Swap space becomes critically low in the system

Hi,

We are facing a situation where the swap space space  is critically low in the system, there is just 10 % available swap space in the system

And we can't see the swap space being released to the OS .

This is one of the  Application servers we have for R3 system.

SAP environment:

SAP Netweaver 7.01

LINUX RHEL

Oracle 11g

$free -m //outut

As you can see we have 64G physical memory allocated to this application server whereas the configured swap space is around 20G.

This Linux box houses two application server one for R3 and the other for CRM.

Would appreciate if you can tell me what should be done to release the swap space as above shows that 18 gig of 20 is being used right now.

Regards,

Rakesh