/** {@inheritDoc} */
  @Override
  public void start() throws IgniteCheckedException {
    IpcSharedMemoryNativeLoader.load(log);

    pid = IpcSharedMemoryUtils.pid();

    if (pid == -1) throw new IpcEndpointBindException("Failed to get PID of the current process.");

    if (size <= 0) throw new IpcEndpointBindException("Space size should be positive: " + size);

    String tokDirPath = this.tokDirPath;

    if (F.isEmpty(tokDirPath)) throw new IpcEndpointBindException("Token directory path is empty.");

    tokDirPath = tokDirPath + '/' + locNodeId.toString() + '-' + IpcSharedMemoryUtils.pid();

    tokDir = U.resolveWorkDirectory(tokDirPath, false);

    if (port <= 0 || port >= 0xffff)
      throw new IpcEndpointBindException("Port value is illegal: " + port);

    try {
      srvSock = new ServerSocket();

      // Always bind to loopback.
      srvSock.bind(new InetSocketAddress("127.0.0.1", port));
    } catch (IOException e) {
      // Although empty socket constructor never throws exception, close it just in case.
      U.closeQuiet(srvSock);

      throw new IpcEndpointBindException(
          "Failed to bind shared memory IPC endpoint (is port already " + "in use?): " + port, e);
    }

    gcWorker = new GcWorker(gridName, "ipc-shmem-gc", log);

    new IgniteThread(gcWorker).start();

    if (log.isInfoEnabled())
      log.info(
          "IPC shared memory server endpoint started [port="
              + port
              + ", tokDir="
              + tokDir.getAbsolutePath()
              + ']');
  }
  /**
   * Updates value for single partition.
   *
   * @param p Partition.
   * @param nodeId Node ID.
   * @param state State.
   * @param updateSeq Update sequence.
   */
  @SuppressWarnings({"MismatchedQueryAndUpdateOfCollection"})
  private void updateLocal(int p, UUID nodeId, GridDhtPartitionState state, long updateSeq) {
    assert lock.isWriteLockedByCurrentThread();
    assert nodeId.equals(cctx.nodeId());

    // In case if node joins, get topology at the time of joining node.
    ClusterNode oldest = CU.oldestAliveCacheServerNode(cctx.shared(), topVer);

    assert oldest != null;

    // If this node became the oldest node.
    if (oldest.id().equals(cctx.nodeId())) {
      long seq = node2part.updateSequence();

      if (seq != updateSeq) {
        if (seq > updateSeq) {
          if (this.updateSeq.get() < seq) {
            // Update global counter if necessary.
            boolean b = this.updateSeq.compareAndSet(this.updateSeq.get(), seq + 1);

            assert b
                : "Invalid update sequence [updateSeq="
                    + updateSeq
                    + ", seq="
                    + seq
                    + ", curUpdateSeq="
                    + this.updateSeq.get()
                    + ", node2part="
                    + node2part.toFullString()
                    + ']';

            updateSeq = seq + 1;
          } else updateSeq = seq;
        }

        node2part.updateSequence(updateSeq);
      }
    }

    GridDhtPartitionMap map = node2part.get(nodeId);

    if (map == null)
      node2part.put(
          nodeId,
          map =
              new GridDhtPartitionMap(
                  nodeId,
                  updateSeq,
                  Collections.<Integer, GridDhtPartitionState>emptyMap(),
                  false));

    map.updateSequence(updateSeq);

    map.put(p, state);

    Set<UUID> ids = part2node.get(p);

    if (ids == null) part2node.put(p, ids = U.newHashSet(3));

    ids.add(nodeId);
  }
  /**
   * @param updateSeq Update sequence.
   * @return Checks if any of the local partitions need to be evicted.
   */
  private boolean checkEvictions(long updateSeq) {
    assert lock.isWriteLockedByCurrentThread();

    boolean changed = false;

    UUID locId = cctx.nodeId();

    for (GridDhtLocalPartition part : locParts.values()) {
      GridDhtPartitionState state = part.state();

      if (state.active()) {
        int p = part.id();

        List<ClusterNode> affNodes = cctx.affinity().nodes(p, topVer);

        if (!affNodes.contains(cctx.localNode())) {
          Collection<UUID> nodeIds = F.nodeIds(nodes(p, topVer, OWNING));

          // If all affinity nodes are owners, then evict partition from local node.
          if (nodeIds.containsAll(F.nodeIds(affNodes))) {
            part.rent(false);

            updateLocal(part.id(), locId, part.state(), updateSeq);

            changed = true;

            if (log.isDebugEnabled())
              log.debug("Evicted local partition (all affinity nodes are owners): " + part);
          } else {
            int ownerCnt = nodeIds.size();
            int affCnt = affNodes.size();

            if (ownerCnt > affCnt) {
              List<ClusterNode> sorted = new ArrayList<>(cctx.discovery().nodes(nodeIds));

              // Sort by node orders in ascending order.
              Collections.sort(sorted, CU.nodeComparator(true));

              int diff = sorted.size() - affCnt;

              for (int i = 0; i < diff; i++) {
                ClusterNode n = sorted.get(i);

                if (locId.equals(n.id())) {
                  part.rent(false);

                  updateLocal(part.id(), locId, part.state(), updateSeq);

                  changed = true;

                  if (log.isDebugEnabled())
                    log.debug(
                        "Evicted local partition (this node is oldest non-affinity node): " + part);

                  break;
                }
              }
            }
          }
        }
      }
    }

    return changed;
  }