Re: [PATCH] kni: add chained mbufs support

["Zhang, Helin" <helin.zhang@intel.com>]

Have you tested with it?
I think we need to test it in a longer time, e.g. 1 hour
My commetns inlined.

Thanks,
Helin

> -----Original Message-----
> From: Yigit, Ferruh
> Sent: Tuesday, April 26, 2016 12:11 AM
> To: dev@dpdk.org
> Cc: Zhang, Helin; Yigit, Ferruh
> Subject: [PATCH] kni: add chained mbufs support
> 
> rx_q fifo may have chained mbufs, merge them into single skb before
> handing to the network stack.
> 
> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
> ---
>  .../linuxapp/eal/include/exec-env/rte_kni_common.h |  4 +-
>  lib/librte_eal/linuxapp/kni/kni_net.c              | 83 ++++++++++++++++------
>  2 files changed, 64 insertions(+), 23 deletions(-)
> 
> diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
> b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
> index 7e5e598..2acdfd9 100644
> --- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
> +++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_kni_common.h
> @@ -113,7 +113,9 @@ struct rte_kni_mbuf {
>  	void *buf_addr __attribute__((__aligned__(RTE_CACHE_LINE_SIZE)));
>  	char pad0[10];
>  	uint16_t data_off;      /**< Start address of data in segment buffer.
> */
> -	char pad1[4];
> +	char pad1[2];
> +	uint8_t nb_segs;        /**< Number of segments. */
> +	char pad4[1];
>  	uint64_t ol_flags;      /**< Offload features. */
>  	char pad2[4];
>  	uint32_t pkt_len;       /**< Total pkt len: sum of all segment data_len.
> */
> diff --git a/lib/librte_eal/linuxapp/kni/kni_net.c
> b/lib/librte_eal/linuxapp/kni/kni_net.c
> index cfa8339..570de71 100644
> --- a/lib/librte_eal/linuxapp/kni/kni_net.c
> +++ b/lib/librte_eal/linuxapp/kni/kni_net.c
> @@ -156,7 +156,8 @@ kni_net_rx_normal(struct kni_dev *kni)
>  	/* Transfer received packets to netif */
>  	for (i = 0; i < num_rx; i++) {
>  		kva = (void *)va[i] - kni->mbuf_va + kni->mbuf_kva;
> -		len = kva->data_len;
> +		len = kva->pkt_len;
> +
>  		data_kva = kva->buf_addr + kva->data_off - kni->mbuf_va
>  				+ kni->mbuf_kva;
> 
> @@ -165,22 +166,41 @@ kni_net_rx_normal(struct kni_dev *kni)
>  			KNI_ERR("Out of mem, dropping pkts\n");
>  			/* Update statistics */
>  			kni->stats.rx_dropped++;
> +			continue;
>  		}
> -		else {
> -			/* Align IP on 16B boundary */
> -			skb_reserve(skb, 2);
> +
> +		/* Align IP on 16B boundary */
> +		skb_reserve(skb, 2);
> +
> +		if (kva->nb_segs == 0) {
I guess it should compare nb_segs with 1, but not 0. Am I wrong?

>  			memcpy(skb_put(skb, len), data_kva, len);
> -			skb->dev = dev;
> -			skb->protocol = eth_type_trans(skb, dev);
> -			skb->ip_summed = CHECKSUM_UNNECESSARY;
> +		} else {
> +			int nb_segs;
> +			int kva_nb_segs = kva->nb_segs;
> 
> -			/* Call netif interface */
> -			netif_rx_ni(skb);
> +			for (nb_segs = 0; nb_segs < kva_nb_segs; nb_segs++)
Kva_nb_segs might not needed at all, use kva->nb_segs directly?

> {
> +				memcpy(skb_put(skb, kva->data_len),
> +					data_kva, kva->data_len);
> 
> -			/* Update statistics */
> -			kni->stats.rx_bytes += len;
> -			kni->stats.rx_packets++;
> +				if (!kva->next)
> +					break;
> +
> +				kva = kva->next - kni->mbuf_va + kni-
> >mbuf_kva;
> +				data_kva = kva->buf_addr + kva->data_off
> +					- kni->mbuf_va + kni->mbuf_kva;
> +			}
>  		}
> +
> +		skb->dev = dev;
> +		skb->protocol = eth_type_trans(skb, dev);
> +		skb->ip_summed = CHECKSUM_UNNECESSARY;
> +
> +		/* Call netif interface */
> +		netif_rx_ni(skb);
> +
> +		/* Update statistics */
> +		kni->stats.rx_bytes += len;
> +		kni->stats.rx_packets++;
>  	}
> 
>  	/* Burst enqueue mbufs into free_q */
> @@ -317,7 +337,7 @@ kni_net_rx_lo_fifo_skb(struct kni_dev *kni)
>  	/* Copy mbufs to sk buffer and then call tx interface */
>  	for (i = 0; i < num; i++) {
>  		kva = (void *)va[i] - kni->mbuf_va + kni->mbuf_kva;
> -		len = kva->data_len;
> +		len = kva->pkt_len;
>  		data_kva = kva->buf_addr + kva->data_off - kni->mbuf_va +
>  				kni->mbuf_kva;
> 
> @@ -338,20 +358,39 @@ kni_net_rx_lo_fifo_skb(struct kni_dev *kni)
>  		if (skb == NULL) {
>  			KNI_ERR("Out of mem, dropping pkts\n");
>  			kni->stats.rx_dropped++;
> +			continue;
>  		}
> -		else {
> -			/* Align IP on 16B boundary */
> -			skb_reserve(skb, 2);
> +
> +		/* Align IP on 16B boundary */
> +		skb_reserve(skb, 2);
> +
> +		if (kva->nb_segs == 0) {
The same commnets as above.

>  			memcpy(skb_put(skb, len), data_kva, len);
> -			skb->dev = dev;
> -			skb->ip_summed = CHECKSUM_UNNECESSARY;
> +		} else {
> +			int nb_segs;
> +			int kva_nb_segs = kva->nb_segs;
> 
> -			kni->stats.rx_bytes += len;
> -			kni->stats.rx_packets++;
> +			for (nb_segs = 0; nb_segs < kva_nb_segs; nb_segs++)
The same comments as above.
> {
> +				memcpy(skb_put(skb, kva->data_len),
> +					data_kva, kva->data_len);
> +
> +				if (!kva->next)
> +					break;
> 
> -			/* call tx interface */
> -			kni_net_tx(skb, dev);
> +				kva = kva->next - kni->mbuf_va + kni-
> >mbuf_kva;
> +				data_kva = kva->buf_addr + kva->data_off
> +					- kni->mbuf_va + kni->mbuf_kva;
> +			}
>  		}
> +
> +		skb->dev = dev;
> +		skb->ip_summed = CHECKSUM_UNNECESSARY;
> +
> +		kni->stats.rx_bytes += len;
> +		kni->stats.rx_packets++;
> +
> +		/* call tx interface */
> +		kni_net_tx(skb, dev);
>  	}
> 
>  	/* enqueue all the mbufs from rx_q into free_q */
> --
> 2.5.5