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Posted to hdfs-commits@hadoop.apache.org by sz...@apache.org on 2012/08/17 03:54:17 UTC
svn commit: r1374127 - in
/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs: CHANGES.txt
src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java
Author: szetszwo
Date: Fri Aug 17 01:54:16 2012
New Revision: 1374127
URL: http://svn.apache.org/viewvc?rev=1374127&view=rev
Log:
HDFS-2421. Improve the concurrency of SerialNumberMap in NameNode. Contributed by Jing Zhao and Weiyan Wang
Modified:
hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java
Modified: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt?rev=1374127&r1=1374126&r2=1374127&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt (original)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt Fri Aug 17 01:54:16 2012
@@ -415,6 +415,9 @@ Branch-2 ( Unreleased changes )
HDFS-3697. Enable fadvise readahead by default. (todd)
+ HDFS-2421. Improve the concurrency of SerialNumberMap in NameNode.
+ (Jing Zhao and Weiyan Wang via szetszwo)
+
BUG FIXES
HDFS-3385. The last block of INodeFileUnderConstruction is not
Modified: hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java
URL: http://svn.apache.org/viewvc/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java?rev=1374127&r1=1374126&r2=1374127&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java (original)
+++ hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/SerialNumberManager.java Fri Aug 17 01:54:16 2012
@@ -17,7 +17,10 @@
*/
package org.apache.hadoop.hdfs.server.namenode;
-import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ConcurrentMap;
+import java.util.concurrent.atomic.AtomicInteger;
+
/** Manage name-to-serial-number maps for users and groups. */
class SerialNumberManager {
@@ -40,33 +43,41 @@ class SerialNumberManager {
}
private static class SerialNumberMap<T> {
- private int max = 0;
- private int nextSerialNumber() {return max++;}
-
- private Map<T, Integer> t2i = new HashMap<T, Integer>();
- private Map<Integer, T> i2t = new HashMap<Integer, T>();
-
- synchronized int get(T t) {
+ private AtomicInteger max = new AtomicInteger(1);
+ private ConcurrentMap<T, Integer> t2i = new ConcurrentHashMap<T, Integer>();
+ private ConcurrentMap<Integer, T> i2t = new ConcurrentHashMap<Integer, T>();
+
+ int get(T t) {
+ if (t == null) {
+ return 0;
+ }
Integer sn = t2i.get(t);
if (sn == null) {
- sn = nextSerialNumber();
- t2i.put(t, sn);
+ sn = max.getAndIncrement();
+ Integer old = t2i.putIfAbsent(t, sn);
+ if (old != null) {
+ return old;
+ }
i2t.put(sn, t);
}
return sn;
}
- synchronized T get(int i) {
- if (!i2t.containsKey(i)) {
+ T get(int i) {
+ if (i == 0) {
+ return null;
+ }
+ T t = i2t.get(i);
+ if (t == null) {
throw new IllegalStateException("!i2t.containsKey(" + i
+ "), this=" + this);
}
- return i2t.get(i);
+ return t;
}
- @Override
+ /** {@inheritDoc} */
public String toString() {
return "max=" + max + ",\n t2i=" + t2i + ",\n i2t=" + i2t;
}
}
-}
+}
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