From 4a1e6c8cb3959e2cda0d405a1bf6b0368e58cd17 Mon Sep 17 00:00:00 2001
From: Adrien <adrien@reslinger.net>
Date: Mon, 8 Oct 2018 08:36:03 +0200
Subject: [PATCH] Externalize zram role

---
 files/etc/systemd/system/zram-config.service | 14 ++++
 files/usr/local/sbin/zram-swap.sh            | 77 ++++++++++++++++++++
 tasks/main.yml                               | 13 ++++
 3 files changed, 104 insertions(+)
 create mode 100644 files/etc/systemd/system/zram-config.service
 create mode 100755 files/usr/local/sbin/zram-swap.sh
 create mode 100644 tasks/main.yml

diff --git a/files/etc/systemd/system/zram-config.service b/files/etc/systemd/system/zram-config.service
new file mode 100644
index 0000000..a804ce3
--- /dev/null
+++ b/files/etc/systemd/system/zram-config.service
@@ -0,0 +1,14 @@
+[Unit]
+Description=ZRAM Swap
+#After=syslog.target NetworkManager.service
+
+[Service]
+ExecStart=/usr/local/sbin/zram-swap.sh start
+ExecStop=/usr/local/sbin/zram-swap.sh stop
+#KillMode=process
+#Restart=off
+Type=oneshot
+RemainAfterExit=yes
+
+[Install]
+WantedBy=multi-user.target
diff --git a/files/usr/local/sbin/zram-swap.sh b/files/usr/local/sbin/zram-swap.sh
new file mode 100755
index 0000000..f4cfc9f
--- /dev/null
+++ b/files/usr/local/sbin/zram-swap.sh
@@ -0,0 +1,77 @@
+#!/bin/bash
+#
+# zram-config      Start zram-config
+#
+# chkconfig: 2345 08 92
+# description:  Starts, stops and saves zram-config
+#
+#
+### BEGIN INIT INFO
+# Provides: zram-config
+# Required-Start:
+# Required-Stop:
+# Default-Start: 2 3 4 5
+# Default-Stop: 0 1 6
+# Short-Description: start and stop zram-config
+# Description: Start, stop and save zram-config
+### END INIT INFO
+
+# http://askubuntu.com/questions/130374/ramdisk-compressed-writeable-no-swap
+# https://kernel.org/doc/Documentation/blockdev/zram.txt
+
+#NRDEVICES=$[$(grep ^physical\ id /proc/cpuinfo | sort -u | wc -l)*$(grep ^core\ id /proc/cpuinfo | sort -u | wc -l)]
+#if [ $NRDEVICES -eq 0 ]; then
+#	NRDEVICES=$(grep -c '^processor\s*:' /proc/cpuinfo)
+#fi
+#NRDEVICES=1
+case "$1" in
+	start)
+		if [ $(grep -c /dev/zram /proc/swaps) -gt 1 ]; then
+			echo "Already running" >&2
+			exit 2
+		fi
+		if [ $(lsmod | grep -c zram) -eq 0 ]; then
+			modprobe zram
+			ZRAMID=0
+		else
+			ZRAMID=$(cat /sys/class/zram-control/hot_add)
+		fi
+		MEM=$(free -k | grep -e "^Mem:" | awk '{printf("%d\n",$2/1.2)}')
+		# echo 1 > /sys/block/zram${ZRAMID}/reset
+		if [ -e /sys/block/zram${ZRAMID}/comp_algorithm ]; then
+			if [ $(grep -c lz4 /sys/block/zram${ZRAMID}/comp_algorithm) -eq 1 ]; then
+				echo lz4 > /sys/block/zram${ZRAMID}/comp_algorithm 
+			fi
+		fi
+		if [ -e /sys/block/zram${ZRAMID}/mem_limit ]; then
+			echo $[${MEM}*2]k > /sys/block/zram${ZRAMID}/disksize
+			echo ${MEM}k > /sys/block/zram${ZRAMID}/mem_limit
+		else
+			echo ${MEM}k > /sys/block/zram${ZRAMID}/disksize
+		fi
+		mkswap /dev/zram${ZRAMID}
+		swapon -p 10 /dev/zram${ZRAMID}
+		;;
+	stop)
+		# Suppression zram
+		# echo X > /sys/class/zram-control/hot_remove ou X=0 pour zram0
+		for ZRAMID in $(grep /dev/zram /proc/swaps | awk '{print $1}' | cut -c10-); do
+			swapoff /dev/zram${ZRAMID}
+			echo 1 > /sys/block/zram${ZRAMID}/reset
+			echo ${ZRAMID} > /sys/class/zram-control/hot_remove
+		done
+		modprobe -r zram
+		;;
+esac
+#mke2fs -q -m 0 -b 4096 -O sparse_super -L zram /dev/zram0
+#mount -o relatime,noexec,nosuid /dev/zram0 /mnt/zram
+#chmod 1777 /mnt/zram/
+
+# cat /sys/block/zram0/mem_used_total
+
+
+# https://www.google.fr/search?q=sysem+to+ram+pivot_root&ie=utf-8&oe=utf-8&rls=org.mozilla:fr:unofficial&client=seamonkey-a&gws_rd=cr&ei=ThHLVs3WA4H9acbUtNAH#q=system+to+ram+pivot_root
+#http://dreamlayers.blogspot.fr/2012/10/running-linux-from-ram.html
+#http://unix.stackexchange.com/questions/126217/when-would-you-use-pivot-root-over-switch-root
+#https://wiki.gentoo.org/wiki/Zram
+
diff --git a/tasks/main.yml b/tasks/main.yml
new file mode 100644
index 0000000..95b6493
--- /dev/null
+++ b/tasks/main.yml
@@ -0,0 +1,13 @@
+---
+- name: Install script zram-swap.sh
+  copy: src=files/usr/local/sbin/zram-swap.sh dest=/usr/local/sbin/zram-swap.sh owner=root group=root mode=0755
+- name: Install service zram-config.service
+  copy: src=files/etc/systemd/system/zram-config.service dest=/etc/systemd/system/zram-config.service owner=root group=root mode=0644
+  when: ansible_service_mgr == "systemd"
+- name: Install zram-config link service in init.d 
+  file: src=/usr/local/sbin/zram-swap.sh dest=/etc/init.d/zram-config owner=root group=root state=link
+  when: ansible_service_mgr != "systemd"
+- name: start zram-config service
+  service: name=zram-config enabled=yes state=started
+#  when: ansible_service_mgr == "systemd"
+