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svn merge -c 1541750 from trunk for HADOOP-10095. In CodecPool, synchronize pool and codecList separately in order to reduce lock contention. 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1541751 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Tsz-wo Sze 2013-11-13 22:51:43 +00:00
parent d993d01cdf
commit 79e34c2a3c
2 changed files with 19 additions and 15 deletions
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3
hadoop-common-project/hadoop-common/CHANGES.txt
View File

@ -88,6 +88,9 @@ Release 2.3.0 - UNRELEASED
HADOOP-9594. Update apache commons math dependency (Timothy St. Clair via
stevel)
HADOOP-10095. In CodecPool, synchronize pool and codecList separately in
order to reduce lock contention. (Nicolas Liochon via szetszwo)
OPTIMIZATIONS
HADOOP-9748. Reduce blocking on UGI.ensureInitialized (daryn)

31
hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/compress/CodecPool.java
View File

@ -85,16 +85,15 @@ public class CodecPool {
T codec = null;
// Check if an appropriate codec is available
List<T> codecList;
synchronized (pool) {
if (pool.containsKey(codecClass)) {
List<T> codecList = pool.get(codecClass);
if (codecList != null) {
synchronized (codecList) {
if (!codecList.isEmpty()) {
codec = codecList.remove(codecList.size()-1);
}
}
codecList = pool.get(codecClass);
}
if (codecList != null) {
synchronized (codecList) {
if (!codecList.isEmpty()) {
codec = codecList.remove(codecList.size() - 1);
}
}
}
@ -105,15 +104,17 @@ public class CodecPool {
private static <T> void payback(Map<Class<T>, List<T>> pool, T codec) {
if (codec != null) {
Class<T> codecClass = ReflectionUtils.getClass(codec);
List<T> codecList;
synchronized (pool) {
if (!pool.containsKey(codecClass)) {
pool.put(codecClass, new ArrayList<T>());
codecList = pool.get(codecClass);
if (codecList == null) {
codecList = new ArrayList<T>();
pool.put(codecClass, codecList);
}
}
List<T> codecList = pool.get(codecClass);
synchronized (codecList) {
codecList.add(codec);
}
synchronized (codecList) {
codecList.add(codec);
}
}
}