Messages in this thread | | | Date | Wed, 9 Mar 2016 20:04:39 +0300 | From | Roman Kagan <> | Subject | Re: [Qemu-devel] [RFC qemu 0/4] A PV solution for live migration optimization |
| |
On Wed, Mar 09, 2016 at 05:41:39PM +0200, Michael S. Tsirkin wrote: > On Wed, Mar 09, 2016 at 05:28:54PM +0300, Roman Kagan wrote: > > For (1) I've been trying to make a point that skipping clean pages is > > much more likely to result in noticable benefit than free pages only. > > I guess when you say clean you mean zero?
No I meant clean, i.e. those that could be evicted from RAM without causing I/O.
> Yea. In fact, one can zero out any number of pages > quickly by putting them in balloon and immediately > taking them out. > > Access will fault a zero page in, then COW kicks in.
I must be missing something obvious, but how is that different from inflating and then immediately deflating the balloon?
> We could have a new zero VQ (or some other option) > to pass these pages guest to host, but this only > works well if page size matches the host page size.
I'm afraid I don't yet understand what kind of pages that would be and how they are different from ballooned pages.
I still tend to think that ballooning is a sensible solution to the problem at hand; it's just the granularity that makes things slow and stands in the way.
Roman.
| |