void Heap::allocateMediumBumpRanges(std::lock_guard<StaticMutex>& lock, size_t sizeClass, BumpAllocator& allocator, BumpRangeCache& rangeCache)
{
MediumPage* page = allocateMediumPage(lock, sizeClass);
BASSERT(!rangeCache.size());
MediumLine* 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 = MediumPage::lineCount;
if (!m_mediumLineMetadata[sizeClass][MediumPage::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_mediumPagesWithFreeLines[sizeClass].push(page);
return;
}
LineMetadata& lineMetadata = m_mediumLineMetadata[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_mediumLineMetadata[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 });
}
}
void* Allocator::reallocate(void* object, size_t newSize)
{
if (!m_isBmallocEnabled)
return realloc(object, newSize);
void* result = allocate(newSize);
if (!object)
return result;
size_t oldSize = 0;
switch (objectType(object)) {
case Small: {
SmallPage* page = SmallPage::get(SmallLine::get(object));
oldSize = objectSize(page->sizeClass());
break;
}
case Medium: {
MediumPage* page = MediumPage::get(MediumLine::get(object));
oldSize = objectSize(page->sizeClass());
break;
}
case Large: {
std::lock_guard<StaticMutex> lock(PerProcess<Heap>::mutex());
LargeObject largeObject(object);
oldSize = largeObject.size();
break;
}
case XLarge: {
std::lock_guard<StaticMutex> lock(PerProcess<Heap>::mutex());
Range range = PerProcess<Heap>::getFastCase()->findXLarge(lock, object);
RELEASE_BASSERT(range);
oldSize = range.size();
break;
}
}
size_t copySize = std::min(oldSize, newSize);
memcpy(result, object, copySize);
m_deallocator.deallocate(object);
return result;
}
void Heap::deallocateMediumLine(std::lock_guard<StaticMutex>& lock, MediumLine* line)
{
BASSERT(!line->refCount(lock));
MediumPage* page = MediumPage::get(line);
size_t refCount = page->refCount(lock);
page->deref(lock);
switch (refCount) {
case MediumPage::lineCount: {
// First free line in the page.
m_mediumPagesWithFreeLines[page->sizeClass()].push(page);
break;
}
case 1: {
// Last free line in the page.
m_mediumPages.push(page);
m_scavenger.run();
break;
}
}
}
MediumPage* Heap::allocateMediumPage(std::lock_guard<StaticMutex>& lock, size_t sizeClass)
{
Vector<MediumPage*>& mediumPagesWithFreeLines = m_mediumPagesWithFreeLines[sizeClass];
while (mediumPagesWithFreeLines.size()) {
MediumPage* page = mediumPagesWithFreeLines.pop();
if (!page->refCount(lock) || page->sizeClass() != sizeClass) // Page was promoted to the pages list.
continue;
return page;
}
MediumPage* page = [this, sizeClass]() {
if (m_mediumPages.size())
return m_mediumPages.pop();
m_isAllocatingPages = true;
return m_vmHeap.allocateMediumPage();
}();
page->setSizeClass(sizeClass);
return page;
}
MediumLine* Heap::allocateMediumLineSlowCase(std::lock_guard<StaticMutex>& lock)
{
m_isAllocatingPages = true;
MediumPage* page = [this]() {
if (m_mediumPages.size())
return m_mediumPages.pop();
MediumPage* page = m_vmHeap.allocateMediumPage();
vmAllocatePhysicalPages(page->begin()->begin(), vmPageSize);
return page;
}();
MediumLine* line = page->begin();
for (auto it = line + 1; it != page->end(); ++it)
m_mediumLines.push(it);
page->ref(lock);
return line;
}
