[Python-checkins] python/dist/src/Objects frameobject.c,2.59.6.1,2.59.6.2

[tim_one@sourceforge.net]

Update of /cvsroot/python/python/dist/src/Objects
In directory usw-pr-cvs1:/tmp/cvs-serv3938/221/Objects

Modified Files:
      Tag: release22-maint
	frameobject.c 
Log Message:
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).


Index: frameobject.c
===================================================================
RCS file: /cvsroot/python/python/dist/src/Objects/frameobject.c,v
retrieving revision 2.59.6.1
retrieving revision 2.59.6.2
diff -C2 -d -r2.59.6.1 -r2.59.6.2
*** frameobject.c	28 Mar 2002 20:36:50 -0000	2.59.6.1
--- frameobject.c	13 Apr 2002 05:25:28 -0000	2.59.6.2
***************
*** 57,63 ****
--- 57,69 ----
     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
***************
*** 92,97 ****
  	Py_XDECREF(f->f_exc_value);
  	Py_XDECREF(f->f_exc_traceback);
! 	f->f_back = free_list;
! 	free_list = f;
  	Py_TRASHCAN_SAFE_END(f)
  }
--- 98,108 ----
  	Py_XDECREF(f->f_exc_value);
  	Py_XDECREF(f->f_exc_traceback);
! 	if (numfree < MAXFREELIST) {
! 		++numfree;
! 		f->f_back = free_list;
! 		free_list = f;
! 	}
! 	else
! 		PyObject_GC_Del(f);
  	Py_TRASHCAN_SAFE_END(f)
  }
***************
*** 246,249 ****
--- 257,262 ----
  	}
  	else {
+ 		assert(numfree > 0);
+ 		--numfree;
  		f = free_list;
  		free_list = free_list->f_back;
***************
*** 476,479 ****
--- 489,494 ----
  		free_list = free_list->f_back;
  		PyObject_GC_Del(f);
+ 		--numfree;
  	}
+ 	assert(numfree == 0);
  }