netdev - Re: [PATCH RFC 00/14] shrink skb cb to 44 bytes

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 02 Mar 2015 13:56:40 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Florian Westphal <fw@...len.de>
Cc:	netdev@...r.kernel.org, Johannes Berg <johannes@...solutions.net>,
	linux-wireless@...r.kernel.org
Subject: Re: [PATCH RFC 00/14] shrink skb cb to 44 bytes

On Mon, 2015-03-02 at 21:42 +0100, Florian Westphal wrote:

> Thats right.  Do you think its worth to already move cb[] near the end
> of skb and alter build_skb to not clear it anymore?
> 
> Which of the ideas, in your opinion, is worth pursuing first (if any)?

moving cb[] near the end will void my patches to use one cache line per
skb in TCP receive queue ( or write queue)

971f10eca186ca tcp: better TCP_SKB_CB layout to reduce cache line misses


I have worked a bit (3 months ago) about doing the skb->cb[] selective
clearing, but a lot of alloc_skb() users _assume_ it is already
cleared. 

That seemed a lot of work to me, because of the many alloc_skb()
variants we have. But definitely worth trying to complete.



--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html