That does sound nifty. How does this stack up to the "HotSpot" optimizations that Java and
Im pretty sure the HotSpot name in Java is due to the JIT compilation of "Hot" methods/code.
Regarding the memory then most garbage collecting VMs will probably touch all the used (or even allocated) pages when performing a full garbage sweep so that will mean sucky performance if much of it is in swap. Garbage collecting VMs may gain some by the use of a compacting GC which removes fragmentation and thus keeps the number of allocated pages to a minimum. All in all, the VM will probably unswap all its pages at each GC but keep the number of pages allocated to a minimum.
...when fits of creativity run strong, more than one programmer or writer has been known to abandon the desktop for the more spacious floor. - Fred Brooks, Jr.