Re: [PATCH] KVM simplified virtio balloon driver

Am Donnerstag, 17. Januar 2008 schrieb Rusty Russell:

Since the balloon requires Guest cooperation anyway, there seems
little reason to force it to tell the Host when it wants to reuse a
page.  It can simply fault it in.

Yes, thats what we do in the s390 cmm driver.

All in all the driver has similarities with cmm. I dont know, if we can 
consolidate some code.
Besides the hypervisor, we have a additional user interface: /proc/sys/vm/. 
The root user can specify the amount of pages in the balloon 
via /proc/sys/vm/cmm_pages. 

Another idea: Martin added an oom notifier to the cmm driver. Before the 
oom-killer kicks in cmm will try to free 256 pages. I think your virtio 
balloon driver should do the same - it seems to be the correct tradeoff. 

Christian