小编Gab*_*ini的帖子

我正在ReaderWriterLockSlim用来保护一些操作.我想赞成读者而不是作家,这样当读者长时间持有锁并且作家试图获得写锁时,未来的读者也不会被作者的尝试所阻挡(如果是这样的话会发生这种情况.作家被封锁了lock.EnterWriteLock()).

为此,我虽然编写器可以TryEnterWriteLock在循环中使用短暂的超时,以便后续的读者仍然能够获得读锁定而编写者不能.然而,令我惊讶的是,我发现一个不成功的呼叫TryEnterWriteLock改变了锁的状态,无论如何阻止了未来的读者.概念证明代码:

System.Threading.ReaderWriterLockSlim myLock = new System.Threading.ReaderWriterLockSlim(System.Threading.LockRecursionPolicy.NoRecursion);

System.Threading.Thread t1 = new System.Threading.Thread(() =>
{
    Console.WriteLine("T1:{0}: entering read lock...", DateTime.Now);
    myLock.EnterReadLock();
    Console.WriteLine("T1:{0}: ...entered read lock.", DateTime.Now);

    System.Threading.Thread.Sleep(10000);
});

System.Threading.Thread t2 = new System.Threading.Thread(() =>
{
    System.Threading.Thread.Sleep(1000);

    while (true)
    {
        Console.WriteLine("T2:{0}: try-entering write lock...", DateTime.Now);
        bool result = myLock.TryEnterWriteLock(TimeSpan.FromMilliseconds(1500));
        Console.WriteLine("T2:{0}: ...try-entered write lock, result={1}.", DateTime.Now, result);

        if (result)
        {
            // Got it!
            break;
        }

        System.Threading.Thread.Yield();
    }

    System.Threading.Thread.Sleep(9000);
});

System.Threading.Thread t3 = new System.Threading.Thread(() => …