Re: [PATCH 1/3] net: lpc_eth: Replace WARN() trace with simple pr_warn()

Roland Stigge
2012-06-13T09:28:14Z

On 06/13/2012 08:16 AM, Eric Dumazet wrote:
> On Mon, 2012-06-11 at 21:18 +0200, Eric Dumazet wrote:
>> On Mon, 2012-06-11 at 11:26 +0200, Roland Stigge wrote:
>>
>>> Is it sensible at this point to increase the TX buffers anyway? For
>>> different reasons of course: We have enough SRAM available and TX
>>> buffers (16->32) are still more than RX buffers (48).
>>
>> I doubt it has any impact on performance for a 100Mbit link ?
>>
>> One thing that could be done would be to free skbs in
>> lpc_eth_hard_start_xmit() instead of __lpc_handle_xmit()
>>
>
> Here is the patch I was thinking about
>
> (on top of latest net-next)
>
> Could you please test it ?
>
> drivers/net/ethernet/nxp/lpc_eth.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/net/ethernet/nxp/lpc_eth.c b/drivers/net/ethernet/nxp/lpc_eth.c
> index 083d671..426f14c 100644
> --- a/drivers/net/ethernet/nxp/lpc_eth.c
> +++ b/drivers/net/ethernet/nxp/lpc_eth.c
> @@ -440,7 +440,7 @@ struct netdata_local {
> spinlock_t lock;
> void __iomem *net_base;
> u32 msg_enable;
> - struct sk_buff *skb[ENET_TX_DESC];
> + unsigned int skblen[ENET_TX_DESC];
> unsigned int last_tx_idx;
> unsigned int num_used_tx_buffs;
> struct mii_bus *mii_bus;
> @@ -908,7 +908,7 @@ static void __lpc_handle_xmit(struct net_device *ndev)
>
> txcidx = readl(LPC_ENET_TXCONSUMEINDEX(pldat->net_base));
> while (pldat->last_tx_idx != txcidx) {
> - skb = pldat->skb[pldat->last_tx_idx];
> + unsigned int skblen = pldat->skblen[pldat->last_tx_idx];
>
> /* A buffer is available, get buffer status */
> ptxstat = &pldat->tx_stat_v[pldat->last_tx_idx];
> @@ -945,9 +945,8 @@ static void __lpc_handle_xmit(struct net_device *ndev)
> } else {
> /* Update stats */
> ndev->stats.tx_packets++;
> - ndev->stats.tx_bytes += skb->len;
> + ndev->stats.tx_bytes += skblen;
> }
> - dev_kfree_skb_irq(skb);
>
> txcidx = readl(LPC_ENET_TXCONSUMEINDEX(pldat->net_base));
> }
> @@ -1132,7 +1131,7 @@ static int lpc_eth_hard_start_xmit(struct sk_buff *skb, struct net_device *ndev)
> memcpy(pldat->tx_buff_v + txidx * ENET_MAXF_SIZE, skb->data, len);
>
> /* Save the buffer and increment the buffer counter */
> - pldat->skb[txidx] = skb;
> + pldat->skblen[txidx] = len;
> pldat->num_used_tx_buffs++;
>
> /* Start transmit */
> @@ -1147,6 +1146,7 @@ static int lpc_eth_hard_start_xmit(struct sk_buff *skb, struct net_device *ndev)
>
> spin_unlock_irq(&pldat->lock);
>
> + dev_kfree_skb(skb);
> return NETDEV_TX_OK;
> }

Works fine for a while now.

We can remove the unused variable skb from __lpc_handle_xmit() now,
maybe just do in your patch?

Thanks!

Tested-by: Roland Stigge <stigge@antcom.de>