diff options
Diffstat (limited to 'nixos/modules/kernel-patches/0064-net_sched-codel-do-not-defer-queue-length-update.patch')
| -rw-r--r-- | nixos/modules/kernel-patches/0064-net_sched-codel-do-not-defer-queue-length-update.patch | 97 |
1 files changed, 97 insertions, 0 deletions
diff --git a/nixos/modules/kernel-patches/0064-net_sched-codel-do-not-defer-queue-length-update.patch b/nixos/modules/kernel-patches/0064-net_sched-codel-do-not-defer-queue-length-update.patch new file mode 100644 index 0000000..8c57508 --- /dev/null +++ b/nixos/modules/kernel-patches/0064-net_sched-codel-do-not-defer-queue-length-update.patch @@ -0,0 +1,97 @@ +From 9eee7822b071e5a658a176300336feeedd2b6205 Mon Sep 17 00:00:00 2001 +From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> +Date: Mon, 21 Aug 2017 11:14:14 +0300 +Subject: [PATCH 64/96] net_sched/codel: do not defer queue length update + +When codel wants to drop last packet in ->dequeue() it cannot call +qdisc_tree_reduce_backlog() right away - it will notify parent qdisc +about zero qlen and HTB/HFSC will deactivate class. The same class will +be deactivated second time by caller of ->dequeue(). Currently codel and +fq_codel defer update. This triggers warning in HFSC when it's qlen != 0 +but there is no active classes. + +This patch update parent queue length immediately: just temporary increase +qlen around qdisc_tree_reduce_backlog() to prevent first class deactivation +if we have skb to return. + +This might open another problem in HFSC - now operation peek could fail and +deactivate parent class. + +Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> +Link: https://bugzilla.kernel.org/show_bug.cgi?id=109581 +--- + net/sched/sch_codel.c | 14 ++++++++++---- + net/sched/sch_fq_codel.c | 24 +++++++++++++++--------- + 2 files changed, 25 insertions(+), 13 deletions(-) + +diff --git a/net/sched/sch_codel.c b/net/sched/sch_codel.c +index 30169b3adbbb..a2b81a5b2dfb 100644 +--- a/net/sched/sch_codel.c ++++ b/net/sched/sch_codel.c +@@ -95,11 +95,17 @@ static struct sk_buff *codel_qdisc_dequeue(struct Qdisc *sch) + &q->stats, qdisc_pkt_len, codel_get_enqueue_time, + drop_func, dequeue_func); + +- /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0, +- * or HTB crashes. Defer it for next round. ++ /* If our qlen is 0 qdisc_tree_reduce_backlog() will deactivate ++ * parent class, dequeue in parent qdisc will do the same if we ++ * return skb. Temporary increment qlen if we have skb. + */ +- if (q->stats.drop_count && sch->q.qlen) { +- qdisc_tree_reduce_backlog(sch, q->stats.drop_count, q->stats.drop_len); ++ if (q->stats.drop_count) { ++ if (skb) ++ sch->q.qlen++; ++ qdisc_tree_reduce_backlog(sch, q->stats.drop_count, ++ q->stats.drop_len); ++ if (skb) ++ sch->q.qlen--; + q->stats.drop_count = 0; + q->stats.drop_len = 0; + } +diff --git a/net/sched/sch_fq_codel.c b/net/sched/sch_fq_codel.c +index 839e1235db05..fd2620da04db 100644 +--- a/net/sched/sch_fq_codel.c ++++ b/net/sched/sch_fq_codel.c +@@ -304,6 +304,21 @@ static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch) + &flow->cvars, &q->cstats, qdisc_pkt_len, + codel_get_enqueue_time, drop_func, dequeue_func); + ++ /* If our qlen is 0 qdisc_tree_reduce_backlog() will deactivate ++ * parent class, dequeue in parent qdisc will do the same if we ++ * return skb. Temporary increment qlen if we have skb. ++ */ ++ if (q->cstats.drop_count) { ++ if (skb) ++ sch->q.qlen++; ++ qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, ++ q->cstats.drop_len); ++ if (skb) ++ sch->q.qlen--; ++ q->cstats.drop_count = 0; ++ q->cstats.drop_len = 0; ++ } ++ + if (!skb) { + /* force a pass through old_flows to prevent starvation */ + if ((head == &q->new_flows) && !list_empty(&q->old_flows)) +@@ -314,15 +329,6 @@ static struct sk_buff *fq_codel_dequeue(struct Qdisc *sch) + } + qdisc_bstats_update(sch, skb); + flow->deficit -= qdisc_pkt_len(skb); +- /* We cant call qdisc_tree_reduce_backlog() if our qlen is 0, +- * or HTB crashes. Defer it for next round. +- */ +- if (q->cstats.drop_count && sch->q.qlen) { +- qdisc_tree_reduce_backlog(sch, q->cstats.drop_count, +- q->cstats.drop_len); +- q->cstats.drop_count = 0; +- q->cstats.drop_len = 0; +- } + return skb; + } + +-- +2.37.2 + |