sch_htb: update backlog as well

[ Upstream commit 431e3a8e36a05a37126f34b41aa3a5a6456af04e ]

We saw qlen!=0 but backlog==0 on our production machine:

qdisc htb 1: dev eth0 root refcnt 2 r2q 10 default 1 direct_packets_stat 0 ver 3.17
 Sent 172680457356 bytes 222469449 pkt (dropped 0, overlimits 123575834 requeues 0)
 backlog 0b 72p requeues 0

The problem is we only count qlen for HTB qdisc but not backlog.
We need to update backlog too when we update qlen, so that we
can at least know the average packet length.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 6b118b1587cabfb786b4428750e6afd02fa09250..ccff00640713415d8d09a446482e3682f0514904 100644 (file)
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -600,6 +600,7 @@ static int htb_enqueue(struct sk_buff *skb, struct Qdisc *sch)
                htb_activate(q, cl);
        }
 
+       qdisc_qstats_backlog_inc(sch, skb);
        sch->q.qlen++;
        return NET_XMIT_SUCCESS;
 }
@@ -889,6 +890,7 @@ static struct sk_buff *htb_dequeue(struct Qdisc *sch)
 ok:
                qdisc_bstats_update(sch, skb);
                qdisc_unthrottled(sch);
+               qdisc_qstats_backlog_dec(sch, skb);
                sch->q.qlen--;
                return skb;
        }
@@ -955,6 +957,7 @@ static unsigned int htb_drop(struct Qdisc *sch)
                        unsigned int len;
                        if (cl->un.leaf.q->ops->drop &&
                            (len = cl->un.leaf.q->ops->drop(cl->un.leaf.q))) {
+                               sch->qstats.backlog -= len;
                                sch->q.qlen--;
                                if (!cl->un.leaf.q->q.qlen)
                                        htb_deactivate(q, cl);
@@ -984,12 +987,12 @@ static void htb_reset(struct Qdisc *sch)
                        }
                        cl->prio_activity = 0;
                        cl->cmode = HTB_CAN_SEND;
-
                }
        }
        qdisc_watchdog_cancel(&q->watchdog);
        __skb_queue_purge(&q->direct_queue);
        sch->q.qlen = 0;
+       sch->qstats.backlog = 0;
        memset(q->hlevel, 0, sizeof(q->hlevel));
        memset(q->row_mask, 0, sizeof(q->row_mask));
        for (i = 0; i < TC_HTB_NUMPRIO; i++)