memPool unaccounted

I recently started using squid again after a very long time.
It's good to see some familiar names. Anyway, looking at the
memory footprint I notice something odd:

I started a squid 3.0.STABLE18 in a minimal config (using a Debian-testing
package) in a configuration with just an http_port, no disk cache, and
cache_mem configured to 4MB. The proxy has not served any requests and
is otherwise idle.

Checking the memory usage I see:

Memory accounted for:
        Total accounted: 1850 KB 6%
        memPool accounted: 1850 KB 6%
        memPool unaccounted: 28433 KB 94%
        memPoolAlloc calls: 1447
        memPoolFree calls: 386

I seem to recall that back in the days (2000-2003-ish) the unaccounted
memPool numbers weren't *that* high. Any idea what is using up all this
memory and/or if it can be reduced with some runtime-config options?

-- 
Sincerely,
           Stephen R. van den Berg.
"When you are in it up to your ears, keep your mouth shut."