include/linux/slub_def.h

   1 #ifndef _LINUX_SLUB_DEF_H
   2 #define _LINUX_SLUB_DEF_H
   3
   4 /*
   5  * SLUB : A Slab allocator without object queues.
   6  *
   7  * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
   8  */
   9 #include <linux/types.h>
  10 #include <linux/gfp.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/kobject.h>
  13
  14 enum stat_item {
  15         ALLOC_FASTPATH,         /* Allocation from cpu slab */
  16         ALLOC_SLOWPATH,         /* Allocation by getting a new cpu slab */
  17         FREE_FASTPATH,          /* Free to cpu slub */
  18         FREE_SLOWPATH,          /* Freeing not to cpu slab */
  19         FREE_FROZEN,            /* Freeing to frozen slab */
  20         FREE_ADD_PARTIAL,       /* Freeing moves slab to partial list */
  21         FREE_REMOVE_PARTIAL,    /* Freeing removes last object */
  22         ALLOC_FROM_PARTIAL,     /* Cpu slab acquired from partial list */
  23         ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
  24         ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
  25         FREE_SLAB,              /* Slab freed to the page allocator */
  26         CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
  27         DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
  28         DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
  29         DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
  30         DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
  31         DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
  32         NR_SLUB_STAT_ITEMS };
  33
  34 struct kmem_cache_cpu {
  35         void **freelist;        /* Pointer to first free per cpu object */
  36         struct page *page;      /* The slab from which we are allocating */
  37         int node;               /* The node of the page (or -1 for debug) */
  38         unsigned int offset;    /* Freepointer offset (in word units) */
  39         unsigned int objsize;   /* Size of an object (from kmem_cache) */
  40 #ifdef CONFIG_SLUB_STATS
  41         unsigned stat[NR_SLUB_STAT_ITEMS];
  42 #endif
  43 };
  44
  45 struct kmem_cache_node {
  46         spinlock_t list_lock;   /* Protect partial list and nr_partial */
  47         unsigned long nr_partial;
  48         atomic_long_t nr_slabs;
  49         struct list_head partial;
  50 #ifdef CONFIG_SLUB_DEBUG
  51         struct list_head full;
  52 #endif
  53 };
  54
  55 /*
  56  * Slab cache management.
  57  */
  58 struct kmem_cache {
  59         /* Used for retriving partial slabs etc */
  60         unsigned long flags;
  61         int size;               /* The size of an object including meta data */
  62         int objsize;            /* The size of an object without meta data */
  63         int offset;             /* Free pointer offset. */
  64         int order;              /* Current preferred allocation order */
  65
  66         /*
  67          * Avoid an extra cache line for UP, SMP and for the node local to
  68          * struct kmem_cache.
  69          */
  70         struct kmem_cache_node local_node;
  71
  72         /* Allocation and freeing of slabs */
  73         int objects;            /* Number of objects in slab */
  74         gfp_t allocflags;       /* gfp flags to use on each alloc */
  75         int refcount;           /* Refcount for slab cache destroy */
  76         void (*ctor)(struct kmem_cache *, void *);
  77         int inuse;              /* Offset to metadata */
  78         int align;              /* Alignment */
  79         const char *name;       /* Name (only for display!) */
  80         struct list_head list;  /* List of slab caches */
  81 #ifdef CONFIG_SLUB_DEBUG
  82         struct kobject kobj;    /* For sysfs */
  83 #endif
  84
  85 #ifdef CONFIG_NUMA
  86         /*
  87          * Defragmentation by allocating from a remote node.
  88          */
  89         int remote_node_defrag_ratio;
  90         struct kmem_cache_node *node[MAX_NUMNODES];
  91 #endif
  92 #ifdef CONFIG_SMP
  93         struct kmem_cache_cpu *cpu_slab[NR_CPUS];
  94 #else
  95         struct kmem_cache_cpu cpu_slab;
  96 #endif
  97 };
  98
  99 /*
 100  * Kmalloc subsystem.
 101  */
 102 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
 103 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
 104 #else
 105 #define KMALLOC_MIN_SIZE 8
 106 #endif
 107
 108 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
 109
 110 /*
 111  * We keep the general caches in an array of slab caches that are used for
 112  * 2^x bytes of allocations.
 113  */
 114 extern struct kmem_cache kmalloc_caches[PAGE_SHIFT + 1];
 115
 116 /*
 117  * Sorry that the following has to be that ugly but some versions of GCC
 118  * have trouble with constant propagation and loops.
 119  */
 120 static __always_inline int kmalloc_index(size_t size)
 121 {
 122         if (!size)
 123                 return 0;
 124
 125         if (size <= KMALLOC_MIN_SIZE)
 126                 return KMALLOC_SHIFT_LOW;
 127
 128         if (size > 64 && size <= 96)
 129                 return 1;
 130         if (size > 128 && size <= 192)
 131                 return 2;
 132         if (size <=          8) return 3;
 133         if (size <=         16) return 4;
 134         if (size <=         32) return 5;
 135         if (size <=         64) return 6;
 136         if (size <=        128) return 7;
 137         if (size <=        256) return 8;
 138         if (size <=        512) return 9;
 139         if (size <=       1024) return 10;
 140         if (size <=   2 * 1024) return 11;
 141         if (size <=   4 * 1024) return 12;
 142 /*
 143  * The following is only needed to support architectures with a larger page
 144  * size than 4k.
 145  */
 146         if (size <=   8 * 1024) return 13;
 147         if (size <=  16 * 1024) return 14;
 148         if (size <=  32 * 1024) return 15;
 149         if (size <=  64 * 1024) return 16;
 150         if (size <= 128 * 1024) return 17;
 151         if (size <= 256 * 1024) return 18;
 152         if (size <= 512 * 1024) return 19;
 153         if (size <= 1024 * 1024) return 20;
 154         if (size <=  2 * 1024 * 1024) return 21;
 155         return -1;
 156
 157 /*
 158  * What we really wanted to do and cannot do because of compiler issues is:
 159  *      int i;
 160  *      for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 161  *              if (size <= (1 << i))
 162  *                      return i;
 163  */
 164 }
 165
 166 /*
 167  * Find the slab cache for a given combination of allocation flags and size.
 168  *
 169  * This ought to end up with a global pointer to the right cache
 170  * in kmalloc_caches.
 171  */
 172 static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
 173 {
 174         int index = kmalloc_index(size);
 175
 176         if (index == 0)
 177                 return NULL;
 178
 179         return &kmalloc_caches[index];
 180 }
 181
 182 #ifdef CONFIG_ZONE_DMA
 183 #define SLUB_DMA __GFP_DMA
 184 #else
 185 /* Disable DMA functionality */
 186 #define SLUB_DMA (__force gfp_t)0
 187 #endif
 188
 189 void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
 190 void *__kmalloc(size_t size, gfp_t flags);
 191
 192 static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
 193 {
 194         return (void *)__get_free_pages(flags | __GFP_COMP, get_order(size));
 195 }
 196
 197 static __always_inline void *kmalloc(size_t size, gfp_t flags)
 198 {
 199         if (__builtin_constant_p(size)) {
 200                 if (size > PAGE_SIZE)
 201                         return kmalloc_large(size, flags);
 202
 203                 if (!(flags & SLUB_DMA)) {
 204                         struct kmem_cache *s = kmalloc_slab(size);
 205
 206                         if (!s)
 207                                 return ZERO_SIZE_PTR;
 208
 209                         return kmem_cache_alloc(s, flags);
 210                 }
 211         }
 212         return __kmalloc(size, flags);
 213 }
 214
 215 #ifdef CONFIG_NUMA
 216 void *__kmalloc_node(size_t size, gfp_t flags, int node);
 217 void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
 218
 219 static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
 220 {
 221         if (__builtin_constant_p(size) &&
 222                 size <= PAGE_SIZE && !(flags & SLUB_DMA)) {
 223                         struct kmem_cache *s = kmalloc_slab(size);
 224
 225                 if (!s)
 226                         return ZERO_SIZE_PTR;
 227
 228                 return kmem_cache_alloc_node(s, flags, node);
 229         }
 230         return __kmalloc_node(size, flags, node);
 231 }
 232 #endif
 233
 234 #endif /* _LINUX_SLUB_DEF_H */