[PATCH v2] net: stmmac: add BQL support
From: Beniamino Galvani <hidden>
Date: 2015-01-21 18:08:34
Also in:
lkml
Subsystem:
networking drivers, stmmac ethernet driver, the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Maxime Chevallier, Linus Torvalds
Add support for Byte Queue Limits to the STMicro MAC driver. Tested on a Amlogic S802 quad Cortex-A9 board, where the use of BQL decreases the latency of a high priority ping from ~12ms to ~1ms when the 100Mbit link is saturated by 20 TCP streams. Signed-off-by: Beniamino Galvani <redacted> --- Changes since v1: - don't access skb->len after the start of DMA transmission in stmmac_xmit(), to avoid potential use after free in case tx_lock is removed in the future drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 118a427..1d74313 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c@@ -1097,6 +1097,7 @@ static int init_dma_desc_rings(struct net_device *dev, gfp_t flags) priv->dirty_tx = 0; priv->cur_tx = 0; + netdev_reset_queue(priv->dev); stmmac_clear_descriptors(priv);
@@ -1300,6 +1301,7 @@ static void stmmac_dma_operation_mode(struct stmmac_priv *priv) static void stmmac_tx_clean(struct stmmac_priv *priv) { unsigned int txsize = priv->dma_tx_size; + unsigned int bytes_compl = 0, pkts_compl = 0; spin_lock(&priv->tx_lock);
@@ -1356,6 +1358,8 @@ static void stmmac_tx_clean(struct stmmac_priv *priv) priv->hw->mode->clean_desc3(priv, p); if (likely(skb != NULL)) { + pkts_compl++; + bytes_compl += skb->len; dev_consume_skb_any(skb); priv->tx_skbuff[entry] = NULL; }
@@ -1364,6 +1368,9 @@ static void stmmac_tx_clean(struct stmmac_priv *priv) priv->dirty_tx++; } + + netdev_completed_queue(priv->dev, pkts_compl, bytes_compl); + if (unlikely(netif_queue_stopped(priv->dev) && stmmac_tx_avail(priv) > STMMAC_TX_THRESH(priv))) { netif_tx_lock(priv->dev);
@@ -1418,6 +1425,7 @@ static void stmmac_tx_err(struct stmmac_priv *priv) (i == txsize - 1)); priv->dirty_tx = 0; priv->cur_tx = 0; + netdev_reset_queue(priv->dev); priv->hw->dma->start_tx(priv->ioaddr); priv->dev->stats.tx_errors++;
@@ -2048,6 +2056,7 @@ static netdev_tx_t stmmac_xmit(struct sk_buff *skb, struct net_device *dev) if (!priv->hwts_tx_en) skb_tx_timestamp(skb); + netdev_sent_queue(dev, skb->len); priv->hw->dma->enable_dma_transmission(priv->ioaddr); spin_unlock(&priv->tx_lock);
--
2.1.4