Allow for balloon memory compaction/migration

configname: CONFIG_BALLOON_COMPACTION

Linux Kernel Configuration
└─>Memory Management options
└─>Allow for balloon memory compaction/migration
In linux kernel since version 3.1 (release Date: 2011-10-24)  
Memory fragmentation introduced by ballooning might reduce
significantly the number of 2MB contiguous memory blocks that can be
used within a guest, thus imposing performance penalties associated
with the reduced number of transparent huge pages that could be used
by the guest workload. Allowing the compaction & migration for memory
pages enlisted as being part of memory balloon devices avoids the
scenario aforementioned and helps improving memory defragmentation.