Support for paging of anonymous memory (swap)

modulename: page_io.ko

configname: CONFIG_SWAP

Linux Kernel Configuration
└─>Memory Management options
└─>Support for paging of anonymous memory (swap)
In linux kernel since version 2.6.12  
This option allows you to choose whether you want to have support
for so called swap devices or swap files in your kernel that are
used to provide more virtual memory than the actual RAM present
in your computer. If unsure say Y.

source code:
mm/