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

Francois Romieu
2012-03-04T23:28:58Z

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:
--
1.7.7.6