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

Eric Dumazet
2012-03-04T23:39:12Z

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)