hotspot的内存

java memory主要分heap memory 和 non-heap memory，其计算公式如下：

Max memory = [-Xmx] + [-XX:MaxPermSize] + number_of_threads * [-Xss]

heap结构 按分代，分young-eden,young-survivor,old 用-Xmn,-Xms,-Xmx来指定。

non-heap结构 包括metaspace,thread stacks,compiled native code,memory allocated by native code -XX:PermSize或-XX:MetaspceSize,-Xss或-XX:ThreadStackSize。　　

J ava的内存管理涉及到如下类：ResourceObj, CHeapObj, StackObj, ValueObj, AllStatic, AllocatedObj(ALLOCATIONSUPER_CLASS_SPEC)

 ((cite: hotspot/src/share/vm/memory/allocation.hpp))
    // All classes in the virtual machine must be subclassed
    // by one of the following allocation classes:
    //
    // For objects allocated in the resource area (see resourceArea.hpp).
    // - ResourceObj
    //
    // For objects allocated in the C-heap (managed by: free & malloc).
    // - CHeapObj
    //
    // For objects allocated on the stack.
    // - StackObj
    //
    // For embedded objects.
    // - ValueObj
    //
    // For classes used as name spaces.
    // - AllStatic

　　

参考文章：

（1）JVM Internals http://blog.jamesdbloom.com/JVMInternals.html

（2）HotSpot を構成するクラスの基底クラス, およびそれらのメモリ管理方法 http://hsmemo.github.io/articles/no28916gIW.html