kernel: merge a pending fix for HFSC warnings/slowdowns (fixes FS#1136)

Signed-off-by: Felix Fietkau <nbd@nbd.name>
This commit is contained in:
Felix Fietkau 2018-03-10 10:09:07 +01:00
parent 4e8f1e9f4c
commit 9306bdf31c
9 changed files with 267 additions and 9 deletions

View file

@ -13,7 +13,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
--- a/net/sched/sch_fq_codel.c --- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c
@@ -465,7 +465,11 @@ static int fq_codel_init(struct Qdisc *s @@ -471,7 +471,11 @@ static int fq_codel_init(struct Qdisc *s
sch->limit = 10*1024; sch->limit = 10*1024;
q->flows_cnt = 1024; q->flows_cnt = 1024;

View file

@ -55,7 +55,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
register_qdisc(&pfifo_head_drop_qdisc_ops); register_qdisc(&pfifo_head_drop_qdisc_ops);
--- a/net/sched/sch_fq_codel.c --- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c
@@ -694,7 +694,7 @@ static const struct Qdisc_class_ops fq_c @@ -700,7 +700,7 @@ static const struct Qdisc_class_ops fq_c
.walk = fq_codel_walk, .walk = fq_codel_walk,
}; };
@ -64,7 +64,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
.cl_ops = &fq_codel_class_ops, .cl_ops = &fq_codel_class_ops,
.id = "fq_codel", .id = "fq_codel",
.priv_size = sizeof(struct fq_codel_sched_data), .priv_size = sizeof(struct fq_codel_sched_data),
@@ -709,6 +709,7 @@ static struct Qdisc_ops fq_codel_qdisc_o @@ -715,6 +715,7 @@ static struct Qdisc_ops fq_codel_qdisc_o
.dump_stats = fq_codel_dump_stats, .dump_stats = fq_codel_dump_stats,
.owner = THIS_MODULE, .owner = THIS_MODULE,
}; };

View file

@ -13,7 +13,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
--- a/net/sched/sch_fq_codel.c --- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c
@@ -479,7 +479,11 @@ static int fq_codel_init(struct Qdisc *s @@ -485,7 +485,11 @@ static int fq_codel_init(struct Qdisc *s
sch->limit = 10*1024; sch->limit = 10*1024;
q->flows_cnt = 1024; q->flows_cnt = 1024;

View file

@ -55,7 +55,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
register_qdisc(&pfifo_head_drop_qdisc_ops); register_qdisc(&pfifo_head_drop_qdisc_ops);
--- a/net/sched/sch_fq_codel.c --- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c
@@ -709,7 +709,7 @@ static const struct Qdisc_class_ops fq_c @@ -715,7 +715,7 @@ static const struct Qdisc_class_ops fq_c
.walk = fq_codel_walk, .walk = fq_codel_walk,
}; };
@ -64,7 +64,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
.cl_ops = &fq_codel_class_ops, .cl_ops = &fq_codel_class_ops,
.id = "fq_codel", .id = "fq_codel",
.priv_size = sizeof(struct fq_codel_sched_data), .priv_size = sizeof(struct fq_codel_sched_data),
@@ -724,6 +724,7 @@ static struct Qdisc_ops fq_codel_qdisc_o @@ -730,6 +730,7 @@ static struct Qdisc_ops fq_codel_qdisc_o
.dump_stats = fq_codel_dump_stats, .dump_stats = fq_codel_dump_stats,
.owner = THIS_MODULE, .owner = THIS_MODULE,
}; };

View file

@ -0,0 +1,86 @@
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Date: Mon, 21 Aug 2017 11:14:14 +0300
Subject: [PATCH] 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
---
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -95,11 +95,17 @@ static struct sk_buff *codel_qdisc_deque
&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;
}
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -316,6 +316,21 @@ begin:
flow->dropped += q->cstats.drop_count - prev_drop_count;
flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;
+ /* 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))
@@ -326,15 +341,6 @@ begin:
}
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;
}

View file

@ -0,0 +1,86 @@
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Date: Mon, 21 Aug 2017 11:14:14 +0300
Subject: [PATCH] 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
---
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -79,11 +79,17 @@ static struct sk_buff *codel_qdisc_deque
skb = codel_dequeue(sch, &q->params, &q->vars, &q->stats, dequeue);
- /* 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;
}
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -311,6 +311,21 @@ begin:
flow->dropped += q->cstats.drop_count - prev_drop_count;
flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;
+ /* 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))
@@ -321,15 +336,6 @@ begin:
}
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;
}

View file

@ -1,6 +1,6 @@
--- a/net/sched/sch_fq_codel.c --- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c
@@ -471,7 +471,7 @@ static int fq_codel_init(struct Qdisc *s @@ -477,7 +477,7 @@ static int fq_codel_init(struct Qdisc *s
sch->limit = 10*1024; sch->limit = 10*1024;
q->flows_cnt = 1024; q->flows_cnt = 1024;

View file

@ -13,7 +13,7 @@
device, it has to decide which ones to send first, which ones to device, it has to decide which ones to send first, which ones to
--- a/net/sched/sch_fq_codel.c --- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c +++ b/net/sched/sch_fq_codel.c
@@ -688,7 +688,7 @@ static const struct Qdisc_class_ops fq_c @@ -694,7 +694,7 @@ static const struct Qdisc_class_ops fq_c
.walk = fq_codel_walk, .walk = fq_codel_walk,
}; };
@ -22,7 +22,7 @@
.cl_ops = &fq_codel_class_ops, .cl_ops = &fq_codel_class_ops,
.id = "fq_codel", .id = "fq_codel",
.priv_size = sizeof(struct fq_codel_sched_data), .priv_size = sizeof(struct fq_codel_sched_data),
@@ -704,6 +704,7 @@ static struct Qdisc_ops fq_codel_qdisc_o @@ -710,6 +710,7 @@ static struct Qdisc_ops fq_codel_qdisc_o
.dump_stats = fq_codel_dump_stats, .dump_stats = fq_codel_dump_stats,
.owner = THIS_MODULE, .owner = THIS_MODULE,
}; };

View file

@ -0,0 +1,86 @@
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Date: Mon, 21 Aug 2017 11:14:14 +0300
Subject: [PATCH] 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
---
--- a/net/sched/sch_codel.c
+++ b/net/sched/sch_codel.c
@@ -95,11 +95,17 @@ static struct sk_buff *codel_qdisc_deque
&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;
}
--- a/net/sched/sch_fq_codel.c
+++ b/net/sched/sch_fq_codel.c
@@ -318,6 +318,21 @@ begin:
flow->dropped += q->cstats.drop_count - prev_drop_count;
flow->dropped += q->cstats.ecn_mark - prev_ecn_mark;
+ /* 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))
@@ -328,15 +343,6 @@ begin:
}
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;
}