target/linux/generic/patches-4.0/657-qdisc_reduce_truesize.patch

   1 From bc9fec2f87d57bdbff30d296605e24504513f65c Mon Sep 17 00:00:00 2001
   2 From: =?UTF-8?q?Dave=20T=C3=A4ht?= <dave.taht@bufferbloat.net>
   3 Date: Mon, 17 Sep 2012 19:20:22 -0700
   4 Subject: [PATCH 4/7] net: add skb_reduce_truesize support to common qdiscs
   5
   6 Reduce skb size under load when queues begin to fill on the
   7 commont qdiscs.
   8 ---
   9  net/sched/sch_codel.c    |    2 ++
  10  net/sched/sch_fifo.c     |   12 ++++++++----
  11  net/sched/sch_fq_codel.c |    2 ++
  12  3 files changed, 12 insertions(+), 4 deletions(-)
  13
  14 --- a/net/sched/sch_codel.c
  15 +++ b/net/sched/sch_codel.c
  16 @@ -96,6 +96,8 @@ static int codel_qdisc_enqueue(struct sk
  17         struct codel_sched_data *q;
  18
  19         if (likely(qdisc_qlen(sch) < sch->limit)) {
  20 +               if(qdisc_qlen(sch) > 128)
  21 +                       skb = skb_reduce_truesize(skb);
  22                 codel_set_enqueue_time(skb);
  23                 return qdisc_enqueue_tail(skb, sch);
  24         }
  25 --- a/net/sched/sch_fifo.c
  26 +++ b/net/sched/sch_fifo.c
  27 @@ -29,17 +29,21 @@ static int bfifo_enqueue(struct sk_buff
  28
  29  static int pfifo_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  30  {
  31 -       if (likely(skb_queue_len(&sch->q) < sch->limit))
  32 +       if (likely(skb_queue_len(&sch->q) < sch->limit)) {
  33 +               if (skb_queue_len(&sch->q) > 128)
  34 +                       skb = skb_reduce_truesize(skb);
  35                 return qdisc_enqueue_tail(skb, sch);
  36 -
  37 +       }
  38         return qdisc_reshape_fail(skb, sch);
  39  }
  40
  41  static int pfifo_tail_enqueue(struct sk_buff *skb, struct Qdisc *sch)
  42  {
  43 -       if (likely(skb_queue_len(&sch->q) < sch->limit))
  44 +       if (likely(skb_queue_len(&sch->q) < sch->limit)) {
  45 +               if (skb_queue_len(&sch->q) > 128)
  46 +                       skb = skb_reduce_truesize(skb);
  47                 return qdisc_enqueue_tail(skb, sch);
  48 -
  49 +       }
  50         /* queue full, remove one skb to fulfill the limit */
  51         __qdisc_queue_drop_head(sch, &sch->q);
  52         qdisc_qstats_drop(sch);
  53 --- a/net/sched/sch_fq_codel.c
  54 +++ b/net/sched/sch_fq_codel.c
  55 @@ -185,6 +185,8 @@ static int fq_codel_enqueue(struct sk_bu
  56                 return ret;
  57         }
  58         idx--;
  59 +       if (sch->q.qlen > 128)
  60 +               skb = skb_reduce_truesize(skb);
  61
  62         codel_set_enqueue_time(skb);
  63         flow = &q->flows[idx];