kernel-packages team mailing list archive

["Andreas E." <1476211@xxxxxxxxxxxxxxxxxx>]

[[Ubuntu does not provide an update path for (these) Lenovo BIOS. Maybe
it would be nice to have a solution for this as well, to avoid users
being bound to buggy and outdated BIOS. To add, the given instructions
to the wiki seem very abandonned and do not (not all) apply to nowadays
ROMs of >10MB. Figuring that out cost me a day. ]]

After installing the Win8/BIOS, the problem still occurs.
  sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
  76CN43WW
  03/30/2015

When I intentionally launch so many applications to trigger the freezes, I noticed that `top` displays actually different numbers:
  KiB Mem:  8085948 total, 8023384 used,   62564 free,    3564 buffers
  KiB Swap:       0 total,       0 used,       0 free. 2976336 cached Mem
The before mentioned numbers were from Gnome system monitor (oh!), which always displays only 5GB / 65% of RAM. This time had also top opened before the freeze.
Do I interprete it right that under these conditions the memory is indeed full and that system monitor displays (used‒cached) ?

The laptop was still frozen about 10min until the Kernel decided (or was
able to) kill processes and became repsonsive again. On a second test,
it didn't become responsive even after 20min.

So concluding,
• there could be a bug in system monitor to display (used ‒ cached) RAM
• I still don't know what it is doing within these 10 – ∞ minutes. I still think the Kernel should be able to start killing processes (earlier), or there should be warnings that can take effect before the computer becomes unresponsive. 

** Changed in: linux (Ubuntu)
       Status: Incomplete => Confirmed

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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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