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Message-Id: <200911061835.24928.lgrijincu@ixiacom.com>
Date: Fri, 6 Nov 2009 18:35:24 +0200
From: Lucian Adrian Grijincu <lgrijincu@...acom.com>
To: Eric Dumazet <eric.dumazet@...il.com>
Cc: David Miller <davem@...emloft.net>, netdev@...r.kernel.org,
opurdila@...acom.com
Subject: Re: [PATCH net-next-2.6] udp: Optimise multicast reception
În data de Vin 06 Noi 2009 17:59:51 ați scris:
> +static void flush_stack(struct sock **stack, unsigned int count,
> + struct sk_buff *skb, unsigned int final)
> +{
> + unsigned int i;
> + struct sk_buff *skb1 = NULL;
> +
> + for (i = 0; i < count; i++) {
> + if (likely(skb1 == NULL))
> + skb1 = (i == final) ? skb : skb_clone(skb, GFP_ATOMIC);
> +
> + if (skb1 && udp_queue_rcv_skb(stack[i], skb1) <= 0)
> + skb1 = NULL;
> + }
> + if (skb1)
> + consume_skb(skb1);
> +}
consume_skb() assumes the skb was successfuly transmitted.
free_skb() does the same thing, but assumes that the frame is being dropped
after a failure and notes that.
In your code, if (count == 0) you:
* fail to remove the original skb (memory leak),
* simply consume the last dropped skb, without noting the droping failure.
I fixed these in the attached (untested) patch.
One last issue: you silently ignore dropped failures (skb1 is reused in case
of a failure).
If this tracing must record all failures, I'd add an
trace_kfree_skb(skb1, __builtin_return_address(0));
if udp_queue_rcv_skb() fails.
Other than this, nicely done!
--
Lucian
View attachment "udp-optimise-multicast-reception.patch" of type "text/plain" (2360 bytes)
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