It sounds like you have networking specifically in mind. Certainly,
file serving and routing are obvious applications to benefit from this
(they're what I had in mind too), but also general I/O in all
applications is likely to benefit. There is a potential reduction in
swapping too (see "Swapping Benefits").
Although this is where you'd see very noticable benefits, I've been
profiling the SparcLinux kernel a bit lately and a lot of copy/zero
happens in the mm subsystem and should not be ignored.
In fact, if your copy/zero is the best it can be, fork/exec/exit
become very quick operations even though they cause operations to be
performed on a processes entire page table.
Later,
David S. Miller
davem@caip.rutgers.edu