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                 /* This will most likely be followed by missing frames
 637                  * or worse--a blank screen--leave a trail in the
 638                  * logs, so this can be debugged easier.
 639                  */
 640                 drm_err(job->sched, "%s: entity has no rq!\n", __func__);
 641                 return -ENOENT;
 642         }
 643
 644         job->entity = entity;
 645         job->s_fence = drm_sched_fence_alloc(entity, owner);
 646         if (!job->s_fence)
 647                 return -ENOMEM;
 648
 649         INIT_LIST_HEAD(&job->list);
 650
 651         xa_init_flags(&job->dependencies, XA_FLAGS_ALLOC);
 652
 653         return 0;
 654 }
 655 EXPORT_SYMBOL(drm_sched_job_init);
 656
 657 /**
 658  * drm_sched_job_arm - arm a scheduler job for execution
 659  * @job: scheduler job to arm
 660  *
 661  * This arms a scheduler job for execution. Specifically it initializes the
 662  * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv
 663  * or other places that need to track the completion of this job.
 664  *
 665  * Refer to drm_sched_entity_push_job() documentation for locking
 666  * considerations.
 667  *
 668  * This can only be called if drm_sched_job_init() succeeded.
 669  */
 670 void drm_sched_job_arm(struct drm_sched_job *job)
 671 {
 672         struct drm_gpu_scheduler *sched;
 673         struct drm_sched_entity *entity = job->entity;
 674
 675         BUG_ON(!entity);
 676         drm_sched_entity_select_rq(entity);
 677         sched = entity->rq->sched;
 678
 679         job->sched = sched;
 680         job->s_priority = entity->priority;
 681         job->id = atomic64_inc_return(&sched->job_id_count);
 682
 683         drm_sched_fence_init(job->s_fence, job->entity);
 684 }
 685 EXPORT_SYMBOL(drm_sched_job_arm);
 686
 687 /**
 688  * drm_sched_job_add_dependency - adds the fence as a job dependency
 689  * @job: scheduler job to add the dependencies to
 690  * @fence: the dma_fence to add to the list of dependencies.
 691  *
 692  * Note that @fence is consumed in both the success and error cases.
 693  *
 694  * Returns:
 695  * 0 on success, or an error on failing to expand the array.
 696  */
 697 int drm_sched_job_add_dependency(struct drm_sched_job *job,
 698                                  struct dma_fence *fence)
 699 {
 700         struct dma_fence *entry;
 701         unsigned long index;
 702         u32 id = 0;
 703         int ret;
 704
 705         if (!fence)
 706                 return 0;
 707
 708         /* Deduplicate if we already depend on a fence from the same context.
 709          * This lets the size of the array of deps scale with the number of
 710          * engines involved, rather than the number of BOs.
 711          */
 712         xa_for_each(&job->dependencies, index, entry) {
 713                 if (entry->context != fence->context)
 714                         continue;
 715
 716                 if (dma_fence_is_later(fence, entry)) {
 717                         dma_fence_put(entry);
 718                         xa_store(&job->dependencies, index, fence, GFP_KERNEL);
 719                 } else {
 720                         dma_fence_put(fence);
 721                 }
 722                 return 0;
 723         }
 724
 725         ret = xa_alloc(&job->dependencies, &id, fence, xa_limit_32b, GFP_KERNEL);
 726         if (ret != 0)
 727                 dma_fence_put(fence);
 728
 729         return ret;
 730 }
 731 EXPORT_SYMBOL(drm_sched_job_add_dependency);
 732
 733 /**
 734  * drm_sched_job_add_syncobj_dependency - adds a syncobj's fence as a job dependency
 735  * @job: scheduler job to add the dependencies to
 736  * @file: drm file private pointer
 737  * @handle: syncobj handle to lookup
 738  * @point: timeline point
 739  *
 740  * This adds the fence matching the given syncobj to @job.
 741  *
 742  * Returns:
 743  * 0 on success, or an error on failing to expand the array.
 744  */
 745 int drm_sched_job_add_syncobj_dependency(struct drm_sched_job *job,
 746                                          struct drm_file *file,
 747                                          u32 handle,
 748                                          u32 point)
 749 {
 750         struct dma_fence *fence;
 751         int ret;
 752
 753         ret = drm_syncobj_find_fence(file, handle, point, 0, &fence);
 754         if (ret)
 755                 return ret;
 756
 757         return drm_sched_job_add_dependency(job, fence);
 758 }
 759 EXPORT_SYMBOL(drm_sched_job_add_syncobj_dependency);
 760
 761 /**
 762  * drm_sched_job_add_resv_dependencies - add all fences from the resv to the job
 763  * @job: scheduler job to add the dependencies to
 764  * @resv: the dma_resv object to get the fences from
 765  * @usage: the dma_resv_usage to use to filter the fences
 766  *
 767  * This adds all fences matching the given usage from @resv to @job.
 768  * Must be called with the @resv lock held.
 769  *
 770  * Returns:
 771  * 0 on success, or an error on failing to expand the array.
 772  */
 773 int drm_sched_job_add_resv_dependencies(struct drm_sched_job *job,
 774                                         struct dma_resv *resv,
 775                                         enum dma_resv_usage usage)
 776 {
 777         struct dma_resv_iter cursor;
 778         struct dma_fence *fence;
 779         int ret;
 780
 781         dma_resv_assert_held(resv);
 782
 783         dma_resv_for_each_fence(&cursor, resv, usage, fence) {
 784                 /* Make sure to grab an additional ref on the added fence */
 785                 dma_fence_get(fence);
 786                 ret = drm_sched_job_add_dependency(job, fence);
 787                 if (ret) {
 788                         dma_fence_put(fence);
 789                         return ret;
 790                 }
 791         }
 792         return 0;
 793 }
 794 EXPORT_SYMBOL(drm_sched_job_add_resv_dependencies);
 795
 796 /**
 797  * drm_sched_job_add_implicit_dependencies - adds implicit dependencies as job
 798  *   dependencies
 799  * @job: scheduler job to add the dependencies to
 800  * @obj: the gem object to add new dependencies from.
 801  * @write: whether the job might write the object (so we need to depend on
 802  * shared fences in the reservation object).
 803  *
 804  * This should be called after drm_gem_lock_reservations() on your array of
 805  * GEM objects used in the job but before updating the reservations with your
 806  * own fences.
 807  *
 808  * Returns:
 809  * 0 on success, or an error on failing to expand the array.
 810  */
 811 int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
 812                                             struct drm_gem_object *obj,
 813                                             bool write)
 814 {
 815         return drm_sched_job_add_resv_dependencies(job, obj->resv,
 816                                                    dma_resv_usage_rw(write));
 817 }
 818 EXPORT_SYMBOL(drm_sched_job_add_implicit_dependencies);
 819
 820 /**
 821  * drm_sched_job_cleanup - clean up scheduler job resources
 822  * @job: scheduler job to clean up
 823  *
 824  * Cleans up the resources allocated with drm_sched_job_init().
 825  *
 826  * Drivers should call this from their error unwind code if @job is aborted
 827  * before drm_sched_job_arm() is called.
 828  *
 829  * After that point of no return @job is committed to be executed by the
 830  * scheduler, and this function should be called from the
 831  * &drm_sched_backend_ops.free_job callback.
 832  */
 833 void drm_sched_job_cleanup(struct drm_sched_job *job)
 834 {
 835         struct dma_fence *fence;
 836         unsigned long index;
 837
 838         if (kref_read(&job->s_fence->finished.refcount)) {
 839                 /* drm_sched_job_arm() has been called */
 840                 dma_fence_put(&job->s_fence->finished);
 841         } else {
 842                 /* aborted job before committing to run it */
 843                 drm_sched_fence_free(job->s_fence);
 844         }
 845
 846         job->s_fence = NULL;
 847
 848         xa_for_each(&job->dependencies, index, fence) {
 849                 dma_fence_put(fence);
 850         }
 851         xa_destroy(&job->dependencies);
 852
 853 }
 854 EXPORT_SYMBOL(drm_sched_job_cleanup);
 855
 856 /**
 857  * drm_sched_can_queue -- Can we queue more to the hardware?
 858  * @sched: scheduler instance
 859  *
 860  * Return true if we can push more jobs to the hw, otherwise false.
 861  */
 862 static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched)
 863 {
 864         return atomic_read(&sched->hw_rq_count) <
 865                 sched->hw_submission_limit;
 866 }
 867
 868 /**
 869  * drm_sched_wakeup_if_can_queue - Wake up the scheduler
 870  * @sched: scheduler instance
 871  *
 872  * Wake up the scheduler if we can queue jobs.
 873  */
 874 void drm_sched_wakeup_if_can_queue(struct drm_gpu_scheduler *sched)
 875 {
 876         if (drm_sched_can_queue(sched))
 877                 wake_up_interruptible(&sched->wake_up_worker);
 878 }
 879
 880 /**
 881  * drm_sched_select_entity - Select next entity to process
 882  *
 883  * @sched: scheduler instance
 884  *
 885  * Returns the entity to process or NULL if none are found.
 886  */
 887 static struct drm_sched_entity *
 888 drm_sched_select_entity(struct drm_gpu_scheduler *sched)
 889 {
 890         struct drm_sched_entity *entity;
 891         int i;
 892
 893         if (!drm_sched_can_queue(sched))
 894                 return NULL;
 895
 896         /* Kernel run queue has higher priority than normal run queue*/
 897         for (i = sched->num_rqs - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
 898                 entity = drm_sched_policy == DRM_SCHED_POLICY_FIFO ?
 899                         drm_sched_rq_select_entity_fifo(sched->sched_rq[i]) :
 900                         drm_sched_rq_select_entity_rr(sched->sched_rq[i]);
 901                 if (entity)
 902                         break;
 903         }
 904
 905         return entity;
 906 }
 907
 908 /**
 909  * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed
 910  *
 911  * @sched: scheduler instance
 912  *
 913  * Returns the next finished job from the pending list (if there is one)
 914  * ready for it to be destroyed.
 915  */
 916 static struct drm_sched_job *
 917 drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched)
 918 {
 919         struct drm_sched_job *job, *next;
 920
 921         spin_lock(&sched->job_list_lock);
 922
 923         job = list_first_entry_or_null(&sched->pending_list,
 924                                        struct drm_sched_job, list);
 925
 926         if (job && dma_fence_is_signaled(&job->s_fence->finished)) {
 927                 /* remove job from pending_list */
 928                 list_del_init(&job->list);
 929
 930                 /* cancel this job's TO timer */
 931                 cancel_delayed_work(&sched->work_tdr);
 932                 /* make the scheduled timestamp more accurate */
 933                 next = list_first_entry_or_null(&sched->pending_list,
 934                                                 typeof(*next), list);
 935
 936                 if (next) {
 937                         next->s_fence->scheduled.timestamp =
 938                                 dma_fence_timestamp(&job->s_fence->finished);
 939                         /* start TO timer for next job */
 940                         drm_sched_start_timeout(sched);
 941                 }
 942         } else {
 943                 job = NULL;
 944         }
 945
 946         spin_unlock(&sched->job_list_lock);
 947
 948         return job;
 949 }
 950
 951 /**
 952  * drm_sched_pick_best - Get a drm sched from a sched_list with the least load
 953  * @sched_list: list of drm_gpu_schedulers
 954  * @num_sched_list: number of drm_gpu_schedulers in the sched_list
 955  *
 956  * Returns pointer of the sched with the least load or NULL if none of the
 957  * drm_gpu_schedulers are ready
 958  */
 959 struct drm_gpu_scheduler *
 960 drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
 961                      unsigned int num_sched_list)
 962 {
 963         struct drm_gpu_scheduler *sched, *picked_sched = NULL;
 964         int i;
 965         unsigned int min_score = UINT_MAX, num_score;
 966
 967         for (i = 0; i < num_sched_list; ++i) {
 968                 sched = sched_list[i];
 969
 970                 if (!sched->ready) {
 971                         DRM_WARN("scheduler %s is not ready, skipping",
 972                                  sched->name);
 973                         continue;
 974                 }
 975
 976                 num_score = atomic_read(sched->score);
 977                 if (num_score < min_score) {
 978                         min_score = num_score;
 979                         picked_sched = sched;
 980                 }
 981         }
 982
 983         return picked_sched;
 984 }
 985 EXPORT_SYMBOL(drm_sched_pick_best);
 986
 987 /**
 988  * drm_sched_blocked - check if the scheduler is blocked
 989  *
 990  * @sched: scheduler instance
 991  *
 992  * Returns true if blocked, otherwise false.
 993  */
 994 static bool drm_sched_blocked(struct drm_gpu_scheduler *sched)
 995 {
 996         if (kthread_should_park()) {
 997                 kthread_parkme();
 998                 return true;
 999         }
1000
1001         return false;
1002 }
1003
1004 /**
1005  * drm_sched_main - main scheduler thread
1006  *
1007  * @param: scheduler instance
1008  *
1009  * Returns 0.
1010  */
1011 static int drm_sched_main(void *param)
1012 {
1013         struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
1014         int r;
1015
1016         sched_set_fifo_low(current);
1017
1018         while (!kthread_should_stop()) {
1019                 struct drm_sched_entity *entity = NULL;
1020                 struct drm_sched_fence *s_fence;
1021                 struct drm_sched_job *sched_job;
1022                 struct dma_fence *fence;
1023                 struct drm_sched_job *cleanup_job = NULL;
1024
1025                 wait_event_interruptible(sched->wake_up_worker,
1026                                          (cleanup_job = drm_sched_get_cleanup_job(sched)) ||
1027                                          (!drm_sched_blocked(sched) &&
1028                                           (entity = drm_sched_select_entity(sched))) ||
1029                                          kthread_should_stop());
1030
1031                 if (cleanup_job)
1032                         sched->ops->free_job(cleanup_job);
1033
1034                 if (!entity)
1035                         continue;
1036
1037                 sched_job = drm_sched_entity_pop_job(entity);
1038
1039                 if (!sched_job) {
1040                         complete_all(&entity->entity_idle);
1041                         continue;
1042                 }
1043
1044                 s_fence = sched_job->s_fence;
1045
1046                 atomic_inc(&sched->hw_rq_count);
1047                 drm_sched_job_begin(sched_job);
1048
1049                 trace_drm_run_job(sched_job, entity);
1050                 fence = sched->ops->run_job(sched_job);
1051                 complete_all(&entity->entity_idle);
1052                 drm_sched_fence_scheduled(s_fence, fence);
1053
1054                 if (!IS_ERR_OR_NULL(fence)) {
1055                         /* Drop for original kref_init of the fence */
1056                         dma_fence_put(fence);
1057
1058                         r = dma_fence_add_callback(fence, &sched_job->cb,
1059                                                    drm_sched_job_done_cb);
1060                         if (r == -ENOENT)
1061                                 drm_sched_job_done(sched_job, fence->error);
1062                         else if (r)
1063                                 DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
1064                                           r);
1065                 } else {
1066                         drm_sched_job_done(sched_job, IS_ERR(fence) ?
1067                                            PTR_ERR(fence) : 0);
1068                 }
1069
1070                 wake_up(&sched->job_scheduled);
1071         }
1072         return 0;
1073 }
1074
1075 /**
1076  * drm_sched_init - Init a gpu scheduler instance
1077  *
1078  * @sched: scheduler instance
1079  * @ops: backend operations for this scheduler
1080  * @num_rqs: number of runqueues, one for each priority, up to DRM_SCHED_PRIORITY_COUNT
1081  * @hw_submission: number of hw submissions that can be in flight
1082  * @hang_limit: number of times to allow a job to hang before dropping it
1083  * @timeout: timeout value in jiffies for the scheduler
1084  * @timeout_wq: workqueue to use for timeout work. If NULL, the system_wq is
1085  *              used
1086  * @score: optional score atomic shared with other schedulers
1087  * @name: name used for debugging
1088  * @dev: target &struct device
1089  *
1090  * Return 0 on success, otherwise error code.
1091  */
1092 int drm_sched_init(struct drm_gpu_scheduler *sched,
1093                    const struct drm_sched_backend_ops *ops,
1094                    u32 num_rqs, uint32_t hw_submission, unsigned int hang_limit,
1095                    long timeout, struct workqueue_struct *timeout_wq,
1096                    atomic_t *score, const char *name, struct device *dev)
1097 {
1098         int i, ret;
1099
1100         sched->ops = ops;
1101         sched->hw_submission_limit = hw_submission;
1102         sched->name = name;
1103         sched->timeout = timeout;
1104         sched->timeout_wq = timeout_wq ? : system_wq;
1105         sched->hang_limit = hang_limit;
1106         sched->score = score ? score : &sched->_score;
1107         sched->dev = dev;
1108
1109         if (num_rqs > DRM_SCHED_PRIORITY_COUNT) {
1110                 /* This is a gross violation--tell drivers what the  problem is.
1111                  */
1112                 drm_err(sched, "%s: num_rqs cannot be greater than DRM_SCHED_PRIORITY_COUNT\n",
1113                         __func__);
1114                 return -EINVAL;
1115         } else if (sched->sched_rq) {
1116                 /* Not an error, but warn anyway so drivers can
1117                  * fine-tune their DRM calling order, and return all
1118                  * is good.
1119                  */
1120                 drm_warn(sched, "%s: scheduler already initialized!\n", __func__);
1121                 return 0;
1122         }
1123
1124         sched->sched_rq = kmalloc_array(num_rqs, sizeof(*sched->sched_rq),
1125                                         GFP_KERNEL | __GFP_ZERO);
1126         if (!sched->sched_rq) {
1127                 drm_err(sched, "%s: out of memory for sched_rq\n", __func__);
1128                 return -ENOMEM;
1129         }
1130         sched->num_rqs = num_rqs;
1131         ret = -ENOMEM;
1132         for (i = DRM_SCHED_PRIORITY_MIN; i < sched->num_rqs; i++) {
1133                 sched->sched_rq[i] = kzalloc(sizeof(*sched->sched_rq[i]), GFP_KERNEL);
1134                 if (!sched->sched_rq[i])
1135                         goto Out_unroll;
1136                 drm_sched_rq_init(sched, sched->sched_rq[i]);
1137         }
1138
1139         init_waitqueue_head(&sched->wake_up_worker);
1140         init_waitqueue_head(&sched->job_scheduled);
1141         INIT_LIST_HEAD(&sched->pending_list);
1142         spin_lock_init(&sched->job_list_lock);
1143         atomic_set(&sched->hw_rq_count, 0);
1144         INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
1145         atomic_set(&sched->_score, 0);
1146         atomic64_set(&sched->job_id_count, 0);
1147
1148         /* Each scheduler will run on a seperate kernel thread */
1149         sched->thread = kthread_run(drm_sched_main, sched, sched->name);
1150         if (IS_ERR(sched->thread)) {
1151                 ret = PTR_ERR(sched->thread);
1152                 sched->thread = NULL;
1153                 DRM_DEV_ERROR(sched->dev, "Failed to create scheduler for %s.\n", name);
1154                 goto Out_unroll;
1155         }
1156
1157         sched->ready = true;
1158         return 0;
1159 Out_unroll:
1160         for (--i ; i >= DRM_SCHED_PRIORITY_MIN; i--)
1161                 kfree(sched->sched_rq[i]);
1162         kfree(sched->sched_rq);
1163         sched->sched_rq = NULL;
1164         drm_err(sched, "%s: Failed to setup GPU scheduler--out of memory\n", __func__);
1165         return ret;
1166 }
1167 EXPORT_SYMBOL(drm_sched_init);
1168
1169 /**
1170  * drm_sched_fini - Destroy a gpu scheduler
1171  *
1172  * @sched: scheduler instance
1173  *
1174  * Tears down and cleans up the scheduler.
1175  */
1176 void drm_sched_fini(struct drm_gpu_scheduler *sched)
1177 {
1178         struct drm_sched_entity *s_entity;
1179         int i;
1180
1181         if (sched->thread)
1182                 kthread_stop(sched->thread);
1183
1184         for (i = sched->num_rqs - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
1185                 struct drm_sched_rq *rq = sched->sched_rq[i];
1186
1187                 spin_lock(&rq->lock);
1188                 list_for_each_entry(s_entity, &rq->entities, list)
1189                         /*
1190                          * Prevents reinsertion and marks job_queue as idle,
1191                          * it will removed from rq in drm_sched_entity_fini
1192                          * eventually
1193                          */
1194                         s_entity->stopped = true;
1195                 spin_unlock(&rq->lock);
1196                 kfree(sched->sched_rq[i]);
1197         }
1198
1199         /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */
1200         wake_up_all(&sched->job_scheduled);
1201
1202         /* Confirm no work left behind accessing device structures */
1203         cancel_delayed_work_sync(&sched->work_tdr);
1204
1205         sched->ready = false;
1206         kfree(sched->sched_rq);
1207         sched->sched_rq = NULL;
1208 }
1209 EXPORT_SYMBOL(drm_sched_fini);
1210
1211 /**
1212  * drm_sched_increase_karma - Update sched_entity guilty flag
1213  *
1214  * @bad: The job guilty of time out
1215  *
1216  * Increment on every hang caused by the 'bad' job. If this exceeds the hang
1217  * limit of the scheduler then the respective sched entity is marked guilty and
1218  * jobs from it will not be scheduled further
1219  */
1220 void drm_sched_increase_karma(struct drm_sched_job *bad)
1221 {
1222         int i;
1223         struct drm_sched_entity *tmp;
1224         struct drm_sched_entity *entity;
1225         struct drm_gpu_scheduler *sched = bad->sched;
1226
1227         /* don't change @bad's karma if it's from KERNEL RQ,
1228          * because sometimes GPU hang would cause kernel jobs (like VM updating jobs)
1229          * corrupt but keep in mind that kernel jobs always considered good.
1230          */
1231         if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
1232                 atomic_inc(&bad->karma);
1233
1234                 for (i = DRM_SCHED_PRIORITY_MIN;
1235                      i < min_t(typeof(sched->num_rqs), sched->num_rqs, DRM_SCHED_PRIORITY_KERNEL);
1236                      i++) {
1237                         struct drm_sched_rq *rq = sched->sched_rq[i];
1238
1239                         spin_lock(&rq->lock);
1240                         list_for_each_entry_safe(entity, tmp, &rq->entities, list) {
1241                                 if (bad->s_fence->scheduled.context ==
1242                                     entity->fence_context) {
1243                                         if (entity->guilty)
1244                                                 atomic_set(entity->guilty, 1);
1245                                         break;
1246                                 }
1247                         }
1248                         spin_unlock(&rq->lock);
1249                         if (&entity->list != &rq->entities)
1250                                 break;
1251                 }
1252         }
1253 }
1254 EXPORT_SYMBOL(drm_sched_increase_karma);