[Intel-gfx] [PATCH 4/4] drm/i915: Tweak scheduler's kick_submission()

[Chris Wilson]

Skip useless priority bumping on adding a new dependency, but otherwise
prevent tasklet scheduling until we have completed all the potential
rescheduling.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_scheduler.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index 1937a26d412f..ad6ff52bc316 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -216,12 +216,13 @@ static void kick_submission(struct intel_engine_cs *engine,
 	if (inflight->hw_context == rq->hw_context)
 		goto unlock;
 
-	engine->execlists.queue_priority_hint = prio;
 	if (need_preempt(prio, rq_prio(inflight)))
 		tasklet_hi_schedule(&engine->execlists.tasklet);
 
 unlock:
 	rcu_read_unlock();
+
+	engine->execlists.queue_priority_hint = prio;
 }
 
 static void __i915_schedule(struct i915_sched_node *node,
@@ -365,6 +366,9 @@ static void __bump_priority(struct i915_sched_node *node, unsigned int bump)
 {
 	struct i915_sched_attr attr = node->attr;
 
+	if (attr.priority & bump)
+		return;
+
 	attr.priority |= bump;
 	__i915_schedule(node, &attr);
 }
@@ -463,11 +467,15 @@ int i915_sched_node_add_dependency(struct i915_sched_node *node,
 	if (!dep)
 		return -ENOMEM;
 
+	local_bh_disable();
+
 	if (!__i915_sched_node_add_dependency(node, signal, dep,
 					      I915_DEPENDENCY_EXTERNAL |
 					      I915_DEPENDENCY_ALLOC))
 		i915_dependency_free(dep);
 
+	local_bh_enable(); /* kick submission tasklet */
+
 	return 0;
 }
 
-- 
2.24.0