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. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>