From: Patrick McHardy <kaber@trash•net>
To: Stephen Hemminger <shemminger@vyatta•com>
Cc: David Miller <davem@davemloft•net>, netdev@vger•kernel.org
Subject: Re: [PATCH] TBF: stop qdisc infanticide
Date: Thu, 13 May 2010 18:30:46 +0200 [thread overview]
Message-ID: <4BEC2936.2060800@trash.net> (raw)
In-Reply-To: <20100513092728.766ee059@nehalam>
Stephen Hemminger wrote:
> On Thu, 13 May 2010 18:22:56 +0200
> Patrick McHardy <kaber@trash•net> wrote:
>
>> Stephen Hemminger wrote:
>>> Several netem users have complained that when using TBF for rate control
>>> that any change to TBF parameters destroys the child qdisc. A typical
>>> use is to have a test that sets up netem + TBF then changes bandwidth
>>> setting. But every time the parameters of TBF are changed it destroys
>>> the child qdisc, requiring reconfiguration. Other qdisc's like HTB
>>> don't do this.
>>>
>>> Signed-off-by: Stephen Hemminger <shemminger@vyatta•com>
>>>
>>>
>>> --- a/net/sched/sch_tbf.c 2010-05-12 20:41:06.257006386 -0700
>>> +++ b/net/sched/sch_tbf.c 2010-05-12 20:52:35.671216316 -0700
>>> @@ -273,7 +273,11 @@ static int tbf_change(struct Qdisc* sch,
>>> if (max_size < 0)
>>> goto done;
>>>
>>> - if (qopt->limit > 0) {
>>> + if (q->qdisc) {
>>> + err = fifo_set_limit(q->qdisc, qopt->limit);
>>> + if (err)
>>> + goto done;
>> q->qdisc is never NULL since a noop_qdisc is assigned by default. Also
>> this should check that the child is in fact one of the *fifos.
>
> But the child will be netem and fifo_set_limit ignores non-fifo.
OK, but it does need to make sure the child is not a noop_qdisc,
otherwise it won't create the default bfifo.
next prev parent reply other threads:[~2010-05-13 16:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-13 16:17 [PATCH] TBF: stop qdisc infanticide Stephen Hemminger
2010-05-13 16:22 ` Patrick McHardy
2010-05-13 16:27 ` Stephen Hemminger
2010-05-13 16:30 ` Patrick McHardy [this message]
2010-05-15 0:38 ` [PATCH] tbf: stop wanton destruction of children (v2) Stephen Hemminger
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