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/*
* 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.spark.memory;
import java.io.IOException;
import org.apache.spark.unsafe.array.LongArray;
import org.apache.spark.unsafe.memory.MemoryBlock;
/**
* A memory consumer of {@link TaskMemoryManager} that supports spilling.
*
* Note: this only supports allocation / spilling of Tungsten memory.
*/
public abstract class MemoryConsumer {
protected final TaskMemoryManager taskMemoryManager;
private final long pageSize;
private final MemoryMode mode;
protected long used;
protected MemoryConsumer(TaskMemoryManager taskMemoryManager, long pageSize, MemoryMode mode) {
this.taskMemoryManager = taskMemoryManager;
this.pageSize = pageSize;
this.mode = mode;
}
protected MemoryConsumer(TaskMemoryManager taskMemoryManager) {
this(taskMemoryManager, taskMemoryManager.pageSizeBytes(), MemoryMode.ON_HEAP);
}
/**
* Returns the memory mode, {@link MemoryMode#ON_HEAP} or {@link MemoryMode#OFF_HEAP}.
*/
public MemoryMode getMode() {
return mode;
}
/**
* Returns the size of used memory in bytes.
*/
protected long getUsed() {
return used;
}
/**
* Force spill during building.
*
* For testing.
*/
public void spill() throws IOException {
spill(Long.MAX_VALUE, this);
}
/**
* Spill some data to disk to release memory, which will be called by TaskMemoryManager
* when there is not enough memory for the task.
*
* This should be implemented by subclass.
*
* Note: In order to avoid possible deadlock, should not call acquireMemory() from spill().
*
* Note: today, this only frees Tungsten-managed pages.
*
* @param size the amount of memory should be released
* @param trigger the MemoryConsumer that trigger this spilling
* @return the amount of released memory in bytes
* @throws IOException
*/
public abstract long spill(long size, MemoryConsumer trigger) throws IOException;
/**
* Allocates a LongArray of `size`.
*/
public LongArray allocateArray(long size) {
long required = size * 8L;
MemoryBlock page = taskMemoryManager.allocatePage(required, this);
if (page == null || page.size() < required) {
long got = 0;
if (page != null) {
got = page.size();
taskMemoryManager.freePage(page, this);
}
taskMemoryManager.showMemoryUsage();
throw new OutOfMemoryError("Unable to acquire " + required + " bytes of memory, got " + got);
}
used += required;
return new LongArray(page);
}
/**
* Frees a LongArray.
*/
public void freeArray(LongArray array) {
freePage(array.memoryBlock());
}
/**
* Allocate a memory block with at least `required` bytes.
*
* Throws IOException if there is not enough memory.
*
* @throws OutOfMemoryError
*/
protected MemoryBlock allocatePage(long required) {
MemoryBlock page = taskMemoryManager.allocatePage(Math.max(pageSize, required), this);
if (page == null || page.size() < required) {
long got = 0;
if (page != null) {
got = page.size();
taskMemoryManager.freePage(page, this);
}
taskMemoryManager.showMemoryUsage();
throw new OutOfMemoryError("Unable to acquire " + required + " bytes of memory, got " + got);
}
used += page.size();
return page;
}
/**
* Free a memory block.
*/
protected void freePage(MemoryBlock page) {
used -= page.size();
taskMemoryManager.freePage(page, this);
}
/**
* Allocates memory of `size`.
*/
public long acquireMemory(long size) {
long granted = taskMemoryManager.acquireExecutionMemory(size, this);
used += granted;
return granted;
}
/**
* Release N bytes of memory.
*/
public void freeMemory(long size) {
taskMemoryManager.releaseExecutionMemory(size, this);
used -= size;
}
}
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