Save reiterating over unreachables

Author: markshannon

Modules/gcmodule.c

@@ -1125,13 +1125,15 @@ finalize_garbage(PyThreadState *tstate, PyGC_Head *collectable)
  * tricky business as the lists can be changing and we don't know which
  * objects may be freed.  It is possible I screwed something up here.
  */
-static void
+static uintptr_t
 delete_garbage(PyThreadState *tstate, GCState *gcstate,
                PyGC_Head *collectable, PyGC_Head *old)
 {
+    uintptr_t deleted = 0;
     assert(!_PyErr_Occurred(tstate));
 
     while (!gc_list_is_empty(collectable)) {
+        deleted++;
         PyGC_Head *gc = GC_NEXT(collectable);
         PyObject *op = FROM_GC(gc);
 
@@ -1162,6 +1164,7 @@ delete_garbage(PyThreadState *tstate, GCState *gcstate,
             gc_list_move(gc, old);
         }
     }
+    return deleted;
 }
 
 /* Clear all free lists
@@ -1639,8 +1642,7 @@ gc_collect_region(PyThreadState *tstate,
     * the reference cycles to be broken.  It may also cause some objects
     * in finalizers to be freed.
     */
-    stats->collected += gc_list_size(&final_unreachable);
-    delete_garbage(tstate, gcstate, &final_unreachable, to);
+    stats->collected += delete_garbage(tstate, gcstate, &final_unreachable, to);
     validate_consistent_old_space(to);
 
     /* Collect statistics on uncollectable objects found and print