Added Frontswap support
	new file:   Documentation/vm/frontswap.txt
	modified:   Makefile
	modified:   drivers/staging/zcache/zcache-main.c
	modified:   drivers/xen/Kconfig
	modified:   drivers/xen/Makefile
	modified:   drivers/xen/tmem.c
	modified:   fs/buffer.c
	modified:   fs/super.c
	modified:   include/linux/cleancache.h
	new file:   include/linux/frontswap.h
	modified:   include/linux/swap.h
	new file:   include/linux/swapfile.h
	modified:   mm/Kconfig
	modified:   mm/Makefile
	modified:   mm/cleancache.c
	modified:   mm/filemap.c
	new file:   mm/frontswap.c
	modified:   mm/page_io.c
	modified:   mm/swapfile.c
	modified:   mm/truncate.c