Messages in this thread | | | Date | Thu, 6 Mar 2014 17:09:20 +0000 | From | Zoltan Kiss <> | Subject | Re: [PATCH] openvswitch: Orphan frags before sending to userspace via Netlink to avoid guest stall |
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Do you have any feedback on this? I'm also adding KVM list as they might be interested in this.
Zoli
On 28/02/14 19:16, Zoltan Kiss wrote: > The kernel datapath now switched to zerocopy Netlink messages, but that also > means that the pages on frags array are sent straight to userspace. If those > pages came outside the kernel, we have to swap them out with local copies. > > Signed-off-by: Zoltan Kiss <zoltan.kiss@citrix.com> > --- > net/openvswitch/datapath.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c > index 36f8872..ffb563c 100644 > --- a/net/openvswitch/datapath.c > +++ b/net/openvswitch/datapath.c > @@ -464,6 +464,12 @@ static int queue_userspace_packet(struct datapath *dp, struct sk_buff *skb, > } > nla->nla_len = nla_attr_size(skb->len); > > + if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) { > + err = -ENOMEM; > + skb_tx_error(skb); > + goto out; > + } > + > skb_zerocopy(user_skb, skb, skb->len, hlen); > > /* Pad OVS_PACKET_ATTR_PACKET if linear copy was performed */ >
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