void BlockDirectory::endMarking()
{
m_allocated.clearAll();
// It's surprising and frustrating to comprehend, but the end-of-marking flip does not need to
// know what kind of collection it is. That knowledge is already encoded in the m_markingXYZ
// vectors.
if (!Options::tradeDestructorBlocks() && needsDestruction()) {
ASSERT(m_empty.isEmpty());
m_canAllocateButNotEmpty = m_live & ~m_markingRetired;
} else {
m_empty = m_live & ~m_markingNotEmpty;
m_canAllocateButNotEmpty = m_live & m_markingNotEmpty & ~m_markingRetired;
}
if (needsDestruction()) {
// There are some blocks that we didn't allocate out of in the last cycle, but we swept them. This
// will forget that we did that and we will end up sweeping them again and attempting to call their
// destructors again. That's fine because of zapping. The only time when we cannot forget is when
// we just allocate a block or when we move a block from one size class to another. That doesn't
// happen here.
m_destructible = m_live;
}
if (false) {
dataLog("Bits for ", m_cellSize, ", ", m_attributes, " after endMarking:\n");
dumpBits(WTF::dataFile());
}
}
void MarkedAllocator::endMarking()
{
m_allocated.clearAll();
// It's surprising and frustrating to comprehend, but the end-of-marking flip does not need to
// know what kind of collection it is. That knowledge is already encoded in the m_markingXYZ
// vectors.
if (needsDestruction()) {
// If blocks need destruction then nothing is empty! This is a correct assertion but may
// become wrong once we go full concurrent: when we create a new block, it will flicker
// into the empty set for a tiny moment. On the other hand, this code is likely to be run
// in stopTheWorld.
ASSERT(m_empty.isEmpty());
m_canAllocateButNotEmpty = m_live & ~m_markingRetired;
return;
}
m_empty = m_live & ~m_markingNotEmpty;
m_canAllocateButNotEmpty = m_live & m_markingNotEmpty & ~m_markingRetired;
if (false) {
dataLog("Bits for ", m_cellSize, ", ", m_attributes, " after endMarking:\n");
dumpBits(WTF::dataFile());
}
}
bool MarkedAllocator::shouldStealEmptyBlocksFromOtherAllocators() const
{
return !needsDestruction();
}
