Limit free list of method and builtin function objects to 256 entries each.

1 files changed, 18 insertions, 5 deletions

diff --git a/Objects/classobject.c b/Objects/classobject.c
index 9f364e2e88..a9e8c6a9ea 100644
--- a/Objects/classobject.c
+++ b/Objects/classobject.c
@@ -4,10 +4,16 @@
 #include "Python.h"
 #include "structmember.h"
 
+/* Free list for method objects to safe malloc/free overhead
+ * The im_self element is used to chain the elements.
+ */
+static PyMethodObject *free_list;
+static int numfree = 0;
+#define MAXFREELIST 256
+
 #define TP_DESCR_GET(t) \
     (PyType_HasFeature(t, Py_TPFLAGS_HAVE_CLASS) ? (t)->tp_descr_get : NULL)
 
-
 /* Forward */
 static PyObject *class_lookup(PyClassObject *, PyObject *,
 			      PyClassObject **);
@@ -2193,8 +2199,6 @@ PyTypeObject PyInstance_Type = {
    In case (b), im_self is NULL
 */
 
-static PyMethodObject *free_list;
-
 PyObject *
 PyMethod_New(PyObject *func, PyObject *self, PyObject *klass)
 {
@@ -2207,6 +2211,7 @@ PyMethod_New(PyObject *func, PyObject *self, PyObject *klass)
 	if (im != NULL) {
 		free_list = (PyMethodObject *)(im->im_self);
 		PyObject_INIT(im, &PyMethod_Type);
+		numfree--;
 	}
 	else {
 		im = PyObject_GC_New(PyMethodObject, &PyMethod_Type);
@@ -2332,8 +2337,14 @@ instancemethod_dealloc(register PyMethodObject *im)
 	Py_DECREF(im->im_func);
 	Py_XDECREF(im->im_self);
 	Py_XDECREF(im->im_class);
-	im->im_self = (PyObject *)free_list;
-	free_list = im;
+	if (numfree < MAXFREELIST) {
+		im->im_self = (PyObject *)free_list;
+		free_list = im;
+		numfree++;
+	}
+	else {
+		PyObject_GC_Del(im);
+	}
 }
 
 static int
@@ -2620,5 +2631,7 @@ PyMethod_Fini(void)
 		PyMethodObject *im = free_list;
 		free_list = (PyMethodObject *)(im->im_self);
 		PyObject_GC_Del(im);
+		numfree--;
 	}
+	assert(numfree == 0);
 }