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[PATCH] Cleanup slab headers / API to allow easy addition of new slab…
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… allocators

This is a response to an earlier discussion on linux-mm about splitting
slab.h components per allocator.  Patch is against 2.6.19-git11.  See
http://marc.theaimsgroup.com/?l=linux-mm&m=116469577431008&w=2

This patch cleans up the slab header definitions.  We define the common
functions of slob and slab in slab.h and put the extra definitions needed
for slab's kmalloc implementations in <linux/slab_def.h>.  In order to get
a greater set of common functions we add several empty functions to slob.c
and also rename slob's kmalloc to __kmalloc.

Slob does not need any special definitions since we introduce a fallback
case.  If there is no need for a slab implementation to provide its own
kmalloc mess^H^H^Hacros then we simply fall back to __kmalloc functions.
That is sufficient for SLOB.

Sort the function in slab.h according to their functionality.  First the
functions operating on struct kmem_cache * then the kmalloc related
functions followed by special debug and fallback definitions.

Also redo a lot of comments.

Signed-off-by: Christoph Lameter <clameter@sgi.com>?
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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Christoph Lameter authored and Linus Torvalds committed Dec 13, 2006
1 parent 872225c commit 2e892f4
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306 changes: 110 additions & 196 deletions include/linux/slab.h
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Original file line number Diff line number Diff line change
@@ -1,7 +1,9 @@
/*
* linux/include/linux/slab.h
* Written by Mark Hemment, 1996.
* (markhe@nextd.demon.co.uk)
* Written by Mark Hemment, 1996 (markhe@nextd.demon.co.uk).
*
* (C) SGI 2006, Christoph Lameter <clameter@sgi.com>
* Cleaned up and restructured to ease the addition of alternative
* implementations of SLAB allocators.
*/

#ifndef _LINUX_SLAB_H
Expand All @@ -10,64 +12,99 @@
#ifdef __KERNEL__

#include <linux/gfp.h>
#include <linux/init.h>
#include <linux/types.h>
#include <asm/page.h> /* kmalloc_sizes.h needs PAGE_SIZE */
#include <asm/cache.h> /* kmalloc_sizes.h needs L1_CACHE_BYTES */
#include <linux/compiler.h>

/* kmem_cache_t exists for legacy reasons and is not used by code in mm */
typedef struct kmem_cache kmem_cache_t __deprecated;

/* flags to pass to kmem_cache_create().
* The first 3 are only valid when the allocator as been build
* SLAB_DEBUG_SUPPORT.
/*
* 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 /* Peform (expensive) checks on free */
#define SLAB_DEBUG_INITIAL 0x00000200UL /* Call constructor (as verifier) */
#define SLAB_RED_ZONE 0x00000400UL /* Red zone objs in a cache */
#define SLAB_POISON 0x00000800UL /* Poison objects */
#define SLAB_HWCACHE_ALIGN 0x00002000UL /* align objs on a h/w cache lines */
#define SLAB_CACHE_DMA 0x00004000UL /* use GFP_DMA memory */
#define SLAB_MUST_HWCACHE_ALIGN 0x00008000UL /* force alignment */
#define SLAB_STORE_USER 0x00010000UL /* store the last owner for bug hunting */
#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* track pages allocated to indicate
what is reclaimable later*/
#define SLAB_PANIC 0x00040000UL /* panic if kmem_cache_create() fails */
#define SLAB_DESTROY_BY_RCU 0x00080000UL /* defer freeing pages to RCU */
#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */
#define SLAB_DEBUG_INITIAL 0x00000200UL /* DEBUG: Call constructor (as verifier) */
#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_MUST_HWCACHE_ALIGN 0x00008000UL /* Force alignment even if debuggin is active */
#define SLAB_STORE_USER 0x00010000UL /* DEBUG: Store the last owner for bug hunting */
#define SLAB_RECLAIM_ACCOUNT 0x00020000UL /* Objects are reclaimable */
#define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
#define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */

/* flags passed to a constructor func */
#define SLAB_CTOR_CONSTRUCTOR 0x001UL /* if not set, then deconstructor */
#define SLAB_CTOR_ATOMIC 0x002UL /* tell constructor it can't sleep */
#define SLAB_CTOR_VERIFY 0x004UL /* tell constructor it's a verify call */
/* Flags passed to a constructor functions */
#define SLAB_CTOR_CONSTRUCTOR 0x001UL /* If not set, then deconstructor */
#define SLAB_CTOR_ATOMIC 0x002UL /* Tell constructor it can't sleep */
#define SLAB_CTOR_VERIFY 0x004UL /* Tell constructor it's a verify call */

#ifndef CONFIG_SLOB

/* prototypes */
extern void __init kmem_cache_init(void);
/*
* struct kmem_cache related prototypes
*/
void __init kmem_cache_init(void);
extern int slab_is_available(void);

extern struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
unsigned long,
void (*)(void *, struct kmem_cache *, unsigned long),
void (*)(void *, struct kmem_cache *, unsigned long));
extern void kmem_cache_destroy(struct kmem_cache *);
extern int kmem_cache_shrink(struct kmem_cache *);
extern void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
extern void *kmem_cache_zalloc(struct kmem_cache *, gfp_t);
extern void kmem_cache_free(struct kmem_cache *, void *);
extern unsigned int kmem_cache_size(struct kmem_cache *);
extern const char *kmem_cache_name(struct kmem_cache *);
void kmem_cache_destroy(struct kmem_cache *);
int kmem_cache_shrink(struct kmem_cache *);
void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
void *kmem_cache_zalloc(struct kmem_cache *, gfp_t);
void kmem_cache_free(struct kmem_cache *, void *);
unsigned int kmem_cache_size(struct kmem_cache *);
const char *kmem_cache_name(struct kmem_cache *);
int kmem_ptr_validate(struct kmem_cache *cachep, void *ptr);

#ifdef CONFIG_NUMA
extern void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
#else
static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
gfp_t flags, int node)
{
return kmem_cache_alloc(cachep, flags);
}
#endif

/*
* Common kmalloc functions provided by all allocators
*/
void *__kmalloc(size_t, gfp_t);
void *__kzalloc(size_t, gfp_t);
void kfree(const void *);
unsigned int ksize(const void *);

/**
* 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.
*/
static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
{
if (n != 0 && size > ULONG_MAX / n)
return NULL;
return __kzalloc(n * size, flags);
}

/* Size description struct for general caches. */
struct cache_sizes {
size_t cs_size;
struct kmem_cache *cs_cachep;
struct kmem_cache *cs_dmacachep;
};
extern struct cache_sizes malloc_sizes[];
/*
* Allocator specific definitions. These are mainly used to establish optimized
* ways to convert kmalloc() calls to kmem_cache_alloc() invocations by selecting
* the appropriate general cache at compile time.
*/
#ifdef CONFIG_SLAB
#include <linux/slab_def.h>
#else

extern void *__kmalloc(size_t, gfp_t);
/*
* Fallback definitions for an allocator not wanting to provide
* its own optimized kmalloc definitions (like SLOB).
*/

#if defined(CONFIG_NUMA) || defined(CONFIG_DEBUG_SLAB)
#error "SLAB fallback definitions not usable for NUMA or Slab debug"
#endif

/**
* kmalloc - allocate memory
Expand Down Expand Up @@ -114,29 +151,22 @@ extern void *__kmalloc(size_t, gfp_t);
*
* %__GFP_REPEAT - If allocation fails initially, try once more before failing.
*/
static inline void *kmalloc(size_t size, gfp_t flags)
void *kmalloc(size_t size, gfp_t flags)
{
if (__builtin_constant_p(size)) {
int i = 0;
#define CACHE(x) \
if (size <= x) \
goto found; \
else \
i++;
#include "kmalloc_sizes.h"
#undef CACHE
{
extern void __you_cannot_kmalloc_that_much(void);
__you_cannot_kmalloc_that_much();
}
found:
return kmem_cache_alloc((flags & GFP_DMA) ?
malloc_sizes[i].cs_dmacachep :
malloc_sizes[i].cs_cachep, flags);
}
return __kmalloc(size, flags);
}

/**
* 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).
*/
void *kzalloc(size_t size, gfp_t flags)
{
return __kzalloc(size, flags);
}
#endif

/*
* kmalloc_track_caller is a special version of kmalloc that records the
* calling function of the routine calling it for slab leak tracking instead
Expand All @@ -145,89 +175,16 @@ static inline void *kmalloc(size_t size, gfp_t flags)
* allocator where we care about the real place the memory allocation
* request comes from.
*/
#ifndef CONFIG_DEBUG_SLAB
#define kmalloc_track_caller(size, flags) \
__kmalloc(size, flags)
#else
#ifdef CONFIG_DEBUG_SLAB
extern void *__kmalloc_track_caller(size_t, gfp_t, void*);
#define kmalloc_track_caller(size, flags) \
__kmalloc_track_caller(size, flags, __builtin_return_address(0))
#endif

extern void *__kzalloc(size_t, gfp_t);

/**
* 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)
{
if (__builtin_constant_p(size)) {
int i = 0;
#define CACHE(x) \
if (size <= x) \
goto found; \
else \
i++;
#include "kmalloc_sizes.h"
#undef CACHE
{
extern void __you_cannot_kzalloc_that_much(void);
__you_cannot_kzalloc_that_much();
}
found:
return kmem_cache_zalloc((flags & GFP_DMA) ?
malloc_sizes[i].cs_dmacachep :
malloc_sizes[i].cs_cachep, flags);
}
return __kzalloc(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.
*/
static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
{
if (n != 0 && size > ULONG_MAX / n)
return NULL;
return kzalloc(n * size, flags);
}

extern void kfree(const void *);
extern unsigned int ksize(const void *);
extern int slab_is_available(void);
#else
#define kmalloc_track_caller(size, flags) \
__kmalloc(size, flags)
#endif /* DEBUG_SLAB */

#ifdef CONFIG_NUMA
extern void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
extern void *__kmalloc_node(size_t size, gfp_t flags, int node);

static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
{
if (__builtin_constant_p(size)) {
int i = 0;
#define CACHE(x) \
if (size <= x) \
goto found; \
else \
i++;
#include "kmalloc_sizes.h"
#undef CACHE
{
extern void __you_cannot_kmalloc_that_much(void);
__you_cannot_kmalloc_that_much();
}
found:
return kmem_cache_alloc_node((flags & GFP_DMA) ?
malloc_sizes[i].cs_dmacachep :
malloc_sizes[i].cs_cachep, flags, node);
}
return __kmalloc_node(size, flags, node);
}

/*
* kmalloc_node_track_caller is a special version of kmalloc_node that
* records the calling function of the routine calling it for slab leak
Expand All @@ -236,70 +193,27 @@ static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
* standard allocator where we care about the real place the memory
* allocation request comes from.
*/
#ifndef CONFIG_DEBUG_SLAB
#define kmalloc_node_track_caller(size, flags, node) \
__kmalloc_node(size, flags, node)
#else
#ifdef CONFIG_DEBUG_SLAB
extern void *__kmalloc_node_track_caller(size_t, gfp_t, int, void *);
#define kmalloc_node_track_caller(size, flags, node) \
__kmalloc_node_track_caller(size, flags, node, \
__builtin_return_address(0))
#else
#define kmalloc_node_track_caller(size, flags, node) \
__kmalloc_node(size, flags, node)
#endif

#else /* CONFIG_NUMA */
static inline void *kmem_cache_alloc_node(struct kmem_cache *cachep,
gfp_t flags, int node)
{
return kmem_cache_alloc(cachep, flags);
}
static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
{
return kmalloc(size, flags);
}

#define kmalloc_node_track_caller(size, flags, node) \
kmalloc_track_caller(size, flags)
#endif

extern int FASTCALL(kmem_cache_reap(int));
extern int FASTCALL(kmem_ptr_validate(struct kmem_cache *cachep, void *ptr));

#else /* CONFIG_SLOB */

/* SLOB allocator routines */

void kmem_cache_init(void);
struct kmem_cache *kmem_cache_create(const char *c, size_t, size_t,
unsigned long,
void (*)(void *, struct kmem_cache *, unsigned long),
void (*)(void *, struct kmem_cache *, unsigned long));
void kmem_cache_destroy(struct kmem_cache *c);
void *kmem_cache_alloc(struct kmem_cache *c, gfp_t flags);
void *kmem_cache_zalloc(struct kmem_cache *, gfp_t);
void kmem_cache_free(struct kmem_cache *c, void *b);
const char *kmem_cache_name(struct kmem_cache *);
void *kmalloc(size_t size, gfp_t flags);
void *__kzalloc(size_t size, gfp_t flags);
void kfree(const void *m);
unsigned int ksize(const void *m);
unsigned int kmem_cache_size(struct kmem_cache *c);

static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
{
return __kzalloc(n * size, flags);
return kmalloc(size, flags);
}

#define kmem_cache_shrink(d) (0)
#define kmem_cache_reap(a)
#define kmem_ptr_validate(a, b) (0)
#define kmem_cache_alloc_node(c, f, n) kmem_cache_alloc(c, f)
#define kmalloc_node(s, f, n) kmalloc(s, f)
#define kzalloc(s, f) __kzalloc(s, f)
#define kmalloc_track_caller kmalloc

#define kmalloc_node_track_caller kmalloc_node

#endif /* CONFIG_SLOB */

#endif /* !CONFIG_NUMA */
#endif /* __KERNEL__ */

#endif /* _LINUX_SLAB_H */

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