Re: [PLEASE-TESTME] Zerocopy networking patch, 2.4.0-1

[Gerd Knorr]

> > Please tell me what you think the right interface is that provides a hook
> > on io completion and is asynchronous.
> 
> Suggested fix to kiovec's: get rid of them. Immediately. Replace them with
> kiobuf's that can handle scatter-gather pages. kiobuf's have 90% of that
> support already.
> 
> Never EVER have a "struct page **" interface. It is never the valid thing
> to do.

Hmm, /me is quite happy with it.  It's fine for *big* chunks of memory like
video frames:  I just need a large number of pages, length and offset.  If
someone wants to have a look: a rewritten bttv version which uses kiobufs
is available at http://www.strusel007.de/linux/bttv/bttv-0.8.8.tar.gz

It does _not_ use kiovecs throuth (to be exact: kiovecs with just one single
kiobuf in there).

> You should have
> 
> 	struct fragment {
> 		struct page *page;
> 		__u16 offset, length;
> 	}

What happens with big memory blocks?  Do all pages but the first and last
get offset=0 and length=PAGE_SIZE then?

  Gerd

-- 
Get back there in front of the computer NOW. Christmas can wait.
	-- Linus "the Grinch" Torvalds,  24 Dec 2000 on linux-kernel