From: Guido van Rossum <guido@python.org>
Date: Wed, 9 Jun 1999 15:19:34 +0000 (+0000)
Subject: When deallocating a list, DECREF the items from the end back to the start.
X-Git-Tag: v1.6a1~1261
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=fa71701d46892fe80b1e95279e435533579b3ca7;p=python

When deallocating a list, DECREF the items from the end back to the start.
---

diff --git a/Objects/listobject.c b/Objects/listobject.c
index 05da5dcc0f..0342cdcb38 100644
--- a/Objects/listobject.c
+++ b/Objects/listobject.c
@@ -216,7 +216,12 @@ list_dealloc(op)
 {
 	int i;
 	if (op->ob_item != NULL) {
-		for (i = 0; i < op->ob_size; i++) {
+		/* Do it backwards, for Christian Tismer.
+		   There's a simple test case where somehow this reduces
+		   thrashing when a *very* large list is created and
+		   immediately deleted. */
+		i = op->ob_size;
+		while (--i >= 0) {
 			Py_XDECREF(op->ob_item[i]);
 		}
 		free((ANY *)op->ob_item);