From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Mon, 26 Mar 2018 12:50:34 +0100
Subject: drm/i915/execlists: Avoid kicking the submission too early for
 rescheduling
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Git-commit: ae2f5c009335f4d273d2431539de91c8f28d4736
Patch-mainline: v4.18-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

If the request is still waiting on external fences, it has not yet been
submitted to the HW queue and so we can forgo kicking the submission
tasklet when re-evaluating its priority.

This should have no impact other than reducing the number of tasklet
wakeups under signal heavy workloads (e.g. switching between engines).

v2: Use prebaked container_of()

References: f6322eddaff7 ("drm/i915/preemption: Allow preemption between submission ports")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Michał Winiarski <michal.winiarski@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180326115044.2505-2-chris@chris-wilson.co.uk
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/i915/intel_lrc.c |   17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1061,12 +1061,16 @@ static void queue_request(struct intel_e
 	list_add_tail(&pt->link, &lookup_priolist(engine, pt, prio)->requests);
 }
 
+static void __submit_queue(struct intel_engine_cs *engine, int prio)
+{
+	engine->execlists.queue_priority = prio;
+	tasklet_hi_schedule(&engine->execlists.tasklet);
+}
+
 static void submit_queue(struct intel_engine_cs *engine, int prio)
 {
-	if (prio > engine->execlists.queue_priority) {
-		engine->execlists.queue_priority = prio;
-		tasklet_hi_schedule(&engine->execlists.tasklet);
-	}
+	if (prio > engine->execlists.queue_priority)
+		__submit_queue(engine, prio);
 }
 
 static void execlists_submit_request(struct i915_request *request)
@@ -1199,7 +1203,10 @@ static void execlists_schedule(struct i9
 			__list_del_entry(&pt->link);
 			queue_request(engine, pt, prio);
 		}
-		submit_queue(engine, prio);
+
+		if (prio > engine->execlists.queue_priority &&
+		    i915_sw_fence_done(&pt_to_request(pt)->submit))
+			__submit_queue(engine, prio);
 	}
 
 	spin_unlock_irq(&engine->timeline->lock);