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Message #138261
[Bug 1476211] Re: kswapd takes 100% CPU although there is no swap
I have similar behaviour on my Ubuntu 15.04, Intel Atom D2500 Dual LAN,
Dual COM Fanless Mini-ITX PC with 4 GB RAM and 128 GB SSD.
In few days after reboot kswapd0 starts to take 100% CPU (see
highlighted row here
https://gist.github.com/SamSoldatenko/83eaf196721bc51d7d55#file-
gistfile1-txt-L29 ). No load. 3Gb free memory (out of 4), 10Gb swap
space.
$ uname -a
Linux minisrv1 3.19.0-26-generic #28-Ubuntu SMP Tue Aug 11 14:16:45 UTC 2015 i686 i686 i686 GNU/Linux
$ sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
CCCDT10N.86A.0032.2012.0323.1510
03/23/2012
$ uptime
22:39:01 up 8 days, 5:43, 1 user, load average: 1.34, 1.23, 1.23
$ sudo ps auxf
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 2 0.0 0.0 0 0 ? S Sep26 0:15 [kthreadd]
root 3 0.0 0.0 0 0 ? S Sep26 4:39 \_ [ksoftirqd/0]
root 5 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [kworker/0:0H]
root 7 0.6 0.0 0 0 ? S Sep26 76:29 \_ [rcu_sched]
root 8 0.0 0.0 0 0 ? S Sep26 0:00 \_ [rcu_bh]
root 9 0.5 0.0 0 0 ? S Sep26 64:30 \_ [migration/0]
root 10 0.2 0.0 0 0 ? S Sep26 23:57 \_ [watchdog/0]
root 11 0.2 0.0 0 0 ? S Sep26 26:02 \_ [watchdog/1]
root 12 0.6 0.0 0 0 ? S Sep26 75:46 \_ [migration/1]
root 13 0.0 0.0 0 0 ? S Sep26 4:38 \_ [ksoftirqd/1]
root 15 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [kworker/1:0H]
root 16 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [khelper]
root 17 0.0 0.0 0 0 ? S Sep26 0:00 \_ [kdevtmpfs]
root 18 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [netns]
root 19 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [perf]
root 20 0.0 0.0 0 0 ? S Sep26 0:05 \_ [khungtaskd]
root 21 0.0 0.0 0 0 ? S< Sep26 0:01 \_ [writeback]
root 22 0.0 0.0 0 0 ? SN Sep26 0:00 \_ [ksmd]
root 23 0.0 0.0 0 0 ? SN Sep26 0:40 \_ [khugepaged]
root 24 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [crypto]
root 25 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [kintegrityd]
root 26 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [bioset]
root 27 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [kblockd]
root 28 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [ata_sff]
root 29 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [md]
root 30 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [devfreq_wq]
root 34 31.5 0.0 0 0 ? R Sep26 3748:10 \_ [kswapd0]
root 35 0.0 0.0 0 0 ? S Sep26 0:00 \_ [fsnotify_mark]
root 36 0.0 0.0 0 0 ? S Sep26 0:00 \_ [ecryptfs-kthrea]
root 48 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [kthrotld]
root 49 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [acpi_thermal_pm]
root 51 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [ipv6_addrconf]
root 70 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [deferwq]
root 71 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [charger_manager]
root 118 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [kpsmoused]
root 119 0.0 0.0 0 0 ? S Sep26 0:00 \_ [scsi_eh_0]
root 120 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [scsi_tmf_0]
root 121 0.0 0.0 0 0 ? S Sep26 0:00 \_ [scsi_eh_1]
root 122 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [scsi_tmf_1]
root 123 0.0 0.0 0 0 ? S Sep26 0:00 \_ [scsi_eh_2]
root 124 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [scsi_tmf_2]
root 125 0.0 0.0 0 0 ? S Sep26 0:00 \_ [scsi_eh_3]
root 126 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [scsi_tmf_3]
root 138 0.0 0.0 0 0 ? S Sep26 0:57 \_ [jbd2/sda1-8]
root 139 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [ext4-rsv-conver]
root 181 0.0 0.0 0 0 ? S Sep26 0:00 \_ [kauditd]
root 297 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [hd-audio0]
root 310 0.0 0.0 0 0 ? S< Sep26 0:50 \_ [kworker/1:1H]
root 311 0.0 0.0 0 0 ? S< Sep26 0:56 \_ [kworker/0:1H]
root 602 0.0 0.0 0 0 ? S< Sep26 0:00 \_ [cfg80211]
root 5464 0.1 0.0 0 0 ? S 15:14 0:51 \_ [kworker/1:2]
root 6065 0.3 0.0 0 0 ? S 17:12 1:13 \_ [kworker/0:1]
root 7237 0.4 0.0 0 0 ? S 20:54 0:29 \_ [kworker/1:0]
root 7648 0.0 0.0 0 0 ? S 22:15 0:00 \_ [kworker/0:0]
root 7732 1.0 0.0 0 0 ? S 22:15 0:15 \_ [kworker/u8:0]
root 7839 0.4 0.0 0 0 ? S 22:31 0:02 \_ [kworker/u8:2]
root 1 0.1 0.4 20180 18464 ? Ss Sep26 12:28 /sbin/init text
root 234 0.0 0.0 9416 3428 ? Ss Sep26 4:27 /lib/systemd/systemd-journald
root 237 0.0 0.0 13224 3428 ? Ss Sep26 0:00 /lib/systemd/systemd-udevd
systemd+ 378 0.0 0.0 12424 2200 ? Ssl Sep26 0:22 /lib/systemd/systemd-timesyncd
whoopsie 547 0.1 0.2 73256 11208 ? Ssl Sep26 14:21 /usr/bin/whoopsie -f
root 570 0.0 0.0 5572 2768 ? Ss Sep26 0:59 /usr/sbin/cron -f
root 573 0.0 0.2 41140 8560 ? Ssl Sep26 1:20 /usr/sbin/ModemManager
syslog 574 0.0 0.5 50220 22236 ? Ssl Sep26 1:03 /usr/sbin/rsyslogd -n
avahi 575 0.0 0.0 3736 2816 ? Ss Sep26 0:53 avahi-daemon: running [minisrv1-3.local]
avahi 583 0.0 0.0 3616 212 ? S Sep26 0:00 \_ avahi-daemon: chroot helper
root 585 1.1 0.3 82884 13480 ? Ssl Sep26 141:59 /usr/sbin/NetworkManager --no-daemon
root 684 0.0 0.1 9300 4564 ? S Sep26 0:00 \_ /sbin/dhclient -d -q -sf /usr/lib/NetworkManager/nm-dhcp-helper -pf /run/sendsigs.omit.d/network-manager.dhclient-eth0.pid -lf /var/lib/NetworkManager/dhclient-eba3cda0-1d2d-4db7-a1dd-a90fde49ac32-eth0.lease -cf /var/lib/NetworkManager/dhclient-eth0.conf eth0
nobody 687 0.0 0.0 6724 3104 ? S Sep26 3:53 \_ /usr/sbin/dnsmasq --no-resolv --keep-in-foreground --no-hosts --bind-interfaces --pid-file=/run/sendsigs.omit.d/network-manager.dnsmasq.pid --listen-address=127.0.1.1 --conf-file=/var/run/NetworkManager/dnsmasq.conf --cache-size=0 --proxy-dnssec --enable-dbus=org.freedesktop.NetworkManager.dnsmasq --conf-dir=/etc/NetworkManager/dnsmasq.d
message+ 597 0.1 0.0 5836 3616 ? Ss Sep26 13:29 /usr/bin/dbus-daemon --system --address=systemd: --nofork --nopidfile --systemd-activation
postgres 614 0.0 0.3 193456 14268 ? S Sep26 1:15 /usr/lib/postgresql/9.4/bin/postgres -D /var/lib/postgresql/9.4/main -c config_file=/etc/postgresql/9.4/main/postgresql.conf
postgres 645 0.0 0.0 193456 3184 ? Ss Sep26 0:01 \_ postgres: checkpointer process
postgres 646 0.0 0.0 193456 2336 ? Ss Sep26 2:02 \_ postgres: writer process
postgres 647 0.0 0.0 193456 3260 ? Ss Sep26 2:03 \_ postgres: wal writer process
postgres 648 0.0 0.1 193756 5480 ? Ss Sep26 1:18 \_ postgres: autovacuum launcher process
postgres 649 0.0 0.0 50968 3576 ? Ss Sep26 0:24 \_ postgres: stats collector process
root 621 0.0 0.2 39420 11204 ? Ssl Sep26 2:12 /usr/lib/policykit-1/polkitd --no-debug
root 622 0.0 0.1 21832 6580 ? Ssl Sep26 1:37 /usr/sbin/cups-browsed
root 661 0.0 0.1 8580 4880 ? Ss Sep26 4:43 /usr/sbin/sshd -D
root 9944 0.0 0.1 11872 5640 ? Ss Oct02 0:00 \_ sshd: git [priv]
root 7641 0.0 0.1 11872 5860 ? Ss 22:15 0:00 \_ sshd: sam [priv]
sam 7716 0.2 0.0 12004 3204 ? S 22:15 0:03 \_ sshd: sam@pts/0
sam 7717 0.1 0.1 7572 5088 pts/0 Ss 22:15 0:02 \_ -bash
root 7882 0.0 0.0 6800 3648 pts/0 S+ 22:40 0:00 \_ sudo ps auxf
root 7883 0.0 0.0 5316 2388 pts/0 R+ 22:40 0:00 \_ ps auxf
root 670 0.0 0.0 4740 1928 tty1 Ss+ Sep26 0:00 /sbin/agetty --noclear tty1 linux
kernoops 879 0.0 0.0 7116 2616 ? Ss Sep26 0:23 /usr/sbin/kerneloops
root 1704 0.0 0.0 42560 992 ? Ss Sep26 0:00 nginx: master process /usr/sbin/nginx -g daemon on; master_process on;
www-data 1705 0.1 0.0 42692 2912 ? S Sep26 17:17 \_ nginx: worker process
www-data 1706 0.1 0.0 42692 2912 ? S Sep26 17:31 \_ nginx: worker process
www-data 1707 0.0 0.0 42692 2912 ? S Sep26 0:00 \_ nginx: worker process
www-data 1708 0.1 0.0 42692 2912 ? S Sep26 17:41 \_ nginx: worker process
root 6137 0.0 0.0 4400 2044 ? Ss Sep26 3:52 /usr/sbin/irqbalance --pid=/var/run/irqbalance.pid
root 6487 0.0 0.1 46964 6536 ? Ssl Sep26 4:35 /usr/sbin/thermald --no-daemon --dbus-enable
git 7916 0.0 0.0 5684 3912 ? Ss Sep26 0:00 /lib/systemd/systemd --user
git 7917 0.0 0.0 7012 852 ? S Sep26 0:00 \_ (sd-pam)
root 5378 0.0 0.1 12496 5108 ? Ss Sep27 0:00 /usr/sbin/cupsd -l
root 8072 0.0 0.1 8468 6796 ? Ss Oct02 0:34 /lib/systemd/systemd-logind
sam 7645 0.0 0.1 5684 4120 ? Ss 22:15 0:00 /lib/systemd/systemd --user
sam 7646 0.0 0.3 21148 15116 ? S 22:15 0:00 \_ (sd-pam)
$ free -m
total used free shared buffers cached
Mem: 4020 1027 2993 54 2 124
-/+ buffers/cache: 900 3120
Swap: 10220 10 10210
$ sudo swapon -s
Filename Type Size Used Priority
/dev/sda5 partition 2077692 10952 -1
/swapfile file 8388604 0 -2
--
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https://bugs.launchpad.net/bugs/1476211
Title:
kswapd takes 100% CPU although there is no swap
Status in linux package in Ubuntu:
Confirmed
Bug description:
On a notebook with neither swap partition nor swap file (because of
SSD and surplus of RAM), kswapd0 suddenly runs amok and takes 100% of
CPU activity. When this happens, usually at most 5.5 of 8 GB RAM were
in use, so there is no reason to swap.
This happens so suddenly, that no user input is possible anymore, eg.
I can barely switch to tty to kill processes that take most RAM. The
processor becomes extremely hot and I can only turn the computer off
and reboot. I consider this as critical and harmful to my hardware.
I noticed that Ubuntu installs by default with swappiness 60. Now I
changed that to 10 because I would never encounter the case that 8GB
are in use, but it didn't have an effect.
Expected behavior:
- on systems without RAM, kswapd should never attempt to swap
- if there is not enough RAM, kernel should kill processes to free up RAM
- no process should be able to claim so much CPU activity, that the computer becomes unresponsive (it should always be possible to control/stop/kill processes over tty)
Actual behavior:
- kswapd tries to swap although there is no swap space
ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: linux-image-3.19.0-22-generic 3.19.0-22.22
ProcVersionSignature: Ubuntu 3.19.0-22.22-generic 3.19.8-ckt1
Uname: Linux 3.19.0-22-generic x86_64
ApportVersion: 2.17.2-0ubuntu1.1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: andreas 2368 F.... pulseaudio
/dev/snd/controlC0: andreas 2368 F.... pulseaudio
CurrentDesktop: Unity
Date: Mon Jul 20 12:49:24 2015
EcryptfsInUse: Yes
InstallationDate: Installed on 2015-06-06 (43 days ago)
InstallationMedia: Ubuntu 15.04 "Vivid Vervet" - Release amd64 (20150422)
MachineType: LENOVO 20266
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.19.0-22-generic root=UUID=8a0dc2f3-fcf3-4e5b-8e23-1441bd36e3dc ro noprompt persistent quiet splash acpi_backlight=vendor vt.handoff=7 init=/sbin/upstart
RelatedPackageVersions:
linux-restricted-modules-3.19.0-22-generic N/A
linux-backports-modules-3.19.0-22-generic N/A
linux-firmware 1.143.1
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 10/31/2013
dmi.bios.vendor: LENOVO
dmi.bios.version: 76CN31WW
dmi.board.asset.tag: No Asset Tag
dmi.board.name: Yoga2
dmi.board.vendor: LENOVO
dmi.board.version: 31900058STD
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: Lenovo Yoga 2 Pro
dmi.modalias: dmi:bvnLENOVO:bvr76CN31WW:bd10/31/2013:svnLENOVO:pn20266:pvrLenovoYoga2Pro:rvnLENOVO:rnYoga2:rvr31900058STD:cvnLENOVO:ct10:cvrLenovoYoga2Pro:
dmi.product.name: 20266
dmi.product.version: Lenovo Yoga 2 Pro
dmi.sys.vendor: LENOVO
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References
