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         /*
  46          * This needs node 0 to be always present, even
  47          * in the systems supporting sparse numa ids.
  48          */
  49         return !!lru->node[0].memcg_lrus;
  50 }
  51
  52 static inline struct list_lru_one *
  53 list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
  54 {
  55         /*
  56          * The lock protects the array of per cgroup lists from relocation
  57          * (see memcg_update_list_lru_node).
  58          */
  59         lockdep_assert_held(&nlru->lock);
  60         if (nlru->memcg_lrus && idx >= 0)
  61                 return nlru->memcg_lrus->lru[idx];
  62
  63         return &nlru->lru;
  64 }
  65
  66 static __always_inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr)
  67 {
  68         struct page *page;
  69
  70         if (!memcg_kmem_enabled())
  71                 return NULL;
  72         page = virt_to_head_page(ptr);
  73         return page->mem_cgroup;
  74 }
  75
  76 static inline struct list_lru_one *
  77 list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
  78 {
  79         struct mem_cgroup *memcg;
  80
  81         if (!nlru->memcg_lrus)
  82                 return &nlru->lru;
  83
  84         memcg = mem_cgroup_from_kmem(ptr);
  85         if (!memcg)
  86                 return &nlru->lru;
  87
  88         return list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
  89 }
  90 #else
  91 static inline bool list_lru_memcg_aware(struct list_lru *lru)
  92 {
  93         return false;
  94 }
  95
  96 static inline struct list_lru_one *
  97 list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
  98 {
  99         return &nlru->lru;
 100 }
 101
 102 static inline struct list_lru_one *
 103 list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
 104 {
 105         return &nlru->lru;
 106 }
 107 #endif /* CONFIG_MEMCG_KMEM */
 108
 109 bool list_lru_add(struct list_lru *lru, struct list_head *item)
 110 {
 111         int nid = page_to_nid(virt_to_page(item));
 112         struct list_lru_node *nlru = &lru->node[nid];
 113         struct list_lru_one *l;
 114
 115         spin_lock(&nlru->lock);
 116         if (list_empty(item)) {
 117                 l = list_lru_from_kmem(nlru, item);
 118                 list_add_tail(item, &l->list);
 119                 l->nr_items++;
 120                 nlru->nr_items++;
 121                 spin_unlock(&nlru->lock);
 122                 return true;
 123         }
 124         spin_unlock(&nlru->lock);
 125         return false;
 126 }
 127 EXPORT_SYMBOL_GPL(list_lru_add);
 128
 129 bool list_lru_del(struct list_lru *lru, struct list_head *item)
 130 {
 131         int nid = page_to_nid(virt_to_page(item));
 132         struct list_lru_node *nlru = &lru->node[nid];
 133         struct list_lru_one *l;
 134
 135         spin_lock(&nlru->lock);
 136         if (!list_empty(item)) {
 137                 l = list_lru_from_kmem(nlru, item);
 138                 list_del_init(item);
 139                 l->nr_items--;
 140                 nlru->nr_items--;
 141                 spin_unlock(&nlru->lock);
 142                 return true;
 143         }
 144         spin_unlock(&nlru->lock);
 145         return false;
 146 }
 147 EXPORT_SYMBOL_GPL(list_lru_del);
 148
 149 void list_lru_isolate(struct list_lru_one *list, struct list_head *item)
 150 {
 151         list_del_init(item);
 152         list->nr_items--;
 153 }
 154 EXPORT_SYMBOL_GPL(list_lru_isolate);
 155
 156 void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item,
 157                            struct list_head *head)
 158 {
 159         list_move(item, head);
 160         list->nr_items--;
 161 }
 162 EXPORT_SYMBOL_GPL(list_lru_isolate_move);
 163
 164 static unsigned long __list_lru_count_one(struct list_lru *lru,
 165                                           int nid, int memcg_idx)
 166 {
 167         struct list_lru_node *nlru = &lru->node[nid];
 168         struct list_lru_one *l;
 169         unsigned long count;
 170
 171         spin_lock(&nlru->lock);
 172         l = list_lru_from_memcg_idx(nlru, memcg_idx);
 173         count = l->nr_items;
 174         spin_unlock(&nlru->lock);
 175
 176         return count;
 177 }
 178
 179 unsigned long list_lru_count_one(struct list_lru *lru,
 180                                  int nid, struct mem_cgroup *memcg)
 181 {
 182         return __list_lru_count_one(lru, nid, memcg_cache_id(memcg));
 183 }
 184 EXPORT_SYMBOL_GPL(list_lru_count_one);
 185
 186 unsigned long list_lru_count_node(struct list_lru *lru, int nid)
 187 {
 188         struct list_lru_node *nlru;
 189
 190         nlru = &lru->node[nid];
 191         return nlru->nr_items;
 192 }
 193 EXPORT_SYMBOL_GPL(list_lru_count_node);
 194
 195 static unsigned long
 196 __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx,
 197                     list_lru_walk_cb isolate, void *cb_arg,
 198                     unsigned long *nr_to_walk)
 199 {
 200
 201         struct list_lru_node *nlru = &lru->node[nid];
 202         struct list_lru_one *l;
 203         struct list_head *item, *n;
 204         unsigned long isolated = 0;
 205
 206         spin_lock(&nlru->lock);
 207         l = list_lru_from_memcg_idx(nlru, memcg_idx);
 208 restart:
 209         list_for_each_safe(item, n, &l->list) {
 210                 enum lru_status ret;
 211
 212                 /*
 213                  * decrement nr_to_walk first so that we don't livelock if we
 214                  * get stuck on large numbesr of LRU_RETRY items
 215                  */
 216                 if (!*nr_to_walk)
 217                         break;
 218                 --*nr_to_walk;
 219
 220                 ret = isolate(item, l, &nlru->lock, cb_arg);
 221                 switch (ret) {
 222                 case LRU_REMOVED_RETRY:
 223                         assert_spin_locked(&nlru->lock);
 224                 case LRU_REMOVED:
 225                         isolated++;
 226                         nlru->nr_items--;
 227                         /*
 228                          * If the lru lock has been dropped, our list
 229                          * traversal is now invalid and so we have to
 230                          * restart from scratch.
 231                          */
 232                         if (ret == LRU_REMOVED_RETRY)
 233                                 goto restart;
 234                         break;
 235                 case LRU_ROTATE:
 236                         list_move_tail(item, &l->list);
 237                         break;
 238                 case LRU_SKIP:
 239                         break;
 240                 case LRU_RETRY:
 241                         /*
 242                          * The lru lock has been dropped, our list traversal is
 243                          * now invalid and so we have to restart from scratch.
 244                          */
 245                         assert_spin_locked(&nlru->lock);
 246                         goto restart;
 247                 default:
 248                         BUG();
 249                 }
 250         }
 251
 252         spin_unlock(&nlru->lock);
 253         return isolated;
 254 }
 255
 256 unsigned long
 257 list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
 258                   list_lru_walk_cb isolate, void *cb_arg,
 259                   unsigned long *nr_to_walk)
 260 {
 261         return __list_lru_walk_one(lru, nid, memcg_cache_id(memcg),
 262                                    isolate, cb_arg, nr_to_walk);
 263 }
 264 EXPORT_SYMBOL_GPL(list_lru_walk_one);
 265
 266 unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
 267                                  list_lru_walk_cb isolate, void *cb_arg,
 268                                  unsigned long *nr_to_walk)
 269 {
 270         long isolated = 0;
 271         int memcg_idx;
 272
 273         isolated += __list_lru_walk_one(lru, nid, -1, isolate, cb_arg,
 274                                         nr_to_walk);
 275         if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) {
 276                 for_each_memcg_cache_index(memcg_idx) {
 277                         isolated += __list_lru_walk_one(lru, nid, memcg_idx,
 278                                                 isolate, cb_arg, nr_to_walk);
 279                         if (*nr_to_walk <= 0)
 280                                 break;
 281                 }
 282         }
 283         return isolated;
 284 }
 285 EXPORT_SYMBOL_GPL(list_lru_walk_node);
 286
 287 static void init_one_lru(struct list_lru_one *l)
 288 {
 289         INIT_LIST_HEAD(&l->list);
 290         l->nr_items = 0;
 291 }
 292
 293 #ifdef CONFIG_MEMCG_KMEM
 294 static void __memcg_destroy_list_lru_node(struct list_lru_memcg *memcg_lrus,
 295                                           int begin, int end)
 296 {
 297         int i;
 298
 299         for (i = begin; i < end; i++)
 300                 kfree(memcg_lrus->lru[i]);
 301 }
 302
 303 static int __memcg_init_list_lru_node(struct list_lru_memcg *memcg_lrus,
 304                                       int begin, int end)
 305 {
 306         int i;
 307
 308         for (i = begin; i < end; i++) {
 309                 struct list_lru_one *l;
 310
 311                 l = kmalloc(sizeof(struct list_lru_one), GFP_KERNEL);
 312                 if (!l)
 313                         goto fail;
 314
 315                 init_one_lru(l);
 316                 memcg_lrus->lru[i] = l;
 317         }
 318         return 0;
 319 fail:
 320         __memcg_destroy_list_lru_node(memcg_lrus, begin, i - 1);
 321         return -ENOMEM;
 322 }
 323
 324 static int memcg_init_list_lru_node(struct list_lru_node *nlru)
 325 {
 326         int size = memcg_nr_cache_ids;
 327
 328         nlru->memcg_lrus = kmalloc(size * sizeof(void *), GFP_KERNEL);
 329         if (!nlru->memcg_lrus)
 330                 return -ENOMEM;
 331
 332         if (__memcg_init_list_lru_node(nlru->memcg_lrus, 0, size)) {
 333                 kfree(nlru->memcg_lrus);
 334                 return -ENOMEM;
 335         }
 336
 337         return 0;
 338 }
 339
 340 static void memcg_destroy_list_lru_node(struct list_lru_node *nlru)
 341 {
 342         __memcg_destroy_list_lru_node(nlru->memcg_lrus, 0, memcg_nr_cache_ids);
 343         kfree(nlru->memcg_lrus);
 344 }
 345
 346 static int memcg_update_list_lru_node(struct list_lru_node *nlru,
 347                                       int old_size, int new_size)
 348 {
 349         struct list_lru_memcg *old, *new;
 350
 351         BUG_ON(old_size > new_size);
 352
 353         old = nlru->memcg_lrus;
 354         new = kmalloc(new_size * sizeof(void *), GFP_KERNEL);
 355         if (!new)
 356                 return -ENOMEM;
 357
 358         if (__memcg_init_list_lru_node(new, old_size, new_size)) {
 359                 kfree(new);
 360                 return -ENOMEM;
 361         }
 362
 363         memcpy(new, old, old_size * sizeof(void *));
 364
 365         /*
 366          * The lock guarantees that we won't race with a reader
 367          * (see list_lru_from_memcg_idx).
 368          *
 369          * Since list_lru_{add,del} may be called under an IRQ-safe lock,
 370          * we have to use IRQ-safe primitives here to avoid deadlock.
 371          */
 372         spin_lock_irq(&nlru->lock);
 373         nlru->memcg_lrus = new;
 374         spin_unlock_irq(&nlru->lock);
 375
 376         kfree(old);
 377         return 0;
 378 }
 379
 380 static void memcg_cancel_update_list_lru_node(struct list_lru_node *nlru,
 381                                               int old_size, int new_size)
 382 {
 383         /* do not bother shrinking the array back to the old size, because we
 384          * cannot handle allocation failures here */
 385         __memcg_destroy_list_lru_node(nlru->memcg_lrus, old_size, new_size);
 386 }
 387
 388 static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 389 {
 390         int i;
 391
 392         if (!memcg_aware)
 393                 return 0;
 394
 395         for_each_node(i) {
 396                 if (memcg_init_list_lru_node(&lru->node[i]))
 397                         goto fail;
 398         }
 399         return 0;
 400 fail:
 401         for (i = i - 1; i >= 0; i--) {
 402                 if (!lru->node[i].memcg_lrus)
 403                         continue;
 404                 memcg_destroy_list_lru_node(&lru->node[i]);
 405         }
 406         return -ENOMEM;
 407 }
 408
 409 static void memcg_destroy_list_lru(struct list_lru *lru)
 410 {
 411         int i;
 412
 413         if (!list_lru_memcg_aware(lru))
 414                 return;
 415
 416         for_each_node(i)
 417                 memcg_destroy_list_lru_node(&lru->node[i]);
 418 }
 419
 420 static int memcg_update_list_lru(struct list_lru *lru,
 421                                  int old_size, int new_size)
 422 {
 423         int i;
 424
 425         if (!list_lru_memcg_aware(lru))
 426                 return 0;
 427
 428         for_each_node(i) {
 429                 if (memcg_update_list_lru_node(&lru->node[i],
 430                                                old_size, new_size))
 431                         goto fail;
 432         }
 433         return 0;
 434 fail:
 435         for (i = i - 1; i >= 0; i--) {
 436                 if (!lru->node[i].memcg_lrus)
 437                         continue;
 438
 439                 memcg_cancel_update_list_lru_node(&lru->node[i],
 440                                                   old_size, new_size);
 441         }
 442         return -ENOMEM;
 443 }
 444
 445 static void memcg_cancel_update_list_lru(struct list_lru *lru,
 446                                          int old_size, int new_size)
 447 {
 448         int i;
 449
 450         if (!list_lru_memcg_aware(lru))
 451                 return;
 452
 453         for_each_node(i)
 454                 memcg_cancel_update_list_lru_node(&lru->node[i],
 455                                                   old_size, new_size);
 456 }
 457
 458 int memcg_update_all_list_lrus(int new_size)
 459 {
 460         int ret = 0;
 461         struct list_lru *lru;
 462         int old_size = memcg_nr_cache_ids;
 463
 464         mutex_lock(&list_lrus_mutex);
 465         list_for_each_entry(lru, &list_lrus, list) {
 466                 ret = memcg_update_list_lru(lru, old_size, new_size);
 467                 if (ret)
 468                         goto fail;
 469         }
 470 out:
 471         mutex_unlock(&list_lrus_mutex);
 472         return ret;
 473 fail:
 474         list_for_each_entry_continue_reverse(lru, &list_lrus, list)
 475                 memcg_cancel_update_list_lru(lru, old_size, new_size);
 476         goto out;
 477 }
 478
 479 static void memcg_drain_list_lru_node(struct list_lru_node *nlru,
 480                                       int src_idx, int dst_idx)
 481 {
 482         struct list_lru_one *src, *dst;
 483
 484         /*
 485          * Since list_lru_{add,del} may be called under an IRQ-safe lock,
 486          * we have to use IRQ-safe primitives here to avoid deadlock.
 487          */
 488         spin_lock_irq(&nlru->lock);
 489
 490         src = list_lru_from_memcg_idx(nlru, src_idx);
 491         dst = list_lru_from_memcg_idx(nlru, dst_idx);
 492
 493         list_splice_init(&src->list, &dst->list);
 494         dst->nr_items += src->nr_items;
 495         src->nr_items = 0;
 496
 497         spin_unlock_irq(&nlru->lock);
 498 }
 499
 500 static void memcg_drain_list_lru(struct list_lru *lru,
 501                                  int src_idx, int dst_idx)
 502 {
 503         int i;
 504
 505         if (!list_lru_memcg_aware(lru))
 506                 return;
 507
 508         for_each_node(i)
 509                 memcg_drain_list_lru_node(&lru->node[i], src_idx, dst_idx);
 510 }
 511
 512 void memcg_drain_all_list_lrus(int src_idx, int dst_idx)
 513 {
 514         struct list_lru *lru;
 515
 516         mutex_lock(&list_lrus_mutex);
 517         list_for_each_entry(lru, &list_lrus, list)
 518                 memcg_drain_list_lru(lru, src_idx, dst_idx);
 519         mutex_unlock(&list_lrus_mutex);
 520 }
 521 #else
 522 static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 523 {
 524         return 0;
 525 }
 526
 527 static void memcg_destroy_list_lru(struct list_lru *lru)
 528 {
 529 }
 530 #endif /* CONFIG_MEMCG_KMEM */
 531
 532 int __list_lru_init(struct list_lru *lru, bool memcg_aware,
 533                     struct lock_class_key *key)
 534 {
 535         int i;
 536         size_t size = sizeof(*lru->node) * nr_node_ids;
 537         int err = -ENOMEM;
 538
 539         memcg_get_cache_ids();
 540
 541         lru->node = kzalloc(size, GFP_KERNEL);
 542         if (!lru->node)
 543                 goto out;
 544
 545         for_each_node(i) {
 546                 spin_lock_init(&lru->node[i].lock);
 547                 if (key)
 548                         lockdep_set_class(&lru->node[i].lock, key);
 549                 init_one_lru(&lru->node[i].lru);
 550         }
 551
 552         err = memcg_init_list_lru(lru, memcg_aware);
 553         if (err) {
 554                 kfree(lru->node);
 555                 /* Do this so a list_lru_destroy() doesn't crash: */
 556                 lru->node = NULL;
 557                 goto out;
 558         }
 559
 560         list_lru_register(lru);
 561 out:
 562         memcg_put_cache_ids();
 563         return err;
 564 }
 565 EXPORT_SYMBOL_GPL(__list_lru_init);
 566
 567 void list_lru_destroy(struct list_lru *lru)
 568 {
 569         /* Already destroyed or not yet initialized? */
 570         if (!lru->node)
 571                 return;
 572
 573         memcg_get_cache_ids();
 574
 575         list_lru_unregister(lru);
 576
 577         memcg_destroy_list_lru(lru);
 578         kfree(lru->node);
 579         lru->node = NULL;
 580
 581         memcg_put_cache_ids();
 582 }
 583 EXPORT_SYMBOL_GPL(list_lru_destroy);