参考：

JVM内存分区及作用（JDK8）

https://blog.csdn.net/BigBug_500/article/details/104734957

java 进程占用系统内存过高分析

https://blog.csdn.net/fxh13579/article/details/104754340

Java之jvm和线程的内存

 https://blog.csdn.net/qq_39507276/article/details/123376949

JVM:浅谈CodeCache

https://www.jianshu.com/p/cbab2371b164 

JVM参数与内存模型

https://www.cnblogs.com/lowerma/p/12404423.html

怎么做JDK8的内存调优

https://www.cnblogs.com/heihaozi/p/13417591.html

JVM内存分配(JDK8)

https://blog.csdn.net/paopaodog/article/details/127151177

top命令详解

https://blog.csdn.net/yaomingyang/article/details/78968573

 JVM内存泄漏之MaxDirectMemory

 https://www.jianshu.com/p/dfc847086ee1