pymongo需要关闭链接吗?

现在我用的是pymongo的长链接,因此是不关闭他的,会不会是这个原因导致内存虚高不下呢?

Tasks: 134 total,   1 running, 133 sleeping,   0 stopped,   0 zombie 
Cpu(s):  0.0%us,  0.1%sy,  0.0%ni, 99.9%id,  0.0%wa,  0.0%hi,  0.0%si,  0.0%st 
Mem:  30212128k total, 28318180k used,  1893948k free,   323724k buffers 
Swap:  2104504k total,        0k used,  2104504k free,   189812k cached 


  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND                                                                                                             
  8377 root      20   0 26.5g  26g 4392 S  1.7 91.0 173:10.13 mongos                                                                                                              
 19424 root      20   0  539m 111m  46m S  0.3  0.4  50:35.13 mongod                                                                                                              
 19473 root      20   0  506m  59m  26m S  0.3  0.2  43:01.72 mongod 

再次重申,他没用多少缓存,用的都是实打实的内存(缓存非常少)

# free -m 
             total       used       free     shared    buffers     cached 
Mem:         29504      27658       1845          0        316        185 
-/+ buffers/cache:      27157       2346 
Swap:         2055          0       2055 

求解决,忘高手指点一二,始终受不了啦,没几天就要重启mongos