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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);
906 palkovsky 144
            THREAD->saved_fpu_context = slab_alloc(fpu_context_slab,
145
                                   0);
907 palkovsky 146
            /* We may have switched CPUs during slab_alloc */
147
            goto restart;
906 palkovsky 148
        }
149
        fpu_init();
309 palkovsky 150
        THREAD->fpu_context_exists=1;
151
    }
152
    CPU->fpu_owner=THREAD;
153
    THREAD->fpu_context_engaged = 1;
898 jermar 154
    spinlock_unlock(&THREAD->lock);
827 palkovsky 155
 
156
    spinlock_unlock(&CPU->lock);
309 palkovsky 157
}
158
#endif
52 vana 159
 
107 decky 160
/** Initialize scheduler
161
 *
162
 * Initialize kernel scheduler.
163
 *
164
 */
1 jermar 165
void scheduler_init(void)
166
{
167
}
168
 
107 decky 169
/** Get thread to be scheduled
170
 *
171
 * Get the optimal thread to be scheduled
109 jermar 172
 * according to thread accounting and scheduler
107 decky 173
 * policy.
174
 *
175
 * @return Thread to be scheduled.
176
 *
177
 */
483 jermar 178
static thread_t *find_best_thread(void)
1 jermar 179
{
180
    thread_t *t;
181
    runq_t *r;
783 palkovsky 182
    int i;
1 jermar 183
 
227 jermar 184
    ASSERT(CPU != NULL);
185
 
1 jermar 186
loop:
413 jermar 187
    interrupts_enable();
1 jermar 188
 
783 palkovsky 189
    if (atomic_get(&CPU->nrdy) == 0) {
1 jermar 190
        /*
191
         * For there was nothing to run, the CPU goes to sleep
192
         * until a hardware interrupt or an IPI comes.
193
         * This improves energy saving and hyperthreading.
194
         */
785 jermar 195
 
196
        /*
197
         * An interrupt might occur right now and wake up a thread.
198
         * In such case, the CPU will continue to go to sleep
199
         * even though there is a runnable thread.
200
         */
201
 
1 jermar 202
         cpu_sleep();
203
         goto loop;
204
    }
205
 
413 jermar 206
    interrupts_disable();
114 jermar 207
 
898 jermar 208
    for (i = 0; i<RQ_COUNT; i++) {
15 jermar 209
        r = &CPU->rq[i];
1 jermar 210
        spinlock_lock(&r->lock);
211
        if (r->n == 0) {
212
            /*
213
             * If this queue is empty, try a lower-priority queue.
214
             */
215
            spinlock_unlock(&r->lock);
216
            continue;
217
        }
213 jermar 218
 
783 palkovsky 219
        atomic_dec(&CPU->nrdy);
475 jermar 220
        atomic_dec(&nrdy);
1 jermar 221
        r->n--;
222
 
223
        /*
224
         * Take the first thread from the queue.
225
         */
226
        t = list_get_instance(r->rq_head.next, thread_t, rq_link);
227
        list_remove(&t->rq_link);
228
 
229
        spinlock_unlock(&r->lock);
230
 
231
        spinlock_lock(&t->lock);
15 jermar 232
        t->cpu = CPU;
1 jermar 233
 
234
        t->ticks = us2ticks((i+1)*10000);
898 jermar 235
        t->priority = i;    /* correct rq index */
1 jermar 236
 
237
        /*
238
         * Clear the X_STOLEN flag so that t can be migrated when load balancing needs emerge.
239
         */
240
        t->flags &= ~X_STOLEN;
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);
352
    context_set(&CPU->saved_context, FADDR(scheduler_separated_stack), (__address) CPU->stack, CPU_STACK_SIZE);
353
    context_restore(&CPU->saved_context);
354
    /* not reached */
355
}
356
 
107 decky 357
/** Scheduler stack switch wrapper
358
 *
359
 * Second part of the scheduler() function
360
 * using new stack. Handling the actual context
361
 * switch to a new thread.
362
 *
787 palkovsky 363
 * Assume THREAD->lock is held.
107 decky 364
 */
898 jermar 365
void scheduler_separated_stack(void)
1 jermar 366
{
367
    int priority;
1007 decky 368
 
227 jermar 369
    ASSERT(CPU != NULL);
1007 decky 370
 
15 jermar 371
    if (THREAD) {
898 jermar 372
        /* must be run after the switch to scheduler stack */
897 jermar 373
        after_thread_ran();
374
 
15 jermar 375
        switch (THREAD->state) {
1 jermar 376
            case Running:
125 jermar 377
            spinlock_unlock(&THREAD->lock);
378
            thread_ready(THREAD);
379
            break;
1 jermar 380
 
381
            case Exiting:
1571 jermar 382
repeat:
383
                if (THREAD->detached) {
384
                thread_destroy(THREAD);
385
            } else {
386
                /*
387
                 * The thread structure is kept allocated until somebody
388
                 * calls thread_detach() on it.
389
                 */
390
                if (!spinlock_trylock(&THREAD->join_wq.lock)) {
391
                    /*
392
                     * Avoid deadlock.
393
                     */
394
                    spinlock_unlock(&THREAD->lock);
395
                    delay(10);
396
                    spinlock_lock(&THREAD->lock);
397
                    goto repeat;
398
                }
399
                _waitq_wakeup_unsafe(&THREAD->join_wq, false);
400
                spinlock_unlock(&THREAD->join_wq.lock);
401
 
402
                THREAD->state = Undead;
403
                spinlock_unlock(&THREAD->lock);
404
            }
125 jermar 405
            break;
787 palkovsky 406
 
1 jermar 407
            case Sleeping:
125 jermar 408
            /*
409
             * Prefer the thread after it's woken up.
410
             */
413 jermar 411
            THREAD->priority = -1;
1 jermar 412
 
125 jermar 413
            /*
414
             * We need to release wq->lock which we locked in waitq_sleep().
415
             * Address of wq->lock is kept in THREAD->sleep_queue.
416
             */
417
            spinlock_unlock(&THREAD->sleep_queue->lock);
1 jermar 418
 
125 jermar 419
            /*
420
             * Check for possible requests for out-of-context invocation.
421
             */
422
            if (THREAD->call_me) {
423
                THREAD->call_me(THREAD->call_me_with);
424
                THREAD->call_me = NULL;
425
                THREAD->call_me_with = NULL;
426
            }
1 jermar 427
 
125 jermar 428
            spinlock_unlock(&THREAD->lock);
1 jermar 429
 
125 jermar 430
            break;
431
 
1 jermar 432
            default:
125 jermar 433
            /*
434
             * Entering state is unexpected.
435
             */
436
            panic("tid%d: unexpected state %s\n", THREAD->tid, thread_states[THREAD->state]);
437
            break;
1 jermar 438
        }
897 jermar 439
 
15 jermar 440
        THREAD = NULL;
1 jermar 441
    }
198 jermar 442
 
15 jermar 443
    THREAD = find_best_thread();
1 jermar 444
 
15 jermar 445
    spinlock_lock(&THREAD->lock);
413 jermar 446
    priority = THREAD->priority;
15 jermar 447
    spinlock_unlock(&THREAD->lock);
192 jermar 448
 
1 jermar 449
    relink_rq(priority);       
450
 
451
    /*
452
     * If both the old and the new task are the same, lots of work is avoided.
453
     */
15 jermar 454
    if (TASK != THREAD->task) {
703 jermar 455
        as_t *as1 = NULL;
456
        as_t *as2;
1 jermar 457
 
15 jermar 458
        if (TASK) {
459
            spinlock_lock(&TASK->lock);
703 jermar 460
            as1 = TASK->as;
15 jermar 461
            spinlock_unlock(&TASK->lock);
1 jermar 462
        }
463
 
15 jermar 464
        spinlock_lock(&THREAD->task->lock);
703 jermar 465
        as2 = THREAD->task->as;
15 jermar 466
        spinlock_unlock(&THREAD->task->lock);
1 jermar 467
 
468
        /*
703 jermar 469
         * Note that it is possible for two tasks to share one address space.
1 jermar 470
         */
703 jermar 471
        if (as1 != as2) {
1 jermar 472
            /*
703 jermar 473
             * Both tasks and address spaces are different.
1 jermar 474
             * Replace the old one with the new one.
475
             */
823 jermar 476
            as_switch(as1, as2);
1 jermar 477
        }
906 palkovsky 478
        TASK = THREAD->task;
1187 jermar 479
        before_task_runs();
1 jermar 480
    }
481
 
1380 jermar 482
    spinlock_lock(&THREAD->lock);  
15 jermar 483
    THREAD->state = Running;
1 jermar 484
 
906 palkovsky 485
#ifdef SCHEDULER_VERBOSE
1196 cejka 486
    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 487
#endif  
1 jermar 488
 
213 jermar 489
    /*
897 jermar 490
     * Some architectures provide late kernel PA2KA(identity)
491
     * mapping in a page fault handler. However, the page fault
492
     * handler uses the kernel stack of the running thread and
493
     * therefore cannot be used to map it. The kernel stack, if
494
     * necessary, is to be mapped in before_thread_runs(). This
495
     * function must be executed before the switch to the new stack.
496
     */
497
    before_thread_runs();
498
 
499
    /*
213 jermar 500
     * Copy the knowledge of CPU, TASK, THREAD and preemption counter to thread's stack.
501
     */
184 jermar 502
    the_copy(THE, (the_t *) THREAD->kstack);
503
 
15 jermar 504
    context_restore(&THREAD->saved_context);
1 jermar 505
    /* not reached */
506
}
507
 
458 decky 508
#ifdef CONFIG_SMP
107 decky 509
/** Load balancing thread
510
 *
511
 * SMP load balancing thread, supervising thread supplies
512
 * for the CPU it's wired to.
513
 *
514
 * @param arg Generic thread argument (unused).
515
 *
1 jermar 516
 */
517
void kcpulb(void *arg)
518
{
519
    thread_t *t;
783 palkovsky 520
    int count, average, i, j, k = 0;
413 jermar 521
    ipl_t ipl;
1 jermar 522
 
1576 jermar 523
    /*
524
     * Detach kcpulb as nobody will call thread_join_timeout() on it.
525
     */
526
    thread_detach(THREAD);
527
 
1 jermar 528
loop:
529
    /*
779 jermar 530
     * Work in 1s intervals.
1 jermar 531
     */
779 jermar 532
    thread_sleep(1);
1 jermar 533
 
534
not_satisfied:
535
    /*
536
     * Calculate the number of threads that will be migrated/stolen from
537
     * other CPU's. Note that situation can have changed between two
538
     * passes. Each time get the most up to date counts.
539
     */
784 palkovsky 540
    average = atomic_get(&nrdy) / config.cpu_active + 1;
783 palkovsky 541
    count = average - atomic_get(&CPU->nrdy);
1 jermar 542
 
784 palkovsky 543
    if (count <= 0)
1 jermar 544
        goto satisfied;
545
 
546
    /*
547
     * Searching least priority queues on all CPU's first and most priority queues on all CPU's last.
548
     */
549
    for (j=RQ_COUNT-1; j >= 0; j--) {
550
        for (i=0; i < config.cpu_active; i++) {
551
            link_t *l;
552
            runq_t *r;
553
            cpu_t *cpu;
554
 
555
            cpu = &cpus[(i + k) % config.cpu_active];
556
 
557
            /*
558
             * Not interested in ourselves.
559
             * Doesn't require interrupt disabling for kcpulb is X_WIRED.
560
             */
15 jermar 561
            if (CPU == cpu)
783 palkovsky 562
                continue;
563
            if (atomic_get(&cpu->nrdy) <= average)
564
                continue;
1 jermar 565
 
784 palkovsky 566
            ipl = interrupts_disable();
115 jermar 567
            r = &cpu->rq[j];
1 jermar 568
            spinlock_lock(&r->lock);
569
            if (r->n == 0) {
570
                spinlock_unlock(&r->lock);
413 jermar 571
                interrupts_restore(ipl);
1 jermar 572
                continue;
573
            }
574
 
575
            t = NULL;
576
            l = r->rq_head.prev;    /* search rq from the back */
577
            while (l != &r->rq_head) {
578
                t = list_get_instance(l, thread_t, rq_link);
579
                /*
125 jermar 580
                 * We don't want to steal CPU-wired threads neither threads already stolen.
1 jermar 581
                 * The latter prevents threads from migrating between CPU's without ever being run.
125 jermar 582
                 * We don't want to steal threads whose FPU context is still in CPU.
73 vana 583
                 */
1 jermar 584
                spinlock_lock(&t->lock);
73 vana 585
                if ( (!(t->flags & (X_WIRED | X_STOLEN))) && (!(t->fpu_context_engaged)) ) {
1 jermar 586
                    /*
587
                     * Remove t from r.
588
                     */
589
                    spinlock_unlock(&t->lock);
590
 
783 palkovsky 591
                    atomic_dec(&cpu->nrdy);
475 jermar 592
                    atomic_dec(&nrdy);
1 jermar 593
 
125 jermar 594
                    r->n--;
1 jermar 595
                    list_remove(&t->rq_link);
596
 
597
                    break;
598
                }
599
                spinlock_unlock(&t->lock);
600
                l = l->prev;
601
                t = NULL;
602
            }
603
            spinlock_unlock(&r->lock);
604
 
605
            if (t) {
606
                /*
607
                 * Ready t on local CPU
608
                 */
609
                spinlock_lock(&t->lock);
906 palkovsky 610
#ifdef KCPULB_VERBOSE
1196 cejka 611
                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 612
#endif
1 jermar 613
                t->flags |= X_STOLEN;
1115 jermar 614
                t->state = Entering;
1 jermar 615
                spinlock_unlock(&t->lock);
616
 
617
                thread_ready(t);
618
 
413 jermar 619
                interrupts_restore(ipl);
1 jermar 620
 
621
                if (--count == 0)
622
                    goto satisfied;
623
 
624
                /*
125 jermar 625
                 * We are not satisfied yet, focus on another CPU next time.
1 jermar 626
                 */
627
                k++;
628
 
629
                continue;
630
            }
413 jermar 631
            interrupts_restore(ipl);
1 jermar 632
        }
633
    }
634
 
783 palkovsky 635
    if (atomic_get(&CPU->nrdy)) {
1 jermar 636
        /*
637
         * Be a little bit light-weight and let migrated threads run.
638
         */
639
        scheduler();
779 jermar 640
    } else {
1 jermar 641
        /*
642
         * We failed to migrate a single thread.
779 jermar 643
         * Give up this turn.
1 jermar 644
         */
779 jermar 645
        goto loop;
1 jermar 646
    }
647
 
648
    goto not_satisfied;
125 jermar 649
 
1 jermar 650
satisfied:
651
    goto loop;
652
}
653
 
458 decky 654
#endif /* CONFIG_SMP */
775 palkovsky 655
 
656
 
657
/** Print information about threads & scheduler queues */
658
void sched_print_list(void)
659
{
660
    ipl_t ipl;
661
    int cpu,i;
662
    runq_t *r;
663
    thread_t *t;
664
    link_t *cur;
665
 
666
    /* We are going to mess with scheduler structures,
667
     * let's not be interrupted */
668
    ipl = interrupts_disable();
669
    for (cpu=0;cpu < config.cpu_count; cpu++) {
898 jermar 670
 
775 palkovsky 671
        if (!cpus[cpu].active)
672
            continue;
898 jermar 673
 
775 palkovsky 674
        spinlock_lock(&cpus[cpu].lock);
1221 decky 675
        printf("cpu%d: address=%p, nrdy=%ld, needs_relink=%ld\n",
1062 jermar 676
               cpus[cpu].id, &cpus[cpu], atomic_get(&cpus[cpu].nrdy), cpus[cpu].needs_relink);
775 palkovsky 677
 
678
        for (i=0; i<RQ_COUNT; i++) {
679
            r = &cpus[cpu].rq[i];
680
            spinlock_lock(&r->lock);
681
            if (!r->n) {
682
                spinlock_unlock(&r->lock);
683
                continue;
684
            }
898 jermar 685
            printf("\trq[%d]: ", i);
775 palkovsky 686
            for (cur=r->rq_head.next; cur!=&r->rq_head; cur=cur->next) {
687
                t = list_get_instance(cur, thread_t, rq_link);
688
                printf("%d(%s) ", t->tid,
689
                       thread_states[t->state]);
690
            }
691
            printf("\n");
692
            spinlock_unlock(&r->lock);
693
        }
694
        spinlock_unlock(&cpus[cpu].lock);
695
    }
696
 
697
    interrupts_restore(ipl);
698
}
1702 cejka 699
 
1757 jermar 700
/** @}
1702 cejka 701
 */