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authorFelix Fietkau <nbd@openwrt.org>2012-05-28 02:55:59 +0000
committerFelix Fietkau <nbd@openwrt.org>2012-05-28 02:55:59 +0000
commit367e4b3994543e40437e4e73305af197c21c1055 (patch)
treea300a3143325d80331a823eb140a2bd3887d686c
parentb03dd7a531496e0d5c4a72afe3f4ee26799e3144 (diff)
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ar71xx: improve rx performance of the ethernet driver by using build_skb to deliver a cache-hot skb to the network stack
SVN-Revision: 31934
-rw-r--r--target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h6
-rw-r--r--target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c84
2 files changed, 49 insertions, 41 deletions
diff --git a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
index 8817416..b9d95ad 100644
--- a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
+++ b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx.h
@@ -53,6 +53,7 @@
#define AG71XX_TX_MTU_LEN 1540
#define AG71XX_RX_PKT_SIZE \
(ETH_FRAME_LEN + ETH_FCS_LEN + VLAN_HLEN)
+#define AG71XX_RX_BUF_SIZE (AG71XX_RX_PKT_SIZE + NET_SKB_PAD + NET_IP_ALIGN)
#define AG71XX_TX_RING_SIZE_DEFAULT 64
#define AG71XX_RX_RING_SIZE_DEFAULT 128
@@ -85,7 +86,10 @@ struct ag71xx_desc {
} __attribute__((aligned(4)));
struct ag71xx_buf {
- struct sk_buff *skb;
+ union {
+ struct sk_buff *skb;
+ void *rx_buf;
+ };
struct ag71xx_desc *desc;
dma_addr_t dma_addr;
unsigned long timestamp;
diff --git a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
index 6d1aff7..fb99d27 100644
--- a/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
+++ b/target/linux/ar71xx/files/drivers/net/ethernet/atheros/ag71xx/ag71xx_main.c
@@ -189,15 +189,17 @@ static void ag71xx_ring_rx_clean(struct ag71xx *ag)
return;
for (i = 0; i < ring->size; i++)
- if (ring->buf[i].skb) {
+ if (ring->buf[i].rx_buf) {
dma_unmap_single(&ag->dev->dev, ring->buf[i].dma_addr,
- AG71XX_RX_PKT_SIZE, DMA_FROM_DEVICE);
- kfree_skb(ring->buf[i].skb);
+ AG71XX_RX_BUF_SIZE, DMA_FROM_DEVICE);
+ kfree(ring->buf[i].rx_buf);
}
}
-struct sk_buff *ag71xx_rx_alloc(struct ag71xx *ag)
+static int ag71xx_buffer_offset(struct ag71xx *ag)
{
+ int offset = NET_SKB_PAD;
+
/*
* On AR71xx/AR91xx packets must be 4-byte aligned.
*
@@ -205,17 +207,35 @@ struct sk_buff *ag71xx_rx_alloc(struct ag71xx *ag)
* so we don't need any extra alignment in that case.
*/
if (!ag71xx_get_pdata(ag)->is_ar724x || ag71xx_has_ar8216(ag))
- return netdev_alloc_skb(ag->dev, AG71XX_RX_PKT_SIZE);
+ return offset;
- return netdev_alloc_skb_ip_align(ag->dev, AG71XX_RX_PKT_SIZE);
+ return offset + NET_IP_ALIGN;
}
+static bool ag71xx_fill_rx_buf(struct ag71xx *ag, struct ag71xx_buf *buf,
+ int offset)
+{
+ void *data;
+
+ data = kmalloc(AG71XX_RX_BUF_SIZE +
+ SKB_DATA_ALIGN(sizeof(struct skb_shared_info)),
+ GFP_ATOMIC);
+ if (!data)
+ return false;
+
+ buf->rx_buf = data;
+ buf->dma_addr = dma_map_single(&ag->dev->dev, data,
+ AG71XX_RX_BUF_SIZE, DMA_FROM_DEVICE);
+ buf->desc->data = (u32) buf->dma_addr + offset;
+ return true;
+}
static int ag71xx_ring_rx_init(struct ag71xx *ag)
{
struct ag71xx_ring *ring = &ag->rx_ring;
unsigned int i;
int ret;
+ int offset = ag71xx_buffer_offset(ag);
ret = 0;
for (i = 0; i < ring->size; i++) {
@@ -228,22 +248,11 @@ static int ag71xx_ring_rx_init(struct ag71xx *ag)
}
for (i = 0; i < ring->size; i++) {
- struct sk_buff *skb;
- dma_addr_t dma_addr;
-
- skb = ag71xx_rx_alloc(ag);
- if (!skb) {
+ if (!ag71xx_fill_rx_buf(ag, &ring->buf[i], offset)) {
ret = -ENOMEM;
break;
}
- skb->dev = ag->dev;
- dma_addr = dma_map_single(&ag->dev->dev, skb->data,
- AG71XX_RX_PKT_SIZE,
- DMA_FROM_DEVICE);
- ring->buf[i].skb = skb;
- ring->buf[i].dma_addr = dma_addr;
- ring->buf[i].desc->data = (u32) dma_addr;
ring->buf[i].desc->ctrl = DESC_EMPTY;
}
@@ -260,6 +269,7 @@ static int ag71xx_ring_rx_refill(struct ag71xx *ag)
{
struct ag71xx_ring *ring = &ag->rx_ring;
unsigned int count;
+ int offset = ag71xx_buffer_offset(ag);
count = 0;
for (; ring->curr - ring->dirty > 0; ring->dirty++) {
@@ -267,24 +277,9 @@ static int ag71xx_ring_rx_refill(struct ag71xx *ag)
i = ring->dirty % ring->size;
- if (ring->buf[i].skb == NULL) {
- dma_addr_t dma_addr;
- struct sk_buff *skb;
-
- skb = ag71xx_rx_alloc(ag);
- if (skb == NULL)
- break;
-
- skb->dev = ag->dev;
-
- dma_addr = dma_map_single(&ag->dev->dev, skb->data,
- AG71XX_RX_PKT_SIZE,
- DMA_FROM_DEVICE);
-
- ring->buf[i].skb = skb;
- ring->buf[i].dma_addr = dma_addr;
- ring->buf[i].desc->data = (u32) dma_addr;
- }
+ if (!ring->buf[i].rx_buf &&
+ !ag71xx_fill_rx_buf(ag, &ring->buf[i], offset))
+ break;
ring->buf[i].desc->ctrl = DESC_EMPTY;
count++;
@@ -863,6 +858,7 @@ static int ag71xx_rx_packets(struct ag71xx *ag, int limit)
{
struct net_device *dev = ag->dev;
struct ag71xx_ring *ring = &ag->rx_ring;
+ int offset = ag71xx_buffer_offset(ag);
int done = 0;
DBG("%s: rx packets, limit=%d, curr=%u, dirty=%u\n",
@@ -885,18 +881,25 @@ static int ag71xx_rx_packets(struct ag71xx *ag, int limit)
ag71xx_wr(ag, AG71XX_REG_RX_STATUS, RX_STATUS_PR);
- skb = ring->buf[i].skb;
pktlen = ag71xx_desc_pktlen(desc);
pktlen -= ETH_FCS_LEN;
dma_unmap_single(&dev->dev, ring->buf[i].dma_addr,
- AG71XX_RX_PKT_SIZE, DMA_FROM_DEVICE);
+ AG71XX_RX_BUF_SIZE, DMA_FROM_DEVICE);
dev->last_rx = jiffies;
dev->stats.rx_packets++;
dev->stats.rx_bytes += pktlen;
+ skb = build_skb(ring->buf[i].rx_buf);
+ if (!skb) {
+ kfree(ring->buf[i].rx_buf);
+ goto next;
+ }
+
+ skb_reserve(skb, offset);
skb_put(skb, pktlen);
+
if (ag71xx_has_ar8216(ag))
err = ag71xx_remove_ar8216_header(ag, skb, pktlen);
@@ -910,7 +913,8 @@ static int ag71xx_rx_packets(struct ag71xx *ag, int limit)
netif_receive_skb(skb);
}
- ring->buf[i].skb = NULL;
+next:
+ ring->buf[i].rx_buf = NULL;
done++;
ring->curr++;
@@ -944,7 +948,7 @@ static int ag71xx_poll(struct napi_struct *napi, int limit)
ag71xx_debugfs_update_napi_stats(ag, rx_done, tx_done);
rx_ring = &ag->rx_ring;
- if (rx_ring->buf[rx_ring->dirty % rx_ring->size].skb == NULL)
+ if (rx_ring->buf[rx_ring->dirty % rx_ring->size].rx_buf == NULL)
goto oom;
status = ag71xx_rr(ag, AG71XX_REG_RX_STATUS);