From 120e87f91e2980e17356f96055023681f1a4d45b Mon Sep 17 00:00:00 2001 From: Giuseppe Cavallaro Date: Mon, 29 Feb 2016 14:27:42 +0100 Subject: [PATCH] stmmac: tune rx copy via threshold. There is a threshold now used to also limit the skb allocation when use zero-copy. This is to avoid that there are incoherence in the ring due to a failure on skb allocation under very aggressive testing and under low memory conditions. Signed-off-by: Giuseppe Cavallaro Signed-off-by: Alexandre TORGUE Signed-off-by: David S. Miller --- drivers/net/ethernet/stmicro/stmmac/stmmac.h | 1 + .../net/ethernet/stmicro/stmmac/stmmac_main.c | 26 +++++++++++++++++-- 2 files changed, 25 insertions(+), 2 deletions(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac.h b/drivers/net/ethernet/stmicro/stmmac/stmmac.h index 221f5cda70f3..d6c244f70171 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h @@ -75,6 +75,7 @@ struct stmmac_priv { unsigned int dirty_rx; unsigned int dma_buf_sz; unsigned int rx_copybreak; + unsigned int rx_zeroc_thresh; u32 rx_riwt; int hwts_rx_en; dma_addr_t *rx_skbuff_dma; diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 2ffe8dd9ce99..4c5ce9848ca9 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -72,6 +72,7 @@ module_param(phyaddr, int, S_IRUGO); MODULE_PARM_DESC(phyaddr, "Physical device address"); #define STMMAC_TX_THRESH (DMA_TX_SIZE / 4) +#define STMMAC_RX_THRESH (DMA_RX_SIZE / 4) static int flow_ctrl = FLOW_OFF; module_param(flow_ctrl, int, S_IRUGO | S_IWUSR); @@ -2138,6 +2139,14 @@ static void stmmac_rx_vlan(struct net_device *dev, struct sk_buff *skb) } +static inline int stmmac_rx_threshold_count(struct stmmac_priv *priv) +{ + if (priv->rx_zeroc_thresh < STMMAC_RX_THRESH) + return 0; + + return 1; +} + /** * stmmac_rx_refill - refill used skb preallocated buffers * @priv: driver private structure @@ -2162,8 +2171,15 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv) struct sk_buff *skb; skb = netdev_alloc_skb_ip_align(priv->dev, bfsize); - if (unlikely(!skb)) + if (unlikely(!skb)) { + /* so for a while no zero-copy! */ + priv->rx_zeroc_thresh = STMMAC_RX_THRESH; + if (unlikely(net_ratelimit())) + dev_err(priv->device, + "fail to alloc skb entry %d\n", + entry); break; + } priv->rx_skbuff[entry] = skb; priv->rx_skbuff_dma[entry] = @@ -2179,9 +2195,13 @@ static inline void stmmac_rx_refill(struct stmmac_priv *priv) priv->hw->mode->refill_desc3(priv, p); + if (priv->rx_zeroc_thresh > 0) + priv->rx_zeroc_thresh--; + if (netif_msg_rx_status(priv)) pr_debug("\trefill entry #%d\n", entry); } + wmb(); priv->hw->desc->set_rx_owner(p); wmb(); @@ -2285,7 +2305,8 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit) frame_len, status); } - if (unlikely(frame_len < priv->rx_copybreak)) { + if (unlikely((frame_len < priv->rx_copybreak) || + stmmac_rx_threshold_count(priv))) { skb = netdev_alloc_skb_ip_align(priv->dev, frame_len); if (unlikely(!skb)) { @@ -2320,6 +2341,7 @@ static int stmmac_rx(struct stmmac_priv *priv, int limit) } prefetch(skb->data - NET_IP_ALIGN); priv->rx_skbuff[entry] = NULL; + priv->rx_zeroc_thresh++; skb_put(skb, frame_len); dma_unmap_single(priv->device, -- 2.30.2