Enable large page support for databases

nixos/module/default.nix

@@ -8,6 +8,7 @@
     datacow
     email
     ephemeral
+    hugepages
     iosched
     kernel
     locale-en_EU

nixos/module/hugepages.nix

@@ -0,0 +1,4 @@
+{ ... }: { config, lib, pkgs, ... }: {
+  services.postgresql.settings.huge_pages = lib.mkDefault true;
+  services.mysql.settings.mysqld.large_pages = lib.mkDefault true;
+}