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()->identifierTable == wtfThreadData().currentIdentifierTable());
ASSERT(m_isSafeToCollect);
JAVASCRIPTCORE_GC_BEGIN();
m_activityCallback->willCollect();
double lastGCStartTime = WTF::currentTime();
if (lastGCStartTime - m_lastCodeDiscardTime > minute) {
discardAllCompiledCode();
m_lastCodeDiscardTime = WTF::currentTime();
}
#if ENABLE(GGC)
bool fullGC = sweepToggle == DoSweep;
if (!fullGC)
fullGC = (capacity() > 4 * m_sizeAfterLastCollect);
#else
bool fullGC = true;
#endif
{
GCPHASE(Canonicalize);
canonicalizeCellLivenessData();
}
markRoots(fullGC);
{
GCPHASE(FinalizeUnconditionalFinalizers);
finalizeUnconditionalFinalizers();
}
{
GCPHASE(FinalizeWeakHandles);
m_weakSet.sweep();
m_globalData->smallStrings.finalizeSmallStrings();
}
JAVASCRIPTCORE_GC_MARKED();
{
GCPHASE(ResetAllocator);
resetAllocators();
}
{
GCPHASE(DeleteCodeBlocks);
m_dfgCodeBlocks.deleteUnmarkedJettisonedCodeBlocks();
}
if (sweepToggle == DoSweep) {
SamplingRegion samplingRegion("Garbage Collection: Sweeping");
GCPHASE(Sweeping);
sweep();
m_objectSpace.shrink();
m_weakSet.shrink();
}
// To avoid pathological GC churn in large heaps, we set the new allocation
// limit to be the current size of the heap. This heuristic
// is a bit arbitrary. Using the current size of the heap after this
// collection gives us a 2X multiplier, which is a 1:1 (heap size :
// new bytes allocated) proportion, and seems to work well in benchmarks.
size_t newSize = size();
if (fullGC) {
m_sizeAfterLastCollect = newSize;
m_bytesAllocatedLimit = max(newSize, m_minBytesPerCycle);
}
m_bytesAllocated = 0;
double lastGCEndTime = WTF::currentTime();
m_lastGCLength = lastGCEndTime - lastGCStartTime;
JAVASCRIPTCORE_GC_END();
}
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);
}
NEVER_INLINE void Heap::collectImpl(HeapOperation collectionType, void* stackOrigin, void* stackTop, MachineThreads::RegisterState& calleeSavedRegisters)
{
#if ENABLE(ALLOCATION_LOGGING)
dataLogF("JSC GC starting collection.\n");
#endif
double before = 0;
if (Options::logGC()) {
dataLog("[GC: ");
before = currentTimeMS();
}
SamplingRegion samplingRegion("Garbage Collection");
if (vm()->typeProfiler()) {
DeferGCForAWhile awhile(*this);
vm()->typeProfilerLog()->processLogEntries(ASCIILiteral("GC"));
}
RELEASE_ASSERT(!m_deferralDepth);
ASSERT(vm()->currentThreadIsHoldingAPILock());
RELEASE_ASSERT(vm()->atomicStringTable() == wtfThreadData().atomicStringTable());
ASSERT(m_isSafeToCollect);
JAVASCRIPTCORE_GC_BEGIN();
RELEASE_ASSERT(m_operationInProgress == NoOperation);
suspendCompilerThreads();
willStartCollection(collectionType);
GCPHASE(Collect);
double gcStartTime = WTF::monotonicallyIncreasingTime();
if (m_verifier) {
// Verify that live objects from the last GC cycle haven't been corrupted by
// mutators before we begin this new GC cycle.
m_verifier->verify(HeapVerifier::Phase::BeforeGC);
m_verifier->initializeGCCycle();
m_verifier->gatherLiveObjects(HeapVerifier::Phase::BeforeMarking);
}
flushOldStructureIDTables();
stopAllocation();
flushWriteBarrierBuffer();
markRoots(gcStartTime, stackOrigin, stackTop, calleeSavedRegisters);
if (m_verifier) {
m_verifier->gatherLiveObjects(HeapVerifier::Phase::AfterMarking);
m_verifier->verify(HeapVerifier::Phase::AfterMarking);
}
JAVASCRIPTCORE_GC_MARKED();
if (vm()->typeProfiler())
vm()->typeProfiler()->invalidateTypeSetCache();
reapWeakHandles();
pruneStaleEntriesFromWeakGCMaps();
sweepArrayBuffers();
snapshotMarkedSpace();
copyBackingStores();
finalizeUnconditionalFinalizers();
removeDeadCompilerWorklistEntries();
deleteUnmarkedCompiledCode();
deleteSourceProviderCaches();
notifyIncrementalSweeper();
rememberCurrentlyExecutingCodeBlocks();
resetAllocators();
updateAllocationLimits();
didFinishCollection(gcStartTime);
resumeCompilerThreads();
if (m_verifier) {
m_verifier->trimDeadObjects();
m_verifier->verify(HeapVerifier::Phase::AfterGC);
}
if (Options::logGC()) {
double after = currentTimeMS();
dataLog(after - before, " ms]\n");
}
}