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Re: [Xen-devel] [patch 6/6] netif_release_rx_bufs

To: Gerd Hoffmann <kraxel@xxxxxxx>
Subject: Re: [Xen-devel] [patch 6/6] netif_release_rx_bufs
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Fri, 18 Aug 2006 13:25:35 +0100
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On 18/8/06 12:34 pm, "Gerd Hoffmann" <kraxel@xxxxxxx> wrote:

> Keir Fraser wrote:
>> You've given up the original mfns at this point, to ensure you have enough
>> reservation headroom for the transfer. You'll be wanting to give the 'empty
>> mfn' to the balloon driver, which can simply stick the page on its
>> ballooned-out list. You might need to add a new API function to balloon
>> driver to do this.
> Passing the page to the balloon driver works ok, but then I have trouble
> releasing the skb because shinfo(skb)->frags[0].page isn't valid any
> more.  Guess I better aquire a page from xen in netfront instead of
> letting the ballon driver do that ...

Best bet is to free the page to the balloon driver, and then set nr_frags to
zero. This is perfectly valid -- it was netfront that set it to non-zero in
the first place.

 -- Keir

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