kernel/bpf/bpf_lru_list.c

   1 /* Copyright (c) 2016 Facebook
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  */
   7 #include <linux/cpumask.h>
   8 #include <linux/spinlock.h>
   9 #include <linux/percpu.h>
  10
  11 #include "bpf_lru_list.h"
  12
  13 #define LOCAL_FREE_TARGET               (128)
  14 #define LOCAL_NR_SCANS                  LOCAL_FREE_TARGET
  15
  16 #define PERCPU_FREE_TARGET              (4)
  17 #define PERCPU_NR_SCANS                 PERCPU_FREE_TARGET
  18
  19 /* Helpers to get the local list index */
  20 #define LOCAL_LIST_IDX(t)       ((t) - BPF_LOCAL_LIST_T_OFFSET)
  21 #define LOCAL_FREE_LIST_IDX     LOCAL_LIST_IDX(BPF_LRU_LOCAL_LIST_T_FREE)
  22 #define LOCAL_PENDING_LIST_IDX  LOCAL_LIST_IDX(BPF_LRU_LOCAL_LIST_T_PENDING)
  23 #define IS_LOCAL_LIST_TYPE(t)   ((t) >= BPF_LOCAL_LIST_T_OFFSET)
  24
  25 static int get_next_cpu(int cpu)
  26 {
  27         cpu = cpumask_next(cpu, cpu_possible_mask);
  28         if (cpu >= nr_cpu_ids)
  29                 cpu = cpumask_first(cpu_possible_mask);
  30         return cpu;
  31 }
  32
  33 /* Local list helpers */
  34 static struct list_head *local_free_list(struct bpf_lru_locallist *loc_l)
  35 {
  36         return &loc_l->lists[LOCAL_FREE_LIST_IDX];
  37 }
  38
  39 static struct list_head *local_pending_list(struct bpf_lru_locallist *loc_l)
  40 {
  41         return &loc_l->lists[LOCAL_PENDING_LIST_IDX];
  42 }
  43
  44 /* bpf_lru_node helpers */
  45 static bool bpf_lru_node_is_ref(const struct bpf_lru_node *node)
  46 {
  47         return node->ref;
  48 }
  49
  50 static void bpf_lru_list_count_inc(struct bpf_lru_list *l,
  51                                    enum bpf_lru_list_type type)
  52 {
  53         if (type < NR_BPF_LRU_LIST_COUNT)
  54                 l->counts[type]++;
  55 }
  56
  57 static void bpf_lru_list_count_dec(struct bpf_lru_list *l,
  58                                    enum bpf_lru_list_type type)
  59 {
  60         if (type < NR_BPF_LRU_LIST_COUNT)
  61                 l->counts[type]--;
  62 }
  63
  64 static void __bpf_lru_node_move_to_free(struct bpf_lru_list *l,
  65                                         struct bpf_lru_node *node,
  66                                         struct list_head *free_list,
  67                                         enum bpf_lru_list_type tgt_free_type)
  68 {
  69         if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)))
  70                 return;
  71
  72         /* If the removing node is the next_inactive_rotation candidate,
  73          * move the next_inactive_rotation pointer also.
  74          */
  75         if (&node->list == l->next_inactive_rotation)
  76                 l->next_inactive_rotation = l->next_inactive_rotation->prev;
  77
  78         bpf_lru_list_count_dec(l, node->type);
  79
  80         node->type = tgt_free_type;
  81         list_move(&node->list, free_list);
  82 }
  83
  84 /* Move nodes from local list to the LRU list */
  85 static void __bpf_lru_node_move_in(struct bpf_lru_list *l,
  86                                    struct bpf_lru_node *node,
  87                                    enum bpf_lru_list_type tgt_type)
  88 {
  89         if (WARN_ON_ONCE(!IS_LOCAL_LIST_TYPE(node->type)) ||
  90             WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(tgt_type)))
  91                 return;
  92
  93         bpf_lru_list_count_inc(l, tgt_type);
  94         node->type = tgt_type;
  95         node->ref = 0;
  96         list_move(&node->list, &l->lists[tgt_type]);
  97 }
  98
  99 /* Move nodes between or within active and inactive list (like
 100  * active to inactive, inactive to active or tail of active back to
 101  * the head of active).
 102  */
 103 static void __bpf_lru_node_move(struct bpf_lru_list *l,
 104                                 struct bpf_lru_node *node,
 105                                 enum bpf_lru_list_type tgt_type)
 106 {
 107         if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)) ||
 108             WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(tgt_type)))
 109                 return;
 110
 111         if (node->type != tgt_type) {
 112                 bpf_lru_list_count_dec(l, node->type);
 113                 bpf_lru_list_count_inc(l, tgt_type);
 114                 node->type = tgt_type;
 115         }
 116         node->ref = 0;
 117
 118         /* If the moving node is the next_inactive_rotation candidate,
 119          * move the next_inactive_rotation pointer also.
 120          */
 121         if (&node->list == l->next_inactive_rotation)
 122                 l->next_inactive_rotation = l->next_inactive_rotation->prev;
 123
 124         list_move(&node->list, &l->lists[tgt_type]);
 125 }
 126
 127 static bool bpf_lru_list_inactive_low(const struct bpf_lru_list *l)
 128 {
 129         return l->counts[BPF_LRU_LIST_T_INACTIVE] <
 130                 l->counts[BPF_LRU_LIST_T_ACTIVE];
 131 }
 132
 133 /* Rotate the active list:
 134  * 1. Start from tail
 135  * 2. If the node has the ref bit set, it will be rotated
 136  *    back to the head of active list with the ref bit cleared.
 137  *    Give this node one more chance to survive in the active list.
 138  * 3. If the ref bit is not set, move it to the head of the
 139  *    inactive list.
 140  * 4. It will at most scan nr_scans nodes
 141  */
 142 static void __bpf_lru_list_rotate_active(struct bpf_lru *lru,
 143                                          struct bpf_lru_list *l)
 144 {
 145         struct list_head *active = &l->lists[BPF_LRU_LIST_T_ACTIVE];
 146         struct bpf_lru_node *node, *tmp_node, *first_node;
 147         unsigned int i = 0;
 148
 149         first_node = list_first_entry(active, struct bpf_lru_node, list);
 150         list_for_each_entry_safe_reverse(node, tmp_node, active, list) {
 151                 if (bpf_lru_node_is_ref(node))
 152                         __bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
 153                 else
 154                         __bpf_lru_node_move(l, node, BPF_LRU_LIST_T_INACTIVE);
 155
 156                 if (++i == lru->nr_scans || node == first_node)
 157                         break;
 158         }
 159 }
 160
 161 /* Rotate the inactive list.  It starts from the next_inactive_rotation
 162  * 1. If the node has ref bit set, it will be moved to the head
 163  *    of active list with the ref bit cleared.
 164  * 2. If the node does not have ref bit set, it will leave it
 165  *    at its current location (i.e. do nothing) so that it can
 166  *    be considered during the next inactive_shrink.
 167  * 3. It will at most scan nr_scans nodes
 168  */
 169 static void __bpf_lru_list_rotate_inactive(struct bpf_lru *lru,
 170                                            struct bpf_lru_list *l)
 171 {
 172         struct list_head *inactive = &l->lists[BPF_LRU_LIST_T_INACTIVE];
 173         struct list_head *cur, *last, *next = inactive;
 174         struct bpf_lru_node *node;
 175         unsigned int i = 0;
 176
 177         if (list_empty(inactive))
 178                 return;
 179
 180         last = l->next_inactive_rotation->next;
 181         if (last == inactive)
 182                 last = last->next;
 183
 184         cur = l->next_inactive_rotation;
 185         while (i < lru->nr_scans) {
 186                 if (cur == inactive) {
 187                         cur = cur->prev;
 188                         continue;
 189                 }
 190
 191                 node = list_entry(cur, struct bpf_lru_node, list);
 192                 next = cur->prev;
 193                 if (bpf_lru_node_is_ref(node))
 194                         __bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
 195                 if (cur == last)
 196                         break;
 197                 cur = next;
 198                 i++;
 199         }
 200
 201         l->next_inactive_rotation = next;
 202 }
 203
 204 /* Shrink the inactive list.  It starts from the tail of the
 205  * inactive list and only move the nodes without the ref bit
 206  * set to the designated free list.
 207  */
 208 static unsigned int
 209 __bpf_lru_list_shrink_inactive(struct bpf_lru *lru,
 210                                struct bpf_lru_list *l,
 211                                unsigned int tgt_nshrink,
 212                                struct list_head *free_list,
 213                                enum bpf_lru_list_type tgt_free_type)
 214 {
 215         struct list_head *inactive = &l->lists[BPF_LRU_LIST_T_INACTIVE];
 216         struct bpf_lru_node *node, *tmp_node;
 217         unsigned int nshrinked = 0;
 218         unsigned int i = 0;
 219
 220         list_for_each_entry_safe_reverse(node, tmp_node, inactive, list) {
 221                 if (bpf_lru_node_is_ref(node)) {
 222                         __bpf_lru_node_move(l, node, BPF_LRU_LIST_T_ACTIVE);
 223                 } else if (lru->del_from_htab(lru->del_arg, node)) {
 224                         __bpf_lru_node_move_to_free(l, node, free_list,
 225                                                     tgt_free_type);
 226                         if (++nshrinked == tgt_nshrink)
 227                                 break;
 228                 }
 229
 230                 if (++i == lru->nr_scans)
 231                         break;
 232         }
 233
 234         return nshrinked;
 235 }
 236
 237 /* 1. Rotate the active list (if needed)
 238  * 2. Always rotate the inactive list
 239  */
 240 static void __bpf_lru_list_rotate(struct bpf_lru *lru, struct bpf_lru_list *l)
 241 {
 242         if (bpf_lru_list_inactive_low(l))
 243                 __bpf_lru_list_rotate_active(lru, l);
 244
 245         __bpf_lru_list_rotate_inactive(lru, l);
 246 }
 247
 248 /* Calls __bpf_lru_list_shrink_inactive() to shrink some
 249  * ref-bit-cleared nodes and move them to the designated
 250  * free list.
 251  *
 252  * If it cannot get a free node after calling
 253  * __bpf_lru_list_shrink_inactive().  It will just remove
 254  * one node from either inactive or active list without
 255  * honoring the ref-bit.  It prefers inactive list to active
 256  * list in this situation.
 257  */
 258 static unsigned int __bpf_lru_list_shrink(struct bpf_lru *lru,
 259                                           struct bpf_lru_list *l,
 260                                           unsigned int tgt_nshrink,
 261                                           struct list_head *free_list,
 262                                           enum bpf_lru_list_type tgt_free_type)
 263
 264 {
 265         struct bpf_lru_node *node, *tmp_node;
 266         struct list_head *force_shrink_list;
 267         unsigned int nshrinked;
 268
 269         nshrinked = __bpf_lru_list_shrink_inactive(lru, l, tgt_nshrink,
 270                                                    free_list, tgt_free_type);
 271         if (nshrinked)
 272                 return nshrinked;
 273
 274         /* Do a force shrink by ignoring the reference bit */
 275         if (!list_empty(&l->lists[BPF_LRU_LIST_T_INACTIVE]))
 276                 force_shrink_list = &l->lists[BPF_LRU_LIST_T_INACTIVE];
 277         else
 278                 force_shrink_list = &l->lists[BPF_LRU_LIST_T_ACTIVE];
 279
 280         list_for_each_entry_safe_reverse(node, tmp_node, force_shrink_list,
 281                                          list) {
 282                 if (lru->del_from_htab(lru->del_arg, node)) {
 283                         __bpf_lru_node_move_to_free(l, node, free_list,
 284                                                     tgt_free_type);
 285                         return 1;
 286                 }
 287         }
 288
 289         return 0;
 290 }
 291
 292 /* Flush the nodes from the local pending list to the LRU list */
 293 static void __local_list_flush(struct bpf_lru_list *l,
 294                                struct bpf_lru_locallist *loc_l)
 295 {
 296         struct bpf_lru_node *node, *tmp_node;
 297
 298         list_for_each_entry_safe_reverse(node, tmp_node,
 299                                          local_pending_list(loc_l), list) {
 300                 if (bpf_lru_node_is_ref(node))
 301                         __bpf_lru_node_move_in(l, node, BPF_LRU_LIST_T_ACTIVE);
 302                 else
 303                         __bpf_lru_node_move_in(l, node,
 304                                                BPF_LRU_LIST_T_INACTIVE);
 305         }
 306 }
 307
 308 static void bpf_lru_list_push_free(struct bpf_lru_list *l,
 309                                    struct bpf_lru_node *node)
 310 {
 311         unsigned long flags;
 312
 313         if (WARN_ON_ONCE(IS_LOCAL_LIST_TYPE(node->type)))
 314                 return;
 315
 316         raw_spin_lock_irqsave(&l->lock, flags);
 317         __bpf_lru_node_move(l, node, BPF_LRU_LIST_T_FREE);
 318         raw_spin_unlock_irqrestore(&l->lock, flags);
 319 }
 320
 321 static void bpf_lru_list_pop_free_to_local(struct bpf_lru *lru,
 322                                            struct bpf_lru_locallist *loc_l)
 323 {
 324         struct bpf_lru_list *l = &lru->common_lru.lru_list;
 325         struct bpf_lru_node *node, *tmp_node;
 326         unsigned int nfree = 0;
 327
 328         raw_spin_lock(&l->lock);
 329
 330         __local_list_flush(l, loc_l);
 331
 332         __bpf_lru_list_rotate(lru, l);
 333
 334         list_for_each_entry_safe(node, tmp_node, &l->lists[BPF_LRU_LIST_T_FREE],
 335                                  list) {
 336                 __bpf_lru_node_move_to_free(l, node, local_free_list(loc_l),
 337                                             BPF_LRU_LOCAL_LIST_T_FREE);
 338                 if (++nfree == LOCAL_FREE_TARGET)
 339                         break;
 340         }
 341
 342         if (nfree < LOCAL_FREE_TARGET)
 343                 __bpf_lru_list_shrink(lru, l, LOCAL_FREE_TARGET - nfree,
 344                                       local_free_list(loc_l),
 345                                       BPF_LRU_LOCAL_LIST_T_FREE);
 346
 347         raw_spin_unlock(&l->lock);
 348 }
 349
 350 static void __local_list_add_pending(struct bpf_lru *lru,
 351                                      struct bpf_lru_locallist *loc_l,
 352                                      int cpu,
 353                                      struct bpf_lru_node *node,
 354                                      u32 hash)
 355 {
 356         *(u32 *)((void *)node + lru->hash_offset) = hash;
 357         node->cpu = cpu;
 358         node->type = BPF_LRU_LOCAL_LIST_T_PENDING;
 359         node->ref = 0;
 360         list_add(&node->list, local_pending_list(loc_l));
 361 }
 362
 363 static struct bpf_lru_node *
 364 __local_list_pop_free(struct bpf_lru_locallist *loc_l)
 365 {
 366         struct bpf_lru_node *node;
 367
 368         node = list_first_entry_or_null(local_free_list(loc_l),
 369                                         struct bpf_lru_node,
 370                                         list);
 371         if (node)
 372                 list_del(&node->list);
 373
 374         return node;
 375 }
 376
 377 static struct bpf_lru_node *
 378 __local_list_pop_pending(struct bpf_lru *lru, struct bpf_lru_locallist *loc_l)
 379 {
 380         struct bpf_lru_node *node;
 381         bool force = false;
 382
 383 ignore_ref:
 384         /* Get from the tail (i.e. older element) of the pending list. */
 385         list_for_each_entry_reverse(node, local_pending_list(loc_l),
 386                                     list) {
 387                 if ((!bpf_lru_node_is_ref(node) || force) &&
 388                     lru->del_from_htab(lru->del_arg, node)) {
 389                         list_del(&node->list);
 390                         return node;
 391                 }
 392         }
 393
 394         if (!force) {
 395                 force = true;
 396                 goto ignore_ref;
 397         }
 398
 399         return NULL;
 400 }
 401
 402 static struct bpf_lru_node *bpf_percpu_lru_pop_free(struct bpf_lru *lru,
 403                                                     u32 hash)
 404 {
 405         struct list_head *free_list;
 406         struct bpf_lru_node *node = NULL;
 407         struct bpf_lru_list *l;
 408         unsigned long flags;
 409         int cpu = raw_smp_processor_id();
 410
 411         l = per_cpu_ptr(lru->percpu_lru, cpu);
 412
 413         raw_spin_lock_irqsave(&l->lock, flags);
 414
 415         __bpf_lru_list_rotate(lru, l);
 416
 417         free_list = &l->lists[BPF_LRU_LIST_T_FREE];
 418         if (list_empty(free_list))
 419                 __bpf_lru_list_shrink(lru, l, PERCPU_FREE_TARGET, free_list,
 420                                       BPF_LRU_LIST_T_FREE);
 421
 422         if (!list_empty(free_list)) {
 423                 node = list_first_entry(free_list, struct bpf_lru_node, list);
 424                 *(u32 *)((void *)node + lru->hash_offset) = hash;
 425                 node->ref = 0;
 426                 __bpf_lru_node_move(l, node, BPF_LRU_LIST_T_INACTIVE);
 427         }
 428
 429         raw_spin_unlock_irqrestore(&l->lock, flags);
 430
 431         return node;
 432 }
 433
 434 static struct bpf_lru_node *bpf_common_lru_pop_free(struct bpf_lru *lru,
 435                                                     u32 hash)
 436 {
 437         struct bpf_lru_locallist *loc_l, *steal_loc_l;
 438         struct bpf_common_lru *clru = &lru->common_lru;
 439         struct bpf_lru_node *node;
 440         int steal, first_steal;
 441         unsigned long flags;
 442         int cpu = raw_smp_processor_id();
 443
 444         loc_l = per_cpu_ptr(clru->local_list, cpu);
 445
 446         raw_spin_lock_irqsave(&loc_l->lock, flags);
 447
 448         node = __local_list_pop_free(loc_l);
 449         if (!node) {
 450                 bpf_lru_list_pop_free_to_local(lru, loc_l);
 451                 node = __local_list_pop_free(loc_l);
 452         }
 453
 454         if (node)
 455                 __local_list_add_pending(lru, loc_l, cpu, node, hash);
 456
 457         raw_spin_unlock_irqrestore(&loc_l->lock, flags);
 458
 459         if (node)
 460                 return node;
 461
 462         /* No free nodes found from the local free list and
 463          * the global LRU list.
 464          *
 465          * Steal from the local free/pending list of the
 466          * current CPU and remote CPU in RR.  It starts
 467          * with the loc_l->next_steal CPU.
 468          */
 469
 470         first_steal = loc_l->next_steal;
 471         steal = first_steal;
 472         do {
 473                 steal_loc_l = per_cpu_ptr(clru->local_list, steal);
 474
 475                 raw_spin_lock_irqsave(&steal_loc_l->lock, flags);
 476
 477                 node = __local_list_pop_free(steal_loc_l);
 478                 if (!node)
 479                         node = __local_list_pop_pending(lru, steal_loc_l);
 480
 481                 raw_spin_unlock_irqrestore(&steal_loc_l->lock, flags);
 482
 483                 steal = get_next_cpu(steal);
 484         } while (!node && steal != first_steal);
 485
 486         loc_l->next_steal = steal;
 487
 488         if (node) {
 489                 raw_spin_lock_irqsave(&loc_l->lock, flags);
 490                 __local_list_add_pending(lru, loc_l, cpu, node, hash);
 491                 raw_spin_unlock_irqrestore(&loc_l->lock, flags);
 492         }
 493
 494         return node;
 495 }
 496
 497 struct bpf_lru_node *bpf_lru_pop_free(struct bpf_lru *lru, u32 hash)
 498 {
 499         if (lru->percpu)
 500                 return bpf_percpu_lru_pop_free(lru, hash);
 501         else
 502                 return bpf_common_lru_pop_free(lru, hash);
 503 }
 504
 505 static void bpf_common_lru_push_free(struct bpf_lru *lru,
 506                                      struct bpf_lru_node *node)
 507 {
 508         unsigned long flags;
 509
 510         if (WARN_ON_ONCE(node->type == BPF_LRU_LIST_T_FREE) ||
 511             WARN_ON_ONCE(node->type == BPF_LRU_LOCAL_LIST_T_FREE))
 512                 return;
 513
 514         if (node->type == BPF_LRU_LOCAL_LIST_T_PENDING) {
 515                 struct bpf_lru_locallist *loc_l;
 516
 517                 loc_l = per_cpu_ptr(lru->common_lru.local_list, node->cpu);
 518
 519                 raw_spin_lock_irqsave(&loc_l->lock, flags);
 520
 521                 if (unlikely(node->type != BPF_LRU_LOCAL_LIST_T_PENDING)) {
 522                         raw_spin_unlock_irqrestore(&loc_l->lock, flags);
 523                         goto check_lru_list;
 524                 }
 525
 526                 node->type = BPF_LRU_LOCAL_LIST_T_FREE;
 527                 node->ref = 0;
 528                 list_move(&node->list, local_free_list(loc_l));
 529
 530                 raw_spin_unlock_irqrestore(&loc_l->lock, flags);
 531                 return;
 532         }
 533
 534 check_lru_list:
 535         bpf_lru_list_push_free(&lru->common_lru.lru_list, node);
 536 }
 537
 538 static void bpf_percpu_lru_push_free(struct bpf_lru *lru,
 539                                      struct bpf_lru_node *node)
 540 {
 541         struct bpf_lru_list *l;
 542         unsigned long flags;
 543
 544         l = per_cpu_ptr(lru->percpu_lru, node->cpu);
 545
 546         raw_spin_lock_irqsave(&l->lock, flags);
 547
 548         __bpf_lru_node_move(l, node, BPF_LRU_LIST_T_FREE);
 549
 550         raw_spin_unlock_irqrestore(&l->lock, flags);
 551 }
 552
 553 void bpf_lru_push_free(struct bpf_lru *lru, struct bpf_lru_node *node)
 554 {
 555         if (lru->percpu)
 556                 bpf_percpu_lru_push_free(lru, node);
 557         else
 558                 bpf_common_lru_push_free(lru, node);
 559 }
 560
 561 static void bpf_common_lru_populate(struct bpf_lru *lru, void *buf,
 562                                     u32 node_offset, u32 elem_size,
 563                                     u32 nr_elems)
 564 {
 565         struct bpf_lru_list *l = &lru->common_lru.lru_list;
 566         u32 i;
 567
 568         for (i = 0; i < nr_elems; i++) {
 569                 struct bpf_lru_node *node;
 570
 571                 node = (struct bpf_lru_node *)(buf + node_offset);
 572                 node->type = BPF_LRU_LIST_T_FREE;
 573                 node->ref = 0;
 574                 list_add(&node->list, &l->lists[BPF_LRU_LIST_T_FREE]);
 575                 buf += elem_size;
 576         }
 577 }
 578
 579 static void bpf_percpu_lru_populate(struct bpf_lru *lru, void *buf,
 580                                     u32 node_offset, u32 elem_size,
 581                                     u32 nr_elems)
 582 {
 583         u32 i, pcpu_entries;
 584         int cpu;
 585         struct bpf_lru_list *l;
 586
 587         pcpu_entries = nr_elems / num_possible_cpus();
 588
 589         i = 0;
 590
 591         for_each_possible_cpu(cpu) {
 592                 struct bpf_lru_node *node;
 593
 594                 l = per_cpu_ptr(lru->percpu_lru, cpu);
 595 again:
 596                 node = (struct bpf_lru_node *)(buf + node_offset);
 597                 node->cpu = cpu;
 598                 node->type = BPF_LRU_LIST_T_FREE;
 599                 node->ref = 0;
 600                 list_add(&node->list, &l->lists[BPF_LRU_LIST_T_FREE]);
 601                 i++;
 602                 buf += elem_size;
 603                 if (i == nr_elems)
 604                         break;
 605                 if (i % pcpu_entries)
 606                         goto again;
 607         }
 608 }
 609
 610 void bpf_lru_populate(struct bpf_lru *lru, void *buf, u32 node_offset,
 611                       u32 elem_size, u32 nr_elems)
 612 {
 613         if (lru->percpu)
 614                 bpf_percpu_lru_populate(lru, buf, node_offset, elem_size,
 615                                         nr_elems);
 616         else
 617                 bpf_common_lru_populate(lru, buf, node_offset, elem_size,
 618                                         nr_elems);
 619 }
 620
 621 static void bpf_lru_locallist_init(struct bpf_lru_locallist *loc_l, int cpu)
 622 {
 623         int i;
 624
 625         for (i = 0; i < NR_BPF_LRU_LOCAL_LIST_T; i++)
 626                 INIT_LIST_HEAD(&loc_l->lists[i]);
 627
 628         loc_l->next_steal = cpu;
 629
 630         raw_spin_lock_init(&loc_l->lock);
 631 }
 632
 633 static void bpf_lru_list_init(struct bpf_lru_list *l)
 634 {
 635         int i;
 636
 637         for (i = 0; i < NR_BPF_LRU_LIST_T; i++)
 638                 INIT_LIST_HEAD(&l->lists[i]);
 639
 640         for (i = 0; i < NR_BPF_LRU_LIST_COUNT; i++)
 641                 l->counts[i] = 0;
 642
 643         l->next_inactive_rotation = &l->lists[BPF_LRU_LIST_T_INACTIVE];
 644
 645         raw_spin_lock_init(&l->lock);
 646 }
 647
 648 int bpf_lru_init(struct bpf_lru *lru, bool percpu, u32 hash_offset,
 649                  del_from_htab_func del_from_htab, void *del_arg)
 650 {
 651         int cpu;
 652
 653         if (percpu) {
 654                 lru->percpu_lru = alloc_percpu(struct bpf_lru_list);
 655                 if (!lru->percpu_lru)
 656                         return -ENOMEM;
 657
 658                 for_each_possible_cpu(cpu) {
 659                         struct bpf_lru_list *l;
 660
 661                         l = per_cpu_ptr(lru->percpu_lru, cpu);
 662                         bpf_lru_list_init(l);
 663                 }
 664                 lru->nr_scans = PERCPU_NR_SCANS;
 665         } else {
 666                 struct bpf_common_lru *clru = &lru->common_lru;
 667
 668                 clru->local_list = alloc_percpu(struct bpf_lru_locallist);
 669                 if (!clru->local_list)
 670                         return -ENOMEM;
 671
 672                 for_each_possible_cpu(cpu) {
 673                         struct bpf_lru_locallist *loc_l;
 674
 675                         loc_l = per_cpu_ptr(clru->local_list, cpu);
 676                         bpf_lru_locallist_init(loc_l, cpu);
 677                 }
 678
 679                 bpf_lru_list_init(&clru->lru_list);
 680                 lru->nr_scans = LOCAL_NR_SCANS;
 681         }
 682
 683         lru->percpu = percpu;
 684         lru->del_from_htab = del_from_htab;
 685         lru->del_arg = del_arg;
 686         lru->hash_offset = hash_offset;
 687
 688         return 0;
 689 }
 690
 691 void bpf_lru_destroy(struct bpf_lru *lru)
 692 {
 693         if (lru->percpu)
 694                 free_percpu(lru->percpu_lru);
 695         else
 696                 free_percpu(lru->common_lru.local_list);
 697 }