drivers/gpu/drm/scheduler/gpu_scheduler.c

   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/wait.h>
  26 #include <linux/sched.h>
  27 #include <uapi/linux/sched/types.h>
  28 #include <drm/drmP.h>
  29 #include <drm/gpu_scheduler.h>
  30 #include <drm/spsc_queue.h>
  31
  32 #define CREATE_TRACE_POINTS
  33 #include <drm/gpu_scheduler_trace.h>
  34
  35 #define to_drm_sched_job(sched_job)             \
  36                 container_of((sched_job), struct drm_sched_job, queue_node)
  37
  38 static bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
  39 static void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
  40 static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb);
  41
  42 /* Initialize a given run queue struct */
  43 static void drm_sched_rq_init(struct drm_sched_rq *rq)
  44 {
  45         spin_lock_init(&rq->lock);
  46         INIT_LIST_HEAD(&rq->entities);
  47         rq->current_entity = NULL;
  48 }
  49
  50 static void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
  51                                     struct drm_sched_entity *entity)
  52 {
  53         if (!list_empty(&entity->list))
  54                 return;
  55         spin_lock(&rq->lock);
  56         list_add_tail(&entity->list, &rq->entities);
  57         spin_unlock(&rq->lock);
  58 }
  59
  60 static void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
  61                                        struct drm_sched_entity *entity)
  62 {
  63         if (list_empty(&entity->list))
  64                 return;
  65         spin_lock(&rq->lock);
  66         list_del_init(&entity->list);
  67         if (rq->current_entity == entity)
  68                 rq->current_entity = NULL;
  69         spin_unlock(&rq->lock);
  70 }
  71
  72 /**
  73  * Select an entity which could provide a job to run
  74  *
  75  * @rq          The run queue to check.
  76  *
  77  * Try to find a ready entity, returns NULL if none found.
  78  */
  79 static struct drm_sched_entity *
  80 drm_sched_rq_select_entity(struct drm_sched_rq *rq)
  81 {
  82         struct drm_sched_entity *entity;
  83
  84         spin_lock(&rq->lock);
  85
  86         entity = rq->current_entity;
  87         if (entity) {
  88                 list_for_each_entry_continue(entity, &rq->entities, list) {
  89                         if (drm_sched_entity_is_ready(entity)) {
  90                                 rq->current_entity = entity;
  91                                 spin_unlock(&rq->lock);
  92                                 return entity;
  93                         }
  94                 }
  95         }
  96
  97         list_for_each_entry(entity, &rq->entities, list) {
  98
  99                 if (drm_sched_entity_is_ready(entity)) {
 100                         rq->current_entity = entity;
 101                         spin_unlock(&rq->lock);
 102                         return entity;
 103                 }
 104
 105                 if (entity == rq->current_entity)
 106                         break;
 107         }
 108
 109         spin_unlock(&rq->lock);
 110
 111         return NULL;
 112 }
 113
 114 /**
 115  * Init a context entity used by scheduler when submit to HW ring.
 116  *
 117  * @sched       The pointer to the scheduler
 118  * @entity      The pointer to a valid drm_sched_entity
 119  * @rq          The run queue this entity belongs
 120  * @kernel      If this is an entity for the kernel
 121  * @jobs        The max number of jobs in the job queue
 122  *
 123  * return 0 if succeed. negative error code on failure
 124 */
 125 int drm_sched_entity_init(struct drm_gpu_scheduler *sched,
 126                           struct drm_sched_entity *entity,
 127                           struct drm_sched_rq *rq,
 128                           uint32_t jobs, atomic_t *guilty)
 129 {
 130         if (!(sched && entity && rq))
 131                 return -EINVAL;
 132
 133         memset(entity, 0, sizeof(struct drm_sched_entity));
 134         INIT_LIST_HEAD(&entity->list);
 135         entity->rq = rq;
 136         entity->sched = sched;
 137         entity->guilty = guilty;
 138
 139         spin_lock_init(&entity->rq_lock);
 140         spin_lock_init(&entity->queue_lock);
 141         spsc_queue_init(&entity->job_queue);
 142
 143         atomic_set(&entity->fence_seq, 0);
 144         entity->fence_context = dma_fence_context_alloc(2);
 145
 146         return 0;
 147 }
 148 EXPORT_SYMBOL(drm_sched_entity_init);
 149
 150 /**
 151  * Query if entity is initialized
 152  *
 153  * @sched       Pointer to scheduler instance
 154  * @entity      The pointer to a valid scheduler entity
 155  *
 156  * return true if entity is initialized, false otherwise
 157 */
 158 static bool drm_sched_entity_is_initialized(struct drm_gpu_scheduler *sched,
 159                                             struct drm_sched_entity *entity)
 160 {
 161         return entity->sched == sched &&
 162                 entity->rq != NULL;
 163 }
 164
 165 /**
 166  * Check if entity is idle
 167  *
 168  * @entity      The pointer to a valid scheduler entity
 169  *
 170  * Return true if entity don't has any unscheduled jobs.
 171  */
 172 static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity)
 173 {
 174         rmb();
 175         if (spsc_queue_peek(&entity->job_queue) == NULL)
 176                 return true;
 177
 178         return false;
 179 }
 180
 181 /**
 182  * Check if entity is ready
 183  *
 184  * @entity      The pointer to a valid scheduler entity
 185  *
 186  * Return true if entity could provide a job.
 187  */
 188 static bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
 189 {
 190         if (spsc_queue_peek(&entity->job_queue) == NULL)
 191                 return false;
 192
 193         if (READ_ONCE(entity->dependency))
 194                 return false;
 195
 196         return true;
 197 }
 198
 199 /**
 200  * Destroy a context entity
 201  *
 202  * @sched       Pointer to scheduler instance
 203  * @entity      The pointer to a valid scheduler entity
 204  *
 205  * Cleanup and free the allocated resources.
 206  */
 207 void drm_sched_entity_fini(struct drm_gpu_scheduler *sched,
 208                            struct drm_sched_entity *entity)
 209 {
 210         int r;
 211
 212         if (!drm_sched_entity_is_initialized(sched, entity))
 213                 return;
 214         /**
 215          * The client will not queue more IBs during this fini, consume existing
 216          * queued IBs or discard them on SIGKILL
 217         */
 218         if ((current->flags & PF_SIGNALED) && current->exit_code == SIGKILL)
 219                 r = -ERESTARTSYS;
 220         else
 221                 r = wait_event_killable(sched->job_scheduled,
 222                                         drm_sched_entity_is_idle(entity));
 223         drm_sched_entity_set_rq(entity, NULL);
 224         if (r) {
 225                 struct drm_sched_job *job;
 226
 227                 /* Park the kernel for a moment to make sure it isn't processing
 228                  * our enity.
 229                  */
 230                 kthread_park(sched->thread);
 231                 kthread_unpark(sched->thread);
 232                 if (entity->dependency) {
 233                         dma_fence_remove_callback(entity->dependency,
 234                                                   &entity->cb);
 235                         dma_fence_put(entity->dependency);
 236                         entity->dependency = NULL;
 237                 }
 238
 239                 while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {
 240                         struct drm_sched_fence *s_fence = job->s_fence;
 241                         drm_sched_fence_scheduled(s_fence);
 242                         dma_fence_set_error(&s_fence->finished, -ESRCH);
 243                         drm_sched_fence_finished(s_fence);
 244                         WARN_ON(s_fence->parent);
 245                         dma_fence_put(&s_fence->finished);
 246                         sched->ops->free_job(job);
 247                 }
 248         }
 249 }
 250 EXPORT_SYMBOL(drm_sched_entity_fini);
 251
 252 static void drm_sched_entity_wakeup(struct dma_fence *f, struct dma_fence_cb *cb)
 253 {
 254         struct drm_sched_entity *entity =
 255                 container_of(cb, struct drm_sched_entity, cb);
 256         entity->dependency = NULL;
 257         dma_fence_put(f);
 258         drm_sched_wakeup(entity->sched);
 259 }
 260
 261 static void drm_sched_entity_clear_dep(struct dma_fence *f, struct dma_fence_cb *cb)
 262 {
 263         struct drm_sched_entity *entity =
 264                 container_of(cb, struct drm_sched_entity, cb);
 265         entity->dependency = NULL;
 266         dma_fence_put(f);
 267 }
 268
 269 void drm_sched_entity_set_rq(struct drm_sched_entity *entity,
 270                              struct drm_sched_rq *rq)
 271 {
 272         if (entity->rq == rq)
 273                 return;
 274
 275         spin_lock(&entity->rq_lock);
 276
 277         if (entity->rq)
 278                 drm_sched_rq_remove_entity(entity->rq, entity);
 279
 280         entity->rq = rq;
 281         if (rq)
 282                 drm_sched_rq_add_entity(rq, entity);
 283
 284         spin_unlock(&entity->rq_lock);
 285 }
 286 EXPORT_SYMBOL(drm_sched_entity_set_rq);
 287
 288 bool drm_sched_dependency_optimized(struct dma_fence* fence,
 289                                     struct drm_sched_entity *entity)
 290 {
 291         struct drm_gpu_scheduler *sched = entity->sched;
 292         struct drm_sched_fence *s_fence;
 293
 294         if (!fence || dma_fence_is_signaled(fence))
 295                 return false;
 296         if (fence->context == entity->fence_context)
 297                 return true;
 298         s_fence = to_drm_sched_fence(fence);
 299         if (s_fence && s_fence->sched == sched)
 300                 return true;
 301
 302         return false;
 303 }
 304 EXPORT_SYMBOL(drm_sched_dependency_optimized);
 305
 306 static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
 307 {
 308         struct drm_gpu_scheduler *sched = entity->sched;
 309         struct dma_fence * fence = entity->dependency;
 310         struct drm_sched_fence *s_fence;
 311
 312         if (fence->context == entity->fence_context) {
 313                 /* We can ignore fences from ourself */
 314                 dma_fence_put(entity->dependency);
 315                 return false;
 316         }
 317
 318         s_fence = to_drm_sched_fence(fence);
 319         if (s_fence && s_fence->sched == sched) {
 320
 321                 /*
 322                  * Fence is from the same scheduler, only need to wait for
 323                  * it to be scheduled
 324                  */
 325                 fence = dma_fence_get(&s_fence->scheduled);
 326                 dma_fence_put(entity->dependency);
 327                 entity->dependency = fence;
 328                 if (!dma_fence_add_callback(fence, &entity->cb,
 329                                             drm_sched_entity_clear_dep))
 330                         return true;
 331
 332                 /* Ignore it when it is already scheduled */
 333                 dma_fence_put(fence);
 334                 return false;
 335         }
 336
 337         if (!dma_fence_add_callback(entity->dependency, &entity->cb,
 338                                     drm_sched_entity_wakeup))
 339                 return true;
 340
 341         dma_fence_put(entity->dependency);
 342         return false;
 343 }
 344
 345 static struct drm_sched_job *
 346 drm_sched_entity_pop_job(struct drm_sched_entity *entity)
 347 {
 348         struct drm_gpu_scheduler *sched = entity->sched;
 349         struct drm_sched_job *sched_job = to_drm_sched_job(
 350                                                 spsc_queue_peek(&entity->job_queue));
 351
 352         if (!sched_job)
 353                 return NULL;
 354
 355         while ((entity->dependency = sched->ops->dependency(sched_job, entity)))
 356                 if (drm_sched_entity_add_dependency_cb(entity))
 357                         return NULL;
 358
 359         /* skip jobs from entity that marked guilty */
 360         if (entity->guilty && atomic_read(entity->guilty))
 361                 dma_fence_set_error(&sched_job->s_fence->finished, -ECANCELED);
 362
 363         spsc_queue_pop(&entity->job_queue);
 364         return sched_job;
 365 }
 366
 367 /**
 368  * Submit a job to the job queue
 369  *
 370  * @sched_job           The pointer to job required to submit
 371  *
 372  * Returns 0 for success, negative error code otherwise.
 373  */
 374 void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
 375                                struct drm_sched_entity *entity)
 376 {
 377         struct drm_gpu_scheduler *sched = sched_job->sched;
 378         bool first = false;
 379
 380         trace_drm_sched_job(sched_job, entity);
 381
 382         spin_lock(&entity->queue_lock);
 383         first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
 384
 385         spin_unlock(&entity->queue_lock);
 386
 387         /* first job wakes up scheduler */
 388         if (first) {
 389                 /* Add the entity to the run queue */
 390                 spin_lock(&entity->rq_lock);
 391                 drm_sched_rq_add_entity(entity->rq, entity);
 392                 spin_unlock(&entity->rq_lock);
 393                 drm_sched_wakeup(sched);
 394         }
 395 }
 396 EXPORT_SYMBOL(drm_sched_entity_push_job);
 397
 398 /* job_finish is called after hw fence signaled
 399  */
 400 static void drm_sched_job_finish(struct work_struct *work)
 401 {
 402         struct drm_sched_job *s_job = container_of(work, struct drm_sched_job,
 403                                                    finish_work);
 404         struct drm_gpu_scheduler *sched = s_job->sched;
 405
 406         /* remove job from ring_mirror_list */
 407         spin_lock(&sched->job_list_lock);
 408         list_del_init(&s_job->node);
 409         if (sched->timeout != MAX_SCHEDULE_TIMEOUT) {
 410                 struct drm_sched_job *next;
 411
 412                 spin_unlock(&sched->job_list_lock);
 413                 cancel_delayed_work_sync(&s_job->work_tdr);
 414                 spin_lock(&sched->job_list_lock);
 415
 416                 /* queue TDR for next job */
 417                 next = list_first_entry_or_null(&sched->ring_mirror_list,
 418                                                 struct drm_sched_job, node);
 419
 420                 if (next)
 421                         schedule_delayed_work(&next->work_tdr, sched->timeout);
 422         }
 423         spin_unlock(&sched->job_list_lock);
 424         dma_fence_put(&s_job->s_fence->finished);
 425         sched->ops->free_job(s_job);
 426 }
 427
 428 static void drm_sched_job_finish_cb(struct dma_fence *f,
 429                                     struct dma_fence_cb *cb)
 430 {
 431         struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
 432                                                  finish_cb);
 433         schedule_work(&job->finish_work);
 434 }
 435
 436 static void drm_sched_job_begin(struct drm_sched_job *s_job)
 437 {
 438         struct drm_gpu_scheduler *sched = s_job->sched;
 439
 440         dma_fence_add_callback(&s_job->s_fence->finished, &s_job->finish_cb,
 441                                drm_sched_job_finish_cb);
 442
 443         spin_lock(&sched->job_list_lock);
 444         list_add_tail(&s_job->node, &sched->ring_mirror_list);
 445         if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
 446             list_first_entry_or_null(&sched->ring_mirror_list,
 447                                      struct drm_sched_job, node) == s_job)
 448                 schedule_delayed_work(&s_job->work_tdr, sched->timeout);
 449         spin_unlock(&sched->job_list_lock);
 450 }
 451
 452 static void drm_sched_job_timedout(struct work_struct *work)
 453 {
 454         struct drm_sched_job *job = container_of(work, struct drm_sched_job,
 455                                                  work_tdr.work);
 456
 457         job->sched->ops->timedout_job(job);
 458 }
 459
 460 void drm_sched_hw_job_reset(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
 461 {
 462         struct drm_sched_job *s_job;
 463         struct drm_sched_entity *entity, *tmp;
 464         int i;
 465
 466         spin_lock(&sched->job_list_lock);
 467         list_for_each_entry_reverse(s_job, &sched->ring_mirror_list, node) {
 468                 if (s_job->s_fence->parent &&
 469                     dma_fence_remove_callback(s_job->s_fence->parent,
 470                                               &s_job->s_fence->cb)) {
 471                         dma_fence_put(s_job->s_fence->parent);
 472                         s_job->s_fence->parent = NULL;
 473                         atomic_dec(&sched->hw_rq_count);
 474                 }
 475         }
 476         spin_unlock(&sched->job_list_lock);
 477
 478         if (bad && bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
 479                 atomic_inc(&bad->karma);
 480                 /* don't increase @bad's karma if it's from KERNEL RQ,
 481                  * becuase sometimes GPU hang would cause kernel jobs (like VM updating jobs)
 482                  * corrupt but keep in mind that kernel jobs always considered good.
 483                  */
 484                 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL; i++ ) {
 485                         struct drm_sched_rq *rq = &sched->sched_rq[i];
 486
 487                         spin_lock(&rq->lock);
 488                         list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
 489                                 if (bad->s_fence->scheduled.context == entity->fence_context) {
 490                                     if (atomic_read(&bad->karma) > bad->sched->hang_limit)
 491                                                 if (entity->guilty)
 492                                                         atomic_set(entity->guilty, 1);
 493                                         break;
 494                                 }
 495                         }
 496                         spin_unlock(&rq->lock);
 497                         if (&entity->list != &rq->entities)
 498                                 break;
 499                 }
 500         }
 501 }
 502 EXPORT_SYMBOL(drm_sched_hw_job_reset);
 503
 504 void drm_sched_job_recovery(struct drm_gpu_scheduler *sched)
 505 {
 506         struct drm_sched_job *s_job, *tmp;
 507         bool found_guilty = false;
 508         int r;
 509
 510         spin_lock(&sched->job_list_lock);
 511         s_job = list_first_entry_or_null(&sched->ring_mirror_list,
 512                                          struct drm_sched_job, node);
 513         if (s_job && sched->timeout != MAX_SCHEDULE_TIMEOUT)
 514                 schedule_delayed_work(&s_job->work_tdr, sched->timeout);
 515
 516         list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
 517                 struct drm_sched_fence *s_fence = s_job->s_fence;
 518                 struct dma_fence *fence;
 519                 uint64_t guilty_context;
 520
 521                 if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
 522                         found_guilty = true;
 523                         guilty_context = s_job->s_fence->scheduled.context;
 524                 }
 525
 526                 if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
 527                         dma_fence_set_error(&s_fence->finished, -ECANCELED);
 528
 529                 spin_unlock(&sched->job_list_lock);
 530                 fence = sched->ops->run_job(s_job);
 531                 atomic_inc(&sched->hw_rq_count);
 532                 if (fence) {
 533                         s_fence->parent = dma_fence_get(fence);
 534                         r = dma_fence_add_callback(fence, &s_fence->cb,
 535                                                    drm_sched_process_job);
 536                         if (r == -ENOENT)
 537                                 drm_sched_process_job(fence, &s_fence->cb);
 538                         else if (r)
 539                                 DRM_ERROR("fence add callback failed (%d)\n",
 540                                           r);
 541                         dma_fence_put(fence);
 542                 } else {
 543                         drm_sched_process_job(NULL, &s_fence->cb);
 544                 }
 545                 spin_lock(&sched->job_list_lock);
 546         }
 547         spin_unlock(&sched->job_list_lock);
 548 }
 549 EXPORT_SYMBOL(drm_sched_job_recovery);
 550
 551 /* init a sched_job with basic field */
 552 int drm_sched_job_init(struct drm_sched_job *job,
 553                        struct drm_gpu_scheduler *sched,
 554                        struct drm_sched_entity *entity,
 555                        void *owner)
 556 {
 557         job->sched = sched;
 558         job->s_priority = entity->rq - sched->sched_rq;
 559         job->s_fence = drm_sched_fence_create(entity, owner);
 560         if (!job->s_fence)
 561                 return -ENOMEM;
 562         job->id = atomic64_inc_return(&sched->job_id_count);
 563
 564         INIT_WORK(&job->finish_work, drm_sched_job_finish);
 565         INIT_LIST_HEAD(&job->node);
 566         INIT_DELAYED_WORK(&job->work_tdr, drm_sched_job_timedout);
 567
 568         return 0;
 569 }
 570 EXPORT_SYMBOL(drm_sched_job_init);
 571
 572 /**
 573  * Return ture if we can push more jobs to the hw.
 574  */
 575 static bool drm_sched_ready(struct drm_gpu_scheduler *sched)
 576 {
 577         return atomic_read(&sched->hw_rq_count) <
 578                 sched->hw_submission_limit;
 579 }
 580
 581 /**
 582  * Wake up the scheduler when it is ready
 583  */
 584 static void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
 585 {
 586         if (drm_sched_ready(sched))
 587                 wake_up_interruptible(&sched->wake_up_worker);
 588 }
 589
 590 /**
 591  * Select next entity to process
 592 */
 593 static struct drm_sched_entity *
 594 drm_sched_select_entity(struct drm_gpu_scheduler *sched)
 595 {
 596         struct drm_sched_entity *entity;
 597         int i;
 598
 599         if (!drm_sched_ready(sched))
 600                 return NULL;
 601
 602         /* Kernel run queue has higher priority than normal run queue*/
 603         for (i = DRM_SCHED_PRIORITY_MAX - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
 604                 entity = drm_sched_rq_select_entity(&sched->sched_rq[i]);
 605                 if (entity)
 606                         break;
 607         }
 608
 609         return entity;
 610 }
 611
 612 static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb)
 613 {
 614         struct drm_sched_fence *s_fence =
 615                 container_of(cb, struct drm_sched_fence, cb);
 616         struct drm_gpu_scheduler *sched = s_fence->sched;
 617
 618         dma_fence_get(&s_fence->finished);
 619         atomic_dec(&sched->hw_rq_count);
 620         drm_sched_fence_finished(s_fence);
 621
 622         trace_drm_sched_process_job(s_fence);
 623         dma_fence_put(&s_fence->finished);
 624         wake_up_interruptible(&sched->wake_up_worker);
 625 }
 626
 627 static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
 628 {
 629         if (kthread_should_park()) {
 630                 kthread_parkme();
 631                 return true;
 632         }
 633
 634         return false;
 635 }
 636
 637 static int drm_sched_main(void *param)
 638 {
 639         struct sched_param sparam = {.sched_priority = 1};
 640         struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
 641         int r;
 642
 643         sched_setscheduler(current, SCHED_FIFO, &sparam);
 644
 645         while (!kthread_should_stop()) {
 646                 struct drm_sched_entity *entity = NULL;
 647                 struct drm_sched_fence *s_fence;
 648                 struct drm_sched_job *sched_job;
 649                 struct dma_fence *fence;
 650
 651                 wait_event_interruptible(sched->wake_up_worker,
 652                                          (!drm_sched_blocked(sched) &&
 653                                           (entity = drm_sched_select_entity(sched))) ||
 654                                          kthread_should_stop());
 655
 656                 if (!entity)
 657                         continue;
 658
 659                 sched_job = drm_sched_entity_pop_job(entity);
 660                 if (!sched_job)
 661                         continue;
 662
 663                 s_fence = sched_job->s_fence;
 664
 665                 atomic_inc(&sched->hw_rq_count);
 666                 drm_sched_job_begin(sched_job);
 667
 668                 fence = sched->ops->run_job(sched_job);
 669                 drm_sched_fence_scheduled(s_fence);
 670
 671                 if (fence) {
 672                         s_fence->parent = dma_fence_get(fence);
 673                         r = dma_fence_add_callback(fence, &s_fence->cb,
 674                                                    drm_sched_process_job);
 675                         if (r == -ENOENT)
 676                                 drm_sched_process_job(fence, &s_fence->cb);
 677                         else if (r)
 678                                 DRM_ERROR("fence add callback failed (%d)\n",
 679                                           r);
 680                         dma_fence_put(fence);
 681                 } else {
 682                         drm_sched_process_job(NULL, &s_fence->cb);
 683                 }
 684
 685                 wake_up(&sched->job_scheduled);
 686         }
 687         return 0;
 688 }
 689
 690 /**
 691  * Init a gpu scheduler instance
 692  *
 693  * @sched               The pointer to the scheduler
 694  * @ops                 The backend operations for this scheduler.
 695  * @hw_submissions      Number of hw submissions to do.
 696  * @name                Name used for debugging
 697  *
 698  * Return 0 on success, otherwise error code.
 699 */
 700 int drm_sched_init(struct drm_gpu_scheduler *sched,
 701                    const struct drm_sched_backend_ops *ops,
 702                    unsigned hw_submission,
 703                    unsigned hang_limit,
 704                    long timeout,
 705                    const char *name)
 706 {
 707         int i;
 708         sched->ops = ops;
 709         sched->hw_submission_limit = hw_submission;
 710         sched->name = name;
 711         sched->timeout = timeout;
 712         sched->hang_limit = hang_limit;
 713         for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_MAX; i++)
 714                 drm_sched_rq_init(&sched->sched_rq[i]);
 715
 716         init_waitqueue_head(&sched->wake_up_worker);
 717         init_waitqueue_head(&sched->job_scheduled);
 718         INIT_LIST_HEAD(&sched->ring_mirror_list);
 719         spin_lock_init(&sched->job_list_lock);
 720         atomic_set(&sched->hw_rq_count, 0);
 721         atomic64_set(&sched->job_id_count, 0);
 722
 723         /* Each scheduler will run on a seperate kernel thread */
 724         sched->thread = kthread_run(drm_sched_main, sched, sched->name);
 725         if (IS_ERR(sched->thread)) {
 726                 DRM_ERROR("Failed to create scheduler for %s.\n", name);
 727                 return PTR_ERR(sched->thread);
 728         }
 729
 730         return 0;
 731 }
 732 EXPORT_SYMBOL(drm_sched_init);
 733
 734 /**
 735  * Destroy a gpu scheduler
 736  *
 737  * @sched       The pointer to the scheduler
 738  */
 739 void drm_sched_fini(struct drm_gpu_scheduler *sched)
 740 {
 741         if (sched->thread)
 742                 kthread_stop(sched->thread);
 743 }
 744 EXPORT_SYMBOL(drm_sched_fini);