drm/ttm: Improved fencing of buffer object lists

Drastically reduce the number of spin lock / unlock operations by performing
unreserving and fencing under global locks.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Jerome Glisse <j.glisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 12 insertions, 0 deletions

diff --git a/include/drm/ttm/ttm_bo_driver.h b/include/drm/ttm/ttm_bo_driver.h
index ca8131e98300..cfb9ca4ec1c4 100644
--- a/include/drm/ttm/ttm_bo_driver.h
+++ b/include/drm/ttm/ttm_bo_driver.h
@@ -910,6 +910,16 @@ extern int ttm_bo_reserve_locked(struct ttm_buffer_object *bo,
 extern void ttm_bo_unreserve(struct ttm_buffer_object *bo);
 
 /**
+ * ttm_bo_unreserve_locked
+ *
+ * @bo: A pointer to a struct ttm_buffer_object.
+ *
+ * Unreserve a previous reservation of @bo.
+ * Needs to be called with struct ttm_bo_global::lru_lock held.
+ */
+extern void ttm_bo_unreserve_locked(struct ttm_buffer_object *bo);
+
+/**
  * ttm_bo_wait_unreserved
  *
  * @bo: A pointer to a struct ttm_buffer_object.
diff --git a/include/drm/ttm/ttm_execbuf_util.h b/include/drm/ttm/ttm_execbuf_util.h
index fd09b8438977..535ab00407e0 100644
--- a/include/drm/ttm/ttm_execbuf_util.h
+++ b/include/drm/ttm/ttm_execbuf_util.h
@@ -44,6 +44,7 @@
  * @reserved:       Indicates whether @bo has been reserved for validation.
  * @removed:        Indicates whether @bo has been removed from lru lists.
  * @put_count:      Number of outstanding references on bo::list_kref.
+ * @old_sync_obj:   Pointer to a sync object about to be unreferenced
  */
 
 struct ttm_validate_buffer {
@@ -53,6 +54,7 @@ struct ttm_validate_buffer {
         bool reserved;
         bool removed;
         int put_count;
+        void *old_sync_obj;
 };
 
 /**