currentOp() doesn't indicate an eval is in progress.
killOp() won't kill it either.
curop seg fault
killop not robust
in v8, can't do a $where with a function() inside of db.eval
in spidermonkey js impl, killop can be caught as a js exception
killop does not work for nested ops
v8 Issue 708
killall may fail in v8
when multiple map reduce jobs are running and one is holding the js mutex indefinitely, it is not obvious which is hogging the js mutex
curop should show op num of parent ops