tangetools/zram-init/zram

#!/bin/bash
### BEGIN INIT INFO
# Provides: zram
# Required-Start:
# Required-Stop:
# Default-Start: 2 3 4 5
# Default-Stop: 0 1 6
# Short-Description: Increased Performance In Linux With zRam (Virtual Swap Compressed in RAM)
# Description: Adapted from systemd scripts at https://github.com/mystilleef/FedoraZram
### END INIT INFO
# Author: tradetaxfree http://crunchbanglinux.org/forums/topic/15344/zram-a-good-idea/

start() {
    # get the number of CPUs
    num_cpus=$(grep -c processor /proc/cpuinfo)
    # if something goes wrong, assume we have 1
    [ "$num_cpus" != 0 ] || num_cpus=1

    # set decremented number of CPUs
    decr_num_cpus=$((num_cpus - 1))

    # get the amount of memory in the machine
    mem_total_kb=$(grep MemTotal /proc/meminfo | grep -E --only-matching '[[:digit:]]+')
    mem_total=$((mem_total_kb * 1024))

    # load dependency modules
    modprobe zram zram_num_devices=$num_cpus || modprobe zram num_devices=$num_cpus || exit 1

    # initialize the devices
    for i in $(seq 0 $decr_num_cpus); do
    echo $((mem_total / num_cpus)) > /sys/block/zram$i/disksize
    done

    # Creating swap filesystems
    for i in $(seq 0 $decr_num_cpus); do
    mkswap /dev/zram$i
    done

    # Switch the swaps on
    for i in $(seq 0 $decr_num_cpus); do
    swapon -p 100 /dev/zram$i
    done
}

stop() {
    # get the number of CPUs
    num_cpus=$(grep -c processor /proc/cpuinfo)

    # set decremented number of CPUs
    decr_num_cpus=$((num_cpus - 1))

    # Switching off swap
    for i in $(seq 0 $decr_num_cpus); do
    if [ "$(grep /dev/zram$i /proc/swaps)" != "" ]; then
    swapoff /dev/zram$i
    sleep 0.1
    fi
    done

    sleep 0.1
    modprobe -r zram
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    restart)
        stop
        sleep 3
        start
        ;;
    *)
        echo "Usage: $0 {start|stop|restart}"
        RETVAL=1
esac
exit $RETVAL