On 03/09/2016 11:59, sean.w...@mediatek.com wrote:
> From: Sean Wang <sean.w...@mediatek.com>
> 
> The patch adds support for aggregating more SKBs feed into NAPI in
> order to get more benefits from generic receive offload (GRO) by
> peeking at the RX ring status and moving more packets right before
> returning from NAPI RX polling handler if NAPI budgets are still
> available and some packets already present in hardware.
> 
> Signed-off-by: Sean Wang <sean.w...@mediatek.com>

this looks ok to me, gave it a quick try on my HW and it works well. i
am just not sure if this is something that is commonly done. someone
with more overview of how NAPI should be used might want to comment on this.

Tested-by: John Crispin <j...@phrozen.org>


> ---
>  drivers/net/ethernet/mediatek/mtk_eth_soc.c | 31 
> ++++++++++++++++-------------
>  1 file changed, 17 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mediatek/mtk_eth_soc.c 
> b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> index a1bdb53..66fd45a 100644
> --- a/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> +++ b/drivers/net/ethernet/mediatek/mtk_eth_soc.c
> @@ -893,14 +893,14 @@ release_desc:
>  
>               done++;
>       }
> -     /* make sure that all changes to the dma ring are flushed before
> -      * we continue
> -      */
> -     wmb();
> -     mtk_w32(eth, ring->calc_idx, MTK_PRX_CRX_IDX0);
>  
> -     if (done < budget)
> -             mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_STATUS);
> +     if (done) {
> +             /* make sure that all changes to the dma ring are flushed before
> +              * we continue
> +              */
> +             wmb();
> +             mtk_w32(eth, ring->calc_idx, MTK_PRX_CRX_IDX0);
> +     }
>  
>       return done;
>  }
> @@ -1020,10 +1020,13 @@ static int mtk_napi_rx(struct napi_struct *napi, int 
> budget)
>       struct mtk_eth *eth = container_of(napi, struct mtk_eth, rx_napi);
>       u32 status, mask;
>       int rx_done = 0;
> +     int remain_budget = budget;
>  
>       mtk_handle_status_irq(eth);
> +
> +poll_again:
>       mtk_w32(eth, MTK_RX_DONE_INT, MTK_PDMA_INT_STATUS);
> -     rx_done = mtk_poll_rx(napi, budget, eth);
> +     rx_done = mtk_poll_rx(napi, remain_budget, eth);
>  
>       if (unlikely(netif_msg_intr(eth))) {
>               status = mtk_r32(eth, MTK_PDMA_INT_STATUS);
> @@ -1032,18 +1035,18 @@ static int mtk_napi_rx(struct napi_struct *napi, int 
> budget)
>                        "done rx %d, intr 0x%08x/0x%x\n",
>                        rx_done, status, mask);
>       }
> -
> -     if (rx_done == budget)
> +     if (rx_done == remain_budget)
>               return budget;
>  
>       status = mtk_r32(eth, MTK_PDMA_INT_STATUS);
> -     if (status & MTK_RX_DONE_INT)
> -             return budget;
> -
> +     if (status & MTK_RX_DONE_INT) {
> +             remain_budget -= rx_done;
> +             goto poll_again;
> +     }
>       napi_complete(napi);
>       mtk_irq_enable(eth, MTK_PDMA_INT_MASK, MTK_RX_DONE_INT);
>  
> -     return rx_done;
> +     return rx_done + budget - remain_budget;
>  }
>  
>  static int mtk_tx_alloc(struct mtk_eth *eth)
> 

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