[linux.git] / mm / slab_common.c

/*
 * Slab allocator functions that are independent of the allocator strategy
 *
 * (C) 2012 Christoph Lameter <[email protected]>
 */
#include <linux/slab.h>

#include <linux/mm.h>
#include <linux/poison.h>
#include <linux/interrupt.h>
#include <linux/memory.h>
#include <linux/compiler.h>
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/uaccess.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/page.h>

#include "slab.h"

enum slab_state slab_state;
LIST_HEAD(slab_caches);
DEFINE_MUTEX(slab_mutex);
struct kmem_cache *kmem_cache;

#ifdef CONFIG_DEBUG_VM
static int kmem_cache_sanity_check(const char *name, size_t size)
{
	struct kmem_cache *s = NULL;

	if (!name || in_interrupt() || size < sizeof(void *) ||
		size > KMALLOC_MAX_SIZE) {
		pr_err("kmem_cache_create(%s) integrity check failed\n", name);
		return -EINVAL;
	}

	list_for_each_entry(s, &slab_caches, list) {
		char tmp;
		int res;

		/*
		 * This happens when the module gets unloaded and doesn't
		 * destroy its slab cache and no-one else reuses the vmalloc
		 * area of the module.  Print a warning.
		 */
		res = probe_kernel_address(s->name, tmp);
		if (res) {
			pr_err("Slab cache with size %d has lost its name\n",
			       s->object_size);
			continue;
		}

		if (!strcmp(s->name, name)) {
			pr_err("%s (%s): Cache name already exists.\n",
			       __func__, name);
			dump_stack();
			s = NULL;
			return -EINVAL;
		}
	}

	WARN_ON(strchr(name, ' '));	/* It confuses parsers */
	return 0;
}
#else
static inline int kmem_cache_sanity_check(const char *name, size_t size)
{
	return 0;
}
#endif

/*
 * Figure out what the alignment of the objects will be given a set of
 * flags, a user specified alignment and the size of the objects.
 */
unsigned long calculate_alignment(unsigned long flags,
		unsigned long align, unsigned long size)
{
	/*
	 * If the user wants hardware cache aligned objects then follow that
	 * suggestion if the object is sufficiently large.
	 *
	 * The hardware cache alignment cannot override the specified
	 * alignment though. If that is greater then use it.
	 */
	if (flags & SLAB_HWCACHE_ALIGN) {
		unsigned long ralign = cache_line_size();
		while (size <= ralign / 2)
			ralign /= 2;
		align = max(align, ralign);
	}

	if (align < ARCH_SLAB_MINALIGN)
		align = ARCH_SLAB_MINALIGN;

	return ALIGN(align, sizeof(void *));
}


/*
 * kmem_cache_create - Create a cache.
 * @name: A string which is used in /proc/slabinfo to identify this cache.
 * @size: The size of objects to be created in this cache.
 * @align: The required alignment for the objects.
 * @flags: SLAB flags
 * @ctor: A constructor for the objects.
 *
 * Returns a ptr to the cache on success, NULL on failure.
 * Cannot be called within a interrupt, but can be interrupted.
 * The @ctor is run when new pages are allocated by the cache.
 *
 * The flags are
 *
 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
 * to catch references to uninitialised memory.
 *
 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
 * for buffer overruns.
 *
 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
 * cacheline.  This can be beneficial if you're counting cycles as closely
 * as davem.
 */

struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align,
		unsigned long flags, void (*ctor)(void *))
{
	struct kmem_cache *s = NULL;
	int err = 0;

	get_online_cpus();
	mutex_lock(&slab_mutex);

	if (!kmem_cache_sanity_check(name, size) == 0)
		goto out_locked;

	/*
	 * Some allocators will constraint the set of valid flags to a subset
	 * of all flags. We expect them to define CACHE_CREATE_MASK in this
	 * case, and we'll just provide them with a sanitized version of the
	 * passed flags.
	 */
	flags &= CACHE_CREATE_MASK;

	s = __kmem_cache_alias(name, size, align, flags, ctor);
	if (s)
		goto out_locked;

	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
	if (s) {
		s->object_size = s->size = size;
		s->align = calculate_alignment(flags, align, size);
		s->ctor = ctor;
		s->name = kstrdup(name, GFP_KERNEL);
		if (!s->name) {
			kmem_cache_free(kmem_cache, s);
			err = -ENOMEM;
			goto out_locked;
		}

		err = __kmem_cache_create(s, flags);
		if (!err) {

			s->refcount = 1;
			list_add(&s->list, &slab_caches);

		} else {
			kfree(s->name);
			kmem_cache_free(kmem_cache, s);
		}
	} else
		err = -ENOMEM;

out_locked:
	mutex_unlock(&slab_mutex);
	put_online_cpus();

	if (err) {

		if (flags & SLAB_PANIC)
			panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
				name, err);
		else {
			printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d",
				name, err);
			dump_stack();
		}

		return NULL;
	}

	return s;
}
EXPORT_SYMBOL(kmem_cache_create);

void kmem_cache_destroy(struct kmem_cache *s)
{
	get_online_cpus();
	mutex_lock(&slab_mutex);
	s->refcount--;
	if (!s->refcount) {
		list_del(&s->list);

		if (!__kmem_cache_shutdown(s)) {
			mutex_unlock(&slab_mutex);
			if (s->flags & SLAB_DESTROY_BY_RCU)
				rcu_barrier();

			kfree(s->name);
			kmem_cache_free(kmem_cache, s);
		} else {
			list_add(&s->list, &slab_caches);
			mutex_unlock(&slab_mutex);
			printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",
				s->name);
			dump_stack();
		}
	} else {
		mutex_unlock(&slab_mutex);
	}
	put_online_cpus();
}
EXPORT_SYMBOL(kmem_cache_destroy);

int slab_is_available(void)
{
	return slab_state >= UP;
}

#ifndef CONFIG_SLOB
/* Create a cache during boot when no slab services are available yet */
void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size,
		unsigned long flags)
{
	int err;

	s->name = name;
	s->size = s->object_size = size;
	s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
	err = __kmem_cache_create(s, flags);

	if (err)
		panic("Creation of kmalloc slab %s size=%zd failed. Reason %d\n",
					name, size, err);

	s->refcount = -1;	/* Exempt from merging for now */
}

struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size,
				unsigned long flags)
{
	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);

	if (!s)
		panic("Out of memory when creating slab %s\n", name);

	create_boot_cache(s, name, size, flags);
	list_add(&s->list, &slab_caches);
	s->refcount = 1;
	return s;
}

#endif /* !CONFIG_SLOB */


#ifdef CONFIG_SLABINFO
static void print_slabinfo_header(struct seq_file *m)
{
	/*
	 * Output format version, so at least we can change it
	 * without _too_ many complaints.
	 */
#ifdef CONFIG_DEBUG_SLAB
	seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
#else
	seq_puts(m, "slabinfo - version: 2.1\n");
#endif
	seq_puts(m, "# name            <active_objs> <num_objs> <objsize> "
		 "<objperslab> <pagesperslab>");
	seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
	seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
#ifdef CONFIG_DEBUG_SLAB
	seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
		 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
	seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
#endif
	seq_putc(m, '\n');
}

static void *s_start(struct seq_file *m, loff_t *pos)
{
	loff_t n = *pos;

	mutex_lock(&slab_mutex);
	if (!n)
		print_slabinfo_header(m);

	return seq_list_start(&slab_caches, *pos);
}

static void *s_next(struct seq_file *m, void *p, loff_t *pos)
{
	return seq_list_next(p, &slab_caches, pos);
}

static void s_stop(struct seq_file *m, void *p)
{
	mutex_unlock(&slab_mutex);
}

static int s_show(struct seq_file *m, void *p)
{
	struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
	struct slabinfo sinfo;

	memset(&sinfo, 0, sizeof(sinfo));
	get_slabinfo(s, &sinfo);

	seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
		   s->name, sinfo.active_objs, sinfo.num_objs, s->size,
		   sinfo.objects_per_slab, (1 << sinfo.cache_order));

	seq_printf(m, " : tunables %4u %4u %4u",
		   sinfo.limit, sinfo.batchcount, sinfo.shared);
	seq_printf(m, " : slabdata %6lu %6lu %6lu",
		   sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
	slabinfo_show_stats(m, s);
	seq_putc(m, '\n');
	return 0;
}

/*
 * slabinfo_op - iterator that generates /proc/slabinfo
 *
 * Output layout:
 * cache-name
 * num-active-objs
 * total-objs
 * object size
 * num-active-slabs
 * total-slabs
 * num-pages-per-slab
 * + further values on SMP and with statistics enabled
 */
static const struct seq_operations slabinfo_op = {
	.start = s_start,
	.next = s_next,
	.stop = s_stop,
	.show = s_show,
};

static int slabinfo_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &slabinfo_op);
}

static const struct file_operations proc_slabinfo_operations = {
	.open		= slabinfo_open,
	.read		= seq_read,
	.write          = slabinfo_write,
	.llseek		= seq_lseek,
	.release	= seq_release,
};

static int __init slab_proc_init(void)
{
	proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
	return 0;
}
module_init(slab_proc_init);
#endif /* CONFIG_SLABINFO */
Commit	Line	Data
039363f3 CL	1	/*
	2	* Slab allocator functions that are independent of the allocator strategy
	3	*
	4	* (C) 2012 Christoph Lameter <[email protected]>
	5	*/
	6	#include <linux/slab.h>
	7
	8	#include <linux/mm.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>
20cea968 CL	14	#include <linux/cpu.h>
20cea968 CL	15	#include <linux/uaccess.h>
b7454ad3 GC	16	#include <linux/seq_file.h>
b7454ad3 GC	17	#include <linux/proc_fs.h>
039363f3 CL	18	#include <asm/cacheflush.h>
	19	#include <asm/tlbflush.h>
	20	#include <asm/page.h>
	21
97d06609 CL	22	#include "slab.h"
	23
	24	enum slab_state slab_state;
18004c5d CL	25	LIST_HEAD(slab_caches);
18004c5d CL	26	DEFINE_MUTEX(slab_mutex);
9b030cb8	27	struct kmem_cache *kmem_cache;
97d06609	28
77be4b13 SK	29	#ifdef CONFIG_DEBUG_VM
77be4b13 SK	30	static int kmem_cache_sanity_check(const char *name, size_t size)
039363f3 CL	31	{
	32	struct kmem_cache *s = NULL;
	33
039363f3 CL	34	if (!name \|\| in_interrupt() \|\| size < sizeof(void *) \|\|
039363f3 CL	35	size > KMALLOC_MAX_SIZE) {
77be4b13 SK	36	pr_err("kmem_cache_create(%s) integrity check failed\n", name);
77be4b13 SK	37	return -EINVAL;
039363f3	38	}
b920536a	39
20cea968 CL	40	list_for_each_entry(s, &slab_caches, list) {
	41	char tmp;
	42	int res;
	43
	44	/*
	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.
	48	*/
	49	res = probe_kernel_address(s->name, tmp);
	50	if (res) {
77be4b13	51	pr_err("Slab cache with size %d has lost its name\n",
20cea968 CL	52	s->object_size);
	53	continue;
	54	}
	55
	56	if (!strcmp(s->name, name)) {
77be4b13 SK	57	pr_err("%s (%s): Cache name already exists.\n",
77be4b13 SK	58	__func__, name);
20cea968 CL	59	dump_stack();
20cea968 CL	60	s = NULL;
77be4b13	61	return -EINVAL;
20cea968 CL	62	}
	63	}
	64
	65	WARN_ON(strchr(name, ' ')); /* It confuses parsers */
77be4b13 SK	66	return 0;
	67	}
	68	#else
	69	static inline int kmem_cache_sanity_check(const char *name, size_t size)
	70	{
	71	return 0;
	72	}
20cea968 CL	73	#endif
20cea968 CL	74
45906855 CL	75	/*
	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.
	78	*/
	79	unsigned long calculate_alignment(unsigned long flags,
	80	unsigned long align, unsigned long size)
	81	{
	82	/*
	83	* If the user wants hardware cache aligned objects then follow that
	84	* suggestion if the object is sufficiently large.
	85	*
	86	* The hardware cache alignment cannot override the specified
	87	* alignment though. If that is greater then use it.
	88	*/
	89	if (flags & SLAB_HWCACHE_ALIGN) {
	90	unsigned long ralign = cache_line_size();
	91	while (size <= ralign / 2)
	92	ralign /= 2;
	93	align = max(align, ralign);
	94	}
	95
	96	if (align < ARCH_SLAB_MINALIGN)
	97	align = ARCH_SLAB_MINALIGN;
	98
	99	return ALIGN(align, sizeof(void *));
	100	}
	101
	102
77be4b13 SK	103	/*
	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.
	108	* @flags: SLAB flags
	109	* @ctor: A constructor for the objects.
	110	*
	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.
	114	*
	115	* The flags are
	116	*
	117	* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
	118	* to catch references to uninitialised memory.
	119	*
	120	* %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
	121	* for buffer overruns.
	122	*
	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
	125	* as davem.
	126	*/
	127
	128	struct kmem_cache kmem_cache_create(const char name, size_t size, size_t align,
	129	unsigned long flags, void (ctor)(void ))
	130	{
	131	struct kmem_cache *s = NULL;
686d550d	132	int err = 0;
039363f3	133
77be4b13 SK	134	get_online_cpus();
77be4b13 SK	135	mutex_lock(&slab_mutex);
686d550d CL	136
	137	if (!kmem_cache_sanity_check(name, size) == 0)
	138	goto out_locked;
	139
d8843922 GC	140	/*
	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
	144	* passed flags.
	145	*/
	146	flags &= CACHE_CREATE_MASK;
686d550d	147
cbb79694 CL	148	s = __kmem_cache_alias(name, size, align, flags, ctor);
	149	if (s)
	150	goto out_locked;
	151
278b1bb1	152	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
db265eca	153	if (s) {
8a13a4cc	154	s->object_size = s->size = size;
45906855	155	s->align = calculate_alignment(flags, align, size);
8a13a4cc CL	156	s->ctor = ctor;
	157	s->name = kstrdup(name, GFP_KERNEL);
	158	if (!s->name) {
	159	kmem_cache_free(kmem_cache, s);
	160	err = -ENOMEM;
	161	goto out_locked;
	162	}
	163
	164	err = __kmem_cache_create(s, flags);
cce89f4f	165	if (!err) {
278b1bb1	166
cce89f4f	167	s->refcount = 1;
db265eca	168	list_add(&s->list, &slab_caches);
686d550d	169
cce89f4f	170	} else {
8a13a4cc	171	kfree(s->name);
278b1bb1 CL	172	kmem_cache_free(kmem_cache, s);
278b1bb1 CL	173	}
8a13a4cc	174	} else
278b1bb1	175	err = -ENOMEM;
7c9adf5a	176
686d550d	177	out_locked:
20cea968 CL	178	mutex_unlock(&slab_mutex);
	179	put_online_cpus();
	180
686d550d CL	181	if (err) {
	182
	183	if (flags & SLAB_PANIC)
	184	panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
	185	name, err);
	186	else {
	187	printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d",
	188	name, err);
	189	dump_stack();
	190	}
	191
	192	return NULL;
	193	}
039363f3 CL	194
	195	return s;
	196	}
	197	EXPORT_SYMBOL(kmem_cache_create);
97d06609	198
945cf2b6 CL	199	void kmem_cache_destroy(struct kmem_cache *s)
	200	{
	201	get_online_cpus();
	202	mutex_lock(&slab_mutex);
	203	s->refcount--;
	204	if (!s->refcount) {
	205	list_del(&s->list);
	206
	207	if (!__kmem_cache_shutdown(s)) {
210ed9de	208	mutex_unlock(&slab_mutex);
945cf2b6 CL	209	if (s->flags & SLAB_DESTROY_BY_RCU)
	210	rcu_barrier();
	211
db265eca	212	kfree(s->name);
8f4c765c	213	kmem_cache_free(kmem_cache, s);
945cf2b6 CL	214	} else {
945cf2b6 CL	215	list_add(&s->list, &slab_caches);
210ed9de	216	mutex_unlock(&slab_mutex);
945cf2b6 CL	217	printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",
	218	s->name);
	219	dump_stack();
	220	}
210ed9de JK	221	} else {
210ed9de JK	222	mutex_unlock(&slab_mutex);
945cf2b6	223	}
945cf2b6 CL	224	put_online_cpus();
	225	}
	226	EXPORT_SYMBOL(kmem_cache_destroy);
	227
97d06609 CL	228	int slab_is_available(void)
	229	{
	230	return slab_state >= UP;
	231	}
b7454ad3	232
45530c44 CL	233	#ifndef CONFIG_SLOB
	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,
	236	unsigned long flags)
	237	{
	238	int err;
	239
	240	s->name = name;
	241	s->size = s->object_size = size;
45906855	242	s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
45530c44 CL	243	err = __kmem_cache_create(s, flags);
	244
	245	if (err)
	246	panic("Creation of kmalloc slab %s size=%zd failed. Reason %d\n",
	247	name, size, err);
	248
	249	s->refcount = -1; /* Exempt from merging for now */
	250	}
	251
	252	struct kmem_cache __init create_kmalloc_cache(const char name, size_t size,
	253	unsigned long flags)
	254	{
	255	struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
	256
	257	if (!s)
	258	panic("Out of memory when creating slab %s\n", name);
	259
	260	create_boot_cache(s, name, size, flags);
	261	list_add(&s->list, &slab_caches);
	262	s->refcount = 1;
	263	return s;
	264	}
	265
	266	#endif /* !CONFIG_SLOB */
	267
	268
b7454ad3	269	#ifdef CONFIG_SLABINFO
bcee6e2a GC	270	static void print_slabinfo_header(struct seq_file *m)
	271	{
	272	/*
	273	* Output format version, so at least we can change it
	274	* without _too_ many complaints.
	275	*/
	276	#ifdef CONFIG_DEBUG_SLAB
	277	seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
	278	#else
	279	seq_puts(m, "slabinfo - version: 2.1\n");
	280	#endif
	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>");
	289	#endif
	290	seq_putc(m, '\n');
	291	}
	292
b7454ad3 GC	293	static void s_start(struct seq_file m, loff_t *pos)
	294	{
	295	loff_t n = *pos;
	296
	297	mutex_lock(&slab_mutex);
	298	if (!n)
	299	print_slabinfo_header(m);
	300
	301	return seq_list_start(&slab_caches, *pos);
	302	}
	303
	304	static void s_next(struct seq_file m, void p, loff_t pos)
	305	{
	306	return seq_list_next(p, &slab_caches, pos);
	307	}
	308
	309	static void s_stop(struct seq_file m, void p)
	310	{
	311	mutex_unlock(&slab_mutex);
	312	}
	313
	314	static int s_show(struct seq_file m, void p)
	315	{
0d7561c6 GC	316	struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
	317	struct slabinfo sinfo;
	318
	319	memset(&sinfo, 0, sizeof(sinfo));
	320	get_slabinfo(s, &sinfo);
	321
	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));
	325
	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);
	331	seq_putc(m, '\n');
	332	return 0;
b7454ad3 GC	333	}
	334
	335	/*
	336	* slabinfo_op - iterator that generates /proc/slabinfo
	337	*
	338	* Output layout:
	339	* cache-name
	340	* num-active-objs
	341	* total-objs
	342	* object size
	343	* num-active-slabs
	344	* total-slabs
	345	* num-pages-per-slab
	346	* + further values on SMP and with statistics enabled
	347	*/
	348	static const struct seq_operations slabinfo_op = {
	349	.start = s_start,
	350	.next = s_next,
	351	.stop = s_stop,
	352	.show = s_show,
	353	};
	354
	355	static int slabinfo_open(struct inode inode, struct file file)
	356	{
	357	return seq_open(file, &slabinfo_op);
	358	}
	359
	360	static const struct file_operations proc_slabinfo_operations = {
	361	.open = slabinfo_open,
	362	.read = seq_read,
	363	.write = slabinfo_write,
	364	.llseek = seq_lseek,
	365	.release = seq_release,
	366	};
	367
	368	static int __init slab_proc_init(void)
	369	{
	370	proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
	371	return 0;
	372	}
	373	module_init(slab_proc_init);
	374	#endif /* CONFIG_SLABINFO */