[pbalcer]

Yes, but to accomplish that you would have to use the MAP_FIXED flag, which is quite dangerous because it can replace previous mappings. That can lead to problems with dynamic memory allocation since almost all malloc() implementations use anonymous mmap.

[repolfx]

Yes but this is a trivial problem to fix on 64 bit machines. There's so much address space the kernel can just be told to never pick certain address ranges for unfixed mmaps, leaving the rest of the address space free for persistent heaps.

The actual hard part of persistent heaps isn't the persistence part. It's transactionality and upgrade management.