Bug 2036552

Summary:	RFE: tmux needs to put each process into its own systemd scope
Product:	[Fedora] Fedora	Reporter:	Chris Murphy <bugzilla>
Component:	tmux	Assignee:	Sven Lankes <sven>
Status:	CLOSED ERRATA	QA Contact:	Fedora Extras Quality Assurance <extras-qa>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	rawhide	CC:	bberg, dcantrell, rosset.filipe, strobert, sven, the.anitazha
Target Milestone:	---
Target Release:	---
Hardware:	Unspecified
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Fixed In Version:	tmux-3.3a-1.fc36	Doc Type:	If docs needed, set a value
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Last Closed:	2022-08-24 20:30:53 UTC	Type:	Bug
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
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Embargoed:

Description Chris Murphy 2022-01-03 03:18:05 UTC

Description of problem:

Running makedeltaiso and it's running out of memory, so sd-oomd is clobbering the scope. The problem is that tmux is adding all the sessions to a single scope, so when oomd kills that scope it kills all of tmux and its sesssions.

So tmux needs to learn how to put each shell into its own scope, similar to what GNOME Terminal already knows how to do.


Version-Release number of selected component (if applicable):


How reproducible:
Always


Steps to Reproduce:
1. tmux, create a few sessions
2. in one of the sessions find a way to use up too much RAM like stress or makedeltaiso (what i'm doing) on two 2G ISOs on a 4G RAM system
3.

Actual results:

oomd clobbers the entire scope tmux is in, which includes all processes running in tmux


Expected results:

tmux should create a separate systemd scope for each pane/session/shell that gets started, so that those shell processes are running in their own cgroup, and thus can be independently killed by sd-oomd rather than taking down all sessions running in tmux


Additional info:

Comment 1 Chris Murphy 2022-01-03 03:19:42 UTC

On Fedora with GNOME, vte moves each process into its own scope, and thus its own cgroup assignment. This isn't happening for tmux processes.

The code is here: https://gitlab.gnome.org/GNOME/vte/-/blob/master/src/systemd.cc

Comment 2 Chris Murphy 2022-01-03 03:20:25 UTC

Jan 02 20:08:10 fnuc.local systemd-oomd[648]: Killed /user.slice/user-1000.slice/session-9.scope due to memory used (3948032000) / total (4024205312) and swap used (3631742976) / total (40233820>
Jan 02 20:08:10 fnuc.local systemd[1]: session-9.scope: systemd-oomd killed 7 process(es) in this unit.
Jan 02 20:08:12 fnuc.local systemd[1]: session-9.scope: Deactivated successfully.
Jan 02 20:08:12 fnuc.local systemd[1]: session-9.scope: Consumed 31min 21.423s CPU time.
Jan 02 20:08:12 fnuc.local systemd-logind[692]: Removed session 9.

Comment 3 Sven Lankes 2022-01-03 09:00:18 UTC

Nice idea but I don't think it does fit into tmux as a gerneric terminal multiplexer. Feel free to discuss with upstream @ https://github.com/tmux/tmux what their thoughts are.

I will leave this ticket open for reference but I am not going to work on it.

Comment 4 Benjamin Berg 2022-01-03 11:29:36 UTC

I opened https://github.com/tmux/tmux/issues/3024 about it.

Comment 5 Dave Cantrell 2022-01-04 15:53:05 UTC

Following the upstream issue to see where that goes and will then update the package accordingly (assuming anything happens upstream with the request).

Thanks.

Comment 6 Fedora Update System 2022-08-19 04:01:49 UTC

FEDORA-2022-8985737e34 has been submitted as an update to Fedora 36. https://bodhi.fedoraproject.org/updates/FEDORA-2022-8985737e34

Comment 7 Fedora Update System 2022-08-20 02:23:36 UTC

FEDORA-2022-8985737e34 has been pushed to the Fedora 36 testing repository.
Soon you'll be able to install the update with the following command:
`sudo dnf upgrade --enablerepo=updates-testing --refresh --advisory=FEDORA-2022-8985737e34`
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2022-8985737e34

See also https://fedoraproject.org/wiki/QA:Updates_Testing for more information on how to test updates.

Comment 8 Fedora Update System 2022-08-24 20:30:53 UTC

FEDORA-2022-8985737e34 has been pushed to the Fedora 36 stable repository.
If problem still persists, please make note of it in this bug report.