From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH] [PATCH net-next] tun: fix multiqueue rx Date: Fri, 16 Nov 2018 15:10:21 -0500 Message-ID: <20181116150952-mutt-send-email-mst@kernel.org> References: <20181116041016.39852-1-matthew.cover@stackpath.com> <20181116070015.1759-1-matthew.cover@stackpath.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: davem@davemloft.net, jasowang@redhat.com, brouer@redhat.com, edumazet@google.com, sd@queasysnail.net, netdev@vger.kernel.org, matthew.cover@stackpath.com To: Matthew Cover Return-path: Received: from mx1.redhat.com ([209.132.183.28]:65369 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726879AbeKQGYO (ORCPT ); Sat, 17 Nov 2018 01:24:14 -0500 Content-Disposition: inline In-Reply-To: <20181116070015.1759-1-matthew.cover@stackpath.com> Sender: netdev-owner@vger.kernel.org List-ID: On Fri, Nov 16, 2018 at 12:00:15AM -0700, Matthew Cover wrote: > When writing packets to a descriptor associated with a combined queue, the > packets should end up on that queue. > > Before this change all packets written to any descriptor associated with a > tap interface end up on rx-0, even when the descriptor is associated with a > different queue. > > The rx traffic can be generated by either of the following. > 1. a simple tap program which spins up multiple queues and writes packets > to each of the file descriptors > 2. tx from a qemu vm with a tap multiqueue netdev > > The queue for rx traffic can be observed by either of the following (done > on the hypervisor in the qemu case). > 1. a simple netmap program which opens and reads from per-queue > descriptors > 2. configuring RPS and doing per-cpu captures with rxtxcpu > > Alternatively, if you printk() the return value of skb_get_rx_queue() just > before each instance of netif_receive_skb() in tun.c, you will get 65535 > for every skb. > > Calling skb_record_rx_queue() to set the rx queue to the queue_index fixes > the association between descriptor and rx queue. > > Signed-off-by: Matthew Cover Acked-by: Michael S. Tsirkin stable material? > --- > drivers/net/tun.c | 7 ++++++- > 1 file changed, 6 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/tun.c b/drivers/net/tun.c > index a65779c6d72f..ce8620f3ea5e 100644 > --- a/drivers/net/tun.c > +++ b/drivers/net/tun.c > @@ -1536,6 +1536,7 @@ static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile, > > if (!rx_batched || (!more && skb_queue_empty(queue))) { > local_bh_disable(); > + skb_record_rx_queue(skb, tfile->queue_index); > netif_receive_skb(skb); > local_bh_enable(); > return; > @@ -1555,8 +1556,11 @@ static void tun_rx_batched(struct tun_struct *tun, struct tun_file *tfile, > struct sk_buff *nskb; > > local_bh_disable(); > - while ((nskb = __skb_dequeue(&process_queue))) > + while ((nskb = __skb_dequeue(&process_queue))) { > + skb_record_rx_queue(nskb, tfile->queue_index); > netif_receive_skb(nskb); > + } > + skb_record_rx_queue(skb, tfile->queue_index); > netif_receive_skb(skb); > local_bh_enable(); > } > @@ -2452,6 +2456,7 @@ static int tun_xdp_one(struct tun_struct *tun, > !tfile->detached) > rxhash = __skb_get_hash_symmetric(skb); > > + skb_record_rx_queue(skb, tfile->queue_index); > netif_receive_skb(skb); > > stats = get_cpu_ptr(tun->pcpu_stats); > -- > 2.15.2 (Apple Git-101.1)