[Intel-gfx] [PATCH] drm/i915/guc: Fix a false alert of memory leak when free LRC

[yu.dai at intel.com]

From: Alex Dai <yu.dai at intel.com>

There is a memory leak warning message from i915_gem_context_clean
when GuC submission is enabled. The reason is that the request (so
the LRC associated with it) is freed early than moving the vma list
to inactive. When retire a gem object, this patch moves its vma
list to inactive first to avoid the false alert of memory leak.

We are not seeing this in ExecList (non-GuC) mode because the gem
request is moved to execlist_retired_req_list queue. The management
of this queue, therefore free of LRC, happens after retire of vma
list (i915_gem_retire_requests_ring).

Signed-off-by: Alex Dai <yu.dai at intel.com>
---
 drivers/gpu/drm/i915/i915_gem.c | 29 ++++++++++++++++-------------
 1 file changed, 16 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7d6b0c8..a903d45 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -2377,28 +2377,31 @@ i915_gem_object_retire__read(struct drm_i915_gem_object *obj, int ring)
 	RQ_BUG_ON(obj->last_read_req[ring] == NULL);
 	RQ_BUG_ON(!(obj->active & (1 << ring)));
 
+	obj->active &= ~(1 << ring);
+	if (!obj->active) {
+		/* Bump our place on the bound list to keep it roughly in LRU
+		 * order so that we don't steal from recently used but inactive
+		 * objects (unless we are forced to ofc!)
+		 */
+		list_move_tail(&obj->global_list,
+				&to_i915(obj->base.dev)->mm.bound_list);
+
+		list_for_each_entry(vma, &obj->vma_list, vma_link) {
+			if (!list_empty(&vma->mm_list))
+				list_move_tail(&vma->mm_list,
+						&vma->vm->inactive_list);
+		}
+	}
+
 	list_del_init(&obj->ring_list[ring]);
 	i915_gem_request_assign(&obj->last_read_req[ring], NULL);
 
 	if (obj->last_write_req && obj->last_write_req->ring->id == ring)
 		i915_gem_object_retire__write(obj);
 
-	obj->active &= ~(1 << ring);
 	if (obj->active)
 		return;
 
-	/* Bump our place on the bound list to keep it roughly in LRU order
-	 * so that we don't steal from recently used but inactive objects
-	 * (unless we are forced to ofc!)
-	 */
-	list_move_tail(&obj->global_list,
-		       &to_i915(obj->base.dev)->mm.bound_list);
-
-	list_for_each_entry(vma, &obj->vma_list, vma_link) {
-		if (!list_empty(&vma->mm_list))
-			list_move_tail(&vma->mm_list, &vma->vm->inactive_list);
-	}
-
 	i915_gem_request_assign(&obj->last_fenced_req, NULL);
 	drm_gem_object_unreference(&obj->base);
 }
-- 
1.9.1