package/kernel/mac80211/patches/subsys/310-net-fq_impl-bulk-free-packets-from-a-flow-on-overmem.patch

   1 From: Felix Fietkau <nbd@nbd.name>
   2 Date: Wed, 25 Nov 2020 18:03:46 +0100
   3 Subject: [PATCH] net/fq_impl: bulk-free packets from a flow on overmemory
   4
   5 This is similar to what sch_fq_codel does. It also amortizes the worst
   6 case cost of a follow-up patch that changes the selection of the biggest
   7 flow for dropping packets
   8
   9 Signed-off-by: Felix Fietkau <nbd@nbd.name>
  10 ---
  11
  12 --- a/include/net/fq_impl.h
  13 +++ b/include/net/fq_impl.h
  14 @@ -11,17 +11,25 @@
  15
  16  /* functions that are embedded into includer */
  17
  18 +
  19 +static void
  20 +__fq_adjust_removal(struct fq *fq, struct fq_flow *flow, unsigned int packets,
  21 +                   unsigned int bytes, unsigned int truesize)
  22 +{
  23 +       struct fq_tin *tin = flow->tin;
  24 +
  25 +       tin->backlog_bytes -= bytes;
  26 +       tin->backlog_packets -= packets;
  27 +       flow->backlog -= bytes;
  28 +       fq->backlog -= packets;
  29 +       fq->memory_usage -= truesize;
  30 +}
  31 +
  32  static void fq_adjust_removal(struct fq *fq,
  33                               struct fq_flow *flow,
  34                               struct sk_buff *skb)
  35  {
  36 -       struct fq_tin *tin = flow->tin;
  37 -
  38 -       tin->backlog_bytes -= skb->len;
  39 -       tin->backlog_packets--;
  40 -       flow->backlog -= skb->len;
  41 -       fq->backlog--;
  42 -       fq->memory_usage -= skb->truesize;
  43 +       __fq_adjust_removal(fq, flow, 1, skb->len, skb->truesize);
  44  }
  45
  46  static void fq_rejigger_backlog(struct fq *fq, struct fq_flow *flow)
  47 @@ -59,6 +67,34 @@ static struct sk_buff *fq_flow_dequeue(s
  48         return skb;
  49  }
  50
  51 +static int fq_flow_drop(struct fq *fq, struct fq_flow *flow,
  52 +                       fq_skb_free_t free_func)
  53 +{
  54 +       unsigned int packets = 0, bytes = 0, truesize = 0;
  55 +       struct fq_tin *tin = flow->tin;
  56 +       struct sk_buff *skb;
  57 +       int pending;
  58 +
  59 +       lockdep_assert_held(&fq->lock);
  60 +
  61 +       pending = min_t(int, 32, skb_queue_len(&flow->queue) / 2);
  62 +       do {
  63 +               skb = __skb_dequeue(&flow->queue);
  64 +               if (!skb)
  65 +                       break;
  66 +
  67 +               packets++;
  68 +               bytes += skb->len;
  69 +               truesize += skb->truesize;
  70 +               free_func(fq, tin, flow, skb);
  71 +       } while (packets < pending);
  72 +
  73 +       __fq_adjust_removal(fq, flow, packets, bytes, truesize);
  74 +       fq_rejigger_backlog(fq, flow);
  75 +
  76 +       return packets;
  77 +}
  78 +
  79  static struct sk_buff *fq_tin_dequeue(struct fq *fq,
  80                                       struct fq_tin *tin,
  81                                       fq_tin_dequeue_t dequeue_func)
  82 @@ -190,12 +226,9 @@ static void fq_tin_enqueue(struct fq *fq
  83                 if (!flow)
  84                         return;
  85
  86 -               skb = fq_flow_dequeue(fq, flow);
  87 -               if (!skb)
  88 +               if (!fq_flow_drop(fq, flow, free_func))
  89                         return;
  90
  91 -               free_func(fq, flow->tin, flow, skb);
  92 -
  93                 flow->tin->overlimit++;
  94                 fq->overlimit++;
  95                 if (oom) {