Probably a bit of a silly question but if I mmap a file of 100kB in 5
different processes (using MAP_FILE|MAP_SHARED), would my memory footprint
(in terms of "real" memory usage) be
 a. 5*100kB = 500kB?
 b. a once off allocation of 100kB which is paged for the various processes?
 c. a variable amount per process depending on how it's accessed in the
code?

The man page for mmap is not terribly clear on this and I can't find another
resources which answers this question so any help would be appreciated.

Regards
 Stuart