YARN-881. Priority#compareTo method seems to be wrong. (Jian He via bikas)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1516331 13f79535-47bb-0310-9956-ffa450edef68

hadoop-yarn-project/CHANGES.txt

@@ -80,6 +80,8 @@ Release 2.1.1-beta - UNRELEASED
     YARN-1006. Fixed broken rendering in the Nodes list web page on the RM web
     UI. (Xuan Gong via vinodkv)
 
+    YARN-881. Priority#compareTo method seems to be wrong. (Jian He via bikas)
+
 Release 2.1.0-beta - 2013-08-22
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/Priority.java

@@ -81,7 +81,7 @@ public abstract class Priority implements Comparable<Priority> {
 
   @Override
   public int compareTo(Priority other) {
-    return this.getPriority() - other.getPriority();
+    return other.getPriority() - this.getPriority();
   }
 
   @Override

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java

@@ -385,8 +385,8 @@ public class FairScheduler implements ResourceScheduler {
     // Sort containers into reverse order of priority
     Collections.sort(runningContainers, new Comparator<RMContainer>() {
       public int compare(RMContainer c1, RMContainer c2) {
-        int ret = c2.getContainer().getPriority().compareTo(
-            c1.getContainer().getPriority());
+        int ret = c1.getContainer().getPriority().compareTo(
+            c2.getContainer().getPriority());
         if (ret == 0) {
           return c2.getContainerId().compareTo(c1.getContainerId());
         }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/TestSchedulerUtils.java

@@ -19,6 +19,7 @@
 package org.apache.hadoop.yarn.server.resourcemanager.scheduler;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 import static org.mockito.Mockito.mock;
 
@@ -351,4 +352,10 @@ public class TestSchedulerUtils {
         RMAppAttemptState.LAUNCHED);
   }
 
+  @Test
+  public void testComparePriorities(){
+    Priority high = Priority.newInstance(1);
+    Priority low = Priority.newInstance(2);
+    assertTrue(high.compareTo(low) > 0);
+  }
 }