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/*
* Copyright (c) 2000, 2020, Oracle and/or its affiliates.
*
* Licensed under the Universal Permissive License v 1.0 as shown at
* http://oss.oracle.com/licenses/upl.
*/
package com.oracle.coherence.common.io;
import com.oracle.coherence.common.internal.io.AbstractBufferManager;
import com.oracle.coherence.common.internal.io.SegmentedBufferManager;
import com.oracle.coherence.common.internal.io.CheckedBufferManager;
import com.oracle.coherence.common.internal.io.SlabBufferManager;
import com.oracle.coherence.common.internal.io.WrapperBufferManager;
import com.oracle.coherence.common.util.MemorySize;
import java.nio.ByteBuffer;
import java.util.logging.Level;
import java.util.logging.Logger;
/**
* BufferManagers provides access to pre-defined system-wide managers.
*
* The default size of each of the pools may be specified via the com.oracle.common.io.BufferManagers.pool
* system property. Additionally com.oracle.common.io.BufferManagers.checked can be used to default all
* managers to utilize checked implementations to watch for pool usage issues.
*
*
* @author mf 2010.12.02
*/
public final class BufferManagers
{
/**
* Return the heap ByteBuffer based BufferManager.
*
* The maximum size of this buffer manager pool may be specified via the
* com.oracle.common.io.BufferManagers.heap.pool system property. Setting this
* value to 0 results in a non-pooled implementation. The default
* value is a small percentage of the JVM's total heap size.
*
* For pooled implementations setting com.oracle.common.io.BufferManagers.heap.checked
* to true will provide pool which provides more stringent checks
* in an attempt to ensure that the application doesn't misuse the pool,
* for instance by double releasing a buffer. The default value is false.
*
* @return the heap BufferManager
*/
public static BufferManager getHeapManager()
{
return HeapManagerHolder.INSTANCE;
}
/**
* Return the direct ByteBuffer based BufferManager.
*
* The maximum size of this buffer manager pool may be specified via the
* com.oracle.common.io.BufferManagers.direct.pool system property. Setting this
* value to 0 results in a non-pooled implementation. The default
* value is a small percentage of the JVM's total heap size.
*
* For pooled implementations setting com.oracle.common.io.BufferManagers.direct.checked
* to true will provide pool which provides more stringent checks
* in an attempt to ensure that the application doesn't misuse the pool,
* for instance by double releasing a buffer. The default value is false.
*
* @return the direct BufferManager
*/
public static BufferManager getDirectManager()
{
return DirectManagerHolder.INSTANCE;
}
/**
* Return the network optimized direct ByteBuffer based BufferManager.
*
* Compared with the {@link #getDirectManager DirectManager} this implementation
* may provide buffers which are more optimal for use in network operations.
* On some platforms this method may simply return the DirectManager.
*
* The maximum size of this buffer manager pool may be specified via the
* com.oracle.common.io.BufferManagers.network.pool system property. Setting this
* value to 0 results in a non-pooled implementation. The default
* value is a small percentage of the JVM's total heap size.
*
* For pooled implementations setting com.oracle.common.io.BufferManagers.network.checked
* to true will provide pool which provides more stringent checks
* in an attempt to ensure that the application doesn't misuse the pool,
* for instance by double releasing a buffer. The default value is false.
*
* @return the network direct BufferManager
*/
public static BufferManager getNetworkDirectManager()
{
return NetworkDirectManagerHolder.INSTANCE;
}
/**
* Holder for the heap based BufferManager.
*/
private static class HeapManagerHolder
{
/**
* The heap based BufferManager.
*/
public static final BufferManager INSTANCE;
static
{
BufferManager mgr;
String sHeap = System.getProperty(BufferManagers.class.getName()
+ ".heap.pool", System.getProperty(BufferManagers.class.getName()
+ ".pool", Long.toString(DEFAULT_POOL_SIZE)));
int cbBuf = (int) new MemorySize(System.getProperty(BufferManagers.class.getName() + ".heap.base",
System.getProperty(BufferManagers.class.getName() + ".base",
Long.toString(SegmentedBufferManager.DEFAULT_BUF_SIZE)))).getByteCount();
if (sHeap.startsWith("-")) // negative implies infinite which maps
// to the WeakBufferManager
{
//TODO initialize the WeakSegmentedBufferManager here
throw new IllegalStateException("Negative heap pool size");
}
else // sHeap is positive
{
long lcbPool = new MemorySize(sHeap).getByteCount();
if (lcbPool > 0L)
{
SegmentedBufferManager mgrSeg = new SegmentedBufferManager(new SegmentedBufferManager.BufferAllocator()
{
public ByteBuffer allocate(int cb)
{
return ByteBuffer.allocate(cb);
}
public void release(ByteBuffer buff)
{
if (buff.isDirect())
{
throw new IllegalArgumentException();
}
// nothing to do
}
public String toString()
{
return "HeapBufferAllocator";
}
}, cbBuf, lcbPool);
mgrSeg.setName("HeapBufferManager");
mgr = mgrSeg;
}
else // lcbPool == 0
{
mgr = new AbstractBufferManager()
{
public ByteBuffer acquire(int cb)
{
return ByteBuffer.allocate(cb);
}
public void dispose()
{
// no-op; top level manager
}
protected void ensureCompatibility(ByteBuffer buff)
{
if (buff.isDirect())
{
throw new IllegalArgumentException();
}
}
};
}
}
mgr = new NonDisposableBufferManager(mgr);
LOGGER.log(Level.FINE, "initialized HeapBufferManager " + mgr);
INSTANCE = Boolean.valueOf(System.getProperty(BufferManagers.class.getName() + ".heap.checked",
System.getProperty(BufferManagers.class.getName() + ".checked")))
? new CheckedBufferManager(mgr) : mgr;
}
}
/**
* Holder for the direct BufferManager.
*/
private static class DirectManagerHolder
{
/**
* The direct BufferManager.
*/
public static final BufferManager INSTANCE;
static
{
BufferManager mgr;
long lcbPool = new MemorySize(System.getProperty(BufferManagers.class.getName() + ".direct.pool",
System.getProperty(BufferManagers.class.getName() + ".pool",
Long.toString(DEFAULT_POOL_SIZE)))).getByteCount(); // default is doced above
int cbBuf = (int) new MemorySize(System.getProperty(BufferManagers.class.getName() + ".direct.base",
System.getProperty(BufferManagers.class.getName() + ".base",
Long.toString(SegmentedBufferManager.DEFAULT_BUF_SIZE)))).getByteCount();
if (lcbPool > 0L)
{
// for DirectByteBuffers we use a slab based buffer manager as DBB allocations are page aligned and thus
// consume significantly more memory then is requested.
SlabBufferManager mgrSlab = new SlabBufferManager(
new SlabBufferManager.DirectBufferAllocator(), cbBuf, lcbPool);
mgrSlab.setName("DirectBufferManager");
mgr = mgrSlab;
}
else // lcbPool == 0
{
mgr = new AbstractBufferManager()
{
public ByteBuffer acquire(int cb)
{
return ByteBuffer.allocateDirect(cb);
}
public void dispose()
{
// no-op; top level manager
}
protected void ensureCompatibility(ByteBuffer buff)
{
if (!buff.isDirect())
{
throw new IllegalArgumentException();
}
}
};
}
mgr = new NonDisposableBufferManager(mgr);
LOGGER.log(Level.FINE, "initialized DirectBufferManager " + mgr);
INSTANCE = Boolean.valueOf(System.getProperty(BufferManagers.class.getName() + ".direct.checked",
System.getProperty(BufferManagers.class.getName() + ".checked")))
? new CheckedBufferManager(mgr) : mgr;
}
}
/**
* Holder for the network direct BufferManager.
*/
private static class NetworkDirectManagerHolder
{
/**
* The network direct BufferManager.
*/
public static final BufferManager INSTANCE = DirectManagerHolder.INSTANCE;
}
/**
* A {@link WrapperBufferManager} which cannot be disposed.
*/
private static class NonDisposableBufferManager
extends WrapperBufferManager
{
/**
* Create a new NonDisposableBufferManager wrapping the passed
* BufferManager.
*
* @param delegate the BufferManager to wrap
*/
public NonDisposableBufferManager(BufferManager delegate)
{
super(delegate);
}
@Override
public void dispose()
{
throw new UnsupportedOperationException();
}
}
/**
* The default amount of memory for each pool.
*
* The goal is to select a size which won't consume too much of the total java heap. We target a limit
* which is 5% of the max heap size -Xmx, but also defend against configurations which may not have specified
* -Xmx in which case we limit ourselves to decent portion of the initial heap size, since the heap has no
* apparent upper bound this is also a small portion.
*/
private static final long DEFAULT_POOL_SIZE = Math.min(/*~Xms*/ Runtime.getRuntime().totalMemory() / 4,
/* Xmx*/Runtime.getRuntime().maxMemory() / 20);
/**
* The Logger for the managers.
*/
private static final Logger LOGGER = Logger.getLogger(BufferManagers.class.getName());
/**
* Indicates if buffers should have their contents zeroed out upon release.
*
* There is a performance impact to enabling this, it effectively negates the benefits of zcopy
*/
public static final boolean ZERO_ON_RELEASE = Boolean.getBoolean(
BufferManagers.class.getName() + ".zeroed");
}