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FAILED: patch "[PATCH] drm/i915/execlists: Enable timeslice on partial virtual" failed to apply to 5.4-stable tree

PATCH [email protected] 1 participant 1 message Mar 16, 2020

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Stable branch DRM drivers Intel i915
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The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From eafc2aa20fba319b6e791a1b0c45a91511eccb6b Mon Sep 17 00:00:00 2001
From: Chris Wilson <[email protected]>
Date: Fri, 6 Mar 2020 11:30:10 +0000
Subject: [PATCH] drm/i915/execlists: Enable timeslice on partial virtual
engine dequeue

If we stop filling the ELSP due to an incompatible virtual engine request, check if we should enable the timeslice on behalf of the queue.

This fixes the case where we are inspecting the last->next element when we know that the last element is the last request in the execution queue, and so decided we did not need to enable timeslicing despite the intent to do so!

Fixes 8ee36e048c98 ("drm/i915/execlists: Minimalistic timeslicing")
Signed-off-by Chris Wilson <[email protected]>
Cc Mika Kuoppala <[email protected]>
Cc Tvrtko Ursulin <[email protected]>
Cc <[email protected]> # v5.4+
Reviewed-by Mika Kuoppala <[email protected]>
Link https://patchwork.freedesktop.org/patch/msgid/[email protected]
(cherry picked from commit 3df2deed411e0f1b7312baf0139aab8bba4c0410)
Signed-off-by Jani Nikula <[email protected]>
drivers/gpu/drm/i915/gt/intel_lrc.c +18 -11
index fe8a59aaa629..940e7f7df69a 100644
@@ -1679,11 +1679,9 @@ need_timeslice(struct intel_engine_cs *engine, const struct i915_request *rq)
 	if (!intel_engine_has_timeslices(engine))
 		return false;
 
-	if (list_is_last(&rq->sched.link, &engine->active.requests))
-		return false;
-
-	hint = max(rq_prio(list_next_entry(rq, sched.link)),
-		   engine->execlists.queue_priority_hint);
+	hint = engine->execlists.queue_priority_hint;
+	if (!list_is_last(&rq->sched.link, &engine->active.requests))
+		hint = max(hint, rq_prio(list_next_entry(rq, sched.link)));
 
 	return hint >= effective_prio(rq);
 }

@@ -1725,6 +1723,18 @@ static void set_timeslice(struct intel_engine_cs *engine)
 	set_timer_ms(&engine->execlists.timer, active_timeslice(engine));
 }
 
+static void start_timeslice(struct intel_engine_cs *engine)
+{
+	struct intel_engine_execlists *execlists = &engine->execlists;
+
+	execlists->switch_priority_hint = execlists->queue_priority_hint;
+
+	if (timer_pending(&execlists->timer))
+		return;
+
+	set_timer_ms(&execlists->timer, timeslice(engine));
+}
+
 static void record_preemption(struct intel_engine_execlists *execlists)
 {
 	(void)I915_SELFTEST_ONLY(execlists->preempt_hang.count++);

@@ -1888,11 +1898,7 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 				 * Even if ELSP[1] is occupied and not worthy
 				 * of timeslices, our queue might be.
 				 */
-				if (!execlists->timer.expires &&
-				    need_timeslice(engine, last))
-					set_timer_ms(&execlists->timer,
-						     timeslice(engine));
-
+				start_timeslice(engine);
 				return;
 			}
 		}

@@ -1927,7 +1933,8 @@ static void execlists_dequeue(struct intel_engine_cs *engine)
 
 			if (last && !can_merge_rq(last, rq)) {
 				spin_unlock(&ve->base.active.lock);
-				return; /* leave this for another */
+				start_timeslice(engine);
+				return; /* leave this for another sibling */
 			}
 
 			ENGINE_TRACE(engine,