diff mbox series

[34/66] drm/i915/gt: Decouple completed requests on unwind

Message ID 20200715115147.11866-34-chris@chris-wilson.co.uk (mailing list archive)
State New, archived
Headers show
Series [01/66] drm/i915: Reduce i915_request.lock contention for i915_request_wait | expand

Commit Message

Chris Wilson July 15, 2020, 11:51 a.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>
---
 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 aa7be7f05f8c..f52b52a7b1d3 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -1114,8 +1114,10 @@  __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 83696955ddf7..31c60e6c5c7a 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -311,7 +311,8 @@  bool i915_request_retire(struct i915_request *rq)
 	 * request that we have removed from the HW and put back on a run
 	 * queue.
 	 */
-	remove_from_engine(rq);
+	if (!list_empty(&rq->sched.link))
+		remove_from_engine(rq);
 
 	spin_lock_irq(&rq->lock);
 	if (!i915_request_signaled(rq))