Hi
fpm workers share APC cache between them, memory is added to RES and SHR, looking at the usage it seems you have about 128 Mb (maybe a bit more) APC dedicated for opcode and variable caching.
If you are affraid that APC is leaking RAM - try flushing its cache from apc control panel and see, you can set pm.max_requests to some reasonable value to make fpm workers restart after serving max requests.
Alternatively you can try any other opcode cache : eaccelerator (abandonware, but works on 5.4), xcache (works fine! has variable cache), zend opcache (opensourced not very long time ago, very good!), i am hapy with combo zendopcache + xcache as variable cacher
fpm workers share APC cache between them, memory is added to RES and SHR, looking at the usage it seems you have about 128 Mb (maybe a bit more) APC dedicated for opcode and variable caching.
If you are affraid that APC is leaking RAM - try flushing its cache from apc control panel and see, you can set pm.max_requests to some reasonable value to make fpm workers restart after serving max requests.
Alternatively you can try any other opcode cache : eaccelerator (abandonware, but works on 5.4), xcache (works fine! has variable cache), zend opcache (opensourced not very long time ago, very good!), i am hapy with combo zendopcache + xcache as variable cacher