Ejemplo n.º 1
0
  @Override
  public void init(int blockId, String metainf) {
    readSet.clear();
    writeSet.clear();

    // Lock according to the transaction irrevocable state
    if (irrevocableState) irrevocableAccessLock.writeLock().lock();
    else irrevocableAccessLock.readLock().lock();

    endTime = clock.get();
    startTime.set(endTime);
    status.set(((status.get() + (1 << STATUS_BITS)) & ~STATUS_MASK) | TX_ACTIVE);
    if (RO_HINT) {
      atomicBlockId = blockId;
      readWriteHint = readWriteMarkers.get(atomicBlockId);
    }
    attempts++;
    vr = (VR_THRESHOLD > 0 && VR_THRESHOLD <= attempts);
  }
Ejemplo n.º 2
0
  private void onWriteAccess(Object obj, long field, Object value, Type type) {
    if (!readWriteHint) {
      // Change hint to read-write
      readWriteMarkers.insert(atomicBlockId, true);
      throw READ_ONLY_FAILURE_EXCEPTION;
    }

    int hash = LockTable.hash(obj, field);
    // Lock entry in write mode (might throw an exception)
    long timestamp = LockTable.lock(this, hash, id, true);

    synchronized (writeSet) {
      // Mutual exclusion on write set to allow other transaction to drop locks
      if ((status.get() & STATUS_MASK) != TX_ACTIVE) {
        // We have been killed
        if (timestamp >= 0) {
          // Drop lock we just acquired (not in write set)
          LockTable.setAndReleaseLock(hash, timestamp);
        }
        // Abort
        throw KILLED_EXCEPTION;
      }
      if (timestamp < 0) {
        // We already own that lock
        writeSet.appendWrite(hash, obj, field, value, type);
      } else {
        // Add to write set
        if (timestamp > endTime) {
          // Handle write-after-read
          if (readSet.contains(obj, field)) {
            // Abort
            LockTable.setAndReleaseLock(hash, timestamp);
            throw WRITE_FAILURE_EXCEPTION;
          }
          // We delay validation until later (although we could already validate once here)
        }
        // Add to write set
        writeSet.addWrite(hash, obj, field, value, type, timestamp);
      }
    }
  }