qemu/ksmtuned
Mark McLoughlin cd8d5cb64c - Add ksmtuned, also from Dan Kenigsberg
- Use %_initddir macro
2009-09-16 17:31:15 +00:00

121 lines
3.2 KiB
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#!/bin/bash
#
# Copyright 2009 Red Hat, Inc. and/or its affiliates.
# Released under the GPL
#
# Author: Dan Kenigsberg <danken@redhat.com>
#
# ksmtuned - a simple script that controls whether (and with what vigor) ksm
# should search for duplicated pages.
#
# starts ksm when memory commited to qemu processes exceeds a threshold, and
# make ksm work harder and harder untill memory load falls below that
# threshold.
#
# needs testing and ironing. contact danken@redhat.com if something breaks.
if [ -f /etc/ksmtuned.conf ]; then
. /etc/ksmtuned.conf
fi
KSM_MONITOR_INTERVAL=${KSM_MONITOR_INTERVAL:-60}
KSM_NPAGES_BOOST=${KSM_NPAGES_BOOST:-300}
KSM_NPAGES_DECAY=${KSM_NPAGES_DECAY:--50}
KSM_NPAGES_MIN=${KSM_NPAGES_MIN:-64}
KSM_NPAGES_MAX=${KSM_NPAGES_MAX:-1250}
# millisecond sleep between ksm scans for 16Gb server. Smaller servers sleep
# more, bigger sleep less.
KSM_SLEEP_MSEC=${KSM_SLEEP_MSEC:-10}
KSM_THRES_COEF=${KSM_THRES_COEF:-20}
KSM_THRES_CONST=${KSM_THRES_CONST:-2048}
total=`awk '/^MemTotal:/ {print $2}' /proc/meminfo`
[ -n "$DEBUG" ] && echo total $total
npages=0
sleep=$[KSM_SLEEP_MSEC * 16 * 1024 * 1024 / total]
[ $sleep -le 10 ] && sleep=10
[ -n "$DEBUG" ] && echo sleep $sleep
thres=$[total * KSM_THRES_COEF / 100]
if [ $KSM_THRES_CONST -gt $thres ]; then
thres=$KSM_THRES_CONST
fi
[ -n "$DEBUG" ] && echo thres $thres
KSMCTL () {
case x$1 in
xstop)
echo 0 > /sys/kernel/mm/ksm/run
;;
xstart)
echo $2 > /sys/kernel/mm/ksm/pages_to_scan
echo $3 > /sys/kernel/mm/ksm/sleep_millisecs
echo 1 > /sys/kernel/mm/ksm/run
;;
esac
}
committed_memory () {
# calculate how much memory is committed to running qemu processes
local progname
progname=${1:-qemu}
ps -o vsz `pgrep $progname` | awk '{ sum += $1 }; END { print sum }'
}
free_memory () {
awk '/^(MemFree|Buffers|MemCached):/ {free += $2}; END {print free}' \
/proc/meminfo
}
increase_npages() {
local delta
delta=${1:-0}
npages=$[npages + delta]
if [ $npages -lt $KSM_NPAGES_MIN ]; then
npages=$KSM_NPAGES_MIN
elif [ $npages -gt $KSM_NPAGES_MAX ]; then
npages=$KSM_NPAGES_MAX
fi
echo $npages
}
adjust () {
local free committed
free=`free_memory`
committed=`committed_memory`
[ -n "$DEBUG" ] && echo committed $committed free $free
if [ $[committed + thres] -lt $total -a $free -gt $thres ]; then
KSMCTL stop
[ -n "$DEBUG" ] && echo "$[committed + thres] < $total and free > $thres, stop ksm"
return 1
fi
[ -n "$DEBUG" ] && echo "$[committed + thres] > $total, start ksm"
if [ $free -lt $thres ]; then
npages=`increase_npages $KSM_NPAGES_BOOST`
[ -n "$DEBUG" ] && echo "$free < $thres, boost"
else
npages=`increase_npages $KSM_NPAGES_DECAY`
[ -n "$DEBUG" ] && echo "$free > $thres, decay"
fi
KSMCTL start $npages $sleep
[ -n "$DEBUG" ] && echo "KSMCTL start $npages $sleep"
return 0
}
loop () {
while true
do
sleep $KSM_MONITOR_INTERVAL
adjust
done
}
PIDFILE=${PIDFILE-/var/run/ksmtune.pid}
if touch "$PIDFILE"; then
loop &
echo $! > "$PIDFILE"
fi