[squid-users] mallinfo() vs. sbrk()

I remember reading somewhere (can't forget where, and I may be
incorrect) that when available, sbrk is a more reliable indication of
memory use for squid than mallinfo(). However, I'm seeing this on a box;

        Process Data Segment Size via sbrk(): 1040844 KB
        Maximum Resident Size: 0 KB
        Page faults with physical i/o: 0
Memory usage for squid via mallinfo():
        Total space in arena: 1621452 KB
        Ordinary blocks: 1620888 KB 8820 blks
        Small blocks: 0 KB 0 blks
        Holding blocks: 20928 KB 4 blks
        Free Small blocks: 0 KB
        Free Ordinary blocks: 563 KB
        Total in use: 1641816 KB 100%
        Total free: 563 KB 0%
        Total size: 1642380 KB
Memory accounted for:
        Total accounted: 1565651 KB

As you can see, sbrk() is considerably less than total size via
mallinfo(). Is this unusual? Any thoughts about which is better, if
both are available?

Thanks,

--
Mark Nottingham       mnot_at_yahoo-inc.com