kernel: merge a pending fix for HFSC warnings/slowdowns (fixes FS#1136)
authorFelix Fietkau <nbd@nbd.name>
Sat, 10 Mar 2018 09:09:07 +0000 (10:09 +0100)
committerFelix Fietkau <nbd@nbd.name>
Sun, 11 Mar 2018 07:58:53 +0000 (08:58 +0100)
Signed-off-by: Felix Fietkau <nbd@nbd.name>
target/linux/generic/hack-4.14/660-fq_codel_defaults.patch
target/linux/generic/hack-4.14/661-use_fq_codel_by_default.patch
target/linux/generic/hack-4.9/660-fq_codel_defaults.patch
target/linux/generic/hack-4.9/661-use_fq_codel_by_default.patch
target/linux/generic/pending-4.14/620-net_sched-codel-do-not-defer-queue-length-update.patch [new file with mode: 0644]
target/linux/generic/pending-4.4/620-net_sched-codel-do-not-defer-queue-length-update.patch [new file with mode: 0644]
target/linux/generic/pending-4.4/660-fq_codel_defaults.patch
target/linux/generic/pending-4.4/662-use_fq_codel_by_default.patch
target/linux/generic/pending-4.9/620-net_sched-codel-do-not-defer-queue-length-update.patch [new file with mode: 0644]

index 3e27351..b923a2d 100644 (file)
@@ -13,7 +13,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
 
 --- a/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;
        q->flows_cnt = 1024;
index e1eee00..5b61d74 100644 (file)
@@ -55,7 +55,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
        register_qdisc(&pfifo_head_drop_qdisc_ops);
 --- a/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,
  };
  
@@ -64,7 +64,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
        .cl_ops         =       &fq_codel_class_ops,
        .id             =       "fq_codel",
        .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,
        .owner          =       THIS_MODULE,
  };
index 3e64730..ea461e1 100644 (file)
@@ -13,7 +13,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
 
 --- a/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;
        q->flows_cnt = 1024;
index 7a249e3..981170c 100644 (file)
@@ -55,7 +55,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
        register_qdisc(&pfifo_head_drop_qdisc_ops);
 --- a/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,
  };
  
@@ -64,7 +64,7 @@ Signed-off-by: Felix Fietkau <nbd@nbd.name>
        .cl_ops         =       &fq_codel_class_ops,
        .id             =       "fq_codel",
        .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,
        .owner          =       THIS_MODULE,
  };
diff --git a/target/linux/generic/pending-4.14/620-net_sched-codel-do-not-defer-queue-length-update.patch b/target/linux/generic/pending-4.14/620-net_sched-codel-do-not-defer-queue-length-update.patch
new file mode 100644 (file)
index 0000000..b3c35ee
--- /dev/null
@@ -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;
+ }
diff --git a/target/linux/generic/pending-4.4/620-net_sched-codel-do-not-defer-queue-length-update.patch b/target/linux/generic/pending-4.4/620-net_sched-codel-do-not-defer-queue-length-update.patch
new file mode 100644 (file)
index 0000000..2ec9c7a
--- /dev/null
@@ -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;
+ }
index 46fceff..fbe9008 100644 (file)
@@ -1,6 +1,6 @@
 --- a/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;
        q->flows_cnt = 1024;
index 9d1962c..8d70b82 100644 (file)
@@ -13,7 +13,7 @@
          device, it has to decide which ones to send first, which ones to
 --- a/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,
  };
  
@@ -22,7 +22,7 @@
        .cl_ops         =       &fq_codel_class_ops,
        .id             =       "fq_codel",
        .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,
        .owner          =       THIS_MODULE,
  };
diff --git a/target/linux/generic/pending-4.9/620-net_sched-codel-do-not-defer-queue-length-update.patch b/target/linux/generic/pending-4.9/620-net_sched-codel-do-not-defer-queue-length-update.patch
new file mode 100644 (file)
index 0000000..6fe863a
--- /dev/null
@@ -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;
+ }