From 1d156c8758ec3dc45da810d9abaecdb4e811891f Mon Sep 17 00:00:00 2001
From: Karthik Kambatla <kasha@cloudera.com>
Date: Thu, 23 Feb 2017 14:29:30 -0800
Subject: [PATCH] YARN-6175. FairScheduler: Negative vcore for resource needed
 to preempt. (Yufei Gu via kasha)

---
 .../hadoop/yarn/util/resource/Resources.java   | 18 ++++++++++++++++++
 .../scheduler/fair/FSAppAttempt.java           |  8 +-------
 .../scheduler/fair/FairScheduler.java          |  8 ++++----
 3 files changed, 23 insertions(+), 11 deletions(-)

diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/Resources.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/Resources.java
index fdd9ec767aa..d62e55809b5 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/Resources.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/Resources.java
@@ -172,6 +172,24 @@ public class Resources {
     return subtractFrom(clone(lhs), rhs);
   }
 
+  /**
+   * Subtract <code>rhs</code> from <code>lhs</code> and reset any negative
+   * values to zero.
+   * @param lhs {@link Resource} to subtract from
+   * @param rhs {@link Resource} to subtract
+   * @return the value of lhs after subtraction
+   */
+  public static Resource subtractFromNonNegative(Resource lhs, Resource rhs) {
+    subtractFrom(lhs, rhs);
+    if (lhs.getMemorySize() < 0) {
+      lhs.setMemorySize(0);
+    }
+    if (lhs.getVirtualCores() < 0) {
+      lhs.setVirtualCores(0);
+    }
+    return lhs;
+  }
+
   public static Resource negate(Resource resource) {
     return subtract(NONE, resource);
   }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSAppAttempt.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSAppAttempt.java
index 44d2b421f77..802479dd446 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSAppAttempt.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FSAppAttempt.java
@@ -194,16 +194,10 @@ public class FSAppAttempt extends SchedulerApplicationAttempt
     for (NodeId nodeId: blacklistNodeIds) {
       SchedulerNode node = scheduler.getSchedulerNode(nodeId);
       if (node != null) {
-        Resources.subtractFrom(availableResources,
+        Resources.subtractFromNonNegative(availableResources,
             node.getAvailableResource());
       }
     }
-    if (availableResources.getMemory() < 0) {
-      availableResources.setMemory(0);
-    }
-    if (availableResources.getVirtualCores() < 0) {
-      availableResources.setVirtualCores(0);
-    }
   }
 
   /**
diff --git a/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 b/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
index 1586a49fa2a..8e7d299a4e3 100644
--- a/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
+++ b/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
@@ -531,14 +531,14 @@ public class FairScheduler extends
     if (curTime - sched.getLastTimeAtMinShare() > minShareTimeout) {
       Resource target = Resources.componentwiseMin(
           sched.getMinShare(), sched.getDemand());
-      resDueToMinShare = Resources.max(calc, clusterResource,
-          Resources.none(), Resources.subtract(target, sched.getResourceUsage()));
+      resDueToMinShare =
+          Resources.subtractFromNonNegative(target, sched.getResourceUsage());
     }
     if (curTime - sched.getLastTimeAtFairShareThreshold() > fairShareTimeout) {
       Resource target = Resources.componentwiseMin(
               sched.getFairShare(), sched.getDemand());
-      resDueToFairShare = Resources.max(calc, clusterResource,
-          Resources.none(), Resources.subtract(target, sched.getResourceUsage()));
+      resDueToFairShare =
+          Resources.subtractFromNonNegative(target, sched.getResourceUsage());
     }
     Resource deficit = Resources.max(calc, clusterResource,
         resDueToMinShare, resDueToFairShare);