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* [Intel-gfx] [PATCH] drm/i915/gt: Prevent queuing retire workers on the virtual engine
@ 2020-02-06 15:23 Chris Wilson
  2020-02-06 15:29 ` Chris Wilson
                   ` (5 more replies)
  0 siblings, 6 replies; 13+ messages in thread
From: Chris Wilson @ 2020-02-06 15:23 UTC (permalink / raw)
  To: intel-gfx

Virtual engines are fleeting. They carry a reference count and may be freed
when their last request is retired. This makes them unsuitable for the
task of housing engine->retire.work so assert that it is not used.

Tvrtko tracked down an instance where we did indeed violate this rule.
In virtal_submit_request, we flush a completed request directly with
__i915_request_submit and this causes us to queue that request on the
veng's breadcrumb list and signal it. Leading us down a path where we
should not attach the retire.

Reported-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Fixes: dc93c9b69315 ("drm/i915/gt: Schedule request retirement when signaler idles")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/gt/intel_breadcrumbs.c | 3 +++
 drivers/gpu/drm/i915/gt/intel_gt_requests.c | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
index 0ba524a414c6..cbad7fe722ce 100644
--- a/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
+++ b/drivers/gpu/drm/i915/gt/intel_breadcrumbs.c
@@ -136,6 +136,9 @@ static void add_retire(struct intel_breadcrumbs *b, struct intel_timeline *tl)
 	struct intel_engine_cs *engine =
 		container_of(b, struct intel_engine_cs, breadcrumbs);
 
+	if (unlikely(intel_engine_is_virtual(engine)))
+		engine = intel_virtual_engine_get_sibling(engine, 0);
+
 	intel_engine_add_retire(engine, tl);
 }
 
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_requests.c b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
index 7ef1d37970f6..8a5054f21bf8 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_requests.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_requests.c
@@ -99,6 +99,9 @@ static bool add_retire(struct intel_engine_cs *engine,
 void intel_engine_add_retire(struct intel_engine_cs *engine,
 			     struct intel_timeline *tl)
 {
+	/* We don't deal well with the engine disappearing beneath us */
+	GEM_BUG_ON(intel_engine_is_virtual(engine));
+
 	if (add_retire(engine, tl))
 		schedule_work(&engine->retire_work);
 }
-- 
2.25.0

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^ permalink raw reply related	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2020-02-09 10:44 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-02-06 15:23 [Intel-gfx] [PATCH] drm/i915/gt: Prevent queuing retire workers on the virtual engine Chris Wilson
2020-02-06 15:29 ` Chris Wilson
2020-02-06 15:57   ` Tvrtko Ursulin
2020-02-06 15:44 ` Mika Kuoppala
2020-02-06 16:12 ` [Intel-gfx] [PATCH v2] " Chris Wilson
2020-02-06 16:23   ` Chris Wilson
2020-02-06 16:32     ` [Intel-gfx] [PATCH] " Chris Wilson
2020-02-06 16:40       ` Chris Wilson
2020-02-06 16:44       ` Tvrtko Ursulin
2020-02-06 16:48         ` Chris Wilson
2020-02-06 16:41 ` [Intel-gfx] [PATCH v1] " Chris Wilson
2020-02-06 17:08 ` [Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915/gt: Prevent queuing retire workers on the virtual engine (rev4) Patchwork
2020-02-09 10:44 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork

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