zramcfg-fallback

#!/bin/bash
#
# zramcfg - configure zram for semplice
# Copyright (C) 2013  Eugenio "g7" Paolantonio
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

set -e

error() {
	# This method displays an error
	echo "E: $@" >&2
	exit 1
}

# Parse arguments
while getopts "s" opt; do
	case "$opt" in
		s)
			STOP="y"
			;;
		\?)
			error "Invalid option: -$OPTARG"
			;;
	esac
done

[ ! -e /etc/default/zramcfg ] && error "Configuration file /etc/default/zramcfg missing!"

# Read configuration file
. /etc/default/zramcfg

# Parse NUM_DEVICES
if [ "$NUM_DEVICES" == "cpu" ]; then
	# Should look at the cpu to get the number of cores...
	NUM_DEVICES="`grep -c processor /proc/cpuinfo`"
	[ "$NUM_DEVICES" == "0" ] && NUM_DEVICES="1"
fi

# Parse SIZE
if [[ "$SIZE" == *"%"* ]]; then
	# It's a percentage
	__memory="`grep MemTotal /proc/meminfo | awk '{ print $2 }'`"
	# 8000 : 100 = x : 25
	SIZE=$(($__memory * ${SIZE//"%"/} / 100 / 1024))
fi
# Now divide it equally...
SIZE=$(($SIZE / $NUM_DEVICES ))

# Modprobe
[ -z "$STOP" ] && modprobe zram num_devices=$NUM_DEVICES

for num in $(seq 0 $(($NUM_DEVICES - 1))); do
	if [ -z "$STOP" ]; then
		# Set disksize
		echo $((${SIZE}*1024*1024)) > /sys/block/zram${num}/disksize
		
		# Make swap
		/sbin/mkswap /dev/zram${num}
		
		# Mount
		/sbin/swapon /dev/zram${num} -p 32767
	else
		# Shutdown swap
		/sbin/swapoff /dev/zram${num}
		
		# Reset
		echo 1 > /sys/block/zram${num}/reset

	fi
done

# Modprobe -r if stop
[ -n "$STOP" ] && modprobe -r zram