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Issue #6974 - improvements & fixes to ByteBufferPool implementations (#…
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…7017)

- WebSocket should user server ByteBufferPool if possible
- fix various bugs ByteBufferPool implementations
- add heuristic for maxHeapMemory and maxDirectMemory
- Add dump for ByteBufferPools
- add LogArrayByteBufferPool that does exponential scaling of bucket size.
- ByteBufferPools should default to use maxMemory heuristic
- Add module jetty-bytebufferpool-logarithmic

Signed-off-by: Lachlan Roberts <lachlan@webtide.com>
Co-authored-by: Simone Bordet <simone.bordet@gmail.com>
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@lachlan-roberts @sbordet
lachlan-roberts and sbordet committed Nov 24, 2021
1 parent b365b3c commit c19921e
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Showing 12 changed files with 635 additions and 118 deletions.
34 changes: 31 additions & 3 deletions jetty-io/src/main/java/org/eclipse/jetty/io/AbstractByteBufferPool.java
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
import java.nio.ByteBuffer;
import java.util.concurrent.atomic.AtomicLong;
import java.util.function.Consumer;
import java.util.function.IntConsumer;

import org.eclipse.jetty.util.annotation.ManagedAttribute;
import org.eclipse.jetty.util.annotation.ManagedObject;
Expand All @@ -27,16 +28,24 @@ abstract class AbstractByteBufferPool implements ByteBufferPool
private final int _factor;
private final int _maxQueueLength;
private final long _maxHeapMemory;
private final AtomicLong _heapMemory = new AtomicLong();
private final long _maxDirectMemory;
private final AtomicLong _heapMemory = new AtomicLong();
private final AtomicLong _directMemory = new AtomicLong();

/**
* Creates a new ByteBufferPool with the given configuration.
*
* @param factor the capacity factor
* @param maxQueueLength the maximum ByteBuffer queue length
* @param maxHeapMemory the max heap memory in bytes, -1 for unlimited memory or 0 to use default heuristic.
* @param maxDirectMemory the max direct memory in bytes, -1 for unlimited memory or 0 to use default heuristic.
*/
protected AbstractByteBufferPool(int factor, int maxQueueLength, long maxHeapMemory, long maxDirectMemory)
{
_factor = factor <= 0 ? 1024 : factor;
_maxQueueLength = maxQueueLength;
_maxHeapMemory = maxHeapMemory;
_maxDirectMemory = maxDirectMemory;
_maxHeapMemory = (maxHeapMemory != 0) ? maxHeapMemory : Runtime.getRuntime().maxMemory() / 4;
_maxDirectMemory = (maxDirectMemory != 0) ? maxDirectMemory : Runtime.getRuntime().maxMemory() / 4;
}

protected int getCapacityFactor()
Expand All @@ -49,11 +58,13 @@ protected int getMaxQueueLength()
return _maxQueueLength;
}

@Deprecated
protected void decrementMemory(ByteBuffer buffer)
{
updateMemory(buffer, false);
}

@Deprecated
protected void incrementMemory(ByteBuffer buffer)
{
updateMemory(buffer, true);
Expand Down Expand Up @@ -90,12 +101,29 @@ public long getHeapMemory()
return getMemory(false);
}

@ManagedAttribute("The max num of bytes that can be retained from direct ByteBuffers")
public long getMaxDirectMemory()
{
return _maxDirectMemory;
}

@ManagedAttribute("The max num of bytes that can be retained from heap ByteBuffers")
public long getMaxHeapMemory()
{
return _maxHeapMemory;
}

public long getMemory(boolean direct)
{
AtomicLong memory = direct ? _directMemory : _heapMemory;
return memory.get();
}

IntConsumer updateMemory(boolean direct)
{
return (direct) ? _directMemory::addAndGet : _heapMemory::addAndGet;
}

@ManagedOperation(value = "Clears this ByteBufferPool", impact = "ACTION")
public void clear()
{
Expand Down
131 changes: 91 additions & 40 deletions jetty-io/src/main/java/org/eclipse/jetty/io/ArrayByteBufferPool.java
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Original file line number Diff line number Diff line change
Expand Up @@ -13,14 +13,19 @@

package org.eclipse.jetty.io;

import java.io.IOException;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.Objects;
import java.util.function.IntFunction;
import java.util.stream.Collectors;

import org.eclipse.jetty.util.BufferUtil;
import org.eclipse.jetty.util.annotation.ManagedAttribute;
import org.eclipse.jetty.util.annotation.ManagedObject;
import org.eclipse.jetty.util.component.Dumpable;
import org.eclipse.jetty.util.component.DumpableCollection;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

Expand All @@ -31,13 +36,15 @@
* 2048, and so on.</p>
*/
@ManagedObject
public class ArrayByteBufferPool extends AbstractByteBufferPool
public class ArrayByteBufferPool extends AbstractByteBufferPool implements Dumpable
{
private static final Logger LOG = LoggerFactory.getLogger(MappedByteBufferPool.class);

private final int _maxCapacity;
private final int _minCapacity;
private final ByteBufferPool.Bucket[] _direct;
private final ByteBufferPool.Bucket[] _indirect;
private boolean _detailedDump = false;

/**
* Creates a new ArrayByteBufferPool with a default configuration.
Expand All @@ -56,7 +63,7 @@ public ArrayByteBufferPool()
*/
public ArrayByteBufferPool(int minCapacity, int factor, int maxCapacity)
{
this(minCapacity, factor, maxCapacity, -1, -1, -1);
this(minCapacity, factor, maxCapacity, -1, 0, 0);
}

/**
Expand All @@ -69,7 +76,7 @@ public ArrayByteBufferPool(int minCapacity, int factor, int maxCapacity)
*/
public ArrayByteBufferPool(int minCapacity, int factor, int maxCapacity, int maxQueueLength)
{
this(minCapacity, factor, maxCapacity, maxQueueLength, -1, -1);
this(minCapacity, factor, maxCapacity, maxQueueLength, 0, 0);
}

/**
Expand All @@ -79,8 +86,8 @@ public ArrayByteBufferPool(int minCapacity, int factor, int maxCapacity, int max
* @param factor the capacity factor
* @param maxCapacity the maximum ByteBuffer capacity
* @param maxQueueLength the maximum ByteBuffer queue length
* @param maxHeapMemory the max heap memory in bytes
* @param maxDirectMemory the max direct memory in bytes
* @param maxHeapMemory the max heap memory in bytes, -1 for unlimited memory or 0 to use default heuristic.
* @param maxDirectMemory the max direct memory in bytes, -1 for unlimited memory or 0 to use default heuristic.
*/
public ArrayByteBufferPool(int minCapacity, int factor, int maxCapacity, int maxQueueLength, long maxHeapMemory, long maxDirectMemory)
{
Expand All @@ -93,24 +100,30 @@ public ArrayByteBufferPool(int minCapacity, int factor, int maxCapacity, int max
maxCapacity = 64 * 1024;
if ((maxCapacity % factor) != 0 || factor >= maxCapacity)
throw new IllegalArgumentException("The capacity factor must be a divisor of maxCapacity");
_maxCapacity = maxCapacity;
_minCapacity = minCapacity;

int length = maxCapacity / factor;
// Initialize all buckets in constructor and never modify the array again.
int length = bucketFor(maxCapacity);
_direct = new ByteBufferPool.Bucket[length];
_indirect = new ByteBufferPool.Bucket[length];
for (int i = 0; i < length; i++)
{
_direct[i] = newBucket(i + 1, true);
_indirect[i] = newBucket(i + 1, false);
}
}

@Override
public ByteBuffer acquire(int size, boolean direct)
{
int capacity = size < _minCapacity ? size : (bucketFor(size) + 1) * getCapacityFactor();
ByteBufferPool.Bucket bucket = bucketFor(size, direct, null);
int capacity = size < _minCapacity ? size : capacityFor(bucketFor(size));
ByteBufferPool.Bucket bucket = bucketFor(size, direct);
if (bucket == null)
return newByteBuffer(capacity, direct);
ByteBuffer buffer = bucket.acquire();
if (buffer == null)
return newByteBuffer(capacity, direct);
decrementMemory(buffer);
return buffer;
}

Expand All @@ -122,26 +135,29 @@ public void release(ByteBuffer buffer)

int capacity = buffer.capacity();
// Validate that this buffer is from this pool.
if ((capacity % getCapacityFactor()) != 0)
if (capacity != capacityFor(bucketFor(capacity)))
{
if (LOG.isDebugEnabled())
LOG.debug("ByteBuffer {} does not belong to this pool, discarding it", BufferUtil.toDetailString(buffer));
return;
}

// Don't release into the pool if greater than the maximum ByteBuffer capacity.
if (capacity > _maxCapacity)
return;

boolean direct = buffer.isDirect();
ByteBufferPool.Bucket bucket = bucketFor(capacity, direct, this::newBucket);
ByteBufferPool.Bucket bucket = bucketFor(capacity, direct);
if (bucket != null)
{
bucket.release(buffer);
incrementMemory(buffer);
releaseExcessMemory(direct, this::clearOldestBucket);
releaseExcessMemory(direct, this::releaseMemory);
}
}

private Bucket newBucket(int key)
private Bucket newBucket(int key, boolean direct)
{
return new Bucket(key * getCapacityFactor(), getMaxQueueLength());
return new Bucket(capacityFor(key), getMaxQueueLength(), updateMemory(direct));
}

@Override
Expand All @@ -150,26 +166,20 @@ public void clear()
super.clear();
for (int i = 0; i < _direct.length; ++i)
{
Bucket bucket = _direct[i];
if (bucket != null)
bucket.clear();
_direct[i] = null;
bucket = _indirect[i];
if (bucket != null)
bucket.clear();
_indirect[i] = null;
_direct[i].clear();
_indirect[i].clear();
}
}

private void clearOldestBucket(boolean direct)
protected void releaseMemory(boolean direct)
{
long oldest = Long.MAX_VALUE;
int index = -1;
Bucket[] buckets = bucketsFor(direct);
for (int i = 0; i < buckets.length; ++i)
{
Bucket bucket = buckets[i];
if (bucket == null)
if (bucket.isEmpty())
continue;
long lastUpdate = bucket.getLastUpdate();
if (lastUpdate < oldest)
Expand All @@ -181,31 +191,29 @@ private void clearOldestBucket(boolean direct)
if (index >= 0)
{
Bucket bucket = buckets[index];
buckets[index] = null;
// The same bucket may be concurrently
// removed, so we need this null guard.
if (bucket != null)
bucket.clear(this::decrementMemory);
bucket.clear();
}
}

private int bucketFor(int capacity)
protected int bucketFor(int capacity)
{
return (int)Math.ceil((double)capacity / getCapacityFactor());
}

protected int capacityFor(int bucket)
{
return (capacity - 1) / getCapacityFactor();
return bucket * getCapacityFactor();
}

private ByteBufferPool.Bucket bucketFor(int capacity, boolean direct, IntFunction<Bucket> newBucket)
private ByteBufferPool.Bucket bucketFor(int capacity, boolean direct)
{
if (capacity < _minCapacity)
return null;
int b = bucketFor(capacity);
if (b >= _direct.length)
int index = bucketFor(capacity) - 1;
if (index >= _direct.length)
return null;
Bucket[] buckets = bucketsFor(direct);
Bucket bucket = buckets[b];
if (bucket == null && newBucket != null)
buckets[b] = bucket = newBucket.apply(b + 1);
return bucket;
return buckets[index];
}

@ManagedAttribute("The number of pooled direct ByteBuffers")
Expand Down Expand Up @@ -233,4 +241,47 @@ ByteBufferPool.Bucket[] bucketsFor(boolean direct)
{
return direct ? _direct : _indirect;
}

public boolean isDetailedDump()
{
return _detailedDump;
}

public void setDetailedDump(boolean detailedDump)
{
_detailedDump = detailedDump;
}

@Override
public void dump(Appendable out, String indent) throws IOException
{
List<Object> dump = new ArrayList<>();
dump.add(String.format("HeapMemory: %d/%d", getHeapMemory(), getMaxHeapMemory()));
dump.add(String.format("DirectMemory: %d/%d", getDirectMemory(), getMaxDirectMemory()));

List<Bucket> indirect = Arrays.stream(_indirect).filter(b -> !b.isEmpty()).collect(Collectors.toList());
List<Bucket> direct = Arrays.stream(_direct).filter(b -> !b.isEmpty()).collect(Collectors.toList());
if (isDetailedDump())
{
dump.add(new DumpableCollection("Indirect Buckets", indirect));
dump.add(new DumpableCollection("Direct Buckets", direct));
}
else
{
dump.add("Indirect Buckets size=" + indirect.size());
dump.add("Direct Buckets size=" + direct.size());
}
Dumpable.dumpObjects(out, indent, this, dump);
}

@Override
public String toString()
{
return String.format("%s@%x{minBufferCapacity=%s, maxBufferCapacity=%s, maxQueueLength=%s, factor=%s}",
this.getClass().getSimpleName(), hashCode(),
_minCapacity,
_maxCapacity,
getMaxQueueLength(),
getCapacityFactor());
}
}

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