slub_def.h 8.2 KB
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#ifndef _LINUX_SLUB_DEF_H
#define _LINUX_SLUB_DEF_H

/*
 * SLUB : A Slab allocator without object queues.
 *
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 * (C) 2007 SGI, Christoph Lameter
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 */
#include <linux/types.h>
#include <linux/gfp.h>
#include <linux/workqueue.h>
#include <linux/kobject.h>
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#include <linux/kmemleak.h>
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#include <trace/events/kmem.h>

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enum stat_item {
	ALLOC_FASTPATH,		/* Allocation from cpu slab */
	ALLOC_SLOWPATH,		/* Allocation by getting a new cpu slab */
	FREE_FASTPATH,		/* Free to cpu slub */
	FREE_SLOWPATH,		/* Freeing not to cpu slab */
	FREE_FROZEN,		/* Freeing to frozen slab */
	FREE_ADD_PARTIAL,	/* Freeing moves slab to partial list */
	FREE_REMOVE_PARTIAL,	/* Freeing removes last object */
	ALLOC_FROM_PARTIAL,	/* Cpu slab acquired from partial list */
	ALLOC_SLAB,		/* Cpu slab acquired from page allocator */
	ALLOC_REFILL,		/* Refill cpu slab from slab freelist */
	FREE_SLAB,		/* Slab freed to the page allocator */
	CPUSLAB_FLUSH,		/* Abandoning of the cpu slab */
	DEACTIVATE_FULL,	/* Cpu slab was full when deactivated */
	DEACTIVATE_EMPTY,	/* Cpu slab was empty when deactivated */
	DEACTIVATE_TO_HEAD,	/* Cpu slab was moved to the head of partials */
	DEACTIVATE_TO_TAIL,	/* Cpu slab was moved to the tail of partials */
	DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
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	ORDER_FALLBACK,		/* Number of times fallback was necessary */
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	NR_SLUB_STAT_ITEMS };

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struct kmem_cache_cpu {
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	void **freelist;	/* Pointer to first free per cpu object */
	struct page *page;	/* The slab from which we are allocating */
	int node;		/* The node of the page (or -1 for debug) */
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#ifdef CONFIG_SLUB_STATS
	unsigned stat[NR_SLUB_STAT_ITEMS];
#endif
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};
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struct kmem_cache_node {
	spinlock_t list_lock;	/* Protect partial list and nr_partial */
	unsigned long nr_partial;
	struct list_head partial;
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#ifdef CONFIG_SLUB_DEBUG
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	atomic_long_t nr_slabs;
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	atomic_long_t total_objects;
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	struct list_head full;
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#endif
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};

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/*
 * Word size structure that can be atomically updated or read and that
 * contains both the order and the number of objects that a slab of the
 * given order would contain.
 */
struct kmem_cache_order_objects {
	unsigned long x;
};

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/*
 * Slab cache management.
 */
struct kmem_cache {
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	struct kmem_cache_cpu __percpu *cpu_slab;
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	/* Used for retriving partial slabs etc */
	unsigned long flags;
	int size;		/* The size of an object including meta data */
	int objsize;		/* The size of an object without meta data */
	int offset;		/* Free pointer offset. */
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	struct kmem_cache_order_objects oo;
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	/* Allocation and freeing of slabs */
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	struct kmem_cache_order_objects max;
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	struct kmem_cache_order_objects min;
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	gfp_t allocflags;	/* gfp flags to use on each alloc */
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	int refcount;		/* Refcount for slab cache destroy */
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	void (*ctor)(void *);
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	int inuse;		/* Offset to metadata */
	int align;		/* Alignment */
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	unsigned long min_partial;
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	const char *name;	/* Name (only for display!) */
	struct list_head list;	/* List of slab caches */
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#ifdef CONFIG_SLUB_DEBUG
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	struct kobject kobj;	/* For sysfs */
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#endif
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#ifdef CONFIG_NUMA
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	/*
	 * Defragmentation by allocating from a remote node.
	 */
	int remote_node_defrag_ratio;
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	struct kmem_cache_node *node[MAX_NUMNODES];
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#else
	/* Avoid an extra cache line for UP */
	struct kmem_cache_node local_node;
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#endif
};

/*
 * Kmalloc subsystem.
 */
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#if defined(ARCH_DMA_MINALIGN) && ARCH_DMA_MINALIGN > 8
#define KMALLOC_MIN_SIZE ARCH_DMA_MINALIGN
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#else
#define KMALLOC_MIN_SIZE 8
#endif

#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
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#ifdef ARCH_DMA_MINALIGN
#define ARCH_KMALLOC_MINALIGN ARCH_DMA_MINALIGN
#else
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#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
#endif

#ifndef ARCH_SLAB_MINALIGN
#define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
#endif

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/*
 * Maximum kmalloc object size handled by SLUB. Larger object allocations
 * are passed through to the page allocator. The page allocator "fastpath"
 * is relatively slow so we need this value sufficiently high so that
 * performance critical objects are allocated through the SLUB fastpath.
 *
 * This should be dropped to PAGE_SIZE / 2 once the page allocator
 * "fastpath" becomes competitive with the slab allocator fastpaths.
 */
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#define SLUB_MAX_SIZE (2 * PAGE_SIZE)
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#define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
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#ifdef CONFIG_ZONE_DMA
#define SLUB_DMA __GFP_DMA
#else
/* Disable DMA functionality */
#define SLUB_DMA (__force gfp_t)0
#endif

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/*
 * We keep the general caches in an array of slab caches that are used for
 * 2^x bytes of allocations.
 */
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extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
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/*
 * Sorry that the following has to be that ugly but some versions of GCC
 * have trouble with constant propagation and loops.
 */
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static __always_inline int kmalloc_index(size_t size)
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{
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	if (!size)
		return 0;
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	if (size <= KMALLOC_MIN_SIZE)
		return KMALLOC_SHIFT_LOW;

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	if (KMALLOC_MIN_SIZE <= 32 && size > 64 && size <= 96)
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		return 1;
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	if (KMALLOC_MIN_SIZE <= 64 && size > 128 && size <= 192)
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		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;
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	if (size <=   4 * 1024) return 12;
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/*
 * The following is only needed to support architectures with a larger page
 * size than 4k.
 */
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	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;
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	if (size <= 512 * 1024) return 19;
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	if (size <= 1024 * 1024) return 20;
	if (size <=  2 * 1024 * 1024) return 21;
	return -1;

/*
 * What we really wanted to do and cannot do because of compiler issues is:
 *	int i;
 *	for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
 *		if (size <= (1 << i))
 *			return i;
 */
}

/*
 * Find the slab cache for a given combination of allocation flags and size.
 *
 * This ought to end up with a global pointer to the right cache
 * in kmalloc_caches.
 */
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static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
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{
	int index = kmalloc_index(size);

	if (index == 0)
		return NULL;

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	return kmalloc_caches[index];
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}

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void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
void *__kmalloc(size_t size, gfp_t flags);

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#ifdef CONFIG_TRACING
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extern void *kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags);
#else
static __always_inline void *
kmem_cache_alloc_notrace(struct kmem_cache *s, gfp_t gfpflags)
{
	return kmem_cache_alloc(s, gfpflags);
}
#endif

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static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
{
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	unsigned int order = get_order(size);
	void *ret = (void *) __get_free_pages(flags | __GFP_COMP, order);

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	kmemleak_alloc(ret, size, 1, flags);
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	trace_kmalloc(_THIS_IP_, ret, size, PAGE_SIZE << order, flags);
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	return ret;
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}

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static __always_inline void *kmalloc(size_t size, gfp_t flags)
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{
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	void *ret;

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	if (__builtin_constant_p(size)) {
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		if (size > SLUB_MAX_SIZE)
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			return kmalloc_large(size, flags);
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		if (!(flags & SLUB_DMA)) {
			struct kmem_cache *s = kmalloc_slab(size);

			if (!s)
				return ZERO_SIZE_PTR;
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			ret = kmem_cache_alloc_notrace(s, flags);

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			trace_kmalloc(_THIS_IP_, ret, size, s->size, flags);
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			return ret;
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		}
	}
	return __kmalloc(size, flags);
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}

#ifdef CONFIG_NUMA
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void *__kmalloc_node(size_t size, gfp_t flags, int node);
void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
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#ifdef CONFIG_TRACING
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extern void *kmem_cache_alloc_node_notrace(struct kmem_cache *s,
					   gfp_t gfpflags,
					   int node);
#else
static __always_inline void *
kmem_cache_alloc_node_notrace(struct kmem_cache *s,
			      gfp_t gfpflags,
			      int node)
{
	return kmem_cache_alloc_node(s, gfpflags, node);
}
#endif

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static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
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{
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	void *ret;

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	if (__builtin_constant_p(size) &&
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		size <= SLUB_MAX_SIZE && !(flags & SLUB_DMA)) {
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			struct kmem_cache *s = kmalloc_slab(size);
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		if (!s)
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			return ZERO_SIZE_PTR;
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		ret = kmem_cache_alloc_node_notrace(s, flags, node);

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		trace_kmalloc_node(_THIS_IP_, ret,
				   size, s->size, flags, node);
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		return ret;
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	}
	return __kmalloc_node(size, flags, node);
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}
#endif

#endif /* _LINUX_SLUB_DEF_H */