From: Shirley Ma <mashirle@us.ibm.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: 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
Subject: Re: [PATCH V3 2/8] Add a new zerocopy device flag
Date: Tue, 03 May 2011 10:42:50 -0700 [thread overview]
Message-ID: <1304444570.20660.32.camel@localhost.localdomain> (raw)
In-Reply-To: <20110502195302.GA25619@redhat.com>
On Mon, 2011-05-02 at 22:53 +0300, Michael S. Tsirkin wrote:
> On Mon, May 02, 2011 at 11:47:08AM -0700, Shirley Ma wrote:
> > On Mon, 2011-05-02 at 13:42 +0300, Michael S. Tsirkin wrote:
> > > This comment should specify what exactly is the promise the
> > > device makes by setting this flag. Specifically, the
> > > condition is that no skb fragments are used
> > > after the uinfo callback has been called.
> > >
> > > The way it's implemented, it probably means the device
> > > should not use any of skb_clone, expand head etc.
> >
> > Agree. Or maybe force a copy when device uses skb_clone, expand
> > head ...?
> >
> > Thanks
> > Shirley
>
> Copy from userspace upfront without locking is probably cheaper?
Better to prevent this kind of skbs to be used in skb_clone, expand head
for now.
Thanks
Shirley
next prev parent reply other threads:[~2011-05-03 17:42 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-20 19:36 [PATCH V3 0/8] macvtap/vhost TX zero copy support Shirley Ma
2011-04-20 19:42 ` [PATCH V3 1/8] Add a new sock zerocopy flag Shirley Ma
2011-04-20 19:44 ` [PATCH V3 2/8] Add a new zerocopy device flag Shirley Ma
2011-04-20 19:48 ` Ben Hutchings
2011-04-20 20:05 ` Shirley Ma
2011-04-20 20:09 ` Shirley Ma
2011-04-20 20:24 ` Dimitris Michailidis
2011-04-20 20:28 ` Shirley Ma
2011-04-20 20:30 ` Shirley Ma
2011-05-02 10:42 ` Michael S. Tsirkin
2011-05-02 18:47 ` Shirley Ma
2011-05-02 19:53 ` Michael S. Tsirkin
2011-05-03 17:42 ` Shirley Ma [this message]
2011-05-03 20:11 ` Shirley Ma
2011-04-20 19:47 ` [PATCH V3 3/8] Add userspace buffers support in skb Shirley Ma
2011-05-02 10:53 ` Michael S. Tsirkin
2011-05-03 17:36 ` Shirley Ma
2011-04-20 20:07 ` [PATCH V3 4/8] vhost TX zero copy support Shirley Ma
2011-04-20 20:12 ` [PATCH V3 0/8] macvtap/vhost " Shirley Ma
2011-04-20 20:13 ` [PATCH V3 5/8] Enable cxgb3 to support zerocopy Shirley Ma
2011-04-20 20:52 ` Dimitris Michailidis
2011-04-20 20:58 ` Shirley Ma
2011-04-20 21:15 ` Shirley Ma
2011-04-20 20:15 ` [PATCH V3 7/8] Enable ixgbe " Shirley Ma
2011-04-20 20:17 ` [PATCH V3 8/8] Enable benet " Shirley Ma
2011-04-20 20:27 ` [PATCH V3 6/8] macvtap/vhost TX zero copy support Shirley Ma
2011-05-02 18:35 ` Shirley Ma
2011-04-21 14:29 ` [PATCH V3 0/8] " Jon Mason
2011-04-22 17:31 ` Shirley Ma
2011-04-22 17:52 ` Shirley Ma
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