spin locks prevent forward grantees, e.g. when the thread is scheduled out (or serves an interrupt), no other thread can make progress. Lock free allows progres

spin locks prevent forward grantees, e.g. when the thread is scheduled out (or serves an interrupt), no other thread can make progress. Lock free allows progress - there is no exclusivity. Of course if working on the kernel and controlling the scheduler, etc. the restriction does not apply immediately. Realistically though, lots of lock free employs copy-on-write or rcu.