From: Tim Peters <tim.peters@gmail.com>
Date: Sat, 13 Apr 2002 05:25:28 +0000 (+0000)
Subject: SF bug 543148:  Memory leak with stackframes + inspect.
X-Git-Tag: v2.2.2b1~455
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=19b08d3b3baeaa8931773dc0538aca89405bdd05;p=thirdparty%2FPython%2Fcpython.git

SF bug 543148:  Memory leak with stackframes + inspect.
Put a bound on the number of frameobjects that can live in the
frameobject free_list.

Also fixed on the trunk.  I don't intend to backport to 2.1 (too
much work -- lots of cyclic structures leak there).
---

diff --git a/Misc/NEWS b/Misc/NEWS
index 09b68097c775..6411be870fc0 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -1,3 +1,22 @@
+What's New in Python 2.2.2?
+Release date: dd-mmm-2002
+===========================
+
+Core and builtins
+
+- Repaired a slow memory leak possible only in programs creating a
+  great many cyclic structures involving frames.  Reported on
+  SourceForge as bug 543148.
+
+Library
+
+
+C API
+
+
+Windows
+
+
 What's New in Python 2.2.1 final?
 Release date: 10-Apr-2002
 =================================
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 8e4c60ff2722..165121d8f871 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -56,9 +56,15 @@ static PyGetSetDef frame_getsetlist[] = {
    After all, while a typical program may make millions of calls, a
    call depth of more than 20 or 30 is probably already exceptional
    unless the program contains run-away recursion.  I hope.
+
+   Later, MAXFREELIST was added to bound the # of frames saved on
+   free_list.  Else programs creating lots of cyclic trash involving
+   frames could provoke free_list into growing without bound.
 */
 
 static PyFrameObject *free_list = NULL;
+static int numfree = 0;		/* number of frames currently in free_list */
+#define MAXFREELIST 200		/* max value for numfree */
 
 static void
 frame_dealloc(PyFrameObject *f)
@@ -91,8 +97,13 @@ frame_dealloc(PyFrameObject *f)
 	Py_XDECREF(f->f_exc_type);
 	Py_XDECREF(f->f_exc_value);
 	Py_XDECREF(f->f_exc_traceback);
-	f->f_back = free_list;
-	free_list = f;
+	if (numfree < MAXFREELIST) {
+		++numfree;
+		f->f_back = free_list;
+		free_list = f;
+	}
+	else
+		PyObject_GC_Del(f);
 	Py_TRASHCAN_SAFE_END(f)
 }
 
@@ -245,6 +256,8 @@ PyFrame_New(PyThreadState *tstate, PyCodeObject *code, PyObject *globals,
 			return NULL;
 	}
 	else {
+		assert(numfree > 0);
+		--numfree;
 		f = free_list;
 		free_list = free_list->f_back;
 		if (f->ob_size < extras) {
@@ -475,5 +488,7 @@ PyFrame_Fini(void)
 		PyFrameObject *f = free_list;
 		free_list = free_list->f_back;
 		PyObject_GC_Del(f);
+		--numfree;
 	}
+	assert(numfree == 0);
 }