This is true, but the concurrent work stealing queues and such that are commonly used for such purposes aren't usually textbook C-style linked lists. They (at least in the case of Crossbeam, don't have experience with others) allocate smaller contiguous blocks of items which are then linked together with pointers. This reduces overhead a lot more than the xor trick does while also improving cache behaviour. Also as you mentioned they're already only singly linked in the first place.