From d27de0ef5ef995df2cc5f5c006c0efcf0a62b6af Mon Sep 17 00:00:00 2001 From: Sieng Piaw Liew Date: Wed, 6 Jan 2021 22:42:07 +0800 Subject: [PATCH 6/7] bcm63xx_enet: convert to build_skb We can increase the efficiency of rx path by using buffers to receive packets then build SKBs around them just before passing into the network stack. In contrast, preallocating SKBs too early reduces CPU cache efficiency. Check if we're in NAPI context when refilling RX. Normally we're almost always running in NAPI context. Dispatch to napi_alloc_frag directly instead of relying on netdev_alloc_frag which does the same but with the overhead of local_bh_disable/enable. Tested on BCM6328 320 MHz and iperf3 -M 512 to measure packet/sec performance. Included netif_receive_skb_list and NET_IP_ALIGN optimizations. Before: [ ID] Interval Transfer Bandwidth Retr [ 4] 0.00-10.00 sec 49.9 MBytes 41.9 Mbits/sec 197 sender [ 4] 0.00-10.00 sec 49.3 MBytes 41.3 Mbits/sec receiver After: [ ID] Interval Transfer Bandwidth Retr [ 4] 0.00-30.00 sec 171 MBytes 47.8 Mbits/sec 272 sender [ 4] 0.00-30.00 sec 170 MBytes 47.6 Mbits/sec receiver Signed-off-by: Sieng Piaw Liew Acked-by: Florian Fainelli Signed-off-by: Jakub Kicinski --- drivers/net/ethernet/broadcom/bcm63xx_enet.c | 111 ++++++++++--------- drivers/net/ethernet/broadcom/bcm63xx_enet.h | 14 ++- 2 files changed, 71 insertions(+), 54 deletions(-) --- a/drivers/net/ethernet/broadcom/bcm63xx_enet.c +++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.c @@ -220,7 +220,7 @@ static void bcm_enet_mdio_write_mii(stru /* * refill rx queue */ -static int bcm_enet_refill_rx(struct net_device *dev) +static int bcm_enet_refill_rx(struct net_device *dev, bool napi_mode) { struct bcm_enet_priv *priv; @@ -228,29 +228,29 @@ static int bcm_enet_refill_rx(struct net while (priv->rx_desc_count < priv->rx_ring_size) { struct bcm_enet_desc *desc; - struct sk_buff *skb; - dma_addr_t p; int desc_idx; u32 len_stat; desc_idx = priv->rx_dirty_desc; desc = &priv->rx_desc_cpu[desc_idx]; - if (!priv->rx_skb[desc_idx]) { - if (priv->enet_is_sw) - skb = netdev_alloc_skb_ip_align(dev, priv->rx_skb_size); + if (!priv->rx_buf[desc_idx]) { + void *buf; + + if (likely(napi_mode)) + buf = napi_alloc_frag(priv->rx_frag_size); else - skb = netdev_alloc_skb(dev, priv->rx_skb_size); - if (!skb) + buf = netdev_alloc_frag(priv->rx_frag_size); + if (unlikely(!buf)) break; - priv->rx_skb[desc_idx] = skb; - p = dma_map_single(&priv->pdev->dev, skb->data, - priv->rx_skb_size, - DMA_FROM_DEVICE); - desc->address = p; + priv->rx_buf[desc_idx] = buf; + desc->address = dma_map_single(&priv->pdev->dev, + buf + priv->rx_buf_offset, + priv->rx_buf_size, + DMA_FROM_DEVICE); } - len_stat = priv->rx_skb_size << DMADESC_LENGTH_SHIFT; + len_stat = priv->rx_buf_size << DMADESC_LENGTH_SHIFT; len_stat |= DMADESC_OWNER_MASK; if (priv->rx_dirty_desc == priv->rx_ring_size - 1) { len_stat |= (DMADESC_WRAP_MASK >> priv->dma_desc_shift); @@ -290,7 +290,7 @@ static void bcm_enet_refill_rx_timer(str struct net_device *dev = priv->net_dev; spin_lock(&priv->rx_lock); - bcm_enet_refill_rx(dev); + bcm_enet_refill_rx(dev, false); spin_unlock(&priv->rx_lock); } @@ -320,6 +320,7 @@ static int bcm_enet_receive_queue(struct int desc_idx; u32 len_stat; unsigned int len; + void *buf; desc_idx = priv->rx_curr_desc; desc = &priv->rx_desc_cpu[desc_idx]; @@ -365,16 +366,14 @@ static int bcm_enet_receive_queue(struct } /* valid packet */ - skb = priv->rx_skb[desc_idx]; + buf = priv->rx_buf[desc_idx]; len = (len_stat & DMADESC_LENGTH_MASK) >> DMADESC_LENGTH_SHIFT; /* don't include FCS */ len -= 4; if (len < copybreak) { - struct sk_buff *nskb; - - nskb = napi_alloc_skb(&priv->napi, len); - if (!nskb) { + skb = napi_alloc_skb(&priv->napi, len); + if (unlikely(!skb)) { /* forget packet, just rearm desc */ dev->stats.rx_dropped++; continue; @@ -382,14 +381,21 @@ static int bcm_enet_receive_queue(struct dma_sync_single_for_cpu(kdev, desc->address, len, DMA_FROM_DEVICE); - memcpy(nskb->data, skb->data, len); + memcpy(skb->data, buf + priv->rx_buf_offset, len); dma_sync_single_for_device(kdev, desc->address, len, DMA_FROM_DEVICE); - skb = nskb; } else { - dma_unmap_single(&priv->pdev->dev, desc->address, - priv->rx_skb_size, DMA_FROM_DEVICE); - priv->rx_skb[desc_idx] = NULL; + dma_unmap_single(kdev, desc->address, + priv->rx_buf_size, DMA_FROM_DEVICE); + priv->rx_buf[desc_idx] = NULL; + + skb = build_skb(buf, priv->rx_frag_size); + if (unlikely(!skb)) { + skb_free_frag(buf); + dev->stats.rx_dropped++; + continue; + } + skb_reserve(skb, priv->rx_buf_offset); } skb_put(skb, len); @@ -403,7 +409,7 @@ static int bcm_enet_receive_queue(struct netif_receive_skb_list(&rx_list); if (processed || !priv->rx_desc_count) { - bcm_enet_refill_rx(dev); + bcm_enet_refill_rx(dev, true); /* kick rx dma */ enet_dmac_writel(priv, priv->dma_chan_en_mask, @@ -860,22 +866,22 @@ static void bcm_enet_adjust_link(struct priv->pause_tx ? "tx" : "off"); } -static void bcm_enet_free_rx_skb_ring(struct device *kdev, struct bcm_enet_priv *priv) +static void bcm_enet_free_rx_buf_ring(struct device *kdev, struct bcm_enet_priv *priv) { int i; for (i = 0; i < priv->rx_ring_size; i++) { struct bcm_enet_desc *desc; - if (!priv->rx_skb[i]) + if (!priv->rx_buf[i]) continue; desc = &priv->rx_desc_cpu[i]; - dma_unmap_single(kdev, desc->address, priv->rx_skb_size, + dma_unmap_single(kdev, desc->address, priv->rx_buf_size, DMA_FROM_DEVICE); - kfree_skb(priv->rx_skb[i]); + skb_free_frag(priv->rx_buf[i]); } - kfree(priv->rx_skb); + kfree(priv->rx_buf); } /* @@ -987,10 +993,10 @@ static int bcm_enet_open(struct net_devi priv->tx_curr_desc = 0; spin_lock_init(&priv->tx_lock); - /* init & fill rx ring with skbs */ - priv->rx_skb = kcalloc(priv->rx_ring_size, sizeof(struct sk_buff *), + /* init & fill rx ring with buffers */ + priv->rx_buf = kcalloc(priv->rx_ring_size, sizeof(void *), GFP_KERNEL); - if (!priv->rx_skb) { + if (!priv->rx_buf) { ret = -ENOMEM; goto out_free_tx_skb; } @@ -1007,8 +1013,8 @@ static int bcm_enet_open(struct net_devi enet_dmac_writel(priv, ENETDMA_BUFALLOC_FORCE_MASK | 0, ENETDMAC_BUFALLOC, priv->rx_chan); - if (bcm_enet_refill_rx(dev)) { - dev_err(kdev, "cannot allocate rx skb queue\n"); + if (bcm_enet_refill_rx(dev, false)) { + dev_err(kdev, "cannot allocate rx buffer queue\n"); ret = -ENOMEM; goto out; } @@ -1102,7 +1108,7 @@ static int bcm_enet_open(struct net_devi return 0; out: - bcm_enet_free_rx_skb_ring(kdev, priv); + bcm_enet_free_rx_buf_ring(kdev, priv); out_free_tx_skb: kfree(priv->tx_skb); @@ -1208,8 +1214,8 @@ static int bcm_enet_stop(struct net_devi /* force reclaim of all tx buffers */ bcm_enet_tx_reclaim(dev, 1); - /* free the rx skb ring */ - bcm_enet_free_rx_skb_ring(kdev, priv); + /* free the rx buffer ring */ + bcm_enet_free_rx_buf_ring(kdev, priv); /* free remaining allocated memory */ kfree(priv->tx_skb); @@ -1633,9 +1639,12 @@ static int bcm_enet_change_mtu(struct ne * align rx buffer size to dma burst len, account FCS since * it's appended */ - priv->rx_skb_size = ALIGN(actual_mtu + ETH_FCS_LEN, + priv->rx_buf_size = ALIGN(actual_mtu + ETH_FCS_LEN, priv->dma_maxburst * 4); + priv->rx_frag_size = SKB_DATA_ALIGN(priv->rx_buf_offset + priv->rx_buf_size) + + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); + dev->mtu = new_mtu; return 0; } @@ -1720,6 +1729,7 @@ static int bcm_enet_probe(struct platfor priv->enet_is_sw = false; priv->dma_maxburst = BCMENET_DMA_MAXBURST; + priv->rx_buf_offset = NET_SKB_PAD; ret = bcm_enet_change_mtu(dev, dev->mtu); if (ret) @@ -2137,7 +2147,7 @@ static int bcm_enetsw_open(struct net_de priv->tx_skb = kcalloc(priv->tx_ring_size, sizeof(struct sk_buff *), GFP_KERNEL); if (!priv->tx_skb) { - dev_err(kdev, "cannot allocate rx skb queue\n"); + dev_err(kdev, "cannot allocate tx skb queue\n"); ret = -ENOMEM; goto out_free_tx_ring; } @@ -2147,11 +2157,11 @@ static int bcm_enetsw_open(struct net_de priv->tx_curr_desc = 0; spin_lock_init(&priv->tx_lock); - /* init & fill rx ring with skbs */ - priv->rx_skb = kcalloc(priv->rx_ring_size, sizeof(struct sk_buff *), + /* init & fill rx ring with buffers */ + priv->rx_buf = kcalloc(priv->rx_ring_size, sizeof(void *), GFP_KERNEL); - if (!priv->rx_skb) { - dev_err(kdev, "cannot allocate rx skb queue\n"); + if (!priv->rx_buf) { + dev_err(kdev, "cannot allocate rx buffer queue\n"); ret = -ENOMEM; goto out_free_tx_skb; } @@ -2198,8 +2208,8 @@ static int bcm_enetsw_open(struct net_de enet_dma_writel(priv, ENETDMA_BUFALLOC_FORCE_MASK | 0, ENETDMA_BUFALLOC_REG(priv->rx_chan)); - if (bcm_enet_refill_rx(dev)) { - dev_err(kdev, "cannot allocate rx skb queue\n"); + if (bcm_enet_refill_rx(dev, false)) { + dev_err(kdev, "cannot allocate rx buffer queue\n"); ret = -ENOMEM; goto out; } @@ -2298,7 +2308,7 @@ static int bcm_enetsw_open(struct net_de return 0; out: - bcm_enet_free_rx_skb_ring(kdev, priv); + bcm_enet_free_rx_buf_ring(kdev, priv); out_free_tx_skb: kfree(priv->tx_skb); @@ -2348,8 +2358,8 @@ static int bcm_enetsw_stop(struct net_de /* force reclaim of all tx buffers */ bcm_enet_tx_reclaim(dev, 1); - /* free the rx skb ring */ - bcm_enet_free_rx_skb_ring(kdev, priv); + /* free the rx buffer ring */ + bcm_enet_free_rx_buf_ring(kdev, priv); /* free remaining allocated memory */ kfree(priv->tx_skb); @@ -2648,6 +2658,7 @@ static int bcm_enetsw_probe(struct platf priv->rx_ring_size = BCMENET_DEF_RX_DESC; priv->tx_ring_size = BCMENET_DEF_TX_DESC; priv->dma_maxburst = BCMENETSW_DMA_MAXBURST; + priv->rx_buf_offset = NET_SKB_PAD + NET_IP_ALIGN; pd = dev_get_platdata(&pdev->dev); if (pd) { --- a/drivers/net/ethernet/broadcom/bcm63xx_enet.h +++ b/drivers/net/ethernet/broadcom/bcm63xx_enet.h @@ -230,11 +230,17 @@ struct bcm_enet_priv { /* next dirty rx descriptor to refill */ int rx_dirty_desc; - /* size of allocated rx skbs */ - unsigned int rx_skb_size; + /* size of allocated rx buffers */ + unsigned int rx_buf_size; - /* list of skb given to hw for rx */ - struct sk_buff **rx_skb; + /* allocated rx buffer offset */ + unsigned int rx_buf_offset; + + /* size of allocated rx frag */ + unsigned int rx_frag_size; + + /* list of buffer given to hw for rx */ + void **rx_buf; /* used when rx skb allocation failed, so we defer rx queue * refill */