vm.swappiness = 5 
vm.dirty_background_ratio = 10
vm.dirty_ratio = 5 
vm.dirty_expire_centisecs = 1500
vm.overcommit_memory = 1
vm.overcommit_ratio = 30

vm.min_free_kbytes = 0 

在内存较小的机器上写入 /etc/sysctl.conf   

然后 sysctl -p