include/net/fq_impl.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  * Copyright (c) 2016 Qualcomm Atheros, Inc
   4  *
   5  * Based on net/sched/sch_fq_codel.c
   6  */
   7 #ifndef __NET_SCHED_FQ_IMPL_H
   8 #define __NET_SCHED_FQ_IMPL_H
   9
  10 #include <net/fq.h>
  11
  12 /* functions that are embedded into includer */
  13
  14
  15 static void
  16 __fq_adjust_removal(struct fq *fq, struct fq_flow *flow, unsigned int packets,
  17                     unsigned int bytes, unsigned int truesize)
  18 {
  19         struct fq_tin *tin = flow->tin;
  20         int idx;
  21
  22         tin->backlog_bytes -= bytes;
  23         tin->backlog_packets -= packets;
  24         flow->backlog -= bytes;
  25         fq->backlog -= packets;
  26         fq->memory_usage -= truesize;
  27
  28         if (flow->backlog)
  29                 return;
  30
  31         if (flow == &tin->default_flow) {
  32                 list_del_init(&tin->tin_list);
  33                 return;
  34         }
  35
  36         idx = flow - fq->flows;
  37         __clear_bit(idx, fq->flows_bitmap);
  38 }
  39
  40 static void fq_adjust_removal(struct fq *fq,
  41                               struct fq_flow *flow,
  42                               struct sk_buff *skb)
  43 {
  44         __fq_adjust_removal(fq, flow, 1, skb->len, skb->truesize);
  45 }
  46
  47 static struct sk_buff *fq_flow_dequeue(struct fq *fq,
  48                                        struct fq_flow *flow)
  49 {
  50         struct sk_buff *skb;
  51
  52         lockdep_assert_held(&fq->lock);
  53
  54         skb = __skb_dequeue(&flow->queue);
  55         if (!skb)
  56                 return NULL;
  57
  58         fq_adjust_removal(fq, flow, skb);
  59
  60         return skb;
  61 }
  62
  63 static int fq_flow_drop(struct fq *fq, struct fq_flow *flow,
  64                         fq_skb_free_t free_func)
  65 {
  66         unsigned int packets = 0, bytes = 0, truesize = 0;
  67         struct fq_tin *tin = flow->tin;
  68         struct sk_buff *skb;
  69         int pending;
  70
  71         lockdep_assert_held(&fq->lock);
  72
  73         pending = min_t(int, 32, skb_queue_len(&flow->queue) / 2);
  74         do {
  75                 skb = __skb_dequeue(&flow->queue);
  76                 if (!skb)
  77                         break;
  78
  79                 packets++;
  80                 bytes += skb->len;
  81                 truesize += skb->truesize;
  82                 free_func(fq, tin, flow, skb);
  83         } while (packets < pending);
  84
  85         __fq_adjust_removal(fq, flow, packets, bytes, truesize);
  86
  87         return packets;
  88 }
  89
  90 static struct sk_buff *fq_tin_dequeue(struct fq *fq,
  91                                       struct fq_tin *tin,
  92                                       fq_tin_dequeue_t dequeue_func)
  93 {
  94         struct fq_flow *flow;
  95         struct list_head *head;
  96         struct sk_buff *skb;
  97
  98         lockdep_assert_held(&fq->lock);
  99
 100 begin:
 101         head = &tin->new_flows;
 102         if (list_empty(head)) {
 103                 head = &tin->old_flows;
 104                 if (list_empty(head))
 105                         return NULL;
 106         }
 107
 108         flow = list_first_entry(head, struct fq_flow, flowchain);
 109
 110         if (flow->deficit <= 0) {
 111                 flow->deficit += fq->quantum;
 112                 list_move_tail(&flow->flowchain,
 113                                &tin->old_flows);
 114                 goto begin;
 115         }
 116
 117         skb = dequeue_func(fq, tin, flow);
 118         if (!skb) {
 119                 /* force a pass through old_flows to prevent starvation */
 120                 if ((head == &tin->new_flows) &&
 121                     !list_empty(&tin->old_flows)) {
 122                         list_move_tail(&flow->flowchain, &tin->old_flows);
 123                 } else {
 124                         list_del_init(&flow->flowchain);
 125                         flow->tin = NULL;
 126                 }
 127                 goto begin;
 128         }
 129
 130         flow->deficit -= skb->len;
 131         tin->tx_bytes += skb->len;
 132         tin->tx_packets++;
 133
 134         return skb;
 135 }
 136
 137 static u32 fq_flow_idx(struct fq *fq, struct sk_buff *skb)
 138 {
 139         u32 hash = skb_get_hash(skb);
 140
 141         return reciprocal_scale(hash, fq->flows_cnt);
 142 }
 143
 144 static struct fq_flow *fq_flow_classify(struct fq *fq,
 145                                         struct fq_tin *tin, u32 idx,
 146                                         struct sk_buff *skb)
 147 {
 148         struct fq_flow *flow;
 149
 150         lockdep_assert_held(&fq->lock);
 151
 152         flow = &fq->flows[idx];
 153         if (flow->tin && flow->tin != tin) {
 154                 flow = &tin->default_flow;
 155                 tin->collisions++;
 156                 fq->collisions++;
 157         }
 158
 159         if (!flow->tin)
 160                 tin->flows++;
 161
 162         return flow;
 163 }
 164
 165 static struct fq_flow *fq_find_fattest_flow(struct fq *fq)
 166 {
 167         struct fq_tin *tin;
 168         struct fq_flow *flow = NULL;
 169         u32 len = 0;
 170         int i;
 171
 172         for_each_set_bit(i, fq->flows_bitmap, fq->flows_cnt) {
 173                 struct fq_flow *cur = &fq->flows[i];
 174                 unsigned int cur_len;
 175
 176                 cur_len = cur->backlog;
 177                 if (cur_len <= len)
 178                         continue;
 179
 180                 flow = cur;
 181                 len = cur_len;
 182         }
 183
 184         list_for_each_entry(tin, &fq->tin_backlog, tin_list) {
 185                 unsigned int cur_len = tin->default_flow.backlog;
 186
 187                 if (cur_len <= len)
 188                         continue;
 189
 190                 flow = &tin->default_flow;
 191                 len = cur_len;
 192         }
 193
 194         return flow;
 195 }
 196
 197 static void fq_tin_enqueue(struct fq *fq,
 198                            struct fq_tin *tin, u32 idx,
 199                            struct sk_buff *skb,
 200                            fq_skb_free_t free_func)
 201 {
 202         struct fq_flow *flow;
 203         bool oom;
 204
 205         lockdep_assert_held(&fq->lock);
 206
 207         flow = fq_flow_classify(fq, tin, idx, skb);
 208
 209         if (!flow->backlog) {
 210                 if (flow != &tin->default_flow)
 211                         __set_bit(idx, fq->flows_bitmap);
 212                 else if (list_empty(&tin->tin_list))
 213                         list_add(&tin->tin_list, &fq->tin_backlog);
 214         }
 215
 216         flow->tin = tin;
 217         flow->backlog += skb->len;
 218         tin->backlog_bytes += skb->len;
 219         tin->backlog_packets++;
 220         fq->memory_usage += skb->truesize;
 221         fq->backlog++;
 222
 223         if (list_empty(&flow->flowchain)) {
 224                 flow->deficit = fq->quantum;
 225                 list_add_tail(&flow->flowchain,
 226                               &tin->new_flows);
 227         }
 228
 229         __skb_queue_tail(&flow->queue, skb);
 230         oom = (fq->memory_usage > fq->memory_limit);
 231         while (fq->backlog > fq->limit || oom) {
 232                 flow = fq_find_fattest_flow(fq);
 233                 if (!flow)
 234                         return;
 235
 236                 if (!fq_flow_drop(fq, flow, free_func))
 237                         return;
 238
 239                 flow->tin->overlimit++;
 240                 fq->overlimit++;
 241                 if (oom) {
 242                         fq->overmemory++;
 243                         oom = (fq->memory_usage > fq->memory_limit);
 244                 }
 245         }
 246 }
 247
 248 static void fq_flow_filter(struct fq *fq,
 249                            struct fq_flow *flow,
 250                            fq_skb_filter_t filter_func,
 251                            void *filter_data,
 252                            fq_skb_free_t free_func)
 253 {
 254         struct fq_tin *tin = flow->tin;
 255         struct sk_buff *skb, *tmp;
 256
 257         lockdep_assert_held(&fq->lock);
 258
 259         skb_queue_walk_safe(&flow->queue, skb, tmp) {
 260                 if (!filter_func(fq, tin, flow, skb, filter_data))
 261                         continue;
 262
 263                 __skb_unlink(skb, &flow->queue);
 264                 fq_adjust_removal(fq, flow, skb);
 265                 free_func(fq, tin, flow, skb);
 266         }
 267 }
 268
 269 static void fq_tin_filter(struct fq *fq,
 270                           struct fq_tin *tin,
 271                           fq_skb_filter_t filter_func,
 272                           void *filter_data,
 273                           fq_skb_free_t free_func)
 274 {
 275         struct fq_flow *flow;
 276
 277         lockdep_assert_held(&fq->lock);
 278
 279         list_for_each_entry(flow, &tin->new_flows, flowchain)
 280                 fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
 281         list_for_each_entry(flow, &tin->old_flows, flowchain)
 282                 fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
 283 }
 284
 285 static void fq_flow_reset(struct fq *fq,
 286                           struct fq_flow *flow,
 287                           fq_skb_free_t free_func)
 288 {
 289         struct fq_tin *tin = flow->tin;
 290         struct sk_buff *skb;
 291
 292         while ((skb = fq_flow_dequeue(fq, flow)))
 293                 free_func(fq, tin, flow, skb);
 294
 295         if (!list_empty(&flow->flowchain)) {
 296                 list_del_init(&flow->flowchain);
 297                 if (list_empty(&tin->new_flows) &&
 298                     list_empty(&tin->old_flows))
 299                         list_del_init(&tin->tin_list);
 300         }
 301
 302         flow->tin = NULL;
 303
 304         WARN_ON_ONCE(flow->backlog);
 305 }
 306
 307 static void fq_tin_reset(struct fq *fq,
 308                          struct fq_tin *tin,
 309                          fq_skb_free_t free_func)
 310 {
 311         struct list_head *head;
 312         struct fq_flow *flow;
 313
 314         for (;;) {
 315                 head = &tin->new_flows;
 316                 if (list_empty(head)) {
 317                         head = &tin->old_flows;
 318                         if (list_empty(head))
 319                                 break;
 320                 }
 321
 322                 flow = list_first_entry(head, struct fq_flow, flowchain);
 323                 fq_flow_reset(fq, flow, free_func);
 324         }
 325
 326         WARN_ON_ONCE(!list_empty(&tin->tin_list));
 327         WARN_ON_ONCE(tin->backlog_bytes);
 328         WARN_ON_ONCE(tin->backlog_packets);
 329 }
 330
 331 static void fq_flow_init(struct fq_flow *flow)
 332 {
 333         INIT_LIST_HEAD(&flow->flowchain);
 334         __skb_queue_head_init(&flow->queue);
 335 }
 336
 337 static void fq_tin_init(struct fq_tin *tin)
 338 {
 339         INIT_LIST_HEAD(&tin->new_flows);
 340         INIT_LIST_HEAD(&tin->old_flows);
 341         INIT_LIST_HEAD(&tin->tin_list);
 342         fq_flow_init(&tin->default_flow);
 343 }
 344
 345 static int fq_init(struct fq *fq, int flows_cnt)
 346 {
 347         int i;
 348
 349         memset(fq, 0, sizeof(fq[0]));
 350         spin_lock_init(&fq->lock);
 351         INIT_LIST_HEAD(&fq->tin_backlog);
 352         fq->flows_cnt = max_t(u32, flows_cnt, 1);
 353         fq->quantum = 300;
 354         fq->limit = 8192;
 355         fq->memory_limit = 16 << 20; /* 16 MBytes */
 356
 357         fq->flows = kvcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL);
 358         if (!fq->flows)
 359                 return -ENOMEM;
 360
 361         fq->flows_bitmap = kcalloc(BITS_TO_LONGS(fq->flows_cnt), sizeof(long),
 362                                    GFP_KERNEL);
 363         if (!fq->flows_bitmap) {
 364                 kvfree(fq->flows);
 365                 fq->flows = NULL;
 366                 return -ENOMEM;
 367         }
 368
 369         for (i = 0; i < fq->flows_cnt; i++)
 370                 fq_flow_init(&fq->flows[i]);
 371
 372         return 0;
 373 }
 374
 375 static void fq_reset(struct fq *fq,
 376                      fq_skb_free_t free_func)
 377 {
 378         int i;
 379
 380         for (i = 0; i < fq->flows_cnt; i++)
 381                 fq_flow_reset(fq, &fq->flows[i], free_func);
 382
 383         kvfree(fq->flows);
 384         fq->flows = NULL;
 385
 386         kfree(fq->flows_bitmap);
 387         fq->flows_bitmap = NULL;
 388 }
 389
 390 #endif