On Tue, 2008-05-06 at 15:46 -0400, Rik van Riel wrote: > On Tue, 06 May 2008 17:33:02 +0200 > Martin Schwidefsky <schwidefsky@xxxxxxxxxx> wrote: > > On Thu, 2008-03-13 at 16:57 +0000, Hugh Dickins wrote: > > > It's very encouraging to see Jeremy and Rusty weighing in. I hope > > > Zach will too, and I've added Andrea: their support would count a lot. > > > You have Nick on the list, good, I've added Christoph and Peter > > > (if you do resend, linux-mm might prove more useful than linux-kernel). > > > > > > With support from rival virtualizers, > > > I do think you've a good chance of getting in. > > > > Traffic on the guest page hinting patches died down again. Until another > > user shows up I guess that's it for the full version. > > I suspect one of the problems is that there are too many state transitions > to have it implemented with a low overhead on anything but S390, and even > there you need milicoded instructions to handle things. > > If the number of transitions can be reduced, page hinting could be useful > for KVM, too. Spot on Rik, if every transition becomes a hypercall (and a synchronous one at that), it isn't workable for us. If, on the other hand, you share the state bits between the guest and hypervisor, you need a giant (standalone) bit array for per-page state, which is neither convenient for Linux nor the hypervisor. I believe s390 has an 'instruction' to migrate the state bits into the hypervisor per-physical-page data without requiring a hypercall. Zach -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
