Swap partition usage adjustment

Swap partition usage adjustment (the set value indicates how much the physical memory usage reaches, start using Swap)

#临时修改
sysctl vm.swappiness=60
#永久修改，修改的值意味着当物理内存使用达到60%后，就使用swap
vim /etc/sysctl.conf
vm.swappiness = 60
sysctl -p /etc/sysctl.conf
#释放Swap
swapoff -a
swapon -a