@dhiraj26683 Sorry for late reply, I'm interested if you solve this issue?

I have similar issue on one node in cluster, the other working well.

When memory issue happened last time I moved all VMs on 'healty' node and on problematic node I applied:

# free && sync && echo 3 > /proc/sys/vm/drop_caches && free 

After few seconds I was prompted with login (all the time server was responsive so I think it is not restarted).

I know that doesn't solve problem of not releasing cache, but I didn't have to restart server, at least - maybe

So if you have something better, please let me know!