Heap::Heap(VM* vm, HeapType heapType)
: m_heapType(heapType)
, m_ramSize(ramSize())
, m_minBytesPerCycle(minHeapSize(m_heapType, m_ramSize))
, m_sizeAfterLastCollect(0)
, m_bytesAllocatedLimit(m_minBytesPerCycle)
, m_bytesAllocated(0)
, m_bytesAbandoned(0)
, m_totalBytesVisited(0)
, m_totalBytesCopied(0)
, m_operationInProgress(NoOperation)
, m_blockAllocator()
, m_objectSpace(this)
, m_storageSpace(this)
, m_extraMemoryUsage(0)
, m_machineThreads(this)
, m_sharedData(vm)
, m_slotVisitor(m_sharedData)
, m_copyVisitor(m_sharedData)
, m_handleSet(vm)
, m_isSafeToCollect(false)
, m_vm(vm)
, m_lastGCLength(0)
, m_lastCodeDiscardTime(WTF::monotonicallyIncreasingTime())
, m_activityCallback(DefaultGCActivityCallback::create(this))
, m_sweeper(IncrementalSweeper::create(this))
, m_deferralDepth(0)
{
m_storageSpace.init();
}
Heap::Heap(JSGlobalData* globalData, HeapType heapType)
: m_heapType(heapType)
, m_ramSize(ramSize())
, m_minBytesPerCycle(minHeapSize(m_heapType, m_ramSize))
, m_sizeAfterLastCollect(0)
, m_bytesAllocatedLimit(m_minBytesPerCycle)
, m_bytesAllocated(0)
, m_bytesAbandoned(0)
, m_operationInProgress(NoOperation)
, m_blockAllocator()
, m_objectSpace(this)
, m_storageSpace(this)
, m_machineThreads(this)
, m_sharedData(globalData)
, m_slotVisitor(m_sharedData)
, m_copyVisitor(m_sharedData)
, m_handleSet(globalData)
, m_isSafeToCollect(false)
, m_globalData(globalData)
, m_lastGCLength(0)
, m_lastCodeDiscardTime(WTF::currentTime())
, m_activityCallback(DefaultGCActivityCallback::create(this))
, m_sweeper(IncrementalSweeper::create(this))
{
m_storageSpace.init();
}
Heap::Heap(VM* vm, HeapType heapType)
: m_heapType(heapType)
, m_ramSize(Options::forceRAMSize() ? Options::forceRAMSize() : ramSize())
, m_minBytesPerCycle(minHeapSize(m_heapType, m_ramSize))
, m_sizeAfterLastCollect(0)
, m_sizeAfterLastFullCollect(0)
, m_sizeBeforeLastFullCollect(0)
, m_sizeAfterLastEdenCollect(0)
, m_sizeBeforeLastEdenCollect(0)
, m_bytesAllocatedThisCycle(0)
, m_bytesAbandonedSinceLastFullCollect(0)
, m_maxEdenSize(m_minBytesPerCycle)
, m_maxHeapSize(m_minBytesPerCycle)
, m_shouldDoFullCollection(false)
, m_totalBytesVisited(0)
, m_totalBytesCopied(0)
, m_operationInProgress(NoOperation)
, m_objectSpace(this)
, m_storageSpace(this)
, m_extraMemorySize(0)
, m_deprecatedExtraMemorySize(0)
, m_machineThreads(this)
, m_sharedData(vm)
, m_slotVisitor(m_sharedData)
, m_copyVisitor(m_sharedData)
, m_handleSet(vm)
, m_isSafeToCollect(false)
, m_writeBarrierBuffer(256)
, m_vm(vm)
// We seed with 10ms so that GCActivityCallback::didAllocate doesn't continuously
// schedule the timer if we've never done a collection.
, m_lastFullGCLength(0.01)
, m_lastEdenGCLength(0.01)
, m_fullActivityCallback(GCActivityCallback::createFullTimer(this))
#if ENABLE(GGC)
, m_edenActivityCallback(GCActivityCallback::createEdenTimer(this))
#else
, m_edenActivityCallback(m_fullActivityCallback)
#endif
#if USE(CF)
, m_sweeper(std::make_unique<IncrementalSweeper>(this, CFRunLoopGetCurrent()))
#else
, m_sweeper(std::make_unique<IncrementalSweeper>(this->vm()))
#endif
, m_deferralDepth(0)
#if USE(CF)
, m_delayedReleaseRecursionCount(0)
#endif
{
m_storageSpace.init();
if (Options::verifyHeap())
m_verifier = std::make_unique<HeapVerifier>(this, Options::numberOfGCCyclesToRecordForVerification());
}
void Heap::updateAllocationLimits()
{
GCPHASE(UpdateAllocationLimits);
size_t currentHeapSize = sizeAfterCollect();
if (Options::gcMaxHeapSize() && currentHeapSize > Options::gcMaxHeapSize())
HeapStatistics::exitWithFailure();
if (m_operationInProgress == FullCollection) {
// To avoid pathological GC churn in very small and very large heaps, we set
// the new allocation limit based on the current size of the heap, with a
// fixed minimum.
m_maxHeapSize = max(minHeapSize(m_heapType, m_ramSize), proportionalHeapSize(currentHeapSize, m_ramSize));
m_maxEdenSize = m_maxHeapSize - currentHeapSize;
m_sizeAfterLastFullCollect = currentHeapSize;
m_bytesAbandonedSinceLastFullCollect = 0;
} else {
ASSERT(currentHeapSize >= m_sizeAfterLastCollect);
m_maxEdenSize = m_maxHeapSize - currentHeapSize;
m_sizeAfterLastEdenCollect = currentHeapSize;
double edenToOldGenerationRatio = (double)m_maxEdenSize / (double)m_maxHeapSize;
double minEdenToOldGenerationRatio = 1.0 / 3.0;
if (edenToOldGenerationRatio < minEdenToOldGenerationRatio)
m_shouldDoFullCollection = true;
m_maxHeapSize += currentHeapSize - m_sizeAfterLastCollect;
m_maxEdenSize = m_maxHeapSize - currentHeapSize;
if (m_fullActivityCallback) {
ASSERT(currentHeapSize >= m_sizeAfterLastFullCollect);
m_fullActivityCallback->didAllocate(currentHeapSize - m_sizeAfterLastFullCollect);
}
}
m_sizeAfterLastCollect = currentHeapSize;
m_bytesAllocatedThisCycle = 0;
if (Options::logGC())
dataLog(currentHeapSize / 1024, " kb, ");
}
void Heap::collect(SweepToggle sweepToggle)
{
#if ENABLE(ALLOCATION_LOGGING)
dataLogF("JSC GC starting collection.\n");
#endif
double before = 0;
if (Options::logGC()) {
dataLog("[GC", sweepToggle == DoSweep ? " (eager sweep)" : "", ": ");
before = currentTimeMS();
}
SamplingRegion samplingRegion("Garbage Collection");
RELEASE_ASSERT(!m_deferralDepth);
GCPHASE(Collect);
ASSERT(vm()->currentThreadIsHoldingAPILock());
RELEASE_ASSERT(vm()->identifierTable == wtfThreadData().currentIdentifierTable());
ASSERT(m_isSafeToCollect);
JAVASCRIPTCORE_GC_BEGIN();
RELEASE_ASSERT(m_operationInProgress == NoOperation);
m_deferralDepth++; // Make sure that we don't GC in this call.
m_vm->prepareToDiscardCode();
m_deferralDepth--; // Decrement deferal manually, so we don't GC when we do so, since we are already GCing!.
m_operationInProgress = Collection;
m_extraMemoryUsage = 0;
if (m_activityCallback)
m_activityCallback->willCollect();
double lastGCStartTime = WTF::monotonicallyIncreasingTime();
if (lastGCStartTime - m_lastCodeDiscardTime > minute) {
deleteAllCompiledCode();
m_lastCodeDiscardTime = WTF::monotonicallyIncreasingTime();
}
{
GCPHASE(StopAllocation);
m_objectSpace.stopAllocating();
}
markRoots();
{
GCPHASE(ReapingWeakHandles);
m_objectSpace.reapWeakSets();
}
JAVASCRIPTCORE_GC_MARKED();
{
GCPHASE(SweepingArrayBuffers);
m_arrayBuffers.sweep();
}
{
m_blockSnapshot.resize(m_objectSpace.blocks().set().size());
MarkedBlockSnapshotFunctor functor(m_blockSnapshot);
m_objectSpace.forEachBlock(functor);
}
copyBackingStores();
{
GCPHASE(FinalizeUnconditionalFinalizers);
finalizeUnconditionalFinalizers();
}
{
GCPHASE(DeleteCodeBlocks);
deleteUnmarkedCompiledCode();
}
{
GCPHASE(DeleteSourceProviderCaches);
m_vm->clearSourceProviderCaches();
}
if (sweepToggle == DoSweep) {
SamplingRegion samplingRegion("Garbage Collection: Sweeping");
GCPHASE(Sweeping);
m_objectSpace.sweep();
m_objectSpace.shrink();
}
m_sweeper->startSweeping(m_blockSnapshot);
m_bytesAbandoned = 0;
{
GCPHASE(ResetAllocators);
m_objectSpace.resetAllocators();
}
size_t currentHeapSize = sizeAfterCollect();
if (Options::gcMaxHeapSize() && currentHeapSize > Options::gcMaxHeapSize())
HeapStatistics::exitWithFailure();
m_sizeAfterLastCollect = currentHeapSize;
// To avoid pathological GC churn in very small and very large heaps, we set
// the new allocation limit based on the current size of the heap, with a
// fixed minimum.
size_t maxHeapSize = max(minHeapSize(m_heapType, m_ramSize), proportionalHeapSize(currentHeapSize, m_ramSize));
m_bytesAllocatedLimit = maxHeapSize - currentHeapSize;
m_bytesAllocated = 0;
double lastGCEndTime = WTF::monotonicallyIncreasingTime();
m_lastGCLength = lastGCEndTime - lastGCStartTime;
if (Options::recordGCPauseTimes())
HeapStatistics::recordGCPauseTime(lastGCStartTime, lastGCEndTime);
RELEASE_ASSERT(m_operationInProgress == Collection);
m_operationInProgress = NoOperation;
JAVASCRIPTCORE_GC_END();
if (Options::useZombieMode())
zombifyDeadObjects();
if (Options::objectsAreImmortal())
markDeadObjects();
if (Options::showObjectStatistics())
HeapStatistics::showObjectStatistics(this);
if (Options::logGC()) {
double after = currentTimeMS();
dataLog(after - before, " ms, ", currentHeapSize / 1024, " kb]\n");
}
#if ENABLE(ALLOCATION_LOGGING)
dataLogF("JSC GC finishing collection.\n");
#endif
}
void Heap::collect(SweepToggle sweepToggle)
{
SamplingRegion samplingRegion("Garbage Collection");
GCPHASE(Collect);
ASSERT(globalData()->apiLock().currentThreadIsHoldingLock());
RELEASE_ASSERT(globalData()->identifierTable == wtfThreadData().currentIdentifierTable());
ASSERT(m_isSafeToCollect);
JAVASCRIPTCORE_GC_BEGIN();
RELEASE_ASSERT(m_operationInProgress == NoOperation);
m_operationInProgress = Collection;
m_activityCallback->willCollect();
double lastGCStartTime = WTF::currentTime();
if (lastGCStartTime - m_lastCodeDiscardTime > minute) {
deleteAllCompiledCode();
m_lastCodeDiscardTime = WTF::currentTime();
}
{
GCPHASE(Canonicalize);
m_objectSpace.canonicalizeCellLivenessData();
}
markRoots();
{
GCPHASE(ReapingWeakHandles);
m_objectSpace.reapWeakSets();
}
JAVASCRIPTCORE_GC_MARKED();
{
m_blockSnapshot.resize(m_objectSpace.blocks().set().size());
MarkedBlockSnapshotFunctor functor(m_blockSnapshot);
m_objectSpace.forEachBlock(functor);
}
copyBackingStores();
{
GCPHASE(FinalizeUnconditionalFinalizers);
finalizeUnconditionalFinalizers();
}
{
GCPHASE(finalizeSmallStrings);
m_globalData->smallStrings.finalizeSmallStrings();
}
{
GCPHASE(DeleteCodeBlocks);
deleteUnmarkedCompiledCode();
}
{
GCPHASE(DeleteSourceProviderCaches);
m_globalData->clearSourceProviderCaches();
}
if (sweepToggle == DoSweep) {
SamplingRegion samplingRegion("Garbage Collection: Sweeping");
GCPHASE(Sweeping);
m_objectSpace.sweep();
m_objectSpace.shrink();
}
m_sweeper->startSweeping(m_blockSnapshot);
m_bytesAbandoned = 0;
{
GCPHASE(ResetAllocators);
m_objectSpace.resetAllocators();
}
size_t currentHeapSize = size();
if (Options::gcMaxHeapSize() && currentHeapSize > Options::gcMaxHeapSize())
HeapStatistics::exitWithFailure();
m_sizeAfterLastCollect = currentHeapSize;
// To avoid pathological GC churn in very small and very large heaps, we set
// the new allocation limit based on the current size of the heap, with a
// fixed minimum.
size_t maxHeapSize = max(minHeapSize(m_heapType, m_ramSize), proportionalHeapSize(currentHeapSize, m_ramSize));
m_bytesAllocatedLimit = maxHeapSize - currentHeapSize;
m_bytesAllocated = 0;
double lastGCEndTime = WTF::currentTime();
m_lastGCLength = lastGCEndTime - lastGCStartTime;
if (Options::recordGCPauseTimes())
HeapStatistics::recordGCPauseTime(lastGCStartTime, lastGCEndTime);
RELEASE_ASSERT(m_operationInProgress == Collection);
m_operationInProgress = NoOperation;
JAVASCRIPTCORE_GC_END();
if (Options::useZombieMode())
zombifyDeadObjects();
if (Options::objectsAreImmortal())
markDeadObjects();
if (Options::showObjectStatistics())
HeapStatistics::showObjectStatistics(this);
}