The meaning of volatile keyword is not "do not optimize accesses to this variable". Rather, it's "this value may change at any time". Let's say you have a vari

The meaning of volatile keyword is not "do not optimize accesses to this variable". Rather, it's "this value may change at any time". Let's say you have a variable that's used as a flag for communication between two threads. Protecting it with spin_locks inside a thread that checks the flag repeatedly inside a loop is not going to prevent compiler from optimizing that access away -- because as far as the compiler is concerned, value of that flag does not change inside that loop -- period. It appears that the real recommendation of the article is to process shared data in special functions that access them by dereferencing a pointer. I don't see how that's more efficient/effective for simple cases like described above than declaring a volatile variable.