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
  27 #include <drm/drm_print.h>
  28 #include <drm/gpu_scheduler.h>
  29
  30 #include "gpu_scheduler_trace.h"
  31
  32 #define to_drm_sched_job(sched_job)             \
  33                 container_of((sched_job), struct drm_sched_job, queue_node)
  34
  35 /**
  36  * drm_sched_entity_init - Init a context entity used by scheduler when
  37  * submit to HW ring.
  38  *
  39  * @entity: scheduler entity to init
  40  * @rq_list: the list of run queue on which jobs from this
  41  *           entity can be submitted
  42  * @num_rq_list: number of run queue in rq_list
  43  * @guilty: atomic_t set to 1 when a job on this queue
  44  *          is found to be guilty causing a timeout
  45  *
  46  * Note: the rq_list should have atleast one element to schedule
  47  *       the entity
  48  *
  49  * Returns 0 on success or a negative error code on failure.
  50  */
  51 int drm_sched_entity_init(struct drm_sched_entity *entity,
  52                           struct drm_sched_rq **rq_list,
  53                           unsigned int num_rq_list,
  54                           atomic_t *guilty)
  55 {
  56         int i;
  57
  58         if (!(entity && rq_list && (num_rq_list == 0 || rq_list[0])))
  59                 return -EINVAL;
  60
  61         memset(entity, 0, sizeof(struct drm_sched_entity));
  62         INIT_LIST_HEAD(&entity->list);
  63         entity->rq = NULL;
  64         entity->guilty = guilty;
  65         entity->num_rq_list = num_rq_list;
  66         entity->rq_list = kcalloc(num_rq_list, sizeof(struct drm_sched_rq *),
  67                                 GFP_KERNEL);
  68         if (!entity->rq_list)
  69                 return -ENOMEM;
  70
  71         for (i = 0; i < num_rq_list; ++i)
  72                 entity->rq_list[i] = rq_list[i];
  73
  74         if (num_rq_list)
  75                 entity->rq = rq_list[0];
  76
  77         entity->last_scheduled = NULL;
  78
  79         spin_lock_init(&entity->rq_lock);
  80         spsc_queue_init(&entity->job_queue);
  81
  82         atomic_set(&entity->fence_seq, 0);
  83         entity->fence_context = dma_fence_context_alloc(2);
  84
  85         return 0;
  86 }
  87 EXPORT_SYMBOL(drm_sched_entity_init);
  88
  89 /**
  90  * drm_sched_entity_is_idle - Check if entity is idle
  91  *
  92  * @entity: scheduler entity
  93  *
  94  * Returns true if the entity does not have any unscheduled jobs.
  95  */
  96 static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity)
  97 {
  98         rmb(); /* for list_empty to work without lock */
  99
 100         if (list_empty(&entity->list) ||
 101             spsc_queue_count(&entity->job_queue) == 0)
 102                 return true;
 103
 104         return false;
 105 }
 106
 107 /**
 108  * drm_sched_entity_is_ready - Check if entity is ready
 109  *
 110  * @entity: scheduler entity
 111  *
 112  * Return true if entity could provide a job.
 113  */
 114 bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
 115 {
 116         if (spsc_queue_peek(&entity->job_queue) == NULL)
 117                 return false;
 118
 119         if (READ_ONCE(entity->dependency))
 120                 return false;
 121
 122         return true;
 123 }
 124
 125 /**
 126  * drm_sched_entity_get_free_sched - Get the rq from rq_list with least load
 127  *
 128  * @entity: scheduler entity
 129  *
 130  * Return the pointer to the rq with least load.
 131  */
 132 static struct drm_sched_rq *
 133 drm_sched_entity_get_free_sched(struct drm_sched_entity *entity)
 134 {
 135         struct drm_sched_rq *rq = NULL;
 136         unsigned int min_jobs = UINT_MAX, num_jobs;
 137         int i;
 138
 139         for (i = 0; i < entity->num_rq_list; ++i) {
 140                 struct drm_gpu_scheduler *sched = entity->rq_list[i]->sched;
 141
 142                 if (!entity->rq_list[i]->sched->ready) {
 143                         DRM_WARN("sched%s is not ready, skipping", sched->name);
 144                         continue;
 145                 }
 146
 147                 num_jobs = atomic_read(&sched->num_jobs);
 148                 if (num_jobs < min_jobs) {
 149                         min_jobs = num_jobs;
 150                         rq = entity->rq_list[i];
 151                 }
 152         }
 153
 154         return rq;
 155 }
 156
 157 /**
 158  * drm_sched_entity_flush - Flush a context entity
 159  *
 160  * @entity: scheduler entity
 161  * @timeout: time to wait in for Q to become empty in jiffies.
 162  *
 163  * Splitting drm_sched_entity_fini() into two functions, The first one does the
 164  * waiting, removes the entity from the runqueue and returns an error when the
 165  * process was killed.
 166  *
 167  * Returns the remaining time in jiffies left from the input timeout
 168  */
 169 long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
 170 {
 171         struct drm_gpu_scheduler *sched;
 172         struct task_struct *last_user;
 173         long ret = timeout;
 174
 175         if (!entity->rq)
 176                 return 0;
 177
 178         sched = entity->rq->sched;
 179         /**
 180          * The client will not queue more IBs during this fini, consume existing
 181          * queued IBs or discard them on SIGKILL
 182          */
 183         if (current->flags & PF_EXITING) {
 184                 if (timeout)
 185                         ret = wait_event_timeout(
 186                                         sched->job_scheduled,
 187                                         drm_sched_entity_is_idle(entity),
 188                                         timeout);
 189         } else {
 190                 wait_event_killable(sched->job_scheduled,
 191                                     drm_sched_entity_is_idle(entity));
 192         }
 193
 194         /* For killed process disable any more IBs enqueue right now */
 195         last_user = cmpxchg(&entity->last_user, current->group_leader, NULL);
 196         if ((!last_user || last_user == current->group_leader) &&
 197             (current->flags & PF_EXITING) && (current->exit_code == SIGKILL)) {
 198                 spin_lock(&entity->rq_lock);
 199                 entity->stopped = true;
 200                 drm_sched_rq_remove_entity(entity->rq, entity);
 201                 spin_unlock(&entity->rq_lock);
 202         }
 203
 204         return ret;
 205 }
 206 EXPORT_SYMBOL(drm_sched_entity_flush);
 207
 208 /**
 209  * drm_sched_entity_kill_jobs - helper for drm_sched_entity_kill_jobs
 210  *
 211  * @f: signaled fence
 212  * @cb: our callback structure
 213  *
 214  * Signal the scheduler finished fence when the entity in question is killed.
 215  */
 216 static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
 217                                           struct dma_fence_cb *cb)
 218 {
 219         struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
 220                                                  finish_cb);
 221
 222         drm_sched_fence_finished(job->s_fence);
 223         WARN_ON(job->s_fence->parent);
 224         job->sched->ops->free_job(job);
 225 }
 226
 227 /**
 228  * drm_sched_entity_kill_jobs - Make sure all remaining jobs are killed
 229  *
 230  * @entity: entity which is cleaned up
 231  *
 232  * Makes sure that all remaining jobs in an entity are killed before it is
 233  * destroyed.
 234  */
 235 static void drm_sched_entity_kill_jobs(struct drm_sched_entity *entity)
 236 {
 237         struct drm_sched_job *job;
 238         int r;
 239
 240         while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {
 241                 struct drm_sched_fence *s_fence = job->s_fence;
 242
 243                 drm_sched_fence_scheduled(s_fence);
 244                 dma_fence_set_error(&s_fence->finished, -ESRCH);
 245
 246                 /*
 247                  * When pipe is hanged by older entity, new entity might
 248                  * not even have chance to submit it's first job to HW
 249                  * and so entity->last_scheduled will remain NULL
 250                  */
 251                 if (!entity->last_scheduled) {
 252                         drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
 253                         continue;
 254                 }
 255
 256                 r = dma_fence_add_callback(entity->last_scheduled,
 257                                            &job->finish_cb,
 258                                            drm_sched_entity_kill_jobs_cb);
 259                 if (r == -ENOENT)
 260                         drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
 261                 else if (r)
 262                         DRM_ERROR("fence add callback failed (%d)\n", r);
 263         }
 264 }
 265
 266 /**
 267  * drm_sched_entity_cleanup - Destroy a context entity
 268  *
 269  * @entity: scheduler entity
 270  *
 271  * This should be called after @drm_sched_entity_do_release. It goes over the
 272  * entity and signals all jobs with an error code if the process was killed.
 273  *
 274  */
 275 void drm_sched_entity_fini(struct drm_sched_entity *entity)
 276 {
 277         struct drm_gpu_scheduler *sched = NULL;
 278
 279         if (entity->rq) {
 280                 sched = entity->rq->sched;
 281                 drm_sched_rq_remove_entity(entity->rq, entity);
 282         }
 283
 284         /* Consumption of existing IBs wasn't completed. Forcefully
 285          * remove them here.
 286          */
 287         if (spsc_queue_count(&entity->job_queue)) {
 288                 if (sched) {
 289                         /* Park the kernel for a moment to make sure it isn't processing
 290                          * our enity.
 291                          */
 292                         kthread_park(sched->thread);
 293                         kthread_unpark(sched->thread);
 294                 }
 295                 if (entity->dependency) {
 296                         dma_fence_remove_callback(entity->dependency,
 297                                                   &entity->cb);
 298                         dma_fence_put(entity->dependency);
 299                         entity->dependency = NULL;
 300                 }
 301
 302                 drm_sched_entity_kill_jobs(entity);
 303         }
 304
 305         dma_fence_put(entity->last_scheduled);
 306         entity->last_scheduled = NULL;
 307         kfree(entity->rq_list);
 308 }
 309 EXPORT_SYMBOL(drm_sched_entity_fini);
 310
 311 /**
 312  * drm_sched_entity_fini - Destroy a context entity
 313  *
 314  * @entity: scheduler entity
 315  *
 316  * Calls drm_sched_entity_do_release() and drm_sched_entity_cleanup()
 317  */
 318 void drm_sched_entity_destroy(struct drm_sched_entity *entity)
 319 {
 320         drm_sched_entity_flush(entity, MAX_WAIT_SCHED_ENTITY_Q_EMPTY);
 321         drm_sched_entity_fini(entity);
 322 }
 323 EXPORT_SYMBOL(drm_sched_entity_destroy);
 324
 325 /**
 326  * drm_sched_entity_clear_dep - callback to clear the entities dependency
 327  */
 328 static void drm_sched_entity_clear_dep(struct dma_fence *f,
 329                                        struct dma_fence_cb *cb)
 330 {
 331         struct drm_sched_entity *entity =
 332                 container_of(cb, struct drm_sched_entity, cb);
 333
 334         entity->dependency = NULL;
 335         dma_fence_put(f);
 336 }
 337
 338 /**
 339  * drm_sched_entity_clear_dep - callback to clear the entities dependency and
 340  * wake up scheduler
 341  */
 342 static void drm_sched_entity_wakeup(struct dma_fence *f,
 343                                     struct dma_fence_cb *cb)
 344 {
 345         struct drm_sched_entity *entity =
 346                 container_of(cb, struct drm_sched_entity, cb);
 347
 348         drm_sched_entity_clear_dep(f, cb);
 349         drm_sched_wakeup(entity->rq->sched);
 350 }
 351
 352 /**
 353  * drm_sched_entity_set_rq_priority - helper for drm_sched_entity_set_priority
 354  */
 355 static void drm_sched_entity_set_rq_priority(struct drm_sched_rq **rq,
 356                                              enum drm_sched_priority priority)
 357 {
 358         *rq = &(*rq)->sched->sched_rq[priority];
 359 }
 360
 361 /**
 362  * drm_sched_entity_set_priority - Sets priority of the entity
 363  *
 364  * @entity: scheduler entity
 365  * @priority: scheduler priority
 366  *
 367  * Update the priority of runqueus used for the entity.
 368  */
 369 void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
 370                                    enum drm_sched_priority priority)
 371 {
 372         unsigned int i;
 373
 374         spin_lock(&entity->rq_lock);
 375
 376         for (i = 0; i < entity->num_rq_list; ++i)
 377                 drm_sched_entity_set_rq_priority(&entity->rq_list[i], priority);
 378
 379         if (entity->rq) {
 380                 drm_sched_rq_remove_entity(entity->rq, entity);
 381                 drm_sched_entity_set_rq_priority(&entity->rq, priority);
 382                 drm_sched_rq_add_entity(entity->rq, entity);
 383         }
 384
 385         spin_unlock(&entity->rq_lock);
 386 }
 387 EXPORT_SYMBOL(drm_sched_entity_set_priority);
 388
 389 /**
 390  * drm_sched_entity_add_dependency_cb - add callback for the entities dependency
 391  *
 392  * @entity: entity with dependency
 393  *
 394  * Add a callback to the current dependency of the entity to wake up the
 395  * scheduler when the entity becomes available.
 396  */
 397 static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
 398 {
 399         struct drm_gpu_scheduler *sched = entity->rq->sched;
 400         struct dma_fence *fence = entity->dependency;
 401         struct drm_sched_fence *s_fence;
 402
 403         if (fence->context == entity->fence_context ||
 404             fence->context == entity->fence_context + 1) {
 405                 /*
 406                  * Fence is a scheduled/finished fence from a job
 407                  * which belongs to the same entity, we can ignore
 408                  * fences from ourself
 409                  */
 410                 dma_fence_put(entity->dependency);
 411                 return false;
 412         }
 413
 414         s_fence = to_drm_sched_fence(fence);
 415         if (s_fence && s_fence->sched == sched) {
 416
 417                 /*
 418                  * Fence is from the same scheduler, only need to wait for
 419                  * it to be scheduled
 420                  */
 421                 fence = dma_fence_get(&s_fence->scheduled);
 422                 dma_fence_put(entity->dependency);
 423                 entity->dependency = fence;
 424                 if (!dma_fence_add_callback(fence, &entity->cb,
 425                                             drm_sched_entity_clear_dep))
 426                         return true;
 427
 428                 /* Ignore it when it is already scheduled */
 429                 dma_fence_put(fence);
 430                 return false;
 431         }
 432
 433         if (!dma_fence_add_callback(entity->dependency, &entity->cb,
 434                                     drm_sched_entity_wakeup))
 435                 return true;
 436
 437         dma_fence_put(entity->dependency);
 438         return false;
 439 }
 440
 441 /**
 442  * drm_sched_entity_pop_job - get a ready to be scheduled job from the entity
 443  *
 444  * @entity: entity to get the job from
 445  *
 446  * Process all dependencies and try to get one job from the entities queue.
 447  */
 448 struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
 449 {
 450         struct drm_gpu_scheduler *sched = entity->rq->sched;
 451         struct drm_sched_job *sched_job;
 452
 453         sched_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
 454         if (!sched_job)
 455                 return NULL;
 456
 457         while ((entity->dependency =
 458                         sched->ops->dependency(sched_job, entity))) {
 459                 trace_drm_sched_job_wait_dep(sched_job, entity->dependency);
 460
 461                 if (drm_sched_entity_add_dependency_cb(entity))
 462                         return NULL;
 463         }
 464
 465         /* skip jobs from entity that marked guilty */
 466         if (entity->guilty && atomic_read(entity->guilty))
 467                 dma_fence_set_error(&sched_job->s_fence->finished, -ECANCELED);
 468
 469         dma_fence_put(entity->last_scheduled);
 470         entity->last_scheduled = dma_fence_get(&sched_job->s_fence->finished);
 471
 472         spsc_queue_pop(&entity->job_queue);
 473         return sched_job;
 474 }
 475
 476 /**
 477  * drm_sched_entity_select_rq - select a new rq for the entity
 478  *
 479  * @entity: scheduler entity
 480  *
 481  * Check all prerequisites and select a new rq for the entity for load
 482  * balancing.
 483  */
 484 void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
 485 {
 486         struct dma_fence *fence;
 487         struct drm_sched_rq *rq;
 488
 489         if (spsc_queue_count(&entity->job_queue) || entity->num_rq_list <= 1)
 490                 return;
 491
 492         fence = READ_ONCE(entity->last_scheduled);
 493         if (fence && !dma_fence_is_signaled(fence))
 494                 return;
 495
 496         rq = drm_sched_entity_get_free_sched(entity);
 497         if (rq == entity->rq)
 498                 return;
 499
 500         spin_lock(&entity->rq_lock);
 501         drm_sched_rq_remove_entity(entity->rq, entity);
 502         entity->rq = rq;
 503         spin_unlock(&entity->rq_lock);
 504 }
 505
 506 /**
 507  * drm_sched_entity_push_job - Submit a job to the entity's job queue
 508  *
 509  * @sched_job: job to submit
 510  * @entity: scheduler entity
 511  *
 512  * Note: To guarantee that the order of insertion to queue matches
 513  * the job's fence sequence number this function should be
 514  * called with drm_sched_job_init under common lock.
 515  *
 516  * Returns 0 for success, negative error code otherwise.
 517  */
 518 void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
 519                                struct drm_sched_entity *entity)
 520 {
 521         bool first;
 522
 523         trace_drm_sched_job(sched_job, entity);
 524         atomic_inc(&entity->rq->sched->num_jobs);
 525         WRITE_ONCE(entity->last_user, current->group_leader);
 526         first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
 527
 528         /* first job wakes up scheduler */
 529         if (first) {
 530                 /* Add the entity to the run queue */
 531                 spin_lock(&entity->rq_lock);
 532                 if (entity->stopped) {
 533                         spin_unlock(&entity->rq_lock);
 534
 535                         DRM_ERROR("Trying to push to a killed entity\n");
 536                         return;
 537                 }
 538                 drm_sched_rq_add_entity(entity->rq, entity);
 539                 spin_unlock(&entity->rq_lock);
 540                 drm_sched_wakeup(entity->rq->sched);
 541         }
 542 }
 543 EXPORT_SYMBOL(drm_sched_entity_push_job);