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1/*
2 * Copyright 2015 Advanced Micro Devices, Inc.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 */
23
24/**
25 * DOC: Overview
26 *
27 * The GPU scheduler provides entities which allow userspace to push jobs
28 * into software queues which are then scheduled on a hardware run queue.
29 * The software queues have a priority among them. The scheduler selects the entities
30 * from the run queue using a FIFO. The scheduler provides dependency handling
31 * features among jobs. The driver is supposed to provide callback functions for
32 * backend operations to the scheduler like submitting a job to hardware run queue,
33 * returning the dependencies of a job etc.
34 *
35 * The organisation of the scheduler is the following:
36 *
37 * 1. Each hw run queue has one scheduler
38 * 2. Each scheduler has multiple run queues with different priorities
39 * (e.g., HIGH_HW,HIGH_SW, KERNEL, NORMAL)
40 * 3. Each scheduler run queue has a queue of entities to schedule
41 * 4. Entities themselves maintain a queue of jobs that will be scheduled on
42 * the hardware.
43 *
44 * The jobs in a entity are always scheduled in the order that they were pushed.
45 */
46
47#include <linux/kthread.h>
48#include <linux/wait.h>
49#include <linux/sched.h>
50#include <uapi/linux/sched/types.h>
51
52#include <drm/drm_print.h>
53#include <drm/gpu_scheduler.h>
54#include <drm/spsc_queue.h>
55
56#define CREATE_TRACE_POINTS
57#include "gpu_scheduler_trace.h"
58
59#define to_drm_sched_job(sched_job) \
60 container_of((sched_job), struct drm_sched_job, queue_node)
61
62static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb);
63
64/**
65 * drm_sched_rq_init - initialize a given run queue struct
66 *
67 * @rq: scheduler run queue
68 *
69 * Initializes a scheduler runqueue.
70 */
71static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
72 struct drm_sched_rq *rq)
73{
74 spin_lock_init(&rq->lock);
75 INIT_LIST_HEAD(&rq->entities);
76 rq->current_entity = NULL;
77 rq->sched = sched;
78}
79
80/**
81 * drm_sched_rq_add_entity - add an entity
82 *
83 * @rq: scheduler run queue
84 * @entity: scheduler entity
85 *
86 * Adds a scheduler entity to the run queue.
87 */
88void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
89 struct drm_sched_entity *entity)
90{
91 if (!list_empty(&entity->list))
92 return;
93 spin_lock(&rq->lock);
94 list_add_tail(&entity->list, &rq->entities);
95 spin_unlock(&rq->lock);
96}
97
98/**
99 * drm_sched_rq_remove_entity - remove an entity
100 *
101 * @rq: scheduler run queue
102 * @entity: scheduler entity
103 *
104 * Removes a scheduler entity from the run queue.
105 */
106void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
107 struct drm_sched_entity *entity)
108{
109 if (list_empty(&entity->list))
110 return;
111 spin_lock(&rq->lock);
112 list_del_init(&entity->list);
113 if (rq->current_entity == entity)
114 rq->current_entity = NULL;
115 spin_unlock(&rq->lock);
116}
117
118/**
119 * drm_sched_rq_select_entity - Select an entity which could provide a job to run
120 *
121 * @rq: scheduler run queue to check.
122 *
123 * Try to find a ready entity, returns NULL if none found.
124 */
125static struct drm_sched_entity *
126drm_sched_rq_select_entity(struct drm_sched_rq *rq)
127{
128 struct drm_sched_entity *entity;
129
130 spin_lock(&rq->lock);
131
132 entity = rq->current_entity;
133 if (entity) {
134 list_for_each_entry_continue(entity, &rq->entities, list) {
135 if (drm_sched_entity_is_ready(entity)) {
136 rq->current_entity = entity;
137 spin_unlock(&rq->lock);
138 return entity;
139 }
140 }
141 }
142
143 list_for_each_entry(entity, &rq->entities, list) {
144
145 if (drm_sched_entity_is_ready(entity)) {
146 rq->current_entity = entity;
147 spin_unlock(&rq->lock);
148 return entity;
149 }
150
151 if (entity == rq->current_entity)
152 break;
153 }
154
155 spin_unlock(&rq->lock);
156
157 return NULL;
158}
159
160/**
161 * drm_sched_dependency_optimized
162 *
163 * @fence: the dependency fence
164 * @entity: the entity which depends on the above fence
165 *
166 * Returns true if the dependency can be optimized and false otherwise
167 */
168bool drm_sched_dependency_optimized(struct dma_fence* fence,
169 struct drm_sched_entity *entity)
170{
171 struct drm_gpu_scheduler *sched = entity->rq->sched;
172 struct drm_sched_fence *s_fence;
173
174 if (!fence || dma_fence_is_signaled(fence))
175 return false;
176 if (fence->context == entity->fence_context)
177 return true;
178 s_fence = to_drm_sched_fence(fence);
179 if (s_fence && s_fence->sched == sched)
180 return true;
181
182 return false;
183}
184EXPORT_SYMBOL(drm_sched_dependency_optimized);
185
186/**
187 * drm_sched_start_timeout - start timeout for reset worker
188 *
189 * @sched: scheduler instance to start the worker for
190 *
191 * Start the timeout for the given scheduler.
192 */
193static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched)
194{
195 if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
196 !list_empty(&sched->ring_mirror_list))
197 schedule_delayed_work(&sched->work_tdr, sched->timeout);
198}
199
200/**
201 * drm_sched_fault - immediately start timeout handler
202 *
203 * @sched: scheduler where the timeout handling should be started.
204 *
205 * Start timeout handling immediately when the driver detects a hardware fault.
206 */
207void drm_sched_fault(struct drm_gpu_scheduler *sched)
208{
209 mod_delayed_work(system_wq, &sched->work_tdr, 0);
210}
211EXPORT_SYMBOL(drm_sched_fault);
212
213/**
214 * drm_sched_suspend_timeout - Suspend scheduler job timeout
215 *
216 * @sched: scheduler instance for which to suspend the timeout
217 *
218 * Suspend the delayed work timeout for the scheduler. This is done by
219 * modifying the delayed work timeout to an arbitrary large value,
220 * MAX_SCHEDULE_TIMEOUT in this case. Note that this function can be
221 * called from an IRQ context.
222 *
223 * Returns the timeout remaining
224 *
225 */
226unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched)
227{
228 unsigned long sched_timeout, now = jiffies;
229
230 sched_timeout = sched->work_tdr.timer.expires;
231
232 /*
233 * Modify the timeout to an arbitrarily large value. This also prevents
234 * the timeout to be restarted when new submissions arrive
235 */
236 if (mod_delayed_work(system_wq, &sched->work_tdr, MAX_SCHEDULE_TIMEOUT)
237 && time_after(sched_timeout, now))
238 return sched_timeout - now;
239 else
240 return sched->timeout;
241}
242EXPORT_SYMBOL(drm_sched_suspend_timeout);
243
244/**
245 * drm_sched_resume_timeout - Resume scheduler job timeout
246 *
247 * @sched: scheduler instance for which to resume the timeout
248 * @remaining: remaining timeout
249 *
250 * Resume the delayed work timeout for the scheduler. Note that
251 * this function can be called from an IRQ context.
252 */
253void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
254 unsigned long remaining)
255{
256 unsigned long flags;
257
258 spin_lock_irqsave(&sched->job_list_lock, flags);
259
260 if (list_empty(&sched->ring_mirror_list))
261 cancel_delayed_work(&sched->work_tdr);
262 else
263 mod_delayed_work(system_wq, &sched->work_tdr, remaining);
264
265 spin_unlock_irqrestore(&sched->job_list_lock, flags);
266}
267EXPORT_SYMBOL(drm_sched_resume_timeout);
268
269static void drm_sched_job_begin(struct drm_sched_job *s_job)
270{
271 struct drm_gpu_scheduler *sched = s_job->sched;
272 unsigned long flags;
273
274 spin_lock_irqsave(&sched->job_list_lock, flags);
275 list_add_tail(&s_job->node, &sched->ring_mirror_list);
276 drm_sched_start_timeout(sched);
277 spin_unlock_irqrestore(&sched->job_list_lock, flags);
278}
279
280static void drm_sched_job_timedout(struct work_struct *work)
281{
282 struct drm_gpu_scheduler *sched;
283 struct drm_sched_job *job;
284 unsigned long flags;
285
286 sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
287 job = list_first_entry_or_null(&sched->ring_mirror_list,
288 struct drm_sched_job, node);
289
290 if (job) {
291 job->sched->ops->timedout_job(job);
292
293 /*
294 * Guilty job did complete and hence needs to be manually removed
295 * See drm_sched_stop doc.
296 */
297 if (sched->free_guilty) {
298 job->sched->ops->free_job(job);
299 sched->free_guilty = false;
300 }
301 }
302
303 spin_lock_irqsave(&sched->job_list_lock, flags);
304 drm_sched_start_timeout(sched);
305 spin_unlock_irqrestore(&sched->job_list_lock, flags);
306}
307
308 /**
309 * drm_sched_increase_karma - Update sched_entity guilty flag
310 *
311 * @bad: The job guilty of time out
312 *
313 * Increment on every hang caused by the 'bad' job. If this exceeds the hang
314 * limit of the scheduler then the respective sched entity is marked guilty and
315 * jobs from it will not be scheduled further
316 */
317void drm_sched_increase_karma(struct drm_sched_job *bad)
318{
319 int i;
320 struct drm_sched_entity *tmp;
321 struct drm_sched_entity *entity;
322 struct drm_gpu_scheduler *sched = bad->sched;
323
324 /* don't increase @bad's karma if it's from KERNEL RQ,
325 * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
326 * corrupt but keep in mind that kernel jobs always considered good.
327 */
328 if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
329 atomic_inc(&bad->karma);
330 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
331 i++) {
332 struct drm_sched_rq *rq = &sched->sched_rq[i];
333
334 spin_lock(&rq->lock);
335 list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
336 if (bad->s_fence->scheduled.context ==
337 entity->fence_context) {
338 if (atomic_read(&bad->karma) >
339 bad->sched->hang_limit)
340 if (entity->guilty)
341 atomic_set(entity->guilty, 1);
342 break;
343 }
344 }
345 spin_unlock(&rq->lock);
346 if (&entity->list != &rq->entities)
347 break;
348 }
349 }
350}
351EXPORT_SYMBOL(drm_sched_increase_karma);
352
353/**
354 * drm_sched_stop - stop the scheduler
355 *
356 * @sched: scheduler instance
357 * @bad: job which caused the time out
358 *
359 * Stop the scheduler and also removes and frees all completed jobs.
360 * Note: bad job will not be freed as it might be used later and so it's
361 * callers responsibility to release it manually if it's not part of the
362 * mirror list any more.
363 *
364 */
365void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
366{
367 struct drm_sched_job *s_job, *tmp;
368 unsigned long flags;
369
370 kthread_park(sched->thread);
371
372 /*
373 * Iterate the job list from later to earlier one and either deactive
374 * their HW callbacks or remove them from mirror list if they already
375 * signaled.
376 * This iteration is thread safe as sched thread is stopped.
377 */
378 list_for_each_entry_safe_reverse(s_job, tmp, &sched->ring_mirror_list, node) {
379 if (s_job->s_fence->parent &&
380 dma_fence_remove_callback(s_job->s_fence->parent,
381 &s_job->cb)) {
382 atomic_dec(&sched->hw_rq_count);
383 } else {
384 /*
385 * remove job from ring_mirror_list.
386 * Locking here is for concurrent resume timeout
387 */
388 spin_lock_irqsave(&sched->job_list_lock, flags);
389 list_del_init(&s_job->node);
390 spin_unlock_irqrestore(&sched->job_list_lock, flags);
391
392 /*
393 * Wait for job's HW fence callback to finish using s_job
394 * before releasing it.
395 *
396 * Job is still alive so fence refcount at least 1
397 */
398 dma_fence_wait(&s_job->s_fence->finished, false);
399
400 /*
401 * We must keep bad job alive for later use during
402 * recovery by some of the drivers but leave a hint
403 * that the guilty job must be released.
404 */
405 if (bad != s_job)
406 sched->ops->free_job(s_job);
407 else
408 sched->free_guilty = true;
409 }
410 }
411
412 /*
413 * Stop pending timer in flight as we rearm it in drm_sched_start. This
414 * avoids the pending timeout work in progress to fire right away after
415 * this TDR finished and before the newly restarted jobs had a
416 * chance to complete.
417 */
418 cancel_delayed_work(&sched->work_tdr);
419}
420
421EXPORT_SYMBOL(drm_sched_stop);
422
423/**
424 * drm_sched_job_recovery - recover jobs after a reset
425 *
426 * @sched: scheduler instance
427 * @full_recovery: proceed with complete sched restart
428 *
429 */
430void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
431{
432 struct drm_sched_job *s_job, *tmp;
433 unsigned long flags;
434 int r;
435
436 /*
437 * Locking the list is not required here as the sched thread is parked
438 * so no new jobs are being inserted or removed. Also concurrent
439 * GPU recovers can't run in parallel.
440 */
441 list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
442 struct dma_fence *fence = s_job->s_fence->parent;
443
444 atomic_inc(&sched->hw_rq_count);
445
446 if (!full_recovery)
447 continue;
448
449 if (fence) {
450 r = dma_fence_add_callback(fence, &s_job->cb,
451 drm_sched_process_job);
452 if (r == -ENOENT)
453 drm_sched_process_job(fence, &s_job->cb);
454 else if (r)
455 DRM_ERROR("fence add callback failed (%d)\n",
456 r);
457 } else
458 drm_sched_process_job(NULL, &s_job->cb);
459 }
460
461 if (full_recovery) {
462 spin_lock_irqsave(&sched->job_list_lock, flags);
463 drm_sched_start_timeout(sched);
464 spin_unlock_irqrestore(&sched->job_list_lock, flags);
465 }
466
467 kthread_unpark(sched->thread);
468}
469EXPORT_SYMBOL(drm_sched_start);
470
471/**
472 * drm_sched_resubmit_jobs - helper to relunch job from mirror ring list
473 *
474 * @sched: scheduler instance
475 *
476 */
477void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
478{
479 struct drm_sched_job *s_job, *tmp;
480 uint64_t guilty_context;
481 bool found_guilty = false;
482 struct dma_fence *fence;
483
484 list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
485 struct drm_sched_fence *s_fence = s_job->s_fence;
486
487 if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
488 found_guilty = true;
489 guilty_context = s_job->s_fence->scheduled.context;
490 }
491
492 if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
493 dma_fence_set_error(&s_fence->finished, -ECANCELED);
494
495 dma_fence_put(s_job->s_fence->parent);
496 fence = sched->ops->run_job(s_job);
497
498 if (IS_ERR_OR_NULL(fence)) {
499 s_job->s_fence->parent = NULL;
500 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
501 } else {
502 s_job->s_fence->parent = fence;
503 }
504
505
506 }
507}
508EXPORT_SYMBOL(drm_sched_resubmit_jobs);
509
510/**
511 * drm_sched_job_init - init a scheduler job
512 *
513 * @job: scheduler job to init
514 * @entity: scheduler entity to use
515 * @owner: job owner for debugging
516 *
517 * Refer to drm_sched_entity_push_job() documentation
518 * for locking considerations.
519 *
520 * Returns 0 for success, negative error code otherwise.
521 */
522int drm_sched_job_init(struct drm_sched_job *job,
523 struct drm_sched_entity *entity,
524 void *owner)
525{
526 struct drm_gpu_scheduler *sched;
527
528 drm_sched_entity_select_rq(entity);
529 if (!entity->rq)
530 return -ENOENT;
531
532 sched = entity->rq->sched;
533
534 job->sched = sched;
535 job->entity = entity;
536 job->s_priority = entity->rq - sched->sched_rq;
537 job->s_fence = drm_sched_fence_create(entity, owner);
538 if (!job->s_fence)
539 return -ENOMEM;
540 job->id = atomic64_inc_return(&sched->job_id_count);
541
542 INIT_LIST_HEAD(&job->node);
543
544 return 0;
545}
546EXPORT_SYMBOL(drm_sched_job_init);
547
548/**
549 * drm_sched_job_cleanup - clean up scheduler job resources
550 *
551 * @job: scheduler job to clean up
552 */
553void drm_sched_job_cleanup(struct drm_sched_job *job)
554{
555 dma_fence_put(&job->s_fence->finished);
556 job->s_fence = NULL;
557}
558EXPORT_SYMBOL(drm_sched_job_cleanup);
559
560/**
561 * drm_sched_ready - is the scheduler ready
562 *
563 * @sched: scheduler instance
564 *
565 * Return true if we can push more jobs to the hw, otherwise false.
566 */
567static bool drm_sched_ready(struct drm_gpu_scheduler *sched)
568{
569 return atomic_read(&sched->hw_rq_count) <
570 sched->hw_submission_limit;
571}
572
573/**
574 * drm_sched_wakeup - Wake up the scheduler when it is ready
575 *
576 * @sched: scheduler instance
577 *
578 */
579void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
580{
581 if (drm_sched_ready(sched))
582 wake_up_interruptible(&sched->wake_up_worker);
583}
584
585/**
586 * drm_sched_select_entity - Select next entity to process
587 *
588 * @sched: scheduler instance
589 *
590 * Returns the entity to process or NULL if none are found.
591 */
592static struct drm_sched_entity *
593drm_sched_select_entity(struct drm_gpu_scheduler *sched)
594{
595 struct drm_sched_entity *entity;
596 int i;
597
598 if (!drm_sched_ready(sched))
599 return NULL;
600
601 /* Kernel run queue has higher priority than normal run queue*/
602 for (i = DRM_SCHED_PRIORITY_MAX - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
603 entity = drm_sched_rq_select_entity(&sched->sched_rq[i]);
604 if (entity)
605 break;
606 }
607
608 return entity;
609}
610
611/**
612 * drm_sched_process_job - process a job
613 *
614 * @f: fence
615 * @cb: fence callbacks
616 *
617 * Called after job has finished execution.
618 */
619static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb)
620{
621 struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
622 struct drm_sched_fence *s_fence = s_job->s_fence;
623 struct drm_gpu_scheduler *sched = s_fence->sched;
624
625 atomic_dec(&sched->hw_rq_count);
626 atomic_dec(&sched->num_jobs);
627
628 trace_drm_sched_process_job(s_fence);
629
630 drm_sched_fence_finished(s_fence);
631 wake_up_interruptible(&sched->wake_up_worker);
632}
633
634/**
635 * drm_sched_cleanup_jobs - destroy finished jobs
636 *
637 * @sched: scheduler instance
638 *
639 * Remove all finished jobs from the mirror list and destroy them.
640 */
641static void drm_sched_cleanup_jobs(struct drm_gpu_scheduler *sched)
642{
643 unsigned long flags;
644
645 /* Don't destroy jobs while the timeout worker is running */
646 if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
647 !cancel_delayed_work(&sched->work_tdr))
648 return;
649
650
651 while (!list_empty(&sched->ring_mirror_list)) {
652 struct drm_sched_job *job;
653
654 job = list_first_entry(&sched->ring_mirror_list,
655 struct drm_sched_job, node);
656 if (!dma_fence_is_signaled(&job->s_fence->finished))
657 break;
658
659 spin_lock_irqsave(&sched->job_list_lock, flags);
660 /* remove job from ring_mirror_list */
661 list_del_init(&job->node);
662 spin_unlock_irqrestore(&sched->job_list_lock, flags);
663
664 sched->ops->free_job(job);
665 }
666
667 /* queue timeout for next job */
668 spin_lock_irqsave(&sched->job_list_lock, flags);
669 drm_sched_start_timeout(sched);
670 spin_unlock_irqrestore(&sched->job_list_lock, flags);
671
672}
673
674/**
675 * drm_sched_blocked - check if the scheduler is blocked
676 *
677 * @sched: scheduler instance
678 *
679 * Returns true if blocked, otherwise false.
680 */
681static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
682{
683 if (kthread_should_park()) {
684 kthread_parkme();
685 return true;
686 }
687
688 return false;
689}
690
691/**
692 * drm_sched_main - main scheduler thread
693 *
694 * @param: scheduler instance
695 *
696 * Returns 0.
697 */
698static int drm_sched_main(void *param)
699{
700 struct sched_param sparam = {.sched_priority = 1};
701 struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
702 int r;
703
704 sched_setscheduler(current, SCHED_FIFO, &sparam);
705
706 while (!kthread_should_stop()) {
707 struct drm_sched_entity *entity = NULL;
708 struct drm_sched_fence *s_fence;
709 struct drm_sched_job *sched_job;
710 struct dma_fence *fence;
711
712 wait_event_interruptible(sched->wake_up_worker,
713 (drm_sched_cleanup_jobs(sched),
714 (!drm_sched_blocked(sched) &&
715 (entity = drm_sched_select_entity(sched))) ||
716 kthread_should_stop()));
717
718 if (!entity)
719 continue;
720
721 sched_job = drm_sched_entity_pop_job(entity);
722 if (!sched_job)
723 continue;
724
725 s_fence = sched_job->s_fence;
726
727 atomic_inc(&sched->hw_rq_count);
728 drm_sched_job_begin(sched_job);
729
730 fence = sched->ops->run_job(sched_job);
731 drm_sched_fence_scheduled(s_fence);
732
733 if (!IS_ERR_OR_NULL(fence)) {
734 s_fence->parent = dma_fence_get(fence);
735 r = dma_fence_add_callback(fence, &sched_job->cb,
736 drm_sched_process_job);
737 if (r == -ENOENT)
738 drm_sched_process_job(fence, &sched_job->cb);
739 else if (r)
740 DRM_ERROR("fence add callback failed (%d)\n",
741 r);
742 dma_fence_put(fence);
743 } else {
744
745 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
746 drm_sched_process_job(NULL, &sched_job->cb);
747 }
748
749 wake_up(&sched->job_scheduled);
750 }
751 return 0;
752}
753
754/**
755 * drm_sched_init - Init a gpu scheduler instance
756 *
757 * @sched: scheduler instance
758 * @ops: backend operations for this scheduler
759 * @hw_submission: number of hw submissions that can be in flight
760 * @hang_limit: number of times to allow a job to hang before dropping it
761 * @timeout: timeout value in jiffies for the scheduler
762 * @name: name used for debugging
763 *
764 * Return 0 on success, otherwise error code.
765 */
766int drm_sched_init(struct drm_gpu_scheduler *sched,
767 const struct drm_sched_backend_ops *ops,
768 unsigned hw_submission,
769 unsigned hang_limit,
770 long timeout,
771 const char *name)
772{
773 int i, ret;
774 sched->ops = ops;
775 sched->hw_submission_limit = hw_submission;
776 sched->name = name;
777 sched->timeout = timeout;
778 sched->hang_limit = hang_limit;
779 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_MAX; i++)
780 drm_sched_rq_init(sched, &sched->sched_rq[i]);
781
782 init_waitqueue_head(&sched->wake_up_worker);
783 init_waitqueue_head(&sched->job_scheduled);
784 INIT_LIST_HEAD(&sched->ring_mirror_list);
785 spin_lock_init(&sched->job_list_lock);
786 atomic_set(&sched->hw_rq_count, 0);
787 INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
788 atomic_set(&sched->num_jobs, 0);
789 atomic64_set(&sched->job_id_count, 0);
790
791 /* Each scheduler will run on a seperate kernel thread */
792 sched->thread = kthread_run(drm_sched_main, sched, sched->name);
793 if (IS_ERR(sched->thread)) {
794 ret = PTR_ERR(sched->thread);
795 sched->thread = NULL;
796 DRM_ERROR("Failed to create scheduler for %s.\n", name);
797 return ret;
798 }
799
800 sched->ready = true;
801 return 0;
802}
803EXPORT_SYMBOL(drm_sched_init);
804
805/**
806 * drm_sched_fini - Destroy a gpu scheduler
807 *
808 * @sched: scheduler instance
809 *
810 * Tears down and cleans up the scheduler.
811 */
812void drm_sched_fini(struct drm_gpu_scheduler *sched)
813{
814 if (sched->thread)
815 kthread_stop(sched->thread);
816
817 sched->ready = false;
818}
819EXPORT_SYMBOL(drm_sched_fini);
1/*
2 * Copyright 2015 Advanced Micro Devices, Inc.
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
13 *
14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
17 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
18 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
19 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
20 * OTHER DEALINGS IN THE SOFTWARE.
21 *
22 */
23
24/**
25 * DOC: Overview
26 *
27 * The GPU scheduler provides entities which allow userspace to push jobs
28 * into software queues which are then scheduled on a hardware run queue.
29 * The software queues have a priority among them. The scheduler selects the entities
30 * from the run queue using a FIFO. The scheduler provides dependency handling
31 * features among jobs. The driver is supposed to provide callback functions for
32 * backend operations to the scheduler like submitting a job to hardware run queue,
33 * returning the dependencies of a job etc.
34 *
35 * The organisation of the scheduler is the following:
36 *
37 * 1. Each hw run queue has one scheduler
38 * 2. Each scheduler has multiple run queues with different priorities
39 * (e.g., HIGH_HW,HIGH_SW, KERNEL, NORMAL)
40 * 3. Each scheduler run queue has a queue of entities to schedule
41 * 4. Entities themselves maintain a queue of jobs that will be scheduled on
42 * the hardware.
43 *
44 * The jobs in a entity are always scheduled in the order that they were pushed.
45 */
46
47#include <linux/kthread.h>
48#include <linux/wait.h>
49#include <linux/sched.h>
50#include <linux/completion.h>
51#include <uapi/linux/sched/types.h>
52
53#include <drm/drm_print.h>
54#include <drm/gpu_scheduler.h>
55#include <drm/spsc_queue.h>
56
57#define CREATE_TRACE_POINTS
58#include "gpu_scheduler_trace.h"
59
60#define to_drm_sched_job(sched_job) \
61 container_of((sched_job), struct drm_sched_job, queue_node)
62
63/**
64 * drm_sched_rq_init - initialize a given run queue struct
65 *
66 * @sched: scheduler instance to associate with this run queue
67 * @rq: scheduler run queue
68 *
69 * Initializes a scheduler runqueue.
70 */
71static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
72 struct drm_sched_rq *rq)
73{
74 spin_lock_init(&rq->lock);
75 INIT_LIST_HEAD(&rq->entities);
76 rq->current_entity = NULL;
77 rq->sched = sched;
78}
79
80/**
81 * drm_sched_rq_add_entity - add an entity
82 *
83 * @rq: scheduler run queue
84 * @entity: scheduler entity
85 *
86 * Adds a scheduler entity to the run queue.
87 */
88void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
89 struct drm_sched_entity *entity)
90{
91 if (!list_empty(&entity->list))
92 return;
93 spin_lock(&rq->lock);
94 atomic_inc(rq->sched->score);
95 list_add_tail(&entity->list, &rq->entities);
96 spin_unlock(&rq->lock);
97}
98
99/**
100 * drm_sched_rq_remove_entity - remove an entity
101 *
102 * @rq: scheduler run queue
103 * @entity: scheduler entity
104 *
105 * Removes a scheduler entity from the run queue.
106 */
107void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
108 struct drm_sched_entity *entity)
109{
110 if (list_empty(&entity->list))
111 return;
112 spin_lock(&rq->lock);
113 atomic_dec(rq->sched->score);
114 list_del_init(&entity->list);
115 if (rq->current_entity == entity)
116 rq->current_entity = NULL;
117 spin_unlock(&rq->lock);
118}
119
120/**
121 * drm_sched_rq_select_entity - Select an entity which could provide a job to run
122 *
123 * @rq: scheduler run queue to check.
124 *
125 * Try to find a ready entity, returns NULL if none found.
126 */
127static struct drm_sched_entity *
128drm_sched_rq_select_entity(struct drm_sched_rq *rq)
129{
130 struct drm_sched_entity *entity;
131
132 spin_lock(&rq->lock);
133
134 entity = rq->current_entity;
135 if (entity) {
136 list_for_each_entry_continue(entity, &rq->entities, list) {
137 if (drm_sched_entity_is_ready(entity)) {
138 rq->current_entity = entity;
139 reinit_completion(&entity->entity_idle);
140 spin_unlock(&rq->lock);
141 return entity;
142 }
143 }
144 }
145
146 list_for_each_entry(entity, &rq->entities, list) {
147
148 if (drm_sched_entity_is_ready(entity)) {
149 rq->current_entity = entity;
150 reinit_completion(&entity->entity_idle);
151 spin_unlock(&rq->lock);
152 return entity;
153 }
154
155 if (entity == rq->current_entity)
156 break;
157 }
158
159 spin_unlock(&rq->lock);
160
161 return NULL;
162}
163
164/**
165 * drm_sched_job_done - complete a job
166 * @s_job: pointer to the job which is done
167 *
168 * Finish the job's fence and wake up the worker thread.
169 */
170static void drm_sched_job_done(struct drm_sched_job *s_job)
171{
172 struct drm_sched_fence *s_fence = s_job->s_fence;
173 struct drm_gpu_scheduler *sched = s_fence->sched;
174
175 atomic_dec(&sched->hw_rq_count);
176 atomic_dec(sched->score);
177
178 trace_drm_sched_process_job(s_fence);
179
180 dma_fence_get(&s_fence->finished);
181 drm_sched_fence_finished(s_fence);
182 dma_fence_put(&s_fence->finished);
183 wake_up_interruptible(&sched->wake_up_worker);
184}
185
186/**
187 * drm_sched_job_done_cb - the callback for a done job
188 * @f: fence
189 * @cb: fence callbacks
190 */
191static void drm_sched_job_done_cb(struct dma_fence *f, struct dma_fence_cb *cb)
192{
193 struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
194
195 drm_sched_job_done(s_job);
196}
197
198/**
199 * drm_sched_dependency_optimized
200 *
201 * @fence: the dependency fence
202 * @entity: the entity which depends on the above fence
203 *
204 * Returns true if the dependency can be optimized and false otherwise
205 */
206bool drm_sched_dependency_optimized(struct dma_fence* fence,
207 struct drm_sched_entity *entity)
208{
209 struct drm_gpu_scheduler *sched = entity->rq->sched;
210 struct drm_sched_fence *s_fence;
211
212 if (!fence || dma_fence_is_signaled(fence))
213 return false;
214 if (fence->context == entity->fence_context)
215 return true;
216 s_fence = to_drm_sched_fence(fence);
217 if (s_fence && s_fence->sched == sched)
218 return true;
219
220 return false;
221}
222EXPORT_SYMBOL(drm_sched_dependency_optimized);
223
224/**
225 * drm_sched_start_timeout - start timeout for reset worker
226 *
227 * @sched: scheduler instance to start the worker for
228 *
229 * Start the timeout for the given scheduler.
230 */
231static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched)
232{
233 if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
234 !list_empty(&sched->pending_list))
235 schedule_delayed_work(&sched->work_tdr, sched->timeout);
236}
237
238/**
239 * drm_sched_fault - immediately start timeout handler
240 *
241 * @sched: scheduler where the timeout handling should be started.
242 *
243 * Start timeout handling immediately when the driver detects a hardware fault.
244 */
245void drm_sched_fault(struct drm_gpu_scheduler *sched)
246{
247 mod_delayed_work(system_wq, &sched->work_tdr, 0);
248}
249EXPORT_SYMBOL(drm_sched_fault);
250
251/**
252 * drm_sched_suspend_timeout - Suspend scheduler job timeout
253 *
254 * @sched: scheduler instance for which to suspend the timeout
255 *
256 * Suspend the delayed work timeout for the scheduler. This is done by
257 * modifying the delayed work timeout to an arbitrary large value,
258 * MAX_SCHEDULE_TIMEOUT in this case.
259 *
260 * Returns the timeout remaining
261 *
262 */
263unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched)
264{
265 unsigned long sched_timeout, now = jiffies;
266
267 sched_timeout = sched->work_tdr.timer.expires;
268
269 /*
270 * Modify the timeout to an arbitrarily large value. This also prevents
271 * the timeout to be restarted when new submissions arrive
272 */
273 if (mod_delayed_work(system_wq, &sched->work_tdr, MAX_SCHEDULE_TIMEOUT)
274 && time_after(sched_timeout, now))
275 return sched_timeout - now;
276 else
277 return sched->timeout;
278}
279EXPORT_SYMBOL(drm_sched_suspend_timeout);
280
281/**
282 * drm_sched_resume_timeout - Resume scheduler job timeout
283 *
284 * @sched: scheduler instance for which to resume the timeout
285 * @remaining: remaining timeout
286 *
287 * Resume the delayed work timeout for the scheduler.
288 */
289void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
290 unsigned long remaining)
291{
292 spin_lock(&sched->job_list_lock);
293
294 if (list_empty(&sched->pending_list))
295 cancel_delayed_work(&sched->work_tdr);
296 else
297 mod_delayed_work(system_wq, &sched->work_tdr, remaining);
298
299 spin_unlock(&sched->job_list_lock);
300}
301EXPORT_SYMBOL(drm_sched_resume_timeout);
302
303static void drm_sched_job_begin(struct drm_sched_job *s_job)
304{
305 struct drm_gpu_scheduler *sched = s_job->sched;
306
307 spin_lock(&sched->job_list_lock);
308 list_add_tail(&s_job->list, &sched->pending_list);
309 drm_sched_start_timeout(sched);
310 spin_unlock(&sched->job_list_lock);
311}
312
313static void drm_sched_job_timedout(struct work_struct *work)
314{
315 struct drm_gpu_scheduler *sched;
316 struct drm_sched_job *job;
317 enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
318
319 sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
320
321 /* Protects against concurrent deletion in drm_sched_get_cleanup_job */
322 spin_lock(&sched->job_list_lock);
323 job = list_first_entry_or_null(&sched->pending_list,
324 struct drm_sched_job, list);
325
326 if (job) {
327 /*
328 * Remove the bad job so it cannot be freed by concurrent
329 * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
330 * is parked at which point it's safe.
331 */
332 list_del_init(&job->list);
333 spin_unlock(&sched->job_list_lock);
334
335 status = job->sched->ops->timedout_job(job);
336
337 /*
338 * Guilty job did complete and hence needs to be manually removed
339 * See drm_sched_stop doc.
340 */
341 if (sched->free_guilty) {
342 job->sched->ops->free_job(job);
343 sched->free_guilty = false;
344 }
345 } else {
346 spin_unlock(&sched->job_list_lock);
347 }
348
349 if (status != DRM_GPU_SCHED_STAT_ENODEV) {
350 spin_lock(&sched->job_list_lock);
351 drm_sched_start_timeout(sched);
352 spin_unlock(&sched->job_list_lock);
353 }
354}
355
356 /**
357 * drm_sched_increase_karma - Update sched_entity guilty flag
358 *
359 * @bad: The job guilty of time out
360 *
361 * Increment on every hang caused by the 'bad' job. If this exceeds the hang
362 * limit of the scheduler then the respective sched entity is marked guilty and
363 * jobs from it will not be scheduled further
364 */
365void drm_sched_increase_karma(struct drm_sched_job *bad)
366{
367 drm_sched_increase_karma_ext(bad, 1);
368}
369EXPORT_SYMBOL(drm_sched_increase_karma);
370
371void drm_sched_reset_karma(struct drm_sched_job *bad)
372{
373 drm_sched_increase_karma_ext(bad, 0);
374}
375EXPORT_SYMBOL(drm_sched_reset_karma);
376
377/**
378 * drm_sched_stop - stop the scheduler
379 *
380 * @sched: scheduler instance
381 * @bad: job which caused the time out
382 *
383 * Stop the scheduler and also removes and frees all completed jobs.
384 * Note: bad job will not be freed as it might be used later and so it's
385 * callers responsibility to release it manually if it's not part of the
386 * pending list any more.
387 *
388 */
389void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
390{
391 struct drm_sched_job *s_job, *tmp;
392
393 kthread_park(sched->thread);
394
395 /*
396 * Reinsert back the bad job here - now it's safe as
397 * drm_sched_get_cleanup_job cannot race against us and release the
398 * bad job at this point - we parked (waited for) any in progress
399 * (earlier) cleanups and drm_sched_get_cleanup_job will not be called
400 * now until the scheduler thread is unparked.
401 */
402 if (bad && bad->sched == sched)
403 /*
404 * Add at the head of the queue to reflect it was the earliest
405 * job extracted.
406 */
407 list_add(&bad->list, &sched->pending_list);
408
409 /*
410 * Iterate the job list from later to earlier one and either deactive
411 * their HW callbacks or remove them from pending list if they already
412 * signaled.
413 * This iteration is thread safe as sched thread is stopped.
414 */
415 list_for_each_entry_safe_reverse(s_job, tmp, &sched->pending_list,
416 list) {
417 if (s_job->s_fence->parent &&
418 dma_fence_remove_callback(s_job->s_fence->parent,
419 &s_job->cb)) {
420 atomic_dec(&sched->hw_rq_count);
421 } else {
422 /*
423 * remove job from pending_list.
424 * Locking here is for concurrent resume timeout
425 */
426 spin_lock(&sched->job_list_lock);
427 list_del_init(&s_job->list);
428 spin_unlock(&sched->job_list_lock);
429
430 /*
431 * Wait for job's HW fence callback to finish using s_job
432 * before releasing it.
433 *
434 * Job is still alive so fence refcount at least 1
435 */
436 dma_fence_wait(&s_job->s_fence->finished, false);
437
438 /*
439 * We must keep bad job alive for later use during
440 * recovery by some of the drivers but leave a hint
441 * that the guilty job must be released.
442 */
443 if (bad != s_job)
444 sched->ops->free_job(s_job);
445 else
446 sched->free_guilty = true;
447 }
448 }
449
450 /*
451 * Stop pending timer in flight as we rearm it in drm_sched_start. This
452 * avoids the pending timeout work in progress to fire right away after
453 * this TDR finished and before the newly restarted jobs had a
454 * chance to complete.
455 */
456 cancel_delayed_work(&sched->work_tdr);
457}
458
459EXPORT_SYMBOL(drm_sched_stop);
460
461/**
462 * drm_sched_start - recover jobs after a reset
463 *
464 * @sched: scheduler instance
465 * @full_recovery: proceed with complete sched restart
466 *
467 */
468void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
469{
470 struct drm_sched_job *s_job, *tmp;
471 int r;
472
473 /*
474 * Locking the list is not required here as the sched thread is parked
475 * so no new jobs are being inserted or removed. Also concurrent
476 * GPU recovers can't run in parallel.
477 */
478 list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
479 struct dma_fence *fence = s_job->s_fence->parent;
480
481 atomic_inc(&sched->hw_rq_count);
482
483 if (!full_recovery)
484 continue;
485
486 if (fence) {
487 r = dma_fence_add_callback(fence, &s_job->cb,
488 drm_sched_job_done_cb);
489 if (r == -ENOENT)
490 drm_sched_job_done(s_job);
491 else if (r)
492 DRM_ERROR("fence add callback failed (%d)\n",
493 r);
494 } else
495 drm_sched_job_done(s_job);
496 }
497
498 if (full_recovery) {
499 spin_lock(&sched->job_list_lock);
500 drm_sched_start_timeout(sched);
501 spin_unlock(&sched->job_list_lock);
502 }
503
504 kthread_unpark(sched->thread);
505}
506EXPORT_SYMBOL(drm_sched_start);
507
508/**
509 * drm_sched_resubmit_jobs - helper to relaunch jobs from the pending list
510 *
511 * @sched: scheduler instance
512 *
513 */
514void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
515{
516 drm_sched_resubmit_jobs_ext(sched, INT_MAX);
517}
518EXPORT_SYMBOL(drm_sched_resubmit_jobs);
519
520/**
521 * drm_sched_resubmit_jobs_ext - helper to relunch certain number of jobs from mirror ring list
522 *
523 * @sched: scheduler instance
524 * @max: job numbers to relaunch
525 *
526 */
527void drm_sched_resubmit_jobs_ext(struct drm_gpu_scheduler *sched, int max)
528{
529 struct drm_sched_job *s_job, *tmp;
530 uint64_t guilty_context;
531 bool found_guilty = false;
532 struct dma_fence *fence;
533 int i = 0;
534
535 list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
536 struct drm_sched_fence *s_fence = s_job->s_fence;
537
538 if (i >= max)
539 break;
540
541 if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
542 found_guilty = true;
543 guilty_context = s_job->s_fence->scheduled.context;
544 }
545
546 if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
547 dma_fence_set_error(&s_fence->finished, -ECANCELED);
548
549 dma_fence_put(s_job->s_fence->parent);
550 fence = sched->ops->run_job(s_job);
551 i++;
552
553 if (IS_ERR_OR_NULL(fence)) {
554 if (IS_ERR(fence))
555 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
556
557 s_job->s_fence->parent = NULL;
558 } else {
559 s_job->s_fence->parent = fence;
560 }
561 }
562}
563EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
564
565/**
566 * drm_sched_job_init - init a scheduler job
567 *
568 * @job: scheduler job to init
569 * @entity: scheduler entity to use
570 * @owner: job owner for debugging
571 *
572 * Refer to drm_sched_entity_push_job() documentation
573 * for locking considerations.
574 *
575 * Returns 0 for success, negative error code otherwise.
576 */
577int drm_sched_job_init(struct drm_sched_job *job,
578 struct drm_sched_entity *entity,
579 void *owner)
580{
581 struct drm_gpu_scheduler *sched;
582
583 drm_sched_entity_select_rq(entity);
584 if (!entity->rq)
585 return -ENOENT;
586
587 sched = entity->rq->sched;
588
589 job->sched = sched;
590 job->entity = entity;
591 job->s_priority = entity->rq - sched->sched_rq;
592 job->s_fence = drm_sched_fence_create(entity, owner);
593 if (!job->s_fence)
594 return -ENOMEM;
595 job->id = atomic64_inc_return(&sched->job_id_count);
596
597 INIT_LIST_HEAD(&job->list);
598
599 return 0;
600}
601EXPORT_SYMBOL(drm_sched_job_init);
602
603/**
604 * drm_sched_job_cleanup - clean up scheduler job resources
605 *
606 * @job: scheduler job to clean up
607 */
608void drm_sched_job_cleanup(struct drm_sched_job *job)
609{
610 dma_fence_put(&job->s_fence->finished);
611 job->s_fence = NULL;
612}
613EXPORT_SYMBOL(drm_sched_job_cleanup);
614
615/**
616 * drm_sched_ready - is the scheduler ready
617 *
618 * @sched: scheduler instance
619 *
620 * Return true if we can push more jobs to the hw, otherwise false.
621 */
622static bool drm_sched_ready(struct drm_gpu_scheduler *sched)
623{
624 return atomic_read(&sched->hw_rq_count) <
625 sched->hw_submission_limit;
626}
627
628/**
629 * drm_sched_wakeup - Wake up the scheduler when it is ready
630 *
631 * @sched: scheduler instance
632 *
633 */
634void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
635{
636 if (drm_sched_ready(sched))
637 wake_up_interruptible(&sched->wake_up_worker);
638}
639
640/**
641 * drm_sched_select_entity - Select next entity to process
642 *
643 * @sched: scheduler instance
644 *
645 * Returns the entity to process or NULL if none are found.
646 */
647static struct drm_sched_entity *
648drm_sched_select_entity(struct drm_gpu_scheduler *sched)
649{
650 struct drm_sched_entity *entity;
651 int i;
652
653 if (!drm_sched_ready(sched))
654 return NULL;
655
656 /* Kernel run queue has higher priority than normal run queue*/
657 for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
658 entity = drm_sched_rq_select_entity(&sched->sched_rq[i]);
659 if (entity)
660 break;
661 }
662
663 return entity;
664}
665
666/**
667 * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
668 *
669 * @sched: scheduler instance
670 *
671 * Returns the next finished job from the pending list (if there is one)
672 * ready for it to be destroyed.
673 */
674static struct drm_sched_job *
675drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
676{
677 struct drm_sched_job *job, *next;
678
679 /*
680 * Don't destroy jobs while the timeout worker is running OR thread
681 * is being parked and hence assumed to not touch pending_list
682 */
683 if ((sched->timeout != MAX_SCHEDULE_TIMEOUT &&
684 !cancel_delayed_work(&sched->work_tdr)) ||
685 kthread_should_park())
686 return NULL;
687
688 spin_lock(&sched->job_list_lock);
689
690 job = list_first_entry_or_null(&sched->pending_list,
691 struct drm_sched_job, list);
692
693 if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
694 /* remove job from pending_list */
695 list_del_init(&job->list);
696 /* make the scheduled timestamp more accurate */
697 next = list_first_entry_or_null(&sched->pending_list,
698 typeof(*next), list);
699 if (next)
700 next->s_fence->scheduled.timestamp =
701 job->s_fence->finished.timestamp;
702
703 } else {
704 job = NULL;
705 /* queue timeout for next job */
706 drm_sched_start_timeout(sched);
707 }
708
709 spin_unlock(&sched->job_list_lock);
710
711 return job;
712}
713
714/**
715 * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
716 * @sched_list: list of drm_gpu_schedulers
717 * @num_sched_list: number of drm_gpu_schedulers in the sched_list
718 *
719 * Returns pointer of the sched with the least load or NULL if none of the
720 * drm_gpu_schedulers are ready
721 */
722struct drm_gpu_scheduler *
723drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
724 unsigned int num_sched_list)
725{
726 struct drm_gpu_scheduler *sched, *picked_sched = NULL;
727 int i;
728 unsigned int min_score = UINT_MAX, num_score;
729
730 for (i = 0; i < num_sched_list; ++i) {
731 sched = sched_list[i];
732
733 if (!sched->ready) {
734 DRM_WARN("scheduler %s is not ready, skipping",
735 sched->name);
736 continue;
737 }
738
739 num_score = atomic_read(sched->score);
740 if (num_score < min_score) {
741 min_score = num_score;
742 picked_sched = sched;
743 }
744 }
745
746 return picked_sched;
747}
748EXPORT_SYMBOL(drm_sched_pick_best);
749
750/**
751 * drm_sched_blocked - check if the scheduler is blocked
752 *
753 * @sched: scheduler instance
754 *
755 * Returns true if blocked, otherwise false.
756 */
757static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
758{
759 if (kthread_should_park()) {
760 kthread_parkme();
761 return true;
762 }
763
764 return false;
765}
766
767/**
768 * drm_sched_main - main scheduler thread
769 *
770 * @param: scheduler instance
771 *
772 * Returns 0.
773 */
774static int drm_sched_main(void *param)
775{
776 struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
777 int r;
778
779 sched_set_fifo_low(current);
780
781 while (!kthread_should_stop()) {
782 struct drm_sched_entity *entity = NULL;
783 struct drm_sched_fence *s_fence;
784 struct drm_sched_job *sched_job;
785 struct dma_fence *fence;
786 struct drm_sched_job *cleanup_job = NULL;
787
788 wait_event_interruptible(sched->wake_up_worker,
789 (cleanup_job = drm_sched_get_cleanup_job(sched)) ||
790 (!drm_sched_blocked(sched) &&
791 (entity = drm_sched_select_entity(sched))) ||
792 kthread_should_stop());
793
794 if (cleanup_job) {
795 sched->ops->free_job(cleanup_job);
796 /* queue timeout for next job */
797 drm_sched_start_timeout(sched);
798 }
799
800 if (!entity)
801 continue;
802
803 sched_job = drm_sched_entity_pop_job(entity);
804
805 complete(&entity->entity_idle);
806
807 if (!sched_job)
808 continue;
809
810 s_fence = sched_job->s_fence;
811
812 atomic_inc(&sched->hw_rq_count);
813 drm_sched_job_begin(sched_job);
814
815 trace_drm_run_job(sched_job, entity);
816 fence = sched->ops->run_job(sched_job);
817 drm_sched_fence_scheduled(s_fence);
818
819 if (!IS_ERR_OR_NULL(fence)) {
820 s_fence->parent = dma_fence_get(fence);
821 r = dma_fence_add_callback(fence, &sched_job->cb,
822 drm_sched_job_done_cb);
823 if (r == -ENOENT)
824 drm_sched_job_done(sched_job);
825 else if (r)
826 DRM_ERROR("fence add callback failed (%d)\n",
827 r);
828 dma_fence_put(fence);
829 } else {
830 if (IS_ERR(fence))
831 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
832
833 drm_sched_job_done(sched_job);
834 }
835
836 wake_up(&sched->job_scheduled);
837 }
838 return 0;
839}
840
841/**
842 * drm_sched_init - Init a gpu scheduler instance
843 *
844 * @sched: scheduler instance
845 * @ops: backend operations for this scheduler
846 * @hw_submission: number of hw submissions that can be in flight
847 * @hang_limit: number of times to allow a job to hang before dropping it
848 * @timeout: timeout value in jiffies for the scheduler
849 * @score: optional score atomic shared with other schedulers
850 * @name: name used for debugging
851 *
852 * Return 0 on success, otherwise error code.
853 */
854int drm_sched_init(struct drm_gpu_scheduler *sched,
855 const struct drm_sched_backend_ops *ops,
856 unsigned hw_submission, unsigned hang_limit, long timeout,
857 atomic_t *score, const char *name)
858{
859 int i, ret;
860 sched->ops = ops;
861 sched->hw_submission_limit = hw_submission;
862 sched->name = name;
863 sched->timeout = timeout;
864 sched->hang_limit = hang_limit;
865 sched->score = score ? score : &sched->_score;
866 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; i++)
867 drm_sched_rq_init(sched, &sched->sched_rq[i]);
868
869 init_waitqueue_head(&sched->wake_up_worker);
870 init_waitqueue_head(&sched->job_scheduled);
871 INIT_LIST_HEAD(&sched->pending_list);
872 spin_lock_init(&sched->job_list_lock);
873 atomic_set(&sched->hw_rq_count, 0);
874 INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
875 atomic_set(&sched->_score, 0);
876 atomic64_set(&sched->job_id_count, 0);
877
878 /* Each scheduler will run on a seperate kernel thread */
879 sched->thread = kthread_run(drm_sched_main, sched, sched->name);
880 if (IS_ERR(sched->thread)) {
881 ret = PTR_ERR(sched->thread);
882 sched->thread = NULL;
883 DRM_ERROR("Failed to create scheduler for %s.\n", name);
884 return ret;
885 }
886
887 sched->ready = true;
888 return 0;
889}
890EXPORT_SYMBOL(drm_sched_init);
891
892/**
893 * drm_sched_fini - Destroy a gpu scheduler
894 *
895 * @sched: scheduler instance
896 *
897 * Tears down and cleans up the scheduler.
898 */
899void drm_sched_fini(struct drm_gpu_scheduler *sched)
900{
901 struct drm_sched_entity *s_entity;
902 int i;
903
904 if (sched->thread)
905 kthread_stop(sched->thread);
906
907 for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
908 struct drm_sched_rq *rq = &sched->sched_rq[i];
909
910 if (!rq)
911 continue;
912
913 spin_lock(&rq->lock);
914 list_for_each_entry(s_entity, &rq->entities, list)
915 /*
916 * Prevents reinsertion and marks job_queue as idle,
917 * it will removed from rq in drm_sched_entity_fini
918 * eventually
919 */
920 s_entity->stopped = true;
921 spin_unlock(&rq->lock);
922
923 }
924
925 /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
926 wake_up_all(&sched->job_scheduled);
927
928 /* Confirm no work left behind accessing device structures */
929 cancel_delayed_work_sync(&sched->work_tdr);
930
931 sched->ready = false;
932}
933EXPORT_SYMBOL(drm_sched_fini);
934
935/**
936 * drm_sched_increase_karma_ext - Update sched_entity guilty flag
937 *
938 * @bad: The job guilty of time out
939 * @type: type for increase/reset karma
940 *
941 */
942void drm_sched_increase_karma_ext(struct drm_sched_job *bad, int type)
943{
944 int i;
945 struct drm_sched_entity *tmp;
946 struct drm_sched_entity *entity;
947 struct drm_gpu_scheduler *sched = bad->sched;
948
949 /* don't change @bad's karma if it's from KERNEL RQ,
950 * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
951 * corrupt but keep in mind that kernel jobs always considered good.
952 */
953 if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
954 if (type == 0)
955 atomic_set(&bad->karma, 0);
956 else if (type == 1)
957 atomic_inc(&bad->karma);
958
959 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
960 i++) {
961 struct drm_sched_rq *rq = &sched->sched_rq[i];
962
963 spin_lock(&rq->lock);
964 list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
965 if (bad->s_fence->scheduled.context ==
966 entity->fence_context) {
967 if (entity->guilty)
968 atomic_set(entity->guilty, type);
969 break;
970 }
971 }
972 spin_unlock(&rq->lock);
973 if (&entity->list != &rq->entities)
974 break;
975 }
976 }
977}
978EXPORT_SYMBOL(drm_sched_increase_karma_ext);