Re: [PATCH net-next1/2] net: core: use listified Rx for GRO_NORMAL in napi_gro_receive()

[Edward Cree]

On 10/10/2019 15:42, Alexander Lobakin wrote:
> Commit 323ebb61e32b4 ("net: use listified RX for handling GRO_NORMAL
> skbs") made use of listified skb processing for the users of
> napi_gro_frags().
> The same technique can be used in a way more common napi_gro_receive()
> to speed up non-merged (GRO_NORMAL) skbs for a wide range of drivers,
> including gro_cells and mac80211 users.
>
> Signed-off-by: Alexander Lobakin <alobakin@xxxxxxxx>
> ---
>  net/core/dev.c | 49 +++++++++++++++++++++++++------------------------
>  1 file changed, 25 insertions(+), 24 deletions(-)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 8bc3dce71fc0..a33f56b439ce 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -5884,6 +5884,26 @@ struct packet_offload *gro_find_complete_by_type(__be16 type)
>  }
>  EXPORT_SYMBOL(gro_find_complete_by_type);
>  
> +/* Pass the currently batched GRO_NORMAL SKBs up to the stack. */
> +static void gro_normal_list(struct napi_struct *napi)
> +{
> +	if (!napi->rx_count)
> +		return;
> +	netif_receive_skb_list_internal(&napi->rx_list);
> +	INIT_LIST_HEAD(&napi->rx_list);
> +	napi->rx_count = 0;
> +}
> +
> +/* Queue one GRO_NORMAL SKB up for list processing.  If batch size exceeded,
> + * pass the whole batch up to the stack.
> + */
> +static void gro_normal_one(struct napi_struct *napi, struct sk_buff *skb)
> +{
> +	list_add_tail(&skb->list, &napi->rx_list);
> +	if (++napi->rx_count >= gro_normal_batch)
> +		gro_normal_list(napi);
> +}
> +
>  static void napi_skb_free_stolen_head(struct sk_buff *skb)
>  {
>  	skb_dst_drop(skb);
> @@ -5891,12 +5911,13 @@ static void napi_skb_free_stolen_head(struct sk_buff *skb)
>  	kmem_cache_free(skbuff_head_cache, skb);
>  }
>  
> -static gro_result_t napi_skb_finish(gro_result_t ret, struct sk_buff *skb)
> +static gro_result_t napi_skb_finish(struct napi_struct *napi,
> +				    struct sk_buff *skb,
> +				    gro_result_t ret)
Any reason why the argument order here is changed around?

-Ed
>  {
>  	switch (ret) {
>  	case GRO_NORMAL:
> -		if (netif_receive_skb_internal(skb))
> -			ret = GRO_DROP;
> +		gro_normal_one(napi, skb);
>  		break;
>  
>  	case GRO_DROP:
> @@ -5928,7 +5949,7 @@ gro_result_t napi_gro_receive(struct napi_struct *napi, struct sk_buff *skb)
>  
>  	skb_gro_reset_offset(skb);
>  
> -	ret = napi_skb_finish(dev_gro_receive(napi, skb), skb);
> +	ret = napi_skb_finish(napi, skb, dev_gro_receive(napi, skb));
>  	trace_napi_gro_receive_exit(ret);
>  
>  	return ret;
> @@ -5974,26 +5995,6 @@ struct sk_buff *napi_get_frags(struct napi_struct *napi)
>  }
>  EXPORT_SYMBOL(napi_get_frags);
>  
> -/* Pass the currently batched GRO_NORMAL SKBs up to the stack. */
> -static void gro_normal_list(struct napi_struct *napi)
> -{
> -	if (!napi->rx_count)
> -		return;
> -	netif_receive_skb_list_internal(&napi->rx_list);
> -	INIT_LIST_HEAD(&napi->rx_list);
> -	napi->rx_count = 0;
> -}
> -
> -/* Queue one GRO_NORMAL SKB up for list processing.  If batch size exceeded,
> - * pass the whole batch up to the stack.
> - */
> -static void gro_normal_one(struct napi_struct *napi, struct sk_buff *skb)
> -{
> -	list_add_tail(&skb->list, &napi->rx_list);
> -	if (++napi->rx_count >= gro_normal_batch)
> -		gro_normal_list(napi);
> -}
> -
>  static gro_result_t napi_frags_finish(struct napi_struct *napi,
>  				      struct sk_buff *skb,
>  				      gro_result_t ret)