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linux-next/include/linux/slab.h
Michael Opdenacker e7efa615cc slab: add kmalloc() to kernel API documentation 
At the moment, kmalloc() isn't even listed in the kernel API
documentation (DocBook/kernel-api.html after running "make htmldocs").

Another issue is that the documentation for kmalloc_node()
refers to kcalloc()'s documentation to describe its 'flags' parameter,
while kcalloc() refered to kmalloc()'s documentation, which doesn't exist!

This patch is a proposed fix for this. It also removes the documentation
for kmalloc() in include/linux/slob_def.h which isn't included to
generate the documentation anyway. This way, kmalloc() is described
in only one place.

Acked-by: Christoph Lameter <cl@linux.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Michael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
2013-07-07 19:02:59 +03:00

571 lines
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/*
* Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
*
* (C) SGI 2006, Christoph Lameter
* Cleaned up and restructured to ease the addition of alternative
* implementations of SLAB allocators.
*/
#ifndef _LINUX_SLAB_H
#define _LINUX_SLAB_H
#include <linux/gfp.h>
#include <linux/types.h>
#include <linux/workqueue.h>
/*
* Flags to pass to kmem_cache_create().
* The ones marked DEBUG are only valid if CONFIG_SLAB_DEBUG is set.
*/
#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
#define SLAB_RED_ZONE 0x00000400UL /* DEBUG: Red zone objs in a cache */
#define SLAB_POISON 0x00000800UL /* DEBUG: Poison objects */
#define SLAB_HWCACHE_ALIGN 0x00002000UL /* Align objs on cache lines */
#define SLAB_CACHE_DMA 0x00004000UL /* Use GFP_DMA memory */
#define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
#define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
/*
* SLAB_DESTROY_BY_RCU - **WARNING** READ THIS!
*
* This delays freeing the SLAB page by a grace period, it does _NOT_
* delay object freeing. This means that if you do kmem_cache_free()
* that memory location is free to be reused at any time. Thus it may
* be possible to see another object there in the same RCU grace period.
*
* This feature only ensures the memory location backing the object
* stays valid, the trick to using this is relying on an independent
* object validation pass. Something like:
*
* rcu_read_lock()
* again:
* obj = lockless_lookup(key);
* if (obj) {
* if (!try_get_ref(obj)) // might fail for free objects
* goto again;
*
* if (obj->key != key) { // not the object we expected
* put_ref(obj);
* goto again;
* }
* }
* rcu_read_unlock();
*
* See also the comment on struct slab_rcu in mm/slab.c.
*/
#define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
#define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */
/* Flag to prevent checks on free */
#ifdef CONFIG_DEBUG_OBJECTS
# define SLAB_DEBUG_OBJECTS 0x00400000UL
#else
# define SLAB_DEBUG_OBJECTS 0x00000000UL
#endif
#define SLAB_NOLEAKTRACE 0x00800000UL /* Avoid kmemleak tracing */
/* Don't track use of uninitialized memory */
#ifdef CONFIG_KMEMCHECK
# define SLAB_NOTRACK 0x01000000UL
#else
# define SLAB_NOTRACK 0x00000000UL
#endif
#ifdef CONFIG_FAILSLAB
# define SLAB_FAILSLAB 0x02000000UL /* Fault injection mark */
#else
# define SLAB_FAILSLAB 0x00000000UL
#endif
/* The following flags affect the page allocator grouping pages by mobility */
#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
#define SLAB_TEMPORARY SLAB_RECLAIM_ACCOUNT /* Objects are short-lived */
/*
* ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
*
* Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
*
* ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
* Both make kfree a no-op.
*/
#define ZERO_SIZE_PTR ((void *)16)
#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) <= \
(unsigned long)ZERO_SIZE_PTR)
struct mem_cgroup;
/*
* struct kmem_cache related prototypes
*/
void __init kmem_cache_init(void);
int slab_is_available(void);
struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
unsigned long,
void (*)(void *));
struct kmem_cache *
kmem_cache_create_memcg(struct mem_cgroup *, const char *, size_t, size_t,
unsigned long, void (*)(void *), struct kmem_cache *);
void kmem_cache_destroy(struct kmem_cache *);
int kmem_cache_shrink(struct kmem_cache *);
void kmem_cache_free(struct kmem_cache *, void *);
/*
* Please use this macro to create slab caches. Simply specify the
* name of the structure and maybe some flags that are listed above.
*
* The alignment of the struct determines object alignment. If you
* f.e. add ____cacheline_aligned_in_smp to the struct declaration
* then the objects will be properly aligned in SMP configurations.
*/
#define KMEM_CACHE(__struct, __flags) kmem_cache_create(#__struct,\
sizeof(struct __struct), __alignof__(struct __struct),\
(__flags), NULL)
/*
* Common kmalloc functions provided by all allocators
*/
void * __must_check __krealloc(const void *, size_t, gfp_t);
void * __must_check krealloc(const void *, size_t, gfp_t);
void kfree(const void *);
void kzfree(const void *);
size_t ksize(const void *);
/*
* Some archs want to perform DMA into kmalloc caches and need a guaranteed
* alignment larger than the alignment of a 64-bit integer.
* Setting ARCH_KMALLOC_MINALIGN in arch headers allows that.
*/
#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
#define KMALLOC_SHIFT_LOW ilog2(ARCH_DMA_MINALIGN)
#else
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
#endif
#ifdef CONFIG_SLOB
/*
* Common fields provided in kmem_cache by all slab allocators
* This struct is either used directly by the allocator (SLOB)
* or the allocator must include definitions for all fields
* provided in kmem_cache_common in their definition of kmem_cache.
*
* Once we can do anonymous structs (C11 standard) we could put a
* anonymous struct definition in these allocators so that the
* separate allocations in the kmem_cache structure of SLAB and
* SLUB is no longer needed.
*/
struct kmem_cache {
unsigned int object_size;/* The original size of the object */
unsigned int size; /* The aligned/padded/added on size */
unsigned int align; /* Alignment as calculated */
unsigned long flags; /* Active flags on the slab */
const char *name; /* Slab name for sysfs */
int refcount; /* Use counter */
void (*ctor)(void *); /* Called on object slot creation */
struct list_head list; /* List of all slab caches on the system */
};
#endif /* CONFIG_SLOB */
/*
* Kmalloc array related definitions
*/
#ifdef CONFIG_SLAB
/*
* The largest kmalloc size supported by the SLAB allocators is
* 32 megabyte (2^25) or the maximum allocatable page order if that is
* less than 32 MB.
*
* WARNING: Its not easy to increase this value since the allocators have
* to do various tricks to work around compiler limitations in order to
* ensure proper constant folding.
*/
#define KMALLOC_SHIFT_HIGH ((MAX_ORDER + PAGE_SHIFT - 1) <= 25 ? \
(MAX_ORDER + PAGE_SHIFT - 1) : 25)
#define KMALLOC_SHIFT_MAX KMALLOC_SHIFT_HIGH
#ifndef KMALLOC_SHIFT_LOW
#define KMALLOC_SHIFT_LOW 5
#endif
#endif
#ifdef CONFIG_SLUB
/*
* SLUB allocates up to order 2 pages directly and otherwise
* passes the request to the page allocator.
*/
#define KMALLOC_SHIFT_HIGH (PAGE_SHIFT + 1)
#define KMALLOC_SHIFT_MAX (MAX_ORDER + PAGE_SHIFT)
#ifndef KMALLOC_SHIFT_LOW
#define KMALLOC_SHIFT_LOW 3
#endif
#endif
#ifdef CONFIG_SLOB
/*
* SLOB passes all page size and larger requests to the page allocator.
* No kmalloc array is necessary since objects of different sizes can
* be allocated from the same page.
*/
#define KMALLOC_SHIFT_MAX 30
#define KMALLOC_SHIFT_HIGH PAGE_SHIFT
#ifndef KMALLOC_SHIFT_LOW
#define KMALLOC_SHIFT_LOW 3
#endif
#endif
/* Maximum allocatable size */
#define KMALLOC_MAX_SIZE (1UL << KMALLOC_SHIFT_MAX)
/* Maximum size for which we actually use a slab cache */
#define KMALLOC_MAX_CACHE_SIZE (1UL << KMALLOC_SHIFT_HIGH)
/* Maximum order allocatable via the slab allocagtor */
#define KMALLOC_MAX_ORDER (KMALLOC_SHIFT_MAX - PAGE_SHIFT)
/*
* Kmalloc subsystem.
*/
#ifndef KMALLOC_MIN_SIZE
#define KMALLOC_MIN_SIZE (1 << KMALLOC_SHIFT_LOW)
#endif
#ifndef CONFIG_SLOB
extern struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
#ifdef CONFIG_ZONE_DMA
extern struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
#endif
/*
* Figure out which kmalloc slab an allocation of a certain size
* belongs to.
* 0 = zero alloc
* 1 = 65 .. 96 bytes
* 2 = 120 .. 192 bytes
* n = 2^(n-1) .. 2^n -1
*/
static __always_inline int kmalloc_index(size_t size)
{
if (!size)
return 0;
if (size <= KMALLOC_MIN_SIZE)
return KMALLOC_SHIFT_LOW;
if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
return 1;
if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
return 2;
if (size <= 8) return 3;
if (size <= 16) return 4;
if (size <= 32) return 5;
if (size <= 64) return 6;
if (size <= 128) return 7;
if (size <= 256) return 8;
if (size <= 512) return 9;
if (size <= 1024) return 10;
if (size <= 2 * 1024) return 11;
if (size <= 4 * 1024) return 12;
if (size <= 8 * 1024) return 13;
if (size <= 16 * 1024) return 14;
if (size <= 32 * 1024) return 15;
if (size <= 64 * 1024) return 16;
if (size <= 128 * 1024) return 17;
if (size <= 256 * 1024) return 18;
if (size <= 512 * 1024) return 19;
if (size <= 1024 * 1024) return 20;
if (size <= 2 * 1024 * 1024) return 21;
if (size <= 4 * 1024 * 1024) return 22;
if (size <= 8 * 1024 * 1024) return 23;
if (size <= 16 * 1024 * 1024) return 24;
if (size <= 32 * 1024 * 1024) return 25;
if (size <= 64 * 1024 * 1024) return 26;
BUG();
/* Will never be reached. Needed because the compiler may complain */
return -1;
}
#endif /* !CONFIG_SLOB */
#ifdef CONFIG_SLAB
#include <linux/slab_def.h>
#endif
#ifdef CONFIG_SLUB
#include <linux/slub_def.h>
#endif
#ifdef CONFIG_SLOB
#include <linux/slob_def.h>
#endif
/*
* Determine size used for the nth kmalloc cache.
* return size or 0 if a kmalloc cache for that
* size does not exist
*/
static __always_inline int kmalloc_size(int n)
{
#ifndef CONFIG_SLOB
if (n > 2)
return 1 << n;
if (n == 1 && KMALLOC_MIN_SIZE <= 32)
return 96;
if (n == 2 && KMALLOC_MIN_SIZE <= 64)
return 192;
#endif
return 0;
}
/*
* Setting ARCH_SLAB_MINALIGN in arch headers allows a different alignment.
* Intended for arches that get misalignment faults even for 64 bit integer
* aligned buffers.
*/
#ifndef ARCH_SLAB_MINALIGN
#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
#endif
/*
* This is the main placeholder for memcg-related information in kmem caches.
* struct kmem_cache will hold a pointer to it, so the memory cost while
* disabled is 1 pointer. The runtime cost while enabled, gets bigger than it
* would otherwise be if that would be bundled in kmem_cache: we'll need an
* extra pointer chase. But the trade off clearly lays in favor of not
* penalizing non-users.
*
* Both the root cache and the child caches will have it. For the root cache,
* this will hold a dynamically allocated array large enough to hold
* information about the currently limited memcgs in the system.
*
* Child caches will hold extra metadata needed for its operation. Fields are:
*
* @memcg: pointer to the memcg this cache belongs to
* @list: list_head for the list of all caches in this memcg
* @root_cache: pointer to the global, root cache, this cache was derived from
* @dead: set to true after the memcg dies; the cache may still be around.
* @nr_pages: number of pages that belongs to this cache.
* @destroy: worker to be called whenever we are ready, or believe we may be
* ready, to destroy this cache.
*/
struct memcg_cache_params {
bool is_root_cache;
union {
struct kmem_cache *memcg_caches[0];
struct {
struct mem_cgroup *memcg;
struct list_head list;
struct kmem_cache *root_cache;
bool dead;
atomic_t nr_pages;
struct work_struct destroy;
};
};
};
int memcg_update_all_caches(int num_memcgs);
struct seq_file;
int cache_show(struct kmem_cache *s, struct seq_file *m);
void print_slabinfo_header(struct seq_file *m);
/**
* kmalloc - allocate memory
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate.
*
* The @flags argument may be one of:
*
* %GFP_USER - Allocate memory on behalf of user. May sleep.
*
* %GFP_KERNEL - Allocate normal kernel ram. May sleep.
*
* %GFP_ATOMIC - Allocation will not sleep. May use emergency pools.
* For example, use this inside interrupt handlers.
*
* %GFP_HIGHUSER - Allocate pages from high memory.
*
* %GFP_NOIO - Do not do any I/O at all while trying to get memory.
*
* %GFP_NOFS - Do not make any fs calls while trying to get memory.
*
* %GFP_NOWAIT - Allocation will not sleep.
*
* %GFP_THISNODE - Allocate node-local memory only.
*
* %GFP_DMA - Allocation suitable for DMA.
* Should only be used for kmalloc() caches. Otherwise, use a
* slab created with SLAB_DMA.
*
* Also it is possible to set different flags by OR'ing
* in one or more of the following additional @flags:
*
* %__GFP_COLD - Request cache-cold pages instead of
* trying to return cache-warm pages.
*
* %__GFP_HIGH - This allocation has high priority and may use emergency pools.
*
* %__GFP_NOFAIL - Indicate that this allocation is in no way allowed to fail
* (think twice before using).
*
* %__GFP_NORETRY - If memory is not immediately available,
* then give up at once.
*
* %__GFP_NOWARN - If allocation fails, don't issue any warnings.
*
* %__GFP_REPEAT - If allocation fails initially, try once more before failing.
*
* There are other flags available as well, but these are not intended
* for general use, and so are not documented here. For a full list of
* potential flags, always refer to linux/gfp.h.
*
* kmalloc is the normal method of allocating memory
* in the kernel.
*/
static __always_inline void *kmalloc(size_t size, gfp_t flags);
/**
* kmalloc_array - allocate memory for an array.
* @n: number of elements.
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)
{
if (size != 0 && n > SIZE_MAX / size)
return NULL;
return __kmalloc(n * size, flags);
}
/**
* kcalloc - allocate memory for an array. The memory is set to zero.
* @n: number of elements.
* @size: element size.
* @flags: the type of memory to allocate (see kmalloc).
*/
static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
{
return kmalloc_array(n, size, flags | __GFP_ZERO);
}
#if !defined(CONFIG_NUMA) && !defined(CONFIG_SLOB)
/**
* kmalloc_node - allocate memory from a specific node
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate (see kmalloc).
* @node: node to allocate from.
*
* kmalloc() for non-local nodes, used to allocate from a specific node
* if available. Equivalent to kmalloc() in the non-NUMA single-node
* case.
*/
static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
{
return kmalloc(size, flags);
}
static inline void *__kmalloc_node(size_t size, gfp_t flags, int node)
{
return __kmalloc(size, flags);
}
void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
gfp_t flags, int node)
{
return kmem_cache_alloc(cachep, flags);
}
#endif /* !CONFIG_NUMA && !CONFIG_SLOB */
/*
* kmalloc_track_caller is a special version of kmalloc that records the
* calling function of the routine calling it for slab leak tracking instead
* of just the calling function (confusing, eh?).
* It's useful when the call to kmalloc comes from a widely-used standard
* allocator where we care about the real place the memory allocation
* request comes from.
*/
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
(defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \
(defined(CONFIG_SLOB) && defined(CONFIG_TRACING))
extern void *__kmalloc_track_caller(size_t, gfp_t, unsigned long);
#define kmalloc_track_caller(size, flags) \
__kmalloc_track_caller(size, flags, _RET_IP_)
#else
#define kmalloc_track_caller(size, flags) \
__kmalloc(size, flags)
#endif /* DEBUG_SLAB */
#ifdef CONFIG_NUMA
/*
* kmalloc_node_track_caller is a special version of kmalloc_node that
* records the calling function of the routine calling it for slab leak
* tracking instead of just the calling function (confusing, eh?).
* It's useful when the call to kmalloc_node comes from a widely-used
* standard allocator where we care about the real place the memory
* allocation request comes from.
*/
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_SLUB) || \
(defined(CONFIG_SLAB) && defined(CONFIG_TRACING)) || \
(defined(CONFIG_SLOB) && defined(CONFIG_TRACING))
extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, unsigned long);
#define kmalloc_node_track_caller(size, flags, node) \
__kmalloc_node_track_caller(size, flags, node, \
_RET_IP_)
#else
#define kmalloc_node_track_caller(size, flags, node) \
__kmalloc_node(size, flags, node)
#endif
#else /* CONFIG_NUMA */
#define kmalloc_node_track_caller(size, flags, node) \
kmalloc_track_caller(size, flags)
#endif /* CONFIG_NUMA */
/*
* Shortcuts
*/
static inline void *kmem_cache_zalloc(struct kmem_cache *k, gfp_t flags)
{
return kmem_cache_alloc(k, flags | __GFP_ZERO);
}
/**
* kzalloc - allocate memory. The memory is set to zero.
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate (see kmalloc).
*/
static inline void *kzalloc(size_t size, gfp_t flags)
{
return kmalloc(size, flags | __GFP_ZERO);
}
/**
* kzalloc_node - allocate zeroed memory from a particular memory node.
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate (see kmalloc).
* @node: memory node from which to allocate
*/
static inline void *kzalloc_node(size_t size, gfp_t flags, int node)
{
return kmalloc_node(size, flags | __GFP_ZERO, node);
}
/*
* Determine the size of a slab object
*/
static inline unsigned int kmem_cache_size(struct kmem_cache *s)
{
return s->object_size;
}
void __init kmem_cache_init_late(void);
#endif /* _LINUX_SLAB_H */
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