关于reloadable属性配置的设计意义

按照文档说明reloadable设置为false，那么这个进程是不会被重启的，但是源码中，还是对这些进程进行重启信号，代码如下：

                // Send reload signal to all child processes.
                $reloadable_pid_array = array();
                foreach (static::$_pidMap as $worker_id => $worker_pid_array) {
                    $worker = static::$_workers[$worker_id];
                    if ($worker->reloadable) {
                        foreach ($worker_pid_array as $pid) {
                            $reloadable_pid_array[$pid] = $pid;
                        }
                    } else {
                        foreach ($worker_pid_array as $pid) {
                            // Send reload signal to a worker process which reloadable is false.
                            \posix_kill($pid, $sig);
                        }
                    }
                }

所以对reloadable设置为false的进程发送信号的意义是？