Thread.interrupt()源码跟踪

1 JDK源码跟踪

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

    synchronized (blockerLock) {
        Interruptible b = blocker;
        if (b != null) {
            interrupt0();           // Just to set the interrupt flag
            b.interrupt(this);
            return;
        }
    }
    interrupt0();
}

private native void interrupt0();

2 OpenJDK源码跟踪

• jdk源码（JNI注册）

// jdk/src/share/native/java/lang/Thread.c:43
static JNINativeMethod methods[] = {
    {"start0","()V",(void *)&JVM_StartThread},{"stop0","(" OBJ ")V",(void *)&JVM_StopThread},{"isAlive","()Z",(void *)&JVM_IsThreadAlive},{"suspend0",(void *)&JVM_SuspendThread},{"resume0",(void *)&JVM_ResumeThread},{"setPriority0","(I)V",(void *)&JVM_SetThreadPriority},{"yield",(void *)&JVM_Yield},{"sleep","(J)V",(void *)&JVM_Sleep},{"currentThread","()" THD,(void *)&JVM_CurrentThread},{"countStackFrames","()I",(void *)&JVM_CountStackFrames},{"interrupt0",(void *)&JVM_Interrupt},{"isInterrupted","(Z)Z",(void *)&JVM_IsInterrupted},{"holdsLock","(" OBJ ")Z",(void *)&JVM_HoldsLock},{"getThreads","()[" THD,(void *)&JVM_GetAllThreads},{"dumpThreads","([" THD ")[[" STE,(void *)&JVM_DumpThreads},{"setNativeName","(" STR ")V",(void *)&JVM_SetNativeThreadName},};

// jdk/src/share/javavm/export/jvm.h:254
JNIEXPORT void JNICALL
JVM_Interrupt(JNIEnv *env,jobject thread);

• java虚拟机（HotSpot实现）：

// hotspot/src/share/prims/jvm.cpp:3289
JVM_ENTRY(void,JVM_Interrupt(JNIEnv* env,jobject jthread))
  JVMWrapper("JVM_Interrupt");

  // Ensure that the C++ Thread and OSThread structures aren't freed before we operate
  oop java_thread = JNIHandles::resolve_non_null(jthread);
  MutexLockerEx ml(thread->threadObj() == java_thread ? NULL : Threads_lock);
  // We need to re-resolve the java_thread,since a GC might have happened during the
  // acquire of the lock
  JavaThread* thr = java_lang_Thread::thread(JNIHandles::resolve_non_null(jthread));
  if (thr != NULL) {
    Thread::interrupt(thr);
  }
JVM_END

// hotspot/src/share/vm/runtime/thraed.cpp:634
ParkEvent * _ParkEvent ;   // for synchronized()
ParkEvent * _SleepEvent ; // for Thread.sleep
ParkEvent * _MutexEvent ; // for native internal Mutex/Monitor,互斥锁
ParkEvent * _MuxEvent ;   // for low-level muxAcquire-muxRelease，共享锁

// hotspot/src/share/vm/runtime/thraed.cpp:804
void Thread::interrupt(Thread* thread) {
  trace("interrupt",thread);
  debug_only(check_for_dangling_thread_pointer(thread);)
  os::interrupt(thread);
}

// hotspot/src/hotspot/os/linux/vm/os_linux.cpp:4192
void os::interrupt(Thread* thread) {
  assert(Thread::current() == thread || Threads_lock->owned_by_self(),"possibility of dangling Thread pointer");

  OSThread* osthread = thread->osthread();

  if (!osthread->interrupted()) {
    osthread->set_interrupted(true);
    // More than one thread can get here with the same value of osthread,// resulting in multiple notifications.  We do,however,want the store
    // to interrupted() to be visible to other threads before we execute unpark().
    OrderAccess::fence();
    ParkEvent * const slp = thread->_SleepEvent ;
    // Thread.sleep方法继续运行
    if (slp != NULL) slp->unpark() ;
  }

  // For JSR166. Unpark event if interrupt status already was set
  if (thread->is_Java_thread())
    ((JavaThread*)thread)->parker()->unpark();

  ParkEvent * ev = thread->_ParkEvent ;
  if (ev != NULL) ev->unpark() ;
}

// hotspot/src/share/vm/runtime/osThread.hpp:很短自己看
volatile jint _interrupted; // Thread.isInterrupted state    

volatile bool interrupted() const{ 
    return _interrupted != 0;
}

void set_interrupted(bool z){ 
    _interrupted = z ? 1 : 0; 
}