The Ubuntu 26.10 desktop is adjusting its default out-of-memory (OOM) daemon behavior when dealing with memory pressure on the system.

Jean Baptiste Lallement of Canonical's Ubuntu Desktop Team outlined changes being made to Ubuntu 26.10 by default for better deciding what programs to terminate should the Ubuntu desktop become memory starved. The intent is on addressing issues currently seen where the GNOME Shell, D-Bus, or other key programs could accidentally terminate under OOM pressure and in turn render the system inoperable.

Ubuntu 26.10 is changing its default OOM policy to try to ensure critical desktop services will be less likely to be killed while other applications and background services would be first when encountering significant memory pressure.

The Ubuntu Discourse post sums up the changes as:

"The new policy gives critical desktop services more protection:

- Critical desktop services now use a lower OOM score, making them less likely to be selected by the kernel OOM killer.

- Applications and background services keep a higher default score, so they remain more likely to be terminated first.

- The automatic systemd-oomd memory-pressure kill for the whole user session is disabled. systemd-oomd does not use the same OOM priority scores as the kernel. It could then terminate a critical desktop service based on memory pressure alone.
Of course, this does not prevent applications from being terminated when the system runs out of memory, and it does not make Ubuntu immune to OOM conditions.

The goal is simply to preserve the desktop session where possible, and terminate applications before the services needed to keep that session running."

Further improvements for Ubuntu Linux around its OOM behavior are expected to happen beyond next month's Ubuntu 26.10 release.