Statically allocated memory can still OOM on access, due to overcommit and lazy page table population. What you really want is mlockall(2) (probably with MCL_CURRENT|MCL_ONFAULT followed by madvise with MADV_POPULATE_*)

oops MCL_ONFAULT kinda does the opposite of what I wanted - I think if you omit that you can skip the madvise, and mlockall will populate everything for you.