io.netty.buffer.PoolThreadCache Maven / Gradle / Ivy
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This artifact provides a single jar that contains all classes required to use remote EJB and JMS, including
all dependencies. It is intended for use by those not using maven, maven users should just import the EJB and
JMS BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up
with different versions on classes on the class path).
/*
* Copyright 2012 The Netty Project
*
* The Netty Project 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:
*
* https://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 io.netty.buffer;
import static io.netty.util.internal.ObjectUtil.checkPositiveOrZero;
import io.netty.buffer.PoolArena.SizeClass;
import io.netty.util.Recycler.EnhancedHandle;
import io.netty.util.internal.MathUtil;
import io.netty.util.internal.ObjectPool;
import io.netty.util.internal.ObjectPool.Handle;
import io.netty.util.internal.ObjectPool.ObjectCreator;
import io.netty.util.internal.PlatformDependent;
import io.netty.util.internal.logging.InternalLogger;
import io.netty.util.internal.logging.InternalLoggerFactory;
import java.nio.ByteBuffer;
import java.util.ArrayList;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.atomic.AtomicBoolean;
/**
* Acts a Thread cache for allocations. This implementation is moduled after
* jemalloc and the descripted
* technics of
*
* Scalable memory allocation using jemalloc.
*/
final class PoolThreadCache {
private static final InternalLogger logger = InternalLoggerFactory.getInstance(PoolThreadCache.class);
private static final int INTEGER_SIZE_MINUS_ONE = Integer.SIZE - 1;
final PoolArena heapArena;
final PoolArena directArena;
// Hold the caches for the different size classes, which are small and normal.
private final MemoryRegionCache[] smallSubPageHeapCaches;
private final MemoryRegionCache[] smallSubPageDirectCaches;
private final MemoryRegionCache[] normalHeapCaches;
private final MemoryRegionCache[] normalDirectCaches;
private final int freeSweepAllocationThreshold;
private final AtomicBoolean freed = new AtomicBoolean();
@SuppressWarnings("unused") // Field is only here for the finalizer.
private final FreeOnFinalize freeOnFinalize;
private int allocations;
// TODO: Test if adding padding helps under contention
//private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
PoolThreadCache(PoolArena heapArena, PoolArena directArena,
int smallCacheSize, int normalCacheSize, int maxCachedBufferCapacity,
int freeSweepAllocationThreshold, boolean useFinalizer) {
checkPositiveOrZero(maxCachedBufferCapacity, "maxCachedBufferCapacity");
this.freeSweepAllocationThreshold = freeSweepAllocationThreshold;
this.heapArena = heapArena;
this.directArena = directArena;
if (directArena != null) {
smallSubPageDirectCaches = createSubPageCaches(smallCacheSize, directArena.sizeClass.nSubpages);
normalDirectCaches = createNormalCaches(normalCacheSize, maxCachedBufferCapacity, directArena);
directArena.numThreadCaches.getAndIncrement();
} else {
// No directArea is configured so just null out all caches
smallSubPageDirectCaches = null;
normalDirectCaches = null;
}
if (heapArena != null) {
// Create the caches for the heap allocations
smallSubPageHeapCaches = createSubPageCaches(smallCacheSize, heapArena.sizeClass.nSubpages);
normalHeapCaches = createNormalCaches(normalCacheSize, maxCachedBufferCapacity, heapArena);
heapArena.numThreadCaches.getAndIncrement();
} else {
// No heapArea is configured so just null out all caches
smallSubPageHeapCaches = null;
normalHeapCaches = null;
}
// Only check if there are caches in use.
if ((smallSubPageDirectCaches != null || normalDirectCaches != null
|| smallSubPageHeapCaches != null || normalHeapCaches != null)
&& freeSweepAllocationThreshold < 1) {
throw new IllegalArgumentException("freeSweepAllocationThreshold: "
+ freeSweepAllocationThreshold + " (expected: > 0)");
}
freeOnFinalize = useFinalizer ? new FreeOnFinalize(this) : null;
}
private static MemoryRegionCache[] createSubPageCaches(
int cacheSize, int numCaches) {
if (cacheSize > 0 && numCaches > 0) {
@SuppressWarnings("unchecked")
MemoryRegionCache[] cache = new MemoryRegionCache[numCaches];
for (int i = 0; i < cache.length; i++) {
// TODO: maybe use cacheSize / cache.length
cache[i] = new SubPageMemoryRegionCache(cacheSize);
}
return cache;
} else {
return null;
}
}
@SuppressWarnings("unchecked")
private static MemoryRegionCache[] createNormalCaches(
int cacheSize, int maxCachedBufferCapacity, PoolArena area) {
if (cacheSize > 0 && maxCachedBufferCapacity > 0) {
int max = Math.min(area.sizeClass.chunkSize, maxCachedBufferCapacity);
// Create as many normal caches as we support based on how many sizeIdx we have and what the upper
// bound is that we want to cache in general.
List> cache = new ArrayList>() ;
for (int idx = area.sizeClass.nSubpages; idx < area.sizeClass.nSizes &&
area.sizeClass.sizeIdx2size(idx) <= max; idx++) {
cache.add(new NormalMemoryRegionCache(cacheSize));
}
return cache.toArray(new MemoryRegionCache[0]);
} else {
return null;
}
}
// val > 0
static int log2(int val) {
return INTEGER_SIZE_MINUS_ONE - Integer.numberOfLeadingZeros(val);
}
/**
* Try to allocate a small buffer out of the cache. Returns {@code true} if successful {@code false} otherwise
*/
boolean allocateSmall(PoolArena area, PooledByteBuf buf, int reqCapacity, int sizeIdx) {
return allocate(cacheForSmall(area, sizeIdx), buf, reqCapacity);
}
/**
* Try to allocate a normal buffer out of the cache. Returns {@code true} if successful {@code false} otherwise
*/
boolean allocateNormal(PoolArena area, PooledByteBuf buf, int reqCapacity, int sizeIdx) {
return allocate(cacheForNormal(area, sizeIdx), buf, reqCapacity);
}
@SuppressWarnings({ "unchecked", "rawtypes" })
private boolean allocate(MemoryRegionCache cache, PooledByteBuf buf, int reqCapacity) {
if (cache == null) {
// no cache found so just return false here
return false;
}
boolean allocated = cache.allocate(buf, reqCapacity, this);
if (++ allocations >= freeSweepAllocationThreshold) {
allocations = 0;
trim();
}
return allocated;
}
/**
* Add {@link PoolChunk} and {@code handle} to the cache if there is enough room.
* Returns {@code true} if it fit into the cache {@code false} otherwise.
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
boolean add(PoolArena area, PoolChunk chunk, ByteBuffer nioBuffer,
long handle, int normCapacity, SizeClass sizeClass) {
int sizeIdx = area.sizeClass.size2SizeIdx(normCapacity);
MemoryRegionCache cache = cache(area, sizeIdx, sizeClass);
if (cache == null) {
return false;
}
if (freed.get()) {
return false;
}
return cache.add(chunk, nioBuffer, handle, normCapacity);
}
private MemoryRegionCache cache(PoolArena area, int sizeIdx, SizeClass sizeClass) {
switch (sizeClass) {
case Normal:
return cacheForNormal(area, sizeIdx);
case Small:
return cacheForSmall(area, sizeIdx);
default:
throw new Error();
}
}
/**
* Should be called if the Thread that uses this cache is about to exist to release resources out of the cache
*/
void free(boolean finalizer) {
// As free() may be called either by the finalizer or by FastThreadLocal.onRemoval(...) we need to ensure
// we only call this one time.
if (freed.compareAndSet(false, true)) {
if (freeOnFinalize != null) {
// Help GC: this can race with a finalizer thread, but will be null out regardless
freeOnFinalize.cache = null;
}
int numFreed = free(smallSubPageDirectCaches, finalizer) +
free(normalDirectCaches, finalizer) +
free(smallSubPageHeapCaches, finalizer) +
free(normalHeapCaches, finalizer);
if (numFreed > 0 && logger.isDebugEnabled()) {
logger.debug("Freed {} thread-local buffer(s) from thread: {}", numFreed,
Thread.currentThread().getName());
}
if (directArena != null) {
directArena.numThreadCaches.getAndDecrement();
}
if (heapArena != null) {
heapArena.numThreadCaches.getAndDecrement();
}
}
}
private static int free(MemoryRegionCache[] caches, boolean finalizer) {
if (caches == null) {
return 0;
}
int numFreed = 0;
for (MemoryRegionCache c: caches) {
numFreed += free(c, finalizer);
}
return numFreed;
}
private static int free(MemoryRegionCache cache, boolean finalizer) {
if (cache == null) {
return 0;
}
return cache.free(finalizer);
}
void trim() {
trim(smallSubPageDirectCaches);
trim(normalDirectCaches);
trim(smallSubPageHeapCaches);
trim(normalHeapCaches);
}
private static void trim(MemoryRegionCache[] caches) {
if (caches == null) {
return;
}
for (MemoryRegionCache c: caches) {
trim(c);
}
}
private static void trim(MemoryRegionCache cache) {
if (cache == null) {
return;
}
cache.trim();
}
private MemoryRegionCache cacheForSmall(PoolArena area, int sizeIdx) {
if (area.isDirect()) {
return cache(smallSubPageDirectCaches, sizeIdx);
}
return cache(smallSubPageHeapCaches, sizeIdx);
}
private MemoryRegionCache cacheForNormal(PoolArena area, int sizeIdx) {
// We need to subtract area.sizeClass.nSubpages as sizeIdx is the overall index for all sizes.
int idx = sizeIdx - area.sizeClass.nSubpages;
if (area.isDirect()) {
return cache(normalDirectCaches, idx);
}
return cache(normalHeapCaches, idx);
}
private static MemoryRegionCache cache(MemoryRegionCache[] cache, int sizeIdx) {
if (cache == null || sizeIdx > cache.length - 1) {
return null;
}
return cache[sizeIdx];
}
/**
* Cache used for buffers which are backed by TINY or SMALL size.
*/
private static final class SubPageMemoryRegionCache extends MemoryRegionCache {
SubPageMemoryRegionCache(int size) {
super(size, SizeClass.Small);
}
@Override
protected void initBuf(
PoolChunk chunk, ByteBuffer nioBuffer, long handle, PooledByteBuf buf, int reqCapacity,
PoolThreadCache threadCache) {
chunk.initBufWithSubpage(buf, nioBuffer, handle, reqCapacity, threadCache);
}
}
/**
* Cache used for buffers which are backed by NORMAL size.
*/
private static final class NormalMemoryRegionCache extends MemoryRegionCache {
NormalMemoryRegionCache(int size) {
super(size, SizeClass.Normal);
}
@Override
protected void initBuf(
PoolChunk chunk, ByteBuffer nioBuffer, long handle, PooledByteBuf buf, int reqCapacity,
PoolThreadCache threadCache) {
chunk.initBuf(buf, nioBuffer, handle, reqCapacity, threadCache);
}
}
private abstract static class MemoryRegionCache {
private final int size;
private final Queue> queue;
private final SizeClass sizeClass;
private int allocations;
MemoryRegionCache(int size, SizeClass sizeClass) {
this.size = MathUtil.safeFindNextPositivePowerOfTwo(size);
queue = PlatformDependent.newFixedMpscQueue(this.size);
this.sizeClass = sizeClass;
}
/**
* Init the {@link PooledByteBuf} using the provided chunk and handle with the capacity restrictions.
*/
protected abstract void initBuf(PoolChunk chunk, ByteBuffer nioBuffer, long handle,
PooledByteBuf buf, int reqCapacity, PoolThreadCache threadCache);
/**
* Add to cache if not already full.
*/
@SuppressWarnings("unchecked")
public final boolean add(PoolChunk chunk, ByteBuffer nioBuffer, long handle, int normCapacity) {
Entry entry = newEntry(chunk, nioBuffer, handle, normCapacity);
boolean queued = queue.offer(entry);
if (!queued) {
// If it was not possible to cache the chunk, immediately recycle the entry
entry.unguardedRecycle();
}
return queued;
}
/**
* Allocate something out of the cache if possible and remove the entry from the cache.
*/
public final boolean allocate(PooledByteBuf buf, int reqCapacity, PoolThreadCache threadCache) {
Entry entry = queue.poll();
if (entry == null) {
return false;
}
initBuf(entry.chunk, entry.nioBuffer, entry.handle, buf, reqCapacity, threadCache);
entry.unguardedRecycle();
// allocations is not thread-safe which is fine as this is only called from the same thread all time.
++ allocations;
return true;
}
/**
* Clear out this cache and free up all previous cached {@link PoolChunk}s and {@code handle}s.
*/
public final int free(boolean finalizer) {
return free(Integer.MAX_VALUE, finalizer);
}
private int free(int max, boolean finalizer) {
int numFreed = 0;
for (; numFreed < max; numFreed++) {
Entry entry = queue.poll();
if (entry != null) {
freeEntry(entry, finalizer);
} else {
// all cleared
return numFreed;
}
}
return numFreed;
}
/**
* Free up cached {@link PoolChunk}s if not allocated frequently enough.
*/
public final void trim() {
int free = size - allocations;
allocations = 0;
// We not even allocated all the number that are
if (free > 0) {
free(free, false);
}
}
@SuppressWarnings({ "unchecked", "rawtypes" })
private void freeEntry(Entry entry, boolean finalizer) {
// Capture entry state before we recycle the entry object.
PoolChunk chunk = entry.chunk;
long handle = entry.handle;
ByteBuffer nioBuffer = entry.nioBuffer;
int normCapacity = entry.normCapacity;
if (!finalizer) {
// recycle now so PoolChunk can be GC'ed. This will only be done if this is not freed because of
// a finalizer.
entry.recycle();
}
chunk.arena.freeChunk(chunk, handle, normCapacity, sizeClass, nioBuffer, finalizer);
}
static final class Entry {
final EnhancedHandle> recyclerHandle;
PoolChunk chunk;
ByteBuffer nioBuffer;
long handle = -1;
int normCapacity;
Entry(Handle> recyclerHandle) {
this.recyclerHandle = (EnhancedHandle>) recyclerHandle;
}
void recycle() {
chunk = null;
nioBuffer = null;
handle = -1;
recyclerHandle.recycle(this);
}
void unguardedRecycle() {
chunk = null;
nioBuffer = null;
handle = -1;
recyclerHandle.unguardedRecycle(this);
}
}
@SuppressWarnings("rawtypes")
private static Entry newEntry(PoolChunk chunk, ByteBuffer nioBuffer, long handle, int normCapacity) {
Entry entry = RECYCLER.get();
entry.chunk = chunk;
entry.nioBuffer = nioBuffer;
entry.handle = handle;
entry.normCapacity = normCapacity;
return entry;
}
@SuppressWarnings("rawtypes")
private static final ObjectPool RECYCLER = ObjectPool.newPool(new ObjectCreator() {
@SuppressWarnings("unchecked")
@Override
public Entry newObject(Handle handle) {
return new Entry(handle);
}
});
}
private static final class FreeOnFinalize {
private volatile PoolThreadCache cache;
private FreeOnFinalize(PoolThreadCache cache) {
this.cache = cache;
}
/// TODO: In the future when we move to Java9+ we should use java.lang.ref.Cleaner.
@SuppressWarnings({"FinalizeDeclaration", "deprecation"})
@Override
protected void finalize() throws Throwable {
try {
super.finalize();
} finally {
PoolThreadCache cache = this.cache;
// this can race with a non-finalizer thread calling free: regardless who wins, the cache will be
// null out
this.cache = null;
if (cache != null) {
cache.free(true);
}
}
}
}
}