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
9 #include <linux/types.h>
10 #include <linux/gfp.h>
11 #include <linux/workqueue.h>
12 #include <linux/kobject.h>
15 ALLOC_FASTPATH
, /* Allocation from cpu slab */
16 ALLOC_SLOWPATH
, /* Allocation by getting a new cpu slab */
17 FREE_FASTPATH
, /* Free to cpu slub */
18 FREE_SLOWPATH
, /* Freeing not to cpu slab */
19 FREE_FROZEN
, /* Freeing to frozen slab */
20 FREE_ADD_PARTIAL
, /* Freeing moves slab to partial list */
21 FREE_REMOVE_PARTIAL
, /* Freeing removes last object */
22 ALLOC_FROM_PARTIAL
, /* Cpu slab acquired from partial list */
23 ALLOC_SLAB
, /* Cpu slab acquired from page allocator */
24 ALLOC_REFILL
, /* Refill cpu slab from slab freelist */
25 FREE_SLAB
, /* Slab freed to the page allocator */
26 CPUSLAB_FLUSH
, /* Abandoning of the cpu slab */
27 DEACTIVATE_FULL
, /* Cpu slab was full when deactivated */
28 DEACTIVATE_EMPTY
, /* Cpu slab was empty when deactivated */
29 DEACTIVATE_TO_HEAD
, /* Cpu slab was moved to the head of partials */
30 DEACTIVATE_TO_TAIL
, /* Cpu slab was moved to the tail of partials */
31 DEACTIVATE_REMOTE_FREES
,/* Slab contained remotely freed objects */
32 ORDER_FALLBACK
, /* Number of times fallback was necessary */
35 struct kmem_cache_cpu
{
36 void **freelist
; /* Pointer to first free per cpu object */
37 struct page
*page
; /* The slab from which we are allocating */
38 int node
; /* The node of the page (or -1 for debug) */
39 unsigned int offset
; /* Freepointer offset (in word units) */
40 unsigned int objsize
; /* Size of an object (from kmem_cache) */
41 #ifdef CONFIG_SLUB_STATS
42 unsigned stat
[NR_SLUB_STAT_ITEMS
];
46 struct kmem_cache_node
{
47 spinlock_t list_lock
; /* Protect partial list and nr_partial */
48 unsigned long nr_partial
;
49 struct list_head partial
;
50 #ifdef CONFIG_SLUB_DEBUG
51 atomic_long_t nr_slabs
;
52 atomic_long_t total_objects
;
53 struct list_head full
;
58 * Word size structure that can be atomically updated or read and that
59 * contains both the order and the number of objects that a slab of the
60 * given order would contain.
62 struct kmem_cache_order_objects
{
67 * Slab cache management.
70 /* Used for retriving partial slabs etc */
72 int size
; /* The size of an object including meta data */
73 int objsize
; /* The size of an object without meta data */
74 int offset
; /* Free pointer offset. */
75 struct kmem_cache_order_objects oo
;
78 * Avoid an extra cache line for UP, SMP and for the node local to
81 struct kmem_cache_node local_node
;
83 /* Allocation and freeing of slabs */
84 struct kmem_cache_order_objects max
;
85 struct kmem_cache_order_objects min
;
86 gfp_t allocflags
; /* gfp flags to use on each alloc */
87 int refcount
; /* Refcount for slab cache destroy */
89 int inuse
; /* Offset to metadata */
90 int align
; /* Alignment */
91 unsigned long min_partial
;
92 const char *name
; /* Name (only for display!) */
93 struct list_head list
; /* List of slab caches */
94 #ifdef CONFIG_SLUB_DEBUG
95 struct kobject kobj
; /* For sysfs */
100 * Defragmentation by allocating from a remote node.
102 int remote_node_defrag_ratio
;
103 struct kmem_cache_node
*node
[MAX_NUMNODES
];
106 struct kmem_cache_cpu
*cpu_slab
[NR_CPUS
];
108 struct kmem_cache_cpu cpu_slab
;
115 #if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8
116 #define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN
118 #define KMALLOC_MIN_SIZE 8
121 #define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE)
124 * Maximum kmalloc object size handled by SLUB. Larger object allocations
125 * are passed through to the page allocator. The page allocator "fastpath"
126 * is relatively slow so we need this value sufficiently high so that
127 * performance critical objects are allocated through the SLUB fastpath.
129 * This should be dropped to PAGE_SIZE / 2 once the page allocator
130 * "fastpath" becomes competitive with the slab allocator fastpaths.
132 #define SLUB_MAX_SIZE (2 * PAGE_SIZE)
134 #define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
137 * We keep the general caches in an array of slab caches that are used for
138 * 2^x bytes of allocations.
140 extern struct kmem_cache kmalloc_caches
[SLUB_PAGE_SHIFT
];
143 * Sorry that the following has to be that ugly but some versions of GCC
144 * have trouble with constant propagation and loops.
146 static __always_inline
int kmalloc_index(size_t size
)
151 if (size
<= KMALLOC_MIN_SIZE
)
152 return KMALLOC_SHIFT_LOW
;
154 #if KMALLOC_MIN_SIZE <= 64
155 if (size
> 64 && size
<= 96)
157 if (size
> 128 && size
<= 192)
160 if (size
<= 8) return 3;
161 if (size
<= 16) return 4;
162 if (size
<= 32) return 5;
163 if (size
<= 64) return 6;
164 if (size
<= 128) return 7;
165 if (size
<= 256) return 8;
166 if (size
<= 512) return 9;
167 if (size
<= 1024) return 10;
168 if (size
<= 2 * 1024) return 11;
169 if (size
<= 4 * 1024) return 12;
171 * The following is only needed to support architectures with a larger page
174 if (size
<= 8 * 1024) return 13;
175 if (size
<= 16 * 1024) return 14;
176 if (size
<= 32 * 1024) return 15;
177 if (size
<= 64 * 1024) return 16;
178 if (size
<= 128 * 1024) return 17;
179 if (size
<= 256 * 1024) return 18;
180 if (size
<= 512 * 1024) return 19;
181 if (size
<= 1024 * 1024) return 20;
182 if (size
<= 2 * 1024 * 1024) return 21;
186 * What we really wanted to do and cannot do because of compiler issues is:
188 * for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
189 * if (size <= (1 << i))
195 * Find the slab cache for a given combination of allocation flags and size.
197 * This ought to end up with a global pointer to the right cache
200 static __always_inline
struct kmem_cache
*kmalloc_slab(size_t size
)
202 int index
= kmalloc_index(size
);
207 return &kmalloc_caches
[index
];
210 #ifdef CONFIG_ZONE_DMA
211 #define SLUB_DMA __GFP_DMA
213 /* Disable DMA functionality */
214 #define SLUB_DMA (__force gfp_t)0
217 void *kmem_cache_alloc(struct kmem_cache
*, gfp_t
);
218 void *__kmalloc(size_t size
, gfp_t flags
);
220 static __always_inline
void *kmalloc_large(size_t size
, gfp_t flags
)
222 return (void *)__get_free_pages(flags
| __GFP_COMP
, get_order(size
));
225 static __always_inline
void *kmalloc(size_t size
, gfp_t flags
)
227 if (__builtin_constant_p(size
)) {
228 if (size
> SLUB_MAX_SIZE
)
229 return kmalloc_large(size
, flags
);
231 if (!(flags
& SLUB_DMA
)) {
232 struct kmem_cache
*s
= kmalloc_slab(size
);
235 return ZERO_SIZE_PTR
;
237 return kmem_cache_alloc(s
, flags
);
240 return __kmalloc(size
, flags
);
244 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
);
245 void *kmem_cache_alloc_node(struct kmem_cache
*, gfp_t flags
, int node
);
247 static __always_inline
void *kmalloc_node(size_t size
, gfp_t flags
, int node
)
249 if (__builtin_constant_p(size
) &&
250 size
<= SLUB_MAX_SIZE
&& !(flags
& SLUB_DMA
)) {
251 struct kmem_cache
*s
= kmalloc_slab(size
);
254 return ZERO_SIZE_PTR
;
256 return kmem_cache_alloc_node(s
, flags
, node
);
258 return __kmalloc_node(size
, flags
, node
);
262 #endif /* _LINUX_SLUB_DEF_H */