try setting a higher swappiness, take other val for mem calculation

script/ci/before.sh

@@ -14,9 +14,10 @@ sh -e /etc/init.d/xvfb start
 
 # setup swapfile
 echo "creating a swapfile"
-sudo dd if=/dev/zero of=swapfile bs=1M count=128
+sudo dd if=/dev/zero of=swapfile bs=1M count=96
 sudo mkswap swapfile
 sudo swapon swapfile
+sudo sysctl vm.swappiness=100
 
 # Create a database.yml for the right database
 echo "Setting up database.yml for $DB"

spec/support/deferred_garbage_collection.rb

@@ -14,7 +14,7 @@ class DeferredGarbageCollection
   def self.memory_threshold
     @mem = %x(free 2>/dev/null).to_s.split(" ")
     return nil if @mem.empty?
-    @mem[8].to_i / (@mem[7].to_i/100)
+    @mem[15].to_i / (@mem[7].to_i/100)
   end
 
   def self.reconsider