units: run user service managers at OOM score adjustment 100

poettering · poettering · commit ce7de0ba8ef3 · 2021-10-04T16:27:10.000+02:00
Let's make it slightly more likely that a per-user service manager is killed than any system service. We use a conservative 100 (from a range that goes all the way to 1000). Replaces: systemd#17426 Together with the previous commit this means: system manager and system services are placed at OOM score adjustment 0 (specifically: they inherit kernel default of 0). User service manager (both for root and non-root) are placed at 100. User services for non-root are placed at 200, those for root inherit 100. Note that processes forked off the user *sessions* (i.e. not forked off the per-user service manager) remain at 0 (e.g. the shell process created by a tty or ssh login). This probably should be addressed too one day (maybe in pam_systemd?), but is not covered here.
diff --git a/units/user@.service.in b/units/user@.service.in
@@ -25,3 +25,4 @@ Delegate=pids memory
 TasksMax=infinity
 TimeoutStopSec=120s
 KeyringMode=inherit
+OOMScoreAdjust=100
