There's a bit of a terminology confusion here. When they say "spinlock", most people mean a pure spinlock that spins forever until it succeeds. "Mutex" on the

There's a bit of a terminology confusion here. When they say "spinlock", most people mean a pure spinlock that spins forever until it succeeds. "Mutex" on the other hand might have a fast-path that spins a few times before inserting the thread onto a wait list.