// to indicate we haven't sufficiently unlocked lockers to avoid deadlocks.
	//
	// Caller may use this as an indication to call again.
	return !checkFailedUnlocks(*locks, tolerance)
}

// Unlock unlocks the write lock.
//
// It is a run-time error if dm is not locked on entry to Unlock.
func (dm *DRWMutex) Unlock(ctx context.Context) {
	dm.m.Lock()
	dm.cancelRefresh()
	dm.m.Unlock()

 *
 * <ul>
 *   <li>for an unnested {@code lock()} and {@code unlock()}, a cycle detecting lock takes 38ns as
 *       opposed to the 24ns taken by a plain lock.
 *   <li>for nested locking, the cost increases with the depth of the nesting:
 *       <ul>
 *         <li>2 levels: average of 64ns per lock()/unlock()
 *         <li>3 levels: average of 77ns per lock()/unlock()
 *         <li>4 levels: average of 99ns per lock()/unlock()

call <i>n</i> of <code>l.Unlock()</code> is synchronized before call <i>m</i> of <code>l.Lock()</code> returns.
</p>

<p>
This program:
</p>

<pre>
var l sync.Mutex
var a string

func f() {
	a = "hello, world"
	l.Unlock()
}

func main() {
	l.Lock()
	go f()
	l.Lock()
	print(a)
}
</pre>

	}
	if m.subroute != nil {
		msg.Flags |= FlagSubroute
	}
	ch := make(chan Response, 1)
	m.respMu.Lock()
	if m.closed {
		m.respMu.Unlock()
		return nil, ErrDisconnected
	}
	m.respWait = ch
	m.respMu.Unlock()
	ctx := m.ctx

	// Add deadline if none.
	if msg.DeadlineMS == 0 {
		msg.DeadlineMS = uint32(defaultSingleRequestTimeout / time.Millisecond)

    Lock lockB = factory.newReentrantLock(OtherOrder.SECOND);

    lockA.lock();
    lockA.lock();
    lockB.lock();
    lockB.lock();
    lockA.unlock();
    lockA.unlock();
    lockB.unlock();
    lockB.unlock();
  }

  public void testExplicitOrdering_acquiringMultipleLocksWithSameRank() {
    CycleDetectingLockFactory.WithExplicitOrdering<OtherOrder> factory =

    Lock lockB = factory.newReentrantLock(OtherOrder.SECOND);

    lockA.lock();
    lockA.lock();
    lockB.lock();
    lockB.lock();
    lockA.unlock();
    lockA.unlock();
    lockB.unlock();
    lockB.unlock();
  }

  public void testExplicitOrdering_acquiringMultipleLocksWithSameRank() {
    CycleDetectingLockFactory.WithExplicitOrdering<OtherOrder> factory =

	go func() {
		select {
		case <-ctx.Done():
			r.CloseWithError(ctx.Err())
		}
	}()
	return r
}

func (r *RingBuffer) setErr(err error, locked bool) error {
	if !locked {
		r.mu.Lock()
		defer r.mu.Unlock()
	}
	if r.err != nil && r.err != io.EOF {
		return r.err
	}

	switch err {
	// Internal errors are transient

	dm.Unlock(context.Background())
}

func TestSimpleLockUnlockMultipleTimes(t *testing.T) {
	dm := NewDRWMutex(ds, "test")

	dm.Lock(id, source)
	time.Sleep(time.Duration(10+(rand.Float32()*50)) * time.Millisecond)
	dm.Unlock(context.Background())

	dm.Lock(id, source)
	time.Sleep(time.Duration(10+(rand.Float32()*50)) * time.Millisecond)
	dm.Unlock(context.Background())

	dm.Lock(id, source)

	return concat(s, strconv.Itoa(idx))
}

func (l *localLocker) Unlock(_ context.Context, args dsync.LockArgs) (reply bool, err error) {
	if len(args.Resources) > maxDeleteList {
		return false, fmt.Errorf("internal error: localLocker.Unlock called with more than %d resources", maxDeleteList)
	}

	l.mutex.Lock()
	defer l.mutex.Unlock()
	err = nil

	for _, resource := range args.Resources {

// from a placeholder node "arg_tensor_enqueue_<tensor_id>".
//
// `tensor` is still owned by the caller. This call will be blocked if the queue
// has reached its capacity, and will be unblocked when the queued tensors again
// drop below the capacity due to dequeuing.
//
// Tensors are dequeued via the corresponding TF dequeue op.
// TODO(hongm): Add support for `timeout_ms`.