/*
* 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 void drm_sched_process_job(struct dma_fence *f, struct dma_fence_cb *cb);
/**
* drm_sched_rq_init - initialize a given run queue struct
*
* @rq: scheduler run queue
*
* Initializes a scheduler runqueue.
*/
static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
struct drm_sched_rq *rq)
{
spin_lock_init(&rq->lock);
INIT_LIST_HEAD(&rq->entities);
rq->current_entity = NULL;
rq->sched = sched;
}
/**
* drm_sched_rq_add_entity - add an entity
*
* @rq: scheduler run queue
* @entity: scheduler entity
*
* Adds a scheduler entity to the run queue.
*/
void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity)
{
if (!list_empty(&entity->list))
return;
spin_lock(&rq->lock);
list_add_tail(&entity->list, &rq->entities);
spin_unlock(&rq->lock);
}
/**
* drm_sched_rq_remove_entity - remove an entity
*
* @rq: scheduler run queue
* @entity: scheduler entity
*
* Removes a scheduler entity from the run queue.
*/
void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity)
{
if (list_empty(&entity->list))
return;
spin_lock(&rq->lock);
list_del_init(&entity->list);
if (rq->current_entity == entity)
rq->current_entity = NULL;
spin_unlock(&rq->lock);
}
/**
* drm_sched_rq_select_entity - Select an entity which could provide a job to run
*
* @rq: scheduler run queue to check.
*
* Try to find a ready entity, returns NULL if none found.
*/
static struct drm_sched_entity *
drm_sched_rq_select_entity(struct drm_sched_rq *rq)
{
struct drm_sched_entity *entity;
spin_lock(&rq->lock);
entity = rq->current_entity;
if (entity) {
list_for_each_entry_continue(entity, &rq->entities, list) {
if (drm_sched_entity_is_ready(entity)) {
rq->current_entity = entity;
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_dependency_optimized
*
* @fence: the dependency fence
* @entity: the entity which depends on the above fence
*
* Returns true if the dependency can be optimized and false otherwise
*/
bool drm_sched_dependency_optimized(struct dma_fence* fence,
struct drm_sched_entity *entity)
{
struct drm_gpu_scheduler *sched = entity->rq->sched;
struct drm_sched_fence *s_fence;
if (!fence || dma_fence_is_signaled(fence))
return false;
if (fence->context == entity->fence_context)
return true;
s_fence = to_drm_sched_fence(fence);
if (s_fence && s_fence->sched == sched)
return true;
return false;
}
EXPORT_SYMBOL(drm_sched_dependency_optimized);
/**
* drm_sched_start_timeout - start timeout for reset worker
*
* @sched: scheduler instance to start the worker for
*
* Start the timeout for the given scheduler.
*/
static void drm_sched_start_timeout(struct drm_gpu_scheduler *sched)
{
if (sched->timeout != MAX_SCHEDULE_TIMEOUT &&
!list_empty(&sched->ring_mirror_list))
schedule_delayed_work(&sched->work_tdr, sched->timeout);
}
/**
* drm_sched_fault - immediately start timeout handler
*
* @sched: scheduler where the timeout handling should be started.
*
* Start timeout handling immediately when the driver detects a hardware fault.
*/
void drm_sched_fault(struct drm_gpu_scheduler *sched)
{
mod_delayed_work(system_wq, &sched->work_tdr, 0);
}
EXPORT_SYMBOL(drm_sched_fault);
/* 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(&sched->work_tdr);
spin_lock(&sched->job_list_lock);
/* remove job from ring_mirror_list */
list_del(&s_job->node);
/* queue TDR for next job */
drm_sched_start_timeout(sched);
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);
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;
int r;
sched = container_of(work, struct drm_gpu_scheduler, work_tdr.work);
spin_lock(&sched->job_list_lock);
list_for_each_entry_reverse(job, &sched->ring_mirror_list, node) {
struct drm_sched_fence *fence = job->s_fence;
if (!dma_fence_remove_callback(fence->parent, &fence->cb))
goto already_signaled;
}
job = list_first_entry_or_null(&sched->ring_mirror_list,
struct drm_sched_job, node);
spin_unlock(&sched->job_list_lock);
if (job)
sched->ops->timedout_job(job);
spin_lock(&sched->job_list_lock);
list_for_each_entry(job, &sched->ring_mirror_list, node) {
struct drm_sched_fence *fence = job->s_fence;
if (!fence->parent || !list_empty(&fence->cb.node))
continue;
r = dma_fence_add_callback(fence->parent, &fence->cb,
drm_sched_process_job);
if (r)
drm_sched_process_job(fence->parent, &fence->cb);
already_signaled:
;
}
drm_sched_start_timeout(sched);
spin_unlock(&sched->job_list_lock);
}
/**
* 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);
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);
}
drm_sched_start_timeout(sched);
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;
drm_sched_entity_select_rq(entity);
if (!entity->rq)
return -ENOENT;
sched = entity->rq->sched;
job->sched = sched;
job->entity = entity;
job->s_priority = entity->rq - sched->sched_rq;
job->s_fence = drm_sched_fence_create(entity, owner);
if (!job->s_fence)
return -ENOMEM;
job->id = atomic64_inc_return(&sched->job_id_count);
INIT_WORK(&job->finish_work, drm_sched_job_finish);
INIT_LIST_HEAD(&job->node);
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
*
*/
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);
INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
atomic_set(&sched->num_jobs, 0);
atomic64_set(&sched->job_id_count, 0);
/* Each scheduler will run on a seperate kernel thread */
sched->thread = kthread_run(drm_sched_main, sched, sched->name);
if (IS_ERR(sched->thread)) {
DRM_ERROR("Failed to create scheduler for %s.\n", name);
return PTR_ERR(sched->thread);
}
sched->ready = true;
return 0;
}
EXPORT_SYMBOL(drm_sched_init);
/**
* drm_sched_fini - Destroy a gpu scheduler
*
* @sched: scheduler instance
*
* Tears down and cleans up the scheduler.
*/
void drm_sched_fini(struct drm_gpu_scheduler *sched)
{
if (sched->thread)
kthread_stop(sched->thread);
sched->ready = false;
}
EXPORT_SYMBOL(drm_sched_fini);
