Fix AllocationAge overflow issue

runtime/gc_vlhgc/ConfigurationIncrementalGenerational.cpp

@@ -304,6 +304,9 @@ MM_ConfigurationIncrementalGenerational::initialize(MM_EnvironmentBase *env)
 #define DEFAULT_MAX_NURSERY_AGE							1
 #define DEFAULT_MAX_AGE_FOR_ALLOCATION_BASED			5
 
+	/* enable AllocationAge by default for local testing */
+	extensions->tarokAllocationAgeEnabled = true;
+
 	/* set default region maximum age if it is not specified yet */
 	if (0 == extensions->tarokRegionMaxAge) {
 		if (extensions->tarokAllocationAgeEnabled) {

runtime/gc_vlhgc/CopyForwardScheme.cpp

@@ -1848,7 +1848,7 @@ MM_CopyForwardScheme::stopCopyingIntoCache(MM_EnvironmentVLHGC *env, uintptr_t c
 		MM_HeapRegionDescriptorVLHGC * region = (MM_HeapRegionDescriptorVLHGC *)_regionManager->tableDescriptorForAddress(copyCache->cacheBase);
 
 		/* atomically add (age * usedBytes) product from this cache to the regions product */
-		double newAllocationAgeSizeProduct = region->atomicIncrementAllocationAgeSizeProduct(copyCache->_allocationAgeSizeProduct);
+		double newAllocationAgeSizeProduct = region->atomicIncrementAllocationAgeSizeProduct(copyCache->_allocationAgeSizeProduct, copyCache->_objectSize);
 		region->updateAgeBounds(copyCache->_lowerAgeBound, copyCache->_upperAgeBound);
 
 		/* Return any remaining memory to the pool */
@@ -5638,7 +5638,7 @@ MM_CopyForwardScheme::setRegionAsSurvivor(MM_EnvironmentVLHGC *env, MM_HeapRegio
 	    (double)region->getAllocationAge() / (1024 * 1024), (double)usedBytes / (1024 * 1024), allocationAgeSizeProduct / (1024 * 1024) / (1024 * 1024));
 
 	Assert_MM_true(0.0 == region->getAllocationAgeSizeProduct());
-	region->setAllocationAgeSizeProduct(allocationAgeSizeProduct);
+	region->setAllocationAgeSizeProduct(allocationAgeSizeProduct, usedBytes);
 	if (freshSurvivor) {
 		region->resetAgeBounds();
 	}
@@ -5652,21 +5652,36 @@ MM_CopyForwardScheme::setRegionAsSurvivor(MM_EnvironmentVLHGC *env, MM_HeapRegio
 void
 MM_CopyForwardScheme::setAllocationAgeForMergedRegion(MM_EnvironmentVLHGC *env, MM_HeapRegionDescriptorVLHGC *region)
 {
-	uintptr_t compactGroup = MM_CompactGroupManager::getCompactGroupNumber(env, region);
-	uintptr_t usedBytes = region->getSize() - region->getMemoryPool()->getFreeMemoryAndDarkMatterBytes();
+	/* "Dark matter" refers to memory that appears allocated but isn't reachable.
+	 * This can cause inaccurate projections and potential Boundaries Overflow.
+	 * so use actual copied byte instead of calculating from getFreeMemoryAndDarkMatterBytes() for usedBytes.
+	 */
+//	uintptr_t usedBytes = region->getSize() - region->getMemoryPool()->getFreeMemoryAndDarkMatterBytes();
+	uintptr_t usedBytes = region->getUsedAllocationBytes();
 
 	Assert_MM_true(0 != usedBytes);
 
 	/* convert allocation age product (usedBytes * age) back to pure age */
 	uint64_t newAllocationAge = (uint64_t)(region->getAllocationAgeSizeProduct() / (double)usedBytes);
+	uintptr_t compactGroup = MM_CompactGroupManager::getCompactGroupNumber(env, region);
 
 	Trc_MM_CopyForwardScheme_setAllocationAgeForMergedRegion(env->getLanguageVMThread(), _regionManager->mapDescriptorToRegionTableIndex(region), compactGroup,
 	    region->getAllocationAgeSizeProduct() / (1024 * 1024) / (1024 * 1024), (double)usedBytes / (1024 * 1024), (double)newAllocationAge / (1024 * 1024),
 	    (double)region->getLowerAgeBound() / (1024 * 1024), (double)region->getUpperAgeBound() / (1024 * 1024));
 
 	if (_extensions->tarokAllocationAgeEnabled) {
 		Assert_MM_true(newAllocationAge < _extensions->compactGroupPersistentStats[compactGroup]._maxAllocationAge);
-		Assert_MM_true((MM_CompactGroupManager::getRegionAgeFromGroup(env, compactGroup) == 0) || (newAllocationAge >= _extensions->compactGroupPersistentStats[compactGroup - 1]._maxAllocationAge));
+
+		if ((MM_CompactGroupManager::getRegionAgeFromGroup(env, compactGroup) != 0) /*eden region */
+				&& (_extensions->compactGroupPersistentStats[compactGroup - 1]._maxAllocationAge != _extensions->tarokMaximumAgeInBytes) /* tenure region */
+				&& (newAllocationAge < _extensions->compactGroupPersistentStats[compactGroup - 1]._maxAllocationAge)) {
+		PORT_ACCESS_FROM_ENVIRONMENT(env);
+		j9tty_printf(PORTLIB, "setAllocationAgeForMergedRegion newAllocationAge=%zu, region->getLowerAgeBound()=%zu, _extensions->compactGroupPersistentStats[%zu]._maxAllocationAge=%zu, _extensions->compactGroupPersistentStats[%zu]._maxAllocationAge=%zu, _extensions->tarokMaximumAgeInBytes=%zu\n",
+					newAllocationAge, region->getLowerAgeBound(), compactGroup - 1, _extensions->compactGroupPersistentStats[compactGroup - 1]._maxAllocationAge, compactGroup, _extensions->compactGroupPersistentStats[compactGroup]._maxAllocationAge, _extensions->tarokMaximumAgeInBytes);
+		Assert_MM_true((MM_CompactGroupManager::getRegionAgeFromGroup(env, compactGroup) == 0) /*eden region */
+						|| _extensions->compactGroupPersistentStats[compactGroup - 1]._maxAllocationAge == _extensions->tarokMaximumAgeInBytes /* tenure region */
+						|| (newAllocationAge >= _extensions->compactGroupPersistentStats[compactGroup - 1]._maxAllocationAge));  /*survivior region */
+		}
 	}
 
 	uintptr_t logicalAge = 0;
@@ -5677,8 +5692,9 @@ MM_CopyForwardScheme::setAllocationAgeForMergedRegion(MM_EnvironmentVLHGC *env,
 	}
 
 	region->setAge(newAllocationAge, logicalAge);
-	/* reset aging auxiliary datea for future usage */
-	region->setAllocationAgeSizeProduct(0.0);
+
+	/* reset aging auxiliary data for future usage */
+	region->setAllocationAgeSizeProduct(0.0, 0);
 }
 
 bool

runtime/gc_vlhgc/HeapRegionDescriptorVLHGC.cpp

@@ -50,6 +50,7 @@ MM_HeapRegionDescriptorVLHGC::MM_HeapRegionDescriptorVLHGC(MM_EnvironmentVLHGC *
 	,_extensions(MM_GCExtensions::getExtensions(env))
 	,_allocationAge(0)
 	,_allocationAgeSizeProduct(0.0)
+	,_usedAllocationBytes(0)
 	,_age(0)
 	,_rememberedSetCardList()
 	,_rsclBufferPool(NULL)

runtime/gc_vlhgc/HeapRegionDescriptorVLHGC.hpp

@@ -94,6 +94,9 @@ class MM_HeapRegionDescriptorVLHGC : public MM_HeapRegionDescriptor
 	U_64 _lowerAgeBound; /**< lowest possible age of any object in this region */
 	U_64 _upperAgeBound; /**< highest possible age of any object in this region */
 	double _allocationAgeSizeProduct; /**< sum of (age * size) products for each object in the region. used for age merging math in survivor regions */
+
+	uintptr_t _usedAllocationBytes;
+
 	uintptr_t _age; /**< logical allocation age (number of GC cycles since the last attempted allocation) */
 	MM_RememberedSetCardList _rememberedSetCardList; /**< remembered set card list */
 	MM_RememberedSetCard *_rsclBufferPool;			 /**< RSCL Buffer pool owned by this region (Buffers can still be shared among other regions) */
@@ -128,23 +131,32 @@ class MM_HeapRegionDescriptorVLHGC : public MM_HeapRegionDescriptor
 		 return _allocationAgeSizeProduct;
 	}
 
+	MMINLINE uintptr_t getUsedAllocationBytes()
+	{
+		 return _usedAllocationBytes;
+	}
+
 	/**
-	 * set current value of (age * size) product used for survivor regions (used for setting its initial value)
+	 * Set current value of (age × size) product used for survivor regions
+	 * @param allocationAgeSizeProduct age to increment with
+	 * @param usedAllocationBytes actual bytes allocated (copied) in the region
 	 */
-	MMINLINE void setAllocationAgeSizeProduct(double allocationAgeSizeProduct)
+	MMINLINE void setAllocationAgeSizeProduct(double allocationAgeSizeProduct, uintptr_t usedAllocationBytes)
 	{
+		_usedAllocationBytes = usedAllocationBytes;
 		 _allocationAgeSizeProduct = allocationAgeSizeProduct;
 	}
 
-
 	/**
 	 * increment atomically allocation (age * size) product
 	 * @param allocationAgeSizeProduct age to increment with
+	 * @param copiedBytes
 	 * @return new allocationAgeSizeProduct value
 	 */
-	MMINLINE double atomicIncrementAllocationAgeSizeProduct(double allocationAgeSizeProduct)
+	MMINLINE double atomicIncrementAllocationAgeSizeProduct(double allocationAgeSizeProduct, uintptr_t copiedBytes)
 	{
-		 return MM_AtomicOperations::addDouble(&_allocationAgeSizeProduct, allocationAgeSizeProduct);
+		MM_AtomicOperations::add(&_usedAllocationBytes, copiedBytes);
+		return MM_AtomicOperations::addDouble(&_allocationAgeSizeProduct, allocationAgeSizeProduct);
 	}
 
 	/**