Ruby 2+ environment variables to tune GC and memory bloat to a minimum on large apps

ruby-memory-env.sh

# Discourse Settings
export RUBY_GC_HEAP_INIT_SLOTS=997339
export RUBY_GC_HEAP_FREE_SLOTS=626600
export RUBY_GC_HEAP_GROWTH_FACTOR=1.03
export RUBY_GC_HEAP_GROWTH_MAX_SLOTS=88792
export RUBY_GC_HEAP_OLDOBJECT_LIMIT_FACTOR=2.4
export RUBY_GC_MALLOC_LIMIT=34393793
export RUBY_GC_MALLOC_LIMIT_MAX=41272552
export RUBY_GC_MALLOC_LIMIT_GROWTH_FACTOR=1.32
export RUBY_GC_OLDMALLOC_LIMIT=39339204
export RUBY_GC_OLDMALLOC_LIMIT_MAX=47207045
export RUBY_GC_OLDMALLOC_LIMIT_GROWTH_FACTOR=1.2

# https://www.mikeperham.com/2018/04/25/taming-rails-memory-bloat/
export MALLOC_ARENA_MAX=2

# Also, make sure you are using jemalloc-linked Ruby