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8199462: Use Reference.reachabilityFence in direct ByteBuffer methods

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Reviewed-by: psandoz, vlivanov, plevart
This commit is contained in:
Ben Walsh 2018-03-12 16:09:18 -07:00 committed by Paul Sandoz
parent f439f2166b
commit de3604ea0c
6 changed files with 113 additions and 67 deletions
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12
src/java.base/share/classes/java/lang/ref/Reference.java
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@ -25,7 +25,7 @@
package java.lang.ref;
import jdk.internal.vm.annotation.DontInline;
import jdk.internal.vm.annotation.ForceInline;
import jdk.internal.HotSpotIntrinsicCandidate;
import jdk.internal.misc.JavaLangRefAccess;
import jdk.internal.misc.SharedSecrets;
@ -420,10 +420,12 @@ public abstract class Reference<T> {
* @param ref the reference. If {@code null}, this method has no effect.
* @since 9
*/
@DontInline
@ForceInline
public static void reachabilityFence(Object ref) {
// Does nothing, because this method is annotated with @DontInline
// HotSpot needs to retain the ref and not GC it before a call to this
// method
// Does nothing. This method is annotated with @ForceInline to eliminate
// most of the overhead that using @DontInline would cause with the
// HotSpot JVM, when this fence is used in a wide variety of situations.
// HotSpot JVM retains the ref and does not GC it before a call to
// this method, because the JIT-compilers do not have GC-only safepoints.
}
}

30
src/java.base/share/classes/java/nio/Direct-X-Buffer-bin.java.template
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@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -32,24 +32,40 @@ class XXX {
#if[rw]
private $type$ get$Type$(long a) {
$memtype$ x = UNSAFE.get$Memtype$Unaligned(null, a, bigEndian);
return $fromBits$(x);
try {
$memtype$ x = UNSAFE.get$Memtype$Unaligned(null, a, bigEndian);
return $fromBits$(x);
} finally {
Reference.reachabilityFence(this);
}
}
public $type$ get$Type$() {
return get$Type$(ix(nextGetIndex($BYTES_PER_VALUE$)));
try {
return get$Type$(ix(nextGetIndex($BYTES_PER_VALUE$)));
} finally {
Reference.reachabilityFence(this);
}
}
public $type$ get$Type$(int i) {
return get$Type$(ix(checkIndex(i, $BYTES_PER_VALUE$)));
try {
return get$Type$(ix(checkIndex(i, $BYTES_PER_VALUE$)));
} finally {
Reference.reachabilityFence(this);
}
}
#end[rw]
private ByteBuffer put$Type$(long a, $type$ x) {
#if[rw]
$memtype$ y = $toBits$(x);
UNSAFE.put$Memtype$Unaligned(null, a, y, bigEndian);
try {
$memtype$ y = $toBits$(x);
UNSAFE.put$Memtype$Unaligned(null, a, y, bigEndian);
} finally {
Reference.reachabilityFence(this);
}
return this;
#else[rw]
throw new ReadOnlyBufferException();

112
src/java.base/share/classes/java/nio/Direct-X-Buffer.java.template
View File

@ -1,5 +1,5 @@
/*
* Copyright (c) 2000, 2016, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2000, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@ -28,6 +28,7 @@
package java.nio;
import java.io.FileDescriptor;
import java.lang.ref.Reference;
import jdk.internal.misc.VM;
import jdk.internal.ref.Cleaner;
import sun.nio.ch.DirectBuffer;
@ -257,16 +258,28 @@ class Direct$Type$Buffer$RW$$BO$
}
public $type$ get() {
return $fromBits$($swap$(UNSAFE.get$Swaptype$(ix(nextGetIndex()))));
try {
return $fromBits$($swap$(UNSAFE.get$Swaptype$(ix(nextGetIndex()))));
} finally {
Reference.reachabilityFence(this);
}
}
public $type$ get(int i) {
return $fromBits$($swap$(UNSAFE.get$Swaptype$(ix(checkIndex(i)))));
try {
return $fromBits$($swap$(UNSAFE.get$Swaptype$(ix(checkIndex(i)))));
} finally {
Reference.reachabilityFence(this);
}
}
#if[streamableType]
$type$ getUnchecked(int i) {
return $fromBits$($swap$(UNSAFE.get$Swaptype$(ix(i))));
try {
return $fromBits$($swap$(UNSAFE.get$Swaptype$(ix(i))));
} finally {
Reference.reachabilityFence(this);
}
}
#end[streamableType]
@ -282,21 +295,25 @@ class Direct$Type$Buffer$RW$$BO$
throw new BufferUnderflowException();
long dstOffset = ARRAY_BASE_OFFSET + ((long)offset << $LG_BYTES_PER_VALUE$);
try {
#if[!byte]
if (order() != ByteOrder.nativeOrder())
UNSAFE.copySwapMemory(null,
if (order() != ByteOrder.nativeOrder())
UNSAFE.copySwapMemory(null,
ix(pos),
dst,
dstOffset,
(long)length << $LG_BYTES_PER_VALUE$,
(long)1 << $LG_BYTES_PER_VALUE$);
else
#end[!byte]
UNSAFE.copyMemory(null,
ix(pos),
dst,
dstOffset,
(long)length << $LG_BYTES_PER_VALUE$,
(long)1 << $LG_BYTES_PER_VALUE$);
else
#end[!byte]
UNSAFE.copyMemory(null,
ix(pos),
dst,
dstOffset,
(long)length << $LG_BYTES_PER_VALUE$);
(long)length << $LG_BYTES_PER_VALUE$);
} finally {
Reference.reachabilityFence(this);
}
position(pos + length);
} else {
super.get(dst, offset, length);
@ -311,7 +328,11 @@ class Direct$Type$Buffer$RW$$BO$
public $Type$Buffer put($type$ x) {
#if[rw]
UNSAFE.put$Swaptype$(ix(nextPutIndex()), $swap$($toBits$(x)));
try {
UNSAFE.put$Swaptype$(ix(nextPutIndex()), $swap$($toBits$(x)));
} finally {
Reference.reachabilityFence(this);
}
return this;
#else[rw]
throw new ReadOnlyBufferException();
@ -320,7 +341,11 @@ class Direct$Type$Buffer$RW$$BO$
public $Type$Buffer put(int i, $type$ x) {
#if[rw]
UNSAFE.put$Swaptype$(ix(checkIndex(i)), $swap$($toBits$(x)));
try {
UNSAFE.put$Swaptype$(ix(checkIndex(i)), $swap$($toBits$(x)));
} finally {
Reference.reachabilityFence(this);
}
return this;
#else[rw]
throw new ReadOnlyBufferException();
@ -346,7 +371,12 @@ class Direct$Type$Buffer$RW$$BO$
if (srem > rem)
throw new BufferOverflowException();
UNSAFE.copyMemory(sb.ix(spos), ix(pos), (long)srem << $LG_BYTES_PER_VALUE$);
try {
UNSAFE.copyMemory(sb.ix(spos), ix(pos), (long)srem << $LG_BYTES_PER_VALUE$);
} finally {
Reference.reachabilityFence(sb);
Reference.reachabilityFence(this);
}
sb.position(spos + srem);
position(pos + srem);
} else if (src.hb != null) {
@ -380,21 +410,25 @@ class Direct$Type$Buffer$RW$$BO$
throw new BufferOverflowException();
long srcOffset = ARRAY_BASE_OFFSET + ((long)offset << $LG_BYTES_PER_VALUE$);
try {
#if[!byte]
if (order() != ByteOrder.nativeOrder())
UNSAFE.copySwapMemory(src,
if (order() != ByteOrder.nativeOrder())
UNSAFE.copySwapMemory(src,
srcOffset,
null,
ix(pos),
(long)length << $LG_BYTES_PER_VALUE$,
(long)1 << $LG_BYTES_PER_VALUE$);
else
#end[!byte]
UNSAFE.copyMemory(src,
srcOffset,
null,
ix(pos),
(long)length << $LG_BYTES_PER_VALUE$,
(long)1 << $LG_BYTES_PER_VALUE$);
else
#end[!byte]
UNSAFE.copyMemory(src,
srcOffset,
null,
ix(pos),
(long)length << $LG_BYTES_PER_VALUE$);
(long)length << $LG_BYTES_PER_VALUE$);
} finally {
Reference.reachabilityFence(this);
}
position(pos + length);
} else {
super.put(src, offset, length);
@ -411,8 +445,11 @@ class Direct$Type$Buffer$RW$$BO$
int lim = limit();
assert (pos <= lim);
int rem = (pos <= lim ? lim - pos : 0);
UNSAFE.copyMemory(ix(pos), ix(0), (long)rem << $LG_BYTES_PER_VALUE$);
try {
UNSAFE.copyMemory(ix(pos), ix(0), (long)rem << $LG_BYTES_PER_VALUE$);
} finally {
Reference.reachabilityFence(this);
}
position(rem);
limit(capacity());
discardMark();
@ -497,19 +534,6 @@ class Direct$Type$Buffer$RW$$BO$
#if[byte]
byte _get(int i) { // package-private
return UNSAFE.getByte(address + i);
}
void _put(int i, byte b) { // package-private
#if[rw]
UNSAFE.putByte(address + i, b);
#else[rw]
throw new ReadOnlyBufferException();
#end[rw]
}
// #BIN
//
// Binary-data access methods for short, char, int, long, float,

13
src/java.base/share/classes/java/nio/MappedByteBuffer.java
View File

@ -26,6 +26,7 @@
package java.nio;
import java.io.FileDescriptor;
import java.lang.ref.Reference;
import jdk.internal.misc.Unsafe;
@ -166,9 +167,15 @@ public abstract class MappedByteBuffer
int count = Bits.pageCount(length);
long a = mappingAddress(offset);
byte x = 0;
for (int i=0; i<count; i++) {
x ^= unsafe.getByte(a);
a += ps;
try {
for (int i=0; i<count; i++) {
// TODO consider changing to getByteOpaque thus avoiding
// dead code elimination and the need to calculate a checksum
x ^= unsafe.getByte(a);
a += ps;
}
} finally {
Reference.reachabilityFence(this);
}
if (unused != 0)
unused = x;

5
src/java.base/share/classes/java/nio/X-Buffer.java.template
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@ -1749,11 +1749,6 @@ public abstract class $Type$Buffer
abstract ByteBuffer slice(int pos, int lim);
// Unchecked accessors, for use by ByteBufferAs-X-Buffer classes
//
abstract byte _get(int i); // package-private
abstract void _put(int i, byte b); // package-private
// #BIN
//
// Binary-data access methods for short, char, int, long, float,

8
test/jdk/java/lang/ref/ReachabilityFenceTest.java
View File

@ -122,9 +122,11 @@ public class ReachabilityFenceTest {
}
}
Reference.reachabilityFence(o);
return finalized.get();
try {
return finalized.get();
} finally {
Reference.reachabilityFence(o);
}
}
private static class MyFinalizeable {