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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
 /**
30
 * @defgroup proc Proc
31
 * @ingroup kernel
32
 * @{
33
 * @}
34
 */
35
 
36
 /** @addtogroup genericproc generic
37
 * @ingroup proc
38
 * @{
39
 */
40
 
1248 jermar 41
/**
1702 cejka 42
 * @file
1248 jermar 43
 * @brief   Scheduler and load balancing.
44
 *
1264 jermar 45
 * This file contains the scheduler and kcpulb kernel thread which
1248 jermar 46
 * performs load-balancing of per-CPU run queues.
47
 */
48
 
1 jermar 49
#include <proc/scheduler.h>
50
#include <proc/thread.h>
51
#include <proc/task.h>
378 jermar 52
#include <mm/frame.h>
53
#include <mm/page.h>
703 jermar 54
#include <mm/as.h>
1571 jermar 55
#include <time/delay.h>
378 jermar 56
#include <arch/asm.h>
57
#include <arch/faddr.h>
1104 jermar 58
#include <atomic.h>
378 jermar 59
#include <synch/spinlock.h>
1 jermar 60
#include <config.h>
61
#include <context.h>
62
#include <func.h>
63
#include <arch.h>
788 jermar 64
#include <adt/list.h>
68 decky 65
#include <panic.h>
1 jermar 66
#include <typedefs.h>
378 jermar 67
#include <cpu.h>
195 vana 68
#include <print.h>
227 jermar 69
#include <debug.h>
1 jermar 70
 
1187 jermar 71
static void before_task_runs(void);
72
static void before_thread_runs(void);
73
static void after_thread_ran(void);
898 jermar 74
static void scheduler_separated_stack(void);
195 vana 75
 
898 jermar 76
atomic_t nrdy;  /**< Number of ready threads in the system. */
77
 
1187 jermar 78
/** Carry out actions before new task runs. */
79
void before_task_runs(void)
80
{
81
    before_task_runs_arch();
82
}
83
 
897 jermar 84
/** Take actions before new thread runs.
107 decky 85
 *
118 jermar 86
 * Perform actions that need to be
87
 * taken before the newly selected
88
 * tread is passed control.
107 decky 89
 *
827 palkovsky 90
 * THREAD->lock is locked on entry
91
 *
107 decky 92
 */
52 vana 93
void before_thread_runs(void)
94
{
309 palkovsky 95
    before_thread_runs_arch();
906 palkovsky 96
#ifdef CONFIG_FPU_LAZY
309 palkovsky 97
    if(THREAD==CPU->fpu_owner)
98
        fpu_enable();
99
    else
100
        fpu_disable();
906 palkovsky 101
#else
309 palkovsky 102
    fpu_enable();
103
    if (THREAD->fpu_context_exists)
906 palkovsky 104
        fpu_context_restore(THREAD->saved_fpu_context);
309 palkovsky 105
    else {
906 palkovsky 106
        fpu_init();
309 palkovsky 107
        THREAD->fpu_context_exists=1;
108
    }
906 palkovsky 109
#endif
52 vana 110
}
111
 
898 jermar 112
/** Take actions after THREAD had run.
897 jermar 113
 *
114
 * Perform actions that need to be
115
 * taken after the running thread
898 jermar 116
 * had been preempted by the scheduler.
897 jermar 117
 *
118
 * THREAD->lock is locked on entry
119
 *
120
 */
121
void after_thread_ran(void)
122
{
123
    after_thread_ran_arch();
124
}
125
 
458 decky 126
#ifdef CONFIG_FPU_LAZY
309 palkovsky 127
void scheduler_fpu_lazy_request(void)
128
{
907 palkovsky 129
restart:
309 palkovsky 130
    fpu_enable();
827 palkovsky 131
    spinlock_lock(&CPU->lock);
132
 
133
    /* Save old context */
309 palkovsky 134
    if (CPU->fpu_owner != NULL) {  
827 palkovsky 135
        spinlock_lock(&CPU->fpu_owner->lock);
906 palkovsky 136
        fpu_context_save(CPU->fpu_owner->saved_fpu_context);
309 palkovsky 137
        /* don't prevent migration */
138
        CPU->fpu_owner->fpu_context_engaged=0;
827 palkovsky 139
        spinlock_unlock(&CPU->fpu_owner->lock);
907 palkovsky 140
        CPU->fpu_owner = NULL;
309 palkovsky 141
    }
827 palkovsky 142
 
143
    spinlock_lock(&THREAD->lock);
898 jermar 144
    if (THREAD->fpu_context_exists) {
906 palkovsky 145
        fpu_context_restore(THREAD->saved_fpu_context);
898 jermar 146
    } else {
906 palkovsky 147
        /* Allocate FPU context */
148
        if (!THREAD->saved_fpu_context) {
149
            /* Might sleep */
150
            spinlock_unlock(&THREAD->lock);
907 palkovsky 151
            spinlock_unlock(&CPU->lock);
906 palkovsky 152
            THREAD->saved_fpu_context = slab_alloc(fpu_context_slab,
153
                                   0);
907 palkovsky 154
            /* We may have switched CPUs during slab_alloc */
155
            goto restart;
906 palkovsky 156
        }
157
        fpu_init();
309 palkovsky 158
        THREAD->fpu_context_exists=1;
159
    }
160
    CPU->fpu_owner=THREAD;
161
    THREAD->fpu_context_engaged = 1;
898 jermar 162
    spinlock_unlock(&THREAD->lock);
827 palkovsky 163
 
164
    spinlock_unlock(&CPU->lock);
309 palkovsky 165
}
166
#endif
52 vana 167
 
107 decky 168
/** Initialize scheduler
169
 *
170
 * Initialize kernel scheduler.
171
 *
172
 */
1 jermar 173
void scheduler_init(void)
174
{
175
}
176
 
107 decky 177
/** Get thread to be scheduled
178
 *
179
 * Get the optimal thread to be scheduled
109 jermar 180
 * according to thread accounting and scheduler
107 decky 181
 * policy.
182
 *
183
 * @return Thread to be scheduled.
184
 *
185
 */
483 jermar 186
static thread_t *find_best_thread(void)
1 jermar 187
{
188
    thread_t *t;
189
    runq_t *r;
783 palkovsky 190
    int i;
1 jermar 191
 
227 jermar 192
    ASSERT(CPU != NULL);
193
 
1 jermar 194
loop:
413 jermar 195
    interrupts_enable();
1 jermar 196
 
783 palkovsky 197
    if (atomic_get(&CPU->nrdy) == 0) {
1 jermar 198
        /*
199
         * For there was nothing to run, the CPU goes to sleep
200
         * until a hardware interrupt or an IPI comes.
201
         * This improves energy saving and hyperthreading.
202
         */
785 jermar 203
 
204
        /*
205
         * An interrupt might occur right now and wake up a thread.
206
         * In such case, the CPU will continue to go to sleep
207
         * even though there is a runnable thread.
208
         */
209
 
1 jermar 210
         cpu_sleep();
211
         goto loop;
212
    }
213
 
413 jermar 214
    interrupts_disable();
114 jermar 215
 
898 jermar 216
    for (i = 0; i<RQ_COUNT; i++) {
15 jermar 217
        r = &CPU->rq[i];
1 jermar 218
        spinlock_lock(&r->lock);
219
        if (r->n == 0) {
220
            /*
221
             * If this queue is empty, try a lower-priority queue.
222
             */
223
            spinlock_unlock(&r->lock);
224
            continue;
225
        }
213 jermar 226
 
783 palkovsky 227
        atomic_dec(&CPU->nrdy);
475 jermar 228
        atomic_dec(&nrdy);
1 jermar 229
        r->n--;
230
 
231
        /*
232
         * Take the first thread from the queue.
233
         */
234
        t = list_get_instance(r->rq_head.next, thread_t, rq_link);
235
        list_remove(&t->rq_link);
236
 
237
        spinlock_unlock(&r->lock);
238
 
239
        spinlock_lock(&t->lock);
15 jermar 240
        t->cpu = CPU;
1 jermar 241
 
242
        t->ticks = us2ticks((i+1)*10000);
898 jermar 243
        t->priority = i;    /* correct rq index */
1 jermar 244
 
245
        /*
246
         * Clear the X_STOLEN flag so that t can be migrated when load balancing needs emerge.
247
         */
248
        t->flags &= ~X_STOLEN;
249
        spinlock_unlock(&t->lock);
250
 
251
        return t;
252
    }
253
    goto loop;
254
 
255
}
256
 
107 decky 257
/** Prevent rq starvation
258
 *
259
 * Prevent low priority threads from starving in rq's.
260
 *
261
 * When the function decides to relink rq's, it reconnects
262
 * respective pointers so that in result threads with 'pri'
1229 jermar 263
 * greater or equal @start are moved to a higher-priority queue.
107 decky 264
 *
265
 * @param start Threshold priority.
266
 *
1 jermar 267
 */
452 decky 268
static void relink_rq(int start)
1 jermar 269
{
270
    link_t head;
271
    runq_t *r;
272
    int i, n;
273
 
274
    list_initialize(&head);
15 jermar 275
    spinlock_lock(&CPU->lock);
276
    if (CPU->needs_relink > NEEDS_RELINK_MAX) {
1 jermar 277
        for (i = start; i<RQ_COUNT-1; i++) {
278
            /* remember and empty rq[i + 1] */
15 jermar 279
            r = &CPU->rq[i + 1];
1 jermar 280
            spinlock_lock(&r->lock);
281
            list_concat(&head, &r->rq_head);
282
            n = r->n;
283
            r->n = 0;
284
            spinlock_unlock(&r->lock);
285
 
286
            /* append rq[i + 1] to rq[i] */
15 jermar 287
            r = &CPU->rq[i];
1 jermar 288
            spinlock_lock(&r->lock);
289
            list_concat(&r->rq_head, &head);
290
            r->n += n;
291
            spinlock_unlock(&r->lock);
292
        }
15 jermar 293
        CPU->needs_relink = 0;
1 jermar 294
    }
784 palkovsky 295
    spinlock_unlock(&CPU->lock);
1 jermar 296
 
297
}
298
 
898 jermar 299
/** The scheduler
300
 *
301
 * The thread scheduling procedure.
302
 * Passes control directly to
303
 * scheduler_separated_stack().
304
 *
305
 */
306
void scheduler(void)
307
{
308
    volatile ipl_t ipl;
107 decky 309
 
898 jermar 310
    ASSERT(CPU != NULL);
311
 
312
    ipl = interrupts_disable();
313
 
314
    if (atomic_get(&haltstate))
315
        halt();
1007 decky 316
 
898 jermar 317
    if (THREAD) {
318
        spinlock_lock(&THREAD->lock);
906 palkovsky 319
#ifndef CONFIG_FPU_LAZY
320
        fpu_context_save(THREAD->saved_fpu_context);
321
#endif
898 jermar 322
        if (!context_save(&THREAD->saved_context)) {
323
            /*
324
             * This is the place where threads leave scheduler();
325
             */
326
            spinlock_unlock(&THREAD->lock);
327
            interrupts_restore(THREAD->saved_context.ipl);
1007 decky 328
 
898 jermar 329
            return;
330
        }
331
 
332
        /*
333
         * Interrupt priority level of preempted thread is recorded here
334
         * to facilitate scheduler() invocations from interrupts_disable()'d
335
         * code (e.g. waitq_sleep_timeout()).
336
         */
337
        THREAD->saved_context.ipl = ipl;
338
    }
339
 
340
    /*
341
     * Through the 'THE' structure, we keep track of THREAD, TASK, CPU, VM
342
     * and preemption counter. At this point THE could be coming either
343
     * from THREAD's or CPU's stack.
344
     */
345
    the_copy(THE, (the_t *) CPU->stack);
346
 
347
    /*
348
     * We may not keep the old stack.
349
     * Reason: If we kept the old stack and got blocked, for instance, in
350
     * find_best_thread(), the old thread could get rescheduled by another
351
     * CPU and overwrite the part of its own stack that was also used by
352
     * the scheduler on this CPU.
353
     *
354
     * Moreover, we have to bypass the compiler-generated POP sequence
355
     * which is fooled by SP being set to the very top of the stack.
356
     * Therefore the scheduler() function continues in
357
     * scheduler_separated_stack().
358
     */
359
    context_save(&CPU->saved_context);
360
    context_set(&CPU->saved_context, FADDR(scheduler_separated_stack), (__address) CPU->stack, CPU_STACK_SIZE);
361
    context_restore(&CPU->saved_context);
362
    /* not reached */
363
}
364
 
107 decky 365
/** Scheduler stack switch wrapper
366
 *
367
 * Second part of the scheduler() function
368
 * using new stack. Handling the actual context
369
 * switch to a new thread.
370
 *
787 palkovsky 371
 * Assume THREAD->lock is held.
107 decky 372
 */
898 jermar 373
void scheduler_separated_stack(void)
1 jermar 374
{
375
    int priority;
1007 decky 376
 
227 jermar 377
    ASSERT(CPU != NULL);
1007 decky 378
 
15 jermar 379
    if (THREAD) {
898 jermar 380
        /* must be run after the switch to scheduler stack */
897 jermar 381
        after_thread_ran();
382
 
15 jermar 383
        switch (THREAD->state) {
1 jermar 384
            case Running:
125 jermar 385
            spinlock_unlock(&THREAD->lock);
386
            thread_ready(THREAD);
387
            break;
1 jermar 388
 
389
            case Exiting:
1571 jermar 390
repeat:
391
                if (THREAD->detached) {
392
                thread_destroy(THREAD);
393
            } else {
394
                /*
395
                 * The thread structure is kept allocated until somebody
396
                 * calls thread_detach() on it.
397
                 */
398
                if (!spinlock_trylock(&THREAD->join_wq.lock)) {
399
                    /*
400
                     * Avoid deadlock.
401
                     */
402
                    spinlock_unlock(&THREAD->lock);
403
                    delay(10);
404
                    spinlock_lock(&THREAD->lock);
405
                    goto repeat;
406
                }
407
                _waitq_wakeup_unsafe(&THREAD->join_wq, false);
408
                spinlock_unlock(&THREAD->join_wq.lock);
409
 
410
                THREAD->state = Undead;
411
                spinlock_unlock(&THREAD->lock);
412
            }
125 jermar 413
            break;
787 palkovsky 414
 
1 jermar 415
            case Sleeping:
125 jermar 416
            /*
417
             * Prefer the thread after it's woken up.
418
             */
413 jermar 419
            THREAD->priority = -1;
1 jermar 420
 
125 jermar 421
            /*
422
             * We need to release wq->lock which we locked in waitq_sleep().
423
             * Address of wq->lock is kept in THREAD->sleep_queue.
424
             */
425
            spinlock_unlock(&THREAD->sleep_queue->lock);
1 jermar 426
 
125 jermar 427
            /*
428
             * Check for possible requests for out-of-context invocation.
429
             */
430
            if (THREAD->call_me) {
431
                THREAD->call_me(THREAD->call_me_with);
432
                THREAD->call_me = NULL;
433
                THREAD->call_me_with = NULL;
434
            }
1 jermar 435
 
125 jermar 436
            spinlock_unlock(&THREAD->lock);
1 jermar 437
 
125 jermar 438
            break;
439
 
1 jermar 440
            default:
125 jermar 441
            /*
442
             * Entering state is unexpected.
443
             */
444
            panic("tid%d: unexpected state %s\n", THREAD->tid, thread_states[THREAD->state]);
445
            break;
1 jermar 446
        }
897 jermar 447
 
15 jermar 448
        THREAD = NULL;
1 jermar 449
    }
198 jermar 450
 
15 jermar 451
    THREAD = find_best_thread();
1 jermar 452
 
15 jermar 453
    spinlock_lock(&THREAD->lock);
413 jermar 454
    priority = THREAD->priority;
15 jermar 455
    spinlock_unlock(&THREAD->lock);
192 jermar 456
 
1 jermar 457
    relink_rq(priority);       
458
 
459
    /*
460
     * If both the old and the new task are the same, lots of work is avoided.
461
     */
15 jermar 462
    if (TASK != THREAD->task) {
703 jermar 463
        as_t *as1 = NULL;
464
        as_t *as2;
1 jermar 465
 
15 jermar 466
        if (TASK) {
467
            spinlock_lock(&TASK->lock);
703 jermar 468
            as1 = TASK->as;
15 jermar 469
            spinlock_unlock(&TASK->lock);
1 jermar 470
        }
471
 
15 jermar 472
        spinlock_lock(&THREAD->task->lock);
703 jermar 473
        as2 = THREAD->task->as;
15 jermar 474
        spinlock_unlock(&THREAD->task->lock);
1 jermar 475
 
476
        /*
703 jermar 477
         * Note that it is possible for two tasks to share one address space.
1 jermar 478
         */
703 jermar 479
        if (as1 != as2) {
1 jermar 480
            /*
703 jermar 481
             * Both tasks and address spaces are different.
1 jermar 482
             * Replace the old one with the new one.
483
             */
823 jermar 484
            as_switch(as1, as2);
1 jermar 485
        }
906 palkovsky 486
        TASK = THREAD->task;
1187 jermar 487
        before_task_runs();
1 jermar 488
    }
489
 
1380 jermar 490
    spinlock_lock(&THREAD->lock);  
15 jermar 491
    THREAD->state = Running;
1 jermar 492
 
906 palkovsky 493
#ifdef SCHEDULER_VERBOSE
1196 cejka 494
    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 495
#endif  
1 jermar 496
 
213 jermar 497
    /*
897 jermar 498
     * Some architectures provide late kernel PA2KA(identity)
499
     * mapping in a page fault handler. However, the page fault
500
     * handler uses the kernel stack of the running thread and
501
     * therefore cannot be used to map it. The kernel stack, if
502
     * necessary, is to be mapped in before_thread_runs(). This
503
     * function must be executed before the switch to the new stack.
504
     */
505
    before_thread_runs();
506
 
507
    /*
213 jermar 508
     * Copy the knowledge of CPU, TASK, THREAD and preemption counter to thread's stack.
509
     */
184 jermar 510
    the_copy(THE, (the_t *) THREAD->kstack);
511
 
15 jermar 512
    context_restore(&THREAD->saved_context);
1 jermar 513
    /* not reached */
514
}
515
 
458 decky 516
#ifdef CONFIG_SMP
107 decky 517
/** Load balancing thread
518
 *
519
 * SMP load balancing thread, supervising thread supplies
520
 * for the CPU it's wired to.
521
 *
522
 * @param arg Generic thread argument (unused).
523
 *
1 jermar 524
 */
525
void kcpulb(void *arg)
526
{
527
    thread_t *t;
783 palkovsky 528
    int count, average, i, j, k = 0;
413 jermar 529
    ipl_t ipl;
1 jermar 530
 
1576 jermar 531
    /*
532
     * Detach kcpulb as nobody will call thread_join_timeout() on it.
533
     */
534
    thread_detach(THREAD);
535
 
1 jermar 536
loop:
537
    /*
779 jermar 538
     * Work in 1s intervals.
1 jermar 539
     */
779 jermar 540
    thread_sleep(1);
1 jermar 541
 
542
not_satisfied:
543
    /*
544
     * Calculate the number of threads that will be migrated/stolen from
545
     * other CPU's. Note that situation can have changed between two
546
     * passes. Each time get the most up to date counts.
547
     */
784 palkovsky 548
    average = atomic_get(&nrdy) / config.cpu_active + 1;
783 palkovsky 549
    count = average - atomic_get(&CPU->nrdy);
1 jermar 550
 
784 palkovsky 551
    if (count <= 0)
1 jermar 552
        goto satisfied;
553
 
554
    /*
555
     * Searching least priority queues on all CPU's first and most priority queues on all CPU's last.
556
     */
557
    for (j=RQ_COUNT-1; j >= 0; j--) {
558
        for (i=0; i < config.cpu_active; i++) {
559
            link_t *l;
560
            runq_t *r;
561
            cpu_t *cpu;
562
 
563
            cpu = &cpus[(i + k) % config.cpu_active];
564
 
565
            /*
566
             * Not interested in ourselves.
567
             * Doesn't require interrupt disabling for kcpulb is X_WIRED.
568
             */
15 jermar 569
            if (CPU == cpu)
783 palkovsky 570
                continue;
571
            if (atomic_get(&cpu->nrdy) <= average)
572
                continue;
1 jermar 573
 
784 palkovsky 574
            ipl = interrupts_disable();
115 jermar 575
            r = &cpu->rq[j];
1 jermar 576
            spinlock_lock(&r->lock);
577
            if (r->n == 0) {
578
                spinlock_unlock(&r->lock);
413 jermar 579
                interrupts_restore(ipl);
1 jermar 580
                continue;
581
            }
582
 
583
            t = NULL;
584
            l = r->rq_head.prev;    /* search rq from the back */
585
            while (l != &r->rq_head) {
586
                t = list_get_instance(l, thread_t, rq_link);
587
                /*
125 jermar 588
                 * We don't want to steal CPU-wired threads neither threads already stolen.
1 jermar 589
                 * The latter prevents threads from migrating between CPU's without ever being run.
125 jermar 590
                 * We don't want to steal threads whose FPU context is still in CPU.
73 vana 591
                 */
1 jermar 592
                spinlock_lock(&t->lock);
73 vana 593
                if ( (!(t->flags & (X_WIRED | X_STOLEN))) && (!(t->fpu_context_engaged)) ) {
1 jermar 594
                    /*
595
                     * Remove t from r.
596
                     */
597
                    spinlock_unlock(&t->lock);
598
 
783 palkovsky 599
                    atomic_dec(&cpu->nrdy);
475 jermar 600
                    atomic_dec(&nrdy);
1 jermar 601
 
125 jermar 602
                    r->n--;
1 jermar 603
                    list_remove(&t->rq_link);
604
 
605
                    break;
606
                }
607
                spinlock_unlock(&t->lock);
608
                l = l->prev;
609
                t = NULL;
610
            }
611
            spinlock_unlock(&r->lock);
612
 
613
            if (t) {
614
                /*
615
                 * Ready t on local CPU
616
                 */
617
                spinlock_lock(&t->lock);
906 palkovsky 618
#ifdef KCPULB_VERBOSE
1196 cejka 619
                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 620
#endif
1 jermar 621
                t->flags |= X_STOLEN;
1115 jermar 622
                t->state = Entering;
1 jermar 623
                spinlock_unlock(&t->lock);
624
 
625
                thread_ready(t);
626
 
413 jermar 627
                interrupts_restore(ipl);
1 jermar 628
 
629
                if (--count == 0)
630
                    goto satisfied;
631
 
632
                /*
125 jermar 633
                 * We are not satisfied yet, focus on another CPU next time.
1 jermar 634
                 */
635
                k++;
636
 
637
                continue;
638
            }
413 jermar 639
            interrupts_restore(ipl);
1 jermar 640
        }
641
    }
642
 
783 palkovsky 643
    if (atomic_get(&CPU->nrdy)) {
1 jermar 644
        /*
645
         * Be a little bit light-weight and let migrated threads run.
646
         */
647
        scheduler();
779 jermar 648
    } else {
1 jermar 649
        /*
650
         * We failed to migrate a single thread.
779 jermar 651
         * Give up this turn.
1 jermar 652
         */
779 jermar 653
        goto loop;
1 jermar 654
    }
655
 
656
    goto not_satisfied;
125 jermar 657
 
1 jermar 658
satisfied:
659
    goto loop;
660
}
661
 
458 decky 662
#endif /* CONFIG_SMP */
775 palkovsky 663
 
664
 
665
/** Print information about threads & scheduler queues */
666
void sched_print_list(void)
667
{
668
    ipl_t ipl;
669
    int cpu,i;
670
    runq_t *r;
671
    thread_t *t;
672
    link_t *cur;
673
 
674
    /* We are going to mess with scheduler structures,
675
     * let's not be interrupted */
676
    ipl = interrupts_disable();
677
    for (cpu=0;cpu < config.cpu_count; cpu++) {
898 jermar 678
 
775 palkovsky 679
        if (!cpus[cpu].active)
680
            continue;
898 jermar 681
 
775 palkovsky 682
        spinlock_lock(&cpus[cpu].lock);
1221 decky 683
        printf("cpu%d: address=%p, nrdy=%ld, needs_relink=%ld\n",
1062 jermar 684
               cpus[cpu].id, &cpus[cpu], atomic_get(&cpus[cpu].nrdy), cpus[cpu].needs_relink);
775 palkovsky 685
 
686
        for (i=0; i<RQ_COUNT; i++) {
687
            r = &cpus[cpu].rq[i];
688
            spinlock_lock(&r->lock);
689
            if (!r->n) {
690
                spinlock_unlock(&r->lock);
691
                continue;
692
            }
898 jermar 693
            printf("\trq[%d]: ", i);
775 palkovsky 694
            for (cur=r->rq_head.next; cur!=&r->rq_head; cur=cur->next) {
695
                t = list_get_instance(cur, thread_t, rq_link);
696
                printf("%d(%s) ", t->tid,
697
                       thread_states[t->state]);
698
            }
699
            printf("\n");
700
            spinlock_unlock(&r->lock);
701
        }
702
        spinlock_unlock(&cpus[cpu].lock);
703
    }
704
 
705
    interrupts_restore(ipl);
706
}
1702 cejka 707
 
708
 /** @}
709
 */
710