add earlyoom to citadel and reduce swap

hosts/citadel/default.nix

@@ -80,7 +80,7 @@ in {
   swapDevices = [
     {
       device = "/.swapvol/swapfile";
-      size = 32 * 1024;
+      size = 4 * 1024;
     }
   ];
 
@@ -99,6 +99,11 @@ in {
       #     ${pkgs.xorg.xmodmap}/bin/xmodmap -e "keycode 46 = l L Right L"
       # '';
     };
+  # enable oom killer when system ram drops below 5% free
+    earlyoom = {
+      enable = true;
+      freeMemThreshold = 5; # <%5 free
+    };
   };
 
   # fix cpu throttling on Lenovo Thinkpad

hosts/semita/default.nix

@@ -108,7 +108,7 @@ in {
   swapDevices = [
     {
       device = "/.swapvol/swapfile";
-      size = 32 * 1024;
+      size = 4 * 1024;
     }
   ];