From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx>
In FIFO mode (which is the default), both drm_sched_entity_push_job() and
drm_sched_rq_update_fifo(), where the latter calls the former, are
currently taking and releasing the same entity->rq_lock.
We can avoid that design inelegance, and also have a miniscule
efficiency improvement on the submit from idle path, by introducing a new
drm_sched_rq_update_fifo_locked() helper and pulling up the lock taking to
its callers.
v2:
* Remove drm_sched_rq_update_fifo() altogether. (Christian)
v3:
* Improved commit message. (Philipp)
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>
Reviewed-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/scheduler/sched_entity.c | 13 +++++++++----
drivers/gpu/drm/scheduler/sched_main.c | 6 +++---
include/drm/gpu_scheduler.h | 2 +-
3 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/scheduler/sched_entity.c b/drivers/gpu/drm/scheduler/sched_entity.c
index 2951fcc2e6b1..b72cba292839 100644
--- a/drivers/gpu/drm/scheduler/sched_entity.c
+++ b/drivers/gpu/drm/scheduler/sched_entity.c
@@ -514,8 +514,12 @@ struct drm_sched_job *drm_sched_entity_pop_job(struct drm_sched_entity *entity)
struct drm_sched_job *next;
next = to_drm_sched_job(spsc_queue_peek(&entity->job_queue));
- if (next)
- drm_sched_rq_update_fifo(entity, next->submit_ts);
+ if (next) {
+ spin_lock(&entity->rq_lock);
+ drm_sched_rq_update_fifo_locked(entity,
+ next->submit_ts);
+ spin_unlock(&entity->rq_lock);
+ }
}
/* Jobs and entities might have different lifecycles. Since we're
@@ -613,10 +617,11 @@ void drm_sched_entity_push_job(struct drm_sched_job *sched_job)
sched = rq->sched;
drm_sched_rq_add_entity(rq, entity);
- spin_unlock(&entity->rq_lock);
if (drm_sched_policy == DRM_SCHED_POLICY_FIFO)
- drm_sched_rq_update_fifo(entity, submit_ts);
+ drm_sched_rq_update_fifo_locked(entity, submit_ts);
+
+ spin_unlock(&entity->rq_lock);
drm_sched_wakeup(sched);
}
diff --git a/drivers/gpu/drm/scheduler/sched_main.c b/drivers/gpu/drm/scheduler/sched_main.c
index e32b0f7d7e94..bbd1630407e4 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -169,14 +169,15 @@ static inline void drm_sched_rq_remove_fifo_locked(struct drm_sched_entity *enti
}
}
-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)
{
/*
* 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->rq_lock);
+ lockdep_assert_held(&entity->rq_lock);
+
spin_lock(&entity->rq->lock);
drm_sched_rq_remove_fifo_locked(entity);
@@ -187,7 +188,6 @@ void drm_sched_rq_update_fifo(struct drm_sched_entity *entity, ktime_t ts)
drm_sched_entity_compare_before);
spin_unlock(&entity->rq->lock);
- spin_unlock(&entity->rq_lock);
}
/**
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index e9f075f51db3..3658a6cb048e 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -593,7 +593,7 @@ 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_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);
int drm_sched_entity_init(struct drm_sched_entity *entity,
enum drm_sched_priority priority,
--
2.46.0
