use gem

Gemfile

@@ -29,6 +29,7 @@ gem 'rmagick', :require => "RMagick"
 gem 'daemons'
 gem 'net-ssh'
 gem 'net-sftp'
+gem 'sys-proctable', :require => "sys/proctable"
 
 group :development do
   gem 'newrelic_rpm'

Gemfile.lock

@@ -159,6 +159,7 @@ GEM
     super_exception_notifier (3.0.13)
       actionmailer
       rake
+    sys-proctable (0.9.2)
     therubyracer (0.11.3)
       libv8 (~> 3.11.8.12)
       ref
@@ -207,6 +208,7 @@ DEPENDENCIES
   simple_form
   simplecov
   super_exception_notifier
+  sys-proctable
   therubyracer
   uglifier (>= 1.0.3)
   whenever

app/logical/memorylogic.rb

@@ -4,6 +4,11 @@ module Memorylogic
   end
 
   def self.memory_usage
-    number_to_human_size(`ps -o rss= -p #{Process.pid}`.to_i * 1.kilobyte)
+    ps = Sys::ProcTable.ps(Process.pid)
+    if ps.respond_to?(:rss)
+      number_to_human_size(ps.rss.to_i * 1.kilobyte)
+    else
+      0
+    end
   end
 end