[Intel-gfx] [PATCH 08/64] drm/i915: Retire oldest completed request before allocating next

[Chris Wilson]

In order to keep the memory allocated for requests reasonably tight, try
to reuse the oldest request (so long as it is completed and has no
external references) for the next allocation.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/i915_gem_request.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem_request.c b/drivers/gpu/drm/i915/i915_gem_request.c
index 9e9aa6b725f7..ee1189c35509 100644
--- a/drivers/gpu/drm/i915/i915_gem_request.c
+++ b/drivers/gpu/drm/i915/i915_gem_request.c
@@ -226,6 +226,13 @@ __i915_gem_request_alloc(struct intel_engine_cs *engine,
 	if (ret)
 		return ret;
 
+	if (!list_empty(&engine->request_list)) {
+		req = list_first_entry(&engine->request_list,
+				       typeof(*req), list);
+		if (i915_gem_request_completed(req))
+			i915_gem_request_retire(req);
+	}
+
 	req = kmem_cache_zalloc(dev_priv->requests, GFP_KERNEL);
 	if (!req)
 		return -ENOMEM;
-- 
2.8.1