diff --git a/gc/base/Collector.hpp b/gc/base/Collector.hpp
index 3cccf07faf3..ce2baacddc9 100644
--- a/gc/base/Collector.hpp
+++ b/gc/base/Collector.hpp
@@ -194,7 +194,7 @@ class MM_Collector : public MM_BaseVirtual
 	 * moved from one subspace to another.
 	 * @param env[in] The thread which performed the change in heap geometry 
 	 */
-	virtual void heapReconfigured(MM_EnvironmentBase* env) = 0;
+	virtual void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL) = 0;
 
 	/**
 	 * Post collection broadcast event, indicating that the collection has been completed.
diff --git a/gc/base/GCExtensionsBase.hpp b/gc/base/GCExtensionsBase.hpp
index 7bcb19fa15a..fc1ed873dcb 100644
--- a/gc/base/GCExtensionsBase.hpp
+++ b/gc/base/GCExtensionsBase.hpp
@@ -1509,7 +1509,7 @@ class MM_GCExtensionsBase : public MM_BaseVirtual {
 #if defined(OMR_GC_CONCURRENT_SCAVENGER)
 		, softwareRangeCheckReadBarrier(false)
 		, concurrentScavenger(false)
-		, concurrentScavengerForced(false)
+		, concurrentScavengerForced(true)
 		, concurrentScavengerHWSupport(false)
 		, concurrentScavengerBackgroundThreads(1)
 		, concurrentScavengerBackgroundThreadsForced(false)
diff --git a/gc/base/Heap.cpp b/gc/base/Heap.cpp
index a066e537fc5..ac7235e9e37 100644
--- a/gc/base/Heap.cpp
+++ b/gc/base/Heap.cpp
@@ -433,12 +433,12 @@ MM_Heap::heapRemoveRange(MM_EnvironmentBase* env, MM_MemorySubSpace* subspace, u
  * The heap has had its memory shuffled between memory subspaces and/or memory pools.
  */
 void
-MM_Heap::heapReconfigured(MM_EnvironmentBase* env)
+MM_Heap::heapReconfigured(MM_EnvironmentBase* env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
 	MM_GlobalCollector* globalCollector = env->getExtensions()->getGlobalCollector();
 
 	if (NULL != globalCollector) {
-		globalCollector->heapReconfigured(env);
+		globalCollector->heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 	}
 }
 
diff --git a/gc/base/Heap.hpp b/gc/base/Heap.hpp
index 052d5018c69..840a8fbf830 100644
--- a/gc/base/Heap.hpp
+++ b/gc/base/Heap.hpp
@@ -148,7 +148,7 @@ class MM_Heap : public MM_BaseVirtual
 	 * moved from one subspace to another.
 	 * @param env[in] The thread which performed the change in heap geometry 
 	 */
-	virtual void heapReconfigured(MM_EnvironmentBase *env);
+	virtual void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 	virtual bool objectIsInGap(void *object);
 
diff --git a/gc/base/MemorySpace.cpp b/gc/base/MemorySpace.cpp
index bf534843fe5..75722d50f09 100644
--- a/gc/base/MemorySpace.cpp
+++ b/gc/base/MemorySpace.cpp
@@ -515,9 +515,9 @@ MM_MemorySpace::heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subs
  * 
  */
 void
-MM_MemorySpace::heapReconfigured(MM_EnvironmentBase *env)
+MM_MemorySpace::heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
-	_heap->heapReconfigured(env);
+	_heap->heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 }
 
 /**
diff --git a/gc/base/MemorySpace.hpp b/gc/base/MemorySpace.hpp
index 31982480a20..892f79f950f 100644
--- a/gc/base/MemorySpace.hpp
+++ b/gc/base/MemorySpace.hpp
@@ -181,7 +181,7 @@ class MM_MemorySpace : public MM_BaseVirtual
 	 * moved from one subspace to another.
 	 * @param env[in] The thread which performed the change in heap geometry 
 	 */
-	void heapReconfigured(MM_EnvironmentBase *env);
+	void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 	static MM_MemorySpace *getMemorySpace(void *memorySpace) { return (MM_MemorySpace *)memorySpace; }
 
diff --git a/gc/base/MemorySubSpace.cpp b/gc/base/MemorySubSpace.cpp
index 2eaa7e855f4..9188eaaa977 100644
--- a/gc/base/MemorySubSpace.cpp
+++ b/gc/base/MemorySubSpace.cpp
@@ -1380,16 +1380,16 @@ MM_MemorySubSpace::heapRemoveRange(MM_EnvironmentBase* env, MM_MemorySubSpace* s
  * 
  */
 void
-MM_MemorySubSpace::heapReconfigured(MM_EnvironmentBase* env)
+MM_MemorySubSpace::heapReconfigured(MM_EnvironmentBase* env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
 	if (!_usesGlobalCollector && (NULL != _collector)) {
-		_collector->heapReconfigured(env);
+		_collector->heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 	}
 
 	if (_parent) {
-		_parent->heapReconfigured(env);
+		_parent->heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 	} else if (_memorySpace) {
-		_memorySpace->heapReconfigured(env);
+		_memorySpace->heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 	}
 }
 
diff --git a/gc/base/MemorySubSpace.hpp b/gc/base/MemorySubSpace.hpp
index ebed5efefd7..46c993d78cb 100644
--- a/gc/base/MemorySubSpace.hpp
+++ b/gc/base/MemorySubSpace.hpp
@@ -404,7 +404,7 @@ friend class GC_MemorySubSpaceRegionIterator;
 	 * moved from one subspace to another.
 	 * @param env[in] The thread which performed the change in heap geometry 
 	 */
-	virtual void heapReconfigured(MM_EnvironmentBase *env);
+	virtual void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 	virtual void *findFreeEntryEndingAtAddr(MM_EnvironmentBase *env, void *addr);
 	virtual void *findFreeEntryTopStartingAtAddr(MM_EnvironmentBase *env, void *addr);
diff --git a/gc/base/PhysicalSubArenaVirtualMemoryFlat.cpp b/gc/base/PhysicalSubArenaVirtualMemoryFlat.cpp
index 3546ded98e9..1d3c3b35979 100644
--- a/gc/base/PhysicalSubArenaVirtualMemoryFlat.cpp
+++ b/gc/base/PhysicalSubArenaVirtualMemoryFlat.cpp
@@ -94,7 +94,7 @@ MM_PhysicalSubArenaVirtualMemoryFlat::tearDown(MM_EnvironmentBase *env)
 	}
 	if (NULL != _subSpace) {
 		_subSpace->heapRemoveRange(env, _subSpace, ((uintptr_t)_highAddress) - ((uintptr_t)_lowAddress), _lowAddress, _highAddress, lowValidAddress, highValidAddress);
-		_subSpace->heapReconfigured(env);
+		_subSpace->heapReconfigured(env, RECONFIG_CONTRACT);
 	}
 	MM_PhysicalSubArenaVirtualMemory::tearDown(env);
 }
@@ -113,9 +113,17 @@ MM_PhysicalSubArenaVirtualMemoryFlat::inflate(MM_EnvironmentBase *env)
 		if(NULL != _region) {
 			Assert_MM_true((_lowAddress == _region->getLowAddress()) && (_highAddress == _region->getHighAddress()));
 			/* Inflation successful - inform the owning memorySubSpace */
-			//TODO: Like the semi space arena, this should dispatch directory to the child subspace
-			result = _subSpace->expanded(env, this, _region->getSize(), _region->getLowAddress(), _region->getHighAddress(), false);
-			_subSpace->heapReconfigured(env);
+
+			void *lowAddress = _region->getLowAddress();
+			void *highAddress = _region->getHighAddress();
+
+			MM_MemorySubSpace *genericSubSpace = ((MM_MemorySubSpaceFlat *)_subSpace)->getChildSubSpace();
+			result = genericSubSpace->expanded(env, this, _region->getSize(), lowAddress, highAddress, false);
+			if (result) {
+				_subSpace->heapReconfigured(env, RECONFIG_EXPAND, genericSubSpace, lowAddress, highAddress);
+			} else {
+				_subSpace->heapReconfigured(env, RECONFIG_EXPAND);
+			}
 		}
 	}
 	return result;
@@ -211,11 +219,12 @@ MM_PhysicalSubArenaVirtualMemoryFlat::expandNoCheck(MM_EnvironmentBase *env, uin
 		getHeapRegionManager()->resizeAuxillaryRegion(env, _region, _lowAddress, _highAddress);
 		Assert_MM_true(NULL != _region);
 
-		if(result){
+		if(result) {
 			genericSubSpace->addExistingMemory(env, this, expandSize, lowExpandAddress, highExpandAddress, true);
+			_subSpace->heapReconfigured(env, RECONFIG_EXPAND, genericSubSpace, lowExpandAddress, highExpandAddress);
+		} else {
+			_subSpace->heapReconfigured(env, RECONFIG_EXPAND);
 		}
-
-		_subSpace->heapReconfigured(env);
 	}
 
 	Assert_MM_true(_lowAddress == _region->getLowAddress());
@@ -305,10 +314,9 @@ MM_PhysicalSubArenaVirtualMemoryFlat::contract(MM_EnvironmentBase *env, uintptr_
 	_highAddress = (void *)contractBase;
 	getHeapRegionManager()->resizeAuxillaryRegion(env, _region, _lowAddress, _highAddress);
 	Assert_MM_true(NULL != _region);
-
 	/* Broadcast that heap has been removed */
 	genericSubSpace->heapRemoveRange(env, _subSpace, contractSize, (void *)contractBase, (void *)contractTop, lowValidAddress, highValidAddress);
-	genericSubSpace->heapReconfigured(env);
+	genericSubSpace->heapReconfigured(env, RECONFIG_CONTRACT);
 
 	/* Execute any pending counter balances to the contract that have been enqueued */
 	_subSpace->triggerEnqueuedCounterBalancing(env);
diff --git a/gc/base/segregated/MemorySubSpaceSegregated.cpp b/gc/base/segregated/MemorySubSpaceSegregated.cpp
index e5090179eee..9cc8e61aac2 100644
--- a/gc/base/segregated/MemorySubSpaceSegregated.cpp
+++ b/gc/base/segregated/MemorySubSpaceSegregated.cpp
@@ -310,9 +310,9 @@ MM_MemorySubSpaceSegregated::heapRemoveRange(MM_EnvironmentBase *env, MM_MemoryS
 }
 
 void
-MM_MemorySubSpaceSegregated::heapReconfigured(MM_EnvironmentBase *env)
+MM_MemorySubSpaceSegregated::heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
-	MM_MemorySubSpaceUniSpace::heapReconfigured(env);
+	MM_MemorySubSpaceUniSpace::heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 	if (_regionExpansionBase != _regionExpansionTop) {
 		expandRegionPool();
 	}
diff --git a/gc/base/segregated/MemorySubSpaceSegregated.hpp b/gc/base/segregated/MemorySubSpaceSegregated.hpp
index 03c9b91db15..a5493097efe 100644
--- a/gc/base/segregated/MemorySubSpaceSegregated.hpp
+++ b/gc/base/segregated/MemorySubSpaceSegregated.hpp
@@ -114,7 +114,7 @@ class MM_MemorySubSpaceSegregated : public MM_MemorySubSpaceUniSpace
 
 	virtual bool heapAddRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspace, uintptr_t size, void *lowAddress, void *highAddress);
 	virtual bool heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspace, uintptr_t size, void *lowAddress, void *highAddress, void *lowValidAddress, void *highValidAddress);
-	virtual void heapReconfigured(MM_EnvironmentBase *env);
+	virtual void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 	virtual MM_MemoryPool *getMemoryPool();
 	
diff --git a/gc/base/segregated/SegregatedGC.cpp b/gc/base/segregated/SegregatedGC.cpp
index 2bd3a369350..be1637fa95c 100644
--- a/gc/base/segregated/SegregatedGC.cpp
+++ b/gc/base/segregated/SegregatedGC.cpp
@@ -126,7 +126,7 @@ MM_SegregatedGC::heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpace *sub
 	return _markingScheme->heapRemoveRange(env, subspace, size, lowAddress, highAddress, lowValidAddress, highValidAddress);
 }
 
-void MM_SegregatedGC::heapReconfigured(MM_EnvironmentBase* env)
+void MM_SegregatedGC::heapReconfigured(MM_EnvironmentBase* env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
 	/* OMRTODO implement proper heap resizing in segregated heaps */
 }
diff --git a/gc/base/segregated/SegregatedGC.hpp b/gc/base/segregated/SegregatedGC.hpp
index 3c8a9845fe8..8f5dd525858 100644
--- a/gc/base/segregated/SegregatedGC.hpp
+++ b/gc/base/segregated/SegregatedGC.hpp
@@ -96,7 +96,7 @@ class MM_SegregatedGC : public MM_GlobalCollector
 
 	virtual bool heapAddRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspace, uintptr_t size, void *lowAddress, void *highAddress);
 	virtual bool heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspace,uintptr_t size, void *lowAddress, void *highAddress, void *lowValidAddress, void *highValidAddress);
-	virtual void heapReconfigured(MM_EnvironmentBase* env);
+	virtual void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 	virtual bool isMarked(void *objectPtr) { return _markingScheme->isMarked(static_cast<omrobjectptr_t>(objectPtr)); }
 
diff --git a/gc/base/standard/ConcurrentCardTable.cpp b/gc/base/standard/ConcurrentCardTable.cpp
index ea74a43c628..a6116c985f2 100644
--- a/gc/base/standard/ConcurrentCardTable.cpp
+++ b/gc/base/standard/ConcurrentCardTable.cpp
@@ -416,7 +416,7 @@ MM_ConcurrentCardTable::heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpa
  *
  */
 void
-MM_ConcurrentCardTable::heapReconfigured(MM_EnvironmentBase *env)
+MM_ConcurrentCardTable::heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
 }
 
diff --git a/gc/base/standard/ConcurrentCardTable.hpp b/gc/base/standard/ConcurrentCardTable.hpp
index c65558d9b43..95513ff007f 100644
--- a/gc/base/standard/ConcurrentCardTable.hpp
+++ b/gc/base/standard/ConcurrentCardTable.hpp
@@ -325,7 +325,7 @@ class MM_ConcurrentCardTable : public MM_CardTable
 	 * @param[in] env The thread which caused the heap geometry change (typically the master GC thread)
 	 * @note This implementation does nothing.
 	 */
-	void heapReconfigured(MM_EnvironmentBase *env);
+	void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 	
 	/**
 	 * @return A pointer to the mutable card table stats structure
diff --git a/gc/base/standard/ConcurrentGC.cpp b/gc/base/standard/ConcurrentGC.cpp
index 06363449601..21b670f6c85 100644
--- a/gc/base/standard/ConcurrentGC.cpp
+++ b/gc/base/standard/ConcurrentGC.cpp
@@ -3267,23 +3267,6 @@ MM_ConcurrentGC::heapAddRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspa
 	/* Expand any superclass structures including mark bits*/
 	bool result = MM_ParallelGlobalGC::heapAddRange(env, subspace, size, lowAddress, highAddress);
 
-	if (result) {
-		/* If we are within a concurrent cycle we need to initialize the mark bits
-		 * for new region of heap now
-		 */
-		if (CONCURRENT_OFF < _stats.getExecutionMode()) {
-			/* If subspace is concurrently collectible then clear bits otherwise
-			 * set the bits on to stop tracing INTO this area during concurrent
-			 * mark cycle.
-			 */
-			if (subspace->isConcurrentCollectable()) {
-				_markingScheme->setMarkBitsInRange(env, lowAddress, highAddress, true);
-			} else {
-				_markingScheme->setMarkBitsInRange(env, lowAddress, highAddress, false);
-			}
-		}
-	}
-
 	_heapAlloc = _extensions->heap->getHeapTop();
 
 	Trc_MM_ConcurrentGC_heapAddRange_Exit(env->getLanguageVMThread());
@@ -3329,34 +3312,57 @@ MM_ConcurrentGC::heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpace *sub
  * @see MM_ParallelGlobalGC::heapReconfigured()
  */
 void
-MM_ConcurrentGC::heapReconfigured(MM_EnvironmentBase *env)
+MM_ConcurrentGC::heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
-	/* If called outside a global collection for a heap expand/contract..
-	 */
-	if (!_stwCollectionInProgress && (_rebuildInitWorkForAdd || _rebuildInitWorkForRemove)) {
-		/* ... and a concurrent cycle has not yet started then we
-		 *  tune to heap here to reflect new heap size
-		 *  Note: CMVC 153167 : Under gencon, there is a timing hole where
-		 *  if we are in the middle of initializing the heap ranges while a
-		 *  scavenge occurs, and if the scavenge causes the heap to contract,
-		 *  we will try to memset ranges that are now contracted (decommitted memory)
-		 *  when we resume the init work.
+	Assert_MM_true(reason != RECONFIG_NONE);
+
+	if (lowAddress != NULL && highAddress != NULL) {
+		Assert_MM_true(_rebuildInitWorkForAdd && reason == RECONFIG_EXPAND);
+		/* If we are within a concurrent cycle we need to initialize the mark bits
+		 * for new region of heap now
 		 */
-		if (_stats.getExecutionMode() < CONCURRENT_INIT_COMPLETE) {
-			tuneToHeap(env);
-		} else {
-			/* Heap expand/contract is during a concurrent cycle..we need to adjust the trace target so
-			 * that the trace rate is adjusted correctly on  subsequent allocates.
+		if (CONCURRENT_OFF < _stats.getExecutionMode()) {
+			/* If subspace is concurrently collectible then clear bits otherwise
+			 * set the bits on to stop tracing INTO this area during concurrent
+			 * mark cycle.
 			 */
-			adjustTraceTarget();
+			if (subspace->isConcurrentCollectable()) {
+				_markingScheme->setMarkBitsInRange(env, lowAddress, highAddress, true);
+			} else {
+				_markingScheme->setMarkBitsInRange(env, lowAddress, highAddress, false);
+			}
 		}
 	}
 
+	/* If called outside a global collection for a heap expand/contract.. */
+	if(reason == RECONFIG_CONTRACT || reason == RECONFIG_EXPAND) {
+		Assert_MM_true(_rebuildInitWorkForAdd || _rebuildInitWorkForRemove);
+		if (!_stwCollectionInProgress) {
+			/* ... and a concurrent cycle has not yet started then we
+			 *  tune to heap here to reflect new heap size
+			 *  Note: CMVC 153167 : Under gencon, there is a timing hole where
+			 *  if we are in the middle of initializing the heap ranges while a
+			 *  scavenge occurs, and if the scavenge causes the heap to contract,
+			 *  we will try to memset ranges that are now contracted (decommitted memory)
+			 *  when we resume the init work.
+			 */
+			if (_stats.getExecutionMode() < CONCURRENT_INIT_COMPLETE) {
+				tuneToHeap(env);
+			} else {
+				/* Heap expand/contract is during a concurrent cycle..we need to adjust the trace target so
+				 * that the trace rate is adjusted correctly on  subsequent allocates.
+				 */
+				adjustTraceTarget();
+			}
+		}
+	}
+
+
 	/* Expand any superclass structures */
-	MM_ParallelGlobalGC::heapReconfigured(env);
+	MM_ParallelGlobalGC::heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 
 	/* ...and then expand the card table */
-	((MM_ConcurrentCardTable *)_cardTable)->heapReconfigured(env);
+	((MM_ConcurrentCardTable *)_cardTable)->heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 }
 
 /**
diff --git a/gc/base/standard/ConcurrentGC.hpp b/gc/base/standard/ConcurrentGC.hpp
index 05354dcd906..e9b248a0cda 100644
--- a/gc/base/standard/ConcurrentGC.hpp
+++ b/gc/base/standard/ConcurrentGC.hpp
@@ -426,7 +426,7 @@ class MM_ConcurrentGC : public MM_ParallelGlobalGC
 	
 	virtual bool heapAddRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspace, uintptr_t size, void *lowAddress, void *highAddress);
 	virtual bool heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspace, uintptr_t size, void *lowAddress, void *highAddress, void *lowValidAddress, void *highValidAddress);
-	virtual void heapReconfigured(MM_EnvironmentBase *env);
+	virtual void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 	void finalCleanCards(MM_EnvironmentBase *env);
 
diff --git a/gc/base/standard/ConcurrentGCIncrementalUpdate.cpp b/gc/base/standard/ConcurrentGCIncrementalUpdate.cpp
index ce30763dc0b..3273f65f29b 100644
--- a/gc/base/standard/ConcurrentGCIncrementalUpdate.cpp
+++ b/gc/base/standard/ConcurrentGCIncrementalUpdate.cpp
@@ -124,7 +124,6 @@ MM_ConcurrentGCIncrementalUpdate::heapAddRange(MM_EnvironmentBase *env, MM_Memor
 
 	/* Expand any superclass structures including mark bits*/
 	bool result = MM_ConcurrentGC::heapAddRange(env, subspace, size, lowAddress, highAddress);
-
 	if (result) {
 		/* expand the card table */
 		result = ((MM_ConcurrentCardTable *)_cardTable)->heapAddRange(env, subspace, size, lowAddress, highAddress, clearCards);
diff --git a/gc/base/standard/ParallelGlobalGC.cpp b/gc/base/standard/ParallelGlobalGC.cpp
index d6727a6d02d..09282ee8fd5 100644
--- a/gc/base/standard/ParallelGlobalGC.cpp
+++ b/gc/base/standard/ParallelGlobalGC.cpp
@@ -1345,9 +1345,9 @@ MM_ParallelGlobalGC::heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpace
  * @see MM_GlobalCollector::heapReconfigured()
  */
 void
-MM_ParallelGlobalGC::heapReconfigured(MM_EnvironmentBase *env)
+MM_ParallelGlobalGC::heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
-	_sweepScheme->heapReconfigured(env);
+	_sweepScheme->heapReconfigured(env, reason, subspace, lowAddress, highAddress);
 	
 }
 
diff --git a/gc/base/standard/ParallelGlobalGC.hpp b/gc/base/standard/ParallelGlobalGC.hpp
index 0f9e815eb81..52bff889721 100644
--- a/gc/base/standard/ParallelGlobalGC.hpp
+++ b/gc/base/standard/ParallelGlobalGC.hpp
@@ -289,7 +289,7 @@ class MM_ParallelGlobalGC : public MM_GlobalCollector
 
 	virtual bool heapAddRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspace, uintptr_t size, void *lowAddress, void *highAddress);
 	virtual bool heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpace *subspace, uintptr_t size, void *lowAddress, void *highAddress, void *lowValidAddress, void *highValidAddress);
-	virtual void heapReconfigured(MM_EnvironmentBase *env);
+	virtual void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 	virtual	uint32_t getGCTimePercentage(MM_EnvironmentBase *env);
 
diff --git a/gc/base/standard/ParallelSweepScheme.cpp b/gc/base/standard/ParallelSweepScheme.cpp
index e4272e4aa50..e3752e8edcd 100644
--- a/gc/base/standard/ParallelSweepScheme.cpp
+++ b/gc/base/standard/ParallelSweepScheme.cpp
@@ -305,7 +305,7 @@ MM_ParallelSweepScheme::heapRemoveRange(MM_EnvironmentBase *env, MM_MemorySubSpa
  * 
  */
 void
-MM_ParallelSweepScheme::heapReconfigured(MM_EnvironmentBase *env)
+MM_ParallelSweepScheme::heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
 	_sweepHeapSectioning->update(env);
 }
diff --git a/gc/base/standard/ParallelSweepScheme.hpp b/gc/base/standard/ParallelSweepScheme.hpp
index 567ce6f32d3..b86f05f217c 100644
--- a/gc/base/standard/ParallelSweepScheme.hpp
+++ b/gc/base/standard/ParallelSweepScheme.hpp
@@ -187,7 +187,7 @@ class MM_ParallelSweepScheme : public MM_BaseVirtual
 	 * moved from one subspace to another.
 	 * @param env[in] The thread which performed the change in heap geometry 
 	 */
-	void heapReconfigured(MM_EnvironmentBase *env);
+	void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 #if defined(OMR_GC_CONCURRENT_SWEEP)
 	virtual bool replenishPoolForAllocate(MM_EnvironmentBase *env, MM_MemoryPool *memoryPool, uintptr_t size);
diff --git a/gc/base/standard/PhysicalSubArenaVirtualMemorySemiSpace.cpp b/gc/base/standard/PhysicalSubArenaVirtualMemorySemiSpace.cpp
index 5351daf9baa..de00d3d01c6 100644
--- a/gc/base/standard/PhysicalSubArenaVirtualMemorySemiSpace.cpp
+++ b/gc/base/standard/PhysicalSubArenaVirtualMemorySemiSpace.cpp
@@ -114,7 +114,7 @@ MM_PhysicalSubArenaVirtualMemorySemiSpace::tearDown(MM_EnvironmentBase *env)
 	/* Remove the heap range represented */
 	if (NULL != _subSpace) {
 		_subSpace->heapRemoveRange(env, _subSpace, ((uintptr_t)_highAddress) - ((uintptr_t)_lowAddress), _lowAddress, _highAddress, lowValidAddress, highValidAddress);
-		_subSpace->heapReconfigured(env);
+		_subSpace->heapReconfigured(env, RECONFIG_CONTRACT);
 	}
 	MM_PhysicalSubArenaVirtualMemory::tearDown(env);
 }
@@ -188,12 +188,30 @@ MM_PhysicalSubArenaVirtualMemorySemiSpace::inflate(MM_EnvironmentBase *env)
 			Assert_MM_inflateInvalidRange();
 		}
 
+		void *lowAddress = _highSemiSpaceRegion->getLowAddress();
+		void *highAddress = _highSemiSpaceRegion->getHighAddress();
+
 		/* Inform the semi spaces that they have been expanded */
-		bool result = subSpaceAllocate->expanded(env, this, _highSemiSpaceRegion->getSize(), _highSemiSpaceRegion->getLowAddress(), _highSemiSpaceRegion->getHighAddress(), false);
-		subSpaceAllocate->heapReconfigured(env);
-		result = result && subSpaceSurvivor->expanded(env, this, _lowSemiSpaceRegion->getSize(), _lowSemiSpaceRegion->getLowAddress(), _lowSemiSpaceRegion->getHighAddress(), false);
-		subSpaceSurvivor->heapReconfigured(env);
-		return result;
+		bool resultExpandAllocate = subSpaceAllocate->expanded(env, this, _highSemiSpaceRegion->getSize(), lowAddress, highAddress, false);
+
+		if (resultExpandAllocate) {
+			subSpaceAllocate->heapReconfigured(env, RECONFIG_EXPAND, subSpaceAllocate, lowAddress, highAddress);
+		} else {
+			subSpaceAllocate->heapReconfigured(env, RECONFIG_EXPAND);
+		}
+
+		lowAddress = _lowSemiSpaceRegion->getLowAddress();
+		highAddress = _lowSemiSpaceRegion->getHighAddress();
+
+		bool resultExpandSurvivor = subSpaceSurvivor->expanded(env, this, _lowSemiSpaceRegion->getSize(), lowAddress, highAddress, false);
+
+		if(resultExpandSurvivor) {
+			subSpaceSurvivor->heapReconfigured(env, RECONFIG_EXPAND, subSpaceSurvivor, lowAddress, highAddress);
+		} else {
+			subSpaceSurvivor->heapReconfigured(env, RECONFIG_EXPAND);
+		}
+
+		return resultExpandAllocate && resultExpandSurvivor;
 	}
 	return false;
 }
@@ -686,7 +704,7 @@ MM_PhysicalSubArenaVirtualMemorySemiSpace::contract(MM_EnvironmentBase *env, uin
 			removeMemoryTop,
 			previousValidAddressNotRemoved,
 			(void *)allocateSegmentBase);
-		_subSpace->heapReconfigured(env);
+		_subSpace->heapReconfigured(env, RECONFIG_CONTRACT);
 
 		/* Decommit the heap (the return value really doesn't matter here - its already too late) */
 		_heap->decommitMemory(
@@ -869,7 +887,7 @@ MM_PhysicalSubArenaVirtualMemorySemiSpace::contract(MM_EnvironmentBase *env, uin
 			removeMemoryTop,
 			previousValidAddressNotRemoved,
 			(void *)survivorSegmentBase);
-		_subSpace->heapReconfigured(env);
+		_subSpace->heapReconfigured(env, RECONFIG_CONTRACT);
 
 		/* Decommit the heap (the return value really doesn't matter here - its already too late) */
 		_heap->decommitMemory(
@@ -1046,7 +1064,7 @@ MM_PhysicalSubArenaVirtualMemorySemiSpace::tilt(MM_EnvironmentBase *env, uintptr
 	((MM_MemorySubSpaceSemiSpace *)_subSpace)->setSurvivorSpaceSizeRatio(survivorSpaceSize / ((_highSemiSpaceRegion->getSize() + _lowSemiSpaceRegion->getSize()) / 100));
 
 	/* Broadcast that the heap has been reconfigured */
-	_subSpace->heapReconfigured(env);
+	_subSpace->heapReconfigured(env, RECONFIG_SCAVENGER_TILT);
 }
 
 /**
@@ -1253,8 +1271,12 @@ MM_PhysicalSubArenaVirtualMemorySemiSpace::expandNoCheck(MM_EnvironmentBase *env
 		/* Broadcast the expansion of the heap, but do not add the memory to any free lists.
 		 * Must be done after segment information has been updated.
 		 */
-		_subSpace->heapAddRange(env, _subSpace, splitExpandSize, newLowAddress, (void *) (((uintptr_t)newLowAddress) + splitExpandSize));
-		_subSpace->heapReconfigured(env);
+		bool expandResult = _subSpace->heapAddRange(env, _subSpace, splitExpandSize, newLowAddress, (void *) (((uintptr_t)newLowAddress) + splitExpandSize));
+		if (expandResult) {
+			_subSpace->heapReconfigured(env, RECONFIG_EXPAND, _subSpace, newLowAddress, (void *) (((uintptr_t)newLowAddress) + splitExpandSize));
+		} else {
+			_subSpace->heapReconfigured(env, RECONFIG_EXPAND);
+		}
 		
 		/* Include the memory into the free lists */
 		if(debug) {
@@ -1315,8 +1337,12 @@ MM_PhysicalSubArenaVirtualMemorySemiSpace::expandNoCheck(MM_EnvironmentBase *env
 		/* Broadcast the expansion of the heap, but do not add the memory to any free lists.
 		 * Must be done after segment information has been updated.
 		 */
-		_subSpace->heapAddRange(env, _subSpace, splitExpandSize, newLowAddress, (void *) (((uintptr_t)newLowAddress) + splitExpandSize));
-		_subSpace->heapReconfigured(env);
+		bool expandResult = _subSpace->heapAddRange(env, _subSpace, splitExpandSize, newLowAddress, (void *) (((uintptr_t)newLowAddress) + splitExpandSize));
+		if (expandResult) {
+			_subSpace->heapReconfigured(env, RECONFIG_EXPAND, _subSpace, newLowAddress, (void *) (((uintptr_t)newLowAddress) + splitExpandSize));
+		} else {
+			_subSpace->heapReconfigured(env, RECONFIG_EXPAND);
+		}
 
 		/* Include the memory into the free lists. */
 		if(debug) {
diff --git a/gc/base/standard/Scavenger.cpp b/gc/base/standard/Scavenger.cpp
index a55f47228a2..d6877322cbc 100644
--- a/gc/base/standard/Scavenger.cpp
+++ b/gc/base/standard/Scavenger.cpp
@@ -4435,7 +4435,7 @@ MM_Scavenger::percolateGarbageCollect(MM_EnvironmentBase *env,  MM_MemorySubSpac
  *
  */
 void
-MM_Scavenger::heapReconfigured(MM_EnvironmentBase *env)
+MM_Scavenger::heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason, MM_MemorySubSpace *subspace, void *lowAddress, void *highAddress)
 {
 }
 
diff --git a/gc/base/standard/Scavenger.hpp b/gc/base/standard/Scavenger.hpp
index 6d907f991a9..6effb60496a 100644
--- a/gc/base/standard/Scavenger.hpp
+++ b/gc/base/standard/Scavenger.hpp
@@ -815,7 +815,7 @@ class MM_Scavenger : public MM_Collector
 	virtual bool canCollectorExpand(MM_EnvironmentBase *env, MM_MemorySubSpace *subSpace, uintptr_t expandSize);
 	virtual uintptr_t getCollectorExpandSize(MM_EnvironmentBase *env);
 
-	virtual void heapReconfigured(MM_EnvironmentBase *env);
+	virtual void heapReconfigured(MM_EnvironmentBase *env, HeapReconfigReason reason = RECONFIG_NONE, MM_MemorySubSpace *subspace = NULL, void *lowAddress = NULL, void *highAddress = NULL);
 
 	MM_Scavenger(MM_EnvironmentBase *env, MM_HeapRegionManager *regionManager) :
 		MM_Collector()
diff --git a/gc/startup/omrgcstartup.cpp b/gc/startup/omrgcstartup.cpp
index ece3778353a..1b4ccaba8bf 100644
--- a/gc/startup/omrgcstartup.cpp
+++ b/gc/startup/omrgcstartup.cpp
@@ -283,7 +283,7 @@ OMR_GC_InitializeCollector(OMR_VMThread* omrVMThread)
 			}
 
 			/* Make sure sweep scheme is up-to-date with the heap configuration */
-			globalCollector->heapReconfigured(env);
+			globalCollector->heapReconfigured(env, RECONFIG_EXPAND);
 		}
 	}
 
diff --git a/include_core/omrgcconsts.h b/include_core/omrgcconsts.h
index 87e1471d9a8..496efa4b2e9 100644
--- a/include_core/omrgcconsts.h
+++ b/include_core/omrgcconsts.h
@@ -275,6 +275,14 @@ typedef enum {
 	COMPACT_MICRO_FRAG = 14
 } CompactReason;
 
+typedef enum {
+	RECONFIG_NONE = 0,
+	RECONFIG_EXPAND = 1,
+	RECONFIG_CONTRACT = 2,
+	RECONFIG_SCAVENGER_TILT = 3
+} HeapReconfigReason;
+
+
 typedef enum {
 	COMPACT_PREVENTED_NONE = 0,
 	COMPACT_PREVENTED_CRITICAL_REGIONS