Embodiments of the present invention provide memory optimization by phase-dependent data residency. Application programs are profiled a priori or in real time for temporal memory usage. Memory regions such as initialization data are proactively removed from memory when the application transitions to a new phase. A hypervisor monitors application activity and coordinates the removal of memory regions that are no longer needed by the application. Additionally, memory regions that are anticipated to be needed in the future are proactively preloaded.