diff -r bb67b810aac1 Objects/listobject.c
--- a/Objects/listobject.c	Mon Feb 23 07:56:13 2015 -0800
+++ b/Objects/listobject.c	Tue Feb 24 10:01:05 2015 +0200
@@ -1955,26 +1955,41 @@ listsort(PyListObject *self, PyObject *a
         lo.values = NULL;
     }
     else {
+        PyObject *args;
+        args = PyTuple_New(1);
+        if (args == NULL)
+            return NULL;
         if (saved_ob_size < MERGESTATE_TEMP_SIZE/2)
             /* Leverage stack space we allocated but won't otherwise use */
             keys = &ms.temparray[saved_ob_size+1];
         else {
             keys = PyMem_MALLOC(sizeof(PyObject *) * saved_ob_size);
-            if (keys == NULL)
+            if (keys == NULL) {
+                Py_DECREF(args);
                 return NULL;
+            }
         }
 
         for (i = 0; i < saved_ob_size ; i++) {
-            keys[i] = PyObject_CallFunctionObjArgs(keyfunc, saved_ob_item[i],
-                                                   NULL);
+            if (Py_REFCNT(args) != 1) {
+                Py_DECREF(args);
+                args = PyTuple_New(1);
+            }
+            Py_INCREF(saved_ob_item[i]);
+            PyTuple_SET_ITEM(args, 0, saved_ob_item[i]);
+            keys[i] = PyObject_Call(keyfunc, args, NULL);
+            Py_DECREF(saved_ob_item[i]);
+            PyTuple_SET_ITEM(args, 0, NULL);
             if (keys[i] == NULL) {
                 for (i=i-1 ; i>=0 ; i--)
                     Py_DECREF(keys[i]);
                 if (saved_ob_size >= MERGESTATE_TEMP_SIZE/2)
                     PyMem_FREE(keys);
+                Py_DECREF(args);
                 goto keyfunc_fail;
             }
         }
+        Py_DECREF(args);
 
         lo.keys = keys;
         lo.values = saved_ob_item;
diff -r bb67b810aac1 Python/bltinmodule.c
--- a/Python/bltinmodule.c	Mon Feb 23 07:56:13 2015 -0800
+++ b/Python/bltinmodule.c	Tue Feb 24 10:01:05 2015 +0200
@@ -479,6 +479,7 @@ typedef struct {
     PyObject_HEAD
     PyObject *func;
     PyObject *it;
+    PyObject *args;  /* cached args tuple */
 } filterobject;
 
 static PyObject *
@@ -508,6 +509,12 @@ filter_new(PyTypeObject *type, PyObject 
     Py_INCREF(func);
     lz->func = func;
     lz->it = it;
+    lz->args = PyTuple_New(1);
+    if (lz->args == NULL) {
+        Py_DECREF(it);
+        Py_DECREF(func);
+        return NULL;
+    }
 
     return (PyObject *)lz;
 }
@@ -518,6 +525,7 @@ filter_dealloc(filterobject *lz)
     PyObject_GC_UnTrack(lz);
     Py_XDECREF(lz->func);
     Py_XDECREF(lz->it);
+    Py_XDECREF(lz->args);
     Py_TYPE(lz)->tp_free(lz);
 }
 
@@ -547,8 +555,21 @@ filter_next(filterobject *lz)
             ok = PyObject_IsTrue(item);
         } else {
             PyObject *good;
-            good = PyObject_CallFunctionObjArgs(lz->func,
-                                                item, NULL);
+            PyObject *args = lz->args;
+            if (Py_REFCNT(args) != 1) {
+                args = PyTuple_New(1);
+                if (args == NULL) {
+                    Py_DECREF(item);
+                    return NULL;
+                }
+                Py_DECREF(lz->args);
+                lz->args = args;
+            }
+            Py_INCREF(args);
+            PyTuple_SET_ITEM(args, 0, item);
+            good = PyObject_Call(lz->func, args, NULL);
+            PyTuple_SET_ITEM(args, 0, NULL);
+            Py_DECREF(args);
             if (good == NULL) {
                 Py_DECREF(item);
                 return NULL;
@@ -1418,6 +1439,7 @@ typedef struct {
     PyObject_HEAD
     PyObject *iters;
     PyObject *func;
+    PyObject *argtuple;  /* cached args tuple */
 } mapobject;
 
 static PyObject *
@@ -1461,6 +1483,12 @@ map_new(PyTypeObject *type, PyObject *ar
     func = PyTuple_GET_ITEM(args, 0);
     Py_INCREF(func);
     lz->func = func;
+    lz->argtuple = PyTuple_New(PyTuple_Size(lz->iters));
+    if (lz->argtuple == NULL) {
+        Py_DECREF(iters);
+        Py_DECREF(func);
+        return NULL;
+    }
 
     return (PyObject *)lz;
 }
@@ -1471,6 +1499,7 @@ map_dealloc(mapobject *lz)
     PyObject_GC_UnTrack(lz);
     Py_XDECREF(lz->iters);
     Py_XDECREF(lz->func);
+    Py_DECREF(lz->argtuple);
     Py_TYPE(lz)->tp_free(lz);
 }
 
@@ -1487,23 +1516,35 @@ map_next(mapobject *lz)
 {
     PyObject *val;
     PyObject *argtuple;
-    PyObject *result;
+    PyObject *result = NULL;
     Py_ssize_t numargs, i;
 
-    numargs = PyTuple_Size(lz->iters);
-    argtuple = PyTuple_New(numargs);
-    if (argtuple == NULL)
-        return NULL;
+    argtuple = lz->argtuple;
+    numargs = PyTuple_Size(argtuple);
+    if (Py_REFCNT(argtuple) != 1) {
+        argtuple = PyTuple_New(numargs);
+        if (argtuple == NULL)
+            return NULL;
+        Py_DECREF(lz->argtuple);
+        lz->argtuple = argtuple;
+    }
+    Py_INCREF(argtuple);
 
     for (i=0 ; i<numargs ; i++) {
         val = PyIter_Next(PyTuple_GET_ITEM(lz->iters, i));
         if (val == NULL) {
-            Py_DECREF(argtuple);
-            return NULL;
+            numargs = i;
+            goto done;
         }
         PyTuple_SET_ITEM(argtuple, i, val);
     }
     result = PyObject_Call(lz->func, argtuple, NULL);
+done:
+    for (i = 0; i < numargs; i++) {
+        val = PyTuple_GET_ITEM(argtuple, i);
+        PyTuple_SET_ITEM(argtuple, i, NULL);
+        Py_DECREF(val);
+    }
     Py_DECREF(argtuple);
     return result;
 }