void Heap::collectAllGarbageIfNotDoneRecently()
{
if (!m_fullActivityCallback) {
collectAllGarbage();
return;
}
if (m_fullActivityCallback->didSyncGCRecently()) {
// A synchronous GC was already requested recently so we merely accelerate next collection.
reportAbandonedObjectGraph();
return;
}
m_fullActivityCallback->setDidSyncGCRecently();
collectAllGarbage();
}
void Heap::reportExtraMemoryCostSlowCase(size_t cost)
{
// Our frequency of garbage collection tries to balance memory use against speed
// by collecting based on the number of newly created values. However, for values
// that hold on to a great deal of memory that's not in the form of other JS values,
// that is not good enough - in some cases a lot of those objects can pile up and
// use crazy amounts of memory without a GC happening. So we track these extra
// memory costs. Only unusually large objects are noted, and we only keep track
// of this extra cost until the next GC. In garbage collected languages, most values
// are either very short lived temporaries, or have extremely long lifetimes. So
// if a large value survives one garbage collection, there is not much point to
// collecting more frequently as long as it stays alive.
if (m_extraCost > maxExtraCost && m_extraCost > m_objectSpace.highWaterMark() / 2)
collectAllGarbage();
m_extraCost += cost;
}
void* Heap::allocate(NewSpace::SizeClass& sizeClass)
{
#if COLLECT_ON_EVERY_ALLOCATION
collectAllGarbage();
ASSERT(m_operationInProgress == NoOperation);
#endif
m_operationInProgress = Allocation;
void* result = m_newSpace.allocate(sizeClass);
m_operationInProgress = NoOperation;
if (result)
return result;
if (m_newSpace.waterMark() < m_newSpace.highWaterMark()) {
m_newSpace.addBlock(sizeClass, allocateBlock(sizeClass.cellSize));
return allocate(sizeClass);
}
collect(DoNotSweep);
return allocate(sizeClass);
}
void* Heap::allocateSlowCase(size_t bytes)
{
ASSERT(globalData()->identifierTable == wtfThreadData().currentIdentifierTable());
ASSERT(JSLock::lockCount() > 0);
ASSERT(JSLock::currentThreadIsHoldingLock());
ASSERT(bytes <= MarkedSpace::maxCellSize);
ASSERT(m_operationInProgress == NoOperation);
#if COLLECT_ON_EVERY_SLOW_ALLOCATION
collectAllGarbage();
ASSERT(m_operationInProgress == NoOperation);
#endif
reset(DoNotSweep);
m_operationInProgress = Allocation;
void* result = m_markedSpace.allocate(bytes);
m_operationInProgress = NoOperation;
ASSERT(result);
return result;
}