How to set per process swapiness for linux?

You can configure swappiness per cgroup:

http://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt

http://www.kernel.org/doc/Documentation/cgroup-v1/memory.txt

For an easier introduction to cgroups, with examples, see

https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Resource_Management_Guide/ch01.html