hydra: berlin: Add earlyoom service.

* hydra/berlin.scm: Add ‘earlyoom-service-type’ instance.

hydra/berlin.scm

@@ -19,7 +19,8 @@
              ((guix build utils) #:select (find-files))
              (srfi srfi-1)
              (ice-9 match))
-(use-service-modules avahi base databases dns mcron monitoring networking admin
+(use-service-modules avahi base databases dns linux
+                     mcron monitoring networking admin
                      rsync shepherd ssh vpn web)
 (use-package-modules admin base certs databases disk emacs linux mail monitoring
                      screen ssh tls tor vim package-management
@@ -509,6 +510,9 @@ An incremental send is attempted if a PARENT snapshot is provided."
              (service avahi-service-type
                       (avahi-configuration (debug? #t)))
 
+             ;; Don't let greedy processes put the machine to its knees.
+             (service earlyoom-service-type)
+
              ;; Periodically populate the Disarchive database.  Store it
              ;; under /gnu, which is the big drive; talk directly to the
              ;; local Cuirass instance.