NMT is an optional JVM feature that can be switched off at build time (--disable-jvm-features-nmt). This causes some code complexity and adds another configuration to test (beside NMT off at runtime and the other NMT modes), so the question came up whether we really need NMT to be excludable. Footprint is quite low when off.

After discussing this on hotspot-runtime-dev [1], the general opinion seems to be that we could get rid INCLUDE_NMT and make NMT unconditional.

[1] https://mail.openjdk.java.net/pipermail/hotspot-runtime-dev/2022-January/053504.html