void MemoryIdler::unmapUnusedStack(size_t retain) {
if (tls_stackSize == 0) {
fetchStackLimits();
}
if (tls_stackSize <= std::max(size_t(1), retain)) {
// covers both missing stack info, and impossibly large retain
return;
}
auto sp = getStackPtr();
assert(sp >= tls_stackLimit);
assert(sp - tls_stackLimit < tls_stackSize);
auto end = (sp - retain) & ~(s_pageSize - 1);
if (end <= tls_stackLimit) {
// no pages are eligible for unmapping
return;
}
size_t len = end - tls_stackLimit;
assert((len & (s_pageSize - 1)) == 0);
if (madvise((void*)tls_stackLimit, len, MADV_DONTNEED) != 0) {
// It is likely that the stack vma hasn't been fully grown. In this
// case madvise will apply dontneed to the present vmas, then return
// errno of ENOMEM. We can also get an EAGAIN, theoretically.
// EINVAL means either an invalid alignment or length, or that some
// of the pages are locked or shared. Neither should occur.
assert(errno == EAGAIN || errno == ENOMEM);
}
}
PyScopedLock::~PyScopedLock() {
#ifdef MUTEX_DEBUG
printf("%p unlocks %p from %s\n", (void*)PyThread_get_thread_ident(), &mutex, getStackSymbol(getStackPtr(2)));
#endif
mutex.unlock();
}
const CStackInstance& CCreatureSet::getStack(SlotID slot) const
{
assert(hasStackAtSlot(slot));
return *getStackPtr(slot);
}