How to use the command "oomctl" (with examples)

“oomctl” is a command-line tool that is part of the systemd-oomd package. It allows users to analyze the current state of the cgroups and system contexts stored by systemd-oomd. This tool is useful for understanding the memory management and out-of-memory (OOM) behavior of the system.

Use case 1: Show the current state of the cgroups and system contexts stored by systemd-oomd

Code:

oomctl dump

Motivation:

As a system administrator, it is important to have visibility into the current state of the cgroups and system contexts managed by systemd-oomd. By using the “oomctl dump” command, we can quickly gather information about the memory usage and OOM behavior of the system. This can help us diagnose any issues related to memory constraints or resource allocation.

Explanation:

• “oomctl” is the command that we are executing.
• “dump” is the subcommand that we are using. It instructs “oomctl” to display the current state of the cgroups and system contexts stored by systemd-oomd.

Example output:

Path                      Control Group                                              Swap Current                    RSS Current                    Ignore
system.slice/             [                       0]                         [                       0] 2.0Mi                    [                       1]
user.slice/               [                       0]                         [                       0] 4.0Ki                    [                       1]
init.scope/               [                       0]                         [                       0] 4.0Ki                    [                       1]

Conclusion:

The “oomctl dump” command is a powerful tool for analyzing the state stored in systemd-oomd. By using this command, we can obtain insights into the memory usage and OOM behavior of the system, which can be invaluable for troubleshooting and performance tuning purposes.