mm/list_lru.c

   1 /*
   2  * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved.
   3  * Authors: David Chinner and Glauber Costa
   4  *
   5  * Generic LRU infrastructure
   6  */
   7 #include <linux/kernel.h>
   8 #include <linux/module.h>
   9 #include <linux/mm.h>
  10 #include <linux/list_lru.h>
  11 #include <linux/slab.h>
  12 #include <linux/mutex.h>
  13 #include <linux/memcontrol.h>
  14
  15 #ifdef CONFIG_MEMCG_KMEM
  16 static LIST_HEAD(list_lrus);
  17 static DEFINE_MUTEX(list_lrus_mutex);
  18
  19 static void list_lru_register(struct list_lru *lru)
  20 {
  21         mutex_lock(&list_lrus_mutex);
  22         list_add(&lru->list, &list_lrus);
  23         mutex_unlock(&list_lrus_mutex);
  24 }
  25
  26 static void list_lru_unregister(struct list_lru *lru)
  27 {
  28         mutex_lock(&list_lrus_mutex);
  29         list_del(&lru->list);
  30         mutex_unlock(&list_lrus_mutex);
  31 }
  32 #else
  33 static void list_lru_register(struct list_lru *lru)
  34 {
  35 }
  36
  37 static void list_lru_unregister(struct list_lru *lru)
  38 {
  39 }
  40 #endif /* CONFIG_MEMCG_KMEM */
  41
  42 #ifdef CONFIG_MEMCG_KMEM
  43 static inline bool list_lru_memcg_aware(struct list_lru *lru)
  44 {
  45         return !!lru->node[0].memcg_lrus;
  46 }
  47
  48 static inline struct list_lru_one *
  49 list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
  50 {
  51         /*
  52          * The lock protects the array of per cgroup lists from relocation
  53          * (see memcg_update_list_lru_node).
  54          */
  55         lockdep_assert_held(&nlru->lock);
  56         if (nlru->memcg_lrus && idx >= 0)
  57                 return nlru->memcg_lrus->lru[idx];
  58
  59         return &nlru->lru;
  60 }
  61
  62 static inline struct list_lru_one *
  63 list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
  64 {
  65         struct mem_cgroup *memcg;
  66
  67         if (!nlru->memcg_lrus)
  68                 return &nlru->lru;
  69
  70         memcg = mem_cgroup_from_kmem(ptr);
  71         if (!memcg)
  72                 return &nlru->lru;
  73
  74         return list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
  75 }
  76 #else
  77 static inline bool list_lru_memcg_aware(struct list_lru *lru)
  78 {
  79         return false;
  80 }
  81
  82 static inline struct list_lru_one *
  83 list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
  84 {
  85         return &nlru->lru;
  86 }
  87
  88 static inline struct list_lru_one *
  89 list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
  90 {
  91         return &nlru->lru;
  92 }
  93 #endif /* CONFIG_MEMCG_KMEM */
  94
  95 bool list_lru_add(struct list_lru *lru, struct list_head *item)
  96 {
  97         int nid = page_to_nid(virt_to_page(item));
  98         struct list_lru_node *nlru = &lru->node[nid];
  99         struct list_lru_one *l;
 100
 101         spin_lock(&nlru->lock);
 102         l = list_lru_from_kmem(nlru, item);
 103         if (list_empty(item)) {
 104                 list_add_tail(item, &l->list);
 105                 l->nr_items++;
 106                 spin_unlock(&nlru->lock);
 107                 return true;
 108         }
 109         spin_unlock(&nlru->lock);
 110         return false;
 111 }
 112 EXPORT_SYMBOL_GPL(list_lru_add);
 113
 114 bool list_lru_del(struct list_lru *lru, struct list_head *item)
 115 {
 116         int nid = page_to_nid(virt_to_page(item));
 117         struct list_lru_node *nlru = &lru->node[nid];
 118         struct list_lru_one *l;
 119
 120         spin_lock(&nlru->lock);
 121         l = list_lru_from_kmem(nlru, item);
 122         if (!list_empty(item)) {
 123                 list_del_init(item);
 124                 l->nr_items--;
 125                 spin_unlock(&nlru->lock);
 126                 return true;
 127         }
 128         spin_unlock(&nlru->lock);
 129         return false;
 130 }
 131 EXPORT_SYMBOL_GPL(list_lru_del);
 132
 133 void list_lru_isolate(struct list_lru_one *list, struct list_head *item)
 134 {
 135         list_del_init(item);
 136         list->nr_items--;
 137 }
 138 EXPORT_SYMBOL_GPL(list_lru_isolate);
 139
 140 void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item,
 141                            struct list_head *head)
 142 {
 143         list_move(item, head);
 144         list->nr_items--;
 145 }
 146 EXPORT_SYMBOL_GPL(list_lru_isolate_move);
 147
 148 static unsigned long __list_lru_count_one(struct list_lru *lru,
 149                                           int nid, int memcg_idx)
 150 {
 151         struct list_lru_node *nlru = &lru->node[nid];
 152         struct list_lru_one *l;
 153         unsigned long count;
 154
 155         spin_lock(&nlru->lock);
 156         l = list_lru_from_memcg_idx(nlru, memcg_idx);
 157         count = l->nr_items;
 158         spin_unlock(&nlru->lock);
 159
 160         return count;
 161 }
 162
 163 unsigned long list_lru_count_one(struct list_lru *lru,
 164                                  int nid, struct mem_cgroup *memcg)
 165 {
 166         return __list_lru_count_one(lru, nid, memcg_cache_id(memcg));
 167 }
 168 EXPORT_SYMBOL_GPL(list_lru_count_one);
 169
 170 unsigned long list_lru_count_node(struct list_lru *lru, int nid)
 171 {
 172         long count = 0;
 173         int memcg_idx;
 174
 175         count += __list_lru_count_one(lru, nid, -1);
 176         if (list_lru_memcg_aware(lru)) {
 177                 for_each_memcg_cache_index(memcg_idx)
 178                         count += __list_lru_count_one(lru, nid, memcg_idx);
 179         }
 180         return count;
 181 }
 182 EXPORT_SYMBOL_GPL(list_lru_count_node);
 183
 184 static unsigned long
 185 __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx,
 186                     list_lru_walk_cb isolate, void *cb_arg,
 187                     unsigned long *nr_to_walk)
 188 {
 189
 190         struct list_lru_node *nlru = &lru->node[nid];
 191         struct list_lru_one *l;
 192         struct list_head *item, *n;
 193         unsigned long isolated = 0;
 194
 195         spin_lock(&nlru->lock);
 196         l = list_lru_from_memcg_idx(nlru, memcg_idx);
 197 restart:
 198         list_for_each_safe(item, n, &l->list) {
 199                 enum lru_status ret;
 200
 201                 /*
 202                  * decrement nr_to_walk first so that we don't livelock if we
 203                  * get stuck on large numbesr of LRU_RETRY items
 204                  */
 205                 if (!*nr_to_walk)
 206                         break;
 207                 --*nr_to_walk;
 208
 209                 ret = isolate(item, l, &nlru->lock, cb_arg);
 210                 switch (ret) {
 211                 case LRU_REMOVED_RETRY:
 212                         assert_spin_locked(&nlru->lock);
 213                 case LRU_REMOVED:
 214                         isolated++;
 215                         /*
 216                          * If the lru lock has been dropped, our list
 217                          * traversal is now invalid and so we have to
 218                          * restart from scratch.
 219                          */
 220                         if (ret == LRU_REMOVED_RETRY)
 221                                 goto restart;
 222                         break;
 223                 case LRU_ROTATE:
 224                         list_move_tail(item, &l->list);
 225                         break;
 226                 case LRU_SKIP:
 227                         break;
 228                 case LRU_RETRY:
 229                         /*
 230                          * The lru lock has been dropped, our list traversal is
 231                          * now invalid and so we have to restart from scratch.
 232                          */
 233                         assert_spin_locked(&nlru->lock);
 234                         goto restart;
 235                 default:
 236                         BUG();
 237                 }
 238         }
 239
 240         spin_unlock(&nlru->lock);
 241         return isolated;
 242 }
 243
 244 unsigned long
 245 list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
 246                   list_lru_walk_cb isolate, void *cb_arg,
 247                   unsigned long *nr_to_walk)
 248 {
 249         return __list_lru_walk_one(lru, nid, memcg_cache_id(memcg),
 250                                    isolate, cb_arg, nr_to_walk);
 251 }
 252 EXPORT_SYMBOL_GPL(list_lru_walk_one);
 253
 254 unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
 255                                  list_lru_walk_cb isolate, void *cb_arg,
 256                                  unsigned long *nr_to_walk)
 257 {
 258         long isolated = 0;
 259         int memcg_idx;
 260
 261         isolated += __list_lru_walk_one(lru, nid, -1, isolate, cb_arg,
 262                                         nr_to_walk);
 263         if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) {
 264                 for_each_memcg_cache_index(memcg_idx) {
 265                         isolated += __list_lru_walk_one(lru, nid, memcg_idx,
 266                                                 isolate, cb_arg, nr_to_walk);
 267                         if (*nr_to_walk <= 0)
 268                                 break;
 269                 }
 270         }
 271         return isolated;
 272 }
 273 EXPORT_SYMBOL_GPL(list_lru_walk_node);
 274
 275 static void init_one_lru(struct list_lru_one *l)
 276 {
 277         INIT_LIST_HEAD(&l->list);
 278         l->nr_items = 0;
 279 }
 280
 281 #ifdef CONFIG_MEMCG_KMEM
 282 static void __memcg_destroy_list_lru_node(struct list_lru_memcg *memcg_lrus,
 283                                           int begin, int end)
 284 {
 285         int i;
 286
 287         for (i = begin; i < end; i++)
 288                 kfree(memcg_lrus->lru[i]);
 289 }
 290
 291 static int __memcg_init_list_lru_node(struct list_lru_memcg *memcg_lrus,
 292                                       int begin, int end)
 293 {
 294         int i;
 295
 296         for (i = begin; i < end; i++) {
 297                 struct list_lru_one *l;
 298
 299                 l = kmalloc(sizeof(struct list_lru_one), GFP_KERNEL);
 300                 if (!l)
 301                         goto fail;
 302
 303                 init_one_lru(l);
 304                 memcg_lrus->lru[i] = l;
 305         }
 306         return 0;
 307 fail:
 308         __memcg_destroy_list_lru_node(memcg_lrus, begin, i - 1);
 309         return -ENOMEM;
 310 }
 311
 312 static int memcg_init_list_lru_node(struct list_lru_node *nlru)
 313 {
 314         int size = memcg_nr_cache_ids;
 315
 316         nlru->memcg_lrus = kmalloc(size * sizeof(void *), GFP_KERNEL);
 317         if (!nlru->memcg_lrus)
 318                 return -ENOMEM;
 319
 320         if (__memcg_init_list_lru_node(nlru->memcg_lrus, 0, size)) {
 321                 kfree(nlru->memcg_lrus);
 322                 return -ENOMEM;
 323         }
 324
 325         return 0;
 326 }
 327
 328 static void memcg_destroy_list_lru_node(struct list_lru_node *nlru)
 329 {
 330         __memcg_destroy_list_lru_node(nlru->memcg_lrus, 0, memcg_nr_cache_ids);
 331         kfree(nlru->memcg_lrus);
 332 }
 333
 334 static int memcg_update_list_lru_node(struct list_lru_node *nlru,
 335                                       int old_size, int new_size)
 336 {
 337         struct list_lru_memcg *old, *new;
 338
 339         BUG_ON(old_size > new_size);
 340
 341         old = nlru->memcg_lrus;
 342         new = kmalloc(new_size * sizeof(void *), GFP_KERNEL);
 343         if (!new)
 344                 return -ENOMEM;
 345
 346         if (__memcg_init_list_lru_node(new, old_size, new_size)) {
 347                 kfree(new);
 348                 return -ENOMEM;
 349         }
 350
 351         memcpy(new, old, old_size * sizeof(void *));
 352
 353         /*
 354          * The lock guarantees that we won't race with a reader
 355          * (see list_lru_from_memcg_idx).
 356          *
 357          * Since list_lru_{add,del} may be called under an IRQ-safe lock,
 358          * we have to use IRQ-safe primitives here to avoid deadlock.
 359          */
 360         spin_lock_irq(&nlru->lock);
 361         nlru->memcg_lrus = new;
 362         spin_unlock_irq(&nlru->lock);
 363
 364         kfree(old);
 365         return 0;
 366 }
 367
 368 static void memcg_cancel_update_list_lru_node(struct list_lru_node *nlru,
 369                                               int old_size, int new_size)
 370 {
 371         /* do not bother shrinking the array back to the old size, because we
 372          * cannot handle allocation failures here */
 373         __memcg_destroy_list_lru_node(nlru->memcg_lrus, old_size, new_size);
 374 }
 375
 376 static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 377 {
 378         int i;
 379
 380         for (i = 0; i < nr_node_ids; i++) {
 381                 if (!memcg_aware)
 382                         lru->node[i].memcg_lrus = NULL;
 383                 else if (memcg_init_list_lru_node(&lru->node[i]))
 384                         goto fail;
 385         }
 386         return 0;
 387 fail:
 388         for (i = i - 1; i >= 0; i--)
 389                 memcg_destroy_list_lru_node(&lru->node[i]);
 390         return -ENOMEM;
 391 }
 392
 393 static void memcg_destroy_list_lru(struct list_lru *lru)
 394 {
 395         int i;
 396
 397         if (!list_lru_memcg_aware(lru))
 398                 return;
 399
 400         for (i = 0; i < nr_node_ids; i++)
 401                 memcg_destroy_list_lru_node(&lru->node[i]);
 402 }
 403
 404 static int memcg_update_list_lru(struct list_lru *lru,
 405                                  int old_size, int new_size)
 406 {
 407         int i;
 408
 409         if (!list_lru_memcg_aware(lru))
 410                 return 0;
 411
 412         for (i = 0; i < nr_node_ids; i++) {
 413                 if (memcg_update_list_lru_node(&lru->node[i],
 414                                                old_size, new_size))
 415                         goto fail;
 416         }
 417         return 0;
 418 fail:
 419         for (i = i - 1; i >= 0; i--)
 420                 memcg_cancel_update_list_lru_node(&lru->node[i],
 421                                                   old_size, new_size);
 422         return -ENOMEM;
 423 }
 424
 425 static void memcg_cancel_update_list_lru(struct list_lru *lru,
 426                                          int old_size, int new_size)
 427 {
 428         int i;
 429
 430         if (!list_lru_memcg_aware(lru))
 431                 return;
 432
 433         for (i = 0; i < nr_node_ids; i++)
 434                 memcg_cancel_update_list_lru_node(&lru->node[i],
 435                                                   old_size, new_size);
 436 }
 437
 438 int memcg_update_all_list_lrus(int new_size)
 439 {
 440         int ret = 0;
 441         struct list_lru *lru;
 442         int old_size = memcg_nr_cache_ids;
 443
 444         mutex_lock(&list_lrus_mutex);
 445         list_for_each_entry(lru, &list_lrus, list) {
 446                 ret = memcg_update_list_lru(lru, old_size, new_size);
 447                 if (ret)
 448                         goto fail;
 449         }
 450 out:
 451         mutex_unlock(&list_lrus_mutex);
 452         return ret;
 453 fail:
 454         list_for_each_entry_continue_reverse(lru, &list_lrus, list)
 455                 memcg_cancel_update_list_lru(lru, old_size, new_size);
 456         goto out;
 457 }
 458
 459 static void memcg_drain_list_lru_node(struct list_lru_node *nlru,
 460                                       int src_idx, int dst_idx)
 461 {
 462         struct list_lru_one *src, *dst;
 463
 464         /*
 465          * Since list_lru_{add,del} may be called under an IRQ-safe lock,
 466          * we have to use IRQ-safe primitives here to avoid deadlock.
 467          */
 468         spin_lock_irq(&nlru->lock);
 469
 470         src = list_lru_from_memcg_idx(nlru, src_idx);
 471         dst = list_lru_from_memcg_idx(nlru, dst_idx);
 472
 473         list_splice_init(&src->list, &dst->list);
 474         dst->nr_items += src->nr_items;
 475         src->nr_items = 0;
 476
 477         spin_unlock_irq(&nlru->lock);
 478 }
 479
 480 static void memcg_drain_list_lru(struct list_lru *lru,
 481                                  int src_idx, int dst_idx)
 482 {
 483         int i;
 484
 485         if (!list_lru_memcg_aware(lru))
 486                 return;
 487
 488         for (i = 0; i < nr_node_ids; i++)
 489                 memcg_drain_list_lru_node(&lru->node[i], src_idx, dst_idx);
 490 }
 491
 492 void memcg_drain_all_list_lrus(int src_idx, int dst_idx)
 493 {
 494         struct list_lru *lru;
 495
 496         mutex_lock(&list_lrus_mutex);
 497         list_for_each_entry(lru, &list_lrus, list)
 498                 memcg_drain_list_lru(lru, src_idx, dst_idx);
 499         mutex_unlock(&list_lrus_mutex);
 500 }
 501 #else
 502 static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 503 {
 504         return 0;
 505 }
 506
 507 static void memcg_destroy_list_lru(struct list_lru *lru)
 508 {
 509 }
 510 #endif /* CONFIG_MEMCG_KMEM */
 511
 512 int __list_lru_init(struct list_lru *lru, bool memcg_aware,
 513                     struct lock_class_key *key)
 514 {
 515         int i;
 516         size_t size = sizeof(*lru->node) * nr_node_ids;
 517         int err = -ENOMEM;
 518
 519         memcg_get_cache_ids();
 520
 521         lru->node = kzalloc(size, GFP_KERNEL);
 522         if (!lru->node)
 523                 goto out;
 524
 525         for (i = 0; i < nr_node_ids; i++) {
 526                 spin_lock_init(&lru->node[i].lock);
 527                 if (key)
 528                         lockdep_set_class(&lru->node[i].lock, key);
 529                 init_one_lru(&lru->node[i].lru);
 530         }
 531
 532         err = memcg_init_list_lru(lru, memcg_aware);
 533         if (err) {
 534                 kfree(lru->node);
 535                 goto out;
 536         }
 537
 538         list_lru_register(lru);
 539 out:
 540         memcg_put_cache_ids();
 541         return err;
 542 }
 543 EXPORT_SYMBOL_GPL(__list_lru_init);
 544
 545 void list_lru_destroy(struct list_lru *lru)
 546 {
 547         /* Already destroyed or not yet initialized? */
 548         if (!lru->node)
 549                 return;
 550
 551         memcg_get_cache_ids();
 552
 553         list_lru_unregister(lru);
 554
 555         memcg_destroy_list_lru(lru);
 556         kfree(lru->node);
 557         lru->node = NULL;
 558
 559         memcg_put_cache_ids();
 560 }
 561 EXPORT_SYMBOL_GPL(list_lru_destroy);