supermem613 commented on code in PR #5439: URL: https://github.com/apache/incubator-gluten/pull/5439#discussion_r1570827513
########## gluten-core/src/main/java/org/apache/gluten/memory/memtarget/spark/DynamicOffHeapSizingPolicyChecker.java: ########## @@ -0,0 +1,71 @@ +/* + * 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.gluten.memory.memtarget.spark; + +import org.apache.gluten.GlutenConfig; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.concurrent.atomic.AtomicLong; + +public final class DynamicOffHeapSizingPolicyChecker { + private static final Logger LOG = + LoggerFactory.getLogger(DynamicOffHeapSizingPolicyChecker.class); + private final long maxOnHeapMemoryInBytes = GlutenConfig.getConf().onHeapMemorySize(); + private final AtomicLong usedOffHeapBytes = new AtomicLong(); + + DynamicOffHeapSizingPolicyChecker() {} + + public boolean canBorrow(long size) { + if (size == 0) { + return true; + } + + long totalMemory = Runtime.getRuntime().totalMemory(); + long freeMemory = Runtime.getRuntime().freeMemory(); + long usedOnHeapBytes = (totalMemory - freeMemory); Review Comment: As per https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/lang/Runtime.html, totalMemory is the "the total amount of memory currently available for current and future objects, measured in bytes", i.e., the on-heap size set for Spark via spark.executor.memory in our case. freeMemory is the "an approximation to the total amount of memory currently available for future allocated objects", i.e., memory NOT currently in use by Java objects. In this calculation if the on-heap was set to 10GB and 5GB is unused by any Java objects, usedOnHeapBytes would give us 5GB. The JVM memory footprint in this case is 10GB. With the calculations above, we would allow up to 5GB of memory to be used for off-heap. Does that help? -- 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]
