WF_TTWU
wake_flags |= WF_TTWU;
if (!(flags & WF_TTWU))
SCX_WAKE_TTWU = WF_TTWU,
if (wake_flags & WF_TTWU) {
} else if (wake_flags & WF_TTWU) { /* XXX always ? */
WARN_ON_ONCE(!(wake_flags & WF_TTWU));
if (!(flags & (WF_TTWU | WF_FORK)))
static_assert(WF_TTWU == SD_BALANCE_WAKE);