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         struct sk_buff *next;
 204         bool oom;
 205
 206         lockdep_assert_held(&fq->lock);
 207
 208         flow = fq_flow_classify(fq, tin, idx, skb);
 209
 210         if (!flow->backlog) {
 211                 if (flow != &tin->default_flow)
 212                         __set_bit(idx, fq->flows_bitmap);
 213                 else if (list_empty(&tin->tin_list))
 214                         list_add(&tin->tin_list, &fq->tin_backlog);
 215         }
 216
 217         flow->tin = tin;
 218         skb_list_walk_safe(skb, skb, next) {
 219                 skb_mark_not_on_list(skb);
 220                 flow->backlog += skb->len;
 221                 tin->backlog_bytes += skb->len;
 222                 tin->backlog_packets++;
 223                 fq->memory_usage += skb->truesize;
 224                 fq->backlog++;
 225                 __skb_queue_tail(&flow->queue, skb);
 226         }
 227
 228         if (list_empty(&flow->flowchain)) {
 229                 flow->deficit = fq->quantum;
 230                 list_add_tail(&flow->flowchain,
 231                               &tin->new_flows);
 232         }
 233
 234         oom = (fq->memory_usage > fq->memory_limit);
 235         while (fq->backlog > fq->limit || oom) {
 236                 flow = fq_find_fattest_flow(fq);
 237                 if (!flow)
 238                         return;
 239
 240                 if (!fq_flow_drop(fq, flow, free_func))
 241                         return;
 242
 243                 flow->tin->overlimit++;
 244                 fq->overlimit++;
 245                 if (oom) {
 246                         fq->overmemory++;
 247                         oom = (fq->memory_usage > fq->memory_limit);
 248                 }
 249         }
 250 }
 251
 252 static void fq_flow_filter(struct fq *fq,
 253                            struct fq_flow *flow,
 254                            fq_skb_filter_t filter_func,
 255                            void *filter_data,
 256                            fq_skb_free_t free_func)
 257 {
 258         struct fq_tin *tin = flow->tin;
 259         struct sk_buff *skb, *tmp;
 260
 261         lockdep_assert_held(&fq->lock);
 262
 263         skb_queue_walk_safe(&flow->queue, skb, tmp) {
 264                 if (!filter_func(fq, tin, flow, skb, filter_data))
 265                         continue;
 266
 267                 __skb_unlink(skb, &flow->queue);
 268                 fq_adjust_removal(fq, flow, skb);
 269                 free_func(fq, tin, flow, skb);
 270         }
 271 }
 272
 273 static void fq_tin_filter(struct fq *fq,
 274                           struct fq_tin *tin,
 275                           fq_skb_filter_t filter_func,
 276                           void *filter_data,
 277                           fq_skb_free_t free_func)
 278 {
 279         struct fq_flow *flow;
 280
 281         lockdep_assert_held(&fq->lock);
 282
 283         list_for_each_entry(flow, &tin->new_flows, flowchain)
 284                 fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
 285         list_for_each_entry(flow, &tin->old_flows, flowchain)
 286                 fq_flow_filter(fq, flow, filter_func, filter_data, free_func);
 287 }
 288
 289 static void fq_flow_reset(struct fq *fq,
 290                           struct fq_flow *flow,
 291                           fq_skb_free_t free_func)
 292 {
 293         struct fq_tin *tin = flow->tin;
 294         struct sk_buff *skb;
 295
 296         while ((skb = fq_flow_dequeue(fq, flow)))
 297                 free_func(fq, tin, flow, skb);
 298
 299         if (!list_empty(&flow->flowchain)) {
 300                 list_del_init(&flow->flowchain);
 301                 if (list_empty(&tin->new_flows) &&
 302                     list_empty(&tin->old_flows))
 303                         list_del_init(&tin->tin_list);
 304         }
 305
 306         flow->tin = NULL;
 307
 308         WARN_ON_ONCE(flow->backlog);
 309 }
 310
 311 static void fq_tin_reset(struct fq *fq,
 312                          struct fq_tin *tin,
 313                          fq_skb_free_t free_func)
 314 {
 315         struct list_head *head;
 316         struct fq_flow *flow;
 317
 318         for (;;) {
 319                 head = &tin->new_flows;
 320                 if (list_empty(head)) {
 321                         head = &tin->old_flows;
 322                         if (list_empty(head))
 323                                 break;
 324                 }
 325
 326                 flow = list_first_entry(head, struct fq_flow, flowchain);
 327                 fq_flow_reset(fq, flow, free_func);
 328         }
 329
 330         WARN_ON_ONCE(!list_empty(&tin->tin_list));
 331         WARN_ON_ONCE(tin->backlog_bytes);
 332         WARN_ON_ONCE(tin->backlog_packets);
 333 }
 334
 335 static void fq_flow_init(struct fq_flow *flow)
 336 {
 337         INIT_LIST_HEAD(&flow->flowchain);
 338         __skb_queue_head_init(&flow->queue);
 339 }
 340
 341 static void fq_tin_init(struct fq_tin *tin)
 342 {
 343         INIT_LIST_HEAD(&tin->new_flows);
 344         INIT_LIST_HEAD(&tin->old_flows);
 345         INIT_LIST_HEAD(&tin->tin_list);
 346         fq_flow_init(&tin->default_flow);
 347 }
 348
 349 static int fq_init(struct fq *fq, int flows_cnt)
 350 {
 351         int i;
 352
 353         memset(fq, 0, sizeof(fq[0]));
 354         spin_lock_init(&fq->lock);
 355         INIT_LIST_HEAD(&fq->tin_backlog);
 356         fq->flows_cnt = max_t(u32, flows_cnt, 1);
 357         fq->quantum = 300;
 358         fq->limit = 8192;
 359         fq->memory_limit = 16 << 20; /* 16 MBytes */
 360
 361         fq->flows = kvcalloc(fq->flows_cnt, sizeof(fq->flows[0]), GFP_KERNEL);
 362         if (!fq->flows)
 363                 return -ENOMEM;
 364
 365         fq->flows_bitmap = bitmap_zalloc(fq->flows_cnt, GFP_KERNEL);
 366         if (!fq->flows_bitmap) {
 367                 kvfree(fq->flows);
 368                 fq->flows = NULL;
 369                 return -ENOMEM;
 370         }
 371
 372         for (i = 0; i < fq->flows_cnt; i++)
 373                 fq_flow_init(&fq->flows[i]);
 374
 375         return 0;
 376 }
 377
 378 static void fq_reset(struct fq *fq,
 379                      fq_skb_free_t free_func)
 380 {
 381         int i;
 382
 383         for (i = 0; i < fq->flows_cnt; i++)
 384                 fq_flow_reset(fq, &fq->flows[i], free_func);
 385
 386         kvfree(fq->flows);
 387         fq->flows = NULL;
 388
 389         bitmap_free(fq->flows_bitmap);
 390         fq->flows_bitmap = NULL;
 391 }
 392
 393 #endif