A method to update a data structure is disclosed. The method receives a write thread, and sets a data structure indicator to indicate that the data structure is unusable. The method creates (N) thread indicators, and assigns each of said (N) indicators to a different one of said (N) threads. Upon return to the thread dispatcher, the (i)th thread sees the data structure indicator which shows that the data structure is unusable. The method then sets the (i)th thread indicator to indicate that upon subsequent dispatches the (i)th thread will see the data structure indicator that shows that the data structure is unusable. After each of the (N) threads has seen the data structure indicator marking the data structure as unusable, the method sets the data structure indicator to indicate that the data structure is invalid, updates the data structure, and sets the data structure indicator to indicate that the data structure is valid.