Whitelisting a process by name

[D3vil0p3r]

Hello,
I'm trying to whitelist a process to avoid that OOM nohang kills it. What I'm trying to whitelist is gnome-shell process, and for doing this, I edited /etc/nohang/nohang.conf and I added:

##  7.2.1. Matching process names with RE patterns to change their badness
##  Example:
#   @BADNESS_ADJ_RE_NAME 200 /// ^Web Content$
@BADNESS_ADJ_RE_NAME 0 /// ^gnome-shell$

but when I run a process that makes gnome-shell to use a lot of resources, by journalctl I'm still getting:

oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0,global_oom,task_memcg=/user.slice/user-1000.slice/[email protected]/session.slice/[email protected],task=gnome-shell,pid=47368,uid=1000
Out of memory: Killed process 47368 (gnome-shell) total-vm:4065984kB, anon-rss:136kB, file-rss:9228kB, shmem-rss:20kB, UID:1000 pgtables:1432kB oom_score_adj:200

and my user session restarts always.

How can I whitelist gnome-shell or a process by name in nohang?

[hakavlad]

Hi!

@BADNESS_ADJ_RE_NAME -900  /// ^gnome-shell$

should work.

Out of memory: Killed process 47368 (gnome-shell)

It looks like nohang didn't work at all - the kernel's OOM killer worked instead.

[D3vil0p3r]

@hakavlad does nohang override kernel's OOM killer settings?

[hakavlad]

nohang should work earlier than kernel's OOMK.

[hakavlad]

Did you change something else in the config?

[hakavlad]

does nohang override kernel's OOM killer settings?

No. They work independently of each other.

[D3vil0p3r]

does nohang override kernel's OOM killer settings?

No. They work independently of each other.

I think that the crash was caused nt by nohang but by kernel's OOM killer... In the config I didn't change other things.

[hakavlad]

Is the service running at all? What's in the status?

sudo systemctl status nohang
sudo systemctl status nohang-desktop

[hakavlad]

How much swap space do you have?

[hakavlad]

What's in the journal?
sudo journalctl -eu nohang
sudo journalctl -eu nohang-desktop

[D3vil0p3r]

Is the service running at all? What's in the status?

sudo systemctl status nohang
sudo systemctl status nohang-desktop

Yes, the nohang service is running and active. I don't use nohang-desktop.

Swap Space: 8GB

About the journalctl -eu nohang:

Dec 30 22:20:00 penthost systemd[1]: Started Sophisticated low memory handler.
Dec 30 22:20:00 penthost nohang[1858]: Starting nohang with config /etc/nohang/nohang.conf
Dec 30 22:20:00 penthost nohang[1858]: Monitoring has started!
Dec 30 22:20:27 penthost systemd[1]: Stopping Sophisticated low memory handler...
Dec 30 22:20:27 penthost nohang[1858]: Got the SIGTERM signal
Dec 30 22:20:27 penthost nohang[1858]: No corrective actions applied in the last 26.5s
Dec 30 22:20:27 penthost nohang[1858]: Process time: 0.08s (average: 0.3%); exit.
Dec 30 22:20:27 penthost systemd[1]: nohang.service: Deactivated successfully.
Dec 30 22:20:27 penthost systemd[1]: Stopped Sophisticated low memory handler.
Dec 30 22:20:27 penthost systemd[1]: Started Sophisticated low memory handler.
Dec 30 22:20:27 penthost nohang[1998]: Starting nohang with config /etc/nohang/nohang.conf
Dec 30 22:20:27 penthost nohang[1998]: Monitoring has started!

For nohang-desktop no entries (because I use only nohang).

In your opinion, could be effective to disable the kernel's OOM killer and use only nohang? I set vm.overcommit_memory = 0 but it seems I'm still getting kill on gnome-shell. How can I disable the kernel's OOM killer and use only nohang?

[hakavlad]

In your opinion, could be effective to disable the kernel's OOM killer

I'm not sure this is even possible. Do you have any idea how to do it?

btw, what kernel version are you using? Is MGLRU enabled?

I set vm.overcommit_memory = 0

It is default value typically. It does not turn off kernel's OOMK.