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 static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb);
64
65 /**
66 * drm_sched_rq_init - initialize a given run queue struct
67 *
68 * @rq: scheduler run queue
69 *
70 * Initializes a scheduler runqueue.
71 */
drm_sched_rq_init(struct drm_gpu_scheduler * sched,struct drm_sched_rq * rq)72 static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
73 struct drm_sched_rq *rq)
74 {
75 spin_lock_init(&rq->lock);
76 INIT_LIST_HEAD(&rq->entities);
77 rq->current_entity = NULL;
78 rq->sched = sched;
79 }
80
81 /**
82 * drm_sched_rq_add_entity - add an entity
83 *
84 * @rq: scheduler run queue
85 * @entity: scheduler entity
86 *
87 * Adds a scheduler entity to the run queue.
88 */
drm_sched_rq_add_entity(struct drm_sched_rq * rq,struct drm_sched_entity * entity)89 void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
90 struct drm_sched_entity *entity)
91 {
92 if (!list_empty(&entity->list))
93 return;
94 spin_lock(&rq->lock);
95 atomic_inc(&rq->sched->score);
96 list_add_tail(&entity->list, &rq->entities);
97 spin_unlock(&rq->lock);
98 }
99
100 /**
101 * drm_sched_rq_remove_entity - remove an entity
102 *
103 * @rq: scheduler run queue
104 * @entity: scheduler entity
105 *
106 * Removes a scheduler entity from the run queue.
107 */
drm_sched_rq_remove_entity(struct drm_sched_rq * rq,struct drm_sched_entity * entity)108 void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
109 struct drm_sched_entity *entity)
110 {
111 if (list_empty(&entity->list))
112 return;
113 spin_lock(&rq->lock);
114 atomic_dec(&rq->sched->score);
115 list_del_init(&entity->list);
116 if (rq->current_entity == entity)
117 rq->current_entity = NULL;
118 spin_unlock(&rq->lock);
119 }
120
121 /**
122 * drm_sched_rq_select_entity - Select an entity which could provide a job to run
123 *
124 * @rq: scheduler run queue to check.
125 *
126 * Try to find a ready entity, returns NULL if none found.
127 */
128 static struct drm_sched_entity *
drm_sched_rq_select_entity(struct drm_sched_rq * rq)129 drm_sched_rq_select_entity(struct drm_sched_rq *rq)
130 {
131 struct drm_sched_entity *entity;
132
133 spin_lock(&rq->lock);
134
135 entity = rq->current_entity;
136 if (entity) {
137 list_for_each_entry_continue(entity, &rq->entities, list) {
138 if (drm_sched_entity_is_ready(entity)) {
139 rq->current_entity = entity;
140 reinit_completion(&entity->entity_idle);
141 spin_unlock(&rq->lock);
142 return entity;
143 }
144 }
145 }
146
147 list_for_each_entry(entity, &rq->entities, list) {
148
149 if (drm_sched_entity_is_ready(entity)) {
150 rq->current_entity = entity;
151 reinit_completion(&entity->entity_idle);
152 spin_unlock(&rq->lock);
153 return entity;
154 }
155
156 if (entity == rq->current_entity)
157 break;
158 }
159
160 spin_unlock(&rq->lock);
161
162 return NULL;
163 }
164
165 /**
166 * drm_sched_dependency_optimized
167 *
168 * @fence: the dependency fence
169 * @entity: the entity which depends on the above fence
170 *
171 * Returns true if the dependency can be optimized and false otherwise
172 */
drm_sched_dependency_optimized(struct dma_fence * fence,struct drm_sched_entity * entity)173 bool drm_sched_dependency_optimized(struct dma_fence* fence,
174 struct drm_sched_entity *entity)
175 {
176 struct drm_gpu_scheduler *sched = entity->rq->sched;
177 struct drm_sched_fence *s_fence;
178
179 if (!fence || dma_fence_is_signaled(fence))
180 return false;
181 if (fence->context == entity->fence_context)
182 return true;
183 s_fence = to_drm_sched_fence(fence);
184 if (s_fence && s_fence->sched == sched)
185 return true;
186
187 return false;
188 }
189 EXPORT_SYMBOL(drm_sched_dependency_optimized);
190
191 /**
192 * drm_sched_start_timeout - start timeout for reset worker
193 *
194 * @sched: scheduler instance to start the worker for
195 *
196 * Start the timeout for the given scheduler.
197 */
drm_sched_start_timeout(struct drm_gpu_scheduler * sched)198 static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched)
199 {
200 if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
201 !list_empty(&sched->ring_mirror_list))
202 schedule_delayed_work(&sched->work_tdr, sched->timeout);
203 }
204
205 /**
206 * drm_sched_fault - immediately start timeout handler
207 *
208 * @sched: scheduler where the timeout handling should be started.
209 *
210 * Start timeout handling immediately when the driver detects a hardware fault.
211 */
drm_sched_fault(struct drm_gpu_scheduler * sched)212 void drm_sched_fault(struct drm_gpu_scheduler *sched)
213 {
214 mod_delayed_work(system_wq, &sched->work_tdr, 0);
215 }
216 EXPORT_SYMBOL(drm_sched_fault);
217
218 /**
219 * drm_sched_suspend_timeout - Suspend scheduler job timeout
220 *
221 * @sched: scheduler instance for which to suspend the timeout
222 *
223 * Suspend the delayed work timeout for the scheduler. This is done by
224 * modifying the delayed work timeout to an arbitrary large value,
225 * MAX_SCHEDULE_TIMEOUT in this case.
226 *
227 * Returns the timeout remaining
228 *
229 */
drm_sched_suspend_timeout(struct drm_gpu_scheduler * sched)230 unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched)
231 {
232 unsigned long sched_timeout, now = jiffies;
233
234 sched_timeout = sched->work_tdr.timer.expires;
235
236 /*
237 * Modify the timeout to an arbitrarily large value. This also prevents
238 * the timeout to be restarted when new submissions arrive
239 */
240 if (mod_delayed_work(system_wq, &sched->work_tdr, MAX_SCHEDULE_TIMEOUT)
241 && time_after(sched_timeout, now))
242 return sched_timeout - now;
243 else
244 return sched->timeout;
245 }
246 EXPORT_SYMBOL(drm_sched_suspend_timeout);
247
248 /**
249 * drm_sched_resume_timeout - Resume scheduler job timeout
250 *
251 * @sched: scheduler instance for which to resume the timeout
252 * @remaining: remaining timeout
253 *
254 * Resume the delayed work timeout for the scheduler.
255 */
drm_sched_resume_timeout(struct drm_gpu_scheduler * sched,unsigned long remaining)256 void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
257 unsigned long remaining)
258 {
259 spin_lock(&sched->job_list_lock);
260
261 if (list_empty(&sched->ring_mirror_list))
262 cancel_delayed_work(&sched->work_tdr);
263 else
264 mod_delayed_work(system_wq, &sched->work_tdr, remaining);
265
266 spin_unlock(&sched->job_list_lock);
267 }
268 EXPORT_SYMBOL(drm_sched_resume_timeout);
269
drm_sched_job_begin(struct drm_sched_job * s_job)270 static void drm_sched_job_begin(struct drm_sched_job *s_job)
271 {
272 struct drm_gpu_scheduler *sched = s_job->sched;
273
274 spin_lock(&sched->job_list_lock);
275 list_add_tail(&s_job->node, &sched->ring_mirror_list);
276 drm_sched_start_timeout(sched);
277 spin_unlock(&sched->job_list_lock);
278 }
279
drm_sched_job_timedout(struct work_struct * work)280 static void drm_sched_job_timedout(struct work_struct *work)
281 {
282 struct drm_gpu_scheduler *sched;
283 struct drm_sched_job *job;
284
285 sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
286
287 /* Protects against concurrent deletion in drm_sched_get_cleanup_job */
288 spin_lock(&sched->job_list_lock);
289 job = list_first_entry_or_null(&sched->ring_mirror_list,
290 struct drm_sched_job, node);
291
292 if (job) {
293 /*
294 * Remove the bad job so it cannot be freed by concurrent
295 * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
296 * is parked at which point it's safe.
297 */
298 list_del_init(&job->node);
299 spin_unlock(&sched->job_list_lock);
300
301 job->sched->ops->timedout_job(job);
302
303 /*
304 * Guilty job did complete and hence needs to be manually removed
305 * See drm_sched_stop doc.
306 */
307 if (sched->free_guilty) {
308 job->sched->ops->free_job(job);
309 sched->free_guilty = false;
310 }
311 } else {
312 spin_unlock(&sched->job_list_lock);
313 }
314
315 spin_lock(&sched->job_list_lock);
316 drm_sched_start_timeout(sched);
317 spin_unlock(&sched->job_list_lock);
318 }
319
320 /**
321 * drm_sched_increase_karma - Update sched_entity guilty flag
322 *
323 * @bad: The job guilty of time out
324 *
325 * Increment on every hang caused by the 'bad' job. If this exceeds the hang
326 * limit of the scheduler then the respective sched entity is marked guilty and
327 * jobs from it will not be scheduled further
328 */
drm_sched_increase_karma(struct drm_sched_job * bad)329 void drm_sched_increase_karma(struct drm_sched_job *bad)
330 {
331 int i;
332 struct drm_sched_entity *tmp;
333 struct drm_sched_entity *entity;
334 struct drm_gpu_scheduler *sched = bad->sched;
335
336 /* don't increase @bad's karma if it's from KERNEL RQ,
337 * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
338 * corrupt but keep in mind that kernel jobs always considered good.
339 */
340 if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
341 atomic_inc(&bad->karma);
342 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
343 i++) {
344 struct drm_sched_rq *rq = &sched->sched_rq[i];
345
346 spin_lock(&rq->lock);
347 list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
348 if (bad->s_fence->scheduled.context ==
349 entity->fence_context) {
350 if (atomic_read(&bad->karma) >
351 bad->sched->hang_limit)
352 if (entity->guilty)
353 atomic_set(entity->guilty, 1);
354 break;
355 }
356 }
357 spin_unlock(&rq->lock);
358 if (&entity->list != &rq->entities)
359 break;
360 }
361 }
362 }
363 EXPORT_SYMBOL(drm_sched_increase_karma);
364
365 /**
366 * drm_sched_stop - stop the scheduler
367 *
368 * @sched: scheduler instance
369 * @bad: job which caused the time out
370 *
371 * Stop the scheduler and also removes and frees all completed jobs.
372 * Note: bad job will not be freed as it might be used later and so it's
373 * callers responsibility to release it manually if it's not part of the
374 * mirror list any more.
375 *
376 */
drm_sched_stop(struct drm_gpu_scheduler * sched,struct drm_sched_job * bad)377 void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
378 {
379 struct drm_sched_job *s_job, *tmp;
380
381 kthread_park(sched->thread);
382
383 /*
384 * Reinsert back the bad job here - now it's safe as
385 * drm_sched_get_cleanup_job cannot race against us and release the
386 * bad job at this point - we parked (waited for) any in progress
387 * (earlier) cleanups and drm_sched_get_cleanup_job will not be called
388 * now until the scheduler thread is unparked.
389 */
390 if (bad && bad->sched == sched)
391 /*
392 * Add at the head of the queue to reflect it was the earliest
393 * job extracted.
394 */
395 list_add(&bad->node, &sched->ring_mirror_list);
396
397 /*
398 * Iterate the job list from later to earlier one and either deactive
399 * their HW callbacks or remove them from mirror list if they already
400 * signaled.
401 * This iteration is thread safe as sched thread is stopped.
402 */
403 list_for_each_entry_safe_reverse(s_job, tmp, &sched->ring_mirror_list, node) {
404 if (s_job->s_fence->parent &&
405 dma_fence_remove_callback(s_job->s_fence->parent,
406 &s_job->cb)) {
407 atomic_dec(&sched->hw_rq_count);
408 } else {
409 /*
410 * remove job from ring_mirror_list.
411 * Locking here is for concurrent resume timeout
412 */
413 spin_lock(&sched->job_list_lock);
414 list_del_init(&s_job->node);
415 spin_unlock(&sched->job_list_lock);
416
417 /*
418 * Wait for job's HW fence callback to finish using s_job
419 * before releasing it.
420 *
421 * Job is still alive so fence refcount at least 1
422 */
423 dma_fence_wait(&s_job->s_fence->finished, false);
424
425 /*
426 * We must keep bad job alive for later use during
427 * recovery by some of the drivers but leave a hint
428 * that the guilty job must be released.
429 */
430 if (bad != s_job)
431 sched->ops->free_job(s_job);
432 else
433 sched->free_guilty = true;
434 }
435 }
436
437 /*
438 * Stop pending timer in flight as we rearm it in drm_sched_start. This
439 * avoids the pending timeout work in progress to fire right away after
440 * this TDR finished and before the newly restarted jobs had a
441 * chance to complete.
442 */
443 cancel_delayed_work(&sched->work_tdr);
444 }
445
446 EXPORT_SYMBOL(drm_sched_stop);
447
448 /**
449 * drm_sched_job_recovery - recover jobs after a reset
450 *
451 * @sched: scheduler instance
452 * @full_recovery: proceed with complete sched restart
453 *
454 */
drm_sched_start(struct drm_gpu_scheduler * sched,bool full_recovery)455 void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
456 {
457 struct drm_sched_job *s_job, *tmp;
458 int r;
459
460 /*
461 * Locking the list is not required here as the sched thread is parked
462 * so no new jobs are being inserted or removed. Also concurrent
463 * GPU recovers can't run in parallel.
464 */
465 list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
466 struct dma_fence *fence = s_job->s_fence->parent;
467
468 atomic_inc(&sched->hw_rq_count);
469
470 if (!full_recovery)
471 continue;
472
473 if (fence) {
474 r = dma_fence_add_callback(fence, &s_job->cb,
475 drm_sched_process_job);
476 if (r == -ENOENT)
477 drm_sched_process_job(fence, &s_job->cb);
478 else if (r)
479 DRM_ERROR("fence add callback failed (%d)\n",
480 r);
481 } else
482 drm_sched_process_job(NULL, &s_job->cb);
483 }
484
485 if (full_recovery) {
486 spin_lock(&sched->job_list_lock);
487 drm_sched_start_timeout(sched);
488 spin_unlock(&sched->job_list_lock);
489 }
490
491 kthread_unpark(sched->thread);
492 }
493 EXPORT_SYMBOL(drm_sched_start);
494
495 /**
496 * drm_sched_resubmit_jobs - helper to relunch job from mirror ring list
497 *
498 * @sched: scheduler instance
499 *
500 */
drm_sched_resubmit_jobs(struct drm_gpu_scheduler * sched)501 void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
502 {
503 struct drm_sched_job *s_job, *tmp;
504 uint64_t guilty_context;
505 bool found_guilty = false;
506 struct dma_fence *fence;
507
508 list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
509 struct drm_sched_fence *s_fence = s_job->s_fence;
510
511 if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
512 found_guilty = true;
513 guilty_context = s_job->s_fence->scheduled.context;
514 }
515
516 if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
517 dma_fence_set_error(&s_fence->finished, -ECANCELED);
518
519 dma_fence_put(s_job->s_fence->parent);
520 fence = sched->ops->run_job(s_job);
521
522 if (IS_ERR_OR_NULL(fence)) {
523 if (IS_ERR(fence))
524 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
525
526 s_job->s_fence->parent = NULL;
527 } else {
528 s_job->s_fence->parent = fence;
529 }
530
531
532 }
533 }
534 EXPORT_SYMBOL(drm_sched_resubmit_jobs);
535
536 /**
537 * drm_sched_job_init - init a scheduler job
538 *
539 * @job: scheduler job to init
540 * @entity: scheduler entity to use
541 * @owner: job owner for debugging
542 *
543 * Refer to drm_sched_entity_push_job() documentation
544 * for locking considerations.
545 *
546 * Returns 0 for success, negative error code otherwise.
547 */
drm_sched_job_init(struct drm_sched_job * job,struct drm_sched_entity * entity,void * owner)548 int drm_sched_job_init(struct drm_sched_job *job,
549 struct drm_sched_entity *entity,
550 void *owner)
551 {
552 struct drm_gpu_scheduler *sched;
553
554 drm_sched_entity_select_rq(entity);
555 if (!entity->rq)
556 return -ENOENT;
557
558 sched = entity->rq->sched;
559
560 job->sched = sched;
561 job->entity = entity;
562 job->s_priority = entity->rq - sched->sched_rq;
563 job->s_fence = drm_sched_fence_create(entity, owner);
564 if (!job->s_fence)
565 return -ENOMEM;
566 job->id = atomic64_inc_return(&sched->job_id_count);
567
568 INIT_LIST_HEAD(&job->node);
569
570 return 0;
571 }
572 EXPORT_SYMBOL(drm_sched_job_init);
573
574 /**
575 * drm_sched_job_cleanup - clean up scheduler job resources
576 *
577 * @job: scheduler job to clean up
578 */
drm_sched_job_cleanup(struct drm_sched_job * job)579 void drm_sched_job_cleanup(struct drm_sched_job *job)
580 {
581 dma_fence_put(&job->s_fence->finished);
582 job->s_fence = NULL;
583 }
584 EXPORT_SYMBOL(drm_sched_job_cleanup);
585
586 /**
587 * drm_sched_ready - is the scheduler ready
588 *
589 * @sched: scheduler instance
590 *
591 * Return true if we can push more jobs to the hw, otherwise false.
592 */
drm_sched_ready(struct drm_gpu_scheduler * sched)593 static bool drm_sched_ready(struct drm_gpu_scheduler *sched)
594 {
595 return atomic_read(&sched->hw_rq_count) <
596 sched->hw_submission_limit;
597 }
598
599 /**
600 * drm_sched_wakeup - Wake up the scheduler when it is ready
601 *
602 * @sched: scheduler instance
603 *
604 */
drm_sched_wakeup(struct drm_gpu_scheduler * sched)605 void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
606 {
607 if (drm_sched_ready(sched))
608 wake_up_interruptible(&sched->wake_up_worker);
609 }
610
611 /**
612 * drm_sched_select_entity - Select next entity to process
613 *
614 * @sched: scheduler instance
615 *
616 * Returns the entity to process or NULL if none are found.
617 */
618 static struct drm_sched_entity *
drm_sched_select_entity(struct drm_gpu_scheduler * sched)619 drm_sched_select_entity(struct drm_gpu_scheduler *sched)
620 {
621 struct drm_sched_entity *entity;
622 int i;
623
624 if (!drm_sched_ready(sched))
625 return NULL;
626
627 /* Kernel run queue has higher priority than normal run queue*/
628 for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
629 entity = drm_sched_rq_select_entity(&sched->sched_rq[i]);
630 if (entity)
631 break;
632 }
633
634 return entity;
635 }
636
637 /**
638 * drm_sched_process_job - process a job
639 *
640 * @f: fence
641 * @cb: fence callbacks
642 *
643 * Called after job has finished execution.
644 */
drm_sched_process_job(struct dma_fence * f,struct dma_fence_cb * cb)645 static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb)
646 {
647 struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
648 struct drm_sched_fence *s_fence = s_job->s_fence;
649 struct drm_gpu_scheduler *sched = s_fence->sched;
650
651 atomic_dec(&sched->hw_rq_count);
652 atomic_dec(&sched->score);
653
654 trace_drm_sched_process_job(s_fence);
655
656 dma_fence_get(&s_fence->finished);
657 drm_sched_fence_finished(s_fence);
658 dma_fence_put(&s_fence->finished);
659 wake_up_interruptible(&sched->wake_up_worker);
660 }
661
662 /**
663 * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
664 *
665 * @sched: scheduler instance
666 *
667 * Returns the next finished job from the mirror list (if there is one)
668 * ready for it to be destroyed.
669 */
670 static struct drm_sched_job *
drm_sched_get_cleanup_job(struct drm_gpu_scheduler * sched)671 drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
672 {
673 struct drm_sched_job *job;
674
675 /*
676 * Don't destroy jobs while the timeout worker is running OR thread
677 * is being parked and hence assumed to not touch ring_mirror_list
678 */
679 if ((sched->timeout != MAX_SCHEDULE_TIMEOUT &&
680 !cancel_delayed_work(&sched->work_tdr)) ||
681 kthread_should_park())
682 return NULL;
683
684 spin_lock(&sched->job_list_lock);
685
686 job = list_first_entry_or_null(&sched->ring_mirror_list,
687 struct drm_sched_job, node);
688
689 if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
690 /* remove job from ring_mirror_list */
691 list_del_init(&job->node);
692 } else {
693 job = NULL;
694 /* queue timeout for next job */
695 drm_sched_start_timeout(sched);
696 }
697
698 spin_unlock(&sched->job_list_lock);
699
700 return job;
701 }
702
703 /**
704 * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
705 * @sched_list: list of drm_gpu_schedulers
706 * @num_sched_list: number of drm_gpu_schedulers in the sched_list
707 *
708 * Returns pointer of the sched with the least load or NULL if none of the
709 * drm_gpu_schedulers are ready
710 */
711 struct drm_gpu_scheduler *
drm_sched_pick_best(struct drm_gpu_scheduler ** sched_list,unsigned int num_sched_list)712 drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
713 unsigned int num_sched_list)
714 {
715 struct drm_gpu_scheduler *sched, *picked_sched = NULL;
716 int i;
717 unsigned int min_score = UINT_MAX, num_score;
718
719 for (i = 0; i < num_sched_list; ++i) {
720 sched = sched_list[i];
721
722 if (!sched->ready) {
723 DRM_WARN("scheduler %s is not ready, skipping",
724 sched->name);
725 continue;
726 }
727
728 num_score = atomic_read(&sched->score);
729 if (num_score < min_score) {
730 min_score = num_score;
731 picked_sched = sched;
732 }
733 }
734
735 return picked_sched;
736 }
737 EXPORT_SYMBOL(drm_sched_pick_best);
738
739 /**
740 * drm_sched_blocked - check if the scheduler is blocked
741 *
742 * @sched: scheduler instance
743 *
744 * Returns true if blocked, otherwise false.
745 */
drm_sched_blocked(struct drm_gpu_scheduler * sched)746 static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
747 {
748 if (kthread_should_park()) {
749 kthread_parkme();
750 return true;
751 }
752
753 return false;
754 }
755
756 /**
757 * drm_sched_main - main scheduler thread
758 *
759 * @param: scheduler instance
760 *
761 * Returns 0.
762 */
drm_sched_main(void * param)763 static int drm_sched_main(void *param)
764 {
765 struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
766 int r;
767
768 sched_set_fifo_low(current);
769
770 while (!kthread_should_stop()) {
771 struct drm_sched_entity *entity = NULL;
772 struct drm_sched_fence *s_fence;
773 struct drm_sched_job *sched_job;
774 struct dma_fence *fence;
775 struct drm_sched_job *cleanup_job = NULL;
776
777 wait_event_interruptible(sched->wake_up_worker,
778 (cleanup_job = drm_sched_get_cleanup_job(sched)) ||
779 (!drm_sched_blocked(sched) &&
780 (entity = drm_sched_select_entity(sched))) ||
781 kthread_should_stop());
782
783 if (cleanup_job) {
784 sched->ops->free_job(cleanup_job);
785 /* queue timeout for next job */
786 drm_sched_start_timeout(sched);
787 }
788
789 if (!entity)
790 continue;
791
792 sched_job = drm_sched_entity_pop_job(entity);
793
794 complete(&entity->entity_idle);
795
796 if (!sched_job)
797 continue;
798
799 s_fence = sched_job->s_fence;
800
801 atomic_inc(&sched->hw_rq_count);
802 drm_sched_job_begin(sched_job);
803
804 trace_drm_run_job(sched_job, entity);
805 fence = sched->ops->run_job(sched_job);
806 drm_sched_fence_scheduled(s_fence);
807
808 if (!IS_ERR_OR_NULL(fence)) {
809 s_fence->parent = dma_fence_get(fence);
810 r = dma_fence_add_callback(fence, &sched_job->cb,
811 drm_sched_process_job);
812 if (r == -ENOENT)
813 drm_sched_process_job(fence, &sched_job->cb);
814 else if (r)
815 DRM_ERROR("fence add callback failed (%d)\n",
816 r);
817 dma_fence_put(fence);
818 } else {
819 if (IS_ERR(fence))
820 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
821
822 drm_sched_process_job(NULL, &sched_job->cb);
823 }
824
825 wake_up(&sched->job_scheduled);
826 }
827 return 0;
828 }
829
830 /**
831 * drm_sched_init - Init a gpu scheduler instance
832 *
833 * @sched: scheduler instance
834 * @ops: backend operations for this scheduler
835 * @hw_submission: number of hw submissions that can be in flight
836 * @hang_limit: number of times to allow a job to hang before dropping it
837 * @timeout: timeout value in jiffies for the scheduler
838 * @name: name used for debugging
839 *
840 * Return 0 on success, otherwise error code.
841 */
drm_sched_init(struct drm_gpu_scheduler * sched,const struct drm_sched_backend_ops * ops,unsigned hw_submission,unsigned hang_limit,long timeout,const char * name)842 int drm_sched_init(struct drm_gpu_scheduler *sched,
843 const struct drm_sched_backend_ops *ops,
844 unsigned hw_submission,
845 unsigned hang_limit,
846 long timeout,
847 const char *name)
848 {
849 int i, ret;
850 sched->ops = ops;
851 sched->hw_submission_limit = hw_submission;
852 sched->name = name;
853 sched->timeout = timeout;
854 sched->hang_limit = hang_limit;
855 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; i++)
856 drm_sched_rq_init(sched, &sched->sched_rq[i]);
857
858 init_waitqueue_head(&sched->wake_up_worker);
859 init_waitqueue_head(&sched->job_scheduled);
860 INIT_LIST_HEAD(&sched->ring_mirror_list);
861 spin_lock_init(&sched->job_list_lock);
862 atomic_set(&sched->hw_rq_count, 0);
863 INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
864 atomic_set(&sched->score, 0);
865 atomic64_set(&sched->job_id_count, 0);
866
867 /* Each scheduler will run on a seperate kernel thread */
868 sched->thread = kthread_run(drm_sched_main, sched, sched->name);
869 if (IS_ERR(sched->thread)) {
870 ret = PTR_ERR(sched->thread);
871 sched->thread = NULL;
872 DRM_ERROR("Failed to create scheduler for %s.\n", name);
873 return ret;
874 }
875
876 sched->ready = true;
877 return 0;
878 }
879 EXPORT_SYMBOL(drm_sched_init);
880
881 /**
882 * drm_sched_fini - Destroy a gpu scheduler
883 *
884 * @sched: scheduler instance
885 *
886 * Tears down and cleans up the scheduler.
887 */
drm_sched_fini(struct drm_gpu_scheduler * sched)888 void drm_sched_fini(struct drm_gpu_scheduler *sched)
889 {
890 if (sched->thread)
891 kthread_stop(sched->thread);
892
893 sched->ready = false;
894 }
895 EXPORT_SYMBOL(drm_sched_fini);
896
