[Zope] 2b6/zserver/redhat linux - python process seems to be growing ?

I have a ZODB about 5.4 mb and what appears to be a normal healthy zope 2b6 except that whenever I check, the size of the python processes (as revealed by top) seems to be expanding steadily. It starts out around 7.54mB and is currently 34.5mB or so... Anyone else noticed this or is it just me ? Flushing the cache seems to make no difference. At what point should I start wondering about memory leaks ?