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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
 
1702 cejka 29
 
1705 cejka 30
 /** @addtogroup genericproc
1702 cejka 31
 * @{
32
 */
33
 
1248 jermar 34
/**
1702 cejka 35
 * @file
1248 jermar 36
 * @brief   Scheduler and load balancing.
37
 *
1264 jermar 38
 * This file contains the scheduler and kcpulb kernel thread which
1248 jermar 39
 * performs load-balancing of per-CPU run queues.
40
 */
41
 
1 jermar 42
#include <proc/scheduler.h>
43
#include <proc/thread.h>
44
#include <proc/task.h>
378 jermar 45
#include <mm/frame.h>
46
#include <mm/page.h>
703 jermar 47
#include <mm/as.h>
1571 jermar 48
#include <time/delay.h>
378 jermar 49
#include <arch/asm.h>
50
#include <arch/faddr.h>
1104 jermar 51
#include <atomic.h>
378 jermar 52
#include <synch/spinlock.h>
1 jermar 53
#include <config.h>
54
#include <context.h>
55
#include <func.h>
56
#include <arch.h>
788 jermar 57
#include <adt/list.h>
68 decky 58
#include <panic.h>
1 jermar 59
#include <typedefs.h>
378 jermar 60
#include <cpu.h>
195 vana 61
#include <print.h>
227 jermar 62
#include <debug.h>
1 jermar 63
 
1187 jermar 64
static void before_task_runs(void);
65
static void before_thread_runs(void);
66
static void after_thread_ran(void);
898 jermar 67
static void scheduler_separated_stack(void);
195 vana 68
 
898 jermar 69
atomic_t nrdy;  /**< Number of ready threads in the system. */
70
 
1187 jermar 71
/** Carry out actions before new task runs. */
72
void before_task_runs(void)
73
{
74
    before_task_runs_arch();
75
}
76
 
897 jermar 77
/** Take actions before new thread runs.
107 decky 78
 *
118 jermar 79
 * Perform actions that need to be
80
 * taken before the newly selected
81
 * tread is passed control.
107 decky 82
 *
827 palkovsky 83
 * THREAD->lock is locked on entry
84
 *
107 decky 85
 */
52 vana 86
void before_thread_runs(void)
87
{
309 palkovsky 88
    before_thread_runs_arch();
906 palkovsky 89
#ifdef CONFIG_FPU_LAZY
309 palkovsky 90
    if(THREAD==CPU->fpu_owner)
91
        fpu_enable();
92
    else
93
        fpu_disable();
906 palkovsky 94
#else
309 palkovsky 95
    fpu_enable();
96
    if (THREAD->fpu_context_exists)
906 palkovsky 97
        fpu_context_restore(THREAD->saved_fpu_context);
309 palkovsky 98
    else {
906 palkovsky 99
        fpu_init();
309 palkovsky 100
        THREAD->fpu_context_exists=1;
101
    }
906 palkovsky 102
#endif
52 vana 103
}
104
 
898 jermar 105
/** Take actions after THREAD had run.
897 jermar 106
 *
107
 * Perform actions that need to be
108
 * taken after the running thread
898 jermar 109
 * had been preempted by the scheduler.
897 jermar 110
 *
111
 * THREAD->lock is locked on entry
112
 *
113
 */
114
void after_thread_ran(void)
115
{
116
    after_thread_ran_arch();
117
}
118
 
458 decky 119
#ifdef CONFIG_FPU_LAZY
309 palkovsky 120
void scheduler_fpu_lazy_request(void)
121
{
907 palkovsky 122
restart:
309 palkovsky 123
    fpu_enable();
827 palkovsky 124
    spinlock_lock(&CPU->lock);
125
 
126
    /* Save old context */
309 palkovsky 127
    if (CPU->fpu_owner != NULL) {  
827 palkovsky 128
        spinlock_lock(&CPU->fpu_owner->lock);
906 palkovsky 129
        fpu_context_save(CPU->fpu_owner->saved_fpu_context);
309 palkovsky 130
        /* don't prevent migration */
131
        CPU->fpu_owner->fpu_context_engaged=0;
827 palkovsky 132
        spinlock_unlock(&CPU->fpu_owner->lock);
907 palkovsky 133
        CPU->fpu_owner = NULL;
309 palkovsky 134
    }
827 palkovsky 135
 
136
    spinlock_lock(&THREAD->lock);
898 jermar 137
    if (THREAD->fpu_context_exists) {
906 palkovsky 138
        fpu_context_restore(THREAD->saved_fpu_context);
898 jermar 139
    } else {
906 palkovsky 140
        /* Allocate FPU context */
141
        if (!THREAD->saved_fpu_context) {
142
            /* Might sleep */
143
            spinlock_unlock(&THREAD->lock);
907 palkovsky 144
            spinlock_unlock(&CPU->lock);
906 palkovsky 145
            THREAD->saved_fpu_context = slab_alloc(fpu_context_slab,
146
                                   0);
907 palkovsky 147
            /* We may have switched CPUs during slab_alloc */
148
            goto restart;
906 palkovsky 149
        }
150
        fpu_init();
309 palkovsky 151
        THREAD->fpu_context_exists=1;
152
    }
153
    CPU->fpu_owner=THREAD;
154
    THREAD->fpu_context_engaged = 1;
898 jermar 155
    spinlock_unlock(&THREAD->lock);
827 palkovsky 156
 
157
    spinlock_unlock(&CPU->lock);
309 palkovsky 158
}
159
#endif
52 vana 160
 
107 decky 161
/** Initialize scheduler
162
 *
163
 * Initialize kernel scheduler.
164
 *
165
 */
1 jermar 166
void scheduler_init(void)
167
{
168
}
169
 
107 decky 170
/** Get thread to be scheduled
171
 *
172
 * Get the optimal thread to be scheduled
109 jermar 173
 * according to thread accounting and scheduler
107 decky 174
 * policy.
175
 *
176
 * @return Thread to be scheduled.
177
 *
178
 */
483 jermar 179
static thread_t *find_best_thread(void)
1 jermar 180
{
181
    thread_t *t;
182
    runq_t *r;
783 palkovsky 183
    int i;
1 jermar 184
 
227 jermar 185
    ASSERT(CPU != NULL);
186
 
1 jermar 187
loop:
413 jermar 188
    interrupts_enable();
1 jermar 189
 
783 palkovsky 190
    if (atomic_get(&CPU->nrdy) == 0) {
1 jermar 191
        /*
192
         * For there was nothing to run, the CPU goes to sleep
193
         * until a hardware interrupt or an IPI comes.
194
         * This improves energy saving and hyperthreading.
195
         */
785 jermar 196
 
197
        /*
198
         * An interrupt might occur right now and wake up a thread.
199
         * In such case, the CPU will continue to go to sleep
200
         * even though there is a runnable thread.
201
         */
202
 
1 jermar 203
         cpu_sleep();
204
         goto loop;
205
    }
206
 
413 jermar 207
    interrupts_disable();
114 jermar 208
 
898 jermar 209
    for (i = 0; i<RQ_COUNT; i++) {
15 jermar 210
        r = &CPU->rq[i];
1 jermar 211
        spinlock_lock(&r->lock);
212
        if (r->n == 0) {
213
            /*
214
             * If this queue is empty, try a lower-priority queue.
215
             */
216
            spinlock_unlock(&r->lock);
217
            continue;
218
        }
213 jermar 219
 
783 palkovsky 220
        atomic_dec(&CPU->nrdy);
475 jermar 221
        atomic_dec(&nrdy);
1 jermar 222
        r->n--;
223
 
224
        /*
225
         * Take the first thread from the queue.
226
         */
227
        t = list_get_instance(r->rq_head.next, thread_t, rq_link);
228
        list_remove(&t->rq_link);
229
 
230
        spinlock_unlock(&r->lock);
231
 
232
        spinlock_lock(&t->lock);
15 jermar 233
        t->cpu = CPU;
1 jermar 234
 
235
        t->ticks = us2ticks((i+1)*10000);
898 jermar 236
        t->priority = i;    /* correct rq index */
1 jermar 237
 
238
        /*
239
         * Clear the X_STOLEN flag so that t can be migrated when load balancing needs emerge.
240
         */
241
        t->flags &= ~X_STOLEN;
242
        spinlock_unlock(&t->lock);
243
 
244
        return t;
245
    }
246
    goto loop;
247
 
248
}
249
 
107 decky 250
/** Prevent rq starvation
251
 *
252
 * Prevent low priority threads from starving in rq's.
253
 *
254
 * When the function decides to relink rq's, it reconnects
255
 * respective pointers so that in result threads with 'pri'
1229 jermar 256
 * greater or equal @start are moved to a higher-priority queue.
107 decky 257
 *
258
 * @param start Threshold priority.
259
 *
1 jermar 260
 */
452 decky 261
static void relink_rq(int start)
1 jermar 262
{
263
    link_t head;
264
    runq_t *r;
265
    int i, n;
266
 
267
    list_initialize(&head);
15 jermar 268
    spinlock_lock(&CPU->lock);
269
    if (CPU->needs_relink > NEEDS_RELINK_MAX) {
1 jermar 270
        for (i = start; i<RQ_COUNT-1; i++) {
271
            /* remember and empty rq[i + 1] */
15 jermar 272
            r = &CPU->rq[i + 1];
1 jermar 273
            spinlock_lock(&r->lock);
274
            list_concat(&head, &r->rq_head);
275
            n = r->n;
276
            r->n = 0;
277
            spinlock_unlock(&r->lock);
278
 
279
            /* append rq[i + 1] to rq[i] */
15 jermar 280
            r = &CPU->rq[i];
1 jermar 281
            spinlock_lock(&r->lock);
282
            list_concat(&r->rq_head, &head);
283
            r->n += n;
284
            spinlock_unlock(&r->lock);
285
        }
15 jermar 286
        CPU->needs_relink = 0;
1 jermar 287
    }
784 palkovsky 288
    spinlock_unlock(&CPU->lock);
1 jermar 289
 
290
}
291
 
898 jermar 292
/** The scheduler
293
 *
294
 * The thread scheduling procedure.
295
 * Passes control directly to
296
 * scheduler_separated_stack().
297
 *
298
 */
299
void scheduler(void)
300
{
301
    volatile ipl_t ipl;
107 decky 302
 
898 jermar 303
    ASSERT(CPU != NULL);
304
 
305
    ipl = interrupts_disable();
306
 
307
    if (atomic_get(&haltstate))
308
        halt();
1007 decky 309
 
898 jermar 310
    if (THREAD) {
311
        spinlock_lock(&THREAD->lock);
906 palkovsky 312
#ifndef CONFIG_FPU_LAZY
313
        fpu_context_save(THREAD->saved_fpu_context);
314
#endif
898 jermar 315
        if (!context_save(&THREAD->saved_context)) {
316
            /*
317
             * This is the place where threads leave scheduler();
318
             */
319
            spinlock_unlock(&THREAD->lock);
320
            interrupts_restore(THREAD->saved_context.ipl);
1007 decky 321
 
898 jermar 322
            return;
323
        }
324
 
325
        /*
326
         * Interrupt priority level of preempted thread is recorded here
327
         * to facilitate scheduler() invocations from interrupts_disable()'d
328
         * code (e.g. waitq_sleep_timeout()).
329
         */
330
        THREAD->saved_context.ipl = ipl;
331
    }
332
 
333
    /*
334
     * Through the 'THE' structure, we keep track of THREAD, TASK, CPU, VM
335
     * and preemption counter. At this point THE could be coming either
336
     * from THREAD's or CPU's stack.
337
     */
338
    the_copy(THE, (the_t *) CPU->stack);
339
 
340
    /*
341
     * We may not keep the old stack.
342
     * Reason: If we kept the old stack and got blocked, for instance, in
343
     * find_best_thread(), the old thread could get rescheduled by another
344
     * CPU and overwrite the part of its own stack that was also used by
345
     * the scheduler on this CPU.
346
     *
347
     * Moreover, we have to bypass the compiler-generated POP sequence
348
     * which is fooled by SP being set to the very top of the stack.
349
     * Therefore the scheduler() function continues in
350
     * scheduler_separated_stack().
351
     */
352
    context_save(&CPU->saved_context);
353
    context_set(&CPU->saved_context, FADDR(scheduler_separated_stack), (__address) CPU->stack, CPU_STACK_SIZE);
354
    context_restore(&CPU->saved_context);
355
    /* not reached */
356
}
357
 
107 decky 358
/** Scheduler stack switch wrapper
359
 *
360
 * Second part of the scheduler() function
361
 * using new stack. Handling the actual context
362
 * switch to a new thread.
363
 *
787 palkovsky 364
 * Assume THREAD->lock is held.
107 decky 365
 */
898 jermar 366
void scheduler_separated_stack(void)
1 jermar 367
{
368
    int priority;
1007 decky 369
 
227 jermar 370
    ASSERT(CPU != NULL);
1007 decky 371
 
15 jermar 372
    if (THREAD) {
898 jermar 373
        /* must be run after the switch to scheduler stack */
897 jermar 374
        after_thread_ran();
375
 
15 jermar 376
        switch (THREAD->state) {
1 jermar 377
            case Running:
125 jermar 378
            spinlock_unlock(&THREAD->lock);
379
            thread_ready(THREAD);
380
            break;
1 jermar 381
 
382
            case Exiting:
1571 jermar 383
repeat:
384
                if (THREAD->detached) {
385
                thread_destroy(THREAD);
386
            } else {
387
                /*
388
                 * The thread structure is kept allocated until somebody
389
                 * calls thread_detach() on it.
390
                 */
391
                if (!spinlock_trylock(&THREAD->join_wq.lock)) {
392
                    /*
393
                     * Avoid deadlock.
394
                     */
395
                    spinlock_unlock(&THREAD->lock);
396
                    delay(10);
397
                    spinlock_lock(&THREAD->lock);
398
                    goto repeat;
399
                }
400
                _waitq_wakeup_unsafe(&THREAD->join_wq, false);
401
                spinlock_unlock(&THREAD->join_wq.lock);
402
 
403
                THREAD->state = Undead;
404
                spinlock_unlock(&THREAD->lock);
405
            }
125 jermar 406
            break;
787 palkovsky 407
 
1 jermar 408
            case Sleeping:
125 jermar 409
            /*
410
             * Prefer the thread after it's woken up.
411
             */
413 jermar 412
            THREAD->priority = -1;
1 jermar 413
 
125 jermar 414
            /*
415
             * We need to release wq->lock which we locked in waitq_sleep().
416
             * Address of wq->lock is kept in THREAD->sleep_queue.
417
             */
418
            spinlock_unlock(&THREAD->sleep_queue->lock);
1 jermar 419
 
125 jermar 420
            /*
421
             * Check for possible requests for out-of-context invocation.
422
             */
423
            if (THREAD->call_me) {
424
                THREAD->call_me(THREAD->call_me_with);
425
                THREAD->call_me = NULL;
426
                THREAD->call_me_with = NULL;
427
            }
1 jermar 428
 
125 jermar 429
            spinlock_unlock(&THREAD->lock);
1 jermar 430
 
125 jermar 431
            break;
432
 
1 jermar 433
            default:
125 jermar 434
            /*
435
             * Entering state is unexpected.
436
             */
437
            panic("tid%d: unexpected state %s\n", THREAD->tid, thread_states[THREAD->state]);
438
            break;
1 jermar 439
        }
897 jermar 440
 
15 jermar 441
        THREAD = NULL;
1 jermar 442
    }
198 jermar 443
 
15 jermar 444
    THREAD = find_best_thread();
1 jermar 445
 
15 jermar 446
    spinlock_lock(&THREAD->lock);
413 jermar 447
    priority = THREAD->priority;
15 jermar 448
    spinlock_unlock(&THREAD->lock);
192 jermar 449
 
1 jermar 450
    relink_rq(priority);       
451
 
452
    /*
453
     * If both the old and the new task are the same, lots of work is avoided.
454
     */
15 jermar 455
    if (TASK != THREAD->task) {
703 jermar 456
        as_t *as1 = NULL;
457
        as_t *as2;
1 jermar 458
 
15 jermar 459
        if (TASK) {
460
            spinlock_lock(&TASK->lock);
703 jermar 461
            as1 = TASK->as;
15 jermar 462
            spinlock_unlock(&TASK->lock);
1 jermar 463
        }
464
 
15 jermar 465
        spinlock_lock(&THREAD->task->lock);
703 jermar 466
        as2 = THREAD->task->as;
15 jermar 467
        spinlock_unlock(&THREAD->task->lock);
1 jermar 468
 
469
        /*
703 jermar 470
         * Note that it is possible for two tasks to share one address space.
1 jermar 471
         */
703 jermar 472
        if (as1 != as2) {
1 jermar 473
            /*
703 jermar 474
             * Both tasks and address spaces are different.
1 jermar 475
             * Replace the old one with the new one.
476
             */
823 jermar 477
            as_switch(as1, as2);
1 jermar 478
        }
906 palkovsky 479
        TASK = THREAD->task;
1187 jermar 480
        before_task_runs();
1 jermar 481
    }
482
 
1380 jermar 483
    spinlock_lock(&THREAD->lock);  
15 jermar 484
    THREAD->state = Running;
1 jermar 485
 
906 palkovsky 486
#ifdef SCHEDULER_VERBOSE
1196 cejka 487
    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 488
#endif  
1 jermar 489
 
213 jermar 490
    /*
897 jermar 491
     * Some architectures provide late kernel PA2KA(identity)
492
     * mapping in a page fault handler. However, the page fault
493
     * handler uses the kernel stack of the running thread and
494
     * therefore cannot be used to map it. The kernel stack, if
495
     * necessary, is to be mapped in before_thread_runs(). This
496
     * function must be executed before the switch to the new stack.
497
     */
498
    before_thread_runs();
499
 
500
    /*
213 jermar 501
     * Copy the knowledge of CPU, TASK, THREAD and preemption counter to thread's stack.
502
     */
184 jermar 503
    the_copy(THE, (the_t *) THREAD->kstack);
504
 
15 jermar 505
    context_restore(&THREAD->saved_context);
1 jermar 506
    /* not reached */
507
}
508
 
458 decky 509
#ifdef CONFIG_SMP
107 decky 510
/** Load balancing thread
511
 *
512
 * SMP load balancing thread, supervising thread supplies
513
 * for the CPU it's wired to.
514
 *
515
 * @param arg Generic thread argument (unused).
516
 *
1 jermar 517
 */
518
void kcpulb(void *arg)
519
{
520
    thread_t *t;
783 palkovsky 521
    int count, average, i, j, k = 0;
413 jermar 522
    ipl_t ipl;
1 jermar 523
 
1576 jermar 524
    /*
525
     * Detach kcpulb as nobody will call thread_join_timeout() on it.
526
     */
527
    thread_detach(THREAD);
528
 
1 jermar 529
loop:
530
    /*
779 jermar 531
     * Work in 1s intervals.
1 jermar 532
     */
779 jermar 533
    thread_sleep(1);
1 jermar 534
 
535
not_satisfied:
536
    /*
537
     * Calculate the number of threads that will be migrated/stolen from
538
     * other CPU's. Note that situation can have changed between two
539
     * passes. Each time get the most up to date counts.
540
     */
784 palkovsky 541
    average = atomic_get(&nrdy) / config.cpu_active + 1;
783 palkovsky 542
    count = average - atomic_get(&CPU->nrdy);
1 jermar 543
 
784 palkovsky 544
    if (count <= 0)
1 jermar 545
        goto satisfied;
546
 
547
    /*
548
     * Searching least priority queues on all CPU's first and most priority queues on all CPU's last.
549
     */
550
    for (j=RQ_COUNT-1; j >= 0; j--) {
551
        for (i=0; i < config.cpu_active; i++) {
552
            link_t *l;
553
            runq_t *r;
554
            cpu_t *cpu;
555
 
556
            cpu = &cpus[(i + k) % config.cpu_active];
557
 
558
            /*
559
             * Not interested in ourselves.
560
             * Doesn't require interrupt disabling for kcpulb is X_WIRED.
561
             */
15 jermar 562
            if (CPU == cpu)
783 palkovsky 563
                continue;
564
            if (atomic_get(&cpu->nrdy) <= average)
565
                continue;
1 jermar 566
 
784 palkovsky 567
            ipl = interrupts_disable();
115 jermar 568
            r = &cpu->rq[j];
1 jermar 569
            spinlock_lock(&r->lock);
570
            if (r->n == 0) {
571
                spinlock_unlock(&r->lock);
413 jermar 572
                interrupts_restore(ipl);
1 jermar 573
                continue;
574
            }
575
 
576
            t = NULL;
577
            l = r->rq_head.prev;    /* search rq from the back */
578
            while (l != &r->rq_head) {
579
                t = list_get_instance(l, thread_t, rq_link);
580
                /*
125 jermar 581
                 * We don't want to steal CPU-wired threads neither threads already stolen.
1 jermar 582
                 * The latter prevents threads from migrating between CPU's without ever being run.
125 jermar 583
                 * We don't want to steal threads whose FPU context is still in CPU.
73 vana 584
                 */
1 jermar 585
                spinlock_lock(&t->lock);
73 vana 586
                if ( (!(t->flags & (X_WIRED | X_STOLEN))) && (!(t->fpu_context_engaged)) ) {
1 jermar 587
                    /*
588
                     * Remove t from r.
589
                     */
590
                    spinlock_unlock(&t->lock);
591
 
783 palkovsky 592
                    atomic_dec(&cpu->nrdy);
475 jermar 593
                    atomic_dec(&nrdy);
1 jermar 594
 
125 jermar 595
                    r->n--;
1 jermar 596
                    list_remove(&t->rq_link);
597
 
598
                    break;
599
                }
600
                spinlock_unlock(&t->lock);
601
                l = l->prev;
602
                t = NULL;
603
            }
604
            spinlock_unlock(&r->lock);
605
 
606
            if (t) {
607
                /*
608
                 * Ready t on local CPU
609
                 */
610
                spinlock_lock(&t->lock);
906 palkovsky 611
#ifdef KCPULB_VERBOSE
1196 cejka 612
                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 613
#endif
1 jermar 614
                t->flags |= X_STOLEN;
1115 jermar 615
                t->state = Entering;
1 jermar 616
                spinlock_unlock(&t->lock);
617
 
618
                thread_ready(t);
619
 
413 jermar 620
                interrupts_restore(ipl);
1 jermar 621
 
622
                if (--count == 0)
623
                    goto satisfied;
624
 
625
                /*
125 jermar 626
                 * We are not satisfied yet, focus on another CPU next time.
1 jermar 627
                 */
628
                k++;
629
 
630
                continue;
631
            }
413 jermar 632
            interrupts_restore(ipl);
1 jermar 633
        }
634
    }
635
 
783 palkovsky 636
    if (atomic_get(&CPU->nrdy)) {
1 jermar 637
        /*
638
         * Be a little bit light-weight and let migrated threads run.
639
         */
640
        scheduler();
779 jermar 641
    } else {
1 jermar 642
        /*
643
         * We failed to migrate a single thread.
779 jermar 644
         * Give up this turn.
1 jermar 645
         */
779 jermar 646
        goto loop;
1 jermar 647
    }
648
 
649
    goto not_satisfied;
125 jermar 650
 
1 jermar 651
satisfied:
652
    goto loop;
653
}
654
 
458 decky 655
#endif /* CONFIG_SMP */
775 palkovsky 656
 
657
 
658
/** Print information about threads & scheduler queues */
659
void sched_print_list(void)
660
{
661
    ipl_t ipl;
662
    int cpu,i;
663
    runq_t *r;
664
    thread_t *t;
665
    link_t *cur;
666
 
667
    /* We are going to mess with scheduler structures,
668
     * let's not be interrupted */
669
    ipl = interrupts_disable();
670
    for (cpu=0;cpu < config.cpu_count; cpu++) {
898 jermar 671
 
775 palkovsky 672
        if (!cpus[cpu].active)
673
            continue;
898 jermar 674
 
775 palkovsky 675
        spinlock_lock(&cpus[cpu].lock);
1221 decky 676
        printf("cpu%d: address=%p, nrdy=%ld, needs_relink=%ld\n",
1062 jermar 677
               cpus[cpu].id, &cpus[cpu], atomic_get(&cpus[cpu].nrdy), cpus[cpu].needs_relink);
775 palkovsky 678
 
679
        for (i=0; i<RQ_COUNT; i++) {
680
            r = &cpus[cpu].rq[i];
681
            spinlock_lock(&r->lock);
682
            if (!r->n) {
683
                spinlock_unlock(&r->lock);
684
                continue;
685
            }
898 jermar 686
            printf("\trq[%d]: ", i);
775 palkovsky 687
            for (cur=r->rq_head.next; cur!=&r->rq_head; cur=cur->next) {
688
                t = list_get_instance(cur, thread_t, rq_link);
689
                printf("%d(%s) ", t->tid,
690
                       thread_states[t->state]);
691
            }
692
            printf("\n");
693
            spinlock_unlock(&r->lock);
694
        }
695
        spinlock_unlock(&cpus[cpu].lock);
696
    }
697
 
698
    interrupts_restore(ipl);
699
}
1702 cejka 700
 
701
 /** @}
702
 */
703