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Posted to yarn-commits@hadoop.apache.org by vi...@apache.org on 2013/12/31 02:10:30 UTC
svn commit: r1554345 -
/hadoop/common/branches/branch-2/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/event/AsyncDispatcher.java
Author: vinodkv
Date: Tue Dec 31 01:10:29 2013
New Revision: 1554345
URL: http://svn.apache.org/r1554345
Log:
YARN-1121. Addendum patch. Fixed AsyncDispatcher hang issue during stop due to a race condition caused by the previous patch. Contributed by Jian He.
svn merge --ignore-ancestry -c 1554344 ../../trunk/
Modified:
hadoop/common/branches/branch-2/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/event/AsyncDispatcher.java
Modified: hadoop/common/branches/branch-2/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/event/AsyncDispatcher.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/branch-2/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/event/AsyncDispatcher.java?rev=1554345&r1=1554344&r2=1554345&view=diff
==============================================================================
--- hadoop/common/branches/branch-2/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/event/AsyncDispatcher.java (original)
+++ hadoop/common/branches/branch-2/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/event/AsyncDispatcher.java Tue Dec 31 01:10:29 2013
@@ -56,6 +56,7 @@ public class AsyncDispatcher extends Abs
// Indicates all the remaining dispatcher's events on stop have been drained
// and processed.
private volatile boolean drained = true;
+ private Object waitForDrained = new Object();
// For drainEventsOnStop enabled only, block newly coming events into the
// queue while stopping.
@@ -82,6 +83,16 @@ public class AsyncDispatcher extends Abs
public void run() {
while (!stopped && !Thread.currentThread().isInterrupted()) {
drained = eventQueue.isEmpty();
+ // blockNewEvents is only set when dispatcher is draining to stop,
+ // adding this check is to avoid the overhead of acquiring the lock
+ // and calling notify every time in the normal run of the loop.
+ if (blockNewEvents) {
+ synchronized (waitForDrained) {
+ if (drained) {
+ waitForDrained.notify();
+ }
+ }
+ }
Event event;
try {
event = eventQueue.take();
@@ -125,8 +136,11 @@ public class AsyncDispatcher extends Abs
if (drainEventsOnStop) {
blockNewEvents = true;
LOG.info("AsyncDispatcher is draining to stop, igonring any new events.");
- while(!drained) {
- Thread.yield();
+ synchronized (waitForDrained) {
+ while (!drained && eventHandlingThread.isAlive()) {
+ waitForDrained.wait(1000);
+ LOG.info("Waiting for AsyncDispatcher to drain.");
+ }
}
}
stopped = true;