INIT_FLIST_HEAD(&td->io_log_list);
INIT_FLIST_HEAD(&td->io_hist_list);
INIT_FLIST_HEAD(&td->verify_list);
INIT_FLIST_HEAD(&td->io_log_list);
INIT_FLIST_HEAD(&td->io_hist_list);
INIT_FLIST_HEAD(&td->verify_list);
pthread_mutex_init(&td->io_u_lock, NULL);
td->io_hist_tree = RB_ROOT;
pthread_mutex_init(&td->io_u_lock, NULL);
td->io_hist_tree = RB_ROOT;