Currently, there are no mechanisms for the host or UML to communicate memory management information to each other. This results in memory management decisions being taken in isolation, which, in many situations, hurts the overall efficiency of the host and increases the effective footprint of UML on the host.
Multiple UMLs compete with each other for memory. Since they don't have any information about what the other UMLs are doing, their memory management decisions taken in isolation will hurt each other and the host.
We need mechanisms for the UMLs to communicate memory management information to the to the host. This would allow it to integrate this information with its own and pass it back in some form back to the UMLs, again using some new mechanisms.