netdev - Re: [PATCH 0/2] Disable forwarding of LRO skbs

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Message-Id: <E1JrVtK-0001pb-00@gondolin.me.apana.org.au>
Date:	Thu, 01 May 2008 18:19:54 +0800
From:	Herbert Xu <herbert@...dor.apana.org.au>
To:	davem@...emloft.net (David Miller)
Cc:	bhutchings@...arflare.com, kmansley@...arflare.com,
	shemminger@...tta.com, netdev@...r.kernel.org
Subject: Re: [PATCH 0/2] Disable forwarding of LRO skbs

David Miller <davem@...emloft.net> wrote:
> From: Ben Hutchings <bhutchings@...arflare.com>
> Date: Wed, 30 Apr 2008 22:48:46 +0100
> 
>> Large Receive Offload (LRO) destroys packet headers that should be
>> preserved when forwarding.  Currently it also triggers a BUG() or WARN()
>> in skb_gso_segment().  We should disable it wherever forwarding is
>> enabled, and discard LRO skbs with a warning if it is turned back on.
> 
> Thanks for reposting your work, I'll take a closer look at these
> two patches later today.

This patch completely breaks forwarding of GSO packets in a
virtualised environment where we explicitly want to forward
them as is to reduce per-packet overhead.  So if LRO is causing
problems then I suggest we find a better way around that that
does not penalise all forms of GSO.

Thanks,
-- 
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Email: Herbert Xu ~{PmV>HI~} <herbert@...dor.apana.org.au>
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