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Subject: Re: [PATCH net-next 1/2] virtio-net: correctly update XDP_TX counters
References: <1533030219-9904-1-git-send-email-jasowang@redhat.com>
From:   Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Message-ID: <2cdb8081-90a8-3a87-b6a6-4395825594a1@lab.ntt.co.jp>
Date:   Tue, 31 Jul 2018 18:57:21 +0900
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To:     Jason Wang <jasowang@redhat.com>
Cc:     mst@redhat.com, virtualization@lists.linux-foundation.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
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On 2018/07/31 18:43, Jason Wang wrote:
> Commit 5b8f3c8d30a6 ("virtio_net: Add XDP related stats") tries to
> count TX XDP stats in virtnet_receive(). This will cause several
> issues:
> 
> - virtnet_xdp_sq() was called without checking whether or not XDP is
>   set. This may cause out of bound access when there's no enough txq
>   for XDP.
> - Stats were updated even if there's no XDP/XDP_TX.>
> Fixing this by reusing virtnet_xdp_xmit() for XDP_TX which can counts
> TX XDP counter itself and remove the unnecessary tx stats embedded in
> rx stats.

Thanks for fixing this.
I wanted to avoid calling u64_stats_update_begin() (i.e. smp_wmb() in 32
bit systems) for every packet. So I'd like to keep sq stats in
virtnet_rx_stats.

-- 
Toshiaki Makita