/* * 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 an entity are always scheduled in the order in which they were pushed. * * Note that once a job was taken from the entities queue and pushed to the * hardware, i.e. the pending queue, the entity must not be referenced anymore * through the jobs entity pointer. */ /** * DOC: Flow Control * * The DRM GPU scheduler provides a flow control mechanism to regulate the rate * in which the jobs fetched from scheduler entities are executed. * * In this context the &drm_gpu_scheduler keeps track of a driver specified * credit limit representing the capacity of this scheduler and a credit count; * every &drm_sched_job carries a driver specified number of credits. * * Once a job is executed (but not yet finished), the job's credits contribute * to the scheduler's credit count until the job is finished. If by executing * one more job the scheduler's credit count would exceed the scheduler's * credit limit, the job won't be executed. Instead, the scheduler will wait * until the credit count has decreased enough to not overflow its credit limit. * This implies waiting for previously executed jobs. * * Optionally, drivers may register a callback (update_job_credits) provided by * struct drm_sched_backend_ops to update the job's credits dynamically. The * scheduler executes this callback every time the scheduler considers a job for * execution and subsequently checks whether the job fits the scheduler's credit * limit. */ #include #include #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include "gpu_scheduler_trace.h" #ifdef CONFIG_LOCKDEP static struct lockdep_map drm_sched_lockdep_map = { .name = "drm_sched_lockdep_map" }; #endif #define to_drm_sched_job(sched_job) \ container_of((sched_job), struct drm_sched_job, queue_node) int drm_sched_policy = DRM_SCHED_POLICY_FIFO; /** * DOC: sched_policy (int) * Used to override default entities scheduling policy in a run queue. */ MODULE_PARM_DESC(sched_policy, "Specify the scheduling policy for entities on a run-queue, " __stringify(DRM_SCHED_POLICY_RR) " = Round Robin, " __stringify(DRM_SCHED_POLICY_FIFO) " = FIFO (default)."); module_param_named(sched_policy, drm_sched_policy, int, 0444); static u32 drm_sched_available_credits(struct drm_gpu_scheduler *sched) { u32 credits; drm_WARN_ON(sched, check_sub_overflow(sched->credit_limit, atomic_read(&sched->credit_count), &credits)); return credits; } /** * drm_sched_can_queue -- Can we queue more to the hardware? * @sched: scheduler instance * @entity: the scheduler entity * * Return true if we can push at least one more job from @entity, false * otherwise. */ static bool drm_sched_can_queue(struct drm_gpu_scheduler *sched, struct drm_sched_entity *entity) { struct drm_sched_job *s_job; s_job = to_drm_sched_job(spsc_queue_peek(&entity->job_queue)); if (!s_job) return false; if (sched->ops->update_job_credits) { s_job->credits = sched->ops->update_job_credits(s_job); drm_WARN(sched, !s_job->credits, "Jobs with zero credits bypass job-flow control.\n"); } /* If a job exceeds the credit limit, truncate it to the credit limit * itself to guarantee forward progress. */ if (drm_WARN(sched, s_job->credits > sched->credit_limit, "Jobs may not exceed the credit limit, truncate.\n")) s_job->credits = sched->credit_limit; return drm_sched_available_credits(sched) >= s_job->credits; } static __always_inline bool drm_sched_entity_compare_before(struct rb_node *a, const struct rb_node *b) { struct drm_sched_entity *ent_a = rb_entry((a), struct drm_sched_entity, rb_tree_node); struct drm_sched_entity *ent_b = rb_entry((b), struct drm_sched_entity, rb_tree_node); return ktime_before(ent_a->oldest_job_waiting, ent_b->oldest_job_waiting); } static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity, struct drm_sched_rq *rq) { if (!RB_EMPTY_NODE(&entity->rb_tree_node)) { rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root); RB_CLEAR_NODE(&entity->rb_tree_node); } } void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity, struct drm_sched_rq *rq, ktime_t ts) { /* * Both locks need to be grabbed, one to protect from entity->rq change * for entity from within concurrent drm_sched_entity_select_rq and the * other to update the rb tree structure. */ lockdep_assert_held(&entity->lock); lockdep_assert_held(&rq->lock); drm_sched_rq_remove_fifo_locked(entity, rq); entity->oldest_job_waiting = ts; rb_add_cached(&entity->rb_tree_node, &rq->rb_tree_root, drm_sched_entity_compare_before); } /** * drm_sched_rq_init - initialize a given run queue struct * * @sched: scheduler instance to associate with this run queue * @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->rb_tree_root = RB_ROOT_CACHED; 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) { lockdep_assert_held(&entity->lock); lockdep_assert_held(&rq->lock); if (!list_empty(&entity->list)) return; atomic_inc(rq->sched->score); list_add_tail(&entity->list, &rq->entities); } /** * 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) { lockdep_assert_held(&entity->lock); if (list_empty(&entity->list)) return; spin_lock(&rq->lock); atomic_dec(rq->sched->score); list_del_init(&entity->list); if (rq->current_entity == entity) rq->current_entity = NULL; if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) drm_sched_rq_remove_fifo_locked(entity, rq); spin_unlock(&rq->lock); } /** * drm_sched_rq_select_entity_rr - Select an entity which could provide a job to run * * @sched: the gpu scheduler * @rq: scheduler run queue to check. * * Try to find the next ready entity. * * Return an entity if one is found; return an error-pointer (!NULL) if an * entity was ready, but the scheduler had insufficient credits to accommodate * its job; return NULL, if no ready entity was found. */ static struct drm_sched_entity * drm_sched_rq_select_entity_rr(struct drm_gpu_scheduler *sched, 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)) { /* If we can't queue yet, preserve the current * entity in terms of fairness. */ if (!drm_sched_can_queue(sched, entity)) { spin_unlock(&rq->lock); return ERR_PTR(-ENOSPC); } 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)) { /* If we can't queue yet, preserve the current entity in * terms of fairness. */ if (!drm_sched_can_queue(sched, entity)) { spin_unlock(&rq->lock); return ERR_PTR(-ENOSPC); } 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_rq_select_entity_fifo - Select an entity which provides a job to run * * @sched: the gpu scheduler * @rq: scheduler run queue to check. * * Find oldest waiting ready entity. * * Return an entity if one is found; return an error-pointer (!NULL) if an * entity was ready, but the scheduler had insufficient credits to accommodate * its job; return NULL, if no ready entity was found. */ static struct drm_sched_entity * drm_sched_rq_select_entity_fifo(struct drm_gpu_scheduler *sched, struct drm_sched_rq *rq) { struct rb_node *rb; spin_lock(&rq->lock); for (rb = rb_first_cached(&rq->rb_tree_root); rb; rb = rb_next(rb)) { struct drm_sched_entity *entity; entity = rb_entry(rb, struct drm_sched_entity, rb_tree_node); if (drm_sched_entity_is_ready(entity)) { /* If we can't queue yet, preserve the current entity in * terms of fairness. */ if (!drm_sched_can_queue(sched, entity)) { spin_unlock(&rq->lock); return ERR_PTR(-ENOSPC); } reinit_completion(&entity->entity_idle); break; } } spin_unlock(&rq->lock); return rb ? rb_entry(rb, struct drm_sched_entity, rb_tree_node) : NULL; } /** * drm_sched_run_job_queue - enqueue run-job work * @sched: scheduler instance */ static void drm_sched_run_job_queue(struct drm_gpu_scheduler *sched) { if (!READ_ONCE(sched->pause_submit)) queue_work(sched->submit_wq, &sched->work_run_job); } /** * __drm_sched_run_free_queue - enqueue free-job work * @sched: scheduler instance */ static void __drm_sched_run_free_queue(struct drm_gpu_scheduler *sched) { if (!READ_ONCE(sched->pause_submit)) queue_work(sched->submit_wq, &sched->work_free_job); } /** * drm_sched_run_free_queue - enqueue free-job work if ready * @sched: scheduler instance */ static void drm_sched_run_free_queue(struct drm_gpu_scheduler *sched) { struct drm_sched_job *job; spin_lock(&sched->job_list_lock); job = list_first_entry_or_null(&sched->pending_list, struct drm_sched_job, list); if (job && dma_fence_is_signaled(&job->s_fence->finished)) __drm_sched_run_free_queue(sched); spin_unlock(&sched->job_list_lock); } /** * drm_sched_job_done - complete a job * @s_job: pointer to the job which is done * * Finish the job's fence and wake up the worker thread. */ static void drm_sched_job_done(struct drm_sched_job *s_job, int result) { struct drm_sched_fence *s_fence = s_job->s_fence; struct drm_gpu_scheduler *sched = s_fence->sched; atomic_sub(s_job->credits, &sched->credit_count); atomic_dec(sched->score); trace_drm_sched_process_job(s_fence); dma_fence_get(&s_fence->finished); drm_sched_fence_finished(s_fence, result); dma_fence_put(&s_fence->finished); __drm_sched_run_free_queue(sched); } /** * drm_sched_job_done_cb - the callback for a done job * @f: fence * @cb: fence callbacks */ static void drm_sched_job_done_cb(struct dma_fence *f, struct dma_fence_cb *cb) { struct drm_sched_job *s_job = container_of(cb, struct drm_sched_job, cb); drm_sched_job_done(s_job, f->error); } /** * 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) { lockdep_assert_held(&sched->job_list_lock); if (sched->timeout != MAX_SCHEDULE_TIMEOUT && !list_empty(&sched->pending_list)) mod_delayed_work(sched->timeout_wq, &sched->work_tdr, sched->timeout); } static void drm_sched_start_timeout_unlocked(struct drm_gpu_scheduler *sched) { spin_lock(&sched->job_list_lock); drm_sched_start_timeout(sched); spin_unlock(&sched->job_list_lock); } /** * drm_sched_tdr_queue_imm: - immediately start job timeout handler * * @sched: scheduler for which the timeout handling should be started. * * Start timeout handling immediately for the named scheduler. */ void drm_sched_tdr_queue_imm(struct drm_gpu_scheduler *sched) { spin_lock(&sched->job_list_lock); sched->timeout = 0; drm_sched_start_timeout(sched); spin_unlock(&sched->job_list_lock); } EXPORT_SYMBOL(drm_sched_tdr_queue_imm); /** * 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) { if (sched->timeout_wq) mod_delayed_work(sched->timeout_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(sched->timeout_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->pending_list)) cancel_delayed_work(&sched->work_tdr); else mod_delayed_work(sched->timeout_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->list, &sched->pending_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; enum drm_gpu_sched_stat status = DRM_GPU_SCHED_STAT_NOMINAL; sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work); /* Protects against concurrent deletion in drm_sched_get_finished_job */ spin_lock(&sched->job_list_lock); job = list_first_entry_or_null(&sched->pending_list, struct drm_sched_job, list); 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->list); spin_unlock(&sched->job_list_lock); status = 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); } if (status != DRM_GPU_SCHED_STAT_ENODEV) drm_sched_start_timeout_unlocked(sched); } /** * 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 * pending list any more. * * This function is typically used for reset recovery (see the docu of * drm_sched_backend_ops.timedout_job() for details). Do not call it for * scheduler teardown, i.e., before calling drm_sched_fini(). */ void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad) { struct drm_sched_job *s_job, *tmp; drm_sched_wqueue_stop(sched); /* * Reinsert back the bad job here - now it's safe as * drm_sched_get_finished_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_finished_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->list, &sched->pending_list); /* * Iterate the job list from later to earlier one and either deactive * their HW callbacks or remove them from pending 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->pending_list, list) { if (s_job->s_fence->parent && dma_fence_remove_callback(s_job->s_fence->parent, &s_job->cb)) { dma_fence_put(s_job->s_fence->parent); s_job->s_fence->parent = NULL; atomic_sub(s_job->credits, &sched->credit_count); } else { /* * remove job from pending_list. * Locking here is for concurrent resume timeout */ spin_lock(&sched->job_list_lock); list_del_init(&s_job->list); 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_start - recover jobs after a reset * * @sched: scheduler instance * @errno: error to set on the pending fences * * This function is typically used for reset recovery (see the docu of * drm_sched_backend_ops.timedout_job() for details). Do not call it for * scheduler startup. The scheduler itself is fully operational after * drm_sched_init() succeeded. */ void drm_sched_start(struct drm_gpu_scheduler *sched, int errno) { struct drm_sched_job *s_job, *tmp; /* * 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->pending_list, list) { struct dma_fence *fence = s_job->s_fence->parent; atomic_add(s_job->credits, &sched->credit_count); if (!fence) { drm_sched_job_done(s_job, errno ?: -ECANCELED); continue; } if (dma_fence_add_callback(fence, &s_job->cb, drm_sched_job_done_cb)) drm_sched_job_done(s_job, fence->error ?: errno); } drm_sched_start_timeout_unlocked(sched); drm_sched_wqueue_start(sched); } EXPORT_SYMBOL(drm_sched_start); /** * drm_sched_resubmit_jobs - Deprecated, don't use in new code! * * @sched: scheduler instance * * Re-submitting jobs was a concept AMD came up as cheap way to implement * recovery after a job timeout. * * This turned out to be not working very well. First of all there are many * problem with the dma_fence implementation and requirements. Either the * implementation is risking deadlocks with core memory management or violating * documented implementation details of the dma_fence object. * * Drivers can still save and restore their state for recovery operations, but * we shouldn't make this a general scheduler feature around the dma_fence * interface. */ 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->pending_list, list) { 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); 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 = dma_fence_get(fence); /* Drop for orignal kref_init */ dma_fence_put(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 * @credits: the number of credits this job contributes to the schedulers * credit limit * @owner: job owner for debugging * * Refer to drm_sched_entity_push_job() documentation * for locking considerations. * * Drivers must make sure drm_sched_job_cleanup() if this function returns * successfully, even when @job is aborted before drm_sched_job_arm() is called. * * Note that this function does not assign a valid value to each struct member * of struct drm_sched_job. Take a look at that struct's documentation to see * who sets which struct member with what lifetime. * * WARNING: amdgpu abuses &drm_sched.ready to signal when the hardware * has died, which can mean that there's no valid runqueue for a @entity. * This function returns -ENOENT in this case (which probably should be -EIO as * a more meanigful return value). * * Returns 0 for success, negative error code otherwise. */ int drm_sched_job_init(struct drm_sched_job *job, struct drm_sched_entity *entity, u32 credits, void *owner) { if (!entity->rq) { /* This will most likely be followed by missing frames * or worse--a blank screen--leave a trail in the * logs, so this can be debugged easier. */ drm_err(job->sched, "%s: entity has no rq!\n", __func__); return -ENOENT; } if (unlikely(!credits)) { pr_err("*ERROR* %s: credits cannot be 0!\n", __func__); return -EINVAL; } /* * We don't know for sure how the user has allocated. Thus, zero the * struct so that unallowed (i.e., too early) usage of pointers that * this function does not set is guaranteed to lead to a NULL pointer * exception instead of UB. */ memset(job, 0, sizeof(*job)); job->entity = entity; job->credits = credits; job->s_fence = drm_sched_fence_alloc(entity, owner); if (!job->s_fence) return -ENOMEM; INIT_LIST_HEAD(&job->list); xa_init_flags(&job->dependencies, XA_FLAGS_ALLOC); return 0; } EXPORT_SYMBOL(drm_sched_job_init); /** * drm_sched_job_arm - arm a scheduler job for execution * @job: scheduler job to arm * * This arms a scheduler job for execution. Specifically it initializes the * &drm_sched_job.s_fence of @job, so that it can be attached to struct dma_resv * or other places that need to track the completion of this job. * * Refer to drm_sched_entity_push_job() documentation for locking * considerations. * * This can only be called if drm_sched_job_init() succeeded. */ void drm_sched_job_arm(struct drm_sched_job *job) { struct drm_gpu_scheduler *sched; struct drm_sched_entity *entity = job->entity; BUG_ON(!entity); drm_sched_entity_select_rq(entity); sched = entity->rq->sched; job->sched = sched; job->s_priority = entity->priority; job->id = atomic64_inc_return(&sched->job_id_count); drm_sched_fence_init(job->s_fence, job->entity); } EXPORT_SYMBOL(drm_sched_job_arm); /** * drm_sched_job_add_dependency - adds the fence as a job dependency * @job: scheduler job to add the dependencies to * @fence: the dma_fence to add to the list of dependencies. * * Note that @fence is consumed in both the success and error cases. * * Returns: * 0 on success, or an error on failing to expand the array. */ int drm_sched_job_add_dependency(struct drm_sched_job *job, struct dma_fence *fence) { struct dma_fence *entry; unsigned long index; u32 id = 0; int ret; if (!fence) return 0; /* Deduplicate if we already depend on a fence from the same context. * This lets the size of the array of deps scale with the number of * engines involved, rather than the number of BOs. */ xa_for_each(&job->dependencies, index, entry) { if (entry->context != fence->context) continue; if (dma_fence_is_later(fence, entry)) { dma_fence_put(entry); xa_store(&job->dependencies, index, fence, GFP_KERNEL); } else { dma_fence_put(fence); } return 0; } ret = xa_alloc(&job->dependencies, &id, fence, xa_limit_32b, GFP_KERNEL); if (ret != 0) dma_fence_put(fence); return ret; } EXPORT_SYMBOL(drm_sched_job_add_dependency); /** * drm_sched_job_add_syncobj_dependency - adds a syncobj's fence as a job dependency * @job: scheduler job to add the dependencies to * @file: drm file private pointer * @handle: syncobj handle to lookup * @point: timeline point * * This adds the fence matching the given syncobj to @job. * * Returns: * 0 on success, or an error on failing to expand the array. */ int drm_sched_job_add_syncobj_dependency(struct drm_sched_job *job, struct drm_file *file, u32 handle, u32 point) { struct dma_fence *fence; int ret; ret = drm_syncobj_find_fence(file, handle, point, 0, &fence); if (ret) return ret; return drm_sched_job_add_dependency(job, fence); } EXPORT_SYMBOL(drm_sched_job_add_syncobj_dependency); /** * drm_sched_job_add_resv_dependencies - add all fences from the resv to the job * @job: scheduler job to add the dependencies to * @resv: the dma_resv object to get the fences from * @usage: the dma_resv_usage to use to filter the fences * * This adds all fences matching the given usage from @resv to @job. * Must be called with the @resv lock held. * * Returns: * 0 on success, or an error on failing to expand the array. */ int drm_sched_job_add_resv_dependencies(struct drm_sched_job *job, struct dma_resv *resv, enum dma_resv_usage usage) { struct dma_resv_iter cursor; struct dma_fence *fence; int ret; dma_resv_assert_held(resv); dma_resv_for_each_fence(&cursor, resv, usage, fence) { /* Make sure to grab an additional ref on the added fence */ dma_fence_get(fence); ret = drm_sched_job_add_dependency(job, fence); if (ret) { dma_fence_put(fence); return ret; } } return 0; } EXPORT_SYMBOL(drm_sched_job_add_resv_dependencies); /** * drm_sched_job_add_implicit_dependencies - adds implicit dependencies as job * dependencies * @job: scheduler job to add the dependencies to * @obj: the gem object to add new dependencies from. * @write: whether the job might write the object (so we need to depend on * shared fences in the reservation object). * * This should be called after drm_gem_lock_reservations() on your array of * GEM objects used in the job but before updating the reservations with your * own fences. * * Returns: * 0 on success, or an error on failing to expand the array. */ int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job, struct drm_gem_object *obj, bool write) { return drm_sched_job_add_resv_dependencies(job, obj->resv, dma_resv_usage_rw(write)); } EXPORT_SYMBOL(drm_sched_job_add_implicit_dependencies); /** * drm_sched_job_cleanup - clean up scheduler job resources * @job: scheduler job to clean up * * Cleans up the resources allocated with drm_sched_job_init(). * * Drivers should call this from their error unwind code if @job is aborted * before drm_sched_job_arm() is called. * * After that point of no return @job is committed to be executed by the * scheduler, and this function should be called from the * &drm_sched_backend_ops.free_job callback. */ void drm_sched_job_cleanup(struct drm_sched_job *job) { struct dma_fence *fence; unsigned long index; if (kref_read(&job->s_fence->finished.refcount)) { /* drm_sched_job_arm() has been called */ dma_fence_put(&job->s_fence->finished); } else { /* aborted job before committing to run it */ drm_sched_fence_free(job->s_fence); } job->s_fence = NULL; xa_for_each(&job->dependencies, index, fence) { dma_fence_put(fence); } xa_destroy(&job->dependencies); } EXPORT_SYMBOL(drm_sched_job_cleanup); /** * drm_sched_wakeup - Wake up the scheduler if it is ready to queue * @sched: scheduler instance * * Wake up the scheduler if we can queue jobs. */ void drm_sched_wakeup(struct drm_gpu_scheduler *sched) { drm_sched_run_job_queue(sched); } /** * drm_sched_select_entity - Select next entity to process * * @sched: scheduler instance * * Return an entity to process or NULL if none are found. * * Note, that we break out of the for-loop when "entity" is non-null, which can * also be an error-pointer--this assures we don't process lower priority * run-queues. See comments in the respectively called functions. */ static struct drm_sched_entity * drm_sched_select_entity(struct drm_gpu_scheduler *sched) { struct drm_sched_entity *entity; int i; /* Start with the highest priority. */ for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) { entity = drm_sched_policy == DRM_SCHED_POLICY_FIFO ? drm_sched_rq_select_entity_fifo(sched, sched->sched_rq[i]) : drm_sched_rq_select_entity_rr(sched, sched->sched_rq[i]); if (entity) break; } return IS_ERR(entity) ? NULL : entity; } /** * drm_sched_get_finished_job - fetch the next finished job to be destroyed * * @sched: scheduler instance * * Returns the next finished job from the pending list (if there is one) * ready for it to be destroyed. */ static struct drm_sched_job * drm_sched_get_finished_job(struct drm_gpu_scheduler *sched) { struct drm_sched_job *job, *next; spin_lock(&sched->job_list_lock); job = list_first_entry_or_null(&sched->pending_list, struct drm_sched_job, list); if (job && dma_fence_is_signaled(&job->s_fence->finished)) { /* remove job from pending_list */ list_del_init(&job->list); /* cancel this job's TO timer */ cancel_delayed_work(&sched->work_tdr); /* make the scheduled timestamp more accurate */ next = list_first_entry_or_null(&sched->pending_list, typeof(*next), list); if (next) { if (test_bit(DMA_FENCE_FLAG_TIMESTAMP_BIT, &next->s_fence->scheduled.flags)) next->s_fence->scheduled.timestamp = dma_fence_timestamp(&job->s_fence->finished); /* start TO timer for next job */ drm_sched_start_timeout(sched); } } else { job = NULL; } 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_score = UINT_MAX, num_score; 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_score = atomic_read(sched->score); if (num_score < min_score) { min_score = num_score; picked_sched = sched; } } return picked_sched; } EXPORT_SYMBOL(drm_sched_pick_best); /** * drm_sched_free_job_work - worker to call free_job * * @w: free job work */ static void drm_sched_free_job_work(struct work_struct *w) { struct drm_gpu_scheduler *sched = container_of(w, struct drm_gpu_scheduler, work_free_job); struct drm_sched_job *job; if (READ_ONCE(sched->pause_submit)) return; job = drm_sched_get_finished_job(sched); if (job) sched->ops->free_job(job); drm_sched_run_free_queue(sched); drm_sched_run_job_queue(sched); } /** * drm_sched_run_job_work - worker to call run_job * * @w: run job work */ static void drm_sched_run_job_work(struct work_struct *w) { struct drm_gpu_scheduler *sched = container_of(w, struct drm_gpu_scheduler, work_run_job); struct drm_sched_entity *entity; struct dma_fence *fence; struct drm_sched_fence *s_fence; struct drm_sched_job *sched_job; int r; if (READ_ONCE(sched->pause_submit)) return; /* Find entity with a ready job */ entity = drm_sched_select_entity(sched); if (!entity) return; /* No more work */ sched_job = drm_sched_entity_pop_job(entity); if (!sched_job) { complete_all(&entity->entity_idle); drm_sched_run_job_queue(sched); return; } s_fence = sched_job->s_fence; atomic_add(sched_job->credits, &sched->credit_count); drm_sched_job_begin(sched_job); trace_drm_run_job(sched_job, entity); fence = sched->ops->run_job(sched_job); complete_all(&entity->entity_idle); drm_sched_fence_scheduled(s_fence, fence); if (!IS_ERR_OR_NULL(fence)) { /* Drop for original kref_init of the fence */ dma_fence_put(fence); r = dma_fence_add_callback(fence, &sched_job->cb, drm_sched_job_done_cb); if (r == -ENOENT) drm_sched_job_done(sched_job, fence->error); else if (r) DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n", r); } else { drm_sched_job_done(sched_job, IS_ERR(fence) ? PTR_ERR(fence) : 0); } wake_up(&sched->job_scheduled); drm_sched_run_job_queue(sched); } /** * drm_sched_init - Init a gpu scheduler instance * * @sched: scheduler instance * @ops: backend operations for this scheduler * @submit_wq: workqueue to use for submission. If NULL, an ordered wq is * allocated and used * @num_rqs: number of runqueues, one for each priority, up to DRM_SCHED_PRIORITY_COUNT * @credit_limit: the number of credits this scheduler can hold from all jobs * @hang_limit: number of times to allow a job to hang before dropping it * @timeout: timeout value in jiffies for the scheduler * @timeout_wq: workqueue to use for timeout work. If NULL, the system_wq is * used * @score: optional score atomic shared with other schedulers * @name: name used for debugging * @dev: target &struct device * * Return 0 on success, otherwise error code. */ int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_backend_ops *ops, struct workqueue_struct *submit_wq, u32 num_rqs, u32 credit_limit, unsigned int hang_limit, long timeout, struct workqueue_struct *timeout_wq, atomic_t *score, const char *name, struct device *dev) { int i; sched->ops = ops; sched->credit_limit = credit_limit; sched->name = name; sched->timeout = timeout; sched->timeout_wq = timeout_wq ? : system_wq; sched->hang_limit = hang_limit; sched->score = score ? score : &sched->_score; sched->dev = dev; if (num_rqs > DRM_SCHED_PRIORITY_COUNT) { /* This is a gross violation--tell drivers what the problem is. */ drm_err(sched, "%s: num_rqs cannot be greater than DRM_SCHED_PRIORITY_COUNT\n", __func__); return -EINVAL; } else if (sched->sched_rq) { /* Not an error, but warn anyway so drivers can * fine-tune their DRM calling order, and return all * is good. */ drm_warn(sched, "%s: scheduler already initialized!\n", __func__); return 0; } if (submit_wq) { sched->submit_wq = submit_wq; sched->own_submit_wq = false; } else { #ifdef CONFIG_LOCKDEP sched->submit_wq = alloc_ordered_workqueue_lockdep_map(name, WQ_MEM_RECLAIM, &drm_sched_lockdep_map); #else sched->submit_wq = alloc_ordered_workqueue(name, WQ_MEM_RECLAIM); #endif if (!sched->submit_wq) return -ENOMEM; sched->own_submit_wq = true; } sched->sched_rq = kmalloc_array(num_rqs, sizeof(*sched->sched_rq), GFP_KERNEL | __GFP_ZERO); if (!sched->sched_rq) goto Out_check_own; sched->num_rqs = num_rqs; for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) { sched->sched_rq[i] = kzalloc(sizeof(*sched->sched_rq[i]), GFP_KERNEL); if (!sched->sched_rq[i]) goto Out_unroll; drm_sched_rq_init(sched, sched->sched_rq[i]); } init_waitqueue_head(&sched->job_scheduled); INIT_LIST_HEAD(&sched->pending_list); spin_lock_init(&sched->job_list_lock); atomic_set(&sched->credit_count, 0); INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout); INIT_WORK(&sched->work_run_job, drm_sched_run_job_work); INIT_WORK(&sched->work_free_job, drm_sched_free_job_work); atomic_set(&sched->_score, 0); atomic64_set(&sched->job_id_count, 0); sched->pause_submit = false; sched->ready = true; return 0; Out_unroll: for (--i ; i >= DRM_SCHED_PRIORITY_KERNEL; i--) kfree(sched->sched_rq[i]); kfree(sched->sched_rq); sched->sched_rq = NULL; Out_check_own: if (sched->own_submit_wq) destroy_workqueue(sched->submit_wq); drm_err(sched, "%s: Failed to setup GPU scheduler--out of memory\n", __func__); return -ENOMEM; } EXPORT_SYMBOL(drm_sched_init); /** * drm_sched_fini - Destroy a gpu scheduler * * @sched: scheduler instance * * Tears down and cleans up the scheduler. * * This stops submission of new jobs to the hardware through * drm_sched_backend_ops.run_job(). Consequently, drm_sched_backend_ops.free_job() * will not be called for all jobs still in drm_gpu_scheduler.pending_list. * There is no solution for this currently. Thus, it is up to the driver to make * sure that * a) drm_sched_fini() is only called after for all submitted jobs * drm_sched_backend_ops.free_job() has been called or that * b) the jobs for which drm_sched_backend_ops.free_job() has not been called * after drm_sched_fini() ran are freed manually. * * FIXME: Take care of the above problem and prevent this function from leaking * the jobs in drm_gpu_scheduler.pending_list under any circumstances. */ void drm_sched_fini(struct drm_gpu_scheduler *sched) { struct drm_sched_entity *s_entity; int i; drm_sched_wqueue_stop(sched); for (i = DRM_SCHED_PRIORITY_KERNEL; i < sched->num_rqs; i++) { struct drm_sched_rq *rq = sched->sched_rq[i]; spin_lock(&rq->lock); list_for_each_entry(s_entity, &rq->entities, list) /* * Prevents reinsertion and marks job_queue as idle, * it will be removed from the rq in drm_sched_entity_fini() * eventually */ s_entity->stopped = true; spin_unlock(&rq->lock); kfree(sched->sched_rq[i]); } /* Wakeup everyone stuck in drm_sched_entity_flush for this scheduler */ wake_up_all(&sched->job_scheduled); /* Confirm no work left behind accessing device structures */ cancel_delayed_work_sync(&sched->work_tdr); if (sched->own_submit_wq) destroy_workqueue(sched->submit_wq); sched->ready = false; kfree(sched->sched_rq); sched->sched_rq = NULL; } EXPORT_SYMBOL(drm_sched_fini); /** * 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 change @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_HIGH; i < sched->num_rqs; 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 (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_wqueue_ready - Is the scheduler ready for submission * * @sched: scheduler instance * * Returns true if submission is ready */ bool drm_sched_wqueue_ready(struct drm_gpu_scheduler *sched) { return sched->ready; } EXPORT_SYMBOL(drm_sched_wqueue_ready); /** * drm_sched_wqueue_stop - stop scheduler submission * @sched: scheduler instance * * Stops the scheduler from pulling new jobs from entities. It also stops * freeing jobs automatically through drm_sched_backend_ops.free_job(). */ void drm_sched_wqueue_stop(struct drm_gpu_scheduler *sched) { WRITE_ONCE(sched->pause_submit, true); cancel_work_sync(&sched->work_run_job); cancel_work_sync(&sched->work_free_job); } EXPORT_SYMBOL(drm_sched_wqueue_stop); /** * drm_sched_wqueue_start - start scheduler submission * @sched: scheduler instance * * Restarts the scheduler after drm_sched_wqueue_stop() has stopped it. * * This function is not necessary for 'conventional' startup. The scheduler is * fully operational after drm_sched_init() succeeded. */ void drm_sched_wqueue_start(struct drm_gpu_scheduler *sched) { WRITE_ONCE(sched->pause_submit, false); queue_work(sched->submit_wq, &sched->work_run_job); queue_work(sched->submit_wq, &sched->work_free_job); } EXPORT_SYMBOL(drm_sched_wqueue_start);