ok, thanks for the link.
i actually looked also at the free memory my system reported (with free or xosview), and there I saw that the double size was used. i'll look at that in detail to assure that i looked correctly.

Update: Ok, now that I checked with a qx{free} directly in the script I saw that the memory size didn't double. *phooey* thanks again. don't know at what I was looking before.

Unfortunately that means I can dump Apache::SizeLimit. Maybe I can at least use MAX_PROCESS_SIZE instead of MAX_UNSHARED_SIZE. bummer.