Deallocating memory pages

[Patrick Hemmer]

There's a mailing list thread from a few years ago which proposed using
madvise(MADV_DONTNEED) to let the kernel know about pages that it can
reclaim:
http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2013-January/005664.html
One of the last posts to the thread commented:
> I'll get feedback from the other GC guys and let you know what we
> want to do.

What ever came of this?

Such a feature would be highly beneficial when running multiple JVM
based applications on a host, and said applications are occasionally
"spikey" in their heap usage. Given the advent of container technologies
(docker, lxc, etc), this becomes even more important, as you might have
a wide variety of JVM apps on a single host, which don't all need the
same amount of memory at the same time. This feature would prevent the
kernel from having to swap out pages, potentially impacting system
performance.

-Patrick