/**
* Walk all segments and calculate the maximum number of chunks needed to represent the current heap.
* The chunk calculation is done on a per segment basis (no segment can represent memory from more than 1 chunk),
* and partial sized chunks (ie: less than the chunk size) are reserved for any remaining space at the end of a
* segment.
* @return number of chunks required to represent the current heap memory.
*/
uintptr_t
MM_SweepHeapSectioningSegmented::calculateActualChunkNumbers() const
{
uintptr_t totalChunkCount = 0;
MM_HeapRegionDescriptor *region;
MM_Heap *heap = _extensions->heap;
MM_HeapRegionManager *regionManager = heap->getHeapRegionManager();
GC_HeapRegionIterator regionIterator(regionManager);
while((region = regionIterator.nextRegion()) != NULL) {
if ((region)->isCommitted()) {
/* TODO: this must be rethought for Tarok since it treats all regions identically but some might require different sweep logic */
MM_MemorySubSpace *subspace = region->getSubSpace();
/* if this is a committed region, it requires a non-NULL subspace */
Assert_MM_true(NULL != subspace);
uintptr_t poolCount = subspace->getMemoryPoolCount();
totalChunkCount += MM_Math::roundToCeiling(_extensions->parSweepChunkSize, region->getSize()) / _extensions->parSweepChunkSize;
/* Add extra chunks if more than one memory pool */
totalChunkCount += (poolCount - 1);
}
}
return totalChunkCount;
}
/**
* Reset and reassign each chunk to a range of heap memory.
* Given the current updated listed of chunks and the corresponding heap memory, walk the chunk
* list reassigning each chunk to an appropriate range of memory. This will clear each chunk
* structure and then assign its basic values that connect it to a range of memory (base/top,
* pool, segment, etc).
* @return the total number of chunks in the system.
*/
uintptr_t
MM_SweepHeapSectioningSegmented::reassignChunks(MM_EnvironmentBase *env)
{
MM_ParallelSweepChunk *chunk; /* Sweep table chunk (global) */
MM_ParallelSweepChunk *previousChunk;
uintptr_t totalChunkCount; /* Total chunks in system */
MM_SweepHeapSectioningIterator sectioningIterator(this);
totalChunkCount = 0;
previousChunk = NULL;
MM_HeapRegionManager *regionManager = _extensions->getHeap()->getHeapRegionManager();
GC_HeapRegionIterator regionIterator(regionManager);
MM_HeapRegionDescriptor *region = NULL;
while (NULL != (region = regionIterator.nextRegion())) {
if (region->isCommitted()) {
/* TODO: this must be rethought for Tarok since it treats all regions identically but some might require different sweep logic */
uintptr_t *heapChunkBase = (uintptr_t *)region->getLowAddress(); /* Heap chunk base pointer */
uintptr_t *regionHighAddress = (uintptr_t *)region->getHighAddress();
while (heapChunkBase < regionHighAddress) {
void *poolHighAddr;
uintptr_t *heapChunkTop;
MM_MemoryPool *pool;
chunk = sectioningIterator.nextChunk();
Assert_MM_true(chunk != NULL); /* Should never return NULL */
totalChunkCount += 1;
/* Clear all data in the chunk (including sweep implementation specific information) */
chunk->clear();
if(((uintptr_t)regionHighAddress - (uintptr_t)heapChunkBase) < _extensions->parSweepChunkSize) {
/* corner case - we will wrap our address range */
heapChunkTop = regionHighAddress;
} else {
/* normal case - just increment by the chunk size */
heapChunkTop = (uintptr_t *)((uintptr_t)heapChunkBase + _extensions->parSweepChunkSize);
}
/* Find out if the range of memory we are considering spans 2 different pools. If it does,
* the current chunk can only be attributed to one, so we limit the upper range of the chunk
* to the first pool and will continue the assignment at the upper address range.
*/
pool = region->getSubSpace()->getMemoryPool(env, heapChunkBase, heapChunkTop, poolHighAddr);
if (NULL == poolHighAddr) {
heapChunkTop = (heapChunkTop > regionHighAddress ? regionHighAddress : heapChunkTop);
} else {
/* Yes ..so adjust chunk boundaries */
assume0(poolHighAddr > heapChunkBase && poolHighAddr < heapChunkTop);
heapChunkTop = (uintptr_t *) poolHighAddr;
}
/* All values for the chunk have been calculated - assign them */
chunk->chunkBase = (void *)heapChunkBase;
chunk->chunkTop = (void *)heapChunkTop;
chunk->memoryPool = pool;
chunk->_coalesceCandidate = (heapChunkBase != region->getLowAddress());
chunk->_previous= previousChunk;
if(NULL != previousChunk) {
previousChunk->_next = chunk;
}
/* Move to the next chunk */
heapChunkBase = heapChunkTop;
/* and remember address of previous chunk */
previousChunk = chunk;
assume0((uintptr_t)heapChunkBase == MM_Math::roundToCeiling(_extensions->heapAlignment,(uintptr_t)heapChunkBase));
}
}
}
if(NULL != previousChunk) {
previousChunk->_next = NULL;
}
return totalChunkCount;
}