C++ oop::release_set_mark方法代码示例

static BiasedLocking::Condition revoke_bias(oop obj, bool allow_rebias, bool is_bulk, JavaThread* requesting_thread) {
  markOop mark = obj->mark();
  if (!mark->has_bias_pattern()) {
    if (TraceBiasedLocking) {
      ResourceMark rm;
      tty->print_cr("  (Skipping revocation of object of type %s because it's no longer biased)",
                    obj->klass()->external_name());
    }
    return BiasedLocking::NOT_BIASED;
  }

  uint age = mark->age();
  markOop   biased_prototype = markOopDesc::biased_locking_prototype()->set_age(age);
  markOop unbiased_prototype = markOopDesc::prototype()->set_age(age);

  if (TraceBiasedLocking && (Verbose || !is_bulk)) {
    ResourceMark rm;
    tty->print_cr("Revoking bias of object " INTPTR_FORMAT " , mark " INTPTR_FORMAT " , type %s , prototype header " INTPTR_FORMAT " , allow rebias %d , requesting thread " INTPTR_FORMAT,
                  p2i((void *)obj), (intptr_t) mark, obj->klass()->external_name(), (intptr_t) obj->klass()->prototype_header(), (allow_rebias ? 1 : 0), (intptr_t) requesting_thread);
  }

  JavaThread* biased_thread = mark->biased_locker();
  if (biased_thread == NULL) {
    // Object is anonymously biased. We can get here if, for
    // example, we revoke the bias due to an identity hash code
    // being computed for an object.
    if (!allow_rebias) {
      obj->set_mark(unbiased_prototype);
    }
    if (TraceBiasedLocking && (Verbose || !is_bulk)) {
      tty->print_cr("  Revoked bias of anonymously-biased object");
    }
    return BiasedLocking::BIAS_REVOKED;
  }

  // Handle case where the thread toward which the object was biased has exited
  bool thread_is_alive = false;
  if (requesting_thread == biased_thread) {
    thread_is_alive = true;
  } else {
    for (JavaThread* cur_thread = Threads::first(); cur_thread != NULL; cur_thread = cur_thread->next()) {
      if (cur_thread == biased_thread) {
        thread_is_alive = true;
        break;
      }
    }
  }
  if (!thread_is_alive) {
    if (allow_rebias) {
      obj->set_mark(biased_prototype);
    } else {
      obj->set_mark(unbiased_prototype);
    }
    if (TraceBiasedLocking && (Verbose || !is_bulk)) {
      tty->print_cr("  Revoked bias of object biased toward dead thread");
    }
    return BiasedLocking::BIAS_REVOKED;
  }

  // Thread owning bias is alive.
  // Check to see whether it currently owns the lock and, if so,
  // write down the needed displaced headers to the thread's stack.
  // Otherwise, restore the object's header either to the unlocked
  // or unbiased state.
  GrowableArray<MonitorInfo*>* cached_monitor_info = get_or_compute_monitor_info(biased_thread);
  BasicLock* highest_lock = NULL;
  for (int i = 0; i < cached_monitor_info->length(); i++) {
    MonitorInfo* mon_info = cached_monitor_info->at(i);
    if (mon_info->owner() == obj) {
      if (TraceBiasedLocking && Verbose) {
        tty->print_cr("   mon_info->owner (" PTR_FORMAT ") == obj (" PTR_FORMAT ")",
                      p2i((void *) mon_info->owner()),
                      p2i((void *) obj));
      }
      // Assume recursive case and fix up highest lock later
      markOop mark = markOopDesc::encode((BasicLock*) NULL);
      highest_lock = mon_info->lock();
      highest_lock->set_displaced_header(mark);
    } else {
      if (TraceBiasedLocking && Verbose) {
        tty->print_cr("   mon_info->owner (" PTR_FORMAT ") != obj (" PTR_FORMAT ")",
                      p2i((void *) mon_info->owner()),
                      p2i((void *) obj));
      }
    }
  }
  if (highest_lock != NULL) {
    // Fix up highest lock to contain displaced header and point
    // object at it
    highest_lock->set_displaced_header(unbiased_prototype);
    // Reset object header to point to displaced mark.
    // Must release storing the lock address for platforms without TSO
    // ordering (e.g. ppc).
    obj->release_set_mark(markOopDesc::encode(highest_lock));
    assert(!obj->mark()->has_bias_pattern(), "illegal mark state: stack lock used bias bit");
    if (TraceBiasedLocking && (Verbose || !is_bulk)) {
      tty->print_cr("  Revoked bias of currently-locked object");
    }
  } else {
    if (TraceBiasedLocking && (Verbose || !is_bulk)) {
//.........这里部分代码省略.........