drivers/gpu/drm/amd/scheduler/gpu_scheduler.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/wait.h>
  26 #include <linux/sched.h>
  27 #include <drm/drmP.h>
  28 #include "gpu_scheduler.h"
  29
  30 /* Initialize a given run queue struct */
  31 static void amd_sched_rq_init(struct amd_sched_rq *rq)
  32 {
  33         spin_lock_init(&rq->lock);
  34         INIT_LIST_HEAD(&rq->entities);
  35         rq->current_entity = NULL;
  36 }
  37
  38 static void amd_sched_rq_add_entity(struct amd_sched_rq *rq,
  39                                     struct amd_sched_entity *entity)
  40 {
  41         spin_lock(&rq->lock);
  42         list_add_tail(&entity->list, &rq->entities);
  43         spin_unlock(&rq->lock);
  44 }
  45
  46 static void amd_sched_rq_remove_entity(struct amd_sched_rq *rq,
  47                                        struct amd_sched_entity *entity)
  48 {
  49         spin_lock(&rq->lock);
  50         list_del_init(&entity->list);
  51         if (rq->current_entity == entity)
  52                 rq->current_entity = NULL;
  53         spin_unlock(&rq->lock);
  54 }
  55
  56 /**
  57  * Select next entity from a specified run queue with round robin policy.
  58  * It could return the same entity as current one if current is the only
  59  * available one in the queue. Return NULL if nothing available.
  60  */
  61 static struct amd_sched_entity *
  62 amd_sched_rq_select_entity(struct amd_sched_rq *rq)
  63 {
  64         struct amd_sched_entity *entity;
  65
  66         spin_lock(&rq->lock);
  67
  68         entity = rq->current_entity;
  69         if (entity) {
  70                 list_for_each_entry_continue(entity, &rq->entities, list) {
  71                         if (!kfifo_is_empty(&entity->job_queue)) {
  72                                 rq->current_entity = entity;
  73                                 spin_unlock(&rq->lock);
  74                                 return rq->current_entity;
  75                         }
  76                 }
  77         }
  78
  79         list_for_each_entry(entity, &rq->entities, list) {
  80
  81                 if (!kfifo_is_empty(&entity->job_queue)) {
  82                         rq->current_entity = entity;
  83                         spin_unlock(&rq->lock);
  84                         return rq->current_entity;
  85                 }
  86
  87                 if (entity == rq->current_entity)
  88                         break;
  89         }
  90
  91         spin_unlock(&rq->lock);
  92
  93         return NULL;
  94 }
  95
  96 /**
  97  * Init a context entity used by scheduler when submit to HW ring.
  98  *
  99  * @sched       The pointer to the scheduler
 100  * @entity      The pointer to a valid amd_sched_entity
 101  * @rq          The run queue this entity belongs
 102  * @kernel      If this is an entity for the kernel
 103  * @jobs        The max number of jobs in the job queue
 104  *
 105  * return 0 if succeed. negative error code on failure
 106 */
 107 int amd_sched_entity_init(struct amd_gpu_scheduler *sched,
 108                           struct amd_sched_entity *entity,
 109                           struct amd_sched_rq *rq,
 110                           uint32_t jobs)
 111 {
 112         char name[20];
 113
 114         if (!(sched && entity && rq))
 115                 return -EINVAL;
 116
 117         memset(entity, 0, sizeof(struct amd_sched_entity));
 118         entity->belongto_rq = rq;
 119         entity->scheduler = sched;
 120         init_waitqueue_head(&entity->wait_queue);
 121         entity->fence_context = fence_context_alloc(1);
 122         snprintf(name, sizeof(name), "c_entity[%llu]", entity->fence_context);
 123         memcpy(entity->name, name, 20);
 124         entity->need_wakeup = false;
 125         if(kfifo_alloc(&entity->job_queue,
 126                        jobs * sizeof(void *),
 127                        GFP_KERNEL))
 128                 return -EINVAL;
 129
 130         spin_lock_init(&entity->queue_lock);
 131         atomic_set(&entity->fence_seq, 0);
 132
 133         /* Add the entity to the run queue */
 134         amd_sched_rq_add_entity(rq, entity);
 135         return 0;
 136 }
 137
 138 /**
 139  * Query if entity is initialized
 140  *
 141  * @sched       Pointer to scheduler instance
 142  * @entity      The pointer to a valid scheduler entity
 143  *
 144  * return true if entity is initialized, false otherwise
 145 */
 146 static bool amd_sched_entity_is_initialized(struct amd_gpu_scheduler *sched,
 147                                             struct amd_sched_entity *entity)
 148 {
 149         return entity->scheduler == sched &&
 150                 entity->belongto_rq != NULL;
 151 }
 152
 153 /**
 154  * Check if entity is idle
 155  *
 156  * @entity      The pointer to a valid scheduler entity
 157  *
 158  * Return true if entity don't has any unscheduled jobs.
 159  */
 160 static bool amd_sched_entity_is_idle(struct amd_sched_entity *entity)
 161 {
 162         rmb();
 163         if (kfifo_is_empty(&entity->job_queue))
 164                 return true;
 165
 166         return false;
 167 }
 168
 169 /**
 170  * Destroy a context entity
 171  *
 172  * @sched       Pointer to scheduler instance
 173  * @entity      The pointer to a valid scheduler entity
 174  *
 175  * return 0 if succeed. negative error code on failure
 176  */
 177 int amd_sched_entity_fini(struct amd_gpu_scheduler *sched,
 178                             struct amd_sched_entity *entity)
 179 {
 180         struct amd_sched_rq *rq = entity->belongto_rq;
 181         long r;
 182
 183         if (!amd_sched_entity_is_initialized(sched, entity))
 184                 return 0;
 185         entity->need_wakeup = true;
 186         /**
 187          * The client will not queue more IBs during this fini, consume existing
 188          * queued IBs
 189         */
 190         r = wait_event_timeout(entity->wait_queue,
 191                 amd_sched_entity_is_idle(entity),
 192                 msecs_to_jiffies(AMD_GPU_WAIT_IDLE_TIMEOUT_IN_MS));
 193
 194         if (r <= 0)
 195                 DRM_INFO("Entity %p is in waiting state during fini\n",
 196                          entity);
 197
 198         amd_sched_rq_remove_entity(rq, entity);
 199         kfifo_free(&entity->job_queue);
 200         return r;
 201 }
 202
 203 /**
 204  * Submit a normal job to the job queue
 205  *
 206  * @sched       The pointer to the scheduler
 207  * @c_entity    The pointer to amd_sched_entity
 208  * @job         The pointer to job required to submit
 209  * return 0 if succeed. -1 if failed.
 210  *        -2 indicate queue is full for this client, client should wait untill
 211  *           scheduler consum some queued command.
 212  *        -1 other fail.
 213 */
 214 int amd_sched_push_job(struct amd_sched_job *sched_job)
 215 {
 216         struct amd_sched_fence  *fence =
 217                 amd_sched_fence_create(sched_job->s_entity);
 218         if (!fence)
 219                 return -EINVAL;
 220         fence_get(&fence->base);
 221         sched_job->s_fence = fence;
 222         while (kfifo_in_spinlocked(&sched_job->s_entity->job_queue,
 223                                    &sched_job, sizeof(void *),
 224                                    &sched_job->s_entity->queue_lock) !=
 225                sizeof(void *)) {
 226                 /**
 227                  * Current context used up all its IB slots
 228                  * wait here, or need to check whether GPU is hung
 229                 */
 230                 schedule();
 231         }
 232         /* first job wake up scheduler */
 233         if ((kfifo_len(&sched_job->s_entity->job_queue) / sizeof(void *)) == 1)
 234                 wake_up_interruptible(&sched_job->sched->wait_queue);
 235         return 0;
 236 }
 237
 238 /**
 239  * Return ture if we can push more jobs to the hw.
 240  */
 241 static bool amd_sched_ready(struct amd_gpu_scheduler *sched)
 242 {
 243         return atomic_read(&sched->hw_rq_count) <
 244                 sched->hw_submission_limit;
 245 }
 246
 247 /**
 248  * Select next entity containing real IB submissions
 249 */
 250 static struct amd_sched_entity *
 251 amd_sched_select_context(struct amd_gpu_scheduler *sched)
 252 {
 253         struct amd_sched_entity *tmp;
 254
 255         if (!amd_sched_ready(sched))
 256                 return NULL;
 257
 258         /* Kernel run queue has higher priority than normal run queue*/
 259         tmp = amd_sched_rq_select_entity(&sched->kernel_rq);
 260         if (tmp == NULL)
 261                 tmp = amd_sched_rq_select_entity(&sched->sched_rq);
 262
 263         return tmp;
 264 }
 265
 266 static void amd_sched_process_job(struct fence *f, struct fence_cb *cb)
 267 {
 268         struct amd_sched_job *sched_job =
 269                 container_of(cb, struct amd_sched_job, cb);
 270         struct amd_gpu_scheduler *sched;
 271
 272         sched = sched_job->sched;
 273         amd_sched_fence_signal(sched_job->s_fence);
 274         atomic_dec(&sched->hw_rq_count);
 275         fence_put(&sched_job->s_fence->base);
 276         sched->ops->process_job(sched, sched_job);
 277         wake_up_interruptible(&sched->wait_queue);
 278 }
 279
 280 static int amd_sched_main(void *param)
 281 {
 282         struct sched_param sparam = {.sched_priority = 1};
 283         struct amd_gpu_scheduler *sched = (struct amd_gpu_scheduler *)param;
 284         int r;
 285
 286         sched_setscheduler(current, SCHED_FIFO, &sparam);
 287
 288         while (!kthread_should_stop()) {
 289                 struct amd_sched_entity *c_entity = NULL;
 290                 struct amd_sched_job *job;
 291                 struct fence *fence;
 292
 293                 wait_event_interruptible(sched->wait_queue,
 294                         kthread_should_stop() ||
 295                         (c_entity = amd_sched_select_context(sched)));
 296
 297                 if (!c_entity)
 298                         continue;
 299
 300                 r = kfifo_out(&c_entity->job_queue, &job, sizeof(void *));
 301                 if (r != sizeof(void *))
 302                         continue;
 303                 r = 0;
 304                 if (sched->ops->prepare_job)
 305                         r = sched->ops->prepare_job(sched, c_entity, job);
 306                 if (!r) {
 307                         atomic_inc(&sched->hw_rq_count);
 308                 }
 309                 mutex_lock(&sched->sched_lock);
 310                 fence = sched->ops->run_job(sched, c_entity, job);
 311                 if (fence) {
 312                         r = fence_add_callback(fence, &job->cb,
 313                                                amd_sched_process_job);
 314                         if (r == -ENOENT)
 315                                 amd_sched_process_job(fence, &job->cb);
 316                         else if (r)
 317                                 DRM_ERROR("fence add callback failed (%d)\n", r);
 318                         fence_put(fence);
 319                 }
 320                 mutex_unlock(&sched->sched_lock);
 321
 322                 if (c_entity->need_wakeup) {
 323                         c_entity->need_wakeup = false;
 324                         wake_up(&c_entity->wait_queue);
 325                 }
 326
 327         }
 328         return 0;
 329 }
 330
 331 /**
 332  * Create a gpu scheduler
 333  *
 334  * @device      The device context for this scheduler
 335  * @ops         The backend operations for this scheduler.
 336  * @id          The scheduler is per ring, here is ring id.
 337  * @granularity The minumum ms unit the scheduler will scheduled.
 338  * @preemption  Indicate whether this ring support preemption, 0 is no.
 339  *
 340  * return the pointer to scheduler for success, otherwise return NULL
 341 */
 342 struct amd_gpu_scheduler *amd_sched_create(void *device,
 343                                            struct amd_sched_backend_ops *ops,
 344                                            unsigned ring,
 345                                            unsigned granularity,
 346                                            unsigned preemption,
 347                                            unsigned hw_submission)
 348 {
 349         struct amd_gpu_scheduler *sched;
 350         char name[20];
 351
 352         sched = kzalloc(sizeof(struct amd_gpu_scheduler), GFP_KERNEL);
 353         if (!sched)
 354                 return NULL;
 355
 356         sched->device = device;
 357         sched->ops = ops;
 358         sched->granularity = granularity;
 359         sched->ring_id = ring;
 360         sched->preemption = preemption;
 361         sched->hw_submission_limit = hw_submission;
 362         snprintf(name, sizeof(name), "gpu_sched[%d]", ring);
 363         mutex_init(&sched->sched_lock);
 364         amd_sched_rq_init(&sched->sched_rq);
 365         amd_sched_rq_init(&sched->kernel_rq);
 366
 367         init_waitqueue_head(&sched->wait_queue);
 368         atomic_set(&sched->hw_rq_count, 0);
 369         /* Each scheduler will run on a seperate kernel thread */
 370         sched->thread = kthread_run(amd_sched_main, sched, name);
 371         if (IS_ERR(sched->thread)) {
 372                 DRM_ERROR("Failed to create scheduler for id %d.\n", ring);
 373                 kfree(sched);
 374                 return NULL;
 375         }
 376
 377         return sched;
 378 }
 379
 380 /**
 381  * Destroy a gpu scheduler
 382  *
 383  * @sched       The pointer to the scheduler
 384  *
 385  * return 0 if succeed. -1 if failed.
 386  */
 387 int amd_sched_destroy(struct amd_gpu_scheduler *sched)
 388 {
 389         kthread_stop(sched->thread);
 390         kfree(sched);
 391         return  0;
 392 }