파이프가 가득 차 있는데 왜 작가를 깨우나요?

https://elixir.bootlin.com/linux/v5.19/source/fs/pipe.c#L247

파이프가 가득 차면 리더가 깨어나서 데이터를 읽어야 하지 않나요?

    /*
     * We only wake up writers if the pipe was full when we started
     * reading in order to avoid unnecessary wakeups.
     *
     * But when we do wake up writers, we do so using a sync wakeup
     * (WF_SYNC), because we want them to get going and generate more
     * data for us.
     */
    was_full = pipe_full(pipe->head, pipe->tail, pipe->max_usage);