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1 jermar 1
/*
2
 * Copyright (C) 2001-2004 Jakub Jermar
3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
13
 *   documentation and/or other materials provided with the distribution.
14
 * - The name of the author may not be used to endorse or promote products
15
 *   derived from this software without specific prior written permission.
16
 *
17
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
1248 jermar 29
/**
30
 * @file    scheduler.c
31
 * @brief   Scheduler and load balancing.
32
 *
1264 jermar 33
 * This file contains the scheduler and kcpulb kernel thread which
1248 jermar 34
 * performs load-balancing of per-CPU run queues.
35
 */
36
 
1 jermar 37
#include <proc/scheduler.h>
38
#include <proc/thread.h>
39
#include <proc/task.h>
378 jermar 40
#include <mm/frame.h>
41
#include <mm/page.h>
703 jermar 42
#include <mm/as.h>
1571 jermar 43
#include <time/delay.h>
378 jermar 44
#include <arch/asm.h>
45
#include <arch/faddr.h>
1104 jermar 46
#include <atomic.h>
378 jermar 47
#include <synch/spinlock.h>
1 jermar 48
#include <config.h>
49
#include <context.h>
50
#include <func.h>
51
#include <arch.h>
788 jermar 52
#include <adt/list.h>
68 decky 53
#include <panic.h>
1 jermar 54
#include <typedefs.h>
378 jermar 55
#include <cpu.h>
195 vana 56
#include <print.h>
227 jermar 57
#include <debug.h>
1 jermar 58
 
1187 jermar 59
static void before_task_runs(void);
60
static void before_thread_runs(void);
61
static void after_thread_ran(void);
898 jermar 62
static void scheduler_separated_stack(void);
195 vana 63
 
898 jermar 64
atomic_t nrdy;  /**< Number of ready threads in the system. */
65
 
1187 jermar 66
/** Carry out actions before new task runs. */
67
void before_task_runs(void)
68
{
69
    before_task_runs_arch();
70
}
71
 
897 jermar 72
/** Take actions before new thread runs.
107 decky 73
 *
118 jermar 74
 * Perform actions that need to be
75
 * taken before the newly selected
76
 * tread is passed control.
107 decky 77
 *
827 palkovsky 78
 * THREAD->lock is locked on entry
79
 *
107 decky 80
 */
52 vana 81
void before_thread_runs(void)
82
{
309 palkovsky 83
    before_thread_runs_arch();
906 palkovsky 84
#ifdef CONFIG_FPU_LAZY
309 palkovsky 85
    if(THREAD==CPU->fpu_owner)
86
        fpu_enable();
87
    else
88
        fpu_disable();
906 palkovsky 89
#else
309 palkovsky 90
    fpu_enable();
91
    if (THREAD->fpu_context_exists)
906 palkovsky 92
        fpu_context_restore(THREAD->saved_fpu_context);
309 palkovsky 93
    else {
906 palkovsky 94
        fpu_init();
309 palkovsky 95
        THREAD->fpu_context_exists=1;
96
    }
906 palkovsky 97
#endif
52 vana 98
}
99
 
898 jermar 100
/** Take actions after THREAD had run.
897 jermar 101
 *
102
 * Perform actions that need to be
103
 * taken after the running thread
898 jermar 104
 * had been preempted by the scheduler.
897 jermar 105
 *
106
 * THREAD->lock is locked on entry
107
 *
108
 */
109
void after_thread_ran(void)
110
{
111
    after_thread_ran_arch();
112
}
113
 
458 decky 114
#ifdef CONFIG_FPU_LAZY
309 palkovsky 115
void scheduler_fpu_lazy_request(void)
116
{
907 palkovsky 117
restart:
309 palkovsky 118
    fpu_enable();
827 palkovsky 119
    spinlock_lock(&CPU->lock);
120
 
121
    /* Save old context */
309 palkovsky 122
    if (CPU->fpu_owner != NULL) {  
827 palkovsky 123
        spinlock_lock(&CPU->fpu_owner->lock);
906 palkovsky 124
        fpu_context_save(CPU->fpu_owner->saved_fpu_context);
309 palkovsky 125
        /* don't prevent migration */
126
        CPU->fpu_owner->fpu_context_engaged=0;
827 palkovsky 127
        spinlock_unlock(&CPU->fpu_owner->lock);
907 palkovsky 128
        CPU->fpu_owner = NULL;
309 palkovsky 129
    }
827 palkovsky 130
 
131
    spinlock_lock(&THREAD->lock);
898 jermar 132
    if (THREAD->fpu_context_exists) {
906 palkovsky 133
        fpu_context_restore(THREAD->saved_fpu_context);
898 jermar 134
    } else {
906 palkovsky 135
        /* Allocate FPU context */
136
        if (!THREAD->saved_fpu_context) {
137
            /* Might sleep */
138
            spinlock_unlock(&THREAD->lock);
907 palkovsky 139
            spinlock_unlock(&CPU->lock);
906 palkovsky 140
            THREAD->saved_fpu_context = slab_alloc(fpu_context_slab,
141
                                   0);
907 palkovsky 142
            /* We may have switched CPUs during slab_alloc */
143
            goto restart;
906 palkovsky 144
        }
145
        fpu_init();
309 palkovsky 146
        THREAD->fpu_context_exists=1;
147
    }
148
    CPU->fpu_owner=THREAD;
149
    THREAD->fpu_context_engaged = 1;
898 jermar 150
    spinlock_unlock(&THREAD->lock);
827 palkovsky 151
 
152
    spinlock_unlock(&CPU->lock);
309 palkovsky 153
}
154
#endif
52 vana 155
 
107 decky 156
/** Initialize scheduler
157
 *
158
 * Initialize kernel scheduler.
159
 *
160
 */
1 jermar 161
void scheduler_init(void)
162
{
163
}
164
 
107 decky 165
/** Get thread to be scheduled
166
 *
167
 * Get the optimal thread to be scheduled
109 jermar 168
 * according to thread accounting and scheduler
107 decky 169
 * policy.
170
 *
171
 * @return Thread to be scheduled.
172
 *
173
 */
483 jermar 174
static thread_t *find_best_thread(void)
1 jermar 175
{
176
    thread_t *t;
177
    runq_t *r;
783 palkovsky 178
    int i;
1 jermar 179
 
227 jermar 180
    ASSERT(CPU != NULL);
181
 
1 jermar 182
loop:
413 jermar 183
    interrupts_enable();
1 jermar 184
 
783 palkovsky 185
    if (atomic_get(&CPU->nrdy) == 0) {
1 jermar 186
        /*
187
         * For there was nothing to run, the CPU goes to sleep
188
         * until a hardware interrupt or an IPI comes.
189
         * This improves energy saving and hyperthreading.
190
         */
785 jermar 191
 
192
        /*
193
         * An interrupt might occur right now and wake up a thread.
194
         * In such case, the CPU will continue to go to sleep
195
         * even though there is a runnable thread.
196
         */
197
 
1 jermar 198
         cpu_sleep();
199
         goto loop;
200
    }
201
 
413 jermar 202
    interrupts_disable();
114 jermar 203
 
898 jermar 204
    for (i = 0; i<RQ_COUNT; i++) {
15 jermar 205
        r = &CPU->rq[i];
1 jermar 206
        spinlock_lock(&r->lock);
207
        if (r->n == 0) {
208
            /*
209
             * If this queue is empty, try a lower-priority queue.
210
             */
211
            spinlock_unlock(&r->lock);
212
            continue;
213
        }
213 jermar 214
 
783 palkovsky 215
        atomic_dec(&CPU->nrdy);
475 jermar 216
        atomic_dec(&nrdy);
1 jermar 217
        r->n--;
218
 
219
        /*
220
         * Take the first thread from the queue.
221
         */
222
        t = list_get_instance(r->rq_head.next, thread_t, rq_link);
223
        list_remove(&t->rq_link);
224
 
225
        spinlock_unlock(&r->lock);
226
 
227
        spinlock_lock(&t->lock);
15 jermar 228
        t->cpu = CPU;
1 jermar 229
 
230
        t->ticks = us2ticks((i+1)*10000);
898 jermar 231
        t->priority = i;    /* correct rq index */
1 jermar 232
 
233
        /*
234
         * Clear the X_STOLEN flag so that t can be migrated when load balancing needs emerge.
235
         */
236
        t->flags &= ~X_STOLEN;
237
        spinlock_unlock(&t->lock);
238
 
239
        return t;
240
    }
241
    goto loop;
242
 
243
}
244
 
107 decky 245
/** Prevent rq starvation
246
 *
247
 * Prevent low priority threads from starving in rq's.
248
 *
249
 * When the function decides to relink rq's, it reconnects
250
 * respective pointers so that in result threads with 'pri'
1229 jermar 251
 * greater or equal @start are moved to a higher-priority queue.
107 decky 252
 *
253
 * @param start Threshold priority.
254
 *
1 jermar 255
 */
452 decky 256
static void relink_rq(int start)
1 jermar 257
{
258
    link_t head;
259
    runq_t *r;
260
    int i, n;
261
 
262
    list_initialize(&head);
15 jermar 263
    spinlock_lock(&CPU->lock);
264
    if (CPU->needs_relink > NEEDS_RELINK_MAX) {
1 jermar 265
        for (i = start; i<RQ_COUNT-1; i++) {
266
            /* remember and empty rq[i + 1] */
15 jermar 267
            r = &CPU->rq[i + 1];
1 jermar 268
            spinlock_lock(&r->lock);
269
            list_concat(&head, &r->rq_head);
270
            n = r->n;
271
            r->n = 0;
272
            spinlock_unlock(&r->lock);
273
 
274
            /* append rq[i + 1] to rq[i] */
15 jermar 275
            r = &CPU->rq[i];
1 jermar 276
            spinlock_lock(&r->lock);
277
            list_concat(&r->rq_head, &head);
278
            r->n += n;
279
            spinlock_unlock(&r->lock);
280
        }
15 jermar 281
        CPU->needs_relink = 0;
1 jermar 282
    }
784 palkovsky 283
    spinlock_unlock(&CPU->lock);
1 jermar 284
 
285
}
286
 
898 jermar 287
/** The scheduler
288
 *
289
 * The thread scheduling procedure.
290
 * Passes control directly to
291
 * scheduler_separated_stack().
292
 *
293
 */
294
void scheduler(void)
295
{
296
    volatile ipl_t ipl;
107 decky 297
 
898 jermar 298
    ASSERT(CPU != NULL);
299
 
300
    ipl = interrupts_disable();
301
 
302
    if (atomic_get(&haltstate))
303
        halt();
1007 decky 304
 
898 jermar 305
    if (THREAD) {
306
        spinlock_lock(&THREAD->lock);
906 palkovsky 307
#ifndef CONFIG_FPU_LAZY
308
        fpu_context_save(THREAD->saved_fpu_context);
309
#endif
898 jermar 310
        if (!context_save(&THREAD->saved_context)) {
311
            /*
312
             * This is the place where threads leave scheduler();
313
             */
314
            spinlock_unlock(&THREAD->lock);
315
            interrupts_restore(THREAD->saved_context.ipl);
1007 decky 316
 
898 jermar 317
            return;
318
        }
319
 
320
        /*
321
         * Interrupt priority level of preempted thread is recorded here
322
         * to facilitate scheduler() invocations from interrupts_disable()'d
323
         * code (e.g. waitq_sleep_timeout()).
324
         */
325
        THREAD->saved_context.ipl = ipl;
326
    }
327
 
328
    /*
329
     * Through the 'THE' structure, we keep track of THREAD, TASK, CPU, VM
330
     * and preemption counter. At this point THE could be coming either
331
     * from THREAD's or CPU's stack.
332
     */
333
    the_copy(THE, (the_t *) CPU->stack);
334
 
335
    /*
336
     * We may not keep the old stack.
337
     * Reason: If we kept the old stack and got blocked, for instance, in
338
     * find_best_thread(), the old thread could get rescheduled by another
339
     * CPU and overwrite the part of its own stack that was also used by
340
     * the scheduler on this CPU.
341
     *
342
     * Moreover, we have to bypass the compiler-generated POP sequence
343
     * which is fooled by SP being set to the very top of the stack.
344
     * Therefore the scheduler() function continues in
345
     * scheduler_separated_stack().
346
     */
347
    context_save(&CPU->saved_context);
348
    context_set(&CPU->saved_context, FADDR(scheduler_separated_stack), (__address) CPU->stack, CPU_STACK_SIZE);
349
    context_restore(&CPU->saved_context);
350
    /* not reached */
351
}
352
 
107 decky 353
/** Scheduler stack switch wrapper
354
 *
355
 * Second part of the scheduler() function
356
 * using new stack. Handling the actual context
357
 * switch to a new thread.
358
 *
787 palkovsky 359
 * Assume THREAD->lock is held.
107 decky 360
 */
898 jermar 361
void scheduler_separated_stack(void)
1 jermar 362
{
363
    int priority;
1007 decky 364
 
227 jermar 365
    ASSERT(CPU != NULL);
1007 decky 366
 
15 jermar 367
    if (THREAD) {
898 jermar 368
        /* must be run after the switch to scheduler stack */
897 jermar 369
        after_thread_ran();
370
 
15 jermar 371
        switch (THREAD->state) {
1 jermar 372
            case Running:
125 jermar 373
            spinlock_unlock(&THREAD->lock);
374
            thread_ready(THREAD);
375
            break;
1 jermar 376
 
377
            case Exiting:
1571 jermar 378
repeat:
379
                if (THREAD->detached) {
380
                thread_destroy(THREAD);
381
            } else {
382
                /*
383
                 * The thread structure is kept allocated until somebody
384
                 * calls thread_detach() on it.
385
                 */
386
                if (!spinlock_trylock(&THREAD->join_wq.lock)) {
387
                    /*
388
                     * Avoid deadlock.
389
                     */
390
                    spinlock_unlock(&THREAD->lock);
391
                    delay(10);
392
                    spinlock_lock(&THREAD->lock);
393
                    goto repeat;
394
                }
395
                _waitq_wakeup_unsafe(&THREAD->join_wq, false);
396
                spinlock_unlock(&THREAD->join_wq.lock);
397
 
398
                THREAD->state = Undead;
399
                spinlock_unlock(&THREAD->lock);
400
            }
125 jermar 401
            break;
787 palkovsky 402
 
1 jermar 403
            case Sleeping:
125 jermar 404
            /*
405
             * Prefer the thread after it's woken up.
406
             */
413 jermar 407
            THREAD->priority = -1;
1 jermar 408
 
125 jermar 409
            /*
410
             * We need to release wq->lock which we locked in waitq_sleep().
411
             * Address of wq->lock is kept in THREAD->sleep_queue.
412
             */
413
            spinlock_unlock(&THREAD->sleep_queue->lock);
1 jermar 414
 
125 jermar 415
            /*
416
             * Check for possible requests for out-of-context invocation.
417
             */
418
            if (THREAD->call_me) {
419
                THREAD->call_me(THREAD->call_me_with);
420
                THREAD->call_me = NULL;
421
                THREAD->call_me_with = NULL;
422
            }
1 jermar 423
 
125 jermar 424
            spinlock_unlock(&THREAD->lock);
1 jermar 425
 
125 jermar 426
            break;
427
 
1 jermar 428
            default:
125 jermar 429
            /*
430
             * Entering state is unexpected.
431
             */
432
            panic("tid%d: unexpected state %s\n", THREAD->tid, thread_states[THREAD->state]);
433
            break;
1 jermar 434
        }
897 jermar 435
 
15 jermar 436
        THREAD = NULL;
1 jermar 437
    }
198 jermar 438
 
15 jermar 439
    THREAD = find_best_thread();
1 jermar 440
 
15 jermar 441
    spinlock_lock(&THREAD->lock);
413 jermar 442
    priority = THREAD->priority;
15 jermar 443
    spinlock_unlock(&THREAD->lock);
192 jermar 444
 
1 jermar 445
    relink_rq(priority);       
446
 
447
    /*
448
     * If both the old and the new task are the same, lots of work is avoided.
449
     */
15 jermar 450
    if (TASK != THREAD->task) {
703 jermar 451
        as_t *as1 = NULL;
452
        as_t *as2;
1 jermar 453
 
15 jermar 454
        if (TASK) {
455
            spinlock_lock(&TASK->lock);
703 jermar 456
            as1 = TASK->as;
15 jermar 457
            spinlock_unlock(&TASK->lock);
1 jermar 458
        }
459
 
15 jermar 460
        spinlock_lock(&THREAD->task->lock);
703 jermar 461
        as2 = THREAD->task->as;
15 jermar 462
        spinlock_unlock(&THREAD->task->lock);
1 jermar 463
 
464
        /*
703 jermar 465
         * Note that it is possible for two tasks to share one address space.
1 jermar 466
         */
703 jermar 467
        if (as1 != as2) {
1 jermar 468
            /*
703 jermar 469
             * Both tasks and address spaces are different.
1 jermar 470
             * Replace the old one with the new one.
471
             */
823 jermar 472
            as_switch(as1, as2);
1 jermar 473
        }
906 palkovsky 474
        TASK = THREAD->task;
1187 jermar 475
        before_task_runs();
1 jermar 476
    }
477
 
1380 jermar 478
    spinlock_lock(&THREAD->lock);  
15 jermar 479
    THREAD->state = Running;
1 jermar 480
 
906 palkovsky 481
#ifdef SCHEDULER_VERBOSE
1196 cejka 482
    printf("cpu%d: tid %d (priority=%d,ticks=%lld,nrdy=%ld)\n", CPU->id, THREAD->tid, THREAD->priority, THREAD->ticks, atomic_get(&CPU->nrdy));
906 palkovsky 483
#endif  
1 jermar 484
 
213 jermar 485
    /*
897 jermar 486
     * Some architectures provide late kernel PA2KA(identity)
487
     * mapping in a page fault handler. However, the page fault
488
     * handler uses the kernel stack of the running thread and
489
     * therefore cannot be used to map it. The kernel stack, if
490
     * necessary, is to be mapped in before_thread_runs(). This
491
     * function must be executed before the switch to the new stack.
492
     */
493
    before_thread_runs();
494
 
495
    /*
213 jermar 496
     * Copy the knowledge of CPU, TASK, THREAD and preemption counter to thread's stack.
497
     */
184 jermar 498
    the_copy(THE, (the_t *) THREAD->kstack);
499
 
15 jermar 500
    context_restore(&THREAD->saved_context);
1 jermar 501
    /* not reached */
502
}
503
 
458 decky 504
#ifdef CONFIG_SMP
107 decky 505
/** Load balancing thread
506
 *
507
 * SMP load balancing thread, supervising thread supplies
508
 * for the CPU it's wired to.
509
 *
510
 * @param arg Generic thread argument (unused).
511
 *
1 jermar 512
 */
513
void kcpulb(void *arg)
514
{
515
    thread_t *t;
783 palkovsky 516
    int count, average, i, j, k = 0;
413 jermar 517
    ipl_t ipl;
1 jermar 518
 
519
loop:
520
    /*
779 jermar 521
     * Work in 1s intervals.
1 jermar 522
     */
779 jermar 523
    thread_sleep(1);
1 jermar 524
 
525
not_satisfied:
526
    /*
527
     * Calculate the number of threads that will be migrated/stolen from
528
     * other CPU's. Note that situation can have changed between two
529
     * passes. Each time get the most up to date counts.
530
     */
784 palkovsky 531
    average = atomic_get(&nrdy) / config.cpu_active + 1;
783 palkovsky 532
    count = average - atomic_get(&CPU->nrdy);
1 jermar 533
 
784 palkovsky 534
    if (count <= 0)
1 jermar 535
        goto satisfied;
536
 
537
    /*
538
     * Searching least priority queues on all CPU's first and most priority queues on all CPU's last.
539
     */
540
    for (j=RQ_COUNT-1; j >= 0; j--) {
541
        for (i=0; i < config.cpu_active; i++) {
542
            link_t *l;
543
            runq_t *r;
544
            cpu_t *cpu;
545
 
546
            cpu = &cpus[(i + k) % config.cpu_active];
547
 
548
            /*
549
             * Not interested in ourselves.
550
             * Doesn't require interrupt disabling for kcpulb is X_WIRED.
551
             */
15 jermar 552
            if (CPU == cpu)
783 palkovsky 553
                continue;
554
            if (atomic_get(&cpu->nrdy) <= average)
555
                continue;
1 jermar 556
 
784 palkovsky 557
            ipl = interrupts_disable();
115 jermar 558
            r = &cpu->rq[j];
1 jermar 559
            spinlock_lock(&r->lock);
560
            if (r->n == 0) {
561
                spinlock_unlock(&r->lock);
413 jermar 562
                interrupts_restore(ipl);
1 jermar 563
                continue;
564
            }
565
 
566
            t = NULL;
567
            l = r->rq_head.prev;    /* search rq from the back */
568
            while (l != &r->rq_head) {
569
                t = list_get_instance(l, thread_t, rq_link);
570
                /*
125 jermar 571
                 * We don't want to steal CPU-wired threads neither threads already stolen.
1 jermar 572
                 * The latter prevents threads from migrating between CPU's without ever being run.
125 jermar 573
                 * We don't want to steal threads whose FPU context is still in CPU.
73 vana 574
                 */
1 jermar 575
                spinlock_lock(&t->lock);
73 vana 576
                if ( (!(t->flags & (X_WIRED | X_STOLEN))) && (!(t->fpu_context_engaged)) ) {
1 jermar 577
                    /*
578
                     * Remove t from r.
579
                     */
580
                    spinlock_unlock(&t->lock);
581
 
783 palkovsky 582
                    atomic_dec(&cpu->nrdy);
475 jermar 583
                    atomic_dec(&nrdy);
1 jermar 584
 
125 jermar 585
                    r->n--;
1 jermar 586
                    list_remove(&t->rq_link);
587
 
588
                    break;
589
                }
590
                spinlock_unlock(&t->lock);
591
                l = l->prev;
592
                t = NULL;
593
            }
594
            spinlock_unlock(&r->lock);
595
 
596
            if (t) {
597
                /*
598
                 * Ready t on local CPU
599
                 */
600
                spinlock_lock(&t->lock);
906 palkovsky 601
#ifdef KCPULB_VERBOSE
1196 cejka 602
                printf("kcpulb%d: TID %d -> cpu%d, nrdy=%ld, avg=%nd\n", CPU->id, t->tid, CPU->id, atomic_get(&CPU->nrdy), atomic_get(&nrdy) / config.cpu_active);
906 palkovsky 603
#endif
1 jermar 604
                t->flags |= X_STOLEN;
1115 jermar 605
                t->state = Entering;
1 jermar 606
                spinlock_unlock(&t->lock);
607
 
608
                thread_ready(t);
609
 
413 jermar 610
                interrupts_restore(ipl);
1 jermar 611
 
612
                if (--count == 0)
613
                    goto satisfied;
614
 
615
                /*
125 jermar 616
                 * We are not satisfied yet, focus on another CPU next time.
1 jermar 617
                 */
618
                k++;
619
 
620
                continue;
621
            }
413 jermar 622
            interrupts_restore(ipl);
1 jermar 623
        }
624
    }
625
 
783 palkovsky 626
    if (atomic_get(&CPU->nrdy)) {
1 jermar 627
        /*
628
         * Be a little bit light-weight and let migrated threads run.
629
         */
630
        scheduler();
779 jermar 631
    } else {
1 jermar 632
        /*
633
         * We failed to migrate a single thread.
779 jermar 634
         * Give up this turn.
1 jermar 635
         */
779 jermar 636
        goto loop;
1 jermar 637
    }
638
 
639
    goto not_satisfied;
125 jermar 640
 
1 jermar 641
satisfied:
642
    goto loop;
643
}
644
 
458 decky 645
#endif /* CONFIG_SMP */
775 palkovsky 646
 
647
 
648
/** Print information about threads & scheduler queues */
649
void sched_print_list(void)
650
{
651
    ipl_t ipl;
652
    int cpu,i;
653
    runq_t *r;
654
    thread_t *t;
655
    link_t *cur;
656
 
657
    /* We are going to mess with scheduler structures,
658
     * let's not be interrupted */
659
    ipl = interrupts_disable();
660
    for (cpu=0;cpu < config.cpu_count; cpu++) {
898 jermar 661
 
775 palkovsky 662
        if (!cpus[cpu].active)
663
            continue;
898 jermar 664
 
775 palkovsky 665
        spinlock_lock(&cpus[cpu].lock);
1221 decky 666
        printf("cpu%d: address=%p, nrdy=%ld, needs_relink=%ld\n",
1062 jermar 667
               cpus[cpu].id, &cpus[cpu], atomic_get(&cpus[cpu].nrdy), cpus[cpu].needs_relink);
775 palkovsky 668
 
669
        for (i=0; i<RQ_COUNT; i++) {
670
            r = &cpus[cpu].rq[i];
671
            spinlock_lock(&r->lock);
672
            if (!r->n) {
673
                spinlock_unlock(&r->lock);
674
                continue;
675
            }
898 jermar 676
            printf("\trq[%d]: ", i);
775 palkovsky 677
            for (cur=r->rq_head.next; cur!=&r->rq_head; cur=cur->next) {
678
                t = list_get_instance(cur, thread_t, rq_link);
679
                printf("%d(%s) ", t->tid,
680
                       thread_states[t->state]);
681
            }
682
            printf("\n");
683
            spinlock_unlock(&r->lock);
684
        }
685
        spinlock_unlock(&cpus[cpu].lock);
686
    }
687
 
688
    interrupts_restore(ipl);
689
}