C++ MM_GCExtensionsBase::isDebugConcurrentScavengerPageAlignment方法代码示例

bool
MM_MemoryManager::createVirtualMemoryForHeap(MM_EnvironmentBase* env, MM_MemoryHandle* handle, uintptr_t heapAlignment, uintptr_t size, uintptr_t tailPadding, void* preferredAddress, void* ceiling)
{
	Assert_MM_true(NULL != handle);
	MM_GCExtensionsBase* extensions = env->getExtensions();

	MM_VirtualMemory* instance = NULL;
	uintptr_t mode = (OMRPORT_VMEM_MEMORY_MODE_READ | OMRPORT_VMEM_MEMORY_MODE_WRITE);
	uintptr_t options = 0;
	uint32_t memoryCategory = OMRMEM_CATEGORY_MM_RUNTIME_HEAP;

	uintptr_t pageSize = extensions->requestedPageSize;
	uintptr_t pageFlags = extensions->requestedPageFlags;
	Assert_MM_true(0 != pageSize);

	uintptr_t allocateSize = size;

	uintptr_t concurrentScavengerPageSize = 0;
	if (extensions->isConcurrentScavengerEnabled()) {
		OMRPORT_ACCESS_FROM_ENVIRONMENT(env);
		/*
		 * Allocate extra memory to guarantee proper alignment regardless start address location
		 * Minimum size of over-allocation should be (Concurrent_Scavenger_page_size - section size) however
		 * Virtual Memory can return heap size shorter by a region (and here region size == section size)
		 * So to guarantee desired heap size over-allocate it by full Concurrent_Scavenger_page_size
		 */
		concurrentScavengerPageSize = extensions->getConcurrentScavengerPageSectionSize() * CONCURRENT_SCAVENGER_PAGE_SECTIONS;
		allocateSize += concurrentScavengerPageSize;
		if (extensions->isDebugConcurrentScavengerPageAlignment()) {
			omrtty_printf("Requested heap size 0x%zx has been extended to 0x%zx for guaranteed alignment\n", size, allocateSize);
		}
	} else {
		if (heapAlignment > pageSize) {
			allocateSize += (heapAlignment - pageSize);
		}
	}

#if defined(OMR_GC_MODRON_SCAVENGER)
	if (extensions->enableSplitHeap) {
		/* currently (ceiling != NULL) is using to recognize CompressedRefs so must be NULL for 32 bit platforms */
		Assert_MM_true(NULL == ceiling);

		switch(extensions->splitHeapSection) {
		case MM_GCExtensionsBase::HEAP_INITIALIZATION_SPLIT_HEAP_TENURE:
			/* trying to get Tenure at the bottom of virtual memory */
			options |= OMRPORT_VMEM_ALLOC_DIR_BOTTOM_UP;
			break;
		case MM_GCExtensionsBase::HEAP_INITIALIZATION_SPLIT_HEAP_NURSERY:
			/* trying to get Nursery at the top of virtual memory */
			options |= OMRPORT_VMEM_ALLOC_DIR_TOP_DOWN;
			break;
		case MM_GCExtensionsBase::HEAP_INITIALIZATION_SPLIT_HEAP_UNKNOWN:
		default:
			Assert_MM_unreachable();
			break;
		}
	}
#endif /* defined(OMR_GC_MODRON_SCAVENGER) */

	if (NULL == ceiling) {
		instance = MM_VirtualMemory::newInstance(env, heapAlignment, allocateSize, pageSize, pageFlags, tailPadding, preferredAddress,
												 ceiling, mode, options, memoryCategory);
	} else {
#if defined(OMR_GC_COMPRESSED_POINTERS)
		OMRPORT_ACCESS_FROM_ENVIRONMENT(env);
		/*
		 * This function is used for Compressed References platforms only
		 * The ceiling for such platforms is set maximum memory value be supported (32G for 3-bit shift)
		 * The ceiling it is 0 for all other platforms
		 */
		/* NON_SCALING_LOW_MEMORY_HEAP_CEILING is set to 4G for 64-bit platforms only, 0 for 32-bit platforms */
		Assert_MM_true(NON_SCALING_LOW_MEMORY_HEAP_CEILING > 0);
		
		/*
		 * Usually the suballocator memory should be allocated first (before heap) however
		 * in case when preferred address is specified we will try to allocate heap first
		 * to avoid possible interference with requested heap location
		 */
		bool shouldHeapBeAllocatedFirst = (NULL != preferredAddress);
		void* startAllocationAddress = preferredAddress;

		/* Set the commit size for the sub allocator. This needs to be completed before the call to omrmem_ensure_capacity32 */
		omrport_control(OMRPORT_CTLDATA_ALLOCATE32_COMMIT_SIZE, extensions->suballocatorCommitSize);

		if (!shouldHeapBeAllocatedFirst) {
			if (OMRPORT_ENSURE_CAPACITY_FAILED == omrmem_ensure_capacity32(extensions->suballocatorInitialSize)) {
				extensions->heapInitializationFailureReason = MM_GCExtensionsBase::HEAP_INITIALIZATION_FAILURE_REASON_CAN_NOT_ALLOCATE_LOW_MEMORY_RESERVE;
				return false;
			}
		}

		options |= OMRPORT_VMEM_STRICT_ADDRESS | OMRPORT_VMEM_ALLOC_QUICK;

#if defined(J9ZOS39064)
		/* 2TO32G area is extended to 64G */
		options |= OMRPORT_VMEM_ZOS_USE2TO32G_AREA;

		/*
		 * On ZOS an address space below 2G can not be taken for virtual memory
		 */
//.........这里部分代码省略.........