diff mbox series

[CI,1/5] drm/i915/gt: Decouple completed requests on unwind

Message ID 20201126140407.31952-1-chris@chris-wilson.co.uk (mailing list archive)
State New, archived
Headers show
Series [CI,1/5] drm/i915/gt: Decouple completed requests on unwind | expand

Commit Message

Chris Wilson Nov. 26, 2020, 2:04 p.m. UTC 
Since the introduction of preempt-to-busy, requests can complete in the
background, even while they are not on the engine->active.requests list.
As such, the engine->active.request list itself is not in strict
retirement order, and we have to scan the entire list while unwinding to
not miss any. However, if the request is completed we currently leave it
on the list [until retirement], but we could just as simply remove it
and stop treating it as active. We would only have to then traverse it
once while unwinding in quick succession.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 6 ++++--
 drivers/gpu/drm/i915/i915_request.c | 3 ++-
 2 files changed, 6 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 30aa59fb7271..cf11cbac241b 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1116,8 +1116,10 @@  __unwind_incomplete_requests(struct intel_engine_cs *engine)
 	list_for_each_entry_safe_reverse(rq, rn,
 					 &engine->active.requests,
 					 sched.link) {
-		if (i915_request_completed(rq))
-			continue; /* XXX */
+		if (i915_request_completed(rq)) {
+			list_del_init(&rq->sched.link);
+			continue;
+		}
 
 		__i915_request_unsubmit(rq);
 
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 8d7d29c9e375..a9db1376b996 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -321,7 +321,8 @@  bool i915_request_retire(struct i915_request *rq)
 	 * after removing the breadcrumb and signaling it, so that we do not
 	 * inadvertently attach the breadcrumb to a completed request.
 	 */
-	remove_from_engine(rq);
+	if (!list_empty(&rq->sched.link))
+		remove_from_engine(rq);
 	GEM_BUG_ON(!llist_empty(&rq->execute_cb));
 
 	__list_del_entry(&rq->link); /* poison neither prev/next (RCU walks) */