application.rb

config.middleware.tap do |middleware|
  killer = PassengerKiller.new
  
  # Max requests per worker
  middleware.insert_before(
    Rack::Sendfile,
    Middleware, limiter_klass: RequestLimiter, killer: killer, min: 4096, max: 5120)
  
# Max memory size (RSS) per worker
  middleware.insert_before(
    Rack::Sendfile,
    Middleware, limiter_klass: MemoryLimiter, killer: killer, min: 300 * (1024**2), max: 400 * (1024**2))
end