| /** |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.hadoop.hdfs.server.balancer; |
| |
| import java.util.ArrayList; |
| import java.util.HashMap; |
| import java.util.List; |
| import java.util.Map; |
| |
| import org.apache.hadoop.hdfs.protocol.Block; |
| import org.apache.hadoop.util.Time; |
| |
| /** |
| * This window makes sure to keep blocks that have been moved within a fixed |
| * time interval (default is 1.5 hour). Old window has blocks that are older; |
| * Current window has blocks that are more recent; Cleanup method triggers the |
| * check if blocks in the old window are more than the fixed time interval. If |
| * yes, purge the old window and then move blocks in current window to old |
| * window. |
| * |
| * @param <L> Location type |
| */ |
| public class MovedBlocks<L> { |
| /** A class for keeping track of a block and its locations */ |
| public static class Locations<L> { |
| private final Block block; // the block |
| /** The locations of the replicas of the block. */ |
| protected final List<L> locations = new ArrayList<L>(3); |
| |
| public Locations(Block block) { |
| this.block = block; |
| } |
| |
| /** clean block locations */ |
| public synchronized void clearLocations() { |
| locations.clear(); |
| } |
| |
| /** add a location */ |
| public synchronized void addLocation(L loc) { |
| if (!locations.contains(loc)) { |
| locations.add(loc); |
| } |
| } |
| |
| /** @return if the block is located on the given location. */ |
| public synchronized boolean isLocatedOn(L loc) { |
| return locations.contains(loc); |
| } |
| |
| /** @return its locations */ |
| public synchronized List<L> getLocations() { |
| return locations; |
| } |
| |
| /* @return the block */ |
| public Block getBlock() { |
| return block; |
| } |
| |
| /* Return the length of the block */ |
| public long getNumBytes() { |
| return block.getNumBytes(); |
| } |
| |
| @Override |
| public String toString() { |
| return block + " size=" + getNumBytes(); |
| } |
| } |
| |
| private static final int CUR_WIN = 0; |
| private static final int OLD_WIN = 1; |
| private static final int NUM_WINS = 2; |
| |
| private final long winTimeInterval; |
| private long lastCleanupTime = Time.monotonicNow(); |
| private final List<Map<Block, Locations<L>>> movedBlocks |
| = new ArrayList<Map<Block, Locations<L>>>(NUM_WINS); |
| |
| /** initialize the moved blocks collection */ |
| public MovedBlocks(long winTimeInterval) { |
| this.winTimeInterval = winTimeInterval; |
| movedBlocks.add(newMap()); |
| movedBlocks.add(newMap()); |
| } |
| |
| private Map<Block, Locations<L>> newMap() { |
| return new HashMap<Block, Locations<L>>(); |
| } |
| |
| /** add a block thus marking a block to be moved */ |
| public synchronized void put(Locations<L> block) { |
| movedBlocks.get(CUR_WIN).put(block.getBlock(), block); |
| } |
| |
| /** @return if a block is marked as moved */ |
| public synchronized boolean contains(Block block) { |
| return movedBlocks.get(CUR_WIN).containsKey(block) || |
| movedBlocks.get(OLD_WIN).containsKey(block); |
| } |
| |
| /** remove old blocks */ |
| public synchronized void cleanup() { |
| long curTime = Time.monotonicNow(); |
| // check if old win is older than winWidth |
| if (lastCleanupTime + winTimeInterval <= curTime) { |
| // purge the old window |
| movedBlocks.set(OLD_WIN, movedBlocks.get(CUR_WIN)); |
| movedBlocks.set(CUR_WIN, newMap()); |
| lastCleanupTime = curTime; |
| } |
| } |
| } |