[PATCH] drm/i915/execlists: Simply walk back along request timeline on reset

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



The request's timeline will only contain requests from this context, in
order of execution. Therefore, we can simply look back along this
timeline to find the currently executing request.

If we do find that the current context has completed its last request,
that does not imply that all requests are completed in the context, so
only advance the ring->head up to the end of the known completions!

Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/i915/gt/intel_lrc.c | 31 +++++++++++------------------
 1 file changed, 12 insertions(+), 19 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c
index 16340740139d..c9ee0408479c 100644
--- a/drivers/gpu/drm/i915/gt/intel_lrc.c
+++ b/drivers/gpu/drm/i915/gt/intel_lrc.c
@@ -252,27 +252,18 @@ static void mark_eio(struct i915_request *rq)
 
 static struct i915_request *active_request(struct i915_request *rq)
 {
-	const struct intel_context * const ce = rq->hw_context;
-	struct i915_request *active = NULL;
 	struct list_head *list;
 
-	if (!i915_request_is_active(rq)) /* unwound, but incomplete! */
-		return rq;
-
 	rcu_read_lock();
 	list = &rcu_dereference(rq->timeline)->requests;
 	list_for_each_entry_from_reverse(rq, list, link) {
 		if (i915_request_completed(rq))
 			break;
-
-		if (rq->hw_context != ce)
-			break;
-
-		active = rq;
 	}
 	rcu_read_unlock();
 
-	return active;
+	GEM_BUG_ON(i915_request_completed(rq));
+	return rq;
 }
 
 static inline u32 intel_hws_preempt_address(struct intel_engine_cs *engine)
@@ -1073,6 +1064,7 @@ static void reset_active(struct i915_request *rq,
 			 struct intel_engine_cs *engine)
 {
 	struct intel_context * const ce = rq->hw_context;
+	u32 head;
 
 	/*
 	 * The executing context has been cancelled. We want to prevent
@@ -1093,11 +1085,11 @@ static void reset_active(struct i915_request *rq,
 		  __func__, engine->name, rq->fence.context, rq->fence.seqno);
 
 	/* On resubmission of the active request, payload will be scrubbed */
-	rq = active_request(rq);
-	if (rq)
-		ce->ring->head = intel_ring_wrap(ce->ring, rq->head);
+	if (i915_request_completed(rq))
+		head = rq->tail;
 	else
-		ce->ring->head = ce->ring->tail;
+		head = active_request(rq)->head;
+	ce->ring->head = intel_ring_wrap(ce->ring, head);
 	intel_ring_update_space(ce->ring);
 
 	/* Scrub the context image to prevent replaying the previous batch */
@@ -2990,16 +2982,17 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
 	ce = rq->hw_context;
 	GEM_BUG_ON(!i915_vma_is_pinned(ce->state));
 
-	rq = active_request(rq);
-	if (!rq) {
+	if (i915_request_completed(rq)) {
 		/* Idle context; tidy up the ring so we can restart afresh */
-		ce->ring->head = ce->ring->tail;
+		ce->ring->head = intel_ring_wrap(ce->ring, rq->tail);
 		goto out_replay;
 	}
 
 	/* Context has requests still in-flight; it should not be idle! */
 	GEM_BUG_ON(i915_active_is_idle(&ce->active));
+	rq = active_request(rq);
 	ce->ring->head = intel_ring_wrap(ce->ring, rq->head);
+	GEM_BUG_ON(ce->ring->head == ce->ring->tail);
 
 	/*
 	 * If this request hasn't started yet, e.g. it is waiting on a
@@ -3043,7 +3036,7 @@ static void __execlists_reset(struct intel_engine_cs *engine, bool stalled)
 	restore_default_state(ce, engine);
 
 out_replay:
-	GEM_TRACE("%s replay {head:%04x, tail:%04x\n",
+	GEM_TRACE("%s replay {head:%04x, tail:%04x}\n",
 		  engine->name, ce->ring->head, ce->ring->tail);
 	intel_ring_update_space(ce->ring);
 	__execlists_reset_reg_state(ce, engine);
-- 
2.24.0.rc1

_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx




[Index of Archives]     [AMD Graphics]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux