2 * Slab allocator functions that are independent of the allocator strategy
4 * (C) 2012 Christoph Lameter <cl@linux.com>
6 #include <linux/slab.h>
9 #include <linux/poison.h>
10 #include <linux/interrupt.h>
11 #include <linux/memory.h>
12 #include <linux/compiler.h>
13 #include <linux/module.h>
14 #include <linux/cpu.h>
15 #include <linux/uaccess.h>
16 #include <linux/seq_file.h>
17 #include <linux/proc_fs.h>
18 #include <asm/cacheflush.h>
19 #include <asm/tlbflush.h>
24 enum slab_state slab_state
;
25 LIST_HEAD(slab_caches
);
26 DEFINE_MUTEX(slab_mutex
);
27 struct kmem_cache
*kmem_cache
;
29 #ifdef CONFIG_DEBUG_VM
30 static int kmem_cache_sanity_check(const char *name
, size_t size
)
32 struct kmem_cache
*s
= NULL
;
34 if (!name
|| in_interrupt() || size
< sizeof(void *) ||
35 size
> KMALLOC_MAX_SIZE
) {
36 pr_err("kmem_cache_create(%s) integrity check failed\n", name
);
40 list_for_each_entry(s
, &slab_caches
, list
) {
45 * This happens when the module gets unloaded and doesn't
46 * destroy its slab cache and no-one else reuses the vmalloc
47 * area of the module. Print a warning.
49 res
= probe_kernel_address(s
->name
, tmp
);
51 pr_err("Slab cache with size %d has lost its name\n",
56 if (!strcmp(s
->name
, name
)) {
57 pr_err("%s (%s): Cache name already exists.\n",
65 WARN_ON(strchr(name
, ' ')); /* It confuses parsers */
69 static inline int kmem_cache_sanity_check(const char *name
, size_t size
)
76 * Figure out what the alignment of the objects will be given a set of
77 * flags, a user specified alignment and the size of the objects.
79 unsigned long calculate_alignment(unsigned long flags
,
80 unsigned long align
, unsigned long size
)
83 * If the user wants hardware cache aligned objects then follow that
84 * suggestion if the object is sufficiently large.
86 * The hardware cache alignment cannot override the specified
87 * alignment though. If that is greater then use it.
89 if (flags
& SLAB_HWCACHE_ALIGN
) {
90 unsigned long ralign
= cache_line_size();
91 while (size
<= ralign
/ 2)
93 align
= max(align
, ralign
);
96 if (align
< ARCH_SLAB_MINALIGN
)
97 align
= ARCH_SLAB_MINALIGN
;
99 return ALIGN(align
, sizeof(void *));
104 * kmem_cache_create - Create a cache.
105 * @name: A string which is used in /proc/slabinfo to identify this cache.
106 * @size: The size of objects to be created in this cache.
107 * @align: The required alignment for the objects.
109 * @ctor: A constructor for the objects.
111 * Returns a ptr to the cache on success, NULL on failure.
112 * Cannot be called within a interrupt, but can be interrupted.
113 * The @ctor is run when new pages are allocated by the cache.
117 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
118 * to catch references to uninitialised memory.
120 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
121 * for buffer overruns.
123 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
124 * cacheline. This can be beneficial if you're counting cycles as closely
128 struct kmem_cache
*kmem_cache_create(const char *name
, size_t size
, size_t align
,
129 unsigned long flags
, void (*ctor
)(void *))
131 struct kmem_cache
*s
= NULL
;
135 mutex_lock(&slab_mutex
);
137 if (!kmem_cache_sanity_check(name
, size
) == 0)
141 * Some allocators will constraint the set of valid flags to a subset
142 * of all flags. We expect them to define CACHE_CREATE_MASK in this
143 * case, and we'll just provide them with a sanitized version of the
146 flags
&= CACHE_CREATE_MASK
;
148 s
= __kmem_cache_alias(name
, size
, align
, flags
, ctor
);
152 s
= kmem_cache_zalloc(kmem_cache
, GFP_KERNEL
);
154 s
->object_size
= s
->size
= size
;
155 s
->align
= calculate_alignment(flags
, align
, size
);
157 s
->name
= kstrdup(name
, GFP_KERNEL
);
159 kmem_cache_free(kmem_cache
, s
);
164 err
= __kmem_cache_create(s
, flags
);
168 list_add(&s
->list
, &slab_caches
);
172 kmem_cache_free(kmem_cache
, s
);
178 mutex_unlock(&slab_mutex
);
183 if (flags
& SLAB_PANIC
)
184 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
187 printk(KERN_WARNING
"kmem_cache_create(%s) failed with error %d",
197 EXPORT_SYMBOL(kmem_cache_create
);
199 void kmem_cache_destroy(struct kmem_cache
*s
)
202 mutex_lock(&slab_mutex
);
207 if (!__kmem_cache_shutdown(s
)) {
208 mutex_unlock(&slab_mutex
);
209 if (s
->flags
& SLAB_DESTROY_BY_RCU
)
213 kmem_cache_free(kmem_cache
, s
);
215 list_add(&s
->list
, &slab_caches
);
216 mutex_unlock(&slab_mutex
);
217 printk(KERN_ERR
"kmem_cache_destroy %s: Slab cache still has objects\n",
222 mutex_unlock(&slab_mutex
);
226 EXPORT_SYMBOL(kmem_cache_destroy
);
228 int slab_is_available(void)
230 return slab_state
>= UP
;
234 /* Create a cache during boot when no slab services are available yet */
235 void __init
create_boot_cache(struct kmem_cache
*s
, const char *name
, size_t size
,
241 s
->size
= s
->object_size
= size
;
242 s
->align
= calculate_alignment(flags
, ARCH_KMALLOC_MINALIGN
, size
);
243 err
= __kmem_cache_create(s
, flags
);
246 panic("Creation of kmalloc slab %s size=%zd failed. Reason %d\n",
249 s
->refcount
= -1; /* Exempt from merging for now */
252 struct kmem_cache
*__init
create_kmalloc_cache(const char *name
, size_t size
,
255 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
258 panic("Out of memory when creating slab %s\n", name
);
260 create_boot_cache(s
, name
, size
, flags
);
261 list_add(&s
->list
, &slab_caches
);
266 #endif /* !CONFIG_SLOB */
269 #ifdef CONFIG_SLABINFO
270 static void print_slabinfo_header(struct seq_file
*m
)
273 * Output format version, so at least we can change it
274 * without _too_ many complaints.
276 #ifdef CONFIG_DEBUG_SLAB
277 seq_puts(m
, "slabinfo - version: 2.1 (statistics)\n");
279 seq_puts(m
, "slabinfo - version: 2.1\n");
281 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> "
282 "<objperslab> <pagesperslab>");
283 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
284 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
285 #ifdef CONFIG_DEBUG_SLAB
286 seq_puts(m
, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
287 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
288 seq_puts(m
, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
293 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
297 mutex_lock(&slab_mutex
);
299 print_slabinfo_header(m
);
301 return seq_list_start(&slab_caches
, *pos
);
304 static void *s_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
306 return seq_list_next(p
, &slab_caches
, pos
);
309 static void s_stop(struct seq_file
*m
, void *p
)
311 mutex_unlock(&slab_mutex
);
314 static int s_show(struct seq_file
*m
, void *p
)
316 struct kmem_cache
*s
= list_entry(p
, struct kmem_cache
, list
);
317 struct slabinfo sinfo
;
319 memset(&sinfo
, 0, sizeof(sinfo
));
320 get_slabinfo(s
, &sinfo
);
322 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d",
323 s
->name
, sinfo
.active_objs
, sinfo
.num_objs
, s
->size
,
324 sinfo
.objects_per_slab
, (1 << sinfo
.cache_order
));
326 seq_printf(m
, " : tunables %4u %4u %4u",
327 sinfo
.limit
, sinfo
.batchcount
, sinfo
.shared
);
328 seq_printf(m
, " : slabdata %6lu %6lu %6lu",
329 sinfo
.active_slabs
, sinfo
.num_slabs
, sinfo
.shared_avail
);
330 slabinfo_show_stats(m
, s
);
336 * slabinfo_op - iterator that generates /proc/slabinfo
346 * + further values on SMP and with statistics enabled
348 static const struct seq_operations slabinfo_op
= {
355 static int slabinfo_open(struct inode
*inode
, struct file
*file
)
357 return seq_open(file
, &slabinfo_op
);
360 static const struct file_operations proc_slabinfo_operations
= {
361 .open
= slabinfo_open
,
363 .write
= slabinfo_write
,
365 .release
= seq_release
,
368 static int __init
slab_proc_init(void)
370 proc_create("slabinfo", S_IRUSR
, NULL
, &proc_slabinfo_operations
);
373 module_init(slab_proc_init
);
374 #endif /* CONFIG_SLABINFO */