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|
/*
* 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 <linux/kthread.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/completion.h>
#include <linux/dma-resv.h>
#include <uapi/linux/sched/types.h>
#include <drm/drm_print.h>
#include <drm/drm_gem.h>
#include <drm/drm_syncobj.h>
#include <drm/gpu_scheduler.h>
#include <drm/spsc_queue.h>
#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)
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 __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 inline void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity)
{
struct drm_sched_rq *rq = entity->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(struct drm_sched_entity *entity, 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.
*/
spin_lock(&entity->rq_lock);
spin_lock(&entity->rq->lock);
drm_sched_rq_remove_fifo_locked(entity);
entity->oldest_job_waiting = ts;
rb_add_cached(&entity->rb_tree_node, &entity->rq->rb_tree_root,
drm_sched_entity_compare_before);
spin_unlock(&entity->rq->lock);
spin_unlock(&entity->rq_lock);
}
/**
* 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)
{
if (!list_empty(&entity->list))
return;
spin_lock(&rq->lock);
atomic_inc(rq->sched->score);
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);
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);
spin_unlock(&rq->lock);
}
/**
* drm_sched_rq_select_entity_rr - 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_rr(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_rq_select_entity_fifo - Select an entity which provides a job to run
*
* @rq: scheduler run queue to check.
*
* Find oldest waiting ready entity, returns NULL if none found.
*/
static struct drm_sched_entity *
drm_sched_rq_select_entity_fifo(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)) {
rq->current_entity = entity;
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_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)
{
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->score);
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_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);
}
/**
* 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->pending_list))
queue_delayed_work(sched->timeout_wq, &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(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_cleanup_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) {
spin_lock(&sched->job_list_lock);
drm_sched_start_timeout(sched);
spin_unlock(&sched->job_list_lock);
}
}
/**
* 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.
*
*/
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->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_dec(&sched->hw_rq_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
* @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->pending_list, list) {
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_job_done_cb);
if (r == -ENOENT)
drm_sched_job_done(s_job);
else if (r)
DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
r);
} else
drm_sched_job_done(s_job);
}
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 - 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
* @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.
*
* 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,
void *owner)
{
if (!entity->rq)
return -ENOENT;
job->entity = entity;
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->rq - sched->sched_rq;
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_private: 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_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_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
entity = drm_sched_policy == DRM_SCHED_POLICY_FIFO ?
drm_sched_rq_select_entity_fifo(&sched->sched_rq[i]) :
drm_sched_rq_select_entity_rr(&sched->sched_rq[i]);
if (entity)
break;
}
return entity;
}
/**
* drm_sched_get_cleanup_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_cleanup_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) {
next->s_fence->scheduled.timestamp =
job->s_fence->finished.timestamp;
/* start TO timer for next job */
drm_sched_start_timeout(sched);
}
} else {
job = NULL;
}
spin_unlock(&sched->job_list_lock);
if (job) {
job->entity->elapsed_ns += ktime_to_ns(
ktime_sub(job->s_fence->finished.timestamp,
job->s_fence->scheduled.timestamp));
}
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_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 drm_gpu_scheduler *sched = (struct drm_gpu_scheduler *)param;
int r;
sched_set_fifo_low(current);
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);
if (!entity)
continue;
sched_job = drm_sched_entity_pop_job(entity);
if (!sched_job) {
complete_all(&entity->entity_idle);
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);
complete_all(&entity->entity_idle);
drm_sched_fence_scheduled(s_fence);
if (!IS_ERR_OR_NULL(fence)) {
s_fence->parent = dma_fence_get(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);
else if (r)
DRM_DEV_ERROR(sched->dev, "fence add callback failed (%d)\n",
r);
} else {
if (IS_ERR(fence))
dma_fence_set_error(&s_fence->finished, PTR_ERR(fence));
drm_sched_job_done(sched_job);
}
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
* @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,
unsigned hw_submission, unsigned hang_limit,
long timeout, struct workqueue_struct *timeout_wq,
atomic_t *score, const char *name, struct device *dev)
{
int i, ret;
sched->ops = ops;
sched->hw_submission_limit = hw_submission;
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;
for (i = DRM_SCHED_PRIORITY_MIN; i < DRM_SCHED_PRIORITY_COUNT; 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->pending_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->_score, 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_DEV_ERROR(sched->dev, "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)
{
struct drm_sched_entity *s_entity;
int i;
if (sched->thread)
kthread_stop(sched->thread);
for (i = DRM_SCHED_PRIORITY_COUNT - 1; i >= DRM_SCHED_PRIORITY_MIN; i--) {
struct drm_sched_rq *rq = &sched->sched_rq[i];
if (!rq)
continue;
spin_lock(&rq->lock);
list_for_each_entry(s_entity, &rq->entities, list)
/*
* Prevents reinsertion and marks job_queue as idle,
* it will removed from rq in drm_sched_entity_fini
* eventually
*/
s_entity->stopped = true;
spin_unlock(&rq->lock);
}
/* 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);
sched->ready = false;
}
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_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 (entity->guilty)
atomic_set(entity->guilty, 1);
break;
}
}
spin_unlock(&rq->lock);
if (&entity->list != &rq->entities)
break;
}
}
}
EXPORT_SYMBOL(drm_sched_increase_karma);
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