NUMA CentOS 5.x vs CentOS 6.x differences

Hello All.

We are in a process of migration CentOS 5.x -> CenstOS 6.x, we are using Percona 5.6.26 release and I found interesting behaviour:

CentOS 6.x based systems are swapping even with 4 GB buffer pool size and 32GB memory =(.

Most of CentOS 5.x based systems are not using SWAP at all.

I tried to dig into this problem and found some articles about NUMA memory allocation, but: CentOS 5.x and CentOS 6.x are NUMA enabled systems. What is the difference?

I have not tried to fix at this moment and as I understood [B]

Could someone explain the difference of SWAP policy in CentOS 5/6 + Percona?

CO5: 2.6.18-348.2.1.el5
CO6: 2.6.32-431.20.3.el6.x86_64

/proc/sys/vm/swappiness is 60 by default.