drivers/gpu/drm/scheduler/sched_entity.c

   1 /*
   2  * Copyright 2015 Advanced Micro Devices, Inc.
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice shall be included in
  12  * all copies or substantial portions of the Software.
  13  *
  14  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  15  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  17  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  18  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  19  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  20  * OTHER DEALINGS IN THE SOFTWARE.
  21  *
  22  */
  23
  24 #include <linux/kthread.h>
  25 #include <drm/gpu_scheduler.h>
  26
  27 #include "gpu_scheduler_trace.h"
  28
  29 #define to_drm_sched_job(sched_job)             \
  30                 container_of((sched_job), struct drm_sched_job, queue_node)
  31
  32 /**
  33  * drm_sched_entity_init - Init a context entity used by scheduler when
  34  * submit to HW ring.
  35  *
  36  * @entity: scheduler entity to init
  37  * @rq_list: the list of run queue on which jobs from this
  38  *           entity can be submitted
  39  * @num_rq_list: number of run queue in rq_list
  40  * @guilty: atomic_t set to 1 when a job on this queue
  41  *          is found to be guilty causing a timeout
  42  *
  43  * Note: the rq_list should have atleast one element to schedule
  44  *       the entity
  45  *
  46  * Returns 0 on success or a negative error code on failure.
  47  */
  48 int drm_sched_entity_init(struct drm_sched_entity *entity,
  49                           struct drm_sched_rq **rq_list,
  50                           unsigned int num_rq_list,
  51                           atomic_t *guilty)
  52 {
  53         int i;
  54
  55         if (!(entity && rq_list && (num_rq_list == 0 || rq_list[0])))
  56                 return -EINVAL;
  57
  58         memset(entity, 0, sizeof(struct drm_sched_entity));
  59         INIT_LIST_HEAD(&entity->list);
  60         entity->rq = NULL;
  61         entity->guilty = guilty;
  62         entity->num_rq_list = num_rq_list;
  63         entity->rq_list = kcalloc(num_rq_list, sizeof(struct drm_sched_rq *),
  64                                 GFP_KERNEL);
  65         if (!entity->rq_list)
  66                 return -ENOMEM;
  67
  68         for (i = 0; i < num_rq_list; ++i)
  69                 entity->rq_list[i] = rq_list[i];
  70
  71         if (num_rq_list)
  72                 entity->rq = rq_list[0];
  73
  74         entity->last_scheduled = NULL;
  75
  76         spin_lock_init(&entity->rq_lock);
  77         spsc_queue_init(&entity->job_queue);
  78
  79         atomic_set(&entity->fence_seq, 0);
  80         entity->fence_context = dma_fence_context_alloc(2);
  81
  82         return 0;
  83 }
  84 EXPORT_SYMBOL(drm_sched_entity_init);
  85
  86 /**
  87  * drm_sched_entity_is_idle - Check if entity is idle
  88  *
  89  * @entity: scheduler entity
  90  *
  91  * Returns true if the entity does not have any unscheduled jobs.
  92  */
  93 static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity)
  94 {
  95         rmb(); /* for list_empty to work without lock */
  96
  97         if (list_empty(&entity->list) ||
  98             spsc_queue_count(&entity->job_queue) == 0)
  99                 return true;
 100
 101         return false;
 102 }
 103
 104 /**
 105  * drm_sched_entity_is_ready - Check if entity is ready
 106  *
 107  * @entity: scheduler entity
 108  *
 109  * Return true if entity could provide a job.
 110  */
 111 bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
 112 {
 113         if (spsc_queue_peek(&entity->job_queue) == NULL)
 114                 return false;
 115
 116         if (READ_ONCE(entity->dependency))
 117                 return false;
 118
 119         return true;
 120 }
 121
 122 /**
 123  * drm_sched_entity_get_free_sched - Get the rq from rq_list with least load
 124  *
 125  * @entity: scheduler entity
 126  *
 127  * Return the pointer to the rq with least load.
 128  */
 129 static struct drm_sched_rq *
 130 drm_sched_entity_get_free_sched(struct drm_sched_entity *entity)
 131 {
 132         struct drm_sched_rq *rq = NULL;
 133         unsigned int min_jobs = UINT_MAX, num_jobs;
 134         int i;
 135
 136         for (i = 0; i < entity->num_rq_list; ++i) {
 137                 struct drm_gpu_scheduler *sched = entity->rq_list[i]->sched;
 138
 139                 if (!entity->rq_list[i]->sched->ready) {
 140                         DRM_WARN("sched%s is not ready, skipping", sched->name);
 141                         continue;
 142                 }
 143
 144                 num_jobs = atomic_read(&sched->num_jobs);
 145                 if (num_jobs < min_jobs) {
 146                         min_jobs = num_jobs;
 147                         rq = entity->rq_list[i];
 148                 }
 149         }
 150
 151         return rq;
 152 }
 153
 154 /**
 155  * drm_sched_entity_flush - Flush a context entity
 156  *
 157  * @entity: scheduler entity
 158  * @timeout: time to wait in for Q to become empty in jiffies.
 159  *
 160  * Splitting drm_sched_entity_fini() into two functions, The first one does the
 161  * waiting, removes the entity from the runqueue and returns an error when the
 162  * process was killed.
 163  *
 164  * Returns the remaining time in jiffies left from the input timeout
 165  */
 166 long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
 167 {
 168         struct drm_gpu_scheduler *sched;
 169         struct task_struct *last_user;
 170         long ret = timeout;
 171
 172         if (!entity->rq)
 173                 return 0;
 174
 175         sched = entity->rq->sched;
 176         /**
 177          * The client will not queue more IBs during this fini, consume existing
 178          * queued IBs or discard them on SIGKILL
 179          */
 180         if (current->flags & PF_EXITING) {
 181                 if (timeout)
 182                         ret = wait_event_timeout(
 183                                         sched->job_scheduled,
 184                                         drm_sched_entity_is_idle(entity),
 185                                         timeout);
 186         } else {
 187                 wait_event_killable(sched->job_scheduled,
 188                                     drm_sched_entity_is_idle(entity));
 189         }
 190
 191         /* For killed process disable any more IBs enqueue right now */
 192         last_user = cmpxchg(&entity->last_user, current->group_leader, NULL);
 193         if ((!last_user || last_user == current->group_leader) &&
 194             (current->flags & PF_EXITING) && (current->exit_code == SIGKILL)) {
 195                 spin_lock(&entity->rq_lock);
 196                 entity->stopped = true;
 197                 drm_sched_rq_remove_entity(entity->rq, entity);
 198                 spin_unlock(&entity->rq_lock);
 199         }
 200
 201         return ret;
 202 }
 203 EXPORT_SYMBOL(drm_sched_entity_flush);
 204
 205 /**
 206  * drm_sched_entity_kill_jobs - helper for drm_sched_entity_kill_jobs
 207  *
 208  * @f: signaled fence
 209  * @cb: our callback structure
 210  *
 211  * Signal the scheduler finished fence when the entity in question is killed.
 212  */
 213 static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
 214                                           struct dma_fence_cb *cb)
 215 {
 216         struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
 217                                                  finish_cb);
 218
 219         drm_sched_fence_finished(job->s_fence);
 220         WARN_ON(job->s_fence->parent);
 221         job->sched->ops->free_job(job);
 222 }
 223
 224 /**
 225  * drm_sched_entity_kill_jobs - Make sure all remaining jobs are killed
 226  *
 227  * @entity: entity which is cleaned up
 228  *
 229  * Makes sure that all remaining jobs in an entity are killed before it is
 230  * destroyed.
 231  */
 232 static void drm_sched_entity_kill_jobs(struct drm_sched_entity *entity)
 233 {
 234         struct drm_sched_job *job;
 235         int r;
 236
 237         while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {
 238                 struct drm_sched_fence *s_fence = job->s_fence;
 239
 240                 drm_sched_fence_scheduled(s_fence);
 241                 dma_fence_set_error(&s_fence->finished, -ESRCH);
 242
 243                 /*
 244                  * When pipe is hanged by older entity, new entity might
 245                  * not even have chance to submit it's first job to HW
 246                  * and so entity->last_scheduled will remain NULL
 247                  */
 248                 if (!entity->last_scheduled) {
 249                         drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
 250                         continue;
 251                 }
 252
 253                 r = dma_fence_add_callback(entity->last_scheduled,
 254                                            &job->finish_cb,
 255                                            drm_sched_entity_kill_jobs_cb);
 256                 if (r == -ENOENT)
 257                         drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
 258                 else if (r)
 259                         DRM_ERROR("fence add callback failed (%d)\n", r);
 260         }
 261 }
 262
 263 /**
 264  * drm_sched_entity_cleanup - Destroy a context entity
 265  *
 266  * @entity: scheduler entity
 267  *
 268  * This should be called after @drm_sched_entity_do_release. It goes over the
 269  * entity and signals all jobs with an error code if the process was killed.
 270  *
 271  */
 272 void drm_sched_entity_fini(struct drm_sched_entity *entity)
 273 {
 274         struct drm_gpu_scheduler *sched = NULL;
 275
 276         if (entity->rq) {
 277                 sched = entity->rq->sched;
 278                 drm_sched_rq_remove_entity(entity->rq, entity);
 279         }
 280
 281         /* Consumption of existing IBs wasn't completed. Forcefully
 282          * remove them here.
 283          */
 284         if (spsc_queue_count(&entity->job_queue)) {
 285                 if (sched) {
 286                         /* Park the kernel for a moment to make sure it isn't processing
 287                          * our enity.
 288                          */
 289                         kthread_park(sched->thread);
 290                         kthread_unpark(sched->thread);
 291                 }
 292                 if (entity->dependency) {
 293                         dma_fence_remove_callback(entity->dependency,
 294                                                   &entity->cb);
 295                         dma_fence_put(entity->dependency);
 296                         entity->dependency = NULL;
 297                 }
 298
 299                 drm_sched_entity_kill_jobs(entity);
 300         }
 301
 302         dma_fence_put(entity->last_scheduled);
 303         entity->last_scheduled = NULL;
 304         kfree(entity->rq_list);
 305 }
 306 EXPORT_SYMBOL(drm_sched_entity_fini);
 307
 308 /**
 309  * drm_sched_entity_fini - Destroy a context entity
 310  *
 311  * @entity: scheduler entity
 312  *
 313  * Calls drm_sched_entity_do_release() and drm_sched_entity_cleanup()
 314  */
 315 void drm_sched_entity_destroy(struct drm_sched_entity *entity)
 316 {
 317         drm_sched_entity_flush(entity, MAX_WAIT_SCHED_ENTITY_Q_EMPTY);
 318         drm_sched_entity_fini(entity);
 319 }
 320 EXPORT_SYMBOL(drm_sched_entity_destroy);
 321
 322 /**
 323  * drm_sched_entity_clear_dep - callback to clear the entities dependency
 324  */
 325 static void drm_sched_entity_clear_dep(struct dma_fence *f,
 326                                        struct dma_fence_cb *cb)
 327 {
 328         struct drm_sched_entity *entity =
 329                 container_of(cb, struct drm_sched_entity, cb);
 330
 331         entity->dependency = NULL;
 332         dma_fence_put(f);
 333 }
 334
 335 /**
 336  * drm_sched_entity_clear_dep - callback to clear the entities dependency and
 337  * wake up scheduler
 338  */
 339 static void drm_sched_entity_wakeup(struct dma_fence *f,
 340                                     struct dma_fence_cb *cb)
 341 {
 342         struct drm_sched_entity *entity =
 343                 container_of(cb, struct drm_sched_entity, cb);
 344
 345         drm_sched_entity_clear_dep(f, cb);
 346         drm_sched_wakeup(entity->rq->sched);
 347 }
 348
 349 /**
 350  * drm_sched_entity_set_rq_priority - helper for drm_sched_entity_set_priority
 351  */
 352 static void drm_sched_entity_set_rq_priority(struct drm_sched_rq **rq,
 353                                              enum drm_sched_priority priority)
 354 {
 355         *rq = &(*rq)->sched->sched_rq[priority];
 356 }
 357
 358 /**
 359  * drm_sched_entity_set_priority - Sets priority of the entity
 360  *
 361  * @entity: scheduler entity
 362  * @priority: scheduler priority
 363  *
 364  * Update the priority of runqueus used for the entity.
 365  */
 366 void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
 367                                    enum drm_sched_priority priority)
 368 {
 369         unsigned int i;
 370
 371         spin_lock(&entity->rq_lock);
 372
 373         for (i = 0; i < entity->num_rq_list; ++i)
 374                 drm_sched_entity_set_rq_priority(&entity->rq_list[i], priority);
 375
 376         if (entity->rq) {
 377                 drm_sched_rq_remove_entity(entity->rq, entity);
 378                 drm_sched_entity_set_rq_priority(&entity->rq, priority);
 379                 drm_sched_rq_add_entity(entity->rq, entity);
 380         }
 381
 382         spin_unlock(&entity->rq_lock);
 383 }
 384 EXPORT_SYMBOL(drm_sched_entity_set_priority);
 385
 386 /**
 387  * drm_sched_entity_add_dependency_cb - add callback for the entities dependency
 388  *
 389  * @entity: entity with dependency
 390  *
 391  * Add a callback to the current dependency of the entity to wake up the
 392  * scheduler when the entity becomes available.
 393  */
 394 static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
 395 {
 396         struct drm_gpu_scheduler *sched = entity->rq->sched;
 397         struct dma_fence *fence = entity->dependency;
 398         struct drm_sched_fence *s_fence;
 399
 400         if (fence->context == entity->fence_context ||
 401             fence->context == entity->fence_context + 1) {
 402                 /*
 403                  * Fence is a scheduled/finished fence from a job
 404                  * which belongs to the same entity, we can ignore
 405                  * fences from ourself
 406                  */
 407                 dma_fence_put(entity->dependency);
 408                 return false;
 409         }
 410
 411         s_fence = to_drm_sched_fence(fence);
 412         if (s_fence && s_fence->sched == sched) {
 413
 414                 /*
 415                  * Fence is from the same scheduler, only need to wait for
 416                  * it to be scheduled
 417                  */
 418                 fence = dma_fence_get(&s_fence->scheduled);
 419                 dma_fence_put(entity->dependency);
 420                 entity->dependency = fence;
 421                 if (!dma_fence_add_callback(fence, &entity->cb,
 422                                             drm_sched_entity_clear_dep))
 423                         return true;
 424
 425                 /* Ignore it when it is already scheduled */
 426                 dma_fence_put(fence);
 427                 return false;
 428         }
 429
 430         if (!dma_fence_add_callback(entity->dependency, &entity->cb,
 431                                     drm_sched_entity_wakeup))
 432                 return true;
 433
 434         dma_fence_put(entity->dependency);
 435         return false;
 436 }
 437
 438 /**
 439  * drm_sched_entity_pop_job - get a ready to be scheduled job from the entity
 440  *
 441  * @entity: entity to get the job from
 442  *
 443  * Process all dependencies and try to get one job from the entities queue.
 444  */
 445 struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
 446 {
 447         struct drm_gpu_scheduler *sched = entity->rq->sched;
 448         struct drm_sched_job *sched_job;
 449
 450         sched_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
 451         if (!sched_job)
 452                 return NULL;
 453
 454         while ((entity->dependency =
 455                         sched->ops->dependency(sched_job, entity))) {
 456                 trace_drm_sched_job_wait_dep(sched_job, entity->dependency);
 457
 458                 if (drm_sched_entity_add_dependency_cb(entity))
 459                         return NULL;
 460         }
 461
 462         /* skip jobs from entity that marked guilty */
 463         if (entity->guilty && atomic_read(entity->guilty))
 464                 dma_fence_set_error(&sched_job->s_fence->finished, -ECANCELED);
 465
 466         dma_fence_put(entity->last_scheduled);
 467         entity->last_scheduled = dma_fence_get(&sched_job->s_fence->finished);
 468
 469         spsc_queue_pop(&entity->job_queue);
 470         return sched_job;
 471 }
 472
 473 /**
 474  * drm_sched_entity_select_rq - select a new rq for the entity
 475  *
 476  * @entity: scheduler entity
 477  *
 478  * Check all prerequisites and select a new rq for the entity for load
 479  * balancing.
 480  */
 481 void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
 482 {
 483         struct dma_fence *fence;
 484         struct drm_sched_rq *rq;
 485
 486         if (spsc_queue_count(&entity->job_queue) || entity->num_rq_list <= 1)
 487                 return;
 488
 489         fence = READ_ONCE(entity->last_scheduled);
 490         if (fence && !dma_fence_is_signaled(fence))
 491                 return;
 492
 493         rq = drm_sched_entity_get_free_sched(entity);
 494         if (rq == entity->rq)
 495                 return;
 496
 497         spin_lock(&entity->rq_lock);
 498         drm_sched_rq_remove_entity(entity->rq, entity);
 499         entity->rq = rq;
 500         spin_unlock(&entity->rq_lock);
 501 }
 502
 503 /**
 504  * drm_sched_entity_push_job - Submit a job to the entity's job queue
 505  *
 506  * @sched_job: job to submit
 507  * @entity: scheduler entity
 508  *
 509  * Note: To guarantee that the order of insertion to queue matches
 510  * the job's fence sequence number this function should be
 511  * called with drm_sched_job_init under common lock.
 512  *
 513  * Returns 0 for success, negative error code otherwise.
 514  */
 515 void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
 516                                struct drm_sched_entity *entity)
 517 {
 518         bool first;
 519
 520         trace_drm_sched_job(sched_job, entity);
 521         atomic_inc(&entity->rq->sched->num_jobs);
 522         WRITE_ONCE(entity->last_user, current->group_leader);
 523         first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
 524
 525         /* first job wakes up scheduler */
 526         if (first) {
 527                 /* Add the entity to the run queue */
 528                 spin_lock(&entity->rq_lock);
 529                 if (entity->stopped) {
 530                         spin_unlock(&entity->rq_lock);
 531
 532                         DRM_ERROR("Trying to push to a killed entity\n");
 533                         return;
 534                 }
 535                 drm_sched_rq_add_entity(entity->rq, entity);
 536                 spin_unlock(&entity->rq_lock);
 537                 drm_sched_wakeup(entity->rq->sched);
 538         }
 539 }
 540 EXPORT_SYMBOL(drm_sched_entity_push_job);