Tom, sorry, I've been traveling from India and hence the late response.
I forgot to add I ran 'test-patch' locally on 12/29 since the patch was originally blocked on
YARN-2. My bad.
The patch is trivial and just adds a experimental config variables and was around for a while before I pushed it to make hadoop-2.0.3-alpha. If you see any issues please let me know and I'll fix them. Thanks.