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#include "config.h"
#include "MarkedAllocator.h"
#include "DelayedReleaseScope.h"
#include "GCActivityCallback.h"
#include "Heap.h"
#include "IncrementalSweeper.h"
#include "VM.h"
#include <wtf/CurrentTime.h>
namespace JSC {
static bool isListPagedOut(double deadline, DoublyLinkedList<MarkedBlock>& list)
{
unsigned itersSinceLastTimeCheck = 0;
MarkedBlock* block = list.head();
while (block) {
block = block->next();
++itersSinceLastTimeCheck;
if (itersSinceLastTimeCheck >= Heap::s_timeCheckResolution) {
double currentTime = WTF::monotonicallyIncreasingTime();
if (currentTime > deadline)
return true;
itersSinceLastTimeCheck = 0;
}
}
return false;
}
bool MarkedAllocator::isPagedOut(double deadline)
{
if (isListPagedOut(deadline, m_blockList))
return true;
return false;
}
inline void* MarkedAllocator::tryAllocateHelper(size_t bytes)
{
// We need a while loop to check the free list because the DelayedReleaseScope
// could cause arbitrary code to execute and exhaust the free list that we
// thought had elements in it.
while (!m_freeList.head) {
DelayedReleaseScope delayedReleaseScope(*m_markedSpace);
if (m_currentBlock) {
ASSERT(m_currentBlock == m_nextBlockToSweep);
m_currentBlock->didConsumeFreeList();
m_nextBlockToSweep = m_currentBlock->next();
}
MarkedBlock* next;
for (MarkedBlock*& block = m_nextBlockToSweep; block; block = next) {
next = block->next();
MarkedBlock::FreeList freeList = block->sweep(MarkedBlock::SweepToFreeList);
if (!freeList.head) {
block->didConsumeEmptyFreeList();
m_blockList.remove(block);
m_blockList.push(block);
if (!m_lastFullBlock)
m_lastFullBlock = block;
continue;
}
if (bytes > block->cellSize()) {
block->stopAllocating(freeList);
continue;
}
m_currentBlock = block;
m_freeList = freeList;
break;
}
if (!m_freeList.head) {
m_currentBlock = 0;
return 0;
}
}
ASSERT(m_freeList.head);
MarkedBlock::FreeCell* head = m_freeList.head;
m_freeList.head = head->next;
ASSERT(head);
m_markedSpace->didAllocateInBlock(m_currentBlock);
return head;
}
inline void* MarkedAllocator::tryAllocate(size_t bytes)
{
ASSERT(!m_heap->isBusy());
m_heap->m_operationInProgress = Allocation;
void* result = tryAllocateHelper(bytes);
m_heap->m_operationInProgress = NoOperation;
return result;
}
void* MarkedAllocator::allocateSlowCase(size_t bytes)
{
ASSERT(m_heap->vm()->currentThreadIsHoldingAPILock());
#if COLLECT_ON_EVERY_ALLOCATION
if (!m_heap->isDeferred())
m_heap->collectAllGarbage();
ASSERT(m_heap->m_operationInProgress == NoOperation);
#endif
ASSERT(!m_markedSpace->isIterating());
ASSERT(!m_freeList.head);
m_heap->didAllocate(m_freeList.bytes);
void* result = tryAllocate(bytes);
if (LIKELY(result != 0))
return result;
if (m_heap->collectIfNecessaryOrDefer()) {
result = tryAllocate(bytes);
if (result)
return result;
}
ASSERT(!m_heap->shouldCollect());
MarkedBlock* block = allocateBlock(bytes);
ASSERT(block);
addBlock(block);
result = tryAllocate(bytes);
ASSERT(result);
return result;
}
MarkedBlock* MarkedAllocator::allocateBlock(size_t bytes)
{
size_t minBlockSize = MarkedBlock::blockSize;
size_t minAllocationSize = WTF::roundUpToMultipleOf(WTF::pageSize(), sizeof(MarkedBlock) + bytes);
size_t blockSize = std::max(minBlockSize, minAllocationSize);
size_t cellSize = m_cellSize ? m_cellSize : WTF::roundUpToMultipleOf<MarkedBlock::atomSize>(bytes);
if (blockSize == MarkedBlock::blockSize)
return MarkedBlock::create(m_heap->blockAllocator().allocate<MarkedBlock>(), this, cellSize, m_destructorType);
return MarkedBlock::create(m_heap->blockAllocator().allocateCustomSize(blockSize, MarkedBlock::blockSize), this, cellSize, m_destructorType);
}
void MarkedAllocator::addBlock(MarkedBlock* block)
{
// Satisfy the ASSERT in MarkedBlock::sweep.
DelayedReleaseScope delayedReleaseScope(*m_markedSpace);
ASSERT(!m_currentBlock);
ASSERT(!m_freeList.head);
m_blockList.append(block);
m_nextBlockToSweep = m_currentBlock = block;
m_freeList = block->sweep(MarkedBlock::SweepToFreeList);
m_markedSpace->didAddBlock(block);
}
void MarkedAllocator::removeBlock(MarkedBlock* block)
{
if (m_currentBlock == block) {
m_currentBlock = m_currentBlock->next();
m_freeList = MarkedBlock::FreeList();
}
if (m_nextBlockToSweep == block)
m_nextBlockToSweep = m_nextBlockToSweep->next();
if (block == m_lastFullBlock)
m_lastFullBlock = m_lastFullBlock->prev();
m_blockList.remove(block);
}
void MarkedAllocator::reset()
{
m_lastActiveBlock = 0;
m_currentBlock = 0;
m_freeList = MarkedBlock::FreeList();
if (m_heap->operationInProgress() == FullCollection)
m_lastFullBlock = 0;
if (m_lastFullBlock)
m_nextBlockToSweep = m_lastFullBlock->next() ? m_lastFullBlock->next() : m_lastFullBlock;
else
m_nextBlockToSweep = m_blockList.head();
}
} // namespace JSC
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