netdev - Re: [PATCH] act_mirred: don't clone skb when skb isn't shared

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Message-Id: <1275742435.3490.31.camel@bigi>
Date:	Sat, 05 Jun 2010 08:53:55 -0400
From:	jamal <hadi@...erus.ca>
To:	Changli Gao <xiaosuo@...il.com>
Cc:	"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH] act_mirred: don't clone skb when skb isn't shared

On Fri, 2010-06-04 at 21:43 +0800, Changli Gao wrote:
> don't clone skb when skb isn't shared
> 
> When the tcf_action is TC_ACT_STOLEN, and the skb isn't shared, we don't need
> to clone a new skb. As the skb will be freed after this function returns, we
> can use it freely once we get a reference to it.

It looks like a good optimization - but i am not a big fan of one-offs
[because usability goes down and I am forced to explain it longer in the
rules (refer to: Documentation/networking/tc-actions-env-rules.txt)]

How about you update skb_act_clone to take take the action code as well
and do the check the if stolen/queued it does a skb_get otherwise it
calls skb_clone?

cheers,
jamal

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