Commit 7c572e1b authored May 03, 2018 by Chris Wilson

drm/i915: Keep one request in our ring_list

Don't pre-emptively retire the oldest request in our ring's list if it
is the only request. We keep various bits of state alive using the
active reference from the request and would rather transfer that state
over to a new request rather than the more involved process of retiring
and reacquiring it.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180503195115.22309-2-chris@chris-wilson.co.uk

parent 3365e226

drivers/gpu/drm/i915/i915_request.c

+3 −3

Original line number	Diff line number	Diff line
		@@ -695,9 +695,9 @@ i915_request_alloc(struct intel_engine_cs engine, struct i915_gem_context ctx)
		goto err_unreserve;

		/* Move our oldest request to the slab-cache (if not in use!) */
		rq = list_first_entry_or_null(&ring->request_list,
		typeof(*rq), ring_link);
		if (rq && i915_request_completed(rq))
		rq = list_first_entry(&ring->request_list, typeof(*rq), ring_link);
		if (!list_is_last(&rq->ring_link, &ring->request_list) &&
		i915_request_completed(rq))
		i915_request_retire(rq);

		/*