diff --git a/lib/gitlab/sidekiq_middleware/memory_killer.rb b/lib/gitlab/sidekiq_middleware/memory_killer.rb
index 2bfb7caefd99423ee7b1a3a76b44290188984cb1..b89ae2505c944b305456f7ddc38400aca0091bda 100644
--- a/lib/gitlab/sidekiq_middleware/memory_killer.rb
+++ b/lib/gitlab/sidekiq_middleware/memory_killer.rb
@@ -45,7 +45,7 @@ module Gitlab
       private
 
       def get_rss
-        output, status = Gitlab::Popen.popen(%W(ps -o rss= -p #{pid}))
+        output, status = Gitlab::Popen.popen(%W(ps -o rss= -p #{pid}), Rails.root.to_s)
         return 0 unless status.zero?
 
         output.to_i