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Message-ID: <20200107135313.GA121856@apalos.home>
Date: Tue, 7 Jan 2020 15:53:13 +0200
From: Ilias Apalodimas <ilias.apalodimas@...aro.org>
To: Lorenzo Bianconi <lorenzo@...nel.org>
Cc: netdev@...r.kernel.org, brouer@...hat.com, davem@...emloft.net,
lorenzo.bianconi@...hat.com
Subject: Re: [RFC/RFT net-next] net: socionext: get rid of huge dma sync in
netsec_alloc_rx_data
Hi Lorenzo,
Although the box using thei NIC usually runs with coherent DMA, there's a
configuration that disables that. So having this is has some meaning.
Minor comments below.
On Sun, Jan 05, 2020 at 12:57:56PM +0100, Lorenzo Bianconi wrote:
> Socionext driver can run on dma coherent and non-coherent devices.
> Get rid of huge dma_sync_single_for_device in netsec_alloc_rx_data since
> now the driver can let page_pool API to managed needed DMA sync
>
> Signed-off-by: Lorenzo Bianconi <lorenzo@...nel.org>
> ---
> drivers/net/ethernet/socionext/netsec.c | 60 ++++++++++++++-----------
> 1 file changed, 33 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/net/ethernet/socionext/netsec.c b/drivers/net/ethernet/socionext/netsec.c
> index b5a9e947a4a8..7a2eb0e71d2a 100644
> --- a/drivers/net/ethernet/socionext/netsec.c
> +++ b/drivers/net/ethernet/socionext/netsec.c
> @@ -243,6 +243,7 @@
> NET_IP_ALIGN)
> #define NETSEC_RX_BUF_NON_DATA (NETSEC_RXBUF_HEADROOM + \
> SKB_DATA_ALIGN(sizeof(struct skb_shared_info)))
> +#define NETSEC_RX_BUF_SIZE (PAGE_SIZE - NETSEC_RX_BUF_NON_DATA)
>
> #define DESC_SZ sizeof(struct netsec_de)
>
> @@ -714,12 +715,11 @@ static void netsec_process_tx(struct netsec_priv *priv)
> }
>
> static void *netsec_alloc_rx_data(struct netsec_priv *priv,
> - dma_addr_t *dma_handle, u16 *desc_len)
i'd prefer having this function fill in the size, insetad of defining it every
time we refill the descriptors
You can keep the new define for PAGE_SIZE - NETSEC_RX_BUF_NON_DATA, it looks
cleaner
> + dma_addr_t *dma_handle)
>
> {
>
> struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];
> - enum dma_data_direction dma_dir;
> struct page *page;
>
> page = page_pool_dev_alloc_pages(dring->page_pool);
> @@ -734,10 +734,6 @@ static void *netsec_alloc_rx_data(struct netsec_priv *priv,
> /* Make sure the incoming payload fits in the page for XDP and non-XDP
> * cases and reserve enough space for headroom + skb_shared_info
> */
> - *desc_len = PAGE_SIZE - NETSEC_RX_BUF_NON_DATA;
> - dma_dir = page_pool_get_dma_dir(dring->page_pool);
> - dma_sync_single_for_device(priv->dev, *dma_handle, *desc_len, dma_dir);
> -
> return page_address(page);
> }
>
> @@ -883,6 +879,7 @@ static u32 netsec_xdp_xmit_back(struct netsec_priv *priv, struct xdp_buff *xdp)
> static u32 netsec_run_xdp(struct netsec_priv *priv, struct bpf_prog *prog,
> struct xdp_buff *xdp)
> {
> + struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];
> u32 ret = NETSEC_XDP_PASS;
> int err;
> u32 act;
> @@ -896,7 +893,10 @@ static u32 netsec_run_xdp(struct netsec_priv *priv, struct bpf_prog *prog,
> case XDP_TX:
> ret = netsec_xdp_xmit_back(priv, xdp);
> if (ret != NETSEC_XDP_TX)
> - xdp_return_buff(xdp);
> + __page_pool_put_page(dring->page_pool,
> + virt_to_head_page(xdp->data),
> + xdp->data_end - xdp->data_hard_start,
> + true);
> break;
> case XDP_REDIRECT:
> err = xdp_do_redirect(priv->ndev, xdp, prog);
> @@ -904,7 +904,10 @@ static u32 netsec_run_xdp(struct netsec_priv *priv, struct bpf_prog *prog,
> ret = NETSEC_XDP_REDIR;
> } else {
> ret = NETSEC_XDP_CONSUMED;
> - xdp_return_buff(xdp);
> + __page_pool_put_page(dring->page_pool,
> + virt_to_head_page(xdp->data),
> + xdp->data_end - xdp->data_hard_start,
> + true);
> }
> break;
> default:
> @@ -915,7 +918,10 @@ static u32 netsec_run_xdp(struct netsec_priv *priv, struct bpf_prog *prog,
> /* fall through -- handle aborts by dropping packet */
> case XDP_DROP:
> ret = NETSEC_XDP_CONSUMED;
> - xdp_return_buff(xdp);
> + __page_pool_put_page(dring->page_pool,
> + virt_to_head_page(xdp->data),
> + xdp->data_end - xdp->data_hard_start,
> + true);
> break;
> }
>
> @@ -944,10 +950,10 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
> struct netsec_desc *desc = &dring->desc[idx];
> struct page *page = virt_to_page(desc->addr);
> u32 xdp_result = XDP_PASS;
> - u16 pkt_len, desc_len;
> dma_addr_t dma_handle;
> struct xdp_buff xdp;
> void *buf_addr;
> + u16 pkt_len;
>
> if (de->attr & (1U << NETSEC_RX_PKT_OWN_FIELD)) {
> /* reading the register clears the irq */
> @@ -982,8 +988,7 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
> /* allocate a fresh buffer and map it to the hardware.
> * This will eventually replace the old buffer in the hardware
> */
> - buf_addr = netsec_alloc_rx_data(priv, &dma_handle, &desc_len);
> -
> + buf_addr = netsec_alloc_rx_data(priv, &dma_handle);
> if (unlikely(!buf_addr))
> break;
>
> @@ -1014,7 +1019,8 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
> * cache state. Since we paid the allocation cost if
> * building an skb fails try to put the page into cache
> */
> - page_pool_recycle_direct(dring->page_pool, page);
> + __page_pool_put_page(dring->page_pool, page,
> + desc->len, true);
> netif_err(priv, drv, priv->ndev,
> "rx failed to build skb\n");
> break;
> @@ -1037,7 +1043,7 @@ static int netsec_process_rx(struct netsec_priv *priv, int budget)
> }
>
> /* Update the descriptor with fresh buffers */
> - desc->len = desc_len;
> + desc->len = NETSEC_RX_BUF_SIZE;
Similar comment here, i'd prefer having a sinlge fucntion calculate the length.
> desc->dma_addr = dma_handle;
> desc->addr = buf_addr;
>
> @@ -1272,17 +1278,19 @@ static int netsec_setup_rx_dring(struct netsec_priv *priv)
> {
> struct netsec_desc_ring *dring = &priv->desc_ring[NETSEC_RING_RX];
> struct bpf_prog *xdp_prog = READ_ONCE(priv->xdp_prog);
> - struct page_pool_params pp_params = { 0 };
> + struct page_pool_params pp_params = {
> + .order = 0,
> + /* internal DMA mapping in page_pool */
> + .flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
> + .pool_size = DESC_NUM,
> + .nid = NUMA_NO_NODE,
> + .dev = priv->dev,
> + .dma_dir = xdp_prog ? DMA_BIDIRECTIONAL : DMA_FROM_DEVICE,
> + .offset = NETSEC_RXBUF_HEADROOM,
> + .max_len = NETSEC_RX_BUF_SIZE,
> + };
> int i, err;
>
> - pp_params.order = 0;
> - /* internal DMA mapping in page_pool */
> - pp_params.flags = PP_FLAG_DMA_MAP;
> - pp_params.pool_size = DESC_NUM;
> - pp_params.nid = NUMA_NO_NODE;
> - pp_params.dev = priv->dev;
> - pp_params.dma_dir = xdp_prog ? DMA_BIDIRECTIONAL : DMA_FROM_DEVICE;
> -
> dring->page_pool = page_pool_create(&pp_params);
> if (IS_ERR(dring->page_pool)) {
> err = PTR_ERR(dring->page_pool);
> @@ -1303,17 +1311,15 @@ static int netsec_setup_rx_dring(struct netsec_priv *priv)
> struct netsec_desc *desc = &dring->desc[i];
> dma_addr_t dma_handle;
> void *buf;
> - u16 len;
> -
> - buf = netsec_alloc_rx_data(priv, &dma_handle, &len);
>
> + buf = netsec_alloc_rx_data(priv, &dma_handle);
> if (!buf) {
> err = -ENOMEM;
> goto err_out;
> }
> + desc->len = NETSEC_RX_BUF_SIZE;
> desc->dma_addr = dma_handle;
> desc->addr = buf;
> - desc->len = len;
> }
>
> netsec_rx_fill(priv, 0, DESC_NUM);
> --
> 2.21.1
>
Other than that this looks good, re-send it as a non RFC patch and i can test it
Thanks!
/Ilias
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