drivers/gpu/drm/scheduler/sched_main.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 /**
  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 <linux/dma-resv.h>
  52 #include <uapi/linux/sched/types.h>
  53
  54 #include <drm/drm_print.h>
  55 #include <drm/drm_gem.h>
  56 #include <drm/gpu_scheduler.h>
  57 #include <drm/spsc_queue.h>
  58
  59 #define CREATE_TRACE_POINTS
  60 #include "gpu_scheduler_trace.h"
  61
  62 #define to_drm_sched_job(sched_job)             \
  63                 container_of((sched_job), struct drm_sched_job, queue_node)
  64
  65 /**
  66  * drm_sched_rq_init - initialize a given run queue struct
  67  *
  68  * @sched: scheduler instance to associate with this run queue
  69  * @rq: scheduler run queue
  70  *
  71  * Initializes a scheduler runqueue.
  72  */
  73 static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
  74                               struct drm_sched_rq *rq)
  75 {
  76         spin_lock_init(&rq->lock);
  77         INIT_LIST_HEAD(&rq->entities);
  78         rq->current_entity = NULL;
  79         rq->sched = sched;
  80 }
  81
  82 /**
  83  * drm_sched_rq_add_entity - add an entity
  84  *
  85  * @rq: scheduler run queue
  86  * @entity: scheduler entity
  87  *
  88  * Adds a scheduler entity to the run queue.
  89  */
  90 void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
  91                              struct drm_sched_entity *entity)
  92 {
  93         if (!list_empty(&entity->list))
  94                 return;
  95         spin_lock(&rq->lock);
  96         atomic_inc(rq->sched->score);
  97         list_add_tail(&entity->list, &rq->entities);
  98         spin_unlock(&rq->lock);
  99 }
 100
 101 /**
 102  * drm_sched_rq_remove_entity - remove an entity
 103  *
 104  * @rq: scheduler run queue
 105  * @entity: scheduler entity
 106  *
 107  * Removes a scheduler entity from the run queue.
 108  */
 109 void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
 110                                 struct drm_sched_entity *entity)
 111 {
 112         if (list_empty(&entity->list))
 113                 return;
 114         spin_lock(&rq->lock);
 115         atomic_dec(rq->sched->score);
 116         list_del_init(&entity->list);
 117         if (rq->current_entity == entity)
 118                 rq->current_entity = NULL;
 119         spin_unlock(&rq->lock);
 120 }
 121
 122 /**
 123  * drm_sched_rq_select_entity - Select an entity which could provide a job to run
 124  *
 125  * @rq: scheduler run queue to check.
 126  *
 127  * Try to find a ready entity, returns NULL if none found.
 128  */
 129 static struct drm_sched_entity *
 130 drm_sched_rq_select_entity(struct drm_sched_rq *rq)
 131 {
 132         struct drm_sched_entity *entity;
 133
 134         spin_lock(&rq->lock);
 135
 136         entity = rq->current_entity;
 137         if (entity) {
 138                 list_for_each_entry_continue(entity, &rq->entities, list) {
 139                         if (drm_sched_entity_is_ready(entity)) {
 140                                 rq->current_entity = entity;
 141                                 reinit_completion(&entity->entity_idle);
 142                                 spin_unlock(&rq->lock);
 143                                 return entity;
 144                         }
 145                 }
 146         }
 147
 148         list_for_each_entry(entity, &rq->entities, list) {
 149
 150                 if (drm_sched_entity_is_ready(entity)) {
 151                         rq->current_entity = entity;
 152                         reinit_completion(&entity->entity_idle);
 153                         spin_unlock(&rq->lock);
 154                         return entity;
 155                 }
 156
 157                 if (entity == rq->current_entity)
 158                         break;
 159         }
 160
 161         spin_unlock(&rq->lock);
 162
 163         return NULL;
 164 }
 165
 166 /**
 167  * drm_sched_job_done - complete a job
 168  * @s_job: pointer to the job which is done
 169  *
 170  * Finish the job's fence and wake up the worker thread.
 171  */
 172 static void drm_sched_job_done(struct drm_sched_job *s_job)
 173 {
 174         struct drm_sched_fence *s_fence = s_job->s_fence;
 175         struct drm_gpu_scheduler *sched = s_fence->sched;
 176
 177         atomic_dec(&sched->hw_rq_count);
 178         atomic_dec(sched->score);
 179
 180         trace_drm_sched_process_job(s_fence);
 181
 182         dma_fence_get(&s_fence->finished);
 183         drm_sched_fence_finished(s_fence);
 184         dma_fence_put(&s_fence->finished);
 185         wake_up_interruptible(&sched->wake_up_worker);
 186 }
 187
 188 /**
 189  * drm_sched_job_done_cb - the callback for a done job
 190  * @f: fence
 191  * @cb: fence callbacks
 192  */
 193 static void drm_sched_job_done_cb(struct dma_fence *f, struct dma_fence_cb *cb)
 194 {
 195         struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
 196
 197         drm_sched_job_done(s_job);
 198 }
 199
 200 /**
 201  * drm_sched_dependency_optimized
 202  *
 203  * @fence: the dependency fence
 204  * @entity: the entity which depends on the above fence
 205  *
 206  * Returns true if the dependency can be optimized and false otherwise
 207  */
 208 bool drm_sched_dependency_optimized(struct dma_fence* fence,
 209                                     struct drm_sched_entity *entity)
 210 {
 211         struct drm_gpu_scheduler *sched = entity->rq->sched;
 212         struct drm_sched_fence *s_fence;
 213
 214         if (!fence || dma_fence_is_signaled(fence))
 215                 return false;
 216         if (fence->context == entity->fence_context)
 217                 return true;
 218         s_fence = to_drm_sched_fence(fence);
 219         if (s_fence && s_fence->sched == sched)
 220                 return true;
 221
 222         return false;
 223 }
 224 EXPORT_SYMBOL(drm_sched_dependency_optimized);
 225
 226 /**
 227  * drm_sched_start_timeout - start timeout for reset worker
 228  *
 229  * @sched: scheduler instance to start the worker for
 230  *
 231  * Start the timeout for the given scheduler.
 232  */
 233 static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched)
 234 {
 235         if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
 236             !list_empty(&sched->pending_list))
 237                 queue_delayed_work(sched->timeout_wq, &sched->work_tdr, sched->timeout);
 238 }
 239
 240 /**
 241  * drm_sched_fault - immediately start timeout handler
 242  *
 243  * @sched: scheduler where the timeout handling should be started.
 244  *
 245  * Start timeout handling immediately when the driver detects a hardware fault.
 246  */
 247 void drm_sched_fault(struct drm_gpu_scheduler *sched)
 248 {
 249         mod_delayed_work(sched->timeout_wq, &sched->work_tdr, 0);
 250 }
 251 EXPORT_SYMBOL(drm_sched_fault);
 252
 253 /**
 254  * drm_sched_suspend_timeout - Suspend scheduler job timeout
 255  *
 256  * @sched: scheduler instance for which to suspend the timeout
 257  *
 258  * Suspend the delayed work timeout for the scheduler. This is done by
 259  * modifying the delayed work timeout to an arbitrary large value,
 260  * MAX_SCHEDULE_TIMEOUT in this case.
 261  *
 262  * Returns the timeout remaining
 263  *
 264  */
 265 unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched)
 266 {
 267         unsigned long sched_timeout, now = jiffies;
 268
 269         sched_timeout = sched->work_tdr.timer.expires;
 270
 271         /*
 272          * Modify the timeout to an arbitrarily large value. This also prevents
 273          * the timeout to be restarted when new submissions arrive
 274          */
 275         if (mod_delayed_work(sched->timeout_wq, &sched->work_tdr, MAX_SCHEDULE_TIMEOUT)
 276                         && time_after(sched_timeout, now))
 277                 return sched_timeout - now;
 278         else
 279                 return sched->timeout;
 280 }
 281 EXPORT_SYMBOL(drm_sched_suspend_timeout);
 282
 283 /**
 284  * drm_sched_resume_timeout - Resume scheduler job timeout
 285  *
 286  * @sched: scheduler instance for which to resume the timeout
 287  * @remaining: remaining timeout
 288  *
 289  * Resume the delayed work timeout for the scheduler.
 290  */
 291 void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
 292                 unsigned long remaining)
 293 {
 294         spin_lock(&sched->job_list_lock);
 295
 296         if (list_empty(&sched->pending_list))
 297                 cancel_delayed_work(&sched->work_tdr);
 298         else
 299                 mod_delayed_work(sched->timeout_wq, &sched->work_tdr, remaining);
 300
 301         spin_unlock(&sched->job_list_lock);
 302 }
 303 EXPORT_SYMBOL(drm_sched_resume_timeout);
 304
 305 static void drm_sched_job_begin(struct drm_sched_job *s_job)
 306 {
 307         struct drm_gpu_scheduler *sched = s_job->sched;
 308
 309         spin_lock(&sched->job_list_lock);
 310         list_add_tail(&s_job->list, &sched->pending_list);
 311         drm_sched_start_timeout(sched);
 312         spin_unlock(&sched->job_list_lock);
 313 }
 314
 315 static void drm_sched_job_timedout(struct work_struct *work)
 316 {
 317         struct drm_gpu_scheduler *sched;
 318         struct drm_sched_job *job;
 319         enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
 320
 321         sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
 322
 323         /* Protects against concurrent deletion in drm_sched_get_cleanup_job */
 324         spin_lock(&sched->job_list_lock);
 325         job = list_first_entry_or_null(&sched->pending_list,
 326                                        struct drm_sched_job, list);
 327
 328         if (job) {
 329                 /*
 330                  * Remove the bad job so it cannot be freed by concurrent
 331                  * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
 332                  * is parked at which point it's safe.
 333                  */
 334                 list_del_init(&job->list);
 335                 spin_unlock(&sched->job_list_lock);
 336
 337                 status = job->sched->ops->timedout_job(job);
 338
 339                 /*
 340                  * Guilty job did complete and hence needs to be manually removed
 341                  * See drm_sched_stop doc.
 342                  */
 343                 if (sched->free_guilty) {
 344                         job->sched->ops->free_job(job);
 345                         sched->free_guilty = false;
 346                 }
 347         } else {
 348                 spin_unlock(&sched->job_list_lock);
 349         }
 350
 351         if (status != DRM_GPU_SCHED_STAT_ENODEV) {
 352                 spin_lock(&sched->job_list_lock);
 353                 drm_sched_start_timeout(sched);
 354                 spin_unlock(&sched->job_list_lock);
 355         }
 356 }
 357
 358  /**
 359   * drm_sched_increase_karma - Update sched_entity guilty flag
 360   *
 361   * @bad: The job guilty of time out
 362   *
 363   * Increment on every hang caused by the 'bad' job. If this exceeds the hang
 364   * limit of the scheduler then the respective sched entity is marked guilty and
 365   * jobs from it will not be scheduled further
 366   */
 367 void drm_sched_increase_karma(struct drm_sched_job *bad)
 368 {
 369         drm_sched_increase_karma_ext(bad, 1);
 370 }
 371 EXPORT_SYMBOL(drm_sched_increase_karma);
 372
 373 void drm_sched_reset_karma(struct drm_sched_job *bad)
 374 {
 375         drm_sched_increase_karma_ext(bad, 0);
 376 }
 377 EXPORT_SYMBOL(drm_sched_reset_karma);
 378
 379 /**
 380  * drm_sched_stop - stop the scheduler
 381  *
 382  * @sched: scheduler instance
 383  * @bad: job which caused the time out
 384  *
 385  * Stop the scheduler and also removes and frees all completed jobs.
 386  * Note: bad job will not be freed as it might be used later and so it's
 387  * callers responsibility to release it manually if it's not part of the
 388  * pending list any more.
 389  *
 390  */
 391 void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
 392 {
 393         struct drm_sched_job *s_job, *tmp;
 394
 395         kthread_park(sched->thread);
 396
 397         /*
 398          * Reinsert back the bad job here - now it's safe as
 399          * drm_sched_get_cleanup_job cannot race against us and release the
 400          * bad job at this point - we parked (waited for) any in progress
 401          * (earlier) cleanups and drm_sched_get_cleanup_job will not be called
 402          * now until the scheduler thread is unparked.
 403          */
 404         if (bad && bad->sched == sched)
 405                 /*
 406                  * Add at the head of the queue to reflect it was the earliest
 407                  * job extracted.
 408                  */
 409                 list_add(&bad->list, &sched->pending_list);
 410
 411         /*
 412          * Iterate the job list from later to  earlier one and either deactive
 413          * their HW callbacks or remove them from pending list if they already
 414          * signaled.
 415          * This iteration is thread safe as sched thread is stopped.
 416          */
 417         list_for_each_entry_safe_reverse(s_job, tmp, &sched->pending_list,
 418                                          list) {
 419                 if (s_job->s_fence->parent &&
 420                     dma_fence_remove_callback(s_job->s_fence->parent,
 421                                               &s_job->cb)) {
 422                         atomic_dec(&sched->hw_rq_count);
 423                 } else {
 424                         /*
 425                          * remove job from pending_list.
 426                          * Locking here is for concurrent resume timeout
 427                          */
 428                         spin_lock(&sched->job_list_lock);
 429                         list_del_init(&s_job->list);
 430                         spin_unlock(&sched->job_list_lock);
 431
 432                         /*
 433                          * Wait for job's HW fence callback to finish using s_job
 434                          * before releasing it.
 435                          *
 436                          * Job is still alive so fence refcount at least 1
 437                          */
 438                         dma_fence_wait(&s_job->s_fence->finished, false);
 439
 440                         /*
 441                          * We must keep bad job alive for later use during
 442                          * recovery by some of the drivers but leave a hint
 443                          * that the guilty job must be released.
 444                          */
 445                         if (bad != s_job)
 446                                 sched->ops->free_job(s_job);
 447                         else
 448                                 sched->free_guilty = true;
 449                 }
 450         }
 451
 452         /*
 453          * Stop pending timer in flight as we rearm it in  drm_sched_start. This
 454          * avoids the pending timeout work in progress to fire right away after
 455          * this TDR finished and before the newly restarted jobs had a
 456          * chance to complete.
 457          */
 458         cancel_delayed_work(&sched->work_tdr);
 459 }
 460
 461 EXPORT_SYMBOL(drm_sched_stop);
 462
 463 /**
 464  * drm_sched_start - recover jobs after a reset
 465  *
 466  * @sched: scheduler instance
 467  * @full_recovery: proceed with complete sched restart
 468  *
 469  */
 470 void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
 471 {
 472         struct drm_sched_job *s_job, *tmp;
 473         int r;
 474
 475         /*
 476          * Locking the list is not required here as the sched thread is parked
 477          * so no new jobs are being inserted or removed. Also concurrent
 478          * GPU recovers can't run in parallel.
 479          */
 480         list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
 481                 struct dma_fence *fence = s_job->s_fence->parent;
 482
 483                 atomic_inc(&sched->hw_rq_count);
 484
 485                 if (!full_recovery)
 486                         continue;
 487
 488                 if (fence) {
 489                         r = dma_fence_add_callback(fence, &s_job->cb,
 490                                                    drm_sched_job_done_cb);
 491                         if (r == -ENOENT)
 492                                 drm_sched_job_done(s_job);
 493                         else if (r)
 494                                 DRM_ERROR("fence add callback failed (%d)\n",
 495                                           r);
 496                 } else
 497                         drm_sched_job_done(s_job);
 498         }
 499
 500         if (full_recovery) {
 501                 spin_lock(&sched->job_list_lock);
 502                 drm_sched_start_timeout(sched);
 503                 spin_unlock(&sched->job_list_lock);
 504         }
 505
 506         kthread_unpark(sched->thread);
 507 }
 508 EXPORT_SYMBOL(drm_sched_start);
 509
 510 /**
 511  * drm_sched_resubmit_jobs - helper to relaunch jobs from the pending list
 512  *
 513  * @sched: scheduler instance
 514  *
 515  */
 516 void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
 517 {
 518         drm_sched_resubmit_jobs_ext(sched, INT_MAX);
 519 }
 520 EXPORT_SYMBOL(drm_sched_resubmit_jobs);
 521
 522 /**
 523  * drm_sched_resubmit_jobs_ext - helper to relunch certain number of jobs from mirror ring list
 524  *
 525  * @sched: scheduler instance
 526  * @max: job numbers to relaunch
 527  *
 528  */
 529 void drm_sched_resubmit_jobs_ext(struct drm_gpu_scheduler *sched, int max)
 530 {
 531         struct drm_sched_job *s_job, *tmp;
 532         uint64_t guilty_context;
 533         bool found_guilty = false;
 534         struct dma_fence *fence;
 535         int i = 0;
 536
 537         list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
 538                 struct drm_sched_fence *s_fence = s_job->s_fence;
 539
 540                 if (i >= max)
 541                         break;
 542
 543                 if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
 544                         found_guilty = true;
 545                         guilty_context = s_job->s_fence->scheduled.context;
 546                 }
 547
 548                 if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
 549                         dma_fence_set_error(&s_fence->finished, -ECANCELED);
 550
 551                 dma_fence_put(s_job->s_fence->parent);
 552                 fence = sched->ops->run_job(s_job);
 553                 i++;
 554
 555                 if (IS_ERR_OR_NULL(fence)) {
 556                         if (IS_ERR(fence))
 557                                 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
 558
 559                         s_job->s_fence->parent = NULL;
 560                 } else {
 561                         s_job->s_fence->parent = fence;
 562                 }
 563         }
 564 }
 565 EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
 566
 567 /**
 568  * drm_sched_job_init - init a scheduler job
 569  * @job: scheduler job to init
 570  * @entity: scheduler entity to use
 571  * @owner: job owner for debugging
 572  *
 573  * Refer to drm_sched_entity_push_job() documentation
 574  * for locking considerations.
 575  *
 576  * Drivers must make sure drm_sched_job_cleanup() if this function returns
 577  * successfully, even when @job is aborted before drm_sched_job_arm() is called.
 578  *
 579  * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
 580  * has died, which can mean that there's no valid runqueue for a @entity.
 581  * This function returns -ENOENT in this case (which probably should be -EIO as
 582  * a more meanigful return value).
 583  *
 584  * Returns 0 for success, negative error code otherwise.
 585  */
 586 int drm_sched_job_init(struct drm_sched_job *job,
 587                        struct drm_sched_entity *entity,
 588                        void *owner)
 589 {
 590         drm_sched_entity_select_rq(entity);
 591         if (!entity->rq)
 592                 return -ENOENT;
 593
 594         job->entity = entity;
 595         job->s_fence = drm_sched_fence_alloc(entity, owner);
 596         if (!job->s_fence)
 597                 return -ENOMEM;
 598
 599         INIT_LIST_HEAD(&job->list);
 600
 601         xa_init_flags(&job->dependencies, XA_FLAGS_ALLOC);
 602
 603         return 0;
 604 }
 605 EXPORT_SYMBOL(drm_sched_job_init);
 606
 607 /**
 608  * drm_sched_job_arm - arm a scheduler job for execution
 609  * @job: scheduler job to arm
 610  *
 611  * This arms a scheduler job for execution. Specifically it initializes the
 612  * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
 613  * or other places that need to track the completion of this job.
 614  *
 615  * Refer to drm_sched_entity_push_job() documentation for locking
 616  * considerations.
 617  *
 618  * This can only be called if drm_sched_job_init() succeeded.
 619  */
 620 void drm_sched_job_arm(struct drm_sched_job *job)
 621 {
 622         struct drm_gpu_scheduler *sched;
 623         struct drm_sched_entity *entity = job->entity;
 624
 625         BUG_ON(!entity);
 626
 627         sched = entity->rq->sched;
 628
 629         job->sched = sched;
 630         job->s_priority = entity->rq - sched->sched_rq;
 631         job->id = atomic64_inc_return(&sched->job_id_count);
 632
 633         drm_sched_fence_init(job->s_fence, job->entity);
 634 }
 635 EXPORT_SYMBOL(drm_sched_job_arm);
 636
 637 /**
 638  * drm_sched_job_add_dependency - adds the fence as a job dependency
 639  * @job: scheduler job to add the dependencies to
 640  * @fence: the dma_fence to add to the list of dependencies.
 641  *
 642  * Note that @fence is consumed in both the success and error cases.
 643  *
 644  * Returns:
 645  * 0 on success, or an error on failing to expand the array.
 646  */
 647 int drm_sched_job_add_dependency(struct drm_sched_job *job,
 648                                  struct dma_fence *fence)
 649 {
 650         struct dma_fence *entry;
 651         unsigned long index;
 652         u32 id = 0;
 653         int ret;
 654
 655         if (!fence)
 656                 return 0;
 657
 658         /* Deduplicate if we already depend on a fence from the same context.
 659          * This lets the size of the array of deps scale with the number of
 660          * engines involved, rather than the number of BOs.
 661          */
 662         xa_for_each(&job->dependencies, index, entry) {
 663                 if (entry->context != fence->context)
 664                         continue;
 665
 666                 if (dma_fence_is_later(fence, entry)) {
 667                         dma_fence_put(entry);
 668                         xa_store(&job->dependencies, index, fence, GFP_KERNEL);
 669                 } else {
 670                         dma_fence_put(fence);
 671                 }
 672                 return 0;
 673         }
 674
 675         ret = xa_alloc(&job->dependencies, &id, fence, xa_limit_32b, GFP_KERNEL);
 676         if (ret != 0)
 677                 dma_fence_put(fence);
 678
 679         return ret;
 680 }
 681 EXPORT_SYMBOL(drm_sched_job_add_dependency);
 682
 683 /**
 684  * drm_sched_job_add_implicit_dependencies - adds implicit dependencies as job
 685  *   dependencies
 686  * @job: scheduler job to add the dependencies to
 687  * @obj: the gem object to add new dependencies from.
 688  * @write: whether the job might write the object (so we need to depend on
 689  * shared fences in the reservation object).
 690  *
 691  * This should be called after drm_gem_lock_reservations() on your array of
 692  * GEM objects used in the job but before updating the reservations with your
 693  * own fences.
 694  *
 695  * Returns:
 696  * 0 on success, or an error on failing to expand the array.
 697  */
 698 int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 699                                             struct drm_gem_object *obj,
 700                                             bool write)
 701 {
 702         struct dma_resv_iter cursor;
 703         struct dma_fence *fence;
 704         int ret;
 705
 706         dma_resv_for_each_fence(&cursor, obj->resv, write, fence) {
 707                 ret = drm_sched_job_add_dependency(job, fence);
 708                 if (ret)
 709                         return ret;
 710
 711                 /* Make sure to grab an additional ref on the added fence */
 712                 dma_fence_get(fence);
 713         }
 714         return 0;
 715 }
 716 EXPORT_SYMBOL(drm_sched_job_add_implicit_dependencies);
 717
 718
 719 /**
 720  * drm_sched_job_cleanup - clean up scheduler job resources
 721  * @job: scheduler job to clean up
 722  *
 723  * Cleans up the resources allocated with drm_sched_job_init().
 724  *
 725  * Drivers should call this from their error unwind code if @job is aborted
 726  * before drm_sched_job_arm() is called.
 727  *
 728  * After that point of no return @job is committed to be executed by the
 729  * scheduler, and this function should be called from the
 730  * &drm_sched_backend_ops.free_job callback.
 731  */
 732 void drm_sched_job_cleanup(struct drm_sched_job *job)
 733 {
 734         struct dma_fence *fence;
 735         unsigned long index;
 736
 737         if (kref_read(&job->s_fence->finished.refcount)) {
 738                 /* drm_sched_job_arm() has been called */
 739                 dma_fence_put(&job->s_fence->finished);
 740         } else {
 741                 /* aborted job before committing to run it */
 742                 drm_sched_fence_free(job->s_fence);
 743         }
 744
 745         job->s_fence = NULL;
 746
 747         xa_for_each(&job->dependencies, index, fence) {
 748                 dma_fence_put(fence);
 749         }
 750         xa_destroy(&job->dependencies);
 751
 752 }
 753 EXPORT_SYMBOL(drm_sched_job_cleanup);
 754
 755 /**
 756  * drm_sched_ready - is the scheduler ready
 757  *
 758  * @sched: scheduler instance
 759  *
 760  * Return true if we can push more jobs to the hw, otherwise false.
 761  */
 762 static bool drm_sched_ready(struct drm_gpu_scheduler *sched)
 763 {
 764         return atomic_read(&sched->hw_rq_count) <
 765                 sched->hw_submission_limit;
 766 }
 767
 768 /**
 769  * drm_sched_wakeup - Wake up the scheduler when it is ready
 770  *
 771  * @sched: scheduler instance
 772  *
 773  */
 774 void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
 775 {
 776         if (drm_sched_ready(sched))
 777                 wake_up_interruptible(&sched->wake_up_worker);
 778 }
 779
 780 /**
 781  * drm_sched_select_entity - Select next entity to process
 782  *
 783  * @sched: scheduler instance
 784  *
 785  * Returns the entity to process or NULL if none are found.
 786  */
 787 static struct drm_sched_entity *
 788 drm_sched_select_entity(struct drm_gpu_scheduler *sched)
 789 {
 790         struct drm_sched_entity *entity;
 791         int i;
 792
 793         if (!drm_sched_ready(sched))
 794                 return NULL;
 795
 796         /* Kernel run queue has higher priority than normal run queue*/
 797         for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
 798                 entity = drm_sched_rq_select_entity(&sched->sched_rq[i]);
 799                 if (entity)
 800                         break;
 801         }
 802
 803         return entity;
 804 }
 805
 806 /**
 807  * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
 808  *
 809  * @sched: scheduler instance
 810  *
 811  * Returns the next finished job from the pending list (if there is one)
 812  * ready for it to be destroyed.
 813  */
 814 static struct drm_sched_job *
 815 drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
 816 {
 817         struct drm_sched_job *job, *next;
 818
 819         spin_lock(&sched->job_list_lock);
 820
 821         job = list_first_entry_or_null(&sched->pending_list,
 822                                        struct drm_sched_job, list);
 823
 824         if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
 825                 /* remove job from pending_list */
 826                 list_del_init(&job->list);
 827
 828                 /* cancel this job's TO timer */
 829                 cancel_delayed_work(&sched->work_tdr);
 830                 /* make the scheduled timestamp more accurate */
 831                 next = list_first_entry_or_null(&sched->pending_list,
 832                                                 typeof(*next), list);
 833
 834                 if (next) {
 835                         next->s_fence->scheduled.timestamp =
 836                                 job->s_fence->finished.timestamp;
 837                         /* start TO timer for next job */
 838                         drm_sched_start_timeout(sched);
 839                 }
 840         } else {
 841                 job = NULL;
 842         }
 843
 844         spin_unlock(&sched->job_list_lock);
 845
 846         return job;
 847 }
 848
 849 /**
 850  * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
 851  * @sched_list: list of drm_gpu_schedulers
 852  * @num_sched_list: number of drm_gpu_schedulers in the sched_list
 853  *
 854  * Returns pointer of the sched with the least load or NULL if none of the
 855  * drm_gpu_schedulers are ready
 856  */
 857 struct drm_gpu_scheduler *
 858 drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
 859                      unsigned int num_sched_list)
 860 {
 861         struct drm_gpu_scheduler *sched, *picked_sched = NULL;
 862         int i;
 863         unsigned int min_score = UINT_MAX, num_score;
 864
 865         for (i = 0; i < num_sched_list; ++i) {
 866                 sched = sched_list[i];
 867
 868                 if (!sched->ready) {
 869                         DRM_WARN("scheduler %s is not ready, skipping",
 870                                  sched->name);
 871                         continue;
 872                 }
 873
 874                 num_score = atomic_read(sched->score);
 875                 if (num_score < min_score) {
 876                         min_score = num_score;
 877                         picked_sched = sched;
 878                 }
 879         }
 880
 881         return picked_sched;
 882 }
 883 EXPORT_SYMBOL(drm_sched_pick_best);
 884
 885 /**
 886  * drm_sched_blocked - check if the scheduler is blocked
 887  *
 888  * @sched: scheduler instance
 889  *
 890  * Returns true if blocked, otherwise false.
 891  */
 892 static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
 893 {
 894         if (kthread_should_park()) {
 895                 kthread_parkme();
 896                 return true;
 897         }
 898
 899         return false;
 900 }
 901
 902 /**
 903  * drm_sched_main - main scheduler thread
 904  *
 905  * @param: scheduler instance
 906  *
 907  * Returns 0.
 908  */
 909 static int drm_sched_main(void *param)
 910 {
 911         struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
 912         int r;
 913
 914         sched_set_fifo_low(current);
 915
 916         while (!kthread_should_stop()) {
 917                 struct drm_sched_entity *entity = NULL;
 918                 struct drm_sched_fence *s_fence;
 919                 struct drm_sched_job *sched_job;
 920                 struct dma_fence *fence;
 921                 struct drm_sched_job *cleanup_job = NULL;
 922
 923                 wait_event_interruptible(sched->wake_up_worker,
 924                                          (cleanup_job = drm_sched_get_cleanup_job(sched)) ||
 925                                          (!drm_sched_blocked(sched) &&
 926                                           (entity = drm_sched_select_entity(sched))) ||
 927                                          kthread_should_stop());
 928
 929                 if (cleanup_job)
 930                         sched->ops->free_job(cleanup_job);
 931
 932                 if (!entity)
 933                         continue;
 934
 935                 sched_job = drm_sched_entity_pop_job(entity);
 936
 937                 if (!sched_job) {
 938                         complete(&entity->entity_idle);
 939                         continue;
 940                 }
 941
 942                 s_fence = sched_job->s_fence;
 943
 944                 atomic_inc(&sched->hw_rq_count);
 945                 drm_sched_job_begin(sched_job);
 946
 947                 trace_drm_run_job(sched_job, entity);
 948                 fence = sched->ops->run_job(sched_job);
 949                 complete(&entity->entity_idle);
 950                 drm_sched_fence_scheduled(s_fence);
 951
 952                 if (!IS_ERR_OR_NULL(fence)) {
 953                         s_fence->parent = dma_fence_get(fence);
 954                         r = dma_fence_add_callback(fence, &sched_job->cb,
 955                                                    drm_sched_job_done_cb);
 956                         if (r == -ENOENT)
 957                                 drm_sched_job_done(sched_job);
 958                         else if (r)
 959                                 DRM_ERROR("fence add callback failed (%d)\n",
 960                                           r);
 961                         dma_fence_put(fence);
 962                 } else {
 963                         if (IS_ERR(fence))
 964                                 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
 965
 966                         drm_sched_job_done(sched_job);
 967                 }
 968
 969                 wake_up(&sched->job_scheduled);
 970         }
 971         return 0;
 972 }
 973
 974 /**
 975  * drm_sched_init - Init a gpu scheduler instance
 976  *
 977  * @sched: scheduler instance
 978  * @ops: backend operations for this scheduler
 979  * @hw_submission: number of hw submissions that can be in flight
 980  * @hang_limit: number of times to allow a job to hang before dropping it
 981  * @timeout: timeout value in jiffies for the scheduler
 982  * @timeout_wq: workqueue to use for timeout work. If NULL, the system_wq is
 983  *              used
 984  * @score: optional score atomic shared with other schedulers
 985  * @name: name used for debugging
 986  *
 987  * Return 0 on success, otherwise error code.
 988  */
 989 int drm_sched_init(struct drm_gpu_scheduler *sched,
 990                    const struct drm_sched_backend_ops *ops,
 991                    unsigned hw_submission, unsigned hang_limit,
 992                    long timeout, struct workqueue_struct *timeout_wq,
 993                    atomic_t *score, const char *name)
 994 {
 995         int i, ret;
 996         sched->ops = ops;
 997         sched->hw_submission_limit = hw_submission;
 998         sched->name = name;
 999         sched->timeout = timeout;
1000         sched->timeout_wq = timeout_wq ? : system_wq;
1001         sched->hang_limit = hang_limit;
1002         sched->score = score ? score : &sched->_score;
1003         for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; i++)
1004                 drm_sched_rq_init(sched, &sched->sched_rq[i]);
1005
1006         init_waitqueue_head(&sched->wake_up_worker);
1007         init_waitqueue_head(&sched->job_scheduled);
1008         INIT_LIST_HEAD(&sched->pending_list);
1009         spin_lock_init(&sched->job_list_lock);
1010         atomic_set(&sched->hw_rq_count, 0);
1011         INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
1012         atomic_set(&sched->_score, 0);
1013         atomic64_set(&sched->job_id_count, 0);
1014
1015         /* Each scheduler will run on a seperate kernel thread */
1016         sched->thread = kthread_run(drm_sched_main, sched, sched->name);
1017         if (IS_ERR(sched->thread)) {
1018                 ret = PTR_ERR(sched->thread);
1019                 sched->thread = NULL;
1020                 DRM_ERROR("Failed to create scheduler for %s.\n", name);
1021                 return ret;
1022         }
1023
1024         sched->ready = true;
1025         return 0;
1026 }
1027 EXPORT_SYMBOL(drm_sched_init);
1028
1029 /**
1030  * drm_sched_fini - Destroy a gpu scheduler
1031  *
1032  * @sched: scheduler instance
1033  *
1034  * Tears down and cleans up the scheduler.
1035  */
1036 void drm_sched_fini(struct drm_gpu_scheduler *sched)
1037 {
1038         struct drm_sched_entity *s_entity;
1039         int i;
1040
1041         if (sched->thread)
1042                 kthread_stop(sched->thread);
1043
1044         for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
1045                 struct drm_sched_rq *rq = &sched->sched_rq[i];
1046
1047                 if (!rq)
1048                         continue;
1049
1050                 spin_lock(&rq->lock);
1051                 list_for_each_entry(s_entity, &rq->entities, list)
1052                         /*
1053                          * Prevents reinsertion and marks job_queue as idle,
1054                          * it will removed from rq in drm_sched_entity_fini
1055                          * eventually
1056                          */
1057                         s_entity->stopped = true;
1058                 spin_unlock(&rq->lock);
1059
1060         }
1061
1062         /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
1063         wake_up_all(&sched->job_scheduled);
1064
1065         /* Confirm no work left behind accessing device structures */
1066         cancel_delayed_work_sync(&sched->work_tdr);
1067
1068         sched->ready = false;
1069 }
1070 EXPORT_SYMBOL(drm_sched_fini);
1071
1072 /**
1073  * drm_sched_increase_karma_ext - Update sched_entity guilty flag
1074  *
1075  * @bad: The job guilty of time out
1076  * @type: type for increase/reset karma
1077  *
1078  */
1079 void drm_sched_increase_karma_ext(struct drm_sched_job *bad, int type)
1080 {
1081         int i;
1082         struct drm_sched_entity *tmp;
1083         struct drm_sched_entity *entity;
1084         struct drm_gpu_scheduler *sched = bad->sched;
1085
1086         /* don't change @bad's karma if it's from KERNEL RQ,
1087          * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
1088          * corrupt but keep in mind that kernel jobs always considered good.
1089          */
1090         if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
1091                 if (type == 0)
1092                         atomic_set(&bad->karma, 0);
1093                 else if (type == 1)
1094                         atomic_inc(&bad->karma);
1095
1096                 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
1097                      i++) {
1098                         struct drm_sched_rq *rq = &sched->sched_rq[i];
1099
1100                         spin_lock(&rq->lock);
1101                         list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
1102                                 if (bad->s_fence->scheduled.context ==
1103                                     entity->fence_context) {
1104                                         if (entity->guilty)
1105                                                 atomic_set(entity->guilty, type);
1106                                         break;
1107                                 }
1108                         }
1109                         spin_unlock(&rq->lock);
1110                         if (&entity->list != &rq->entities)
1111                                 break;
1112                 }
1113         }
1114 }
1115 EXPORT_SYMBOL(drm_sched_increase_karma_ext);