From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?ISO-8859-2?Q?Micha=B3_Miros=B3aw?= <mirqus@gmail.com>
Subject: Re: [PATCH V5 2/6 net-next] netdevice.h: Add zero-copy flag in netdevice
Date: Wed, 18 May 2011 00:58:00 +0200
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Cc: "Michael S. Tsirkin" <mst@redhat.com>,
	Ben Hutchings <bhutchings@solarflare.com>,
	David Miller <davem@davemloft.net>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	Avi Kivity <avi@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
	netdev@vger.kernel.org, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org
To: Shirley Ma <mashirle@us.ibm.com>
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W dniu 18 maja 2011 00:28 u=BFytkownik Shirley Ma <mashirle@us.ibm.com>=
 napisa=B3:
> On Tue, 2011-05-17 at 23:48 +0200, Micha=B3 Miros=B3aw wrote:
>> 2011/5/17 Shirley Ma <mashirle@us.ibm.com>:
>> > Looks like to use a new flag requires more time/work. I am thinkin=
g
>> > whether we can just use HIGHDMA flag to enable zero-copy in macvta=
p
>> to
>> > avoid the new flag for now since mavctap uses real NICs as lower
>> device?
>>
>> Is there any other restriction besides requiring driver to not recyc=
le
>> the skb? Are there any drivers that recycle TX skbs?
> Not more other restrictions, skb clone is OK. pskb_expand_head() look=
s
> OK to me from code review.

> Currently there is no drivers recycle TX skbs.

So why do you require the target device to have some flags at all?

Do I understand correctly, that this zero-copy feature is about
packets received from VMs?

Best Regards,
Micha=B3 Miros=B3aw