# Without an OOM daemon there is nothing between "memory is tight" and
# "processes start dying at random". The kernel OOM killer only fires once an
# allocation has already failed outright, which is far too late for the
# desktop: the machine thrashes in reclaim until something fails somewhere
# fatal. Seen in practice as Hyprland taking SIGBUS mid-memcpy from a Wayland
# client's shm pool, because the client was being torn down by the same memory
# pressure. One app misbehaving should not cost the whole session.
#
# systemd-oomd keys on PSI stall time rather than on free pages, so it acts
# while the machine is still thrashing instead of after an allocation failed.
# Deliberately not earlyoom: that fires only when free RAM *and* free swap are
# both under threshold, so a large, mostly-unused swapfile keeps it asleep
# through exactly this failure.
#
# 50% means half of a ten-second window was spent stalled on memory reclaim.
# Held for 20s straight, the desktop is already unusable and losing one app is
# the cheaper outcome. Which cgroups are eligible is set separately, in
# /usr/lib/systemd/user/app.slice.d/10-oomd.conf.
[OOM]
DefaultMemoryPressureDurationSec=20s
DefaultMemoryPressureLimit=50%