+++ /dev/null
-From e015593573b3e3f74bd8a63c05fa92902194a354 Mon Sep 17 00:00:00 2001
-From: Aleksander Jan Bajkowski <olek2@wp.pl>
-Date: Tue, 4 Jan 2022 16:11:44 +0100
-Subject: [PATCH 715/715] net: lantiq_xrx200: 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.
-
-NAT Performance results on BT Home Hub 5A (kernel 5.10.89, mtu 1500):
-
- Down Up
-Before 577 Mbps 648 Mbps
-After 624 Mbps 695 Mbps
-
-Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
-Signed-off-by: Jakub Kicinski <kuba@kernel.org>
----
- drivers/net/ethernet/lantiq_xrx200.c | 56 ++++++++++++++++++----------
- 1 file changed, 36 insertions(+), 20 deletions(-)
-
---- a/drivers/net/ethernet/lantiq_xrx200.c
-+++ b/drivers/net/ethernet/lantiq_xrx200.c
-@@ -63,7 +63,11 @@ struct xrx200_chan {
-
- struct napi_struct napi;
- struct ltq_dma_channel dma;
-- struct sk_buff *skb[LTQ_DESC_NUM];
-+
-+ union {
-+ struct sk_buff *skb[LTQ_DESC_NUM];
-+ void *rx_buff[LTQ_DESC_NUM];
-+ };
-
- struct sk_buff *skb_head;
- struct sk_buff *skb_tail;
-@@ -78,6 +82,7 @@ struct xrx200_priv {
- struct xrx200_chan chan_rx;
-
- u16 rx_buf_size;
-+ u16 rx_skb_size;
-
- struct net_device *net_dev;
- struct device *dev;
-@@ -115,6 +120,12 @@ static int xrx200_buffer_size(int mtu)
- return round_up(xrx200_max_frame_len(mtu), 4 * XRX200_DMA_BURST_LEN);
- }
-
-+static int xrx200_skb_size(u16 buf_size)
-+{
-+ return SKB_DATA_ALIGN(buf_size + NET_SKB_PAD + NET_IP_ALIGN) +
-+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
-+}
-+
- /* drop all the packets from the DMA ring */
- static void xrx200_flush_dma(struct xrx200_chan *ch)
- {
-@@ -173,30 +184,29 @@ static int xrx200_close(struct net_devic
- return 0;
- }
-
--static int xrx200_alloc_skb(struct xrx200_chan *ch)
-+static int xrx200_alloc_buf(struct xrx200_chan *ch, void *(*alloc)(unsigned int size))
- {
-- struct sk_buff *skb = ch->skb[ch->dma.desc];
-+ void *buf = ch->rx_buff[ch->dma.desc];
- struct xrx200_priv *priv = ch->priv;
- dma_addr_t mapping;
- int ret = 0;
-
-- ch->skb[ch->dma.desc] = netdev_alloc_skb_ip_align(priv->net_dev,
-- priv->rx_buf_size);
-- if (!ch->skb[ch->dma.desc]) {
-+ ch->rx_buff[ch->dma.desc] = alloc(priv->rx_skb_size);
-+ if (!ch->rx_buff[ch->dma.desc]) {
- ret = -ENOMEM;
- goto skip;
- }
-
-- mapping = dma_map_single(priv->dev, ch->skb[ch->dma.desc]->data,
-+ mapping = dma_map_single(priv->dev, ch->rx_buff[ch->dma.desc],
- priv->rx_buf_size, DMA_FROM_DEVICE);
- if (unlikely(dma_mapping_error(priv->dev, mapping))) {
-- dev_kfree_skb_any(ch->skb[ch->dma.desc]);
-- ch->skb[ch->dma.desc] = skb;
-+ skb_free_frag(ch->rx_buff[ch->dma.desc]);
-+ ch->rx_buff[ch->dma.desc] = buf;
- ret = -ENOMEM;
- goto skip;
- }
-
-- ch->dma.desc_base[ch->dma.desc].addr = mapping;
-+ ch->dma.desc_base[ch->dma.desc].addr = mapping + NET_SKB_PAD + NET_IP_ALIGN;
- /* Make sure the address is written before we give it to HW */
- wmb();
- skip:
-@@ -210,13 +220,14 @@ static int xrx200_hw_receive(struct xrx2
- {
- struct xrx200_priv *priv = ch->priv;
- struct ltq_dma_desc *desc = &ch->dma.desc_base[ch->dma.desc];
-- struct sk_buff *skb = ch->skb[ch->dma.desc];
-+ void *buf = ch->rx_buff[ch->dma.desc];
- u32 ctl = desc->ctl;
- int len = (ctl & LTQ_DMA_SIZE_MASK);
- struct net_device *net_dev = priv->net_dev;
-+ struct sk_buff *skb;
- int ret;
-
-- ret = xrx200_alloc_skb(ch);
-+ ret = xrx200_alloc_buf(ch, napi_alloc_frag);
-
- ch->dma.desc++;
- ch->dma.desc %= LTQ_DESC_NUM;
-@@ -227,19 +238,21 @@ static int xrx200_hw_receive(struct xrx2
- return ret;
- }
-
-+ skb = build_skb(buf, priv->rx_skb_size);
-+ skb_reserve(skb, NET_SKB_PAD);
- skb_put(skb, len);
-
- /* add buffers to skb via skb->frag_list */
- if (ctl & LTQ_DMA_SOP) {
- ch->skb_head = skb;
- ch->skb_tail = skb;
-+ skb_reserve(skb, NET_IP_ALIGN);
- } else if (ch->skb_head) {
- if (ch->skb_head == ch->skb_tail)
- skb_shinfo(ch->skb_tail)->frag_list = skb;
- else
- ch->skb_tail->next = skb;
- ch->skb_tail = skb;
-- skb_reserve(ch->skb_tail, -NET_IP_ALIGN);
- ch->skb_head->len += skb->len;
- ch->skb_head->data_len += skb->len;
- ch->skb_head->truesize += skb->truesize;
-@@ -395,12 +408,13 @@ xrx200_change_mtu(struct net_device *net
- struct xrx200_chan *ch_rx = &priv->chan_rx;
- int old_mtu = net_dev->mtu;
- bool running = false;
-- struct sk_buff *skb;
-+ void *buff;
- int curr_desc;
- int ret = 0;
-
- net_dev->mtu = new_mtu;
- priv->rx_buf_size = xrx200_buffer_size(new_mtu);
-+ priv->rx_skb_size = xrx200_skb_size(priv->rx_buf_size);
-
- if (new_mtu <= old_mtu)
- return ret;
-@@ -416,14 +430,15 @@ xrx200_change_mtu(struct net_device *net
-
- for (ch_rx->dma.desc = 0; ch_rx->dma.desc < LTQ_DESC_NUM;
- ch_rx->dma.desc++) {
-- skb = ch_rx->skb[ch_rx->dma.desc];
-- ret = xrx200_alloc_skb(ch_rx);
-+ buff = ch_rx->rx_buff[ch_rx->dma.desc];
-+ ret = xrx200_alloc_buf(ch_rx, netdev_alloc_frag);
- if (ret) {
- net_dev->mtu = old_mtu;
- priv->rx_buf_size = xrx200_buffer_size(old_mtu);
-+ priv->rx_skb_size = xrx200_skb_size(priv->rx_buf_size);
- break;
- }
-- dev_kfree_skb_any(skb);
-+ skb_free_frag(buff);
- }
-
- ch_rx->dma.desc = curr_desc;
-@@ -476,7 +491,7 @@ static int xrx200_dma_init(struct xrx200
- ltq_dma_alloc_rx(&ch_rx->dma);
- for (ch_rx->dma.desc = 0; ch_rx->dma.desc < LTQ_DESC_NUM;
- ch_rx->dma.desc++) {
-- ret = xrx200_alloc_skb(ch_rx);
-+ ret = xrx200_alloc_buf(ch_rx, netdev_alloc_frag);
- if (ret)
- goto rx_free;
- }
-@@ -511,7 +526,7 @@ rx_ring_free:
- /* free the allocated RX ring */
- for (i = 0; i < LTQ_DESC_NUM; i++) {
- if (priv->chan_rx.skb[i])
-- dev_kfree_skb_any(priv->chan_rx.skb[i]);
-+ skb_free_frag(priv->chan_rx.rx_buff[i]);
- }
-
- rx_free:
-@@ -528,7 +543,7 @@ static void xrx200_hw_cleanup(struct xrx
-
- /* free the allocated RX ring */
- for (i = 0; i < LTQ_DESC_NUM; i++)
-- dev_kfree_skb_any(priv->chan_rx.skb[i]);
-+ skb_free_frag(priv->chan_rx.rx_buff[i]);
- }
-
- static int xrx200_probe(struct platform_device *pdev)
-@@ -553,6 +568,7 @@ static int xrx200_probe(struct platform_
- net_dev->min_mtu = ETH_ZLEN;
- net_dev->max_mtu = XRX200_DMA_DATA_LEN - xrx200_max_frame_len(0);
- priv->rx_buf_size = xrx200_buffer_size(ETH_DATA_LEN);
-+ priv->rx_skb_size = xrx200_skb_size(priv->rx_buf_size);
-
- /* load the memory ranges */
- priv->pmac_reg = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
projects / openwrt / openwrt.git / blobdiff