initializeGCParameters For CRIU Restore

Relates to
eclipse-openj9/openj9#17459 (comment)

Signed-off-by: Salman Rana <salman.rana@ibm.com>

gc/base/Configuration.cpp

@@ -89,7 +89,7 @@ MM_Configuration::tearDown(MM_EnvironmentBase* env)
 	/* DefaultMemorySpace needs to be killed before
 	 * ext->heap is freed in MM_Configuration::tearDown. */
 	if (NULL != extensions->heap) {
-		MM_MemorySpace *modronMemorySpace = extensions->heap->getDefaultMemorySpace();
+		MM_MemorySpace* modronMemorySpace = extensions->heap->getDefaultMemorySpace();
 		if  (NULL != modronMemorySpace) {
 			modronMemorySpace->kill(env);
 		}
@@ -153,7 +153,7 @@ void
 MM_Configuration::destroyCollectors(MM_EnvironmentBase* env)
 {
 	MM_GCExtensionsBase* extensions = env->getExtensions();
-	MM_Collector *collector = extensions->getGlobalCollector();
+	MM_Collector* collector = extensions->getGlobalCollector();
 
 	if (NULL != collector) {
 		collector->kill(env);
@@ -279,7 +279,7 @@ bool
 MM_Configuration::initializeRunTimeObjectAlignmentAndCRShift(MM_EnvironmentBase* env, MM_Heap* heap)
 {
 	MM_GCExtensionsBase* extensions = env->getExtensions();
-	OMR_VM *omrVM = env->getOmrVM();
+	OMR_VM* omrVM = env->getOmrVM();
 
 #if defined(OMR_GC_COMPRESSED_POINTERS)
 	if (env->compressObjectReferences()) {
@@ -521,7 +521,31 @@ MM_Configuration::initializeNUMAManager(MM_EnvironmentBase* env)
 }
 
 MM_ParallelDispatcher *
-MM_Configuration::createParallelDispatcher(MM_EnvironmentBase *env, omrsig_handler_fn handler, void* handler_arg, uintptr_t defaultOSStackSize)
+MM_Configuration::createParallelDispatcher(MM_EnvironmentBase* env, omrsig_handler_fn handler, void* handler_arg, uintptr_t defaultOSStackSize)
 {
 	return MM_ParallelDispatcher::newInstance(env, handler, handler_arg, defaultOSStackSize);
 }
+
+#if defined(J9VM_OPT_CRIU_SUPPORT)
+bool
+MM_Configuration::reinitializeForRestore(MM_EnvironmentBase* env)
+{
+	MM_GCExtensionsBase* extensions = env->getExtensions();
+
+	/* The initialization of the GC thread count can only happen if it is not enforced by the user. */
+	initializeGCThreadCount(env);
+
+	/* Currently, threads don't shutdown during reinitialization, so it is important to
+	 * prevent the thread count from dropping below the number of checkpoint threads.
+	 * This adjustment may no longer be necessary in the future once the shutdown behavior
+	 * of dispatcher threads during restore is thoroughly tested.
+	 */
+	extensions->gcThreadCount = OMR_MAX(
+			extensions->dispatcher->threadCountMaximum(),
+			extensions->gcThreadCount);
+
+	initializeGCParameters(env);
+
+	return true;
+}
+#endif /* defined(J9VM_OPT_CRIU_SUPPORT) */

gc/base/Configuration.hpp

@@ -109,10 +109,10 @@ class MM_Configuration : public MM_BaseVirtual
 	virtual MM_MemorySpace* createDefaultMemorySpace(MM_EnvironmentBase* env, MM_Heap* heap, MM_InitializationParameters* parameters) = 0;
 	MM_EnvironmentBase* createEnvironment(MM_GCExtensionsBase* extensions, OMR_VMThread* vmThread);
 	virtual J9Pool* createEnvironmentPool(MM_EnvironmentBase* env) = 0;
-	virtual MM_ParallelDispatcher* createParallelDispatcher(MM_EnvironmentBase *env, omrsig_handler_fn handler, void* handler_arg, uintptr_t defaultOSStackSize);
+	virtual MM_ParallelDispatcher* createParallelDispatcher(MM_EnvironmentBase* env, omrsig_handler_fn handler, void* handler_arg, uintptr_t defaultOSStackSize);
 
-	bool initializeHeapRegionDescriptor(MM_EnvironmentBase *env, MM_HeapRegionDescriptor *region) { return _delegate.initializeHeapRegionDescriptorExtension(env, region); }
-	void teardownHeapRegionDescriptor(MM_EnvironmentBase *env, MM_HeapRegionDescriptor *region) { _delegate.teardownHeapRegionDescriptorExtension(env, region); }
+	bool initializeHeapRegionDescriptor(MM_EnvironmentBase* env, MM_HeapRegionDescriptor* region) { return _delegate.initializeHeapRegionDescriptorExtension(env, region); }
+	void teardownHeapRegionDescriptor(MM_EnvironmentBase* env, MM_HeapRegionDescriptor* region) { _delegate.teardownHeapRegionDescriptorExtension(env, region); }
 
 	MMINLINE MM_GCWriteBarrierType getBarrierType() { return _writeBarrierType; }
 
@@ -134,7 +134,7 @@ class MM_Configuration : public MM_BaseVirtual
 	 * Delegated method to determine when to start tracking heap fragmentation, which should be inhibited
 	 * until the heap has grown to a stable operational size.
 	 */
-	MMINLINE bool canCollectFragmentationStats(MM_EnvironmentBase *env) { return _delegate.canCollectFragmentationStats(env); }
+	MMINLINE bool canCollectFragmentationStats(MM_EnvironmentBase* env) { return _delegate.canCollectFragmentationStats(env); }
 
 	/**
 	 * Called once during startup to indicate that the default memory space has been allocated.
@@ -178,11 +178,7 @@ class MM_Configuration : public MM_BaseVirtual
 	 * @param[in] env the current environment.
 	 * @return boolean indicating whether the configuration was successfully updated.
 	 */
-	virtual bool reinitializeForRestore(MM_EnvironmentBase* env)
-	{
-		Assert_MM_unreachable();
-		return false;
-	}
+	virtual bool reinitializeForRestore(MM_EnvironmentBase* env);
 #endif /* defined(J9VM_OPT_CRIU_SUPPORT) */
 
 	MM_Configuration(MM_EnvironmentBase* env, MM_GCPolicy gcPolicy, MM_AlignmentType alignmentType, uintptr_t defaultRegionSize, uintptr_t defaultArrayletLeafSize, MM_GCWriteBarrierType writeBarrierType, MM_GCAllocationType allocationType)

gc/base/standard/ConfigurationStandard.cpp

@@ -107,7 +107,7 @@ MM_GlobalCollector*
 MM_ConfigurationStandard::createCollectors(MM_EnvironmentBase* env)
 {
 #if defined(OMR_GC_MODRON_CONCURRENT_MARK) || defined(OMR_GC_MODRON_CONCCURENT_SWEEP)
-	MM_GCExtensionsBase *extensions = env->getExtensions();
+	MM_GCExtensionsBase* extensions = env->getExtensions();
 #endif /* OMR_GC_MODRON_CONCURRENT_MARK || OMR_GC_CONCURRENT_SWEEP */
 
 #if defined(OMR_GC_MODRON_CONCURRENT_MARK)
@@ -340,7 +340,9 @@ MM_ConfigurationStandard::reinitializeForRestore(MM_EnvironmentBase* env)
 {
 	MM_GCExtensionsBase* extensions = env->getExtensions();
 
-	MM_MemoryPool *memoryPool;
+	MM_Configuration::reinitializeForRestore(env);
+
+	MM_MemoryPool* memoryPool;
 	MM_HeapMemoryPoolIterator poolIterator(env, extensions->heap);
 
 	while (NULL != (memoryPool = poolIterator.nextPool())) {