[Serusers] Why does the memory occupied by SER process not decrese?

I am using ser 0.8.14. I wrote a program to test the stability of SER. The scenario like this caller----SER----callee. Caller program will send INVITE continuously.Callee program answer each call proxyed by SER. And then Caller program send BYE to finish the call. I run 'top' tool in linux to monitor the usage of memory and cup by SER. I found that with the call establishing speed increasing, the memory occupied by SER process increasing too.After I shut down the test program, the memory ocupied by SER process didn't decrease. Can anyone tell me why? And Does is mean memory leak? Best regards! Karman Wu ---------------------------------------------- 21CNÓÊÏäÈ«ÃæÉýG http://mail.21cn.com/huodong/0504/mail/ ²ÊÆÁÊÖ»ú°×ËÍÀ²!žÏ¿ìÀŽÄÃ! http://qipai.g.21cn.com ÖǻێóÌôÕœŸÍÔڵ͌۶᱊ http://super.21cn.com/ ÌåÑéÁíÀàÔŒ»á£¬žÐÊܱðÑùÀËÂþ http://y.21cn.com/club/ СÁéÍš¶ÌÐÅÖÐÐÄ£¬¶ÌÐÅ÷ÈÁŠÎÞŒ« http://pas.21cn.com/ È«ÄÜÁÄ2005°æÉÁÁÁµÇ³¡£¡ http://callme.21cn.com