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.cavall...@st.com>
---
drivers/net/ethernet/stmicro/stmmac/stmmac.h | 1 +
drivers/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 c94ae65..9c62b86 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac.h
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac.h
@@ -77,6 +77,7 @@ struct stmmac_priv {
unsigned int dma_rx_size;
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 b431046..71bda4e 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -201,6 +201,7 @@ static void print_pkt(unsigned char *buf, int len)
/* minimum number of free TX descriptors required to wake up TX process */
#define STMMAC_TX_THRESH(x) (x->dma_tx_size/4)
+#define STMMAC_RX_THRESH(x) (x->dma_rx_size / 4)
static inline u32 stmmac_tx_avail(struct stmmac_priv *priv)
{
@@ -2173,6 +2174,14 @@ 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(priv))
+ return 0;
+
+ return 1;
+}
+
/**
* stmmac_rx_refill - refill used skb preallocated buffers
* @priv: driver private structure
@@ -2198,8 +2207,15 @@ 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(priv);
+ 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] =
@@ -2215,9 +2231,13 @@ 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();
@@ -2322,7 +2342,8 @@ 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)) {
@@ -2357,6 +2378,7 @@ 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,
--
1.7.4.4
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