drm/i915/execlists: Don't apply priority boost for resets

Do not treat reset as a normal preemption event and avoid giving the
guilty request a priority boost for simply being active at the time of
reset.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190507122954.6299-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/gt/intel_lrc.c

@@ -371,11 +371,11 @@ static void unwind_wa_tail(struct i915_request *rq)
 }
 
 static struct i915_request *
-__unwind_incomplete_requests(struct intel_engine_cs *engine)
+__unwind_incomplete_requests(struct intel_engine_cs *engine, int boost)
 {
 	struct i915_request *rq, *rn, *active = NULL;
 	struct list_head *uninitialized_var(pl);
-	int prio = I915_PRIORITY_INVALID | ACTIVE_PRIORITY;
+	int prio = I915_PRIORITY_INVALID | boost;
 
 	lockdep_assert_held(&engine->timeline.lock);
 
@@ -419,8 +419,9 @@ __unwind_incomplete_requests(struct intel_engine_cs *engine)
 	 * in the priority queue, but they will not gain immediate access to
 	 * the GPU.
 	 */
-	if (~prio & ACTIVE_PRIORITY && __i915_request_has_started(active)) {
-		prio |= ACTIVE_PRIORITY;
+	if (~prio & boost && __i915_request_has_started(active)) {
+		prio |= boost;
+		GEM_BUG_ON(active->sched.attr.priority >= prio);
 		active->sched.attr.priority = prio;
 		list_move_tail(&active->sched.link,
 			       i915_sched_lookup_priolist(engine, prio));
@@ -435,7 +436,7 @@ execlists_unwind_incomplete_requests(struct intel_engine_execlists *execlists)
 	struct intel_engine_cs *engine =
 		container_of(execlists, typeof(*engine), execlists);
 
-	return __unwind_incomplete_requests(engine);
+	return __unwind_incomplete_requests(engine, 0);
 }
 
 static inline void
@@ -656,7 +657,8 @@ static void complete_preempt_context(struct intel_engine_execlists *execlists)
 	execlists_cancel_port_requests(execlists);
 	__unwind_incomplete_requests(container_of(execlists,
 						  struct intel_engine_cs,
-						  execlists));
+						  execlists),
+				     ACTIVE_PRIORITY);
 }
 
 static void execlists_dequeue(struct intel_engine_cs *engine)
@@ -1909,7 +1911,7 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
 	execlists_cancel_port_requests(execlists);
 
 	/* Push back any incomplete requests for replay after the reset. */
-	rq = __unwind_incomplete_requests(engine);
+	rq = __unwind_incomplete_requests(engine, 0);
 	if (!rq)
 		goto out_replay;