# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1245147448 -3600
# Node ID 8373971089a7342bbd76e33124887e977095ef09
# Parent 7f9286d21706d6cf06441adc285188fc27ae780d
tools/xenballoond: add tmem capability to directed/self-ballooning
and monitor tool
This patch adds tmem support to the largely unknown/unused
xenballoond scripts that implement both self-ballooning and
a foundation for directed-ballooning. Tmem and automated
ballooning are highly complementary in that, when ballooning
is over-aggressive, paging and swapping can increase noticably.
Precache preserves evicted pages that may be needed again soon
(thus eliminating disk reads) and preswap provides memory-based
swapping that occurs if ballooning is insufficiently responsive
to a sudden increase in activity and memory demand (thus
eliminating disk writes and reads).
There are two changes in this patch:
1) The xenballoond service is a convenient place to implement
userland "preswap shrinking".**
2) The xenballoon-monitor script is a convenient place to
report (and view with "watch -d") the frequent memory
rebalancing that results from tmem usage on a busy system.
Note that for best results (and for the monitor script to
work), the xenstore-* tools should be installed on each guest.
(** In a disk-based swap device, stale pages are often left
on-disk even after they are no longer needed or valid; they
are simply overwritten if/when the disk blocks are needed
again, which may be a very long time. Preswap behaves
much like a disk, but uses precious pages of memory that
count against a guest's memory allocation; thus stale
pages are very undesirable. Preswap shrinking periodically
attempts to remove stale pages from preswap by using a
sysfs interface created by the linux-side tmem patch.)
Signed-off-by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
---
tools/xenballoon/xenballoon-monitor | 48 ++++++++++++++-------
tools/xenballoon/xenballoon.conf | 45 ++++++++++++++++++++
tools/xenballoon/xenballoond | 79 ++++++++++++++++++++++++++++++++++--
tools/xenballoon/xenballoond.init | 2
4 files changed, 154 insertions(+), 20 deletions(-)
diff -r 7f9286d21706 -r 8373971089a7 tools/xenballoon/xenballoon-monitor
--- a/tools/xenballoon/xenballoon-monitor Tue Jun 16 11:15:48 2009 +0100
+++ b/tools/xenballoon/xenballoon-monitor Tue Jun 16 11:17:28 2009 +0100
@@ -2,6 +2,7 @@
#
# xenballoon-monitor - monitor certain stats from xenballoond
# (run in dom0 with "watch -d xenballoon-monitor" for xentop-like output)
+# updated 090610 to include tmem stats
#
# Copyright (C) 2009 Oracle Corporation and/or its affiliates.
# All rights reserved
@@ -9,10 +10,12 @@
#
# Hint: Use "xm sched-credit -d 0 -w 2000" to watch on heavily loaded machines
#
-echo "id mem-kb tgt-kb commit swapin swapout pgin pgout
active(sec)"
+TMEMTMP=$(/bin/mktemp -q /tmp/xenballoon-monitor.XXXXXX)
+echo "id mem-kb tgt-kb commit swapin swapout pgin pgout preswap
precache"
for i in `xenstore-list /local/domain`; do
if [ "$i" -ne 0 ]; then
- tot=0; tgt=0; sin=0; sout=0; pgin=0; pgout=0; cmt=0; up=0; idle=0; act=0;
+ tot=0; tgt=0; sin=0; sout=0; pgin=0; pgout=0; cmt=0; up=0; idle=0;
+ act=0; preswap=0; precache=0
if xenstore-exists /local/domain/$i/memory/meminfo; then
tot=`xenstore-read /local/domain/$i/memory/meminfo | grep MemTotal \
| sed 's/[^1-9]*\([1-9][0-9]*\).*/\1/'`
@@ -23,21 +26,34 @@ for i in `xenstore-list /local/domain`;
tgt=`xenstore-read /local/domain/$i/memory/selftarget`
fi
if xenstore-exists /local/domain/$i/memory/vmstat; then
- sin=`xenstore-read /local/domain/$i/memory/vmstat | grep pswpin \
- | cut -d" " -f2`
- sout=`xenstore-read /local/domain/$i/memory/vmstat | grep pswpout \
- | cut -d" " -f2`
- pgin=`xenstore-read /local/domain/$i/memory/vmstat | grep pgpgin \
- | cut -d" " -f2`
- pgout=`xenstore-read /local/domain/$i/memory/vmstat | grep pgout \
- | cut -d" " -f2`
+ sin=$(xenstore-read /local/domain/$i/memory/vmstat | tr '\\\n' '\n' \
+ | grep pswpin | cut -d" " -f2)
+ sout=$(xenstore-read /local/domain/$i/memory/vmstat | tr '\\\n' '\n' \
+ | grep pswpout | cut -d" " -f2)
+ pgin=$(xenstore-read /local/domain/$i/memory/vmstat | tr '\\\n' '\n' \
+ | grep pgpgin | cut -d" " -f2)
+ pgout=$(xenstore-read /local/domain/$i/memory/vmstat | tr '\\\n' '\n' \
+ | grep pgout | cut -d" " -f2)
fi
- if xenstore-exists /local/domain/$i/memory/uptime; then
- up=`xenstore-read /local/domain/$i/memory/uptime | cut -d" " -f1`
- idle=`xenstore-read /local/domain/$i/memory/uptime | cut -d" " -f2`
- act=`echo $up - $idle | bc -iq`
+ xm tmem-list --all --long > $TMEMTMP
+ precache=`grep "C=CI:$i" $TMEMTMP | sed 's/C=CI.*Ec:\([0-9][0-9]*\).*/\1/'`
+ if xenstore-exists /local/domain/$i/memory/preswap; then
+ preswap=`xenstore-read /local/domain/$i/memory/preswap`
+ printf "%2d %8d%8d%8d%7d%8d%9d%9d%9d%9d\n" $i $tot $tgt $cmt $sin $sout
$pgin $pgout $preswap $precache
+ else
+ printf "%2d %8d%8d%8d%9d%9d%10d%10d\n" $i $tot $tgt $cmt $sin $sout $pgin
$pgout
fi
- printf "%2d %8d%8d%8d%9d%9d%10d%10d%10.2f\n" $i $tot $tgt $cmt $sin $sout
$pgin $pgout $act
fi
done
-echo Free memory: `xm info | grep free | sed 's/[^1-9]*\([1-9][0-9]*\).*/\1/'`
MB
+echo -n Free memory: `xm info | grep free | sed
's/[^1-9]*\([1-9][0-9]*\).*/\1/'` MiB " "
+tmem_free_pages=`grep "G=" $TMEMTMP | sed 's/G=.*Ta:\([0-9][0-9]*\).*/\1/'`
+if [ ! -z "$tmem_free_pages" ]; then
+ let "tmem_free_mb=$tmem_free_pages/256"
+ echo -n Idle tmem: $tmem_free_mb MiB " "
+fi
+tmem_eph_pages=`grep "G=" $TMEMTMP | sed 's/G=.*Ec:\([0-9][0-9]*\).*/\1/'`
+if [ ! -z "$tmem_eph_pages" ]; then
+ let "tmem_eph_mb=$tmem_eph_pages/256"
+ echo -n Ephemeral tmem: $tmem_eph_mb MiB
+fi
+echo ""
diff -r 7f9286d21706 -r 8373971089a7 tools/xenballoon/xenballoon.conf
--- a/tools/xenballoon/xenballoon.conf Tue Jun 16 11:15:48 2009 +0100
+++ b/tools/xenballoon/xenballoon.conf Tue Jun 16 11:17:28 2009 +0100
@@ -89,3 +89,48 @@ XENBALLOON_SEND_VMSTAT=1
# If xenbus is enabled, whether selfballooning or directed ballooning,
# place the result of 'cat /proc/uptime" on xenbus at memory/uptime
XENBALLOON_SEND_UPTIME=1
+
+## Type: boolean
+## Default: false
+#
+# If tmem is running, pages swapped to a swap disk may instead go
+# into preswap. These pages may become stale (i.e. no longer need
+# to be saved because, e.g., the process owning them has gone away)
+# and stale pages use precious precious domain-allocated memory.
+# Periodically try to reduce preswap to squeeze out stale pages
+XENBALLOON_PRESWAP_SHRINK=false
+
+## Type: string
+## Default: "/proc/sys/vm/preswap"
+## (change to /sys/proc/vm/preswap in later kernels)
+#
+# If tmem and preswap are running, reading this file gives the number of
+# pages currently in preswap. Writing it with N invokes the preswap_shrink
+# routine to reduce preswap to N pages.
+XENBALLOON_PRESWAP_SYSFILE=/proc/sys/vm/preswap
+
+## Type: integer (must be > 0)
+## Default: 20
+#
+# If tmem and preswap are running, attempts to reduce number of pages
+# currently in preswap. For a value of n, 1/n of the pages will
+# be attempted to be shrunk.
+# If xenbus is enabled, may be overridden by {memory/preswaphysteresis}
+XENBALLOON_PRESWAP_HYSTERESIS=20
+
+## Type: integer (must be > 0)
+## Default: 10
+#
+# Number of ballooning intervals where preswap size remains at N pages
+# before preswap shrinking is attempted. Also if shrinking fails to
+# shrink to the target, counter resets to this value.
+# If xenbus is enabled, may be overridden by {memory/preswapinertia}
+XENBALLOON_PRESWAP_INERTIA=10
+
+## Type: integer (0 or 1)
+## Default: 1
+#
+# If xenbus is enabled, whether selfballooning or directed ballooning,
+# place the size of preswap (in pages) on xenbus at memory/preswap
+XENBALLOON_SEND_PRESWAP=1
+
diff -r 7f9286d21706 -r 8373971089a7 tools/xenballoon/xenballoond
--- a/tools/xenballoon/xenballoond Tue Jun 16 11:15:48 2009 +0100
+++ b/tools/xenballoon/xenballoond Tue Jun 16 11:17:28 2009 +0100
@@ -5,9 +5,10 @@
# Written by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
#
# xenballoond - In-guest engine for Xen memory ballooning
-# Version: 080630
-#
-# Two "policies" are implemented:
+# Original version: 080630
+# Updated 0906XX: add tmem preswap auto-shrinking
+#
+# Two self-ballooning "policies" are implemented:
# - Selfballooning: Adjust memory periodically, with no (or little) input
# from domain0. Target memory is determined solely by the
# Committed_AS line in /proc/meminfo, but parameters may adjust
@@ -149,6 +150,75 @@ send_memory_stats() {
fi
}
+
+curpreswappages() {
+ pages=$(cat $XENBALLOON_PRESWAP_SYSFILE)
+ RETVAL=$pages
+ return # value returned in RETVAL in pages
+}
+
+preswaphysteresis() {
+ RETVAL=$XENBALLOON_PRESWAP_HYSTERESIS
+ if [ $xenstore_enabled = "true" ]; then
+ if xenstore-exists memory/preswaphysteresis ; then
+ RETVAL=`xenstore-read memory/preswaphysteresis`
+ fi
+ fi
+ return
+}
+
+preswapinertia() {
+ RETVAL=$XENBALLOON_PRESWAP_INERTIA
+ if [ $xenstore_enabled = "true" ]; then
+ if xenstore-exists memory/preswapinertia ; then
+ RETVAL=`xenstore-read memory/preswapinertia`
+ fi
+ fi
+ return
+}
+
+send_preswap_stats() {
+ if [ ! $xenstore_enabled = "true" ]; then
+ return
+ fi
+ curpreswappages
+ preswap_pgs=$RETVAL
+ if [ $XENBALLOON_SEND_PRESWAP ]; then
+ xenstore-write memory/preswap "$preswap_pgs"
+ fi
+}
+
+shrink_preswap() {
+ if [ "$XENBALLOON_PRESWAP_SHRINK" = "false" ]; then
+ return
+ fi
+ if [ ! -f "$XENBALLOON_PRESWAP_SYSFILE" ]; then
+ return
+ fi
+ curpreswappages
+ preswaplast=$preswapnow
+ preswapnow=$RETVAL
+ if [ $preswapnow -eq 0 -o $preswapnow -ne $preswaplast ]; then
+ preswapinertia
+ preswapinertiacounter=$RETVAL
+ return
+ fi
+ let "preswapinertiacounter=$preswapinertiacounter-1"
+ if [ $preswapinertiacounter -ne 0 ]; then
+ return
+ fi
+ preswaphysteresis
+ preswaphys=$RETVAL
+ if [ $preswaphys -eq 0 ]; then
+ return
+ fi
+ let "tgtpreswappages=$(( $preswapnow - \
+ ( $preswapnow / $preswaphys ) ))"
+ preswapinertia
+ preswapinertiacounter=$RETVAL
+ echo $tgtpreswappages > "$XENBALLOON_PRESWAP_SYSFILE"
+}
+
if [ ! -f /proc/xen/balloon ]; then
echo "$0: no balloon driver installed"
exit 0
@@ -165,6 +235,7 @@ else
echo "$0: missing /usr/bin/xenstore-* tools, disabling directed
ballooning"
xenstore_enabled=false
fi
+preswapnow=0
. /etc/sysconfig/xenballoon.conf
@@ -194,7 +265,9 @@ do
fi
interval=$XENBALLOON_INTERVAL
fi
+ shrink_preswap
send_memory_stats
+ send_preswap_stats
if [ $xenstore_enabled = "true" ]; then
if xenstore-exists memory/interval ; then
interval=`xenstore-read memory/interval`
diff -r 7f9286d21706 -r 8373971089a7 tools/xenballoon/xenballoond.init
--- a/tools/xenballoon/xenballoond.init Tue Jun 16 11:15:48 2009 +0100
+++ b/tools/xenballoon/xenballoond.init Tue Jun 16 11:17:28 2009 +0100
@@ -2,7 +2,7 @@
#
# xenballoond Script to start and stop Xen ballooning daemon.
#
-# Copyright (C) 2008 Oracle Corporation and/or its affiliates.
+# Copyright (C) 2009 Oracle Corporation and/or its affiliates.
# All rights reserved.
# Written by: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
#
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