/**
* Attach a physical arena of the specified size to the receiver.
* This reserves the address space within the receiver for the arena, and connects the arena to the list
* of those associated to the receiver (in address order).
*
* @return true if the arena was attached successfully, false otherwise.
* @note The memory reseved is not commited.
*/
bool
MM_HeapVirtualMemory::attachArena(MM_EnvironmentBase* env, MM_PhysicalArena* arena, uintptr_t size)
{
/* Sanity check of the size */
if (getMaximumMemorySize() < size) {
return false;
}
MM_GCExtensionsBase* extensions = env->getExtensions();
MM_MemoryManager* memoryManager = extensions->memoryManager;
/* Find the insertion point for the currentArena */
void* candidateBase = memoryManager->getHeapBase(&_vmemHandle);
MM_PhysicalArena* insertionHead = NULL;
MM_PhysicalArena* insertionTail = _physicalArena;
MM_PhysicalArena* currentArena = arena;
while (insertionTail) {
if ((((uintptr_t)insertionTail->getLowAddress()) - ((uintptr_t)candidateBase)) >= size) {
break;
}
candidateBase = insertionTail->getHighAddress();
insertionHead = insertionTail;
insertionTail = insertionTail->getNextArena();
}
/* If we have reached the end of the currentArena list, check if there is room between the candidateBase
* and the end of virtual memory */
if (!insertionTail) {
if ((memoryManager->calculateOffsetToHeapTop(&_vmemHandle, candidateBase)) < size) {
return false;
}
}
/* Connect the physical currentArena into the list at the appropriate point */
currentArena->setPreviousArena(insertionHead);
currentArena->setNextArena(insertionTail);
if (insertionTail) {
insertionTail->setPreviousArena(currentArena);
}
if (insertionHead) {
insertionHead->setNextArena(currentArena);
} else {
_physicalArena = currentArena;
}
currentArena->setLowAddress(candidateBase);
currentArena->setHighAddress((void*)(((uint8_t*)candidateBase) + size));
/* Set the arena state to being attached */
arena->setAttached(true);
return true;
}
