/* SPDX-License-Identifier: GPL-2.0 */ #ifndef MM_SLAB_H #define MM_SLAB_H #include #include #include #include #include #include #include #include #include /* * Internal slab definitions */ #ifdef CONFIG_64BIT # ifdef system_has_cmpxchg128 # define system_has_freelist_aba() system_has_cmpxchg128() # define try_cmpxchg_freelist try_cmpxchg128 # endif #define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg128 typedef u128 freelist_full_t; #else /* CONFIG_64BIT */ # ifdef system_has_cmpxchg64 # define system_has_freelist_aba() system_has_cmpxchg64() # define try_cmpxchg_freelist try_cmpxchg64 # endif #define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg64 typedef u64 freelist_full_t; #endif /* CONFIG_64BIT */ #if defined(system_has_freelist_aba) && !defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) #undef system_has_freelist_aba #endif /* * Freelist pointer and counter to cmpxchg together, avoids the typical ABA * problems with cmpxchg of just a pointer. */ typedef union { struct { void *freelist; unsigned long counter; }; freelist_full_t full; } freelist_aba_t; /* Reuses the bits in struct page */ struct slab { unsigned long __page_flags; struct kmem_cache *slab_cache; union { struct { union { struct list_head slab_list; #ifdef CONFIG_SLUB_CPU_PARTIAL struct { struct slab *next; int slabs; /* Nr of slabs left */ }; #endif }; /* Double-word boundary */ union { struct { void *freelist; /* first free object */ union { unsigned long counters; struct { unsigned inuse:16; unsigned objects:15; /* * If slab debugging is enabled then the * frozen bit can be reused to indicate * that the slab was corrupted */ unsigned frozen:1; }; }; }; #ifdef system_has_freelist_aba freelist_aba_t freelist_counter; #endif }; }; struct rcu_head rcu_head; }; unsigned int __page_type; atomic_t __page_refcount; #ifdef CONFIG_SLAB_OBJ_EXT unsigned long obj_exts; #endif }; #define SLAB_MATCH(pg, sl) \ static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl)) SLAB_MATCH(flags, __page_flags); SLAB_MATCH(compound_head, slab_cache); /* Ensure bit 0 is clear */ SLAB_MATCH(_refcount, __page_refcount); #ifdef CONFIG_MEMCG SLAB_MATCH(memcg_data, obj_exts); #elif defined(CONFIG_SLAB_OBJ_EXT) SLAB_MATCH(_unused_slab_obj_exts, obj_exts); #endif #undef SLAB_MATCH static_assert(sizeof(struct slab) <= sizeof(struct page)); #if defined(system_has_freelist_aba) static_assert(IS_ALIGNED(offsetof(struct slab, freelist), sizeof(freelist_aba_t))); #endif /** * folio_slab - Converts from folio to slab. * @folio: The folio. * * Currently struct slab is a different representation of a folio where * folio_test_slab() is true. * * Return: The slab which contains this folio. */ #define folio_slab(folio) (_Generic((folio), \ const struct folio *: (const struct slab *)(folio), \ struct folio *: (struct slab *)(folio))) /** * slab_folio - The folio allocated for a slab * @slab: The slab. * * Slabs are allocated as folios that contain the individual objects and are * using some fields in the first struct page of the folio - those fields are * now accessed by struct slab. It is occasionally necessary to convert back to * a folio in order to communicate with the rest of the mm. Please use this * helper function instead of casting yourself, as the implementation may change * in the future. */ #define slab_folio(s) (_Generic((s), \ const struct slab *: (const struct folio *)s, \ struct slab *: (struct folio *)s)) /** * page_slab - Converts from first struct page to slab. * @p: The first (either head of compound or single) page of slab. * * A temporary wrapper to convert struct page to struct slab in situations where * we know the page is the compound head, or single order-0 page. * * Long-term ideally everything would work with struct slab directly or go * through folio to struct slab. * * Return: The slab which contains this page */ #define page_slab(p) (_Generic((p), \ const struct page *: (const struct slab *)(p), \ struct page *: (struct slab *)(p))) /** * slab_page - The first struct page allocated for a slab * @slab: The slab. * * A convenience wrapper for converting slab to the first struct page of the * underlying folio, to communicate with code not yet converted to folio or * struct slab. */ #define slab_page(s) folio_page(slab_folio(s), 0) /* * If network-based swap is enabled, sl*b must keep track of whether pages * were allocated from pfmemalloc reserves. */ static inline bool slab_test_pfmemalloc(const struct slab *slab) { return folio_test_active(slab_folio(slab)); } static inline void slab_set_pfmemalloc(struct slab *slab) { folio_set_active(slab_folio(slab)); } static inline void slab_clear_pfmemalloc(struct slab *slab) { folio_clear_active(slab_folio(slab)); } static inline void __slab_clear_pfmemalloc(struct slab *slab) { __folio_clear_active(slab_folio(slab)); } static inline void *slab_address(const struct slab *slab) { return folio_address(slab_folio(slab)); } static inline int slab_nid(const struct slab *slab) { return folio_nid(slab_folio(slab)); } static inline pg_data_t *slab_pgdat(const struct slab *slab) { return folio_pgdat(slab_folio(slab)); } static inline struct slab *virt_to_slab(const void *addr) { struct folio *folio = virt_to_folio(addr); if (!folio_test_slab(folio)) return NULL; return folio_slab(folio); } static inline int slab_order(const struct slab *slab) { return folio_order(slab_folio(slab)); } static inline size_t slab_size(const struct slab *slab) { return PAGE_SIZE << slab_order(slab); } #ifdef CONFIG_SLUB_CPU_PARTIAL #define slub_percpu_partial(c) ((c)->partial) #define slub_set_percpu_partial(c, p) \ ({ \ slub_percpu_partial(c) = (p)->next; \ }) #define slub_percpu_partial_read_once(c) READ_ONCE(slub_percpu_partial(c)) #else #define slub_percpu_partial(c) NULL #define slub_set_percpu_partial(c, p) #define slub_percpu_partial_read_once(c) NULL #endif // CONFIG_SLUB_CPU_PARTIAL /* * Word size structure that can be atomically updated or read and that * contains both the order and the number of objects that a slab of the * given order would contain. */ struct kmem_cache_order_objects { unsigned int x; }; /* * Slab cache management. */ struct kmem_cache { #ifndef CONFIG_SLUB_TINY struct kmem_cache_cpu __percpu *cpu_slab; #endif /* Used for retrieving partial slabs, etc. */ slab_flags_t flags; unsigned long min_partial; unsigned int size; /* Object size including metadata */ unsigned int object_size; /* Object size without metadata */ struct reciprocal_value reciprocal_size; unsigned int offset; /* Free pointer offset */ #ifdef CONFIG_SLUB_CPU_PARTIAL /* Number of per cpu partial objects to keep around */ unsigned int cpu_partial; /* Number of per cpu partial slabs to keep around */ unsigned int cpu_partial_slabs; #endif struct kmem_cache_order_objects oo; /* Allocation and freeing of slabs */ struct kmem_cache_order_objects min; gfp_t allocflags; /* gfp flags to use on each alloc */ int refcount; /* Refcount for slab cache destroy */ void (*ctor)(void *object); /* Object constructor */ unsigned int inuse; /* Offset to metadata */ unsigned int align; /* Alignment */ unsigned int red_left_pad; /* Left redzone padding size */ const char *name; /* Name (only for display!) */ struct list_head list; /* List of slab caches */ #ifdef CONFIG_SYSFS struct kobject kobj; /* For sysfs */ #endif #ifdef CONFIG_SLAB_FREELIST_HARDENED unsigned long random; #endif #ifdef CONFIG_NUMA /* * Defragmentation by allocating from a remote node. */ unsigned int remote_node_defrag_ratio; #endif #ifdef CONFIG_SLAB_FREELIST_RANDOM unsigned int *random_seq; #endif #ifdef CONFIG_KASAN_GENERIC struct kasan_cache kasan_info; #endif #ifdef CONFIG_HARDENED_USERCOPY unsigned int useroffset; /* Usercopy region offset */ unsigned int usersize; /* Usercopy region size */ #endif struct kmem_cache_node *node[MAX_NUMNODES]; }; #if defined(CONFIG_SYSFS) && !defined(CONFIG_SLUB_TINY) #define SLAB_SUPPORTS_SYSFS 1 void sysfs_slab_unlink(struct kmem_cache *s); void sysfs_slab_release(struct kmem_cache *s); #else static inline void sysfs_slab_unlink(struct kmem_cache *s) { } static inline void sysfs_slab_release(struct kmem_cache *s) { } #endif void *fixup_red_left(struct kmem_cache *s, void *p); static inline void *nearest_obj(struct kmem_cache *cache, const struct slab *slab, void *x) { void *object = x - (x - slab_address(slab)) % cache->size; void *last_object = slab_address(slab) + (slab->objects - 1) * cache->size; void *result = (unlikely(object > last_object)) ? last_object : object; result = fixup_red_left(cache, result); return result; } /* Determine object index from a given position */ static inline unsigned int __obj_to_index(const struct kmem_cache *cache, void *addr, void *obj) { return reciprocal_divide(kasan_reset_tag(obj) - addr, cache->reciprocal_size); } static inline unsigned int obj_to_index(const struct kmem_cache *cache, const struct slab *slab, void *obj) { if (is_kfence_address(obj)) return 0; return __obj_to_index(cache, slab_address(slab), obj); } static inline int objs_per_slab(const struct kmem_cache *cache, const struct slab *slab) { return slab->objects; } /* * State of the slab allocator. * * This is used to describe the states of the allocator during bootup. * Allocators use this to gradually bootstrap themselves. Most allocators * have the problem that the structures used for managing slab caches are * allocated from slab caches themselves. */ enum slab_state { DOWN, /* No slab functionality yet */ PARTIAL, /* SLUB: kmem_cache_node available */ UP, /* Slab caches usable but not all extras yet */ FULL /* Everything is working */ }; extern enum slab_state slab_state; /* The slab cache mutex protects the management structures during changes */ extern struct mutex slab_mutex; /* The list of all slab caches on the system */ extern struct list_head slab_caches; /* The slab cache that manages slab cache information */ extern struct kmem_cache *kmem_cache; /* A table of kmalloc cache names and sizes */ extern const struct kmalloc_info_struct { const char *name[NR_KMALLOC_TYPES]; unsigned int size; } kmalloc_info[]; /* Kmalloc array related functions */ void setup_kmalloc_cache_index_table(void); void create_kmalloc_caches(void); extern u8 kmalloc_size_index[24]; static inline unsigned int size_index_elem(unsigned int bytes) { return (bytes - 1) / 8; } /* * Find the kmem_cache structure that serves a given size of * allocation * * This assumes size is larger than zero and not larger than * KMALLOC_MAX_CACHE_SIZE and the caller must check that. */ static inline struct kmem_cache * kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, unsigned long caller) { unsigned int index; if (!b) b = &kmalloc_caches[kmalloc_type(flags, caller)]; if (size <= 192) index = kmalloc_size_index[size_index_elem(size)]; else index = fls(size - 1); return (*b)[index]; } gfp_t kmalloc_fix_flags(gfp_t flags); /* Functions provided by the slab allocators */ int do_kmem_cache_create(struct kmem_cache *s, const char *name, unsigned int size, struct kmem_cache_args *args, slab_flags_t flags); void __init kmem_cache_init(void); extern void create_boot_cache(struct kmem_cache *, const char *name, unsigned int size, slab_flags_t flags, unsigned int useroffset, unsigned int usersize); int slab_unmergeable(struct kmem_cache *s); struct kmem_cache *find_mergeable(unsigned size, unsigned align, slab_flags_t flags, const char *name, void (*ctor)(void *)); struct kmem_cache * __kmem_cache_alias(const char *name, unsigned int size, unsigned int align, slab_flags_t flags, void (*ctor)(void *)); slab_flags_t kmem_cache_flags(slab_flags_t flags, const char *name); static inline bool is_kmalloc_cache(struct kmem_cache *s) { return (s->flags & SLAB_KMALLOC); } static inline bool is_kmalloc_normal(struct kmem_cache *s) { if (!is_kmalloc_cache(s)) return false; return !(s->flags & (SLAB_CACHE_DMA|SLAB_ACCOUNT|SLAB_RECLAIM_ACCOUNT)); } /* Legal flag mask for kmem_cache_create(), for various configurations */ #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \ SLAB_CACHE_DMA32 | SLAB_PANIC | \ SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS ) #ifdef CONFIG_SLUB_DEBUG #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ SLAB_TRACE | SLAB_CONSISTENCY_CHECKS) #else #define SLAB_DEBUG_FLAGS (0) #endif #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \ SLAB_TEMPORARY | SLAB_ACCOUNT | \ SLAB_NO_USER_FLAGS | SLAB_KMALLOC | SLAB_NO_MERGE) /* Common flags available with current configuration */ #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS) /* Common flags permitted for kmem_cache_create */ #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \ SLAB_RED_ZONE | \ SLAB_POISON | \ SLAB_STORE_USER | \ SLAB_TRACE | \ SLAB_CONSISTENCY_CHECKS | \ SLAB_NOLEAKTRACE | \ SLAB_RECLAIM_ACCOUNT | \ SLAB_TEMPORARY | \ SLAB_ACCOUNT | \ SLAB_KMALLOC | \ SLAB_NO_MERGE | \ SLAB_NO_USER_FLAGS) bool __kmem_cache_empty(struct kmem_cache *); int __kmem_cache_shutdown(struct kmem_cache *); void __kmem_cache_release(struct kmem_cache *); int __kmem_cache_shrink(struct kmem_cache *); void slab_kmem_cache_release(struct kmem_cache *); struct seq_file; struct file; struct slabinfo { unsigned long active_objs; unsigned long num_objs; unsigned long active_slabs; unsigned long num_slabs; unsigned long shared_avail; unsigned int limit; unsigned int batchcount; unsigned int shared; unsigned int objects_per_slab; unsigned int cache_order; }; void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo); #ifdef CONFIG_SLUB_DEBUG #ifdef CONFIG_SLUB_DEBUG_ON DECLARE_STATIC_KEY_TRUE(slub_debug_enabled); #else DECLARE_STATIC_KEY_FALSE(slub_debug_enabled); #endif extern void print_tracking(struct kmem_cache *s, void *object); long validate_slab_cache(struct kmem_cache *s); static inline bool __slub_debug_enabled(void) { return static_branch_unlikely(&slub_debug_enabled); } #else static inline void print_tracking(struct kmem_cache *s, void *object) { } static inline bool __slub_debug_enabled(void) { return false; } #endif /* * Returns true if any of the specified slab_debug flags is enabled for the * cache. Use only for flags parsed by setup_slub_debug() as it also enables * the static key. */ static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags) { if (IS_ENABLED(CONFIG_SLUB_DEBUG)) VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS)); if (__slub_debug_enabled()) return s->flags & flags; return false; } #if IS_ENABLED(CONFIG_SLUB_DEBUG) && IS_ENABLED(CONFIG_KUNIT) bool slab_in_kunit_test(void); #else static inline bool slab_in_kunit_test(void) { return false; } #endif #ifdef CONFIG_SLAB_OBJ_EXT /* * slab_obj_exts - get the pointer to the slab object extension vector * associated with a slab. * @slab: a pointer to the slab struct * * Returns a pointer to the object extension vector associated with the slab, * or NULL if no such vector has been associated yet. */ static inline struct slabobj_ext *slab_obj_exts(struct slab *slab) { unsigned long obj_exts = READ_ONCE(slab->obj_exts); #ifdef CONFIG_MEMCG VM_BUG_ON_PAGE(obj_exts && !(obj_exts & MEMCG_DATA_OBJEXTS), slab_page(slab)); VM_BUG_ON_PAGE(obj_exts & MEMCG_DATA_KMEM, slab_page(slab)); #endif return (struct slabobj_ext *)(obj_exts & ~OBJEXTS_FLAGS_MASK); } int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, gfp_t gfp, bool new_slab); #else /* CONFIG_SLAB_OBJ_EXT */ static inline struct slabobj_ext *slab_obj_exts(struct slab *slab) { return NULL; } #endif /* CONFIG_SLAB_OBJ_EXT */ static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s) { return (s->flags & SLAB_RECLAIM_ACCOUNT) ? NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B; } #ifdef CONFIG_MEMCG bool __memcg_slab_post_alloc_hook(struct kmem_cache *s, struct list_lru *lru, gfp_t flags, size_t size, void **p); void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p, int objects, struct slabobj_ext *obj_exts); #endif size_t __ksize(const void *objp); static inline size_t slab_ksize(const struct kmem_cache *s) { #ifdef CONFIG_SLUB_DEBUG /* * Debugging requires use of the padding between object * and whatever may come after it. */ if (s->flags & (SLAB_RED_ZONE | SLAB_POISON)) return s->object_size; #endif if (s->flags & SLAB_KASAN) return s->object_size; /* * If we have the need to store the freelist pointer * back there or track user information then we can * only use the space before that information. */ if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER)) return s->inuse; /* * Else we can use all the padding etc for the allocation */ return s->size; } #ifdef CONFIG_SLUB_DEBUG void dump_unreclaimable_slab(void); #else static inline void dump_unreclaimable_slab(void) { } #endif void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr); #ifdef CONFIG_SLAB_FREELIST_RANDOM int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, gfp_t gfp); void cache_random_seq_destroy(struct kmem_cache *cachep); #else static inline int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, gfp_t gfp) { return 0; } static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { } #endif /* CONFIG_SLAB_FREELIST_RANDOM */ static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c) { if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, &init_on_alloc)) { if (c->ctor) return false; if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) return flags & __GFP_ZERO; return true; } return flags & __GFP_ZERO; } static inline bool slab_want_init_on_free(struct kmem_cache *c) { if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON, &init_on_free)) return !(c->ctor || (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))); return false; } #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG) void debugfs_slab_release(struct kmem_cache *); #else static inline void debugfs_slab_release(struct kmem_cache *s) { } #endif #ifdef CONFIG_PRINTK #define KS_ADDRS_COUNT 16 struct kmem_obj_info { void *kp_ptr; struct slab *kp_slab; void *kp_objp; unsigned long kp_data_offset; struct kmem_cache *kp_slab_cache; void *kp_ret; void *kp_stack[KS_ADDRS_COUNT]; void *kp_free_stack[KS_ADDRS_COUNT]; }; void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab); #endif void __check_heap_object(const void *ptr, unsigned long n, const struct slab *slab, bool to_user); static inline bool slub_debug_orig_size(struct kmem_cache *s) { return (kmem_cache_debug_flags(s, SLAB_STORE_USER) && (s->flags & SLAB_KMALLOC)); } #ifdef CONFIG_SLUB_DEBUG void skip_orig_size_check(struct kmem_cache *s, const void *object); #endif #endif /* MM_SLAB_H */