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Date:   Tue, 31 Jul 2018 14:22:41 +0300
From:   "Michael S. Tsirkin" <mst@redhat.com>
To:     Jason Wang <jasowang@redhat.com>
Cc:     virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
        linux-kernel@vger.kernel.org,
        Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
Subject: Re: [PATCH net-next 2/2] virtio-net: get rid of unnecessary
 container of rq stats
Message-ID: <20180731142235-mutt-send-email-mst@kernel.org>
References: <1533030219-9904-1-git-send-email-jasowang@redhat.com>
 <1533030219-9904-2-git-send-email-jasowang@redhat.com>
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On Tue, Jul 31, 2018 at 05:43:39PM +0800, Jason Wang wrote:
> We don't maintain tx counters in rx stats any more. There's no need
> for an extra container of rq stats.
> 
> Cc: Toshiaki Makita <makita.toshiaki@lab.ntt.co.jp>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  drivers/net/virtio_net.c | 80 ++++++++++++++++++++++--------------------------
>  1 file changed, 36 insertions(+), 44 deletions(-)
> 
> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
> index 72d3f68..14f661c 100644
> --- a/drivers/net/virtio_net.c
> +++ b/drivers/net/virtio_net.c
> @@ -87,7 +87,8 @@ struct virtnet_sq_stats {
>  	u64 kicks;
>  };
>  
> -struct virtnet_rq_stat_items {
> +struct virtnet_rq_stats {
> +	struct u64_stats_sync syncp;
>  	u64 packets;
>  	u64 bytes;
>  	u64 drops;
> @@ -98,17 +99,8 @@ struct virtnet_rq_stat_items {
>  	u64 kicks;
>  };
>  
> -struct virtnet_rq_stats {
> -	struct u64_stats_sync syncp;
> -	struct virtnet_rq_stat_items items;
> -};
> -
> -struct virtnet_rx_stats {
> -	struct virtnet_rq_stat_items rx;
> -};
> -
>  #define VIRTNET_SQ_STAT(m)	offsetof(struct virtnet_sq_stats, m)
> -#define VIRTNET_RQ_STAT(m)	offsetof(struct virtnet_rq_stat_items, m)
> +#define VIRTNET_RQ_STAT(m)	offsetof(struct virtnet_rq_stats, m)
>  
>  static const struct virtnet_stat_desc virtnet_sq_stats_desc[] = {
>  	{ "packets",		VIRTNET_SQ_STAT(packets) },
> @@ -617,7 +609,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
>  				     void *buf, void *ctx,
>  				     unsigned int len,
>  				     unsigned int *xdp_xmit,
> -				     struct virtnet_rx_stats *stats)
> +				     struct virtnet_rq_stats *stats)
>  {
>  	struct sk_buff *skb;
>  	struct bpf_prog *xdp_prog;
> @@ -632,7 +624,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
>  	int err;
>  
>  	len -= vi->hdr_len;
> -	stats->rx.bytes += len;
> +	stats->bytes += len;
>  
>  	rcu_read_lock();
>  	xdp_prog = rcu_dereference(rq->xdp_prog);
> @@ -674,7 +666,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
>  		xdp.rxq = &rq->xdp_rxq;
>  		orig_data = xdp.data;
>  		act = bpf_prog_run_xdp(xdp_prog, &xdp);
> -		stats->rx.xdp_packets++;
> +		stats->xdp_packets++;
>  
>  		switch (act) {
>  		case XDP_PASS:
> @@ -683,7 +675,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
>  			len = xdp.data_end - xdp.data;
>  			break;
>  		case XDP_TX:
> -			stats->rx.xdp_tx++;
> +			stats->xdp_tx++;
>  			xdpf = convert_to_xdp_frame(&xdp);
>  			if (unlikely(!xdpf))
>  				goto err_xdp;
> @@ -696,7 +688,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
>  			rcu_read_unlock();
>  			goto xdp_xmit;
>  		case XDP_REDIRECT:
> -			stats->rx.xdp_redirects++;
> +			stats->xdp_redirects++;
>  			err = xdp_do_redirect(dev, &xdp, xdp_prog);
>  			if (err)
>  				goto err_xdp;
> @@ -730,8 +722,8 @@ static struct sk_buff *receive_small(struct net_device *dev,
>  
>  err_xdp:
>  	rcu_read_unlock();
> -	stats->rx.xdp_drops++;
> -	stats->rx.drops++;
> +	stats->xdp_drops++;
> +	stats->drops++;
>  	put_page(page);
>  xdp_xmit:
>  	return NULL;
> @@ -742,19 +734,19 @@ static struct sk_buff *receive_big(struct net_device *dev,
>  				   struct receive_queue *rq,
>  				   void *buf,
>  				   unsigned int len,
> -				   struct virtnet_rx_stats *stats)
> +				   struct virtnet_rq_stats *stats)
>  {
>  	struct page *page = buf;
>  	struct sk_buff *skb = page_to_skb(vi, rq, page, 0, len, PAGE_SIZE);
>  
> -	stats->rx.bytes += len - vi->hdr_len;
> +	stats->bytes += len - vi->hdr_len;
>  	if (unlikely(!skb))
>  		goto err;
>  
>  	return skb;
>  
>  err:
> -	stats->rx.drops++;
> +	stats->drops++;
>  	give_pages(rq, page);
>  	return NULL;
>  }
> @@ -766,7 +758,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  					 void *ctx,
>  					 unsigned int len,
>  					 unsigned int *xdp_xmit,
> -					 struct virtnet_rx_stats *stats)
> +					 struct virtnet_rq_stats *stats)
>  {
>  	struct virtio_net_hdr_mrg_rxbuf *hdr = buf;
>  	u16 num_buf = virtio16_to_cpu(vi->vdev, hdr->num_buffers);
> @@ -779,7 +771,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  	int err;
>  
>  	head_skb = NULL;
> -	stats->rx.bytes += len - vi->hdr_len;
> +	stats->bytes += len - vi->hdr_len;
>  
>  	rcu_read_lock();
>  	xdp_prog = rcu_dereference(rq->xdp_prog);
> @@ -828,7 +820,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  		xdp.rxq = &rq->xdp_rxq;
>  
>  		act = bpf_prog_run_xdp(xdp_prog, &xdp);
> -		stats->rx.xdp_packets++;
> +		stats->xdp_packets++;
>  
>  		switch (act) {
>  		case XDP_PASS:
> @@ -853,7 +845,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  			}
>  			break;
>  		case XDP_TX:
> -			stats->rx.xdp_tx++;
> +			stats->xdp_tx++;
>  			xdpf = convert_to_xdp_frame(&xdp);
>  			if (unlikely(!xdpf))
>  				goto err_xdp;
> @@ -870,7 +862,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  			rcu_read_unlock();
>  			goto xdp_xmit;
>  		case XDP_REDIRECT:
> -			stats->rx.xdp_redirects++;
> +			stats->xdp_redirects++;
>  			err = xdp_do_redirect(dev, &xdp, xdp_prog);
>  			if (err) {
>  				if (unlikely(xdp_page != page))
> @@ -920,7 +912,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  			goto err_buf;
>  		}
>  
> -		stats->rx.bytes += len;
> +		stats->bytes += len;
>  		page = virt_to_head_page(buf);
>  
>  		truesize = mergeable_ctx_to_truesize(ctx);
> @@ -966,7 +958,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  
>  err_xdp:
>  	rcu_read_unlock();
> -	stats->rx.xdp_drops++;
> +	stats->xdp_drops++;
>  err_skb:
>  	put_page(page);
>  	while (num_buf-- > 1) {
> @@ -977,12 +969,12 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  			dev->stats.rx_length_errors++;
>  			break;
>  		}
> -		stats->rx.bytes += len;
> +		stats->bytes += len;
>  		page = virt_to_head_page(buf);
>  		put_page(page);
>  	}
>  err_buf:
> -	stats->rx.drops++;
> +	stats->drops++;
>  	dev_kfree_skb(head_skb);
>  xdp_xmit:
>  	return NULL;
> @@ -991,7 +983,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
>  static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
>  			void *buf, unsigned int len, void **ctx,
>  			unsigned int *xdp_xmit,
> -			struct virtnet_rx_stats *stats)
> +			struct virtnet_rq_stats *stats)
>  {
>  	struct net_device *dev = vi->dev;
>  	struct sk_buff *skb;
> @@ -1212,7 +1204,7 @@ static bool try_fill_recv(struct virtnet_info *vi, struct receive_queue *rq,
>  	} while (rq->vq->num_free);
>  	if (virtqueue_kick_prepare(rq->vq) && virtqueue_notify(rq->vq)) {
>  		u64_stats_update_begin(&rq->stats.syncp);
> -		rq->stats.items.kicks++;
> +		rq->stats.kicks++;
>  		u64_stats_update_end(&rq->stats.syncp);
>  	}
>  
> @@ -1290,7 +1282,7 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
>  			   unsigned int *xdp_xmit)
>  {
>  	struct virtnet_info *vi = rq->vq->vdev->priv;
> -	struct virtnet_rx_stats stats = {};
> +	struct virtnet_rq_stats stats = {};
>  	unsigned int len;
>  	void *buf;
>  	int i;
> @@ -1298,16 +1290,16 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
>  	if (!vi->big_packets || vi->mergeable_rx_bufs) {
>  		void *ctx;
>  
> -		while (stats.rx.packets < budget &&
> +		while (stats.packets < budget &&
>  		       (buf = virtqueue_get_buf_ctx(rq->vq, &len, &ctx))) {
>  			receive_buf(vi, rq, buf, len, ctx, xdp_xmit, &stats);
> -			stats.rx.packets++;
> +			stats.packets++;
>  		}
>  	} else {
> -		while (stats.rx.packets < budget &&
> +		while (stats.packets < budget &&
>  		       (buf = virtqueue_get_buf(rq->vq, &len)) != NULL) {
>  			receive_buf(vi, rq, buf, len, NULL, xdp_xmit, &stats);
> -			stats.rx.packets++;
> +			stats.packets++;
>  		}
>  	}
>  
> @@ -1321,12 +1313,12 @@ static int virtnet_receive(struct receive_queue *rq, int budget,
>  		size_t offset = virtnet_rq_stats_desc[i].offset;
>  		u64 *item;
>  
> -		item = (u64 *)((u8 *)&rq->stats.items + offset);
> -		*item += *(u64 *)((u8 *)&stats.rx + offset);
> +		item = (u64 *)((u8 *)&rq->stats + offset);
> +		*item += *(u64 *)((u8 *)&stats + offset);
>  	}
>  	u64_stats_update_end(&rq->stats.syncp);
>  
> -	return stats.rx.packets;
> +	return stats.packets;
>  }
>  
>  static void free_old_xmit_skbs(struct send_queue *sq)
> @@ -1686,9 +1678,9 @@ static void virtnet_stats(struct net_device *dev,
>  
>  		do {
>  			start = u64_stats_fetch_begin_irq(&rq->stats.syncp);
> -			rpackets = rq->stats.items.packets;
> -			rbytes   = rq->stats.items.bytes;
> -			rdrops   = rq->stats.items.drops;
> +			rpackets = rq->stats.packets;
> +			rbytes   = rq->stats.bytes;
> +			rdrops   = rq->stats.drops;
>  		} while (u64_stats_fetch_retry_irq(&rq->stats.syncp, start));
>  
>  		tot->rx_packets += rpackets;
> @@ -2078,7 +2070,7 @@ static void virtnet_get_ethtool_stats(struct net_device *dev,
>  	for (i = 0; i < vi->curr_queue_pairs; i++) {
>  		struct receive_queue *rq = &vi->rq[i];
>  
> -		stats_base = (u8 *)&rq->stats.items;
> +		stats_base = (u8 *)&rq->stats;
>  		do {
>  			start = u64_stats_fetch_begin_irq(&rq->stats.syncp);
>  			for (j = 0; j < VIRTNET_RQ_STATS_LEN; j++) {
> -- 
> 2.7.4