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 */
 53int 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}
 87EXPORT_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 */
 96void 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}
105EXPORT_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 */
114static 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	    entity->stopped)
121		return true;
122
123	return false;
124}
125
126/**
127 * drm_sched_entity_is_ready - Check if entity is ready
128 *
129 * @entity: scheduler entity
130 *
131 * Return true if entity could provide a job.
132 */
133bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
134{
135	if (spsc_queue_peek(&entity->job_queue) == NULL)
136		return false;
137
138	if (READ_ONCE(entity->dependency))
139		return false;
140
141	return true;
142}
143
144/**
145 * drm_sched_entity_flush - Flush a context entity
146 *
147 * @entity: scheduler entity
148 * @timeout: time to wait in for Q to become empty in jiffies.
149 *
150 * Splitting drm_sched_entity_fini() into two functions, The first one does the
151 * waiting, removes the entity from the runqueue and returns an error when the
152 * process was killed.
153 *
154 * Returns the remaining time in jiffies left from the input timeout
155 */
156long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
157{
158	struct drm_gpu_scheduler *sched;
159	struct task_struct *last_user;
160	long ret = timeout;
161
162	if (!entity->rq)
163		return 0;
164
165	sched = entity->rq->sched;
166	/**
167	 * The client will not queue more IBs during this fini, consume existing
168	 * queued IBs or discard them on SIGKILL
169	 */
170	if (current->flags & PF_EXITING) {
171		if (timeout)
172			ret = wait_event_timeout(
173					sched->job_scheduled,
174					drm_sched_entity_is_idle(entity),
175					timeout);
176	} else {
177		wait_event_killable(sched->job_scheduled,
178				    drm_sched_entity_is_idle(entity));
179	}
180
181	/* For killed process disable any more IBs enqueue right now */
182	last_user = cmpxchg(&entity->last_user, current->group_leader, NULL);
183	if ((!last_user || last_user == current->group_leader) &&
184	    (current->flags & PF_EXITING) && (current->exit_code == SIGKILL)) {
185		spin_lock(&entity->rq_lock);
186		entity->stopped = true;
187		drm_sched_rq_remove_entity(entity->rq, entity);
188		spin_unlock(&entity->rq_lock);
189	}
190
191	return ret;
192}
193EXPORT_SYMBOL(drm_sched_entity_flush);
194
195/**
196 * drm_sched_entity_kill_jobs_cb - helper for drm_sched_entity_kill_jobs
197 *
198 * @f: signaled fence
199 * @cb: our callback structure
200 *
201 * Signal the scheduler finished fence when the entity in question is killed.
202 */
203static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
204					  struct dma_fence_cb *cb)
205{
206	struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
207						 finish_cb);
208
209	drm_sched_fence_finished(job->s_fence);
210	WARN_ON(job->s_fence->parent);
211	job->sched->ops->free_job(job);
212}
213
214/**
215 * drm_sched_entity_kill_jobs - Make sure all remaining jobs are killed
216 *
217 * @entity: entity which is cleaned up
218 *
219 * Makes sure that all remaining jobs in an entity are killed before it is
220 * destroyed.
221 */
222static void drm_sched_entity_kill_jobs(struct drm_sched_entity *entity)
223{
224	struct drm_sched_job *job;
225	struct dma_fence *f;
226	int r;
227
228	while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {
229		struct drm_sched_fence *s_fence = job->s_fence;
230
231		/* Wait for all dependencies to avoid data corruptions */
232		while ((f = job->sched->ops->dependency(job, entity)))
233			dma_fence_wait(f, false);
234
235		drm_sched_fence_scheduled(s_fence);
236		dma_fence_set_error(&s_fence->finished, -ESRCH);
237
238		/*
239		 * When pipe is hanged by older entity, new entity might
240		 * not even have chance to submit it's first job to HW
241		 * and so entity->last_scheduled will remain NULL
242		 */
243		if (!entity->last_scheduled) {
244			drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
245			continue;
246		}
247
248		r = dma_fence_add_callback(entity->last_scheduled,
249					   &job->finish_cb,
250					   drm_sched_entity_kill_jobs_cb);
251		if (r == -ENOENT)
252			drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
253		else if (r)
254			DRM_ERROR("fence add callback failed (%d)\n", r);
255	}
256}
257
258/**
259 * drm_sched_entity_fini - Destroy a context entity
260 *
261 * @entity: scheduler entity
262 *
263 * This should be called after @drm_sched_entity_do_release. It goes over the
264 * entity and signals all jobs with an error code if the process was killed.
265 *
266 */
267void drm_sched_entity_fini(struct drm_sched_entity *entity)
268{
269	struct drm_gpu_scheduler *sched = NULL;
270
271	if (entity->rq) {
272		sched = entity->rq->sched;
273		drm_sched_rq_remove_entity(entity->rq, entity);
274	}
275
276	/* Consumption of existing IBs wasn't completed. Forcefully
277	 * remove them here.
278	 */
279	if (spsc_queue_count(&entity->job_queue)) {
280		if (sched) {
281			/*
282			 * Wait for thread to idle to make sure it isn't processing
283			 * this entity.
284			 */
285			wait_for_completion(&entity->entity_idle);
286
287		}
288		if (entity->dependency) {
289			dma_fence_remove_callback(entity->dependency,
290						  &entity->cb);
291			dma_fence_put(entity->dependency);
292			entity->dependency = NULL;
293		}
294
295		drm_sched_entity_kill_jobs(entity);
296	}
297
298	dma_fence_put(entity->last_scheduled);
299	entity->last_scheduled = NULL;
300}
301EXPORT_SYMBOL(drm_sched_entity_fini);
302
303/**
304 * drm_sched_entity_destroy - Destroy a context entity
305 *
306 * @entity: scheduler entity
307 *
308 * Calls drm_sched_entity_do_release() and drm_sched_entity_cleanup()
309 */
310void drm_sched_entity_destroy(struct drm_sched_entity *entity)
311{
312	drm_sched_entity_flush(entity, MAX_WAIT_SCHED_ENTITY_Q_EMPTY);
313	drm_sched_entity_fini(entity);
314}
315EXPORT_SYMBOL(drm_sched_entity_destroy);
316
317/*
318 * drm_sched_entity_clear_dep - callback to clear the entities dependency
319 */
320static void drm_sched_entity_clear_dep(struct dma_fence *f,
321				       struct dma_fence_cb *cb)
322{
323	struct drm_sched_entity *entity =
324		container_of(cb, struct drm_sched_entity, cb);
325
326	entity->dependency = NULL;
327	dma_fence_put(f);
328}
329
330/*
331 * drm_sched_entity_clear_dep - callback to clear the entities dependency and
332 * wake up scheduler
333 */
334static void drm_sched_entity_wakeup(struct dma_fence *f,
335				    struct dma_fence_cb *cb)
336{
337	struct drm_sched_entity *entity =
338		container_of(cb, struct drm_sched_entity, cb);
339
340	drm_sched_entity_clear_dep(f, cb);
341	drm_sched_wakeup(entity->rq->sched);
342}
343
344/**
345 * drm_sched_entity_set_priority - Sets priority of the entity
346 *
347 * @entity: scheduler entity
348 * @priority: scheduler priority
349 *
350 * Update the priority of runqueus used for the entity.
351 */
352void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
353				   enum drm_sched_priority priority)
354{
355	spin_lock(&entity->rq_lock);
356	entity->priority = priority;
357	spin_unlock(&entity->rq_lock);
358}
359EXPORT_SYMBOL(drm_sched_entity_set_priority);
360
361/**
362 * drm_sched_entity_add_dependency_cb - add callback for the entities dependency
363 *
364 * @entity: entity with dependency
365 *
366 * Add a callback to the current dependency of the entity to wake up the
367 * scheduler when the entity becomes available.
368 */
369static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
370{
371	struct drm_gpu_scheduler *sched = entity->rq->sched;
372	struct dma_fence *fence = entity->dependency;
373	struct drm_sched_fence *s_fence;
374
375	if (fence->context == entity->fence_context ||
376	    fence->context == entity->fence_context + 1) {
377		/*
378		 * Fence is a scheduled/finished fence from a job
379		 * which belongs to the same entity, we can ignore
380		 * fences from ourself
381		 */
382		dma_fence_put(entity->dependency);
383		return false;
384	}
385
386	s_fence = to_drm_sched_fence(fence);
387	if (s_fence && s_fence->sched == sched) {
388
389		/*
390		 * Fence is from the same scheduler, only need to wait for
391		 * it to be scheduled
392		 */
393		fence = dma_fence_get(&s_fence->scheduled);
394		dma_fence_put(entity->dependency);
395		entity->dependency = fence;
396		if (!dma_fence_add_callback(fence, &entity->cb,
397					    drm_sched_entity_clear_dep))
398			return true;
399
400		/* Ignore it when it is already scheduled */
401		dma_fence_put(fence);
402		return false;
403	}
404
405	if (!dma_fence_add_callback(entity->dependency, &entity->cb,
406				    drm_sched_entity_wakeup))
407		return true;
408
409	dma_fence_put(entity->dependency);
410	return false;
411}
412
413/**
414 * drm_sched_entity_pop_job - get a ready to be scheduled job from the entity
415 *
416 * @entity: entity to get the job from
417 *
418 * Process all dependencies and try to get one job from the entities queue.
419 */
420struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
421{
422	struct drm_gpu_scheduler *sched = entity->rq->sched;
423	struct drm_sched_job *sched_job;
424
425	sched_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
426	if (!sched_job)
427		return NULL;
428
429	while ((entity->dependency =
430			sched->ops->dependency(sched_job, entity))) {
431		trace_drm_sched_job_wait_dep(sched_job, entity->dependency);
432
433		if (drm_sched_entity_add_dependency_cb(entity))
434			return NULL;
435	}
436
437	/* skip jobs from entity that marked guilty */
438	if (entity->guilty && atomic_read(entity->guilty))
439		dma_fence_set_error(&sched_job->s_fence->finished, -ECANCELED);
440
441	dma_fence_put(entity->last_scheduled);
442	entity->last_scheduled = dma_fence_get(&sched_job->s_fence->finished);
443
444	spsc_queue_pop(&entity->job_queue);
445	return sched_job;
446}
447
448/**
449 * drm_sched_entity_select_rq - select a new rq for the entity
450 *
451 * @entity: scheduler entity
452 *
453 * Check all prerequisites and select a new rq for the entity for load
454 * balancing.
455 */
456void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
457{
458	struct dma_fence *fence;
459	struct drm_gpu_scheduler *sched;
460	struct drm_sched_rq *rq;
461
462	if (spsc_queue_count(&entity->job_queue) || !entity->sched_list)
463		return;
464
465	fence = READ_ONCE(entity->last_scheduled);
466	if (fence && !dma_fence_is_signaled(fence))
467		return;
468
469	spin_lock(&entity->rq_lock);
470	sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
471	rq = sched ? &sched->sched_rq[entity->priority] : NULL;
472	if (rq != entity->rq) {
473		drm_sched_rq_remove_entity(entity->rq, entity);
474		entity->rq = rq;
475	}
476	spin_unlock(&entity->rq_lock);
477
478	if (entity->num_sched_list == 1)
479		entity->sched_list = NULL;
480}
481
482/**
483 * drm_sched_entity_push_job - Submit a job to the entity's job queue
484 *
485 * @sched_job: job to submit
486 * @entity: scheduler entity
487 *
488 * Note: To guarantee that the order of insertion to queue matches
489 * the job's fence sequence number this function should be
490 * called with drm_sched_job_init under common lock.
491 *
492 * Returns 0 for success, negative error code otherwise.
493 */
494void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
495			       struct drm_sched_entity *entity)
496{
497	bool first;
498
499	trace_drm_sched_job(sched_job, entity);
500	atomic_inc(entity->rq->sched->score);
501	WRITE_ONCE(entity->last_user, current->group_leader);
502	first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
503
504	/* first job wakes up scheduler */
505	if (first) {
506		/* Add the entity to the run queue */
507		spin_lock(&entity->rq_lock);
508		if (entity->stopped) {
509			spin_unlock(&entity->rq_lock);
510
511			DRM_ERROR("Trying to push to a killed entity\n");
512			return;
513		}
514		drm_sched_rq_add_entity(entity->rq, entity);
515		spin_unlock(&entity->rq_lock);
516		drm_sched_wakeup(entity->rq->sched);
517	}
518}
519EXPORT_SYMBOL(drm_sched_entity_push_job);