创建文件：

# fallocate -l 4G /swapfile

# chmod 600 /swapfile

# mkswap /swapfile
# swapon /swapfile

编辑/etc/fstab文件。添加：/swapfile none swap defaults 0 0

编辑/etc/mkinitcpio.conf文件：
HOOKS="... block lvm2 resume filesystems ..."
# mkinitcpio -p linux

# filefrag -v /swapfile

查找偏移指针：

Filesystem type is: ef53

File size of /swapfile is 4294967296 (1048576 blocks of 4096 bytes)

ext:     logical_offset:        physical_offset: length:   expected: flags:

0:        0..       0:      ..     38912:      1:

1:        1..   22527:      38913..     61439:  22527:             unwritten

2:    22528..   53247:     899072..    929791:  30720:      61440: unwritten

# ls -l /dev/disk/by-uuid/ 查看swapfile文件所在盘的UUID。
lrwxrwxrwx 1 root root 10 Aug  8 19:22 415bb7cf-5a71-4481-a832-c789643ce12c -> ../../sda4

GRUB配置：

# vim /etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT="resume=/dev/disk/by-uuid/415bb7cf-5a71-4481-a832-c789643ce12c resume_offset= quiet"

参考：https://wiki.archlinux.org/index.php/Hibernate#Hibernation_into_swap_file

https://wiki.archlinux.org/index.php/Swap#Swap_file