linux-kernel - Re: skbuff truesize incorrect.

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]

Message-ID: <1400790603.5367.167.camel@edumazet-glaptop2.roam.corp.google.com>
Date:	Thu, 22 May 2014 13:30:03 -0700
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Jim Baxter <jim_baxter@...tor.com>
Cc:	David Miller <davem@...emloft.net>, linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
	kamal@...onical.com, bhutchings@...arflare.com,
	edumazet@...gle.com, mszeredi@...e.cz, fw@...len.de
Subject: Re: skbuff truesize incorrect.

On Thu, 2014-05-22 at 21:21 +0100, Jim Baxter wrote:


> OK, so it is the value of the memory that has been allocated for the SKB.
> If there are multiple clones for an skb all pointing at the same data,
> will that distort the memory used when they all have the same truesize?

Its always better to over estimate memory uses, than under estimating.

Its all about guarding against OOM.

Keep in mind some parts of networking stack do not like clones.

TCP coalescing works beautifully with non cloned skbs.

Instead of cloning skb or doing copies, you could play with having frame
on a page fragment. Only headers might need to be pulled from the frame
to linear part of skb.





--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/