VM and jailed processes

[Andrew]

Ok, I'm a bit fuzzy on some of the details, so take it easy. ;-)

It's my understanding that if there is more than one instance of a
specific application running, then portions of the code are shared in
memory. I would assume that would apply to dynamically linked
applications as well; i.e. if two different applications are linked
against the same library, the given code exists in only one location in
memory. Is this correct?

The second portion of my question is, how does this apply to jailed
processes? Looking through the architecture handbook, I did not see any
references to VM, which leads me to believe that the standard rules
apply to jails as well. So, for instance, if I was to provide a hosting
service with numerous instances of Apache running in individual jails,
could I assume that base memory usage (ie idle, not serving requests)
would increase at a roughly linear rate?

Lastly, if this is a question perhaps more appropriate for hackers@,
please correct me. 

Thanks, 
-Andrew