src/hotspot/share/prims/jni.cpp

*** 271,281 ****
  
    JNIHistogramElement::JNIHistogramElement(const char* elementName) {
      _name = elementName;
      uintx count = 0;
  
!     while (Atomic::cmpxchg(1, &JNIHistogram_lock, 0) != 0) {
        while (Atomic::load_acquire(&JNIHistogram_lock) != 0) {
          count +=1;
          if ( (WarnOnStalledSpinLock > 0)
            && (count % WarnOnStalledSpinLock == 0)) {
            warning("JNIHistogram_lock seems to be stalled");
--- 271,281 ----
  
    JNIHistogramElement::JNIHistogramElement(const char* elementName) {
      _name = elementName;
      uintx count = 0;
  
!     while (Atomic::cmpxchg(&JNIHistogram_lock, 0, 1) != 0) {
        while (Atomic::load_acquire(&JNIHistogram_lock) != 0) {
          count +=1;
          if ( (WarnOnStalledSpinLock > 0)
            && (count % WarnOnStalledSpinLock == 0)) {
            warning("JNIHistogram_lock seems to be stalled");
*** 3231,3241 ****
  static bool initializeDirectBufferSupport(JNIEnv* env, JavaThread* thread) {
    if (directBufferSupportInitializeFailed) {
      return false;
    }
  
!   if (Atomic::cmpxchg(1, &directBufferSupportInitializeStarted, 0) == 0) {
      if (!lookupDirectBufferClasses(env)) {
        directBufferSupportInitializeFailed = 1;
        return false;
      }
  
--- 3231,3241 ----
  static bool initializeDirectBufferSupport(JNIEnv* env, JavaThread* thread) {
    if (directBufferSupportInitializeFailed) {
      return false;
    }
  
!   if (Atomic::cmpxchg(&directBufferSupportInitializeStarted, 0, 1) == 0) {
      if (!lookupDirectBufferClasses(env)) {
        directBufferSupportInitializeFailed = 1;
        return false;
      }
  
*** 3687,3697 ****
  void copy_jni_function_table(const struct JNINativeInterface_ *new_jni_NativeInterface) {
    assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
    intptr_t *a = (intptr_t *) jni_functions();
    intptr_t *b = (intptr_t *) new_jni_NativeInterface;
    for (uint i=0; i <  sizeof(struct JNINativeInterface_)/sizeof(void *); i++) {
!     Atomic::store(*b++, a++);
    }
  }
  
  void quicken_jni_functions() {
    // Replace Get<Primitive>Field with fast versions
--- 3687,3697 ----
  void copy_jni_function_table(const struct JNINativeInterface_ *new_jni_NativeInterface) {
    assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
    intptr_t *a = (intptr_t *) jni_functions();
    intptr_t *b = (intptr_t *) new_jni_NativeInterface;
    for (uint i=0; i <  sizeof(struct JNINativeInterface_)/sizeof(void *); i++) {
!     Atomic::store(a++, *b++);
    }
  }
  
  void quicken_jni_functions() {
    // Replace Get<Primitive>Field with fast versions
*** 3809,3821 ****
    // but __sync_lock_test_and_set is not guaranteed to do what we want
    // on all architectures.  So we check it works before relying on it.
  #if defined(ZERO) && defined(ASSERT)
    {
      jint a = 0xcafebabe;
!     jint b = Atomic::xchg((jint) 0xdeadbeef, &a);
      void *c = &a;
!     void *d = Atomic::xchg(&b, &c);
      assert(a == (jint) 0xdeadbeef && b == (jint) 0xcafebabe, "Atomic::xchg() works");
      assert(c == &b && d == &a, "Atomic::xchg() works");
    }
  #endif // ZERO && ASSERT
  
--- 3809,3821 ----
    // but __sync_lock_test_and_set is not guaranteed to do what we want
    // on all architectures.  So we check it works before relying on it.
  #if defined(ZERO) && defined(ASSERT)
    {
      jint a = 0xcafebabe;
!     jint b = Atomic::xchg(&a, (jint) 0xdeadbeef);
      void *c = &a;
!     void *d = Atomic::xchg(&c, &b);
      assert(a == (jint) 0xdeadbeef && b == (jint) 0xcafebabe, "Atomic::xchg() works");
      assert(c == &b && d == &a, "Atomic::xchg() works");
    }
  #endif // ZERO && ASSERT
  
*** 3827,3840 ****
    // one thread can call this method at a time
  
    // We use Atomic::xchg rather than Atomic::add/dec since on some platforms
    // the add/dec implementations are dependent on whether we are running
    // on a multiprocessor Atomic::xchg does not have this problem.
!   if (Atomic::xchg(1, &vm_created) == 1) {
      return JNI_EEXIST;   // already created, or create attempt in progress
    }
!   if (Atomic::xchg(0, &safe_to_recreate_vm) == 0) {
      return JNI_ERR;  // someone tried and failed and retry not allowed.
    }
  
    assert(vm_created == 1, "vm_created is true during the creation");
  
--- 3827,3840 ----
    // one thread can call this method at a time
  
    // We use Atomic::xchg rather than Atomic::add/dec since on some platforms
    // the add/dec implementations are dependent on whether we are running
    // on a multiprocessor Atomic::xchg does not have this problem.
!   if (Atomic::xchg(&vm_created, 1) == 1) {
      return JNI_EEXIST;   // already created, or create attempt in progress
    }
!   if (Atomic::xchg(&safe_to_recreate_vm, 0) == 0) {
      return JNI_ERR;  // someone tried and failed and retry not allowed.
    }
  
    assert(vm_created == 1, "vm_created is true during the creation");