关于swap的介绍，挺详细，值得一看： https://help.ubuntu.com/community/SwapFaq
其中比较常用的就是调swappiness值
- To check the swappiness value
cat /proc/sys/vm/swappiness - To change the swappiness value A temporary change (lost on reboot) with a swappiness value of 10 can be made with
sudo sysctl vm.swappiness=10 - To make a change permanent, edit the configuration file with your favorite editor:
sudo gedit /etc/sysctl.conf - Search for vm.swappiness and change its value as desired. If vm.swappiness does not exist, add it to the end of the file like so:
vm.swappiness=10内存如果够大，这里完全可以设为0，或者干脆干掉swap分区 Save the file and reboot.