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From: Mark McLoughlin <markmc@redhat.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: netdev@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 3/4] virtio_net: don't free buffers in xmit ring
Date: Tue, 02 Jun 2009 12:41:42 +0100	[thread overview]
Message-ID: <1243942902.9146.216.camel@blaa> (raw)
In-Reply-To: <1243930422.9146.60.camel@blaa>

On Tue, 2009-06-02 at 09:13 +0100, Mark McLoughlin wrote:
> On Fri, 2009-05-29 at 23:46 +0930, Rusty Russell wrote:
> > The virtio_net driver is complicated by the two methods of freeing old
> > xmit buffers (in addition to freeing old ones at the start of the xmit
> > path).
> > 
> > The original code used a 1/10 second timer attached to xmit_free(),
> > reset on every xmit.  Before we orphaned skbs on xmit, the
> > transmitting userspace could block with a full socket until the timer
> > fired, the skb destructor was called, and they were re-woken.
> 
> The timer was actually added to solve a hang when trying to unload
> nf_conntrack AFAIR - nf_conntrack was blocking on the skb being freed
> and we never actually freed it.
> 
> I think skb_orphan() is enough to prevent this, is it?

Oops, I meant:

  I don't think skb_orphan() is enough to prevent this, is it?

Cheers,
Mark.


  reply	other threads:[~2009-06-02 11:41 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-29 14:16 [PATCH 3/4] virtio_net: don't free buffers in xmit ring Rusty Russell
2009-06-02  8:13 ` Mark McLoughlin
2009-06-02 11:41   ` Mark McLoughlin [this message]
2009-06-02 14:07     ` Rusty Russell
2009-06-02 13:43   ` Rusty Russell

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