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Christoph Lameter039363f2012-07-06 15:25:10 -05001/*
2 * Slab allocator functions that are independent of the allocator strategy
3 *
4 * (C) 2012 Christoph Lameter <cl@linux.com>
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>
Christoph Lameter20cea962012-07-06 15:25:13 -050014#include <linux/cpu.h>
15#include <linux/uaccess.h>
Glauber Costab7454ad2012-10-19 18:20:25 +040016#include <linux/seq_file.h>
17#include <linux/proc_fs.h>
Christoph Lameter039363f2012-07-06 15:25:10 -050018#include <asm/cacheflush.h>
19#include <asm/tlbflush.h>
20#include <asm/page.h>
21
Christoph Lameter97d06602012-07-06 15:25:11 -050022#include "slab.h"
23
24enum slab_state slab_state;
Christoph Lameter18004c52012-07-06 15:25:12 -050025LIST_HEAD(slab_caches);
26DEFINE_MUTEX(slab_mutex);
Christoph Lameter9b030cb2012-09-05 00:20:33 +000027struct kmem_cache *kmem_cache;
Christoph Lameter97d06602012-07-06 15:25:11 -050028
Shuah Khan77be4b12012-08-16 00:09:46 -070029#ifdef CONFIG_DEBUG_VM
30static int kmem_cache_sanity_check(const char *name, size_t size)
31{
32 struct kmem_cache *s = NULL;
33
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);
37 return -EINVAL;
38 }
39
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) {
51 pr_err("Slab cache with size %d has lost its name\n",
52 s->object_size);
53 continue;
54 }
55
56 if (!strcmp(s->name, name)) {
57 pr_err("%s (%s): Cache name already exists.\n",
58 __func__, name);
59 dump_stack();
60 s = NULL;
61 return -EINVAL;
62 }
63 }
64
65 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
66 return 0;
67}
68#else
69static inline int kmem_cache_sanity_check(const char *name, size_t size)
70{
71 return 0;
72}
73#endif
74
Christoph Lameter039363f2012-07-06 15:25:10 -050075/*
76 * kmem_cache_create - Create a cache.
77 * @name: A string which is used in /proc/slabinfo to identify this cache.
78 * @size: The size of objects to be created in this cache.
79 * @align: The required alignment for the objects.
80 * @flags: SLAB flags
81 * @ctor: A constructor for the objects.
82 *
83 * Returns a ptr to the cache on success, NULL on failure.
84 * Cannot be called within a interrupt, but can be interrupted.
85 * The @ctor is run when new pages are allocated by the cache.
86 *
87 * The flags are
88 *
89 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
90 * to catch references to uninitialised memory.
91 *
92 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
93 * for buffer overruns.
94 *
95 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
96 * cacheline. This can be beneficial if you're counting cycles as closely
97 * as davem.
98 */
99
100struct kmem_cache *kmem_cache_create(const char *name, size_t size, size_t align,
101 unsigned long flags, void (*ctor)(void *))
102{
103 struct kmem_cache *s = NULL;
Christoph Lameter686d5502012-09-05 00:20:33 +0000104 int err = 0;
Christoph Lameter039363f2012-07-06 15:25:10 -0500105
Pekka Enbergb9205362012-08-16 10:12:18 +0300106 get_online_cpus();
107 mutex_lock(&slab_mutex);
Christoph Lameter686d5502012-09-05 00:20:33 +0000108
109 if (!kmem_cache_sanity_check(name, size) == 0)
110 goto out_locked;
111
112
Christoph Lametercbb79692012-09-05 00:18:32 +0000113 s = __kmem_cache_alias(name, size, align, flags, ctor);
114 if (s)
115 goto out_locked;
116
Christoph Lameter278b1bb2012-09-05 00:20:34 +0000117 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
Christoph Lameterdb265ec2012-09-04 23:18:33 +0000118 if (s) {
Christoph Lameter8a13a4c2012-09-04 23:18:33 +0000119 s->object_size = s->size = size;
120 s->align = align;
121 s->ctor = ctor;
122 s->name = kstrdup(name, GFP_KERNEL);
123 if (!s->name) {
124 kmem_cache_free(kmem_cache, s);
125 err = -ENOMEM;
126 goto out_locked;
127 }
128
129 err = __kmem_cache_create(s, flags);
Christoph Lametercce89f42012-09-04 23:38:33 +0000130 if (!err) {
Christoph Lameter278b1bb2012-09-05 00:20:34 +0000131
Christoph Lametercce89f42012-09-04 23:38:33 +0000132 s->refcount = 1;
Christoph Lameterdb265ec2012-09-04 23:18:33 +0000133 list_add(&s->list, &slab_caches);
134
Christoph Lametercce89f42012-09-04 23:38:33 +0000135 } else {
Christoph Lameter8a13a4c2012-09-04 23:18:33 +0000136 kfree(s->name);
Christoph Lameter278b1bb2012-09-05 00:20:34 +0000137 kmem_cache_free(kmem_cache, s);
138 }
Christoph Lameter8a13a4c2012-09-04 23:18:33 +0000139 } else
Christoph Lameter278b1bb2012-09-05 00:20:34 +0000140 err = -ENOMEM;
Christoph Lameter7c9adf52012-09-04 23:38:33 +0000141
Christoph Lameter686d5502012-09-05 00:20:33 +0000142out_locked:
Christoph Lameter20cea962012-07-06 15:25:13 -0500143 mutex_unlock(&slab_mutex);
144 put_online_cpus();
145
Christoph Lameter686d5502012-09-05 00:20:33 +0000146 if (err) {
147
148 if (flags & SLAB_PANIC)
149 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
150 name, err);
151 else {
152 printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d",
153 name, err);
154 dump_stack();
155 }
156
157 return NULL;
158 }
Christoph Lameter039363f2012-07-06 15:25:10 -0500159
160 return s;
161}
162EXPORT_SYMBOL(kmem_cache_create);
Christoph Lameter97d06602012-07-06 15:25:11 -0500163
Christoph Lameter945cf2b2012-09-04 23:18:33 +0000164void kmem_cache_destroy(struct kmem_cache *s)
165{
166 get_online_cpus();
167 mutex_lock(&slab_mutex);
168 s->refcount--;
169 if (!s->refcount) {
170 list_del(&s->list);
171
172 if (!__kmem_cache_shutdown(s)) {
Jiri Kosina210ed9d2012-10-08 09:26:01 +0200173 mutex_unlock(&slab_mutex);
Christoph Lameter945cf2b2012-09-04 23:18:33 +0000174 if (s->flags & SLAB_DESTROY_BY_RCU)
175 rcu_barrier();
176
Christoph Lameterdb265ec2012-09-04 23:18:33 +0000177 kfree(s->name);
Christoph Lameter8f4c7652012-09-05 00:18:32 +0000178 kmem_cache_free(kmem_cache, s);
Christoph Lameter945cf2b2012-09-04 23:18:33 +0000179 } else {
180 list_add(&s->list, &slab_caches);
Jiri Kosina210ed9d2012-10-08 09:26:01 +0200181 mutex_unlock(&slab_mutex);
Christoph Lameter945cf2b2012-09-04 23:18:33 +0000182 printk(KERN_ERR "kmem_cache_destroy %s: Slab cache still has objects\n",
183 s->name);
184 dump_stack();
185 }
Jiri Kosina210ed9d2012-10-08 09:26:01 +0200186 } else {
187 mutex_unlock(&slab_mutex);
Christoph Lameter945cf2b2012-09-04 23:18:33 +0000188 }
Christoph Lameter945cf2b2012-09-04 23:18:33 +0000189 put_online_cpus();
190}
191EXPORT_SYMBOL(kmem_cache_destroy);
192
Christoph Lameter97d06602012-07-06 15:25:11 -0500193int slab_is_available(void)
194{
195 return slab_state >= UP;
196}
Glauber Costab7454ad2012-10-19 18:20:25 +0400197
198#ifdef CONFIG_SLABINFO
Glauber Costabcee6e22012-10-19 18:20:26 +0400199static void print_slabinfo_header(struct seq_file *m)
200{
201 /*
202 * Output format version, so at least we can change it
203 * without _too_ many complaints.
204 */
205#ifdef CONFIG_DEBUG_SLAB
206 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
207#else
208 seq_puts(m, "slabinfo - version: 2.1\n");
209#endif
210 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
211 "<objperslab> <pagesperslab>");
212 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
213 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
214#ifdef CONFIG_DEBUG_SLAB
215 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
216 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
217 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
218#endif
219 seq_putc(m, '\n');
220}
221
Glauber Costab7454ad2012-10-19 18:20:25 +0400222static void *s_start(struct seq_file *m, loff_t *pos)
223{
224 loff_t n = *pos;
225
226 mutex_lock(&slab_mutex);
227 if (!n)
228 print_slabinfo_header(m);
229
230 return seq_list_start(&slab_caches, *pos);
231}
232
233static void *s_next(struct seq_file *m, void *p, loff_t *pos)
234{
235 return seq_list_next(p, &slab_caches, pos);
236}
237
238static void s_stop(struct seq_file *m, void *p)
239{
240 mutex_unlock(&slab_mutex);
241}
242
243static int s_show(struct seq_file *m, void *p)
244{
245 return slabinfo_show(m, p);
246}
247
248/*
249 * slabinfo_op - iterator that generates /proc/slabinfo
250 *
251 * Output layout:
252 * cache-name
253 * num-active-objs
254 * total-objs
255 * object size
256 * num-active-slabs
257 * total-slabs
258 * num-pages-per-slab
259 * + further values on SMP and with statistics enabled
260 */
261static const struct seq_operations slabinfo_op = {
262 .start = s_start,
263 .next = s_next,
264 .stop = s_stop,
265 .show = s_show,
266};
267
268static int slabinfo_open(struct inode *inode, struct file *file)
269{
270 return seq_open(file, &slabinfo_op);
271}
272
273static const struct file_operations proc_slabinfo_operations = {
274 .open = slabinfo_open,
275 .read = seq_read,
276 .write = slabinfo_write,
277 .llseek = seq_lseek,
278 .release = seq_release,
279};
280
281static int __init slab_proc_init(void)
282{
283 proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
284 return 0;
285}
286module_init(slab_proc_init);
287#endif /* CONFIG_SLABINFO */