Launched apps are not in their own cgroup

Distribution

21.3

Package version

6.0.4

Graphics hardware in use

N/A

Frequency

Always

Bug description

When launching an application (e.g. a shortcut pinned to the panel), the launched application is a part of the same cgroup as the DE itself, rather than in its own cgroup. This means that various system monitor apps (e.g. Mission Center) show launched applications as a subprocess of cinnamon, rather than actually an application.

Steps to reproduce

Launch an application (e.g. Firefox), then look for it in the Applications section of a task manager/system monitor utility (e.g. Mission Center).

Expected behavior

When applications are launched, they should be given their own cgroup, rather than using the DE's cgroup.

Additional information

From https://gitlab.com/mission-center-devs/mission-center/-/issues/102#note_1669993731:

I've set up a VM with the latest version of Linux Mint and looked into this bug.

Currently Mission Center does some very simple heuristics to try to determine running apps, but the bulk of the logic relies on the DE registering a cgroup for each app a user launches. Linux Mint's Cinnamon does not do that, and thus a lot of running apps do not show up in the app list.

While some logic could be added to the app to be able detect running apps without the help from the DE this creates a large maintenance burden and yields a very brittle and unreliable result.

Fixing this issue upstream should result in Mission Center and similar applications working as expected.

The issue names no source file or test; start by tracing Cinnamon's application-launch path for a panel shortcut and comparing the launched process cgroup with Cinnamon's. Reproduce with Firefox and inspect it in Mission Center or a similar system monitor. Done means launched applications receive their own cgroup and appear as applications rather than Cinnamon subprocesses.