In search of an appropriate RLIMIT_MEMLOCK default

64KB is a number from a medieval era and an indication that the whole mechanism needs to be rethought. Do away with the hard limit entirely and put that effort into making the OOM killer more robust.

Visible arbitrary limits like this are stable ABI, whether we like it or not. By increasing them you subconsciously train developers to take that number for granted and grow their software towards it, and we've seen the end result of that in this area with glibc's gigantic thread stacks leading to supposedly portable software not working in musl. We need good backpressure mechanisms, not more bufferbloat.