From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Cover Subject: [PATCH] [PATCH net-next] tun: fix multiqueue rx Date: Thu, 15 Nov 2018 21:10:16 -0700 Message-ID: <20181116041016.39852-1-matthew.cover@stackpath.com> To: davem@davemloft.net, jasowang@redhat.com, brouer@redhat.com, mst@redhat.com, edumazet@google.com, sd@queasysnail.net, netdev@vger.kernel.org, matthew.cover@stackpath.com Return-path: Received: from mail-ot1-f66.google.com ([209.85.210.66]:33014 "EHLO mail-ot1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727142AbeKPOVY (ORCPT ); Fri, 16 Nov 2018 09:21:24 -0500 Received: by mail-ot1-f66.google.com with SMTP id i20so13762226otl.0 for ; Thu, 15 Nov 2018 20:10:41 -0800 (PST) Sender: netdev-owner@vger.kernel.org List-ID: 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 --- drivers/net/tun.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/net/tun.c b/drivers/net/tun.c index a65779c6d72f..4e306ff3501c 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(); } -- 2.15.2 (Apple Git-101.1)