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                         dma_fence_put(s_job->s_fence->parent);
 423                         s_job->s_fence->parent = NULL;
 424                         atomic_dec(&sched->hw_rq_count);
 425                 } else {
 426                         /*
 427                          * remove job from pending_list.
 428                          * Locking here is for concurrent resume timeout
 429                          */
 430                         spin_lock(&sched->job_list_lock);
 431                         list_del_init(&s_job->list);
 432                         spin_unlock(&sched->job_list_lock);
 433
 434                         /*
 435                          * Wait for job's HW fence callback to finish using s_job
 436                          * before releasing it.
 437                          *
 438                          * Job is still alive so fence refcount at least 1
 439                          */
 440                         dma_fence_wait(&s_job->s_fence->finished, false);
 441
 442                         /*
 443                          * We must keep bad job alive for later use during
 444                          * recovery by some of the drivers but leave a hint
 445                          * that the guilty job must be released.
 446                          */
 447                         if (bad != s_job)
 448                                 sched->ops->free_job(s_job);
 449                         else
 450                                 sched->free_guilty = true;
 451                 }
 452         }
 453
 454         /*
 455          * Stop pending timer in flight as we rearm it in  drm_sched_start. This
 456          * avoids the pending timeout work in progress to fire right away after
 457          * this TDR finished and before the newly restarted jobs had a
 458          * chance to complete.
 459          */
 460         cancel_delayed_work(&sched->work_tdr);
 461 }
 462
 463 EXPORT_SYMBOL(drm_sched_stop);
 464
 465 /**
 466  * drm_sched_start - recover jobs after a reset
 467  *
 468  * @sched: scheduler instance
 469  * @full_recovery: proceed with complete sched restart
 470  *
 471  */
 472 void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
 473 {
 474         struct drm_sched_job *s_job, *tmp;
 475         int r;
 476
 477         /*
 478          * Locking the list is not required here as the sched thread is parked
 479          * so no new jobs are being inserted or removed. Also concurrent
 480          * GPU recovers can't run in parallel.
 481          */
 482         list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
 483                 struct dma_fence *fence = s_job->s_fence->parent;
 484
 485                 atomic_inc(&sched->hw_rq_count);
 486
 487                 if (!full_recovery)
 488                         continue;
 489
 490                 if (fence) {
 491                         r = dma_fence_add_callback(fence, &s_job->cb,
 492                                                    drm_sched_job_done_cb);
 493                         if (r == -ENOENT)
 494                                 drm_sched_job_done(s_job);
 495                         else if (r)
 496                                 DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
 497                                           r);
 498                 } else
 499                         drm_sched_job_done(s_job);
 500         }
 501
 502         if (full_recovery) {
 503                 spin_lock(&sched->job_list_lock);
 504                 drm_sched_start_timeout(sched);
 505                 spin_unlock(&sched->job_list_lock);
 506         }
 507
 508         kthread_unpark(sched->thread);
 509 }
 510 EXPORT_SYMBOL(drm_sched_start);
 511
 512 /**
 513  * drm_sched_resubmit_jobs - helper to relaunch jobs from the pending list
 514  *
 515  * @sched: scheduler instance
 516  *
 517  */
 518 void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
 519 {
 520         drm_sched_resubmit_jobs_ext(sched, INT_MAX);
 521 }
 522 EXPORT_SYMBOL(drm_sched_resubmit_jobs);
 523
 524 /**
 525  * drm_sched_resubmit_jobs_ext - helper to relunch certain number of jobs from mirror ring list
 526  *
 527  * @sched: scheduler instance
 528  * @max: job numbers to relaunch
 529  *
 530  */
 531 void drm_sched_resubmit_jobs_ext(struct drm_gpu_scheduler *sched, int max)
 532 {
 533         struct drm_sched_job *s_job, *tmp;
 534         uint64_t guilty_context;
 535         bool found_guilty = false;
 536         struct dma_fence *fence;
 537         int i = 0;
 538
 539         list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
 540                 struct drm_sched_fence *s_fence = s_job->s_fence;
 541
 542                 if (i >= max)
 543                         break;
 544
 545                 if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
 546                         found_guilty = true;
 547                         guilty_context = s_job->s_fence->scheduled.context;
 548                 }
 549
 550                 if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
 551                         dma_fence_set_error(&s_fence->finished, -ECANCELED);
 552
 553                 fence = sched->ops->run_job(s_job);
 554                 i++;
 555
 556                 if (IS_ERR_OR_NULL(fence)) {
 557                         if (IS_ERR(fence))
 558                                 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
 559
 560                         s_job->s_fence->parent = NULL;
 561                 } else {
 562
 563                         s_job->s_fence->parent = dma_fence_get(fence);
 564
 565                         /* Drop for orignal kref_init */
 566                         dma_fence_put(fence);
 567                 }
 568         }
 569 }
 570 EXPORT_SYMBOL(drm_sched_resubmit_jobs_ext);
 571
 572 /**
 573  * drm_sched_job_init - init a scheduler job
 574  * @job: scheduler job to init
 575  * @entity: scheduler entity to use
 576  * @owner: job owner for debugging
 577  *
 578  * Refer to drm_sched_entity_push_job() documentation
 579  * for locking considerations.
 580  *
 581  * Drivers must make sure drm_sched_job_cleanup() if this function returns
 582  * successfully, even when @job is aborted before drm_sched_job_arm() is called.
 583  *
 584  * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
 585  * has died, which can mean that there's no valid runqueue for a @entity.
 586  * This function returns -ENOENT in this case (which probably should be -EIO as
 587  * a more meanigful return value).
 588  *
 589  * Returns 0 for success, negative error code otherwise.
 590  */
 591 int drm_sched_job_init(struct drm_sched_job *job,
 592                        struct drm_sched_entity *entity,
 593                        void *owner)
 594 {
 595         drm_sched_entity_select_rq(entity);
 596         if (!entity->rq)
 597                 return -ENOENT;
 598
 599         job->entity = entity;
 600         job->s_fence = drm_sched_fence_alloc(entity, owner);
 601         if (!job->s_fence)
 602                 return -ENOMEM;
 603
 604         INIT_LIST_HEAD(&job->list);
 605
 606         xa_init_flags(&job->dependencies, XA_FLAGS_ALLOC);
 607
 608         return 0;
 609 }
 610 EXPORT_SYMBOL(drm_sched_job_init);
 611
 612 /**
 613  * drm_sched_job_arm - arm a scheduler job for execution
 614  * @job: scheduler job to arm
 615  *
 616  * This arms a scheduler job for execution. Specifically it initializes the
 617  * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
 618  * or other places that need to track the completion of this job.
 619  *
 620  * Refer to drm_sched_entity_push_job() documentation for locking
 621  * considerations.
 622  *
 623  * This can only be called if drm_sched_job_init() succeeded.
 624  */
 625 void drm_sched_job_arm(struct drm_sched_job *job)
 626 {
 627         struct drm_gpu_scheduler *sched;
 628         struct drm_sched_entity *entity = job->entity;
 629
 630         BUG_ON(!entity);
 631
 632         sched = entity->rq->sched;
 633
 634         job->sched = sched;
 635         job->s_priority = entity->rq - sched->sched_rq;
 636         job->id = atomic64_inc_return(&sched->job_id_count);
 637
 638         drm_sched_fence_init(job->s_fence, job->entity);
 639 }
 640 EXPORT_SYMBOL(drm_sched_job_arm);
 641
 642 /**
 643  * drm_sched_job_add_dependency - adds the fence as a job dependency
 644  * @job: scheduler job to add the dependencies to
 645  * @fence: the dma_fence to add to the list of dependencies.
 646  *
 647  * Note that @fence is consumed in both the success and error cases.
 648  *
 649  * Returns:
 650  * 0 on success, or an error on failing to expand the array.
 651  */
 652 int drm_sched_job_add_dependency(struct drm_sched_job *job,
 653                                  struct dma_fence *fence)
 654 {
 655         struct dma_fence *entry;
 656         unsigned long index;
 657         u32 id = 0;
 658         int ret;
 659
 660         if (!fence)
 661                 return 0;
 662
 663         /* Deduplicate if we already depend on a fence from the same context.
 664          * This lets the size of the array of deps scale with the number of
 665          * engines involved, rather than the number of BOs.
 666          */
 667         xa_for_each(&job->dependencies, index, entry) {
 668                 if (entry->context != fence->context)
 669                         continue;
 670
 671                 if (dma_fence_is_later(fence, entry)) {
 672                         dma_fence_put(entry);
 673                         xa_store(&job->dependencies, index, fence, GFP_KERNEL);
 674                 } else {
 675                         dma_fence_put(fence);
 676                 }
 677                 return 0;
 678         }
 679
 680         ret = xa_alloc(&job->dependencies, &id, fence, xa_limit_32b, GFP_KERNEL);
 681         if (ret != 0)
 682                 dma_fence_put(fence);
 683
 684         return ret;
 685 }
 686 EXPORT_SYMBOL(drm_sched_job_add_dependency);
 687
 688 /**
 689  * drm_sched_job_add_implicit_dependencies - adds implicit dependencies as job
 690  *   dependencies
 691  * @job: scheduler job to add the dependencies to
 692  * @obj: the gem object to add new dependencies from.
 693  * @write: whether the job might write the object (so we need to depend on
 694  * shared fences in the reservation object).
 695  *
 696  * This should be called after drm_gem_lock_reservations() on your array of
 697  * GEM objects used in the job but before updating the reservations with your
 698  * own fences.
 699  *
 700  * Returns:
 701  * 0 on success, or an error on failing to expand the array.
 702  */
 703 int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 704                                             struct drm_gem_object *obj,
 705                                             bool write)
 706 {
 707         struct dma_resv_iter cursor;
 708         struct dma_fence *fence;
 709         int ret;
 710
 711         dma_resv_assert_held(obj->resv);
 712
 713         dma_resv_for_each_fence(&cursor, obj->resv, dma_resv_usage_rw(write),
 714                                 fence) {
 715                 /* Make sure to grab an additional ref on the added fence */
 716                 dma_fence_get(fence);
 717                 ret = drm_sched_job_add_dependency(job, fence);
 718                 if (ret) {
 719                         dma_fence_put(fence);
 720                         return ret;
 721                 }
 722         }
 723         return 0;
 724 }
 725 EXPORT_SYMBOL(drm_sched_job_add_implicit_dependencies);
 726
 727
 728 /**
 729  * drm_sched_job_cleanup - clean up scheduler job resources
 730  * @job: scheduler job to clean up
 731  *
 732  * Cleans up the resources allocated with drm_sched_job_init().
 733  *
 734  * Drivers should call this from their error unwind code if @job is aborted
 735  * before drm_sched_job_arm() is called.
 736  *
 737  * After that point of no return @job is committed to be executed by the
 738  * scheduler, and this function should be called from the
 739  * &drm_sched_backend_ops.free_job callback.
 740  */
 741 void drm_sched_job_cleanup(struct drm_sched_job *job)
 742 {
 743         struct dma_fence *fence;
 744         unsigned long index;
 745
 746         if (kref_read(&job->s_fence->finished.refcount)) {
 747                 /* drm_sched_job_arm() has been called */
 748                 dma_fence_put(&job->s_fence->finished);
 749         } else {
 750                 /* aborted job before committing to run it */
 751                 drm_sched_fence_free(job->s_fence);
 752         }
 753
 754         job->s_fence = NULL;
 755
 756         xa_for_each(&job->dependencies, index, fence) {
 757                 dma_fence_put(fence);
 758         }
 759         xa_destroy(&job->dependencies);
 760
 761 }
 762 EXPORT_SYMBOL(drm_sched_job_cleanup);
 763
 764 /**
 765  * drm_sched_ready - is the scheduler ready
 766  *
 767  * @sched: scheduler instance
 768  *
 769  * Return true if we can push more jobs to the hw, otherwise false.
 770  */
 771 static bool drm_sched_ready(struct drm_gpu_scheduler *sched)
 772 {
 773         return atomic_read(&sched->hw_rq_count) <
 774                 sched->hw_submission_limit;
 775 }
 776
 777 /**
 778  * drm_sched_wakeup - Wake up the scheduler when it is ready
 779  *
 780  * @sched: scheduler instance
 781  *
 782  */
 783 void drm_sched_wakeup(struct drm_gpu_scheduler *sched)
 784 {
 785         if (drm_sched_ready(sched))
 786                 wake_up_interruptible(&sched->wake_up_worker);
 787 }
 788
 789 /**
 790  * drm_sched_select_entity - Select next entity to process
 791  *
 792  * @sched: scheduler instance
 793  *
 794  * Returns the entity to process or NULL if none are found.
 795  */
 796 static struct drm_sched_entity *
 797 drm_sched_select_entity(struct drm_gpu_scheduler *sched)
 798 {
 799         struct drm_sched_entity *entity;
 800         int i;
 801
 802         if (!drm_sched_ready(sched))
 803                 return NULL;
 804
 805         /* Kernel run queue has higher priority than normal run queue*/
 806         for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
 807                 entity = drm_sched_rq_select_entity(&sched->sched_rq[i]);
 808                 if (entity)
 809                         break;
 810         }
 811
 812         return entity;
 813 }
 814
 815 /**
 816  * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
 817  *
 818  * @sched: scheduler instance
 819  *
 820  * Returns the next finished job from the pending list (if there is one)
 821  * ready for it to be destroyed.
 822  */
 823 static struct drm_sched_job *
 824 drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
 825 {
 826         struct drm_sched_job *job, *next;
 827
 828         spin_lock(&sched->job_list_lock);
 829
 830         job = list_first_entry_or_null(&sched->pending_list,
 831                                        struct drm_sched_job, list);
 832
 833         if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
 834                 /* remove job from pending_list */
 835                 list_del_init(&job->list);
 836
 837                 /* cancel this job's TO timer */
 838                 cancel_delayed_work(&sched->work_tdr);
 839                 /* make the scheduled timestamp more accurate */
 840                 next = list_first_entry_or_null(&sched->pending_list,
 841                                                 typeof(*next), list);
 842
 843                 if (next) {
 844                         next->s_fence->scheduled.timestamp =
 845                                 job->s_fence->finished.timestamp;
 846                         /* start TO timer for next job */
 847                         drm_sched_start_timeout(sched);
 848                 }
 849         } else {
 850                 job = NULL;
 851         }
 852
 853         spin_unlock(&sched->job_list_lock);
 854
 855         return job;
 856 }
 857
 858 /**
 859  * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
 860  * @sched_list: list of drm_gpu_schedulers
 861  * @num_sched_list: number of drm_gpu_schedulers in the sched_list
 862  *
 863  * Returns pointer of the sched with the least load or NULL if none of the
 864  * drm_gpu_schedulers are ready
 865  */
 866 struct drm_gpu_scheduler *
 867 drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
 868                      unsigned int num_sched_list)
 869 {
 870         struct drm_gpu_scheduler *sched, *picked_sched = NULL;
 871         int i;
 872         unsigned int min_score = UINT_MAX, num_score;
 873
 874         for (i = 0; i < num_sched_list; ++i) {
 875                 sched = sched_list[i];
 876
 877                 if (!sched->ready) {
 878                         DRM_WARN("scheduler %s is not ready, skipping",
 879                                  sched->name);
 880                         continue;
 881                 }
 882
 883                 num_score = atomic_read(sched->score);
 884                 if (num_score < min_score) {
 885                         min_score = num_score;
 886                         picked_sched = sched;
 887                 }
 888         }
 889
 890         return picked_sched;
 891 }
 892 EXPORT_SYMBOL(drm_sched_pick_best);
 893
 894 /**
 895  * drm_sched_blocked - check if the scheduler is blocked
 896  *
 897  * @sched: scheduler instance
 898  *
 899  * Returns true if blocked, otherwise false.
 900  */
 901 static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
 902 {
 903         if (kthread_should_park()) {
 904                 kthread_parkme();
 905                 return true;
 906         }
 907
 908         return false;
 909 }
 910
 911 /**
 912  * drm_sched_main - main scheduler thread
 913  *
 914  * @param: scheduler instance
 915  *
 916  * Returns 0.
 917  */
 918 static int drm_sched_main(void *param)
 919 {
 920         struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
 921         int r;
 922
 923         sched_set_fifo_low(current);
 924
 925         while (!kthread_should_stop()) {
 926                 struct drm_sched_entity *entity = NULL;
 927                 struct drm_sched_fence *s_fence;
 928                 struct drm_sched_job *sched_job;
 929                 struct dma_fence *fence;
 930                 struct drm_sched_job *cleanup_job = NULL;
 931
 932                 wait_event_interruptible(sched->wake_up_worker,
 933                                          (cleanup_job = drm_sched_get_cleanup_job(sched)) ||
 934                                          (!drm_sched_blocked(sched) &&
 935                                           (entity = drm_sched_select_entity(sched))) ||
 936                                          kthread_should_stop());
 937
 938                 if (cleanup_job)
 939                         sched->ops->free_job(cleanup_job);
 940
 941                 if (!entity)
 942                         continue;
 943
 944                 sched_job = drm_sched_entity_pop_job(entity);
 945
 946                 if (!sched_job) {
 947                         complete(&entity->entity_idle);
 948                         continue;
 949                 }
 950
 951                 s_fence = sched_job->s_fence;
 952
 953                 atomic_inc(&sched->hw_rq_count);
 954                 drm_sched_job_begin(sched_job);
 955
 956                 trace_drm_run_job(sched_job, entity);
 957                 fence = sched->ops->run_job(sched_job);
 958                 complete(&entity->entity_idle);
 959                 drm_sched_fence_scheduled(s_fence);
 960
 961                 if (!IS_ERR_OR_NULL(fence)) {
 962                         s_fence->parent = dma_fence_get(fence);
 963                         /* Drop for original kref_init of the fence */
 964                         dma_fence_put(fence);
 965
 966                         r = dma_fence_add_callback(fence, &sched_job->cb,
 967                                                    drm_sched_job_done_cb);
 968                         if (r == -ENOENT)
 969                                 drm_sched_job_done(sched_job);
 970                         else if (r)
 971                                 DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
 972                                           r);
 973                 } else {
 974                         if (IS_ERR(fence))
 975                                 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
 976
 977                         drm_sched_job_done(sched_job);
 978                 }
 979
 980                 wake_up(&sched->job_scheduled);
 981         }
 982         return 0;
 983 }
 984
 985 /**
 986  * drm_sched_init - Init a gpu scheduler instance
 987  *
 988  * @sched: scheduler instance
 989  * @ops: backend operations for this scheduler
 990  * @hw_submission: number of hw submissions that can be in flight
 991  * @hang_limit: number of times to allow a job to hang before dropping it
 992  * @timeout: timeout value in jiffies for the scheduler
 993  * @timeout_wq: workqueue to use for timeout work. If NULL, the system_wq is
 994  *              used
 995  * @score: optional score atomic shared with other schedulers
 996  * @name: name used for debugging
 997  *
 998  * Return 0 on success, otherwise error code.
 999  */
1000 int drm_sched_init(struct drm_gpu_scheduler *sched,
1001                    const struct drm_sched_backend_ops *ops,
1002                    unsigned hw_submission, unsigned hang_limit,
1003                    long timeout, struct workqueue_struct *timeout_wq,
1004                    atomic_t *score, const char *name, struct device *dev)
1005 {
1006         int i, ret;
1007         sched->ops = ops;
1008         sched->hw_submission_limit = hw_submission;
1009         sched->name = name;
1010         sched->timeout = timeout;
1011         sched->timeout_wq = timeout_wq ? : system_wq;
1012         sched->hang_limit = hang_limit;
1013         sched->score = score ? score : &sched->_score;
1014         sched->dev = dev;
1015         for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; i++)
1016                 drm_sched_rq_init(sched, &sched->sched_rq[i]);
1017
1018         init_waitqueue_head(&sched->wake_up_worker);
1019         init_waitqueue_head(&sched->job_scheduled);
1020         INIT_LIST_HEAD(&sched->pending_list);
1021         spin_lock_init(&sched->job_list_lock);
1022         atomic_set(&sched->hw_rq_count, 0);
1023         INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
1024         atomic_set(&sched->_score, 0);
1025         atomic64_set(&sched->job_id_count, 0);
1026
1027         /* Each scheduler will run on a seperate kernel thread */
1028         sched->thread = kthread_run(drm_sched_main, sched, sched->name);
1029         if (IS_ERR(sched->thread)) {
1030                 ret = PTR_ERR(sched->thread);
1031                 sched->thread = NULL;
1032                 DRM_DEV_ERROR(sched->dev, "Failed to create scheduler for %s.\n", name);
1033                 return ret;
1034         }
1035
1036         sched->ready = true;
1037         return 0;
1038 }
1039 EXPORT_SYMBOL(drm_sched_init);
1040
1041 /**
1042  * drm_sched_fini - Destroy a gpu scheduler
1043  *
1044  * @sched: scheduler instance
1045  *
1046  * Tears down and cleans up the scheduler.
1047  */
1048 void drm_sched_fini(struct drm_gpu_scheduler *sched)
1049 {
1050         struct drm_sched_entity *s_entity;
1051         int i;
1052
1053         if (sched->thread)
1054                 kthread_stop(sched->thread);
1055
1056         for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
1057                 struct drm_sched_rq *rq = &sched->sched_rq[i];
1058
1059                 if (!rq)
1060                         continue;
1061
1062                 spin_lock(&rq->lock);
1063                 list_for_each_entry(s_entity, &rq->entities, list)
1064                         /*
1065                          * Prevents reinsertion and marks job_queue as idle,
1066                          * it will removed from rq in drm_sched_entity_fini
1067                          * eventually
1068                          */
1069                         s_entity->stopped = true;
1070                 spin_unlock(&rq->lock);
1071
1072         }
1073
1074         /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
1075         wake_up_all(&sched->job_scheduled);
1076
1077         /* Confirm no work left behind accessing device structures */
1078         cancel_delayed_work_sync(&sched->work_tdr);
1079
1080         sched->ready = false;
1081 }
1082 EXPORT_SYMBOL(drm_sched_fini);
1083
1084 /**
1085  * drm_sched_increase_karma_ext - Update sched_entity guilty flag
1086  *
1087  * @bad: The job guilty of time out
1088  * @type: type for increase/reset karma
1089  *
1090  */
1091 void drm_sched_increase_karma_ext(struct drm_sched_job *bad, int type)
1092 {
1093         int i;
1094         struct drm_sched_entity *tmp;
1095         struct drm_sched_entity *entity;
1096         struct drm_gpu_scheduler *sched = bad->sched;
1097
1098         /* don't change @bad's karma if it's from KERNEL RQ,
1099          * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
1100          * corrupt but keep in mind that kernel jobs always considered good.
1101          */
1102         if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
1103                 if (type == 0)
1104                         atomic_set(&bad->karma, 0);
1105                 else if (type == 1)
1106                         atomic_inc(&bad->karma);
1107
1108                 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
1109                      i++) {
1110                         struct drm_sched_rq *rq = &sched->sched_rq[i];
1111
1112                         spin_lock(&rq->lock);
1113                         list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
1114                                 if (bad->s_fence->scheduled.context ==
1115                                     entity->fence_context) {
1116                                         if (entity->guilty)
1117                                                 atomic_set(entity->guilty, type);
1118                                         break;
1119                                 }
1120                         }
1121                         spin_unlock(&rq->lock);
1122                         if (&entity->list != &rq->entities)
1123                                 break;
1124                 }
1125         }
1126 }
1127 EXPORT_SYMBOL(drm_sched_increase_karma_ext);