- Don’t put flags in the high bits of the aux pointer. Instead if an object has flags, it’ll have a fatter header. Most objects don’t have flags. - Give up on

- Don’t put flags in the high bits of the aux pointer. Instead if an object has flags, it’ll have a fatter header. Most objects don’t have flags. - Give up on lock freedom of atomic pointers. This is a fun one because theoretically, it’s worse. But it comes with a net perf improvement because there’s no need to check the low bit of lowers.