shuzirra commented on a change in pull request #3430: URL: https://github.com/apache/hadoop/pull/3430#discussion_r712201581
########## File path: hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/AbstractCSQueueUsageTracker.java ########## @@ -0,0 +1,78 @@ +/** + * 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.yarn.server.resourcemanager.scheduler.capacity; + +import org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueResourceQuotas; +import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceUsage; + +public class AbstractCSQueueUsageTracker { + private final CSQueueMetrics metrics; + private volatile int numContainers; + + /** + * The timestamp of the last submitted application to this queue. + * Only applies to dynamic queues. + */ + private long lastSubmittedTimestamp; + + /** + * Tracks resource usage by label like used-resource / pending-resource. + */ + private volatile ResourceUsage queueUsage; + + private final QueueResourceQuotas queueResourceQuotas; + + public AbstractCSQueueUsageTracker(CSQueueMetrics metrics) { + this.metrics = metrics; + this.queueUsage = new ResourceUsage(); + this.queueResourceQuotas = new QueueResourceQuotas(); + } + + public int getNumContainers() { + return numContainers; + } + + public synchronized void increaseNumContainers() { + numContainers++; + } + + public synchronized void decreaseNumContainers() { Review comment: I don't see any issue with the synchronization, if this object needs to be thread safe, then we need to guarantee it on the object level, not hoping for other objects to use it in a thread safe only way. However keeping the field az volatile AND omitting the synchronization is actually a mistake. This class does NOT provide a proper way of incrementing the field, which means if it is used in a non-thread safe environment (volatile suggests that, since volatile does not make any sense in a thread safe environment), then the increment might fail. Hence the spotbug warning. So I'd strongly suggest to keep the synchronized it's not much overhead if we the methods are already invoked in threadsafe way, but a good guard if they are not. Also I'd omit volatile since value is only accessible via a getter, so outer methods won't benefit from the keyword, and internally we don't really use the variables (only to increase / decrease it in a volatile incompatible way). -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
