| #!/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. |
| # |
| # send SIGUSR1 to this process right after a new qemu process is started, or |
| # following its death, to retune ksm accordingly |
| # |
| # needs testing and ironing. contact danken@redhat.com if something breaks. |
| |
| if [ -f /etc/ksmtuned.conf ]; then |
| . /etc/ksmtuned.conf |
| fi |
| |
| debug() { |
| if [ -n "$DEBUG" ]; then |
| s="`/bin/date`: $*" |
| [ -n "$LOGFILE" ] && echo "$s" >> "$LOGFILE" || echo "$s" |
| fi |
| } |
| |
| |
| KSM_MONITOR_INTERVAL=${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` |
| debug total $total |
| |
| npages=0 |
| sleep=$[KSM_SLEEP_MSEC * 16 * 1024 * 1024 / total] |
| [ $sleep -le 10 ] && sleep=10 |
| debug sleep $sleep |
| thres=$[total * KSM_THRES_COEF / 100] |
| if [ $KSM_THRES_CONST -gt $thres ]; then |
| thres=$KSM_THRES_CONST |
| fi |
| debug 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-kvm} |
| ps -C "$progname" -o rsz | awk '{ sum += $1 }; END { print sum }' |
| } |
| |
| free_memory () { |
| awk '/^(MemFree|Buffers|Cached):/ {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` |
| debug committed $committed free $free |
| if [ $[committed + thres] -lt $total -a $free -gt $thres ]; then |
| KSMCTL stop |
| debug "$[committed + thres] < $total and free > $thres, stop ksm" |
| return 1 |
| fi |
| debug "$[committed + thres] > $total, start ksm" |
| if [ $free -lt $thres ]; then |
| npages=`increase_npages $KSM_NPAGES_BOOST` |
| debug "$free < $thres, boost" |
| else |
| npages=`increase_npages $KSM_NPAGES_DECAY` |
| debug "$free > $thres, decay" |
| fi |
| KSMCTL start $npages $sleep |
| debug "KSMCTL start $npages $sleep" |
| return 0 |
| } |
| |
| function nothing () { |
| : |
| } |
| |
| loop () { |
| trap nothing SIGUSR1 |
| while true |
| do |
| sleep $KSM_MONITOR_INTERVAL & |
| wait $! |
| adjust |
| done |
| } |
| |
| PIDFILE=${PIDFILE-/var/run/ksmtune.pid} |
| if touch "$PIDFILE"; then |
| loop & |
| echo $! > "$PIDFILE" |
| fi |