search for: fileballoon

...anything open >> for interpretation. > > I'm fine with adding more clarifications but I don't yet see why > do we need a new bit. There are three cases: 1) the drivers is not able to tell the host first (or never tell the host at all), like the Windows driver or the Google fileballoon driver. If the host always wants to be told first (e.g. a hypothetical virtio-balloon running on Xen) it should somehow prevent these drivers from running. 2) the driver will always tell the host first, like the Linux driver. The host can trust the guest to do the right thing. 3) the driver want...

...n. > > > > I'm fine with adding more clarifications but I don't yet see why > > do we need a new bit. > > There are three cases: > > 1) the drivers is not able to tell the host first (or never tell the > host at all), like the Windows driver or the Google fileballoon driver. > If the host always wants to be told first (e.g. a hypothetical > virtio-balloon running on Xen) it should somehow prevent these drivers > from running. I don't think hosts that always want to be told first can exist. Handling guests that don't tell first is super easy -...

On Tue, May 28, 2013 at 07:40:18PM +0200, Paolo Bonzini wrote: > The original idea of the VIRTIO_BALLOON_F_MUST_TELL_HOST feature was to > let drivers skip usage of the deflate queue when leaking the balloon > ("silent deflation"). Guests may benefit from silent deflate by > aggressively inflating the balloon; they know that they will be able to > use ballooned pages

Il 27/05/2013 19:02, Michael S. Tsirkin ha scritto: >>> So if we don't want to require all guests to tell host >>> first, all we need to do is admit it's not a bug. >> >> I think we want the possibility for the host to require that. > > But why? TELL_HOST makes some optimizations possible, but if > guest won't cooperate, balloon is useless

...t; I'm fine with adding more clarifications but I don't yet see why >>> do we need a new bit. >> >> There are three cases: >> >> 1) the drivers is not able to tell the host first (or never tell the >> host at all), like the Windows driver or the Google fileballoon driver. >> If the host always wants to be told first (e.g. a hypothetical >> virtio-balloon running on Xen) it should somehow prevent these drivers >> from running. > > I don't think hosts that always want to be told first can exist. > Handling guests that don't...

...showing how this new feature improves > performance? > We are able to batch quite a lot of pages in a single deflate > request - is the overhead measureable in practice? It's not only about better times, but also about better algorithms. I started writing this after seeing the Google fileballoon driver. For that implementation, the deflateq cannot be used at all. Paolo

...re clarifications but I don't yet see why > >>> do we need a new bit. > >> > >> There are three cases: > >> > >> 1) the drivers is not able to tell the host first (or never tell the > >> host at all), like the Windows driver or the Google fileballoon driver. > >> If the host always wants to be told first (e.g. a hypothetical > >> virtio-balloon running on Xen) it should somehow prevent these drivers > >> from running. > > > > I don't think hosts that always want to be told first can exist. > >...