void
MM_OverflowStandard::handleOverflow(MM_EnvironmentBase *env)
{
if (env->_currentTask->synchronizeGCThreadsAndReleaseMaster(env, UNIQUE_ID)) {
_overflow = false;
MM_Heap *heap = _extensions->heap;
MM_HeapRegionManager *regionManager = heap->getHeapRegionManager();
GC_HeapRegionIterator regionIterator(regionManager);
MM_HeapRegionDescriptor *region = NULL;
// MM_ParallelGlobalGC *globalCollector = (MM_ParallelGlobalGC *)_extensions->getGlobalCollector();
MM_MarkMap *markMap = env->getMarkingEnvironment()->markingExtensions()->markMap();
while((region = regionIterator.nextRegion()) != NULL) {
GC_ObjectHeapIteratorAddressOrderedList objectIterator(_extensions, region, false);
omrobjectptr_t object;
while((object = objectIterator.nextObject()) != NULL) {
/* search for double marked (overflowed) objects */
if ((markMap->isBitSet(object)) && (markMap->isBitSet((omrobjectptr_t)((uintptr_t)object + markMap->getObjectGrain())))) {
/* clean overflow mark */
markMap->clearBit((omrobjectptr_t)((uintptr_t)object + markMap->getObjectGrain()));
/* scan overflowed object */
OMR::App::ObjectScanner().scanObject(env, env->getMarkingEnvironment(), object, SCAN_REASON_OVERFLOWED_OBJECT);
}
}
}
env->_currentTask->releaseSynchronizedGCThreads(env);
}
}
/**
* 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;
}
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;
}
}
}
}
void
MM_ConcurrentOverflow::handleOverflow(MM_EnvironmentBase *env)
{
MM_EnvironmentStandard *envStandard = MM_EnvironmentStandard::getEnvironment(env);
if (envStandard->_currentTask->synchronizeGCThreadsAndReleaseMaster(env, UNIQUE_ID)) {
_overflow = false;
envStandard->_currentTask->releaseSynchronizedGCThreads(envStandard);
}
MM_Heap *heap = _extensions->heap;
MM_HeapRegionManager *regionManager = heap->getHeapRegionManager();
GC_HeapRegionIterator regionIterator(regionManager);
MM_HeapRegionDescriptor *region = NULL;
MM_ConcurrentGC *collector = (MM_ConcurrentGC *)_extensions->getGlobalCollector();
MM_CardCleanerForMarking cardCleanerForMarking(collector->getMarkingScheme());
MM_ConcurrentCardTable *cardTable = collector->getCardTable();
while((region = regionIterator.nextRegion()) != NULL) {
cardTable->cleanCardTableForRange(envStandard, &cardCleanerForMarking, region->getLowAddress(), region->getHighAddress());
}
envStandard->_currentTask->synchronizeGCThreads(env, UNIQUE_ID);
}
/* a helper to get the root region manager from the heap, since it was needed in so many place */
MM_HeapRegionManager *getHeapRegionManager() {return _heap->getHeapRegionManager();}