From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH] xen/netfront: improve truesize tracking
Date: Mon, 07 Jan 2013 07:26:39 -0800
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Cc: Sander Eikelenboom <linux@eikelenboom.it>,
	Rick Jones <rick.jones2@hp.com>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
	annie li <annie.li@oracle.com>,
	"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
To: Ian Campbell <Ian.Campbell@citrix.com>
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On Mon, 2013-01-07 at 14:22 +0000, Ian Campbell wrote:
> On Mon, 2013-01-07 at 14:11 +0000, Sander Eikelenboom wrote:
> one is buggy.
> > 
> > Will see if i can run against that as well, although i thought Eric
> > said to prefer the "skb->truesize += PAGE_SIZE *
> > skb_shinfo(skb)->nr_frags;"
> 
> Right, I meant to compare "PAGE_SIZE * skb_shinfo(skb)->nr_frags" vs
> "skb->data_len - NETFRONT_SKB_CB(skb)->pull_to". TBH I trust Eric so I'm
> inclined to just go with what he suggests.

This is the more precise estimation, and it appears to not bring obvious
performance regression, so I definitely would favor this one ;)