cache_mem and memory usage

Hi,
I run squid 1.1.2 and set cache_mem 100 and cache_swap 60000.
We have 60G harddisk for cache and these are separated into 3 with equal size.
After changing configuration of this, squid seems to run abnormally.
Its cpuusage is almost 70% for several days.
And when I see information via cachemanager, It says as the following:

    Cache information for squid:
        Storage Swap size: 16996 MB
        Storage Mem size: 86993 KB
    Memory usage for squid via mallinfo():
        Total space in arena: 334833 KB
        Total in use: 295633 KB 88%
        Total free: 39199 KB 12%
    Accounted Memory Usage:
        Total Accounted = 219097 KB

Storage mem size means the used part of cache_mem ?
Why memory usage of mallinfo() is much greter than cache_mem ?
In same case, Total accounted mem is much bigger than cache_mem also ?
What is wrong with squid configuration ?
Please is there anybody who knows this and explains what's wrong
and knows how I should do ?

-Hwang Hyojung

-- 
    *    _  _	  
    ||_|| ||_| 	  Hwang, Hyojung / jung@jean.kotel.co.kr / 82-2-526-5235
  |_|       _|_	  Internet Team  / Multimedia Laboratory / KT R&D Group
           |_|	  137-792, 17 Umyun-Dong, Seocho-Gu, Seoul, Korea