[feature request] backport lua 5.4 generational GC

[suikabreaker]

ATT.

I'm developing using OpenResty and have put heavy logic on lua(with relatively large in-memory data and lot of string manipulation, and a lot of functions), and I noticed that those permanent GC object also slows down GC.

If we can mannually specify object as permanent it may also be sufficient for my case.

[suikabreaker]

here is an example of backporting:
dibyendumajumdar/ravi#196

[suikabreaker]

and another example(for manully disable GC for specified object):
https://yuerer.com/Lua-GC%E5%9E%83%E5%9C%BE%E5%9B%9E%E6%94%B6%E4%BC%98%E5%8C%96%E6%96%B9%E6%A1%88/

[Summer-Time-2020]

I have the same problem

[hankai17]

@suikabreaker
Is your problem solved?

[hankai17]

#210