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 */
drm_sched_rq_init(struct drm_gpu_scheduler * sched,struct drm_sched_rq * rq)71 static 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 */
drm_sched_rq_add_entity(struct drm_sched_rq * rq,struct drm_sched_entity * entity)88 void 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 */
drm_sched_rq_remove_entity(struct drm_sched_rq * rq,struct drm_sched_entity * entity)107 void 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 */
127 static struct drm_sched_entity *
drm_sched_rq_select_entity(struct drm_sched_rq * rq)128 drm_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 */
drm_sched_job_done(struct drm_sched_job * s_job)170 static 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 */
drm_sched_job_done_cb(struct dma_fence * f,struct dma_fence_cb * cb)191 static 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 */
drm_sched_dependency_optimized(struct dma_fence * fence,struct drm_sched_entity * entity)206 bool 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 }
222 EXPORT_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 */
drm_sched_start_timeout(struct drm_gpu_scheduler * sched)231 static 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 queue_delayed_work(sched->timeout_wq, &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 */
drm_sched_fault(struct drm_gpu_scheduler * sched)245 void drm_sched_fault(struct drm_gpu_scheduler *sched)
246 {
247 mod_delayed_work(sched->timeout_wq, &sched->work_tdr, 0);
248 }
249 EXPORT_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 */
drm_sched_suspend_timeout(struct drm_gpu_scheduler * sched)263 unsigned 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(sched->timeout_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 }
279 EXPORT_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 */
drm_sched_resume_timeout(struct drm_gpu_scheduler * sched,unsigned long remaining)289 void 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(sched->timeout_wq, &sched->work_tdr, remaining);
298
299 spin_unlock(&sched->job_list_lock);
300 }
301 EXPORT_SYMBOL(drm_sched_resume_timeout);
302
drm_sched_job_begin(struct drm_sched_job * s_job)303 static 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
drm_sched_job_timedout(struct work_struct * work)313 static 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 */
drm_sched_increase_karma(struct drm_sched_job * bad)365 void drm_sched_increase_karma(struct drm_sched_job *bad)
366 {
367 drm_sched_increase_karma_ext(bad, 1);
368 }
369 EXPORT_SYMBOL(drm_sched_increase_karma);
370
drm_sched_reset_karma(struct drm_sched_job * bad)371 void drm_sched_reset_karma(struct drm_sched_job *bad)
372 {
373 drm_sched_increase_karma_ext(bad, 0);
374 }
375 EXPORT_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 */
drm_sched_stop(struct drm_gpu_scheduler * sched,struct drm_sched_job * bad)389 void 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
459 EXPORT_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 */
drm_sched_start(struct drm_gpu_scheduler * sched,bool full_recovery)468 void 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 }
506 EXPORT_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 */
drm_sched_resubmit_jobs(struct drm_gpu_scheduler * sched)514 void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
515 {
516 drm_sched_resubmit_jobs_ext(sched, INT_MAX);
517 }
518 EXPORT_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 */
drm_sched_resubmit_jobs_ext(struct drm_gpu_scheduler * sched,int max)527 void 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 }
563 EXPORT_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 */
drm_sched_job_init(struct drm_sched_job * job,struct drm_sched_entity * entity,void * owner)577 int 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 }
601 EXPORT_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 */
drm_sched_job_cleanup(struct drm_sched_job * job)608 void drm_sched_job_cleanup(struct drm_sched_job *job)
609 {
610 dma_fence_put(&job->s_fence->finished);
611 job->s_fence = NULL;
612 }
613 EXPORT_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 */
drm_sched_ready(struct drm_gpu_scheduler * sched)622 static 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 */
drm_sched_wakeup(struct drm_gpu_scheduler * sched)634 void 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 */
647 static struct drm_sched_entity *
drm_sched_select_entity(struct drm_gpu_scheduler * sched)648 drm_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 */
674 static struct drm_sched_job *
drm_sched_get_cleanup_job(struct drm_gpu_scheduler * sched)675 drm_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 */
722 struct drm_gpu_scheduler *
drm_sched_pick_best(struct drm_gpu_scheduler ** sched_list,unsigned int num_sched_list)723 drm_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 }
748 EXPORT_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 */
drm_sched_blocked(struct drm_gpu_scheduler * sched)757 static 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 */
drm_sched_main(void * param)774 static 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 if (!sched_job) {
806 complete(&entity->entity_idle);
807 continue;
808 }
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 complete(&entity->entity_idle);
818 drm_sched_fence_scheduled(s_fence);
819
820 if (!IS_ERR_OR_NULL(fence)) {
821 s_fence->parent = dma_fence_get(fence);
822 r = dma_fence_add_callback(fence, &sched_job->cb,
823 drm_sched_job_done_cb);
824 if (r == -ENOENT)
825 drm_sched_job_done(sched_job);
826 else if (r)
827 DRM_ERROR("fence add callback failed (%d)\n",
828 r);
829 dma_fence_put(fence);
830 } else {
831 if (IS_ERR(fence))
832 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
833
834 drm_sched_job_done(sched_job);
835 }
836
837 wake_up(&sched->job_scheduled);
838 }
839 return 0;
840 }
841
842 /**
843 * drm_sched_init - Init a gpu scheduler instance
844 *
845 * @sched: scheduler instance
846 * @ops: backend operations for this scheduler
847 * @hw_submission: number of hw submissions that can be in flight
848 * @hang_limit: number of times to allow a job to hang before dropping it
849 * @timeout: timeout value in jiffies for the scheduler
850 * @timeout_wq: workqueue to use for timeout work. If NULL, the system_wq is
851 * used
852 * @score: optional score atomic shared with other schedulers
853 * @name: name used for debugging
854 *
855 * Return 0 on success, otherwise error code.
856 */
drm_sched_init(struct drm_gpu_scheduler * sched,const struct drm_sched_backend_ops * ops,unsigned hw_submission,unsigned hang_limit,long timeout,struct workqueue_struct * timeout_wq,atomic_t * score,const char * name)857 int drm_sched_init(struct drm_gpu_scheduler *sched,
858 const struct drm_sched_backend_ops *ops,
859 unsigned hw_submission, unsigned hang_limit,
860 long timeout, struct workqueue_struct *timeout_wq,
861 atomic_t *score, const char *name)
862 {
863 int i, ret;
864 sched->ops = ops;
865 sched->hw_submission_limit = hw_submission;
866 sched->name = name;
867 sched->timeout = timeout;
868 sched->timeout_wq = timeout_wq ? : system_wq;
869 sched->hang_limit = hang_limit;
870 sched->score = score ? score : &sched->_score;
871 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; i++)
872 drm_sched_rq_init(sched, &sched->sched_rq[i]);
873
874 init_waitqueue_head(&sched->wake_up_worker);
875 init_waitqueue_head(&sched->job_scheduled);
876 INIT_LIST_HEAD(&sched->pending_list);
877 spin_lock_init(&sched->job_list_lock);
878 atomic_set(&sched->hw_rq_count, 0);
879 INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
880 atomic_set(&sched->_score, 0);
881 atomic64_set(&sched->job_id_count, 0);
882
883 /* Each scheduler will run on a seperate kernel thread */
884 sched->thread = kthread_run(drm_sched_main, sched, sched->name);
885 if (IS_ERR(sched->thread)) {
886 ret = PTR_ERR(sched->thread);
887 sched->thread = NULL;
888 DRM_ERROR("Failed to create scheduler for %s.\n", name);
889 return ret;
890 }
891
892 sched->ready = true;
893 return 0;
894 }
895 EXPORT_SYMBOL(drm_sched_init);
896
897 /**
898 * drm_sched_fini - Destroy a gpu scheduler
899 *
900 * @sched: scheduler instance
901 *
902 * Tears down and cleans up the scheduler.
903 */
drm_sched_fini(struct drm_gpu_scheduler * sched)904 void drm_sched_fini(struct drm_gpu_scheduler *sched)
905 {
906 struct drm_sched_entity *s_entity;
907 int i;
908
909 if (sched->thread)
910 kthread_stop(sched->thread);
911
912 for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
913 struct drm_sched_rq *rq = &sched->sched_rq[i];
914
915 if (!rq)
916 continue;
917
918 spin_lock(&rq->lock);
919 list_for_each_entry(s_entity, &rq->entities, list)
920 /*
921 * Prevents reinsertion and marks job_queue as idle,
922 * it will removed from rq in drm_sched_entity_fini
923 * eventually
924 */
925 s_entity->stopped = true;
926 spin_unlock(&rq->lock);
927
928 }
929
930 /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
931 wake_up_all(&sched->job_scheduled);
932
933 /* Confirm no work left behind accessing device structures */
934 cancel_delayed_work_sync(&sched->work_tdr);
935
936 sched->ready = false;
937 }
938 EXPORT_SYMBOL(drm_sched_fini);
939
940 /**
941 * drm_sched_increase_karma_ext - Update sched_entity guilty flag
942 *
943 * @bad: The job guilty of time out
944 * @type: type for increase/reset karma
945 *
946 */
drm_sched_increase_karma_ext(struct drm_sched_job * bad,int type)947 void drm_sched_increase_karma_ext(struct drm_sched_job *bad, int type)
948 {
949 int i;
950 struct drm_sched_entity *tmp;
951 struct drm_sched_entity *entity;
952 struct drm_gpu_scheduler *sched = bad->sched;
953
954 /* don't change @bad's karma if it's from KERNEL RQ,
955 * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
956 * corrupt but keep in mind that kernel jobs always considered good.
957 */
958 if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
959 if (type == 0)
960 atomic_set(&bad->karma, 0);
961 else if (type == 1)
962 atomic_inc(&bad->karma);
963
964 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
965 i++) {
966 struct drm_sched_rq *rq = &sched->sched_rq[i];
967
968 spin_lock(&rq->lock);
969 list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
970 if (bad->s_fence->scheduled.context ==
971 entity->fence_context) {
972 if (entity->guilty)
973 atomic_set(entity->guilty, type);
974 break;
975 }
976 }
977 spin_unlock(&rq->lock);
978 if (&entity->list != &rq->entities)
979 break;
980 }
981 }
982 }
983 EXPORT_SYMBOL(drm_sched_increase_karma_ext);
984