1 /* SPDX-License-Identifier: GPL-2.0 */
5 * Internal slab definitions
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.
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.
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 */
33 #endif /* CONFIG_SLOB */
36 #include <linux/slab_def.h>
40 #include <linux/slub_def.h>
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>
51 * State of the slab allocator.
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.
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 */
66 extern enum slab_state slab_state;
68 /* The slab cache mutex protects the management structures during changes */
69 extern struct mutex slab_mutex;
71 /* The list of all slab caches on the system */
72 extern struct list_head slab_caches;
74 /* The slab cache that manages slab cache information */
75 extern struct kmem_cache *kmem_cache;
77 /* A table of kmalloc cache names and sizes */
78 extern const struct kmalloc_info_struct {
84 /* Kmalloc array related functions */
85 void setup_kmalloc_cache_index_table(void);
86 void create_kmalloc_caches(slab_flags_t);
88 /* Find the kmalloc slab corresponding for a certain size */
89 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
93 /* Functions provided by the slab allocators */
94 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
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);
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 *));
108 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
109 slab_flags_t flags, void (*ctor)(void *));
111 slab_flags_t kmem_cache_flags(unsigned int object_size,
112 slab_flags_t flags, const char *name,
113 void (*ctor)(void *));
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 *))
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 *))
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 )
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)
140 #define SLAB_DEBUG_FLAGS (0)
143 #if defined(CONFIG_SLAB)
144 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
145 SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
147 #elif defined(CONFIG_SLUB)
148 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
149 SLAB_TEMPORARY | SLAB_ACCOUNT)
151 #define SLAB_CACHE_FLAGS (0)
154 /* Common flags available with current configuration */
155 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
157 /* Common flags permitted for kmem_cache_create */
158 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
163 SLAB_CONSISTENCY_CHECKS | \
166 SLAB_RECLAIM_ACCOUNT | \
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 slab_kmem_cache_release(struct kmem_cache *);
181 unsigned long active_objs;
182 unsigned long num_objs;
183 unsigned long active_slabs;
184 unsigned long num_slabs;
185 unsigned long shared_avail;
187 unsigned int batchcount;
189 unsigned int objects_per_slab;
190 unsigned int cache_order;
193 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
194 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
195 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
196 size_t count, loff_t *ppos);
199 * Generic implementation of bulk operations
200 * These are useful for situations in which the allocator cannot
201 * perform optimizations. In that case segments of the object listed
202 * may be allocated or freed using these operations.
204 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
205 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
207 #ifdef CONFIG_MEMCG_KMEM
209 /* List of all root caches. */
210 extern struct list_head slab_root_caches;
211 #define root_caches_node memcg_params.__root_caches_node
214 * Iterate over all memcg caches of the given root cache. The caller must hold
217 #define for_each_memcg_cache(iter, root) \
218 list_for_each_entry(iter, &(root)->memcg_params.children, \
219 memcg_params.children_node)
221 static inline bool is_root_cache(struct kmem_cache *s)
223 return !s->memcg_params.root_cache;
226 static inline bool slab_equal_or_root(struct kmem_cache *s,
227 struct kmem_cache *p)
229 return p == s || p == s->memcg_params.root_cache;
233 * We use suffixes to the name in memcg because we can't have caches
234 * created in the system with the same name. But when we print them
235 * locally, better refer to them with the base name
237 static inline const char *cache_name(struct kmem_cache *s)
239 if (!is_root_cache(s))
240 s = s->memcg_params.root_cache;
245 * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
246 * That said the caller must assure the memcg's cache won't go away by either
247 * taking a css reference to the owner cgroup, or holding the slab_mutex.
249 static inline struct kmem_cache *
250 cache_from_memcg_idx(struct kmem_cache *s, int idx)
252 struct kmem_cache *cachep;
253 struct memcg_cache_array *arr;
256 arr = rcu_dereference(s->memcg_params.memcg_caches);
259 * Make sure we will access the up-to-date value. The code updating
260 * memcg_caches issues a write barrier to match this (see
261 * memcg_create_kmem_cache()).
263 cachep = READ_ONCE(arr->entries[idx]);
269 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
271 if (is_root_cache(s))
273 return s->memcg_params.root_cache;
276 static __always_inline int memcg_charge_slab(struct page *page,
277 gfp_t gfp, int order,
278 struct kmem_cache *s)
280 if (is_root_cache(s))
282 return memcg_kmem_charge_memcg(page, gfp, order, s->memcg_params.memcg);
285 static __always_inline void memcg_uncharge_slab(struct page *page, int order,
286 struct kmem_cache *s)
288 memcg_kmem_uncharge(page, order);
291 extern void slab_init_memcg_params(struct kmem_cache *);
292 extern void memcg_link_cache(struct kmem_cache *s);
293 extern void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
294 void (*deact_fn)(struct kmem_cache *));
296 #else /* CONFIG_MEMCG_KMEM */
298 /* If !memcg, all caches are root. */
299 #define slab_root_caches slab_caches
300 #define root_caches_node list
302 #define for_each_memcg_cache(iter, root) \
303 for ((void)(iter), (void)(root); 0; )
305 static inline bool is_root_cache(struct kmem_cache *s)
310 static inline bool slab_equal_or_root(struct kmem_cache *s,
311 struct kmem_cache *p)
316 static inline const char *cache_name(struct kmem_cache *s)
321 static inline struct kmem_cache *
322 cache_from_memcg_idx(struct kmem_cache *s, int idx)
327 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
332 static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
333 struct kmem_cache *s)
338 static inline void memcg_uncharge_slab(struct page *page, int order,
339 struct kmem_cache *s)
343 static inline void slab_init_memcg_params(struct kmem_cache *s)
347 static inline void memcg_link_cache(struct kmem_cache *s)
351 #endif /* CONFIG_MEMCG_KMEM */
353 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
355 struct kmem_cache *cachep;
359 * When kmemcg is not being used, both assignments should return the
360 * same value. but we don't want to pay the assignment price in that
361 * case. If it is not compiled in, the compiler should be smart enough
362 * to not do even the assignment. In that case, slab_equal_or_root
363 * will also be a constant.
365 if (!memcg_kmem_enabled() &&
366 !unlikely(s->flags & SLAB_CONSISTENCY_CHECKS))
369 page = virt_to_head_page(x);
370 cachep = page->slab_cache;
371 if (slab_equal_or_root(cachep, s))
374 pr_err("%s: Wrong slab cache. %s but object is from %s\n",
375 __func__, s->name, cachep->name);
380 static inline size_t slab_ksize(const struct kmem_cache *s)
383 return s->object_size;
385 #else /* CONFIG_SLUB */
386 # ifdef CONFIG_SLUB_DEBUG
388 * Debugging requires use of the padding between object
389 * and whatever may come after it.
391 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
392 return s->object_size;
394 if (s->flags & SLAB_KASAN)
395 return s->object_size;
397 * If we have the need to store the freelist pointer
398 * back there or track user information then we can
399 * only use the space before that information.
401 if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
404 * Else we can use all the padding etc for the allocation
410 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
413 flags &= gfp_allowed_mask;
415 fs_reclaim_acquire(flags);
416 fs_reclaim_release(flags);
418 might_sleep_if(gfpflags_allow_blocking(flags));
420 if (should_failslab(s, flags))
423 if (memcg_kmem_enabled() &&
424 ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
425 return memcg_kmem_get_cache(s);
430 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
431 size_t size, void **p)
435 flags &= gfp_allowed_mask;
436 for (i = 0; i < size; i++) {
437 p[i] = kasan_slab_alloc(s, p[i], flags);
438 /* As p[i] might get tagged, call kmemleak hook after KASAN. */
439 kmemleak_alloc_recursive(p[i], s->object_size, 1,
443 if (memcg_kmem_enabled())
444 memcg_kmem_put_cache(s);
449 * The slab lists for all objects.
451 struct kmem_cache_node {
452 spinlock_t list_lock;
455 struct list_head slabs_partial; /* partial list first, better asm code */
456 struct list_head slabs_full;
457 struct list_head slabs_free;
458 unsigned long total_slabs; /* length of all slab lists */
459 unsigned long free_slabs; /* length of free slab list only */
460 unsigned long free_objects;
461 unsigned int free_limit;
462 unsigned int colour_next; /* Per-node cache coloring */
463 struct array_cache *shared; /* shared per node */
464 struct alien_cache **alien; /* on other nodes */
465 unsigned long next_reap; /* updated without locking */
466 int free_touched; /* updated without locking */
470 unsigned long nr_partial;
471 struct list_head partial;
472 #ifdef CONFIG_SLUB_DEBUG
473 atomic_long_t nr_slabs;
474 atomic_long_t total_objects;
475 struct list_head full;
481 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
483 return s->node[node];
487 * Iterator over all nodes. The body will be executed for each node that has
488 * a kmem_cache_node structure allocated (which is true for all online nodes)
490 #define for_each_kmem_cache_node(__s, __node, __n) \
491 for (__node = 0; __node < nr_node_ids; __node++) \
492 if ((__n = get_node(__s, __node)))
496 void *slab_start(struct seq_file *m, loff_t *pos);
497 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
498 void slab_stop(struct seq_file *m, void *p);
499 void *memcg_slab_start(struct seq_file *m, loff_t *pos);
500 void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos);
501 void memcg_slab_stop(struct seq_file *m, void *p);
502 int memcg_slab_show(struct seq_file *m, void *p);
504 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
505 void dump_unreclaimable_slab(void);
507 static inline void dump_unreclaimable_slab(void)
512 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
514 #ifdef CONFIG_SLAB_FREELIST_RANDOM
515 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
517 void cache_random_seq_destroy(struct kmem_cache *cachep);
519 static inline int cache_random_seq_create(struct kmem_cache *cachep,
520 unsigned int count, gfp_t gfp)
524 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
525 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
527 #endif /* MM_SLAB_H */