From: David Miller <davem@davemloft.net>
To: dwmw2@infradead.org
Cc: eric.dumazet@gmail.com, netdev@vger.kernel.org,
simon@fire.lp0.eu, guy@traverse.com.au,
linux-atm-general@lists.sourceforge.net
Subject: Re: [PATCH v2] solos-pci: Increase headroom on received packets
Date: Thu, 17 Sep 2015 21:29:21 -0700 (PDT) [thread overview]
Message-ID: <20150917.212921.1620012798738986807.davem@davemloft.net> (raw)
In-Reply-To: <1442403300.131189.73.camel@infradead.org>
From: David Woodhouse <dwmw2@infradead.org>
Date: Wed, 16 Sep 2015 12:35:00 +0100
> A comment in include/linux/skbuff.h says that:
>
> * Various parts of the networking layer expect at least 32 bytes of
> * headroom, you should not reduce this.
>
> This was demonstrated by a panic when handling fragmented IPv6 packets:
> http://marc.info/?l=linux-netdev&m=144236093519172&w=2
>
> It's not entirely clear if that comment is still valid ― and if it is,
> perhaps netif_rx() ought to be enforcing it with a warning.
>
> But either way, it is rather stupid from a performance point of view
> for us to be receiving packets into a buffer which doesn't have enough
> room to prepend an Ethernet header ― it means that *every* incoming
> packet is going to be need to be reallocated. So let's fix that.
>
> Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
Applied, thanks David.
prev parent reply other threads:[~2015-09-18 4:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-16 10:25 [PATCH] solos-pci: Increase headroom on received packets David Woodhouse
2015-09-16 10:53 ` Eric Dumazet
2015-09-16 11:32 ` David Woodhouse
2015-09-16 11:35 ` [PATCH v2] " David Woodhouse
2015-09-16 13:26 ` Eric Dumazet
2015-09-18 4:29 ` David Miller [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20150917.212921.1620012798738986807.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=dwmw2@infradead.org \
--cc=eric.dumazet@gmail.com \
--cc=guy@traverse.com.au \
--cc=linux-atm-general@lists.sourceforge.net \
--cc=netdev@vger.kernel.org \
--cc=simon@fire.lp0.eu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).