From: Jeremy Fitzhardinge <jeremy@goop•org>
To: Ian Campbell <Ian.Campbell@eu•citrix.com>
Cc: "netdev@vger•kernel.org" <netdev@vger•kernel.org>,
Rusty Russell <rusty@rustcorp•com.au>,
xen-devel <xen-devel@lists•xensource.com>
Subject: Re: SKB paged fragment lifecycle on receive
Date: Fri, 24 Jun 2011 15:48:21 -0700 [thread overview]
Message-ID: <4E051435.8080302@goop.org> (raw)
In-Reply-To: <1308955477.5807.8.camel@dagon.hellion.org.uk>
On 06/24/2011 03:44 PM, Ian Campbell wrote:
> One problem with this is that some functions (__pskb_pull_tail) drop the
> ref count and then remove the page from the skb's fraglist. So by the
> time the destructor is called you have lost the page and cannot do the
> refcount checking.
>
> I suppose we could keep a queue of _all_ pages we ever put in an SKB
> which we poll.
Right, that seems like the only way to make sure we don't lose anything.
> We could still check for pages with count==1 in the
> destructor. Apart from the other issues with the destructor not being
> copied over clone etc which would cause us to fall-back to polling the
> queue more often than not I reckon.
Yeah, sounds like it.
>> That said, I think an event-based rather than polling based mechanism
>> would be much more preferable.
> Absolutely.
>From what Eric and David were saying, it seems we don't really have any
other workable options.
J
next prev parent reply other threads:[~2011-06-24 22:48 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-24 15:43 SKB paged fragment lifecycle on receive Ian Campbell
2011-06-24 17:29 ` Jeremy Fitzhardinge
2011-06-24 17:56 ` Eric Dumazet
2011-06-24 18:21 ` Jeremy Fitzhardinge
2011-06-24 19:46 ` David Miller
2011-06-24 20:11 ` Jeremy Fitzhardinge
2011-06-24 20:27 ` David Miller
2011-06-25 11:58 ` Ian Campbell
2011-06-27 20:51 ` Jeremy Fitzhardinge
2011-06-28 10:25 ` Ian Campbell
2011-06-27 14:42 ` Ian Campbell
2011-06-27 22:49 ` David Miller
2011-06-28 10:24 ` Ian Campbell
2011-06-24 22:44 ` Ian Campbell
2011-06-24 22:48 ` Jeremy Fitzhardinge [this message]
2011-06-26 10:25 ` Michael S. Tsirkin
2011-06-27 9:41 ` Ian Campbell
2011-06-27 10:21 ` Michael S. Tsirkin
2011-06-27 10:54 ` Ian Campbell
2011-06-27 11:19 ` Michael S. Tsirkin
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