include/net/fq_impl.h

   1 /*
   2  * Copyright (c) 2016 Qualcomm Atheros, Inc
   3  *
   4  * GPL v2
   5  *
   6  * Based on net/sched/sch_fq_codel.c
   7  */
   8 #ifndef __NET_SCHED_FQ_IMPL_H
   9 #define __NET_SCHED_FQ_IMPL_H
  10
  11 #include <net/fq.h>
  12
  13 /* functions that are embedded into includer */
  14
  15 static struct sk_buff *fq_flow_dequeue(struct fq *fq,
  16                                        struct fq_flow *flow)
  17 {
  18         struct fq_tin *tin = flow->tin;
  19         struct fq_flow *i;
  20         struct sk_buff *skb;
  21
  22         lockdep_assert_held(&fq->lock);
  23
  24         skb = __skb_dequeue(&flow->queue);
  25         if (!skb)
  26                 return NULL;
  27
  28         tin->backlog_bytes -= skb->len;
  29         tin->backlog_packets--;
  30         flow->backlog -= skb->len;
  31         fq->backlog--;
  32
  33         if (flow->backlog == 0) {
  34                 list_del_init(&flow->backlogchain);
  35         } else {
  36                 i = flow;
  37
  38                 list_for_each_entry_continue(i, &fq->backlogs, backlogchain)
  39                         if (i->backlog < flow->backlog)
  40                                 break;
  41
  42                 list_move_tail(&flow->backlogchain,
  43                                &i->backlogchain);
  44         }
  45
  46         return skb;
  47 }
  48
  49 static struct sk_buff *fq_tin_dequeue(struct fq *fq,
  50                                       struct fq_tin *tin,
  51                                       fq_tin_dequeue_t dequeue_func)
  52 {
  53         struct fq_flow *flow;
  54         struct list_head *head;
  55         struct sk_buff *skb;
  56
  57         lockdep_assert_held(&fq->lock);
  58
  59 begin:
  60         head = &tin->new_flows;
  61         if (list_empty(head)) {
  62                 head = &tin->old_flows;
  63                 if (list_empty(head))
  64                         return NULL;
  65         }
  66
  67         flow = list_first_entry(head, struct fq_flow, flowchain);
  68
  69         if (flow->deficit <= 0) {
  70                 flow->deficit += fq->quantum;
  71                 list_move_tail(&flow->flowchain,
  72                                &tin->old_flows);
  73                 goto begin;
  74         }
  75
  76         skb = dequeue_func(fq, tin, flow);
  77         if (!skb) {
  78                 /* force a pass through old_flows to prevent starvation */
  79                 if ((head == &tin->new_flows) &&
  80                     !list_empty(&tin->old_flows)) {
  81                         list_move_tail(&flow->flowchain, &tin->old_flows);
  82                 } else {
  83                         list_del_init(&flow->flowchain);
  84                         flow->tin = NULL;
  85                 }
  86                 goto begin;
  87         }
  88
  89         flow->deficit -= skb->len;
  90         tin->tx_bytes += skb->len;
  91         tin->tx_packets++;
  92
  93         return skb;
  94 }
  95
  96 static struct fq_flow *fq_flow_classify(struct fq *fq,
  97                                         struct fq_tin *tin,
  98                                         struct sk_buff *skb,
  99                                         fq_flow_get_default_t get_default_func)
 100 {
 101         struct fq_flow *flow;
 102         u32 hash;
 103         u32 idx;
 104
 105         lockdep_assert_held(&fq->lock);
 106
 107         hash = skb_get_hash_perturb(skb, fq->perturbation);
 108         idx = reciprocal_scale(hash, fq->flows_cnt);
 109         flow = &fq->flows[idx];
 110
 111         if (flow->tin && flow->tin != tin) {
 112                 flow = get_default_func(fq, tin, idx, skb);
 113                 tin->collisions++;
 114                 fq->collisions++;
 115         }
 116
 117         if (!flow->tin)
 118                 tin->flows++;
 119
 120         return flow;
 121 }
 122
 123 static void fq_recalc_backlog(struct fq *fq,
 124                               struct fq_tin *tin,
 125                               struct fq_flow *flow)
 126 {
 127         struct fq_flow *i;
 128
 129         if (list_empty(&flow->backlogchain))
 130                 list_add_tail(&flow->backlogchain, &fq->backlogs);
 131
 132         i = flow;
 133         list_for_each_entry_continue_reverse(i, &fq->backlogs,
 134                                              backlogchain)
 135                 if (i->backlog > flow->backlog)
 136                         break;
 137
 138         list_move(&flow->backlogchain, &i->backlogchain);
 139 }
 140
 141 static void fq_tin_enqueue(struct fq *fq,
 142                            struct fq_tin *tin,
 143                            struct sk_buff *skb,
 144                            fq_skb_free_t free_func,
 145                            fq_flow_get_default_t get_default_func)
 146 {
 147         struct fq_flow *flow;
 148
 149         lockdep_assert_held(&fq->lock);
 150
 151         flow = fq_flow_classify(fq, tin, skb, get_default_func);
 152
 153         flow->tin = tin;
 154         flow->backlog += skb->len;
 155         tin->backlog_bytes += skb->len;
 156         tin->backlog_packets++;
 157         fq->backlog++;
 158
 159         fq_recalc_backlog(fq, tin, flow);
 160
 161         if (list_empty(&flow->flowchain)) {
 162                 flow->deficit = fq->quantum;
 163                 list_add_tail(&flow->flowchain,
 164                               &tin->new_flows);
 165         }
 166
 167         __skb_queue_tail(&flow->queue, skb);
 168
 169         if (fq->backlog > fq->limit) {
 170                 flow = list_first_entry_or_null(&fq->backlogs,
 171                                                 struct fq_flow,
 172                                                 backlogchain);
 173                 if (!flow)
 174                         return;
 175
 176                 skb = fq_flow_dequeue(fq, flow);
 177                 if (!skb)
 178                         return;
 179
 180                 free_func(fq, flow->tin, flow, skb);
 181
 182                 flow->tin->overlimit++;
 183                 fq->overlimit++;
 184         }
 185 }
 186
 187 static void fq_flow_reset(struct fq *fq,
 188                           struct fq_flow *flow,
 189                           fq_skb_free_t free_func)
 190 {
 191         struct sk_buff *skb;
 192
 193         while ((skb = fq_flow_dequeue(fq, flow)))
 194                 free_func(fq, flow->tin, flow, skb);
 195
 196         if (!list_empty(&flow->flowchain))
 197                 list_del_init(&flow->flowchain);
 198
 199         if (!list_empty(&flow->backlogchain))
 200                 list_del_init(&flow->backlogchain);
 201
 202         flow->tin = NULL;
 203
 204         WARN_ON_ONCE(flow->backlog);
 205 }
 206
 207 static void fq_tin_reset(struct fq *fq,
 208                          struct fq_tin *tin,
 209                          fq_skb_free_t free_func)
 210 {
 211         struct list_head *head;
 212         struct fq_flow *flow;
 213
 214         for (;;) {
 215                 head = &tin->new_flows;
 216                 if (list_empty(head)) {
 217                         head = &tin->old_flows;
 218                         if (list_empty(head))
 219                                 break;
 220                 }
 221
 222                 flow = list_first_entry(head, struct fq_flow, flowchain);
 223                 fq_flow_reset(fq, flow, free_func);
 224         }
 225
 226         WARN_ON_ONCE(tin->backlog_bytes);
 227         WARN_ON_ONCE(tin->backlog_packets);
 228 }
 229
 230 static void fq_flow_init(struct fq_flow *flow)
 231 {
 232         INIT_LIST_HEAD(&flow->flowchain);
 233         INIT_LIST_HEAD(&flow->backlogchain);
 234         __skb_queue_head_init(&flow->queue);
 235 }
 236
 237 static void fq_tin_init(struct fq_tin *tin)
 238 {
 239         INIT_LIST_HEAD(&tin->new_flows);
 240         INIT_LIST_HEAD(&tin->old_flows);
 241 }
 242
 243 static int fq_init(struct fq *fq, int flows_cnt)
 244 {
 245         int i;
 246
 247         memset(fq, 0, sizeof(fq[0]));
 248         INIT_LIST_HEAD(&fq->backlogs);
 249         spin_lock_init(&fq->lock);
 250         fq->flows_cnt = max_t(u32, flows_cnt, 1);
 251         fq->perturbation = prandom_u32();
 252         fq->quantum = 300;
 253         fq->limit = 8192;
 254
 255         fq->flows = kcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL);
 256         if (!fq->flows)
 257                 return -ENOMEM;
 258
 259         for (i = 0; i < fq->flows_cnt; i++)
 260                 fq_flow_init(&fq->flows[i]);
 261
 262         return 0;
 263 }
 264
 265 static void fq_reset(struct fq *fq,
 266                      fq_skb_free_t free_func)
 267 {
 268         int i;
 269
 270         for (i = 0; i < fq->flows_cnt; i++)
 271                 fq_flow_reset(fq, &fq->flows[i], free_func);
 272
 273         kfree(fq->flows);
 274         fq->flows = NULL;
 275 }
 276
 277 #endif