home-manager/firefox: Add memory control

Wrap Firefox with a privileged AutoConfig controller that unloads tabs under configurable MemAvailable hysteresis and exposes an on-demand reclaim command. Enable it by default for Linux GUI homes.
2026-08-13 12:24:45 +01:00
parent 0c6928f7ae
commit 82cbe67010
5 changed files with 457 additions and 3 deletions
@@ -0,0 +1,46 @@
+{
+  lib,
+  firefox-unwrapped,
+  wrapFirefox,
+  writeText,
+  writeScriptBin,
+  symlinkJoin,
+  python3,
+  lowAvailableMiB ? 2048,
+  highAvailableMiB ? 3072,
+  pollIntervalMs ? 1000,
+  minInactiveMs ? 300000,
+}:
+let
+  autoConfig = writeText "firefox-memory-control.js" ''
+    defaultPref("firefox.memoryControl.enabled", true);
+    defaultPref("firefox.memoryControl.lowAvailableMiB", ${toString lowAvailableMiB});
+    defaultPref("firefox.memoryControl.highAvailableMiB", ${toString highAvailableMiB});
+    defaultPref("firefox.memoryControl.pollIntervalMs", ${toString pollIntervalMs});
+    defaultPref("firefox.memoryControl.minInactiveMs", ${toString minInactiveMs});
+
+    ${builtins.readFile ./autoconfig.js}
+  '';
+
+  firefox = wrapFirefox firefox-unwrapped {
+    extraAutoConfig = ''
+      pref("general.config.sandbox_enabled", false);
+    '';
+    extraPrefsFiles = [ autoConfig ];
+  };
+
+  freeMemory = writeScriptBin "firefox-free-memory" ''
+    #!${python3}/bin/python3
+    ${builtins.readFile ./firefox-free-memory.py}
+  '';
+in
+symlinkJoin {
+  name = "firefox-memory-control-${firefox.version}";
+  paths = [ firefox freeMemory ];
+
+  meta = firefox.meta // {
+    description = "Firefox with memory-pressure tab unloading and an on-demand reclaim utility";
+    mainProgram = "firefox";
+    platforms = lib.platforms.linux;
+  };
+}