This is a note to let you know that I've just added the patch titled sch_hfsc: always keep backlog updated to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: sch_hfsc-always-keep-backlog-updated.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 357cc9b4a8a7a0cd0e662537b76e6fa4670b6798 Mon Sep 17 00:00:00 2001 From: WANG Cong <xiyou.wangcong@xxxxxxxxx> Date: Wed, 1 Jun 2016 16:15:15 -0700 Subject: sch_hfsc: always keep backlog updated From: WANG Cong <xiyou.wangcong@xxxxxxxxx> commit 357cc9b4a8a7a0cd0e662537b76e6fa4670b6798 upstream. hfsc updates backlog lazily, that is only when we dump the stats. This is problematic after we begin to update backlog in qdisc_tree_reduce_backlog(). Reported-by: Stas Nichiporovich <stasn77@xxxxxxxxx> Tested-by: Stas Nichiporovich <stasn77@xxxxxxxxx> Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too") Cc: Jamal Hadi Salim <jhs@xxxxxxxxxxxx> Signed-off-by: Cong Wang <xiyou.wangcong@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sched/sch_hfsc.c | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) --- a/net/sched/sch_hfsc.c +++ b/net/sched/sch_hfsc.c @@ -1529,6 +1529,7 @@ hfsc_reset_qdisc(struct Qdisc *sch) q->eligible = RB_ROOT; INIT_LIST_HEAD(&q->droplist); qdisc_watchdog_cancel(&q->watchdog); + sch->qstats.backlog = 0; sch->q.qlen = 0; } @@ -1559,14 +1560,6 @@ hfsc_dump_qdisc(struct Qdisc *sch, struc struct hfsc_sched *q = qdisc_priv(sch); unsigned char *b = skb_tail_pointer(skb); struct tc_hfsc_qopt qopt; - struct hfsc_class *cl; - unsigned int i; - - sch->qstats.backlog = 0; - for (i = 0; i < q->clhash.hashsize; i++) { - hlist_for_each_entry(cl, &q->clhash.hash[i], cl_common.hnode) - sch->qstats.backlog += cl->qdisc->qstats.backlog; - } qopt.defcls = q->defcls; if (nla_put(skb, TCA_OPTIONS, sizeof(qopt), &qopt)) @@ -1604,6 +1597,7 @@ hfsc_enqueue(struct sk_buff *skb, struct if (cl->qdisc->q.qlen == 1) set_active(cl, qdisc_pkt_len(skb)); + qdisc_qstats_backlog_inc(sch, skb); sch->q.qlen++; return NET_XMIT_SUCCESS; @@ -1672,6 +1666,7 @@ hfsc_dequeue(struct Qdisc *sch) qdisc_unthrottled(sch); qdisc_bstats_update(sch, skb); + qdisc_qstats_backlog_dec(sch, skb); sch->q.qlen--; return skb; @@ -1695,6 +1690,7 @@ hfsc_drop(struct Qdisc *sch) } cl->qstats.drops++; qdisc_qstats_drop(sch); + sch->qstats.backlog -= len; sch->q.qlen--; return len; } Patches currently in stable-queue which might be from xiyou.wangcong@xxxxxxxxx are queue-4.4/sch_sfb-keep-backlog-updated-with-qlen.patch queue-4.4/sch_hfsc-always-keep-backlog-updated.patch queue-4.4/sch_drr-update-backlog-as-well.patch queue-4.4/sch_tbf-update-backlog-as-well.patch queue-4.4/sch_prio-update-backlog-as-well.patch queue-4.4/net_sched-keep-backlog-updated-with-qlen.patch queue-4.4/sch_qfq-keep-backlog-updated-with-qlen.patch