Enable threadsafe. Preload lib/

config/environments/production.rb

@@ -52,7 +52,7 @@ Gitlab::Application.configure do
   # config.action_mailer.raise_delivery_errors = false
   # Enable threaded mode
-  # config.threadsafe!
+  config.threadsafe!
   # Enable locale fallbacks for I18n (makes lookups for any locale fall back to
   # the I18n.default_locale when a translation can not be found)

config/initializers/2_app.rb

@@ -6,3 +6,8 @@ module Gitlab
     Settings
   end
 end
+
+#
+# Load all libs for threadsafety
+#
+Dir["#{Rails.root}/lib/**/*.rb"].each { |file| require file }