#!/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() {
    gprintf "Starting %s: " "$prog"
    KSM_MAX_KERNEL_PAGES=${KSM_MAX_KERNEL_PAGES:-`default_max_kernel_pages`}
    echo $KSM_MAX_KERNEL_PAGES > /sys/kernel/mm/ksm/max_kernel_pages
    echo 1 > /sys/kernel/mm/ksm/run
    RETVAL=$?
    [ $RETVAL = 0 ] && success $"%s startup" "$prog" || failure $"%s startup" "$prog"
    echo
    return $RETVAL
}

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

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

case "$1" in
  start)
	start
	;;
  stop)
	stop
	;;
  status)
        status
	;;
  restart)
	stop
	start
	;;
  condrestart)
        ;;
  *)
	gprintf "Usage: %s {start|stop|restart|condrestart|status|help}\n" "$prog"
	RETVAL=3
esac

exit $RETVAL
