Well, I believe that Fork-friendly GC is the same as Paging-friendly GC -
i.e., after a fork(), the memory is not copied into two different processes
until it is modified. So, even if a process allocates and modifies only a
small percentage of memory, the allocations might trigger the GC, which
means that all the memory is going to be swept and modified - and thus
copied.

The problem is, of course, that this is very process and/or programm
specific - it makes sense for the 24 Apache child processes to do GC, but it
is a waste of time for a forked BASH script processes that is going to
exec() after just a few lines.

The best solution I see here is to abandon the fork()-ing alltogether -
either things are run in the same process, only different threads, or
completely new processes are started (though one can only do that on Windows
platform, not on *NIX - AFAIK).

 - Tom