Subject: Re: [RFC] avoid unnecessary alignement overhead in skb->data allocation.

From: Evgeniy Polyakov <[email-masked]>
Date: Tue, 8 Aug 2006 09:55:24 +0400

On Tue, Aug 08, 2006 at 03:41:15PM +1000, Herbert Xu ([email-masked]) wrote:
> On Tue, Aug 08, 2006 at 09:24:08AM +0400, Evgeniy Polyakov wrote:
> > 
> > So there is no place at the end of skb for additional pointer.
> > And new question arises - until what Jesse suggested is implemented in
> > some way, do we need to store a pointer to shared info inside skb and
> > allocate it from cache in case it does no fit into aligned buffer (in
> > case of e1000 it happens all the time exept 1500 MTU)?
> > David, Herbert?
> 
> I'm not sure whether this is really worth it.  After all, the only
> order of allocation that's really likely to succeed is 0.  So going
> from order 3 to order 2 probably doesn't make that big a difference.

16k is quite big overhead and it is much more possible to succeed than
32k, but in general, yes, only order 0 can succeed.
So right now we can mark e1000 and other cards, which do not support
frag_list generation as not supporting jumbo frames?

> Cheers,
> -- 
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> Email: Herbert Xu ~{PmV>HI~} <[email-masked]>
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-- 
	Evgeniy Polyakov