read-barrier-code.rb

def segv_handler(info)
  # Only triggered if someone tried to read from a MOVED location
  move_all_objects_back(find_page(info.read_address))
end

def compact
  register_segv_handler :segv_handler

  ruby_heap.pages.each do |page|
    move_objects_on(page)
    mprotect(page)
  end

  ruby_heap.pages.each do |page|
    update_references(page)
  end

  ruby_heap.pages.each do |page|
    move_objects_on(page)
    unprotect(page)
  end

  unregister_segv_handler :segv_handler
end