mm/slab.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef MM_SLAB_H
   3 #define MM_SLAB_H
   4 /*
   5  * Internal slab definitions
   6  */
   7
   8 #ifdef CONFIG_SLOB
   9 /*
  10  * Common fields provided in kmem_cache by all slab allocators
  11  * This struct is either used directly by the allocator (SLOB)
  12  * or the allocator must include definitions for all fields
  13  * provided in kmem_cache_common in their definition of kmem_cache.
  14  *
  15  * Once we can do anonymous structs (C11 standard) we could put a
  16  * anonymous struct definition in these allocators so that the
  17  * separate allocations in the kmem_cache structure of SLAB and
  18  * SLUB is no longer needed.
  19  */
  20 struct kmem_cache {
  21         unsigned int object_size;/* The original size of the object */
  22         unsigned int size;      /* The aligned/padded/added on size  */
  23         unsigned int align;     /* Alignment as calculated */
  24         slab_flags_t flags;     /* Active flags on the slab */
  25         unsigned int useroffset;/* Usercopy region offset */
  26         unsigned int usersize;  /* Usercopy region size */
  27         const char *name;       /* Slab name for sysfs */
  28         int refcount;           /* Use counter */
  29         void (*ctor)(void *);   /* Called on object slot creation */
  30         struct list_head list;  /* List of all slab caches on the system */
  31 };
  32
  33 #endif /* CONFIG_SLOB */
  34
  35 #ifdef CONFIG_SLAB
  36 #include <linux/slab_def.h>
  37 #endif
  38
  39 #ifdef CONFIG_SLUB
  40 #include <linux/slub_def.h>
  41 #endif
  42
  43 #include <linux/memcontrol.h>
  44 #include <linux/fault-inject.h>
  45 #include <linux/kasan.h>
  46 #include <linux/kmemleak.h>
  47 #include <linux/random.h>
  48 #include <linux/sched/mm.h>
  49
  50 /*
  51  * State of the slab allocator.
  52  *
  53  * This is used to describe the states of the allocator during bootup.
  54  * Allocators use this to gradually bootstrap themselves. Most allocators
  55  * have the problem that the structures used for managing slab caches are
  56  * allocated from slab caches themselves.
  57  */
  58 enum slab_state {
  59         DOWN,                   /* No slab functionality yet */
  60         PARTIAL,                /* SLUB: kmem_cache_node available */
  61         PARTIAL_NODE,           /* SLAB: kmalloc size for node struct available */
  62         UP,                     /* Slab caches usable but not all extras yet */
  63         FULL                    /* Everything is working */
  64 };
  65
  66 extern enum slab_state slab_state;
  67
  68 /* The slab cache mutex protects the management structures during changes */
  69 extern struct mutex slab_mutex;
  70
  71 /* The list of all slab caches on the system */
  72 extern struct list_head slab_caches;
  73
  74 /* The slab cache that manages slab cache information */
  75 extern struct kmem_cache *kmem_cache;
  76
  77 /* A table of kmalloc cache names and sizes */
  78 extern const struct kmalloc_info_struct {
  79         const char *name;
  80         unsigned int size;
  81 } kmalloc_info[];
  82
  83 #ifndef CONFIG_SLOB
  84 /* Kmalloc array related functions */
  85 void setup_kmalloc_cache_index_table(void);
  86 void create_kmalloc_caches(slab_flags_t);
  87
  88 /* Find the kmalloc slab corresponding for a certain size */
  89 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
  90 #endif
  91
  92
  93 /* Functions provided by the slab allocators */
  94 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
  95
  96 struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size,
  97                         slab_flags_t flags, unsigned int useroffset,
  98                         unsigned int usersize);
  99 extern void create_boot_cache(struct kmem_cache *, const char *name,
 100                         unsigned int size, slab_flags_t flags,
 101                         unsigned int useroffset, unsigned int usersize);
 102
 103 int slab_unmergeable(struct kmem_cache *s);
 104 struct kmem_cache *find_mergeable(unsigned size, unsigned align,
 105                 slab_flags_t flags, const char *name, void (*ctor)(void *));
 106 #ifndef CONFIG_SLOB
 107 struct kmem_cache *
 108 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 109                    slab_flags_t flags, void (*ctor)(void *));
 110
 111 slab_flags_t kmem_cache_flags(unsigned int object_size,
 112         slab_flags_t flags, const char *name,
 113         void (*ctor)(void *));
 114 #else
 115 static inline struct kmem_cache *
 116 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 117                    slab_flags_t flags, void (*ctor)(void *))
 118 { return NULL; }
 119
 120 static inline slab_flags_t kmem_cache_flags(unsigned int object_size,
 121         slab_flags_t flags, const char *name,
 122         void (*ctor)(void *))
 123 {
 124         return flags;
 125 }
 126 #endif
 127
 128
 129 /* Legal flag mask for kmem_cache_create(), for various configurations */
 130 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
 131                          SLAB_CACHE_DMA32 | SLAB_PANIC | \
 132                          SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
 133
 134 #if defined(CONFIG_DEBUG_SLAB)
 135 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 136 #elif defined(CONFIG_SLUB_DEBUG)
 137 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 138                           SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
 139 #else
 140 #define SLAB_DEBUG_FLAGS (0)
 141 #endif
 142
 143 #if defined(CONFIG_SLAB)
 144 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
 145                           SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
 146                           SLAB_ACCOUNT)
 147 #elif defined(CONFIG_SLUB)
 148 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
 149                           SLAB_TEMPORARY | SLAB_ACCOUNT)
 150 #else
 151 #define SLAB_CACHE_FLAGS (0)
 152 #endif
 153
 154 /* Common flags available with current configuration */
 155 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
 156
 157 /* Common flags permitted for kmem_cache_create */
 158 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
 159                               SLAB_RED_ZONE | \
 160                               SLAB_POISON | \
 161                               SLAB_STORE_USER | \
 162                               SLAB_TRACE | \
 163                               SLAB_CONSISTENCY_CHECKS | \
 164                               SLAB_MEM_SPREAD | \
 165                               SLAB_NOLEAKTRACE | \
 166                               SLAB_RECLAIM_ACCOUNT | \
 167                               SLAB_TEMPORARY | \
 168                               SLAB_ACCOUNT)
 169
 170 bool __kmem_cache_empty(struct kmem_cache *);
 171 int __kmem_cache_shutdown(struct kmem_cache *);
 172 void __kmem_cache_release(struct kmem_cache *);
 173 int __kmem_cache_shrink(struct kmem_cache *);
 174 void __kmemcg_cache_deactivate(struct kmem_cache *s);
 175 void __kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s);
 176 void slab_kmem_cache_release(struct kmem_cache *);
 177
 178 struct seq_file;
 179 struct file;
 180
 181 struct slabinfo {
 182         unsigned long active_objs;
 183         unsigned long num_objs;
 184         unsigned long active_slabs;
 185         unsigned long num_slabs;
 186         unsigned long shared_avail;
 187         unsigned int limit;
 188         unsigned int batchcount;
 189         unsigned int shared;
 190         unsigned int objects_per_slab;
 191         unsigned int cache_order;
 192 };
 193
 194 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
 195 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
 196 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 197                        size_t count, loff_t *ppos);
 198
 199 /*
 200  * Generic implementation of bulk operations
 201  * These are useful for situations in which the allocator cannot
 202  * perform optimizations. In that case segments of the object listed
 203  * may be allocated or freed using these operations.
 204  */
 205 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
 206 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
 207
 208 static inline int cache_vmstat_idx(struct kmem_cache *s)
 209 {
 210         return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
 211                 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE;
 212 }
 213
 214 #ifdef CONFIG_MEMCG_KMEM
 215
 216 /* List of all root caches. */
 217 extern struct list_head         slab_root_caches;
 218 #define root_caches_node        memcg_params.__root_caches_node
 219
 220 /*
 221  * Iterate over all memcg caches of the given root cache. The caller must hold
 222  * slab_mutex.
 223  */
 224 #define for_each_memcg_cache(iter, root) \
 225         list_for_each_entry(iter, &(root)->memcg_params.children, \
 226                             memcg_params.children_node)
 227
 228 static inline bool is_root_cache(struct kmem_cache *s)
 229 {
 230         return !s->memcg_params.root_cache;
 231 }
 232
 233 static inline bool slab_equal_or_root(struct kmem_cache *s,
 234                                       struct kmem_cache *p)
 235 {
 236         return p == s || p == s->memcg_params.root_cache;
 237 }
 238
 239 /*
 240  * We use suffixes to the name in memcg because we can't have caches
 241  * created in the system with the same name. But when we print them
 242  * locally, better refer to them with the base name
 243  */
 244 static inline const char *cache_name(struct kmem_cache *s)
 245 {
 246         if (!is_root_cache(s))
 247                 s = s->memcg_params.root_cache;
 248         return s->name;
 249 }
 250
 251 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 252 {
 253         if (is_root_cache(s))
 254                 return s;
 255         return s->memcg_params.root_cache;
 256 }
 257
 258 /*
 259  * Expects a pointer to a slab page. Please note, that PageSlab() check
 260  * isn't sufficient, as it returns true also for tail compound slab pages,
 261  * which do not have slab_cache pointer set.
 262  * So this function assumes that the page can pass PageHead() and PageSlab()
 263  * checks.
 264  *
 265  * The kmem_cache can be reparented asynchronously. The caller must ensure
 266  * the memcg lifetime, e.g. by taking rcu_read_lock() or cgroup_mutex.
 267  */
 268 static inline struct mem_cgroup *memcg_from_slab_page(struct page *page)
 269 {
 270         struct kmem_cache *s;
 271
 272         s = READ_ONCE(page->slab_cache);
 273         if (s && !is_root_cache(s))
 274                 return READ_ONCE(s->memcg_params.memcg);
 275
 276         return NULL;
 277 }
 278
 279 /*
 280  * Charge the slab page belonging to the non-root kmem_cache.
 281  * Can be called for non-root kmem_caches only.
 282  */
 283 static __always_inline int memcg_charge_slab(struct page *page,
 284                                              gfp_t gfp, int order,
 285                                              struct kmem_cache *s)
 286 {
 287         struct mem_cgroup *memcg;
 288         struct lruvec *lruvec;
 289         int ret;
 290
 291         rcu_read_lock();
 292         memcg = READ_ONCE(s->memcg_params.memcg);
 293         while (memcg && !css_tryget_online(&memcg->css))
 294                 memcg = parent_mem_cgroup(memcg);
 295         rcu_read_unlock();
 296
 297         if (unlikely(!memcg || mem_cgroup_is_root(memcg))) {
 298                 mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 299                                     (1 << order));
 300                 percpu_ref_get_many(&s->memcg_params.refcnt, 1 << order);
 301                 return 0;
 302         }
 303
 304         ret = memcg_kmem_charge_memcg(page, gfp, order, memcg);
 305         if (ret)
 306                 goto out;
 307
 308         lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg);
 309         mod_lruvec_state(lruvec, cache_vmstat_idx(s), 1 << order);
 310
 311         /* transer try_charge() page references to kmem_cache */
 312         percpu_ref_get_many(&s->memcg_params.refcnt, 1 << order);
 313         css_put_many(&memcg->css, 1 << order);
 314 out:
 315         css_put(&memcg->css);
 316         return ret;
 317 }
 318
 319 /*
 320  * Uncharge a slab page belonging to a non-root kmem_cache.
 321  * Can be called for non-root kmem_caches only.
 322  */
 323 static __always_inline void memcg_uncharge_slab(struct page *page, int order,
 324                                                 struct kmem_cache *s)
 325 {
 326         struct mem_cgroup *memcg;
 327         struct lruvec *lruvec;
 328
 329         rcu_read_lock();
 330         memcg = READ_ONCE(s->memcg_params.memcg);
 331         if (likely(!mem_cgroup_is_root(memcg))) {
 332                 lruvec = mem_cgroup_lruvec(page_pgdat(page), memcg);
 333                 mod_lruvec_state(lruvec, cache_vmstat_idx(s), -(1 << order));
 334                 memcg_kmem_uncharge_memcg(page, order, memcg);
 335         } else {
 336                 mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 337                                     -(1 << order));
 338         }
 339         rcu_read_unlock();
 340
 341         percpu_ref_put_many(&s->memcg_params.refcnt, 1 << order);
 342 }
 343
 344 extern void slab_init_memcg_params(struct kmem_cache *);
 345 extern void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg);
 346
 347 #else /* CONFIG_MEMCG_KMEM */
 348
 349 /* If !memcg, all caches are root. */
 350 #define slab_root_caches        slab_caches
 351 #define root_caches_node        list
 352
 353 #define for_each_memcg_cache(iter, root) \
 354         for ((void)(iter), (void)(root); 0; )
 355
 356 static inline bool is_root_cache(struct kmem_cache *s)
 357 {
 358         return true;
 359 }
 360
 361 static inline bool slab_equal_or_root(struct kmem_cache *s,
 362                                       struct kmem_cache *p)
 363 {
 364         return s == p;
 365 }
 366
 367 static inline const char *cache_name(struct kmem_cache *s)
 368 {
 369         return s->name;
 370 }
 371
 372 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
 373 {
 374         return s;
 375 }
 376
 377 static inline struct mem_cgroup *memcg_from_slab_page(struct page *page)
 378 {
 379         return NULL;
 380 }
 381
 382 static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
 383                                     struct kmem_cache *s)
 384 {
 385         return 0;
 386 }
 387
 388 static inline void memcg_uncharge_slab(struct page *page, int order,
 389                                        struct kmem_cache *s)
 390 {
 391 }
 392
 393 static inline void slab_init_memcg_params(struct kmem_cache *s)
 394 {
 395 }
 396
 397 static inline void memcg_link_cache(struct kmem_cache *s,
 398                                     struct mem_cgroup *memcg)
 399 {
 400 }
 401
 402 #endif /* CONFIG_MEMCG_KMEM */
 403
 404 static inline struct kmem_cache *virt_to_cache(const void *obj)
 405 {
 406         struct page *page;
 407
 408         page = virt_to_head_page(obj);
 409         if (WARN_ONCE(!PageSlab(page), "%s: Object is not a Slab page!\n",
 410                                         __func__))
 411                 return NULL;
 412         return page->slab_cache;
 413 }
 414
 415 static __always_inline int charge_slab_page(struct page *page,
 416                                             gfp_t gfp, int order,
 417                                             struct kmem_cache *s)
 418 {
 419         if (is_root_cache(s)) {
 420                 mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 421                                     1 << order);
 422                 return 0;
 423         }
 424
 425         return memcg_charge_slab(page, gfp, order, s);
 426 }
 427
 428 static __always_inline void uncharge_slab_page(struct page *page, int order,
 429                                                struct kmem_cache *s)
 430 {
 431         if (is_root_cache(s)) {
 432                 mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 433                                     -(1 << order));
 434                 return;
 435         }
 436
 437         memcg_uncharge_slab(page, order, s);
 438 }
 439
 440 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
 441 {
 442         struct kmem_cache *cachep;
 443
 444         /*
 445          * When kmemcg is not being used, both assignments should return the
 446          * same value. but we don't want to pay the assignment price in that
 447          * case. If it is not compiled in, the compiler should be smart enough
 448          * to not do even the assignment. In that case, slab_equal_or_root
 449          * will also be a constant.
 450          */
 451         if (!memcg_kmem_enabled() &&
 452             !IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
 453             !unlikely(s->flags & SLAB_CONSISTENCY_CHECKS))
 454                 return s;
 455
 456         cachep = virt_to_cache(x);
 457         WARN_ONCE(cachep && !slab_equal_or_root(cachep, s),
 458                   "%s: Wrong slab cache. %s but object is from %s\n",
 459                   __func__, s->name, cachep->name);
 460         return cachep;
 461 }
 462
 463 static inline size_t slab_ksize(const struct kmem_cache *s)
 464 {
 465 #ifndef CONFIG_SLUB
 466         return s->object_size;
 467
 468 #else /* CONFIG_SLUB */
 469 # ifdef CONFIG_SLUB_DEBUG
 470         /*
 471          * Debugging requires use of the padding between object
 472          * and whatever may come after it.
 473          */
 474         if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
 475                 return s->object_size;
 476 # endif
 477         if (s->flags & SLAB_KASAN)
 478                 return s->object_size;
 479         /*
 480          * If we have the need to store the freelist pointer
 481          * back there or track user information then we can
 482          * only use the space before that information.
 483          */
 484         if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
 485                 return s->inuse;
 486         /*
 487          * Else we can use all the padding etc for the allocation
 488          */
 489         return s->size;
 490 #endif
 491 }
 492
 493 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 494                                                      gfp_t flags)
 495 {
 496         flags &= gfp_allowed_mask;
 497
 498         fs_reclaim_acquire(flags);
 499         fs_reclaim_release(flags);
 500
 501         might_sleep_if(gfpflags_allow_blocking(flags));
 502
 503         if (should_failslab(s, flags))
 504                 return NULL;
 505
 506         if (memcg_kmem_enabled() &&
 507             ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
 508                 return memcg_kmem_get_cache(s);
 509
 510         return s;
 511 }
 512
 513 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
 514                                         size_t size, void **p)
 515 {
 516         size_t i;
 517
 518         flags &= gfp_allowed_mask;
 519         for (i = 0; i < size; i++) {
 520                 p[i] = kasan_slab_alloc(s, p[i], flags);
 521                 /* As p[i] might get tagged, call kmemleak hook after KASAN. */
 522                 kmemleak_alloc_recursive(p[i], s->object_size, 1,
 523                                          s->flags, flags);
 524         }
 525
 526         if (memcg_kmem_enabled())
 527                 memcg_kmem_put_cache(s);
 528 }
 529
 530 #ifndef CONFIG_SLOB
 531 /*
 532  * The slab lists for all objects.
 533  */
 534 struct kmem_cache_node {
 535         spinlock_t list_lock;
 536
 537 #ifdef CONFIG_SLAB
 538         struct list_head slabs_partial; /* partial list first, better asm code */
 539         struct list_head slabs_full;
 540         struct list_head slabs_free;
 541         unsigned long total_slabs;      /* length of all slab lists */
 542         unsigned long free_slabs;       /* length of free slab list only */
 543         unsigned long free_objects;
 544         unsigned int free_limit;
 545         unsigned int colour_next;       /* Per-node cache coloring */
 546         struct array_cache *shared;     /* shared per node */
 547         struct alien_cache **alien;     /* on other nodes */
 548         unsigned long next_reap;        /* updated without locking */
 549         int free_touched;               /* updated without locking */
 550 #endif
 551
 552 #ifdef CONFIG_SLUB
 553         unsigned long nr_partial;
 554         struct list_head partial;
 555 #ifdef CONFIG_SLUB_DEBUG
 556         atomic_long_t nr_slabs;
 557         atomic_long_t total_objects;
 558         struct list_head full;
 559 #endif
 560 #endif
 561
 562 };
 563
 564 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 565 {
 566         return s->node[node];
 567 }
 568
 569 /*
 570  * Iterator over all nodes. The body will be executed for each node that has
 571  * a kmem_cache_node structure allocated (which is true for all online nodes)
 572  */
 573 #define for_each_kmem_cache_node(__s, __node, __n) \
 574         for (__node = 0; __node < nr_node_ids; __node++) \
 575                  if ((__n = get_node(__s, __node)))
 576
 577 #endif
 578
 579 void *slab_start(struct seq_file *m, loff_t *pos);
 580 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
 581 void slab_stop(struct seq_file *m, void *p);
 582 void *memcg_slab_start(struct seq_file *m, loff_t *pos);
 583 void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos);
 584 void memcg_slab_stop(struct seq_file *m, void *p);
 585 int memcg_slab_show(struct seq_file *m, void *p);
 586
 587 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
 588 void dump_unreclaimable_slab(void);
 589 #else
 590 static inline void dump_unreclaimable_slab(void)
 591 {
 592 }
 593 #endif
 594
 595 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
 596
 597 #ifdef CONFIG_SLAB_FREELIST_RANDOM
 598 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
 599                         gfp_t gfp);
 600 void cache_random_seq_destroy(struct kmem_cache *cachep);
 601 #else
 602 static inline int cache_random_seq_create(struct kmem_cache *cachep,
 603                                         unsigned int count, gfp_t gfp)
 604 {
 605         return 0;
 606 }
 607 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
 608 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
 609
 610 static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
 611 {
 612         if (static_branch_unlikely(&init_on_alloc)) {
 613                 if (c->ctor)
 614                         return false;
 615                 if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
 616                         return flags & __GFP_ZERO;
 617                 return true;
 618         }
 619         return flags & __GFP_ZERO;
 620 }
 621
 622 static inline bool slab_want_init_on_free(struct kmem_cache *c)
 623 {
 624         if (static_branch_unlikely(&init_on_free))
 625                 return !(c->ctor ||
 626                          (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
 627         return false;
 628 }
 629
 630 #endif /* MM_SLAB_H */