STABLE_NODE_DUP_HEAD  345 mm/ksm.c       	return dup->head == STABLE_NODE_DUP_HEAD;
STABLE_NODE_DUP_HEAD  352 mm/ksm.c       	dup->head = STABLE_NODE_DUP_HEAD;
STABLE_NODE_DUP_HEAD  658 mm/ksm.c       	BUILD_BUG_ON(STABLE_NODE_DUP_HEAD <= &migrate_nodes);
STABLE_NODE_DUP_HEAD  659 mm/ksm.c       	BUILD_BUG_ON(STABLE_NODE_DUP_HEAD >= &migrate_nodes + 1);