From 9cd2e3be26a94abf55699b35ba83363a74df8657 Mon Sep 17 00:00:00 2001
From: Vinod Kumar Vavilapalli <vinodkv@apache.org>
Date: Wed, 21 Dec 2011 23:49:39 +0000
Subject: [PATCH] MAPREDUCE-3586. Modified CompositeService to avoid duplicate
 stop operations thereby solving race conditions in MR AM shutdown. (vinodkv)
 svn merge -c 1221950 --ignore-ancestry ../../trunk/

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-0.23@1221951 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-mapreduce-project/CHANGES.txt                   |  4 ++++
 .../apache/hadoop/yarn/service/CompositeService.java   |  4 ++++
 .../apache/hadoop/yarn/util/TestCompositeService.java  | 10 +++++++++-
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 979af1c701e..21001d01f0c 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -303,6 +303,10 @@ Release 0.23.1 - Unreleased
     MAPREDUCE-3349. Log rack-name in JobHistory for unsuccessful tasks. (Amar
     Kamat and Devaraj K via sseth)
 
+    MAPREDUCE-3586. Modified CompositeService to avoid duplicate stop operations
+    thereby solving race conditions in MR AM shutdown. (vinodkv)
+
+>>>>>>> .merge-right.r1221950
 Release 0.23.0 - 2011-11-01 
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/service/CompositeService.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/service/CompositeService.java
index 36fecc38ff8..00cebcfef46 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/service/CompositeService.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/service/CompositeService.java
@@ -81,6 +81,10 @@ public class CompositeService extends AbstractService {
   }
 
   public synchronized void stop() {
+    if (this.getServiceState() == STATE.STOPPED) {
+      // The base composite-service is already stopped, don't do anything again.
+      return;
+    }
     if (serviceList.size() > 0) {
       stop(serviceList.size() - 1);
     }
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestCompositeService.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestCompositeService.java
index 9ca0e4b42c9..7a8aef88f7d 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestCompositeService.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/util/TestCompositeService.java
@@ -88,6 +88,14 @@ public class TestCompositeService {
           ((NUM_OF_SERVICES - 1) - i), services[i].getCallSequenceNumber());
     }
 
+    // Try to stop again. This should be a no-op.
+    serviceManager.stop();
+    // Verify that stop() call sequence numbers for every service don't change.
+    for (int i = 0; i < NUM_OF_SERVICES; i++) {
+      assertEquals("For " + services[i]
+          + " service, stop() call sequence number should have been ",
+          ((NUM_OF_SERVICES - 1) - i), services[i].getCallSequenceNumber());
+    }
   }
 
   @Test
@@ -153,7 +161,7 @@ public class TestCompositeService {
 
     serviceManager.start();
 
-    // Start the composite service
+    // Stop the composite service
     try {
       serviceManager.stop();
     } catch (YarnException e) {