On Mon, Jan 26, 2009 at 10:10:56PM -0800, David Miller wrote:

quoted text
> From: Evgeniy Polyakov

> Date: Tue, 27 Jan 2009 00:21:30 +0300

>

> > Hi Jarek.

> >

> > On Mon, Jan 26, 2009 at 08:20:36AM +0000, Jarek Poplawski (jarkao2@gmail.com) wrote:

> > > > 1. Network (tree) allocator

> > > > http://www.ioremap.net/projects/nta

> > >

> > > I looked at this a bit, but alas I didn't find much for this Herbert's

> > > idea of payload in fragments/pages. Maybe some kind of API RFC is

> > > needed before this resurrection?

> >

> > Basic idea is to steal some (probably a lot) pages from the slab

> > allocator and put network buffers there without strict need for

> > power-of-two alignment and possible wraps when we add skb_shared_info at

> > the end, so that old e1000 driver required order-4 allocations for the

> > jumbo frames. We can do that in alloc_skb() and friends and put returned

> > buffers into skb's fraglist and updated reference counters for those

> > pages; and with additional copy of the network headers into skb->head.

I think the main problem is to respect put_page() more, and maybe you

mean to add this to your allocator too, but using slab pages for this

looks a bit complex to me, but I can miss something.
> We are going back and forth saying the same thing, I think :-)

quoted text
> (BTW, I think NTA is cool and we might do something like that

> eventually)

>

> The basic thing we have to do is make the drivers receive into

> pages, and then slide the network headers (only) into the linear

> SKB data area.

As a matter of fact, I wonder if these headers should be always

separated. Their "chunk" could be refcounted as well, I guess.
Jarek P.

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