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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
 
1757 jermar 29
/** @addtogroup genericproc
1702 cejka 30
 * @{
31
 */
32
 
1248 jermar 33
/**
1702 cejka 34
 * @file
1248 jermar 35
 * @brief   Scheduler and load balancing.
36
 *
1264 jermar 37
 * This file contains the scheduler and kcpulb kernel thread which
1248 jermar 38
 * performs load-balancing of per-CPU run queues.
39
 */
40
 
1 jermar 41
#include <proc/scheduler.h>
42
#include <proc/thread.h>
43
#include <proc/task.h>
378 jermar 44
#include <mm/frame.h>
45
#include <mm/page.h>
703 jermar 46
#include <mm/as.h>
1571 jermar 47
#include <time/delay.h>
378 jermar 48
#include <arch/asm.h>
49
#include <arch/faddr.h>
1104 jermar 50
#include <atomic.h>
378 jermar 51
#include <synch/spinlock.h>
1 jermar 52
#include <config.h>
53
#include <context.h>
54
#include <func.h>
55
#include <arch.h>
788 jermar 56
#include <adt/list.h>
68 decky 57
#include <panic.h>
1 jermar 58
#include <typedefs.h>
378 jermar 59
#include <cpu.h>
195 vana 60
#include <print.h>
227 jermar 61
#include <debug.h>
1 jermar 62
 
1187 jermar 63
static void before_task_runs(void);
64
static void before_thread_runs(void);
65
static void after_thread_ran(void);
898 jermar 66
static void scheduler_separated_stack(void);
195 vana 67
 
898 jermar 68
atomic_t nrdy;  /**< Number of ready threads in the system. */
69
 
1187 jermar 70
/** Carry out actions before new task runs. */
71
void before_task_runs(void)
72
{
73
    before_task_runs_arch();
74
}
75
 
897 jermar 76
/** Take actions before new thread runs.
107 decky 77
 *
118 jermar 78
 * Perform actions that need to be
79
 * taken before the newly selected
80
 * tread is passed control.
107 decky 81
 *
827 palkovsky 82
 * THREAD->lock is locked on entry
83
 *
107 decky 84
 */
52 vana 85
void before_thread_runs(void)
86
{
309 palkovsky 87
    before_thread_runs_arch();
906 palkovsky 88
#ifdef CONFIG_FPU_LAZY
309 palkovsky 89
    if(THREAD==CPU->fpu_owner)
90
        fpu_enable();
91
    else
92
        fpu_disable();
906 palkovsky 93
#else
309 palkovsky 94
    fpu_enable();
95
    if (THREAD->fpu_context_exists)
906 palkovsky 96
        fpu_context_restore(THREAD->saved_fpu_context);
309 palkovsky 97
    else {
906 palkovsky 98
        fpu_init();
309 palkovsky 99
        THREAD->fpu_context_exists=1;
100
    }
906 palkovsky 101
#endif
52 vana 102
}
103
 
898 jermar 104
/** Take actions after THREAD had run.
897 jermar 105
 *
106
 * Perform actions that need to be
107
 * taken after the running thread
898 jermar 108
 * had been preempted by the scheduler.
897 jermar 109
 *
110
 * THREAD->lock is locked on entry
111
 *
112
 */
113
void after_thread_ran(void)
114
{
115
    after_thread_ran_arch();
116
}
117
 
458 decky 118
#ifdef CONFIG_FPU_LAZY
309 palkovsky 119
void scheduler_fpu_lazy_request(void)
120
{
907 palkovsky 121
restart:
309 palkovsky 122
    fpu_enable();
827 palkovsky 123
    spinlock_lock(&CPU->lock);
124
 
125
    /* Save old context */
309 palkovsky 126
    if (CPU->fpu_owner != NULL) {  
827 palkovsky 127
        spinlock_lock(&CPU->fpu_owner->lock);
906 palkovsky 128
        fpu_context_save(CPU->fpu_owner->saved_fpu_context);
309 palkovsky 129
        /* don't prevent migration */
130
        CPU->fpu_owner->fpu_context_engaged=0;
827 palkovsky 131
        spinlock_unlock(&CPU->fpu_owner->lock);
907 palkovsky 132
        CPU->fpu_owner = NULL;
309 palkovsky 133
    }
827 palkovsky 134
 
135
    spinlock_lock(&THREAD->lock);
898 jermar 136
    if (THREAD->fpu_context_exists) {
906 palkovsky 137
        fpu_context_restore(THREAD->saved_fpu_context);
898 jermar 138
    } else {
906 palkovsky 139
        /* Allocate FPU context */
140
        if (!THREAD->saved_fpu_context) {
141
            /* Might sleep */
142
            spinlock_unlock(&THREAD->lock);
907 palkovsky 143
            spinlock_unlock(&CPU->lock);
1854 jermar 144
            THREAD->saved_fpu_context = slab_alloc(fpu_context_slab, 0);
907 palkovsky 145
            /* We may have switched CPUs during slab_alloc */
146
            goto restart;
906 palkovsky 147
        }
148
        fpu_init();
309 palkovsky 149
        THREAD->fpu_context_exists=1;
150
    }
151
    CPU->fpu_owner=THREAD;
152
    THREAD->fpu_context_engaged = 1;
898 jermar 153
    spinlock_unlock(&THREAD->lock);
827 palkovsky 154
 
155
    spinlock_unlock(&CPU->lock);
309 palkovsky 156
}
157
#endif
52 vana 158
 
107 decky 159
/** Initialize scheduler
160
 *
161
 * Initialize kernel scheduler.
162
 *
163
 */
1 jermar 164
void scheduler_init(void)
165
{
166
}
167
 
107 decky 168
/** Get thread to be scheduled
169
 *
170
 * Get the optimal thread to be scheduled
109 jermar 171
 * according to thread accounting and scheduler
107 decky 172
 * policy.
173
 *
174
 * @return Thread to be scheduled.
175
 *
176
 */
483 jermar 177
static thread_t *find_best_thread(void)
1 jermar 178
{
179
    thread_t *t;
180
    runq_t *r;
783 palkovsky 181
    int i;
1 jermar 182
 
227 jermar 183
    ASSERT(CPU != NULL);
184
 
1 jermar 185
loop:
413 jermar 186
    interrupts_enable();
1 jermar 187
 
783 palkovsky 188
    if (atomic_get(&CPU->nrdy) == 0) {
1 jermar 189
        /*
190
         * For there was nothing to run, the CPU goes to sleep
191
         * until a hardware interrupt or an IPI comes.
192
         * This improves energy saving and hyperthreading.
193
         */
785 jermar 194
 
195
        /*
196
         * An interrupt might occur right now and wake up a thread.
197
         * In such case, the CPU will continue to go to sleep
198
         * even though there is a runnable thread.
199
         */
200
 
1 jermar 201
         cpu_sleep();
202
         goto loop;
203
    }
204
 
413 jermar 205
    interrupts_disable();
114 jermar 206
 
898 jermar 207
    for (i = 0; i<RQ_COUNT; i++) {
15 jermar 208
        r = &CPU->rq[i];
1 jermar 209
        spinlock_lock(&r->lock);
210
        if (r->n == 0) {
211
            /*
212
             * If this queue is empty, try a lower-priority queue.
213
             */
214
            spinlock_unlock(&r->lock);
215
            continue;
216
        }
213 jermar 217
 
783 palkovsky 218
        atomic_dec(&CPU->nrdy);
475 jermar 219
        atomic_dec(&nrdy);
1 jermar 220
        r->n--;
221
 
222
        /*
223
         * Take the first thread from the queue.
224
         */
225
        t = list_get_instance(r->rq_head.next, thread_t, rq_link);
226
        list_remove(&t->rq_link);
227
 
228
        spinlock_unlock(&r->lock);
229
 
230
        spinlock_lock(&t->lock);
15 jermar 231
        t->cpu = CPU;
1 jermar 232
 
233
        t->ticks = us2ticks((i+1)*10000);
898 jermar 234
        t->priority = i;    /* correct rq index */
1 jermar 235
 
236
        /*
1854 jermar 237
         * Clear the THREAD_FLAG_STOLEN flag so that t can be migrated
238
         * when load balancing needs emerge.
1 jermar 239
         */
1854 jermar 240
        t->flags &= ~THREAD_FLAG_STOLEN;
1 jermar 241
        spinlock_unlock(&t->lock);
242
 
243
        return t;
244
    }
245
    goto loop;
246
 
247
}
248
 
107 decky 249
/** Prevent rq starvation
250
 *
251
 * Prevent low priority threads from starving in rq's.
252
 *
253
 * When the function decides to relink rq's, it reconnects
254
 * respective pointers so that in result threads with 'pri'
1708 jermar 255
 * greater or equal start are moved to a higher-priority queue.
107 decky 256
 *
257
 * @param start Threshold priority.
258
 *
1 jermar 259
 */
452 decky 260
static void relink_rq(int start)
1 jermar 261
{
262
    link_t head;
263
    runq_t *r;
264
    int i, n;
265
 
266
    list_initialize(&head);
15 jermar 267
    spinlock_lock(&CPU->lock);
268
    if (CPU->needs_relink > NEEDS_RELINK_MAX) {
1 jermar 269
        for (i = start; i<RQ_COUNT-1; i++) {
270
            /* remember and empty rq[i + 1] */
15 jermar 271
            r = &CPU->rq[i + 1];
1 jermar 272
            spinlock_lock(&r->lock);
273
            list_concat(&head, &r->rq_head);
274
            n = r->n;
275
            r->n = 0;
276
            spinlock_unlock(&r->lock);
277
 
278
            /* append rq[i + 1] to rq[i] */
15 jermar 279
            r = &CPU->rq[i];
1 jermar 280
            spinlock_lock(&r->lock);
281
            list_concat(&r->rq_head, &head);
282
            r->n += n;
283
            spinlock_unlock(&r->lock);
284
        }
15 jermar 285
        CPU->needs_relink = 0;
1 jermar 286
    }
784 palkovsky 287
    spinlock_unlock(&CPU->lock);
1 jermar 288
 
289
}
290
 
898 jermar 291
/** The scheduler
292
 *
293
 * The thread scheduling procedure.
294
 * Passes control directly to
295
 * scheduler_separated_stack().
296
 *
297
 */
298
void scheduler(void)
299
{
300
    volatile ipl_t ipl;
107 decky 301
 
898 jermar 302
    ASSERT(CPU != NULL);
303
 
304
    ipl = interrupts_disable();
305
 
306
    if (atomic_get(&haltstate))
307
        halt();
1007 decky 308
 
898 jermar 309
    if (THREAD) {
310
        spinlock_lock(&THREAD->lock);
906 palkovsky 311
#ifndef CONFIG_FPU_LAZY
312
        fpu_context_save(THREAD->saved_fpu_context);
313
#endif
898 jermar 314
        if (!context_save(&THREAD->saved_context)) {
315
            /*
316
             * This is the place where threads leave scheduler();
317
             */
318
            spinlock_unlock(&THREAD->lock);
319
            interrupts_restore(THREAD->saved_context.ipl);
1007 decky 320
 
898 jermar 321
            return;
322
        }
323
 
324
        /*
325
         * Interrupt priority level of preempted thread is recorded here
326
         * to facilitate scheduler() invocations from interrupts_disable()'d
327
         * code (e.g. waitq_sleep_timeout()).
328
         */
329
        THREAD->saved_context.ipl = ipl;
330
    }
331
 
332
    /*
333
     * Through the 'THE' structure, we keep track of THREAD, TASK, CPU, VM
334
     * and preemption counter. At this point THE could be coming either
335
     * from THREAD's or CPU's stack.
336
     */
337
    the_copy(THE, (the_t *) CPU->stack);
338
 
339
    /*
340
     * We may not keep the old stack.
341
     * Reason: If we kept the old stack and got blocked, for instance, in
342
     * find_best_thread(), the old thread could get rescheduled by another
343
     * CPU and overwrite the part of its own stack that was also used by
344
     * the scheduler on this CPU.
345
     *
346
     * Moreover, we have to bypass the compiler-generated POP sequence
347
     * which is fooled by SP being set to the very top of the stack.
348
     * Therefore the scheduler() function continues in
349
     * scheduler_separated_stack().
350
     */
351
    context_save(&CPU->saved_context);
1854 jermar 352
    context_set(&CPU->saved_context, FADDR(scheduler_separated_stack),
353
        (uintptr_t) CPU->stack, CPU_STACK_SIZE);
898 jermar 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
1854 jermar 487
    printf("cpu%d: tid %d (priority=%d,ticks=%lld,nrdy=%ld)\n",
488
        CPU->id, THREAD->tid, THREAD->priority, THREAD->ticks, atomic_get(&CPU->nrdy));
906 palkovsky 489
#endif  
1 jermar 490
 
213 jermar 491
    /*
897 jermar 492
     * Some architectures provide late kernel PA2KA(identity)
493
     * mapping in a page fault handler. However, the page fault
494
     * handler uses the kernel stack of the running thread and
495
     * therefore cannot be used to map it. The kernel stack, if
496
     * necessary, is to be mapped in before_thread_runs(). This
497
     * function must be executed before the switch to the new stack.
498
     */
499
    before_thread_runs();
500
 
501
    /*
213 jermar 502
     * Copy the knowledge of CPU, TASK, THREAD and preemption counter to thread's stack.
503
     */
184 jermar 504
    the_copy(THE, (the_t *) THREAD->kstack);
505
 
15 jermar 506
    context_restore(&THREAD->saved_context);
1 jermar 507
    /* not reached */
508
}
509
 
458 decky 510
#ifdef CONFIG_SMP
107 decky 511
/** Load balancing thread
512
 *
513
 * SMP load balancing thread, supervising thread supplies
514
 * for the CPU it's wired to.
515
 *
516
 * @param arg Generic thread argument (unused).
517
 *
1 jermar 518
 */
519
void kcpulb(void *arg)
520
{
521
    thread_t *t;
783 palkovsky 522
    int count, average, i, j, k = 0;
413 jermar 523
    ipl_t ipl;
1 jermar 524
 
1576 jermar 525
    /*
526
     * Detach kcpulb as nobody will call thread_join_timeout() on it.
527
     */
528
    thread_detach(THREAD);
529
 
1 jermar 530
loop:
531
    /*
779 jermar 532
     * Work in 1s intervals.
1 jermar 533
     */
779 jermar 534
    thread_sleep(1);
1 jermar 535
 
536
not_satisfied:
537
    /*
538
     * Calculate the number of threads that will be migrated/stolen from
539
     * other CPU's. Note that situation can have changed between two
540
     * passes. Each time get the most up to date counts.
541
     */
784 palkovsky 542
    average = atomic_get(&nrdy) / config.cpu_active + 1;
783 palkovsky 543
    count = average - atomic_get(&CPU->nrdy);
1 jermar 544
 
784 palkovsky 545
    if (count <= 0)
1 jermar 546
        goto satisfied;
547
 
548
    /*
549
     * Searching least priority queues on all CPU's first and most priority queues on all CPU's last.
550
     */
551
    for (j=RQ_COUNT-1; j >= 0; j--) {
552
        for (i=0; i < config.cpu_active; i++) {
553
            link_t *l;
554
            runq_t *r;
555
            cpu_t *cpu;
556
 
557
            cpu = &cpus[(i + k) % config.cpu_active];
558
 
559
            /*
560
             * Not interested in ourselves.
1854 jermar 561
             * Doesn't require interrupt disabling for kcpulb has THREAD_FLAG_WIRED.
1 jermar 562
             */
15 jermar 563
            if (CPU == cpu)
783 palkovsky 564
                continue;
565
            if (atomic_get(&cpu->nrdy) <= average)
566
                continue;
1 jermar 567
 
784 palkovsky 568
            ipl = interrupts_disable();
115 jermar 569
            r = &cpu->rq[j];
1 jermar 570
            spinlock_lock(&r->lock);
571
            if (r->n == 0) {
572
                spinlock_unlock(&r->lock);
413 jermar 573
                interrupts_restore(ipl);
1 jermar 574
                continue;
575
            }
576
 
577
            t = NULL;
578
            l = r->rq_head.prev;    /* search rq from the back */
579
            while (l != &r->rq_head) {
580
                t = list_get_instance(l, thread_t, rq_link);
581
                /*
1854 jermar 582
                 * We don't want to steal CPU-wired threads neither threads already
583
                 * stolen. The latter prevents threads from migrating between CPU's
584
                 * without ever being run. We don't want to steal threads whose FPU
585
                 * context is still in CPU.
73 vana 586
                 */
1 jermar 587
                spinlock_lock(&t->lock);
1854 jermar 588
                if ((!(t->flags & (THREAD_FLAG_WIRED | THREAD_FLAG_STOLEN))) &&
589
                    (!(t->fpu_context_engaged)) ) {
1 jermar 590
                    /*
591
                     * Remove t from r.
592
                     */
593
                    spinlock_unlock(&t->lock);
594
 
783 palkovsky 595
                    atomic_dec(&cpu->nrdy);
475 jermar 596
                    atomic_dec(&nrdy);
1 jermar 597
 
125 jermar 598
                    r->n--;
1 jermar 599
                    list_remove(&t->rq_link);
600
 
601
                    break;
602
                }
603
                spinlock_unlock(&t->lock);
604
                l = l->prev;
605
                t = NULL;
606
            }
607
            spinlock_unlock(&r->lock);
608
 
609
            if (t) {
610
                /*
611
                 * Ready t on local CPU
612
                 */
613
                spinlock_lock(&t->lock);
906 palkovsky 614
#ifdef KCPULB_VERBOSE
1854 jermar 615
                printf("kcpulb%d: TID %d -> cpu%d, nrdy=%ld, avg=%nd\n",
616
                    CPU->id, t->tid, CPU->id, atomic_get(&CPU->nrdy),
617
                    atomic_get(&nrdy) / config.cpu_active);
906 palkovsky 618
#endif
1854 jermar 619
                t->flags |= THREAD_FLAG_STOLEN;
1115 jermar 620
                t->state = Entering;
1 jermar 621
                spinlock_unlock(&t->lock);
622
 
623
                thread_ready(t);
624
 
413 jermar 625
                interrupts_restore(ipl);
1 jermar 626
 
627
                if (--count == 0)
628
                    goto satisfied;
629
 
630
                /*
125 jermar 631
                 * We are not satisfied yet, focus on another CPU next time.
1 jermar 632
                 */
633
                k++;
634
 
635
                continue;
636
            }
413 jermar 637
            interrupts_restore(ipl);
1 jermar 638
        }
639
    }
640
 
783 palkovsky 641
    if (atomic_get(&CPU->nrdy)) {
1 jermar 642
        /*
643
         * Be a little bit light-weight and let migrated threads run.
644
         */
645
        scheduler();
779 jermar 646
    } else {
1 jermar 647
        /*
648
         * We failed to migrate a single thread.
779 jermar 649
         * Give up this turn.
1 jermar 650
         */
779 jermar 651
        goto loop;
1 jermar 652
    }
653
 
654
    goto not_satisfied;
125 jermar 655
 
1 jermar 656
satisfied:
657
    goto loop;
658
}
659
 
458 decky 660
#endif /* CONFIG_SMP */
775 palkovsky 661
 
662
 
663
/** Print information about threads & scheduler queues */
664
void sched_print_list(void)
665
{
666
    ipl_t ipl;
667
    int cpu,i;
668
    runq_t *r;
669
    thread_t *t;
670
    link_t *cur;
671
 
672
    /* We are going to mess with scheduler structures,
673
     * let's not be interrupted */
674
    ipl = interrupts_disable();
675
    for (cpu=0;cpu < config.cpu_count; cpu++) {
898 jermar 676
 
775 palkovsky 677
        if (!cpus[cpu].active)
678
            continue;
898 jermar 679
 
775 palkovsky 680
        spinlock_lock(&cpus[cpu].lock);
1221 decky 681
        printf("cpu%d: address=%p, nrdy=%ld, needs_relink=%ld\n",
1062 jermar 682
               cpus[cpu].id, &cpus[cpu], atomic_get(&cpus[cpu].nrdy), cpus[cpu].needs_relink);
775 palkovsky 683
 
684
        for (i=0; i<RQ_COUNT; i++) {
685
            r = &cpus[cpu].rq[i];
686
            spinlock_lock(&r->lock);
687
            if (!r->n) {
688
                spinlock_unlock(&r->lock);
689
                continue;
690
            }
898 jermar 691
            printf("\trq[%d]: ", i);
775 palkovsky 692
            for (cur=r->rq_head.next; cur!=&r->rq_head; cur=cur->next) {
693
                t = list_get_instance(cur, thread_t, rq_link);
694
                printf("%d(%s) ", t->tid,
695
                       thread_states[t->state]);
696
            }
697
            printf("\n");
698
            spinlock_unlock(&r->lock);
699
        }
700
        spinlock_unlock(&cpus[cpu].lock);
701
    }
702
 
703
    interrupts_restore(ipl);
704
}
1702 cejka 705
 
1757 jermar 706
/** @}
1702 cejka 707
 */