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 <linux/slab.h>
  26 #include <linux/completion.h>
  27
  28 #include <drm/drm_print.h>
  29 #include <drm/gpu_scheduler.h>
  30
  31 #include "gpu_scheduler_trace.h"
  32
  33 #define to_drm_sched_job(sched_job)             \
  34                 container_of((sched_job), struct drm_sched_job, queue_node)
  35
  36 /**
  37  * drm_sched_entity_init - Init a context entity used by scheduler when
  38  * submit to HW ring.
  39  *
  40  * @entity: scheduler entity to init
  41  * @priority: priority of the entity
  42  * @sched_list: the list of drm scheds on which jobs from this
  43  *           entity can be submitted
  44  * @num_sched_list: number of drm sched in sched_list
  45  * @guilty: atomic_t set to 1 when a job on this queue
  46  *          is found to be guilty causing a timeout
  47  *
  48  * Note: the sched_list should have at least one element to schedule
  49  *       the entity
  50  *
  51  * Returns 0 on success or a negative error code on failure.
  52  */
  53 int drm_sched_entity_init(struct drm_sched_entity *entity,
  54                           enum drm_sched_priority priority,
  55                           struct drm_gpu_scheduler **sched_list,
  56                           unsigned int num_sched_list,
  57                           atomic_t *guilty)
  58 {
  59         if (!(entity && sched_list && (num_sched_list == 0 || sched_list[0])))
  60                 return -EINVAL;
  61
  62         memset(entity, 0, sizeof(struct drm_sched_entity));
  63         INIT_LIST_HEAD(&entity->list);
  64         entity->rq = NULL;
  65         entity->guilty = guilty;
  66         entity->num_sched_list = num_sched_list;
  67         entity->priority = priority;
  68         entity->sched_list = num_sched_list > 1 ? sched_list : NULL;
  69         entity->last_scheduled = NULL;
  70
  71         if(num_sched_list)
  72                 entity->rq = &sched_list[0]->sched_rq[entity->priority];
  73
  74         init_completion(&entity->entity_idle);
  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_modify_sched - Modify sched of an entity
  88  * @entity: scheduler entity to init
  89  * @sched_list: the list of new drm scheds which will replace
  90  *               existing entity->sched_list
  91  * @num_sched_list: number of drm sched in sched_list
  92  */
  93 void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
  94                                     struct drm_gpu_scheduler **sched_list,
  95                                     unsigned int num_sched_list)
  96 {
  97         WARN_ON(!num_sched_list || !sched_list);
  98
  99         entity->sched_list = sched_list;
 100         entity->num_sched_list = num_sched_list;
 101 }
 102 EXPORT_SYMBOL(drm_sched_entity_modify_sched);
 103
 104 /**
 105  * drm_sched_entity_is_idle - Check if entity is idle
 106  *
 107  * @entity: scheduler entity
 108  *
 109  * Returns true if the entity does not have any unscheduled jobs.
 110  */
 111 static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity)
 112 {
 113         rmb(); /* for list_empty to work without lock */
 114
 115         if (list_empty(&entity->list) ||
 116             spsc_queue_count(&entity->job_queue) == 0)
 117                 return true;
 118
 119         return false;
 120 }
 121
 122 /**
 123  * drm_sched_entity_is_ready - Check if entity is ready
 124  *
 125  * @entity: scheduler entity
 126  *
 127  * Return true if entity could provide a job.
 128  */
 129 bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
 130 {
 131         if (spsc_queue_peek(&entity->job_queue) == NULL)
 132                 return false;
 133
 134         if (READ_ONCE(entity->dependency))
 135                 return false;
 136
 137         return true;
 138 }
 139
 140 /**
 141  * drm_sched_entity_flush - Flush a context entity
 142  *
 143  * @entity: scheduler entity
 144  * @timeout: time to wait in for Q to become empty in jiffies.
 145  *
 146  * Splitting drm_sched_entity_fini() into two functions, The first one does the
 147  * waiting, removes the entity from the runqueue and returns an error when the
 148  * process was killed.
 149  *
 150  * Returns the remaining time in jiffies left from the input timeout
 151  */
 152 long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
 153 {
 154         struct drm_gpu_scheduler *sched;
 155         struct task_struct *last_user;
 156         long ret = timeout;
 157
 158         if (!entity->rq)
 159                 return 0;
 160
 161         sched = entity->rq->sched;
 162         /**
 163          * The client will not queue more IBs during this fini, consume existing
 164          * queued IBs or discard them on SIGKILL
 165          */
 166         if (current->flags & PF_EXITING) {
 167                 if (timeout)
 168                         ret = wait_event_timeout(
 169                                         sched->job_scheduled,
 170                                         drm_sched_entity_is_idle(entity),
 171                                         timeout);
 172         } else {
 173                 wait_event_killable(sched->job_scheduled,
 174                                     drm_sched_entity_is_idle(entity));
 175         }
 176
 177         /* For killed process disable any more IBs enqueue right now */
 178         last_user = cmpxchg(&entity->last_user, current->group_leader, NULL);
 179         if ((!last_user || last_user == current->group_leader) &&
 180             (current->flags & PF_EXITING) && (current->exit_code == SIGKILL)) {
 181                 spin_lock(&entity->rq_lock);
 182                 entity->stopped = true;
 183                 drm_sched_rq_remove_entity(entity->rq, entity);
 184                 spin_unlock(&entity->rq_lock);
 185         }
 186
 187         return ret;
 188 }
 189 EXPORT_SYMBOL(drm_sched_entity_flush);
 190
 191 /**
 192  * drm_sched_entity_kill_jobs - helper for drm_sched_entity_kill_jobs
 193  *
 194  * @f: signaled fence
 195  * @cb: our callback structure
 196  *
 197  * Signal the scheduler finished fence when the entity in question is killed.
 198  */
 199 static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
 200                                           struct dma_fence_cb *cb)
 201 {
 202         struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
 203                                                  finish_cb);
 204
 205         drm_sched_fence_finished(job->s_fence);
 206         WARN_ON(job->s_fence->parent);
 207         job->sched->ops->free_job(job);
 208 }
 209
 210 /**
 211  * drm_sched_entity_kill_jobs - Make sure all remaining jobs are killed
 212  *
 213  * @entity: entity which is cleaned up
 214  *
 215  * Makes sure that all remaining jobs in an entity are killed before it is
 216  * destroyed.
 217  */
 218 static void drm_sched_entity_kill_jobs(struct drm_sched_entity *entity)
 219 {
 220         struct drm_sched_job *job;
 221         int r;
 222
 223         while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {
 224                 struct drm_sched_fence *s_fence = job->s_fence;
 225
 226                 drm_sched_fence_scheduled(s_fence);
 227                 dma_fence_set_error(&s_fence->finished, -ESRCH);
 228
 229                 /*
 230                  * When pipe is hanged by older entity, new entity might
 231                  * not even have chance to submit it's first job to HW
 232                  * and so entity->last_scheduled will remain NULL
 233                  */
 234                 if (!entity->last_scheduled) {
 235                         drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
 236                         continue;
 237                 }
 238
 239                 r = dma_fence_add_callback(entity->last_scheduled,
 240                                            &job->finish_cb,
 241                                            drm_sched_entity_kill_jobs_cb);
 242                 if (r == -ENOENT)
 243                         drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
 244                 else if (r)
 245                         DRM_ERROR("fence add callback failed (%d)\n", r);
 246         }
 247 }
 248
 249 /**
 250  * drm_sched_entity_cleanup - Destroy a context entity
 251  *
 252  * @entity: scheduler entity
 253  *
 254  * This should be called after @drm_sched_entity_do_release. It goes over the
 255  * entity and signals all jobs with an error code if the process was killed.
 256  *
 257  */
 258 void drm_sched_entity_fini(struct drm_sched_entity *entity)
 259 {
 260         struct drm_gpu_scheduler *sched = NULL;
 261
 262         if (entity->rq) {
 263                 sched = entity->rq->sched;
 264                 drm_sched_rq_remove_entity(entity->rq, entity);
 265         }
 266
 267         /* Consumption of existing IBs wasn't completed. Forcefully
 268          * remove them here.
 269          */
 270         if (spsc_queue_count(&entity->job_queue)) {
 271                 if (sched) {
 272                         /*
 273                          * Wait for thread to idle to make sure it isn't processing
 274                          * this entity.
 275                          */
 276                         wait_for_completion(&entity->entity_idle);
 277
 278                 }
 279                 if (entity->dependency) {
 280                         dma_fence_remove_callback(entity->dependency,
 281                                                   &entity->cb);
 282                         dma_fence_put(entity->dependency);
 283                         entity->dependency = NULL;
 284                 }
 285
 286                 drm_sched_entity_kill_jobs(entity);
 287         }
 288
 289         dma_fence_put(entity->last_scheduled);
 290         entity->last_scheduled = NULL;
 291 }
 292 EXPORT_SYMBOL(drm_sched_entity_fini);
 293
 294 /**
 295  * drm_sched_entity_fini - Destroy a context entity
 296  *
 297  * @entity: scheduler entity
 298  *
 299  * Calls drm_sched_entity_do_release() and drm_sched_entity_cleanup()
 300  */
 301 void drm_sched_entity_destroy(struct drm_sched_entity *entity)
 302 {
 303         drm_sched_entity_flush(entity, MAX_WAIT_SCHED_ENTITY_Q_EMPTY);
 304         drm_sched_entity_fini(entity);
 305 }
 306 EXPORT_SYMBOL(drm_sched_entity_destroy);
 307
 308 /**
 309  * drm_sched_entity_clear_dep - callback to clear the entities dependency
 310  */
 311 static void drm_sched_entity_clear_dep(struct dma_fence *f,
 312                                        struct dma_fence_cb *cb)
 313 {
 314         struct drm_sched_entity *entity =
 315                 container_of(cb, struct drm_sched_entity, cb);
 316
 317         entity->dependency = NULL;
 318         dma_fence_put(f);
 319 }
 320
 321 /**
 322  * drm_sched_entity_clear_dep - callback to clear the entities dependency and
 323  * wake up scheduler
 324  */
 325 static void drm_sched_entity_wakeup(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         drm_sched_entity_clear_dep(f, cb);
 332         drm_sched_wakeup(entity->rq->sched);
 333 }
 334
 335 /**
 336  * drm_sched_entity_set_priority - Sets priority of the entity
 337  *
 338  * @entity: scheduler entity
 339  * @priority: scheduler priority
 340  *
 341  * Update the priority of runqueus used for the entity.
 342  */
 343 void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
 344                                    enum drm_sched_priority priority)
 345 {
 346         spin_lock(&entity->rq_lock);
 347         entity->priority = priority;
 348         spin_unlock(&entity->rq_lock);
 349 }
 350 EXPORT_SYMBOL(drm_sched_entity_set_priority);
 351
 352 /**
 353  * drm_sched_entity_add_dependency_cb - add callback for the entities dependency
 354  *
 355  * @entity: entity with dependency
 356  *
 357  * Add a callback to the current dependency of the entity to wake up the
 358  * scheduler when the entity becomes available.
 359  */
 360 static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
 361 {
 362         struct drm_gpu_scheduler *sched = entity->rq->sched;
 363         struct dma_fence *fence = entity->dependency;
 364         struct drm_sched_fence *s_fence;
 365
 366         if (fence->context == entity->fence_context ||
 367             fence->context == entity->fence_context + 1) {
 368                 /*
 369                  * Fence is a scheduled/finished fence from a job
 370                  * which belongs to the same entity, we can ignore
 371                  * fences from ourself
 372                  */
 373                 dma_fence_put(entity->dependency);
 374                 return false;
 375         }
 376
 377         s_fence = to_drm_sched_fence(fence);
 378         if (s_fence && s_fence->sched == sched) {
 379
 380                 /*
 381                  * Fence is from the same scheduler, only need to wait for
 382                  * it to be scheduled
 383                  */
 384                 fence = dma_fence_get(&s_fence->scheduled);
 385                 dma_fence_put(entity->dependency);
 386                 entity->dependency = fence;
 387                 if (!dma_fence_add_callback(fence, &entity->cb,
 388                                             drm_sched_entity_clear_dep))
 389                         return true;
 390
 391                 /* Ignore it when it is already scheduled */
 392                 dma_fence_put(fence);
 393                 return false;
 394         }
 395
 396         if (!dma_fence_add_callback(entity->dependency, &entity->cb,
 397                                     drm_sched_entity_wakeup))
 398                 return true;
 399
 400         dma_fence_put(entity->dependency);
 401         return false;
 402 }
 403
 404 /**
 405  * drm_sched_entity_pop_job - get a ready to be scheduled job from the entity
 406  *
 407  * @entity: entity to get the job from
 408  *
 409  * Process all dependencies and try to get one job from the entities queue.
 410  */
 411 struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
 412 {
 413         struct drm_gpu_scheduler *sched = entity->rq->sched;
 414         struct drm_sched_job *sched_job;
 415
 416         sched_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
 417         if (!sched_job)
 418                 return NULL;
 419
 420         while ((entity->dependency =
 421                         sched->ops->dependency(sched_job, entity))) {
 422                 trace_drm_sched_job_wait_dep(sched_job, entity->dependency);
 423
 424                 if (drm_sched_entity_add_dependency_cb(entity))
 425                         return NULL;
 426         }
 427
 428         /* skip jobs from entity that marked guilty */
 429         if (entity->guilty && atomic_read(entity->guilty))
 430                 dma_fence_set_error(&sched_job->s_fence->finished, -ECANCELED);
 431
 432         dma_fence_put(entity->last_scheduled);
 433         entity->last_scheduled = dma_fence_get(&sched_job->s_fence->finished);
 434
 435         spsc_queue_pop(&entity->job_queue);
 436         return sched_job;
 437 }
 438
 439 /**
 440  * drm_sched_entity_select_rq - select a new rq for the entity
 441  *
 442  * @entity: scheduler entity
 443  *
 444  * Check all prerequisites and select a new rq for the entity for load
 445  * balancing.
 446  */
 447 void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
 448 {
 449         struct dma_fence *fence;
 450         struct drm_gpu_scheduler *sched;
 451         struct drm_sched_rq *rq;
 452
 453         if (spsc_queue_count(&entity->job_queue) || entity->num_sched_list <= 1)
 454                 return;
 455
 456         fence = READ_ONCE(entity->last_scheduled);
 457         if (fence && !dma_fence_is_signaled(fence))
 458                 return;
 459
 460         spin_lock(&entity->rq_lock);
 461         sched = drm_sched_pick_best(entity->sched_list, entity->num_sched_list);
 462         rq = sched ? &sched->sched_rq[entity->priority] : NULL;
 463         if (rq != entity->rq) {
 464                 drm_sched_rq_remove_entity(entity->rq, entity);
 465                 entity->rq = rq;
 466         }
 467
 468         spin_unlock(&entity->rq_lock);
 469 }
 470
 471 /**
 472  * drm_sched_entity_push_job - Submit a job to the entity's job queue
 473  *
 474  * @sched_job: job to submit
 475  * @entity: scheduler entity
 476  *
 477  * Note: To guarantee that the order of insertion to queue matches
 478  * the job's fence sequence number this function should be
 479  * called with drm_sched_job_init under common lock.
 480  *
 481  * Returns 0 for success, negative error code otherwise.
 482  */
 483 void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
 484                                struct drm_sched_entity *entity)
 485 {
 486         bool first;
 487
 488         trace_drm_sched_job(sched_job, entity);
 489         atomic_inc(&entity->rq->sched->num_jobs);
 490         WRITE_ONCE(entity->last_user, current->group_leader);
 491         first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
 492
 493         /* first job wakes up scheduler */
 494         if (first) {
 495                 /* Add the entity to the run queue */
 496                 spin_lock(&entity->rq_lock);
 497                 if (entity->stopped) {
 498                         spin_unlock(&entity->rq_lock);
 499
 500                         DRM_ERROR("Trying to push to a killed entity\n");
 501                         return;
 502                 }
 503                 drm_sched_rq_add_entity(entity->rq, entity);
 504                 spin_unlock(&entity->rq_lock);
 505                 drm_sched_wakeup(entity->rq->sched);
 506         }
 507 }
 508 EXPORT_SYMBOL(drm_sched_entity_push_job);