Demo: One Fault per Page, Once

A program counting its own page faults around each step.

Run

make
./page_faults

Ask

• 0 for the mmap(), 1024 for the first write, 0 for the second. What happened in each of the 1024?
• After the first write, who translates the addresses: the kernel or the hardware?
• Reading first costs 1024 faults, and writing afterwards costs 1024 again. What did the kernel map on the read, if not a fresh page?