--- Python-2.5.2/Objects/obmalloc.c.old	2008-03-19 19:03:59.000000000 +0900
+++ Python-2.5.2/Objects/obmalloc.c	2008-03-19 19:05:45.000000000 +0900
@@ -2,6 +2,23 @@
 
 #ifdef WITH_PYMALLOC
 
+#define WITH_VALGRIND
+
+#ifdef WITH_VALGRIND
+#include <valgrind/memcheck.h>
+
+/* If we're using GCC, use __builtin_expect() to reduce overhead of
+   the valgrind checks */
+#if defined(__GNUC__) && (__GNUC__ > 2) && defined(__OPTIMIZE__)
+#  define EXPECT(value, expected) __builtin_expect((value), (expected))
+#else
+#  define EXPECT(value, expected) (value)
+#endif
+
+/* -1 indicates that we haven't checked that we're running on valgrind yet. */
+static int running_on_valgrind = -1;
+#endif
+
 /* An object allocator for Python.
 
    Here is an introduction to the layers of the Python memory architecture,
@@ -726,6 +743,14 @@
 	poolp next;
 	uint size;
 
+#ifdef WITH_VALGRIND
+        if (EXPECT(running_on_valgrind == -1, 0)) {
+                running_on_valgrind = RUNNING_ON_VALGRIND;
+        }
+        if (EXPECT(running_on_valgrind, 0))
+                goto redirect;
+#endif
+
 	/*
 	 * This implicitly redirects malloc(0).
 	 */
@@ -916,6 +941,13 @@
 	if (p == NULL)	/* free(NULL) has no effect */
 		return;
 
+#ifdef WITH_VALGRIND
+        if (EXPECT(running_on_valgrind > 0, 0)) {
+                free(p);
+                return;
+        }
+#endif
+
 	pool = POOL_ADDR(p);
 	if (Py_ADDRESS_IN_RANGE(p, pool)) {
 		/* We allocated this address. */