[jbert]

> No it wouldn't. If a program has memory that it doesn't need and can live without it ought to just release it. Otherwise that is called a memory leak.

I disagree. A process could usefully cache the results of computation in RAM (e.g. a large lookup table). This RAM is useful to the process (will increase performance) but if it is discarded due to a spike in memory pressure it could be rebuilt.

> What happens when the kernel yanks a page of memory from über a running process?

There is a madvise() flag for this, MADV_DONTNEED - http://man7.org/linux/man-pages/man2/madvise.2.html

You get zero pages. Which is fine - you can detect that with a canary value and then you know you need to rebuild your cache.