On Wed, 2010-09-29 at 10:16 +0200, Michael S. Tsirkin wrote: > > I compared several approaches for addressing the issue being raised > here > > on how/when to update vhost_add_used_and_signal. The simple approach > I > > have found is: > > > > 1. Adding completion field in struct virtqueue; > > 2. when it is a zero copy packet, put vhost thread wait for > completion > > to update vhost_add_used_and_signal; > > 3. passing vq from vhost to macvtap as skb destruct_arg; > > 4. when skb is freed for the last reference, signal vq completion > > The test results show same performance as the original patch. How do > you > > think? If it sounds good to you. I will resubmit this reversion > patch. > > The patch still keeps as simple as it was before. :) > > > > Thanks > > Shirley > > If you look at dev_hard_start_xmit you will see a call > to skb_orphan_try which often calls the skb destructor. > So I suspect this is almost equivalent to your original patch, > and has the same correctness issue. If I didn't address this, then vhost net will wait for ever with wait for completion :)) 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
