post-5.1: vmmap


policy-based allocator, different strategies for different areas
allows clean, small address selection logic
different strategies for userland and kernel
i386 madness (bottom executable, top writable) easier

modular, address selectors are tiny modules

policies allow us to cope with the JIT based stuff
nightmare. what did they smoke?
javascript engines, java

goals: speed, speed, better randomization, speed
currently in compat mode, old strategy in new framework