java学习-并发-interrupted

/* Interrupt state of the thread - read/written directly by JVM */
    private volatile boolean interrupted;

根据Thread#interrupted可以了解到,interrupted 实际 是线程中止状态,而对于当前字段真实状态是由jvm c++ 代码进行操作的; 且使用volatile保证了其可见性;

public void interrupt() {
        if (this != Thread.currentThread()) {
            checkAccess();

            // thread may be blocked in an I/O operation
            synchronized (blockerLock) {
                Interruptible b = blocker;
                if (b != null) {
                    interrupted = true;
                    interrupt0();  // inform VM of interrupt
                    b.interrupt(this);
                    return;
                }
            }
        }
        interrupted = true;
        // inform VM of interrupt
        interrupt0(); // 这里是调用的native方法
    }

 

对于interrupt0 native 映射 在 thread.c 中 存在 映射定义 "{"interrupt0", "()V", (void *)&JVM_Interrupt}," 

可以看到在 jvm.cpp 中存在 真正执行的代码为

openjdk 15 source - jvm.cpp

JVM_ENTRY(void, JVM_Interrupt(JNIEnv* env, jobject jthread))
  JVMWrapper("JVM_Interrupt");

  ThreadsListHandle tlh(thread);
  JavaThread* receiver = NULL;
  bool is_alive = tlh.cv_internal_thread_to_JavaThread(jthread, &receiver, NULL);
  if (is_alive) { // 首先会判读当前java object(jthread) 中关联的 JavaThread(c++ 对象) 是否存活,JavaThread的存活表示 os线程的存活
    // jthread refers to a live JavaThread.
    receiver->interrupt(); // 此时调用 JavaThread::interrupt方法
  }
JVM_END

 

openjdk 15 source - thread.cpp

// interrupt support

void JavaThread::interrupt() {
  debug_only(check_for_dangling_thread_pointer(this);)

  // For Windows _interrupt_event
  osthread()->set_interrupted(true); // 修改线程的状态:当前方法只有os_windows才会执行,其他平台不会执行

  // For Thread.sleep
  _SleepEvent->unpark(); // 释放当前线程休眠事件

  // For JSR166 LockSupport.park
  parker()->unpark(); 

  // For ObjectMonitor and JvmtiRawMonitor
  _ParkEvent->unpark();
}