misc modules

modules/nixos/misc/default.nix

@@ -0,0 +1,6 @@
+{
+  imports = [
+    ./docs.nix
+    ./zram.nix
+  ];
+}

modules/nixos/misc/docs.nix

@@ -0,0 +1,19 @@
+{lib, ...}: let
+  inherit (lib.modules) mkForce;
+  inherit (lib.attrsets) mapAttrs;
+in {
+  # we don't need docs where we're going!
+  documentation = mapAttrs (_: mkForce) {
+    enable = false;
+    dev.enable = false;
+    doc.enable = false;
+    info.enable = false;
+    nixos.enable = false;
+    man = {
+      enable = false;
+      generateCaches = false;
+      man-db.enable = false;
+      mandoc.enable = false;
+    };
+  };
+}

modules/nixos/misc/zram.nix

@@ -0,0 +1,24 @@
+{
+  lib,
+  config,
+  ...
+}: let
+  inherit (lib.modules) mkIf;
+in {
+  # compress 3/4ths of ram to use as swap
+  # basically, get more memory per memory
+  zramSwap = {
+    enable = true;
+    algorithm = "zstd";
+    memoryPercent = 75; # defaults to 50
+  };
+
+  boot.kernel.sysctl = mkIf config.zramSwap.enable {
+    # zram is relatively cheap, prefer swap
+    "vm.swappiness" = 180;
+    "vm.watermark_boost_factor" = 0;
+    "vm.watermark_scale_factor" = 125;
+    # zram is in memory, no need to readahead
+    "vm.page-cluster" = 0;
+  };
+}