From: "Michael S. Tsirkin" <mst@redhat.com>
To: Hao Chen <chenh@yusur.tech>
Cc: Jason Wang <jasowang@redhat.com>,
Xuan Zhuo <xuanzhuo@linux.alibaba.com>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
"open list:VIRTIO CORE AND NET DRIVERS"
<virtualization@lists.linux-foundation.org>,
"open list:NETWORKING DRIVERS" <netdev@vger.kernel.org>,
open list <linux-kernel@vger.kernel.org>,
huangml@yusur.tech, zy@yusur.tech
Subject: Re: [PATCH] virtio_net: set default mtu to 1500 when 'Device maximum MTU' bigger than 1500
Date: Sun, 7 May 2023 01:59:35 -0400 [thread overview]
Message-ID: <20230507015819-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <20230506021529.396812-1-chenh@yusur.tech>
On Sat, May 06, 2023 at 10:15:29AM +0800, Hao Chen wrote:
> When VIRTIO_NET_F_MTU(3) Device maximum MTU reporting is supported.
> If offered by the device, device advises driver about the value of its
> maximum MTU. If negotiated, the driver uses mtu as the maximum
> MTU value. But there the driver also uses it as default mtu,
> some devices may have a maximum MTU greater than 1500, this may
> cause some large packages to be discarded, so I changed the MTU to a more
> general 1500 when 'Device maximum MTU' bigger than 1500.
>
> Signed-off-by: Hao Chen <chenh@yusur.tech>
I don't see why not use the maximum. Bigger packets = better
performance.
> ---
> drivers/net/virtio_net.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 8d8038538fc4..e71c7d1b5f29 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -4040,7 +4040,10 @@ static int virtnet_probe(struct virtio_device *vdev)
> goto free;
> }
>
> - dev->mtu = mtu;
> + if (mtu > 1500)
> + dev->mtu = 1500;
> + else
> + dev->mtu = mtu;
> dev->max_mtu = mtu;
> }
>
> --
> 2.27.0
prev parent reply other threads:[~2023-05-07 5:59 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-06 2:15 [PATCH] virtio_net: set default mtu to 1500 when 'Device maximum MTU' bigger than 1500 Hao Chen
2023-05-06 2:50 ` Xuan Zhuo
2023-05-06 8:56 ` Hao Chen
2023-05-07 8:58 ` Michael S. Tsirkin
2023-05-08 2:01 ` Xuan Zhuo
2023-05-08 6:15 ` Michael S. Tsirkin
2023-05-08 6:18 ` Xuan Zhuo
2023-05-08 6:43 ` Michael S. Tsirkin
2023-05-08 7:41 ` Xuan Zhuo
2023-05-08 10:30 ` Michael S. Tsirkin
2023-05-08 16:25 ` Stephen Hemminger
2023-05-08 18:10 ` Michael S. Tsirkin
2023-05-09 1:51 ` Xuan Zhuo
2023-05-07 9:31 ` David Woodhouse
2023-05-07 13:38 ` Michael S. Tsirkin
2023-05-07 5:59 ` Michael S. Tsirkin [this message]
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