azagrebin commented on a change in pull request #9693: [FLINK-13984] Separate on-heap and off-heap managed memory pools URL: https://github.com/apache/flink/pull/9693#discussion_r336880767
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/util/KeyedBudgetManager.java ########## @@ -0,0 +1,238 @@ +/* + * 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.util; + +import org.apache.flink.types.Either; +import org.apache.flink.util.Preconditions; + +import javax.annotation.concurrent.GuardedBy; +import javax.annotation.concurrent.ThreadSafe; + +import java.util.Collections; +import java.util.HashMap; +import java.util.Map; +import java.util.Map.Entry; + +/** + * Manages {@code long} available budget per key (allocation/release). + * + * <p>This manager gets a certain maximum {@code long} budget per key. + * Users can allocate some budget for some key and release it later. + * The manager keeps track of allocated/released budget and prevents from over-allocating. + * + * <p>There is also a paged type of allocation where a certain number of pages can be allocated from a set of keys. + * The page has its budget size. The manager allocates randomly from all keys of a given set. + * At the end, sum of pages allocated from each key is either requested number of pages or none. + * Only integer number of pages are allocated from each key respecting its available budget (no page spans two or more keys) + * or nothing is allocated reporting the maximum number of pages which could be allocated per each given key at the moment. + * + * @param <K> type of the budget key + */ +@ThreadSafe +public class KeyedBudgetManager<K> { + private final Map<K, Long> maxBudgetByKey; + + private final long defaultPageSize; + + private final long totalNumberOfPages; + + @GuardedBy("lock") + private final Map<K, Long> availableBudgetByKey; + + private final Object lock = new Object(); + + public KeyedBudgetManager(Map<K, Long> maxBudgetByKey, long defaultPageSize) { + Preconditions.checkNotNull(maxBudgetByKey); + Preconditions.checkArgument(defaultPageSize > 0L, "The default page size has to be greater than zero"); + + this.maxBudgetByKey = new HashMap<>(maxBudgetByKey); + this.availableBudgetByKey = new HashMap<>(maxBudgetByKey); + this.defaultPageSize = defaultPageSize; + this.totalNumberOfPages = calculateTotalNumberOfPages(maxBudgetByKey, defaultPageSize); + } + + public long getDefaultPageSize() { + return defaultPageSize; + } + + /** + * Tries to acquire budget for a given key. + * + * <p>No budget is acquired if it was not possible to fully acquire the requested budget. + * + * @param key the key to acquire budget from + * @param size the size of budget to acquire from the given key + * @return the fully acquired budget for the key or max possible budget to acquire + * if it was not possible to acquire the requested budget. + */ + public long acquireBudgetForKey(K key, long size) { + Preconditions.checkNotNull(key); + Either<Map<K, Long>, Long> result = acquirePagedBudgetForKeys(Collections.singletonList(key), size, 1L); + return result.isLeft() ? result.left().get(key) : result.right(); + } + + /** + * Tries to acquire budget for given keys which equals to the number of pages times default page size. + * + * <p>See also {@link #acquirePagedBudgetForKeys(Iterable, long, long)} + */ + public Either<Map<K, Long>, Long> acquirePagedBudget(Iterable<K> keys, long numberOfPages) { + return acquirePagedBudgetForKeys(keys, numberOfPages, defaultPageSize); + } + + /** + * Tries to acquire budget which equals to the number of pages times page size. + * + * <p>The budget will be acquired only from the given keys. Only integer number of pages will be acquired from each key. + * If the next page does not fit into the available budget of some key, it will try to be acquired from another key. + * The acquisition is successful if the acquired number of pages for each key sums up to the requested number of pages. + * The function does not make any preference about which keys from the given keys to acquire from. + * + * @param keys the keys to acquire budget from + * @param numberOfPages the total number of pages to acquire from the given keys + * @param pageSize the size of budget to acquire per page + * @return the acquired number of pages for each key if the acquisition is successful (either left) or + * the total number of pages which were available for the given keys (either right). + */ + Either<Map<K, Long>, Long> acquirePagedBudgetForKeys(Iterable<K> keys, long numberOfPages, long pageSize) { + Preconditions.checkNotNull(keys); + Preconditions.checkArgument(numberOfPages >= 0L, "The requested number of pages has to be positive"); + Preconditions.checkArgument(pageSize > 0L, "The page size has to be greater than zero"); + + synchronized (lock) { + long totalPossiblePages = 0L; + Map<K, Long> pagesToReserveByKey = new HashMap<>(); + for (K key : keys) { + long currentKeyBudget = availableBudgetByKey.getOrDefault(key, 0L); + long currentKeyPages = currentKeyBudget / pageSize; + if (totalPossiblePages + currentKeyPages >= numberOfPages) { + pagesToReserveByKey.put(key, numberOfPages - totalPossiblePages); + totalPossiblePages = numberOfPages; + break; + } else if (currentKeyPages > 0L) { + pagesToReserveByKey.put(key, currentKeyPages); + totalPossiblePages += currentKeyPages; + } + } + boolean possibleToAcquire = totalPossiblePages == numberOfPages; + if (possibleToAcquire) { + for (Entry<K, Long> pagesToReserveForKey : pagesToReserveByKey.entrySet()) { + //noinspection ConstantConditions + availableBudgetByKey.compute( + pagesToReserveForKey.getKey(), + (k, v) -> v - (pagesToReserveForKey.getValue() * pageSize)); + } + } + return possibleToAcquire ? Either.Left(pagesToReserveByKey) : Either.Right(totalPossiblePages); + } + } + + public void releasePageForKey(K key) { + releaseBudgetForKey(key, defaultPageSize); + } Review comment: True, I could add a test. The reason, I have not added, is that this is just a shorthand method as also others. The value of this kind of tests is probably not so big comparing to the effort and maintaining them. It is also an internal component, in worst un-probable case, tests for other components using them will fail. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
