + read_unlock(&tasklist_lock); + + /* + * This one might sleep, we cannot do it with a spinlock held ... + */ + retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; + +out_nounlock: + return retval; + +out_unlock: + read_unlock(&tasklist_lock); + return retval; +} + +long sched_setaffinity(pid_t pid, cpumask_t new_mask) +{ + cpumask_t cpus_allowed; + struct task_struct *p; + int retval; + + lock_cpu_hotplug(); + read_lock(&tasklist_lock); + + p = find_process_by_pid(pid); + if (!p) { + read_unlock(&tasklist_lock); + unlock_cpu_hotplug(); + return -ESRCH; + } + + /* + * It is not safe to call set_cpus_allowed with the + * tasklist_lock held. We will bump the task_struct's + * usage count and then drop tasklist_lock. + */ + get_task_struct(p); + read_unlock(&tasklist_lock); + + retval = -EPERM; + if ((current->euid != p->euid) && (current->euid != p->uid) && + !capable(CAP_SYS_NICE)) + goto out_unlock; + + retval = security_task_setscheduler(p, 0, NULL); + if (retval) + goto out_unlock; + + cpus_allowed = cpuset_cpus_allowed(p); + cpus_and(new_mask, new_mask, cpus_allowed); + retval = set_cpus_allowed(p, new_mask); + +out_unlock: + put_task_struct(p); + unlock_cpu_hotplug(); + return retval; +} + +static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, + cpumask_t *new_mask) +{ + if (len < sizeof(cpumask_t)) { + memset(new_mask, 0, sizeof(cpumask_t)); + } else if (len > sizeof(cpumask_t)) { + len = sizeof(cpumask_t); + } + return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; +} + +/** + * sys_sched_setaffinity - set the cpu affinity of a process + * @pid: pid of the process + * @len: length in bytes of the bitmask pointed to by user_mask_ptr + * @user_mask_ptr: user-space pointer to the new cpu mask + */ +asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, + unsigned long __user *user_mask_ptr) +{ + cpumask_t new_mask; + int retval; + + retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); + if (retval) + return retval; + + return sched_setaffinity(pid, new_mask); +} + +/* + * Represents all cpu's present in the system + * In systems capable of hotplug, this map could dynamically grow + * as new cpu's are detected in the system via any platform specific + * method, such as ACPI for e.g. + */ + +cpumask_t cpu_present_map __read_mostly; +EXPORT_SYMBOL(cpu_present_map); + +#ifndef CONFIG_SMP +cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; +EXPORT_SYMBOL(cpu_online_map); + +cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; +EXPORT_SYMBOL(cpu_possible_map); +#endif + +long sched_getaffinity(pid_t pid, cpumask_t *mask) +{ + struct task_struct *p; + int retval; + + lock_cpu_hotplug(); + read_lock(&tasklist_lock); + + retval = -ESRCH; + p = find_process_by_pid(pid); + if (!p) + goto out_unlock; + + retval = security_task_getscheduler(p); + if (retval) + goto out_unlock; + + cpus_and(*mask, p->cpus_allowed, cpu_online_map); + +out_unlock: + read_unlock(&tasklist_lock); + unlock_cpu_hotplug(); + if (retval) + return retval; + + return 0; +} + +/** + * sys_sched_getaffinity - get the cpu affinity of a process + * @pid: pid of the process + * @len: length in bytes of the bitmask pointed to by user_mask_ptr + * @user_mask_ptr: user-space pointer to hold the current cpu mask + */ +asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, + unsigned long __user *user_mask_ptr) +{ + int ret; + cpumask_t mask; + + if (len < sizeof(cpumask_t)) + return -EINVAL; + + ret = sched_getaffinity(pid, &mask); + if (ret < 0) + return ret; + + if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) + return -EFAULT; + + return sizeof(cpumask_t); +} + +/** + * sys_sched_yield - yield the current processor to other threads. + * + * this function yields the current CPU by moving the calling thread + * to the expired array. If there are no other threads running on this + * CPU then this function will return. + */ +asmlinkage long sys_sched_yield(void) +{ + struct rq *rq = this_rq_lock(); + struct prio_array *array = current->array, *target = rq->expired; + + schedstat_inc(rq, yld_cnt); + /* + * We implement yielding by moving the task into the expired + * queue. + * + * (special rule: RT tasks will just roundrobin in the active + * array.) + */ + if (rt_task(current)) + target = rq->active; + + if (array->nr_active == 1) { + schedstat_inc(rq, yld_act_empty); + if (!rq->expired->nr_active) + schedstat_inc(rq, yld_both_empty); + } else if (!rq->expired->nr_active) + schedstat_inc(rq, yld_exp_empty); + + if (array != target) { + dequeue_task(current, array); + enqueue_task(current, target); + } else + /* + * requeue_task is cheaper so perform that if possible. + */ + requeue_task(current, array); + + /* + * Since we are going to call schedule() anyway, there's + * no need to preempt or enable interrupts: + */ + __release(rq->lock); + spin_release(&rq->lock.dep_map, 1, _THIS_IP_); + _raw_spin_unlock(&rq->lock); + preempt_enable_no_resched(); + + schedule(); + + return 0; +} + +static void __cond_resched(void) +{ +#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP + __might_sleep(__FILE__, __LINE__); +#endif + /* + * The BKS might be reacquired before we have dropped + * PREEMPT_ACTIVE, which could trigger a second + * cond_resched() call. + */ + do { + add_preempt_count(PREEMPT_ACTIVE); + schedule(); + sub_preempt_count(PREEMPT_ACTIVE); + } while (need_resched()); +} + +int __sched cond_resched(void) +{ + if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && + system_state == SYSTEM_RUNNING) { + __cond_resched(); + return 1; + } + return 0; +} +EXPORT_SYMBOL(cond_resched); + +/* + * cond_resched_lock() - if a reschedule is pending, drop the given lock, + * call schedule, and on return reacquire the lock. + * + * This works OK both with and without CONFIG_PREEMPT. We do strange low-level + * operations here to prevent schedule() from being called twice (once via + * spin_unlock(), once by hand). + */ +int cond_resched_lock(spinlock_t *lock) +{ + int ret = 0; + + if (need_lockbreak(lock)) { + spin_unlock(lock); + cpu_relax(); + ret = 1; + spin_lock(lock); + } + if (need_resched() && system_state == SYSTEM_RUNNING) { + spin_release(&lock->dep_map, 1, _THIS_IP_); + _raw_spin_unlock(lock); + preempt_enable_no_resched(); + __cond_resched(); + ret = 1; + spin_lock(lock); + } + return ret; +} +EXPORT_SYMBOL(cond_resched_lock); + +int __sched cond_resched_softirq(void) +{ + BUG_ON(!in_softirq()); + + if (need_resched() && system_state == SYSTEM_RUNNING) { + raw_local_irq_disable(); + _local_bh_enable(); + raw_local_irq_enable(); + __cond_resched(); + local_bh_disable(); + return 1; + } + return 0; +} +EXPORT_SYMBOL(cond_resched_softirq); + +/** + * yield - yield the current processor to other threads. + * + * this is a shortcut for kernel-space yielding - it marks the + * thread runnable and calls sys_sched_yield(). + */ +void __sched yield(void) +{ + set_current_state(TASK_RUNNING); + sys_sched_yield(); +} +EXPORT_SYMBOL(yield); + +/* + * This task is about to go to sleep on IO. Increment rq->nr_iowait so + * that process accounting knows that this is a task in IO wait state. + * + * But don't do that if it is a deliberate, throttling IO wait (this task + * has set its backing_dev_info: the queue against which it should throttle) + */ +void __sched io_schedule(void) +{ + struct rq *rq = &__raw_get_cpu_var(runqueues); + + delayacct_blkio_start(); + atomic_inc(&rq->nr_iowait); + schedule(); + atomic_dec(&rq->nr_iowait); + delayacct_blkio_end(); +} +EXPORT_SYMBOL(io_schedule); + +long __sched io_schedule_timeout(long timeout) +{ + struct rq *rq = &__raw_get_cpu_var(runqueues); + long ret; + + delayacct_blkio_start(); + atomic_inc(&rq->nr_iowait); + ret = schedule_timeout(timeout); + atomic_dec(&rq->nr_iowait); + delayacct_blkio_end(); + return ret; +} + +/** + * sys_sched_get_priority_max - return maximum RT priority. + * @policy: scheduling class. + * + * this syscall returns the maximum rt_priority that can be used + * by a given scheduling class. + */ +asmlinkage long sys_sched_get_priority_max(int policy) +{ + int ret = -EINVAL; + + switch (policy) { + case SCHED_FIFO: + case SCHED_RR: + ret = MAX_USER_RT_PRIO-1; + break; + case SCHED_NORMAL: + case SCHED_BATCH: + ret = 0; + break; + } + return ret; +} + +/** + * sys_sched_get_priority_min - return minimum RT priority. + * @policy: scheduling class. + * + * this syscall returns the minimum rt_priority that can be used + * by a given scheduling class. + */ +asmlinkage long sys_sched_get_priority_min(int policy) +{ + int ret = -EINVAL; + + switch (policy) { + case SCHED_FIFO: + case SCHED_RR: + ret = 1; + break; + case SCHED_NORMAL: + case SCHED_BATCH: + ret = 0; + } + return ret; +} + +/** + * sys_sched_rr_get_interval - return the default timeslice of a process. + * @pid: pid of the process. + * @interval: userspace pointer to the timeslice value. + * + * this syscall writes the default timeslice value of a given process + * into the user-space timespec buffer. A value of '0' means infinity. + */ +asmlinkage +long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) +{ + struct task_struct *p; + int retval = -EINVAL; + struct timespec t; + + if (pid < 0) + goto out_nounlock; + + retval = -ESRCH; + read_lock(&tasklist_lock); + p = find_process_by_pid(pid); + if (!p) + goto out_unlock; + + retval = security_task_getscheduler(p); + if (retval) + goto out_unlock; + + jiffies_to_timespec(p->policy == SCHED_FIFO ? + 0 : task_timeslice(p), &t); + read_unlock(&tasklist_lock); + retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; +out_nounlock: + return retval; +out_unlock: + read_unlock(&tasklist_lock); + return retval; +} + +static inline struct task_struct *eldest_child(struct task_struct *p) +{ + if (list_empty(&p->children)) + return NULL; + return list_entry(p->children.next,struct task_struct,sibling); +} + +static inline struct task_struct *older_sibling(struct task_struct *p) +{ + if (p->sibling.prev==&p->parent->children) + return NULL; + return list_entry(p->sibling.prev,struct task_struct,sibling); +} + +static inline struct task_struct *younger_sibling(struct task_struct *p) +{ + if (p->sibling.next==&p->parent->children) + return NULL; + return list_entry(p->sibling.next,struct task_struct,sibling); +} + +static const char stat_nam[] = "RSDTtZX"; + +static void show_task(struct task_struct *p) +{ + struct task_struct *relative; + unsigned long free = 0; + unsigned state; + + state = p->state ? __ffs(p->state) + 1 : 0; + printk("%-13.13s %c", p->comm, + state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); +#if (BITS_PER_LONG == 32) + if (state == TASK_RUNNING) + printk(" running "); + else + printk(" %08lX ", thread_saved_pc(p)); +#else + if (state == TASK_RUNNING) + printk(" running task "); + else + printk(" %016lx ", thread_saved_pc(p)); +#endif +#ifdef CONFIG_DEBUG_STACK_USAGE + { + unsigned long *n = end_of_stack(p); + while (!*n) + n++; + free = (unsigned long)n - (unsigned long)end_of_stack(p); + } +#endif + printk("%5lu %5d %6d ", free, p->pid, p->parent->pid); + if ((relative = eldest_child(p))) + printk("%5d ", relative->pid); + else + printk(" "); + if ((relative = younger_sibling(p))) + printk("%7d", relative->pid); + else + printk(" "); + if ((relative = older_sibling(p))) + printk(" %5d", relative->pid); + else + printk(" "); + if (!p->mm) + printk(" (L-TLB)\n"); + else + printk(" (NOTLB)\n"); + + if (state != TASK_RUNNING) + show_stack(p, NULL); +} + +void show_state_filter(unsigned long state_filter) +{ + struct task_struct *g, *p; + +#if (BITS_PER_LONG == 32) + printk("\n" + " free sibling\n"); + printk(" task PC stack pid father child younger older\n"); +#else + printk("\n" + " free sibling\n"); + printk(" task PC stack pid father child younger older\n"); +#endif + read_lock(&tasklist_lock); + do_each_thread(g, p) { + /* + * reset the NMI-timeout, listing all files on a slow + * console might take alot of time: + */ + touch_nmi_watchdog(); + if (p->state & state_filter) + show_task(p); + } while_each_thread(g, p); + + read_unlock(&tasklist_lock); + /* + * Only show locks if all tasks are dumped: + */ + if (state_filter == -1) + debug_show_all_locks(); +} + +/** + * init_idle - set up an idle thread for a given CPU + * @idle: task in question + * @cpu: cpu the idle task belongs to + * + * NOTE: this function does not set the idle thread's NEED_RESCHED + * flag, to make booting more robust. + */ +void __cpuinit init_idle(struct task_struct *idle, int cpu) +{ + struct rq *rq = cpu_rq(cpu); + unsigned long flags; + + idle->timestamp = sched_clock(); + idle->sleep_avg = 0; + idle->array = NULL; + idle->prio = idle->normal_prio = MAX_PRIO; + idle->state = TASK_RUNNING; + idle->cpus_allowed = cpumask_of_cpu(cpu); + set_task_cpu(idle, cpu); + + spin_lock_irqsave(&rq->lock, flags); + rq->curr = rq->idle = idle; +#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) + idle->oncpu = 1; +#endif + spin_unlock_irqrestore(&rq->lock, flags); + + /* Set the preempt count _outside_ the spinlocks! */ +#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) + task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); +#else + task_thread_info(idle)->preempt_count = 0; +#endif +} + +/* + * In a system that switches off the HZ timer nohz_cpu_mask + * indicates which cpus entered this state. This is used + * in the rcu update to wait only for active cpus. For system + * which do not switch off the HZ timer nohz_cpu_mask should + * always be CPU_MASK_NONE. + */ +cpumask_t nohz_cpu_mask = CPU_MASK_NONE; + +#ifdef CONFIG_SMP +/* + * This is how migration works: + * + * 1) we queue a struct migration_req structure in the source CPU's + * runqueue and wake up that CPU's migration thread. + * 2) we down() the locked semaphore => thread blocks. + * 3) migration thread wakes up (implicitly it forces the migrated + * thread off the CPU) + * 4) it gets the migration request and checks whether the migrated + * task is still in the wrong runqueue. + * 5) if it's in the wrong runqueue then the migration thread removes + * it and puts it into the right queue. + * 6) migration thread up()s the semaphore. + * 7) we wake up and the migration is done. + */ + +/* + * Change a given task's CPU affinity. Migrate the thread to a + * proper CPU and schedule it away if the CPU it's executing on + * is removed from the allowed bitmask. + * + * NOTE: the caller must have a valid reference to the task, the + * task must not exit() & deallocate itself prematurely. The + * call is not atomic; no spinlocks may be held. + */ +int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) +{ + struct migration_req req; + unsigned long flags; + struct rq *rq; + int ret = 0; + + rq = task_rq_lock(p, &flags); + if (!cpus_intersects(new_mask, cpu_online_map)) { + ret = -EINVAL; + goto out; + } + + p->cpus_allowed = new_mask; + /* Can the task run on the task's current CPU? If so, we're done */ + if (cpu_isset(task_cpu(p), new_mask)) + goto out; + + if (migrate_task(p, any_online_cpu(new_mask), &req)) { + /* Need help from migration thread: drop lock and wait. */ + task_rq_unlock(rq, &flags); + wake_up_process(rq->migration_thread); + wait_for_completion(&req.done); + tlb_migrate_finish(p->mm); + return 0; + } +out: + task_rq_unlock(rq, &flags); + + return ret; +} +EXPORT_SYMBOL_GPL(set_cpus_allowed); + +/* + * Move (not current) task off this cpu, onto dest cpu. We're doing + * this because either it can't run here any more (set_cpus_allowed() + * away from this CPU, or CPU going down), or because we're + * attempting to rebalance this task on exec (sched_exec). + * + * So we race with normal scheduler movements, but that's OK, as long + * as the task is no longer on this CPU. + * + * Returns non-zero if task was successfully migrated. + */ +static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) +{ + struct rq *rq_dest, *rq_src; + int ret = 0; + + if (unlikely(cpu_is_offline(dest_cpu))) + return ret; + + rq_src = cpu_rq(src_cpu); + rq_dest = cpu_rq(dest_cpu); + + double_rq_lock(rq_src, rq_dest); + /* Already moved. */ + if (task_cpu(p) != src_cpu) + goto out; + /* Affinity changed (again). */ + if (!cpu_isset(dest_cpu, p->cpus_allowed)) + goto out; + + set_task_cpu(p, dest_cpu); + if (p->array) { + /* + * Sync timestamp with rq_dest's before activating. + * The same thing could be achieved by doing this step + * afterwards, and pretending it was a local activate. + * This way is cleaner and logically correct. + */ + p->timestamp = p->timestamp - rq_src->most_recent_timestamp + + rq_dest->most_recent_timestamp; + deactivate_task(p, rq_src); + vx_activate_task(p); + __activate_task(p, rq_dest); + if (TASK_PREEMPTS_CURR(p, rq_dest)) + resched_task(rq_dest->curr); + } + ret = 1; +out: + double_rq_unlock(rq_src, rq_dest); + return ret; +} + +/* + * migration_thread - this is a highprio system thread that performs + * thread migration by bumping thread off CPU then 'pushing' onto + * another runqueue. + */ +static int migration_thread(void *data) +{ + int cpu = (long)data; + struct rq *rq; + + rq = cpu_rq(cpu); + BUG_ON(rq->migration_thread != current); + + set_current_state(TASK_INTERRUPTIBLE); + while (!kthread_should_stop()) { + struct migration_req *req; + struct list_head *head; + + try_to_freeze(); + + spin_lock_irq(&rq->lock); + + if (cpu_is_offline(cpu)) { + spin_unlock_irq(&rq->lock); + goto wait_to_die; + } + + if (rq->active_balance) { + active_load_balance(rq, cpu); + rq->active_balance = 0; + } + + head = &rq->migration_queue; + + if (list_empty(head)) { + spin_unlock_irq(&rq->lock); + schedule(); + set_current_state(TASK_INTERRUPTIBLE); + continue; + } + req = list_entry(head->next, struct migration_req, list); + list_del_init(head->next); + + spin_unlock(&rq->lock); + __migrate_task(req->task, cpu, req->dest_cpu); + local_irq_enable(); + + complete(&req->done); + } + __set_current_state(TASK_RUNNING); + return 0; + +wait_to_die: + /* Wait for kthread_stop */ + set_current_state(TASK_INTERRUPTIBLE); + while (!kthread_should_stop()) { + schedule(); + set_current_state(TASK_INTERRUPTIBLE); + } + __set_current_state(TASK_RUNNING); + return 0; +} + +#ifdef CONFIG_HOTPLUG_CPU +/* + * Figure out where task on dead CPU should go, use force if neccessary. + * NOTE: interrupts should be disabled by the caller + */ +static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) +{ + unsigned long flags; + cpumask_t mask; + struct rq *rq; + int dest_cpu; + +restart: + /* On same node? */ + mask = node_to_cpumask(cpu_to_node(dead_cpu)); + cpus_and(mask, mask, p->cpus_allowed); + dest_cpu = any_online_cpu(mask); + + /* On any allowed CPU? */ + if (dest_cpu == NR_CPUS) + dest_cpu = any_online_cpu(p->cpus_allowed); + + /* No more Mr. Nice Guy. */ + if (dest_cpu == NR_CPUS) { + rq = task_rq_lock(p, &flags); + cpus_setall(p->cpus_allowed); + dest_cpu = any_online_cpu(p->cpus_allowed); + task_rq_unlock(rq, &flags); + + /* + * Don't tell them about moving exiting tasks or + * kernel threads (both mm NULL), since they never + * leave kernel. + */ + if (p->mm && printk_ratelimit()) + printk(KERN_INFO "process %d (%s) no " + "longer affine to cpu%d\n", + p->pid, p->comm, dead_cpu); + } + if (!__migrate_task(p, dead_cpu, dest_cpu)) + goto restart; +} + +/* + * While a dead CPU has no uninterruptible tasks queued at this point, + * it might still have a nonzero ->nr_uninterruptible counter, because + * for performance reasons the counter is not stricly tracking tasks to + * their home CPUs. So we just add the counter to another CPU's counter, + * to keep the global sum constant after CPU-down: + */ +static void migrate_nr_uninterruptible(struct rq *rq_src) +{ + struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); + unsigned long flags; + + local_irq_save(flags); + double_rq_lock(rq_src, rq_dest); + rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; + rq_src->nr_uninterruptible = 0; + double_rq_unlock(rq_src, rq_dest); + local_irq_restore(flags); +} + +/* Run through task list and migrate tasks from the dead cpu. */ +static void migrate_live_tasks(int src_cpu) +{ + struct task_struct *p, *t; + + write_lock_irq(&tasklist_lock); + + do_each_thread(t, p) { + if (p == current) + continue; + + if (task_cpu(p) == src_cpu) + move_task_off_dead_cpu(src_cpu, p); + } while_each_thread(t, p); + + write_unlock_irq(&tasklist_lock); +} + +/* Schedules idle task to be the next runnable task on current CPU. + * It does so by boosting its priority to highest possible and adding it to + * the _front_ of the runqueue. Used by CPU offline code. + */ +void sched_idle_next(void) +{ + int this_cpu = smp_processor_id(); + struct rq *rq = cpu_rq(this_cpu); + struct task_struct *p = rq->idle; + unsigned long flags; + + /* cpu has to be offline */ + BUG_ON(cpu_online(this_cpu)); /* - * We play safe to avoid deadlocks. + * Strictly not necessary since rest of the CPUs are stopped by now + * and interrupts disabled on the current cpu. */ - read_lock_irq(&tasklist_lock); + spin_lock_irqsave(&rq->lock, flags); - p = find_process_by_pid(pid); + __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); - retval = -ESRCH; - if (!p) - goto out_unlock_tasklist; + /* Add idle task to the _front_ of its priority queue: */ + __activate_idle_task(p, rq); + + spin_unlock_irqrestore(&rq->lock, flags); +} + +/* + * Ensures that the idle task is using init_mm right before its cpu goes + * offline. + */ +void idle_task_exit(void) +{ + struct mm_struct *mm = current->active_mm; + + BUG_ON(cpu_online(smp_processor_id())); + + if (mm != &init_mm) + switch_mm(mm, &init_mm, current); + mmdrop(mm); +} + +/* called under rq->lock with disabled interrupts */ +static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) +{ + struct rq *rq = cpu_rq(dead_cpu); + + /* Must be exiting, otherwise would be on tasklist. */ + BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD); + + /* Cannot have done final schedule yet: would have vanished. */ + BUG_ON(p->state == TASK_DEAD); + + get_task_struct(p); /* - * To be able to change p->policy safely, the apropriate - * runqueue lock must be held. + * Drop lock around migration; if someone else moves it, + * that's OK. No task can be added to this CPU, so iteration is + * fine. + * NOTE: interrupts should be left disabled --dev@ */ - rq = task_rq_lock(p, &flags); + spin_unlock(&rq->lock); + move_task_off_dead_cpu(dead_cpu, p); + spin_lock(&rq->lock); + + put_task_struct(p); +} + +/* release_task() removes task from tasklist, so we won't find dead tasks. */ +static void migrate_dead_tasks(unsigned int dead_cpu) +{ + struct rq *rq = cpu_rq(dead_cpu); + unsigned int arr, i; + + for (arr = 0; arr < 2; arr++) { + for (i = 0; i < MAX_PRIO; i++) { + struct list_head *list = &rq->arrays[arr].queue[i]; + + while (!list_empty(list)) + migrate_dead(dead_cpu, list_entry(list->next, + struct task_struct, run_list)); + } + } +} +#endif /* CONFIG_HOTPLUG_CPU */ + +/* + * migration_call - callback that gets triggered when a CPU is added. + * Here we can start up the necessary migration thread for the new CPU. + */ +static int __cpuinit +migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) +{ + struct task_struct *p; + int cpu = (long)hcpu; + unsigned long flags; + struct rq *rq; + + switch (action) { + case CPU_UP_PREPARE: + p = kthread_create(migration_thread, hcpu, "migration/%d",cpu); + if (IS_ERR(p)) + return NOTIFY_BAD; + p->flags |= PF_NOFREEZE; + kthread_bind(p, cpu); + /* Must be high prio: stop_machine expects to yield to it. */ + rq = task_rq_lock(p, &flags); + __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); + task_rq_unlock(rq, &flags); + cpu_rq(cpu)->migration_thread = p; + break; + + case CPU_ONLINE: + /* Strictly unneccessary, as first user will wake it. */ + wake_up_process(cpu_rq(cpu)->migration_thread); + break; + +#ifdef CONFIG_HOTPLUG_CPU + case CPU_UP_CANCELED: + if (!cpu_rq(cpu)->migration_thread) + break; + /* Unbind it from offline cpu so it can run. Fall thru. */ + kthread_bind(cpu_rq(cpu)->migration_thread, + any_online_cpu(cpu_online_map)); + kthread_stop(cpu_rq(cpu)->migration_thread); + cpu_rq(cpu)->migration_thread = NULL; + break; + + case CPU_DEAD: + migrate_live_tasks(cpu); + rq = cpu_rq(cpu); + kthread_stop(rq->migration_thread); + rq->migration_thread = NULL; + /* Idle task back to normal (off runqueue, low prio) */ + rq = task_rq_lock(rq->idle, &flags); + deactivate_task(rq->idle, rq); + rq->idle->static_prio = MAX_PRIO; + __setscheduler(rq->idle, SCHED_NORMAL, 0); + migrate_dead_tasks(cpu); + task_rq_unlock(rq, &flags); + migrate_nr_uninterruptible(rq); + BUG_ON(rq->nr_running != 0); + + /* No need to migrate the tasks: it was best-effort if + * they didn't do lock_cpu_hotplug(). Just wake up + * the requestors. */ + spin_lock_irq(&rq->lock); + while (!list_empty(&rq->migration_queue)) { + struct migration_req *req; + + req = list_entry(rq->migration_queue.next, + struct migration_req, list); + list_del_init(&req->list); + complete(&req->done); + } + spin_unlock_irq(&rq->lock); + break; +#endif + } + return NOTIFY_OK; +} + +/* Register at highest priority so that task migration (migrate_all_tasks) + * happens before everything else. + */ +static struct notifier_block __cpuinitdata migration_notifier = { + .notifier_call = migration_call, + .priority = 10 +}; + +int __init migration_init(void) +{ + void *cpu = (void *)(long)smp_processor_id(); + int err; + + /* Start one for the boot CPU: */ + err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); + BUG_ON(err == NOTIFY_BAD); + migration_call(&migration_notifier, CPU_ONLINE, cpu); + register_cpu_notifier(&migration_notifier); + + return 0; +} +#endif + +#ifdef CONFIG_SMP +#undef SCHED_DOMAIN_DEBUG +#ifdef SCHED_DOMAIN_DEBUG +static void sched_domain_debug(struct sched_domain *sd, int cpu) +{ + int level = 0; + + if (!sd) { + printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); + return; + } + + printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); + + do { + int i; + char str[NR_CPUS]; + struct sched_group *group = sd->groups; + cpumask_t groupmask; + + cpumask_scnprintf(str, NR_CPUS, sd->span); + cpus_clear(groupmask); + + printk(KERN_DEBUG); + for (i = 0; i < level + 1; i++) + printk(" "); + printk("domain %d: ", level); + + if (!(sd->flags & SD_LOAD_BALANCE)) { + printk("does not load-balance\n"); + if (sd->parent) + printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" + " has parent"); + break; + } + + printk("span %s\n", str); + + if (!cpu_isset(cpu, sd->span)) + printk(KERN_ERR "ERROR: domain->span does not contain " + "CPU%d\n", cpu); + if (!cpu_isset(cpu, group->cpumask)) + printk(KERN_ERR "ERROR: domain->groups does not contain" + " CPU%d\n", cpu); + + printk(KERN_DEBUG); + for (i = 0; i < level + 2; i++) + printk(" "); + printk("groups:"); + do { + if (!group) { + printk("\n"); + printk(KERN_ERR "ERROR: group is NULL\n"); + break; + } + + if (!group->cpu_power) { + printk("\n"); + printk(KERN_ERR "ERROR: domain->cpu_power not " + "set\n"); + } + + if (!cpus_weight(group->cpumask)) { + printk("\n"); + printk(KERN_ERR "ERROR: empty group\n"); + } + + if (cpus_intersects(groupmask, group->cpumask)) { + printk("\n"); + printk(KERN_ERR "ERROR: repeated CPUs\n"); + } + + cpus_or(groupmask, groupmask, group->cpumask); + + cpumask_scnprintf(str, NR_CPUS, group->cpumask); + printk(" %s", str); + + group = group->next; + } while (group != sd->groups); + printk("\n"); + + if (!cpus_equal(sd->span, groupmask)) + printk(KERN_ERR "ERROR: groups don't span " + "domain->span\n"); + + level++; + sd = sd->parent; + if (!sd) + continue; + + if (!cpus_subset(groupmask, sd->span)) + printk(KERN_ERR "ERROR: parent span is not a superset " + "of domain->span\n"); + + } while (sd); +} +#else +# define sched_domain_debug(sd, cpu) do { } while (0) +#endif + +static int sd_degenerate(struct sched_domain *sd) +{ + if (cpus_weight(sd->span) == 1) + return 1; + + /* Following flags need at least 2 groups */ + if (sd->flags & (SD_LOAD_BALANCE | + SD_BALANCE_NEWIDLE | + SD_BALANCE_FORK | + SD_BALANCE_EXEC | + SD_SHARE_CPUPOWER | + SD_SHARE_PKG_RESOURCES)) { + if (sd->groups != sd->groups->next) + return 0; + } + + /* Following flags don't use groups */ + if (sd->flags & (SD_WAKE_IDLE | + SD_WAKE_AFFINE | + SD_WAKE_BALANCE)) + return 0; + + return 1; +} + +static int +sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) +{ + unsigned long cflags = sd->flags, pflags = parent->flags; + + if (sd_degenerate(parent)) + return 1; + + if (!cpus_equal(sd->span, parent->span)) + return 0; + + /* Does parent contain flags not in child? */ + /* WAKE_BALANCE is a subset of WAKE_AFFINE */ + if (cflags & SD_WAKE_AFFINE) + pflags &= ~SD_WAKE_BALANCE; + /* Flags needing groups don't count if only 1 group in parent */ + if (parent->groups == parent->groups->next) { + pflags &= ~(SD_LOAD_BALANCE | + SD_BALANCE_NEWIDLE | + SD_BALANCE_FORK | + SD_BALANCE_EXEC | + SD_SHARE_CPUPOWER | + SD_SHARE_PKG_RESOURCES); + } + if (~cflags & pflags) + return 0; + + return 1; +} + +/* + * Attach the domain 'sd' to 'cpu' as its base domain. Callers must + * hold the hotplug lock. + */ +static void cpu_attach_domain(struct sched_domain *sd, int cpu) +{ + struct rq *rq = cpu_rq(cpu); + struct sched_domain *tmp; + + /* Remove the sched domains which do not contribute to scheduling. */ + for (tmp = sd; tmp; tmp = tmp->parent) { + struct sched_domain *parent = tmp->parent; + if (!parent) + break; + if (sd_parent_degenerate(tmp, parent)) { + tmp->parent = parent->parent; + if (parent->parent) + parent->parent->child = tmp; + } + } + + if (sd && sd_degenerate(sd)) { + sd = sd->parent; + if (sd) + sd->child = NULL; + } + + sched_domain_debug(sd, cpu); + + rcu_assign_pointer(rq->sd, sd); +} + +/* cpus with isolated domains */ +static cpumask_t cpu_isolated_map = CPU_MASK_NONE; + +/* Setup the mask of cpus configured for isolated domains */ +static int __init isolated_cpu_setup(char *str) +{ + int ints[NR_CPUS], i; + + str = get_options(str, ARRAY_SIZE(ints), ints); + cpus_clear(cpu_isolated_map); + for (i = 1; i <= ints[0]; i++) + if (ints[i] < NR_CPUS) + cpu_set(ints[i], cpu_isolated_map); + return 1; +} + +__setup ("isolcpus=", isolated_cpu_setup); + +/* + * init_sched_build_groups takes the cpumask we wish to span, and a pointer + * to a function which identifies what group(along with sched group) a CPU + * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS + * (due to the fact that we keep track of groups covered with a cpumask_t). + * + * init_sched_build_groups will build a circular linked list of the groups + * covered by the given span, and will set each group's ->cpumask correctly, + * and ->cpu_power to 0. + */ +static void +init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, + int (*group_fn)(int cpu, const cpumask_t *cpu_map, + struct sched_group **sg)) +{ + struct sched_group *first = NULL, *last = NULL; + cpumask_t covered = CPU_MASK_NONE; + int i; + + for_each_cpu_mask(i, span) { + struct sched_group *sg; + int group = group_fn(i, cpu_map, &sg); + int j; + + if (cpu_isset(i, covered)) + continue; + + sg->cpumask = CPU_MASK_NONE; + sg->cpu_power = 0; + + for_each_cpu_mask(j, span) { + if (group_fn(j, cpu_map, NULL) != group) + continue; + + cpu_set(j, covered); + cpu_set(j, sg->cpumask); + } + if (!first) + first = sg; + if (last) + last->next = sg; + last = sg; + } + last->next = first; +} + +#define SD_NODES_PER_DOMAIN 16 + +/* + * Self-tuning task migration cost measurement between source and target CPUs. + * + * This is done by measuring the cost of manipulating buffers of varying + * sizes. For a given buffer-size here are the steps that are taken: + * + * 1) the source CPU reads+dirties a shared buffer + * 2) the target CPU reads+dirties the same shared buffer + * + * We measure how long they take, in the following 4 scenarios: + * + * - source: CPU1, target: CPU2 | cost1 + * - source: CPU2, target: CPU1 | cost2 + * - source: CPU1, target: CPU1 | cost3 + * - source: CPU2, target: CPU2 | cost4 + * + * We then calculate the cost3+cost4-cost1-cost2 difference - this is + * the cost of migration. + * + * We then start off from a small buffer-size and iterate up to larger + * buffer sizes, in 5% steps - measuring each buffer-size separately, and + * doing a maximum search for the cost. (The maximum cost for a migration + * normally occurs when the working set size is around the effective cache + * size.) + */ +#define SEARCH_SCOPE 2 +#define MIN_CACHE_SIZE (64*1024U) +#define DEFAULT_CACHE_SIZE (5*1024*1024U) +#define ITERATIONS 1 +#define SIZE_THRESH 130 +#define COST_THRESH 130 + +/* + * The migration cost is a function of 'domain distance'. Domain + * distance is the number of steps a CPU has to iterate down its + * domain tree to share a domain with the other CPU. The farther + * two CPUs are from each other, the larger the distance gets. + * + * Note that we use the distance only to cache measurement results, + * the distance value is not used numerically otherwise. When two + * CPUs have the same distance it is assumed that the migration + * cost is the same. (this is a simplification but quite practical) + */ +#define MAX_DOMAIN_DISTANCE 32 + +static unsigned long long migration_cost[MAX_DOMAIN_DISTANCE] = + { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] = +/* + * Architectures may override the migration cost and thus avoid + * boot-time calibration. Unit is nanoseconds. Mostly useful for + * virtualized hardware: + */ +#ifdef CONFIG_DEFAULT_MIGRATION_COST + CONFIG_DEFAULT_MIGRATION_COST +#else + -1LL +#endif +}; + +/* + * Allow override of migration cost - in units of microseconds. + * E.g. migration_cost=1000,2000,3000 will set up a level-1 cost + * of 1 msec, level-2 cost of 2 msecs and level3 cost of 3 msecs: + */ +static int __init migration_cost_setup(char *str) +{ + int ints[MAX_DOMAIN_DISTANCE+1], i; + + str = get_options(str, ARRAY_SIZE(ints), ints); + + printk("#ints: %d\n", ints[0]); + for (i = 1; i <= ints[0]; i++) { + migration_cost[i-1] = (unsigned long long)ints[i]*1000; + printk("migration_cost[%d]: %Ld\n", i-1, migration_cost[i-1]); + } + return 1; +} + +__setup ("migration_cost=", migration_cost_setup); - if (policy < 0) - policy = p->policy; - else { - retval = -EINVAL; - if (policy != SCHED_FIFO && policy != SCHED_RR && - policy != SCHED_NORMAL) - goto out_unlock; - } +/* + * Global multiplier (divisor) for migration-cutoff values, + * in percentiles. E.g. use a value of 150 to get 1.5 times + * longer cache-hot cutoff times. + * + * (We scale it from 100 to 128 to long long handling easier.) + */ - /* - * Valid priorities for SCHED_FIFO and SCHED_RR are - * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL is 0. - */ - retval = -EINVAL; - if (lp.sched_priority < 0 || lp.sched_priority > MAX_USER_RT_PRIO-1) - goto out_unlock; - if ((policy == SCHED_NORMAL) != (lp.sched_priority == 0)) - goto out_unlock; +#define MIGRATION_FACTOR_SCALE 128 - retval = -EPERM; - if ((policy == SCHED_FIFO || policy == SCHED_RR) && - !capable(CAP_SYS_NICE)) - goto out_unlock; - if ((current->euid != p->euid) && (current->euid != p->uid) && - !capable(CAP_SYS_NICE)) - goto out_unlock; +static unsigned int migration_factor = MIGRATION_FACTOR_SCALE; - retval = security_task_setscheduler(p, policy, &lp); - if (retval) - goto out_unlock; +static int __init setup_migration_factor(char *str) +{ + get_option(&str, &migration_factor); + migration_factor = migration_factor * MIGRATION_FACTOR_SCALE / 100; + return 1; +} - array = p->array; - if (array) - deactivate_task(p, task_rq(p)); - retval = 0; - oldprio = p->prio; - __setscheduler(p, policy, lp.sched_priority); - if (array) { - __activate_task(p, task_rq(p)); - /* - * Reschedule if we are currently running on this runqueue and - * our priority decreased, or if we are not currently running on - * this runqueue and our priority is higher than the current's - */ - if (task_running(rq, p)) { - if (p->prio > oldprio) - resched_task(rq->curr); - } else if (p->prio < rq->curr->prio) - resched_task(rq->curr); +__setup("migration_factor=", setup_migration_factor); + +/* + * Estimated distance of two CPUs, measured via the number of domains + * we have to pass for the two CPUs to be in the same span: + */ +static unsigned long domain_distance(int cpu1, int cpu2) +{ + unsigned long distance = 0; + struct sched_domain *sd; + + for_each_domain(cpu1, sd) { + WARN_ON(!cpu_isset(cpu1, sd->span)); + if (cpu_isset(cpu2, sd->span)) + return distance; + distance++; + } + if (distance >= MAX_DOMAIN_DISTANCE) { + WARN_ON(1); + distance = MAX_DOMAIN_DISTANCE-1; } -out_unlock: - task_rq_unlock(rq, &flags); -out_unlock_tasklist: - read_unlock_irq(&tasklist_lock); + return distance; +} -out_nounlock: - return retval; +static unsigned int migration_debug; + +static int __init setup_migration_debug(char *str) +{ + get_option(&str, &migration_debug); + return 1; } -/** - * sys_sched_setscheduler - set/change the scheduler policy and RT priority - * @pid: the pid in question. - * @policy: new policy - * @param: structure containing the new RT priority. +__setup("migration_debug=", setup_migration_debug); + +/* + * Maximum cache-size that the scheduler should try to measure. + * Architectures with larger caches should tune this up during + * bootup. Gets used in the domain-setup code (i.e. during SMP + * bootup). */ -asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, - struct sched_param __user *param) +unsigned int max_cache_size; + +static int __init setup_max_cache_size(char *str) { - return setscheduler(pid, policy, param); + get_option(&str, &max_cache_size); + return 1; } -/** - * sys_sched_setparam - set/change the RT priority of a thread - * @pid: the pid in question. - * @param: structure containing the new RT priority. +__setup("max_cache_size=", setup_max_cache_size); + +/* + * Dirty a big buffer in a hard-to-predict (for the L2 cache) way. This + * is the operation that is timed, so we try to generate unpredictable + * cachemisses that still end up filling the L2 cache: */ -asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) +static void touch_cache(void *__cache, unsigned long __size) { - return setscheduler(pid, -1, param); + unsigned long size = __size / sizeof(long); + unsigned long chunk1 = size / 3; + unsigned long chunk2 = 2 * size / 3; + unsigned long *cache = __cache; + int i; + + for (i = 0; i < size/6; i += 8) { + switch (i % 6) { + case 0: cache[i]++; + case 1: cache[size-1-i]++; + case 2: cache[chunk1-i]++; + case 3: cache[chunk1+i]++; + case 4: cache[chunk2-i]++; + case 5: cache[chunk2+i]++; + } + } } -/** - * sys_sched_getscheduler - get the policy (scheduling class) of a thread - * @pid: the pid in question. +/* + * Measure the cache-cost of one task migration. Returns in units of nsec. */ -asmlinkage long sys_sched_getscheduler(pid_t pid) +static unsigned long long +measure_one(void *cache, unsigned long size, int source, int target) { - int retval = -EINVAL; - task_t *p; + cpumask_t mask, saved_mask; + unsigned long long t0, t1, t2, t3, cost; - if (pid < 0) - goto out_nounlock; + saved_mask = current->cpus_allowed; - retval = -ESRCH; - read_lock(&tasklist_lock); - p = find_process_by_pid(pid); - if (p) { - retval = security_task_getscheduler(p); - if (!retval) - retval = p->policy; - } - read_unlock(&tasklist_lock); + /* + * Flush source caches to RAM and invalidate them: + */ + sched_cacheflush(); -out_nounlock: - return retval; + /* + * Migrate to the source CPU: + */ + mask = cpumask_of_cpu(source); + set_cpus_allowed(current, mask); + WARN_ON(smp_processor_id() != source); + + /* + * Dirty the working set: + */ + t0 = sched_clock(); + touch_cache(cache, size); + t1 = sched_clock(); + + /* + * Migrate to the target CPU, dirty the L2 cache and access + * the shared buffer. (which represents the working set + * of a migrated task.) + */ + mask = cpumask_of_cpu(target); + set_cpus_allowed(current, mask); + WARN_ON(smp_processor_id() != target); + + t2 = sched_clock(); + touch_cache(cache, size); + t3 = sched_clock(); + + cost = t1-t0 + t3-t2; + + if (migration_debug >= 2) + printk("[%d->%d]: %8Ld %8Ld %8Ld => %10Ld.\n", + source, target, t1-t0, t1-t0, t3-t2, cost); + /* + * Flush target caches to RAM and invalidate them: + */ + sched_cacheflush(); + + set_cpus_allowed(current, saved_mask); + + return cost; } -/** - * sys_sched_getscheduler - get the RT priority of a thread - * @pid: the pid in question. - * @param: structure containing the RT priority. +/* + * Measure a series of task migrations and return the average + * result. Since this code runs early during bootup the system + * is 'undisturbed' and the average latency makes sense. + * + * The algorithm in essence auto-detects the relevant cache-size, + * so it will properly detect different cachesizes for different + * cache-hierarchies, depending on how the CPUs are connected. + * + * Architectures can prime the upper limit of the search range via + * max_cache_size, otherwise the search range defaults to 20MB...64K. */ -asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) +static unsigned long long +measure_cost(int cpu1, int cpu2, void *cache, unsigned int size) { - struct sched_param lp; - int retval = -EINVAL; - task_t *p; - - if (!param || pid < 0) - goto out_nounlock; + unsigned long long cost1, cost2; + int i; - read_lock(&tasklist_lock); - p = find_process_by_pid(pid); - retval = -ESRCH; - if (!p) - goto out_unlock; + /* + * Measure the migration cost of 'size' bytes, over an + * average of 10 runs: + * + * (We perturb the cache size by a small (0..4k) + * value to compensate size/alignment related artifacts. + * We also subtract the cost of the operation done on + * the same CPU.) + */ + cost1 = 0; - retval = security_task_getscheduler(p); - if (retval) - goto out_unlock; + /* + * dry run, to make sure we start off cache-cold on cpu1, + * and to get any vmalloc pagefaults in advance: + */ + measure_one(cache, size, cpu1, cpu2); + for (i = 0; i < ITERATIONS; i++) + cost1 += measure_one(cache, size - i * 1024, cpu1, cpu2); - lp.sched_priority = p->rt_priority; - read_unlock(&tasklist_lock); + measure_one(cache, size, cpu2, cpu1); + for (i = 0; i < ITERATIONS; i++) + cost1 += measure_one(cache, size - i * 1024, cpu2, cpu1); /* - * This one might sleep, we cannot do it with a spinlock held ... + * (We measure the non-migrating [cached] cost on both + * cpu1 and cpu2, to handle CPUs with different speeds) */ - retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; + cost2 = 0; -out_nounlock: - return retval; + measure_one(cache, size, cpu1, cpu1); + for (i = 0; i < ITERATIONS; i++) + cost2 += measure_one(cache, size - i * 1024, cpu1, cpu1); -out_unlock: - read_unlock(&tasklist_lock); - return retval; + measure_one(cache, size, cpu2, cpu2); + for (i = 0; i < ITERATIONS; i++) + cost2 += measure_one(cache, size - i * 1024, cpu2, cpu2); + + /* + * Get the per-iteration migration cost: + */ + do_div(cost1, 2 * ITERATIONS); + do_div(cost2, 2 * ITERATIONS); + + return cost1 - cost2; } -/** - * sys_sched_setaffinity - set the cpu affinity of a process - * @pid: pid of the process - * @len: length in bytes of the bitmask pointed to by user_mask_ptr - * @user_mask_ptr: user-space pointer to the new cpu mask - */ -asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, - unsigned long __user *user_mask_ptr) +static unsigned long long measure_migration_cost(int cpu1, int cpu2) { - cpumask_t new_mask; - int retval; - task_t *p; + unsigned long long max_cost = 0, fluct = 0, avg_fluct = 0; + unsigned int max_size, size, size_found = 0; + long long cost = 0, prev_cost; + void *cache; - if (len < sizeof(new_mask)) - return -EINVAL; + /* + * Search from max_cache_size*5 down to 64K - the real relevant + * cachesize has to lie somewhere inbetween. + */ + if (max_cache_size) { + max_size = max(max_cache_size * SEARCH_SCOPE, MIN_CACHE_SIZE); + size = max(max_cache_size / SEARCH_SCOPE, MIN_CACHE_SIZE); + } else { + /* + * Since we have no estimation about the relevant + * search range + */ + max_size = DEFAULT_CACHE_SIZE * SEARCH_SCOPE; + size = MIN_CACHE_SIZE; + } - if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask))) - return -EFAULT; + if (!cpu_online(cpu1) || !cpu_online(cpu2)) { + printk("cpu %d and %d not both online!\n", cpu1, cpu2); + return 0; + } - lock_cpu_hotplug(); - read_lock(&tasklist_lock); + /* + * Allocate the working set: + */ + cache = vmalloc(max_size); + if (!cache) { + printk("could not vmalloc %d bytes for cache!\n", 2 * max_size); + return 1000000; /* return 1 msec on very small boxen */ + } - p = find_process_by_pid(pid); - if (!p) { - read_unlock(&tasklist_lock); - unlock_cpu_hotplug(); - return -ESRCH; + while (size <= max_size) { + prev_cost = cost; + cost = measure_cost(cpu1, cpu2, cache, size); + + /* + * Update the max: + */ + if (cost > 0) { + if (max_cost < cost) { + max_cost = cost; + size_found = size; + } + } + /* + * Calculate average fluctuation, we use this to prevent + * noise from triggering an early break out of the loop: + */ + fluct = abs(cost - prev_cost); + avg_fluct = (avg_fluct + fluct)/2; + + if (migration_debug) + printk("-> [%d][%d][%7d] %3ld.%ld [%3ld.%ld] (%ld): " + "(%8Ld %8Ld)\n", + cpu1, cpu2, size, + (long)cost / 1000000, + ((long)cost / 100000) % 10, + (long)max_cost / 1000000, + ((long)max_cost / 100000) % 10, + domain_distance(cpu1, cpu2), + cost, avg_fluct); + + /* + * If we iterated at least 20% past the previous maximum, + * and the cost has dropped by more than 20% already, + * (taking fluctuations into account) then we assume to + * have found the maximum and break out of the loop early: + */ + if (size_found && (size*100 > size_found*SIZE_THRESH)) + if (cost+avg_fluct <= 0 || + max_cost*100 > (cost+avg_fluct)*COST_THRESH) { + + if (migration_debug) + printk("-> found max.\n"); + break; + } + /* + * Increase the cachesize in 10% steps: + */ + size = size * 10 / 9; } + if (migration_debug) + printk("[%d][%d] working set size found: %d, cost: %Ld\n", + cpu1, cpu2, size_found, max_cost); + + vfree(cache); + /* - * It is not safe to call set_cpus_allowed with the - * tasklist_lock held. We will bump the task_struct's - * usage count and then drop tasklist_lock. + * A task is considered 'cache cold' if at least 2 times + * the worst-case cost of migration has passed. + * + * (this limit is only listened to if the load-balancing + * situation is 'nice' - if there is a large imbalance we + * ignore it for the sake of CPU utilization and + * processing fairness.) */ - get_task_struct(p); - read_unlock(&tasklist_lock); + return 2 * max_cost * migration_factor / MIGRATION_FACTOR_SCALE; +} - retval = -EPERM; - if ((current->euid != p->euid) && (current->euid != p->uid) && - !capable(CAP_SYS_NICE)) - goto out_unlock; +static void calibrate_migration_costs(const cpumask_t *cpu_map) +{ + int cpu1 = -1, cpu2 = -1, cpu, orig_cpu = raw_smp_processor_id(); + unsigned long j0, j1, distance, max_distance = 0; + struct sched_domain *sd; - retval = set_cpus_allowed(p, new_mask); + j0 = jiffies; -out_unlock: - put_task_struct(p); - unlock_cpu_hotplug(); - return retval; + /* + * First pass - calculate the cacheflush times: + */ + for_each_cpu_mask(cpu1, *cpu_map) { + for_each_cpu_mask(cpu2, *cpu_map) { + if (cpu1 == cpu2) + continue; + distance = domain_distance(cpu1, cpu2); + max_distance = max(max_distance, distance); + /* + * No result cached yet? + */ + if (migration_cost[distance] == -1LL) + migration_cost[distance] = + measure_migration_cost(cpu1, cpu2); + } + } + /* + * Second pass - update the sched domain hierarchy with + * the new cache-hot-time estimations: + */ + for_each_cpu_mask(cpu, *cpu_map) { + distance = 0; + for_each_domain(cpu, sd) { + sd->cache_hot_time = migration_cost[distance]; + distance++; + } + } + /* + * Print the matrix: + */ + if (migration_debug) + printk("migration: max_cache_size: %d, cpu: %d MHz:\n", + max_cache_size, +#ifdef CONFIG_X86 + cpu_khz/1000 +#else + -1 +#endif + ); + if (system_state == SYSTEM_BOOTING && num_online_cpus() > 1) { + printk("migration_cost="); + for (distance = 0; distance <= max_distance; distance++) { + if (distance) + printk(","); + printk("%ld", (long)migration_cost[distance] / 1000); + } + printk("\n"); + } + j1 = jiffies; + if (migration_debug) + printk("migration: %ld seconds\n", (j1-j0) / HZ); + + /* + * Move back to the original CPU. NUMA-Q gets confused + * if we migrate to another quad during bootup. + */ + if (raw_smp_processor_id() != orig_cpu) { + cpumask_t mask = cpumask_of_cpu(orig_cpu), + saved_mask = current->cpus_allowed; + + set_cpus_allowed(current, mask); + set_cpus_allowed(current, saved_mask); + } } +#ifdef CONFIG_NUMA + /** - * sys_sched_getaffinity - get the cpu affinity of a process - * @pid: pid of the process - * @len: length in bytes of the bitmask pointed to by user_mask_ptr - * @user_mask_ptr: user-space pointer to hold the current cpu mask + * find_next_best_node - find the next node to include in a sched_domain + * @node: node whose sched_domain we're building + * @used_nodes: nodes already in the sched_domain + * + * Find the next node to include in a given scheduling domain. Simply + * finds the closest node not already in the @used_nodes map. + * + * Should use nodemask_t. */ -asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, - unsigned long __user *user_mask_ptr) +static int find_next_best_node(int node, unsigned long *used_nodes) { - unsigned int real_len; - cpumask_t mask; - int retval; - task_t *p; + int i, n, val, min_val, best_node = 0; - real_len = sizeof(mask); - if (len < real_len) - return -EINVAL; + min_val = INT_MAX; - read_lock(&tasklist_lock); + for (i = 0; i < MAX_NUMNODES; i++) { + /* Start at @node */ + n = (node + i) % MAX_NUMNODES; - retval = -ESRCH; - p = find_process_by_pid(pid); - if (!p) - goto out_unlock; + if (!nr_cpus_node(n)) + continue; - retval = 0; - cpus_and(mask, p->cpus_allowed, cpu_possible_map); + /* Skip already used nodes */ + if (test_bit(n, used_nodes)) + continue; -out_unlock: - read_unlock(&tasklist_lock); - if (retval) - return retval; - if (copy_to_user(user_mask_ptr, &mask, real_len)) - return -EFAULT; - return real_len; + /* Simple min distance search */ + val = node_distance(node, n); + + if (val < min_val) { + min_val = val; + best_node = n; + } + } + + set_bit(best_node, used_nodes); + return best_node; } /** - * sys_sched_yield - yield the current processor to other threads. + * sched_domain_node_span - get a cpumask for a node's sched_domain + * @node: node whose cpumask we're constructing + * @size: number of nodes to include in this span * - * this function yields the current CPU by moving the calling thread - * to the expired array. If there are no other threads running on this - * CPU then this function will return. + * Given a node, construct a good cpumask for its sched_domain to span. It + * should be one that prevents unnecessary balancing, but also spreads tasks + * out optimally. */ -asmlinkage long sys_sched_yield(void) +static cpumask_t sched_domain_node_span(int node) { - runqueue_t *rq = this_rq_lock(); - prio_array_t *array = current->array; + DECLARE_BITMAP(used_nodes, MAX_NUMNODES); + cpumask_t span, nodemask; + int i; - /* - * We implement yielding by moving the task into the expired - * queue. - * - * (special rule: RT tasks will just roundrobin in the active - * array.) - */ - if (likely(!rt_task(current))) { - dequeue_task(current, array); - enqueue_task(current, rq->expired); - } else { - list_del(¤t->run_list); - list_add_tail(¤t->run_list, array->queue + current->prio); - } - /* - * Since we are going to call schedule() anyway, there's - * no need to preempt: - */ - _raw_spin_unlock(&rq->lock); - preempt_enable_no_resched(); + cpus_clear(span); + bitmap_zero(used_nodes, MAX_NUMNODES); - schedule(); + nodemask = node_to_cpumask(node); + cpus_or(span, span, nodemask); + set_bit(node, used_nodes); - return 0; -} + for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { + int next_node = find_next_best_node(node, used_nodes); -void __sched __cond_resched(void) -{ - set_current_state(TASK_RUNNING); - schedule(); + nodemask = node_to_cpumask(next_node); + cpus_or(span, span, nodemask); + } + + return span; } +#endif -EXPORT_SYMBOL(__cond_resched); +int sched_smt_power_savings = 0, sched_mc_power_savings = 0; -/** - * yield - yield the current processor to other threads. - * - * this is a shortcut for kernel-space yielding - it marks the - * thread runnable and calls sys_sched_yield(). +/* + * SMT sched-domains: */ -void __sched yield(void) +#ifdef CONFIG_SCHED_SMT +static DEFINE_PER_CPU(struct sched_domain, cpu_domains); +static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); + +static int cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, + struct sched_group **sg) { - set_current_state(TASK_RUNNING); - sys_sched_yield(); + if (sg) + *sg = &per_cpu(sched_group_cpus, cpu); + return cpu; } - -EXPORT_SYMBOL(yield); +#endif /* - * This task is about to go to sleep on IO. Increment rq->nr_iowait so - * that process accounting knows that this is a task in IO wait state. - * - * But don't do that if it is a deliberate, throttling IO wait (this task - * has set its backing_dev_info: the queue against which it should throttle) + * multi-core sched-domains: */ -void __sched io_schedule(void) +#ifdef CONFIG_SCHED_MC +static DEFINE_PER_CPU(struct sched_domain, core_domains); +static DEFINE_PER_CPU(struct sched_group, sched_group_core); +#endif + +#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) +static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, + struct sched_group **sg) +{ + int group; + cpumask_t mask = cpu_sibling_map[cpu]; + cpus_and(mask, mask, *cpu_map); + group = first_cpu(mask); + if (sg) + *sg = &per_cpu(sched_group_core, group); + return group; +} +#elif defined(CONFIG_SCHED_MC) +static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, + struct sched_group **sg) { - struct runqueue *rq = this_rq(); + if (sg) + *sg = &per_cpu(sched_group_core, cpu); + return cpu; +} +#endif - atomic_inc(&rq->nr_iowait); - schedule(); - atomic_dec(&rq->nr_iowait); +static DEFINE_PER_CPU(struct sched_domain, phys_domains); +static DEFINE_PER_CPU(struct sched_group, sched_group_phys); + +static int cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, + struct sched_group **sg) +{ + int group; +#ifdef CONFIG_SCHED_MC + cpumask_t mask = cpu_coregroup_map(cpu); + cpus_and(mask, mask, *cpu_map); + group = first_cpu(mask); +#elif defined(CONFIG_SCHED_SMT) + cpumask_t mask = cpu_sibling_map[cpu]; + cpus_and(mask, mask, *cpu_map); + group = first_cpu(mask); +#else + group = cpu; +#endif + if (sg) + *sg = &per_cpu(sched_group_phys, group); + return group; } -EXPORT_SYMBOL(io_schedule); +#ifdef CONFIG_NUMA +/* + * The init_sched_build_groups can't handle what we want to do with node + * groups, so roll our own. Now each node has its own list of groups which + * gets dynamically allocated. + */ +static DEFINE_PER_CPU(struct sched_domain, node_domains); +static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; -long __sched io_schedule_timeout(long timeout) +static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); +static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); + +static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, + struct sched_group **sg) { - struct runqueue *rq = this_rq(); - long ret; + cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); + int group; - atomic_inc(&rq->nr_iowait); - ret = schedule_timeout(timeout); - atomic_dec(&rq->nr_iowait); - return ret; + cpus_and(nodemask, nodemask, *cpu_map); + group = first_cpu(nodemask); + + if (sg) + *sg = &per_cpu(sched_group_allnodes, group); + return group; } -/** - * sys_sched_get_priority_max - return maximum RT priority. - * @policy: scheduling class. - * - * this syscall returns the maximum rt_priority that can be used - * by a given scheduling class. - */ -asmlinkage long sys_sched_get_priority_max(int policy) +static void init_numa_sched_groups_power(struct sched_group *group_head) { - int ret = -EINVAL; + struct sched_group *sg = group_head; + int j; - switch (policy) { - case SCHED_FIFO: - case SCHED_RR: - ret = MAX_USER_RT_PRIO-1; - break; - case SCHED_NORMAL: - ret = 0; - break; + if (!sg) + return; +next_sg: + for_each_cpu_mask(j, sg->cpumask) { + struct sched_domain *sd; + + sd = &per_cpu(phys_domains, j); + if (j != first_cpu(sd->groups->cpumask)) { + /* + * Only add "power" once for each + * physical package. + */ + continue; + } + + sg->cpu_power += sd->groups->cpu_power; } - return ret; + sg = sg->next; + if (sg != group_head) + goto next_sg; } +#endif -/** - * sys_sched_get_priority_min - return minimum RT priority. - * @policy: scheduling class. - * - * this syscall returns the minimum rt_priority that can be used - * by a given scheduling class. - */ -asmlinkage long sys_sched_get_priority_min(int policy) +#ifdef CONFIG_NUMA +/* Free memory allocated for various sched_group structures */ +static void free_sched_groups(const cpumask_t *cpu_map) { - int ret = -EINVAL; + int cpu, i; - switch (policy) { - case SCHED_FIFO: - case SCHED_RR: - ret = 1; - break; - case SCHED_NORMAL: - ret = 0; + for_each_cpu_mask(cpu, *cpu_map) { + struct sched_group **sched_group_nodes + = sched_group_nodes_bycpu[cpu]; + + if (!sched_group_nodes) + continue; + + for (i = 0; i < MAX_NUMNODES; i++) { + cpumask_t nodemask = node_to_cpumask(i); + struct sched_group *oldsg, *sg = sched_group_nodes[i]; + + cpus_and(nodemask, nodemask, *cpu_map); + if (cpus_empty(nodemask)) + continue; + + if (sg == NULL) + continue; + sg = sg->next; +next_sg: + oldsg = sg; + sg = sg->next; + kfree(oldsg); + if (oldsg != sched_group_nodes[i]) + goto next_sg; + } + kfree(sched_group_nodes); + sched_group_nodes_bycpu[cpu] = NULL; } - return ret; } +#else +static void free_sched_groups(const cpumask_t *cpu_map) +{ +} +#endif -/** - * sys_sched_rr_get_interval - return the default timeslice of a process. - * @pid: pid of the process. - * @interval: userspace pointer to the timeslice value. +/* + * Initialize sched groups cpu_power. * - * this syscall writes the default timeslice value of a given process - * into the user-space timespec buffer. A value of '0' means infinity. + * cpu_power indicates the capacity of sched group, which is used while + * distributing the load between different sched groups in a sched domain. + * Typically cpu_power for all the groups in a sched domain will be same unless + * there are asymmetries in the topology. If there are asymmetries, group + * having more cpu_power will pickup more load compared to the group having + * less cpu_power. + * + * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents + * the maximum number of tasks a group can handle in the presence of other idle + * or lightly loaded groups in the same sched domain. */ -asmlinkage -long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) +static void init_sched_groups_power(int cpu, struct sched_domain *sd) { - int retval = -EINVAL; - struct timespec t; - task_t *p; + struct sched_domain *child; + struct sched_group *group; - if (pid < 0) - goto out_nounlock; + WARN_ON(!sd || !sd->groups); - retval = -ESRCH; - read_lock(&tasklist_lock); - p = find_process_by_pid(pid); - if (!p) - goto out_unlock; + if (cpu != first_cpu(sd->groups->cpumask)) + return; - retval = security_task_getscheduler(p); - if (retval) - goto out_unlock; + child = sd->child; - jiffies_to_timespec(p->policy & SCHED_FIFO ? - 0 : task_timeslice(p), &t); - read_unlock(&tasklist_lock); - retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; -out_nounlock: - return retval; -out_unlock: - read_unlock(&tasklist_lock); - return retval; -} + /* + * For perf policy, if the groups in child domain share resources + * (for example cores sharing some portions of the cache hierarchy + * or SMT), then set this domain groups cpu_power such that each group + * can handle only one task, when there are other idle groups in the + * same sched domain. + */ + if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && + (child->flags & + (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { + sd->groups->cpu_power = SCHED_LOAD_SCALE; + return; + } -static inline struct task_struct *eldest_child(struct task_struct *p) -{ - if (list_empty(&p->children)) return NULL; - return list_entry(p->children.next,struct task_struct,sibling); -} + sd->groups->cpu_power = 0; -static inline struct task_struct *older_sibling(struct task_struct *p) -{ - if (p->sibling.prev==&p->parent->children) return NULL; - return list_entry(p->sibling.prev,struct task_struct,sibling); + /* + * add cpu_power of each child group to this groups cpu_power + */ + group = child->groups; + do { + sd->groups->cpu_power += group->cpu_power; + group = group->next; + } while (group != child->groups); } -static inline struct task_struct *younger_sibling(struct task_struct *p) +/* + * Build sched domains for a given set of cpus and attach the sched domains + * to the individual cpus + */ +static int build_sched_domains(const cpumask_t *cpu_map) { - if (p->sibling.next==&p->parent->children) return NULL; - return list_entry(p->sibling.next,struct task_struct,sibling); -} + int i; + struct sched_domain *sd; +#ifdef CONFIG_NUMA + struct sched_group **sched_group_nodes = NULL; + int sd_allnodes = 0; -static void show_task(task_t * p) -{ - task_t *relative; - unsigned state; - unsigned long free = 0; - static const char *stat_nam[] = { "R", "S", "D", "T", "Z", "W" }; + /* + * Allocate the per-node list of sched groups + */ + sched_group_nodes = kzalloc(sizeof(struct sched_group*)*MAX_NUMNODES, + GFP_KERNEL); + if (!sched_group_nodes) { + printk(KERN_WARNING "Can not alloc sched group node list\n"); + return -ENOMEM; + } + sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; +#endif - printk("%-13.13s ", p->comm); - state = p->state ? __ffs(p->state) + 1 : 0; - if (state < ARRAY_SIZE(stat_nam)) - printk(stat_nam[state]); - else - printk("?"); -#if (BITS_PER_LONG == 32) - if (state == TASK_RUNNING) - printk(" running "); - else - printk(" %08lX ", thread_saved_pc(p)); -#else - if (state == TASK_RUNNING) - printk(" running task "); - else - printk(" %016lx ", thread_saved_pc(p)); + /* + * Set up domains for cpus specified by the cpu_map. + */ + for_each_cpu_mask(i, *cpu_map) { + struct sched_domain *sd = NULL, *p; + cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); + + cpus_and(nodemask, nodemask, *cpu_map); + +#ifdef CONFIG_NUMA + if (cpus_weight(*cpu_map) + > SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { + sd = &per_cpu(allnodes_domains, i); + *sd = SD_ALLNODES_INIT; + sd->span = *cpu_map; + cpu_to_allnodes_group(i, cpu_map, &sd->groups); + p = sd; + sd_allnodes = 1; + } else + p = NULL; + + sd = &per_cpu(node_domains, i); + *sd = SD_NODE_INIT; + sd->span = sched_domain_node_span(cpu_to_node(i)); + sd->parent = p; + if (p) + p->child = sd; + cpus_and(sd->span, sd->span, *cpu_map); #endif -#ifdef CONFIG_DEBUG_STACK_USAGE - { - unsigned long * n = (unsigned long *) (p->thread_info+1); - while (!*n) - n++; - free = (unsigned long) n - (unsigned long)(p->thread_info+1); + + p = sd; + sd = &per_cpu(phys_domains, i); + *sd = SD_CPU_INIT; + sd->span = nodemask; + sd->parent = p; + if (p) + p->child = sd; + cpu_to_phys_group(i, cpu_map, &sd->groups); + +#ifdef CONFIG_SCHED_MC + p = sd; + sd = &per_cpu(core_domains, i); + *sd = SD_MC_INIT; + sd->span = cpu_coregroup_map(i); + cpus_and(sd->span, sd->span, *cpu_map); + sd->parent = p; + p->child = sd; + cpu_to_core_group(i, cpu_map, &sd->groups); +#endif + +#ifdef CONFIG_SCHED_SMT + p = sd; + sd = &per_cpu(cpu_domains, i); + *sd = SD_SIBLING_INIT; + sd->span = cpu_sibling_map[i]; + cpus_and(sd->span, sd->span, *cpu_map); + sd->parent = p; + p->child = sd; + cpu_to_cpu_group(i, cpu_map, &sd->groups); +#endif + } + +#ifdef CONFIG_SCHED_SMT + /* Set up CPU (sibling) groups */ + for_each_cpu_mask(i, *cpu_map) { + cpumask_t this_sibling_map = cpu_sibling_map[i]; + cpus_and(this_sibling_map, this_sibling_map, *cpu_map); + if (i != first_cpu(this_sibling_map)) + continue; + + init_sched_build_groups(this_sibling_map, cpu_map, &cpu_to_cpu_group); } #endif - printk("%5lu %5d %6d ", free, p->pid, p->parent->pid); - if ((relative = eldest_child(p))) - printk("%5d ", relative->pid); - else - printk(" "); - if ((relative = younger_sibling(p))) - printk("%7d", relative->pid); - else - printk(" "); - if ((relative = older_sibling(p))) - printk(" %5d", relative->pid); - else - printk(" "); - if (!p->mm) - printk(" (L-TLB)\n"); - else - printk(" (NOTLB)\n"); - if (state != TASK_RUNNING) - show_stack(p, NULL); -} +#ifdef CONFIG_SCHED_MC + /* Set up multi-core groups */ + for_each_cpu_mask(i, *cpu_map) { + cpumask_t this_core_map = cpu_coregroup_map(i); + cpus_and(this_core_map, this_core_map, *cpu_map); + if (i != first_cpu(this_core_map)) + continue; + init_sched_build_groups(this_core_map, cpu_map, &cpu_to_core_group); + } +#endif -void show_state(void) -{ - task_t *g, *p; -#if (BITS_PER_LONG == 32) - printk("\n" - " sibling\n"); - printk(" task PC pid father child younger older\n"); -#else - printk("\n" - " sibling\n"); - printk(" task PC pid father child younger older\n"); + /* Set up physical groups */ + for (i = 0; i < MAX_NUMNODES; i++) { + cpumask_t nodemask = node_to_cpumask(i); + + cpus_and(nodemask, nodemask, *cpu_map); + if (cpus_empty(nodemask)) + continue; + + init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); + } + +#ifdef CONFIG_NUMA + /* Set up node groups */ + if (sd_allnodes) + init_sched_build_groups(*cpu_map, cpu_map, &cpu_to_allnodes_group); + + for (i = 0; i < MAX_NUMNODES; i++) { + /* Set up node groups */ + struct sched_group *sg, *prev; + cpumask_t nodemask = node_to_cpumask(i); + cpumask_t domainspan; + cpumask_t covered = CPU_MASK_NONE; + int j; + + cpus_and(nodemask, nodemask, *cpu_map); + if (cpus_empty(nodemask)) { + sched_group_nodes[i] = NULL; + continue; + } + + domainspan = sched_domain_node_span(i); + cpus_and(domainspan, domainspan, *cpu_map); + + sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); + if (!sg) { + printk(KERN_WARNING "Can not alloc domain group for " + "node %d\n", i); + goto error; + } + sched_group_nodes[i] = sg; + for_each_cpu_mask(j, nodemask) { + struct sched_domain *sd; + sd = &per_cpu(node_domains, j); + sd->groups = sg; + } + sg->cpu_power = 0; + sg->cpumask = nodemask; + sg->next = sg; + cpus_or(covered, covered, nodemask); + prev = sg; + + for (j = 0; j < MAX_NUMNODES; j++) { + cpumask_t tmp, notcovered; + int n = (i + j) % MAX_NUMNODES; + + cpus_complement(notcovered, covered); + cpus_and(tmp, notcovered, *cpu_map); + cpus_and(tmp, tmp, domainspan); + if (cpus_empty(tmp)) + break; + + nodemask = node_to_cpumask(n); + cpus_and(tmp, tmp, nodemask); + if (cpus_empty(tmp)) + continue; + + sg = kmalloc_node(sizeof(struct sched_group), + GFP_KERNEL, i); + if (!sg) { + printk(KERN_WARNING + "Can not alloc domain group for node %d\n", j); + goto error; + } + sg->cpu_power = 0; + sg->cpumask = tmp; + sg->next = prev->next; + cpus_or(covered, covered, tmp); + prev->next = sg; + prev = sg; + } + } +#endif + + /* Calculate CPU power for physical packages and nodes */ +#ifdef CONFIG_SCHED_SMT + for_each_cpu_mask(i, *cpu_map) { + sd = &per_cpu(cpu_domains, i); + init_sched_groups_power(i, sd); + } +#endif +#ifdef CONFIG_SCHED_MC + for_each_cpu_mask(i, *cpu_map) { + sd = &per_cpu(core_domains, i); + init_sched_groups_power(i, sd); + } #endif - read_lock(&tasklist_lock); - do_each_thread(g, p) { - /* - * reset the NMI-timeout, listing all files on a slow - * console might take alot of time: - */ - touch_nmi_watchdog(); - show_task(p); - } while_each_thread(g, p); - read_unlock(&tasklist_lock); -} + for_each_cpu_mask(i, *cpu_map) { + sd = &per_cpu(phys_domains, i); + init_sched_groups_power(i, sd); + } -void __init init_idle(task_t *idle, int cpu) -{ - runqueue_t *idle_rq = cpu_rq(cpu), *rq = cpu_rq(task_cpu(idle)); - unsigned long flags; +#ifdef CONFIG_NUMA + for (i = 0; i < MAX_NUMNODES; i++) + init_numa_sched_groups_power(sched_group_nodes[i]); - local_irq_save(flags); - double_rq_lock(idle_rq, rq); + if (sd_allnodes) { + struct sched_group *sg; - idle_rq->curr = idle_rq->idle = idle; - deactivate_task(idle, rq); - idle->array = NULL; - idle->prio = MAX_PRIO; - idle->state = TASK_RUNNING; - set_task_cpu(idle, cpu); - double_rq_unlock(idle_rq, rq); - set_tsk_need_resched(idle); - local_irq_restore(flags); + cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); + init_numa_sched_groups_power(sg); + } +#endif - /* Set the preempt count _outside_ the spinlocks! */ -#ifdef CONFIG_PREEMPT - idle->thread_info->preempt_count = (idle->lock_depth >= 0); + /* Attach the domains */ + for_each_cpu_mask(i, *cpu_map) { + struct sched_domain *sd; +#ifdef CONFIG_SCHED_SMT + sd = &per_cpu(cpu_domains, i); +#elif defined(CONFIG_SCHED_MC) + sd = &per_cpu(core_domains, i); #else - idle->thread_info->preempt_count = 0; + sd = &per_cpu(phys_domains, i); #endif -} - -/* - * In a system that switches off the HZ timer idle_cpu_mask - * indicates which cpus entered this state. This is used - * in the rcu update to wait only for active cpus. For system - * which do not switch off the HZ timer idle_cpu_mask should - * always be CPU_MASK_NONE. - */ -cpumask_t idle_cpu_mask = CPU_MASK_NONE; + cpu_attach_domain(sd, i); + } + /* + * Tune cache-hot values: + */ + calibrate_migration_costs(cpu_map); -#ifdef CONFIG_SMP -/* - * This is how migration works: - * - * 1) we queue a migration_req_t structure in the source CPU's - * runqueue and wake up that CPU's migration thread. - * 2) we down() the locked semaphore => thread blocks. - * 3) migration thread wakes up (implicitly it forces the migrated - * thread off the CPU) - * 4) it gets the migration request and checks whether the migrated - * task is still in the wrong runqueue. - * 5) if it's in the wrong runqueue then the migration thread removes - * it and puts it into the right queue. - * 6) migration thread up()s the semaphore. - * 7) we wake up and the migration is done. - */ + return 0; +#ifdef CONFIG_NUMA +error: + free_sched_groups(cpu_map); + return -ENOMEM; +#endif +} /* - * Change a given task's CPU affinity. Migrate the thread to a - * proper CPU and schedule it away if the CPU it's executing on - * is removed from the allowed bitmask. - * - * NOTE: the caller must have a valid reference to the task, the - * task must not exit() & deallocate itself prematurely. The - * call is not atomic; no spinlocks may be held. + * Set up scheduler domains and groups. Callers must hold the hotplug lock. */ -int set_cpus_allowed(task_t *p, cpumask_t new_mask) +static int arch_init_sched_domains(const cpumask_t *cpu_map) { - unsigned long flags; - int ret = 0; - migration_req_t req; - runqueue_t *rq; + cpumask_t cpu_default_map; + int err; - rq = task_rq_lock(p, &flags); - if (any_online_cpu(new_mask) == NR_CPUS) { - ret = -EINVAL; - goto out; - } + /* + * Setup mask for cpus without special case scheduling requirements. + * For now this just excludes isolated cpus, but could be used to + * exclude other special cases in the future. + */ + cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map); - if (__set_cpus_allowed(p, new_mask, &req)) { - /* Need help from migration thread: drop lock and wait. */ - task_rq_unlock(rq, &flags); - wake_up_process(rq->migration_thread); - wait_for_completion(&req.done); - return 0; - } -out: - task_rq_unlock(rq, &flags); - return ret; -} + err = build_sched_domains(&cpu_default_map); -EXPORT_SYMBOL_GPL(set_cpus_allowed); + return err; +} -/* Move (not current) task off this cpu, onto dest cpu. */ -static void move_task_away(struct task_struct *p, int dest_cpu) +static void arch_destroy_sched_domains(const cpumask_t *cpu_map) { - runqueue_t *rq_dest; - - rq_dest = cpu_rq(dest_cpu); - - double_rq_lock(this_rq(), rq_dest); - if (task_cpu(p) != smp_processor_id()) - goto out; /* Already moved */ + free_sched_groups(cpu_map); +} - set_task_cpu(p, dest_cpu); - if (p->array) { - deactivate_task(p, this_rq()); - activate_task(p, rq_dest); - if (p->prio < rq_dest->curr->prio) - resched_task(rq_dest->curr); - } - p->timestamp = rq_dest->timestamp_last_tick; +/* + * Detach sched domains from a group of cpus specified in cpu_map + * These cpus will now be attached to the NULL domain + */ +static void detach_destroy_domains(const cpumask_t *cpu_map) +{ + int i; -out: - double_rq_unlock(this_rq(), rq_dest); + for_each_cpu_mask(i, *cpu_map) + cpu_attach_domain(NULL, i); + synchronize_sched(); + arch_destroy_sched_domains(cpu_map); } /* - * migration_thread - this is a highprio system thread that performs - * thread migration by bumping thread off CPU then 'pushing' onto - * another runqueue. + * Partition sched domains as specified by the cpumasks below. + * This attaches all cpus from the cpumasks to the NULL domain, + * waits for a RCU quiescent period, recalculates sched + * domain information and then attaches them back to the + * correct sched domains + * Call with hotplug lock held */ -static int migration_thread(void * data) +int partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2) { - runqueue_t *rq; - int cpu = (long)data; + cpumask_t change_map; + int err = 0; - rq = cpu_rq(cpu); - BUG_ON(rq->migration_thread != current); + cpus_and(*partition1, *partition1, cpu_online_map); + cpus_and(*partition2, *partition2, cpu_online_map); + cpus_or(change_map, *partition1, *partition2); - while (!kthread_should_stop()) { - struct list_head *head; - migration_req_t *req; + /* Detach sched domains from all of the affected cpus */ + detach_destroy_domains(&change_map); + if (!cpus_empty(*partition1)) + err = build_sched_domains(partition1); + if (!err && !cpus_empty(*partition2)) + err = build_sched_domains(partition2); - if (current->flags & PF_FREEZE) - refrigerator(PF_FREEZE); + return err; +} - spin_lock_irq(&rq->lock); - head = &rq->migration_queue; - current->state = TASK_INTERRUPTIBLE; - if (list_empty(head)) { - spin_unlock_irq(&rq->lock); - schedule(); - continue; - } - req = list_entry(head->next, migration_req_t, list); - list_del_init(head->next); - spin_unlock(&rq->lock); +#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) +int arch_reinit_sched_domains(void) +{ + int err; - move_task_away(req->task, - any_online_cpu(req->task->cpus_allowed)); - local_irq_enable(); - complete(&req->done); - } - return 0; + lock_cpu_hotplug(); + detach_destroy_domains(&cpu_online_map); + err = arch_init_sched_domains(&cpu_online_map); + unlock_cpu_hotplug(); + + return err; } -#ifdef CONFIG_HOTPLUG_CPU -/* migrate_all_tasks - function to migrate all the tasks from the - * current cpu caller must have already scheduled this to the target - * cpu via set_cpus_allowed. Machine is stopped. */ -void migrate_all_tasks(void) +static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) { - struct task_struct *tsk, *t; - int dest_cpu, src_cpu; - unsigned int node; + int ret; - /* We're nailed to this CPU. */ - src_cpu = smp_processor_id(); + if (buf[0] != '0' && buf[0] != '1') + return -EINVAL; - /* Not required, but here for neatness. */ - write_lock(&tasklist_lock); + if (smt) + sched_smt_power_savings = (buf[0] == '1'); + else + sched_mc_power_savings = (buf[0] == '1'); - /* watch out for per node tasks, let's stay on this node */ - node = cpu_to_node(src_cpu); + ret = arch_reinit_sched_domains(); - do_each_thread(t, tsk) { - cpumask_t mask; - if (tsk == current) - continue; + return ret ? ret : count; +} - if (task_cpu(tsk) != src_cpu) - continue; +int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) +{ + int err = 0; - /* Figure out where this task should go (attempting to - * keep it on-node), and check if it can be migrated - * as-is. NOTE that kernel threads bound to more than - * one online cpu will be migrated. */ - mask = node_to_cpumask(node); - cpus_and(mask, mask, tsk->cpus_allowed); - dest_cpu = any_online_cpu(mask); - if (dest_cpu == NR_CPUS) - dest_cpu = any_online_cpu(tsk->cpus_allowed); - if (dest_cpu == NR_CPUS) { - cpus_clear(tsk->cpus_allowed); - cpus_complement(tsk->cpus_allowed); - dest_cpu = any_online_cpu(tsk->cpus_allowed); - - /* Don't tell them about moving exiting tasks - or kernel threads (both mm NULL), since - they never leave kernel. */ - if (tsk->mm && printk_ratelimit()) - printk(KERN_INFO "process %d (%s) no " - "longer affine to cpu%d\n", - tsk->pid, tsk->comm, src_cpu); - } +#ifdef CONFIG_SCHED_SMT + if (smt_capable()) + err = sysfs_create_file(&cls->kset.kobj, + &attr_sched_smt_power_savings.attr); +#endif +#ifdef CONFIG_SCHED_MC + if (!err && mc_capable()) + err = sysfs_create_file(&cls->kset.kobj, + &attr_sched_mc_power_savings.attr); +#endif + return err; +} +#endif - move_task_away(tsk, dest_cpu); - } while_each_thread(t, tsk); +#ifdef CONFIG_SCHED_MC +static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) +{ + return sprintf(page, "%u\n", sched_mc_power_savings); +} +static ssize_t sched_mc_power_savings_store(struct sys_device *dev, + const char *buf, size_t count) +{ + return sched_power_savings_store(buf, count, 0); +} +SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, + sched_mc_power_savings_store); +#endif - write_unlock(&tasklist_lock); +#ifdef CONFIG_SCHED_SMT +static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) +{ + return sprintf(page, "%u\n", sched_smt_power_savings); } -#endif /* CONFIG_HOTPLUG_CPU */ +static ssize_t sched_smt_power_savings_store(struct sys_device *dev, + const char *buf, size_t count) +{ + return sched_power_savings_store(buf, count, 1); +} +SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, + sched_smt_power_savings_store); +#endif /* - * migration_call - callback that gets triggered when a CPU is added. - * Here we can start up the necessary migration thread for the new CPU. + * Force a reinitialization of the sched domains hierarchy. The domains + * and groups cannot be updated in place without racing with the balancing + * code, so we temporarily attach all running cpus to the NULL domain + * which will prevent rebalancing while the sched domains are recalculated. */ -static int migration_call(struct notifier_block *nfb, unsigned long action, - void *hcpu) +static int update_sched_domains(struct notifier_block *nfb, + unsigned long action, void *hcpu) { - int cpu = (long)hcpu; - struct task_struct *p; - struct runqueue *rq; - unsigned long flags; - switch (action) { case CPU_UP_PREPARE: - p = kthread_create(migration_thread, hcpu, "migration/%d",cpu); - if (IS_ERR(p)) - return NOTIFY_BAD; - kthread_bind(p, cpu); - /* Must be high prio: stop_machine expects to yield to it. */ - rq = task_rq_lock(p, &flags); - __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); - task_rq_unlock(rq, &flags); - cpu_rq(cpu)->migration_thread = p; - break; - case CPU_ONLINE: - /* Strictly unneccessary, as first user will wake it. */ - wake_up_process(cpu_rq(cpu)->migration_thread); - break; -#ifdef CONFIG_HOTPLUG_CPU + case CPU_DOWN_PREPARE: + detach_destroy_domains(&cpu_online_map); + return NOTIFY_OK; + case CPU_UP_CANCELED: - /* Unbind it from offline cpu so it can run. Fall thru. */ - kthread_bind(cpu_rq(cpu)->migration_thread,smp_processor_id()); + case CPU_DOWN_FAILED: + case CPU_ONLINE: case CPU_DEAD: - kthread_stop(cpu_rq(cpu)->migration_thread); - cpu_rq(cpu)->migration_thread = NULL; - BUG_ON(cpu_rq(cpu)->nr_running != 0); - break; -#endif + /* + * Fall through and re-initialise the domains. + */ + break; + default: + return NOTIFY_DONE; } + + /* The hotplug lock is already held by cpu_up/cpu_down */ + arch_init_sched_domains(&cpu_online_map); + return NOTIFY_OK; } -static struct notifier_block __devinitdata migration_notifier = { - .notifier_call = migration_call, -}; +void __init sched_init_smp(void) +{ + cpumask_t non_isolated_cpus; -int __init migration_init(void) + lock_cpu_hotplug(); + arch_init_sched_domains(&cpu_online_map); + cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); + if (cpus_empty(non_isolated_cpus)) + cpu_set(smp_processor_id(), non_isolated_cpus); + unlock_cpu_hotplug(); + /* XXX: Theoretical race here - CPU may be hotplugged now */ + hotcpu_notifier(update_sched_domains, 0); + + /* Move init over to a non-isolated CPU */ + if (set_cpus_allowed(current, non_isolated_cpus) < 0) + BUG(); +} +#else +void __init sched_init_smp(void) { - void *cpu = (void *)(long)smp_processor_id(); - /* Start one for boot CPU. */ - migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); - migration_call(&migration_notifier, CPU_ONLINE, cpu); - register_cpu_notifier(&migration_notifier); - return 0; } -#endif +#endif /* CONFIG_SMP */ -/* - * The 'big kernel lock' - * - * This spinlock is taken and released recursively by lock_kernel() - * and unlock_kernel(). It is transparently dropped and reaquired - * over schedule(). It is used to protect legacy code that hasn't - * been migrated to a proper locking design yet. - * - * Don't use in new code. - * - * Note: spinlock debugging needs this even on !CONFIG_SMP. - */ -spinlock_t kernel_flag __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED; -EXPORT_SYMBOL(kernel_flag); +int in_sched_functions(unsigned long addr) +{ + /* Linker adds these: start and end of __sched functions */ + extern char __sched_text_start[], __sched_text_end[]; + + return in_lock_functions(addr) || + (addr >= (unsigned long)__sched_text_start + && addr < (unsigned long)__sched_text_end); +} void __init sched_init(void) { - runqueue_t *rq; int i, j, k; - for (i = 0; i < NR_CPUS; i++) { - prio_array_t *array; + for_each_possible_cpu(i) { + struct prio_array *array; + struct rq *rq; rq = cpu_rq(i); + spin_lock_init(&rq->lock); + lockdep_set_class(&rq->lock, &rq->rq_lock_key); + rq->nr_running = 0; rq->active = rq->arrays; rq->expired = rq->arrays + 1; rq->best_expired_prio = MAX_PRIO; - spin_lock_init(&rq->lock); +#ifdef CONFIG_SMP + rq->sd = NULL; + for (j = 1; j < 3; j++) + rq->cpu_load[j] = 0; + rq->active_balance = 0; + rq->push_cpu = 0; + rq->cpu = i; + rq->migration_thread = NULL; INIT_LIST_HEAD(&rq->migration_queue); +#endif atomic_set(&rq->nr_iowait, 0); - nr_running_init(rq); - +#ifdef CONFIG_VSERVER_HARDCPU + INIT_LIST_HEAD(&rq->hold_queue); + rq->nr_onhold = 0; +#endif for (j = 0; j < 2; j++) { array = rq->arrays + j; for (k = 0; k < MAX_PRIO; k++) { @@ -2967,40 +7006,50 @@ void __init sched_init(void) __set_bit(MAX_PRIO, array->bitmap); } } - /* - * We have to do a little magic to get the first - * thread right in SMP mode. - */ - rq = this_rq(); - rq->curr = current; - rq->idle = current; - set_task_cpu(current, smp_processor_id()); - wake_up_forked_process(current); - init_timers(); + set_load_weight(&init_task); + +#ifdef CONFIG_SMP + open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); +#endif + +#ifdef CONFIG_RT_MUTEXES + plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); +#endif /* * The boot idle thread does lazy MMU switching as well: */ atomic_inc(&init_mm.mm_count); enter_lazy_tlb(&init_mm, current); + + /* + * 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()); } #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP void __might_sleep(char *file, int line) { -#if defined(in_atomic) +#ifdef in_atomic static unsigned long prev_jiffy; /* ratelimiting */ if ((in_atomic() || irqs_disabled()) && - system_state == SYSTEM_RUNNING) { + system_state == SYSTEM_RUNNING && !oops_in_progress) { if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) return; prev_jiffy = jiffies; - printk(KERN_ERR "Debug: sleeping function called from invalid" + printk(KERN_ERR "BUG: sleeping function called from invalid" " context at %s:%d\n", file, line); printk("in_atomic():%d, irqs_disabled():%d\n", in_atomic(), irqs_disabled()); + debug_show_held_locks(current); + if (irqs_disabled()) + print_irqtrace_events(current); dump_stack(); } #endif @@ -3008,48 +7057,80 @@ void __might_sleep(char *file, int line) EXPORT_SYMBOL(__might_sleep); #endif +#ifdef CONFIG_MAGIC_SYSRQ +void normalize_rt_tasks(void) +{ + struct prio_array *array; + struct task_struct *p; + unsigned long flags; + struct rq *rq; + + read_lock_irq(&tasklist_lock); + for_each_process(p) { + if (!rt_task(p)) + continue; + + spin_lock_irqsave(&p->pi_lock, flags); + rq = __task_rq_lock(p); + + array = p->array; + if (array) + deactivate_task(p, task_rq(p)); + __setscheduler(p, SCHED_NORMAL, 0); + if (array) { + vx_activate_task(p); + __activate_task(p, task_rq(p)); + resched_task(rq->curr); + } + + __task_rq_unlock(rq); + spin_unlock_irqrestore(&p->pi_lock, flags); + } + read_unlock_irq(&tasklist_lock); +} + +#endif /* CONFIG_MAGIC_SYSRQ */ -#if defined(CONFIG_SMP) && defined(CONFIG_PREEMPT) +#ifdef CONFIG_IA64 /* - * This could be a long-held lock. If another CPU holds it for a long time, - * and that CPU is not asked to reschedule then *this* CPU will spin on the - * lock for a long time, even if *this* CPU is asked to reschedule. + * These functions are only useful for the IA64 MCA handling. * - * So what we do here, in the slow (contended) path is to spin on the lock by - * hand while permitting preemption. + * They can only be called when the whole system has been + * stopped - every CPU needs to be quiescent, and no scheduling + * activity can take place. Using them for anything else would + * be a serious bug, and as a result, they aren't even visible + * under any other configuration. + */ + +/** + * curr_task - return the current task for a given cpu. + * @cpu: the processor in question. * - * Called inside preempt_disable(). + * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! */ -void __sched __preempt_spin_lock(spinlock_t *lock) +struct task_struct *curr_task(int cpu) { - if (preempt_count() > 1) { - _raw_spin_lock(lock); - return; - } - do { - preempt_enable(); - while (spin_is_locked(lock)) - cpu_relax(); - preempt_disable(); - } while (!_raw_spin_trylock(lock)); + return cpu_curr(cpu); } -EXPORT_SYMBOL(__preempt_spin_lock); - -void __sched __preempt_write_lock(rwlock_t *lock) +/** + * set_curr_task - set the current task for a given cpu. + * @cpu: the processor in question. + * @p: the task pointer to set. + * + * Description: This function must only be used when non-maskable interrupts + * are serviced on a separate stack. It allows the architecture to switch the + * notion of the current task on a cpu in a non-blocking manner. This function + * must be called with all CPU's synchronized, and interrupts disabled, the + * and caller must save the original value of the current task (see + * curr_task() above) and restore that value before reenabling interrupts and + * re-starting the system. + * + * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! + */ +void set_curr_task(int cpu, struct task_struct *p) { - if (preempt_count() > 1) { - _raw_write_lock(lock); - return; - } - - do { - preempt_enable(); - while (rwlock_is_locked(lock)) - cpu_relax(); - preempt_disable(); - } while (!_raw_write_trylock(lock)); + cpu_curr(cpu) = p; } -EXPORT_SYMBOL(__preempt_write_lock); -#endif /* defined(CONFIG_SMP) && defined(CONFIG_PREEMPT) */ +#endif