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1 jermar 1
/*
2071 jermar 2
 * Copyright (c) 2001-2007 Jakub Jermar
1 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>
2089 decky 47
#include <time/timeout.h>
1571 jermar 48
#include <time/delay.h>
378 jermar 49
#include <arch/asm.h>
50
#include <arch/faddr.h>
2030 decky 51
#include <arch/cycle.h>
1104 jermar 52
#include <atomic.h>
378 jermar 53
#include <synch/spinlock.h>
1 jermar 54
#include <config.h>
55
#include <context.h>
2089 decky 56
#include <fpu_context.h>
1 jermar 57
#include <func.h>
58
#include <arch.h>
788 jermar 59
#include <adt/list.h>
68 decky 60
#include <panic.h>
378 jermar 61
#include <cpu.h>
195 vana 62
#include <print.h>
227 jermar 63
#include <debug.h>
1 jermar 64
 
1187 jermar 65
static void before_task_runs(void);
66
static void before_thread_runs(void);
67
static void after_thread_ran(void);
898 jermar 68
static void scheduler_separated_stack(void);
195 vana 69
 
898 jermar 70
atomic_t nrdy;  /**< Number of ready threads in the system. */
71
 
1187 jermar 72
/** Carry out actions before new task runs. */
73
void before_task_runs(void)
74
{
75
    before_task_runs_arch();
76
}
77
 
897 jermar 78
/** Take actions before new thread runs.
107 decky 79
 *
118 jermar 80
 * Perform actions that need to be
81
 * taken before the newly selected
82
 * tread is passed control.
107 decky 83
 *
827 palkovsky 84
 * THREAD->lock is locked on entry
85
 *
107 decky 86
 */
52 vana 87
void before_thread_runs(void)
88
{
309 palkovsky 89
    before_thread_runs_arch();
906 palkovsky 90
#ifdef CONFIG_FPU_LAZY
1882 jermar 91
    if(THREAD == CPU->fpu_owner)
309 palkovsky 92
        fpu_enable();
93
    else
94
        fpu_disable();
906 palkovsky 95
#else
309 palkovsky 96
    fpu_enable();
97
    if (THREAD->fpu_context_exists)
906 palkovsky 98
        fpu_context_restore(THREAD->saved_fpu_context);
309 palkovsky 99
    else {
906 palkovsky 100
        fpu_init();
1882 jermar 101
        THREAD->fpu_context_exists = 1;
309 palkovsky 102
    }
906 palkovsky 103
#endif
52 vana 104
}
105
 
898 jermar 106
/** Take actions after THREAD had run.
897 jermar 107
 *
108
 * Perform actions that need to be
109
 * taken after the running thread
898 jermar 110
 * had been preempted by the scheduler.
897 jermar 111
 *
112
 * THREAD->lock is locked on entry
113
 *
114
 */
115
void after_thread_ran(void)
116
{
117
    after_thread_ran_arch();
118
}
119
 
458 decky 120
#ifdef CONFIG_FPU_LAZY
309 palkovsky 121
void scheduler_fpu_lazy_request(void)
122
{
907 palkovsky 123
restart:
309 palkovsky 124
    fpu_enable();
827 palkovsky 125
    spinlock_lock(&CPU->lock);
126
 
127
    /* Save old context */
309 palkovsky 128
    if (CPU->fpu_owner != NULL) {  
827 palkovsky 129
        spinlock_lock(&CPU->fpu_owner->lock);
906 palkovsky 130
        fpu_context_save(CPU->fpu_owner->saved_fpu_context);
309 palkovsky 131
        /* don't prevent migration */
1882 jermar 132
        CPU->fpu_owner->fpu_context_engaged = 0;
827 palkovsky 133
        spinlock_unlock(&CPU->fpu_owner->lock);
907 palkovsky 134
        CPU->fpu_owner = NULL;
309 palkovsky 135
    }
827 palkovsky 136
 
137
    spinlock_lock(&THREAD->lock);
898 jermar 138
    if (THREAD->fpu_context_exists) {
906 palkovsky 139
        fpu_context_restore(THREAD->saved_fpu_context);
898 jermar 140
    } else {
906 palkovsky 141
        /* Allocate FPU context */
142
        if (!THREAD->saved_fpu_context) {
143
            /* Might sleep */
144
            spinlock_unlock(&THREAD->lock);
907 palkovsky 145
            spinlock_unlock(&CPU->lock);
2067 jermar 146
            THREAD->saved_fpu_context =
2118 decky 147
                (fpu_context_t *) slab_alloc(fpu_context_slab, 0);
907 palkovsky 148
            /* We may have switched CPUs during slab_alloc */
149
            goto restart;
906 palkovsky 150
        }
151
        fpu_init();
1882 jermar 152
        THREAD->fpu_context_exists = 1;
309 palkovsky 153
    }
1882 jermar 154
    CPU->fpu_owner = THREAD;
309 palkovsky 155
    THREAD->fpu_context_engaged = 1;
898 jermar 156
    spinlock_unlock(&THREAD->lock);
827 palkovsky 157
 
158
    spinlock_unlock(&CPU->lock);
309 palkovsky 159
}
160
#endif
52 vana 161
 
107 decky 162
/** Initialize scheduler
163
 *
164
 * Initialize kernel scheduler.
165
 *
166
 */
1 jermar 167
void scheduler_init(void)
168
{
169
}
170
 
107 decky 171
/** Get thread to be scheduled
172
 *
173
 * Get the optimal thread to be scheduled
109 jermar 174
 * according to thread accounting and scheduler
107 decky 175
 * policy.
176
 *
177
 * @return Thread to be scheduled.
178
 *
179
 */
483 jermar 180
static thread_t *find_best_thread(void)
1 jermar 181
{
182
    thread_t *t;
183
    runq_t *r;
783 palkovsky 184
    int i;
1 jermar 185
 
227 jermar 186
    ASSERT(CPU != NULL);
187
 
1 jermar 188
loop:
413 jermar 189
    interrupts_enable();
1 jermar 190
 
783 palkovsky 191
    if (atomic_get(&CPU->nrdy) == 0) {
1 jermar 192
        /*
193
         * For there was nothing to run, the CPU goes to sleep
194
         * until a hardware interrupt or an IPI comes.
195
         * This improves energy saving and hyperthreading.
196
         */
785 jermar 197
 
198
        /*
199
         * An interrupt might occur right now and wake up a thread.
200
         * In such case, the CPU will continue to go to sleep
201
         * even though there is a runnable thread.
202
         */
203
 
1 jermar 204
         cpu_sleep();
205
         goto loop;
206
    }
207
 
413 jermar 208
    interrupts_disable();
114 jermar 209
 
2285 jermar 210
    for (i = 0; i < RQ_COUNT; i++) {
15 jermar 211
        r = &CPU->rq[i];
1 jermar 212
        spinlock_lock(&r->lock);
213
        if (r->n == 0) {
214
            /*
215
             * If this queue is empty, try a lower-priority queue.
216
             */
217
            spinlock_unlock(&r->lock);
218
            continue;
219
        }
213 jermar 220
 
783 palkovsky 221
        atomic_dec(&CPU->nrdy);
475 jermar 222
        atomic_dec(&nrdy);
1 jermar 223
        r->n--;
224
 
225
        /*
226
         * Take the first thread from the queue.
227
         */
228
        t = list_get_instance(r->rq_head.next, thread_t, rq_link);
229
        list_remove(&t->rq_link);
230
 
231
        spinlock_unlock(&r->lock);
232
 
233
        spinlock_lock(&t->lock);
15 jermar 234
        t->cpu = CPU;
1 jermar 235
 
2067 jermar 236
        t->ticks = us2ticks((i + 1) * 10000);
898 jermar 237
        t->priority = i;    /* correct rq index */
1 jermar 238
 
239
        /*
1854 jermar 240
         * Clear the THREAD_FLAG_STOLEN flag so that t can be migrated
241
         * when load balancing needs emerge.
1 jermar 242
         */
1854 jermar 243
        t->flags &= ~THREAD_FLAG_STOLEN;
1 jermar 244
        spinlock_unlock(&t->lock);
245
 
246
        return t;
247
    }
248
    goto loop;
249
 
250
}
251
 
107 decky 252
/** Prevent rq starvation
253
 *
254
 * Prevent low priority threads from starving in rq's.
255
 *
256
 * When the function decides to relink rq's, it reconnects
257
 * respective pointers so that in result threads with 'pri'
1708 jermar 258
 * greater or equal start are moved to a higher-priority queue.
107 decky 259
 *
260
 * @param start Threshold priority.
261
 *
1 jermar 262
 */
452 decky 263
static void relink_rq(int start)
1 jermar 264
{
265
    link_t head;
266
    runq_t *r;
267
    int i, n;
268
 
269
    list_initialize(&head);
15 jermar 270
    spinlock_lock(&CPU->lock);
271
    if (CPU->needs_relink > NEEDS_RELINK_MAX) {
2067 jermar 272
        for (i = start; i < RQ_COUNT - 1; i++) {
1 jermar 273
            /* remember and empty rq[i + 1] */
15 jermar 274
            r = &CPU->rq[i + 1];
1 jermar 275
            spinlock_lock(&r->lock);
276
            list_concat(&head, &r->rq_head);
277
            n = r->n;
278
            r->n = 0;
279
            spinlock_unlock(&r->lock);
280
 
281
            /* append rq[i + 1] to rq[i] */
15 jermar 282
            r = &CPU->rq[i];
1 jermar 283
            spinlock_lock(&r->lock);
284
            list_concat(&r->rq_head, &head);
285
            r->n += n;
286
            spinlock_unlock(&r->lock);
287
        }
15 jermar 288
        CPU->needs_relink = 0;
1 jermar 289
    }
784 palkovsky 290
    spinlock_unlock(&CPU->lock);
1 jermar 291
 
292
}
293
 
898 jermar 294
/** The scheduler
295
 *
296
 * The thread scheduling procedure.
297
 * Passes control directly to
298
 * scheduler_separated_stack().
299
 *
300
 */
301
void scheduler(void)
302
{
303
    volatile ipl_t ipl;
107 decky 304
 
898 jermar 305
    ASSERT(CPU != NULL);
306
 
307
    ipl = interrupts_disable();
308
 
309
    if (atomic_get(&haltstate))
310
        halt();
1007 decky 311
 
898 jermar 312
    if (THREAD) {
313
        spinlock_lock(&THREAD->lock);
2030 decky 314
 
315
        /* Update thread accounting */
316
        THREAD->cycles += get_cycle() - THREAD->last_cycle;
317
 
906 palkovsky 318
#ifndef CONFIG_FPU_LAZY
319
        fpu_context_save(THREAD->saved_fpu_context);
320
#endif
898 jermar 321
        if (!context_save(&THREAD->saved_context)) {
322
            /*
323
             * This is the place where threads leave scheduler();
324
             */
2030 decky 325
 
326
            /* Save current CPU cycle */
327
            THREAD->last_cycle = get_cycle();
328
 
898 jermar 329
            spinlock_unlock(&THREAD->lock);
330
            interrupts_restore(THREAD->saved_context.ipl);
1007 decky 331
 
898 jermar 332
            return;
333
        }
334
 
335
        /*
2067 jermar 336
         * Interrupt priority level of preempted thread is recorded
337
         * here to facilitate scheduler() invocations from
338
         * interrupts_disable()'d code (e.g. waitq_sleep_timeout()).
898 jermar 339
         */
340
        THREAD->saved_context.ipl = ipl;
341
    }
342
 
343
    /*
344
     * Through the 'THE' structure, we keep track of THREAD, TASK, CPU, VM
345
     * and preemption counter. At this point THE could be coming either
346
     * from THREAD's or CPU's stack.
347
     */
348
    the_copy(THE, (the_t *) CPU->stack);
349
 
350
    /*
351
     * We may not keep the old stack.
352
     * Reason: If we kept the old stack and got blocked, for instance, in
353
     * find_best_thread(), the old thread could get rescheduled by another
354
     * CPU and overwrite the part of its own stack that was also used by
355
     * the scheduler on this CPU.
356
     *
357
     * Moreover, we have to bypass the compiler-generated POP sequence
358
     * which is fooled by SP being set to the very top of the stack.
359
     * Therefore the scheduler() function continues in
360
     * scheduler_separated_stack().
361
     */
362
    context_save(&CPU->saved_context);
1854 jermar 363
    context_set(&CPU->saved_context, FADDR(scheduler_separated_stack),
2087 jermar 364
        (uintptr_t) CPU->stack, CPU_STACK_SIZE);
898 jermar 365
    context_restore(&CPU->saved_context);
366
    /* not reached */
367
}
368
 
107 decky 369
/** Scheduler stack switch wrapper
370
 *
371
 * Second part of the scheduler() function
372
 * using new stack. Handling the actual context
373
 * switch to a new thread.
374
 *
787 palkovsky 375
 * Assume THREAD->lock is held.
107 decky 376
 */
898 jermar 377
void scheduler_separated_stack(void)
1 jermar 378
{
379
    int priority;
2183 jermar 380
    DEADLOCK_PROBE_INIT(p_joinwq);
381
 
227 jermar 382
    ASSERT(CPU != NULL);
1007 decky 383
 
15 jermar 384
    if (THREAD) {
898 jermar 385
        /* must be run after the switch to scheduler stack */
897 jermar 386
        after_thread_ran();
387
 
15 jermar 388
        switch (THREAD->state) {
1888 jermar 389
        case Running:
125 jermar 390
            spinlock_unlock(&THREAD->lock);
391
            thread_ready(THREAD);
392
            break;
1 jermar 393
 
1888 jermar 394
        case Exiting:
1571 jermar 395
repeat:
2040 decky 396
            if (THREAD->detached) {
1571 jermar 397
                thread_destroy(THREAD);
398
            } else {
399
                /*
2067 jermar 400
                 * The thread structure is kept allocated until
401
                 * somebody calls thread_detach() on it.
1571 jermar 402
                 */
403
                if (!spinlock_trylock(&THREAD->join_wq.lock)) {
404
                    /*
405
                     * Avoid deadlock.
406
                     */
407
                    spinlock_unlock(&THREAD->lock);
2446 jermar 408
                    delay(HZ);
1571 jermar 409
                    spinlock_lock(&THREAD->lock);
2183 jermar 410
                    DEADLOCK_PROBE(p_joinwq,
411
                        DEADLOCK_THRESHOLD);
1571 jermar 412
                    goto repeat;
413
                }
2310 jermar 414
                _waitq_wakeup_unsafe(&THREAD->join_wq,
415
                    WAKEUP_FIRST);
1571 jermar 416
                spinlock_unlock(&THREAD->join_wq.lock);
417
 
2451 jermar 418
                THREAD->state = Lingering;
1571 jermar 419
                spinlock_unlock(&THREAD->lock);
420
            }
125 jermar 421
            break;
787 palkovsky 422
 
1888 jermar 423
        case Sleeping:
125 jermar 424
            /*
425
             * Prefer the thread after it's woken up.
426
             */
413 jermar 427
            THREAD->priority = -1;
1 jermar 428
 
125 jermar 429
            /*
2067 jermar 430
             * We need to release wq->lock which we locked in
431
             * waitq_sleep(). Address of wq->lock is kept in
432
             * THREAD->sleep_queue.
125 jermar 433
             */
434
            spinlock_unlock(&THREAD->sleep_queue->lock);
1 jermar 435
 
125 jermar 436
            /*
2067 jermar 437
             * Check for possible requests for out-of-context
438
             * invocation.
125 jermar 439
             */
440
            if (THREAD->call_me) {
441
                THREAD->call_me(THREAD->call_me_with);
442
                THREAD->call_me = NULL;
443
                THREAD->call_me_with = NULL;
444
            }
1 jermar 445
 
125 jermar 446
            spinlock_unlock(&THREAD->lock);
1 jermar 447
 
125 jermar 448
            break;
449
 
1888 jermar 450
        default:
125 jermar 451
            /*
452
             * Entering state is unexpected.
453
             */
2216 decky 454
            panic("tid%llu: unexpected state %s\n", THREAD->tid,
2285 jermar 455
                thread_states[THREAD->state]);
125 jermar 456
            break;
1 jermar 457
        }
897 jermar 458
 
15 jermar 459
        THREAD = NULL;
1 jermar 460
    }
198 jermar 461
 
15 jermar 462
    THREAD = find_best_thread();
1 jermar 463
 
15 jermar 464
    spinlock_lock(&THREAD->lock);
413 jermar 465
    priority = THREAD->priority;
15 jermar 466
    spinlock_unlock(&THREAD->lock);
192 jermar 467
 
1 jermar 468
    relink_rq(priority);       
469
 
470
    /*
2067 jermar 471
     * If both the old and the new task are the same, lots of work is
472
     * avoided.
1 jermar 473
     */
15 jermar 474
    if (TASK != THREAD->task) {
703 jermar 475
        as_t *as1 = NULL;
476
        as_t *as2;
1 jermar 477
 
15 jermar 478
        if (TASK) {
479
            spinlock_lock(&TASK->lock);
703 jermar 480
            as1 = TASK->as;
15 jermar 481
            spinlock_unlock(&TASK->lock);
1 jermar 482
        }
483
 
15 jermar 484
        spinlock_lock(&THREAD->task->lock);
703 jermar 485
        as2 = THREAD->task->as;
15 jermar 486
        spinlock_unlock(&THREAD->task->lock);
1 jermar 487
 
488
        /*
2067 jermar 489
         * Note that it is possible for two tasks to share one address
490
         * space.
1 jermar 491
         */
703 jermar 492
        if (as1 != as2) {
1 jermar 493
            /*
703 jermar 494
             * Both tasks and address spaces are different.
1 jermar 495
             * Replace the old one with the new one.
496
             */
823 jermar 497
            as_switch(as1, as2);
1 jermar 498
        }
906 palkovsky 499
        TASK = THREAD->task;
1187 jermar 500
        before_task_runs();
1 jermar 501
    }
502
 
1380 jermar 503
    spinlock_lock(&THREAD->lock);  
15 jermar 504
    THREAD->state = Running;
1 jermar 505
 
906 palkovsky 506
#ifdef SCHEDULER_VERBOSE
2216 decky 507
    printf("cpu%d: tid %llu (priority=%d, ticks=%llu, nrdy=%ld)\n",
2087 jermar 508
        CPU->id, THREAD->tid, THREAD->priority, THREAD->ticks,
509
        atomic_get(&CPU->nrdy));
906 palkovsky 510
#endif  
1 jermar 511
 
213 jermar 512
    /*
897 jermar 513
     * Some architectures provide late kernel PA2KA(identity)
514
     * mapping in a page fault handler. However, the page fault
515
     * handler uses the kernel stack of the running thread and
516
     * therefore cannot be used to map it. The kernel stack, if
517
     * necessary, is to be mapped in before_thread_runs(). This
518
     * function must be executed before the switch to the new stack.
519
     */
520
    before_thread_runs();
521
 
522
    /*
2067 jermar 523
     * Copy the knowledge of CPU, TASK, THREAD and preemption counter to
524
     * thread's stack.
213 jermar 525
     */
184 jermar 526
    the_copy(THE, (the_t *) THREAD->kstack);
527
 
15 jermar 528
    context_restore(&THREAD->saved_context);
1 jermar 529
    /* not reached */
530
}
531
 
458 decky 532
#ifdef CONFIG_SMP
107 decky 533
/** Load balancing thread
534
 *
535
 * SMP load balancing thread, supervising thread supplies
536
 * for the CPU it's wired to.
537
 *
538
 * @param arg Generic thread argument (unused).
539
 *
1 jermar 540
 */
541
void kcpulb(void *arg)
542
{
543
    thread_t *t;
2118 decky 544
    int count, average, j, k = 0;
545
    unsigned int i;
413 jermar 546
    ipl_t ipl;
1 jermar 547
 
1576 jermar 548
    /*
549
     * Detach kcpulb as nobody will call thread_join_timeout() on it.
550
     */
551
    thread_detach(THREAD);
552
 
1 jermar 553
loop:
554
    /*
779 jermar 555
     * Work in 1s intervals.
1 jermar 556
     */
779 jermar 557
    thread_sleep(1);
1 jermar 558
 
559
not_satisfied:
560
    /*
561
     * Calculate the number of threads that will be migrated/stolen from
562
     * other CPU's. Note that situation can have changed between two
563
     * passes. Each time get the most up to date counts.
564
     */
784 palkovsky 565
    average = atomic_get(&nrdy) / config.cpu_active + 1;
783 palkovsky 566
    count = average - atomic_get(&CPU->nrdy);
1 jermar 567
 
784 palkovsky 568
    if (count <= 0)
1 jermar 569
        goto satisfied;
570
 
571
    /*
2067 jermar 572
     * Searching least priority queues on all CPU's first and most priority
573
     * queues on all CPU's last.
1 jermar 574
     */
2285 jermar 575
    for (j = RQ_COUNT - 1; j >= 0; j--) {
2067 jermar 576
        for (i = 0; i < config.cpu_active; i++) {
1 jermar 577
            link_t *l;
578
            runq_t *r;
579
            cpu_t *cpu;
580
 
581
            cpu = &cpus[(i + k) % config.cpu_active];
582
 
583
            /*
584
             * Not interested in ourselves.
2067 jermar 585
             * Doesn't require interrupt disabling for kcpulb has
586
             * THREAD_FLAG_WIRED.
1 jermar 587
             */
15 jermar 588
            if (CPU == cpu)
783 palkovsky 589
                continue;
590
            if (atomic_get(&cpu->nrdy) <= average)
591
                continue;
1 jermar 592
 
784 palkovsky 593
            ipl = interrupts_disable();
115 jermar 594
            r = &cpu->rq[j];
1 jermar 595
            spinlock_lock(&r->lock);
596
            if (r->n == 0) {
597
                spinlock_unlock(&r->lock);
413 jermar 598
                interrupts_restore(ipl);
1 jermar 599
                continue;
600
            }
601
 
602
            t = NULL;
603
            l = r->rq_head.prev;    /* search rq from the back */
604
            while (l != &r->rq_head) {
605
                t = list_get_instance(l, thread_t, rq_link);
606
                /*
2067 jermar 607
                 * We don't want to steal CPU-wired threads
608
                 * neither threads already stolen. The latter
609
                 * prevents threads from migrating between CPU's
610
                 * without ever being run. We don't want to
611
                 * steal threads whose FPU context is still in
612
                 * CPU.
73 vana 613
                 */
1 jermar 614
                spinlock_lock(&t->lock);
2067 jermar 615
                if ((!(t->flags & (THREAD_FLAG_WIRED |
2285 jermar 616
                    THREAD_FLAG_STOLEN))) &&
617
                    (!(t->fpu_context_engaged))) {
1 jermar 618
                    /*
619
                     * Remove t from r.
620
                     */
621
                    spinlock_unlock(&t->lock);
622
 
783 palkovsky 623
                    atomic_dec(&cpu->nrdy);
475 jermar 624
                    atomic_dec(&nrdy);
1 jermar 625
 
125 jermar 626
                    r->n--;
1 jermar 627
                    list_remove(&t->rq_link);
628
 
629
                    break;
630
                }
631
                spinlock_unlock(&t->lock);
632
                l = l->prev;
633
                t = NULL;
634
            }
635
            spinlock_unlock(&r->lock);
636
 
637
            if (t) {
638
                /*
639
                 * Ready t on local CPU
640
                 */
641
                spinlock_lock(&t->lock);
906 palkovsky 642
#ifdef KCPULB_VERBOSE
2216 decky 643
                printf("kcpulb%d: TID %llu -> cpu%d, nrdy=%ld, "
2087 jermar 644
                    "avg=%nd\n", CPU->id, t->tid, CPU->id,
645
                    atomic_get(&CPU->nrdy),
646
                    atomic_get(&nrdy) / config.cpu_active);
906 palkovsky 647
#endif
1854 jermar 648
                t->flags |= THREAD_FLAG_STOLEN;
1115 jermar 649
                t->state = Entering;
1 jermar 650
                spinlock_unlock(&t->lock);
651
 
652
                thread_ready(t);
653
 
413 jermar 654
                interrupts_restore(ipl);
1 jermar 655
 
656
                if (--count == 0)
657
                    goto satisfied;
658
 
659
                /*
2067 jermar 660
                 * We are not satisfied yet, focus on another
661
                 * CPU next time.
1 jermar 662
                 */
663
                k++;
664
 
665
                continue;
666
            }
413 jermar 667
            interrupts_restore(ipl);
1 jermar 668
        }
669
    }
670
 
783 palkovsky 671
    if (atomic_get(&CPU->nrdy)) {
1 jermar 672
        /*
673
         * Be a little bit light-weight and let migrated threads run.
674
         */
675
        scheduler();
779 jermar 676
    } else {
1 jermar 677
        /*
678
         * We failed to migrate a single thread.
779 jermar 679
         * Give up this turn.
1 jermar 680
         */
779 jermar 681
        goto loop;
1 jermar 682
    }
683
 
684
    goto not_satisfied;
125 jermar 685
 
1 jermar 686
satisfied:
687
    goto loop;
688
}
689
 
458 decky 690
#endif /* CONFIG_SMP */
775 palkovsky 691
 
692
 
693
/** Print information about threads & scheduler queues */
694
void sched_print_list(void)
695
{
696
    ipl_t ipl;
2118 decky 697
    unsigned int cpu, i;
775 palkovsky 698
    runq_t *r;
699
    thread_t *t;
700
    link_t *cur;
701
 
702
    /* We are going to mess with scheduler structures,
703
     * let's not be interrupted */
704
    ipl = interrupts_disable();
2118 decky 705
    for (cpu = 0; cpu < config.cpu_count; cpu++) {
898 jermar 706
 
775 palkovsky 707
        if (!cpus[cpu].active)
708
            continue;
898 jermar 709
 
775 palkovsky 710
        spinlock_lock(&cpus[cpu].lock);
1221 decky 711
        printf("cpu%d: address=%p, nrdy=%ld, needs_relink=%ld\n",
2087 jermar 712
            cpus[cpu].id, &cpus[cpu], atomic_get(&cpus[cpu].nrdy),
713
            cpus[cpu].needs_relink);
775 palkovsky 714
 
2067 jermar 715
        for (i = 0; i < RQ_COUNT; i++) {
775 palkovsky 716
            r = &cpus[cpu].rq[i];
717
            spinlock_lock(&r->lock);
718
            if (!r->n) {
719
                spinlock_unlock(&r->lock);
720
                continue;
721
            }
898 jermar 722
            printf("\trq[%d]: ", i);
2067 jermar 723
            for (cur = r->rq_head.next; cur != &r->rq_head;
724
                cur = cur->next) {
775 palkovsky 725
                t = list_get_instance(cur, thread_t, rq_link);
2216 decky 726
                printf("%llu(%s) ", t->tid,
2087 jermar 727
                    thread_states[t->state]);
775 palkovsky 728
            }
729
            printf("\n");
730
            spinlock_unlock(&r->lock);
731
        }
732
        spinlock_unlock(&cpus[cpu].lock);
733
    }
734
 
735
    interrupts_restore(ipl);
736
}
1702 cejka 737
 
1757 jermar 738
/** @}
1702 cejka 739
 */