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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 <peppe.cavallaro@st.com>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Giuseppe Cavallaro 2016-02-29 14:27:42 +01:00 committed by David S. Miller
parent 22ad383815
commit 120e87f91e
2 changed files with 25 additions and 2 deletions
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1
drivers/net/ethernet/stmicro/stmmac/stmmac.h
View File

@ -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;

26
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
View File

@ -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,