1ea910f662
Nothing stood between "memory is tight" and "processes die at random": the kernel OOM killer only fires after an allocation has already failed, so a machine under pressure thrashes in reclaim until something breaks somewhere fatal — seen in practice as Hyprland taking SIGBUS mid-memcpy from a client shm pool that memory pressure was tearing down. Enable systemd-oomd, which keys on PSI stall time rather than free pages, and mark app.slice — and only app.slice — as its kill candidate. Hyprland runs in session.slice, so the compositor is structurally ineligible as a victim: oomd takes the app that caused the pressure and the session survives. Thresholds (50% stall over 20s, Fedora's desktop defaults) live in an oomd.conf.d drop-in; candidacy ships as a vendor drop-in under /usr/lib/systemd/user so existing users get it on package upgrade with no per-user seeding. New installs enable the daemon from enable-services.sh; a migration covers existing ones, restarting an already-running oomd so it doesn't keep stale thresholds until reboot. Deliberately not earlyoom: it triggers only when free RAM and free swap are both under threshold, so Omarchy's large, mostly-idle swapfiles keep it asleep through exactly this failure. Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
17 lines
835 B
Plaintext
17 lines
835 B
Plaintext
# Make user apps the only thing systemd-oomd is allowed to kill.
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#
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# Hyprland runs in session.slice, as wayland-wm@hyprland.desktop.service, while
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# everything launched through uwsm-app lands in app.slice/app-*.scope. Marking
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# only app.slice as a kill candidate means the compositor is structurally
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# ineligible: oomd takes the browser or terminal that caused the pressure, and
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# the session survives to show the notification about it. Setting this on
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# user@.service instead would put the compositor back in the candidate pool.
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#
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# Swap kill is a backstop for the slower shape of the same problem, where swap
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# fills before pressure spikes. It uses the global SwapUsedLimit (90%) from
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# /etc/systemd/oomd.conf.d/10-omarchy.conf, which also carries the pressure
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# thresholds.
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[Slice]
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ManagedOOMMemoryPressure=kill
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ManagedOOMSwap=kill
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