140 lines
3.4 KiB
Bash
140 lines
3.4 KiB
Bash
#!/bin/bash
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#
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# Copyright 2009 Red Hat, Inc. and/or its affiliates.
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# Released under the GPL
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#
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# Author: Dan Kenigsberg <danken@redhat.com>
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#
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# ksmtuned - a simple script that controls whether (and with what vigor) ksm
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# should search for duplicated pages.
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#
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# starts ksm when memory commited to qemu processes exceeds a threshold, and
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# make ksm work harder and harder untill memory load falls below that
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# threshold.
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#
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# send SIGUSR1 to this process right after a new qemu process is started, or
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# following its death, to retune ksm accordingly
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#
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# needs testing and ironing. contact danken@redhat.com if something breaks.
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if [ -f /etc/ksmtuned.conf ]; then
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. /etc/ksmtuned.conf
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fi
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debug() {
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if [ -n "$DEBUG" ]; then
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s="`/bin/date`: $*"
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[ -n "$LOGFILE" ] && echo "$s" >> "$LOGFILE" || echo "$s"
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fi
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}
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KSM_MONITOR_INTERVAL=${KSM_MONITOR_INTERVAL:-60}
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KSM_NPAGES_BOOST=${KSM_NPAGES_BOOST:-300}
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KSM_NPAGES_DECAY=${KSM_NPAGES_DECAY:--50}
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KSM_NPAGES_MIN=${KSM_NPAGES_MIN:-64}
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KSM_NPAGES_MAX=${KSM_NPAGES_MAX:-1250}
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# millisecond sleep between ksm scans for 16Gb server. Smaller servers sleep
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# more, bigger sleep less.
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KSM_SLEEP_MSEC=${KSM_SLEEP_MSEC:-10}
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KSM_THRES_COEF=${KSM_THRES_COEF:-20}
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KSM_THRES_CONST=${KSM_THRES_CONST:-2048}
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total=`awk '/^MemTotal:/ {print $2}' /proc/meminfo`
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debug total $total
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npages=0
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sleep=$[KSM_SLEEP_MSEC * 16 * 1024 * 1024 / total]
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[ $sleep -le 10 ] && sleep=10
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debug sleep $sleep
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thres=$[total * KSM_THRES_COEF / 100]
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if [ $KSM_THRES_CONST -gt $thres ]; then
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thres=$KSM_THRES_CONST
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fi
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debug thres $thres
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KSMCTL () {
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case x$1 in
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xstop)
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echo 0 > /sys/kernel/mm/ksm/run
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;;
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xstart)
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echo $2 > /sys/kernel/mm/ksm/pages_to_scan
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echo $3 > /sys/kernel/mm/ksm/sleep_millisecs
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echo 1 > /sys/kernel/mm/ksm/run
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;;
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esac
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}
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committed_memory () {
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# calculate how much memory is committed to running qemu processes
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local pidlist
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pidlist=$(pgrep -d ' ' -- '^qemu(-(kvm|system-.+)|:.{1,11})$')
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if [ -n "$pidlist" ]; then
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ps -p "$pidlist" -o rsz=
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fi | awk '{ sum += $1 }; END { print 0+sum }'
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}
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free_memory () {
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awk '/^(MemFree|Buffers|Cached):/ {free += $2}; END {print free}' \
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/proc/meminfo
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}
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increase_npages() {
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local delta
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delta=${1:-0}
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npages=$[npages + delta]
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if [ $npages -lt $KSM_NPAGES_MIN ]; then
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npages=$KSM_NPAGES_MIN
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elif [ $npages -gt $KSM_NPAGES_MAX ]; then
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npages=$KSM_NPAGES_MAX
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fi
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echo $npages
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}
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adjust () {
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local free committed
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free=`free_memory`
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committed=`committed_memory`
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debug committed $committed free $free
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if [ $[committed + thres] -lt $total -a $free -gt $thres ]; then
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KSMCTL stop
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debug "$[committed + thres] < $total and free > $thres, stop ksm"
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return 1
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fi
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debug "$[committed + thres] > $total, start ksm"
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if [ $free -lt $thres ]; then
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npages=`increase_npages $KSM_NPAGES_BOOST`
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debug "$free < $thres, boost"
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else
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npages=`increase_npages $KSM_NPAGES_DECAY`
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debug "$free > $thres, decay"
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fi
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KSMCTL start $npages $sleep
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debug "KSMCTL start $npages $sleep"
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return 0
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}
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function nothing () {
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:
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}
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loop () {
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trap nothing SIGUSR1
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while true
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do
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sleep $KSM_MONITOR_INTERVAL &
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wait $!
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adjust
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done
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}
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PIDFILE=${PIDFILE-/var/run/ksmtune.pid}
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if touch "$PIDFILE"; then
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loop &
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echo $! > "$PIDFILE"
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fi
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