nixos/preload: init

(cherry picked from commit a0f5d5e500b4c7ddf619333a0341a049e1e345ee)

3 files changed, 34 insertions, 0 deletions

diff --git a/nixos/doc/manual/release-notes/rl-2311.section.md b/nixos/doc/manual/release-notes/rl-2311.section.md
index 640e46e861a2f..715ae997af435 100644
--- a/nixos/doc/manual/release-notes/rl-2311.section.md
+++ b/nixos/doc/manual/release-notes/rl-2311.section.md
@@ -152,6 +152,8 @@
 
 - [c2FmZQ](https://github.com/c2FmZQ/c2FmZQ/), an application that can securely encrypt, store, and share files, including but not limited to pictures and videos. Available as [services.c2fmzq-server](#opt-services.c2fmzq-server.enable).
 
+- [preload](http://sourceforge.net/projects/preload), a service that makes applications run faster by prefetching binaries and shared objects.  Available as [services.preload](#opt-services.preload.enable).
+
 ## Backward Incompatibilities {#sec-release-23.11-incompatibilities}
 
 - `services.postgresql.ensurePermissions` has been deprecated in favor of `services.postgresql.ensureUsers.*.ensureDBOwnership` which simplifies the setup of database owned by a certain system user
diff --git a/nixos/modules/module-list.nix b/nixos/modules/module-list.nix
index f4ca96d2ca161..fe2e0aed24842 100644
--- a/nixos/modules/module-list.nix
+++ b/nixos/modules/module-list.nix
@@ -722,6 +722,7 @@
   ./services/misc/podgrab.nix
   ./services/misc/polaris.nix
   ./services/misc/portunus.nix
+  ./services/misc/preload.nix
   ./services/misc/prowlarr.nix
   ./services/misc/pufferpanel.nix
   ./services/misc/pykms.nix
diff --git a/nixos/modules/services/misc/preload.nix b/nixos/modules/services/misc/preload.nix
new file mode 100644
index 0000000000000..19b2531087dd6
--- /dev/null
+++ b/nixos/modules/services/misc/preload.nix
@@ -0,0 +1,31 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.preload;
+in {
+  meta = { maintainers = pkgs.preload.meta.maintainers; };
+
+  options.services.preload = {
+    enable = mkEnableOption "preload";
+    package = mkPackageOption pkgs "preload" { };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.preload = {
+      description = "Loads data into ram during idle time of CPU.";
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        EnvironmentFile = "${cfg.package}/etc/conf.d/preload";
+        ExecStart = "${getExe cfg.package} --foreground $PRELOAD_OPTS";
+        Type = "simple";
+        # Only preload data during CPU idle time
+        IOSchedulingClass = 3;
+        DynamicUser = true;
+        StateDirectory = "preload";
+      };
+    };
+  };
+}