[Intel-gfx] [PATCH 2/3] drm/i915/gem: Treat submit-fence as weak dependency for new clients

[Chris Wilson]

The submit-fence adds a weak dependency to the requests, and for the
purpose of our FQ_CODEL hinting we do not want to treat as a
restriction. This is primarily because clients may treat submit-fences
as a bidirectional bonding between a pair of co-ordinating requests.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
index 966523a8503f..e8bf0cf02fd7 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_execbuffer.c
@@ -2565,6 +2565,17 @@ static void retire_requests(struct intel_timeline *tl, struct i915_request *end)
 			break;
 }
 
+static bool new_client(struct i915_request *rq)
+{
+	struct i915_dependency *p;
+
+	list_for_each_entry(p, &rq->sched.signalers_list, signal_link)
+		if (!(p->flags & I915_DEPENDENCY_WEAK))
+			return false;
+
+	return true;
+}
+
 static void eb_request_add(struct i915_execbuffer *eb)
 {
 	struct i915_request *rq = eb->request;
@@ -2604,7 +2615,7 @@ static void eb_request_add(struct i915_execbuffer *eb)
 		 * Allow interactive/synchronous clients to jump ahead of
 		 * the bulk clients. (FQ_CODEL)
 		 */
-		if (list_empty(&rq->sched.signalers_list))
+		if (new_client(rq))
 			attr.priority |= I915_PRIORITY_WAIT;
 	} else {
 		/* Serialise with context_close via the add_to_timeline */
-- 
2.20.1