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From: Stephen Hemminger <shemminger@vyatta.com>
To: Patrick McHardy <kaber@trash.net>, David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org
Subject: [PATCH] TBF: stop qdisc infanticide
Date: Thu, 13 May 2010 09:17:17 -0700	[thread overview]
Message-ID: <20100513091717.78bd7f1f@nehalam> (raw)

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;
+	} else if (qopt->limit > 0) {
 		child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit);
 		if (IS_ERR(child)) {
 			err = PTR_ERR(child);

             reply	other threads:[~2010-05-13 16:17 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-13 16:17 Stephen Hemminger [this message]
2010-05-13 16:22 ` [PATCH] TBF: stop qdisc infanticide Patrick McHardy
2010-05-13 16:27   ` Stephen Hemminger
2010-05-13 16:30     ` Patrick McHardy
2010-05-15  0:38       ` [PATCH] tbf: stop wanton destruction of children (v2) Stephen Hemminger

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