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Commit 6f0333b8 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

r8169: use 50% less ram for RX ring 



Using standard skb allocations in r8169 leads to order-3 allocations (if
PAGE_SIZE=4096), because NIC needs 16383 bytes, and skb overhead makes
this bigger than 16384 -> 32768 bytes per "skb"

Using kmalloc() permits to reduce memory requirements of one r8169 nic
by 4Mbytes. (256 frames * 16Kbytes). This is fine since a hardware bug
requires us to copy incoming frames, so we build real skb when doing
this copy.

Signed-off-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 7662ff46

drivers/net/r8169.c

+64 −119
Original line number Diff line number Diff line
@@ -187,12 +187,7 @@ static DEFINE_PCI_DEVICE_TABLE(rtl8169_pci_tbl) = { 


MODULE_DEVICE_TABLE(pci, rtl8169_pci_tbl);



/*

 * we set our copybreak very high so that we don't have

 * to allocate 16k frames all the time (see note in

 * rtl8169_open()

 */

static int rx_copybreak = 16383;

static int rx_buf_sz = 16383;

static int use_dac;

static struct {

	u32 msg_enable;
@@ -484,10 +479,8 @@ struct rtl8169_private { 
	struct RxDesc *RxDescArray;	/* 256-aligned Rx descriptor ring */

	dma_addr_t TxPhyAddr;

	dma_addr_t RxPhyAddr;

	struct sk_buff *Rx_skbuff[NUM_RX_DESC];	/* Rx data buffers */

	void *Rx_databuff[NUM_RX_DESC];	/* Rx data buffers */

	struct ring_info tx_skb[NUM_TX_DESC];	/* Tx data buffers */

	unsigned align;

	unsigned rx_buf_sz;

	struct timer_list timer;

	u16 cp_cmd;

	u16 intr_event;
@@ -515,8 +508,6 @@ struct rtl8169_private { 


MODULE_AUTHOR("Realtek and the Linux r8169 crew <netdev@vger.kernel.org>");

MODULE_DESCRIPTION("RealTek RTL-8169 Gigabit Ethernet driver");

module_param(rx_copybreak, int, 0);

MODULE_PARM_DESC(rx_copybreak, "Copy breakpoint for copy-only-tiny-frames");

module_param(use_dac, int, 0);

MODULE_PARM_DESC(use_dac, "Enable PCI DAC. Unsafe on 32 bit PCI slot.");

module_param_named(debug, debug.msg_enable, int, 0);
@@ -3196,7 +3187,6 @@ rtl8169_init_one(struct pci_dev *pdev, const struct pci_device_id *ent) 
	dev->features |= NETIF_F_GRO;



	tp->intr_mask = 0xffff;

	tp->align = cfg->align;

	tp->hw_start = cfg->hw_start;

	tp->intr_event = cfg->intr_event;

	tp->napi_event = cfg->napi_event;
@@ -3266,18 +3256,6 @@ static void __devexit rtl8169_remove_one(struct pci_dev *pdev) 
	pci_set_drvdata(pdev, NULL);

}



static void rtl8169_set_rxbufsize(struct rtl8169_private *tp,

				  unsigned int mtu)

{

	unsigned int max_frame = mtu + VLAN_ETH_HLEN + ETH_FCS_LEN;



	if (max_frame != 16383)

		printk(KERN_WARNING PFX "WARNING! Changing of MTU on this "

			"NIC may lead to frame reception errors!\n");



	tp->rx_buf_sz = (max_frame > RX_BUF_SIZE) ? max_frame : RX_BUF_SIZE;

}



static int rtl8169_open(struct net_device *dev)

{

	struct rtl8169_private *tp = netdev_priv(dev);
@@ -3286,18 +3264,6 @@ static int rtl8169_open(struct net_device *dev) 


	pm_runtime_get_sync(&pdev->dev);



	/*

	 * Note that we use a magic value here, its wierd I know

	 * its done because, some subset of rtl8169 hardware suffers from

	 * a problem in which frames received that are longer than

	 * the size set in RxMaxSize register return garbage sizes

	 * when received.  To avoid this we need to turn off filtering,

	 * which is done by setting a value of 16383 in the RxMaxSize register

	 * and allocating 16k frames to handle the largest possible rx value

	 * thats what the magic math below does.

	 */

	rtl8169_set_rxbufsize(tp, 16383 - VLAN_ETH_HLEN - ETH_FCS_LEN);



	/*

	 * Rx and Tx desscriptors needs 256 bytes alignment.

	 * dma_alloc_coherent provides more.
@@ -3474,7 +3440,7 @@ static void rtl_hw_start_8169(struct net_device *dev) 


	RTL_W8(EarlyTxThres, EarlyTxThld);



	rtl_set_rx_max_size(ioaddr, tp->rx_buf_sz);

	rtl_set_rx_max_size(ioaddr, rx_buf_sz);



	if ((tp->mac_version == RTL_GIGA_MAC_VER_01) ||

	    (tp->mac_version == RTL_GIGA_MAC_VER_02) ||
@@ -3735,7 +3701,7 @@ static void rtl_hw_start_8168(struct net_device *dev) 


	RTL_W8(EarlyTxThres, EarlyTxThld);



	rtl_set_rx_max_size(ioaddr, tp->rx_buf_sz);

	rtl_set_rx_max_size(ioaddr, rx_buf_sz);



	tp->cp_cmd |= RTL_R16(CPlusCmd) | PktCntrDisable | INTT_1;
@@ -3915,7 +3881,7 @@ static void rtl_hw_start_8101(struct net_device *dev) 


	RTL_W8(EarlyTxThres, EarlyTxThld);



	rtl_set_rx_max_size(ioaddr, tp->rx_buf_sz);

	rtl_set_rx_max_size(ioaddr, rx_buf_sz);



	tp->cp_cmd |= rtl_rw_cpluscmd(ioaddr) | PCIMulRW;
@@ -3956,8 +3922,6 @@ static int rtl8169_change_mtu(struct net_device *dev, int new_mtu) 


	rtl8169_down(dev);



	rtl8169_set_rxbufsize(tp, dev->mtu);



	ret = rtl8169_init_ring(dev);

	if (ret < 0)

		goto out;
@@ -3978,15 +3942,15 @@ static inline void rtl8169_make_unusable_by_asic(struct RxDesc *desc) 
	desc->opts1 &= ~cpu_to_le32(DescOwn | RsvdMask);

}



static void rtl8169_free_rx_skb(struct rtl8169_private *tp,

				struct sk_buff **sk_buff, struct RxDesc *desc)

static void rtl8169_free_rx_databuff(struct rtl8169_private *tp,

				     void **data_buff, struct RxDesc *desc)

{

	struct pci_dev *pdev = tp->pci_dev;



	dma_unmap_single(&pdev->dev, le64_to_cpu(desc->addr), tp->rx_buf_sz,

	dma_unmap_single(&pdev->dev, le64_to_cpu(desc->addr), rx_buf_sz,

			 PCI_DMA_FROMDEVICE);

	dev_kfree_skb(*sk_buff);

	*sk_buff = NULL;

	kfree(*data_buff);

	*data_buff = NULL;

	rtl8169_make_unusable_by_asic(desc);

}
@@ -4005,33 +3969,34 @@ static inline void rtl8169_map_to_asic(struct RxDesc *desc, dma_addr_t mapping, 
	rtl8169_mark_to_asic(desc, rx_buf_sz);

}



static struct sk_buff *rtl8169_alloc_rx_skb(struct pci_dev *pdev,

static inline void *rtl8169_align(void *data)

{

	return (void *)ALIGN((long)data, 16);

}



static struct sk_buff *rtl8169_alloc_rx_data(struct pci_dev *pdev,

					    struct net_device *dev,

					    struct RxDesc *desc, int rx_buf_sz,

					    unsigned int align, gfp_t gfp)

					    struct RxDesc *desc)

{

	struct sk_buff *skb;

	void *data;

	dma_addr_t mapping;

	unsigned int pad;

	int node = dev->dev.parent ? dev_to_node(dev->dev.parent) : -1;



	pad = align ? align : NET_IP_ALIGN;



	skb = __netdev_alloc_skb(dev, rx_buf_sz + pad, gfp);

	if (!skb)

		goto err_out;

	data = kmalloc_node(rx_buf_sz, GFP_KERNEL, node);

	if (!data)

		return NULL;



	skb_reserve(skb, align ? ((pad - 1) & (unsigned long)skb->data) : pad);



	mapping = dma_map_single(&pdev->dev, skb->data, rx_buf_sz,

	if (rtl8169_align(data) != data) {

		kfree(data);

		data = kmalloc_node(rx_buf_sz + 15, GFP_KERNEL, node);

		if (!data)

			return NULL;

	}

	mapping = dma_map_single(&pdev->dev, rtl8169_align(data), rx_buf_sz,

				 PCI_DMA_FROMDEVICE);



	rtl8169_map_to_asic(desc, mapping, rx_buf_sz);

out:

	return skb;



err_out:

	rtl8169_make_unusable_by_asic(desc);

	goto out;

	return data;

}



static void rtl8169_rx_clear(struct rtl8169_private *tp)
@@ -4039,8 +4004,8 @@ static void rtl8169_rx_clear(struct rtl8169_private *tp) 
	unsigned int i;



	for (i = 0; i < NUM_RX_DESC; i++) {

		if (tp->Rx_skbuff[i]) {

			rtl8169_free_rx_skb(tp, tp->Rx_skbuff + i,

		if (tp->Rx_databuff[i]) {

			rtl8169_free_rx_databuff(tp, tp->Rx_databuff + i,

					    tp->RxDescArray + i);

		}

	}
@@ -4052,21 +4017,21 @@ static u32 rtl8169_rx_fill(struct rtl8169_private *tp, struct net_device *dev, 
	u32 cur;



	for (cur = start; end - cur != 0; cur++) {

		struct sk_buff *skb;

		void *data;

		unsigned int i = cur % NUM_RX_DESC;



		WARN_ON((s32)(end - cur) < 0);



		if (tp->Rx_skbuff[i])

		if (tp->Rx_databuff[i])

			continue;



		skb = rtl8169_alloc_rx_skb(tp->pci_dev, dev,

					   tp->RxDescArray + i,

					   tp->rx_buf_sz, tp->align, gfp);

		if (!skb)

		data = rtl8169_alloc_rx_data(tp->pci_dev, dev,

					     tp->RxDescArray + i);

		if (!data) {

			rtl8169_make_unusable_by_asic(tp->RxDescArray + i);

			break;



		tp->Rx_skbuff[i] = skb;

		}

		tp->Rx_databuff[i] = data;

	}

	return cur - start;

}
@@ -4088,7 +4053,7 @@ static int rtl8169_init_ring(struct net_device *dev) 
	rtl8169_init_ring_indexes(tp);



	memset(tp->tx_skb, 0x0, NUM_TX_DESC * sizeof(struct ring_info));

	memset(tp->Rx_skbuff, 0x0, NUM_RX_DESC * sizeof(struct sk_buff *));

	memset(tp->Rx_databuff, 0x0, NUM_RX_DESC * sizeof(void *));



	if (rtl8169_rx_fill(tp, dev, 0, NUM_RX_DESC, GFP_KERNEL) != NUM_RX_DESC)

		goto err_out;
@@ -4473,27 +4438,23 @@ static inline void rtl8169_rx_csum(struct sk_buff *skb, u32 opts1) 
		skb_checksum_none_assert(skb);

}



static inline bool rtl8169_try_rx_copy(struct sk_buff **sk_buff,

				       struct rtl8169_private *tp, int pkt_size,

static struct sk_buff *rtl8169_try_rx_copy(void *data,

					   struct rtl8169_private *tp,

					   int pkt_size,

					   dma_addr_t addr)

{

	struct sk_buff *skb;

	bool done = false;



	if (pkt_size >= rx_copybreak)

		goto out;



	skb = netdev_alloc_skb_ip_align(tp->dev, pkt_size);

	if (!skb)

		goto out;



	data = rtl8169_align(data);

	dma_sync_single_for_cpu(&tp->pci_dev->dev, addr, pkt_size,

				PCI_DMA_FROMDEVICE);

	skb_copy_from_linear_data(*sk_buff, skb->data, pkt_size);

	*sk_buff = skb;

	done = true;

out:

	return done;

	prefetch(data);

	skb = netdev_alloc_skb_ip_align(tp->dev, pkt_size);

	if (skb)

		memcpy(skb->data, data, pkt_size);

	dma_sync_single_for_device(&tp->pci_dev->dev, addr, pkt_size,

				   PCI_DMA_FROMDEVICE);

	return skb;

}



/*
@@ -4508,7 +4469,7 @@ static int rtl8169_rx_interrupt(struct net_device *dev, 
				void __iomem *ioaddr, u32 budget)

{

	unsigned int cur_rx, rx_left;

	unsigned int delta, count;

	unsigned int count;

	int polling = (budget != ~(u32)0) ? 1 : 0;



	cur_rx = tp->cur_rx;
@@ -4537,12 +4498,11 @@ static int rtl8169_rx_interrupt(struct net_device *dev, 
				rtl8169_schedule_work(dev, rtl8169_reset_task);

				dev->stats.rx_fifo_errors++;

			}

			rtl8169_mark_to_asic(desc, tp->rx_buf_sz);

			rtl8169_mark_to_asic(desc, rx_buf_sz);

		} else {

			struct sk_buff *skb = tp->Rx_skbuff[entry];

			struct sk_buff *skb;

			dma_addr_t addr = le64_to_cpu(desc->addr);

			int pkt_size = (status & 0x00001FFF) - 4;

			struct pci_dev *pdev = tp->pci_dev;



			/*

			 * The driver does not support incoming fragmented
@@ -4552,18 +4512,16 @@ static int rtl8169_rx_interrupt(struct net_device *dev, 
			if (unlikely(rtl8169_fragmented_frame(status))) {

				dev->stats.rx_dropped++;

				dev->stats.rx_length_errors++;

				rtl8169_mark_to_asic(desc, tp->rx_buf_sz);

				rtl8169_mark_to_asic(desc, rx_buf_sz);

				continue;

			}



			if (rtl8169_try_rx_copy(&skb, tp, pkt_size, addr)) {

				dma_sync_single_for_device(&pdev->dev, addr,

					pkt_size, PCI_DMA_FROMDEVICE);

				rtl8169_mark_to_asic(desc, tp->rx_buf_sz);

			} else {

				dma_unmap_single(&pdev->dev, addr, tp->rx_buf_sz,

						 PCI_DMA_FROMDEVICE);

				tp->Rx_skbuff[entry] = NULL;

			skb = rtl8169_try_rx_copy(tp->Rx_databuff[entry],

						  tp, pkt_size, addr);

			rtl8169_mark_to_asic(desc, rx_buf_sz);

			if (!skb) {

				dev->stats.rx_dropped++;

				continue;

			}



			rtl8169_rx_csum(skb, status);
@@ -4592,20 +4550,7 @@ static int rtl8169_rx_interrupt(struct net_device *dev, 
	count = cur_rx - tp->cur_rx;

	tp->cur_rx = cur_rx;



	delta = rtl8169_rx_fill(tp, dev, tp->dirty_rx, tp->cur_rx, GFP_ATOMIC);

	if (!delta && count)

		netif_info(tp, intr, dev, "no Rx buffer allocated\n");

	tp->dirty_rx += delta;



	/*

	 * FIXME: until there is periodic timer to try and refill the ring,

	 * a temporary shortage may definitely kill the Rx process.

	 * - disable the asic to try and avoid an overflow and kick it again

	 *   after refill ?

	 * - how do others driver handle this condition (Uh oh...).

	 */

	if (tp->dirty_rx + NUM_RX_DESC == tp->cur_rx)

		netif_emerg(tp, intr, dev, "Rx buffers exhausted\n");

	tp->dirty_rx += count;



	return count;

}