Based on request traffic or maximum memory? For the JVM there is -Xmx512m to set the max heap size (512MB in this case). Or are you thinking of something more organic so individual containers could overcommit on memory, and the OOM killer would first send a "collect" signal to all the containers that could GC (and also give the memory back).
Yes when I say cooperative I mean nice processes are opting in to being told what and when to do something (change heap size, run a light or heavy collection, etc) apart from their own internal view of affairs.
