Am looking at root drive.
Can I /boot (ext4), / (btrfs),
or do I need swap also?
Read the manual page "man swapon":
swapon may not work correctly when using a swap file with
some versions of btrfs.
Thus if you want to allow the kernel to swap, then using a
swap file that resides on btrfs might not be an option.
Many systems get along just fine without any swap space
(neither a file nor a partition.) Yet the option to use
swap space can be very convenient, even on a system
which has "plenty" of RAM. This is especially true for Fedora,
where a default desktop can have more than 100 processes,
and where Xorg, a mail client, and a web browser deal with
hundreds of megabytes of space at a time.
For instance, my lightly-loaded desktop box has 4GB RAM but
/usr/bin/top says 21MB of swap space is in use.
If possible, then you should consider putting a swap *file*
of 30MB to 80MB on your /boot partition.
Otherwise, from time to time some of your running processes
will find that malloc() fails, even for "small" amounts;
and many processes don't react well when malloc() fails.
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