On Fri, Mar 04, 2016 at 01:52:53AM +0000, Li, Liang Z wrote: > > I wonder if it would be possible to avoid the kernel changes by parsing > > /proc/self/pagemap - if that can be used to detect unmapped/zero mapped > > pages in the guest ram, would it achieve the same result? > > Only detect the unmapped/zero mapped pages is not enough. Consider the > situation like case 2, it can't achieve the same result. Your case 2 doesn't exist in the real world. If people could stop their main memory consumer in the guest prior to migration they wouldn't need live migration at all. I tend to think you can safely assume there's no free memory in the guest, so there's little point optimizing for it. OTOH it makes perfect sense optimizing for the unmapped memory that's made up, in particular, by the ballon, and consider inflating the balloon right before migration unless you already maintain it at the optimal size for other reasons (like e.g. a global resource manager optimizing the VM density). Roman. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
