#!/bin/bash

# 2.5G
size=$((2560 * 1024 * 1024))

swap_file="/swapfile"

sudo dd if=/dev/zero of=$swap_file bs=1M count=$((size / 1024 / 1024)) status=progress

sudo chmod 600 $swap_file

sudo mkswap $swap_file

sudo swapon --priority -3 $swap_file

swapon --show

free -h

using this, i got:

cat /proc/swaps
Filename Type Size Used Priority
/dev/block/zram0 partition 3128848 1014124 -2
/swapfile file 2621436 0 -3

so zram is now -2 and swapfile is -3
it can be made as a script and enabled with systemd, something like:

[Unit]
Description=setup swap on startup
After=lxc@android.service

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/bin/setup-swap.sh

[Install]
WantedBy=graphical.target

Thanks! but please do note that with the most recent updates if you create a systemd service to launch right after the lxc service it will break wifi. 

For those reading to prevent this just make the systemd service run 2 mins after boot with 

[Timer]
OnBootSec=2min

Thanks a lot, I did not know that swapon accepts negative priorities whereas /etc/fstab doesn't.

I think more people find this option useful and it'd be good to add support for this directly in settings.

$ cat /etc/systemd/zram-generator.conf.d/librem5.conf
[zram0]
zram-fraction = 2
max-zram-size = none

Does this make sense for FLX1 as well ? Originally for Librem 5.
 https://forums.puri.sm/t/why-and-how-to-extend-zram-on-l5-a-revolution-for-librem-5-stability/24046/34?u=pirate_praveen