Subject: Re: problems with e1000 and jumboframes

From: Evgeniy Polyakov <[email-masked]>
Date: Thu, 3 Aug 2006 19:41:26 +0400

On Thu, Aug 03, 2006 at 07:16:31PM +0400, Evgeniy Polyakov ([email-masked]) wrote:
> > >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)?
> 
> It can be.
> Could attached  (completely untested) patch help?

Actually this patch will not help, this new one could.

diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index da62db8..1514628 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -3978,9 +3978,11 @@ e1000_alloc_rx_buffers(struct e1000_adap
 	buffer_info = &rx_ring->buffer_info[i];
 
 	while (cleaned_count--) {
-		if (!(skb = buffer_info->skb))
+		if (!(skb = buffer_info->skb)) {
+			if (SKB_DATA_ALIGN(adapter->hw.max_frame_size) + sizeof(struct skb_shared_info) <= bufsz)
+				bufsz -= sizeof(struct skb_shared_info);
 			skb = dev_alloc_skb(bufsz);
-		else {
+		} else {
 			skb_trim(skb, 0);
 			goto map_skb;
 		}

-- 
	Evgeniy Polyakov