https://qooah.com/2015/05/27/android-m-%e7%b3%bb%e7%b5%b1%e5%b0%87%e9%87%9d%e5%b0%8d%e6%94%b9%e5%96%84ram%e7%ae%a1%e7%90%86%e5%8f%8a%e8%80%97%e9%9b%bb%e7%ba%8c%e8%88%aa%e5%95%8f%e9%a1%8c/