> (gdb) print *pv_table
> $4 = {pv_next = 0x0, pv_pmap = 0x0, pv_va = 4028600320, pv_flags = 5}
> 
> Does that make any sense? Not to me I have to admit :-)
> 

It means that the page this entry represents is not currently mapped
to a virtual address (though at some point in the past it was mapped
to VA `4028600320').

Even though if a page is not currently mapped to any virtual address, we
still need to retain the `pv_flags' for it, since the page might
linger on a VM object.  In that case, it's possible that it still needs
to be written to its backing store (e.g an mmap'ed file), for which
the page's `modified' bit is consulted.

-pk