1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_SLAB_DEF_H 3 #define _LINUX_SLAB_DEF_H 4 5 #include <linux/reciprocal_div.h> 6 7 /* 8 * Definitions unique to the original Linux SLAB allocator. 9 */ 10 11 struct kmem_cache { 12 struct array_cache __percpu *cpu_cache; 13 14 /* 1) Cache tunables. Protected by slab_mutex */ 15 unsigned int batchcount; 16 unsigned int limit; 17 unsigned int shared; 18 19 unsigned int size; 20 struct reciprocal_value reciprocal_buffer_size; 21 /* 2) touched by every alloc & free from the backend */ 22 23 slab_flags_t flags; /* constant flags */ 24 unsigned int num; /* # of objs per slab */ 25 26 /* 3) cache_grow/shrink */ 27 /* order of pgs per slab (2^n) */ 28 unsigned int gfporder; 29 30 /* force GFP flags, e.g. GFP_DMA */ 31 gfp_t allocflags; 32 33 size_t colour; /* cache colouring range */ 34 unsigned int colour_off; /* colour offset */ 35 struct kmem_cache *freelist_cache; 36 unsigned int freelist_size; 37 38 /* constructor func */ 39 void (*ctor)(void *obj); 40 41 /* 4) cache creation/removal */ 42 const char *name; 43 struct list_head list; 44 int refcount; 45 int object_size; 46 int align; 47 48 /* 5) statistics */ 49 #ifdef CONFIG_DEBUG_SLAB 50 unsigned long num_active; 51 unsigned long num_allocations; 52 unsigned long high_mark; 53 unsigned long grown; 54 unsigned long reaped; 55 unsigned long errors; 56 unsigned long max_freeable; 57 unsigned long node_allocs; 58 unsigned long node_frees; 59 unsigned long node_overflow; 60 atomic_t allochit; 61 atomic_t allocmiss; 62 atomic_t freehit; 63 atomic_t freemiss; 64 65 /* 66 * If debugging is enabled, then the allocator can add additional 67 * fields and/or padding to every object. 'size' contains the total 68 * object size including these internal fields, while 'obj_offset' 69 * and 'object_size' contain the offset to the user object and its 70 * size. 71 */ 72 int obj_offset; 73 #endif /* CONFIG_DEBUG_SLAB */ 74 75 #ifdef CONFIG_MEMCG 76 struct memcg_cache_params memcg_params; 77 #endif 78 #ifdef CONFIG_KASAN 79 struct kasan_cache kasan_info; 80 #endif 81 82 #ifdef CONFIG_SLAB_FREELIST_RANDOM 83 unsigned int *random_seq; 84 #endif 85 86 unsigned int useroffset; /* Usercopy region offset */ 87 unsigned int usersize; /* Usercopy region size */ 88 89 struct kmem_cache_node *node[MAX_NUMNODES]; 90 }; 91 92 static inline void *nearest_obj(struct kmem_cache *cache, struct page *page, 93 void *x) 94 { 95 void *object = x - (x - page->s_mem) % cache->size; 96 void *last_object = page->s_mem + (cache->num - 1) * cache->size; 97 98 if (unlikely(object > last_object)) 99 return last_object; 100 else 101 return object; 102 } 103 104 /* 105 * We want to avoid an expensive divide : (offset / cache->size) 106 * Using the fact that size is a constant for a particular cache, 107 * we can replace (offset / cache->size) by 108 * reciprocal_divide(offset, cache->reciprocal_buffer_size) 109 */ 110 static inline unsigned int obj_to_index(const struct kmem_cache *cache, 111 const struct page *page, void *obj) 112 { 113 u32 offset = (obj - page->s_mem); 114 return reciprocal_divide(offset, cache->reciprocal_buffer_size); 115 } 116 117 #endif /* _LINUX_SLAB_DEF_H */ 118