> (In your first test, you were still performing the mapping operations, 
> you just weren't faulting in any pages except the first one.)

There was no fault even in the first mapping.  And since the first one
isn't unmapped (ptr[0] is 0xdeadbeef), number of mapping increases on
each outer iteration.  So, the time difference in the first test is
also due to map entry merging, I guess.

enami.