]> nv-tegra.nvidia Code Review - linux-2.6.git/blob - kernel/sched.c
Merge branch 'x86-64'
[linux-2.6.git] / kernel / sched.c
1 /*
2  *  kernel/sched.c
3  *
4  *  Kernel scheduler and related syscalls
5  *
6  *  Copyright (C) 1991-2002  Linus Torvalds
7  *
8  *  1996-12-23  Modified by Dave Grothe to fix bugs in semaphores and
9  *              make semaphores SMP safe
10  *  1998-11-19  Implemented schedule_timeout() and related stuff
11  *              by Andrea Arcangeli
12  *  2002-01-04  New ultra-scalable O(1) scheduler by Ingo Molnar:
13  *              hybrid priority-list and round-robin design with
14  *              an array-switch method of distributing timeslices
15  *              and per-CPU runqueues.  Cleanups and useful suggestions
16  *              by Davide Libenzi, preemptible kernel bits by Robert Love.
17  *  2003-09-03  Interactivity tuning by Con Kolivas.
18  *  2004-04-02  Scheduler domains code by Nick Piggin
19  */
20
21 #include <linux/mm.h>
22 #include <linux/module.h>
23 #include <linux/nmi.h>
24 #include <linux/init.h>
25 #include <asm/uaccess.h>
26 #include <linux/highmem.h>
27 #include <linux/smp_lock.h>
28 #include <asm/mmu_context.h>
29 #include <linux/interrupt.h>
30 #include <linux/capability.h>
31 #include <linux/completion.h>
32 #include <linux/kernel_stat.h>
33 #include <linux/security.h>
34 #include <linux/notifier.h>
35 #include <linux/profile.h>
36 #include <linux/suspend.h>
37 #include <linux/vmalloc.h>
38 #include <linux/blkdev.h>
39 #include <linux/delay.h>
40 #include <linux/smp.h>
41 #include <linux/threads.h>
42 #include <linux/timer.h>
43 #include <linux/rcupdate.h>
44 #include <linux/cpu.h>
45 #include <linux/cpuset.h>
46 #include <linux/percpu.h>
47 #include <linux/kthread.h>
48 #include <linux/seq_file.h>
49 #include <linux/syscalls.h>
50 #include <linux/times.h>
51 #include <linux/acct.h>
52 #include <linux/kprobes.h>
53 #include <asm/tlb.h>
54
55 #include <asm/unistd.h>
56
57 /*
58  * Convert user-nice values [ -20 ... 0 ... 19 ]
59  * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
60  * and back.
61  */
62 #define NICE_TO_PRIO(nice)      (MAX_RT_PRIO + (nice) + 20)
63 #define PRIO_TO_NICE(prio)      ((prio) - MAX_RT_PRIO - 20)
64 #define TASK_NICE(p)            PRIO_TO_NICE((p)->static_prio)
65
66 /*
67  * 'User priority' is the nice value converted to something we
68  * can work with better when scaling various scheduler parameters,
69  * it's a [ 0 ... 39 ] range.
70  */
71 #define USER_PRIO(p)            ((p)-MAX_RT_PRIO)
72 #define TASK_USER_PRIO(p)       USER_PRIO((p)->static_prio)
73 #define MAX_USER_PRIO           (USER_PRIO(MAX_PRIO))
74
75 /*
76  * Some helpers for converting nanosecond timing to jiffy resolution
77  */
78 #define NS_TO_JIFFIES(TIME)     ((TIME) / (1000000000 / HZ))
79 #define JIFFIES_TO_NS(TIME)     ((TIME) * (1000000000 / HZ))
80
81 /*
82  * These are the 'tuning knobs' of the scheduler:
83  *
84  * Minimum timeslice is 5 msecs (or 1 jiffy, whichever is larger),
85  * default timeslice is 100 msecs, maximum timeslice is 800 msecs.
86  * Timeslices get refilled after they expire.
87  */
88 #define MIN_TIMESLICE           max(5 * HZ / 1000, 1)
89 #define DEF_TIMESLICE           (100 * HZ / 1000)
90 #define ON_RUNQUEUE_WEIGHT       30
91 #define CHILD_PENALTY            95
92 #define PARENT_PENALTY          100
93 #define EXIT_WEIGHT               3
94 #define PRIO_BONUS_RATIO         25
95 #define MAX_BONUS               (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100)
96 #define INTERACTIVE_DELTA         2
97 #define MAX_SLEEP_AVG           (DEF_TIMESLICE * MAX_BONUS)
98 #define STARVATION_LIMIT        (MAX_SLEEP_AVG)
99 #define NS_MAX_SLEEP_AVG        (JIFFIES_TO_NS(MAX_SLEEP_AVG))
100
101 /*
102  * If a task is 'interactive' then we reinsert it in the active
103  * array after it has expired its current timeslice. (it will not
104  * continue to run immediately, it will still roundrobin with
105  * other interactive tasks.)
106  *
107  * This part scales the interactivity limit depending on niceness.
108  *
109  * We scale it linearly, offset by the INTERACTIVE_DELTA delta.
110  * Here are a few examples of different nice levels:
111  *
112  *  TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0]
113  *  TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0]
114  *  TASK_INTERACTIVE(  0): [1,1,1,1,0,0,0,0,0,0,0]
115  *  TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0]
116  *  TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0]
117  *
118  * (the X axis represents the possible -5 ... 0 ... +5 dynamic
119  *  priority range a task can explore, a value of '1' means the
120  *  task is rated interactive.)
121  *
122  * Ie. nice +19 tasks can never get 'interactive' enough to be
123  * reinserted into the active array. And only heavily CPU-hog nice -20
124  * tasks will be expired. Default nice 0 tasks are somewhere between,
125  * it takes some effort for them to get interactive, but it's not
126  * too hard.
127  */
128
129 #define CURRENT_BONUS(p) \
130         (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \
131                 MAX_SLEEP_AVG)
132
133 #define GRANULARITY     (10 * HZ / 1000 ? : 1)
134
135 #ifdef CONFIG_SMP
136 #define TIMESLICE_GRANULARITY(p)        (GRANULARITY * \
137                 (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \
138                         num_online_cpus())
139 #else
140 #define TIMESLICE_GRANULARITY(p)        (GRANULARITY * \
141                 (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)))
142 #endif
143
144 #define SCALE(v1,v1_max,v2_max) \
145         (v1) * (v2_max) / (v1_max)
146
147 #define DELTA(p) \
148         (SCALE(TASK_NICE(p) + 20, 40, MAX_BONUS) - 20 * MAX_BONUS / 40 + \
149                 INTERACTIVE_DELTA)
150
151 #define TASK_INTERACTIVE(p) \
152         ((p)->prio <= (p)->static_prio - DELTA(p))
153
154 #define INTERACTIVE_SLEEP(p) \
155         (JIFFIES_TO_NS(MAX_SLEEP_AVG * \
156                 (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1))
157
158 #define TASK_PREEMPTS_CURR(p, rq) \
159         ((p)->prio < (rq)->curr->prio)
160
161 /*
162  * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ]
163  * to time slice values: [800ms ... 100ms ... 5ms]
164  *
165  * The higher a thread's priority, the bigger timeslices
166  * it gets during one round of execution. But even the lowest
167  * priority thread gets MIN_TIMESLICE worth of execution time.
168  */
169
170 #define SCALE_PRIO(x, prio) \
171         max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO/2), MIN_TIMESLICE)
172
173 static unsigned int task_timeslice(task_t *p)
174 {
175         if (p->static_prio < NICE_TO_PRIO(0))
176                 return SCALE_PRIO(DEF_TIMESLICE*4, p->static_prio);
177         else
178                 return SCALE_PRIO(DEF_TIMESLICE, p->static_prio);
179 }
180 #define task_hot(p, now, sd) ((long long) ((now) - (p)->last_ran)       \
181                                 < (long long) (sd)->cache_hot_time)
182
183 /*
184  * These are the runqueue data structures:
185  */
186
187 #define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
188
189 typedef struct runqueue runqueue_t;
190
191 struct prio_array {
192         unsigned int nr_active;
193         unsigned long bitmap[BITMAP_SIZE];
194         struct list_head queue[MAX_PRIO];
195 };
196
197 /*
198  * This is the main, per-CPU runqueue data structure.
199  *
200  * Locking rule: those places that want to lock multiple runqueues
201  * (such as the load balancing or the thread migration code), lock
202  * acquire operations must be ordered by ascending &runqueue.
203  */
204 struct runqueue {
205         spinlock_t lock;
206
207         /*
208          * nr_running and cpu_load should be in the same cacheline because
209          * remote CPUs use both these fields when doing load calculation.
210          */
211         unsigned long nr_running;
212 #ifdef CONFIG_SMP
213         unsigned long cpu_load[3];
214 #endif
215         unsigned long long nr_switches;
216
217         /*
218          * This is part of a global counter where only the total sum
219          * over all CPUs matters. A task can increase this counter on
220          * one CPU and if it got migrated afterwards it may decrease
221          * it on another CPU. Always updated under the runqueue lock:
222          */
223         unsigned long nr_uninterruptible;
224
225         unsigned long expired_timestamp;
226         unsigned long long timestamp_last_tick;
227         task_t *curr, *idle;
228         struct mm_struct *prev_mm;
229         prio_array_t *active, *expired, arrays[2];
230         int best_expired_prio;
231         atomic_t nr_iowait;
232
233 #ifdef CONFIG_SMP
234         struct sched_domain *sd;
235
236         /* For active balancing */
237         int active_balance;
238         int push_cpu;
239
240         task_t *migration_thread;
241         struct list_head migration_queue;
242         int cpu;
243 #endif
244
245 #ifdef CONFIG_SCHEDSTATS
246         /* latency stats */
247         struct sched_info rq_sched_info;
248
249         /* sys_sched_yield() stats */
250         unsigned long yld_exp_empty;
251         unsigned long yld_act_empty;
252         unsigned long yld_both_empty;
253         unsigned long yld_cnt;
254
255         /* schedule() stats */
256         unsigned long sched_switch;
257         unsigned long sched_cnt;
258         unsigned long sched_goidle;
259
260         /* try_to_wake_up() stats */
261         unsigned long ttwu_cnt;
262         unsigned long ttwu_local;
263 #endif
264 };
265
266 static DEFINE_PER_CPU(struct runqueue, runqueues);
267
268 /*
269  * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
270  * See detach_destroy_domains: synchronize_sched for details.
271  *
272  * The domain tree of any CPU may only be accessed from within
273  * preempt-disabled sections.
274  */
275 #define for_each_domain(cpu, domain) \
276 for (domain = rcu_dereference(cpu_rq(cpu)->sd); domain; domain = domain->parent)
277
278 #define cpu_rq(cpu)             (&per_cpu(runqueues, (cpu)))
279 #define this_rq()               (&__get_cpu_var(runqueues))
280 #define task_rq(p)              cpu_rq(task_cpu(p))
281 #define cpu_curr(cpu)           (cpu_rq(cpu)->curr)
282
283 #ifndef prepare_arch_switch
284 # define prepare_arch_switch(next)      do { } while (0)
285 #endif
286 #ifndef finish_arch_switch
287 # define finish_arch_switch(prev)       do { } while (0)
288 #endif
289
290 #ifndef __ARCH_WANT_UNLOCKED_CTXSW
291 static inline int task_running(runqueue_t *rq, task_t *p)
292 {
293         return rq->curr == p;
294 }
295
296 static inline void prepare_lock_switch(runqueue_t *rq, task_t *next)
297 {
298 }
299
300 static inline void finish_lock_switch(runqueue_t *rq, task_t *prev)
301 {
302 #ifdef CONFIG_DEBUG_SPINLOCK
303         /* this is a valid case when another task releases the spinlock */
304         rq->lock.owner = current;
305 #endif
306         spin_unlock_irq(&rq->lock);
307 }
308
309 #else /* __ARCH_WANT_UNLOCKED_CTXSW */
310 static inline int task_running(runqueue_t *rq, task_t *p)
311 {
312 #ifdef CONFIG_SMP
313         return p->oncpu;
314 #else
315         return rq->curr == p;
316 #endif
317 }
318
319 static inline void prepare_lock_switch(runqueue_t *rq, task_t *next)
320 {
321 #ifdef CONFIG_SMP
322         /*
323          * We can optimise this out completely for !SMP, because the
324          * SMP rebalancing from interrupt is the only thing that cares
325          * here.
326          */
327         next->oncpu = 1;
328 #endif
329 #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
330         spin_unlock_irq(&rq->lock);
331 #else
332         spin_unlock(&rq->lock);
333 #endif
334 }
335
336 static inline void finish_lock_switch(runqueue_t *rq, task_t *prev)
337 {
338 #ifdef CONFIG_SMP
339         /*
340          * After ->oncpu is cleared, the task can be moved to a different CPU.
341          * We must ensure this doesn't happen until the switch is completely
342          * finished.
343          */
344         smp_wmb();
345         prev->oncpu = 0;
346 #endif
347 #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
348         local_irq_enable();
349 #endif
350 }
351 #endif /* __ARCH_WANT_UNLOCKED_CTXSW */
352
353 /*
354  * task_rq_lock - lock the runqueue a given task resides on and disable
355  * interrupts.  Note the ordering: we can safely lookup the task_rq without
356  * explicitly disabling preemption.
357  */
358 static inline runqueue_t *task_rq_lock(task_t *p, unsigned long *flags)
359         __acquires(rq->lock)
360 {
361         struct runqueue *rq;
362
363 repeat_lock_task:
364         local_irq_save(*flags);
365         rq = task_rq(p);
366         spin_lock(&rq->lock);
367         if (unlikely(rq != task_rq(p))) {
368                 spin_unlock_irqrestore(&rq->lock, *flags);
369                 goto repeat_lock_task;
370         }
371         return rq;
372 }
373
374 static inline void task_rq_unlock(runqueue_t *rq, unsigned long *flags)
375         __releases(rq->lock)
376 {
377         spin_unlock_irqrestore(&rq->lock, *flags);
378 }
379
380 #ifdef CONFIG_SCHEDSTATS
381 /*
382  * bump this up when changing the output format or the meaning of an existing
383  * format, so that tools can adapt (or abort)
384  */
385 #define SCHEDSTAT_VERSION 12
386
387 static int show_schedstat(struct seq_file *seq, void *v)
388 {
389         int cpu;
390
391         seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION);
392         seq_printf(seq, "timestamp %lu\n", jiffies);
393         for_each_online_cpu(cpu) {
394                 runqueue_t *rq = cpu_rq(cpu);
395 #ifdef CONFIG_SMP
396                 struct sched_domain *sd;
397                 int dcnt = 0;
398 #endif
399
400                 /* runqueue-specific stats */
401                 seq_printf(seq,
402                     "cpu%d %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu",
403                     cpu, rq->yld_both_empty,
404                     rq->yld_act_empty, rq->yld_exp_empty, rq->yld_cnt,
405                     rq->sched_switch, rq->sched_cnt, rq->sched_goidle,
406                     rq->ttwu_cnt, rq->ttwu_local,
407                     rq->rq_sched_info.cpu_time,
408                     rq->rq_sched_info.run_delay, rq->rq_sched_info.pcnt);
409
410                 seq_printf(seq, "\n");
411
412 #ifdef CONFIG_SMP
413                 /* domain-specific stats */
414                 preempt_disable();
415                 for_each_domain(cpu, sd) {
416                         enum idle_type itype;
417                         char mask_str[NR_CPUS];
418
419                         cpumask_scnprintf(mask_str, NR_CPUS, sd->span);
420                         seq_printf(seq, "domain%d %s", dcnt++, mask_str);
421                         for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES;
422                                         itype++) {
423                                 seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu",
424                                     sd->lb_cnt[itype],
425                                     sd->lb_balanced[itype],
426                                     sd->lb_failed[itype],
427                                     sd->lb_imbalance[itype],
428                                     sd->lb_gained[itype],
429                                     sd->lb_hot_gained[itype],
430                                     sd->lb_nobusyq[itype],
431                                     sd->lb_nobusyg[itype]);
432                         }
433                         seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n",
434                             sd->alb_cnt, sd->alb_failed, sd->alb_pushed,
435                             sd->sbe_cnt, sd->sbe_balanced, sd->sbe_pushed,
436                             sd->sbf_cnt, sd->sbf_balanced, sd->sbf_pushed,
437                             sd->ttwu_wake_remote, sd->ttwu_move_affine, sd->ttwu_move_balance);
438                 }
439                 preempt_enable();
440 #endif
441         }
442         return 0;
443 }
444
445 static int schedstat_open(struct inode *inode, struct file *file)
446 {
447         unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32);
448         char *buf = kmalloc(size, GFP_KERNEL);
449         struct seq_file *m;
450         int res;
451
452         if (!buf)
453                 return -ENOMEM;
454         res = single_open(file, show_schedstat, NULL);
455         if (!res) {
456                 m = file->private_data;
457                 m->buf = buf;
458                 m->size = size;
459         } else
460                 kfree(buf);
461         return res;
462 }
463
464 struct file_operations proc_schedstat_operations = {
465         .open    = schedstat_open,
466         .read    = seq_read,
467         .llseek  = seq_lseek,
468         .release = single_release,
469 };
470
471 # define schedstat_inc(rq, field)       do { (rq)->field++; } while (0)
472 # define schedstat_add(rq, field, amt)  do { (rq)->field += (amt); } while (0)
473 #else /* !CONFIG_SCHEDSTATS */
474 # define schedstat_inc(rq, field)       do { } while (0)
475 # define schedstat_add(rq, field, amt)  do { } while (0)
476 #endif
477
478 /*
479  * rq_lock - lock a given runqueue and disable interrupts.
480  */
481 static inline runqueue_t *this_rq_lock(void)
482         __acquires(rq->lock)
483 {
484         runqueue_t *rq;
485
486         local_irq_disable();
487         rq = this_rq();
488         spin_lock(&rq->lock);
489
490         return rq;
491 }
492
493 #ifdef CONFIG_SCHEDSTATS
494 /*
495  * Called when a process is dequeued from the active array and given
496  * the cpu.  We should note that with the exception of interactive
497  * tasks, the expired queue will become the active queue after the active
498  * queue is empty, without explicitly dequeuing and requeuing tasks in the
499  * expired queue.  (Interactive tasks may be requeued directly to the
500  * active queue, thus delaying tasks in the expired queue from running;
501  * see scheduler_tick()).
502  *
503  * This function is only called from sched_info_arrive(), rather than
504  * dequeue_task(). Even though a task may be queued and dequeued multiple
505  * times as it is shuffled about, we're really interested in knowing how
506  * long it was from the *first* time it was queued to the time that it
507  * finally hit a cpu.
508  */
509 static inline void sched_info_dequeued(task_t *t)
510 {
511         t->sched_info.last_queued = 0;
512 }
513
514 /*
515  * Called when a task finally hits the cpu.  We can now calculate how
516  * long it was waiting to run.  We also note when it began so that we
517  * can keep stats on how long its timeslice is.
518  */
519 static void sched_info_arrive(task_t *t)
520 {
521         unsigned long now = jiffies, diff = 0;
522         struct runqueue *rq = task_rq(t);
523
524         if (t->sched_info.last_queued)
525                 diff = now - t->sched_info.last_queued;
526         sched_info_dequeued(t);
527         t->sched_info.run_delay += diff;
528         t->sched_info.last_arrival = now;
529         t->sched_info.pcnt++;
530
531         if (!rq)
532                 return;
533
534         rq->rq_sched_info.run_delay += diff;
535         rq->rq_sched_info.pcnt++;
536 }
537
538 /*
539  * Called when a process is queued into either the active or expired
540  * array.  The time is noted and later used to determine how long we
541  * had to wait for us to reach the cpu.  Since the expired queue will
542  * become the active queue after active queue is empty, without dequeuing
543  * and requeuing any tasks, we are interested in queuing to either. It
544  * is unusual but not impossible for tasks to be dequeued and immediately
545  * requeued in the same or another array: this can happen in sched_yield(),
546  * set_user_nice(), and even load_balance() as it moves tasks from runqueue
547  * to runqueue.
548  *
549  * This function is only called from enqueue_task(), but also only updates
550  * the timestamp if it is already not set.  It's assumed that
551  * sched_info_dequeued() will clear that stamp when appropriate.
552  */
553 static inline void sched_info_queued(task_t *t)
554 {
555         if (!t->sched_info.last_queued)
556                 t->sched_info.last_queued = jiffies;
557 }
558
559 /*
560  * Called when a process ceases being the active-running process, either
561  * voluntarily or involuntarily.  Now we can calculate how long we ran.
562  */
563 static inline void sched_info_depart(task_t *t)
564 {
565         struct runqueue *rq = task_rq(t);
566         unsigned long diff = jiffies - t->sched_info.last_arrival;
567
568         t->sched_info.cpu_time += diff;
569
570         if (rq)
571                 rq->rq_sched_info.cpu_time += diff;
572 }
573
574 /*
575  * Called when tasks are switched involuntarily due, typically, to expiring
576  * their time slice.  (This may also be called when switching to or from
577  * the idle task.)  We are only called when prev != next.
578  */
579 static inline void sched_info_switch(task_t *prev, task_t *next)
580 {
581         struct runqueue *rq = task_rq(prev);
582
583         /*
584          * prev now departs the cpu.  It's not interesting to record
585          * stats about how efficient we were at scheduling the idle
586          * process, however.
587          */
588         if (prev != rq->idle)
589                 sched_info_depart(prev);
590
591         if (next != rq->idle)
592                 sched_info_arrive(next);
593 }
594 #else
595 #define sched_info_queued(t)            do { } while (0)
596 #define sched_info_switch(t, next)      do { } while (0)
597 #endif /* CONFIG_SCHEDSTATS */
598
599 /*
600  * Adding/removing a task to/from a priority array:
601  */
602 static void dequeue_task(struct task_struct *p, prio_array_t *array)
603 {
604         array->nr_active--;
605         list_del(&p->run_list);
606         if (list_empty(array->queue + p->prio))
607                 __clear_bit(p->prio, array->bitmap);
608 }
609
610 static void enqueue_task(struct task_struct *p, prio_array_t *array)
611 {
612         sched_info_queued(p);
613         list_add_tail(&p->run_list, array->queue + p->prio);
614         __set_bit(p->prio, array->bitmap);
615         array->nr_active++;
616         p->array = array;
617 }
618
619 /*
620  * Put task to the end of the run list without the overhead of dequeue
621  * followed by enqueue.
622  */
623 static void requeue_task(struct task_struct *p, prio_array_t *array)
624 {
625         list_move_tail(&p->run_list, array->queue + p->prio);
626 }
627
628 static inline void enqueue_task_head(struct task_struct *p, prio_array_t *array)
629 {
630         list_add(&p->run_list, array->queue + p->prio);
631         __set_bit(p->prio, array->bitmap);
632         array->nr_active++;
633         p->array = array;
634 }
635
636 /*
637  * effective_prio - return the priority that is based on the static
638  * priority but is modified by bonuses/penalties.
639  *
640  * We scale the actual sleep average [0 .... MAX_SLEEP_AVG]
641  * into the -5 ... 0 ... +5 bonus/penalty range.
642  *
643  * We use 25% of the full 0...39 priority range so that:
644  *
645  * 1) nice +19 interactive tasks do not preempt nice 0 CPU hogs.
646  * 2) nice -20 CPU hogs do not get preempted by nice 0 tasks.
647  *
648  * Both properties are important to certain workloads.
649  */
650 static int effective_prio(task_t *p)
651 {
652         int bonus, prio;
653
654         if (rt_task(p))
655                 return p->prio;
656
657         bonus = CURRENT_BONUS(p) - MAX_BONUS / 2;
658
659         prio = p->static_prio - bonus;
660         if (prio < MAX_RT_PRIO)
661                 prio = MAX_RT_PRIO;
662         if (prio > MAX_PRIO-1)
663                 prio = MAX_PRIO-1;
664         return prio;
665 }
666
667 /*
668  * __activate_task - move a task to the runqueue.
669  */
670 static void __activate_task(task_t *p, runqueue_t *rq)
671 {
672         prio_array_t *target = rq->active;
673
674         if (batch_task(p))
675                 target = rq->expired;
676         enqueue_task(p, target);
677         rq->nr_running++;
678 }
679
680 /*
681  * __activate_idle_task - move idle task to the _front_ of runqueue.
682  */
683 static inline void __activate_idle_task(task_t *p, runqueue_t *rq)
684 {
685         enqueue_task_head(p, rq->active);
686         rq->nr_running++;
687 }
688
689 static int recalc_task_prio(task_t *p, unsigned long long now)
690 {
691         /* Caller must always ensure 'now >= p->timestamp' */
692         unsigned long long __sleep_time = now - p->timestamp;
693         unsigned long sleep_time;
694
695         if (batch_task(p))
696                 sleep_time = 0;
697         else {
698                 if (__sleep_time > NS_MAX_SLEEP_AVG)
699                         sleep_time = NS_MAX_SLEEP_AVG;
700                 else
701                         sleep_time = (unsigned long)__sleep_time;
702         }
703
704         if (likely(sleep_time > 0)) {
705                 /*
706                  * User tasks that sleep a long time are categorised as
707                  * idle. They will only have their sleep_avg increased to a
708                  * level that makes them just interactive priority to stay
709                  * active yet prevent them suddenly becoming cpu hogs and
710                  * starving other processes.
711                  */
712                 if (p->mm && sleep_time > INTERACTIVE_SLEEP(p)) {
713                                 unsigned long ceiling;
714
715                                 ceiling = JIFFIES_TO_NS(MAX_SLEEP_AVG -
716                                         DEF_TIMESLICE);
717                                 if (p->sleep_avg < ceiling)
718                                         p->sleep_avg = ceiling;
719                 } else {
720                         /*
721                          * Tasks waking from uninterruptible sleep are
722                          * limited in their sleep_avg rise as they
723                          * are likely to be waiting on I/O
724                          */
725                         if (p->sleep_type == SLEEP_NONINTERACTIVE && p->mm) {
726                                 if (p->sleep_avg >= INTERACTIVE_SLEEP(p))
727                                         sleep_time = 0;
728                                 else if (p->sleep_avg + sleep_time >=
729                                                 INTERACTIVE_SLEEP(p)) {
730                                         p->sleep_avg = INTERACTIVE_SLEEP(p);
731                                         sleep_time = 0;
732                                 }
733                         }
734
735                         /*
736                          * This code gives a bonus to interactive tasks.
737                          *
738                          * The boost works by updating the 'average sleep time'
739                          * value here, based on ->timestamp. The more time a
740                          * task spends sleeping, the higher the average gets -
741                          * and the higher the priority boost gets as well.
742                          */
743                         p->sleep_avg += sleep_time;
744
745                         if (p->sleep_avg > NS_MAX_SLEEP_AVG)
746                                 p->sleep_avg = NS_MAX_SLEEP_AVG;
747                 }
748         }
749
750         return effective_prio(p);
751 }
752
753 /*
754  * activate_task - move a task to the runqueue and do priority recalculation
755  *
756  * Update all the scheduling statistics stuff. (sleep average
757  * calculation, priority modifiers, etc.)
758  */
759 static void activate_task(task_t *p, runqueue_t *rq, int local)
760 {
761         unsigned long long now;
762
763         now = sched_clock();
764 #ifdef CONFIG_SMP
765         if (!local) {
766                 /* Compensate for drifting sched_clock */
767                 runqueue_t *this_rq = this_rq();
768                 now = (now - this_rq->timestamp_last_tick)
769                         + rq->timestamp_last_tick;
770         }
771 #endif
772
773         if (!rt_task(p))
774                 p->prio = recalc_task_prio(p, now);
775
776         /*
777          * This checks to make sure it's not an uninterruptible task
778          * that is now waking up.
779          */
780         if (p->sleep_type == SLEEP_NORMAL) {
781                 /*
782                  * Tasks which were woken up by interrupts (ie. hw events)
783                  * are most likely of interactive nature. So we give them
784                  * the credit of extending their sleep time to the period
785                  * of time they spend on the runqueue, waiting for execution
786                  * on a CPU, first time around:
787                  */
788                 if (in_interrupt())
789                         p->sleep_type = SLEEP_INTERRUPTED;
790                 else {
791                         /*
792                          * Normal first-time wakeups get a credit too for
793                          * on-runqueue time, but it will be weighted down:
794                          */
795                         p->sleep_type = SLEEP_INTERACTIVE;
796                 }
797         }
798         p->timestamp = now;
799
800         __activate_task(p, rq);
801 }
802
803 /*
804  * deactivate_task - remove a task from the runqueue.
805  */
806 static void deactivate_task(struct task_struct *p, runqueue_t *rq)
807 {
808         rq->nr_running--;
809         dequeue_task(p, p->array);
810         p->array = NULL;
811 }
812
813 /*
814  * resched_task - mark a task 'to be rescheduled now'.
815  *
816  * On UP this means the setting of the need_resched flag, on SMP it
817  * might also involve a cross-CPU call to trigger the scheduler on
818  * the target CPU.
819  */
820 #ifdef CONFIG_SMP
821
822 #ifndef tsk_is_polling
823 #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
824 #endif
825
826 static void resched_task(task_t *p)
827 {
828         int cpu;
829
830         assert_spin_locked(&task_rq(p)->lock);
831
832         if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
833                 return;
834
835         set_tsk_thread_flag(p, TIF_NEED_RESCHED);
836
837         cpu = task_cpu(p);
838         if (cpu == smp_processor_id())
839                 return;
840
841         /* NEED_RESCHED must be visible before we test polling */
842         smp_mb();
843         if (!tsk_is_polling(p))
844                 smp_send_reschedule(cpu);
845 }
846 #else
847 static inline void resched_task(task_t *p)
848 {
849         assert_spin_locked(&task_rq(p)->lock);
850         set_tsk_need_resched(p);
851 }
852 #endif
853
854 /**
855  * task_curr - is this task currently executing on a CPU?
856  * @p: the task in question.
857  */
858 inline int task_curr(const task_t *p)
859 {
860         return cpu_curr(task_cpu(p)) == p;
861 }
862
863 #ifdef CONFIG_SMP
864 typedef struct {
865         struct list_head list;
866
867         task_t *task;
868         int dest_cpu;
869
870         struct completion done;
871 } migration_req_t;
872
873 /*
874  * The task's runqueue lock must be held.
875  * Returns true if you have to wait for migration thread.
876  */
877 static int migrate_task(task_t *p, int dest_cpu, migration_req_t *req)
878 {
879         runqueue_t *rq = task_rq(p);
880
881         /*
882          * If the task is not on a runqueue (and not running), then
883          * it is sufficient to simply update the task's cpu field.
884          */
885         if (!p->array && !task_running(rq, p)) {
886                 set_task_cpu(p, dest_cpu);
887                 return 0;
888         }
889
890         init_completion(&req->done);
891         req->task = p;
892         req->dest_cpu = dest_cpu;
893         list_add(&req->list, &rq->migration_queue);
894         return 1;
895 }
896
897 /*
898  * wait_task_inactive - wait for a thread to unschedule.
899  *
900  * The caller must ensure that the task *will* unschedule sometime soon,
901  * else this function might spin for a *long* time. This function can't
902  * be called with interrupts off, or it may introduce deadlock with
903  * smp_call_function() if an IPI is sent by the same process we are
904  * waiting to become inactive.
905  */
906 void wait_task_inactive(task_t *p)
907 {
908         unsigned long flags;
909         runqueue_t *rq;
910         int preempted;
911
912 repeat:
913         rq = task_rq_lock(p, &flags);
914         /* Must be off runqueue entirely, not preempted. */
915         if (unlikely(p->array || task_running(rq, p))) {
916                 /* If it's preempted, we yield.  It could be a while. */
917                 preempted = !task_running(rq, p);
918                 task_rq_unlock(rq, &flags);
919                 cpu_relax();
920                 if (preempted)
921                         yield();
922                 goto repeat;
923         }
924         task_rq_unlock(rq, &flags);
925 }
926
927 /***
928  * kick_process - kick a running thread to enter/exit the kernel
929  * @p: the to-be-kicked thread
930  *
931  * Cause a process which is running on another CPU to enter
932  * kernel-mode, without any delay. (to get signals handled.)
933  *
934  * NOTE: this function doesnt have to take the runqueue lock,
935  * because all it wants to ensure is that the remote task enters
936  * the kernel. If the IPI races and the task has been migrated
937  * to another CPU then no harm is done and the purpose has been
938  * achieved as well.
939  */
940 void kick_process(task_t *p)
941 {
942         int cpu;
943
944         preempt_disable();
945         cpu = task_cpu(p);
946         if ((cpu != smp_processor_id()) && task_curr(p))
947                 smp_send_reschedule(cpu);
948         preempt_enable();
949 }
950
951 /*
952  * Return a low guess at the load of a migration-source cpu.
953  *
954  * We want to under-estimate the load of migration sources, to
955  * balance conservatively.
956  */
957 static inline unsigned long source_load(int cpu, int type)
958 {
959         runqueue_t *rq = cpu_rq(cpu);
960         unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
961         if (type == 0)
962                 return load_now;
963
964         return min(rq->cpu_load[type-1], load_now);
965 }
966
967 /*
968  * Return a high guess at the load of a migration-target cpu
969  */
970 static inline unsigned long target_load(int cpu, int type)
971 {
972         runqueue_t *rq = cpu_rq(cpu);
973         unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE;
974         if (type == 0)
975                 return load_now;
976
977         return max(rq->cpu_load[type-1], load_now);
978 }
979
980 /*
981  * find_idlest_group finds and returns the least busy CPU group within the
982  * domain.
983  */
984 static struct sched_group *
985 find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
986 {
987         struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
988         unsigned long min_load = ULONG_MAX, this_load = 0;
989         int load_idx = sd->forkexec_idx;
990         int imbalance = 100 + (sd->imbalance_pct-100)/2;
991
992         do {
993                 unsigned long load, avg_load;
994                 int local_group;
995                 int i;
996
997                 /* Skip over this group if it has no CPUs allowed */
998                 if (!cpus_intersects(group->cpumask, p->cpus_allowed))
999                         goto nextgroup;
1000
1001                 local_group = cpu_isset(this_cpu, group->cpumask);
1002
1003                 /* Tally up the load of all CPUs in the group */
1004                 avg_load = 0;
1005
1006                 for_each_cpu_mask(i, group->cpumask) {
1007                         /* Bias balancing toward cpus of our domain */
1008                         if (local_group)
1009                                 load = source_load(i, load_idx);
1010                         else
1011                                 load = target_load(i, load_idx);
1012
1013                         avg_load += load;
1014                 }
1015
1016                 /* Adjust by relative CPU power of the group */
1017                 avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
1018
1019                 if (local_group) {
1020                         this_load = avg_load;
1021                         this = group;
1022                 } else if (avg_load < min_load) {
1023                         min_load = avg_load;
1024                         idlest = group;
1025                 }
1026 nextgroup:
1027                 group = group->next;
1028         } while (group != sd->groups);
1029
1030         if (!idlest || 100*this_load < imbalance*min_load)
1031                 return NULL;
1032         return idlest;
1033 }
1034
1035 /*
1036  * find_idlest_queue - find the idlest runqueue among the cpus in group.
1037  */
1038 static int
1039 find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
1040 {
1041         cpumask_t tmp;
1042         unsigned long load, min_load = ULONG_MAX;
1043         int idlest = -1;
1044         int i;
1045
1046         /* Traverse only the allowed CPUs */
1047         cpus_and(tmp, group->cpumask, p->cpus_allowed);
1048
1049         for_each_cpu_mask(i, tmp) {
1050                 load = source_load(i, 0);
1051
1052                 if (load < min_load || (load == min_load && i == this_cpu)) {
1053                         min_load = load;
1054                         idlest = i;
1055                 }
1056         }
1057
1058         return idlest;
1059 }
1060
1061 /*
1062  * sched_balance_self: balance the current task (running on cpu) in domains
1063  * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
1064  * SD_BALANCE_EXEC.
1065  *
1066  * Balance, ie. select the least loaded group.
1067  *
1068  * Returns the target CPU number, or the same CPU if no balancing is needed.
1069  *
1070  * preempt must be disabled.
1071  */
1072 static int sched_balance_self(int cpu, int flag)
1073 {
1074         struct task_struct *t = current;
1075         struct sched_domain *tmp, *sd = NULL;
1076
1077         for_each_domain(cpu, tmp)
1078                 if (tmp->flags & flag)
1079                         sd = tmp;
1080
1081         while (sd) {
1082                 cpumask_t span;
1083                 struct sched_group *group;
1084                 int new_cpu;
1085                 int weight;
1086
1087                 span = sd->span;
1088                 group = find_idlest_group(sd, t, cpu);
1089                 if (!group)
1090                         goto nextlevel;
1091
1092                 new_cpu = find_idlest_cpu(group, t, cpu);
1093                 if (new_cpu == -1 || new_cpu == cpu)
1094                         goto nextlevel;
1095
1096                 /* Now try balancing at a lower domain level */
1097                 cpu = new_cpu;
1098 nextlevel:
1099                 sd = NULL;
1100                 weight = cpus_weight(span);
1101                 for_each_domain(cpu, tmp) {
1102                         if (weight <= cpus_weight(tmp->span))
1103                                 break;
1104                         if (tmp->flags & flag)
1105                                 sd = tmp;
1106                 }
1107                 /* while loop will break here if sd == NULL */
1108         }
1109
1110         return cpu;
1111 }
1112
1113 #endif /* CONFIG_SMP */
1114
1115 /*
1116  * wake_idle() will wake a task on an idle cpu if task->cpu is
1117  * not idle and an idle cpu is available.  The span of cpus to
1118  * search starts with cpus closest then further out as needed,
1119  * so we always favor a closer, idle cpu.
1120  *
1121  * Returns the CPU we should wake onto.
1122  */
1123 #if defined(ARCH_HAS_SCHED_WAKE_IDLE)
1124 static int wake_idle(int cpu, task_t *p)
1125 {
1126         cpumask_t tmp;
1127         struct sched_domain *sd;
1128         int i;
1129
1130         if (idle_cpu(cpu))
1131                 return cpu;
1132
1133         for_each_domain(cpu, sd) {
1134                 if (sd->flags & SD_WAKE_IDLE) {
1135                         cpus_and(tmp, sd->span, p->cpus_allowed);
1136                         for_each_cpu_mask(i, tmp) {
1137                                 if (idle_cpu(i))
1138                                         return i;
1139                         }
1140                 }
1141                 else
1142                         break;
1143         }
1144         return cpu;
1145 }
1146 #else
1147 static inline int wake_idle(int cpu, task_t *p)
1148 {
1149         return cpu;
1150 }
1151 #endif
1152
1153 /***
1154  * try_to_wake_up - wake up a thread
1155  * @p: the to-be-woken-up thread
1156  * @state: the mask of task states that can be woken
1157  * @sync: do a synchronous wakeup?
1158  *
1159  * Put it on the run-queue if it's not already there. The "current"
1160  * thread is always on the run-queue (except when the actual
1161  * re-schedule is in progress), and as such you're allowed to do
1162  * the simpler "current->state = TASK_RUNNING" to mark yourself
1163  * runnable without the overhead of this.
1164  *
1165  * returns failure only if the task is already active.
1166  */
1167 static int try_to_wake_up(task_t *p, unsigned int state, int sync)
1168 {
1169         int cpu, this_cpu, success = 0;
1170         unsigned long flags;
1171         long old_state;
1172         runqueue_t *rq;
1173 #ifdef CONFIG_SMP
1174         unsigned long load, this_load;
1175         struct sched_domain *sd, *this_sd = NULL;
1176         int new_cpu;
1177 #endif
1178
1179         rq = task_rq_lock(p, &flags);
1180         old_state = p->state;
1181         if (!(old_state & state))
1182                 goto out;
1183
1184         if (p->array)
1185                 goto out_running;
1186
1187         cpu = task_cpu(p);
1188         this_cpu = smp_processor_id();
1189
1190 #ifdef CONFIG_SMP
1191         if (unlikely(task_running(rq, p)))
1192                 goto out_activate;
1193
1194         new_cpu = cpu;
1195
1196         schedstat_inc(rq, ttwu_cnt);
1197         if (cpu == this_cpu) {
1198                 schedstat_inc(rq, ttwu_local);
1199                 goto out_set_cpu;
1200         }
1201
1202         for_each_domain(this_cpu, sd) {
1203                 if (cpu_isset(cpu, sd->span)) {
1204                         schedstat_inc(sd, ttwu_wake_remote);
1205                         this_sd = sd;
1206                         break;
1207                 }
1208         }
1209
1210         if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
1211                 goto out_set_cpu;
1212
1213         /*
1214          * Check for affine wakeup and passive balancing possibilities.
1215          */
1216         if (this_sd) {
1217                 int idx = this_sd->wake_idx;
1218                 unsigned int imbalance;
1219
1220                 imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
1221
1222                 load = source_load(cpu, idx);
1223                 this_load = target_load(this_cpu, idx);
1224
1225                 new_cpu = this_cpu; /* Wake to this CPU if we can */
1226
1227                 if (this_sd->flags & SD_WAKE_AFFINE) {
1228                         unsigned long tl = this_load;
1229                         /*
1230                          * If sync wakeup then subtract the (maximum possible)
1231                          * effect of the currently running task from the load
1232                          * of the current CPU:
1233                          */
1234                         if (sync)
1235                                 tl -= SCHED_LOAD_SCALE;
1236
1237                         if ((tl <= load &&
1238                                 tl + target_load(cpu, idx) <= SCHED_LOAD_SCALE) ||
1239                                 100*(tl + SCHED_LOAD_SCALE) <= imbalance*load) {
1240                                 /*
1241                                  * This domain has SD_WAKE_AFFINE and
1242                                  * p is cache cold in this domain, and
1243                                  * there is no bad imbalance.
1244                                  */
1245                                 schedstat_inc(this_sd, ttwu_move_affine);
1246                                 goto out_set_cpu;
1247                         }
1248                 }
1249
1250                 /*
1251                  * Start passive balancing when half the imbalance_pct
1252                  * limit is reached.
1253                  */
1254                 if (this_sd->flags & SD_WAKE_BALANCE) {
1255                         if (imbalance*this_load <= 100*load) {
1256                                 schedstat_inc(this_sd, ttwu_move_balance);
1257                                 goto out_set_cpu;
1258                         }
1259                 }
1260         }
1261
1262         new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */
1263 out_set_cpu:
1264         new_cpu = wake_idle(new_cpu, p);
1265         if (new_cpu != cpu) {
1266                 set_task_cpu(p, new_cpu);
1267                 task_rq_unlock(rq, &flags);
1268                 /* might preempt at this point */
1269                 rq = task_rq_lock(p, &flags);
1270                 old_state = p->state;
1271                 if (!(old_state & state))
1272                         goto out;
1273                 if (p->array)
1274                         goto out_running;
1275
1276                 this_cpu = smp_processor_id();
1277                 cpu = task_cpu(p);
1278         }
1279
1280 out_activate:
1281 #endif /* CONFIG_SMP */
1282         if (old_state == TASK_UNINTERRUPTIBLE) {
1283                 rq->nr_uninterruptible--;
1284                 /*
1285                  * Tasks on involuntary sleep don't earn
1286                  * sleep_avg beyond just interactive state.
1287                  */
1288                 p->sleep_type = SLEEP_NONINTERACTIVE;
1289         } else
1290
1291         /*
1292          * Tasks that have marked their sleep as noninteractive get
1293          * woken up with their sleep average not weighted in an
1294          * interactive way.
1295          */
1296                 if (old_state & TASK_NONINTERACTIVE)
1297                         p->sleep_type = SLEEP_NONINTERACTIVE;
1298
1299
1300         activate_task(p, rq, cpu == this_cpu);
1301         /*
1302          * Sync wakeups (i.e. those types of wakeups where the waker
1303          * has indicated that it will leave the CPU in short order)
1304          * don't trigger a preemption, if the woken up task will run on
1305          * this cpu. (in this case the 'I will reschedule' promise of
1306          * the waker guarantees that the freshly woken up task is going
1307          * to be considered on this CPU.)
1308          */
1309         if (!sync || cpu != this_cpu) {
1310                 if (TASK_PREEMPTS_CURR(p, rq))
1311                         resched_task(rq->curr);
1312         }
1313         success = 1;
1314
1315 out_running:
1316         p->state = TASK_RUNNING;
1317 out:
1318         task_rq_unlock(rq, &flags);
1319
1320         return success;
1321 }
1322
1323 int fastcall wake_up_process(task_t *p)
1324 {
1325         return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED |
1326                                  TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0);
1327 }
1328
1329 EXPORT_SYMBOL(wake_up_process);
1330
1331 int fastcall wake_up_state(task_t *p, unsigned int state)
1332 {
1333         return try_to_wake_up(p, state, 0);
1334 }
1335
1336 /*
1337  * Perform scheduler related setup for a newly forked process p.
1338  * p is forked by current.
1339  */
1340 void fastcall sched_fork(task_t *p, int clone_flags)
1341 {
1342         int cpu = get_cpu();
1343
1344 #ifdef CONFIG_SMP
1345         cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
1346 #endif
1347         set_task_cpu(p, cpu);
1348
1349         /*
1350          * We mark the process as running here, but have not actually
1351          * inserted it onto the runqueue yet. This guarantees that
1352          * nobody will actually run it, and a signal or other external
1353          * event cannot wake it up and insert it on the runqueue either.
1354          */
1355         p->state = TASK_RUNNING;
1356         INIT_LIST_HEAD(&p->run_list);
1357         p->array = NULL;
1358 #ifdef CONFIG_SCHEDSTATS
1359         memset(&p->sched_info, 0, sizeof(p->sched_info));
1360 #endif
1361 #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
1362         p->oncpu = 0;
1363 #endif
1364 #ifdef CONFIG_PREEMPT
1365         /* Want to start with kernel preemption disabled. */
1366         task_thread_info(p)->preempt_count = 1;
1367 #endif
1368         /*
1369          * Share the timeslice between parent and child, thus the
1370          * total amount of pending timeslices in the system doesn't change,
1371          * resulting in more scheduling fairness.
1372          */
1373         local_irq_disable();
1374         p->time_slice = (current->time_slice + 1) >> 1;
1375         /*
1376          * The remainder of the first timeslice might be recovered by
1377          * the parent if the child exits early enough.
1378          */
1379         p->first_time_slice = 1;
1380         current->time_slice >>= 1;
1381         p->timestamp = sched_clock();
1382         if (unlikely(!current->time_slice)) {
1383                 /*
1384                  * This case is rare, it happens when the parent has only
1385                  * a single jiffy left from its timeslice. Taking the
1386                  * runqueue lock is not a problem.
1387                  */
1388                 current->time_slice = 1;
1389                 scheduler_tick();
1390         }
1391         local_irq_enable();
1392         put_cpu();
1393 }
1394
1395 /*
1396  * wake_up_new_task - wake up a newly created task for the first time.
1397  *
1398  * This function will do some initial scheduler statistics housekeeping
1399  * that must be done for every newly created context, then puts the task
1400  * on the runqueue and wakes it.
1401  */
1402 void fastcall wake_up_new_task(task_t *p, unsigned long clone_flags)
1403 {
1404         unsigned long flags;
1405         int this_cpu, cpu;
1406         runqueue_t *rq, *this_rq;
1407
1408         rq = task_rq_lock(p, &flags);
1409         BUG_ON(p->state != TASK_RUNNING);
1410         this_cpu = smp_processor_id();
1411         cpu = task_cpu(p);
1412
1413         /*
1414          * We decrease the sleep average of forking parents
1415          * and children as well, to keep max-interactive tasks
1416          * from forking tasks that are max-interactive. The parent
1417          * (current) is done further down, under its lock.
1418          */
1419         p->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(p) *
1420                 CHILD_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS);
1421
1422         p->prio = effective_prio(p);
1423
1424         if (likely(cpu == this_cpu)) {
1425                 if (!(clone_flags & CLONE_VM)) {
1426                         /*
1427                          * The VM isn't cloned, so we're in a good position to
1428                          * do child-runs-first in anticipation of an exec. This
1429                          * usually avoids a lot of COW overhead.
1430                          */
1431                         if (unlikely(!current->array))
1432                                 __activate_task(p, rq);
1433                         else {
1434                                 p->prio = current->prio;
1435                                 list_add_tail(&p->run_list, &current->run_list);
1436                                 p->array = current->array;
1437                                 p->array->nr_active++;
1438                                 rq->nr_running++;
1439                         }
1440                         set_need_resched();
1441                 } else
1442                         /* Run child last */
1443                         __activate_task(p, rq);
1444                 /*
1445                  * We skip the following code due to cpu == this_cpu
1446                  *
1447                  *   task_rq_unlock(rq, &flags);
1448                  *   this_rq = task_rq_lock(current, &flags);
1449                  */
1450                 this_rq = rq;
1451         } else {
1452                 this_rq = cpu_rq(this_cpu);
1453
1454                 /*
1455                  * Not the local CPU - must adjust timestamp. This should
1456                  * get optimised away in the !CONFIG_SMP case.
1457                  */
1458                 p->timestamp = (p->timestamp - this_rq->timestamp_last_tick)
1459                                         + rq->timestamp_last_tick;
1460                 __activate_task(p, rq);
1461                 if (TASK_PREEMPTS_CURR(p, rq))
1462                         resched_task(rq->curr);
1463
1464                 /*
1465                  * Parent and child are on different CPUs, now get the
1466                  * parent runqueue to update the parent's ->sleep_avg:
1467                  */
1468                 task_rq_unlock(rq, &flags);
1469                 this_rq = task_rq_lock(current, &flags);
1470         }
1471         current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) *
1472                 PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS);
1473         task_rq_unlock(this_rq, &flags);
1474 }
1475
1476 /*
1477  * Potentially available exiting-child timeslices are
1478  * retrieved here - this way the parent does not get
1479  * penalized for creating too many threads.
1480  *
1481  * (this cannot be used to 'generate' timeslices
1482  * artificially, because any timeslice recovered here
1483  * was given away by the parent in the first place.)
1484  */
1485 void fastcall sched_exit(task_t *p)
1486 {
1487         unsigned long flags;
1488         runqueue_t *rq;
1489
1490         /*
1491          * If the child was a (relative-) CPU hog then decrease
1492          * the sleep_avg of the parent as well.
1493          */
1494         rq = task_rq_lock(p->parent, &flags);
1495         if (p->first_time_slice && task_cpu(p) == task_cpu(p->parent)) {
1496                 p->parent->time_slice += p->time_slice;
1497                 if (unlikely(p->parent->time_slice > task_timeslice(p)))
1498                         p->parent->time_slice = task_timeslice(p);
1499         }
1500         if (p->sleep_avg < p->parent->sleep_avg)
1501                 p->parent->sleep_avg = p->parent->sleep_avg /
1502                 (EXIT_WEIGHT + 1) * EXIT_WEIGHT + p->sleep_avg /
1503                 (EXIT_WEIGHT + 1);
1504         task_rq_unlock(rq, &flags);
1505 }
1506
1507 /**
1508  * prepare_task_switch - prepare to switch tasks
1509  * @rq: the runqueue preparing to switch
1510  * @next: the task we are going to switch to.
1511  *
1512  * This is called with the rq lock held and interrupts off. It must
1513  * be paired with a subsequent finish_task_switch after the context
1514  * switch.
1515  *
1516  * prepare_task_switch sets up locking and calls architecture specific
1517  * hooks.
1518  */
1519 static inline void prepare_task_switch(runqueue_t *rq, task_t *next)
1520 {
1521         prepare_lock_switch(rq, next);
1522         prepare_arch_switch(next);
1523 }
1524
1525 /**
1526  * finish_task_switch - clean up after a task-switch
1527  * @rq: runqueue associated with task-switch
1528  * @prev: the thread we just switched away from.
1529  *
1530  * finish_task_switch must be called after the context switch, paired
1531  * with a prepare_task_switch call before the context switch.
1532  * finish_task_switch will reconcile locking set up by prepare_task_switch,
1533  * and do any other architecture-specific cleanup actions.
1534  *
1535  * Note that we may have delayed dropping an mm in context_switch(). If
1536  * so, we finish that here outside of the runqueue lock.  (Doing it
1537  * with the lock held can cause deadlocks; see schedule() for
1538  * details.)
1539  */
1540 static inline void finish_task_switch(runqueue_t *rq, task_t *prev)
1541         __releases(rq->lock)
1542 {
1543         struct mm_struct *mm = rq->prev_mm;
1544         unsigned long prev_task_flags;
1545
1546         rq->prev_mm = NULL;
1547
1548         /*
1549          * A task struct has one reference for the use as "current".
1550          * If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and
1551          * calls schedule one last time. The schedule call will never return,
1552          * and the scheduled task must drop that reference.
1553          * The test for EXIT_ZOMBIE must occur while the runqueue locks are
1554          * still held, otherwise prev could be scheduled on another cpu, die
1555          * there before we look at prev->state, and then the reference would
1556          * be dropped twice.
1557          *              Manfred Spraul <manfred@colorfullife.com>
1558          */
1559         prev_task_flags = prev->flags;
1560         finish_arch_switch(prev);
1561         finish_lock_switch(rq, prev);
1562         if (mm)
1563                 mmdrop(mm);
1564         if (unlikely(prev_task_flags & PF_DEAD)) {
1565                 /*
1566                  * Remove function-return probe instances associated with this
1567                  * task and put them back on the free list.
1568                  */
1569                 kprobe_flush_task(prev);
1570                 put_task_struct(prev);
1571         }
1572 }
1573
1574 /**
1575  * schedule_tail - first thing a freshly forked thread must call.
1576  * @prev: the thread we just switched away from.
1577  */
1578 asmlinkage void schedule_tail(task_t *prev)
1579         __releases(rq->lock)
1580 {
1581         runqueue_t *rq = this_rq();
1582         finish_task_switch(rq, prev);
1583 #ifdef __ARCH_WANT_UNLOCKED_CTXSW
1584         /* In this case, finish_task_switch does not reenable preemption */
1585         preempt_enable();
1586 #endif
1587         if (current->set_child_tid)
1588                 put_user(current->pid, current->set_child_tid);
1589 }
1590
1591 /*
1592  * context_switch - switch to the new MM and the new
1593  * thread's register state.
1594  */
1595 static inline
1596 task_t * context_switch(runqueue_t *rq, task_t *prev, task_t *next)
1597 {
1598         struct mm_struct *mm = next->mm;
1599         struct mm_struct *oldmm = prev->active_mm;
1600
1601         if (unlikely(!mm)) {
1602                 next->active_mm = oldmm;
1603                 atomic_inc(&oldmm->mm_count);
1604                 enter_lazy_tlb(oldmm, next);
1605         } else
1606                 switch_mm(oldmm, mm, next);
1607
1608         if (unlikely(!prev->mm)) {
1609                 prev->active_mm = NULL;
1610                 WARN_ON(rq->prev_mm);
1611                 rq->prev_mm = oldmm;
1612         }
1613
1614         /* Here we just switch the register state and the stack. */
1615         switch_to(prev, next, prev);
1616
1617         return prev;
1618 }
1619
1620 /*
1621  * nr_running, nr_uninterruptible and nr_context_switches:
1622  *
1623  * externally visible scheduler statistics: current number of runnable
1624  * threads, current number of uninterruptible-sleeping threads, total
1625  * number of context switches performed since bootup.
1626  */
1627 unsigned long nr_running(void)
1628 {
1629         unsigned long i, sum = 0;
1630
1631         for_each_online_cpu(i)
1632                 sum += cpu_rq(i)->nr_running;
1633
1634         return sum;
1635 }
1636
1637 unsigned long nr_uninterruptible(void)
1638 {
1639         unsigned long i, sum = 0;
1640
1641         for_each_possible_cpu(i)
1642                 sum += cpu_rq(i)->nr_uninterruptible;
1643
1644         /*
1645          * Since we read the counters lockless, it might be slightly
1646          * inaccurate. Do not allow it to go below zero though:
1647          */
1648         if (unlikely((long)sum < 0))
1649                 sum = 0;
1650
1651         return sum;
1652 }
1653
1654 unsigned long long nr_context_switches(void)
1655 {
1656         unsigned long long i, sum = 0;
1657
1658         for_each_possible_cpu(i)
1659                 sum += cpu_rq(i)->nr_switches;
1660
1661         return sum;
1662 }
1663
1664 unsigned long nr_iowait(void)
1665 {
1666         unsigned long i, sum = 0;
1667
1668         for_each_possible_cpu(i)
1669                 sum += atomic_read(&cpu_rq(i)->nr_iowait);
1670
1671         return sum;
1672 }
1673
1674 unsigned long nr_active(void)
1675 {
1676         unsigned long i, running = 0, uninterruptible = 0;
1677
1678         for_each_online_cpu(i) {
1679                 running += cpu_rq(i)->nr_running;
1680                 uninterruptible += cpu_rq(i)->nr_uninterruptible;
1681         }
1682
1683         if (unlikely((long)uninterruptible < 0))
1684                 uninterruptible = 0;
1685
1686         return running + uninterruptible;
1687 }
1688
1689 #ifdef CONFIG_SMP
1690
1691 /*
1692  * double_rq_lock - safely lock two runqueues
1693  *
1694  * We must take them in cpu order to match code in
1695  * dependent_sleeper and wake_dependent_sleeper.
1696  *
1697  * Note this does not disable interrupts like task_rq_lock,
1698  * you need to do so manually before calling.
1699  */
1700 static void double_rq_lock(runqueue_t *rq1, runqueue_t *rq2)
1701         __acquires(rq1->lock)
1702         __acquires(rq2->lock)
1703 {
1704         if (rq1 == rq2) {
1705                 spin_lock(&rq1->lock);
1706                 __acquire(rq2->lock);   /* Fake it out ;) */
1707         } else {
1708                 if (rq1->cpu < rq2->cpu) {
1709                         spin_lock(&rq1->lock);
1710                         spin_lock(&rq2->lock);
1711                 } else {
1712                         spin_lock(&rq2->lock);
1713                         spin_lock(&rq1->lock);
1714                 }
1715         }
1716 }
1717
1718 /*
1719  * double_rq_unlock - safely unlock two runqueues
1720  *
1721  * Note this does not restore interrupts like task_rq_unlock,
1722  * you need to do so manually after calling.
1723  */
1724 static void double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2)
1725         __releases(rq1->lock)
1726         __releases(rq2->lock)
1727 {
1728         spin_unlock(&rq1->lock);
1729         if (rq1 != rq2)
1730                 spin_unlock(&rq2->lock);
1731         else
1732                 __release(rq2->lock);
1733 }
1734
1735 /*
1736  * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
1737  */
1738 static void double_lock_balance(runqueue_t *this_rq, runqueue_t *busiest)
1739         __releases(this_rq->lock)
1740         __acquires(busiest->lock)
1741         __acquires(this_rq->lock)
1742 {
1743         if (unlikely(!spin_trylock(&busiest->lock))) {
1744                 if (busiest->cpu < this_rq->cpu) {
1745                         spin_unlock(&this_rq->lock);
1746                         spin_lock(&busiest->lock);
1747                         spin_lock(&this_rq->lock);
1748                 } else
1749                         spin_lock(&busiest->lock);
1750         }
1751 }
1752
1753 /*
1754  * If dest_cpu is allowed for this process, migrate the task to it.
1755  * This is accomplished by forcing the cpu_allowed mask to only
1756  * allow dest_cpu, which will force the cpu onto dest_cpu.  Then
1757  * the cpu_allowed mask is restored.
1758  */
1759 static void sched_migrate_task(task_t *p, int dest_cpu)
1760 {
1761         migration_req_t req;
1762         runqueue_t *rq;
1763         unsigned long flags;
1764
1765         rq = task_rq_lock(p, &flags);
1766         if (!cpu_isset(dest_cpu, p->cpus_allowed)
1767             || unlikely(cpu_is_offline(dest_cpu)))
1768                 goto out;
1769
1770         /* force the process onto the specified CPU */
1771         if (migrate_task(p, dest_cpu, &req)) {
1772                 /* Need to wait for migration thread (might exit: take ref). */
1773                 struct task_struct *mt = rq->migration_thread;
1774                 get_task_struct(mt);
1775                 task_rq_unlock(rq, &flags);
1776                 wake_up_process(mt);
1777                 put_task_struct(mt);
1778                 wait_for_completion(&req.done);
1779                 return;
1780         }
1781 out:
1782         task_rq_unlock(rq, &flags);
1783 }
1784
1785 /*
1786  * sched_exec - execve() is a valuable balancing opportunity, because at
1787  * this point the task has the smallest effective memory and cache footprint.
1788  */
1789 void sched_exec(void)
1790 {
1791         int new_cpu, this_cpu = get_cpu();
1792         new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
1793         put_cpu();
1794         if (new_cpu != this_cpu)
1795                 sched_migrate_task(current, new_cpu);
1796 }
1797
1798 /*
1799  * pull_task - move a task from a remote runqueue to the local runqueue.
1800  * Both runqueues must be locked.
1801  */
1802 static
1803 void pull_task(runqueue_t *src_rq, prio_array_t *src_array, task_t *p,
1804                runqueue_t *this_rq, prio_array_t *this_array, int this_cpu)
1805 {
1806         dequeue_task(p, src_array);
1807         src_rq->nr_running--;
1808         set_task_cpu(p, this_cpu);
1809         this_rq->nr_running++;
1810         enqueue_task(p, this_array);
1811         p->timestamp = (p->timestamp - src_rq->timestamp_last_tick)
1812                                 + this_rq->timestamp_last_tick;
1813         /*
1814          * Note that idle threads have a prio of MAX_PRIO, for this test
1815          * to be always true for them.
1816          */
1817         if (TASK_PREEMPTS_CURR(p, this_rq))
1818                 resched_task(this_rq->curr);
1819 }
1820
1821 /*
1822  * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
1823  */
1824 static
1825 int can_migrate_task(task_t *p, runqueue_t *rq, int this_cpu,
1826                      struct sched_domain *sd, enum idle_type idle,
1827                      int *all_pinned)
1828 {
1829         /*
1830          * We do not migrate tasks that are:
1831          * 1) running (obviously), or
1832          * 2) cannot be migrated to this CPU due to cpus_allowed, or
1833          * 3) are cache-hot on their current CPU.
1834          */
1835         if (!cpu_isset(this_cpu, p->cpus_allowed))
1836                 return 0;
1837         *all_pinned = 0;
1838
1839         if (task_running(rq, p))
1840                 return 0;
1841
1842         /*
1843          * Aggressive migration if:
1844          * 1) task is cache cold, or
1845          * 2) too many balance attempts have failed.
1846          */
1847
1848         if (sd->nr_balance_failed > sd->cache_nice_tries)
1849                 return 1;
1850
1851         if (task_hot(p, rq->timestamp_last_tick, sd))
1852                 return 0;
1853         return 1;
1854 }
1855
1856 /*
1857  * move_tasks tries to move up to max_nr_move tasks from busiest to this_rq,
1858  * as part of a balancing operation within "domain". Returns the number of
1859  * tasks moved.
1860  *
1861  * Called with both runqueues locked.
1862  */
1863 static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest,
1864                       unsigned long max_nr_move, struct sched_domain *sd,
1865                       enum idle_type idle, int *all_pinned)
1866 {
1867         prio_array_t *array, *dst_array;
1868         struct list_head *head, *curr;
1869         int idx, pulled = 0, pinned = 0;
1870         task_t *tmp;
1871
1872         if (max_nr_move == 0)
1873                 goto out;
1874
1875         pinned = 1;
1876
1877         /*
1878          * We first consider expired tasks. Those will likely not be
1879          * executed in the near future, and they are most likely to
1880          * be cache-cold, thus switching CPUs has the least effect
1881          * on them.
1882          */
1883         if (busiest->expired->nr_active) {
1884                 array = busiest->expired;
1885                 dst_array = this_rq->expired;
1886         } else {
1887                 array = busiest->active;
1888                 dst_array = this_rq->active;
1889         }
1890
1891 new_array:
1892         /* Start searching at priority 0: */
1893         idx = 0;
1894 skip_bitmap:
1895         if (!idx)
1896                 idx = sched_find_first_bit(array->bitmap);
1897         else
1898                 idx = find_next_bit(array->bitmap, MAX_PRIO, idx);
1899         if (idx >= MAX_PRIO) {
1900                 if (array == busiest->expired && busiest->active->nr_active) {
1901                         array = busiest->active;
1902                         dst_array = this_rq->active;
1903                         goto new_array;
1904                 }
1905                 goto out;
1906         }
1907
1908         head = array->queue + idx;
1909         curr = head->prev;
1910 skip_queue:
1911         tmp = list_entry(curr, task_t, run_list);
1912
1913         curr = curr->prev;
1914
1915         if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle, &pinned)) {
1916                 if (curr != head)
1917                         goto skip_queue;
1918                 idx++;
1919                 goto skip_bitmap;
1920         }
1921
1922 #ifdef CONFIG_SCHEDSTATS
1923         if (task_hot(tmp, busiest->timestamp_last_tick, sd))
1924                 schedstat_inc(sd, lb_hot_gained[idle]);
1925 #endif
1926
1927         pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu);
1928         pulled++;
1929
1930         /* We only want to steal up to the prescribed number of tasks. */
1931         if (pulled < max_nr_move) {
1932                 if (curr != head)
1933                         goto skip_queue;
1934                 idx++;
1935                 goto skip_bitmap;
1936         }
1937 out:
1938         /*
1939          * Right now, this is the only place pull_task() is called,
1940          * so we can safely collect pull_task() stats here rather than
1941          * inside pull_task().
1942          */
1943         schedstat_add(sd, lb_gained[idle], pulled);
1944
1945         if (all_pinned)
1946                 *all_pinned = pinned;
1947         return pulled;
1948 }
1949
1950 /*
1951  * find_busiest_group finds and returns the busiest CPU group within the
1952  * domain. It calculates and returns the number of tasks which should be
1953  * moved to restore balance via the imbalance parameter.
1954  */
1955 static struct sched_group *
1956 find_busiest_group(struct sched_domain *sd, int this_cpu,
1957                    unsigned long *imbalance, enum idle_type idle, int *sd_idle)
1958 {
1959         struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
1960         unsigned long max_load, avg_load, total_load, this_load, total_pwr;
1961         unsigned long max_pull;
1962         int load_idx;
1963
1964         max_load = this_load = total_load = total_pwr = 0;
1965         if (idle == NOT_IDLE)
1966                 load_idx = sd->busy_idx;
1967         else if (idle == NEWLY_IDLE)
1968                 load_idx = sd->newidle_idx;
1969         else
1970                 load_idx = sd->idle_idx;
1971
1972         do {
1973                 unsigned long load;
1974                 int local_group;
1975                 int i;
1976
1977                 local_group = cpu_isset(this_cpu, group->cpumask);
1978
1979                 /* Tally up the load of all CPUs in the group */
1980                 avg_load = 0;
1981
1982                 for_each_cpu_mask(i, group->cpumask) {
1983                         if (*sd_idle && !idle_cpu(i))
1984                                 *sd_idle = 0;
1985
1986                         /* Bias balancing toward cpus of our domain */
1987                         if (local_group)
1988                                 load = target_load(i, load_idx);
1989                         else
1990                                 load = source_load(i, load_idx);
1991
1992                         avg_load += load;
1993                 }
1994
1995                 total_load += avg_load;
1996                 total_pwr += group->cpu_power;
1997
1998                 /* Adjust by relative CPU power of the group */
1999                 avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
2000
2001                 if (local_group) {
2002                         this_load = avg_load;
2003                         this = group;
2004                 } else if (avg_load > max_load) {
2005                         max_load = avg_load;
2006                         busiest = group;
2007                 }
2008                 group = group->next;
2009         } while (group != sd->groups);
2010
2011         if (!busiest || this_load >= max_load || max_load <= SCHED_LOAD_SCALE)
2012                 goto out_balanced;
2013
2014         avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
2015
2016         if (this_load >= avg_load ||
2017                         100*max_load <= sd->imbalance_pct*this_load)
2018                 goto out_balanced;
2019
2020         /*
2021          * We're trying to get all the cpus to the average_load, so we don't
2022          * want to push ourselves above the average load, nor do we wish to
2023          * reduce the max loaded cpu below the average load, as either of these
2024          * actions would just result in more rebalancing later, and ping-pong
2025          * tasks around. Thus we look for the minimum possible imbalance.
2026          * Negative imbalances (*we* are more loaded than anyone else) will
2027          * be counted as no imbalance for these purposes -- we can't fix that
2028          * by pulling tasks to us.  Be careful of negative numbers as they'll
2029          * appear as very large values with unsigned longs.
2030          */
2031
2032         /* Don't want to pull so many tasks that a group would go idle */
2033         max_pull = min(max_load - avg_load, max_load - SCHED_LOAD_SCALE);
2034
2035         /* How much load to actually move to equalise the imbalance */
2036         *imbalance = min(max_pull * busiest->cpu_power,
2037                                 (avg_load - this_load) * this->cpu_power)
2038                         / SCHED_LOAD_SCALE;
2039
2040         if (*imbalance < SCHED_LOAD_SCALE) {
2041                 unsigned long pwr_now = 0, pwr_move = 0;
2042                 unsigned long tmp;
2043
2044                 if (max_load - this_load >= SCHED_LOAD_SCALE*2) {
2045                         *imbalance = 1;
2046                         return busiest;
2047                 }
2048
2049                 /*
2050                  * OK, we don't have enough imbalance to justify moving tasks,
2051                  * however we may be able to increase total CPU power used by
2052                  * moving them.
2053                  */
2054
2055                 pwr_now += busiest->cpu_power*min(SCHED_LOAD_SCALE, max_load);
2056                 pwr_now += this->cpu_power*min(SCHED_LOAD_SCALE, this_load);
2057                 pwr_now /= SCHED_LOAD_SCALE;
2058
2059                 /* Amount of load we'd subtract */
2060                 tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/busiest->cpu_power;
2061                 if (max_load > tmp)
2062                         pwr_move += busiest->cpu_power*min(SCHED_LOAD_SCALE,
2063                                                         max_load - tmp);
2064
2065                 /* Amount of load we'd add */
2066                 if (max_load*busiest->cpu_power <
2067                                 SCHED_LOAD_SCALE*SCHED_LOAD_SCALE)
2068                         tmp = max_load*busiest->cpu_power/this->cpu_power;
2069                 else
2070                         tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/this->cpu_power;
2071                 pwr_move += this->cpu_power*min(SCHED_LOAD_SCALE, this_load + tmp);
2072                 pwr_move /= SCHED_LOAD_SCALE;
2073
2074                 /* Move if we gain throughput */
2075                 if (pwr_move <= pwr_now)
2076                         goto out_balanced;
2077
2078                 *imbalance = 1;
2079                 return busiest;
2080         }
2081
2082         /* Get rid of the scaling factor, rounding down as we divide */
2083         *imbalance = *imbalance / SCHED_LOAD_SCALE;
2084         return busiest;
2085
2086 out_balanced:
2087
2088         *imbalance = 0;
2089         return NULL;
2090 }
2091
2092 /*
2093  * find_busiest_queue - find the busiest runqueue among the cpus in group.
2094  */
2095 static runqueue_t *find_busiest_queue(struct sched_group *group,
2096         enum idle_type idle)
2097 {
2098         unsigned long load, max_load = 0;
2099         runqueue_t *busiest = NULL;
2100         int i;
2101
2102         for_each_cpu_mask(i, group->cpumask) {
2103                 load = source_load(i, 0);
2104
2105                 if (load > max_load) {
2106                         max_load = load;
2107                         busiest = cpu_rq(i);
2108                 }
2109         }
2110
2111         return busiest;
2112 }
2113
2114 /*
2115  * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
2116  * so long as it is large enough.
2117  */
2118 #define MAX_PINNED_INTERVAL     512
2119
2120 /*
2121  * Check this_cpu to ensure it is balanced within domain. Attempt to move
2122  * tasks if there is an imbalance.
2123  *
2124  * Called with this_rq unlocked.
2125  */
2126 static int load_balance(int this_cpu, runqueue_t *this_rq,
2127                         struct sched_domain *sd, enum idle_type idle)
2128 {
2129         struct sched_group *group;
2130         runqueue_t *busiest;
2131         unsigned long imbalance;
2132         int nr_moved, all_pinned = 0;
2133         int active_balance = 0;
2134         int sd_idle = 0;
2135
2136         if (idle != NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER)
2137                 sd_idle = 1;
2138
2139         schedstat_inc(sd, lb_cnt[idle]);
2140
2141         group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle);
2142         if (!group) {
2143                 schedstat_inc(sd, lb_nobusyg[idle]);
2144                 goto out_balanced;
2145         }
2146
2147         busiest = find_busiest_queue(group, idle);
2148         if (!busiest) {
2149                 schedstat_inc(sd, lb_nobusyq[idle]);
2150                 goto out_balanced;
2151         }
2152
2153         BUG_ON(busiest == this_rq);
2154
2155         schedstat_add(sd, lb_imbalance[idle], imbalance);
2156
2157         nr_moved = 0;
2158         if (busiest->nr_running > 1) {
2159                 /*
2160                  * Attempt to move tasks. If find_busiest_group has found
2161                  * an imbalance but busiest->nr_running <= 1, the group is
2162                  * still unbalanced. nr_moved simply stays zero, so it is
2163                  * correctly treated as an imbalance.
2164                  */
2165                 double_rq_lock(this_rq, busiest);
2166                 nr_moved = move_tasks(this_rq, this_cpu, busiest,
2167                                         imbalance, sd, idle, &all_pinned);
2168                 double_rq_unlock(this_rq, busiest);
2169
2170                 /* All tasks on this runqueue were pinned by CPU affinity */
2171                 if (unlikely(all_pinned))
2172                         goto out_balanced;
2173         }
2174
2175         if (!nr_moved) {
2176                 schedstat_inc(sd, lb_failed[idle]);
2177                 sd->nr_balance_failed++;
2178
2179                 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
2180
2181                         spin_lock(&busiest->lock);
2182
2183                         /* don't kick the migration_thread, if the curr
2184                          * task on busiest cpu can't be moved to this_cpu
2185                          */
2186                         if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) {
2187                                 spin_unlock(&busiest->lock);
2188                                 all_pinned = 1;
2189                                 goto out_one_pinned;
2190                         }
2191
2192                         if (!busiest->active_balance) {
2193                                 busiest->active_balance = 1;
2194                                 busiest->push_cpu = this_cpu;
2195                                 active_balance = 1;
2196                         }
2197                         spin_unlock(&busiest->lock);
2198                         if (active_balance)
2199                                 wake_up_process(busiest->migration_thread);
2200
2201                         /*
2202                          * We've kicked active balancing, reset the failure
2203                          * counter.
2204                          */
2205                         sd->nr_balance_failed = sd->cache_nice_tries+1;
2206                 }
2207         } else
2208                 sd->nr_balance_failed = 0;
2209
2210         if (likely(!active_balance)) {
2211                 /* We were unbalanced, so reset the balancing interval */
2212                 sd->balance_interval = sd->min_interval;
2213         } else {
2214                 /*
2215                  * If we've begun active balancing, start to back off. This
2216                  * case may not be covered by the all_pinned logic if there
2217                  * is only 1 task on the busy runqueue (because we don't call
2218                  * move_tasks).
2219                  */
2220                 if (sd->balance_interval < sd->max_interval)
2221                         sd->balance_interval *= 2;
2222         }
2223
2224         if (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER)
2225                 return -1;
2226         return nr_moved;
2227
2228 out_balanced:
2229         schedstat_inc(sd, lb_balanced[idle]);
2230
2231         sd->nr_balance_failed = 0;
2232
2233 out_one_pinned:
2234         /* tune up the balancing interval */
2235         if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
2236                         (sd->balance_interval < sd->max_interval))
2237                 sd->balance_interval *= 2;
2238
2239         if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER)
2240                 return -1;
2241         return 0;
2242 }
2243
2244 /*
2245  * Check this_cpu to ensure it is balanced within domain. Attempt to move
2246  * tasks if there is an imbalance.
2247  *
2248  * Called from schedule when this_rq is about to become idle (NEWLY_IDLE).
2249  * this_rq is locked.
2250  */
2251 static int load_balance_newidle(int this_cpu, runqueue_t *this_rq,
2252                                 struct sched_domain *sd)
2253 {
2254         struct sched_group *group;
2255         runqueue_t *busiest = NULL;
2256         unsigned long imbalance;
2257         int nr_moved = 0;
2258         int sd_idle = 0;
2259
2260         if (sd->flags & SD_SHARE_CPUPOWER)
2261                 sd_idle = 1;
2262
2263         schedstat_inc(sd, lb_cnt[NEWLY_IDLE]);
2264         group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE, &sd_idle);
2265         if (!group) {
2266                 schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]);
2267                 goto out_balanced;
2268         }
2269
2270         busiest = find_busiest_queue(group, NEWLY_IDLE);
2271         if (!busiest) {
2272                 schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]);
2273                 goto out_balanced;
2274         }
2275
2276         BUG_ON(busiest == this_rq);
2277
2278         schedstat_add(sd, lb_imbalance[NEWLY_IDLE], imbalance);
2279
2280         nr_moved = 0;
2281         if (busiest->nr_running > 1) {
2282                 /* Attempt to move tasks */
2283                 double_lock_balance(this_rq, busiest);
2284                 nr_moved = move_tasks(this_rq, this_cpu, busiest,
2285                                         imbalance, sd, NEWLY_IDLE, NULL);
2286                 spin_unlock(&busiest->lock);
2287         }
2288
2289         if (!nr_moved) {
2290                 schedstat_inc(sd, lb_failed[NEWLY_IDLE]);
2291                 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER)
2292                         return -1;
2293         } else
2294                 sd->nr_balance_failed = 0;
2295
2296         return nr_moved;
2297
2298 out_balanced:
2299         schedstat_inc(sd, lb_balanced[NEWLY_IDLE]);
2300         if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER)
2301                 return -1;
2302         sd->nr_balance_failed = 0;
2303         return 0;
2304 }
2305
2306 /*
2307  * idle_balance is called by schedule() if this_cpu is about to become
2308  * idle. Attempts to pull tasks from other CPUs.
2309  */
2310 static void idle_balance(int this_cpu, runqueue_t *this_rq)
2311 {
2312         struct sched_domain *sd;
2313
2314         for_each_domain(this_cpu, sd) {
2315                 if (sd->flags & SD_BALANCE_NEWIDLE) {
2316                         if (load_balance_newidle(this_cpu, this_rq, sd)) {
2317                                 /* We've pulled tasks over so stop searching */
2318                                 break;
2319                         }
2320                 }
2321         }
2322 }
2323
2324 /*
2325  * active_load_balance is run by migration threads. It pushes running tasks
2326  * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
2327  * running on each physical CPU where possible, and avoids physical /
2328  * logical imbalances.
2329  *
2330  * Called with busiest_rq locked.
2331  */
2332 static void active_load_balance(runqueue_t *busiest_rq, int busiest_cpu)
2333 {
2334         struct sched_domain *sd;
2335         runqueue_t *target_rq;
2336         int target_cpu = busiest_rq->push_cpu;
2337
2338         if (busiest_rq->nr_running <= 1)
2339                 /* no task to move */
2340                 return;
2341
2342         target_rq = cpu_rq(target_cpu);
2343
2344         /*
2345          * This condition is "impossible", if it occurs
2346          * we need to fix it.  Originally reported by
2347          * Bjorn Helgaas on a 128-cpu setup.
2348          */
2349         BUG_ON(busiest_rq == target_rq);
2350
2351         /* move a task from busiest_rq to target_rq */
2352         double_lock_balance(busiest_rq, target_rq);
2353
2354         /* Search for an sd spanning us and the target CPU. */
2355         for_each_domain(target_cpu, sd)
2356                 if ((sd->flags & SD_LOAD_BALANCE) &&
2357                         cpu_isset(busiest_cpu, sd->span))
2358                                 break;
2359
2360         if (unlikely(sd == NULL))
2361                 goto out;
2362
2363         schedstat_inc(sd, alb_cnt);
2364
2365         if (move_tasks(target_rq, target_cpu, busiest_rq, 1, sd, SCHED_IDLE, NULL))
2366                 schedstat_inc(sd, alb_pushed);
2367         else
2368                 schedstat_inc(sd, alb_failed);
2369 out:
2370         spin_unlock(&target_rq->lock);
2371 }
2372
2373 /*
2374  * rebalance_tick will get called every timer tick, on every CPU.
2375  *
2376  * It checks each scheduling domain to see if it is due to be balanced,
2377  * and initiates a balancing operation if so.
2378  *
2379  * Balancing parameters are set up in arch_init_sched_domains.
2380  */
2381
2382 /* Don't have all balancing operations going off at once */
2383 #define CPU_OFFSET(cpu) (HZ * cpu / NR_CPUS)
2384
2385 static void rebalance_tick(int this_cpu, runqueue_t *this_rq,
2386                            enum idle_type idle)
2387 {
2388         unsigned long old_load, this_load;
2389         unsigned long j = jiffies + CPU_OFFSET(this_cpu);
2390         struct sched_domain *sd;
2391         int i;
2392
2393         this_load = this_rq->nr_running * SCHED_LOAD_SCALE;
2394         /* Update our load */
2395         for (i = 0; i < 3; i++) {
2396                 unsigned long new_load = this_load;
2397                 int scale = 1 << i;
2398                 old_load = this_rq->cpu_load[i];
2399                 /*
2400                  * Round up the averaging division if load is increasing. This
2401                  * prevents us from getting stuck on 9 if the load is 10, for
2402                  * example.
2403                  */
2404                 if (new_load > old_load)
2405                         new_load += scale-1;
2406                 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) / scale;
2407         }
2408
2409         for_each_domain(this_cpu, sd) {
2410                 unsigned long interval;
2411
2412                 if (!(sd->flags & SD_LOAD_BALANCE))
2413                         continue;
2414
2415                 interval = sd->balance_interval;
2416                 if (idle != SCHED_IDLE)
2417                         interval *= sd->busy_factor;
2418
2419                 /* scale ms to jiffies */
2420                 interval = msecs_to_jiffies(interval);
2421                 if (unlikely(!interval))
2422                         interval = 1;
2423
2424                 if (j - sd->last_balance >= interval) {
2425                         if (load_balance(this_cpu, this_rq, sd, idle)) {
2426                                 /*
2427                                  * We've pulled tasks over so either we're no
2428                                  * longer idle, or one of our SMT siblings is
2429                                  * not idle.
2430                                  */
2431                                 idle = NOT_IDLE;
2432                         }
2433                         sd->last_balance += interval;
2434                 }
2435         }
2436 }
2437 #else
2438 /*
2439  * on UP we do not need to balance between CPUs:
2440  */
2441 static inline void rebalance_tick(int cpu, runqueue_t *rq, enum idle_type idle)
2442 {
2443 }
2444 static inline void idle_balance(int cpu, runqueue_t *rq)
2445 {
2446 }
2447 #endif
2448
2449 static inline int wake_priority_sleeper(runqueue_t *rq)
2450 {
2451         int ret = 0;
2452 #ifdef CONFIG_SCHED_SMT
2453         spin_lock(&rq->lock);
2454         /*
2455          * If an SMT sibling task has been put to sleep for priority
2456          * reasons reschedule the idle task to see if it can now run.
2457          */
2458         if (rq->nr_running) {
2459                 resched_task(rq->idle);
2460                 ret = 1;
2461         }
2462         spin_unlock(&rq->lock);
2463 #endif
2464         return ret;
2465 }
2466
2467 DEFINE_PER_CPU(struct kernel_stat, kstat);
2468
2469 EXPORT_PER_CPU_SYMBOL(kstat);
2470
2471 /*
2472  * This is called on clock ticks and on context switches.
2473  * Bank in p->sched_time the ns elapsed since the last tick or switch.
2474  */
2475 static inline void update_cpu_clock(task_t *p, runqueue_t *rq,
2476                                     unsigned long long now)
2477 {
2478         unsigned long long last = max(p->timestamp, rq->timestamp_last_tick);
2479         p->sched_time += now - last;
2480 }
2481
2482 /*
2483  * Return current->sched_time plus any more ns on the sched_clock
2484  * that have not yet been banked.
2485  */
2486 unsigned long long current_sched_time(const task_t *tsk)
2487 {
2488         unsigned long long ns;
2489         unsigned long flags;
2490         local_irq_save(flags);
2491         ns = max(tsk->timestamp, task_rq(tsk)->timestamp_last_tick);
2492         ns = tsk->sched_time + (sched_clock() - ns);
2493         local_irq_restore(flags);
2494         return ns;
2495 }
2496
2497 /*
2498  * We place interactive tasks back into the active array, if possible.
2499  *
2500  * To guarantee that this does not starve expired tasks we ignore the
2501  * interactivity of a task if the first expired task had to wait more
2502  * than a 'reasonable' amount of time. This deadline timeout is
2503  * load-dependent, as the frequency of array switched decreases with
2504  * increasing number of running tasks. We also ignore the interactivity
2505  * if a better static_prio task has expired:
2506  */
2507 #define EXPIRED_STARVING(rq) \
2508         ((STARVATION_LIMIT && ((rq)->expired_timestamp && \
2509                 (jiffies - (rq)->expired_timestamp >= \
2510                         STARVATION_LIMIT * ((rq)->nr_running) + 1))) || \
2511                         ((rq)->curr->static_prio > (rq)->best_expired_prio))
2512
2513 /*
2514  * Account user cpu time to a process.
2515  * @p: the process that the cpu time gets accounted to
2516  * @hardirq_offset: the offset to subtract from hardirq_count()
2517  * @cputime: the cpu time spent in user space since the last update
2518  */
2519 void account_user_time(struct task_struct *p, cputime_t cputime)
2520 {
2521         struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
2522         cputime64_t tmp;
2523
2524         p->utime = cputime_add(p->utime, cputime);
2525
2526         /* Add user time to cpustat. */
2527         tmp = cputime_to_cputime64(cputime);
2528         if (TASK_NICE(p) > 0)
2529                 cpustat->nice = cputime64_add(cpustat->nice, tmp);
2530         else
2531                 cpustat->user = cputime64_add(cpustat->user, tmp);
2532 }
2533
2534 /*
2535  * Account system cpu time to a process.
2536  * @p: the process that the cpu time gets accounted to
2537  * @hardirq_offset: the offset to subtract from hardirq_count()
2538  * @cputime: the cpu time spent in kernel space since the last update
2539  */
2540 void account_system_time(struct task_struct *p, int hardirq_offset,
2541                          cputime_t cputime)
2542 {
2543         struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
2544         runqueue_t *rq = this_rq();
2545         cputime64_t tmp;
2546
2547         p->stime = cputime_add(p->stime, cputime);
2548
2549         /* Add system time to cpustat. */
2550         tmp = cputime_to_cputime64(cputime);
2551         if (hardirq_count() - hardirq_offset)
2552                 cpustat->irq = cputime64_add(cpustat->irq, tmp);
2553         else if (softirq_count())
2554                 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
2555         else if (p != rq->idle)
2556                 cpustat->system = cputime64_add(cpustat->system, tmp);
2557         else if (atomic_read(&rq->nr_iowait) > 0)
2558                 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
2559         else
2560                 cpustat->idle = cputime64_add(cpustat->idle, tmp);
2561         /* Account for system time used */
2562         acct_update_integrals(p);
2563 }
2564
2565 /*
2566  * Account for involuntary wait time.
2567  * @p: the process from which the cpu time has been stolen
2568  * @steal: the cpu time spent in involuntary wait
2569  */
2570 void account_steal_time(struct task_struct *p, cputime_t steal)
2571 {
2572         struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
2573         cputime64_t tmp = cputime_to_cputime64(steal);
2574         runqueue_t *rq = this_rq();
2575
2576         if (p == rq->idle) {
2577                 p->stime = cputime_add(p->stime, steal);
2578                 if (atomic_read(&rq->nr_iowait) > 0)
2579                         cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
2580                 else
2581                         cpustat->idle = cputime64_add(cpustat->idle, tmp);
2582         } else
2583                 cpustat->steal = cputime64_add(cpustat->steal, tmp);
2584 }
2585
2586 /*
2587  * This function gets called by the timer code, with HZ frequency.
2588  * We call it with interrupts disabled.
2589  *
2590  * It also gets called by the fork code, when changing the parent's
2591  * timeslices.
2592  */
2593 void scheduler_tick(void)
2594 {
2595         int cpu = smp_processor_id();
2596         runqueue_t *rq = this_rq();
2597         task_t *p = current;
2598         unsigned long long now = sched_clock();
2599
2600         update_cpu_clock(p, rq, now);
2601
2602         rq->timestamp_last_tick = now;
2603
2604         if (p == rq->idle) {
2605                 if (wake_priority_sleeper(rq))
2606                         goto out;
2607                 rebalance_tick(cpu, rq, SCHED_IDLE);
2608                 return;
2609         }
2610
2611         /* Task might have expired already, but not scheduled off yet */
2612         if (p->array != rq->active) {
2613                 set_tsk_need_resched(p);
2614                 goto out;
2615         }
2616         spin_lock(&rq->lock);
2617         /*
2618          * The task was running during this tick - update the
2619          * time slice counter. Note: we do not update a thread's
2620          * priority until it either goes to sleep or uses up its
2621          * timeslice. This makes it possible for interactive tasks
2622          * to use up their timeslices at their highest priority levels.
2623          */
2624         if (rt_task(p)) {
2625                 /*
2626                  * RR tasks need a special form of timeslice management.
2627                  * FIFO tasks have no timeslices.
2628                  */
2629                 if ((p->policy == SCHED_RR) && !--p->time_slice) {
2630                         p->time_slice = task_timeslice(p);
2631                         p->first_time_slice = 0;
2632                         set_tsk_need_resched(p);
2633
2634                         /* put it at the end of the queue: */
2635                         requeue_task(p, rq->active);
2636                 }
2637                 goto out_unlock;
2638         }
2639         if (!--p->time_slice) {
2640                 dequeue_task(p, rq->active);
2641                 set_tsk_need_resched(p);
2642                 p->prio = effective_prio(p);
2643                 p->time_slice = task_timeslice(p);
2644                 p->first_time_slice = 0;
2645
2646                 if (!rq->expired_timestamp)
2647                         rq->expired_timestamp = jiffies;
2648                 if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) {
2649                         enqueue_task(p, rq->expired);
2650                         if (p->static_prio < rq->best_expired_prio)
2651                                 rq->best_expired_prio = p->static_prio;
2652                 } else
2653                         enqueue_task(p, rq->active);
2654         } else {
2655                 /*
2656                  * Prevent a too long timeslice allowing a task to monopolize
2657                  * the CPU. We do this by splitting up the timeslice into
2658                  * smaller pieces.
2659                  *
2660                  * Note: this does not mean the task's timeslices expire or
2661                  * get lost in any way, they just might be preempted by
2662                  * another task of equal priority. (one with higher
2663                  * priority would have preempted this task already.) We
2664                  * requeue this task to the end of the list on this priority
2665                  * level, which is in essence a round-robin of tasks with
2666                  * equal priority.
2667                  *
2668                  * This only applies to tasks in the interactive
2669                  * delta range with at least TIMESLICE_GRANULARITY to requeue.
2670                  */
2671                 if (TASK_INTERACTIVE(p) && !((task_timeslice(p) -
2672                         p->time_slice) % TIMESLICE_GRANULARITY(p)) &&
2673                         (p->time_slice >= TIMESLICE_GRANULARITY(p)) &&
2674                         (p->array == rq->active)) {
2675
2676                         requeue_task(p, rq->active);
2677                         set_tsk_need_resched(p);
2678                 }
2679         }
2680 out_unlock:
2681         spin_unlock(&rq->lock);
2682 out:
2683         rebalance_tick(cpu, rq, NOT_IDLE);
2684 }
2685
2686 #ifdef CONFIG_SCHED_SMT
2687 static inline void wakeup_busy_runqueue(runqueue_t *rq)
2688 {
2689         /* If an SMT runqueue is sleeping due to priority reasons wake it up */
2690         if (rq->curr == rq->idle && rq->nr_running)
2691                 resched_task(rq->idle);
2692 }
2693
2694 static void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq)
2695 {
2696         struct sched_domain *tmp, *sd = NULL;
2697         cpumask_t sibling_map;
2698         int i;
2699
2700         for_each_domain(this_cpu, tmp)
2701                 if (tmp->flags & SD_SHARE_CPUPOWER)
2702                         sd = tmp;
2703
2704         if (!sd)
2705                 return;
2706
2707         /*
2708          * Unlock the current runqueue because we have to lock in
2709          * CPU order to avoid deadlocks. Caller knows that we might
2710          * unlock. We keep IRQs disabled.
2711          */
2712         spin_unlock(&this_rq->lock);
2713
2714         sibling_map = sd->span;
2715
2716         for_each_cpu_mask(i, sibling_map)
2717                 spin_lock(&cpu_rq(i)->lock);
2718         /*
2719          * We clear this CPU from the mask. This both simplifies the
2720          * inner loop and keps this_rq locked when we exit:
2721          */
2722         cpu_clear(this_cpu, sibling_map);
2723
2724         for_each_cpu_mask(i, sibling_map) {
2725                 runqueue_t *smt_rq = cpu_rq(i);
2726
2727                 wakeup_busy_runqueue(smt_rq);
2728         }
2729
2730         for_each_cpu_mask(i, sibling_map)
2731                 spin_unlock(&cpu_rq(i)->lock);
2732         /*
2733          * We exit with this_cpu's rq still held and IRQs
2734          * still disabled:
2735          */
2736 }
2737
2738 /*
2739  * number of 'lost' timeslices this task wont be able to fully
2740  * utilize, if another task runs on a sibling. This models the
2741  * slowdown effect of other tasks running on siblings:
2742  */
2743 static inline unsigned long smt_slice(task_t *p, struct sched_domain *sd)
2744 {
2745         return p->time_slice * (100 - sd->per_cpu_gain) / 100;
2746 }
2747
2748 static int dependent_sleeper(int this_cpu, runqueue_t *this_rq)
2749 {
2750         struct sched_domain *tmp, *sd = NULL;
2751         cpumask_t sibling_map;
2752         prio_array_t *array;
2753         int ret = 0, i;
2754         task_t *p;
2755
2756         for_each_domain(this_cpu, tmp)
2757                 if (tmp->flags & SD_SHARE_CPUPOWER)
2758                         sd = tmp;
2759
2760         if (!sd)
2761                 return 0;
2762
2763         /*
2764          * The same locking rules and details apply as for
2765          * wake_sleeping_dependent():
2766          */
2767         spin_unlock(&this_rq->lock);
2768         sibling_map = sd->span;
2769         for_each_cpu_mask(i, sibling_map)
2770                 spin_lock(&cpu_rq(i)->lock);
2771         cpu_clear(this_cpu, sibling_map);
2772
2773         /*
2774          * Establish next task to be run - it might have gone away because
2775          * we released the runqueue lock above:
2776          */
2777         if (!this_rq->nr_running)
2778                 goto out_unlock;
2779         array = this_rq->active;
2780         if (!array->nr_active)
2781                 array = this_rq->expired;
2782         BUG_ON(!array->nr_active);
2783
2784         p = list_entry(array->queue[sched_find_first_bit(array->bitmap)].next,
2785                 task_t, run_list);
2786
2787         for_each_cpu_mask(i, sibling_map) {
2788                 runqueue_t *smt_rq = cpu_rq(i);
2789                 task_t *smt_curr = smt_rq->curr;
2790
2791                 /* Kernel threads do not participate in dependent sleeping */
2792                 if (!p->mm || !smt_curr->mm || rt_task(p))
2793                         goto check_smt_task;
2794
2795                 /*
2796                  * If a user task with lower static priority than the
2797                  * running task on the SMT sibling is trying to schedule,
2798                  * delay it till there is proportionately less timeslice
2799                  * left of the sibling task to prevent a lower priority
2800                  * task from using an unfair proportion of the
2801                  * physical cpu's resources. -ck
2802                  */
2803                 if (rt_task(smt_curr)) {
2804                         /*
2805                          * With real time tasks we run non-rt tasks only
2806                          * per_cpu_gain% of the time.
2807                          */
2808                         if ((jiffies % DEF_TIMESLICE) >
2809                                 (sd->per_cpu_gain * DEF_TIMESLICE / 100))
2810                                         ret = 1;
2811                 } else
2812                         if (smt_curr->static_prio < p->static_prio &&
2813                                 !TASK_PREEMPTS_CURR(p, smt_rq) &&
2814                                 smt_slice(smt_curr, sd) > task_timeslice(p))
2815                                         ret = 1;
2816
2817 check_smt_task:
2818                 if ((!smt_curr->mm && smt_curr != smt_rq->idle) ||
2819                         rt_task(smt_curr))
2820                                 continue;
2821                 if (!p->mm) {
2822                         wakeup_busy_runqueue(smt_rq);
2823                         continue;
2824                 }
2825
2826                 /*
2827                  * Reschedule a lower priority task on the SMT sibling for
2828                  * it to be put to sleep, or wake it up if it has been put to
2829                  * sleep for priority reasons to see if it should run now.
2830                  */
2831                 if (rt_task(p)) {
2832                         if ((jiffies % DEF_TIMESLICE) >
2833                                 (sd->per_cpu_gain * DEF_TIMESLICE / 100))
2834                                         resched_task(smt_curr);
2835                 } else {
2836                         if (TASK_PREEMPTS_CURR(p, smt_rq) &&
2837                                 smt_slice(p, sd) > task_timeslice(smt_curr))
2838                                         resched_task(smt_curr);
2839                         else
2840                                 wakeup_busy_runqueue(smt_rq);
2841                 }
2842         }
2843 out_unlock:
2844         for_each_cpu_mask(i, sibling_map)
2845                 spin_unlock(&cpu_rq(i)->lock);
2846         return ret;
2847 }
2848 #else
2849 static inline void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq)
2850 {
2851 }
2852
2853 static inline int dependent_sleeper(int this_cpu, runqueue_t *this_rq)
2854 {
2855         return 0;
2856 }
2857 #endif
2858
2859 #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
2860
2861 void fastcall add_preempt_count(int val)
2862 {
2863         /*
2864          * Underflow?
2865          */
2866         BUG_ON((preempt_count() < 0));
2867         preempt_count() += val;
2868         /*
2869          * Spinlock count overflowing soon?
2870          */
2871         BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10);
2872 }
2873 EXPORT_SYMBOL(add_preempt_count);
2874
2875 void fastcall sub_preempt_count(int val)
2876 {
2877         /*
2878          * Underflow?
2879          */
2880         BUG_ON(val > preempt_count());
2881         /*
2882          * Is the spinlock portion underflowing?
2883          */
2884         BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK));
2885         preempt_count() -= val;
2886 }
2887 EXPORT_SYMBOL(sub_preempt_count);
2888
2889 #endif
2890
2891 static inline int interactive_sleep(enum sleep_type sleep_type)
2892 {
2893         return (sleep_type == SLEEP_INTERACTIVE ||
2894                 sleep_type == SLEEP_INTERRUPTED);
2895 }
2896
2897 /*
2898  * schedule() is the main scheduler function.
2899  */
2900 asmlinkage void __sched schedule(void)
2901 {
2902         long *switch_count;
2903         task_t *prev, *next;
2904         runqueue_t *rq;
2905         prio_array_t *array;
2906         struct list_head *queue;
2907         unsigned long long now;
2908         unsigned long run_time;
2909         int cpu, idx, new_prio;
2910
2911         /*
2912          * Test if we are atomic.  Since do_exit() needs to call into
2913          * schedule() atomically, we ignore that path for now.
2914          * Otherwise, whine if we are scheduling when we should not be.
2915          */
2916         if (unlikely(in_atomic() && !current->exit_state)) {
2917                 printk(KERN_ERR "BUG: scheduling while atomic: "
2918                         "%s/0x%08x/%d\n",
2919                         current->comm, preempt_count(), current->pid);
2920                 dump_stack();
2921         }
2922         profile_hit(SCHED_PROFILING, __builtin_return_address(0));
2923
2924 need_resched:
2925         preempt_disable();
2926         prev = current;
2927         release_kernel_lock(prev);
2928 need_resched_nonpreemptible:
2929         rq = this_rq();
2930
2931         /*
2932          * The idle thread is not allowed to schedule!
2933          * Remove this check after it has been exercised a bit.
2934          */
2935         if (unlikely(prev == rq->idle) && prev->state != TASK_RUNNING) {
2936                 printk(KERN_ERR "bad: scheduling from the idle thread!\n");
2937                 dump_stack();
2938         }
2939
2940         schedstat_inc(rq, sched_cnt);
2941         now = sched_clock();
2942         if (likely((long long)(now - prev->timestamp) < NS_MAX_SLEEP_AVG)) {
2943                 run_time = now - prev->timestamp;
2944                 if (unlikely((long long)(now - prev->timestamp) < 0))
2945                         run_time = 0;
2946         } else
2947                 run_time = NS_MAX_SLEEP_AVG;
2948
2949         /*
2950          * Tasks charged proportionately less run_time at high sleep_avg to
2951          * delay them losing their interactive status
2952          */
2953         run_time /= (CURRENT_BONUS(prev) ? : 1);
2954
2955         spin_lock_irq(&rq->lock);
2956
2957         if (unlikely(prev->flags & PF_DEAD))
2958                 prev->state = EXIT_DEAD;
2959
2960         switch_count = &prev->nivcsw;
2961         if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
2962                 switch_count = &prev->nvcsw;
2963                 if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
2964                                 unlikely(signal_pending(prev))))
2965                         prev->state = TASK_RUNNING;
2966                 else {
2967                         if (prev->state == TASK_UNINTERRUPTIBLE)
2968                                 rq->nr_uninterruptible++;
2969                         deactivate_task(prev, rq);
2970                 }
2971         }
2972
2973         cpu = smp_processor_id();
2974         if (unlikely(!rq->nr_running)) {
2975 go_idle:
2976                 idle_balance(cpu, rq);
2977                 if (!rq->nr_running) {
2978                         next = rq->idle;
2979                         rq->expired_timestamp = 0;
2980                         wake_sleeping_dependent(cpu, rq);
2981                         /*
2982                          * wake_sleeping_dependent() might have released
2983                          * the runqueue, so break out if we got new
2984                          * tasks meanwhile:
2985                          */
2986                         if (!rq->nr_running)
2987                                 goto switch_tasks;
2988                 }
2989         } else {
2990                 if (dependent_sleeper(cpu, rq)) {
2991                         next = rq->idle;
2992                         goto switch_tasks;
2993                 }
2994                 /*
2995                  * dependent_sleeper() releases and reacquires the runqueue
2996                  * lock, hence go into the idle loop if the rq went
2997                  * empty meanwhile:
2998                  */
2999                 if (unlikely(!rq->nr_running))
3000                         goto go_idle;
3001         }
3002
3003         array = rq->active;
3004         if (unlikely(!array->nr_active)) {
3005                 /*
3006                  * Switch the active and expired arrays.
3007                  */
3008                 schedstat_inc(rq, sched_switch);
3009                 rq->active = rq->expired;
3010                 rq->expired = array;
3011                 array = rq->active;
3012                 rq->expired_timestamp = 0;
3013                 rq->best_expired_prio = MAX_PRIO;
3014         }
3015
3016         idx = sched_find_first_bit(array->bitmap);
3017         queue = array->queue + idx;
3018         next = list_entry(queue->next, task_t, run_list);
3019
3020         if (!rt_task(next) && interactive_sleep(next->sleep_type)) {
3021                 unsigned long long delta = now - next->timestamp;
3022                 if (unlikely((long long)(now - next->timestamp) < 0))
3023                         delta = 0;
3024
3025                 if (next->sleep_type == SLEEP_INTERACTIVE)
3026                         delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;
3027
3028                 array = next->array;
3029                 new_prio = recalc_task_prio(next, next->timestamp + delta);
3030
3031                 if (unlikely(next->prio != new_prio)) {
3032                         dequeue_task(next, array);
3033                         next->prio = new_prio;
3034                         enqueue_task(next, array);
3035                 }
3036         }
3037         next->sleep_type = SLEEP_NORMAL;
3038 switch_tasks:
3039         if (next == rq->idle)
3040                 schedstat_inc(rq, sched_goidle);
3041         prefetch(next);
3042         prefetch_stack(next);
3043         clear_tsk_need_resched(prev);
3044         rcu_qsctr_inc(task_cpu(prev));
3045
3046         update_cpu_clock(prev, rq, now);
3047
3048         prev->sleep_avg -= run_time;
3049         if ((long)prev->sleep_avg <= 0)
3050                 prev->sleep_avg = 0;
3051         prev->timestamp = prev->last_ran = now;
3052
3053         sched_info_switch(prev, next);
3054         if (likely(prev != next)) {
3055                 next->timestamp = now;
3056                 rq->nr_switches++;
3057                 rq->curr = next;
3058                 ++*switch_count;
3059
3060                 prepare_task_switch(rq, next);
3061                 prev = context_switch(rq, prev, next);
3062                 barrier();
3063                 /*
3064                  * this_rq must be evaluated again because prev may have moved
3065                  * CPUs since it called schedule(), thus the 'rq' on its stack
3066                  * frame will be invalid.
3067                  */
3068                 finish_task_switch(this_rq(), prev);
3069         } else
3070                 spin_unlock_irq(&rq->lock);
3071
3072         prev = current;
3073         if (unlikely(reacquire_kernel_lock(prev) < 0))
3074                 goto need_resched_nonpreemptible;
3075         preempt_enable_no_resched();
3076         if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
3077                 goto need_resched;
3078 }
3079
3080 EXPORT_SYMBOL(schedule);
3081
3082 #ifdef CONFIG_PREEMPT
3083 /*
3084  * this is is the entry point to schedule() from in-kernel preemption
3085  * off of preempt_enable.  Kernel preemptions off return from interrupt
3086  * occur there and call schedule directly.
3087  */
3088 asmlinkage void __sched preempt_schedule(void)
3089 {
3090         struct thread_info *ti = current_thread_info();
3091 #ifdef CONFIG_PREEMPT_BKL
3092         struct task_struct *task = current;
3093         int saved_lock_depth;
3094 #endif
3095         /*
3096          * If there is a non-zero preempt_count or interrupts are disabled,
3097          * we do not want to preempt the current task.  Just return..
3098          */
3099         if (unlikely(ti->preempt_count || irqs_disabled()))
3100                 return;
3101
3102 need_resched:
3103         add_preempt_count(PREEMPT_ACTIVE);
3104         /*
3105          * We keep the big kernel semaphore locked, but we
3106          * clear ->lock_depth so that schedule() doesnt
3107          * auto-release the semaphore:
3108          */
3109 #ifdef CONFIG_PREEMPT_BKL
3110         saved_lock_depth = task->lock_depth;
3111         task->lock_depth = -1;
3112 #endif
3113         schedule();
3114 #ifdef CONFIG_PREEMPT_BKL
3115         task->lock_depth = saved_lock_depth;
3116 #endif
3117         sub_preempt_count(PREEMPT_ACTIVE);
3118
3119         /* we could miss a preemption opportunity between schedule and now */
3120         barrier();
3121         if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
3122                 goto need_resched;
3123 }
3124
3125 EXPORT_SYMBOL(preempt_schedule);
3126
3127 /*
3128  * this is is the entry point to schedule() from kernel preemption
3129  * off of irq context.
3130  * Note, that this is called and return with irqs disabled. This will
3131  * protect us against recursive calling from irq.
3132  */
3133 asmlinkage void __sched preempt_schedule_irq(void)
3134 {
3135         struct thread_info *ti = current_thread_info();
3136 #ifdef CONFIG_PREEMPT_BKL
3137         struct task_struct *task = current;
3138         int saved_lock_depth;
3139 #endif
3140         /* Catch callers which need to be fixed*/
3141         BUG_ON(ti->preempt_count || !irqs_disabled());
3142
3143 need_resched:
3144         add_preempt_count(PREEMPT_ACTIVE);
3145         /*
3146          * We keep the big kernel semaphore locked, but we
3147          * clear ->lock_depth so that schedule() doesnt
3148          * auto-release the semaphore:
3149          */
3150 #ifdef CONFIG_PREEMPT_BKL
3151         saved_lock_depth = task->lock_depth;
3152         task->lock_depth = -1;
3153 #endif
3154         local_irq_enable();
3155         schedule();
3156         local_irq_disable();
3157 #ifdef CONFIG_PREEMPT_BKL
3158         task->lock_depth = saved_lock_depth;
3159 #endif
3160         sub_preempt_count(PREEMPT_ACTIVE);
3161
3162         /* we could miss a preemption opportunity between schedule and now */
3163         barrier();
3164         if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
3165                 goto need_resched;
3166 }
3167
3168 #endif /* CONFIG_PREEMPT */
3169
3170 int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
3171                           void *key)
3172 {
3173         task_t *p = curr->private;
3174         return try_to_wake_up(p, mode, sync);
3175 }
3176
3177 EXPORT_SYMBOL(default_wake_function);
3178
3179 /*
3180  * The core wakeup function.  Non-exclusive wakeups (nr_exclusive == 0) just
3181  * wake everything up.  If it's an exclusive wakeup (nr_exclusive == small +ve
3182  * number) then we wake all the non-exclusive tasks and one exclusive task.
3183  *
3184  * There are circumstances in which we can try to wake a task which has already
3185  * started to run but is not in state TASK_RUNNING.  try_to_wake_up() returns
3186  * zero in this (rare) case, and we handle it by continuing to scan the queue.
3187  */
3188 static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
3189                              int nr_exclusive, int sync, void *key)
3190 {
3191         struct list_head *tmp, *next;
3192
3193         list_for_each_safe(tmp, next, &q->task_list) {
3194                 wait_queue_t *curr;
3195                 unsigned flags;
3196                 curr = list_entry(tmp, wait_queue_t, task_list);
3197                 flags = curr->flags;
3198                 if (curr->func(curr, mode, sync, key) &&
3199                     (flags & WQ_FLAG_EXCLUSIVE) &&
3200                     !--nr_exclusive)
3201                         break;
3202         }
3203 }
3204
3205 /**
3206  * __wake_up - wake up threads blocked on a waitqueue.
3207  * @q: the waitqueue
3208  * @mode: which threads
3209  * @nr_exclusive: how many wake-one or wake-many threads to wake up
3210  * @key: is directly passed to the wakeup function
3211  */
3212 void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode,
3213                         int nr_exclusive, void *key)
3214 {
3215         unsigned long flags;
3216
3217         spin_lock_irqsave(&q->lock, flags);
3218         __wake_up_common(q, mode, nr_exclusive, 0, key);
3219         spin_unlock_irqrestore(&q->lock, flags);
3220 }
3221
3222 EXPORT_SYMBOL(__wake_up);
3223
3224 /*
3225  * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3226  */
3227 void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
3228 {
3229         __wake_up_common(q, mode, 1, 0, NULL);
3230 }
3231
3232 /**
3233  * __wake_up_sync - wake up threads blocked on a waitqueue.
3234  * @q: the waitqueue
3235  * @mode: which threads
3236  * @nr_exclusive: how many wake-one or wake-many threads to wake up
3237  *
3238  * The sync wakeup differs that the waker knows that it will schedule
3239  * away soon, so while the target thread will be woken up, it will not
3240  * be migrated to another CPU - ie. the two threads are 'synchronized'
3241  * with each other. This can prevent needless bouncing between CPUs.
3242  *
3243  * On UP it can prevent extra preemption.
3244  */
3245 void fastcall
3246 __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
3247 {
3248         unsigned long flags;
3249         int sync = 1;
3250
3251         if (unlikely(!q))
3252                 return;
3253
3254         if (unlikely(!nr_exclusive))
3255                 sync = 0;
3256
3257         spin_lock_irqsave(&q->lock, flags);
3258         __wake_up_common(q, mode, nr_exclusive, sync, NULL);
3259         spin_unlock_irqrestore(&q->lock, flags);
3260 }
3261 EXPORT_SYMBOL_GPL(__wake_up_sync);      /* For internal use only */
3262
3263 void fastcall complete(struct completion *x)
3264 {
3265         unsigned long flags;
3266
3267         spin_lock_irqsave(&x->wait.lock, flags);
3268         x->done++;
3269         __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
3270                          1, 0, NULL);
3271         spin_unlock_irqrestore(&x->wait.lock, flags);
3272 }
3273 EXPORT_SYMBOL(complete);
3274
3275 void fastcall complete_all(struct completion *x)
3276 {
3277         unsigned long flags;
3278
3279         spin_lock_irqsave(&x->wait.lock, flags);
3280         x->done += UINT_MAX/2;
3281         __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
3282                          0, 0, NULL);
3283         spin_unlock_irqrestore(&x->wait.lock, flags);
3284 }
3285 EXPORT_SYMBOL(complete_all);
3286
3287 void fastcall __sched wait_for_completion(struct completion *x)
3288 {
3289         might_sleep();
3290         spin_lock_irq(&x->wait.lock);
3291         if (!x->done) {
3292                 DECLARE_WAITQUEUE(wait, current);
3293
3294                 wait.flags |= WQ_FLAG_EXCLUSIVE;
3295                 __add_wait_queue_tail(&x->wait, &wait);
3296                 do {
3297                         __set_current_state(TASK_UNINTERRUPTIBLE);
3298                         spin_unlock_irq(&x->wait.lock);
3299                         schedule();
3300                         spin_lock_irq(&x->wait.lock);
3301                 } while (!x->done);
3302                 __remove_wait_queue(&x->wait, &wait);
3303         }
3304         x->done--;
3305         spin_unlock_irq(&x->wait.lock);
3306 }
3307 EXPORT_SYMBOL(wait_for_completion);
3308
3309 unsigned long fastcall __sched
3310 wait_for_completion_timeout(struct completion *x, unsigned long timeout)
3311 {
3312         might_sleep();
3313
3314         spin_lock_irq(&x->wait.lock);
3315         if (!x->done) {
3316                 DECLARE_WAITQUEUE(wait, current);
3317
3318                 wait.flags |= WQ_FLAG_EXCLUSIVE;
3319                 __add_wait_queue_tail(&x->wait, &wait);
3320                 do {
3321                         __set_current_state(TASK_UNINTERRUPTIBLE);
3322                         spin_unlock_irq(&x->wait.lock);
3323                         timeout = schedule_timeout(timeout);
3324                         spin_lock_irq(&x->wait.lock);
3325                         if (!timeout) {
3326                                 __remove_wait_queue(&x->wait, &wait);
3327                                 goto out;
3328                         }
3329                 } while (!x->done);
3330                 __remove_wait_queue(&x->wait, &wait);
3331         }
3332         x->done--;
3333 out:
3334         spin_unlock_irq(&x->wait.lock);
3335         return timeout;
3336 }
3337 EXPORT_SYMBOL(wait_for_completion_timeout);
3338
3339 int fastcall __sched wait_for_completion_interruptible(struct completion *x)
3340 {
3341         int ret = 0;
3342
3343         might_sleep();
3344
3345         spin_lock_irq(&x->wait.lock);
3346         if (!x->done) {
3347                 DECLARE_WAITQUEUE(wait, current);
3348
3349                 wait.flags |= WQ_FLAG_EXCLUSIVE;
3350                 __add_wait_queue_tail(&x->wait, &wait);
3351                 do {
3352                         if (signal_pending(current)) {
3353                                 ret = -ERESTARTSYS;
3354                                 __remove_wait_queue(&x->wait, &wait);
3355                                 goto out;
3356                         }
3357                         __set_current_state(TASK_INTERRUPTIBLE);
3358                         spin_unlock_irq(&x->wait.lock);
3359                         schedule();
3360                         spin_lock_irq(&x->wait.lock);
3361                 } while (!x->done);
3362                 __remove_wait_queue(&x->wait, &wait);
3363         }
3364         x->done--;
3365 out:
3366         spin_unlock_irq(&x->wait.lock);
3367
3368         return ret;
3369 }
3370 EXPORT_SYMBOL(wait_for_completion_interruptible);
3371
3372 unsigned long fastcall __sched
3373 wait_for_completion_interruptible_timeout(struct completion *x,
3374                                           unsigned long timeout)
3375 {
3376         might_sleep();
3377
3378         spin_lock_irq(&x->wait.lock);
3379         if (!x->done) {
3380                 DECLARE_WAITQUEUE(wait, current);
3381
3382                 wait.flags |= WQ_FLAG_EXCLUSIVE;
3383                 __add_wait_queue_tail(&x->wait, &wait);
3384                 do {
3385                         if (signal_pending(current)) {
3386                                 timeout = -ERESTARTSYS;
3387                                 __remove_wait_queue(&x->wait, &wait);
3388                                 goto out;
3389                         }
3390                         __set_current_state(TASK_INTERRUPTIBLE);
3391                         spin_unlock_irq(&x->wait.lock);
3392                         timeout = schedule_timeout(timeout);
3393                         spin_lock_irq(&x->wait.lock);
3394                         if (!timeout) {
3395                                 __remove_wait_queue(&x->wait, &wait);
3396                                 goto out;
3397                         }
3398                 } while (!x->done);
3399                 __remove_wait_queue(&x->wait, &wait);
3400         }
3401         x->done--;
3402 out:
3403         spin_unlock_irq(&x->wait.lock);
3404         return timeout;
3405 }
3406 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
3407
3408
3409 #define SLEEP_ON_VAR                                    \
3410         unsigned long flags;                            \
3411         wait_queue_t wait;                              \
3412         init_waitqueue_entry(&wait, current);
3413
3414 #define SLEEP_ON_HEAD                                   \
3415         spin_lock_irqsave(&q->lock,flags);              \
3416         __add_wait_queue(q, &wait);                     \
3417         spin_unlock(&q->lock);
3418
3419 #define SLEEP_ON_TAIL                                   \
3420         spin_lock_irq(&q->lock);                        \
3421         __remove_wait_queue(q, &wait);                  \
3422         spin_unlock_irqrestore(&q->lock, flags);
3423
3424 void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q)
3425 {
3426         SLEEP_ON_VAR
3427
3428         current->state = TASK_INTERRUPTIBLE;
3429
3430         SLEEP_ON_HEAD
3431         schedule();
3432         SLEEP_ON_TAIL
3433 }
3434
3435 EXPORT_SYMBOL(interruptible_sleep_on);
3436
3437 long fastcall __sched
3438 interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
3439 {
3440         SLEEP_ON_VAR
3441
3442         current->state = TASK_INTERRUPTIBLE;
3443
3444         SLEEP_ON_HEAD
3445         timeout = schedule_timeout(timeout);
3446         SLEEP_ON_TAIL
3447
3448         return timeout;
3449 }
3450
3451 EXPORT_SYMBOL(interruptible_sleep_on_timeout);
3452
3453 void fastcall __sched sleep_on(wait_queue_head_t *q)
3454 {
3455         SLEEP_ON_VAR
3456
3457         current->state = TASK_UNINTERRUPTIBLE;
3458
3459         SLEEP_ON_HEAD
3460         schedule();
3461         SLEEP_ON_TAIL
3462 }
3463
3464 EXPORT_SYMBOL(sleep_on);
3465
3466 long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
3467 {
3468         SLEEP_ON_VAR
3469
3470         current->state = TASK_UNINTERRUPTIBLE;
3471
3472         SLEEP_ON_HEAD
3473         timeout = schedule_timeout(timeout);
3474         SLEEP_ON_TAIL
3475
3476         return timeout;
3477 }
3478
3479 EXPORT_SYMBOL(sleep_on_timeout);
3480
3481 void set_user_nice(task_t *p, long nice)
3482 {
3483         unsigned long flags;
3484         prio_array_t *array;
3485         runqueue_t *rq;
3486         int old_prio, new_prio, delta;
3487
3488         if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
3489                 return;
3490         /*
3491          * We have to be careful, if called from sys_setpriority(),
3492          * the task might be in the middle of scheduling on another CPU.
3493          */
3494         rq = task_rq_lock(p, &flags);
3495         /*
3496          * The RT priorities are set via sched_setscheduler(), but we still
3497          * allow the 'normal' nice value to be set - but as expected
3498          * it wont have any effect on scheduling until the task is
3499          * not SCHED_NORMAL/SCHED_BATCH:
3500          */
3501         if (rt_task(p)) {
3502                 p->static_prio = NICE_TO_PRIO(nice);
3503                 goto out_unlock;
3504         }
3505         array = p->array;
3506         if (array)
3507                 dequeue_task(p, array);
3508
3509         old_prio = p->prio;
3510         new_prio = NICE_TO_PRIO(nice);
3511         delta = new_prio - old_prio;
3512         p->static_prio = NICE_TO_PRIO(nice);
3513         p->prio += delta;
3514
3515         if (array) {<