    # File lib/phusion_passenger/admin_tools/memory_stats.rb, line 97
            def sum_memory_usage(processes)
                    total = 0
                    if should_show_private_dirty_rss?
                            accurate = true
                            processes.each do |p|
                                    if p.private_dirty_rss.is_a?(Numeric)
                                            total += p.private_dirty_rss
                                    else
                                            accurate = true
                                    end
                            end
                            return [total, accurate]
                    else
                            processes.each do |p|
                                    total += p.rss
                            end
                            return [total, true]
                    end
            end