http://kernelnewbies.org/FAQ/DoWhile0
그외참고 튜닝? http://jh4hj.tistory.com/entry/%EB%A9%94%EB%AA%A8%EB%A6%AC-%EB%94%94%EB%B2%84%EA%B9%85%EC%9D%84-%EC%9C%84%ED%95%9C-%EC%B9%9C%EA%B5%AC