On Wed, Sep 15, 2010 at 05:04:12PM +0200, Michael S. Tsirkin wrote: > On Wed, Sep 15, 2010 at 07:52:34AM -0700, Shirley Ma wrote: > > On Wed, 2010-09-15 at 12:10 +0200, Michael S. Tsirkin wrote: > > > Another issue is that macvtap can be bound to almost > > > anything, including e.g. a tap device or a bridge, > > > which might hang on to skb fragments for unlimited time. > > > Zero copy TX won't easily work there. > > > I can imagine either somehow triggering a data copy after the > > > fact (hard), or detecting such devices and avoiding > > > zero copy (unfortunate for guest to guest, and drivers > > > will need tuning). > > > > So far macvtap zero copy patch is limited to lower devices supports high > > memory DMA, it doesn't apply to a tap device or a bridge. > > Okay. What about macvtap in bridge mode? In fact, I rechecked: both bridge and loopback have NETIF_F_HIGHDMA set. So maybe we should check NETIF_F_NETNS_LOCAL ... macvtap in bridged mode is interesting as well. > > > > Don't you think once I address vhost_add_used_and_signal update > > > > issue, it is a simple and complete patch for macvtap TX zero copy? > > > > > > > > Thanks > > > > Shirley > > > > > > I like the fact that the patch is simple. Unfortunately > > > I suspect it'll stop being simple by the time it's complete :) > > > > I can make a try. :) > > > > Thanks > > Shirley -- 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
