Adding file swap on btrfs

Monday, 19 December 2022

I've just installed f37 on a new lenovo x1 carbon.
One thing, the installation didn't setup any swap (other than zswap).

After a bit of reading I found
sudo btrfs filesystem mkswapfile -s 32G /swapfile
But:
 sudo swapon -v /swapfile
swapon: /swapfile: found signature [pagesize=4096, signature=swap]
swapon: /swapfile: pagesize=4096, swapsize=1073741824, devsize=34359738368

Although I created 32G swapfile, only 1G is used.
swapon
NAME       TYPE       SIZE USED PRIO
/dev/zram0 partition    8G 6.3M  100
/swapfile  file      1024M   0B   -2

What's wrong?

Thanks,
Neal