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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.
*
*/
#ifndef _DRM_GPU_SCHEDULER_H_
#define _DRM_GPU_SCHEDULER_H_
#include <drm/spsc_queue.h>
#include <linux/dma-fence.h>
#include <linux/completion.h>
#include <linux/xarray.h>
#include <linux/workqueue.h>
#define MAX_WAIT_SCHED_ENTITY_Q_EMPTY msecs_to_jiffies(1000)
/**
* DRM_SCHED_FENCE_DONT_PIPELINE - Prefent dependency pipelining
*
* Setting this flag on a scheduler fence prevents pipelining of jobs depending
* on this fence. In other words we always insert a full CPU round trip before
* dependen jobs are pushed to the hw queue.
*/
#define DRM_SCHED_FENCE_DONT_PIPELINE DMA_FENCE_FLAG_USER_BITS
/**
* DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT - A fence deadline hint has been set
*
* Because we could have a deadline hint can be set before the backing hw
* fence is created, we need to keep track of whether a deadline has already
* been set.
*/
#define DRM_SCHED_FENCE_FLAG_HAS_DEADLINE_BIT (DMA_FENCE_FLAG_USER_BITS + 1)
enum dma_resv_usage;
struct dma_resv;
struct drm_gem_object;
struct drm_gpu_scheduler;
struct drm_sched_rq;
struct drm_file;
/* These are often used as an (initial) index
* to an array, and as such should start at 0.
*/
enum drm_sched_priority {
DRM_SCHED_PRIORITY_KERNEL,
DRM_SCHED_PRIORITY_HIGH,
DRM_SCHED_PRIORITY_NORMAL,
DRM_SCHED_PRIORITY_LOW,
DRM_SCHED_PRIORITY_COUNT
};
/* Used to chose between FIFO and RR jobs scheduling */
extern int drm_sched_policy;
#define DRM_SCHED_POLICY_RR 0
#define DRM_SCHED_POLICY_FIFO 1
/**
* struct drm_sched_entity - A wrapper around a job queue (typically
* attached to the DRM file_priv).
*
* Entities will emit jobs in order to their corresponding hardware
* ring, and the scheduler will alternate between entities based on
* scheduling policy.
*/
struct drm_sched_entity {
/**
* @list:
*
* Used to append this struct to the list of entities in the runqueue
* @rq under &drm_sched_rq.entities.
*
* Protected by &drm_sched_rq.lock of @rq.
*/
struct list_head list;
/**
* @rq:
*
* Runqueue on which this entity is currently scheduled.
*
* FIXME: Locking is very unclear for this. Writers are protected by
* @rq_lock, but readers are generally lockless and seem to just race
* with not even a READ_ONCE.
*/
struct drm_sched_rq *rq;
/**
* @sched_list:
*
* A list of schedulers (struct drm_gpu_scheduler). Jobs from this entity can
* be scheduled on any scheduler on this list.
*
* This can be modified by calling drm_sched_entity_modify_sched().
* Locking is entirely up to the driver, see the above function for more
* details.
*
* This will be set to NULL if &num_sched_list equals 1 and @rq has been
* set already.
*
* FIXME: This means priority changes through
* drm_sched_entity_set_priority() will be lost henceforth in this case.
*/
struct drm_gpu_scheduler **sched_list;
/**
* @num_sched_list:
*
* Number of drm_gpu_schedulers in the @sched_list.
*/
unsigned int num_sched_list;
/**
* @priority:
*
* Priority of the entity. This can be modified by calling
* drm_sched_entity_set_priority(). Protected by &rq_lock.
*/
enum drm_sched_priority priority;
/**
* @rq_lock:
*
* Lock to modify the runqueue to which this entity belongs.
*/
spinlock_t rq_lock;
/**
* @job_queue: the list of jobs of this entity.
*/
struct spsc_queue job_queue;
/**
* @fence_seq:
*
* A linearly increasing seqno incremented with each new
* &drm_sched_fence which is part of the entity.
*
* FIXME: Callers of drm_sched_job_arm() need to ensure correct locking,
* this doesn't need to be atomic.
*/
atomic_t fence_seq;
/**
* @fence_context:
*
* A unique context for all the fences which belong to this entity. The
* &drm_sched_fence.scheduled uses the fence_context but
* &drm_sched_fence.finished uses fence_context + 1.
*/
uint64_t fence_context;
/**
* @dependency:
*
* The dependency fence of the job which is on the top of the job queue.
*/
struct dma_fence *dependency;
/**
* @cb:
*
* Callback for the dependency fence above.
*/
struct dma_fence_cb cb;
/**
* @guilty:
*
* Points to entities' guilty.
*/
atomic_t *guilty;
/**
* @last_scheduled:
*
* Points to the finished fence of the last scheduled job. Only written
* by the scheduler thread, can be accessed locklessly from
* drm_sched_job_arm() iff the queue is empty.
*/
struct dma_fence __rcu *last_scheduled;
/**
* @last_user: last group leader pushing a job into the entity.
*/
struct task_struct *last_user;
/**
* @stopped:
*
* Marks the enity as removed from rq and destined for
* termination. This is set by calling drm_sched_entity_flush() and by
* drm_sched_fini().
*/
bool stopped;
/**
* @entity_idle:
*
* Signals when entity is not in use, used to sequence entity cleanup in
* drm_sched_entity_fini().
*/
struct completion entity_idle;
/**
* @oldest_job_waiting:
*
* Marks earliest job waiting in SW queue
*/
ktime_t oldest_job_waiting;
/**
* @rb_tree_node:
*
* The node used to insert this entity into time based priority queue
*/
struct rb_node rb_tree_node;
};
/**
* struct drm_sched_rq - queue of entities to be scheduled.
*
* @lock: to modify the entities list.
* @sched: the scheduler to which this rq belongs to.
* @entities: list of the entities to be scheduled.
* @current_entity: the entity which is to be scheduled.
* @rb_tree_root: root of time based priory queue of entities for FIFO scheduling
*
* Run queue is a set of entities scheduling command submissions for
* one specific ring. It implements the scheduling policy that selects
* the next entity to emit commands from.
*/
struct drm_sched_rq {
spinlock_t lock;
struct drm_gpu_scheduler *sched;
struct list_head entities;
struct drm_sched_entity *current_entity;
struct rb_root_cached rb_tree_root;
};
/**
* struct drm_sched_fence - fences corresponding to the scheduling of a job.
*/
struct drm_sched_fence {
/**
* @scheduled: this fence is what will be signaled by the scheduler
* when the job is scheduled.
*/
struct dma_fence scheduled;
/**
* @finished: this fence is what will be signaled by the scheduler
* when the job is completed.
*
* When setting up an out fence for the job, you should use
* this, since it's available immediately upon
* drm_sched_job_init(), and the fence returned by the driver
* from run_job() won't be created until the dependencies have
* resolved.
*/
struct dma_fence finished;
/**
* @deadline: deadline set on &drm_sched_fence.finished which
* potentially needs to be propagated to &drm_sched_fence.parent
*/
ktime_t deadline;
/**
* @parent: the fence returned by &drm_sched_backend_ops.run_job
* when scheduling the job on hardware. We signal the
* &drm_sched_fence.finished fence once parent is signalled.
*/
struct dma_fence *parent;
/**
* @sched: the scheduler instance to which the job having this struct
* belongs to.
*/
struct drm_gpu_scheduler *sched;
/**
* @lock: the lock used by the scheduled and the finished fences.
*/
spinlock_t lock;
/**
* @owner: job owner for debugging
*/
void *owner;
};
struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);
/**
* struct drm_sched_job - A job to be run by an entity.
*
* @queue_node: used to append this struct to the queue of jobs in an entity.
* @list: a job participates in a "pending" and "done" lists.
* @sched: the scheduler instance on which this job is scheduled.
* @s_fence: contains the fences for the scheduling of job.
* @finish_cb: the callback for the finished fence.
* @credits: the number of credits this job contributes to the scheduler
* @work: Helper to reschdeule job kill to different context.
* @id: a unique id assigned to each job scheduled on the scheduler.
* @karma: increment on every hang caused by this job. If this exceeds the hang
* limit of the scheduler then the job is marked guilty and will not
* be scheduled further.
* @s_priority: the priority of the job.
* @entity: the entity to which this job belongs.
* @cb: the callback for the parent fence in s_fence.
*
* A job is created by the driver using drm_sched_job_init(), and
* should call drm_sched_entity_push_job() once it wants the scheduler
* to schedule the job.
*/
struct drm_sched_job {
struct spsc_node queue_node;
struct list_head list;
struct drm_gpu_scheduler *sched;
struct drm_sched_fence *s_fence;
u32 credits;
/*
* work is used only after finish_cb has been used and will not be
* accessed anymore.
*/
union {
struct dma_fence_cb finish_cb;
struct work_struct work;
};
uint64_t id;
atomic_t karma;
enum drm_sched_priority s_priority;
struct drm_sched_entity *entity;
struct dma_fence_cb cb;
/**
* @dependencies:
*
* Contains the dependencies as struct dma_fence for this job, see
* drm_sched_job_add_dependency() and
* drm_sched_job_add_implicit_dependencies().
*/
struct xarray dependencies;
/** @last_dependency: tracks @dependencies as they signal */
unsigned long last_dependency;
/**
* @submit_ts:
*
* When the job was pushed into the entity queue.
*/
ktime_t submit_ts;
};
static inline bool drm_sched_invalidate_job(struct drm_sched_job *s_job,
int threshold)
{
return s_job && atomic_inc_return(&s_job->karma) > threshold;
}
enum drm_gpu_sched_stat {
DRM_GPU_SCHED_STAT_NONE, /* Reserve 0 */
DRM_GPU_SCHED_STAT_NOMINAL,
DRM_GPU_SCHED_STAT_ENODEV,
};
/**
* struct drm_sched_backend_ops - Define the backend operations
* called by the scheduler
*
* These functions should be implemented in the driver side.
*/
struct drm_sched_backend_ops {
/**
* @prepare_job:
*
* Called when the scheduler is considering scheduling this job next, to
* get another struct dma_fence for this job to block on. Once it
* returns NULL, run_job() may be called.
*
* Can be NULL if no additional preparation to the dependencies are
* necessary. Skipped when jobs are killed instead of run.
*/
struct dma_fence *(*prepare_job)(struct drm_sched_job *sched_job,
struct drm_sched_entity *s_entity);
/**
* @run_job: Called to execute the job once all of the dependencies
* have been resolved. This may be called multiple times, if
* timedout_job() has happened and drm_sched_job_recovery()
* decides to try it again.
*/
struct dma_fence *(*run_job)(struct drm_sched_job *sched_job);
/**
* @timedout_job: Called when a job has taken too long to execute,
* to trigger GPU recovery.
*
* This method is called in a workqueue context.
*
* Drivers typically issue a reset to recover from GPU hangs, and this
* procedure usually follows the following workflow:
*
* 1. Stop the scheduler using drm_sched_stop(). This will park the
* scheduler thread and cancel the timeout work, guaranteeing that
* nothing is queued while we reset the hardware queue
* 2. Try to gracefully stop non-faulty jobs (optional)
* 3. Issue a GPU reset (driver-specific)
* 4. Re-submit jobs using drm_sched_resubmit_jobs()
* 5. Restart the scheduler using drm_sched_start(). At that point, new
* jobs can be queued, and the scheduler thread is unblocked
*
* Note that some GPUs have distinct hardware queues but need to reset
* the GPU globally, which requires extra synchronization between the
* timeout handler of the different &drm_gpu_scheduler. One way to
* achieve this synchronization is to create an ordered workqueue
* (using alloc_ordered_workqueue()) at the driver level, and pass this
* queue to drm_sched_init(), to guarantee that timeout handlers are
* executed sequentially. The above workflow needs to be slightly
* adjusted in that case:
*
* 1. Stop all schedulers impacted by the reset using drm_sched_stop()
* 2. Try to gracefully stop non-faulty jobs on all queues impacted by
* the reset (optional)
* 3. Issue a GPU reset on all faulty queues (driver-specific)
* 4. Re-submit jobs on all schedulers impacted by the reset using
* drm_sched_resubmit_jobs()
* 5. Restart all schedulers that were stopped in step #1 using
* drm_sched_start()
*
* Return DRM_GPU_SCHED_STAT_NOMINAL, when all is normal,
* and the underlying driver has started or completed recovery.
*
* Return DRM_GPU_SCHED_STAT_ENODEV, if the device is no longer
* available, i.e. has been unplugged.
*/
enum drm_gpu_sched_stat (*timedout_job)(struct drm_sched_job *sched_job);
/**
* @free_job: Called once the job's finished fence has been signaled
* and it's time to clean it up.
*/
void (*free_job)(struct drm_sched_job *sched_job);
/**
* @update_job_credits: Called when the scheduler is considering this
* job for execution.
*
* This callback returns the number of credits the job would take if
* pushed to the hardware. Drivers may use this to dynamically update
* the job's credit count. For instance, deduct the number of credits
* for already signalled native fences.
*
* This callback is optional.
*/
u32 (*update_job_credits)(struct drm_sched_job *sched_job);
};
/**
* struct drm_gpu_scheduler - scheduler instance-specific data
*
* @ops: backend operations provided by the driver.
* @credit_limit: the credit limit of this scheduler
* @credit_count: the current credit count of this scheduler
* @timeout: the time after which a job is removed from the scheduler.
* @name: name of the ring for which this scheduler is being used.
* @num_rqs: Number of run-queues. This is at most DRM_SCHED_PRIORITY_COUNT,
* as there's usually one run-queue per priority, but could be less.
* @sched_rq: An allocated array of run-queues of size @num_rqs;
* @job_scheduled: once @drm_sched_entity_do_release is called the scheduler
* waits on this wait queue until all the scheduled jobs are
* finished.
* @job_id_count: used to assign unique id to the each job.
* @submit_wq: workqueue used to queue @work_run_job and @work_free_job
* @timeout_wq: workqueue used to queue @work_tdr
* @work_run_job: work which calls run_job op of each scheduler.
* @work_free_job: work which calls free_job op of each scheduler.
* @work_tdr: schedules a delayed call to @drm_sched_job_timedout after the
* timeout interval is over.
* @pending_list: the list of jobs which are currently in the job queue.
* @job_list_lock: lock to protect the pending_list.
* @hang_limit: once the hangs by a job crosses this limit then it is marked
* guilty and it will no longer be considered for scheduling.
* @score: score to help loadbalancer pick a idle sched
* @_score: score used when the driver doesn't provide one
* @ready: marks if the underlying HW is ready to work
* @free_guilty: A hit to time out handler to free the guilty job.
* @pause_submit: pause queuing of @work_run_job on @submit_wq
* @own_submit_wq: scheduler owns allocation of @submit_wq
* @dev: system &struct device
*
* One scheduler is implemented for each hardware ring.
*/
struct drm_gpu_scheduler {
const struct drm_sched_backend_ops *ops;
u32 credit_limit;
atomic_t credit_count;
long timeout;
const char *name;
u32 num_rqs;
struct drm_sched_rq **sched_rq;
wait_queue_head_t job_scheduled;
atomic64_t job_id_count;
struct workqueue_struct *submit_wq;
struct workqueue_struct *timeout_wq;
struct work_struct work_run_job;
struct work_struct work_free_job;
struct delayed_work work_tdr;
struct list_head pending_list;
spinlock_t job_list_lock;
int hang_limit;
atomic_t *score;
atomic_t _score;
bool ready;
bool free_guilty;
bool pause_submit;
bool own_submit_wq;
struct device *dev;
};
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);
void drm_sched_fini(struct drm_gpu_scheduler *sched);
int drm_sched_job_init(struct drm_sched_job *job,
struct drm_sched_entity *entity,
u32 credits, void *owner);
void drm_sched_job_arm(struct drm_sched_job *job);
int drm_sched_job_add_dependency(struct drm_sched_job *job,
struct dma_fence *fence);
int drm_sched_job_add_syncobj_dependency(struct drm_sched_job *job,
struct drm_file *file,
u32 handle,
u32 point);
int drm_sched_job_add_resv_dependencies(struct drm_sched_job *job,
struct dma_resv *resv,
enum dma_resv_usage usage);
int drm_sched_job_add_implicit_dependencies(struct drm_sched_job *job,
struct drm_gem_object *obj,
bool write);
void drm_sched_entity_modify_sched(struct drm_sched_entity *entity,
struct drm_gpu_scheduler **sched_list,
unsigned int num_sched_list);
void drm_sched_tdr_queue_imm(struct drm_gpu_scheduler *sched);
void drm_sched_job_cleanup(struct drm_sched_job *job);
void drm_sched_wakeup(struct drm_gpu_scheduler *sched);
bool drm_sched_wqueue_ready(struct drm_gpu_scheduler *sched);
void drm_sched_wqueue_stop(struct drm_gpu_scheduler *sched);
void drm_sched_wqueue_start(struct drm_gpu_scheduler *sched);
void drm_sched_stop(struct drm_gpu_scheduler *sched, struct drm_sched_job *bad);
void drm_sched_start(struct drm_gpu_scheduler *sched, bool full_recovery);
void drm_sched_resubmit_jobs(struct drm_gpu_scheduler *sched);
void drm_sched_increase_karma(struct drm_sched_job *bad);
void drm_sched_reset_karma(struct drm_sched_job *bad);
void drm_sched_increase_karma_ext(struct drm_sched_job *bad, int type);
bool drm_sched_dependency_optimized(struct dma_fence* fence,
struct drm_sched_entity *entity);
void drm_sched_fault(struct drm_gpu_scheduler *sched);
void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity);
void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
struct drm_sched_entity *entity);
void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts);
int drm_sched_entity_init(struct drm_sched_entity *entity,
enum drm_sched_priority priority,
struct drm_gpu_scheduler **sched_list,
unsigned int num_sched_list,
atomic_t *guilty);
long drm_sched_entity_flush(struct drm_sched_entity *entity, long timeout);
void drm_sched_entity_fini(struct drm_sched_entity *entity);
void drm_sched_entity_destroy(struct drm_sched_entity *entity);
void drm_sched_entity_select_rq(struct drm_sched_entity *entity);
struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity);
void drm_sched_entity_push_job(struct drm_sched_job *sched_job);
void drm_sched_entity_set_priority(struct drm_sched_entity *entity,
enum drm_sched_priority priority);
bool drm_sched_entity_is_ready(struct drm_sched_entity *entity);
int drm_sched_entity_error(struct drm_sched_entity *entity);
struct drm_sched_fence *drm_sched_fence_alloc(
struct drm_sched_entity *s_entity, void *owner);
void drm_sched_fence_init(struct drm_sched_fence *fence,
struct drm_sched_entity *entity);
void drm_sched_fence_free(struct drm_sched_fence *fence);
void drm_sched_fence_scheduled(struct drm_sched_fence *fence,
struct dma_fence *parent);
void drm_sched_fence_finished(struct drm_sched_fence *fence, int result);
unsigned long drm_sched_suspend_timeout(struct drm_gpu_scheduler *sched);
void drm_sched_resume_timeout(struct drm_gpu_scheduler *sched,
unsigned long remaining);
struct drm_gpu_scheduler *
drm_sched_pick_best(struct drm_gpu_scheduler **sched_list,
unsigned int num_sched_list);
#endif
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