From: Mugunthan V N <mugunthanvnm@ti•com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix•de>
Cc: <netdev@vger•kernel.org>, <tglx@linutronix•de>,
"David S. Miller" <davem@davemloft•net>
Subject: Re: [PATCH 5/5] net/cpsw: redo rx skb allocation in rx path
Date: Thu, 18 Apr 2013 17:20:56 +0530 [thread overview]
Message-ID: <516FDE20.2050605@ti.com> (raw)
In-Reply-To: <1366235536-15744-6-git-send-email-bigeasy@linutronix.de>
On 4/18/2013 3:22 AM, Sebastian Andrzej Siewior wrote:
> In case that we run into OOM during the allocation of the new rx-skb we
> don't get one and we have one skb less than we used to have. If this
> continues to happen then we end up with no rx-skbs at all.
> This patch changes the following:
> - if we fail to allocate the new skb, then we treat the currently
> completed skb as the new one and so drop the currently received data.
> - instead of testing multiple times if the device is gone we rely one
> the status field which is set to -ENOSYS in case the channel is going
> down and incomplete requests are purged.
> cpdma_chan_stop() removes most of the packages with -ENOSYS. The
> currently active packet which is removed has the "tear down" bit set.
> So if that bit is set, we send ENOSYS as well otherwise we pass the
> status bits which are required to figure out which of the two possible
> just finished.
>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix•de>
> ---
> drivers/net/ethernet/ti/cpsw.c | 33 ++++++++++++-------------------
> drivers/net/ethernet/ti/davinci_cpdma.c | 7 ++++++-
> 2 files changed, 19 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/net/ethernet/ti/cpsw.c b/drivers/net/ethernet/ti/cpsw.c
> index 559b020..f684e9b 100644
> --- a/drivers/net/ethernet/ti/cpsw.c
> +++ b/drivers/net/ethernet/ti/cpsw.c
> @@ -469,43 +469,36 @@ void cpsw_tx_handler(void *token, int len, int status)
> void cpsw_rx_handler(void *token, int len, int status)
> {
> struct sk_buff *skb = token;
> + struct sk_buff *new_skb;
> struct net_device *ndev = skb->dev;
> struct cpsw_priv *priv = netdev_priv(ndev);
> int ret = 0;
>
> cpsw_dual_emac_src_port_detect(status, priv, ndev, skb);
>
> - /* free and bail if we are shutting down */
> - if (unlikely(!netif_running(ndev)) ||
> - unlikely(!netif_carrier_ok(ndev))) {
> + if (unlikely(status < 0)) {
> + /* the interface is going down, skbs are purged */
> dev_kfree_skb_any(skb);
> return;
> }
> - if (likely(status >= 0)) {
> +
> + new_skb = netdev_alloc_skb_ip_align(ndev, priv->rx_packet_max);
> + if (new_skb) {
> skb_put(skb, len);
> cpts_rx_timestamp(priv->cpts, skb);
> skb->protocol = eth_type_trans(skb, ndev);
> netif_receive_skb(skb);
> priv->stats.rx_bytes += len;
> priv->stats.rx_packets++;
> - skb = NULL;
> - }
> -
> - if (unlikely(!netif_running(ndev))) {
> - if (skb)
> - dev_kfree_skb_any(skb);
> - return;
> + } else {
> + priv->stats.rx_dropped++;
> + new_skb = skb;
Why you want to drop a successfully received packet as you memory alloc
failed?
Let the stack get it processed and there after you can continue with one
less
rx skb
> }
>
> - if (likely(!skb)) {
> - skb = netdev_alloc_skb_ip_align(ndev, priv->rx_packet_max);
> - if (WARN_ON(!skb))
> - return;
> -
> - ret = cpdma_chan_submit(priv->rxch, skb, skb->data,
> - skb_tailroom(skb), 0);
> - }
> - WARN_ON(ret < 0);
> + ret = cpdma_chan_submit(priv->rxch, new_skb, new_skb->data,
> + skb_tailroom(new_skb), 0);
> + if (WARN_ON(ret < 0))
> + dev_kfree_skb_any(new_skb);
> }
>
> static irqreturn_t cpsw_interrupt(int irq, void *dev_id)
> diff --git a/drivers/net/ethernet/ti/davinci_cpdma.c b/drivers/net/ethernet/ti/davinci_cpdma.c
> index 3cc20e7..6b0a89f 100644
> --- a/drivers/net/ethernet/ti/davinci_cpdma.c
> +++ b/drivers/net/ethernet/ti/davinci_cpdma.c
> @@ -776,6 +776,7 @@ static int __cpdma_chan_process(struct cpdma_chan *chan)
> struct cpdma_ctlr *ctlr = chan->ctlr;
> struct cpdma_desc __iomem *desc;
> int status, outlen;
> + int cb_status = 0;
> struct cpdma_desc_pool *pool = ctlr->pool;
> dma_addr_t desc_dma;
> unsigned long flags;
> @@ -811,8 +812,12 @@ static int __cpdma_chan_process(struct cpdma_chan *chan)
> }
>
> spin_unlock_irqrestore(&chan->lock, flags);
> + if (unlikely(status & CPDMA_DESC_TD_COMPLETE))
> + cb_status = -ENOSYS;
> + else
> + cb_status = status;
>
> - __cpdma_chan_free(chan, desc, outlen, status);
> + __cpdma_chan_free(chan, desc, outlen, cb_status);
> return status;
>
> unlock_ret:
Regards
Mugunthan V N
next prev parent reply other threads:[~2013-04-18 11:51 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-04-17 21:52 my small cpsw queue Sebastian Andrzej Siewior
2013-04-17 21:52 ` [PATCH 1/5] net/davinci_cpdma: don't check for jiffies with interrupts Sebastian Andrzej Siewior
2013-04-18 11:49 ` Mugunthan V N
2013-04-17 21:52 ` [PATCH 2/5] net/cpsw: don't continue if we miss to allocate rx skbs Sebastian Andrzej Siewior
2013-04-18 11:50 ` Mugunthan V N
2013-04-18 12:09 ` Sebastian Andrzej Siewior
2013-04-19 10:40 ` Mugunthan V N
2013-04-22 8:05 ` Sebastian Andrzej Siewior
2013-04-17 21:52 ` [PATCH 3/5] net/cpsw: don't rely on netif_running() to check which device is active Sebastian Andrzej Siewior
2013-04-18 11:50 ` Mugunthan V N
2013-04-18 12:10 ` Sebastian Andrzej Siewior
2013-04-19 10:35 ` Mugunthan V N
2013-04-22 8:30 ` [PATCH 3/5 v2] net/cpsw: don't rely only " Sebastian Andrzej Siewior
2013-04-22 9:14 ` Mugunthan V N
2013-04-22 9:30 ` Sebastian Andrzej Siewior
2013-04-22 9:40 ` Mugunthan V N
2013-04-22 9:49 ` Sebastian Andrzej Siewior
2013-04-22 10:12 ` Mugunthan V N
2013-04-22 10:19 ` Sebastian Andrzej Siewior
2013-04-22 19:21 ` David Miller
2013-04-19 13:10 ` [PATCH 3/5] net/cpsw: don't rely " Sergei Shtylyov
2013-04-22 8:33 ` Sebastian Andrzej Siewior
2013-04-17 21:52 ` [PATCH 4/5] net/davinci_cpdma: remove unused argument in cpdma_chan_submit() Sebastian Andrzej Siewior
2013-04-18 11:51 ` Mugunthan V N
2013-04-17 21:52 ` [PATCH 5/5] net/cpsw: redo rx skb allocation in rx path Sebastian Andrzej Siewior
2013-04-18 11:50 ` Mugunthan V N [this message]
2013-04-18 12:13 ` Sebastian Andrzej Siewior
2013-04-19 10:28 ` Mugunthan V N
2013-04-18 14:59 ` Eric Dumazet
-- strict thread matches above, loose matches on Subject: below --
2013-04-23 17:31 cpsw queue, v2 Sebastian Andrzej Siewior
2013-04-23 17:31 ` [PATCH 5/5] net/cpsw: redo rx skb allocation in rx path Sebastian Andrzej Siewior
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