void BlockAllocator::blockFreeingThreadMain()
{
size_t currentNumberOfEmptyRegions;
while (!m_blockFreeingThreadShouldQuit) {
// Generally wait for one second before scavenging free blocks. This
// may return early, particularly when we're being asked to quit.
waitForRelativeTime(1.0);
if (m_blockFreeingThreadShouldQuit)
break;
if (m_isCurrentlyAllocating) {
m_isCurrentlyAllocating = false;
continue;
}
// Sleep until there is actually work to do rather than waking up every second to check.
{
MutexLocker locker(m_emptyRegionConditionLock);
SpinLockHolder regionLocker(&m_regionLock);
while (!m_numberOfEmptyRegions && !m_blockFreeingThreadShouldQuit) {
m_regionLock.Unlock();
m_emptyRegionCondition.wait(m_emptyRegionConditionLock);
m_regionLock.Lock();
}
currentNumberOfEmptyRegions = m_numberOfEmptyRegions;
}
size_t desiredNumberOfEmptyRegions = currentNumberOfEmptyRegions / 2;
while (!m_blockFreeingThreadShouldQuit) {
Region* region;
{
SpinLockHolder locker(&m_regionLock);
if (m_numberOfEmptyRegions <= desiredNumberOfEmptyRegions)
region = 0;
else {
region = m_emptyRegions.removeHead();
RELEASE_ASSERT(region);
m_numberOfEmptyRegions--;
}
}
if (!region)
break;
delete region;
}
}
}
void BlockAllocator::blockFreeingThreadMain()
{
while (!m_blockFreeingThreadShouldQuit) {
// Generally wait for one second before scavenging free blocks. This
// may return early, particularly when we're being asked to quit.
waitForRelativeTime(1.0);
if (m_blockFreeingThreadShouldQuit)
break;
if (m_isCurrentlyAllocating) {
m_isCurrentlyAllocating = false;
continue;
}
// Now process the list of free blocks. Keep freeing until half of the
// blocks that are currently on the list are gone. Assume that a size_t
// field can be accessed atomically.
size_t currentNumberOfFreeBlocks = m_numberOfFreeBlocks;
if (!currentNumberOfFreeBlocks)
continue;
size_t desiredNumberOfFreeBlocks = currentNumberOfFreeBlocks / 2;
while (!m_blockFreeingThreadShouldQuit) {
MarkedBlock* block;
{
MutexLocker locker(m_freeBlockLock);
if (m_numberOfFreeBlocks <= desiredNumberOfFreeBlocks)
block = 0;
else {
// FIXME: How do we know this is a MarkedBlock? It could be a CopiedBlock.
block = static_cast<MarkedBlock*>(m_freeBlocks.removeHead());
ASSERT(block);
m_numberOfFreeBlocks--;
}
}
if (!block)
break;
MarkedBlock::destroy(block);
}
}
}
