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 #include <linux/kthread.h>
25 #include <linux/slab.h>
26 #include <linux/completion.h>
27 
28 #include <drm/drm_print.h>
29 #include <drm/gpu_scheduler.h>
30 
31 #include "gpu_scheduler_trace.h"
32 
33 #define to_drm_sched_job(sched_job)		\
34 		container_of((sched_job), struct drm_sched_job, queue_node)
35 
36 /**
37  * drm_sched_entity_init - Init a context entity used by scheduler when
38  * submit to HW ring.
39  *
40  * @entity: scheduler entity to init
41  * @priority: priority of the entity
42  * @sched_list: the list of drm scheds on which jobs from this
43  *           entity can be submitted
44  * @num_sched_list: number of drm sched in sched_list
45  * @guilty: atomic_t set to 1 when a job on this queue
46  *          is found to be guilty causing a timeout
47  *
48  * Note: the sched_list should have at least one element to schedule
49  *       the entity
50  *
51  * Returns 0 on success or a negative error code on failure.
52  */
53 int drm_sched_entity_init(struct drm_sched_entity *entity,
54 			  enum drm_sched_priority priority,
55 			  struct drm_gpu_scheduler **sched_list,
56 			  unsigned int num_sched_list,
57 			  atomic_t *guilty)
58 {
59 	if (!(entity && sched_list && (num_sched_list == 0 || sched_list[0])))
60 		return -EINVAL;
61 
62 	memset(entity, 0, sizeof(struct drm_sched_entity));
63 	INIT_LIST_HEAD(&entity->list);
64 	entity->rq = NULL;
65 	entity->guilty = guilty;
66 	entity->num_sched_list = num_sched_list;
67 	entity->priority = priority;
68 	entity->sched_list = num_sched_list > 1 ? sched_list : NULL;
69 	entity->last_scheduled = NULL;
70 
71 	if(num_sched_list)
72 		entity->rq = &sched_list[0]->sched_rq[entity->priority];
73 
74 	init_completion(&entity->entity_idle);
75 
76 	/* We start in an idle state. */
77 	complete(&entity->entity_idle);
78 
79 	spin_lock_init(&entity->rq_lock);
80 	spsc_queue_init(&entity->job_queue);
81 
82 	atomic_set(&entity->fence_seq, 0);
83 	entity->fence_context = dma_fence_context_alloc(2);
84 
85 	return 0;
86 }
87 EXPORT_SYMBOL(drm_sched_entity_init);
88 
89 /**
90  * drm_sched_entity_modify_sched - Modify sched of an entity
91  * @entity: scheduler entity to init
92  * @sched_list: the list of new drm scheds which will replace
93  *		 existing entity->sched_list
94  * @num_sched_list: number of drm sched in sched_list
95  */
96 void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
97 				    struct drm_gpu_scheduler **sched_list,
98 				    unsigned int num_sched_list)
99 {
100 	WARN_ON(!num_sched_list || !sched_list);
101 
102 	entity->sched_list = sched_list;
103 	entity->num_sched_list = num_sched_list;
104 }
105 EXPORT_SYMBOL(drm_sched_entity_modify_sched);
106 
107 /**
108  * drm_sched_entity_is_idle - Check if entity is idle
109  *
110  * @entity: scheduler entity
111  *
112  * Returns true if the entity does not have any unscheduled jobs.
113  */
114 static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity)
115 {
116 	rmb(); /* for list_empty to work without lock */
117 
118 	if (list_empty(&entity->list) ||
119 	    spsc_queue_count(&entity->job_queue) == 0)
120 		return true;
121 
122 	return false;
123 }
124 
125 /**
126  * drm_sched_entity_is_ready - Check if entity is ready
127  *
128  * @entity: scheduler entity
129  *
130  * Return true if entity could provide a job.
131  */
132 bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
133 {
134 	if (spsc_queue_peek(&entity->job_queue) == NULL)
135 		return false;
136 
137 	if (READ_ONCE(entity->dependency))
138 		return false;
139 
140 	return true;
141 }
142 
143 /**
144  * drm_sched_entity_flush - Flush a context entity
145  *
146  * @entity: scheduler entity
147  * @timeout: time to wait in for Q to become empty in jiffies.
148  *
149  * Splitting drm_sched_entity_fini() into two functions, The first one does the
150  * waiting, removes the entity from the runqueue and returns an error when the
151  * process was killed.
152  *
153  * Returns the remaining time in jiffies left from the input timeout
154  */
155 long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
156 {
157 	struct drm_gpu_scheduler *sched;
158 	struct task_struct *last_user;
159 	long ret = timeout;
160 
161 	if (!entity->rq)
162 		return 0;
163 
164 	sched = entity->rq->sched;
165 	/**
166 	 * The client will not queue more IBs during this fini, consume existing
167 	 * queued IBs or discard them on SIGKILL
168 	 */
169 	if (current->flags & PF_EXITING) {
170 		if (timeout)
171 			ret = wait_event_timeout(
172 					sched->job_scheduled,
173 					drm_sched_entity_is_idle(entity),
174 					timeout);
175 	} else {
176 		wait_event_killable(sched->job_scheduled,
177 				    drm_sched_entity_is_idle(entity));
178 	}
179 
180 	/* For killed process disable any more IBs enqueue right now */
181 	last_user = cmpxchg(&entity->last_user, current->group_leader, NULL);
182 	if ((!last_user || last_user == current->group_leader) &&
183 	    (current->flags & PF_EXITING) && (current->exit_code == SIGKILL)) {
184 		spin_lock(&entity->rq_lock);
185 		entity->stopped = true;
186 		drm_sched_rq_remove_entity(entity->rq, entity);
187 		spin_unlock(&entity->rq_lock);
188 	}
189 
190 	return ret;
191 }
192 EXPORT_SYMBOL(drm_sched_entity_flush);
193 
194 /**
195  * drm_sched_entity_kill_jobs - helper for drm_sched_entity_kill_jobs
196  *
197  * @f: signaled fence
198  * @cb: our callback structure
199  *
200  * Signal the scheduler finished fence when the entity in question is killed.
201  */
202 static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
203 					  struct dma_fence_cb *cb)
204 {
205 	struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
206 						 finish_cb);
207 
208 	drm_sched_fence_finished(job->s_fence);
209 	WARN_ON(job->s_fence->parent);
210 	job->sched->ops->free_job(job);
211 }
212 
213 /**
214  * drm_sched_entity_kill_jobs - Make sure all remaining jobs are killed
215  *
216  * @entity: entity which is cleaned up
217  *
218  * Makes sure that all remaining jobs in an entity are killed before it is
219  * destroyed.
220  */
221 static void drm_sched_entity_kill_jobs(struct drm_sched_entity *entity)
222 {
223 	struct drm_sched_job *job;
224 	int r;
225 
226 	while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {
227 		struct drm_sched_fence *s_fence = job->s_fence;
228 
229 		drm_sched_fence_scheduled(s_fence);
230 		dma_fence_set_error(&s_fence->finished, -ESRCH);
231 
232 		/*
233 		 * When pipe is hanged by older entity, new entity might
234 		 * not even have chance to submit it's first job to HW
235 		 * and so entity->last_scheduled will remain NULL
236 		 */
237 		if (!entity->last_scheduled) {
238 			drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
239 			continue;
240 		}
241 
242 		r = dma_fence_add_callback(entity->last_scheduled,
243 					   &job->finish_cb,
244 					   drm_sched_entity_kill_jobs_cb);
245 		if (r == -ENOENT)
246 			drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
247 		else if (r)
248 			DRM_ERROR("fence add callback failed (%d)\n", r);
249 	}
250 }
251 
252 /**
253  * drm_sched_entity_cleanup - Destroy a context entity
254  *
255  * @entity: scheduler entity
256  *
257  * This should be called after @drm_sched_entity_do_release. It goes over the
258  * entity and signals all jobs with an error code if the process was killed.
259  *
260  */
261 void drm_sched_entity_fini(struct drm_sched_entity *entity)
262 {
263 	struct drm_gpu_scheduler *sched = NULL;
264 
265 	if (entity->rq) {
266 		sched = entity->rq->sched;
267 		drm_sched_rq_remove_entity(entity->rq, entity);
268 	}
269 
270 	/* Consumption of existing IBs wasn't completed. Forcefully
271 	 * remove them here.
272 	 */
273 	if (spsc_queue_count(&entity->job_queue)) {
274 		if (sched) {
275 			/*
276 			 * Wait for thread to idle to make sure it isn't processing
277 			 * this entity.
278 			 */
279 			wait_for_completion(&entity->entity_idle);
280 
281 		}
282 		if (entity->dependency) {
283 			dma_fence_remove_callback(entity->dependency,
284 						  &entity->cb);
285 			dma_fence_put(entity->dependency);
286 			entity->dependency = NULL;
287 		}
288 
289 		drm_sched_entity_kill_jobs(entity);
290 	}
291 
292 	dma_fence_put(entity->last_scheduled);
293 	entity->last_scheduled = NULL;
294 }
295 EXPORT_SYMBOL(drm_sched_entity_fini);
296 
297 /**
298  * drm_sched_entity_fini - Destroy a context entity
299  *
300  * @entity: scheduler entity
301  *
302  * Calls drm_sched_entity_do_release() and drm_sched_entity_cleanup()
303  */
304 void drm_sched_entity_destroy(struct drm_sched_entity *entity)
305 {
306 	drm_sched_entity_flush(entity, MAX_WAIT_SCHED_ENTITY_Q_EMPTY);
307 	drm_sched_entity_fini(entity);
308 }
309 EXPORT_SYMBOL(drm_sched_entity_destroy);
310 
311 /*
312  * drm_sched_entity_clear_dep - callback to clear the entities dependency
313  */
314 static void drm_sched_entity_clear_dep(struct dma_fence *f,
315 				       struct dma_fence_cb *cb)
316 {
317 	struct drm_sched_entity *entity =
318 		container_of(cb, struct drm_sched_entity, cb);
319 
320 	entity->dependency = NULL;
321 	dma_fence_put(f);
322 }
323 
324 /*
325  * drm_sched_entity_clear_dep - callback to clear the entities dependency and
326  * wake up scheduler
327  */
328 static void drm_sched_entity_wakeup(struct dma_fence *f,
329 				    struct dma_fence_cb *cb)
330 {
331 	struct drm_sched_entity *entity =
332 		container_of(cb, struct drm_sched_entity, cb);
333 
334 	drm_sched_entity_clear_dep(f, cb);
335 	drm_sched_wakeup(entity->rq->sched);
336 }
337 
338 /**
339  * drm_sched_entity_set_priority - Sets priority of the entity
340  *
341  * @entity: scheduler entity
342  * @priority: scheduler priority
343  *
344  * Update the priority of runqueus used for the entity.
345  */
346 void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
347 				   enum drm_sched_priority priority)
348 {
349 	spin_lock(&entity->rq_lock);
350 	entity->priority = priority;
351 	spin_unlock(&entity->rq_lock);
352 }
353 EXPORT_SYMBOL(drm_sched_entity_set_priority);
354 
355 /**
356  * drm_sched_entity_add_dependency_cb - add callback for the entities dependency
357  *
358  * @entity: entity with dependency
359  *
360  * Add a callback to the current dependency of the entity to wake up the
361  * scheduler when the entity becomes available.
362  */
363 static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
364 {
365 	struct drm_gpu_scheduler *sched = entity->rq->sched;
366 	struct dma_fence *fence = entity->dependency;
367 	struct drm_sched_fence *s_fence;
368 
369 	if (fence->context == entity->fence_context ||
370 	    fence->context == entity->fence_context + 1) {
371 		/*
372 		 * Fence is a scheduled/finished fence from a job
373 		 * which belongs to the same entity, we can ignore
374 		 * fences from ourself
375 		 */
376 		dma_fence_put(entity->dependency);
377 		return false;
378 	}
379 
380 	s_fence = to_drm_sched_fence(fence);
381 	if (s_fence && s_fence->sched == sched) {
382 
383 		/*
384 		 * Fence is from the same scheduler, only need to wait for
385 		 * it to be scheduled
386 		 */
387 		fence = dma_fence_get(&s_fence->scheduled);
388 		dma_fence_put(entity->dependency);
389 		entity->dependency = fence;
390 		if (!dma_fence_add_callback(fence, &entity->cb,
391 					    drm_sched_entity_clear_dep))
392 			return true;
393 
394 		/* Ignore it when it is already scheduled */
395 		dma_fence_put(fence);
396 		return false;
397 	}
398 
399 	if (!dma_fence_add_callback(entity->dependency, &entity->cb,
400 				    drm_sched_entity_wakeup))
401 		return true;
402 
403 	dma_fence_put(entity->dependency);
404 	return false;
405 }
406 
407 /**
408  * drm_sched_entity_pop_job - get a ready to be scheduled job from the entity
409  *
410  * @entity: entity to get the job from
411  *
412  * Process all dependencies and try to get one job from the entities queue.
413  */
414 struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
415 {
416 	struct drm_gpu_scheduler *sched = entity->rq->sched;
417 	struct drm_sched_job *sched_job;
418 
419 	sched_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
420 	if (!sched_job)
421 		return NULL;
422 
423 	while ((entity->dependency =
424 			sched->ops->dependency(sched_job, entity))) {
425 		trace_drm_sched_job_wait_dep(sched_job, entity->dependency);
426 
427 		if (drm_sched_entity_add_dependency_cb(entity))
428 			return NULL;
429 	}
430 
431 	/* skip jobs from entity that marked guilty */
432 	if (entity->guilty && atomic_read(entity->guilty))
433 		dma_fence_set_error(&sched_job->s_fence->finished, -ECANCELED);
434 
435 	dma_fence_put(entity->last_scheduled);
436 	entity->last_scheduled = dma_fence_get(&sched_job->s_fence->finished);
437 
438 	spsc_queue_pop(&entity->job_queue);
439 	return sched_job;
440 }
441 
442 /**
443  * drm_sched_entity_select_rq - select a new rq for the entity
444  *
445  * @entity: scheduler entity
446  *
447  * Check all prerequisites and select a new rq for the entity for load
448  * balancing.
449  */
450 void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
451 {
452 	struct dma_fence *fence;
453 	struct drm_gpu_scheduler *sched;
454 	struct drm_sched_rq *rq;
455 
456 	if (spsc_queue_count(&entity->job_queue) || !entity->sched_list)
457 		return;
458 
459 	fence = READ_ONCE(entity->last_scheduled);
460 	if (fence && !dma_fence_is_signaled(fence))
461 		return;
462 
463 	spin_lock(&entity->rq_lock);
464 	sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
465 	rq = sched ? &sched->sched_rq[entity->priority] : NULL;
466 	if (rq != entity->rq) {
467 		drm_sched_rq_remove_entity(entity->rq, entity);
468 		entity->rq = rq;
469 	}
470 	spin_unlock(&entity->rq_lock);
471 
472 	if (entity->num_sched_list == 1)
473 		entity->sched_list = NULL;
474 }
475 
476 /**
477  * drm_sched_entity_push_job - Submit a job to the entity's job queue
478  *
479  * @sched_job: job to submit
480  * @entity: scheduler entity
481  *
482  * Note: To guarantee that the order of insertion to queue matches
483  * the job's fence sequence number this function should be
484  * called with drm_sched_job_init under common lock.
485  *
486  * Returns 0 for success, negative error code otherwise.
487  */
488 void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
489 			       struct drm_sched_entity *entity)
490 {
491 	bool first;
492 
493 	trace_drm_sched_job(sched_job, entity);
494 	atomic_inc(entity->rq->sched->score);
495 	WRITE_ONCE(entity->last_user, current->group_leader);
496 	first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
497 
498 	/* first job wakes up scheduler */
499 	if (first) {
500 		/* Add the entity to the run queue */
501 		spin_lock(&entity->rq_lock);
502 		if (entity->stopped) {
503 			spin_unlock(&entity->rq_lock);
504 
505 			DRM_ERROR("Trying to push to a killed entity\n");
506 			return;
507 		}
508 		drm_sched_rq_add_entity(entity->rq, entity);
509 		spin_unlock(&entity->rq_lock);
510 		drm_sched_wakeup(entity->rq->sched);
511 	}
512 }
513 EXPORT_SYMBOL(drm_sched_entity_push_job);
514