include/linux/slab_def.h

   1 #ifndef _LINUX_SLAB_DEF_H
   2 #define _LINUX_SLAB_DEF_H
   3
   4 /*
   5  * Definitions unique to the original Linux SLAB allocator.
   6  *
   7  * What we provide here is a way to optimize the frequent kmalloc
   8  * calls in the kernel by selecting the appropriate general cache
   9  * if kmalloc was called with a size that can be established at
  10  * compile time.
  11  */
  12
  13 #include <linux/init.h>
  14 #include <linux/compiler.h>
  15
  16 /*
  17  * struct kmem_cache
  18  *
  19  * manages a cache.
  20  */
  21
  22 struct kmem_cache {
  23 /* 1) Cache tunables. Protected by cache_chain_mutex */
  24         unsigned int batchcount;
  25         unsigned int limit;
  26         unsigned int shared;
  27
  28         unsigned int size;
  29         u32 reciprocal_buffer_size;
  30 /* 2) touched by every alloc & free from the backend */
  31
  32         unsigned int flags;             /* constant flags */
  33         unsigned int num;               /* # of objs per slab */
  34
  35 /* 3) cache_grow/shrink */
  36         /* order of pgs per slab (2^n) */
  37         unsigned int gfporder;
  38
  39         /* force GFP flags, e.g. GFP_DMA */
  40         gfp_t allocflags;
  41
  42         size_t colour;                  /* cache colouring range */
  43         unsigned int colour_off;        /* colour offset */
  44         struct kmem_cache *slabp_cache;
  45         unsigned int slab_size;
  46
  47         /* constructor func */
  48         void (*ctor)(void *obj);
  49
  50 /* 4) cache creation/removal */
  51         const char *name;
  52         struct list_head list;
  53         int refcount;
  54         int object_size;
  55         int align;
  56
  57 /* 5) statistics */
  58 #ifdef CONFIG_DEBUG_SLAB
  59         unsigned long num_active;
  60         unsigned long num_allocations;
  61         unsigned long high_mark;
  62         unsigned long grown;
  63         unsigned long reaped;
  64         unsigned long errors;
  65         unsigned long max_freeable;
  66         unsigned long node_allocs;
  67         unsigned long node_frees;
  68         unsigned long node_overflow;
  69         atomic_t allochit;
  70         atomic_t allocmiss;
  71         atomic_t freehit;
  72         atomic_t freemiss;
  73
  74         /*
  75          * If debugging is enabled, then the allocator can add additional
  76          * fields and/or padding to every object. size contains the total
  77          * object size including these internal fields, the following two
  78          * variables contain the offset to the user object and its size.
  79          */
  80         int obj_offset;
  81 #endif /* CONFIG_DEBUG_SLAB */
  82 #ifdef CONFIG_MEMCG_KMEM
  83         struct memcg_cache_params *memcg_params;
  84 #endif
  85
  86 /* 6) per-cpu/per-node data, touched during every alloc/free */
  87         /*
  88          * We put array[] at the end of kmem_cache, because we want to size
  89          * this array to nr_cpu_ids slots instead of NR_CPUS
  90          * (see kmem_cache_init())
  91          * We still use [NR_CPUS] and not [1] or [0] because cache_cache
  92          * is statically defined, so we reserve the max number of cpus.
  93          *
  94          * We also need to guarantee that the list is able to accomodate a
  95          * pointer for each node since "nodelists" uses the remainder of
  96          * available pointers.
  97          */
  98         struct kmem_cache_node **node;
  99         struct array_cache *array[NR_CPUS + MAX_NUMNODES];
 100         /*
 101          * Do not add fields after array[]
 102          */
 103 };
 104
 105 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 106 void *__kmalloc(size_t size, gfp_t flags);
 107
 108 #ifdef CONFIG_TRACING
 109 extern void *kmem_cache_alloc_trace(struct kmem_cache *, gfp_t, size_t);
 110 #else
 111 static __always_inline void *
 112 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
 113 {
 114         return kmem_cache_alloc(cachep, flags);
 115 }
 116 #endif
 117
 118 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 119 {
 120         struct kmem_cache *cachep;
 121         void *ret;
 122
 123         if (__builtin_constant_p(size)) {
 124                 int i;
 125
 126                 if (!size)
 127                         return ZERO_SIZE_PTR;
 128
 129                 if (WARN_ON_ONCE(size > KMALLOC_MAX_SIZE))
 130                         return NULL;
 131
 132                 i = kmalloc_index(size);
 133
 134 #ifdef CONFIG_ZONE_DMA
 135                 if (flags & GFP_DMA)
 136                         cachep = kmalloc_dma_caches[i];
 137                 else
 138 #endif
 139                         cachep = kmalloc_caches[i];
 140
 141                 ret = kmem_cache_alloc_trace(cachep, flags, size);
 142
 143                 return ret;
 144         }
 145         return __kmalloc(size, flags);
 146 }
 147
 148 #ifdef CONFIG_NUMA
 149 extern void *__kmalloc_node(size_t size, gfp_t flags, int node);
 150 extern void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 151
 152 #ifdef CONFIG_TRACING
 153 extern void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
 154                                          gfp_t flags,
 155                                          int nodeid,
 156                                          size_t size);
 157 #else
 158 static __always_inline void *
 159 kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
 160                             gfp_t flags,
 161                             int nodeid,
 162                             size_t size)
 163 {
 164         return kmem_cache_alloc_node(cachep, flags, nodeid);
 165 }
 166 #endif
 167
 168 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 169 {
 170         struct kmem_cache *cachep;
 171
 172         if (__builtin_constant_p(size)) {
 173                 int i;
 174
 175                 if (!size)
 176                         return ZERO_SIZE_PTR;
 177
 178                 if (WARN_ON_ONCE(size > KMALLOC_MAX_SIZE))
 179                         return NULL;
 180
 181                 i = kmalloc_index(size);
 182
 183 #ifdef CONFIG_ZONE_DMA
 184                 if (flags & GFP_DMA)
 185                         cachep = kmalloc_dma_caches[i];
 186                 else
 187 #endif
 188                         cachep = kmalloc_caches[i];
 189
 190                 return kmem_cache_alloc_node_trace(cachep, flags, node, size);
 191         }
 192         return __kmalloc_node(size, flags, node);
 193 }
 194
 195 #endif  /* CONFIG_NUMA */
 196
 197 #endif  /* _LINUX_SLAB_DEF_H */