[net-next] r8169: add byte queue limit support.

Btw the stuff below and the 64bits stats overlap. Both could
go together.

From: Igor Maravic <igorm@etf.rs>
Date: Mon, 5 Mar 2012 00:01:25 +0100
Subject: [PATCH 2/2] r8169: add byte queue limit support.

Nothing fancy:
- sent bytes count is notified in the start_xmit path right before
  updating the owner bit in the hardware Tx descriptor (E. Dumazet)
- avoid useless tp->dev dereferencing in start_xmit (E. Dumazet)

Use of netdev_reset_queue is favored over proper accounting in
rtl8169_tx_clear_range since the latter would need more work for the
same result (nb: said accounting degenerates to nothing in xmit_frags).

Signed-off-by: Igor Maravic <igorm@etf.rs>
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
---
 drivers/net/ethernet/realtek/r8169.c |   27 ++++++++++++++++++++++-----
 1 files changed, 22 insertions(+), 5 deletions(-)

Le lundi 05 mars 2012 à 00:28 +0100, Francois Romieu a écrit :
> Btw the stuff below and the 64bits stats overlap. Both could
> go together.
> 
> From: Igor Maravic <igorm@etf.rs>
> Date: Mon, 5 Mar 2012 00:01:25 +0100
> Subject: [PATCH 2/2] r8169: add byte queue limit support.
> 
> Nothing fancy:
> - sent bytes count is notified in the start_xmit path right before
>   updating the owner bit in the hardware Tx descriptor (E. Dumazet)
> - avoid useless tp->dev dereferencing in start_xmit (E. Dumazet)
> 
> Use of netdev_reset_queue is favored over proper accounting in
> rtl8169_tx_clear_range since the latter would need more work for the
> same result (nb: said accounting degenerates to nothing in xmit_frags).
> 
> Signed-off-by: Igor Maravic <igorm@etf.rs>
> Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
> ---
>  drivers/net/ethernet/realtek/r8169.c |   27 ++++++++++++++++++++++-----
>  1 files changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
> index a4d7674..515a7ed 100644
> --- a/drivers/net/ethernet/realtek/r8169.c
> +++ b/drivers/net/ethernet/realtek/r8169.c
> @@ -5399,6 +5399,7 @@ static void rtl8169_tx_clear(struct rtl8169_private *tp)
>  {
>  	rtl8169_tx_clear_range(tp, tp->dirty_tx, NUM_TX_DESC);
>  	tp->cur_tx = tp->dirty_tx = 0;
> +	netdev_reset_queue(tp->dev);
>  }
>  
>  static void rtl_reset_work(struct rtl8169_private *tp)
> @@ -5553,6 +5554,8 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
>  
>  	txd->opts2 = cpu_to_le32(opts[1]);
>  
> +	netdev_sent_queue(dev, skb->len);
> +
>  	wmb();
>  
>  	/* Anti gcc 2.95.3 bugware (sic) */
> @@ -5647,9 +5650,16 @@ static void rtl8169_pcierr_interrupt(struct net_device *dev)
>  	rtl_schedule_task(tp, RTL_FLAG_TASK_RESET_PENDING);
>  }
>  
> +struct rtl_txc {
> +	int packets;
> +	int bytes;
> +};
> +
>  static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
>  {
> +	struct rtl8169_stats *tx_stats = &tp->tx_stats;
>  	unsigned int dirty_tx, tx_left;
> +	struct rtl_txc txc = { 0, 0 };
>  
>  	dirty_tx = tp->dirty_tx;
>  	smp_rmb();
> @@ -5668,17 +5678,24 @@ static void rtl_tx(struct net_device *dev, struct rtl8169_private *tp)
>  		rtl8169_unmap_tx_skb(&tp->pci_dev->dev, tx_skb,
>  				     tp->TxDescArray + entry);
>  		if (status & LastFrag) {
> -			u64_stats_update_begin(&tp->tx_stats.syncp);
> -			tp->tx_stats.packets++;
> -			tp->tx_stats.bytes += tx_skb->skb->len;
> -			u64_stats_update_end(&tp->tx_stats.syncp);
> -			dev_kfree_skb(tx_skb->skb);
> +			struct sk_buff *skb = tx_skb->skb;
> +
> +			txc.packets++;
> +			txc.bytes += skb->len;
> +			dev_kfree_skb(skb);
>  			tx_skb->skb = NULL;
>  		}
>  		dirty_tx++;
>  		tx_left--;
>  	}
>  
> +	u64_stats_update_begin(&tx_stats->syncp);
> +	tx_stats->packets += txc.packets;
> +	tx_stats->bytes += txc.bytes;
> +	u64_stats_update_end(&tx_stats->syncp);
> +
> +	netdev_completed_queue(dev, txc.packets, txc.bytes);
> +
>  	if (tp->dirty_tx != dirty_tx) {
>  		tp->dirty_tx = dirty_tx;
>  		/* Sync with rtl8169_start_xmit:

Acked-by: Eric Dumazet <eric.dumazet@gmail.com>

By the way, the "From: Igor Maravic <igorm@etf.rs>" should be the very
first line of your mail, as mentioned in Documentation/SubmittingPatches
(around line 543). 

Otherwise, risk is that "Author" attribution might be you instead of
Igor (but the Signed-off-by order will be ok)



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Eric Dumazet <eric.dumazet@gmail.com> :
[...]
> By the way, the "From: Igor Maravic <igorm@etf.rs>" should be the very
> first line of your mail, as mentioned in Documentation/SubmittingPatches
> (around line 543). 
> 
> Otherwise, risk is that "Author" attribution might be you instead of
> Igor (but the Signed-off-by order will be ok)

I'll do a formal submission on monday evening. It only was a heads up
as things conflicted and I had to modify Igor's patch.

Thanks for the (re-)reminder anyway.