Subject: Re: [PATCH net-next v3] octeontx2-pf: Add support for page pool

From: Simon Horman <[email-masked]>
Date: Fri, 19 May 2023 12:02:44 +0200

On Fri, May 19, 2023 at 12:43:52PM +0530, Ratheesh Kannoth wrote:
> Page pool for each rx queue enhance rx side performance
> by reclaiming buffers back to each queue specific pool. DMA
> mapping is done only for first allocation of buffers.
> As subsequent buffers allocation avoid DMA mapping,
> it results in performance improvement.
> 
> Image        |  Performance
> ------------ | ------------
> Vannila      |   3Mpps
>              |
> with this    |   42Mpps
> change	     |
> ---------------------------
> 
> Signed-off-by: Ratheesh Kannoth <[email-masked]>

...

> @@ -1205,10 +1226,28 @@ void otx2_sq_free_sqbs(struct otx2_nic *pfvf)
>  	}
>  }
>  
> +void otx2_free_bufs(struct otx2_nic *pfvf, struct otx2_pool *pool,
> +		    u64 iova, int size)
> +{
> +	u64 pa = otx2_iova_to_phys(pfvf->iommu_domain, iova);
> +	struct page *page = virt_to_head_page(phys_to_virt(pa));

nit: please arrange local variables in networking code in reverse xmas tree
     order - longest line to shortest.

	u64 pa = otx2_iova_to_phys(pfvf->iommu_domain, iova);
	struct page *page;

	page = virt_to_head_page(phys_to_virt(pa));

     The following tool can check this:

        https://github.com/ecree-solarflare/xmastree

...

> @@ -1186,11 +1185,13 @@ bool otx2_sq_append_skb(struct net_device *netdev, struct otx2_snd_queue *sq,
>  }
>  EXPORT_SYMBOL(otx2_sq_append_skb);
>  
> -void otx2_cleanup_rx_cqes(struct otx2_nic *pfvf, struct otx2_cq_queue *cq)
> +void otx2_cleanup_rx_cqes(struct otx2_nic *pfvf, struct otx2_cq_queue *cq, int qidx)
>  {
>  	struct nix_cqe_rx_s *cqe;
>  	int processed_cqe = 0;
> -	u64 iova, pa;
> +	struct otx2_pool *pool;
> +	u16 pool_id;
> +	u64 iova;

Likewise here.

>  
>  	if (pfvf->xdp_prog)
>  		xdp_rxq_info_unreg(&cq->xdp_rxq);

...