From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
Having removed one re-lock cycle on the entity->lock in a patch titled
"drm/sched: Optimise drm_sched_entity_push_job", with only a tiny bit
larger refactoring we can do the same optimisation on the rq->lock.
(Currently both drm_sched_rq_add_entity() and
drm_sched_rq_update_fifo_locked() take and release the same lock.)
To achieve this we rename drm_sched_rq_add_entity() to
drm_sched_rq_add_entity_locked(), making it expect the rq->lock to be
held, and also add the same expectation to
drm_sched_rq_update_fifo_locked().
For more stream-lining we also add the run-queue as an explicit parameter
to drm_sched_rq_remove_fifo_locked() to avoid both callers and callee
having to dereference entity->rq.
Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
Cc: Christian König <christian.koenig@xxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: Luben Tuikov <ltuikov89@xxxxxxxxx>
Cc: Matthew Brost <matthew.brost@xxxxxxxxx>
Cc: Philipp Stanner <pstanner@xxxxxxxxxx>
---
drivers/gpu/drm/scheduler/sched_entity.c | 7 ++--
drivers/gpu/drm/scheduler/sched_main.c | 41 +++++++++++++-----------
include/drm/gpu_scheduler.h | 7 ++--
3 files changed, 31 insertions(+), 24 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index b4c4f9923e0b..2102c726d275 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -614,11 +614,14 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
sched = rq->sched;
atomic_inc(sched->score);
- drm_sched_rq_add_entity(rq, entity);
+
+ spin_lock(&rq->lock);
+ drm_sched_rq_add_entity_locked(rq, entity);
if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- drm_sched_rq_update_fifo_locked(entity, submit_ts);
+ drm_sched_rq_update_fifo_locked(entity, rq, submit_ts);
+ spin_unlock(&rq->lock);
spin_unlock(&entity->lock);
drm_sched_wakeup(sched, entity);
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index 937e7d1cfc49..1ccd2aed2d32 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -153,41 +153,44 @@ 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 inline void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity)
+static void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *entity,
+ struct drm_sched_rq *rq)
{
- struct drm_sched_rq *rq = entity->rq;
-
if (!RB_EMPTY_NODE(&entity->rb_tree_node)) {
rb_erase_cached(&entity->rb_tree_node, &rq->rb_tree_root);
RB_CLEAR_NODE(&entity->rb_tree_node);
}
}
-void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity, ktime_t ts)
+void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
+ struct drm_sched_rq *rq,
+ ktime_t ts)
{
lockdep_assert_held(&entity->lock);
+ lockdep_assert_held(&rq->lock);
- spin_lock(&entity->rq->lock);
-
- drm_sched_rq_remove_fifo_locked(entity);
+ drm_sched_rq_remove_fifo_locked(entity, rq);
entity->oldest_job_waiting = ts;
- rb_add_cached(&entity->rb_tree_node, &entity->rq->rb_tree_root,
+ rb_add_cached(&entity->rb_tree_node, &rq->rb_tree_root,
drm_sched_entity_compare_before);
-
- spin_unlock(&entity->rq->lock);
}
void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts)
{
+ struct drm_sched_rq *rq;
+
/*
* Both locks need to be grabbed, one to protect from entity->rq change
* for entity from within concurrent drm_sched_entity_select_rq and the
* other to update the rb tree structure.
*/
spin_lock(&entity->lock);
- drm_sched_rq_update_fifo_locked(entity, ts);
+ rq = entity->rq;
+ spin_lock(&rq->lock);
+ drm_sched_rq_update_fifo_locked(entity, rq, ts);
+ spin_unlock(&rq->lock);
spin_unlock(&entity->lock);
}
@@ -210,25 +213,23 @@ static void drm_sched_rq_init(struct drm_gpu_scheduler *sched,
}
/**
- * drm_sched_rq_add_entity - add an entity
+ * drm_sched_rq_add_entity_locked - 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)
+void drm_sched_rq_add_entity_locked(struct drm_sched_rq *rq,
+ struct drm_sched_entity *entity)
{
+ lockdep_assert_held(&rq->lock);
+
if (!list_empty(&entity->list))
return;
- spin_lock(&rq->lock);
-
atomic_inc(rq->sched->score);
list_add_tail(&entity->list, &rq->entities);
-
- spin_unlock(&rq->lock);
}
/**
@@ -242,6 +243,8 @@ 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)
{
+ lockdep_assert_held(&entity->lock);
+
if (list_empty(&entity->list))
return;
@@ -254,7 +257,7 @@ void drm_sched_rq_remove_entity(struct drm_sched_rq *rq,
rq->current_entity = NULL;
if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- drm_sched_rq_remove_fifo_locked(entity);
+ drm_sched_rq_remove_fifo_locked(entity, rq);
spin_unlock(&rq->lock);
}
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index 5a1e4c803b90..2ad33e2fe2d2 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -591,13 +591,14 @@ 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_add_entity_locked(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);
-void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity, ktime_t ts);
+void drm_sched_rq_update_fifo_locked(struct drm_sched_entity *entity,
+ struct drm_sched_rq *rq, ktime_t ts);
int drm_sched_entity_init(struct drm_sched_entity *entity,
enum drm_sched_priority priority,
--
2.46.0
