Use readable READ/WRITE macros instead of magic numbers.
Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
         * that a group's limit are dropped suddenly and we don't want to
         * account recently dispatched IO with new low rate.
         */
-       throtl_start_new_slice(tg, 0);
-       throtl_start_new_slice(tg, 1);
+       throtl_start_new_slice(tg, READ);
+       throtl_start_new_slice(tg, WRITE);
 
        if (tg->flags & THROTL_TG_PENDING) {
                tg_update_disptime(tg);