YARN-6175. Negative vcore for resource needed to preempt.

Author: flyrain

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/util/resource/Resources.java

@@ -172,6 +172,24 @@ public static Resource subtract(Resource lhs, Resource rhs) {
     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);
   }

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 @@ private void subtractResourcesOnBlacklistedNodes(
     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);
-    }
   }
 
   /**

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 @@ protected Resource resourceDeficit(FSLeafQueue sched, long curTime) {
     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);