>Does C/C++ provide any API / system call that enables user to force the application to transfer some its physical pages to swap disk ? If so, is it also possible to obtain the least used page using some API ?

I don't think such a system call exists. There might be some mechanisms that may cause your memory to be swapped out as a side effect, but I doubt you have much control over which page gets swapped.

> AFAIK, linux kernel is supposed to do this as part of memory management. I want to know if the kernel also exposes some API to enable users to control their application's memory management. I have many applications running at a time that cause too much memory consumption. I believe that experimenting with memory management can help.

I really don't think this kind of management can, or should, be done from user-space. If you have too much memory consumption, try to increase system memory or optimize your applications.