Re: problems with e1000 and jumboframes

From: Krzysztof Oledzki
Date: Thu Aug 03 2006 - 11:07:01 EST

On Thu, 3 Aug 2006, Evgeniy Polyakov wrote:
Why? After your explanation that makes sense for me. The driver needs
one contiguous chunk for those 9k packet buffer and thus requests a
3-order page of 16k. Or do i still do not understand this?

Correct, except that it wants 32k.
e1000 logic is following:
align frame size to power-of-two,

then skb_alloc adds a little
(sizeof(struct skb_shared_info)) at the end, and this ends up
in 32k request just for 9k jumbo frame.

Strange, why this skb_shared_info cannon be added before first alignment? And what about smaller frames like 1500, does this driver behave similar (first align then add)?

Best regards,

Krzysztof Olędzki