C++ CopiedBlock::next方法代码示例

void CopiedSpace::didStartFullCollection()
{
    ASSERT(heap()->operationInProgress() == FullCollection);

    ASSERT(m_fromSpace->isEmpty());

    for (CopiedBlock* block = m_toSpace->head(); block; block = block->next())
        block->didSurviveGC();

    for (CopiedBlock* block = m_oversizeBlocks.head(); block; block = block->next())
        block->didSurviveGC();
}

size_t CopiedSpace::capacity()
{
    size_t calculatedCapacity = 0;

    for (CopiedBlock* block = m_toSpace->head(); block; block = block->next())
        calculatedCapacity += block->capacity();

    for (CopiedBlock* block = m_fromSpace->head(); block; block = block->next())
        calculatedCapacity += block->capacity();

    for (CopiedBlock* block = m_oversizeBlocks.head(); block; block = block->next())
        calculatedCapacity += block->capacity();

    return calculatedCapacity;
}

size_t CopiedSpace::size()
{
    size_t calculatedSize = 0;

    for (CopiedBlock* block = m_toSpace->head(); block; block = block->next())
        calculatedSize += block->size();

    for (CopiedBlock* block = m_fromSpace->head(); block; block = block->next())
        calculatedSize += block->size();

    for (CopiedBlock* block = m_oversizeBlocks.head(); block; block = block->next())
        calculatedSize += block->size();

    return calculatedSize;
}

void CopiedSpace::startedCopying()
{
    std::swap(m_fromSpace, m_toSpace);

    m_blockFilter.reset();
    m_allocator.resetCurrentBlock();

    CopiedBlock* next = 0;
    size_t totalLiveBytes = 0;
    size_t totalUsableBytes = 0;
    for (CopiedBlock* block = m_fromSpace->head(); block; block = next) {
        next = block->next();
        if (!block->isPinned() && block->canBeRecycled()) {
            recycleEvacuatedBlock(block);
            continue;
        }
        totalLiveBytes += block->liveBytes();
        totalUsableBytes += block->payloadCapacity();
    }

    CopiedBlock* block = m_oversizeBlocks.head();
    while (block) {
        CopiedBlock* next = block->next();
        if (block->isPinned()) {
            m_blockFilter.add(reinterpret_cast<Bits>(block));
            totalLiveBytes += block->payloadCapacity();
            totalUsableBytes += block->payloadCapacity();
            block->didSurviveGC();
        } else {
            m_oversizeBlocks.remove(block);
            m_blockSet.remove(block);
            m_heap->blockAllocator().deallocateCustomSize(CopiedBlock::destroy(block));
        } 
        block = next;
    }

    double markedSpaceBytes = m_heap->objectSpace().capacity();
    double totalFragmentation = ((double)totalLiveBytes + markedSpaceBytes) / ((double)totalUsableBytes + markedSpaceBytes);
    m_shouldDoCopyPhase = totalFragmentation <= Options::minHeapUtilization();
    if (!m_shouldDoCopyPhase)
        return;

    ASSERT(m_shouldDoCopyPhase);
    ASSERT(!m_inCopyingPhase);
    ASSERT(!m_numberOfLoanedBlocks);
    m_inCopyingPhase = true;
}

void CopiedSpace::didStartFullCollection()
{
    ASSERT(heap()->operationInProgress() == FullCollection);
    ASSERT(m_oldGen.fromSpace->isEmpty());
    ASSERT(m_newGen.fromSpace->isEmpty());

#ifndef NDEBUG
    for (CopiedBlock* block = m_newGen.toSpace->head(); block; block = block->next())
        ASSERT(!block->liveBytes());

    for (CopiedBlock* block = m_newGen.oversizeBlocks.head(); block; block = block->next())
        ASSERT(!block->liveBytes());
#endif

    for (CopiedBlock* block = m_oldGen.toSpace->head(); block; block = block->next())
        block->didSurviveGC();

    for (CopiedBlock* block = m_oldGen.oversizeBlocks.head(); block; block = block->next())
        block->didSurviveGC();
}

static bool isBlockListPagedOut(double deadline, DoublyLinkedList<CopiedBlock>* list)
{
    unsigned itersSinceLastTimeCheck = 0;
    CopiedBlock* current = list->head();
    while (current) {
        current = current->next();
        ++itersSinceLastTimeCheck;
        if (itersSinceLastTimeCheck >= Heap::s_timeCheckResolution) {
            double currentTime = WTF::monotonicallyIncreasingTime();
            if (currentTime > deadline)
                return true;
            itersSinceLastTimeCheck = 0;
        }
    }

    return false;
}

void GCThreadSharedData::didStartCopying()
{
    {
        SpinLockHolder locker(&m_copyLock);
        if (m_vm->heap.operationInProgress() == EdenCollection) {
            // Reset the vector to be empty, but don't throw away the backing store.
            m_blocksToCopy.shrink(0);
            for (CopiedBlock* block = m_copiedSpace->m_newGen.fromSpace->head(); block; block = block->next())
                m_blocksToCopy.append(block);
        } else {
            ASSERT(m_vm->heap.operationInProgress() == FullCollection);
            WTF::copyToVector(m_copiedSpace->m_blockSet, m_blocksToCopy);
        }
        m_copyIndex = 0;
    }

    // We do this here so that we avoid a race condition where the main thread can 
    // blow through all of the copying work before the GCThreads fully wake up. 
    // The GCThreads then request a block from the CopiedSpace when the copying phase 
    // has completed, which isn't allowed.
    for (size_t i = 0; i < m_gcThreads.size(); i++)
        m_gcThreads[i]->copyVisitor()->startCopying();

    startNextPhase(Copy);
}