From e1a6c85c2ba53933bfe5b6a86b9031cc28e4f9e1 Mon Sep 17 00:00:00 2001
From: Martino Fontana <tinozzo123@tutanota.com>
Date: Wed, 21 Jun 2023 19:23:08 +0200
Subject: [PATCH] nixos/sysctl: raise default vm.max_map_count to 1048576

---
 nixos/modules/config/malloc.nix                          | 1 -
 nixos/modules/config/sysctl.nix                          | 3 +++
 nixos/modules/virtualisation/lxd.nix                     | 2 +-
 pkgs/applications/networking/browsers/firefox/common.nix | 1 +
 4 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/config/malloc.nix b/nixos/modules/config/malloc.nix
index ae0661f472f6..043f78c8214e 100644
--- a/nixos/modules/config/malloc.nix
+++ b/nixos/modules/config/malloc.nix
@@ -97,7 +97,6 @@ in
   };
 
   config = mkIf (cfg.provider != "libc") {
-    boot.kernel.sysctl."vm.max_map_count" = mkIf (cfg.provider == "graphene-hardened") (mkDefault 1048576);
     environment.etc."ld-nix.so.preload".text = ''
       ${providerLibPath}
     '';
diff --git a/nixos/modules/config/sysctl.nix b/nixos/modules/config/sysctl.nix
index 4346c88f7688..0bc7ab9667f9 100644
--- a/nixos/modules/config/sysctl.nix
+++ b/nixos/modules/config/sysctl.nix
@@ -72,5 +72,8 @@ in
     # Disable YAMA by default to allow easy debugging.
     boot.kernel.sysctl."kernel.yama.ptrace_scope" = mkDefault 0;
 
+    # Improve compatibility with applications that allocate
+    # a lot of memory, like modern games
+    boot.kernel.sysctl."vm.max_map_count" = mkDefault 1048576;
   };
 }
diff --git a/nixos/modules/virtualisation/lxd.nix b/nixos/modules/virtualisation/lxd.nix
index c06716e5eb60..738382ef41a5 100644
--- a/nixos/modules/virtualisation/lxd.nix
+++ b/nixos/modules/virtualisation/lxd.nix
@@ -177,7 +177,7 @@ in {
       "fs.inotify.max_queued_events" = 1048576;
       "fs.inotify.max_user_instances" = 1048576;
       "fs.inotify.max_user_watches" = 1048576;
-      "vm.max_map_count" = 262144;
+      "vm.max_map_count" = 262144; # TODO: Default vm.max_map_count has been increased system-wide
       "kernel.dmesg_restrict" = 1;
       "net.ipv4.neigh.default.gc_thresh3" = 8192;
       "net.ipv6.neigh.default.gc_thresh3" = 8192;
diff --git a/pkgs/applications/networking/browsers/firefox/common.nix b/pkgs/applications/networking/browsers/firefox/common.nix
index ae7223ec721b..0a578520ae26 100644
--- a/pkgs/applications/networking/browsers/firefox/common.nix
+++ b/pkgs/applications/networking/browsers/firefox/common.nix
@@ -357,6 +357,7 @@ buildStdenv.mkDerivation ({
     export MOZILLA_OFFICIAL=1
   '' + lib.optionalString stdenv.hostPlatform.isMusl ''
     # linking firefox hits the vm.max_map_count kernel limit with the default musl allocator
+    # TODO: Default vm.max_map_count has been increased, retest without this
     export LD_PRELOAD=${mimalloc}/lib/libmimalloc.so
   '';