/*
* 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 <uapi/linux/sched/types.h>
#include <drm/drmP.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)
static bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
static void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
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.
*/
static 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.
*/
static 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;
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;
spin_unlock(&rq->lock);
return entity;
}
if (entity == rq->current_entity)
break;
}
spin_unlock(&rq->lock);
return NULL;
}
/**
* drm_sched_entity_init - Init a context entity used by scheduler when
* submit to HW ring.
*
* @entity: scheduler entity to init
* @rq_list: the list of run queue on which jobs from this
* entity can be submitted
* @num_rq_list: number of run queue in rq_list
* @guilty: atomic_t set to 1 when a job on this queue
* is found to be guilty causing a timeout
*
* Note: the rq_list should have atleast one element to schedule
* the entity
*
* Returns 0 on success or a negative error code on failure.
*/
int drm_sched_entity_init(struct drm_sched_entity *entity,
struct drm_sched_rq **rq_list,
unsigned int num_rq_list,
atomic_t *guilty)
{
int i;
if (!(entity && rq_list && num_rq_list > 0 && rq_list[0]))
return -EINVAL;
memset(entity, 0, sizeof(struct drm_sched_entity));
INIT_LIST_HEAD(&entity->list);
entity->rq = rq_list[0];
entity->guilty = guilty;
entity->num_rq_list = num_rq_list;
entity->rq_list = kcalloc(num_rq_list, sizeof(struct drm_sched_rq *),
GFP_KERNEL);
for (i = 0; i < num_rq_list; ++i)
entity->rq_list[i] = rq_list[i];
entity->last_scheduled = NULL;
spin_lock_init(&entity->rq_lock);
spsc_queue_init(&entity->job_queue);
atomic_set(&entity->fence_seq, 0);
entity->fence_context = dma_fence_context_alloc(2);
return 0;
}
EXPORT_SYMBOL(drm_sched_entity_init);
/**
* drm_sched_entity_is_idle - Check if entity is idle
*
* @entity: scheduler entity
*
* Returns true if the entity does not have any unscheduled jobs.
*/
static bool drm_sched_entity_is_idle(struct drm_sched_entity *entity)
{
rmb();
if (list_empty(&entity->list) ||
spsc_queue_peek(&entity->job_queue) == NULL)
return true;
return false;
}
/**
* drm_sched_entity_is_ready - Check if entity is ready
*
* @entity: scheduler entity
*
* Return true if entity could provide a job.
*/
static bool drm_sched_entity_is_ready(struct drm_sched_entity *entity)
{
if (spsc_queue_peek(&entity->job_queue) == NULL)
return false;
if (READ_ONCE(entity->dependency))
return false;
return true;
}
/**
* drm_sched_entity_get_free_sched - Get the rq from rq_list with least load
*
* @entity: scheduler entity
*
* Return the pointer to the rq with least load.
*/
static struct drm_sched_rq *
drm_sched_entity_get_free_sched(struct drm_sched_entity *entity)
{
struct drm_sched_rq *rq = NULL;
unsigned int min_jobs = UINT_MAX, num_jobs;
int i;
for (i = 0; i < entity->num_rq_list; ++i) {
num_jobs = atomic_read(&entity->rq_list[i]->sched->num_jobs);
if (num_jobs < min_jobs) {
min_jobs = num_jobs;
rq = entity->rq_list[i];
}
}
return rq;
}
static void drm_sched_entity_kill_jobs_cb(struct dma_fence *f,
struct dma_fence_cb *cb)
{
struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
finish_cb);
drm_sched_fence_finished(job->s_fence);
WARN_ON(job->s_fence->parent);
dma_fence_put(&job->s_fence->finished);
job->sched->ops->free_job(job);
}
/**
* drm_sched_entity_flush - Flush a context entity
*
* @entity: scheduler entity
* @timeout: time to wait in for Q to become empty in jiffies.
*
* Splitting drm_sched_entity_fini() into two functions, The first one does the waiting,
* removes the entity from the runqueue and returns an error when the process was killed.
*
* Returns the remaining time in jiffies left from the input timeout
*/
long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout)
{
struct drm_gpu_scheduler *sched;
struct task_struct *last_user;
long ret = timeout;
sched = entity->rq->sched;
/**
* The client will not queue more IBs during this fini, consume existing
* queued IBs or discard them on SIGKILL
*/
if (current->flags & PF_EXITING) {
if (timeout)
ret = wait_event_timeout(
sched->job_scheduled,
drm_sched_entity_is_idle(entity),
timeout);
} else
wait_event_killable(sched->job_scheduled, drm_sched_entity_is_idle(entity));
/* For killed process disable any more IBs enqueue right now */
last_user = cmpxchg(&entity->last_user, current->group_leader, NULL);
if ((!last_user || last_user == current->group_leader) &&
(current->flags & PF_EXITING) && (current->exit_code == SIGKILL))
drm_sched_rq_remove_entity(entity->rq, entity);
return ret;
}
EXPORT_SYMBOL(drm_sched_entity_flush);
/**
* drm_sched_entity_cleanup - Destroy a context entity
*
* @entity: scheduler entity
*
* This should be called after @drm_sched_entity_do_release. It goes over the
* entity and signals all jobs with an error code if the process was killed.
*
*/
void drm_sched_entity_fini(struct drm_sched_entity *entity)
{
struct drm_gpu_scheduler *sched;
sched = entity->rq->sched;
drm_sched_rq_remove_entity(entity->rq, entity);
/* Consumption of existing IBs wasn't completed. Forcefully
* remove them here.
*/
if (spsc_queue_peek(&entity->job_queue)) {
struct drm_sched_job *job;
int r;
/* Park the kernel for a moment to make sure it isn't processing
* our enity.
*/
kthread_park(sched->thread);
kthread_unpark(sched->thread);
if (entity->dependency) {
dma_fence_remove_callback(entity->dependency,
&entity->cb);
dma_fence_put(entity->dependency);
entity->dependency = NULL;
}
while ((job = to_drm_sched_job(spsc_queue_pop(&entity->job_queue)))) {
struct drm_sched_fence *s_fence = job->s_fence;
drm_sched_fence_scheduled(s_fence);
dma_fence_set_error(&s_fence->finished, -ESRCH);
/*
* When pipe is hanged by older entity, new entity might
* not even have chance to submit it's first job to HW
* and so entity->last_scheduled will remain NULL
*/
if (!entity->last_scheduled) {
drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
} else {
r = dma_fence_add_callback(entity->last_scheduled, &job->finish_cb,
drm_sched_entity_kill_jobs_cb);
if (r == -ENOENT)
drm_sched_entity_kill_jobs_cb(NULL, &job->finish_cb);
else if (r)
DRM_ERROR("fence add callback failed (%d)\n", r);
}
}
}
dma_fence_put(entity->last_scheduled);
entity->last_scheduled = NULL;
kfree(entity->rq_list);
}
EXPORT_SYMBOL(drm_sched_entity_fini);
/**
* drm_sched_entity_fini - Destroy a context entity
*
* @entity: scheduler entity
*
* Calls drm_sched_entity_do_release() and drm_sched_entity_cleanup()
*/
void drm_sched_entity_destroy(struct drm_sched_entity *entity)
{
drm_sched_entity_flush(entity, MAX_WAIT_SCHED_ENTITY_Q_EMPTY);
drm_sched_entity_fini(entity);
}
EXPORT_SYMBOL(drm_sched_entity_destroy);
static void drm_sched_entity_wakeup(struct dma_fence *f, struct dma_fence_cb *cb)
{
struct drm_sched_entity *entity =
container_of(cb, struct drm_sched_entity, cb);
entity->dependency = NULL;
dma_fence_put(f);
drm_sched_wakeup(entity->rq->sched);
}
static void drm_sched_entity_clear_dep(struct dma_fence *f, struct dma_fence_cb *cb)
{
struct drm_sched_entity *entity =
container_of(cb, struct drm_sched_entity, cb);
entity->dependency = NULL;
dma_fence_put(f);
}
/**
* drm_sched_entity_set_rq_priority - helper for drm_sched_entity_set_priority
*/
static void drm_sched_entity_set_rq_priority(struct drm_sched_rq **rq,
enum drm_sched_priority priority)
{
*rq = &(*rq)->sched->sched_rq[priority];
}
/**
* drm_sched_entity_set_priority - Sets priority of the entity
*
* @entity: scheduler entity
* @priority: scheduler priority
*
* Update the priority of runqueus used for the entity.
*/
void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
enum drm_sched_priority priority)
{
unsigned int i;
spin_lock(&entity->rq_lock);
for (i = 0; i < entity->num_rq_list; ++i)
drm_sched_entity_set_rq_priority(&entity->rq_list[i], priority);
drm_sched_rq_remove_entity(entity->rq, entity);
drm_sched_entity_set_rq_priority(&entity->rq, priority);
drm_sched_rq_add_entity(entity->rq, entity);
spin_unlock(&entity->rq_lock);
}
EXPORT_SYMBOL(drm_sched_entity_set_priority);
/**
* 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);
static bool drm_sched_entity_add_dependency_cb(struct drm_sched_entity *entity)
{
struct drm_gpu_scheduler *sched = entity->rq->sched;
struct dma_fence * fence = entity->dependency;
struct drm_sched_fence *s_fence;
if (fence->context == entity->fence_context ||
fence->context == entity->fence_context + 1) {
/*
* Fence is a scheduled/finished fence from a job
* which belongs to the same entity, we can ignore
* fences from ourself
*/
dma_fence_put(entity->dependency);
return false;
}
s_fence = to_drm_sched_fence(fence);
if (s_fence && s_fence->sched == sched) {
/*
* Fence is from the same scheduler, only need to wait for
* it to be scheduled
*/
fence = dma_fence_get(&s_fence->scheduled);
dma_fence_put(entity->dependency);
entity->dependency = fence;
if (!dma_fence_add_callback(fence, &entity->cb,
drm_sched_entity_clear_dep))
return true;
/* Ignore it when it is already scheduled */
dma_fence_put(fence);
return false;
}
if (!dma_fence_add_callback(entity->dependency, &entity->cb,
drm_sched_entity_wakeup))
return true;
dma_fence_put(entity->dependency);
return false;
}
static struct drm_sched_job *
drm_sched_entity_pop_job(struct drm_sched_entity *entity)
{
struct drm_gpu_scheduler *sched = entity->rq->sched;
struct drm_sched_job *sched_job = to_drm_sched_job(
spsc_queue_peek(&entity->job_queue));
if (!sched_job)
return NULL;
sched_job->sched = sched;
sched_job->s_fence->sched = sched;
while ((entity->dependency = sched->ops->dependency(sched_job, entity))) {
if (drm_sched_entity_add_dependency_cb(entity)) {
trace_drm_sched_job_wait_dep(sched_job, entity->dependency);
return NULL;
}
}
/* skip jobs from entity that marked guilty */
if (entity->guilty && atomic_read(entity->guilty))
dma_fence_set_error(&sched_job->s_fence->finished, -ECANCELED);
dma_fence_put(entity->last_scheduled);
entity->last_scheduled = dma_fence_get(&sched_job->s_fence->finished);
spsc_queue_pop(&entity->job_queue);
return sched_job;
}
/**
* drm_sched_entity_push_job - Submit a job to the entity's job queue
*
* @sched_job: job to submit
* @entity: scheduler entity
*
* Note: To guarantee that the order of insertion to queue matches
* the job's fence sequence number this function should be
* called with drm_sched_job_init under common lock.
*
* Returns 0 for success, negative error code otherwise.
*/
void drm_sched_entity_push_job(struct drm_sched_job *sched_job,
struct drm_sched_entity *entity)
{
struct drm_sched_rq *rq = entity->rq;
bool first, reschedule, idle;
idle = entity->last_scheduled == NULL ||
dma_fence_is_signaled(entity->last_scheduled);
first = spsc_queue_count(&entity->job_queue) == 0;
reschedule = idle && first && (entity->num_rq_list > 1);
if (reschedule) {
rq = drm_sched_entity_get_free_sched(entity);
spin_lock(&entity->rq_lock);
drm_sched_rq_remove_entity(entity->rq, entity);
entity->rq = rq;
spin_unlock(&entity->rq_lock);
}
trace_drm_sched_job(sched_job, entity);
atomic_inc(&entity->rq->sched->num_jobs);
WRITE_ONCE(entity->last_user, current->group_leader);
first = spsc_queue_push(&entity->job_queue, &sched_job->queue_node);
/* first job wakes up scheduler */
if (first) {
/* Add the entity to the run queue */
spin_lock(&entity->rq_lock);
if (!entity->rq) {
DRM_ERROR("Trying to push to a killed entity\n");
spin_unlock(&entity->rq_lock);
return;
}
drm_sched_rq_add_entity(entity->rq, entity);
spin_unlock(&entity->rq_lock);
drm_sched_wakeup(entity->rq->sched);
}
}
EXPORT_SYMBOL(drm_sched_entity_push_job);
/* job_finish is called after hw fence signaled
*/
static void drm_sched_job_finish(struct work_struct *work)
{
struct drm_sched_job *s_job = container_of(work, struct drm_sched_job,
finish_work);
struct drm_gpu_scheduler *sched = s_job->sched;
/*
* Canceling the timeout without removing our job from the ring mirror
* list is safe, as we will only end up in this worker if our jobs
* finished fence has been signaled. So even if some another worker
* manages to find this job as the next job in the list, the fence
* signaled check below will prevent the timeout to be restarted.
*/
cancel_delayed_work_sync(&s_job->work_tdr);
spin_lock(&sched->job_list_lock);
/* queue TDR for next job */
if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
!list_is_last(&s_job->node, &sched->ring_mirror_list)) {
struct drm_sched_job *next = list_next_entry(s_job, node);
if (!dma_fence_is_signaled(&next->s_fence->finished))
schedule_delayed_work(&next->work_tdr, sched->timeout);
}
/* remove job from ring_mirror_list */
list_del(&s_job->node);
spin_unlock(&sched->job_list_lock);
dma_fence_put(&s_job->s_fence->finished);
sched->ops->free_job(s_job);
}
static void drm_sched_job_finish_cb(struct dma_fence *f,
struct dma_fence_cb *cb)
{
struct drm_sched_job *job = container_of(cb, struct drm_sched_job,
finish_cb);
schedule_work(&job->finish_work);
}
static void drm_sched_job_begin(struct drm_sched_job *s_job)
{
struct drm_gpu_scheduler *sched = s_job->sched;
dma_fence_add_callback(&s_job->s_fence->finished, &s_job->finish_cb,
drm_sched_job_finish_cb);
spin_lock(&sched->job_list_lock);
list_add_tail(&s_job->node, &sched->ring_mirror_list);
if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
list_first_entry_or_null(&sched->ring_mirror_list,
struct drm_sched_job, node) == s_job)
schedule_delayed_work(&s_job->work_tdr, sched->timeout);
spin_unlock(&sched->job_list_lock);
}
static void drm_sched_job_timedout(struct work_struct *work)
{
struct drm_sched_job *job = container_of(work, struct drm_sched_job,
work_tdr.work);
job->sched->ops->timedout_job(job);
}
/**
* drm_sched_hw_job_reset - stop the scheduler if it contains the bad job
*
* @sched: scheduler instance
* @bad: bad scheduler job
*
*/
void drm_sched_hw_job_reset(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad)
{
struct drm_sched_job *s_job;
struct drm_sched_entity *entity, *tmp;
int i;
spin_lock(&sched->job_list_lock);
list_for_each_entry_reverse(s_job, &sched->ring_mirror_list, node) {
if (s_job->s_fence->parent &&
dma_fence_remove_callback(s_job->s_fence->parent,
&s_job->s_fence->cb)) {
dma_fence_put(s_job->s_fence->parent);
s_job->s_fence->parent = NULL;
atomic_dec(&sched->hw_rq_count);
}
}
spin_unlock(&sched->job_list_lock);
if (bad && bad->s_priority != DRM_SCHED_PRIORITY_KERNEL) {
atomic_inc(&bad->karma);
/* don't increase @bad's karma if it's from KERNEL RQ,
* becuase sometimes GPU hang would cause kernel jobs (like VM updating jobs)
* corrupt but keep in mind that kernel jobs always considered good.
*/
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_hw_job_reset);
/**
* drm_sched_job_recovery - recover jobs after a reset
*
* @sched: scheduler instance
*
*/
void drm_sched_job_recovery(struct drm_gpu_scheduler *sched)
{
struct drm_sched_job *s_job, *tmp;
bool found_guilty = false;
int r;
spin_lock(&sched->job_list_lock);
s_job = list_first_entry_or_null(&sched->ring_mirror_list,
struct drm_sched_job, node);
if (s_job && sched->timeout != MAX_SCHEDULE_TIMEOUT)
schedule_delayed_work(&s_job->work_tdr, sched->timeout);
list_for_each_entry_safe(s_job, tmp, &sched->ring_mirror_list, node) {
struct drm_sched_fence *s_fence = s_job->s_fence;
struct dma_fence *fence;
uint64_t guilty_context;
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);
spin_unlock(&sched->job_list_lock);
fence = sched->ops->run_job(s_job);
atomic_inc(&sched->hw_rq_count);
if (fence) {
s_fence->parent = dma_fence_get(fence);
r = dma_fence_add_callback(fence, &s_fence->cb,
drm_sched_process_job);
if (r == -ENOENT)
drm_sched_process_job(fence, &s_fence->cb);
else if (r)
DRM_ERROR("fence add callback failed (%d)\n",
r);
dma_fence_put(fence);
} else {
drm_sched_process_job(NULL, &s_fence->cb);
}
spin_lock(&sched->job_list_lock);
}
spin_unlock(&sched->job_list_lock);
}
EXPORT_SYMBOL(drm_sched_job_recovery);
/**
* 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 = 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_WORK(&job->finish_work, drm_sched_job_finish);
INIT_LIST_HEAD(&job->node);
INIT_DELAYED_WORK(&job->work_tdr, drm_sched_job_timedout);
return 0;
}
EXPORT_SYMBOL(drm_sched_job_init);
/**
* 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
*
*/
static 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_fence *s_fence =
container_of(cb, struct drm_sched_fence, cb);
struct drm_gpu_scheduler *sched = s_fence->sched;
dma_fence_get(&s_fence->finished);
atomic_dec(&sched->hw_rq_count);
atomic_dec(&sched->num_jobs);
drm_sched_fence_finished(s_fence);
trace_drm_sched_process_job(s_fence);
dma_fence_put(&s_fence->finished);
wake_up_interruptible(&sched->wake_up_worker);
}
/**
* 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;
wait_event_interruptible(sched->wake_up_worker,
(!drm_sched_blocked(sched) &&
(entity = drm_sched_select_entity(sched))) ||
kthread_should_stop());
if (!entity)
continue;
sched_job = drm_sched_entity_pop_job(entity);
if (!sched_job)
continue;
s_fence = sched_job->s_fence;
atomic_inc(&sched->hw_rq_count);
drm_sched_job_begin(sched_job);
fence = sched->ops->run_job(sched_job);
drm_sched_fence_scheduled(s_fence);
if (fence) {
s_fence->parent = dma_fence_get(fence);
r = dma_fence_add_callback(fence, &s_fence->cb,
drm_sched_process_job);
if (r == -ENOENT)
drm_sched_process_job(fence, &s_fence->cb);
else if (r)
DRM_ERROR("fence add callback failed (%d)\n",
r);
dma_fence_put(fence);
} else {
drm_sched_process_job(NULL, &s_fence->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;
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);
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)) {
DRM_ERROR("Failed to create scheduler for %s.\n", name);
return PTR_ERR(sched->thread);
}
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);
}
EXPORT_SYMBOL(drm_sched_fini);
