QA:Testcase Swap Based Killing

Description

This test case tests that systemd-oomd kills the largest swap consumer when swap used is greater 90% (or whatever limit was defined by systemd-oomd-defaults).

Setup

• This test case should be performed on either bare-metal or virtual machines.
• Check that you are running systemd 248~rc1 or higher with systemctl --version.
• Ensure the systemd-oomd-defaults package is installed (included with Fedora 34).
• Boot the system and log in as a regular user.

How to test

• Check that systemd-oomd is running:

systemctl status systemd-oomd

• Check that the systemd-oomd-defaults policy was applied by running oomctl and verifying that "/" is listed as a path under "Swap Monitored CGroups" along with the current swap usage.
• Now run the test:

systemd-run --user -r --unit systoomd_swap_test tail /dev/zero

• After verifying the results below, reset the unit:

systemctl --user reset-failed systoomd_swap_test.service

Expected Results

• systemd-oomd will have killed the unit started above. You can verify by checking for log lines that say something about "Swap used <...> is more than 90%" and "systemd-oomd killed <...> process(es)" with journalctl. The output of systemctl --user status systoomd_swap_test should say the unit is failed and killed (with no mention of oom-kill).
• Swap used should be below 90% (use free -h)