/* * Copyright 2015 Advanced Micro Devices, Inc. * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR * OTHER DEALINGS IN THE SOFTWARE. * */ /** * DOC: Overview * * The GPU scheduler provides entities which allow userspace to push jobs * into software queues which are then scheduled on a hardware run queue. * The software queues have a priority among them. The scheduler selects the entities * from the run queue using a FIFO. The scheduler provides dependency handling * features among jobs. The driver is supposed to provide callback functions for * backend operations to the scheduler like submitting a job to hardware run queue, * returning the dependencies of a job etc. * * The organisation of the scheduler is the following: * * 1. Each hw run queue has one scheduler * 2. Each scheduler has multiple run queues with different priorities * (e.g., HIGH_HW,HIGH_SW, KERNEL, NORMAL) * 3. Each scheduler run queue has a queue of entities to schedule * 4. Entities themselves maintain a queue of jobs that will be scheduled on * the hardware. * * The jobs in a entity are always scheduled in the order that they were pushed. */ #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include "gpu_scheduler_trace.h" #define to_drm_sched_job(sched_job) \ container_of((sched_job), struct drm_sched_job, queue_node) static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb); /** * drm_sched_rq_init - initialize a given run queue struct * * @rq: scheduler run queue * * Initializes a scheduler runqueue. */ static void drm_sched_rq_init(struct drm_gpu_scheduler *sched, struct drm_sched_rq *rq) { spin_lock_init(&rq->lock); INIT_LIST_HEAD(&rq->entities); rq->current_entity = NULL; rq->sched = sched; } /** * drm_sched_rq_add_entity - add an entity * * @rq: scheduler run queue * @entity: scheduler entity * * Adds a scheduler entity to the run queue. */ void drm_sched_rq_add_entity(struct drm_sched_rq *rq, struct drm_sched_entity *entity) { if (!list_empty(&entity->list)) return; spin_lock(&rq->lock); list_add_tail(&entity->list, &rq->entities); spin_unlock(&rq->lock); } /** * drm_sched_rq_remove_entity - remove an entity * * @rq: scheduler run queue * @entity: scheduler entity * * Removes a scheduler entity from the run queue. */ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq, struct drm_sched_entity *entity) { if (list_empty(&entity->list)) return; spin_lock(&rq->lock); list_del_init(&entity->list); if (rq->current_entity == entity) rq->current_entity = NULL; spin_unlock(&rq->lock); } /** * drm_sched_rq_select_entity - Select an entity which could provide a job to run * * @rq: scheduler run queue to check. * * Try to find a ready entity, returns NULL if none found. */ static struct drm_sched_entity * drm_sched_rq_select_entity(struct drm_sched_rq *rq) { struct drm_sched_entity *entity; spin_lock(&rq->lock); entity = rq->current_entity; if (entity) { list_for_each_entry_continue(entity, &rq->entities, list) { if (drm_sched_entity_is_ready(entity)) { rq->current_entity = entity; reinit_completion(&entity->entity_idle); spin_unlock(&rq->lock); return entity; } } } list_for_each_entry(entity, &rq->entities, list) { if (drm_sched_entity_is_ready(entity)) { rq->current_entity = entity; reinit_completion(&entity->entity_idle); spin_unlock(&rq->lock); return entity; } if (entity == rq->current_entity) break; } spin_unlock(&rq->lock); return NULL; } /** * drm_sched_dependency_optimized * * @fence: the dependency fence * @entity: the entity which depends on the above fence * * Returns true if the dependency can be optimized and false otherwise */ bool drm_sched_dependency_optimized(struct dma_fence* fence, struct drm_sched_entity *entity) { struct drm_gpu_scheduler *sched = entity->rq->sched; struct drm_sched_fence *s_fence; if (!fence || dma_fence_is_signaled(fence)) return false; if (fence->context == entity->fence_context) return true; s_fence = to_drm_sched_fence(fence); if (s_fence && s_fence->sched == sched) return true; return false; } EXPORT_SYMBOL(drm_sched_dependency_optimized); /** * drm_sched_start_timeout - start timeout for reset worker * * @sched: scheduler instance to start the worker for * * Start the timeout for the given scheduler. */ static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched) { if (sched->timeout != MAX_SCHEDULE_TIMEOUT && !list_empty(&sched->ring_mirror_list)) schedule_delayed_work(&sched->work_tdr, sched->timeout); } /** * drm_sched_fault - immediately start timeout handler * * @sched: scheduler where the timeout handling should be started. * * Start timeout handling immediately when the driver detects a hardware fault. */ void drm_sched_fault(struct drm_gpu_scheduler *sched) { mod_delayed_work(system_wq, &sched->work_tdr, 0); } EXPORT_SYMBOL(drm_sched_fault); /** * drm_sched_suspend_timeout - Suspend scheduler job timeout * * @sched: scheduler instance for which to suspend the timeout * * Suspend the delayed work timeout for the scheduler. This is done by * modifying the delayed work timeout to an arbitrary large value, * MAX_SCHEDULE_TIMEOUT in this case. * * Returns the timeout remaining * */ unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched) { unsigned long sched_timeout, now = jiffies; sched_timeout = sched->work_tdr.timer.expires; /* * Modify the timeout to an arbitrarily large value. This also prevents * the timeout to be restarted when new submissions arrive */ if (mod_delayed_work(system_wq, &sched->work_tdr, MAX_SCHEDULE_TIMEOUT) && time_after(sched_timeout, now)) return sched_timeout - now; else return sched->timeout; } EXPORT_SYMBOL(drm_sched_suspend_timeout); /** * drm_sched_resume_timeout - Resume scheduler job timeout * * @sched: scheduler instance for which to resume the timeout * @remaining: remaining timeout * * Resume the delayed work timeout for the scheduler. */ void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched, unsigned long remaining) { spin_lock(&sched->job_list_lock); if (list_empty(&sched->ring_mirror_list)) cancel_delayed_work(&sched->work_tdr); else mod_delayed_work(system_wq, &sched->work_tdr, remaining); spin_unlock(&sched->job_list_lock); } EXPORT_SYMBOL(drm_sched_resume_timeout); static void drm_sched_job_begin(struct drm_sched_job *s_job) { struct drm_gpu_scheduler *sched = s_job->sched; spin_lock(&sched->job_list_lock); list_add_tail(&s_job->node, &sched->ring_mirror_list); drm_sched_start_timeout(sched); spin_unlock(&sched->job_list_lock); } static void drm_sched_job_timedout(struct work_struct *work) { struct drm_gpu_scheduler *sched; struct drm_sched_job *job; sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work); /* Protects against concurrent deletion in drm_sched_get_cleanup_job */ spin_lock(&sched->job_list_lock); job = list_first_entry_or_null(&sched->ring_mirror_list, struct drm_sched_job, node); if (job) { /* * Remove the bad job so it cannot be freed by concurrent * drm_sched_cleanup_jobs. It will be reinserted back after sched->thread * is parked at which point it's safe. */ list_del_init(&job->node); spin_unlock(&sched->job_list_lock); job->sched->ops->timedout_job(job); /* * Guilty job did complete and hence needs to be manually removed * See drm_sched_stop doc. */ if (sched->free_guilty) { job->sched->ops->free_job(job); sched->free_guilty = false; } } else { spin_unlock(&sched->job_list_lock); } spin_lock(&sched->job_list_lock); drm_sched_start_timeout(sched); spin_unlock(&sched->job_list_lock); } /** * drm_sched_increase_karma - Update sched_entity guilty flag * * @bad: The job guilty of time out * * Increment on every hang caused by the 'bad' job. If this exceeds the hang * limit of the scheduler then the respective sched entity is marked guilty and * jobs from it will not be scheduled further */ void drm_sched_increase_karma(struct drm_sched_job *bad) { int i; struct drm_sched_entity *tmp; struct drm_sched_entity *entity; struct drm_gpu_scheduler *sched = bad->sched; /* don't increase @bad's karma if it's from KERNEL RQ, * because sometimes GPU hang would cause kernel jobs (like VM updating jobs) * corrupt but keep in mind that kernel jobs always considered good. */ if (bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) { atomic_inc(&bad->karma); for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_KERNEL; i++) { struct drm_sched_rq *rq = &sched->sched_rq[i]; spin_lock(&rq->lock); list_for_each_entry_safe(entity, tmp, &rq->entities, list) { if (bad->s_fence->scheduled.context == entity->fence_context) { if (atomic_read(&bad->karma) > bad->sched->hang_limit) if (entity->guilty) atomic_set(entity->guilty, 1); break; } } spin_unlock(&rq->lock); if (&entity->list != &rq->entities) break; } } } EXPORT_SYMBOL(drm_sched_increase_karma); /** * drm_sched_stop - stop the scheduler * * @sched: scheduler instance * @bad: job which caused the time out * * Stop the scheduler and also removes and frees all completed jobs. * Note: bad job will not be freed as it might be used later and so it's * callers responsibility to release it manually if it's not part of the * mirror list any more. * */ void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad) { struct drm_sched_job *s_job, *tmp; kthread_park(sched->thread); /* * Reinsert back the bad job here - now it's safe as * drm_sched_get_cleanup_job cannot race against us and release the * bad job at this point - we parked (waited for) any in progress * (earlier) cleanups and drm_sched_get_cleanup_job will not be called * now until the scheduler thread is unparked. */ if (bad && bad->sched == sched) /* * Add at the head of the queue to reflect it was the earliest * job extracted. */ list_add(&bad->node, &sched->ring_mirror_list); /* * Iterate the job list from later to earlier one and either deactive * their HW callbacks or remove them from mirror list if they already * signaled. * This iteration is thread safe as sched thread is stopped. */ list_for_each_entry_safe_reverse(s_job, tmp, &sched->ring_mirror_list, node) { if (s_job->s_fence->parent && dma_fence_remove_callback(s_job->s_fence->parent, &s_job->cb)) { atomic_dec(&sched->hw_rq_count); } else { /* * remove job from ring_mirror_list. * Locking here is for concurrent resume timeout */ spin_lock(&sched->job_list_lock); list_del_init(&s_job->node); spin_unlock(&sched->job_list_lock); /* * Wait for job's HW fence callback to finish using s_job * before releasing it. * * Job is still alive so fence refcount at least 1 */ dma_fence_wait(&s_job->s_fence->finished, false); /* * We must keep bad job alive for later use during * recovery by some of the drivers but leave a hint * that the guilty job must be released. */ if (bad != s_job) sched->ops->free_job(s_job); else sched->free_guilty = true; } } /* * Stop pending timer in flight as we rearm it in drm_sched_start. This * avoids the pending timeout work in progress to fire right away after * this TDR finished and before the newly restarted jobs had a * chance to complete. */ cancel_delayed_work(&sched->work_tdr); } EXPORT_SYMBOL(drm_sched_stop); /** * drm_sched_job_recovery - recover jobs after a reset * * @sched: scheduler instance * @full_recovery: proceed with complete sched restart * */ void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery) { struct drm_sched_job *s_job, *tmp; int r; /* * Locking the list is not required here as the sched thread is parked * so no new jobs are being inserted or removed. Also concurrent * GPU recovers can't run in parallel. */ list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) { struct dma_fence *fence = s_job->s_fence->parent; atomic_inc(&sched->hw_rq_count); if (!full_recovery) continue; if (fence) { r = dma_fence_add_callback(fence, &s_job->cb, drm_sched_process_job); if (r == -ENOENT) drm_sched_process_job(fence, &s_job->cb); else if (r) DRM_ERROR("fence add callback failed (%d)\n", r); } else drm_sched_process_job(NULL, &s_job->cb); } if (full_recovery) { spin_lock(&sched->job_list_lock); drm_sched_start_timeout(sched); spin_unlock(&sched->job_list_lock); } kthread_unpark(sched->thread); } EXPORT_SYMBOL(drm_sched_start); /** * drm_sched_resubmit_jobs - helper to relunch job from mirror ring list * * @sched: scheduler instance * */ void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched) { struct drm_sched_job *s_job, *tmp; uint64_t guilty_context; bool found_guilty = false; struct dma_fence *fence; list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) { struct drm_sched_fence *s_fence = s_job->s_fence; if (!found_guilty && atomic_read(&s_job->karma) > sched->hang_limit) { found_guilty = true; guilty_context = s_job->s_fence->scheduled.context; } if (found_guilty && s_job->s_fence->scheduled.context == guilty_context) dma_fence_set_error(&s_fence->finished, -ECANCELED); dma_fence_put(s_job->s_fence->parent); fence = sched->ops->run_job(s_job); if (IS_ERR_OR_NULL(fence)) { if (IS_ERR(fence)) dma_fence_set_error(&s_fence->finished, PTR_ERR(fence)); s_job->s_fence->parent = NULL; } else { s_job->s_fence->parent = fence; } } } EXPORT_SYMBOL(drm_sched_resubmit_jobs); /** * drm_sched_job_init - init a scheduler job * * @job: scheduler job to init * @entity: scheduler entity to use * @owner: job owner for debugging * * Refer to drm_sched_entity_push_job() documentation * for locking considerations. * * Returns 0 for success, negative error code otherwise. */ int drm_sched_job_init(struct drm_sched_job *job, struct drm_sched_entity *entity, void *owner) { struct drm_gpu_scheduler *sched; drm_sched_entity_select_rq(entity); if (!entity->rq) return -ENOENT; sched = entity->rq->sched; job->sched = sched; job->entity = entity; job->s_priority = entity->rq - sched->sched_rq; job->s_fence = drm_sched_fence_create(entity, owner); if (!job->s_fence) return -ENOMEM; job->id = atomic64_inc_return(&sched->job_id_count); INIT_LIST_HEAD(&job->node); return 0; } EXPORT_SYMBOL(drm_sched_job_init); /** * drm_sched_job_cleanup - clean up scheduler job resources * * @job: scheduler job to clean up */ void drm_sched_job_cleanup(struct drm_sched_job *job) { dma_fence_put(&job->s_fence->finished); job->s_fence = NULL; } EXPORT_SYMBOL(drm_sched_job_cleanup); /** * drm_sched_ready - is the scheduler ready * * @sched: scheduler instance * * Return true if we can push more jobs to the hw, otherwise false. */ static bool drm_sched_ready(struct drm_gpu_scheduler *sched) { return atomic_read(&sched->hw_rq_count) < sched->hw_submission_limit; } /** * drm_sched_wakeup - Wake up the scheduler when it is ready * * @sched: scheduler instance * */ void drm_sched_wakeup(struct drm_gpu_scheduler *sched) { if (drm_sched_ready(sched)) wake_up_interruptible(&sched->wake_up_worker); } /** * drm_sched_select_entity - Select next entity to process * * @sched: scheduler instance * * Returns the entity to process or NULL if none are found. */ static struct drm_sched_entity * drm_sched_select_entity(struct drm_gpu_scheduler *sched) { struct drm_sched_entity *entity; int i; if (!drm_sched_ready(sched)) return NULL; /* Kernel run queue has higher priority than normal run queue*/ for (i = DRM_SCHED_PRIORITY_MAX - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) { entity = drm_sched_rq_select_entity(&sched->sched_rq[i]); if (entity) break; } return entity; } /** * drm_sched_process_job - process a job * * @f: fence * @cb: fence callbacks * * Called after job has finished execution. */ static void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb) { struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb); struct drm_sched_fence *s_fence = s_job->s_fence; struct drm_gpu_scheduler *sched = s_fence->sched; atomic_dec(&sched->hw_rq_count); atomic_dec(&sched->num_jobs); trace_drm_sched_process_job(s_fence); dma_fence_get(&s_fence->finished); drm_sched_fence_finished(s_fence); dma_fence_put(&s_fence->finished); wake_up_interruptible(&sched->wake_up_worker); } /** * drm_sched_get_cleanup_job - fetch the next finished job to be destroyed * * @sched: scheduler instance * * Returns the next finished job from the mirror list (if there is one) * ready for it to be destroyed. */ static struct drm_sched_job * drm_sched_get_cleanup_job(struct drm_gpu_scheduler *sched) { struct drm_sched_job *job; /* * Don't destroy jobs while the timeout worker is running OR thread * is being parked and hence assumed to not touch ring_mirror_list */ if ((sched->timeout != MAX_SCHEDULE_TIMEOUT && !cancel_delayed_work(&sched->work_tdr)) || kthread_should_park()) return NULL; spin_lock(&sched->job_list_lock); job = list_first_entry_or_null(&sched->ring_mirror_list, struct drm_sched_job, node); if (job && dma_fence_is_signaled(&job->s_fence->finished)) { /* remove job from ring_mirror_list */ list_del_init(&job->node); } else { job = NULL; /* queue timeout for next job */ drm_sched_start_timeout(sched); } spin_unlock(&sched->job_list_lock); return job; } /** * drm_sched_pick_best - Get a drm sched from a sched_list with the least load * @sched_list: list of drm_gpu_schedulers * @num_sched_list: number of drm_gpu_schedulers in the sched_list * * Returns pointer of the sched with the least load or NULL if none of the * drm_gpu_schedulers are ready */ struct drm_gpu_scheduler * drm_sched_pick_best(struct drm_gpu_scheduler **sched_list, unsigned int num_sched_list) { struct drm_gpu_scheduler *sched, *picked_sched = NULL; int i; unsigned int min_jobs = UINT_MAX, num_jobs; for (i = 0; i < num_sched_list; ++i) { sched = sched_list[i]; if (!sched->ready) { DRM_WARN("scheduler %s is not ready, skipping", sched->name); continue; } num_jobs = atomic_read(&sched->num_jobs); if (num_jobs < min_jobs) { min_jobs = num_jobs; picked_sched = sched; } } return picked_sched; } EXPORT_SYMBOL(drm_sched_pick_best); /** * drm_sched_blocked - check if the scheduler is blocked * * @sched: scheduler instance * * Returns true if blocked, otherwise false. */ static bool drm_sched_blocked(struct drm_gpu_scheduler *sched) { if (kthread_should_park()) { kthread_parkme(); return true; } return false; } /** * drm_sched_main - main scheduler thread * * @param: scheduler instance * * Returns 0. */ static int drm_sched_main(void *param) { struct sched_param sparam = {.sched_priority = 1}; struct drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param; int r; sched_setscheduler(current, SCHED_FIFO, &sparam); while (!kthread_should_stop()) { struct drm_sched_entity *entity = NULL; struct drm_sched_fence *s_fence; struct drm_sched_job *sched_job; struct dma_fence *fence; struct drm_sched_job *cleanup_job = NULL; wait_event_interruptible(sched->wake_up_worker, (cleanup_job = drm_sched_get_cleanup_job(sched)) || (!drm_sched_blocked(sched) && (entity = drm_sched_select_entity(sched))) || kthread_should_stop()); if (cleanup_job) { sched->ops->free_job(cleanup_job); /* queue timeout for next job */ drm_sched_start_timeout(sched); } if (!entity) continue; sched_job = drm_sched_entity_pop_job(entity); complete(&entity->entity_idle); if (!sched_job) continue; s_fence = sched_job->s_fence; atomic_inc(&sched->hw_rq_count); drm_sched_job_begin(sched_job); trace_drm_run_job(sched_job, entity); fence = sched->ops->run_job(sched_job); drm_sched_fence_scheduled(s_fence); if (!IS_ERR_OR_NULL(fence)) { s_fence->parent = dma_fence_get(fence); r = dma_fence_add_callback(fence, &sched_job->cb, drm_sched_process_job); if (r == -ENOENT) drm_sched_process_job(fence, &sched_job->cb); else if (r) DRM_ERROR("fence add callback failed (%d)\n", r); dma_fence_put(fence); } else { if (IS_ERR(fence)) dma_fence_set_error(&s_fence->finished, PTR_ERR(fence)); drm_sched_process_job(NULL, &sched_job->cb); } wake_up(&sched->job_scheduled); } return 0; } /** * drm_sched_init - Init a gpu scheduler instance * * @sched: scheduler instance * @ops: backend operations for this scheduler * @hw_submission: number of hw submissions that can be in flight * @hang_limit: number of times to allow a job to hang before dropping it * @timeout: timeout value in jiffies for the scheduler * @name: name used for debugging * * Return 0 on success, otherwise error code. */ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_backend_ops *ops, unsigned hw_submission, unsigned hang_limit, long timeout, const char *name) { int i, ret; sched->ops = ops; sched->hw_submission_limit = hw_submission; sched->name = name; sched->timeout = timeout; sched->hang_limit = hang_limit; for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_MAX; i++) drm_sched_rq_init(sched, &sched->sched_rq[i]); init_waitqueue_head(&sched->wake_up_worker); init_waitqueue_head(&sched->job_scheduled); INIT_LIST_HEAD(&sched->ring_mirror_list); spin_lock_init(&sched->job_list_lock); atomic_set(&sched->hw_rq_count, 0); INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout); atomic_set(&sched->num_jobs, 0); atomic64_set(&sched->job_id_count, 0); /* Each scheduler will run on a seperate kernel thread */ sched->thread = kthread_run(drm_sched_main, sched, sched->name); if (IS_ERR(sched->thread)) { ret = PTR_ERR(sched->thread); sched->thread = NULL; DRM_ERROR("Failed to create scheduler for %s.\n", name); return ret; } sched->ready = true; return 0; } EXPORT_SYMBOL(drm_sched_init); /** * drm_sched_fini - Destroy a gpu scheduler * * @sched: scheduler instance * * Tears down and cleans up the scheduler. */ void drm_sched_fini(struct drm_gpu_scheduler *sched) { if (sched->thread) kthread_stop(sched->thread); sched->ready = false; } EXPORT_SYMBOL(drm_sched_fini);