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From: Thomas Graf <tgraf@suug.ch>
To: "Waskiewicz Jr, Peter P" <peter.p.waskiewicz.jr@intel.com>
Cc: "Kok, Auke-jan H" <auke-jan.h.kok@intel.com>,
	David Miller <davem@davemloft.net>,
	"Garzik, Jeff" <jgarzik@pobox.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	"Brandeburg, Jesse" <jesse.brandeburg@intel.com>,
	"Kok, Auke" <auke@foo-projects.org>,
	"Ronciak, John" <john.ronciak@intel.com>
Subject: Re: [PATCH 1/2] NET: Multiple queue network device support
Date: Sat, 10 Mar 2007 03:34:32 +0100	[thread overview]
Message-ID: <20070310023432.GJ521@postel.suug.ch> (raw)
In-Reply-To: <D5C1322C3E673F459512FB59E0DDC329026E9F85@orsmsx414.amr.corp.intel.com>

* Waskiewicz Jr, Peter P <peter.p.waskiewicz.jr@intel.com> 2007-03-09 15:27
> That's the entire point of this extra locking.  enqueue() is going to
> put an skb into a band somewhere that maps to some queue, and there is
> no way to guarantee the skb I retrieve from dequeue() is headed for the
> same queue.  Therefore, I need to unlock the queue after I finish
> enqueuing, since having that lock makes little sense to dequeue().
> dequeue() will then grab *a* lock on a queue; it may be the same one we
> had during enqueue(), but it may not be.  And the placement of the
> unlock of that queue is exactly where it happens in non-multiqueue,
> which is right before the hard_start_xmit().

The lock is already unlocked after dequeue, from your prio_dequeue():

       if (netif_is_multiqueue(sch->dev)) {
               queue = q->band2queue[prio];
               if (spin_trylock(&sch->dev->egress_subqueue[queue].queue_lock)) {
                       qdisc = q->queues[prio];
                       skb = qdisc->dequeue(qdisc);
                       if (skb) {
                               sch->q.qlen--;
                               skb->priority = prio;
                               spin_unlock(&sch->dev->egress_subqueue[queue].queue_lock);
                               return skb;
                       }
                       spin_unlock(&sch->dev->egress_subqueue[queue].queue_lock);
       }

  reply	other threads:[~2007-03-10  2:34 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-09  0:09 [PATCH 0/2 REVIEW] Multiple transmit/receive queue kernel Kok, Auke
2007-02-09  0:09 ` [PATCH 1/2] NET: Multiple queue network device support Kok, Auke
2007-02-27  1:03   ` David Miller
2007-02-27 19:38     ` Waskiewicz Jr, Peter P
2007-03-07 22:18     ` Waskiewicz Jr, Peter P
2007-03-07 22:42       ` David Miller
2007-03-09  7:26         ` Jarek Poplawski
2007-03-09 13:40   ` Thomas Graf
2007-03-09 19:25     ` Waskiewicz Jr, Peter P
2007-03-09 23:01       ` Thomas Graf
2007-03-09 23:27         ` Waskiewicz Jr, Peter P
2007-03-10  2:34           ` Thomas Graf [this message]
2007-03-10 20:37             ` Waskiewicz Jr, Peter P
2007-03-12  8:58     ` Jarek Poplawski
2007-03-12 20:21       ` Waskiewicz Jr, Peter P
2007-02-09  0:09 ` [PATCH 2/2] e1000: Implement the new kernel API for multiqueue TX support Kok, Auke
2007-03-09 13:11   ` Thomas Graf
2007-02-23  9:00 [PATCH 1/2] NET: Multiple queue network device support Sreenivasa Honnur
2007-02-23 19:05 ` Waskiewicz Jr, Peter P
2007-02-23 19:19 ` Stephen Hemminger
2007-02-23 19:23   ` Kok, Auke
2007-02-23  9:02 Sreenivasa Honnur

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