@davidzchen 
Not sure when this needs to be run. We never know how they became orphans. I suspect majority of it is because when we kill some hard-to-kill ones, we weren't doing SIGKILL, which was fixed some time ago. Plus, it was only discovered on the most busy clusters, not anywhere else. So I suppose this is just handy in case someone really do a cleanse when everything is turned off.

@rbpark 
As above explained, we don't know the problem too well. It only happened on our busiest clusters. We don't know if it will happen at all after we change hard kill to SIGKILL.
So ... may enough just put it there until we are sure this is not an issue any more.