#!/bin/bash
#
# ksm          Kernel Samepage Merging
#
# Author:      Dan Kenigsberg <danken@redhat.com>
#
# Copyright 2009 Red Hat, Inc. and/or its affiliates.
# Released under the GPL
#
# chkconfig: 345 84 16
# description: The KSM init script starts and stops the ksm kernel thread.
# config: /etc/sysconfig/ksm
#
### BEGIN INIT INFO
# Provides: ksm
# Required-Start:
# Required-Stop:
# Should-Start:
# Default-Start: 3 4 5
# Short-Description: start and stop ksm
# Description: The KSM init script starts and stops the ksm kernel thread.
### END INIT INFO

. /etc/rc.d/init.d/functions

if [ -f /etc/sysconfig/ksm ]; then
    . /etc/sysconfig/ksm
fi

prog=ksm
RETVAL=0

# unless KSM_MAX_KERNEL_PAGES is set, let ksm munch up to half of total memory.
default_max_kernel_pages () {
    local total pagesize
    total=`awk '/^MemTotal:/ {print $2}' /proc/meminfo`
    pagesize=`getconf PAGESIZE`
    echo $[total * 1024 / pagesize / 2]
}

start() {
    echo -n $"Starting $prog: "
    if [ -f /sys/kernel/mm/ksm/max_kernel_pages ]; then
        KSM_MAX_KERNEL_PAGES=${KSM_MAX_KERNEL_PAGES:-`default_max_kernel_pages`}
        echo $KSM_MAX_KERNEL_PAGES > /sys/kernel/mm/ksm/max_kernel_pages
    fi
    echo 1 > /sys/kernel/mm/ksm/run
    RETVAL=$?
    [ $RETVAL = 0 ] && success $"$prog startup" || failure $"$prog startup"
    echo
}

stop() {
    echo -n $"Stopping $prog: "
    echo 0 > /sys/kernel/mm/ksm/run
    RETVAL=$?
    [ $RETVAL = 0 ] && success $"$prog shutdown" || failure $"$prog shutdown"
    echo
}

status() {
    if [ ! -f /sys/kernel/mm/ksm/run ] ; then
        echo $"$prog not supported"
        RETVAL=1
    else if [ "$(cat /sys/kernel/mm/ksm/run 2>/dev/null)" != "1" ]; then
        echo $"$prog is not running"
        RETVAL=1
    else
        echo $"$prog is running"
        RETVAL=0
    fi; fi
}

restart() {
    stop
    start
}

case "$1" in
  start)
	start
	;;
  stop)
	stop
	;;
  status)
        status
	;;
  restart)
	restart
	;;
  condrestart|try-restart)
	status >/dev/null 2>&1 || exit 0
	restart
        ;;
  force-reload)
	restart
	;;
  *)
	echo $"Usage: $prog {start|stop|restart|force-reload|condrestart|try-restart|status|help}"
	RETVAL=2
esac

exit $RETVAL