We currently limit the virtual address range span we can use for the heap to 16TB. With some small tweaks to object array marking and how we encode our forwarding entires we are able to increase this span to 128TB.

This would enable MaxHeapSize greater than 1TB to still have some of the same guarantees with respect to virtual address fragmentation that we have when running with heaps equal or smaller than 1TB.

This change would allow us to use a virtual address space up to 128TB on systems which support these sizes.

This enhancement will not change the max MaxHeapSize from 16TB.