1 #ifndef _LINUX_SLUB_DEF_H
2 #define _LINUX_SLUB_DEF_H
5 * SLUB : A Slab allocator without object queues.
7 * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
9 #include <linux/types.h>
10 #include <linux/gfp.h>
11 #include <linux/workqueue.h>
12 #include <linux/kobject.h>
14 struct kmem_cache_node {
15 spinlock_t list_lock; /* Protect partial list and nr_partial */
16 unsigned long nr_partial;
17 atomic_long_t nr_slabs;
18 struct list_head partial;
19 struct list_head full;
23 * Slab cache management.
26 /* Used for retriving partial slabs etc */
28 int size; /* The size of an object including meta data */
29 int objsize; /* The size of an object without meta data */
30 int offset; /* Free pointer offset. */
34 * Avoid an extra cache line for UP, SMP and for the node local to
37 struct kmem_cache_node local_node;
39 /* Allocation and freeing of slabs */
40 int objects; /* Number of objects in slab */
41 int refcount; /* Refcount for slab cache destroy */
42 void (*ctor)(void *, struct kmem_cache *, unsigned long);
43 int inuse; /* Offset to metadata */
44 int align; /* Alignment */
45 const char *name; /* Name (only for display!) */
46 struct list_head list; /* List of slab caches */
47 struct kobject kobj; /* For sysfs */
51 struct kmem_cache_node *node[MAX_NUMNODES];
53 struct page *cpu_slab[NR_CPUS];
59 #define KMALLOC_SHIFT_LOW 3
62 * We keep the general caches in an array of slab caches that are used for
63 * 2^x bytes of allocations.
65 extern struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
68 * Sorry that the following has to be that ugly but some versions of GCC
69 * have trouble with constant propagation and loops.
71 static inline int kmalloc_index(size_t size)
76 if (size > KMALLOC_MAX_SIZE)
79 if (size > 64 && size <= 96)
81 if (size > 128 && size <= 192)
83 if (size <= 8) return 3;
84 if (size <= 16) return 4;
85 if (size <= 32) return 5;
86 if (size <= 64) return 6;
87 if (size <= 128) return 7;
88 if (size <= 256) return 8;
89 if (size <= 512) return 9;
90 if (size <= 1024) return 10;
91 if (size <= 2 * 1024) return 11;
92 if (size <= 4 * 1024) return 12;
93 if (size <= 8 * 1024) return 13;
94 if (size <= 16 * 1024) return 14;
95 if (size <= 32 * 1024) return 15;
96 if (size <= 64 * 1024) return 16;
97 if (size <= 128 * 1024) return 17;
98 if (size <= 256 * 1024) return 18;
99 if (size <= 512 * 1024) return 19;
100 if (size <= 1024 * 1024) return 20;
101 if (size <= 2 * 1024 * 1024) return 21;
102 if (size <= 4 * 1024 * 1024) return 22;
103 if (size <= 8 * 1024 * 1024) return 23;
104 if (size <= 16 * 1024 * 1024) return 24;
105 if (size <= 32 * 1024 * 1024) return 25;
109 * What we really wanted to do and cannot do because of compiler issues is:
111 * for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
112 * if (size <= (1 << i))
118 * Find the slab cache for a given combination of allocation flags and size.
120 * This ought to end up with a global pointer to the right cache
123 static inline struct kmem_cache *kmalloc_slab(size_t size)
125 int index = kmalloc_index(size);
131 * This function only gets expanded if __builtin_constant_p(size), so
132 * testing it here shouldn't be needed. But some versions of gcc need
135 if (__builtin_constant_p(size) && index < 0) {
137 * Generate a link failure. Would be great if we could
138 * do something to stop the compile here.
140 extern void __kmalloc_size_too_large(void);
141 __kmalloc_size_too_large();
143 return &kmalloc_caches[index];
146 #ifdef CONFIG_ZONE_DMA
147 #define SLUB_DMA __GFP_DMA
149 /* Disable DMA functionality */
155 * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests.
157 * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault.
159 * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can.
160 * Both make kfree a no-op.
162 #define ZERO_SIZE_PTR ((void *)16)
165 static inline void *kmalloc(size_t size, gfp_t flags)
167 if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
168 struct kmem_cache *s = kmalloc_slab(size);
171 return ZERO_SIZE_PTR;
173 return kmem_cache_alloc(s, flags);
175 return __kmalloc(size, flags);
178 static inline void *kzalloc(size_t size, gfp_t flags)
180 if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
181 struct kmem_cache *s = kmalloc_slab(size);
184 return ZERO_SIZE_PTR;
186 return kmem_cache_zalloc(s, flags);
188 return __kzalloc(size, flags);
192 extern void *__kmalloc_node(size_t size, gfp_t flags, int node);
194 static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
196 if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
197 struct kmem_cache *s = kmalloc_slab(size);
200 return ZERO_SIZE_PTR;
202 return kmem_cache_alloc_node(s, flags, node);
204 return __kmalloc_node(size, flags, node);
208 #endif /* _LINUX_SLUB_DEF_H */