[RFC 09/18] drm/sched: Remove idle entity from tree

[Tvrtko Ursulin]

There is no need to keep entities with no jobs in the tree so lets remove
it once the last job is consumed. This keeps the tree smaller which is
nicer and more efficient.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at igalia.com>
Cc: Christian König <christian.koenig at amd.com>
Cc: Danilo Krummrich <dakr at redhat.com>
Cc: Matthew Brost <matthew.brost at intel.com>
Cc: Philipp Stanner <pstanner at redhat.com>
---
 drivers/gpu/drm/scheduler/sched_entity.c | 15 ++++++++-------
 drivers/gpu/drm/scheduler/sched_main.c   |  4 ++--
 include/drm/gpu_scheduler.h              |  2 ++
 3 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 69bcf0e99d57..8e910586979e 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -512,19 +512,20 @@ struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
 	 */
 	if (drm_sched_policy == DRM_SCHED_POLICY_FIFO) {
 		struct drm_sched_job *next;
+		struct drm_sched_rq *rq;
 
+		spin_lock(&entity->lock);
+		rq = entity->rq;
+		spin_lock(&rq->lock);
 		next = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
 		if (next) {
-			struct drm_sched_rq *rq;
-
-			spin_lock(&entity->lock);
-			rq = entity->rq;
-			spin_lock(&rq->lock);
 			drm_sched_rq_update_fifo_locked(entity, rq,
 							next->submit_ts);
-			spin_unlock(&rq->lock);
-			spin_unlock(&entity->lock);
+		} else {
+			drm_sched_rq_remove_fifo_locked(entity, rq);
 		}
+		spin_unlock(&rq->lock);
+		spin_unlock(&entity->lock);
 	}
 
 	/* Jobs and entities might have different lifecycles. Since we're
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 9a3d31c33fa9..bcfc2abe349a 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -146,8 +146,8 @@ static __always_inline bool drm_sched_entity_compare_before(struct rb_node *a,
 	return ktime_before(ent_a->oldest_job_waiting, ent_b->oldest_job_waiting);
 }
 
-static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
-					    struct drm_sched_rq *rq)
+void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
+				     struct drm_sched_rq *rq)
 {
 	if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
 		rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index a0ff08123f07..005db1e35fad 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -592,6 +592,8 @@ void drm_sched_rq_add_entity(struct drm_sched_rq *rq,
 void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
 				struct drm_sched_entity *entity);
 
+void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
+				     struct drm_sched_rq *rq);
 void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
 				     struct drm_sched_rq *rq, ktime_t ts);
 
-- 
2.47.1