Memory leak in Xend, resulting in long garbage collector runs.

In the method xen.xend.XendStateStore.XendStateStore.load_state and
xen.xend.XendStateStore.XendStateStore.save_state the minidom objects used to
load/save the current state of a device type, can't be freed by the python
garbage collector after all references to the top node are cleared, because of
cyclic references between the DOM nodes. So memory usage of xend increases
after calling these methods.
To solve this problem, the unlink() method must be called for a minidom object
before the last reference to the top node is cleared (see python docs). This
breaks the cyclic references, so the garbage collector can free these objects.

Signed-off-by: juergen.gross@ts.fujitsu.com


# HG changeset patch
# User juergen.gross@ts.fujitsu.com
# Date 1249300432 -7200
# Node ID d40abdac1cf42ae552f727750cd0cca0b8d32361
# Parent  41b2c4e4f6746c638192b88ea37d3d25196850ad
Avoid memory leak in xend

diff -r 41b2c4e4f674 -r d40abdac1cf4 tools/python/xen/xend/XendStateStore.py
--- a/tools/python/xen/xend/XendStateStore.py	Wed Jul 29 09:20:46 2009 +0100
+++ b/tools/python/xen/xend/XendStateStore.py	Mon Aug 03 13:53:52 2009 +0200
@@ -147,6 +147,7 @@
                     cls_dict[val_name] = bool(int(val_text))
             state[uuid] = cls_dict
 
+        dom.unlink()
         return state
 
     def save_state(self, cls, state):
@@ -226,5 +227,5 @@
                     node.appendChild(val_node)
 
         open(xml_path, 'w').write(doc.toprettyxml())
-        
+        doc.unlink()