target/linux/generic/hack-5.4/662-remove_pfifo_fast.patch

   1 From b531d492d5ef1cf9dba0f4888eb5fd8624a6d762 Mon Sep 17 00:00:00 2001
   2 From: Felix Fietkau <nbd@nbd.name>
   3 Date: Fri, 7 Jul 2017 17:23:42 +0200
   4 Subject: net: sched: switch default qdisc from pfifo_fast to fq_codel and remove pfifo_fast
   5
   6 Signed-off-by: Felix Fietkau <nbd@nbd.name>
   7 ---
   8  net/sched/sch_generic.c | 140 ------------------------------------------------
   9  1 file changed, 140 deletions(-)
  10
  11 --- a/net/sched/sch_generic.c
  12 +++ b/net/sched/sch_generic.c
  13 @@ -620,230 +620,6 @@ struct Qdisc_ops noqueue_qdisc_ops __rea
  14         .owner          =       THIS_MODULE,
  15  };
  16
  17 -static const u8 prio2band[TC_PRIO_MAX + 1] = {
  18 -       1, 2, 2, 2, 1, 2, 0, 0 , 1, 1, 1, 1, 1, 1, 1, 1
  19 -};
  20 -
  21 -/* 3-band FIFO queue: old style, but should be a bit faster than
  22 -   generic prio+fifo combination.
  23 - */
  24 -
  25 -#define PFIFO_FAST_BANDS 3
  26 -
  27 -/*
  28 - * Private data for a pfifo_fast scheduler containing:
  29 - *     - rings for priority bands
  30 - */
  31 -struct pfifo_fast_priv {
  32 -       struct skb_array q[PFIFO_FAST_BANDS];
  33 -};
  34 -
  35 -static inline struct skb_array *band2list(struct pfifo_fast_priv *priv,
  36 -                                         int band)
  37 -{
  38 -       return &priv->q[band];
  39 -}
  40 -
  41 -static int pfifo_fast_enqueue(struct sk_buff *skb, struct Qdisc *qdisc,
  42 -                             struct sk_buff **to_free)
  43 -{
  44 -       int band = prio2band[skb->priority & TC_PRIO_MAX];
  45 -       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
  46 -       struct skb_array *q = band2list(priv, band);
  47 -       unsigned int pkt_len = qdisc_pkt_len(skb);
  48 -       int err;
  49 -
  50 -       err = skb_array_produce(q, skb);
  51 -
  52 -       if (unlikely(err)) {
  53 -               if (qdisc_is_percpu_stats(qdisc))
  54 -                       return qdisc_drop_cpu(skb, qdisc, to_free);
  55 -               else
  56 -                       return qdisc_drop(skb, qdisc, to_free);
  57 -       }
  58 -
  59 -       qdisc_update_stats_at_enqueue(qdisc, pkt_len);
  60 -       return NET_XMIT_SUCCESS;
  61 -}
  62 -
  63 -static struct sk_buff *pfifo_fast_dequeue(struct Qdisc *qdisc)
  64 -{
  65 -       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
  66 -       struct sk_buff *skb = NULL;
  67 -       bool need_retry = true;
  68 -       int band;
  69 -
  70 -retry:
  71 -       for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
  72 -               struct skb_array *q = band2list(priv, band);
  73 -
  74 -               if (__skb_array_empty(q))
  75 -                       continue;
  76 -
  77 -               skb = __skb_array_consume(q);
  78 -       }
  79 -       if (likely(skb)) {
  80 -               qdisc_update_stats_at_dequeue(qdisc, skb);
  81 -       } else if (need_retry &&
  82 -                  test_bit(__QDISC_STATE_MISSED, &qdisc->state)) {
  83 -               /* Delay clearing the STATE_MISSED here to reduce
  84 -                * the overhead of the second spin_trylock() in
  85 -                * qdisc_run_begin() and __netif_schedule() calling
  86 -                * in qdisc_run_end().
  87 -                */
  88 -               clear_bit(__QDISC_STATE_MISSED, &qdisc->state);
  89 -
  90 -               /* Make sure dequeuing happens after clearing
  91 -                * STATE_MISSED.
  92 -                */
  93 -               smp_mb__after_atomic();
  94 -
  95 -               need_retry = false;
  96 -
  97 -               goto retry;
  98 -       } else {
  99 -               WRITE_ONCE(qdisc->empty, true);
 100 -       }
 101 -
 102 -       return skb;
 103 -}
 104 -
 105 -static struct sk_buff *pfifo_fast_peek(struct Qdisc *qdisc)
 106 -{
 107 -       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 108 -       struct sk_buff *skb = NULL;
 109 -       int band;
 110 -
 111 -       for (band = 0; band < PFIFO_FAST_BANDS && !skb; band++) {
 112 -               struct skb_array *q = band2list(priv, band);
 113 -
 114 -               skb = __skb_array_peek(q);
 115 -       }
 116 -
 117 -       return skb;
 118 -}
 119 -
 120 -static void pfifo_fast_reset(struct Qdisc *qdisc)
 121 -{
 122 -       int i, band;
 123 -       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 124 -
 125 -       for (band = 0; band < PFIFO_FAST_BANDS; band++) {
 126 -               struct skb_array *q = band2list(priv, band);
 127 -               struct sk_buff *skb;
 128 -
 129 -               /* NULL ring is possible if destroy path is due to a failed
 130 -                * skb_array_init() in pfifo_fast_init() case.
 131 -                */
 132 -               if (!q->ring.queue)
 133 -                       continue;
 134 -
 135 -               while ((skb = __skb_array_consume(q)) != NULL)
 136 -                       kfree_skb(skb);
 137 -       }
 138 -
 139 -       if (qdisc_is_percpu_stats(qdisc)) {
 140 -               for_each_possible_cpu(i) {
 141 -                       struct gnet_stats_queue *q;
 142 -
 143 -                       q = per_cpu_ptr(qdisc->cpu_qstats, i);
 144 -                       q->backlog = 0;
 145 -                       q->qlen = 0;
 146 -               }
 147 -       }
 148 -}
 149 -
 150 -static int pfifo_fast_dump(struct Qdisc *qdisc, struct sk_buff *skb)
 151 -{
 152 -       struct tc_prio_qopt opt = { .bands = PFIFO_FAST_BANDS };
 153 -
 154 -       memcpy(&opt.priomap, prio2band, TC_PRIO_MAX + 1);
 155 -       if (nla_put(skb, TCA_OPTIONS, sizeof(opt), &opt))
 156 -               goto nla_put_failure;
 157 -       return skb->len;
 158 -
 159 -nla_put_failure:
 160 -       return -1;
 161 -}
 162 -
 163 -static int pfifo_fast_init(struct Qdisc *qdisc, struct nlattr *opt,
 164 -                          struct netlink_ext_ack *extack)
 165 -{
 166 -       unsigned int qlen = qdisc_dev(qdisc)->tx_queue_len;
 167 -       struct pfifo_fast_priv *priv = qdisc_priv(qdisc);
 168 -       int prio;
 169 -
 170 -       /* guard against zero length rings */
 171 -       if (!qlen)
 172 -               return -EINVAL;
 173 -
 174 -       for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 175 -               struct skb_array *q = band2list(priv, prio);
 176 -               int err;
 177 -
 178 -               err = skb_array_init(q, qlen, GFP_KERNEL);
 179 -               if (err)
 180 -                       return -ENOMEM;
 181 -       }
 182 -
 183 -       /* Can by-pass the queue discipline */
 184 -       qdisc->flags |= TCQ_F_CAN_BYPASS;
 185 -       return 0;
 186 -}
 187 -
 188 -static void pfifo_fast_destroy(struct Qdisc *sch)
 189 -{
 190 -       struct pfifo_fast_priv *priv = qdisc_priv(sch);
 191 -       int prio;
 192 -
 193 -       for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 194 -               struct skb_array *q = band2list(priv, prio);
 195 -
 196 -               /* NULL ring is possible if destroy path is due to a failed
 197 -                * skb_array_init() in pfifo_fast_init() case.
 198 -                */
 199 -               if (!q->ring.queue)
 200 -                       continue;
 201 -               /* Destroy ring but no need to kfree_skb because a call to
 202 -                * pfifo_fast_reset() has already done that work.
 203 -                */
 204 -               ptr_ring_cleanup(&q->ring, NULL);
 205 -       }
 206 -}
 207 -
 208 -static int pfifo_fast_change_tx_queue_len(struct Qdisc *sch,
 209 -                                         unsigned int new_len)
 210 -{
 211 -       struct pfifo_fast_priv *priv = qdisc_priv(sch);
 212 -       struct skb_array *bands[PFIFO_FAST_BANDS];
 213 -       int prio;
 214 -
 215 -       for (prio = 0; prio < PFIFO_FAST_BANDS; prio++) {
 216 -               struct skb_array *q = band2list(priv, prio);
 217 -
 218 -               bands[prio] = q;
 219 -       }
 220 -
 221 -       return skb_array_resize_multiple(bands, PFIFO_FAST_BANDS, new_len,
 222 -                                        GFP_KERNEL);
 223 -}
 224 -
 225 -struct Qdisc_ops pfifo_fast_ops __read_mostly = {
 226 -       .id             =       "pfifo_fast",
 227 -       .priv_size      =       sizeof(struct pfifo_fast_priv),
 228 -       .enqueue        =       pfifo_fast_enqueue,
 229 -       .dequeue        =       pfifo_fast_dequeue,
 230 -       .peek           =       pfifo_fast_peek,
 231 -       .init           =       pfifo_fast_init,
 232 -       .destroy        =       pfifo_fast_destroy,
 233 -       .reset          =       pfifo_fast_reset,
 234 -       .dump           =       pfifo_fast_dump,
 235 -       .change_tx_queue_len =  pfifo_fast_change_tx_queue_len,
 236 -       .owner          =       THIS_MODULE,
 237 -       .static_flags   =       TCQ_F_NOLOCK | TCQ_F_CPUSTATS,
 238 -};
 239 -EXPORT_SYMBOL(pfifo_fast_ops);
 240 -
 241  struct Qdisc *qdisc_alloc(struct netdev_queue *dev_queue,
 242                           const struct Qdisc_ops *ops,
 243                           struct netlink_ext_ack *extack)