From mboxrd@z Thu Jan 1 00:00:00 1970 From: Qin Chuanyu Subject: Re: [PATCH] bridge: orphan frags on local receive Date: Mon, 24 Feb 2014 21:52:11 +0800 Message-ID: <530B4E8B.5050007@huawei.com> References: <530B4534.3000106@huawei.com> <20140224132926.GF8981@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Cc: , KVM list , To: "Michael S. Tsirkin" Return-path: In-Reply-To: <20140224132926.GF8981@redhat.com> Sender: netdev-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 2014/2/24 21:29, Michael S. Tsirkin wrote: > On Mon, Feb 24, 2014 at 09:12:20PM +0800, Qin Chuanyu wrote: >> with vhost tx zero_copy, guest nic might get hang when host reserving >> skb in socket queue delivered by guest, the case has been solved in >> tun, it also been needed by bridge. This could easily happened when a >> LAST_ACK state tcp occuring between guest and host. >> >> Signed-off-by: Chuanyu Qin > > Do you actually observe guest hang? > yes, guest nic could not xmit any more until the skb holded by host has been freed, the mainly reason is that though virtio-net could use vring desc out of order, but ubufs is been used by vhost in order. so only one skb could cause guest nic hang. > I would expect orphan frags in > __netif_receive_skb_core to be enough. > yes, it would be better. I would deliver another patch soon. > >> --- >> net/bridge/br_input.c | 3 +++ >> 1 files changed, 3 insertions(+), 0 deletions(-) >> >> diff --git a/net/bridge/br_input.c b/net/bridge/br_input.c >> index 28d5446..744e27a 100644 >> --- a/net/bridge/br_input.c >> +++ b/net/bridge/br_input.c >> @@ -117,6 +117,8 @@ int br_handle_frame_finish(struct sk_buff *skb) >> br->dev->stats.multicast++; >> } else if ((dst = __br_fdb_get(br, dest, vid)) && >> dst->is_local) { >> + if (unlikely(skb_orphan_frags(skb, GFP_ATOMIC))) >> + goto drop; >> skb2 = skb; >> /* Do not forward the packet since it's local. */ >> skb = NULL; >> @@ -136,6 +138,7 @@ int br_handle_frame_finish(struct sk_buff *skb) >> out: >> return 0; >> drop: >> + skb_tx_error(skb); >> kfree_skb(skb); >> goto out; >> } >> -- >> 1.7.3.1.msysgit.0 > >