[Intel-gfx] [PATCH 13/41] drm/i915: Extract request suspension from the execlists

[Chris Wilson <chris@chris-wilson.co.uk>]

Make the ability to suspend and resume a request and its dependents
generic.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 .../drm/i915/gt/intel_execlists_submission.c  | 167 +-----------------
 drivers/gpu/drm/i915/gt/selftest_execlists.c  |   8 +-
 drivers/gpu/drm/i915/i915_scheduler.c         | 153 ++++++++++++++++
 drivers/gpu/drm/i915/i915_scheduler.h         |  10 ++
 4 files changed, 169 insertions(+), 169 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
index f7d383dd5144..f2967c31dd70 100644
--- a/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
+++ b/drivers/gpu/drm/i915/gt/intel_execlists_submission.c
@@ -1922,169 +1922,6 @@ static void post_process_csb(struct i915_request **port,
 		execlists_schedule_out(*port++);
 }
 
-static void __execlists_hold(struct i915_request *rq)
-{
-	LIST_HEAD(list);
-
-	do {
-		struct i915_dependency *p;
-
-		if (i915_request_is_active(rq))
-			__i915_request_unsubmit(rq);
-
-		clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
-		list_move_tail(&rq->sched.link, &rq->engine->active.hold);
-		i915_request_set_hold(rq);
-		RQ_TRACE(rq, "on hold\n");
-
-		for_each_waiter(p, rq) {
-			struct i915_request *w =
-				container_of(p->waiter, typeof(*w), sched);
-
-			if (p->flags & I915_DEPENDENCY_WEAK)
-				continue;
-
-			/* Leave semaphores spinning on the other engines */
-			if (w->engine != rq->engine)
-				continue;
-
-			if (!i915_request_is_ready(w))
-				continue;
-
-			if (__i915_request_is_complete(w))
-				continue;
-
-			if (i915_request_on_hold(w))
-				continue;
-
-			list_move_tail(&w->sched.link, &list);
-		}
-
-		rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
-	} while (rq);
-}
-
-static bool execlists_hold(struct intel_engine_cs *engine,
-			   struct i915_request *rq)
-{
-	if (i915_request_on_hold(rq))
-		return false;
-
-	spin_lock_irq(&engine->active.lock);
-
-	if (__i915_request_is_complete(rq)) { /* too late! */
-		rq = NULL;
-		goto unlock;
-	}
-
-	/*
-	 * Transfer this request onto the hold queue to prevent it
-	 * being resumbitted to HW (and potentially completed) before we have
-	 * released it. Since we may have already submitted following
-	 * requests, we need to remove those as well.
-	 */
-	GEM_BUG_ON(i915_request_on_hold(rq));
-	GEM_BUG_ON(rq->engine != engine);
-	__execlists_hold(rq);
-	GEM_BUG_ON(list_empty(&engine->active.hold));
-
-unlock:
-	spin_unlock_irq(&engine->active.lock);
-	return rq;
-}
-
-static bool hold_request(const struct i915_request *rq)
-{
-	struct i915_dependency *p;
-	bool result = false;
-
-	/*
-	 * If one of our ancestors is on hold, we must also be on hold,
-	 * otherwise we will bypass it and execute before it.
-	 */
-	rcu_read_lock();
-	for_each_signaler(p, rq) {
-		const struct i915_request *s =
-			container_of(p->signaler, typeof(*s), sched);
-
-		if (s->engine != rq->engine)
-			continue;
-
-		result = i915_request_on_hold(s);
-		if (result)
-			break;
-	}
-	rcu_read_unlock();
-
-	return result;
-}
-
-static void __execlists_unhold(struct i915_request *rq)
-{
-	LIST_HEAD(list);
-
-	do {
-		struct i915_dependency *p;
-
-		RQ_TRACE(rq, "hold release\n");
-
-		GEM_BUG_ON(!i915_request_on_hold(rq));
-		GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit));
-
-		i915_request_clear_hold(rq);
-		list_move_tail(&rq->sched.link,
-			       i915_sched_lookup_priolist(rq->engine,
-							  rq_prio(rq)));
-		set_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
-
-		/* Also release any children on this engine that are ready */
-		for_each_waiter(p, rq) {
-			struct i915_request *w =
-				container_of(p->waiter, typeof(*w), sched);
-
-			if (p->flags & I915_DEPENDENCY_WEAK)
-				continue;
-
-			/* Propagate any change in error status */
-			if (rq->fence.error)
-				i915_request_set_error_once(w, rq->fence.error);
-
-			if (w->engine != rq->engine)
-				continue;
-
-			if (!i915_request_on_hold(w))
-				continue;
-
-			/* Check that no other parents are also on hold */
-			if (hold_request(w))
-				continue;
-
-			list_move_tail(&w->sched.link, &list);
-		}
-
-		rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
-	} while (rq);
-}
-
-static void execlists_unhold(struct intel_engine_cs *engine,
-			     struct i915_request *rq)
-{
-	spin_lock_irq(&engine->active.lock);
-
-	/*
-	 * Move this request back to the priority queue, and all of its
-	 * children and grandchildren that were suspended along with it.
-	 */
-	__execlists_unhold(rq);
-
-	if (rq_prio(rq) > engine->execlists.queue_priority_hint) {
-		engine->execlists.queue_priority_hint = rq_prio(rq);
-		tasklet_hi_schedule(&engine->execlists.tasklet);
-	}
-
-	spin_unlock_irq(&engine->active.lock);
-}
-
 struct execlists_capture {
 	struct work_struct work;
 	struct i915_request *rq;
@@ -2117,7 +1954,7 @@ static void execlists_capture_work(struct work_struct *work)
 	i915_gpu_coredump_put(cap->error);
 
 	/* Return this request and all that depend upon it for signaling */
-	execlists_unhold(engine, cap->rq);
+	intel_engine_resume_request(engine, cap->rq);
 	i915_request_put(cap->rq);
 
 	kfree(cap);
@@ -2242,7 +2079,7 @@ static void execlists_capture(struct intel_engine_cs *engine)
 	 * simply hold that request accountable for being non-preemptible
 	 * long enough to force the reset.
 	 */
-	if (!execlists_hold(engine, cap->rq))
+	if (!intel_engine_suspend_request(engine, cap->rq))
 		goto err_rq;
 
 	INIT_WORK(&cap->work, execlists_capture_work);
diff --git a/drivers/gpu/drm/i915/gt/selftest_execlists.c b/drivers/gpu/drm/i915/gt/selftest_execlists.c
index 84017eb9dd8b..e34858b111c8 100644
--- a/drivers/gpu/drm/i915/gt/selftest_execlists.c
+++ b/drivers/gpu/drm/i915/gt/selftest_execlists.c
@@ -608,7 +608,7 @@ static int live_hold_reset(void *arg)
 		GEM_BUG_ON(execlists_active(&engine->execlists) != rq);
 
 		i915_request_get(rq);
-		execlists_hold(engine, rq);
+		intel_engine_suspend_request(engine, rq);
 		GEM_BUG_ON(!i915_request_on_hold(rq));
 
 		__intel_engine_reset_bh(engine, NULL);
@@ -630,7 +630,7 @@ static int live_hold_reset(void *arg)
 		GEM_BUG_ON(!i915_request_on_hold(rq));
 
 		/* But is resubmitted on release */
-		execlists_unhold(engine, rq);
+		intel_engine_resume_request(engine, rq);
 		if (i915_request_wait(rq, 0, HZ / 5) < 0) {
 			pr_err("%s: held request did not complete!\n",
 			       engine->name);
@@ -4587,7 +4587,7 @@ static int reset_virtual_engine(struct intel_gt *gt,
 	GEM_BUG_ON(rq->engine != engine);
 
 	/* Reset the engine while keeping our active request on hold */
-	execlists_hold(engine, rq);
+	intel_engine_suspend_request(engine, rq);
 	GEM_BUG_ON(!i915_request_on_hold(rq));
 
 	__intel_engine_reset_bh(engine, NULL);
@@ -4610,7 +4610,7 @@ static int reset_virtual_engine(struct intel_gt *gt,
 	GEM_BUG_ON(!i915_request_on_hold(rq));
 
 	/* But is resubmitted on release */
-	execlists_unhold(engine, rq);
+	intel_engine_resume_request(engine, rq);
 	if (i915_request_wait(rq, 0, HZ / 5) < 0) {
 		pr_err("%s: held request did not complete!\n",
 		       engine->name);
diff --git a/drivers/gpu/drm/i915/i915_scheduler.c b/drivers/gpu/drm/i915/i915_scheduler.c
index bd687c891ab6..1f8c647d59d6 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.c
+++ b/drivers/gpu/drm/i915/i915_scheduler.c
@@ -574,6 +574,159 @@ __intel_engine_rewind_requests(struct intel_engine_cs *engine)
 	return active;
 }
 
+bool __intel_engine_suspend_request(struct intel_engine_cs *engine,
+				    struct i915_request *rq)
+{
+	LIST_HEAD(list);
+
+	lockdep_assert_held(&engine->active.lock);
+	GEM_BUG_ON(rq->engine != engine);
+
+	if (__i915_request_is_complete(rq)) /* too late! */
+		return false;
+
+	if (i915_request_on_hold(rq))
+		return false;
+
+	ENGINE_TRACE(engine, "suspending request %llx:%lld\n",
+		     rq->fence.context, rq->fence.seqno);
+
+	/*
+	 * Transfer this request onto the hold queue to prevent it
+	 * being resumbitted to HW (and potentially completed) before we have
+	 * released it. Since we may have already submitted following
+	 * requests, we need to remove those as well.
+	 */
+	do {
+		struct i915_dependency *p;
+
+		if (i915_request_is_active(rq))
+			__i915_request_unsubmit(rq);
+
+		clear_bit(I915_FENCE_FLAG_PQUEUE, &rq->fence.flags);
+		list_move_tail(&rq->sched.link, &rq->engine->active.hold);
+		i915_request_set_hold(rq);
+		RQ_TRACE(rq, "on hold\n");
+
+		for_each_waiter(p, rq) {
+			struct i915_request *w =
+				container_of(p->waiter, typeof(*w), sched);
+
+			if (p->flags & I915_DEPENDENCY_WEAK)
+				continue;
+
+			/* Leave semaphores spinning on the other engines */
+			if (w->engine != engine)
+				continue;
+
+			if (!i915_request_is_ready(w))
+				continue;
+
+			if (__i915_request_is_complete(w))
+				continue;
+
+			if (i915_request_on_hold(w)) /* acts as a visited bit */
+				continue;
+
+			list_move_tail(&w->sched.link, &list);
+		}
+
+		rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
+	} while (rq);
+
+	GEM_BUG_ON(list_empty(&engine->active.hold));
+
+	return true;
+}
+
+bool intel_engine_suspend_request(struct intel_engine_cs *engine,
+				  struct i915_request *rq)
+{
+	bool result;
+
+	if (i915_request_on_hold(rq))
+		return false;
+
+	spin_lock_irq(&engine->active.lock);
+	result = __intel_engine_suspend_request(engine, rq);
+	spin_unlock_irq(&engine->active.lock);
+
+	return result;
+}
+
+void __intel_engine_resume_request(struct intel_engine_cs *engine,
+				   struct i915_request *rq)
+{
+	LIST_HEAD(list);
+
+	lockdep_assert_held(&engine->active.lock);
+
+	if (rq_prio(rq) > engine->execlists.queue_priority_hint) {
+		engine->execlists.queue_priority_hint = rq_prio(rq);
+		tasklet_hi_schedule(&engine->execlists.tasklet);
+	}
+
+	if (!i915_request_on_hold(rq))
+		return;
+
+	ENGINE_TRACE(engine, "resuming request %llx:%lld\n",
+		     rq->fence.context, rq->fence.seqno);
+
+	/*
+	 * Move this request back to the priority queue, and all of its
+	 * children and grandchildren that were suspended along with it.
+	 */
+	do {
+		struct i915_dependency *p;
+
+		RQ_TRACE(rq, "hold release\n");
+
+		GEM_BUG_ON(!i915_request_on_hold(rq));
+		GEM_BUG_ON(!i915_sw_fence_signaled(&rq->submit));
+
+		i915_request_clear_hold(rq);
+		list_del_init(&rq->sched.link);
+
+		queue_request(engine, rq);
+
+		/* Also release any children on this engine that are ready */
+		for_each_waiter(p, rq) {
+			struct i915_request *w =
+				container_of(p->waiter, typeof(*w), sched);
+
+			if (p->flags & I915_DEPENDENCY_WEAK)
+				continue;
+
+			/* Propagate any change in error status */
+			if (rq->fence.error)
+				i915_request_set_error_once(w, rq->fence.error);
+
+			if (w->engine != engine)
+				continue;
+
+			/* We also treat the on-hold status as a visited bit */
+			if (!i915_request_on_hold(w))
+				continue;
+
+			/* Check that no other parents are also on hold [BFS] */
+			if (hold_request(w))
+				continue;
+
+			list_move_tail(&w->sched.link, &list);
+		}
+
+		rq = list_first_entry_or_null(&list, typeof(*rq), sched.link);
+	} while (rq);
+}
+
+void intel_engine_resume_request(struct intel_engine_cs *engine,
+				 struct i915_request *rq)
+{
+	spin_lock_irq(&engine->active.lock);
+	__intel_engine_resume_request(engine, rq);
+	spin_unlock_irq(&engine->active.lock);
+}
+
 void i915_sched_node_init(struct i915_sched_node *node)
 {
 	spin_lock_init(&node->lock);
diff --git a/drivers/gpu/drm/i915/i915_scheduler.h b/drivers/gpu/drm/i915/i915_scheduler.h
index 50fdc7168d38..421254cb8e8c 100644
--- a/drivers/gpu/drm/i915/i915_scheduler.h
+++ b/drivers/gpu/drm/i915/i915_scheduler.h
@@ -44,6 +44,16 @@ void i915_request_enqueue(struct i915_request *request);
 struct i915_request *
 __intel_engine_rewind_requests(struct intel_engine_cs *engine);
 
+bool __intel_engine_suspend_request(struct intel_engine_cs *engine,
+				    struct i915_request *rq);
+void __intel_engine_resume_request(struct intel_engine_cs *engine,
+				   struct i915_request *request);
+
+bool intel_engine_suspend_request(struct intel_engine_cs *engine,
+				  struct i915_request *request);
+void intel_engine_resume_request(struct intel_engine_cs *engine,
+				 struct i915_request *rq);
+
 struct list_head *
 i915_sched_lookup_priolist(struct intel_engine_cs *engine, int prio);
 
-- 
2.20.1

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