stan/jdk-24
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

8009063: Improve reliability of ConcurrentHashMap

Browse Source 
Reviewed-by: alanb, ahgross
This commit is contained in:
Chris Hegarty 2013-03-03 10:07:52 +00:00
parent b15549ed0b
commit 046d36e089
1 changed files with 27 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

28
jdk/src/share/classes/java/util/concurrent/ConcurrentHashMap.java
View File

@ -34,6 +34,7 @@
*/
package java.util.concurrent;
import java.io.ObjectInputStream;
import java.util.concurrent.locks.*;
import java.util.*;
import java.io.Serializable;
@ -1483,7 +1484,23 @@ public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
@SuppressWarnings("unchecked")
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
s.defaultReadObject();
// Don't call defaultReadObject()
ObjectInputStream.GetField oisFields = s.readFields();
final Segment<K,V>[] oisSegments = (Segment<K,V>[])oisFields.get("segments", null);
final int ssize = oisSegments.length;
if (ssize < 1 || ssize > MAX_SEGMENTS
|| (ssize & (ssize-1)) != 0 ) // ssize not power of two
throw new java.io.InvalidObjectException("Bad number of segments:"
+ ssize);
int sshift = 0, ssizeTmp = ssize;
while (ssizeTmp > 1) {
++sshift;
ssizeTmp >>>= 1;
}
UNSAFE.putIntVolatile(this, SEGSHIFT_OFFSET, 32 - sshift);
UNSAFE.putIntVolatile(this, SEGMASK_OFFSET, ssize - 1);
UNSAFE.putObjectVolatile(this, SEGMENTS_OFFSET, oisSegments);
// set hashMask
UNSAFE.putIntVolatile(this, HASHSEED_OFFSET,
@ -1517,6 +1534,9 @@ public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
private static final long TBASE;
private static final int TSHIFT;
private static final long HASHSEED_OFFSET;
private static final long SEGSHIFT_OFFSET;
private static final long SEGMASK_OFFSET;
private static final long SEGMENTS_OFFSET;
static {
int ss, ts;
@ -1530,6 +1550,12 @@ public class ConcurrentHashMap<K, V> extends AbstractMap<K, V>
ss = UNSAFE.arrayIndexScale(sc);
HASHSEED_OFFSET = UNSAFE.objectFieldOffset(
ConcurrentHashMap.class.getDeclaredField("hashSeed"));
SEGSHIFT_OFFSET = UNSAFE.objectFieldOffset(
ConcurrentHashMap.class.getDeclaredField("segmentShift"));
SEGMASK_OFFSET = UNSAFE.objectFieldOffset(
ConcurrentHashMap.class.getDeclaredField("segmentMask"));
SEGMENTS_OFFSET = UNSAFE.objectFieldOffset(
ConcurrentHashMap.class.getDeclaredField("segments"));
} catch (Exception e) {
throw new Error(e);
}