netdev - Re: net_sched 07/07: add classful multiqueue dummy scheduler

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Message-ID: <4AA8E2FB.3040809@trash.net>
Date:	Thu, 10 Sep 2009 13:28:59 +0200
From:	Patrick McHardy <kaber@...sh.net>
To:	Jarek Poplawski <jarkao2@...il.com>
CC:	Eric Dumazet <eric.dumazet@...il.com>, netdev@...r.kernel.org
Subject: Re: net_sched 07/07: add classful multiqueue dummy scheduler

Jarek Poplawski wrote:
> On Wed, Sep 09, 2009 at 06:02:59PM +0200, Patrick McHardy wrote:
>>>>>>> +	for (ntx = 0; ntx < dev->num_tx_queues; ntx++) {
>>>>>>> +		qdisc = netdev_get_tx_queue(dev, ntx)->qdisc_sleeping;
>>>>>>> +		spin_lock_bh(qdisc_lock(qdisc));
>>>>>>> +		sch->q.qlen		+= qdisc->q.qlen;
>>>>>>> +		sch->bstats.bytes	+= qdisc->bstats.bytes;
>>>>>>> +		sch->bstats.packets	+= qdisc->bstats.packets;
>>>>>>> +		sch->qstats.qlen	+= qdisc->qstats.qlen;
>>>>>> Like in Christoph's case, we should probably use q.qlen instead.
>>>>> Its done a few lines above. This simply sums up all members of qstats.
>>>> AFAICS these members are updated only in tc_fill_qdisc, starting from
>>>> the root, so they might be not up-to-date at the moment, unless I miss
>>>> something.
>>> Yes, we might need an q->ops->update_stats(struct Qdisc *sch) method, and
>>> to recursively call it from mq_update_stats()
>> Unless I'm missing something, that shouldn't be necessary since
>> sch->q.qlen contains the correct sum of all child qdiscs and
>> this is used by tc_fill_qdisc to update qstats.qlen.
> 
> You're perfectly right! (And the code is perfectly misleading.;-)

I'll remove the misleading (and unnecessary) line of code, thanks Jarek.
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