Exemplo n.º 1
0
SmallLine* Heap::allocateSmallLineSlowCase(std::lock_guard<StaticMutex>& lock, size_t smallSizeClass)
{
    m_isAllocatingPages = true;

    SmallPage* page = [this]() {
        if (m_smallPages.size())
            return m_smallPages.pop();
        
        SmallPage* page = m_vmHeap.allocateSmallPage();
        vmAllocatePhysicalPages(page->begin()->begin(), vmPageSize);
        return page;
    }();

    SmallLine* line = page->begin();
    Vector<SmallLine*>& smallLines = m_smallLines[smallSizeClass];
    for (auto it = line + 1; it != page->end(); ++it)
        smallLines.push(it);

    BASSERT(!line->refCount(lock));
    page->setSmallSizeClass(smallSizeClass);
    page->ref(lock);
    return line;
}
Exemplo n.º 2
0
void Heap::allocateSmallBumpRanges(std::lock_guard<StaticMutex>& lock, size_t sizeClass, BumpAllocator& allocator, BumpRangeCache& rangeCache)
{
    BASSERT(!rangeCache.size());
    SmallPage* page = allocateSmallPage(lock, sizeClass);
    SmallLine* lines = page->begin();

    // Due to overlap from the previous line, the last line in the page may not be able to fit any objects.
    size_t end = SmallPage::lineCount;
    if (!m_smallLineMetadata[sizeClass][SmallPage::lineCount - 1].objectCount)
        --end;

    // Find a free line.
    for (size_t lineNumber = 0; lineNumber < end; ++lineNumber) {
        if (lines[lineNumber].refCount(lock))
            continue;

        // In a fragmented page, some free ranges might not fit in the cache.
        if (rangeCache.size() == rangeCache.capacity()) {
            m_smallPagesWithFreeLines[sizeClass].push(page);
            return;
        }

        LineMetadata& lineMetadata = m_smallLineMetadata[sizeClass][lineNumber];
        char* begin = lines[lineNumber].begin() + lineMetadata.startOffset;
        unsigned short objectCount = lineMetadata.objectCount;
        lines[lineNumber].ref(lock, lineMetadata.objectCount);
        page->ref(lock);

        // Merge with subsequent free lines.
        while (++lineNumber < end) {
            if (lines[lineNumber].refCount(lock))
                break;

            LineMetadata& lineMetadata = m_smallLineMetadata[sizeClass][lineNumber];
            objectCount += lineMetadata.objectCount;
            lines[lineNumber].ref(lock, lineMetadata.objectCount);
            page->ref(lock);
        }

        if (!allocator.canAllocate())
            allocator.refill({ begin, objectCount });
        else
            rangeCache.push({ begin, objectCount });
    }
}