From f41e6c0a743933e094f3fbddcf49bb6a79489c40 Mon Sep 17 00:00:00 2001
From: h7x4 <h7x4@nani.wtf>
Date: Tue, 21 Jul 2026 17:52:15 +0900
Subject: [PATCH] bicep/postgresql: enable hugepages

---
 flake.nix                                   | 1 +
 hosts/bicep/services/postgresql/default.nix | 8 +++++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/flake.nix b/flake.nix
index 9c502f9..84a5f86 100644
--- a/flake.nix
+++ b/flake.nix
@@ -197,6 +197,7 @@
             inputs.pvv-calendar-bot.nixosModules.default
             inputs.minecraft-heatmap.nixosModules.default
             self.nixosModules.gickup
+            self.nixosModules.hugepages
             self.nixosModules.matrix-ooye
           ];
           overlays = [
diff --git a/hosts/bicep/services/postgresql/default.nix b/hosts/bicep/services/postgresql/default.nix
index d4e31b7..57b0470 100644
--- a/hosts/bicep/services/postgresql/default.nix
+++ b/hosts/bicep/services/postgresql/default.nix
@@ -1,6 +1,8 @@
 { config, lib, pkgs, values, ... }:
 let
   cfg = config.services.postgresql;
+
+  sharedBuffersMB = 8192;
 in
 {
   imports = [
@@ -29,7 +31,7 @@ in
       superuser_reserved_connections = 3;
 
       # Memory Settings
-      shared_buffers = "8192 MB";
+      shared_buffers = "${toString sharedBuffersMB} MB";
       work_mem = "32 MB";
       maintenance_work_mem = "420 MB";
       effective_cache_size = "22 GB";
@@ -93,6 +95,10 @@ in
     };
   };
 
+  boot.kernel.hugepages.reservations.postgresql = lib.mkIf cfg.enable (
+    builtins.ceil (sharedBuffersMB / config.boot.kernel.hugepages.size)
+  );
+
   systemd.tmpfiles.settings."10-postgresql"."/data/postgresql".d = lib.mkIf cfg.enable {
     user = config.systemd.services.postgresql.serviceConfig.User;
     group = config.systemd.services.postgresql.serviceConfig.Group;