Thanks for your reply, jtoomim. Also, I just saw your latest commit and I think it's still leaking the feecache variable. This is the fix I've been using (sorry, I have no GH account):
--- a/p2pool/bitcoin/helper.py
+++ b/p2pool/bitcoin/helper.py
@@ -111,7 +111,7 @@ def getwork(bitcoind, use ...