Loading...
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 * Note that once a job was taken from the entities queue and pushed to the
47 * hardware, i.e. the pending queue, the entity must not be referenced anymore
48 * through the jobs entity pointer.
49 */
50
51/**
52 * DOC: Flow Control
53 *
54 * The DRM GPU scheduler provides a flow control mechanism to regulate the rate
55 * in which the jobs fetched from scheduler entities are executed.
56 *
57 * In this context the &drm_gpu_scheduler keeps track of a driver specified
58 * credit limit representing the capacity of this scheduler and a credit count;
59 * every &drm_sched_job carries a driver specified number of credits.
60 *
61 * Once a job is executed (but not yet finished), the job's credits contribute
62 * to the scheduler's credit count until the job is finished. If by executing
63 * one more job the scheduler's credit count would exceed the scheduler's
64 * credit limit, the job won't be executed. Instead, the scheduler will wait
65 * until the credit count has decreased enough to not overflow its credit limit.
66 * This implies waiting for previously executed jobs.
67 *
68 * Optionally, drivers may register a callback (update_job_credits) provided by
69 * struct drm_sched_backend_ops to update the job's credits dynamically. The
70 * scheduler executes this callback every time the scheduler considers a job for
71 * execution and subsequently checks whether the job fits the scheduler's credit
72 * limit.
73 */
74
75#include <linux/wait.h>
76#include <linux/sched.h>
77#include <linux/completion.h>
78#include <linux/dma-resv.h>
79#include <uapi/linux/sched/types.h>
80
81#include <drm/drm_print.h>
82#include <drm/drm_gem.h>
83#include <drm/drm_syncobj.h>
84#include <drm/gpu_scheduler.h>
85#include <drm/spsc_queue.h>
86
87#define CREATE_TRACE_POINTS
88#include "gpu_scheduler_trace.h"
89
90#define to_drm_sched_job(sched_job) \
91 container_of((sched_job), struct drm_sched_job, queue_node)
92
93int drm_sched_policy = DRM_SCHED_POLICY_FIFO;
94
95/**
96 * DOC: sched_policy (int)
97 * Used to override default entities scheduling policy in a run queue.
98 */
99MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO (default).");
100module_param_named(sched_policy, drm_sched_policy, int, 0444);
101
102static u32 drm_sched_available_credits(struct drm_gpu_scheduler *sched)
103{
104 u32 credits;
105
106 drm_WARN_ON(sched, check_sub_overflow(sched->credit_limit,
107 atomic_read(&sched->credit_count),
108 &credits));
109
110 return credits;
111}
112
113/**
114 * drm_sched_can_queue -- Can we queue more to the hardware?
115 * @sched: scheduler instance
116 * @entity: the scheduler entity
117 *
118 * Return true if we can push at least one more job from @entity, false
119 * otherwise.
120 */
121static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched,
122 struct drm_sched_entity *entity)
123{
124 struct drm_sched_job *s_job;
125
126 s_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
127 if (!s_job)
128 return false;
129
130 if (sched->ops->update_job_credits) {
131 s_job->credits = sched->ops->update_job_credits(s_job);
132
133 drm_WARN(sched, !s_job->credits,
134 "Jobs with zero credits bypass job-flow control.\n");
135 }
136
137 /* If a job exceeds the credit limit, truncate it to the credit limit
138 * itself to guarantee forward progress.
139 */
140 if (drm_WARN(sched, s_job->credits > sched->credit_limit,
141 "Jobs may not exceed the credit limit, truncate.\n"))
142 s_job->credits = sched->credit_limit;
143
144 return drm_sched_available_credits(sched) >= s_job->credits;
145}
146
147static __always_inline bool drm_sched_entity_compare_before(struct rb_node *a,
148 const struct rb_node *b)
149{
150 struct drm_sched_entity *ent_a = rb_entry((a), struct drm_sched_entity, rb_tree_node);
151 struct drm_sched_entity *ent_b = rb_entry((b), struct drm_sched_entity, rb_tree_node);
152
153 return ktime_before(ent_a->oldest_job_waiting, ent_b->oldest_job_waiting);
154}
155
156static inline void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity)
157{
158 struct drm_sched_rq *rq = entity->rq;
159
160 if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
161 rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
162 RB_CLEAR_NODE(&entity->rb_tree_node);
163 }
164}
165
166void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts)
167{
168 /*
169 * Both locks need to be grabbed, one to protect from entity->rq change
170 * for entity from within concurrent drm_sched_entity_select_rq and the
171 * other to update the rb tree structure.
172 */
173 spin_lock(&entity->rq_lock);
174 spin_lock(&entity->rq->lock);
175
176 drm_sched_rq_remove_fifo_locked(entity);
177
178 entity->oldest_job_waiting = ts;
179
180 rb_add_cached(&entity->rb_tree_node, &entity->rq->rb_tree_root,
181 drm_sched_entity_compare_before);
182
183 spin_unlock(&entity->rq->lock);
184 spin_unlock(&entity->rq_lock);
185}
186
187/**
188 * drm_sched_rq_init - initialize a given run queue struct
189 *
190 * @sched: scheduler instance to associate with this run queue
191 * @rq: scheduler run queue
192 *
193 * Initializes a scheduler runqueue.
194 */
195static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
196 struct drm_sched_rq *rq)
197{
198 spin_lock_init(&rq->lock);
199 INIT_LIST_HEAD(&rq->entities);
200 rq->rb_tree_root = RB_ROOT_CACHED;
201 rq->current_entity = NULL;
202 rq->sched = sched;
203}
204
205/**
206 * drm_sched_rq_add_entity - add an entity
207 *
208 * @rq: scheduler run queue
209 * @entity: scheduler entity
210 *
211 * Adds a scheduler entity to the run queue.
212 */
213void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
214 struct drm_sched_entity *entity)
215{
216 if (!list_empty(&entity->list))
217 return;
218
219 spin_lock(&rq->lock);
220
221 atomic_inc(rq->sched->score);
222 list_add_tail(&entity->list, &rq->entities);
223
224 spin_unlock(&rq->lock);
225}
226
227/**
228 * drm_sched_rq_remove_entity - remove an entity
229 *
230 * @rq: scheduler run queue
231 * @entity: scheduler entity
232 *
233 * Removes a scheduler entity from the run queue.
234 */
235void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
236 struct drm_sched_entity *entity)
237{
238 if (list_empty(&entity->list))
239 return;
240
241 spin_lock(&rq->lock);
242
243 atomic_dec(rq->sched->score);
244 list_del_init(&entity->list);
245
246 if (rq->current_entity == entity)
247 rq->current_entity = NULL;
248
249 if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
250 drm_sched_rq_remove_fifo_locked(entity);
251
252 spin_unlock(&rq->lock);
253}
254
255/**
256 * drm_sched_rq_select_entity_rr - Select an entity which could provide a job to run
257 *
258 * @sched: the gpu scheduler
259 * @rq: scheduler run queue to check.
260 *
261 * Try to find the next ready entity.
262 *
263 * Return an entity if one is found; return an error-pointer (!NULL) if an
264 * entity was ready, but the scheduler had insufficient credits to accommodate
265 * its job; return NULL, if no ready entity was found.
266 */
267static struct drm_sched_entity *
268drm_sched_rq_select_entity_rr(struct drm_gpu_scheduler *sched,
269 struct drm_sched_rq *rq)
270{
271 struct drm_sched_entity *entity;
272
273 spin_lock(&rq->lock);
274
275 entity = rq->current_entity;
276 if (entity) {
277 list_for_each_entry_continue(entity, &rq->entities, list) {
278 if (drm_sched_entity_is_ready(entity)) {
279 /* If we can't queue yet, preserve the current
280 * entity in terms of fairness.
281 */
282 if (!drm_sched_can_queue(sched, entity)) {
283 spin_unlock(&rq->lock);
284 return ERR_PTR(-ENOSPC);
285 }
286
287 rq->current_entity = entity;
288 reinit_completion(&entity->entity_idle);
289 spin_unlock(&rq->lock);
290 return entity;
291 }
292 }
293 }
294
295 list_for_each_entry(entity, &rq->entities, list) {
296 if (drm_sched_entity_is_ready(entity)) {
297 /* If we can't queue yet, preserve the current entity in
298 * terms of fairness.
299 */
300 if (!drm_sched_can_queue(sched, entity)) {
301 spin_unlock(&rq->lock);
302 return ERR_PTR(-ENOSPC);
303 }
304
305 rq->current_entity = entity;
306 reinit_completion(&entity->entity_idle);
307 spin_unlock(&rq->lock);
308 return entity;
309 }
310
311 if (entity == rq->current_entity)
312 break;
313 }
314
315 spin_unlock(&rq->lock);
316
317 return NULL;
318}
319
320/**
321 * drm_sched_rq_select_entity_fifo - Select an entity which provides a job to run
322 *
323 * @sched: the gpu scheduler
324 * @rq: scheduler run queue to check.
325 *
326 * Find oldest waiting ready entity.
327 *
328 * Return an entity if one is found; return an error-pointer (!NULL) if an
329 * entity was ready, but the scheduler had insufficient credits to accommodate
330 * its job; return NULL, if no ready entity was found.
331 */
332static struct drm_sched_entity *
333drm_sched_rq_select_entity_fifo(struct drm_gpu_scheduler *sched,
334 struct drm_sched_rq *rq)
335{
336 struct rb_node *rb;
337
338 spin_lock(&rq->lock);
339 for (rb = rb_first_cached(&rq->rb_tree_root); rb; rb = rb_next(rb)) {
340 struct drm_sched_entity *entity;
341
342 entity = rb_entry(rb, struct drm_sched_entity, rb_tree_node);
343 if (drm_sched_entity_is_ready(entity)) {
344 /* If we can't queue yet, preserve the current entity in
345 * terms of fairness.
346 */
347 if (!drm_sched_can_queue(sched, entity)) {
348 spin_unlock(&rq->lock);
349 return ERR_PTR(-ENOSPC);
350 }
351
352 rq->current_entity = entity;
353 reinit_completion(&entity->entity_idle);
354 break;
355 }
356 }
357 spin_unlock(&rq->lock);
358
359 return rb ? rb_entry(rb, struct drm_sched_entity, rb_tree_node) : NULL;
360}
361
362/**
363 * drm_sched_run_job_queue - enqueue run-job work
364 * @sched: scheduler instance
365 */
366static void drm_sched_run_job_queue(struct drm_gpu_scheduler *sched)
367{
368 if (!READ_ONCE(sched->pause_submit))
369 queue_work(sched->submit_wq, &sched->work_run_job);
370}
371
372/**
373 * __drm_sched_run_free_queue - enqueue free-job work
374 * @sched: scheduler instance
375 */
376static void __drm_sched_run_free_queue(struct drm_gpu_scheduler *sched)
377{
378 if (!READ_ONCE(sched->pause_submit))
379 queue_work(sched->submit_wq, &sched->work_free_job);
380}
381
382/**
383 * drm_sched_run_free_queue - enqueue free-job work if ready
384 * @sched: scheduler instance
385 */
386static void drm_sched_run_free_queue(struct drm_gpu_scheduler *sched)
387{
388 struct drm_sched_job *job;
389
390 spin_lock(&sched->job_list_lock);
391 job = list_first_entry_or_null(&sched->pending_list,
392 struct drm_sched_job, list);
393 if (job && dma_fence_is_signaled(&job->s_fence->finished))
394 __drm_sched_run_free_queue(sched);
395 spin_unlock(&sched->job_list_lock);
396}
397
398/**
399 * drm_sched_job_done - complete a job
400 * @s_job: pointer to the job which is done
401 *
402 * Finish the job's fence and wake up the worker thread.
403 */
404static void drm_sched_job_done(struct drm_sched_job *s_job, int result)
405{
406 struct drm_sched_fence *s_fence = s_job->s_fence;
407 struct drm_gpu_scheduler *sched = s_fence->sched;
408
409 atomic_sub(s_job->credits, &sched->credit_count);
410 atomic_dec(sched->score);
411
412 trace_drm_sched_process_job(s_fence);
413
414 dma_fence_get(&s_fence->finished);
415 drm_sched_fence_finished(s_fence, result);
416 dma_fence_put(&s_fence->finished);
417 __drm_sched_run_free_queue(sched);
418}
419
420/**
421 * drm_sched_job_done_cb - the callback for a done job
422 * @f: fence
423 * @cb: fence callbacks
424 */
425static void drm_sched_job_done_cb(struct dma_fence *f, struct dma_fence_cb *cb)
426{
427 struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
428
429 drm_sched_job_done(s_job, f->error);
430}
431
432/**
433 * drm_sched_start_timeout - start timeout for reset worker
434 *
435 * @sched: scheduler instance to start the worker for
436 *
437 * Start the timeout for the given scheduler.
438 */
439static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched)
440{
441 lockdep_assert_held(&sched->job_list_lock);
442
443 if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
444 !list_empty(&sched->pending_list))
445 mod_delayed_work(sched->timeout_wq, &sched->work_tdr, sched->timeout);
446}
447
448static void drm_sched_start_timeout_unlocked(struct drm_gpu_scheduler *sched)
449{
450 spin_lock(&sched->job_list_lock);
451 drm_sched_start_timeout(sched);
452 spin_unlock(&sched->job_list_lock);
453}
454
455/**
456 * drm_sched_tdr_queue_imm: - immediately start job timeout handler
457 *
458 * @sched: scheduler for which the timeout handling should be started.
459 *
460 * Start timeout handling immediately for the named scheduler.
461 */
462void drm_sched_tdr_queue_imm(struct drm_gpu_scheduler *sched)
463{
464 spin_lock(&sched->job_list_lock);
465 sched->timeout = 0;
466 drm_sched_start_timeout(sched);
467 spin_unlock(&sched->job_list_lock);
468}
469EXPORT_SYMBOL(drm_sched_tdr_queue_imm);
470
471/**
472 * drm_sched_fault - immediately start timeout handler
473 *
474 * @sched: scheduler where the timeout handling should be started.
475 *
476 * Start timeout handling immediately when the driver detects a hardware fault.
477 */
478void drm_sched_fault(struct drm_gpu_scheduler *sched)
479{
480 if (sched->timeout_wq)
481 mod_delayed_work(sched->timeout_wq, &sched->work_tdr, 0);
482}
483EXPORT_SYMBOL(drm_sched_fault);
484
485/**
486 * drm_sched_suspend_timeout - Suspend scheduler job timeout
487 *
488 * @sched: scheduler instance for which to suspend the timeout
489 *
490 * Suspend the delayed work timeout for the scheduler. This is done by
491 * modifying the delayed work timeout to an arbitrary large value,
492 * MAX_SCHEDULE_TIMEOUT in this case.
493 *
494 * Returns the timeout remaining
495 *
496 */
497unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched)
498{
499 unsigned long sched_timeout, now = jiffies;
500
501 sched_timeout = sched->work_tdr.timer.expires;
502
503 /*
504 * Modify the timeout to an arbitrarily large value. This also prevents
505 * the timeout to be restarted when new submissions arrive
506 */
507 if (mod_delayed_work(sched->timeout_wq, &sched->work_tdr, MAX_SCHEDULE_TIMEOUT)
508 && time_after(sched_timeout, now))
509 return sched_timeout - now;
510 else
511 return sched->timeout;
512}
513EXPORT_SYMBOL(drm_sched_suspend_timeout);
514
515/**
516 * drm_sched_resume_timeout - Resume scheduler job timeout
517 *
518 * @sched: scheduler instance for which to resume the timeout
519 * @remaining: remaining timeout
520 *
521 * Resume the delayed work timeout for the scheduler.
522 */
523void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
524 unsigned long remaining)
525{
526 spin_lock(&sched->job_list_lock);
527
528 if (list_empty(&sched->pending_list))
529 cancel_delayed_work(&sched->work_tdr);
530 else
531 mod_delayed_work(sched->timeout_wq, &sched->work_tdr, remaining);
532
533 spin_unlock(&sched->job_list_lock);
534}
535EXPORT_SYMBOL(drm_sched_resume_timeout);
536
537static void drm_sched_job_begin(struct drm_sched_job *s_job)
538{
539 struct drm_gpu_scheduler *sched = s_job->sched;
540
541 spin_lock(&sched->job_list_lock);
542 list_add_tail(&s_job->list, &sched->pending_list);
543 drm_sched_start_timeout(sched);
544 spin_unlock(&sched->job_list_lock);
545}
546
547static void drm_sched_job_timedout(struct work_struct *work)
548{
549 struct drm_gpu_scheduler *sched;
550 struct drm_sched_job *job;
551 enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
552
553 sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
554
555 /* Protects against concurrent deletion in drm_sched_get_finished_job */
556 spin_lock(&sched->job_list_lock);
557 job = list_first_entry_or_null(&sched->pending_list,
558 struct drm_sched_job, list);
559
560 if (job) {
561 /*
562 * Remove the bad job so it cannot be freed by concurrent
563 * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
564 * is parked at which point it's safe.
565 */
566 list_del_init(&job->list);
567 spin_unlock(&sched->job_list_lock);
568
569 status = job->sched->ops->timedout_job(job);
570
571 /*
572 * Guilty job did complete and hence needs to be manually removed
573 * See drm_sched_stop doc.
574 */
575 if (sched->free_guilty) {
576 job->sched->ops->free_job(job);
577 sched->free_guilty = false;
578 }
579 } else {
580 spin_unlock(&sched->job_list_lock);
581 }
582
583 if (status != DRM_GPU_SCHED_STAT_ENODEV)
584 drm_sched_start_timeout_unlocked(sched);
585}
586
587/**
588 * drm_sched_stop - stop the scheduler
589 *
590 * @sched: scheduler instance
591 * @bad: job which caused the time out
592 *
593 * Stop the scheduler and also removes and frees all completed jobs.
594 * Note: bad job will not be freed as it might be used later and so it's
595 * callers responsibility to release it manually if it's not part of the
596 * pending list any more.
597 *
598 */
599void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
600{
601 struct drm_sched_job *s_job, *tmp;
602
603 drm_sched_wqueue_stop(sched);
604
605 /*
606 * Reinsert back the bad job here - now it's safe as
607 * drm_sched_get_finished_job cannot race against us and release the
608 * bad job at this point - we parked (waited for) any in progress
609 * (earlier) cleanups and drm_sched_get_finished_job will not be called
610 * now until the scheduler thread is unparked.
611 */
612 if (bad && bad->sched == sched)
613 /*
614 * Add at the head of the queue to reflect it was the earliest
615 * job extracted.
616 */
617 list_add(&bad->list, &sched->pending_list);
618
619 /*
620 * Iterate the job list from later to earlier one and either deactive
621 * their HW callbacks or remove them from pending list if they already
622 * signaled.
623 * This iteration is thread safe as sched thread is stopped.
624 */
625 list_for_each_entry_safe_reverse(s_job, tmp, &sched->pending_list,
626 list) {
627 if (s_job->s_fence->parent &&
628 dma_fence_remove_callback(s_job->s_fence->parent,
629 &s_job->cb)) {
630 dma_fence_put(s_job->s_fence->parent);
631 s_job->s_fence->parent = NULL;
632 atomic_sub(s_job->credits, &sched->credit_count);
633 } else {
634 /*
635 * remove job from pending_list.
636 * Locking here is for concurrent resume timeout
637 */
638 spin_lock(&sched->job_list_lock);
639 list_del_init(&s_job->list);
640 spin_unlock(&sched->job_list_lock);
641
642 /*
643 * Wait for job's HW fence callback to finish using s_job
644 * before releasing it.
645 *
646 * Job is still alive so fence refcount at least 1
647 */
648 dma_fence_wait(&s_job->s_fence->finished, false);
649
650 /*
651 * We must keep bad job alive for later use during
652 * recovery by some of the drivers but leave a hint
653 * that the guilty job must be released.
654 */
655 if (bad != s_job)
656 sched->ops->free_job(s_job);
657 else
658 sched->free_guilty = true;
659 }
660 }
661
662 /*
663 * Stop pending timer in flight as we rearm it in drm_sched_start. This
664 * avoids the pending timeout work in progress to fire right away after
665 * this TDR finished and before the newly restarted jobs had a
666 * chance to complete.
667 */
668 cancel_delayed_work(&sched->work_tdr);
669}
670
671EXPORT_SYMBOL(drm_sched_stop);
672
673/**
674 * drm_sched_start - recover jobs after a reset
675 *
676 * @sched: scheduler instance
677 * @full_recovery: proceed with complete sched restart
678 *
679 */
680void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
681{
682 struct drm_sched_job *s_job, *tmp;
683 int r;
684
685 /*
686 * Locking the list is not required here as the sched thread is parked
687 * so no new jobs are being inserted or removed. Also concurrent
688 * GPU recovers can't run in parallel.
689 */
690 list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
691 struct dma_fence *fence = s_job->s_fence->parent;
692
693 atomic_add(s_job->credits, &sched->credit_count);
694
695 if (!full_recovery)
696 continue;
697
698 if (fence) {
699 r = dma_fence_add_callback(fence, &s_job->cb,
700 drm_sched_job_done_cb);
701 if (r == -ENOENT)
702 drm_sched_job_done(s_job, fence->error);
703 else if (r)
704 DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
705 r);
706 } else
707 drm_sched_job_done(s_job, -ECANCELED);
708 }
709
710 if (full_recovery)
711 drm_sched_start_timeout_unlocked(sched);
712
713 drm_sched_wqueue_start(sched);
714}
715EXPORT_SYMBOL(drm_sched_start);
716
717/**
718 * drm_sched_resubmit_jobs - Deprecated, don't use in new code!
719 *
720 * @sched: scheduler instance
721 *
722 * Re-submitting jobs was a concept AMD came up as cheap way to implement
723 * recovery after a job timeout.
724 *
725 * This turned out to be not working very well. First of all there are many
726 * problem with the dma_fence implementation and requirements. Either the
727 * implementation is risking deadlocks with core memory management or violating
728 * documented implementation details of the dma_fence object.
729 *
730 * Drivers can still save and restore their state for recovery operations, but
731 * we shouldn't make this a general scheduler feature around the dma_fence
732 * interface.
733 */
734void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
735{
736 struct drm_sched_job *s_job, *tmp;
737 uint64_t guilty_context;
738 bool found_guilty = false;
739 struct dma_fence *fence;
740
741 list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
742 struct drm_sched_fence *s_fence = s_job->s_fence;
743
744 if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
745 found_guilty = true;
746 guilty_context = s_job->s_fence->scheduled.context;
747 }
748
749 if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
750 dma_fence_set_error(&s_fence->finished, -ECANCELED);
751
752 fence = sched->ops->run_job(s_job);
753
754 if (IS_ERR_OR_NULL(fence)) {
755 if (IS_ERR(fence))
756 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
757
758 s_job->s_fence->parent = NULL;
759 } else {
760
761 s_job->s_fence->parent = dma_fence_get(fence);
762
763 /* Drop for orignal kref_init */
764 dma_fence_put(fence);
765 }
766 }
767}
768EXPORT_SYMBOL(drm_sched_resubmit_jobs);
769
770/**
771 * drm_sched_job_init - init a scheduler job
772 * @job: scheduler job to init
773 * @entity: scheduler entity to use
774 * @credits: the number of credits this job contributes to the schedulers
775 * credit limit
776 * @owner: job owner for debugging
777 *
778 * Refer to drm_sched_entity_push_job() documentation
779 * for locking considerations.
780 *
781 * Drivers must make sure drm_sched_job_cleanup() if this function returns
782 * successfully, even when @job is aborted before drm_sched_job_arm() is called.
783 *
784 * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
785 * has died, which can mean that there's no valid runqueue for a @entity.
786 * This function returns -ENOENT in this case (which probably should be -EIO as
787 * a more meanigful return value).
788 *
789 * Returns 0 for success, negative error code otherwise.
790 */
791int drm_sched_job_init(struct drm_sched_job *job,
792 struct drm_sched_entity *entity,
793 u32 credits, void *owner)
794{
795 if (!entity->rq) {
796 /* This will most likely be followed by missing frames
797 * or worse--a blank screen--leave a trail in the
798 * logs, so this can be debugged easier.
799 */
800 drm_err(job->sched, "%s: entity has no rq!\n", __func__);
801 return -ENOENT;
802 }
803
804 if (unlikely(!credits)) {
805 pr_err("*ERROR* %s: credits cannot be 0!\n", __func__);
806 return -EINVAL;
807 }
808
809 job->entity = entity;
810 job->credits = credits;
811 job->s_fence = drm_sched_fence_alloc(entity, owner);
812 if (!job->s_fence)
813 return -ENOMEM;
814
815 INIT_LIST_HEAD(&job->list);
816
817 xa_init_flags(&job->dependencies, XA_FLAGS_ALLOC);
818
819 return 0;
820}
821EXPORT_SYMBOL(drm_sched_job_init);
822
823/**
824 * drm_sched_job_arm - arm a scheduler job for execution
825 * @job: scheduler job to arm
826 *
827 * This arms a scheduler job for execution. Specifically it initializes the
828 * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
829 * or other places that need to track the completion of this job.
830 *
831 * Refer to drm_sched_entity_push_job() documentation for locking
832 * considerations.
833 *
834 * This can only be called if drm_sched_job_init() succeeded.
835 */
836void drm_sched_job_arm(struct drm_sched_job *job)
837{
838 struct drm_gpu_scheduler *sched;
839 struct drm_sched_entity *entity = job->entity;
840
841 BUG_ON(!entity);
842 drm_sched_entity_select_rq(entity);
843 sched = entity->rq->sched;
844
845 job->sched = sched;
846 job->s_priority = entity->priority;
847 job->id = atomic64_inc_return(&sched->job_id_count);
848
849 drm_sched_fence_init(job->s_fence, job->entity);
850}
851EXPORT_SYMBOL(drm_sched_job_arm);
852
853/**
854 * drm_sched_job_add_dependency - adds the fence as a job dependency
855 * @job: scheduler job to add the dependencies to
856 * @fence: the dma_fence to add to the list of dependencies.
857 *
858 * Note that @fence is consumed in both the success and error cases.
859 *
860 * Returns:
861 * 0 on success, or an error on failing to expand the array.
862 */
863int drm_sched_job_add_dependency(struct drm_sched_job *job,
864 struct dma_fence *fence)
865{
866 struct dma_fence *entry;
867 unsigned long index;
868 u32 id = 0;
869 int ret;
870
871 if (!fence)
872 return 0;
873
874 /* Deduplicate if we already depend on a fence from the same context.
875 * This lets the size of the array of deps scale with the number of
876 * engines involved, rather than the number of BOs.
877 */
878 xa_for_each(&job->dependencies, index, entry) {
879 if (entry->context != fence->context)
880 continue;
881
882 if (dma_fence_is_later(fence, entry)) {
883 dma_fence_put(entry);
884 xa_store(&job->dependencies, index, fence, GFP_KERNEL);
885 } else {
886 dma_fence_put(fence);
887 }
888 return 0;
889 }
890
891 ret = xa_alloc(&job->dependencies, &id, fence, xa_limit_32b, GFP_KERNEL);
892 if (ret != 0)
893 dma_fence_put(fence);
894
895 return ret;
896}
897EXPORT_SYMBOL(drm_sched_job_add_dependency);
898
899/**
900 * drm_sched_job_add_syncobj_dependency - adds a syncobj's fence as a job dependency
901 * @job: scheduler job to add the dependencies to
902 * @file: drm file private pointer
903 * @handle: syncobj handle to lookup
904 * @point: timeline point
905 *
906 * This adds the fence matching the given syncobj to @job.
907 *
908 * Returns:
909 * 0 on success, or an error on failing to expand the array.
910 */
911int drm_sched_job_add_syncobj_dependency(struct drm_sched_job *job,
912 struct drm_file *file,
913 u32 handle,
914 u32 point)
915{
916 struct dma_fence *fence;
917 int ret;
918
919 ret = drm_syncobj_find_fence(file, handle, point, 0, &fence);
920 if (ret)
921 return ret;
922
923 return drm_sched_job_add_dependency(job, fence);
924}
925EXPORT_SYMBOL(drm_sched_job_add_syncobj_dependency);
926
927/**
928 * drm_sched_job_add_resv_dependencies - add all fences from the resv to the job
929 * @job: scheduler job to add the dependencies to
930 * @resv: the dma_resv object to get the fences from
931 * @usage: the dma_resv_usage to use to filter the fences
932 *
933 * This adds all fences matching the given usage from @resv to @job.
934 * Must be called with the @resv lock held.
935 *
936 * Returns:
937 * 0 on success, or an error on failing to expand the array.
938 */
939int drm_sched_job_add_resv_dependencies(struct drm_sched_job *job,
940 struct dma_resv *resv,
941 enum dma_resv_usage usage)
942{
943 struct dma_resv_iter cursor;
944 struct dma_fence *fence;
945 int ret;
946
947 dma_resv_assert_held(resv);
948
949 dma_resv_for_each_fence(&cursor, resv, usage, fence) {
950 /* Make sure to grab an additional ref on the added fence */
951 dma_fence_get(fence);
952 ret = drm_sched_job_add_dependency(job, fence);
953 if (ret) {
954 dma_fence_put(fence);
955 return ret;
956 }
957 }
958 return 0;
959}
960EXPORT_SYMBOL(drm_sched_job_add_resv_dependencies);
961
962/**
963 * drm_sched_job_add_implicit_dependencies - adds implicit dependencies as job
964 * dependencies
965 * @job: scheduler job to add the dependencies to
966 * @obj: the gem object to add new dependencies from.
967 * @write: whether the job might write the object (so we need to depend on
968 * shared fences in the reservation object).
969 *
970 * This should be called after drm_gem_lock_reservations() on your array of
971 * GEM objects used in the job but before updating the reservations with your
972 * own fences.
973 *
974 * Returns:
975 * 0 on success, or an error on failing to expand the array.
976 */
977int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
978 struct drm_gem_object *obj,
979 bool write)
980{
981 return drm_sched_job_add_resv_dependencies(job, obj->resv,
982 dma_resv_usage_rw(write));
983}
984EXPORT_SYMBOL(drm_sched_job_add_implicit_dependencies);
985
986/**
987 * drm_sched_job_cleanup - clean up scheduler job resources
988 * @job: scheduler job to clean up
989 *
990 * Cleans up the resources allocated with drm_sched_job_init().
991 *
992 * Drivers should call this from their error unwind code if @job is aborted
993 * before drm_sched_job_arm() is called.
994 *
995 * After that point of no return @job is committed to be executed by the
996 * scheduler, and this function should be called from the
997 * &drm_sched_backend_ops.free_job callback.
998 */
999void drm_sched_job_cleanup(struct drm_sched_job *job)
1000{
1001 struct dma_fence *fence;
1002 unsigned long index;
1003
1004 if (kref_read(&job->s_fence->finished.refcount)) {
1005 /* drm_sched_job_arm() has been called */
1006 dma_fence_put(&job->s_fence->finished);
1007 } else {
1008 /* aborted job before committing to run it */
1009 drm_sched_fence_free(job->s_fence);
1010 }
1011
1012 job->s_fence = NULL;
1013
1014 xa_for_each(&job->dependencies, index, fence) {
1015 dma_fence_put(fence);
1016 }
1017 xa_destroy(&job->dependencies);
1018
1019}
1020EXPORT_SYMBOL(drm_sched_job_cleanup);
1021
1022/**
1023 * drm_sched_wakeup - Wake up the scheduler if it is ready to queue
1024 * @sched: scheduler instance
1025 * @entity: the scheduler entity
1026 *
1027 * Wake up the scheduler if we can queue jobs.
1028 */
1029void drm_sched_wakeup(struct drm_gpu_scheduler *sched,
1030 struct drm_sched_entity *entity)
1031{
1032 if (drm_sched_can_queue(sched, entity))
1033 drm_sched_run_job_queue(sched);
1034}
1035
1036/**
1037 * drm_sched_select_entity - Select next entity to process
1038 *
1039 * @sched: scheduler instance
1040 *
1041 * Return an entity to process or NULL if none are found.
1042 *
1043 * Note, that we break out of the for-loop when "entity" is non-null, which can
1044 * also be an error-pointer--this assures we don't process lower priority
1045 * run-queues. See comments in the respectively called functions.
1046 */
1047static struct drm_sched_entity *
1048drm_sched_select_entity(struct drm_gpu_scheduler *sched)
1049{
1050 struct drm_sched_entity *entity;
1051 int i;
1052
1053 /* Start with the highest priority.
1054 */
1055 for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
1056 entity = drm_sched_policy == DRM_SCHED_POLICY_FIFO ?
1057 drm_sched_rq_select_entity_fifo(sched, sched->sched_rq[i]) :
1058 drm_sched_rq_select_entity_rr(sched, sched->sched_rq[i]);
1059 if (entity)
1060 break;
1061 }
1062
1063 return IS_ERR(entity) ? NULL : entity;
1064}
1065
1066/**
1067 * drm_sched_get_finished_job - fetch the next finished job to be destroyed
1068 *
1069 * @sched: scheduler instance
1070 *
1071 * Returns the next finished job from the pending list (if there is one)
1072 * ready for it to be destroyed.
1073 */
1074static struct drm_sched_job *
1075drm_sched_get_finished_job(struct drm_gpu_scheduler *sched)
1076{
1077 struct drm_sched_job *job, *next;
1078
1079 spin_lock(&sched->job_list_lock);
1080
1081 job = list_first_entry_or_null(&sched->pending_list,
1082 struct drm_sched_job, list);
1083
1084 if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
1085 /* remove job from pending_list */
1086 list_del_init(&job->list);
1087
1088 /* cancel this job's TO timer */
1089 cancel_delayed_work(&sched->work_tdr);
1090 /* make the scheduled timestamp more accurate */
1091 next = list_first_entry_or_null(&sched->pending_list,
1092 typeof(*next), list);
1093
1094 if (next) {
1095 if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT,
1096 &next->s_fence->scheduled.flags))
1097 next->s_fence->scheduled.timestamp =
1098 dma_fence_timestamp(&job->s_fence->finished);
1099 /* start TO timer for next job */
1100 drm_sched_start_timeout(sched);
1101 }
1102 } else {
1103 job = NULL;
1104 }
1105
1106 spin_unlock(&sched->job_list_lock);
1107
1108 return job;
1109}
1110
1111/**
1112 * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
1113 * @sched_list: list of drm_gpu_schedulers
1114 * @num_sched_list: number of drm_gpu_schedulers in the sched_list
1115 *
1116 * Returns pointer of the sched with the least load or NULL if none of the
1117 * drm_gpu_schedulers are ready
1118 */
1119struct drm_gpu_scheduler *
1120drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
1121 unsigned int num_sched_list)
1122{
1123 struct drm_gpu_scheduler *sched, *picked_sched = NULL;
1124 int i;
1125 unsigned int min_score = UINT_MAX, num_score;
1126
1127 for (i = 0; i < num_sched_list; ++i) {
1128 sched = sched_list[i];
1129
1130 if (!sched->ready) {
1131 DRM_WARN("scheduler %s is not ready, skipping",
1132 sched->name);
1133 continue;
1134 }
1135
1136 num_score = atomic_read(sched->score);
1137 if (num_score < min_score) {
1138 min_score = num_score;
1139 picked_sched = sched;
1140 }
1141 }
1142
1143 return picked_sched;
1144}
1145EXPORT_SYMBOL(drm_sched_pick_best);
1146
1147/**
1148 * drm_sched_free_job_work - worker to call free_job
1149 *
1150 * @w: free job work
1151 */
1152static void drm_sched_free_job_work(struct work_struct *w)
1153{
1154 struct drm_gpu_scheduler *sched =
1155 container_of(w, struct drm_gpu_scheduler, work_free_job);
1156 struct drm_sched_job *job;
1157
1158 if (READ_ONCE(sched->pause_submit))
1159 return;
1160
1161 job = drm_sched_get_finished_job(sched);
1162 if (job)
1163 sched->ops->free_job(job);
1164
1165 drm_sched_run_free_queue(sched);
1166 drm_sched_run_job_queue(sched);
1167}
1168
1169/**
1170 * drm_sched_run_job_work - worker to call run_job
1171 *
1172 * @w: run job work
1173 */
1174static void drm_sched_run_job_work(struct work_struct *w)
1175{
1176 struct drm_gpu_scheduler *sched =
1177 container_of(w, struct drm_gpu_scheduler, work_run_job);
1178 struct drm_sched_entity *entity;
1179 struct dma_fence *fence;
1180 struct drm_sched_fence *s_fence;
1181 struct drm_sched_job *sched_job;
1182 int r;
1183
1184 if (READ_ONCE(sched->pause_submit))
1185 return;
1186
1187 /* Find entity with a ready job */
1188 entity = drm_sched_select_entity(sched);
1189 if (!entity)
1190 return; /* No more work */
1191
1192 sched_job = drm_sched_entity_pop_job(entity);
1193 if (!sched_job) {
1194 complete_all(&entity->entity_idle);
1195 drm_sched_run_job_queue(sched);
1196 return;
1197 }
1198
1199 s_fence = sched_job->s_fence;
1200
1201 atomic_add(sched_job->credits, &sched->credit_count);
1202 drm_sched_job_begin(sched_job);
1203
1204 trace_drm_run_job(sched_job, entity);
1205 fence = sched->ops->run_job(sched_job);
1206 complete_all(&entity->entity_idle);
1207 drm_sched_fence_scheduled(s_fence, fence);
1208
1209 if (!IS_ERR_OR_NULL(fence)) {
1210 /* Drop for original kref_init of the fence */
1211 dma_fence_put(fence);
1212
1213 r = dma_fence_add_callback(fence, &sched_job->cb,
1214 drm_sched_job_done_cb);
1215 if (r == -ENOENT)
1216 drm_sched_job_done(sched_job, fence->error);
1217 else if (r)
1218 DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n", r);
1219 } else {
1220 drm_sched_job_done(sched_job, IS_ERR(fence) ?
1221 PTR_ERR(fence) : 0);
1222 }
1223
1224 wake_up(&sched->job_scheduled);
1225 drm_sched_run_job_queue(sched);
1226}
1227
1228/**
1229 * drm_sched_init - Init a gpu scheduler instance
1230 *
1231 * @sched: scheduler instance
1232 * @ops: backend operations for this scheduler
1233 * @submit_wq: workqueue to use for submission. If NULL, an ordered wq is
1234 * allocated and used
1235 * @num_rqs: number of runqueues, one for each priority, up to DRM_SCHED_PRIORITY_COUNT
1236 * @credit_limit: the number of credits this scheduler can hold from all jobs
1237 * @hang_limit: number of times to allow a job to hang before dropping it
1238 * @timeout: timeout value in jiffies for the scheduler
1239 * @timeout_wq: workqueue to use for timeout work. If NULL, the system_wq is
1240 * used
1241 * @score: optional score atomic shared with other schedulers
1242 * @name: name used for debugging
1243 * @dev: target &struct device
1244 *
1245 * Return 0 on success, otherwise error code.
1246 */
1247int drm_sched_init(struct drm_gpu_scheduler *sched,
1248 const struct drm_sched_backend_ops *ops,
1249 struct workqueue_struct *submit_wq,
1250 u32 num_rqs, u32 credit_limit, unsigned int hang_limit,
1251 long timeout, struct workqueue_struct *timeout_wq,
1252 atomic_t *score, const char *name, struct device *dev)
1253{
1254 int i, ret;
1255
1256 sched->ops = ops;
1257 sched->credit_limit = credit_limit;
1258 sched->name = name;
1259 sched->timeout = timeout;
1260 sched->timeout_wq = timeout_wq ? : system_wq;
1261 sched->hang_limit = hang_limit;
1262 sched->score = score ? score : &sched->_score;
1263 sched->dev = dev;
1264
1265 if (num_rqs > DRM_SCHED_PRIORITY_COUNT) {
1266 /* This is a gross violation--tell drivers what the problem is.
1267 */
1268 drm_err(sched, "%s: num_rqs cannot be greater than DRM_SCHED_PRIORITY_COUNT\n",
1269 __func__);
1270 return -EINVAL;
1271 } else if (sched->sched_rq) {
1272 /* Not an error, but warn anyway so drivers can
1273 * fine-tune their DRM calling order, and return all
1274 * is good.
1275 */
1276 drm_warn(sched, "%s: scheduler already initialized!\n", __func__);
1277 return 0;
1278 }
1279
1280 if (submit_wq) {
1281 sched->submit_wq = submit_wq;
1282 sched->own_submit_wq = false;
1283 } else {
1284 sched->submit_wq = alloc_ordered_workqueue(name, 0);
1285 if (!sched->submit_wq)
1286 return -ENOMEM;
1287
1288 sched->own_submit_wq = true;
1289 }
1290 ret = -ENOMEM;
1291 sched->sched_rq = kmalloc_array(num_rqs, sizeof(*sched->sched_rq),
1292 GFP_KERNEL | __GFP_ZERO);
1293 if (!sched->sched_rq)
1294 goto Out_free;
1295 sched->num_rqs = num_rqs;
1296 for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
1297 sched->sched_rq[i] = kzalloc(sizeof(*sched->sched_rq[i]), GFP_KERNEL);
1298 if (!sched->sched_rq[i])
1299 goto Out_unroll;
1300 drm_sched_rq_init(sched, sched->sched_rq[i]);
1301 }
1302
1303 init_waitqueue_head(&sched->job_scheduled);
1304 INIT_LIST_HEAD(&sched->pending_list);
1305 spin_lock_init(&sched->job_list_lock);
1306 atomic_set(&sched->credit_count, 0);
1307 INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
1308 INIT_WORK(&sched->work_run_job, drm_sched_run_job_work);
1309 INIT_WORK(&sched->work_free_job, drm_sched_free_job_work);
1310 atomic_set(&sched->_score, 0);
1311 atomic64_set(&sched->job_id_count, 0);
1312 sched->pause_submit = false;
1313
1314 sched->ready = true;
1315 return 0;
1316Out_unroll:
1317 for (--i ; i >= DRM_SCHED_PRIORITY_KERNEL; i--)
1318 kfree(sched->sched_rq[i]);
1319Out_free:
1320 kfree(sched->sched_rq);
1321 sched->sched_rq = NULL;
1322 if (sched->own_submit_wq)
1323 destroy_workqueue(sched->submit_wq);
1324 drm_err(sched, "%s: Failed to setup GPU scheduler--out of memory\n", __func__);
1325 return ret;
1326}
1327EXPORT_SYMBOL(drm_sched_init);
1328
1329/**
1330 * drm_sched_fini - Destroy a gpu scheduler
1331 *
1332 * @sched: scheduler instance
1333 *
1334 * Tears down and cleans up the scheduler.
1335 */
1336void drm_sched_fini(struct drm_gpu_scheduler *sched)
1337{
1338 struct drm_sched_entity *s_entity;
1339 int i;
1340
1341 drm_sched_wqueue_stop(sched);
1342
1343 for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) {
1344 struct drm_sched_rq *rq = sched->sched_rq[i];
1345
1346 spin_lock(&rq->lock);
1347 list_for_each_entry(s_entity, &rq->entities, list)
1348 /*
1349 * Prevents reinsertion and marks job_queue as idle,
1350 * it will removed from rq in drm_sched_entity_fini
1351 * eventually
1352 */
1353 s_entity->stopped = true;
1354 spin_unlock(&rq->lock);
1355 kfree(sched->sched_rq[i]);
1356 }
1357
1358 /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
1359 wake_up_all(&sched->job_scheduled);
1360
1361 /* Confirm no work left behind accessing device structures */
1362 cancel_delayed_work_sync(&sched->work_tdr);
1363
1364 if (sched->own_submit_wq)
1365 destroy_workqueue(sched->submit_wq);
1366 sched->ready = false;
1367 kfree(sched->sched_rq);
1368 sched->sched_rq = NULL;
1369}
1370EXPORT_SYMBOL(drm_sched_fini);
1371
1372/**
1373 * drm_sched_increase_karma - Update sched_entity guilty flag
1374 *
1375 * @bad: The job guilty of time out
1376 *
1377 * Increment on every hang caused by the 'bad' job. If this exceeds the hang
1378 * limit of the scheduler then the respective sched entity is marked guilty and
1379 * jobs from it will not be scheduled further
1380 */
1381void drm_sched_increase_karma(struct drm_sched_job *bad)
1382{
1383 int i;
1384 struct drm_sched_entity *tmp;
1385 struct drm_sched_entity *entity;
1386 struct drm_gpu_scheduler *sched = bad->sched;
1387
1388 /* don't change @bad's karma if it's from KERNEL RQ,
1389 * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
1390 * corrupt but keep in mind that kernel jobs always considered good.
1391 */
1392 if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
1393 atomic_inc(&bad->karma);
1394
1395 for (i = DRM_SCHED_PRIORITY_HIGH; i < sched->num_rqs; i++) {
1396 struct drm_sched_rq *rq = sched->sched_rq[i];
1397
1398 spin_lock(&rq->lock);
1399 list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
1400 if (bad->s_fence->scheduled.context ==
1401 entity->fence_context) {
1402 if (entity->guilty)
1403 atomic_set(entity->guilty, 1);
1404 break;
1405 }
1406 }
1407 spin_unlock(&rq->lock);
1408 if (&entity->list != &rq->entities)
1409 break;
1410 }
1411 }
1412}
1413EXPORT_SYMBOL(drm_sched_increase_karma);
1414
1415/**
1416 * drm_sched_wqueue_ready - Is the scheduler ready for submission
1417 *
1418 * @sched: scheduler instance
1419 *
1420 * Returns true if submission is ready
1421 */
1422bool drm_sched_wqueue_ready(struct drm_gpu_scheduler *sched)
1423{
1424 return sched->ready;
1425}
1426EXPORT_SYMBOL(drm_sched_wqueue_ready);
1427
1428/**
1429 * drm_sched_wqueue_stop - stop scheduler submission
1430 *
1431 * @sched: scheduler instance
1432 */
1433void drm_sched_wqueue_stop(struct drm_gpu_scheduler *sched)
1434{
1435 WRITE_ONCE(sched->pause_submit, true);
1436 cancel_work_sync(&sched->work_run_job);
1437 cancel_work_sync(&sched->work_free_job);
1438}
1439EXPORT_SYMBOL(drm_sched_wqueue_stop);
1440
1441/**
1442 * drm_sched_wqueue_start - start scheduler submission
1443 *
1444 * @sched: scheduler instance
1445 */
1446void drm_sched_wqueue_start(struct drm_gpu_scheduler *sched)
1447{
1448 WRITE_ONCE(sched->pause_submit, false);
1449 queue_work(sched->submit_wq, &sched->work_run_job);
1450 queue_work(sched->submit_wq, &sched->work_free_job);
1451}
1452EXPORT_SYMBOL(drm_sched_wqueue_start);
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
63static 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 */
72static 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 */
89void 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 */
108void 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 */
128static struct drm_sched_entity *
129drm_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 */
173bool 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}
189EXPORT_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 */
198static 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 */
212void drm_sched_fault(struct drm_gpu_scheduler *sched)
213{
214 mod_delayed_work(system_wq, &sched->work_tdr, 0);
215}
216EXPORT_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 */
230unsigned 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}
246EXPORT_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 */
256void 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}
268EXPORT_SYMBOL(drm_sched_resume_timeout);
269
270static 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
280static 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 */
329void 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}
363EXPORT_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 */
377void 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
446EXPORT_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 */
455void 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}
493EXPORT_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 */
501void 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}
534EXPORT_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 */
548int 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}
572EXPORT_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 */
579void drm_sched_job_cleanup(struct drm_sched_job *job)
580{
581 dma_fence_put(&job->s_fence->finished);
582 job->s_fence = NULL;
583}
584EXPORT_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 */
593static 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 */
605void 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 */
618static struct drm_sched_entity *
619drm_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_MAX - 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 */
645static 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 */
670static struct drm_sched_job *
671drm_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 */
711struct drm_gpu_scheduler *
712drm_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}
737EXPORT_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 */
746static 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 */
763static 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 */
842int 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_MAX; 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}
879EXPORT_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 */
888void drm_sched_fini(struct drm_gpu_scheduler *sched)
889{
890 if (sched->thread)
891 kthread_stop(sched->thread);
892
893 sched->ready = false;
894}
895EXPORT_SYMBOL(drm_sched_fini);