tez git commit: TEZ-2988. DAGAppMaster::shutdownTezAM should return with a no-op if it has been invoked earlier. (Tsuyoshi Ozawa via hitesh)

[hitesh]

Repository: tez
Updated Branches:
  refs/heads/branch-0.7 0c4d0cbfc -> 4b8518aad


TEZ-2988. DAGAppMaster::shutdownTezAM should return with a no-op if it has been 
invoked earlier. (Tsuyoshi Ozawa via hitesh)

(cherry picked from commit dd7919061cd64accb08782d1fc3f58635d64fa72)

Conflicts:
        CHANGES.txt
        tez-dag/src/main/java/org/apache/tez/dag/app/DAGAppMaster.java


Project: http://git-wip-us.apache.org/repos/asf/tez/repo
Commit: http://git-wip-us.apache.org/repos/asf/tez/commit/4b8518aa
Tree: http://git-wip-us.apache.org/repos/asf/tez/tree/4b8518aa
Diff: http://git-wip-us.apache.org/repos/asf/tez/diff/4b8518aa

Branch: refs/heads/branch-0.7
Commit: 4b8518aad686bb937fafbb97fd28c88d603a9e01
Parents: 0c4d0cb
Author: Hitesh Shah <hit...@apache.org>
Authored: Mon Feb 29 10:52:27 2016 -0800
Committer: Hitesh Shah <hit...@apache.org>
Committed: Mon Feb 29 10:54:34 2016 -0800

----------------------------------------------------------------------
 CHANGES.txt                                                    | 1 +
 tez-dag/src/main/java/org/apache/tez/dag/app/DAGAppMaster.java | 6 +++++-
 2 files changed, 6 insertions(+), 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/tez/blob/4b8518aa/CHANGES.txt
----------------------------------------------------------------------
diff --git a/CHANGES.txt b/CHANGES.txt
index df8cf59..96ab0ac 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -9,6 +9,7 @@ INCOMPATIBLE CHANGES
   TEZ-2972. Avoid task rescheduling when a node turns unhealthy
 
 ALL CHANGES:
+  TEZ-2988. DAGAppMaster::shutdownTezAM should return with a no-op if it has 
been invoked earlier.
   TEZ-3147. Intermediate mem-to-mem: Fix early exit when only one segment can 
fit into memory
   TEZ-1911. MergeManager's unconditionalReserve() should check for memory 
limits before allocating.
   TEZ-3141. mapreduce.task.timeout is not translated to container heartbeat 
timeout

http://git-wip-us.apache.org/repos/asf/tez/blob/4b8518aa/tez-dag/src/main/java/org/apache/tez/dag/app/DAGAppMaster.java
----------------------------------------------------------------------
diff --git a/tez-dag/src/main/java/org/apache/tez/dag/app/DAGAppMaster.java 
b/tez-dag/src/main/java/org/apache/tez/dag/app/DAGAppMaster.java
index 5acee83..3a7997b 100644
--- a/tez-dag/src/main/java/org/apache/tez/dag/app/DAGAppMaster.java
+++ b/tez-dag/src/main/java/org/apache/tez/dag/app/DAGAppMaster.java
@@ -1207,7 +1207,11 @@ public class DAGAppMaster extends AbstractService {
   }
 
   public void shutdownTezAM() throws TezException {
-    sessionStopped.set(true);
+    if (!sessionStopped.compareAndSet(false, true)) {
+      // No need to shutdown twice.
+      // Return with a no-op if shutdownTezAM has been invoked earlier.
+      return;
+    }
     synchronized (this) {
       this.taskSchedulerEventHandler.setShouldUnregisterFlag();
       if (currentDAG != null