igb: drop support for single buffer mode

This change removes support for single buffer mode from igb and makes the
driver function in packet split always.  The advantage to doing this is
that we can reduce total memory allocation overhead significantly as we
will only need to allocate one 1K slab per packet and then make use of a
reusable half page instead of allocating a 2K slab per packet.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by:  Aaron Brown  <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

drivers/net/ethernet/intel/igb/igb.h

@@ -111,11 +111,9 @@ struct vf_data_storage {
 #define MAXIMUM_ETHERNET_VLAN_SIZE 1522
 
 /* Supported Rx Buffer Sizes */
-#define IGB_RXBUFFER_64    64     /* Used for packet split */
-#define IGB_RXBUFFER_128   128    /* Used for packet split */
-#define IGB_RXBUFFER_1024  1024
-#define IGB_RXBUFFER_2048  2048
+#define IGB_RXBUFFER_512   512
 #define IGB_RXBUFFER_16384 16384
+#define IGB_RX_HDR_LEN     IGB_RXBUFFER_512
 
 /* How many Tx Descriptors do we need to call netif_wake_queue ? */
 #define IGB_TX_QUEUE_WAKE	16
@@ -221,7 +219,6 @@ struct igb_ring {
 		struct {
 			struct igb_rx_queue_stats rx_stats;
 			struct u64_stats_sync rx_syncp;
-			u32 rx_buffer_len;
 		};
 	};
 };

drivers/net/ethernet/intel/igb/igb_ethtool.c

@@ -1368,7 +1368,6 @@ static int igb_setup_desc_rings(struct igb_adapter *adapter)
 	rx_ring->count = IGB_DEFAULT_RXD;
 	rx_ring->dev = &adapter->pdev->dev;
 	rx_ring->netdev = adapter->netdev;
-	rx_ring->rx_buffer_len = IGB_RXBUFFER_2048;
 	rx_ring->reg_idx = adapter->vfs_allocated_count;
 
 	if (igb_setup_rx_resources(rx_ring)) {
@@ -1597,7 +1596,7 @@ static int igb_clean_test_rings(struct igb_ring *rx_ring,
 		/* unmap rx buffer, will be remapped by alloc_rx_buffers */
 		dma_unmap_single(rx_ring->dev,
 		                 buffer_info->dma,
-				 rx_ring->rx_buffer_len,
+				 IGB_RX_HDR_LEN,
 				 DMA_FROM_DEVICE);
 		buffer_info->dma = 0;
 
@@ -1635,7 +1634,7 @@ static int igb_run_loopback_test(struct igb_adapter *adapter)
 	struct igb_ring *tx_ring = &adapter->test_tx_ring;
 	struct igb_ring *rx_ring = &adapter->test_rx_ring;
 	int i, j, lc, good_cnt, ret_val = 0;
-	unsigned int size = 1024;
+	unsigned int size = IGB_RX_HDR_LEN;
 	netdev_tx_t tx_ret_val;
 	struct sk_buff *skb;
 

drivers/net/ethernet/intel/igb/igb_main.c

@@ -517,16 +517,14 @@ rx_ring_summary:
 						DUMP_PREFIX_ADDRESS,
 						16, 1,
 						phys_to_virt(buffer_info->dma),
-						rx_ring->rx_buffer_len, true);
-					if (rx_ring->rx_buffer_len
-						< IGB_RXBUFFER_1024)
-						print_hex_dump(KERN_INFO, "",
-						  DUMP_PREFIX_ADDRESS,
-						  16, 1,
-						  phys_to_virt(
-						    buffer_info->page_dma +
-						    buffer_info->page_offset),
-						  PAGE_SIZE/2, true);
+						IGB_RX_HDR_LEN, true);
+					print_hex_dump(KERN_INFO, "",
+					  DUMP_PREFIX_ADDRESS,
+					  16, 1,
+					  phys_to_virt(
+					    buffer_info->page_dma +
+					    buffer_info->page_offset),
+					  PAGE_SIZE/2, true);
 				}
 			}
 
@@ -707,7 +705,6 @@ static int igb_alloc_queues(struct igb_adapter *adapter)
 		ring->queue_index = i;
 		ring->dev = &adapter->pdev->dev;
 		ring->netdev = adapter->netdev;
-		ring->rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE;
 		ring->flags = IGB_RING_FLAG_RX_CSUM; /* enable rx checksum */
 		/* set flag indicating ring supports SCTP checksum offload */
 		if (adapter->hw.mac.type >= e1000_82576)
@@ -3049,22 +3046,13 @@ void igb_configure_rx_ring(struct igb_adapter *adapter,
 	writel(0, ring->tail);
 
 	/* set descriptor configuration */
-	if (ring->rx_buffer_len < IGB_RXBUFFER_1024) {
-		srrctl = ALIGN(ring->rx_buffer_len, 64) <<
-		         E1000_SRRCTL_BSIZEHDRSIZE_SHIFT;
+	srrctl = IGB_RX_HDR_LEN << E1000_SRRCTL_BSIZEHDRSIZE_SHIFT;
 #if (PAGE_SIZE / 2) > IGB_RXBUFFER_16384
-		srrctl |= IGB_RXBUFFER_16384 >>
-		          E1000_SRRCTL_BSIZEPKT_SHIFT;
+	srrctl |= IGB_RXBUFFER_16384 >> E1000_SRRCTL_BSIZEPKT_SHIFT;
 #else
-		srrctl |= (PAGE_SIZE / 2) >>
-		          E1000_SRRCTL_BSIZEPKT_SHIFT;
+	srrctl |= (PAGE_SIZE / 2) >> E1000_SRRCTL_BSIZEPKT_SHIFT;
 #endif
-		srrctl |= E1000_SRRCTL_DESCTYPE_HDR_SPLIT_ALWAYS;
-	} else {
-		srrctl = ALIGN(ring->rx_buffer_len, 1024) >>
-		         E1000_SRRCTL_BSIZEPKT_SHIFT;
-		srrctl |= E1000_SRRCTL_DESCTYPE_ADV_ONEBUF;
-	}
+	srrctl |= E1000_SRRCTL_DESCTYPE_HDR_SPLIT_ALWAYS;
 	if (hw->mac.type == e1000_82580)
 		srrctl |= E1000_SRRCTL_TIMESTAMP;
 	/* Only set Drop Enable if we are supporting multiple queues */
@@ -3268,7 +3256,7 @@ static void igb_clean_rx_ring(struct igb_ring *rx_ring)
 		if (buffer_info->dma) {
 			dma_unmap_single(rx_ring->dev,
 			                 buffer_info->dma,
-					 rx_ring->rx_buffer_len,
+					 IGB_RX_HDR_LEN,
 					 DMA_FROM_DEVICE);
 			buffer_info->dma = 0;
 		}
@@ -4466,7 +4454,6 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
 	struct igb_adapter *adapter = netdev_priv(netdev);
 	struct pci_dev *pdev = adapter->pdev;
 	int max_frame = new_mtu + ETH_HLEN + ETH_FCS_LEN + VLAN_HLEN;
-	u32 rx_buffer_len, i;
 
 	if ((new_mtu < 68) || (max_frame > MAX_JUMBO_FRAME_SIZE)) {
 		dev_err(&pdev->dev, "Invalid MTU setting\n");
@@ -4485,30 +4472,6 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
 	/* igb_down has a dependency on max_frame_size */
 	adapter->max_frame_size = max_frame;
 
-	/* NOTE: netdev_alloc_skb reserves 16 bytes, and typically NET_IP_ALIGN
-	 * means we reserve 2 more, this pushes us to allocate from the next
-	 * larger slab size.
-	 * i.e. RXBUFFER_2048 --> size-4096 slab
-	 */
-
-	if (adapter->hw.mac.type == e1000_82580)
-		max_frame += IGB_TS_HDR_LEN;
-
-	if (max_frame <= IGB_RXBUFFER_1024)
-		rx_buffer_len = IGB_RXBUFFER_1024;
-	else if (max_frame <= MAXIMUM_ETHERNET_VLAN_SIZE)
-		rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE;
-	else
-		rx_buffer_len = IGB_RXBUFFER_128;
-
-	if ((max_frame == ETH_FRAME_LEN + ETH_FCS_LEN + IGB_TS_HDR_LEN) ||
-	     (max_frame == MAXIMUM_ETHERNET_VLAN_SIZE + IGB_TS_HDR_LEN))
-		rx_buffer_len = MAXIMUM_ETHERNET_VLAN_SIZE + IGB_TS_HDR_LEN;
-
-	if ((adapter->hw.mac.type == e1000_82580) &&
-	    (rx_buffer_len == IGB_RXBUFFER_128))
-		rx_buffer_len += IGB_RXBUFFER_64;
-
 	if (netif_running(netdev))
 		igb_down(adapter);
 
@@ -4516,9 +4479,6 @@ static int igb_change_mtu(struct net_device *netdev, int new_mtu)
 		 netdev->mtu, new_mtu);
 	netdev->mtu = new_mtu;
 
-	for (i = 0; i < adapter->num_rx_queues; i++)
-		adapter->rx_ring[i]->rx_buffer_len = rx_buffer_len;
-
 	if (netif_running(netdev))
 		igb_up(adapter);
 	else
@@ -5781,8 +5741,7 @@ static void igb_rx_hwtstamp(struct igb_q_vector *q_vector, u32 staterr,
 
 	igb_systim_to_hwtstamp(adapter, skb_hwtstamps(skb), regval);
 }
-static inline u16 igb_get_hlen(struct igb_ring *rx_ring,
-                               union e1000_adv_rx_desc *rx_desc)
+static inline u16 igb_get_hlen(union e1000_adv_rx_desc *rx_desc)
 {
 	/* HW will not DMA in data larger than the given buffer, even if it
 	 * parses the (NFS, of course) header to be larger.  In that case, it
@@ -5790,8 +5749,8 @@ static inline u16 igb_get_hlen(struct igb_ring *rx_ring,
 	 */
 	u16 hlen = (le16_to_cpu(rx_desc->wb.lower.lo_dword.hdr_info) &
 	           E1000_RXDADV_HDRBUFLEN_MASK) >> E1000_RXDADV_HDRBUFLEN_SHIFT;
-	if (hlen > rx_ring->rx_buffer_len)
-		hlen = rx_ring->rx_buffer_len;
+	if (hlen > IGB_RX_HDR_LEN)
+		hlen = IGB_RX_HDR_LEN;
 	return hlen;
 }
 
@@ -5841,14 +5800,10 @@ static bool igb_clean_rx_irq_adv(struct igb_q_vector *q_vector,
 
 		if (buffer_info->dma) {
 			dma_unmap_single(dev, buffer_info->dma,
-					 rx_ring->rx_buffer_len,
+					 IGB_RX_HDR_LEN,
 					 DMA_FROM_DEVICE);
 			buffer_info->dma = 0;
-			if (rx_ring->rx_buffer_len >= IGB_RXBUFFER_1024) {
-				skb_put(skb, length);
-				goto send_up;
-			}
-			skb_put(skb, igb_get_hlen(rx_ring, rx_desc));
+			skb_put(skb, igb_get_hlen(rx_desc));
 		}
 
 		if (length) {
@@ -5879,7 +5834,7 @@ static bool igb_clean_rx_irq_adv(struct igb_q_vector *q_vector,
 			next_buffer->dma = 0;
 			goto next_desc;
 		}
-send_up:
+
 		if (staterr & E1000_RXDEXT_ERR_FRAME_ERR_MASK) {
 			dev_kfree_skb_irq(skb);
 			goto next_desc;
@@ -5943,17 +5898,14 @@ void igb_alloc_rx_buffers_adv(struct igb_ring *rx_ring, int cleaned_count)
 	struct igb_buffer *buffer_info;
 	struct sk_buff *skb;
 	unsigned int i;
-	int bufsz;
 
 	i = rx_ring->next_to_use;
 	buffer_info = &rx_ring->buffer_info[i];
 
-	bufsz = rx_ring->rx_buffer_len;
-
 	while (cleaned_count--) {
 		rx_desc = E1000_RX_DESC_ADV(*rx_ring, i);
 
-		if ((bufsz < IGB_RXBUFFER_1024) && !buffer_info->page_dma) {
+		if (!buffer_info->page_dma) {
 			if (!buffer_info->page) {
 				buffer_info->page = netdev_alloc_page(netdev);
 				if (unlikely(!buffer_info->page)) {
@@ -5983,7 +5935,7 @@ void igb_alloc_rx_buffers_adv(struct igb_ring *rx_ring, int cleaned_count)
 
 		skb = buffer_info->skb;
 		if (!skb) {
-			skb = netdev_alloc_skb_ip_align(netdev, bufsz);
+			skb = netdev_alloc_skb_ip_align(netdev, IGB_RX_HDR_LEN);
 			if (unlikely(!skb)) {
 				u64_stats_update_begin(&rx_ring->rx_syncp);
 				rx_ring->rx_stats.alloc_failed++;
@@ -5996,7 +5948,7 @@ void igb_alloc_rx_buffers_adv(struct igb_ring *rx_ring, int cleaned_count)
 		if (!buffer_info->dma) {
 			buffer_info->dma = dma_map_single(rx_ring->dev,
 			                                  skb->data,
-							  bufsz,
+							  IGB_RX_HDR_LEN,
 							  DMA_FROM_DEVICE);
 			if (dma_mapping_error(rx_ring->dev,
 					      buffer_info->dma)) {
@@ -6009,14 +5961,8 @@ void igb_alloc_rx_buffers_adv(struct igb_ring *rx_ring, int cleaned_count)
 		}
 		/* Refresh the desc even if buffer_addrs didn't change because
 		 * each write-back erases this info. */
-		if (bufsz < IGB_RXBUFFER_1024) {
-			rx_desc->read.pkt_addr =
-			     cpu_to_le64(buffer_info->page_dma);
-			rx_desc->read.hdr_addr = cpu_to_le64(buffer_info->dma);
-		} else {
-			rx_desc->read.pkt_addr = cpu_to_le64(buffer_info->dma);
-			rx_desc->read.hdr_addr = 0;
-		}
+		rx_desc->read.pkt_addr = cpu_to_le64(buffer_info->page_dma);
+		rx_desc->read.hdr_addr = cpu_to_le64(buffer_info->dma);
 
 		i++;
 		if (i == rx_ring->count)