Thesharing commented on a change in pull request #16498: URL: https://github.com/apache/flink/pull/16498#discussion_r677298097
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/blob/BlobCacheSizeTracker.java ########## @@ -0,0 +1,177 @@ +/* + * 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.flink.runtime.blob; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.api.common.JobID; +import org.apache.flink.api.java.tuple.Tuple2; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import javax.annotation.Nullable; +import javax.annotation.concurrent.GuardedBy; + +import java.util.ArrayList; +import java.util.Collections; +import java.util.HashMap; +import java.util.HashSet; +import java.util.LinkedHashMap; +import java.util.List; +import java.util.Map; +import java.util.Set; + +import static org.apache.flink.util.Preconditions.checkArgument; +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * BlobCacheSizeTracker uses {@link LinkedHashMap} to maintain the LRU order for the files in the + * cache. When new files are intended to be put into cache, {@code checkLimit} is called to query + * the files should be removed. This tracker maintains a lock to avoid concurrent modification. To + * avoid the deadlock, make sure that hold the READ/WRITE lock in {@link PermanentBlobCache} first + * and then hold the lock here. + */ +public class BlobCacheSizeTracker { + + private static final Logger LOG = LoggerFactory.getLogger(BlobCacheSizeTracker.class); + + private static final int INITIAL_SIZE = 10_000; + + private final Object lock = new Object(); + + protected final long sizeLimit; + + @GuardedBy("lock") + private long total; + + @GuardedBy("lock") + private final LinkedHashMap<Tuple2<JobID, BlobKey>, Long> caches; + + @GuardedBy("lock") + protected final HashMap<JobID, Set<BlobKey>> blobKeyByJob; + + public BlobCacheSizeTracker(long sizeLimit) { + this.sizeLimit = sizeLimit; + this.total = 0L; + this.caches = new LinkedHashMap<>(INITIAL_SIZE, 0.75F, true); + this.blobKeyByJob = new HashMap<>(); + } + + /** + * Check the size limit and return the files to delete. + * + * @param size size of the target file intended to put into cache + * @return list of files to delete before saving the target file + */ + public List<Tuple2<JobID, BlobKey>> checkLimit(long size) { + checkArgument(size >= 0); + + synchronized (lock) { + List<Tuple2<JobID, BlobKey>> blobsToDelete = new ArrayList<>(); + + long current = total; + + for (Map.Entry<Tuple2<JobID, BlobKey>, Long> entry : caches.entrySet()) { + if (current + size > sizeLimit) { + blobsToDelete.add(entry.getKey()); + current -= entry.getValue(); + } + } + + return blobsToDelete; + } + } + + /** Register the target file to the tracker. */ + public void track(@Nullable JobID jobId, BlobKey blobKey, long size) { + checkNotNull(blobKey); + checkArgument(size >= 0); + + synchronized (lock) { + caches.put(Tuple2.of(jobId, blobKey), size); Review comment: Alright. If duplicated, new comers will be ignored. Warning will output. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
