void
MM_MarkMap::initializeMarkMap(MM_EnvironmentBase *env)
{
/* TODO: The multiplier should really be some constant defined globally */
const uintptr_t MODRON_PARALLEL_MULTIPLIER = 32;
uintptr_t heapAlignment = _extensions->heapAlignment;
/* Determine the size of heap that a work unit of mark map clearing corresponds to */
uintptr_t heapClearUnitFactor = env->_currentTask->getThreadCount();
heapClearUnitFactor = ((heapClearUnitFactor == 1) ? 1 : heapClearUnitFactor * MODRON_PARALLEL_MULTIPLIER);
uintptr_t heapClearUnitSize = _extensions->heap->getMemorySize() / heapClearUnitFactor;
heapClearUnitSize = MM_Math::roundToCeiling(heapAlignment, heapClearUnitSize);
/* Walk all object segments to determine what ranges of the mark map should be cleared */
MM_HeapRegionDescriptor *region;
MM_Heap *heap = _extensions->getHeap();
MM_HeapRegionManager *regionManager = heap->getHeapRegionManager();
GC_HeapRegionIterator regionIterator(regionManager);
while(NULL != (region = regionIterator.nextRegion())) {
if (region->isCommitted()) {
/* Walk the segment in chunks the size of the heapClearUnit size, checking if the corresponding mark map
* range should be cleared.
*/
uint8_t* heapClearAddress = (uint8_t*)region->getLowAddress();
uintptr_t heapClearSizeRemaining = region->getSize();
while(0 != heapClearSizeRemaining) {
/* Calculate the size of heap that is to be processed */
uintptr_t heapCurrentClearSize = (heapClearUnitSize > heapClearSizeRemaining) ? heapClearSizeRemaining : heapClearUnitSize;
Assert_MM_true(heapCurrentClearSize > 0);
/* Check if the thread should clear the corresponding mark map range for the current heap range */
if(J9MODRON_HANDLE_NEXT_WORK_UNIT(env)) {
/* Convert the heap address/size to its corresponding mark map address/size */
/* NOTE: We calculate the low and high heap offsets, and build the mark map index and size values
* from these to avoid rounding errors (if we use the size, the conversion routine could get a different
* rounding result then the actual end address)
*/
uintptr_t heapClearOffset = ((uintptr_t)heapClearAddress) - _heapMapBaseDelta;
uintptr_t heapMapClearIndex = convertHeapIndexToHeapMapIndex(env, heapClearOffset, sizeof(uintptr_t));
uintptr_t heapMapClearSize =
convertHeapIndexToHeapMapIndex(env, heapClearOffset + heapCurrentClearSize, sizeof(uintptr_t))
- heapMapClearIndex;
/* And clear the mark map */
OMRZeroMemory((void *) (((uintptr_t)_heapMapBits) + heapMapClearIndex), heapMapClearSize);
}
/* Move to the next address range in the segment */
heapClearAddress += heapCurrentClearSize;
heapClearSizeRemaining -= heapCurrentClearSize;
}
}
}
}
/**
* 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;
}