From: David Miller <davem@davemloft.net>
To: herbert@gondor.apana.org.au
Cc: netdev@vger.kernel.org
Subject: Re: TX pre-headers...
Date: Mon, 09 Feb 2009 02:14:03 -0800 (PST) [thread overview]
Message-ID: <20090209.021403.56830306.davem@davemloft.net> (raw)
In-Reply-To: <20090209100713.GA8299@gondor.apana.org.au>
From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Mon, 9 Feb 2009 21:07:13 +1100
> David Miller <davem@davemloft.net> wrote:
> >
> > I think the way to solve this is to have each device indicate how
> > much TX slack space it neads for it's preheaders. On device
> > registration we have some global "netdev_max_tx_hdr_space" that
> > records the maximum value seen.
>
> We can already solve it right now with dev->needed_headroom.
>
> Of course it's not optimal because it involves a copy so we
> might still need your solution.
Indeed, I noticed needed_headroom when I set out to start coding
things up. :)
There are all sorts of cases that won't work well, as you implicitly
suggest. For example, forwarding to a path that encapsulates to a GRE
or other type of tunnel.
For IPSEC we're predominantly COW'ing the data anyways, so...
next prev parent reply other threads:[~2009-02-09 10:14 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-02-06 9:41 TX pre-headers David Miller
2009-02-06 10:46 ` Steve.Glendinning
2009-02-06 11:11 ` David Miller
2009-02-06 18:53 ` Inaky Perez-Gonzalez
2009-02-06 12:02 ` Frank Blaschka
2009-02-07 8:10 ` David Miller
2009-02-09 3:34 ` David Miller
2009-02-09 10:07 ` Herbert Xu
2009-02-09 10:14 ` David Miller [this message]
2009-02-09 10:19 ` Herbert Xu
2009-02-09 15:39 ` Krzysztof Halasa
2009-02-10 8:15 ` David Miller
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