[Bug 1980169] Re: systemd-oomd without swap kill does nothing and we are back to no user space oom killer.

[Tim Richardson]

I look forward to testing it. I hope de-prioritization is not the same
as forbidding kill, to me it implies that the browser (for example)
will still be considered for killing but only after less privileged
targets are killed first. This would remove my earlier concern that it
would never be killed, leading to the situation we see now.

Regarding the package in proposed, what testing makes you convinced
that it is better than the current stable version?

On Thu, 30 Jun 2022 at 00:05, Nick Rosbrook <1980169 at bugs.launchpad.net> wrote:
>
> > The proposed upstream solution is to stop the browser being killed
>
> The proposed upstream solution is to allow all cgroups to configure the
> ManagedOOMPreference property, which would allow de-prioritizing
> critical desktop applications in the OOM kill queue. We use the browser
> as an example because based on user feedback, it seems that most users
> would want their browser to be *avoided* during OOM kill by default. Of
> course, this would only be a default and users would have the power to
> change this setting if desired.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1980169
>
> Title:
>   systemd-oomd without swap kill does nothing and we are back to no user
>   space oom killer.
>
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-- 
Tim Richardson

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https://bugs.launchpad.net/bugs/1980169

Title:
  systemd-oomd without swap kill does nothing and we are back to no user
  space oom killer.

Status in systemd package in Ubuntu:
  Won't Fix

Bug description:
  I have a 4GB Ram 2 core VM running a fresh install of 22.04 with proposed enabled.
  I have the latest systemd-oomd which no longer kills based on swap usage.

  In fact, it doesn't really kill at all, it seems.
  I have three times in a row made my session freeze with all the behaviour we see when there is no user space oom killer.

  To do this, I start chromium and use the trackthis.link site to load
  100 tabs (turn off pop-up blocking). For Firefox, it loads only 20
  tabs, which doesn't seem to quite use all memory. You can open a new
  tab and repeat the process to load another 20.

  Previously, systemd-oomd was killing the browser, although a few times
  I got it to kill the entire gnome session in a way I can not
  replicate, but it seems to happen when I am opening another app while
  the browsers are busy loading tabs.

  Now, it does not kill at all. I have a 2-core CPU load of > 70, 100%
  CPU, 100% swap and 99% Mem usage (in glances) and no interactive
  response. I have a Force Quit dialog for Firefox that is not
  responding, my two terminal windows  do not respond. This is really
  basically the same as the bad old days when we could wait a long time
  for the kernel killer to work, or we just give up on the session and
  reboot.

  Far be it from me to give advice, but it doesn't look to me that
  systemd-oomd is going to work with default Ubuntu swap config. This is
  now out of the frying pan and into the fire.

  I tested earlyoom too. It is completely predictable. It always kills
  the browser, it has never killed the session.

  Firefox and Chrome are supposed to discard tabs, but this process is
  much too slow to fight the rapid loading of tabs in this test case.

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