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  * Note that once a job was taken from the entities queue and pushed to the
  47  * hardware, i.e. the pending queue, the entity must not be referenced anymore
  48  * through the jobs entity pointer.
  49  */
  50
  51 #include <linux/kthread.h>
  52 #include <linux/wait.h>
  53 #include <linux/sched.h>
  54 #include <linux/completion.h>
  55 #include <linux/dma-resv.h>
  56 #include <uapi/linux/sched/types.h>
  57
  58 #include <drm/drm_print.h>
  59 #include <drm/drm_gem.h>
  60 #include <drm/drm_syncobj.h>
  61 #include <drm/gpu_scheduler.h>
  62 #include <drm/spsc_queue.h>
  63
  64 #define CREATE_TRACE_POINTS
  65 #include "gpu_scheduler_trace.h"
  66
  67 #define to_drm_sched_job(sched_job)             \
  68                 container_of((sched_job), struct drm_sched_job, queue_node)
  69
  70 int drm_sched_policy = DRM_SCHED_POLICY_FIFO;
  71
  72 /**
  73  * DOC: sched_policy (int)
  74  * Used to override default entities scheduling policy in a run queue.
  75  */
  76 MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO (default).");
  77 module_param_named(sched_policy, drm_sched_policy, int, 0444);
  78
  79 static __always_inline bool drm_sched_entity_compare_before(struct rb_node *a,
  80                                                             const struct rb_node *b)
  81 {
  82         struct drm_sched_entity *ent_a =  rb_entry((a), struct drm_sched_entity, rb_tree_node);
  83         struct drm_sched_entity *ent_b =  rb_entry((b), struct drm_sched_entity, rb_tree_node);
  84
  85         return ktime_before(ent_a->oldest_job_waiting, ent_b->oldest_job_waiting);
  86 }
  87
  88 static inline void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity)
  89 {
  90         struct drm_sched_rq *rq = entity->rq;
  91
  92         if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
  93                 rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
  94                 RB_CLEAR_NODE(&entity->rb_tree_node);
  95         }
  96 }
  97
  98 void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts)
  99 {
 100         /*
 101          * Both locks need to be grabbed, one to protect from entity->rq change
 102          * for entity from within concurrent drm_sched_entity_select_rq and the
 103          * other to update the rb tree structure.
 104          */
 105         spin_lock(&entity->rq_lock);
 106         spin_lock(&entity->rq->lock);
 107
 108         drm_sched_rq_remove_fifo_locked(entity);
 109
 110         entity->oldest_job_waiting = ts;
 111
 112         rb_add_cached(&entity->rb_tree_node, &entity->rq->rb_tree_root,
 113                       drm_sched_entity_compare_before);
 114
 115         spin_unlock(&entity->rq->lock);
 116         spin_unlock(&entity->rq_lock);
 117 }
 118
 119 /**
 120  * drm_sched_rq_init - initialize a given run queue struct
 121  *
 122  * @sched: scheduler instance to associate with this run queue
 123  * @rq: scheduler run queue
 124  *
 125  * Initializes a scheduler runqueue.
 126  */
 127 static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
 128                               struct drm_sched_rq *rq)
 129 {
 130         spin_lock_init(&rq->lock);
 131         INIT_LIST_HEAD(&rq->entities);
 132         rq->rb_tree_root = RB_ROOT_CACHED;
 133         rq->current_entity = NULL;
 134         rq->sched = sched;
 135 }
 136
 137 /**
 138  * drm_sched_rq_add_entity - add an entity
 139  *
 140  * @rq: scheduler run queue
 141  * @entity: scheduler entity
 142  *
 143  * Adds a scheduler entity to the run queue.
 144  */
 145 void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
 146                              struct drm_sched_entity *entity)
 147 {
 148         if (!list_empty(&entity->list))
 149                 return;
 150
 151         spin_lock(&rq->lock);
 152
 153         atomic_inc(rq->sched->score);
 154         list_add_tail(&entity->list, &rq->entities);
 155
 156         spin_unlock(&rq->lock);
 157 }
 158
 159 /**
 160  * drm_sched_rq_remove_entity - remove an entity
 161  *
 162  * @rq: scheduler run queue
 163  * @entity: scheduler entity
 164  *
 165  * Removes a scheduler entity from the run queue.
 166  */
 167 void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
 168                                 struct drm_sched_entity *entity)
 169 {
 170         if (list_empty(&entity->list))
 171                 return;
 172
 173         spin_lock(&rq->lock);
 174
 175         atomic_dec(rq->sched->score);
 176         list_del_init(&entity->list);
 177
 178         if (rq->current_entity == entity)
 179                 rq->current_entity = NULL;
 180
 181         if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
 182                 drm_sched_rq_remove_fifo_locked(entity);
 183
 184         spin_unlock(&rq->lock);
 185 }
 186
 187 /**
 188  * drm_sched_rq_select_entity_rr - Select an entity which could provide a job to run
 189  *
 190  * @rq: scheduler run queue to check.
 191  *
 192  * Try to find a ready entity, returns NULL if none found.
 193  */
 194 static struct drm_sched_entity *
 195 drm_sched_rq_select_entity_rr(struct drm_sched_rq *rq)
 196 {
 197         struct drm_sched_entity *entity;
 198
 199         spin_lock(&rq->lock);
 200
 201         entity = rq->current_entity;
 202         if (entity) {
 203                 list_for_each_entry_continue(entity, &rq->entities, list) {
 204                         if (drm_sched_entity_is_ready(entity)) {
 205                                 rq->current_entity = entity;
 206                                 reinit_completion(&entity->entity_idle);
 207                                 spin_unlock(&rq->lock);
 208                                 return entity;
 209                         }
 210                 }
 211         }
 212
 213         list_for_each_entry(entity, &rq->entities, list) {
 214
 215                 if (drm_sched_entity_is_ready(entity)) {
 216                         rq->current_entity = entity;
 217                         reinit_completion(&entity->entity_idle);
 218                         spin_unlock(&rq->lock);
 219                         return entity;
 220                 }
 221
 222                 if (entity == rq->current_entity)
 223                         break;
 224         }
 225
 226         spin_unlock(&rq->lock);
 227
 228         return NULL;
 229 }
 230
 231 /**
 232  * drm_sched_rq_select_entity_fifo - Select an entity which provides a job to run
 233  *
 234  * @rq: scheduler run queue to check.
 235  *
 236  * Find oldest waiting ready entity, returns NULL if none found.
 237  */
 238 static struct drm_sched_entity *
 239 drm_sched_rq_select_entity_fifo(struct drm_sched_rq *rq)
 240 {
 241         struct rb_node *rb;
 242
 243         spin_lock(&rq->lock);
 244         for (rb = rb_first_cached(&rq->rb_tree_root); rb; rb = rb_next(rb)) {
 245                 struct drm_sched_entity *entity;
 246
 247                 entity = rb_entry(rb, struct drm_sched_entity, rb_tree_node);
 248                 if (drm_sched_entity_is_ready(entity)) {
 249                         rq->current_entity = entity;
 250                         reinit_completion(&entity->entity_idle);
 251                         break;
 252                 }
 253         }
 254         spin_unlock(&rq->lock);
 255
 256         return rb ? rb_entry(rb, struct drm_sched_entity, rb_tree_node) : NULL;
 257 }
 258
 259 /**
 260  * drm_sched_job_done - complete a job
 261  * @s_job: pointer to the job which is done
 262  *
 263  * Finish the job's fence and wake up the worker thread.
 264  */
 265 static void drm_sched_job_done(struct drm_sched_job *s_job, int result)
 266 {
 267         struct drm_sched_fence *s_fence = s_job->s_fence;
 268         struct drm_gpu_scheduler *sched = s_fence->sched;
 269
 270         atomic_dec(&sched->hw_rq_count);
 271         atomic_dec(sched->score);
 272
 273         trace_drm_sched_process_job(s_fence);
 274
 275         dma_fence_get(&s_fence->finished);
 276         drm_sched_fence_finished(s_fence, result);
 277         dma_fence_put(&s_fence->finished);
 278         wake_up_interruptible(&sched->wake_up_worker);
 279 }
 280
 281 /**
 282  * drm_sched_job_done_cb - the callback for a done job
 283  * @f: fence
 284  * @cb: fence callbacks
 285  */
 286 static void drm_sched_job_done_cb(struct dma_fence *f, struct dma_fence_cb *cb)
 287 {
 288         struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb);
 289
 290         drm_sched_job_done(s_job, f->error);
 291 }
 292
 293 /**
 294  * drm_sched_start_timeout - start timeout for reset worker
 295  *
 296  * @sched: scheduler instance to start the worker for
 297  *
 298  * Start the timeout for the given scheduler.
 299  */
 300 static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched)
 301 {
 302         if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
 303             !list_empty(&sched->pending_list))
 304                 queue_delayed_work(sched->timeout_wq, &sched->work_tdr, sched->timeout);
 305 }
 306
 307 /**
 308  * drm_sched_fault - immediately start timeout handler
 309  *
 310  * @sched: scheduler where the timeout handling should be started.
 311  *
 312  * Start timeout handling immediately when the driver detects a hardware fault.
 313  */
 314 void drm_sched_fault(struct drm_gpu_scheduler *sched)
 315 {
 316         if (sched->timeout_wq)
 317                 mod_delayed_work(sched->timeout_wq, &sched->work_tdr, 0);
 318 }
 319 EXPORT_SYMBOL(drm_sched_fault);
 320
 321 /**
 322  * drm_sched_suspend_timeout - Suspend scheduler job timeout
 323  *
 324  * @sched: scheduler instance for which to suspend the timeout
 325  *
 326  * Suspend the delayed work timeout for the scheduler. This is done by
 327  * modifying the delayed work timeout to an arbitrary large value,
 328  * MAX_SCHEDULE_TIMEOUT in this case.
 329  *
 330  * Returns the timeout remaining
 331  *
 332  */
 333 unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched)
 334 {
 335         unsigned long sched_timeout, now = jiffies;
 336
 337         sched_timeout = sched->work_tdr.timer.expires;
 338
 339         /*
 340          * Modify the timeout to an arbitrarily large value. This also prevents
 341          * the timeout to be restarted when new submissions arrive
 342          */
 343         if (mod_delayed_work(sched->timeout_wq, &sched->work_tdr, MAX_SCHEDULE_TIMEOUT)
 344                         && time_after(sched_timeout, now))
 345                 return sched_timeout - now;
 346         else
 347                 return sched->timeout;
 348 }
 349 EXPORT_SYMBOL(drm_sched_suspend_timeout);
 350
 351 /**
 352  * drm_sched_resume_timeout - Resume scheduler job timeout
 353  *
 354  * @sched: scheduler instance for which to resume the timeout
 355  * @remaining: remaining timeout
 356  *
 357  * Resume the delayed work timeout for the scheduler.
 358  */
 359 void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
 360                 unsigned long remaining)
 361 {
 362         spin_lock(&sched->job_list_lock);
 363
 364         if (list_empty(&sched->pending_list))
 365                 cancel_delayed_work(&sched->work_tdr);
 366         else
 367                 mod_delayed_work(sched->timeout_wq, &sched->work_tdr, remaining);
 368
 369         spin_unlock(&sched->job_list_lock);
 370 }
 371 EXPORT_SYMBOL(drm_sched_resume_timeout);
 372
 373 static void drm_sched_job_begin(struct drm_sched_job *s_job)
 374 {
 375         struct drm_gpu_scheduler *sched = s_job->sched;
 376
 377         spin_lock(&sched->job_list_lock);
 378         list_add_tail(&s_job->list, &sched->pending_list);
 379         drm_sched_start_timeout(sched);
 380         spin_unlock(&sched->job_list_lock);
 381 }
 382
 383 static void drm_sched_job_timedout(struct work_struct *work)
 384 {
 385         struct drm_gpu_scheduler *sched;
 386         struct drm_sched_job *job;
 387         enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL;
 388
 389         sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
 390
 391         /* Protects against concurrent deletion in drm_sched_get_cleanup_job */
 392         spin_lock(&sched->job_list_lock);
 393         job = list_first_entry_or_null(&sched->pending_list,
 394                                        struct drm_sched_job, list);
 395
 396         if (job) {
 397                 /*
 398                  * Remove the bad job so it cannot be freed by concurrent
 399                  * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread
 400                  * is parked at which point it's safe.
 401                  */
 402                 list_del_init(&job->list);
 403                 spin_unlock(&sched->job_list_lock);
 404
 405                 status = job->sched->ops->timedout_job(job);
 406
 407                 /*
 408                  * Guilty job did complete and hence needs to be manually removed
 409                  * See drm_sched_stop doc.
 410                  */
 411                 if (sched->free_guilty) {
 412                         job->sched->ops->free_job(job);
 413                         sched->free_guilty = false;
 414                 }
 415         } else {
 416                 spin_unlock(&sched->job_list_lock);
 417         }
 418
 419         if (status != DRM_GPU_SCHED_STAT_ENODEV) {
 420                 spin_lock(&sched->job_list_lock);
 421                 drm_sched_start_timeout(sched);
 422                 spin_unlock(&sched->job_list_lock);
 423         }
 424 }
 425
 426 /**
 427  * drm_sched_stop - stop the scheduler
 428  *
 429  * @sched: scheduler instance
 430  * @bad: job which caused the time out
 431  *
 432  * Stop the scheduler and also removes and frees all completed jobs.
 433  * Note: bad job will not be freed as it might be used later and so it's
 434  * callers responsibility to release it manually if it's not part of the
 435  * pending list any more.
 436  *
 437  */
 438 void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
 439 {
 440         struct drm_sched_job *s_job, *tmp;
 441
 442         kthread_park(sched->thread);
 443
 444         /*
 445          * Reinsert back the bad job here - now it's safe as
 446          * drm_sched_get_cleanup_job cannot race against us and release the
 447          * bad job at this point - we parked (waited for) any in progress
 448          * (earlier) cleanups and drm_sched_get_cleanup_job will not be called
 449          * now until the scheduler thread is unparked.
 450          */
 451         if (bad && bad->sched == sched)
 452                 /*
 453                  * Add at the head of the queue to reflect it was the earliest
 454                  * job extracted.
 455                  */
 456                 list_add(&bad->list, &sched->pending_list);
 457
 458         /*
 459          * Iterate the job list from later to  earlier one and either deactive
 460          * their HW callbacks or remove them from pending list if they already
 461          * signaled.
 462          * This iteration is thread safe as sched thread is stopped.
 463          */
 464         list_for_each_entry_safe_reverse(s_job, tmp, &sched->pending_list,
 465                                          list) {
 466                 if (s_job->s_fence->parent &&
 467                     dma_fence_remove_callback(s_job->s_fence->parent,
 468                                               &s_job->cb)) {
 469                         dma_fence_put(s_job->s_fence->parent);
 470                         s_job->s_fence->parent = NULL;
 471                         atomic_dec(&sched->hw_rq_count);
 472                 } else {
 473                         /*
 474                          * remove job from pending_list.
 475                          * Locking here is for concurrent resume timeout
 476                          */
 477                         spin_lock(&sched->job_list_lock);
 478                         list_del_init(&s_job->list);
 479                         spin_unlock(&sched->job_list_lock);
 480
 481                         /*
 482                          * Wait for job's HW fence callback to finish using s_job
 483                          * before releasing it.
 484                          *
 485                          * Job is still alive so fence refcount at least 1
 486                          */
 487                         dma_fence_wait(&s_job->s_fence->finished, false);
 488
 489                         /*
 490                          * We must keep bad job alive for later use during
 491                          * recovery by some of the drivers but leave a hint
 492                          * that the guilty job must be released.
 493                          */
 494                         if (bad != s_job)
 495                                 sched->ops->free_job(s_job);
 496                         else
 497                                 sched->free_guilty = true;
 498                 }
 499         }
 500
 501         /*
 502          * Stop pending timer in flight as we rearm it in  drm_sched_start. This
 503          * avoids the pending timeout work in progress to fire right away after
 504          * this TDR finished and before the newly restarted jobs had a
 505          * chance to complete.
 506          */
 507         cancel_delayed_work(&sched->work_tdr);
 508 }
 509
 510 EXPORT_SYMBOL(drm_sched_stop);
 511
 512 /**
 513  * drm_sched_start - recover jobs after a reset
 514  *
 515  * @sched: scheduler instance
 516  * @full_recovery: proceed with complete sched restart
 517  *
 518  */
 519 void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery)
 520 {
 521         struct drm_sched_job *s_job, *tmp;
 522         int r;
 523
 524         /*
 525          * Locking the list is not required here as the sched thread is parked
 526          * so no new jobs are being inserted or removed. Also concurrent
 527          * GPU recovers can't run in parallel.
 528          */
 529         list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
 530                 struct dma_fence *fence = s_job->s_fence->parent;
 531
 532                 atomic_inc(&sched->hw_rq_count);
 533
 534                 if (!full_recovery)
 535                         continue;
 536
 537                 if (fence) {
 538                         r = dma_fence_add_callback(fence, &s_job->cb,
 539                                                    drm_sched_job_done_cb);
 540                         if (r == -ENOENT)
 541                                 drm_sched_job_done(s_job, fence->error);
 542                         else if (r)
 543                                 DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
 544                                           r);
 545                 } else
 546                         drm_sched_job_done(s_job, -ECANCELED);
 547         }
 548
 549         if (full_recovery) {
 550                 spin_lock(&sched->job_list_lock);
 551                 drm_sched_start_timeout(sched);
 552                 spin_unlock(&sched->job_list_lock);
 553         }
 554
 555         kthread_unpark(sched->thread);
 556 }
 557 EXPORT_SYMBOL(drm_sched_start);
 558
 559 /**
 560  * drm_sched_resubmit_jobs - Deprecated, don't use in new code!
 561  *
 562  * @sched: scheduler instance
 563  *
 564  * Re-submitting jobs was a concept AMD came up as cheap way to implement
 565  * recovery after a job timeout.
 566  *
 567  * This turned out to be not working very well. First of all there are many
 568  * problem with the dma_fence implementation and requirements. Either the
 569  * implementation is risking deadlocks with core memory management or violating
 570  * documented implementation details of the dma_fence object.
 571  *
 572  * Drivers can still save and restore their state for recovery operations, but
 573  * we shouldn't make this a general scheduler feature around the dma_fence
 574  * interface.
 575  */
 576 void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched)
 577 {
 578         struct drm_sched_job *s_job, *tmp;
 579         uint64_t guilty_context;
 580         bool found_guilty = false;
 581         struct dma_fence *fence;
 582
 583         list_for_each_entry_safe(s_job, tmp, &sched->pending_list, list) {
 584                 struct drm_sched_fence *s_fence = s_job->s_fence;
 585
 586                 if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) {
 587                         found_guilty = true;
 588                         guilty_context = s_job->s_fence->scheduled.context;
 589                 }
 590
 591                 if (found_guilty && s_job->s_fence->scheduled.context == guilty_context)
 592                         dma_fence_set_error(&s_fence->finished, -ECANCELED);
 593
 594                 fence = sched->ops->run_job(s_job);
 595
 596                 if (IS_ERR_OR_NULL(fence)) {
 597                         if (IS_ERR(fence))
 598                                 dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
 599
 600                         s_job->s_fence->parent = NULL;
 601                 } else {
 602
 603                         s_job->s_fence->parent = dma_fence_get(fence);
 604
 605                         /* Drop for orignal kref_init */
 606                         dma_fence_put(fence);
 607                 }
 608         }
 609 }
 610 EXPORT_SYMBOL(drm_sched_resubmit_jobs);
 611
 612 /**
 613  * drm_sched_job_init - init a scheduler job
 614  * @job: scheduler job to init
 615  * @entity: scheduler entity to use
 616  * @owner: job owner for debugging
 617  *
 618  * Refer to drm_sched_entity_push_job() documentation
 619  * for locking considerations.
 620  *
 621  * Drivers must make sure drm_sched_job_cleanup() if this function returns
 622  * successfully, even when @job is aborted before drm_sched_job_arm() is called.
 623  *
 624  * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware
 625  * has died, which can mean that there's no valid runqueue for a @entity.
 626  * This function returns -ENOENT in this case (which probably should be -EIO as
 627  * a more meanigful return value).
 628  *
 629  * Returns 0 for success, negative error code otherwise.
 630  */
 631 int drm_sched_job_init(struct drm_sched_job *job,
 632                        struct drm_sched_entity *entity,
 633                        void *owner)
 634 {
 635         if (!entity->rq)
 636                 return -ENOENT;
 637
 638         job->entity = entity;
 639         job->s_fence = drm_sched_fence_alloc(entity, owner);
 640         if (!job->s_fence)
 641                 return -ENOMEM;
 642
 643         INIT_LIST_HEAD(&job->list);
 644
 645         xa_init_flags(&job->dependencies, XA_FLAGS_ALLOC);
 646
 647         return 0;
 648 }
 649 EXPORT_SYMBOL(drm_sched_job_init);
 650
 651 /**
 652  * drm_sched_job_arm - arm a scheduler job for execution
 653  * @job: scheduler job to arm
 654  *
 655  * This arms a scheduler job for execution. Specifically it initializes the
 656  * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
 657  * or other places that need to track the completion of this job.
 658  *
 659  * Refer to drm_sched_entity_push_job() documentation for locking
 660  * considerations.
 661  *
 662  * This can only be called if drm_sched_job_init() succeeded.
 663  */
 664 void drm_sched_job_arm(struct drm_sched_job *job)
 665 {
 666         struct drm_gpu_scheduler *sched;
 667         struct drm_sched_entity *entity = job->entity;
 668
 669         BUG_ON(!entity);
 670         drm_sched_entity_select_rq(entity);
 671         sched = entity->rq->sched;
 672
 673         job->sched = sched;
 674         job->s_priority = entity->rq - sched->sched_rq;
 675         job->id = atomic64_inc_return(&sched->job_id_count);
 676
 677         drm_sched_fence_init(job->s_fence, job->entity);
 678 }
 679 EXPORT_SYMBOL(drm_sched_job_arm);
 680
 681 /**
 682  * drm_sched_job_add_dependency - adds the fence as a job dependency
 683  * @job: scheduler job to add the dependencies to
 684  * @fence: the dma_fence to add to the list of dependencies.
 685  *
 686  * Note that @fence is consumed in both the success and error cases.
 687  *
 688  * Returns:
 689  * 0 on success, or an error on failing to expand the array.
 690  */
 691 int drm_sched_job_add_dependency(struct drm_sched_job *job,
 692                                  struct dma_fence *fence)
 693 {
 694         struct dma_fence *entry;
 695         unsigned long index;
 696         u32 id = 0;
 697         int ret;
 698
 699         if (!fence)
 700                 return 0;
 701
 702         /* Deduplicate if we already depend on a fence from the same context.
 703          * This lets the size of the array of deps scale with the number of
 704          * engines involved, rather than the number of BOs.
 705          */
 706         xa_for_each(&job->dependencies, index, entry) {
 707                 if (entry->context != fence->context)
 708                         continue;
 709
 710                 if (dma_fence_is_later(fence, entry)) {
 711                         dma_fence_put(entry);
 712                         xa_store(&job->dependencies, index, fence, GFP_KERNEL);
 713                 } else {
 714                         dma_fence_put(fence);
 715                 }
 716                 return 0;
 717         }
 718
 719         ret = xa_alloc(&job->dependencies, &id, fence, xa_limit_32b, GFP_KERNEL);
 720         if (ret != 0)
 721                 dma_fence_put(fence);
 722
 723         return ret;
 724 }
 725 EXPORT_SYMBOL(drm_sched_job_add_dependency);
 726
 727 /**
 728  * drm_sched_job_add_syncobj_dependency - adds a syncobj's fence as a job dependency
 729  * @job: scheduler job to add the dependencies to
 730  * @file: drm file private pointer
 731  * @handle: syncobj handle to lookup
 732  * @point: timeline point
 733  *
 734  * This adds the fence matching the given syncobj to @job.
 735  *
 736  * Returns:
 737  * 0 on success, or an error on failing to expand the array.
 738  */
 739 int drm_sched_job_add_syncobj_dependency(struct drm_sched_job *job,
 740                                          struct drm_file *file,
 741                                          u32 handle,
 742                                          u32 point)
 743 {
 744         struct dma_fence *fence;
 745         int ret;
 746
 747         ret = drm_syncobj_find_fence(file, handle, point, 0, &fence);
 748         if (ret)
 749                 return ret;
 750
 751         return drm_sched_job_add_dependency(job, fence);
 752 }
 753 EXPORT_SYMBOL(drm_sched_job_add_syncobj_dependency);
 754
 755 /**
 756  * drm_sched_job_add_resv_dependencies - add all fences from the resv to the job
 757  * @job: scheduler job to add the dependencies to
 758  * @resv: the dma_resv object to get the fences from
 759  * @usage: the dma_resv_usage to use to filter the fences
 760  *
 761  * This adds all fences matching the given usage from @resv to @job.
 762  * Must be called with the @resv lock held.
 763  *
 764  * Returns:
 765  * 0 on success, or an error on failing to expand the array.
 766  */
 767 int drm_sched_job_add_resv_dependencies(struct drm_sched_job *job,
 768                                         struct dma_resv *resv,
 769                                         enum dma_resv_usage usage)
 770 {
 771         struct dma_resv_iter cursor;
 772         struct dma_fence *fence;
 773         int ret;
 774
 775         dma_resv_assert_held(resv);
 776
 777         dma_resv_for_each_fence(&cursor, resv, usage, fence) {
 778                 /* Make sure to grab an additional ref on the added fence */
 779                 dma_fence_get(fence);
 780                 ret = drm_sched_job_add_dependency(job, fence);
 781                 if (ret) {
 782                         dma_fence_put(fence);
 783                         return ret;
 784                 }
 785         }
 786         return 0;
 787 }
 788 EXPORT_SYMBOL(drm_sched_job_add_resv_dependencies);
 789
 790 /**
 791  * drm_sched_job_add_implicit_dependencies - adds implicit dependencies as job
 792  *   dependencies
 793  * @job: scheduler job to add the dependencies to
 794  * @obj: the gem object to add new dependencies from.
 795  * @write: whether the job might write the object (so we need to depend on
 796  * shared fences in the reservation object).
 797  *
 798  * This should be called after drm_gem_lock_reservations() on your array of
 799  * GEM objects used in the job but before updating the reservations with your
 800  * own fences.
 801  *
 802  * Returns:
 803  * 0 on success, or an error on failing to expand the array.
 804  */
 805 int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 806                                             struct drm_gem_object *obj,
 807                                             bool write)
 808 {
 809         return drm_sched_job_add_resv_dependencies(job, obj->resv,
 810                                                    dma_resv_usage_rw(write));
 811 }
 812 EXPORT_SYMBOL(drm_sched_job_add_implicit_dependencies);
 813
 814 /**
 815  * drm_sched_job_cleanup - clean up scheduler job resources
 816  * @job: scheduler job to clean up
 817  *
 818  * Cleans up the resources allocated with drm_sched_job_init().
 819  *
 820  * Drivers should call this from their error unwind code if @job is aborted
 821  * before drm_sched_job_arm() is called.
 822  *
 823  * After that point of no return @job is committed to be executed by the
 824  * scheduler, and this function should be called from the
 825  * &drm_sched_backend_ops.free_job callback.
 826  */
 827 void drm_sched_job_cleanup(struct drm_sched_job *job)
 828 {
 829         struct dma_fence *fence;
 830         unsigned long index;
 831
 832         if (kref_read(&job->s_fence->finished.refcount)) {
 833                 /* drm_sched_job_arm() has been called */
 834                 dma_fence_put(&job->s_fence->finished);
 835         } else {
 836                 /* aborted job before committing to run it */
 837                 drm_sched_fence_free(job->s_fence);
 838         }
 839
 840         job->s_fence = NULL;
 841
 842         xa_for_each(&job->dependencies, index, fence) {
 843                 dma_fence_put(fence);
 844         }
 845         xa_destroy(&job->dependencies);
 846
 847 }
 848 EXPORT_SYMBOL(drm_sched_job_cleanup);
 849
 850 /**
 851  * drm_sched_can_queue -- Can we queue more to the hardware?
 852  * @sched: scheduler instance
 853  *
 854  * Return true if we can push more jobs to the hw, otherwise false.
 855  */
 856 static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched)
 857 {
 858         return atomic_read(&sched->hw_rq_count) <
 859                 sched->hw_submission_limit;
 860 }
 861
 862 /**
 863  * drm_sched_wakeup_if_can_queue - Wake up the scheduler
 864  * @sched: scheduler instance
 865  *
 866  * Wake up the scheduler if we can queue jobs.
 867  */
 868 void drm_sched_wakeup_if_can_queue(struct drm_gpu_scheduler *sched)
 869 {
 870         if (drm_sched_can_queue(sched))
 871                 wake_up_interruptible(&sched->wake_up_worker);
 872 }
 873
 874 /**
 875  * drm_sched_select_entity - Select next entity to process
 876  *
 877  * @sched: scheduler instance
 878  *
 879  * Returns the entity to process or NULL if none are found.
 880  */
 881 static struct drm_sched_entity *
 882 drm_sched_select_entity(struct drm_gpu_scheduler *sched)
 883 {
 884         struct drm_sched_entity *entity;
 885         int i;
 886
 887         if (!drm_sched_can_queue(sched))
 888                 return NULL;
 889
 890         /* Kernel run queue has higher priority than normal run queue*/
 891         for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
 892                 entity = drm_sched_policy == DRM_SCHED_POLICY_FIFO ?
 893                         drm_sched_rq_select_entity_fifo(&sched->sched_rq[i]) :
 894                         drm_sched_rq_select_entity_rr(&sched->sched_rq[i]);
 895                 if (entity)
 896                         break;
 897         }
 898
 899         return entity;
 900 }
 901
 902 /**
 903  * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
 904  *
 905  * @sched: scheduler instance
 906  *
 907  * Returns the next finished job from the pending list (if there is one)
 908  * ready for it to be destroyed.
 909  */
 910 static struct drm_sched_job *
 911 drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
 912 {
 913         struct drm_sched_job *job, *next;
 914
 915         spin_lock(&sched->job_list_lock);
 916
 917         job = list_first_entry_or_null(&sched->pending_list,
 918                                        struct drm_sched_job, list);
 919
 920         if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
 921                 /* remove job from pending_list */
 922                 list_del_init(&job->list);
 923
 924                 /* cancel this job's TO timer */
 925                 cancel_delayed_work(&sched->work_tdr);
 926                 /* make the scheduled timestamp more accurate */
 927                 next = list_first_entry_or_null(&sched->pending_list,
 928                                                 typeof(*next), list);
 929
 930                 if (next) {
 931                         next->s_fence->scheduled.timestamp =
 932                                 job->s_fence->finished.timestamp;
 933                         /* start TO timer for next job */
 934                         drm_sched_start_timeout(sched);
 935                 }
 936         } else {
 937                 job = NULL;
 938         }
 939
 940         spin_unlock(&sched->job_list_lock);
 941
 942         return job;
 943 }
 944
 945 /**
 946  * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
 947  * @sched_list: list of drm_gpu_schedulers
 948  * @num_sched_list: number of drm_gpu_schedulers in the sched_list
 949  *
 950  * Returns pointer of the sched with the least load or NULL if none of the
 951  * drm_gpu_schedulers are ready
 952  */
 953 struct drm_gpu_scheduler *
 954 drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
 955                      unsigned int num_sched_list)
 956 {
 957         struct drm_gpu_scheduler *sched, *picked_sched = NULL;
 958         int i;
 959         unsigned int min_score = UINT_MAX, num_score;
 960
 961         for (i = 0; i < num_sched_list; ++i) {
 962                 sched = sched_list[i];
 963
 964                 if (!sched->ready) {
 965                         DRM_WARN("scheduler %s is not ready, skipping",
 966                                  sched->name);
 967                         continue;
 968                 }
 969
 970                 num_score = atomic_read(sched->score);
 971                 if (num_score < min_score) {
 972                         min_score = num_score;
 973                         picked_sched = sched;
 974                 }
 975         }
 976
 977         return picked_sched;
 978 }
 979 EXPORT_SYMBOL(drm_sched_pick_best);
 980
 981 /**
 982  * drm_sched_blocked - check if the scheduler is blocked
 983  *
 984  * @sched: scheduler instance
 985  *
 986  * Returns true if blocked, otherwise false.
 987  */
 988 static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
 989 {
 990         if (kthread_should_park()) {
 991                 kthread_parkme();
 992                 return true;
 993         }
 994
 995         return false;
 996 }
 997
 998 /**
 999  * drm_sched_main - main scheduler thread
1000  *
1001  * @param: scheduler instance
1002  *
1003  * Returns 0.
1004  */
1005 static int drm_sched_main(void *param)
1006 {
1007         struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
1008         int r;
1009
1010         sched_set_fifo_low(current);
1011
1012         while (!kthread_should_stop()) {
1013                 struct drm_sched_entity *entity = NULL;
1014                 struct drm_sched_fence *s_fence;
1015                 struct drm_sched_job *sched_job;
1016                 struct dma_fence *fence;
1017                 struct drm_sched_job *cleanup_job = NULL;
1018
1019                 wait_event_interruptible(sched->wake_up_worker,
1020                                          (cleanup_job = drm_sched_get_cleanup_job(sched)) ||
1021                                          (!drm_sched_blocked(sched) &&
1022                                           (entity = drm_sched_select_entity(sched))) ||
1023                                          kthread_should_stop());
1024
1025                 if (cleanup_job)
1026                         sched->ops->free_job(cleanup_job);
1027
1028                 if (!entity)
1029                         continue;
1030
1031                 sched_job = drm_sched_entity_pop_job(entity);
1032
1033                 if (!sched_job) {
1034                         complete_all(&entity->entity_idle);
1035                         continue;
1036                 }
1037
1038                 s_fence = sched_job->s_fence;
1039
1040                 atomic_inc(&sched->hw_rq_count);
1041                 drm_sched_job_begin(sched_job);
1042
1043                 trace_drm_run_job(sched_job, entity);
1044                 fence = sched->ops->run_job(sched_job);
1045                 complete_all(&entity->entity_idle);
1046                 drm_sched_fence_scheduled(s_fence);
1047
1048                 if (!IS_ERR_OR_NULL(fence)) {
1049                         drm_sched_fence_set_parent(s_fence, fence);
1050                         /* Drop for original kref_init of the fence */
1051                         dma_fence_put(fence);
1052
1053                         r = dma_fence_add_callback(fence, &sched_job->cb,
1054                                                    drm_sched_job_done_cb);
1055                         if (r == -ENOENT)
1056                                 drm_sched_job_done(sched_job, fence->error);
1057                         else if (r)
1058                                 DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
1059                                           r);
1060                 } else {
1061                         drm_sched_job_done(sched_job, IS_ERR(fence) ?
1062                                            PTR_ERR(fence) : 0);
1063                 }
1064
1065                 wake_up(&sched->job_scheduled);
1066         }
1067         return 0;
1068 }
1069
1070 /**
1071  * drm_sched_init - Init a gpu scheduler instance
1072  *
1073  * @sched: scheduler instance
1074  * @ops: backend operations for this scheduler
1075  * @hw_submission: number of hw submissions that can be in flight
1076  * @hang_limit: number of times to allow a job to hang before dropping it
1077  * @timeout: timeout value in jiffies for the scheduler
1078  * @timeout_wq: workqueue to use for timeout work. If NULL, the system_wq is
1079  *              used
1080  * @score: optional score atomic shared with other schedulers
1081  * @name: name used for debugging
1082  * @dev: target &struct device
1083  *
1084  * Return 0 on success, otherwise error code.
1085  */
1086 int drm_sched_init(struct drm_gpu_scheduler *sched,
1087                    const struct drm_sched_backend_ops *ops,
1088                    unsigned hw_submission, unsigned hang_limit,
1089                    long timeout, struct workqueue_struct *timeout_wq,
1090                    atomic_t *score, const char *name, struct device *dev)
1091 {
1092         int i, ret;
1093         sched->ops = ops;
1094         sched->hw_submission_limit = hw_submission;
1095         sched->name = name;
1096         sched->timeout = timeout;
1097         sched->timeout_wq = timeout_wq ? : system_wq;
1098         sched->hang_limit = hang_limit;
1099         sched->score = score ? score : &sched->_score;
1100         sched->dev = dev;
1101         for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; i++)
1102                 drm_sched_rq_init(sched, &sched->sched_rq[i]);
1103
1104         init_waitqueue_head(&sched->wake_up_worker);
1105         init_waitqueue_head(&sched->job_scheduled);
1106         INIT_LIST_HEAD(&sched->pending_list);
1107         spin_lock_init(&sched->job_list_lock);
1108         atomic_set(&sched->hw_rq_count, 0);
1109         INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
1110         atomic_set(&sched->_score, 0);
1111         atomic64_set(&sched->job_id_count, 0);
1112
1113         /* Each scheduler will run on a seperate kernel thread */
1114         sched->thread = kthread_run(drm_sched_main, sched, sched->name);
1115         if (IS_ERR(sched->thread)) {
1116                 ret = PTR_ERR(sched->thread);
1117                 sched->thread = NULL;
1118                 DRM_DEV_ERROR(sched->dev, "Failed to create scheduler for %s.\n", name);
1119                 return ret;
1120         }
1121
1122         sched->ready = true;
1123         return 0;
1124 }
1125 EXPORT_SYMBOL(drm_sched_init);
1126
1127 /**
1128  * drm_sched_fini - Destroy a gpu scheduler
1129  *
1130  * @sched: scheduler instance
1131  *
1132  * Tears down and cleans up the scheduler.
1133  */
1134 void drm_sched_fini(struct drm_gpu_scheduler *sched)
1135 {
1136         struct drm_sched_entity *s_entity;
1137         int i;
1138
1139         if (sched->thread)
1140                 kthread_stop(sched->thread);
1141
1142         for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
1143                 struct drm_sched_rq *rq = &sched->sched_rq[i];
1144
1145                 spin_lock(&rq->lock);
1146                 list_for_each_entry(s_entity, &rq->entities, list)
1147                         /*
1148                          * Prevents reinsertion and marks job_queue as idle,
1149                          * it will removed from rq in drm_sched_entity_fini
1150                          * eventually
1151                          */
1152                         s_entity->stopped = true;
1153                 spin_unlock(&rq->lock);
1154
1155         }
1156
1157         /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
1158         wake_up_all(&sched->job_scheduled);
1159
1160         /* Confirm no work left behind accessing device structures */
1161         cancel_delayed_work_sync(&sched->work_tdr);
1162
1163         sched->ready = false;
1164 }
1165 EXPORT_SYMBOL(drm_sched_fini);
1166
1167 /**
1168  * drm_sched_increase_karma - Update sched_entity guilty flag
1169  *
1170  * @bad: The job guilty of time out
1171  *
1172  * Increment on every hang caused by the 'bad' job. If this exceeds the hang
1173  * limit of the scheduler then the respective sched entity is marked guilty and
1174  * jobs from it will not be scheduled further
1175  */
1176 void drm_sched_increase_karma(struct drm_sched_job *bad)
1177 {
1178         int i;
1179         struct drm_sched_entity *tmp;
1180         struct drm_sched_entity *entity;
1181         struct drm_gpu_scheduler *sched = bad->sched;
1182
1183         /* don't change @bad's karma if it's from KERNEL RQ,
1184          * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
1185          * corrupt but keep in mind that kernel jobs always considered good.
1186          */
1187         if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
1188                 atomic_inc(&bad->karma);
1189
1190                 for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL;
1191                      i++) {
1192                         struct drm_sched_rq *rq = &sched->sched_rq[i];
1193
1194                         spin_lock(&rq->lock);
1195                         list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
1196                                 if (bad->s_fence->scheduled.context ==
1197                                     entity->fence_context) {
1198                                         if (entity->guilty)
1199                                                 atomic_set(entity->guilty, 1);
1200                                         break;
1201                                 }
1202                         }
1203                         spin_unlock(&rq->lock);
1204                         if (&entity->list != &rq->entities)
1205                                 break;
1206                 }
1207         }
1208 }
1209 EXPORT_SYMBOL(drm_sched_increase_karma);