sync: optimize fence merges
[linux-2.6.git] / drivers / base / sync.c
index fa2f407..13b26d2 100644 (file)
@@ -312,6 +312,55 @@ static int sync_fence_copy_pts(struct sync_fence *dst, struct sync_fence *src)
        return 0;
 }
 
+static int sync_fence_merge_pts(struct sync_fence *dst, struct sync_fence *src)
+{
+       struct list_head *src_pos, *dst_pos, *n;
+
+       list_for_each(src_pos, &src->pt_list_head) {
+               struct sync_pt *src_pt =
+                       container_of(src_pos, struct sync_pt, pt_list);
+               bool collapsed = false;
+
+               list_for_each_safe(dst_pos, n, &dst->pt_list_head) {
+                       struct sync_pt *dst_pt =
+                               container_of(dst_pos, struct sync_pt, pt_list);
+                       /* collapse two sync_pts on the same timeline
+                        * to a single sync_pt that will signal at
+                        * the later of the two
+                        */
+                       if (dst_pt->parent == src_pt->parent) {
+                               if (dst_pt->parent->ops->compare(dst_pt, src_pt) == -1) {
+                                       struct sync_pt *new_pt =
+                                               sync_pt_dup(src_pt);
+                                       if (new_pt == NULL)
+                                               return -ENOMEM;
+
+                                       new_pt->fence = dst;
+                                       list_replace(&dst_pt->pt_list,
+                                                    &new_pt->pt_list);
+                                       sync_pt_activate(new_pt);
+                                       sync_pt_free(dst_pt);
+                               }
+                               collapsed = true;
+                               break;
+                       }
+               }
+
+               if (!collapsed) {
+                       struct sync_pt *new_pt = sync_pt_dup(src_pt);
+
+                       if (new_pt == NULL)
+                               return -ENOMEM;
+
+                       new_pt->fence = dst;
+                       list_add(&new_pt->pt_list, &dst->pt_list_head);
+                       sync_pt_activate(new_pt);
+               }
+       }
+
+       return 0;
+}
+
 static void sync_fence_free_pts(struct sync_fence *fence)
 {
        struct list_head *pos, *n;
@@ -386,7 +435,7 @@ struct sync_fence *sync_fence_merge(const char *name,
        if (err < 0)
                goto err;
 
-       err = sync_fence_copy_pts(fence, b);
+       err = sync_fence_merge_pts(fence, b);
        if (err < 0)
                goto err;