netdev - Re: [PATCH v2] virtio_net: bulk free tx skbs

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Message-ID: <e0610506-ef97-21e4-bad4-e22bd077234c@redhat.com>
Date:   Fri, 18 Jan 2019 20:51:37 +0800
From:   Jason Wang <jasowang@...hat.com>
To:     "Michael S. Tsirkin" <mst@...hat.com>, linux-kernel@...r.kernel.org
Cc:     "David S. Miller" <davem@...emloft.net>,
        virtualization@...ts.linux-foundation.org, netdev@...r.kernel.org
Subject: Re: [PATCH v2] virtio_net: bulk free tx skbs


On 2019/1/18 下午12:20, Michael S. Tsirkin wrote:
> Use napi_consume_skb() to get bulk free.  Note that napi_consume_skb is
> safe to call in a non-napi context as long as the napi_budget flag is
> correct.
>
> Signed-off-by: Michael S. Tsirkin <mst@...hat.com>
> ---
>
> Changes from v1:
> 	rebase on master.
>
> lightly tested on developer's box.
>
>   drivers/net/virtio_net.c | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)


Acked-by: Jason Wang <jasowang@...hat.com>


>
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 023725086046..8fadd8eaf601 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -1330,7 +1330,7 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
>   	return stats.packets;
>   }
>   
> -static void free_old_xmit_skbs(struct send_queue *sq)
> +static void free_old_xmit_skbs(struct send_queue *sq, bool in_napi)
>   {
>   	struct sk_buff *skb;
>   	unsigned int len;
> @@ -1343,7 +1343,7 @@ static void free_old_xmit_skbs(struct send_queue *sq)
>   		bytes += skb->len;
>   		packets++;
>   
> -		dev_consume_skb_any(skb);
> +		napi_consume_skb(skb, in_napi);
>   	}
>   
>   	/* Avoid overhead when no packets have been processed
> @@ -1369,7 +1369,7 @@ static void virtnet_poll_cleantx(struct receive_queue *rq)
>   		return;
>   
>   	if (__netif_tx_trylock(txq)) {
> -		free_old_xmit_skbs(sq);
> +		free_old_xmit_skbs(sq, true);
>   		__netif_tx_unlock(txq);
>   	}
>   
> @@ -1445,7 +1445,7 @@ static int virtnet_poll_tx(struct napi_struct *napi, int budget)
>   	struct netdev_queue *txq = netdev_get_tx_queue(vi->dev, vq2txq(sq->vq));
>   
>   	__netif_tx_lock(txq, raw_smp_processor_id());
> -	free_old_xmit_skbs(sq);
> +	free_old_xmit_skbs(sq, true);
>   	__netif_tx_unlock(txq);
>   
>   	virtqueue_napi_complete(napi, sq->vq, 0);
> @@ -1514,7 +1514,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
>   	bool use_napi = sq->napi.weight;
>   
>   	/* Free up any pending old buffers before queueing new ones. */
> -	free_old_xmit_skbs(sq);
> +	free_old_xmit_skbs(sq, false);
>   
>   	if (use_napi && kick)
>   		virtqueue_enable_cb_delayed(sq->vq);
> @@ -1557,7 +1557,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
>   		if (!use_napi &&
>   		    unlikely(!virtqueue_enable_cb_delayed(sq->vq))) {
>   			/* More just got used, free them then recheck. */
> -			free_old_xmit_skbs(sq);
> +			free_old_xmit_skbs(sq, false);
>   			if (sq->vq->num_free >= 2+MAX_SKB_FRAGS) {
>   				netif_start_subqueue(dev, qnum);
>   				virtqueue_disable_cb(sq->vq);