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NioEventLoop should also use our special SelectionKeySet on Java9 and later. (#8260)

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Motivation:

In Java8 and earlier we used reflection to replace the used key set if not otherwise told. This does not work on Java9 and later without special flags as its not possible to call setAccessible(true) on the Field anymore.

Modifications:

- Use Unsafe to instrument the Selector with out special set when sun.misc.Unsafe is present and we are using Java9+.

Result:

NIO transport produce less GC on Java9 and later as well.
This commit is contained in:
Norman Maurer 2018-09-05 07:23:03 +02:00 committed by GitHub
parent ade60c11e1
commit 3c2dbdb5db
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3 changed files with 32 additions and 3 deletions
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9
common/src/main/java/io/netty/util/internal/PlatformDependent.java
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@ -29,6 +29,7 @@ import org.jctools.util.Pow2;
import org.jctools.util.UnsafeAccess;
import java.io.File;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
@ -567,6 +568,14 @@ public final class PlatformDependent {
PlatformDependent0.putLong(data, index, value);
}
public static void putObject(Object o, long offset, Object x) {
PlatformDependent0.putObject(o, offset, x);
}
public static long objectFieldOffset(Field field) {
return PlatformDependent0.objectFieldOffset(field);
}
public static void copyMemory(long srcAddr, long dstAddr, long length) {
PlatformDependent0.copyMemory(srcAddr, dstAddr, length);
}

4
common/src/main/java/io/netty/util/internal/PlatformDependent0.java
View File

@ -568,6 +568,10 @@ final class PlatformDependent0 {
UNSAFE.putLong(data, BYTE_ARRAY_BASE_OFFSET + index, value);
}
static void putObject(Object o, long offset, Object x) {
UNSAFE.putObject(o, offset, x);
}
static void copyMemory(long srcAddr, long dstAddr, long length) {
// Manual safe-point polling is only needed prior Java9:
// See https://bugs.openjdk.java.net/browse/JDK-8149596

18
transport/src/main/java/io/netty/channel/nio/NioEventLoop.java
View File

@ -43,7 +43,6 @@ import java.util.Collection;
import java.util.Iterator;
import java.util.Queue;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.Executor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
@ -207,6 +206,23 @@ public final class NioEventLoop extends SingleThreadEventLoop {
Field selectedKeysField = selectorImplClass.getDeclaredField("selectedKeys");
Field publicSelectedKeysField = selectorImplClass.getDeclaredField("publicSelectedKeys");
if (PlatformDependent.javaVersion() >= 9 && PlatformDependent.hasUnsafe()) {
// Let us try to use sun.misc.Unsafe to replace the SelectionKeySet.
// This allows us to also do this in Java9+ without any extra flags.
long selectedKeysFieldOffset = PlatformDependent.objectFieldOffset(selectedKeysField);
long publicSelectedKeysFieldOffset =
PlatformDependent.objectFieldOffset(publicSelectedKeysField);
if (selectedKeysFieldOffset != -1 && publicSelectedKeysFieldOffset != -1) {
PlatformDependent.putObject(
unwrappedSelector, selectedKeysFieldOffset, selectedKeySet);
PlatformDependent.putObject(
unwrappedSelector, publicSelectedKeysFieldOffset, selectedKeySet);
return null;
}
// We could not retrieve the offset, lets try reflection as last-resort.
}
Throwable cause = ReflectionUtil.trySetAccessible(selectedKeysField, true);
if (cause != null) {
return cause;