java - Thread 上的 eetop 字段是做什么用的？

Question

我找不到文档，只有 the following discussion这不是很清楚它的用途。

Answer 1

Note: JDK1.1 and before had a privateInfo_offset field which was used for the platform thread structure, and a eetop offset which was used for thread local storage (and unused by the HotSpot VM). In JDK1.2 the two structures merged, so in the HotSpot VM we just use the eetop field for the thread instead of the privateInfo_offset.

它是 JRE 源，它是指向 JVM 的底层操作系统级 native 线程实例的指针 (ref)。在最新的 JDK 源代码中，文件 hotspot/src/share/vm/classfile/javaClasses.cpp 仍然包含该字段，并且注释也在那里。

在对应的java类中，(jdk/src/share/classes/java/lang/Thread.java)，声明为private long(可能是因为Java 不知道指针)。