FYI, when I performed my simple Vdsm leak test some time ago, I've found a leak in Python multiprocessing module, where multiprocessing.util._afterfork_registry dictionary grows on each supervdsm call. It's not much dramatic from the point of memory usage but maybe the possibly large dictionary can cause other performance problems. It's better to have this fixed and it looks like a Python bug, reported here: https://bugs.python.org/issue26180.