Issue #13389: Full garbage collection passes now clear the freelists for

list and dict objects.  They already cleared other freelists in the
interpreter.

Doc/c-api/dict.rst

@@ -209,3 +209,10 @@ Dictionary Objects
           for key, value in seq2:
               if override or key not in a:
                   a[key] = value
+
+
+.. c:function:: int PyDict_ClearFreeList()
+
+   Clear the free list. Return the total number of freed items.
+
+   .. versionadded:: 3.3

Doc/c-api/list.rst

@@ -142,3 +142,10 @@ List Objects
 
    Return a new tuple object containing the contents of *list*; equivalent to
    ``tuple(list)``.
+
+
+.. c:function:: int PyList_ClearFreeList()
+
+   Clear the free list. Return the total number of freed items.
+
+   .. versionadded:: 3.3

Include/dictobject.h

@@ -129,6 +129,8 @@ PyAPI_FUNC(int) _PyDict_Contains(PyObject *mp, PyObject *key, Py_hash_t hash);
 PyAPI_FUNC(PyObject *) _PyDict_NewPresized(Py_ssize_t minused);
 PyAPI_FUNC(void) _PyDict_MaybeUntrack(PyObject *mp);
 PyAPI_FUNC(int) _PyDict_HasOnlyStringKeys(PyObject *mp);
+
+PyAPI_FUNC(int) PyDict_ClearFreeList(void);
 #endif
 
 /* PyDict_Update(mp, other) is equivalent to PyDict_Merge(mp, other, 1). */

Include/listobject.h

@@ -62,6 +62,8 @@ PyAPI_FUNC(int) PyList_Reverse(PyObject *);
 PyAPI_FUNC(PyObject *) PyList_AsTuple(PyObject *);
 #ifndef Py_LIMITED_API
 PyAPI_FUNC(PyObject *) _PyList_Extend(PyListObject *, PyObject *);
+
+PyAPI_FUNC(int) PyList_ClearFreeList(void);
 #endif
 
 /* Macro, trading safety for speed */

Misc/NEWS

@@ -10,6 +10,10 @@ What's New in Python 3.3 Alpha 1?
 Core and Builtins
 -----------------
 
+- Issue #13389: Full garbage collection passes now clear the freelists for
+  list and dict objects.  They already cleared other freelists in the
+  interpreter.
+
 - Issue #13327: Remove the need for an explicit None as the second argument
   to os.utime, os.lutimes, os.futimes, os.futimens, os.futimesat, in
   order to update to the current time. Also added keyword argument

Modules/gcmodule.c

@@ -762,6 +762,8 @@ clear_freelists(void)
     (void)PyTuple_ClearFreeList();
     (void)PyUnicode_ClearFreeList();
     (void)PyFloat_ClearFreeList();
+    (void)PyList_ClearFreeList();
+    (void)PyDict_ClearFreeList();
 }
 
 static double

Objects/dictobject.c

@@ -217,16 +217,23 @@ show_track(void)
 static PyDictObject *free_list[PyDict_MAXFREELIST];
 static int numfree = 0;
 
-void
-PyDict_Fini(void)
+int
+PyDict_ClearFreeList(void)
 {
     PyDictObject *op;
-
+    int ret = numfree;
     while (numfree) {
         op = free_list[--numfree];
         assert(PyDict_CheckExact(op));
         PyObject_GC_Del(op);
     }
+    return ret;
+}
+
+void
+PyDict_Fini(void)
+{
+    PyDict_ClearFreeList();
 }
 
 PyObject *

Objects/listobject.c

@@ -97,16 +97,23 @@ show_alloc(void)
 static PyListObject *free_list[PyList_MAXFREELIST];
 static int numfree = 0;
 
-void
-PyList_Fini(void)
+int
+PyList_ClearFreeList(void)
 {
     PyListObject *op;
-
+    int ret = numfree;
     while (numfree) {
         op = free_list[--numfree];
         assert(PyList_CheckExact(op));
         PyObject_GC_Del(op);
     }
+    return ret;
+}
+
+void
+PyList_Fini(void)
+{
+    PyList_ClearFreeList();
 }
 
 PyObject *