内存太小了，只能用swap来顶替了。。

几条命令就好了

$ sudo swapoff -a

$ sudo dd if=/dev/zero of=/swapfile bs=1G count=8
if = input file
of = output file
bs = block size
count = multiplier of blocks

$ sudo mkswap /swapfile

$ sudo swapon /swapfile

$ grep SwapTotal /proc/meminfo