linear sk_buff

linear sk_buff

[Mark Ryden]

Hello,
 I would appreciate if someone in this mailing list  can say in a
sentence or two what is a linear
sk_buff and what is a non linear sk_buff; does it has to do with fragmentation?
(I am sure that many know the answer, but I am confused and googling
made me overconfused)

Regards, and sorry for the noise,

Mark

Re: linear sk_buff

[Phil Sutter]

Hi,

On Wed, May 05, 2010 at 10:12:06PM +0300, Mark Ryden wrote:
>  I would appreciate if someone in this mailing list  can say in a
> sentence or two what is a linear
> sk_buff and what is a non linear sk_buff; does it has to do with fragmentation?
> (I am sure that many know the answer, but I am confused and googling
> made me overconfused)

As far as I can tell, linear and non-linear sk_buffs differ in how the
data they contain is kept internally. Linear sk_buffs are trivial, it's
data resides in one, continuous block. In non-linear sk_buffs, data is
spread across multiple junks, organised in a data structure comparable
to e.g. scatterlists.

For further information, I'd highly recommend David Miller's "how SKBs
work": http://vger.kernel.org/~davem/skb.html .

Greetings, Phil

Re: linear sk_buff

[Rémi Denis-Courmont]

Le mercredi 5 mai 2010 22:12:06 Mark Ryden, vous avez écrit :
> Hello,
>  I would appreciate if someone in this mailing list  can say in a
> sentence or two what is a linear
> sk_buff and what is a non linear sk_buff; does it has to do with
> fragmentation? (I am sure that many know the answer, but I am confused and
> googling made me overconfused)

A linear sk_buff is one that has no memory pages and no fragments sk_buff.

Such a buffer is made of a contiguous portion of the (kernel) memory.


-- 
Rémi Denis-Courmont
http://www.remlab.net/
http://fi.linkedin.com/in/remidenis