LCOV - code coverage report
Current view: top level - lkbce/include/linux - slab.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 1 1 100.0 %
Date: 2017-01-25 Functions: 1 1 100.0 %

          Line data    Source code
       1             : /*
       2             :  * Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
       3             :  *
       4             :  * (C) SGI 2006, Christoph Lameter
       5             :  *      Cleaned up and restructured to ease the addition of alternative
       6             :  *      implementations of SLAB allocators.
       7             :  */
       8             : 
       9             : #ifndef _LINUX_SLAB_H
      10             : #define _LINUX_SLAB_H
      11             : 
      12             : #include <linux/gfp.h>
      13             : #include <linux/types.h>
      14             : 
      15             : /*
      16             :  * Flags to pass to kmem_cache_create().
      17             :  * The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
      18             :  */
      19             : #define SLAB_DEBUG_FREE         0x00000100UL    /* DEBUG: Perform (expensive) checks on free */
      20             : #define SLAB_RED_ZONE           0x00000400UL    /* DEBUG: Red zone objs in a cache */
      21             : #define SLAB_POISON             0x00000800UL    /* DEBUG: Poison objects */
      22             : #define SLAB_HWCACHE_ALIGN      0x00002000UL    /* Align objs on cache lines */
      23             : #define SLAB_CACHE_DMA          0x00004000UL    /* Use GFP_DMA memory */
      24             : #define SLAB_STORE_USER         0x00010000UL    /* DEBUG: Store the last owner for bug hunting */
      25             : #define SLAB_PANIC              0x00040000UL    /* Panic if kmem_cache_create() fails */
      26             : /*
      27             :  * SLAB_DESTROY_BY_RCU - **WARNING** READ THIS!
      28             :  *
      29             :  * This delays freeing the SLAB page by a grace period, it does _NOT_
      30             :  * delay object freeing. This means that if you do kmem_cache_free()
      31             :  * that memory location is free to be reused at any time. Thus it may
      32             :  * be possible to see another object there in the same RCU grace period.
      33             :  *
      34             :  * This feature only ensures the memory location backing the object
      35             :  * stays valid, the trick to using this is relying on an independent
      36             :  * object validation pass. Something like:
      37             :  *
      38             :  *  rcu_read_lock()
      39             :  * again:
      40             :  *  obj = lockless_lookup(key);
      41             :  *  if (obj) {
      42             :  *    if (!try_get_ref(obj)) // might fail for free objects
      43             :  *      goto again;
      44             :  *
      45             :  *    if (obj->key != key) { // not the object we expected
      46             :  *      put_ref(obj);
      47             :  *      goto again;
      48             :  *    }
      49             :  *  }
      50             :  *  rcu_read_unlock();
      51             :  *
      52             :  * See also the comment on struct slab_rcu in mm/slab.c.
      53             :  */
      54             : #define SLAB_DESTROY_BY_RCU     0x00080000UL    /* Defer freeing slabs to RCU */
      55             : #define SLAB_MEM_SPREAD         0x00100000UL    /* Spread some memory over cpuset */
      56             : #define SLAB_TRACE              0x00200000UL    /* Trace allocations and frees */
      57             : 
      58             : /* Flag to prevent checks on free */
      59             : #ifdef CONFIG_DEBUG_OBJECTS
      60             : # define SLAB_DEBUG_OBJECTS     0x00400000UL
      61             : #else
      62             : # define SLAB_DEBUG_OBJECTS     0x00000000UL
      63             : #endif
      64             : 
      65             : #define SLAB_NOLEAKTRACE        0x00800000UL    /* Avoid kmemleak tracing */
      66             : 
      67             : /* Don't track use of uninitialized memory */
      68             : #ifdef CONFIG_KMEMCHECK
      69             : # define SLAB_NOTRACK           0x01000000UL
      70             : #else
      71             : # define SLAB_NOTRACK           0x00000000UL
      72             : #endif
      73             : 
      74             : /* The following flags affect the page allocator grouping pages by mobility */
      75             : #define SLAB_RECLAIM_ACCOUNT    0x00020000UL            /* Objects are reclaimable */
      76             : #define SLAB_TEMPORARY          SLAB_RECLAIM_ACCOUNT    /* Objects are short-lived */
      77             : /*
      78             :  * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
      79             :  *
      80             :  * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
      81             :  *
      82             :  * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
      83             :  * Both make kfree a no-op.
      84             :  */
      85             : #define ZERO_SIZE_PTR ((void *)16)
      86             : 
      87             : #define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
      88             :                                 (unsigned long)ZERO_SIZE_PTR)
      89             : 
      90             : /*
      91             :  * struct kmem_cache related prototypes
      92             :  */
      93             : void __init kmem_cache_init(void);
      94             : int slab_is_available(void);
      95             : 
      96             : struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
      97             :                         unsigned long,
      98             :                         void (*)(void *));
      99             : void kmem_cache_destroy(struct kmem_cache *);
     100             : int kmem_cache_shrink(struct kmem_cache *);
     101             : void kmem_cache_free(struct kmem_cache *, void *);
     102             : unsigned int kmem_cache_size(struct kmem_cache *);
     103             : const char *kmem_cache_name(struct kmem_cache *);
     104             : int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr);
     105             : 
     106             : /*
     107             :  * Please use this macro to create slab caches. Simply specify the
     108             :  * name of the structure and maybe some flags that are listed above.
     109             :  *
     110             :  * The alignment of the struct determines object alignment. If you
     111             :  * f.e. add ____cacheline_aligned_in_smp to the struct declaration
     112             :  * then the objects will be properly aligned in SMP configurations.
     113             :  */
     114             : #define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
     115             :                 sizeof(struct __struct), __alignof__(struct __struct),\
     116             :                 (__flags), NULL)
     117             : 
     118             : /*
     119             :  * The largest kmalloc size supported by the slab allocators is
     120             :  * 32 megabyte (2^25) or the maximum allocatable page order if that is
     121             :  * less than 32 MB.
     122             :  *
     123             :  * WARNING: Its not easy to increase this value since the allocators have
     124             :  * to do various tricks to work around compiler limitations in order to
     125             :  * ensure proper constant folding.
     126             :  */
     127             : #define KMALLOC_SHIFT_HIGH      ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
     128             :                                 (MAX_ORDER + PAGE_SHIFT - 1) : 25)
     129             : 
     130             : #define KMALLOC_MAX_SIZE        (1UL << KMALLOC_SHIFT_HIGH)
     131             : #define KMALLOC_MAX_ORDER       (KMALLOC_SHIFT_HIGH - PAGE_SHIFT)
     132             : 
     133             : /*
     134             :  * Common kmalloc functions provided by all allocators
     135             :  */
     136             : void * __must_check __krealloc(const void *, size_t, gfp_t);
     137             : void * __must_check krealloc(const void *, size_t, gfp_t);
     138             : void kfree(const void *);
     139             : void kzfree(const void *);
     140             : size_t ksize(const void *);
     141             : 
     142             : /*
     143             :  * Allocator specific definitions. These are mainly used to establish optimized
     144             :  * ways to convert kmalloc() calls to kmem_cache_alloc() invocations by
     145             :  * selecting the appropriate general cache at compile time.
     146             :  *
     147             :  * Allocators must define at least:
     148             :  *
     149             :  *      kmem_cache_alloc()
     150             :  *      __kmalloc()
     151             :  *      kmalloc()
     152             :  *
     153             :  * Those wishing to support NUMA must also define:
     154             :  *
     155             :  *      kmem_cache_alloc_node()
     156             :  *      kmalloc_node()
     157             :  *
     158             :  * See each allocator definition file for additional comments and
     159             :  * implementation notes.
     160             :  */
     161             : #ifdef CONFIG_SLUB
     162             : #include <linux/slub_def.h>
     163             : #elif defined(CONFIG_SLOB)
     164             : #include <linux/slob_def.h>
     165             : #else
     166             : #include <linux/slab_def.h>
     167             : #endif
     168             : 
     169             : /**
     170             :  * kcalloc - allocate memory for an array. The memory is set to zero.
     171             :  * @n: number of elements.
     172             :  * @size: element size.
     173             :  * @flags: the type of memory to allocate.
     174             :  *
     175             :  * The @flags argument may be one of:
     176             :  *
     177             :  * %GFP_USER - Allocate memory on behalf of user.  May sleep.
     178             :  *
     179             :  * %GFP_KERNEL - Allocate normal kernel ram.  May sleep.
     180             :  *
     181             :  * %GFP_ATOMIC - Allocation will not sleep.  May use emergency pools.
     182             :  *   For example, use this inside interrupt handlers.
     183             :  *
     184             :  * %GFP_HIGHUSER - Allocate pages from high memory.
     185             :  *
     186             :  * %GFP_NOIO - Do not do any I/O at all while trying to get memory.
     187             :  *
     188             :  * %GFP_NOFS - Do not make any fs calls while trying to get memory.
     189             :  *
     190             :  * %GFP_NOWAIT - Allocation will not sleep.
     191             :  *
     192             :  * %GFP_THISNODE - Allocate node-local memory only.
     193             :  *
     194             :  * %GFP_DMA - Allocation suitable for DMA.
     195             :  *   Should only be used for kmalloc() caches. Otherwise, use a
     196             :  *   slab created with SLAB_DMA.
     197             :  *
     198             :  * Also it is possible to set different flags by OR'ing
     199             :  * in one or more of the following additional @flags:
     200             :  *
     201             :  * %__GFP_COLD - Request cache-cold pages instead of
     202             :  *   trying to return cache-warm pages.
     203             :  *
     204             :  * %__GFP_HIGH - This allocation has high priority and may use emergency pools.
     205             :  *
     206             :  * %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
     207             :  *   (think twice before using).
     208             :  *
     209             :  * %__GFP_NORETRY - If memory is not immediately available,
     210             :  *   then give up at once.
     211             :  *
     212             :  * %__GFP_NOWARN - If allocation fails, don't issue any warnings.
     213             :  *
     214             :  * %__GFP_REPEAT - If allocation fails initially, try once more before failing.
     215             :  *
     216             :  * There are other flags available as well, but these are not intended
     217             :  * for general use, and so are not documented here. For a full list of
     218             :  * potential flags, always refer to linux/gfp.h.
     219             :  */
     220             : static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
     221             : {
     222             :         if (size != 0 && n > ULONG_MAX / size)
     223             :                 return NULL;
     224             :         return __kmalloc(n * size, flags | __GFP_ZERO);
     225             : }
     226             : 
     227             : #if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
     228             : /**
     229             :  * kmalloc_node - allocate memory from a specific node
     230             :  * @size: how many bytes of memory are required.
     231             :  * @flags: the type of memory to allocate (see kcalloc).
     232             :  * @node: node to allocate from.
     233             :  *
     234             :  * kmalloc() for non-local nodes, used to allocate from a specific node
     235             :  * if available. Equivalent to kmalloc() in the non-NUMA single-node
     236             :  * case.
     237             :  */
     238             : static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
     239             : {
     240             :         return kmalloc(size, flags);
     241             : }
     242             : 
     243             : static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
     244             : {
     245             :         return __kmalloc(size, flags);
     246             : }
     247             : 
     248             : void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
     249             : 
     250             : static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
     251             :                                         gfp_t flags, int node)
     252             : {
     253             :         return kmem_cache_alloc(cachep, flags);
     254             : }
     255             : #endif /* !CONFIG_NUMA && !CONFIG_SLOB */
     256             : 
     257             : /*
     258             :  * kmalloc_track_caller is a special version of kmalloc that records the
     259             :  * calling function of the routine calling it for slab leak tracking instead
     260             :  * of just the calling function (confusing, eh?).
     261             :  * It's useful when the call to kmalloc comes from a widely-used standard
     262             :  * allocator where we care about the real place the memory allocation
     263             :  * request comes from.
     264             :  */
     265             : #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
     266             : extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
     267             : #define kmalloc_track_caller(size, flags) \
     268             :         __kmalloc_track_caller(size, flags, _RET_IP_)
     269             : #else
     270             : #define kmalloc_track_caller(size, flags) \
     271             :         __kmalloc(size, flags)
     272             : #endif /* DEBUG_SLAB */
     273             : 
     274             : #ifdef CONFIG_NUMA
     275             : /*
     276             :  * kmalloc_node_track_caller is a special version of kmalloc_node that
     277             :  * records the calling function of the routine calling it for slab leak
     278             :  * tracking instead of just the calling function (confusing, eh?).
     279             :  * It's useful when the call to kmalloc_node comes from a widely-used
     280             :  * standard allocator where we care about the real place the memory
     281             :  * allocation request comes from.
     282             :  */
     283             : #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB)
     284             : extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
     285             : #define kmalloc_node_track_caller(size, flags, node) \
     286             :         __kmalloc_node_track_caller(size, flags, node, \
     287             :                         _RET_IP_)
     288             : #else
     289             : #define kmalloc_node_track_caller(size, flags, node) \
     290             :         __kmalloc_node(size, flags, node)
     291             : #endif
     292             : 
     293             : #else /* CONFIG_NUMA */
     294             : 
     295             : #define kmalloc_node_track_caller(size, flags, node) \
     296             :         kmalloc_track_caller(size, flags)
     297             : 
     298             : #endif /* CONFIG_NUMA */
     299             : 
     300             : /*
     301             :  * Shortcuts
     302             :  */
     303             : static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
     304             : {
     305          24 :         return kmem_cache_alloc(k, flags | __GFP_ZERO);
     306             : }
     307             : 
     308             : /**
     309             :  * kzalloc - allocate memory. The memory is set to zero.
     310             :  * @size: how many bytes of memory are required.
     311             :  * @flags: the type of memory to allocate (see kmalloc).
     312             :  */
     313             : static inline void *kzalloc(size_t size, gfp_t flags)
     314             : {
     315             :         return kmalloc(size, flags | __GFP_ZERO);
     316             : }
     317             : 
     318             : /**
     319             :  * kzalloc_node - allocate zeroed memory from a particular memory node.
     320             :  * @size: how many bytes of memory are required.
     321             :  * @flags: the type of memory to allocate (see kmalloc).
     322             :  * @node: memory node from which to allocate
     323             :  */
     324             : static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
     325             : {
     326             :         return kmalloc_node(size, flags | __GFP_ZERO, node);
     327             : }
     328             : 
     329             : void __init kmem_cache_init_late(void);
     330             : 
     331             : #endif  /* _LINUX_SLAB_H */

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