Add oobgc compatible with Ruby 2.1

lib/middleware/unicorn_oobgc.rb

@@ -33,6 +33,22 @@ module Middleware::UnicornOobgc
   # TUNE ME, for Discourse this number is good
   MIN_FREE_SLOTS = 50_000
 
+  # The oobgc implementation is far more efficient in 2.1
+  # as we have a bunch of profiling hooks to hook it
+  # use @tmm1s implementation
+  def use_gctools?
+    if @use_gctools.nil?
+      @use_gctools =
+        if RUBY_VERSION >= "2.1.0"
+          require "gctools/oobgc"
+          true
+        else
+          false
+        end
+    end
+    @use_gctools
+  end
+
   def verbose(msg=nil)
     @verbose ||= ENV["OOBGC_VERBOSE"] == "1" ? :true : :false
     if @verbose == :true
@@ -59,6 +75,12 @@ module Middleware::UnicornOobgc
   end
 
   def process_client(client)
+
+    if use_gctools?
+      GC::OOB.run
+      return
+    end
+
     stat = GC.stat
 
     @num_requests ||= 0