kernel/sched.c

/* */
This source file includes following definitions.
add_to_runqueue
del_from_runqueue
move_last_runqueue
wake_up_process
process_timeout
goodness
schedule
sys_pause
wake_up
wake_up_interruptible
__down
__sleep_on
interruptible_sleep_on
sleep_on
add_timer
del_timer
run_timer_list
run_old_timers
tqueue_bh
immediate_bh
count_active_tasks
calc_load
second_overflow
update_wall_time_one_tick
update_wall_time
do_process_times
do_it_virt
do_it_prof
update_one_process
update_process_times
timer_bh
do_timer
sys_alarm
sys_getpid
sys_getppid
sys_getuid
sys_geteuid
sys_getgid
sys_getegid
sys_nice
find_process_by_pid
setscheduler
sys_sched_setscheduler
sys_sched_setparam
sys_sched_getscheduler
sys_sched_getparam
sys_sched_yield
sys_sched_get_priority_max
sys_sched_get_priority_min
sys_sched_rr_get_interval
timespectojiffies
jiffiestotimespec
sys_nanosleep
show_task
show_state
sched_init
   1 /*
   2  *  linux/kernel/sched.c
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6 
   7 /*
   8  * 'sched.c' is the main kernel file. It contains scheduling primitives
   9  * (sleep_on, wakeup, schedule etc) as well as a number of simple system
  10  * call functions (type getpid()), which just extract a field from
  11  * current-task
  12  */
  13 
  14 #include <linux/signal.h>
  15 #include <linux/sched.h>
  16 #include <linux/timer.h>
  17 #include <linux/kernel.h>
  18 #include <linux/kernel_stat.h>
  19 #include <linux/fdreg.h>
  20 #include <linux/errno.h>
  21 #include <linux/time.h>
  22 #include <linux/ptrace.h>
  23 #include <linux/delay.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/tqueue.h>
  26 #include <linux/resource.h>
  27 #include <linux/mm.h>
  28 #include <linux/smp.h>
  29 
  30 #include <asm/system.h>
  31 #include <asm/io.h>
  32 #include <asm/segment.h>
  33 #include <asm/pgtable.h>
  34 #include <asm/mmu_context.h>
  35 
  36 #include <linux/timex.h>
  37 
  38 /*
  39  * kernel variables
  40  */
  41 
  42 int securelevel = 0;                    /* system security level */
  43 
  44 long tick = 1000000 / HZ;               /* timer interrupt period */
  45 volatile struct timeval xtime;          /* The current time */
  46 int tickadj = 500/HZ;                   /* microsecs */
  47 
  48 DECLARE_TASK_QUEUE(tq_timer);
  49 DECLARE_TASK_QUEUE(tq_immediate);
  50 DECLARE_TASK_QUEUE(tq_scheduler);
  51 
  52 /*
  53  * phase-lock loop variables
  54  */
  55 int time_state = TIME_BAD;      /* clock synchronization status */
  56 int time_status = STA_UNSYNC | STA_PLL; /* clock status bits */
  57 long time_offset = 0;           /* time adjustment (us) */
  58 long time_constant = 2;         /* pll time constant */
  59 long time_tolerance = MAXFREQ;  /* frequency tolerance (ppm) */
  60 long time_precision = 1;        /* clock precision (us) */
  61 long time_maxerror = 0x70000000;/* maximum error */
  62 long time_esterror = 0x70000000;/* estimated error */
  63 long time_phase = 0;            /* phase offset (scaled us) */
  64 long time_freq = 0;             /* frequency offset (scaled ppm) */
  65 long time_adj = 0;              /* tick adjust (scaled 1 / HZ) */
  66 long time_reftime = 0;          /* time at last adjustment (s) */
  67 
  68 long time_adjust = 0;
  69 long time_adjust_step = 0;
  70 
  71 int need_resched = 0;
  72 unsigned long event = 0;
  73 
  74 extern int _setitimer(int, struct itimerval *, struct itimerval *);
  75 unsigned int * prof_buffer = NULL;
  76 unsigned long prof_len = 0;
  77 unsigned long prof_shift = 0;
  78 
  79 #define _S(nr) (1<<((nr)-1))
  80 
  81 extern void mem_use(void);
  82 
  83 static unsigned long init_kernel_stack[1024] = { STACK_MAGIC, };
  84 unsigned long init_user_stack[1024] = { STACK_MAGIC, };
  85 static struct vm_area_struct init_mmap = INIT_MMAP;
  86 static struct fs_struct init_fs = INIT_FS;
  87 static struct files_struct init_files = INIT_FILES;
  88 static struct signal_struct init_signals = INIT_SIGNALS;
  89 
  90 struct mm_struct init_mm = INIT_MM;
  91 struct task_struct init_task = INIT_TASK;
  92 
  93 unsigned long volatile jiffies=0;
  94 
  95 struct task_struct *current_set[NR_CPUS];
  96 struct task_struct *last_task_used_math = NULL;
  97 
  98 struct task_struct * task[NR_TASKS] = {&init_task, };
  99 
 100 struct kernel_stat kstat = { 0 };
 101 
 102 static inline void add_to_runqueue(struct task_struct * p)
     /*  */
 103 {
 104 #ifdef __SMP__
 105         int cpu=smp_processor_id();
 106 #endif  
 107 #if 1   /* sanity tests */
 108         if (p->next_run || p->prev_run) {
 109                 printk("task already on run-queue\n");
 110                 return;
 111         }
 112 #endif
 113         if (p->counter > current->counter + 3)
 114                 need_resched = 1;
 115         nr_running++;
 116         (p->prev_run = init_task.prev_run)->next_run = p;
 117         p->next_run = &init_task;
 118         init_task.prev_run = p;
 119 #ifdef __SMP__
 120         /* this is safe only if called with cli()*/
 121         while(set_bit(31,&smp_process_available));
 122 #if 0   
 123         {
 124                 while(test_bit(31,&smp_process_available))
 125                 {
 126                         if(clear_bit(cpu,&smp_invalidate_needed))
 127                         {
 128                                 local_flush_tlb();
 129                                 set_bit(cpu,&cpu_callin_map[0]);
 130                         }
 131                 }
 132         }
 133 #endif  
 134         smp_process_available++;
 135         clear_bit(31,&smp_process_available);
 136         if ((0!=p->pid) && smp_threads_ready)
 137         {
 138                 int i;
 139                 for (i=0;i<smp_num_cpus;i++)
 140                 {
 141                         if (0==current_set[cpu_logical_map[i]]->pid) 
 142                         {
 143                                 smp_message_pass(cpu_logical_map[i], MSG_RESCHEDULE, 0L, 0);
 144                                 break;
 145                         }
 146                 }
 147         }
 148 #endif
 149 }
 150 
 151 static inline void del_from_runqueue(struct task_struct * p)
     /*  */
 152 {
 153         struct task_struct *next = p->next_run;
 154         struct task_struct *prev = p->prev_run;
 155 
 156 #if 1   /* sanity tests */
 157         if (!next || !prev) {
 158                 printk("task not on run-queue\n");
 159                 return;
 160         }
 161 #endif
 162         if (p == &init_task) {
 163                 static int nr = 0;
 164                 if (nr < 5) {
 165                         nr++;
 166                         printk("idle task may not sleep\n");
 167                 }
 168                 return;
 169         }
 170         nr_running--;
 171         next->prev_run = prev;
 172         prev->next_run = next;
 173         p->next_run = NULL;
 174         p->prev_run = NULL;
 175 }
 176 
 177 static inline void move_last_runqueue(struct task_struct * p)
     /*  */
 178 {
 179         struct task_struct *next = p->next_run;
 180         struct task_struct *prev = p->prev_run;
 181 
 182         next->prev_run = prev;
 183         prev->next_run = next;
 184         (p->prev_run = init_task.prev_run)->next_run = p;
 185         p->next_run = &init_task;
 186         init_task.prev_run = p;
 187 }
 188 
 189 /*
 190  * Wake up a process. Put it on the run-queue if it's not
 191  * already there.  The "current" process is always on the
 192  * run-queue (except when the actual re-schedule is in
 193  * progress), and as such you're allowed to do the simpler
 194  * "current->state = TASK_RUNNING" to mark yourself runnable
 195  * without the overhead of this.
 196  */
 197 inline void wake_up_process(struct task_struct * p)
     /*  */
 198 {
 199         unsigned long flags;
 200 
 201         save_flags(flags);
 202         cli();
 203         p->state = TASK_RUNNING;
 204         if (!p->next_run)
 205                 add_to_runqueue(p);
 206         restore_flags(flags);
 207 }
 208 
 209 static void process_timeout(unsigned long __data)
     /*  */
 210 {
 211         struct task_struct * p = (struct task_struct *) __data;
 212 
 213         p->timeout = 0;
 214         wake_up_process(p);
 215 }
 216 
 217 /*
 218  * This is the function that decides how desireable a process is..
 219  * You can weigh different processes against each other depending
 220  * on what CPU they've run on lately etc to try to handle cache
 221  * and TLB miss penalties.
 222  *
 223  * Return values:
 224  *       -1000: never select this
 225  *           0: out of time, recalculate counters (but it might still be
 226  *              selected)
 227  *         +ve: "goodness" value (the larger, the better)
 228  *       +1000: realtime process, select this.
 229  */
 230 static inline int goodness(struct task_struct * p, struct task_struct * prev, int this_cpu)
     /*  */
 231 {
 232         int weight;
 233 
 234 #ifdef __SMP__  
 235         /* We are not permitted to run a task someone else is running */
 236         if (p->processor != NO_PROC_ID)
 237                 return -1000;
 238 #endif
 239 
 240         /*
 241          * Realtime process, select the first one on the
 242          * runqueue (taking priorities within processes
 243          * into account).
 244          */
 245         if (p->policy != SCHED_OTHER)
 246                 return 1000 + p->rt_priority;
 247 
 248         /*
 249          * Give the process a first-approximation goodness value
 250          * according to the number of clock-ticks it has left.
 251          *
 252          * Don't do any other calculations if the time slice is
 253          * over..
 254          */
 255         weight = p->counter;
 256         if (weight) {
 257                         
 258 #ifdef __SMP__
 259                 /* Give a largish advantage to the same processor...   */
 260                 /* (this is equivalent to penalizing other processors) */
 261                 if (p->last_processor == this_cpu)
 262                         weight += PROC_CHANGE_PENALTY;
 263 #endif
 264 
 265                 /* .. and a slight advantage to the current process */
 266                 if (p == prev)
 267                         weight += 1;
 268         }
 269 
 270         return weight;
 271 }
 272 
 273 /*
 274  *  'schedule()' is the scheduler function. It's a very simple and nice
 275  * scheduler: it's not perfect, but certainly works for most things.
 276  *
 277  * The goto is "interesting".
 278  *
 279  *   NOTE!!  Task 0 is the 'idle' task, which gets called when no other
 280  * tasks can run. It can not be killed, and it cannot sleep. The 'state'
 281  * information in task[0] is never used.
 282  */
 283 asmlinkage void schedule(void)
     /*  */
 284 {
 285         int c;
 286         struct task_struct * p;
 287         struct task_struct * prev, * next;
 288         unsigned long timeout = 0;
 289         int this_cpu=smp_processor_id();
 290 
 291 /* check alarm, wake up any interruptible tasks that have got a signal */
 292 
 293         if (intr_count)
 294                 goto scheduling_in_interrupt;
 295 
 296         if (bh_active & bh_mask) {
 297                 intr_count = 1;
 298                 do_bottom_half();
 299                 intr_count = 0;
 300         }
 301 
 302         run_task_queue(&tq_scheduler);
 303 
 304         need_resched = 0;
 305         prev = current;
 306         cli();
 307         /* move an exhausted RR process to be last.. */
 308         if (!prev->counter && prev->policy == SCHED_RR) {
 309                 prev->counter = prev->priority;
 310                 move_last_runqueue(prev);
 311         }
 312         switch (prev->state) {
 313                 case TASK_INTERRUPTIBLE:
 314                         if (prev->signal & ~prev->blocked)
 315                                 goto makerunnable;
 316                         timeout = prev->timeout;
 317                         if (timeout && (timeout <= jiffies)) {
 318                                 prev->timeout = 0;
 319                                 timeout = 0;
 320                 makerunnable:
 321                                 prev->state = TASK_RUNNING;
 322                                 break;
 323                         }
 324                 default:
 325                         del_from_runqueue(prev);
 326                 case TASK_RUNNING:
 327         }
 328         p = init_task.next_run;
 329         sti();
 330         
 331 #ifdef __SMP__
 332         /*
 333          *      This is safe as we do not permit re-entry of schedule()
 334          */
 335         prev->processor = NO_PROC_ID;   
 336 #endif  
 337 
 338 /*
 339  * Note! there may appear new tasks on the run-queue during this, as
 340  * interrupts are enabled. However, they will be put on front of the
 341  * list, so our list starting at "p" is essentially fixed.
 342  */
 343 /* this is the scheduler proper: */
 344         c = -1000;
 345         next = &init_task;
 346         while (p != &init_task) {
 347                 int weight = goodness(p, prev, this_cpu);
 348                 if (weight > c)
 349                         c = weight, next = p;
 350                 p = p->next_run;
 351         }
 352 
 353         /* if all runnable processes have "counter == 0", re-calculate counters */
 354         if (!c) {
 355                 for_each_task(p)
 356                         p->counter = (p->counter >> 1) + p->priority;
 357         }
 358 #ifdef __SMP__  
 359         
 360         /*
 361          *      Context switching between two idle threads is pointless.
 362          */
 363         if(!prev->pid && !next->pid)
 364                 next=prev;
 365         /*
 366          *      Allocate process to CPU
 367          */
 368          
 369          next->processor = this_cpu;
 370          next->last_processor = this_cpu;
 371          
 372 #endif   
 373 #ifdef __SMP_PROF__ 
 374         /* mark processor running an idle thread */
 375         if (0==next->pid)
 376                 set_bit(this_cpu,&smp_idle_map);
 377         else
 378                 clear_bit(this_cpu,&smp_idle_map);
 379 #endif
 380         if (prev != next) {
 381                 struct timer_list timer;
 382 
 383                 kstat.context_swtch++;
 384                 if (timeout) {
 385                         init_timer(&timer);
 386                         timer.expires = timeout;
 387                         timer.data = (unsigned long) prev;
 388                         timer.function = process_timeout;
 389                         add_timer(&timer);
 390                 }
 391                 get_mmu_context(next);
 392                 switch_to(prev,next);
 393                 if (timeout)
 394                         del_timer(&timer);
 395         }
 396         return;
 397 
 398 scheduling_in_interrupt:
 399         printk("Aiee: scheduling in interrupt\n");
 400 }
 401 
 402 #ifndef __alpha__
 403 
 404 /*
 405  * For backwards compatibility?  This can be done in libc so Alpha
 406  * and all newer ports shouldn't need it.
 407  */
 408 asmlinkage int sys_pause(void)
     /*  */
 409 {
 410         current->state = TASK_INTERRUPTIBLE;
 411         schedule();
 412         return -ERESTARTNOHAND;
 413 }
 414 
 415 #endif
 416 
 417 /*
 418  * wake_up doesn't wake up stopped processes - they have to be awakened
 419  * with signals or similar.
 420  *
 421  * Note that this doesn't need cli-sti pairs: interrupts may not change
 422  * the wait-queue structures directly, but only call wake_up() to wake
 423  * a process. The process itself must remove the queue once it has woken.
 424  */
 425 void wake_up(struct wait_queue **q)
     /*  */
 426 {
 427         struct wait_queue *tmp;
 428         struct task_struct * p;
 429 
 430         if (!q || !(tmp = *q))
 431                 return;
 432         do {
 433                 if ((p = tmp->task) != NULL) {
 434                         if ((p->state == TASK_UNINTERRUPTIBLE) ||
 435                             (p->state == TASK_INTERRUPTIBLE))
 436                                 wake_up_process(p);
 437                 }
 438                 if (!tmp->next) {
 439                         printk("wait_queue is bad (eip = %p)\n",
 440                                 __builtin_return_address(0));
 441                         printk("        q = %p\n",q);
 442                         printk("       *q = %p\n",*q);
 443                         printk("      tmp = %p\n",tmp);
 444                         break;
 445                 }
 446                 tmp = tmp->next;
 447         } while (tmp != *q);
 448 }
 449 
 450 void wake_up_interruptible(struct wait_queue **q)
     /*  */
 451 {
 452         struct wait_queue *tmp;
 453         struct task_struct * p;
 454 
 455         if (!q || !(tmp = *q))
 456                 return;
 457         do {
 458                 if ((p = tmp->task) != NULL) {
 459                         if (p->state == TASK_INTERRUPTIBLE)
 460                                 wake_up_process(p);
 461                 }
 462                 if (!tmp->next) {
 463                         printk("wait_queue is bad (eip = %p)\n",
 464                                 __builtin_return_address(0));
 465                         printk("        q = %p\n",q);
 466                         printk("       *q = %p\n",*q);
 467                         printk("      tmp = %p\n",tmp);
 468                         break;
 469                 }
 470                 tmp = tmp->next;
 471         } while (tmp != *q);
 472 }
 473 
 474 void __down(struct semaphore * sem)
     /*  */
 475 {
 476         struct wait_queue wait = { current, NULL };
 477         add_wait_queue(&sem->wait, &wait);
 478         current->state = TASK_UNINTERRUPTIBLE;
 479         while (sem->count <= 0) {
 480                 schedule();
 481                 current->state = TASK_UNINTERRUPTIBLE;
 482         }
 483         current->state = TASK_RUNNING;
 484         remove_wait_queue(&sem->wait, &wait);
 485 }
 486 
 487 static inline void __sleep_on(struct wait_queue **p, int state)
     /*  */
 488 {
 489         unsigned long flags;
 490         struct wait_queue wait = { current, NULL };
 491 
 492         if (!p)
 493                 return;
 494         if (current == task[0])
 495                 panic("task[0] trying to sleep");
 496         current->state = state;
 497         add_wait_queue(p, &wait);
 498         save_flags(flags);
 499         sti();
 500         schedule();
 501         remove_wait_queue(p, &wait);
 502         restore_flags(flags);
 503 }
 504 
 505 void interruptible_sleep_on(struct wait_queue **p)
     /*  */
 506 {
 507         __sleep_on(p,TASK_INTERRUPTIBLE);
 508 }
 509 
 510 void sleep_on(struct wait_queue **p)
     /*  */
 511 {
 512         __sleep_on(p,TASK_UNINTERRUPTIBLE);
 513 }
 514 
 515 /*
 516  * The head for the timer-list has a "expires" field of MAX_UINT,
 517  * and the sorting routine counts on this..
 518  */
 519 static struct timer_list timer_head = { &timer_head, &timer_head, ~0, 0, NULL };
 520 #define SLOW_BUT_DEBUGGING_TIMERS 0
 521 
 522 void add_timer(struct timer_list * timer)
     /*  */
 523 {
 524         unsigned long flags;
 525         struct timer_list *p;
 526 
 527 #if SLOW_BUT_DEBUGGING_TIMERS
 528         if (timer->next || timer->prev) {
 529                 printk("add_timer() called with non-zero list from %p\n",
 530                         __builtin_return_address(0));
 531                 return;
 532         }
 533 #endif
 534         p = &timer_head;
 535         save_flags(flags);
 536         cli();
 537         do {
 538                 p = p->next;
 539         } while (timer->expires > p->expires);
 540         timer->next = p;
 541         timer->prev = p->prev;
 542         p->prev = timer;
 543         timer->prev->next = timer;
 544         restore_flags(flags);
 545 }
 546 
 547 int del_timer(struct timer_list * timer)
     /*  */
 548 {
 549         unsigned long flags;
 550 #if SLOW_BUT_DEBUGGING_TIMERS
 551         struct timer_list * p;
 552 
 553         p = &timer_head;
 554         save_flags(flags);
 555         cli();
 556         while ((p = p->next) != &timer_head) {
 557                 if (p == timer) {
 558                         timer->next->prev = timer->prev;
 559                         timer->prev->next = timer->next;
 560                         timer->next = timer->prev = NULL;
 561                         restore_flags(flags);
 562                         return 1;
 563                 }
 564         }
 565         if (timer->next || timer->prev)
 566                 printk("del_timer() called from %p with timer not initialized\n",
 567                         __builtin_return_address(0));
 568         restore_flags(flags);
 569         return 0;
 570 #else
 571         struct timer_list * next;
 572         int ret = 0;
 573         save_flags(flags);
 574         cli();
 575         if ((next = timer->next) != NULL) {
 576                 (next->prev = timer->prev)->next = next;
 577                 timer->next = timer->prev = NULL;
 578                 ret = 1;
 579         }
 580         restore_flags(flags);
 581         return ret;
 582 #endif
 583 }
 584 
 585 static inline void run_timer_list(void)
     /*  */
 586 {
 587         struct timer_list * timer;
 588 
 589         while ((timer = timer_head.next) != &timer_head && timer->expires <= jiffies) {
 590                 void (*fn)(unsigned long) = timer->function;
 591                 unsigned long data = timer->data;
 592                 timer->next->prev = timer->prev;
 593                 timer->prev->next = timer->next;
 594                 timer->next = timer->prev = NULL;
 595                 sti();
 596                 fn(data);
 597                 cli();
 598         }
 599 }
 600 
 601 static inline void run_old_timers(void)
     /*  */
 602 {
 603         struct timer_struct *tp;
 604         unsigned long mask;
 605 
 606         for (mask = 1, tp = timer_table+0 ; mask ; tp++,mask += mask) {
 607                 if (mask > timer_active)
 608                         break;
 609                 if (!(mask & timer_active))
 610                         continue;
 611                 if (tp->expires > jiffies)
 612                         continue;
 613                 timer_active &= ~mask;
 614                 tp->fn();
 615                 sti();
 616         }
 617 }
 618 
 619 void tqueue_bh(void)
     /*  */
 620 {
 621         run_task_queue(&tq_timer);
 622 }
 623 
 624 void immediate_bh(void)
     /*  */
 625 {
 626         run_task_queue(&tq_immediate);
 627 }
 628 
 629 unsigned long timer_active = 0;
 630 struct timer_struct timer_table[32];
 631 
 632 /*
 633  * Hmm.. Changed this, as the GNU make sources (load.c) seems to
 634  * imply that avenrun[] is the standard name for this kind of thing.
 635  * Nothing else seems to be standardized: the fractional size etc
 636  * all seem to differ on different machines.
 637  */
 638 unsigned long avenrun[3] = { 0,0,0 };
 639 
 640 /*
 641  * Nr of active tasks - counted in fixed-point numbers
 642  */
 643 static unsigned long count_active_tasks(void)
     /*  */
 644 {
 645         struct task_struct **p;
 646         unsigned long nr = 0;
 647 
 648         for(p = &LAST_TASK; p > &FIRST_TASK; --p)
 649                 if (*p && ((*p)->state == TASK_RUNNING ||
 650                            (*p)->state == TASK_UNINTERRUPTIBLE ||
 651                            (*p)->state == TASK_SWAPPING))
 652                         nr += FIXED_1;
 653 #ifdef __SMP__
 654         nr-=(smp_num_cpus-1)*FIXED_1;
 655 #endif                  
 656         return nr;
 657 }
 658 
 659 static inline void calc_load(unsigned long ticks)
     /*  */
 660 {
 661         unsigned long active_tasks; /* fixed-point */
 662         static int count = LOAD_FREQ;
 663 
 664         count -= ticks;
 665         if (count < 0) {
 666                 count += LOAD_FREQ;
 667                 active_tasks = count_active_tasks();
 668                 CALC_LOAD(avenrun[0], EXP_1, active_tasks);
 669                 CALC_LOAD(avenrun[1], EXP_5, active_tasks);
 670                 CALC_LOAD(avenrun[2], EXP_15, active_tasks);
 671         }
 672 }
 673 
 674 /*
 675  * this routine handles the overflow of the microsecond field
 676  *
 677  * The tricky bits of code to handle the accurate clock support
 678  * were provided by Dave Mills (Mills@UDEL.EDU) of NTP fame.
 679  * They were originally developed for SUN and DEC kernels.
 680  * All the kudos should go to Dave for this stuff.
 681  *
 682  */
 683 static void second_overflow(void)
     /*  */
 684 {
 685     long ltemp;
 686 
 687     /* Bump the maxerror field */
 688     time_maxerror = (0x70000000-time_maxerror <
 689                      time_tolerance >> SHIFT_USEC) ?
 690         0x70000000 : (time_maxerror + (time_tolerance >> SHIFT_USEC));
 691 
 692     /*
 693      * Leap second processing. If in leap-insert state at
 694      * the end of the day, the system clock is set back one
 695      * second; if in leap-delete state, the system clock is
 696      * set ahead one second. The microtime() routine or
 697      * external clock driver will insure that reported time
 698      * is always monotonic. The ugly divides should be
 699      * replaced.
 700      */
 701     switch (time_state) {
 702 
 703     case TIME_OK:
 704         if (time_status & STA_INS)
 705             time_state = TIME_INS;
 706         else if (time_status & STA_DEL)
 707             time_state = TIME_DEL;
 708         break;
 709 
 710     case TIME_INS:
 711         if (xtime.tv_sec % 86400 == 0) {
 712             xtime.tv_sec--;
 713             time_state = TIME_OOP;
 714             printk("Clock: inserting leap second 23:59:60 UTC\n");
 715         }
 716         break;
 717 
 718     case TIME_DEL:
 719         if ((xtime.tv_sec + 1) % 86400 == 0) {
 720             xtime.tv_sec++;
 721             time_state = TIME_WAIT;
 722             printk("Clock: deleting leap second 23:59:59 UTC\n");
 723         }
 724         break;
 725 
 726     case TIME_OOP:
 727 
 728         time_state = TIME_WAIT;
 729         break;
 730 
 731     case TIME_WAIT:
 732         if (!(time_status & (STA_INS | STA_DEL)))
 733             time_state = TIME_OK;
 734     }
 735 
 736     /*
 737      * Compute the phase adjustment for the next second. In
 738      * PLL mode, the offset is reduced by a fixed factor
 739      * times the time constant. In FLL mode the offset is
 740      * used directly. In either mode, the maximum phase
 741      * adjustment for each second is clamped so as to spread
 742      * the adjustment over not more than the number of
 743      * seconds between updates.
 744      */
 745     if (time_offset < 0) {
 746         ltemp = -time_offset;
 747         if (!(time_status & STA_FLL))
 748             ltemp >>= SHIFT_KG + time_constant;
 749         if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
 750             ltemp = (MAXPHASE / MINSEC) <<
 751                 SHIFT_UPDATE;
 752         time_offset += ltemp;
 753         time_adj = -ltemp << (SHIFT_SCALE - SHIFT_HZ -
 754                               SHIFT_UPDATE);
 755     } else {
 756         ltemp = time_offset;
 757         if (!(time_status & STA_FLL))
 758             ltemp >>= SHIFT_KG + time_constant;
 759         if (ltemp > (MAXPHASE / MINSEC) << SHIFT_UPDATE)
 760             ltemp = (MAXPHASE / MINSEC) <<
 761                 SHIFT_UPDATE;
 762         time_offset -= ltemp;
 763         time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ -
 764                              SHIFT_UPDATE);
 765     }
 766 
 767     /*
 768      * Compute the frequency estimate and additional phase
 769      * adjustment due to frequency error for the next
 770      * second. When the PPS signal is engaged, gnaw on the
 771      * watchdog counter and update the frequency computed by
 772      * the pll and the PPS signal.
 773      */
 774     pps_valid++;
 775     if (pps_valid == PPS_VALID) {
 776         pps_jitter = MAXTIME;
 777         pps_stabil = MAXFREQ;
 778         time_status &= ~(STA_PPSSIGNAL | STA_PPSJITTER |
 779                          STA_PPSWANDER | STA_PPSERROR);
 780     }
 781     ltemp = time_freq + pps_freq;
 782     if (ltemp < 0)
 783         time_adj -= -ltemp >>
 784             (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
 785     else
 786         time_adj += ltemp >>
 787             (SHIFT_USEC + SHIFT_HZ - SHIFT_SCALE);
 788 
 789 #if HZ == 100
 790     /* compensate for (HZ==100) != 128. Add 25% to get 125; => only 3% error */
 791     if (time_adj < 0)
 792         time_adj -= -time_adj >> 2;
 793     else
 794         time_adj += time_adj >> 2;
 795 #endif
 796 }
 797 
 798 static void update_wall_time_one_tick(void)
     /*  */
 799 {
 800         /*
 801          * Advance the phase, once it gets to one microsecond, then
 802          * advance the tick more.
 803          */
 804         time_phase += time_adj;
 805         if (time_phase <= -FINEUSEC) {
 806                 long ltemp = -time_phase >> SHIFT_SCALE;
 807                 time_phase += ltemp << SHIFT_SCALE;
 808                 xtime.tv_usec += tick + time_adjust_step - ltemp;
 809         }
 810         else if (time_phase >= FINEUSEC) {
 811                 long ltemp = time_phase >> SHIFT_SCALE;
 812                 time_phase -= ltemp << SHIFT_SCALE;
 813                 xtime.tv_usec += tick + time_adjust_step + ltemp;
 814         } else
 815                 xtime.tv_usec += tick + time_adjust_step;
 816 
 817         if (time_adjust) {
 818             /* We are doing an adjtime thing. 
 819              *
 820              * Modify the value of the tick for next time.
 821              * Note that a positive delta means we want the clock
 822              * to run fast. This means that the tick should be bigger
 823              *
 824              * Limit the amount of the step for *next* tick to be
 825              * in the range -tickadj .. +tickadj
 826              */
 827              if (time_adjust > tickadj)
 828                 time_adjust_step = tickadj;
 829              else if (time_adjust < -tickadj)
 830                 time_adjust_step = -tickadj;
 831              else
 832                 time_adjust_step = time_adjust;
 833              
 834             /* Reduce by this step the amount of time left  */
 835             time_adjust -= time_adjust_step;
 836         }
 837         else
 838             time_adjust_step = 0;
 839 }
 840 
 841 /*
 842  * Using a loop looks inefficient, but "ticks" is
 843  * usually just one (we shouldn't be losing ticks,
 844  * we're doing this this way mainly for interrupt
 845  * latency reasons, not because we think we'll
 846  * have lots of lost timer ticks
 847  */
 848 static void update_wall_time(unsigned long ticks)
     /*  */
 849 {
 850         do {
 851                 ticks--;
 852                 update_wall_time_one_tick();
 853         } while (ticks);
 854 
 855         if (xtime.tv_usec >= 1000000) {
 856             xtime.tv_usec -= 1000000;
 857             xtime.tv_sec++;
 858             second_overflow();
 859         }
 860 }
 861 
 862 static inline void do_process_times(struct task_struct *p,
     /*  */
 863         unsigned long user, unsigned long system)
 864 {
 865         long psecs;
 866 
 867         p->utime += user;
 868         p->stime += system;
 869 
 870         psecs = (p->stime + p->utime) / HZ;
 871         if (psecs > p->rlim[RLIMIT_CPU].rlim_cur) {
 872                 /* Send SIGXCPU every second.. */
 873                 if (psecs * HZ == p->stime + p->utime)
 874                         send_sig(SIGXCPU, p, 1);
 875                 /* and SIGKILL when we go over max.. */
 876                 if (psecs > p->rlim[RLIMIT_CPU].rlim_max)
 877                         send_sig(SIGKILL, p, 1);
 878         }
 879 }
 880 
 881 static inline void do_it_virt(struct task_struct * p, unsigned long ticks)
     /*  */
 882 {
 883         unsigned long it_virt = p->it_virt_value;
 884 
 885         if (it_virt) {
 886                 if (it_virt <= ticks) {
 887                         it_virt = ticks + p->it_virt_incr;
 888                         send_sig(SIGVTALRM, p, 1);
 889                 }
 890                 p->it_virt_value = it_virt - ticks;
 891         }
 892 }
 893 
 894 static inline void do_it_prof(struct task_struct * p, unsigned long ticks)
     /*  */
 895 {
 896         unsigned long it_prof = p->it_prof_value;
 897 
 898         if (it_prof) {
 899                 if (it_prof <= ticks) {
 900                         it_prof = ticks + p->it_prof_incr;
 901                         send_sig(SIGPROF, p, 1);
 902                 }
 903                 p->it_prof_value = it_prof - ticks;
 904         }
 905 }
 906 
 907 static __inline__ void update_one_process(struct task_struct *p,
     /*  */
 908         unsigned long ticks, unsigned long user, unsigned long system)
 909 {
 910         do_process_times(p, user, system);
 911         do_it_virt(p, user);
 912         do_it_prof(p, ticks);
 913 }       
 914 
 915 static void update_process_times(unsigned long ticks, unsigned long system)
     /*  */
 916 {
 917 #ifndef  __SMP__
 918         struct task_struct * p = current;
 919         unsigned long user = ticks - system;
 920         if (p->pid) {
 921                 p->counter -= ticks;
 922                 if (p->counter < 0) {
 923                         p->counter = 0;
 924                         need_resched = 1;
 925                 }
 926                 if (p->priority < DEF_PRIORITY)
 927                         kstat.cpu_nice += user;
 928                 else
 929                         kstat.cpu_user += user;
 930                 kstat.cpu_system += system;
 931         }
 932         update_one_process(p, ticks, user, system);
 933 #else
 934         int cpu,j;
 935         cpu = smp_processor_id();
 936         for (j=0;j<smp_num_cpus;j++)
 937         {
 938                 int i = cpu_logical_map[j];
 939                 struct task_struct *p;
 940                 
 941 #ifdef __SMP_PROF__
 942                 if (test_bit(i,&smp_idle_map)) 
 943                         smp_idle_count[i]++;
 944 #endif
 945                 p = current_set[i];
 946                 /*
 947                  * Do we have a real process?
 948                  */
 949                 if (p->pid) {
 950                         /* assume user-mode process */
 951                         unsigned long utime = ticks;
 952                         unsigned long stime = 0;
 953                         if (cpu == i) {
 954                                 utime = ticks-system;
 955                                 stime = system;
 956                         } else if (smp_proc_in_lock[i]) {
 957                                 utime = 0;
 958                                 stime = ticks;
 959                         }
 960                         update_one_process(p, ticks, utime, stime);
 961 
 962                         p->counter -= ticks;
 963                         if (p->counter >= 0)
 964                                 continue;
 965                         p->counter = 0;
 966                 } else {
 967                         /*
 968                          * Idle processor found, do we have anything
 969                          * we could run?
 970                          */
 971                         if (!(0x7fffffff & smp_process_available))
 972                                 continue;
 973                 }
 974                 /* Ok, we should reschedule, do the magic */
 975                 if (i==cpu)
 976                         need_resched = 1;
 977                 else
 978                         smp_message_pass(i, MSG_RESCHEDULE, 0L, 0);
 979         }
 980 #endif
 981 }
 982 
 983 static unsigned long lost_ticks = 0;
 984 static unsigned long lost_ticks_system = 0;
 985 
 986 static void timer_bh(void)
     /*  */
 987 {
 988         unsigned long ticks, system;
 989 
 990         run_old_timers();
 991 
 992         cli();
 993         run_timer_list();
 994         ticks = lost_ticks;
 995         lost_ticks = 0;
 996         system = lost_ticks_system;
 997         lost_ticks_system = 0;
 998         sti();
 999 
1000         if (ticks) {
1001                 calc_load(ticks);
1002                 update_wall_time(ticks);
1003                 update_process_times(ticks, system);
1004         }
1005 }
1006 
1007 /*
1008  * Run the bottom half stuff only about 100 times a second,
1009  * we'd just use up unnecessary CPU time for timer handling
1010  * otherwise
1011  */
1012 #if HZ > 100
1013 #define should_run_timers(x) ((x) >= HZ/100)
1014 #else
1015 #define should_run_timers(x) (1)
1016 #endif
1017 
1018 void do_timer(struct pt_regs * regs)
     /*  */
1019 {
1020         (*(unsigned long *)&jiffies)++;
1021         lost_ticks++;
1022         if (should_run_timers(lost_ticks))
1023                 mark_bh(TIMER_BH);
1024         if (!user_mode(regs)) {
1025                 lost_ticks_system++;
1026                 if (prof_buffer && current->pid) {
1027                         extern int _stext;
1028                         unsigned long ip = instruction_pointer(regs);
1029                         ip -= (unsigned long) &_stext;
1030                         ip >>= prof_shift;
1031                         if (ip < prof_len)
1032                                 prof_buffer[ip]++;
1033                 }
1034         }
1035         if (tq_timer)
1036                 mark_bh(TQUEUE_BH);
1037 }
1038 
1039 #ifndef __alpha__
1040 
1041 /*
1042  * For backwards compatibility?  This can be done in libc so Alpha
1043  * and all newer ports shouldn't need it.
1044  */
1045 asmlinkage unsigned int sys_alarm(unsigned int seconds)
     /*  */
1046 {
1047         struct itimerval it_new, it_old;
1048         unsigned int oldalarm;
1049 
1050         it_new.it_interval.tv_sec = it_new.it_interval.tv_usec = 0;
1051         it_new.it_value.tv_sec = seconds;
1052         it_new.it_value.tv_usec = 0;
1053         _setitimer(ITIMER_REAL, &it_new, &it_old);
1054         oldalarm = it_old.it_value.tv_sec;
1055         /* ehhh.. We can't return 0 if we have an alarm pending.. */
1056         /* And we'd better return too much than too little anyway */
1057         if (it_old.it_value.tv_usec)
1058                 oldalarm++;
1059         return oldalarm;
1060 }
1061 
1062 /*
1063  * The Alpha uses getxpid, getxuid, and getxgid instead.  Maybe this
1064  * should be moved into arch/i386 instead?
1065  */
1066 asmlinkage int sys_getpid(void)
     /*  */
1067 {
1068         return current->pid;
1069 }
1070 
1071 asmlinkage int sys_getppid(void)
     /*  */
1072 {
1073         return current->p_opptr->pid;
1074 }
1075 
1076 asmlinkage int sys_getuid(void)
     /*  */
1077 {
1078         return current->uid;
1079 }
1080 
1081 asmlinkage int sys_geteuid(void)
     /*  */
1082 {
1083         return current->euid;
1084 }
1085 
1086 asmlinkage int sys_getgid(void)
     /*  */
1087 {
1088         return current->gid;
1089 }
1090 
1091 asmlinkage int sys_getegid(void)
     /*  */
1092 {
1093         return current->egid;
1094 }
1095 
1096 /*
1097  * This has been replaced by sys_setpriority.  Maybe it should be
1098  * moved into the arch depedent tree for those ports that require
1099  * it for backward compatibility?
1100  */
1101 asmlinkage int sys_nice(int increment)
     /*  */
1102 {
1103         unsigned long newprio;
1104         int increase = 0;
1105 
1106         newprio = increment;
1107         if (increment < 0) {
1108                 if (!suser())
1109                         return -EPERM;
1110                 newprio = -increment;
1111                 increase = 1;
1112         }
1113         if (newprio > 40)
1114                 newprio = 40;
1115         /*
1116          * do a "normalization" of the priority (traditionally
1117          * unix nice values are -20..20, linux doesn't really
1118          * use that kind of thing, but uses the length of the
1119          * timeslice instead (default 150 msec). The rounding is
1120          * why we want to avoid negative values.
1121          */
1122         newprio = (newprio * DEF_PRIORITY + 10) / 20;
1123         increment = newprio;
1124         if (increase)
1125                 increment = -increment;
1126         newprio = current->priority - increment;
1127         if (newprio < 1)
1128                 newprio = 1;
1129         if (newprio > DEF_PRIORITY*2)
1130                 newprio = DEF_PRIORITY*2;
1131         current->priority = newprio;
1132         return 0;
1133 }
1134 
1135 #endif
1136 
1137 static struct task_struct *find_process_by_pid(pid_t pid) {
     /*  */
1138         struct task_struct *p, *q;
1139 
1140         if (pid == 0)
1141                 p = current;
1142         else {
1143                 p = 0;
1144                 for_each_task(q) {
1145                         if (q && q->pid == pid) {
1146                                 p = q;
1147                                 break;
1148                         }
1149                 }
1150         }
1151         return p;
1152 }
1153 
1154 static int setscheduler(pid_t pid, int policy, 
     /*  */
1155                         struct sched_param *param)
1156 {
1157         int error;
1158         struct sched_param lp;
1159         struct task_struct *p;
1160 
1161         if (!param || pid < 0)
1162                 return -EINVAL;
1163 
1164         error = verify_area(VERIFY_READ, param, sizeof(struct sched_param));
1165         if (error)
1166                 return error;
1167         memcpy_fromfs(&lp, param, sizeof(struct sched_param));
1168 
1169         p = find_process_by_pid(pid);
1170         if (!p)
1171                 return -ESRCH;
1172                         
1173         if (policy < 0)
1174                 policy = p->policy;
1175         else if (policy != SCHED_FIFO && policy != SCHED_RR &&
1176                  policy != SCHED_OTHER)
1177                 return -EINVAL;
1178         
1179         /*
1180          * Valid priorities for SCHED_FIFO and SCHED_RR are 1..99, valid
1181          * priority for SCHED_OTHER is 0.
1182          */
1183         if (lp.sched_priority < 0 || lp.sched_priority > 99)
1184                 return -EINVAL;
1185         if ((policy == SCHED_OTHER) != (lp.sched_priority == 0))
1186                 return -EINVAL;
1187 
1188         if ((policy == SCHED_FIFO || policy == SCHED_RR) && !suser())
1189                 return -EPERM;
1190         if ((current->euid != p->euid) && (current->euid != p->uid) &&
1191             !suser())
1192                 return -EPERM;
1193 
1194         p->policy = policy;
1195         p->rt_priority = lp.sched_priority;
1196         if (p->next_run)
1197                 move_last_runqueue(p);
1198         schedule();
1199 
1200         return 0;
1201 }
1202 
1203 asmlinkage int sys_sched_setscheduler(pid_t pid, int policy, 
     /*  */
1204                                       struct sched_param *param)
1205 {
1206         return setscheduler(pid, policy, param);
1207 }
1208 
1209 asmlinkage int sys_sched_setparam(pid_t pid, struct sched_param *param)
     /*  */
1210 {
1211         return setscheduler(pid, -1, param);
1212 }
1213 
1214 asmlinkage int sys_sched_getscheduler(pid_t pid)
     /*  */
1215 {
1216         struct task_struct *p;
1217 
1218         if (pid < 0)
1219                 return -EINVAL;
1220 
1221         p = find_process_by_pid(pid);
1222         if (!p)
1223                 return -ESRCH;
1224                         
1225         return p->policy;
1226 }
1227 
1228 asmlinkage int sys_sched_getparam(pid_t pid, struct sched_param *param)
     /*  */
1229 {
1230         int error;
1231         struct task_struct *p;
1232         struct sched_param lp;
1233 
1234         if (!param || pid < 0)
1235                 return -EINVAL;
1236 
1237         error = verify_area(VERIFY_WRITE, param, sizeof(struct sched_param));
1238         if (error)
1239                 return error;
1240 
1241         p = find_process_by_pid(pid);
1242         if (!p)
1243                 return -ESRCH;
1244 
1245         lp.sched_priority = p->rt_priority;
1246         memcpy_tofs(param, &lp, sizeof(struct sched_param));
1247 
1248         return 0;
1249 }
1250 
1251 asmlinkage int sys_sched_yield(void)
     /*  */
1252 {
1253         move_last_runqueue(current);
1254 
1255         return 0;
1256 }
1257 
1258 asmlinkage int sys_sched_get_priority_max(int policy)
     /*  */
1259 {
1260         switch (policy) {
1261               case SCHED_FIFO:
1262               case SCHED_RR:
1263                 return 99;
1264               case SCHED_OTHER:
1265                 return 0;
1266         }
1267 
1268         return -EINVAL;
1269 }
1270 
1271 asmlinkage int sys_sched_get_priority_min(int policy)
     /*  */
1272 {
1273         switch (policy) {
1274               case SCHED_FIFO:
1275               case SCHED_RR:
1276                 return 1;
1277               case SCHED_OTHER:
1278                 return 0;
1279         }
1280 
1281         return -EINVAL;
1282 }
1283 
1284 asmlinkage int sys_sched_rr_get_interval(pid_t pid, struct timespec *interval)
     /*  */
1285 {
1286         int error;
1287         struct timespec t;
1288 
1289         error = verify_area(VERIFY_WRITE, interval, sizeof(struct timespec));
1290         if (error)
1291                 return error;
1292         
1293         t.tv_sec = 0;
1294         t.tv_nsec = 0;   /* <-- Linus, please fill correct value in here */
1295         return -ENOSYS;  /* and then delete this line. Thanks!           */
1296         memcpy_tofs(interval, &t, sizeof(struct timespec));
1297 
1298         return 0;
1299 }
1300 
1301 /*
1302  * change timeval to jiffies, trying to avoid the 
1303  * most obvious overflows..
1304  */
1305 static unsigned long timespectojiffies(struct timespec *value)
     /*  */
1306 {
1307         unsigned long sec = (unsigned) value->tv_sec;
1308         long nsec = value->tv_nsec;
1309 
1310         if (sec > (LONG_MAX / HZ))
1311                 return LONG_MAX;
1312         nsec += 1000000000L / HZ - 1;
1313         nsec /= 1000000000L / HZ;
1314         return HZ * sec + nsec;
1315 }
1316 
1317 static void jiffiestotimespec(unsigned long jiffies, struct timespec *value)
     /*  */
1318 {
1319         value->tv_nsec = (jiffies % HZ) * (1000000000L / HZ);
1320         value->tv_sec = jiffies / HZ;
1321         return;
1322 }
1323 
1324 asmlinkage int sys_nanosleep(struct timespec *rqtp, struct timespec *rmtp)
     /*  */
1325 {
1326         int error;
1327         struct timespec t;
1328         unsigned long expire;
1329 
1330         error = verify_area(VERIFY_READ, rqtp, sizeof(struct timespec));
1331         if (error)
1332                 return error;
1333         memcpy_fromfs(&t, rqtp, sizeof(struct timespec));
1334         if (rmtp) {
1335                 error = verify_area(VERIFY_WRITE, rmtp,
1336                                     sizeof(struct timespec));
1337                 if (error)
1338                         return error;
1339         }
1340 
1341         if (t.tv_nsec >= 1000000000L || t.tv_nsec < 0 || t.tv_sec < 0)
1342                 return -EINVAL;
1343 
1344         if (t.tv_sec == 0 && t.tv_nsec <= 2000000L &&
1345             current->policy != SCHED_OTHER) {
1346                 /*
1347                  * Short delay requests up to 2 ms will be handled with
1348                  * high precision by a busy wait for all real-time processes.
1349                  */
1350                 udelay((t.tv_nsec + 999) / 1000);
1351                 return 0;
1352         }
1353 
1354         expire = timespectojiffies(&t) + (t.tv_sec || t.tv_nsec) + jiffies;
1355         current->timeout = expire;
1356         current->state = TASK_INTERRUPTIBLE;
1357         schedule();
1358 
1359         if (expire > jiffies) {
1360                 if (rmtp) {
1361                         jiffiestotimespec(expire - jiffies -
1362                                           (expire > jiffies + 1), &t);
1363                         memcpy_tofs(rmtp, &t, sizeof(struct timespec));
1364                 }
1365                 return -EINTR;
1366         }
1367 
1368         return 0;
1369 }
1370 
1371 static void show_task(int nr,struct task_struct * p)
     /*  */
1372 {
1373         unsigned long free;
1374         static const char * stat_nam[] = { "R", "S", "D", "Z", "T", "W" };
1375 
1376         printk("%-8s %3d ", p->comm, (p == current) ? -nr : nr);
1377         if (((unsigned) p->state) < sizeof(stat_nam)/sizeof(char *))
1378                 printk(stat_nam[p->state]);
1379         else
1380                 printk(" ");
1381 #if ((~0UL) == 0xffffffff)
1382         if (p == current)
1383                 printk(" current  ");
1384         else
1385                 printk(" %08lX ", thread_saved_pc(&p->tss));
1386 #else
1387         if (p == current)
1388                 printk("   current task   ");
1389         else
1390                 printk(" %016lx ", thread_saved_pc(&p->tss));
1391 #endif
1392         for (free = 1; free < PAGE_SIZE/sizeof(long) ; free++) {
1393                 if (((unsigned long *)p->kernel_stack_page)[free])
1394                         break;
1395         }
1396         printk("%5lu %5d %6d ", free*sizeof(long), p->pid, p->p_pptr->pid);
1397         if (p->p_cptr)
1398                 printk("%5d ", p->p_cptr->pid);
1399         else
1400                 printk("      ");
1401         if (p->p_ysptr)
1402                 printk("%7d", p->p_ysptr->pid);
1403         else
1404                 printk("       ");
1405         if (p->p_osptr)
1406                 printk(" %5d\n", p->p_osptr->pid);
1407         else
1408                 printk("\n");
1409 }
1410 
1411 void show_state(void)
     /*  */
1412 {
1413         int i;
1414 
1415 #if ((~0UL) == 0xffffffff)
1416         printk("\n"
1417                "                         free                        sibling\n");
1418         printk("  task             PC    stack   pid father child younger older\n");
1419 #else
1420         printk("\n"
1421                "                                 free                        sibling\n");
1422         printk("  task                 PC        stack   pid father child younger older\n");
1423 #endif
1424         for (i=0 ; i<NR_TASKS ; i++)
1425                 if (task[i])
1426                         show_task(i,task[i]);
1427 }
1428 
1429 void sched_init(void)
     /*  */
1430 {
1431         /*
1432          *      We have to do a little magic to get the first
1433          *      process right in SMP mode.
1434          */
1435         int cpu=smp_processor_id();
1436         current_set[cpu]=&init_task;
1437 #ifdef __SMP__  
1438         init_task.processor=cpu;
1439 #endif
1440         init_bh(TIMER_BH, timer_bh);
1441         init_bh(TQUEUE_BH, tqueue_bh);
1442         init_bh(IMMEDIATE_BH, immediate_bh);
1443 }
/* */
root/kernel/sched.c

DEFINITIONS
