Hi,
I’m not aware of any changes regarding HugeTLB memory in 5.6.21-rel.69.0 version but still I would suggest you to upgrade from Percona 5.6.21-rel.69.0.el5 to Percona 5.6.21-rel.71.0.el5. Because, it seems there were many bugs in rel.69, which was resolved in 71.0
[url]http://www.percona.com/blog/2014/11/24/percona-server-5-6-21-70-1-now-available/[/url]
You might be affected from any of them. So please try to upgrade newer version and let us know if you still facing the issue.