[RFC 0/8]KVM: swap out guest pages

[Shaohua Li <shaohua.li@intel.com>]

This patch series make kvm guest pages be able to be swapped out and
dynamically allocated. Without it, all guest memory is allocated at
guest start time.

patches are against latest git, and you need first patch Avi's kvm-sch
integration patch
(http://sourceforge.net/mailarchive/forum.php?thread_name=11841693332609-git-send-email-avi%40qumranet.com&forum_name=kvm-devel ).

Patch is quite stable in my test. With the patch, I can run a 256M
memory guest in a 300M memory host. If guest is idle, the memory it used
can be less than 10M. I did a simple performance test (measure kernel
build time in guest), if there is few swap, the performance w/wo the
patch difference isn't significent. If you have better measurement
approach, please let me try.

Unresolved issue:
1. swapoff doesn't work, we need a hook.
2. SMP guest might not work, as kvm doesn't support smp till now.
3. better algorithm to select swaped out guest pages according to
guest's memory usage.
Maybe more.

Any suggests and comments are appreciated.

Thanks,
Shaohua