feat: auto-configure zram at boot with optimal settings

.gitignore

@@ -1,3 +1,16 @@
+debian/
+!debian/*.install
+!debian/*.links
+!debian/*.postinst
+!debian/*.postrm
+!debian/*.prerm
+!debian/*.service
+!debian/changelog
+!debian/compat
+!debian/copyright
+!debian/rules
+!debian/source/
+
 etc/pop-os/issue
 etc/pop-os/issue.net
 etc/pop-os/lsb-release

debian/control

@@ -19,6 +19,13 @@ Depends: ${misc:Depends},
          python3-repolib (>> 1.3.9),
          ubuntu-minimal,
          ubuntu-standard,
+Recommends: pop-default-settings-zram
 Conflicts: pipewire-media-session
 Description: default settings for Pop OS
  This package contains the default settings used by Pop.
+
+Package: pop-default-settings-zram
+Architecture: all
+Depends: ${misc:Depends}, pop-default-settings, util-linux
+Description: default settings for ZRAM on Pop OS
+ This package contains the default zram settings used by Pop.

debian/pop-default-settings-zram.install

@@ -0,0 +1,2 @@
+etc/default/pop-zram
+usr/bin/pop-zram-config

debian/pop-default-settings-zram.service

@@ -0,0 +1,9 @@
+[Unit]
+Description=Auto-configure and enable zram on Pop
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/pop-zram-config
+
+[Install]
+WantedBy=multi-user.target

debian/pop-default-settings.install

@@ -1,3 +1,47 @@
-etc
-lib
-usr
+etc/apt/apt.conf.d/76pop-default-settings
+etc/apt/preferences.d/pop-default-settings
+etc/chrony/conf.d/10-system76-nts.conf
+etc/chrony/sources.d/system76-nts.sources
+etc/modules-load.d/pop-modules.conf
+etc/pop-os/flatpak/flathub.flatpakrepo
+etc/pop-os/gdm3/custom.conf
+etc/pop-os/issue
+etc/pop-os/issue.net
+etc/pop-os/legal
+etc/pop-os/lsb-release
+etc/pop-os/os-release
+etc/pop-os/update-motd.d/10-help-text
+etc/pop-os/update-motd.d/50-motd-news
+etc/profile.d/pop-im-ibus.sh
+etc/sysctl.d/10-pop-default-settings.conf
+etc/update-manager/release-upgrades.d/pop-default-settings.cfg
+etc/xdg/autostart/pop-app-folders.desktop
+etc/xdg/autostart/pop-flatpak-repos.desktop
+lib/systemd/system-sleep/pop-default-settings_bluetooth-suspend
+lib/udev/rules.d/60-block-pop.rules
+usr/bin/pop-app-folders
+usr/bin/pop-cosmic-favorites
+usr/bin/pop-flatpak-repos
+usr/lib/firefox/browser/defaults/preferences/pop-default-settings.js
+usr/lib/firefox/defaults/pref/pop-default-settings.js
+usr/lib/systemd/journald.conf.d/pop.conf
+usr/share/applications/pop-mimeapps.list
+usr/share/gtksourceview-3.0/styles/pop-dark.xml
+usr/share/gtksourceview-3.0/styles/pop-light.xml
+usr/share/gtksourceview-4/styles/pop-dark.xml
+usr/share/gtksourceview-4/styles/pop-light.xml
+usr/share/icons/pop-os-branding/256x256/apps/ubuntu-logo-icon.png
+usr/share/icons/pop-os-branding/index.theme
+usr/share/icons/pop-os-branding/pop_icon.svg
+usr/share/icons/pop-os-branding/round-logos/16/distributor-logo.svg
+usr/share/icons/pop-os-branding/round-logos/16/ubuntu-logo-icon.svg
+usr/share/icons/pop-os-branding/round-logos/22/distributor-logo.svg
+usr/share/icons/pop-os-branding/round-logos/24/distributor-logo.svg
+usr/share/icons/pop-os-branding/round-logos/32/distributor-logo.svg
+usr/share/icons/pop-os-branding/round-logos/48/distributor-logo.svg
+usr/share/icons/pop-os-branding/round-logos/64/distributor-logo.svg
+usr/share/pipewire/media-session.d/with-alsa
+usr/share/pipewire/media-session.d/with-jack
+usr/share/pipewire/media-session.d/with-pulseaudio
+usr/share/pixmaps/faces/pop-robot.png
+usr/share/X11/xorg.conf.d/10-pop-dpms.conf

debian/rules

@@ -1,8 +1,4 @@
 #!/usr/bin/make -f
 
-override_dh_installdeb:
-	dh_installdeb
-	cp debian/conffiles debian/pop-default-settings/DEBIAN/conffiles
-
 %:
 	dh $@

etc/default/pop-zram

@@ -0,0 +1,8 @@
+# Default to 16384M as max zram block size.
+MAX_SIZE=16384
+# Amount of memory to use for zram, from 1 to 200.
+PORTION=100
+# Default to compress with zstd, which has an average compression ratio of 3.37.
+ALGO=zstd
+# Higher values encourage the kernel to be more eager to move pages to swap.
+SWAPPINESS=180

etc/sysctl.d/10-pop-default-settings.conf

@@ -1,3 +1,5 @@
 vm.swappiness = 10
+vm.watermark_boost_factor=0
+vm.watermark_scale_factor = 125
 vm.dirty_bytes = 268435456
 vm.dirty_background_bytes = 134217728

usr/bin/pop-zram-config

@@ -0,0 +1,67 @@
+#!/bin/bash
+# Copyright 2022 System76 <info@system76.com>
+# SPDX-License-Identifier: GPL-3.0-only
+
+# If a zram device already exists, ignore
+test -b /dev/zram0 && exit 0
+
+ENV_CONF='/etc/pop-zram'
+
+# Load user-defined variabls if a config exists
+if test -f ${ENV_CONF}; then
+    export $(grep -v '^#' ${ENV_CONF} | xargs)
+fi
+
+# Default to compress with zstd, which has an average compression ratio of 3.37.
+test -n "${ALGO}" || ALGO=zstd
+
+# Max amount of uncompressed RAM that should be compressed.
+test -n "${MAX_SIZE}" || MAX_SIZE=16384
+
+# Higher values encourage the kernel to be more eager to move pages to swap.
+test -n "${SWAPPINESS}" || SWAPPINESS=180
+
+# Amount of memory to use for zram, from 1 to 200
+test -n "${PORTION}" || PORTION=100
+
+if ((PORTION > 200)); then
+    PORTION=200
+elif ((PORTION < 1)); then
+    PORTION=1
+fi
+
+# Number of consecutive pages to read in advance. Higher values increase compression
+# for zram devices, but at the cost of significantly reduced IOPS and higher latency.
+# It is highly recommended to use 0 for zstd; and 1 for speedier algorithms.
+test -n "${PAGE_CLUSTERS}" || PAGE_CLUSTERS=$(test zstd = ${ALGO} && echo 0 || echo 1)
+
+# Total amount of memory accessible to the OS.
+TOTAL=$(awk -v p=${PORTION} '/MemTotal/ {printf "%.0f", p * $2 / 102400}' /proc/meminfo)
+
+# Ensure that the size is not greater than the max size.
+SIZE=$(((TOTAL > MAX_SIZE)) && echo ${MAX_SIZE} || echo ${TOTAL})
+
+# Load the zram module.
+modprobe zram num_devices=1
+udevadm settle -t 1
+
+# Create it with our desired size and compression algorithm
+zramctl --size "${SIZE}M" --algorithm "${ALGO}" /dev/zram0
+
+# Format it as a swap partition
+mkswap /dev/zram0
+udevadm settle -t 1
+
+# Activate the zram device with a priority of 1000.
+# This device should have a higher priority than disk-based swap.
+swapon -p 1000 /dev/zram0
+
+# Apply optimal sysctl values for the zram environment.
+sysctl -w "vm.page-cluster=${PAGE_CLUSTERS}" "vm.swappiness=${SWAPPINESS}"
+
+# Ensure at least 1% of total memory is free to avoid system freeze.
+MINIMUM=$(awk '/MemTotal/ {printf "%.0f", $2 * 0.01}' /proc/meminfo)
+CURRENT=$(sysctl vm.min_free_kbytes | awk '{print $3}')
+if ((MINIMUM > CURRENT)); then
+    sysctl -w "vm.min_free_kbytes=${MINIMUM}"
+fi