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 #ifndef _DRM_GPU_SCHEDULER_H_ 25 #define _DRM_GPU_SCHEDULER_H_ 26 27 #include <drm/spsc_queue.h> 28 #include <linux/dma-fence.h> 29 #include <linux/completion.h> 30 #include <linux/xarray.h> 31 #include <linux/workqueue.h> 32 33 #define MAX_WAIT_SCHED_ENTITY_Q_EMPTY msecs_to_jiffies(1000) 34 35 struct drm_gem_object; 36 37 struct drm_gpu_scheduler; 38 struct drm_sched_rq; 39 40 /* These are often used as an (initial) index 41 * to an array, and as such should start at 0. 42 */ 43 enum drm_sched_priority { 44 DRM_SCHED_PRIORITY_MIN, 45 DRM_SCHED_PRIORITY_NORMAL, 46 DRM_SCHED_PRIORITY_HIGH, 47 DRM_SCHED_PRIORITY_KERNEL, 48 49 DRM_SCHED_PRIORITY_COUNT, 50 DRM_SCHED_PRIORITY_UNSET = -2 51 }; 52 53 /** 54 * struct drm_sched_entity - A wrapper around a job queue (typically 55 * attached to the DRM file_priv). 56 * 57 * Entities will emit jobs in order to their corresponding hardware 58 * ring, and the scheduler will alternate between entities based on 59 * scheduling policy. 60 */ 61 struct drm_sched_entity { 62 /** 63 * @list: 64 * 65 * Used to append this struct to the list of entities in the runqueue 66 * @rq under &drm_sched_rq.entities. 67 * 68 * Protected by &drm_sched_rq.lock of @rq. 69 */ 70 struct list_head list; 71 72 /** 73 * @rq: 74 * 75 * Runqueue on which this entity is currently scheduled. 76 * 77 * FIXME: Locking is very unclear for this. Writers are protected by 78 * @rq_lock, but readers are generally lockless and seem to just race 79 * with not even a READ_ONCE. 80 */ 81 struct drm_sched_rq *rq; 82 83 /** 84 * @sched_list: 85 * 86 * A list of schedulers (struct drm_gpu_scheduler). Jobs from this entity can 87 * be scheduled on any scheduler on this list. 88 * 89 * This can be modified by calling drm_sched_entity_modify_sched(). 90 * Locking is entirely up to the driver, see the above function for more 91 * details. 92 * 93 * This will be set to NULL if &num_sched_list equals 1 and @rq has been 94 * set already. 95 * 96 * FIXME: This means priority changes through 97 * drm_sched_entity_set_priority() will be lost henceforth in this case. 98 */ 99 struct drm_gpu_scheduler **sched_list; 100 101 /** 102 * @num_sched_list: 103 * 104 * Number of drm_gpu_schedulers in the @sched_list. 105 */ 106 unsigned int num_sched_list; 107 108 /** 109 * @priority: 110 * 111 * Priority of the entity. This can be modified by calling 112 * drm_sched_entity_set_priority(). Protected by &rq_lock. 113 */ 114 enum drm_sched_priority priority; 115 116 /** 117 * @rq_lock: 118 * 119 * Lock to modify the runqueue to which this entity belongs. 120 */ 121 spinlock_t rq_lock; 122 123 /** 124 * @job_queue: the list of jobs of this entity. 125 */ 126 struct spsc_queue job_queue; 127 128 /** 129 * @fence_seq: 130 * 131 * A linearly increasing seqno incremented with each new 132 * &drm_sched_fence which is part of the entity. 133 * 134 * FIXME: Callers of drm_sched_job_arm() need to ensure correct locking, 135 * this doesn't need to be atomic. 136 */ 137 atomic_t fence_seq; 138 139 /** 140 * @fence_context: 141 * 142 * A unique context for all the fences which belong to this entity. The 143 * &drm_sched_fence.scheduled uses the fence_context but 144 * &drm_sched_fence.finished uses fence_context + 1. 145 */ 146 uint64_t fence_context; 147 148 /** 149 * @dependency: 150 * 151 * The dependency fence of the job which is on the top of the job queue. 152 */ 153 struct dma_fence *dependency; 154 155 /** 156 * @cb: 157 * 158 * Callback for the dependency fence above. 159 */ 160 struct dma_fence_cb cb; 161 162 /** 163 * @guilty: 164 * 165 * Points to entities' guilty. 166 */ 167 atomic_t *guilty; 168 169 /** 170 * @last_scheduled: 171 * 172 * Points to the finished fence of the last scheduled job. Only written 173 * by the scheduler thread, can be accessed locklessly from 174 * drm_sched_job_arm() iff the queue is empty. 175 */ 176 struct dma_fence *last_scheduled; 177 178 /** 179 * @last_user: last group leader pushing a job into the entity. 180 */ 181 struct task_struct *last_user; 182 183 /** 184 * @stopped: 185 * 186 * Marks the enity as removed from rq and destined for 187 * termination. This is set by calling drm_sched_entity_flush() and by 188 * drm_sched_fini(). 189 */ 190 bool stopped; 191 192 /** 193 * @entity_idle: 194 * 195 * Signals when entity is not in use, used to sequence entity cleanup in 196 * drm_sched_entity_fini(). 197 */ 198 struct completion entity_idle; 199 }; 200 201 /** 202 * struct drm_sched_rq - queue of entities to be scheduled. 203 * 204 * @lock: to modify the entities list. 205 * @sched: the scheduler to which this rq belongs to. 206 * @entities: list of the entities to be scheduled. 207 * @current_entity: the entity which is to be scheduled. 208 * 209 * Run queue is a set of entities scheduling command submissions for 210 * one specific ring. It implements the scheduling policy that selects 211 * the next entity to emit commands from. 212 */ 213 struct drm_sched_rq { 214 spinlock_t lock; 215 struct drm_gpu_scheduler *sched; 216 struct list_head entities; 217 struct drm_sched_entity *current_entity; 218 }; 219 220 /** 221 * struct drm_sched_fence - fences corresponding to the scheduling of a job. 222 */ 223 struct drm_sched_fence { 224 /** 225 * @scheduled: this fence is what will be signaled by the scheduler 226 * when the job is scheduled. 227 */ 228 struct dma_fence scheduled; 229 230 /** 231 * @finished: this fence is what will be signaled by the scheduler 232 * when the job is completed. 233 * 234 * When setting up an out fence for the job, you should use 235 * this, since it's available immediately upon 236 * drm_sched_job_init(), and the fence returned by the driver 237 * from run_job() won't be created until the dependencies have 238 * resolved. 239 */ 240 struct dma_fence finished; 241 242 /** 243 * @parent: the fence returned by &drm_sched_backend_ops.run_job 244 * when scheduling the job on hardware. We signal the 245 * &drm_sched_fence.finished fence once parent is signalled. 246 */ 247 struct dma_fence *parent; 248 /** 249 * @sched: the scheduler instance to which the job having this struct 250 * belongs to. 251 */ 252 struct drm_gpu_scheduler *sched; 253 /** 254 * @lock: the lock used by the scheduled and the finished fences. 255 */ 256 spinlock_t lock; 257 /** 258 * @owner: job owner for debugging 259 */ 260 void *owner; 261 }; 262 263 struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f); 264 265 /** 266 * struct drm_sched_job - A job to be run by an entity. 267 * 268 * @queue_node: used to append this struct to the queue of jobs in an entity. 269 * @list: a job participates in a "pending" and "done" lists. 270 * @sched: the scheduler instance on which this job is scheduled. 271 * @s_fence: contains the fences for the scheduling of job. 272 * @finish_cb: the callback for the finished fence. 273 * @work: Helper to reschdeule job kill to different context. 274 * @id: a unique id assigned to each job scheduled on the scheduler. 275 * @karma: increment on every hang caused by this job. If this exceeds the hang 276 * limit of the scheduler then the job is marked guilty and will not 277 * be scheduled further. 278 * @s_priority: the priority of the job. 279 * @entity: the entity to which this job belongs. 280 * @cb: the callback for the parent fence in s_fence. 281 * 282 * A job is created by the driver using drm_sched_job_init(), and 283 * should call drm_sched_entity_push_job() once it wants the scheduler 284 * to schedule the job. 285 */ 286 struct drm_sched_job { 287 struct spsc_node queue_node; 288 struct list_head list; 289 struct drm_gpu_scheduler *sched; 290 struct drm_sched_fence *s_fence; 291 292 /* 293 * work is used only after finish_cb has been used and will not be 294 * accessed anymore. 295 */ 296 union { 297 struct dma_fence_cb finish_cb; 298 struct work_struct work; 299 }; 300 301 uint64_t id; 302 atomic_t karma; 303 enum drm_sched_priority s_priority; 304 struct drm_sched_entity *entity; 305 struct dma_fence_cb cb; 306 /** 307 * @dependencies: 308 * 309 * Contains the dependencies as struct dma_fence for this job, see 310 * drm_sched_job_add_dependency() and 311 * drm_sched_job_add_implicit_dependencies(). 312 */ 313 struct xarray dependencies; 314 315 /** @last_dependency: tracks @dependencies as they signal */ 316 unsigned long last_dependency; 317 }; 318 319 static inline bool drm_sched_invalidate_job(struct drm_sched_job *s_job, 320 int threshold) 321 { 322 return s_job && atomic_inc_return(&s_job->karma) > threshold; 323 } 324 325 enum drm_gpu_sched_stat { 326 DRM_GPU_SCHED_STAT_NONE, /* Reserve 0 */ 327 DRM_GPU_SCHED_STAT_NOMINAL, 328 DRM_GPU_SCHED_STAT_ENODEV, 329 }; 330 331 /** 332 * struct drm_sched_backend_ops 333 * 334 * Define the backend operations called by the scheduler, 335 * these functions should be implemented in driver side. 336 */ 337 struct drm_sched_backend_ops { 338 /** 339 * @dependency: 340 * 341 * Called when the scheduler is considering scheduling this job next, to 342 * get another struct dma_fence for this job to block on. Once it 343 * returns NULL, run_job() may be called. 344 * 345 * If a driver exclusively uses drm_sched_job_add_dependency() and 346 * drm_sched_job_add_implicit_dependencies() this can be ommitted and 347 * left as NULL. 348 */ 349 struct dma_fence *(*dependency)(struct drm_sched_job *sched_job, 350 struct drm_sched_entity *s_entity); 351 352 /** 353 * @run_job: Called to execute the job once all of the dependencies 354 * have been resolved. This may be called multiple times, if 355 * timedout_job() has happened and drm_sched_job_recovery() 356 * decides to try it again. 357 */ 358 struct dma_fence *(*run_job)(struct drm_sched_job *sched_job); 359 360 /** 361 * @timedout_job: Called when a job has taken too long to execute, 362 * to trigger GPU recovery. 363 * 364 * This method is called in a workqueue context. 365 * 366 * Drivers typically issue a reset to recover from GPU hangs, and this 367 * procedure usually follows the following workflow: 368 * 369 * 1. Stop the scheduler using drm_sched_stop(). This will park the 370 * scheduler thread and cancel the timeout work, guaranteeing that 371 * nothing is queued while we reset the hardware queue 372 * 2. Try to gracefully stop non-faulty jobs (optional) 373 * 3. Issue a GPU reset (driver-specific) 374 * 4. Re-submit jobs using drm_sched_resubmit_jobs() 375 * 5. Restart the scheduler using drm_sched_start(). At that point, new 376 * jobs can be queued, and the scheduler thread is unblocked 377 * 378 * Note that some GPUs have distinct hardware queues but need to reset 379 * the GPU globally, which requires extra synchronization between the 380 * timeout handler of the different &drm_gpu_scheduler. One way to 381 * achieve this synchronization is to create an ordered workqueue 382 * (using alloc_ordered_workqueue()) at the driver level, and pass this 383 * queue to drm_sched_init(), to guarantee that timeout handlers are 384 * executed sequentially. The above workflow needs to be slightly 385 * adjusted in that case: 386 * 387 * 1. Stop all schedulers impacted by the reset using drm_sched_stop() 388 * 2. Try to gracefully stop non-faulty jobs on all queues impacted by 389 * the reset (optional) 390 * 3. Issue a GPU reset on all faulty queues (driver-specific) 391 * 4. Re-submit jobs on all schedulers impacted by the reset using 392 * drm_sched_resubmit_jobs() 393 * 5. Restart all schedulers that were stopped in step #1 using 394 * drm_sched_start() 395 * 396 * Return DRM_GPU_SCHED_STAT_NOMINAL, when all is normal, 397 * and the underlying driver has started or completed recovery. 398 * 399 * Return DRM_GPU_SCHED_STAT_ENODEV, if the device is no longer 400 * available, i.e. has been unplugged. 401 */ 402 enum drm_gpu_sched_stat (*timedout_job)(struct drm_sched_job *sched_job); 403 404 /** 405 * @free_job: Called once the job's finished fence has been signaled 406 * and it's time to clean it up. 407 */ 408 void (*free_job)(struct drm_sched_job *sched_job); 409 }; 410 411 /** 412 * struct drm_gpu_scheduler 413 * 414 * @ops: backend operations provided by the driver. 415 * @hw_submission_limit: the max size of the hardware queue. 416 * @timeout: the time after which a job is removed from the scheduler. 417 * @name: name of the ring for which this scheduler is being used. 418 * @sched_rq: priority wise array of run queues. 419 * @wake_up_worker: the wait queue on which the scheduler sleeps until a job 420 * is ready to be scheduled. 421 * @job_scheduled: once @drm_sched_entity_do_release is called the scheduler 422 * waits on this wait queue until all the scheduled jobs are 423 * finished. 424 * @hw_rq_count: the number of jobs currently in the hardware queue. 425 * @job_id_count: used to assign unique id to the each job. 426 * @timeout_wq: workqueue used to queue @work_tdr 427 * @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the 428 * timeout interval is over. 429 * @thread: the kthread on which the scheduler which run. 430 * @pending_list: the list of jobs which are currently in the job queue. 431 * @job_list_lock: lock to protect the pending_list. 432 * @hang_limit: once the hangs by a job crosses this limit then it is marked 433 * guilty and it will no longer be considered for scheduling. 434 * @score: score to help loadbalancer pick a idle sched 435 * @_score: score used when the driver doesn't provide one 436 * @ready: marks if the underlying HW is ready to work 437 * @free_guilty: A hit to time out handler to free the guilty job. 438 * 439 * One scheduler is implemented for each hardware ring. 440 */ 441 struct drm_gpu_scheduler { 442 const struct drm_sched_backend_ops *ops; 443 uint32_t hw_submission_limit; 444 long timeout; 445 const char *name; 446 struct drm_sched_rq sched_rq[DRM_SCHED_PRIORITY_COUNT]; 447 wait_queue_head_t wake_up_worker; 448 wait_queue_head_t job_scheduled; 449 atomic_t hw_rq_count; 450 atomic64_t job_id_count; 451 struct workqueue_struct *timeout_wq; 452 struct delayed_work work_tdr; 453 struct task_struct *thread; 454 struct list_head pending_list; 455 spinlock_t job_list_lock; 456 int hang_limit; 457 atomic_t *score; 458 atomic_t _score; 459 bool ready; 460 bool free_guilty; 461 struct device *dev; 462 }; 463 464 int drm_sched_init(struct drm_gpu_scheduler *sched, 465 const struct drm_sched_backend_ops *ops, 466 uint32_t hw_submission, unsigned hang_limit, 467 long timeout, struct workqueue_struct *timeout_wq, 468 atomic_t *score, const char *name, struct device *dev); 469 470 void drm_sched_fini(struct drm_gpu_scheduler *sched); 471 int drm_sched_job_init(struct drm_sched_job *job, 472 struct drm_sched_entity *entity, 473 void *owner); 474 void drm_sched_job_arm(struct drm_sched_job *job); 475 int drm_sched_job_add_dependency(struct drm_sched_job *job, 476 struct dma_fence *fence); 477 int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job, 478 struct drm_gem_object *obj, 479 bool write); 480 481 482 void drm_sched_entity_modify_sched(struct drm_sched_entity *entity, 483 struct drm_gpu_scheduler **sched_list, 484 unsigned int num_sched_list); 485 486 void drm_sched_job_cleanup(struct drm_sched_job *job); 487 void drm_sched_wakeup(struct drm_gpu_scheduler *sched); 488 void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad); 489 void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery); 490 void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched); 491 void drm_sched_resubmit_jobs_ext(struct drm_gpu_scheduler *sched, int max); 492 void drm_sched_increase_karma(struct drm_sched_job *bad); 493 void drm_sched_reset_karma(struct drm_sched_job *bad); 494 void drm_sched_increase_karma_ext(struct drm_sched_job *bad, int type); 495 bool drm_sched_dependency_optimized(struct dma_fence* fence, 496 struct drm_sched_entity *entity); 497 void drm_sched_fault(struct drm_gpu_scheduler *sched); 498 void drm_sched_job_kickout(struct drm_sched_job *s_job); 499 500 void drm_sched_rq_add_entity(struct drm_sched_rq *rq, 501 struct drm_sched_entity *entity); 502 void drm_sched_rq_remove_entity(struct drm_sched_rq *rq, 503 struct drm_sched_entity *entity); 504 505 int drm_sched_entity_init(struct drm_sched_entity *entity, 506 enum drm_sched_priority priority, 507 struct drm_gpu_scheduler **sched_list, 508 unsigned int num_sched_list, 509 atomic_t *guilty); 510 long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout); 511 void drm_sched_entity_fini(struct drm_sched_entity *entity); 512 void drm_sched_entity_destroy(struct drm_sched_entity *entity); 513 void drm_sched_entity_select_rq(struct drm_sched_entity *entity); 514 struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity); 515 void drm_sched_entity_push_job(struct drm_sched_job *sched_job); 516 void drm_sched_entity_set_priority(struct drm_sched_entity *entity, 517 enum drm_sched_priority priority); 518 bool drm_sched_entity_is_ready(struct drm_sched_entity *entity); 519 520 struct drm_sched_fence *drm_sched_fence_alloc( 521 struct drm_sched_entity *s_entity, void *owner); 522 void drm_sched_fence_init(struct drm_sched_fence *fence, 523 struct drm_sched_entity *entity); 524 void drm_sched_fence_free(struct drm_sched_fence *fence); 525 526 void drm_sched_fence_scheduled(struct drm_sched_fence *fence); 527 void drm_sched_fence_finished(struct drm_sched_fence *fence); 528 529 unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched); 530 void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched, 531 unsigned long remaining); 532 struct drm_gpu_scheduler * 533 drm_sched_pick_best(struct drm_gpu_scheduler **sched_list, 534 unsigned int num_sched_list); 535 536 #endif 537