[v4,04/40] drm/sched: Add enqueue credit limit

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index dc0e60d2c14b..c5f688362a34 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -580,11 +580,21 @@  void drm_sched_entity_select_rq(struct drm_sched_entity *entity)
  * under common lock for the struct drm_sched_entity that was set up for
  * @sched_job in drm_sched_job_init().
  */
-void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
+int drm_sched_entity_push_job(struct drm_sched_job *sched_job)
 {
 	struct drm_sched_entity *entity = sched_job->entity;
+	struct drm_gpu_scheduler *sched = sched_job->sched;
 	bool first;
 	ktime_t submit_ts;
+	int ret;
+
+	ret = wait_event_interruptible(
+			sched->job_scheduled,
+			atomic_read(&sched->enqueue_credit_count) <=
+			sched->enqueue_credit_limit);
+	if (ret)
+		return ret;
+	atomic_add(sched_job->enqueue_credits, &sched->enqueue_credit_count);
 
 	trace_drm_sched_job(sched_job, entity);
 	atomic_inc(entity->rq->sched->score);
@@ -609,7 +619,7 @@  void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
 			spin_unlock(&entity->lock);
 
 			DRM_ERROR("Trying to push to a killed entity\n");
-			return;
+			return -EINVAL;
 		}
 
 		rq = entity->rq;
@@ -626,5 +636,7 @@  void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
 
 		drm_sched_wakeup(sched);
 	}
+
+	return 0;
 }
 EXPORT_SYMBOL(drm_sched_entity_push_job);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 9412bffa8c74..1102cca69cb4 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -1217,6 +1217,7 @@  static void drm_sched_run_job_work(struct work_struct *w)
 
 	trace_drm_run_job(sched_job, entity);
 	fence = sched->ops->run_job(sched_job);
+	atomic_sub(sched_job->enqueue_credits, &sched->enqueue_credit_count);
 	complete_all(&entity->entity_idle);
 	drm_sched_fence_scheduled(s_fence, fence);
 
@@ -1253,6 +1254,7 @@  int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
 
 	sched->ops = args->ops;
 	sched->credit_limit = args->credit_limit;
+	sched->enqueue_credit_limit = args->enqueue_credit_limit;
 	sched->name = args->name;
 	sched->timeout = args->timeout;
 	sched->hang_limit = args->hang_limit;
@@ -1308,6 +1310,7 @@  int drm_sched_init(struct drm_gpu_scheduler *sched, const struct drm_sched_init_
 	INIT_LIST_HEAD(&sched->pending_list);
 	spin_lock_init(&sched->job_list_lock);
 	atomic_set(&sched->credit_count, 0);
+	atomic_set(&sched->enqueue_credit_count, 0);
 	INIT_DELAYED_WORK(&sched->work_tdr, drm_sched_job_timedout);
 	INIT_WORK(&sched->work_run_job, drm_sched_run_job_work);
 	INIT_WORK(&sched->work_free_job, drm_sched_free_job_work);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index da64232c989d..d830ffe083f1 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -329,6 +329,7 @@  struct drm_sched_fence *to_drm_sched_fence(struct dma_fence *f);
  * @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
+ * @enqueue_credits: the number of enqueue credits this job contributes
  * @work: Helper to reschedule 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
@@ -366,6 +367,7 @@  struct drm_sched_job {
 
 	enum drm_sched_priority		s_priority;
 	u32				credits;
+	u32				enqueue_credits;
 	/** @last_dependency: tracks @dependencies as they signal */
 	unsigned int			last_dependency;
 	atomic_t			karma;
@@ -485,6 +487,10 @@  struct drm_sched_backend_ops {
  * @ops: backend operations provided by the driver.
  * @credit_limit: the credit limit of this scheduler
  * @credit_count: the current credit count of this scheduler
+ * @enqueue_credit_limit: the credit limit of jobs pushed to scheduler and not
+ *                        yet run
+ * @enqueue_credit_count: the current crdit count of jobs pushed to scheduler
+ *                        but not yet run
  * @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,
@@ -518,6 +524,8 @@  struct drm_gpu_scheduler {
 	const struct drm_sched_backend_ops	*ops;
 	u32				credit_limit;
 	atomic_t			credit_count;
+	u32				enqueue_credit_limit;
+	atomic_t			enqueue_credit_count;
 	long				timeout;
 	const char			*name;
 	u32                             num_rqs;
@@ -550,6 +558,8 @@  struct drm_gpu_scheduler {
  * @num_rqs: Number of run-queues. This may be at most DRM_SCHED_PRIORITY_COUNT,
  *	     as there's usually one run-queue per priority, but may be less.
  * @credit_limit: the number of credits this scheduler can hold from all jobs
+ * @enqueue_credit_limit: the number of credits that can be enqueued before
+ *                        drm_sched_entity_push_job() blocks
  * @hang_limit: number of times to allow a job to hang before dropping it.
  *		This mechanism is DEPRECATED. Set it to 0.
  * @timeout: timeout value in jiffies for submitted jobs.
@@ -564,6 +574,7 @@  struct drm_sched_init_args {
 	struct workqueue_struct *timeout_wq;
 	u32 num_rqs;
 	u32 credit_limit;
+	u32 enqueue_credit_limit;
 	unsigned int hang_limit;
 	long timeout;
 	atomic_t *score;
@@ -600,7 +611,7 @@  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);
-void drm_sched_entity_push_job(struct drm_sched_job *sched_job);
+int drm_sched_entity_push_job(struct drm_sched_job *sched_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,