RCU - write side

1) Copy the data structure to be updated
Leaving the current one in place

2) Make changes to the copy

3) Adjust pointer to new, updated copy

4) Call:

void call_rcu(struct rcu_head *head,
              void (*callback)(void *arg),
              void *arg);

5) After all processors have scheduled
callback() will be called
It can free the old structure