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>
21 #include <linux/memcontrol.h>
25 enum slab_state slab_state
;
26 LIST_HEAD(slab_caches
);
27 DEFINE_MUTEX(slab_mutex
);
28 struct kmem_cache
*kmem_cache
;
30 #ifdef CONFIG_DEBUG_VM
31 static int kmem_cache_sanity_check(struct mem_cgroup
*memcg
, const char *name
,
34 struct kmem_cache
*s
= NULL
;
36 if (!name
|| in_interrupt() || size
< sizeof(void *) ||
37 size
> KMALLOC_MAX_SIZE
) {
38 pr_err("kmem_cache_create(%s) integrity check failed\n", name
);
42 list_for_each_entry(s
, &slab_caches
, list
) {
47 * This happens when the module gets unloaded and doesn't
48 * destroy its slab cache and no-one else reuses the vmalloc
49 * area of the module. Print a warning.
51 res
= probe_kernel_address(s
->name
, tmp
);
53 pr_err("Slab cache with size %d has lost its name\n",
58 #if !defined(CONFIG_SLUB)
60 * For simplicity, we won't check this in the list of memcg
61 * caches. We have control over memcg naming, and if there
62 * aren't duplicates in the global list, there won't be any
63 * duplicates in the memcg lists as well.
65 if (!memcg
&& !strcmp(s
->name
, name
)) {
66 pr_err("%s (%s): Cache name already exists.\n",
75 WARN_ON(strchr(name
, ' ')); /* It confuses parsers */
79 static inline int kmem_cache_sanity_check(struct mem_cgroup
*memcg
,
80 const char *name
, size_t size
)
86 #ifdef CONFIG_MEMCG_KMEM
87 int memcg_update_all_caches(int num_memcgs
)
91 mutex_lock(&slab_mutex
);
93 list_for_each_entry(s
, &slab_caches
, list
) {
94 if (!is_root_cache(s
))
97 ret
= memcg_update_cache_size(s
, num_memcgs
);
99 * See comment in memcontrol.c, memcg_update_cache_size:
100 * Instead of freeing the memory, we'll just leave the caches
101 * up to this point in an updated state.
107 memcg_update_array_size(num_memcgs
);
109 mutex_unlock(&slab_mutex
);
115 * Figure out what the alignment of the objects will be given a set of
116 * flags, a user specified alignment and the size of the objects.
118 unsigned long calculate_alignment(unsigned long flags
,
119 unsigned long align
, unsigned long size
)
122 * If the user wants hardware cache aligned objects then follow that
123 * suggestion if the object is sufficiently large.
125 * The hardware cache alignment cannot override the specified
126 * alignment though. If that is greater then use it.
128 if (flags
& SLAB_HWCACHE_ALIGN
) {
129 unsigned long ralign
= cache_line_size();
130 while (size
<= ralign
/ 2)
132 align
= max(align
, ralign
);
135 if (align
< ARCH_SLAB_MINALIGN
)
136 align
= ARCH_SLAB_MINALIGN
;
138 return ALIGN(align
, sizeof(void *));
143 * kmem_cache_create - Create a cache.
144 * @name: A string which is used in /proc/slabinfo to identify this cache.
145 * @size: The size of objects to be created in this cache.
146 * @align: The required alignment for the objects.
148 * @ctor: A constructor for the objects.
150 * Returns a ptr to the cache on success, NULL on failure.
151 * Cannot be called within a interrupt, but can be interrupted.
152 * The @ctor is run when new pages are allocated by the cache.
156 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
157 * to catch references to uninitialised memory.
159 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
160 * for buffer overruns.
162 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
163 * cacheline. This can be beneficial if you're counting cycles as closely
168 kmem_cache_create_memcg(struct mem_cgroup
*memcg
, const char *name
, size_t size
,
169 size_t align
, unsigned long flags
, void (*ctor
)(void *),
170 struct kmem_cache
*parent_cache
)
172 struct kmem_cache
*s
= NULL
;
176 mutex_lock(&slab_mutex
);
178 if (!kmem_cache_sanity_check(memcg
, name
, size
) == 0)
182 * Some allocators will constraint the set of valid flags to a subset
183 * of all flags. We expect them to define CACHE_CREATE_MASK in this
184 * case, and we'll just provide them with a sanitized version of the
187 flags
&= CACHE_CREATE_MASK
;
189 s
= __kmem_cache_alias(memcg
, name
, size
, align
, flags
, ctor
);
193 s
= kmem_cache_zalloc(kmem_cache
, GFP_KERNEL
);
195 s
->object_size
= s
->size
= size
;
196 s
->align
= calculate_alignment(flags
, align
, size
);
199 if (memcg_register_cache(memcg
, s
, parent_cache
)) {
200 kmem_cache_free(kmem_cache
, s
);
205 s
->name
= kstrdup(name
, GFP_KERNEL
);
207 kmem_cache_free(kmem_cache
, s
);
212 err
= __kmem_cache_create(s
, flags
);
215 list_add(&s
->list
, &slab_caches
);
216 memcg_cache_list_add(memcg
, s
);
219 kmem_cache_free(kmem_cache
, s
);
225 mutex_unlock(&slab_mutex
);
230 if (flags
& SLAB_PANIC
)
231 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
234 printk(KERN_WARNING
"kmem_cache_create(%s) failed with error %d",
246 kmem_cache_create(const char *name
, size_t size
, size_t align
,
247 unsigned long flags
, void (*ctor
)(void *))
249 return kmem_cache_create_memcg(NULL
, name
, size
, align
, flags
, ctor
, NULL
);
251 EXPORT_SYMBOL(kmem_cache_create
);
253 void kmem_cache_destroy(struct kmem_cache
*s
)
255 /* Destroy all the children caches if we aren't a memcg cache */
256 kmem_cache_destroy_memcg_children(s
);
259 mutex_lock(&slab_mutex
);
264 if (!__kmem_cache_shutdown(s
)) {
265 mutex_unlock(&slab_mutex
);
266 if (s
->flags
& SLAB_DESTROY_BY_RCU
)
269 memcg_release_cache(s
);
271 kmem_cache_free(kmem_cache
, s
);
273 list_add(&s
->list
, &slab_caches
);
274 mutex_unlock(&slab_mutex
);
275 printk(KERN_ERR
"kmem_cache_destroy %s: Slab cache still has objects\n",
280 mutex_unlock(&slab_mutex
);
284 EXPORT_SYMBOL(kmem_cache_destroy
);
286 int slab_is_available(void)
288 return slab_state
>= UP
;
292 /* Create a cache during boot when no slab services are available yet */
293 void __init
create_boot_cache(struct kmem_cache
*s
, const char *name
, size_t size
,
299 s
->size
= s
->object_size
= size
;
300 s
->align
= calculate_alignment(flags
, ARCH_KMALLOC_MINALIGN
, size
);
301 err
= __kmem_cache_create(s
, flags
);
304 panic("Creation of kmalloc slab %s size=%zu failed. Reason %d\n",
307 s
->refcount
= -1; /* Exempt from merging for now */
310 struct kmem_cache
*__init
create_kmalloc_cache(const char *name
, size_t size
,
313 struct kmem_cache
*s
= kmem_cache_zalloc(kmem_cache
, GFP_NOWAIT
);
316 panic("Out of memory when creating slab %s\n", name
);
318 create_boot_cache(s
, name
, size
, flags
);
319 list_add(&s
->list
, &slab_caches
);
324 struct kmem_cache
*kmalloc_caches
[KMALLOC_SHIFT_HIGH
+ 1];
325 EXPORT_SYMBOL(kmalloc_caches
);
327 #ifdef CONFIG_ZONE_DMA
328 struct kmem_cache
*kmalloc_dma_caches
[KMALLOC_SHIFT_HIGH
+ 1];
329 EXPORT_SYMBOL(kmalloc_dma_caches
);
333 * Conversion table for small slabs sizes / 8 to the index in the
334 * kmalloc array. This is necessary for slabs < 192 since we have non power
335 * of two cache sizes there. The size of larger slabs can be determined using
338 static s8 size_index
[24] = {
365 static inline int size_index_elem(size_t bytes
)
367 return (bytes
- 1) / 8;
371 * Find the kmem_cache structure that serves a given size of
374 struct kmem_cache
*kmalloc_slab(size_t size
, gfp_t flags
)
378 if (size
> KMALLOC_MAX_SIZE
) {
379 WARN_ON_ONCE(!(flags
& __GFP_NOWARN
));
385 return ZERO_SIZE_PTR
;
387 index
= size_index
[size_index_elem(size
)];
389 index
= fls(size
- 1);
391 #ifdef CONFIG_ZONE_DMA
392 if (unlikely((flags
& GFP_DMA
)))
393 return kmalloc_dma_caches
[index
];
396 return kmalloc_caches
[index
];
400 * Create the kmalloc array. Some of the regular kmalloc arrays
401 * may already have been created because they were needed to
402 * enable allocations for slab creation.
404 void __init
create_kmalloc_caches(unsigned long flags
)
409 * Patch up the size_index table if we have strange large alignment
410 * requirements for the kmalloc array. This is only the case for
411 * MIPS it seems. The standard arches will not generate any code here.
413 * Largest permitted alignment is 256 bytes due to the way we
414 * handle the index determination for the smaller caches.
416 * Make sure that nothing crazy happens if someone starts tinkering
417 * around with ARCH_KMALLOC_MINALIGN
419 BUILD_BUG_ON(KMALLOC_MIN_SIZE
> 256 ||
420 (KMALLOC_MIN_SIZE
& (KMALLOC_MIN_SIZE
- 1)));
422 for (i
= 8; i
< KMALLOC_MIN_SIZE
; i
+= 8) {
423 int elem
= size_index_elem(i
);
425 if (elem
>= ARRAY_SIZE(size_index
))
427 size_index
[elem
] = KMALLOC_SHIFT_LOW
;
430 if (KMALLOC_MIN_SIZE
>= 64) {
432 * The 96 byte size cache is not used if the alignment
435 for (i
= 64 + 8; i
<= 96; i
+= 8)
436 size_index
[size_index_elem(i
)] = 7;
440 if (KMALLOC_MIN_SIZE
>= 128) {
442 * The 192 byte sized cache is not used if the alignment
443 * is 128 byte. Redirect kmalloc to use the 256 byte cache
446 for (i
= 128 + 8; i
<= 192; i
+= 8)
447 size_index
[size_index_elem(i
)] = 8;
449 for (i
= KMALLOC_SHIFT_LOW
; i
<= KMALLOC_SHIFT_HIGH
; i
++) {
450 if (!kmalloc_caches
[i
]) {
451 kmalloc_caches
[i
] = create_kmalloc_cache(NULL
,
456 * Caches that are not of the two-to-the-power-of size.
457 * These have to be created immediately after the
458 * earlier power of two caches
460 if (KMALLOC_MIN_SIZE
<= 32 && !kmalloc_caches
[1] && i
== 6)
461 kmalloc_caches
[1] = create_kmalloc_cache(NULL
, 96, flags
);
463 if (KMALLOC_MIN_SIZE
<= 64 && !kmalloc_caches
[2] && i
== 7)
464 kmalloc_caches
[2] = create_kmalloc_cache(NULL
, 192, flags
);
467 /* Kmalloc array is now usable */
470 for (i
= 0; i
<= KMALLOC_SHIFT_HIGH
; i
++) {
471 struct kmem_cache
*s
= kmalloc_caches
[i
];
475 n
= kasprintf(GFP_NOWAIT
, "kmalloc-%d", kmalloc_size(i
));
482 #ifdef CONFIG_ZONE_DMA
483 for (i
= 0; i
<= KMALLOC_SHIFT_HIGH
; i
++) {
484 struct kmem_cache
*s
= kmalloc_caches
[i
];
487 int size
= kmalloc_size(i
);
488 char *n
= kasprintf(GFP_NOWAIT
,
489 "dma-kmalloc-%d", size
);
492 kmalloc_dma_caches
[i
] = create_kmalloc_cache(n
,
493 size
, SLAB_CACHE_DMA
| flags
);
498 #endif /* !CONFIG_SLOB */
501 #ifdef CONFIG_SLABINFO
502 void print_slabinfo_header(struct seq_file
*m
)
505 * Output format version, so at least we can change it
506 * without _too_ many complaints.
508 #ifdef CONFIG_DEBUG_SLAB
509 seq_puts(m
, "slabinfo - version: 2.1 (statistics)\n");
511 seq_puts(m
, "slabinfo - version: 2.1\n");
513 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> "
514 "<objperslab> <pagesperslab>");
515 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
516 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
517 #ifdef CONFIG_DEBUG_SLAB
518 seq_puts(m
, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
519 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
520 seq_puts(m
, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
525 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
529 mutex_lock(&slab_mutex
);
531 print_slabinfo_header(m
);
533 return seq_list_start(&slab_caches
, *pos
);
536 static void *s_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
538 return seq_list_next(p
, &slab_caches
, pos
);
541 static void s_stop(struct seq_file
*m
, void *p
)
543 mutex_unlock(&slab_mutex
);
547 memcg_accumulate_slabinfo(struct kmem_cache
*s
, struct slabinfo
*info
)
549 struct kmem_cache
*c
;
550 struct slabinfo sinfo
;
553 if (!is_root_cache(s
))
556 for_each_memcg_cache_index(i
) {
557 c
= cache_from_memcg(s
, i
);
561 memset(&sinfo
, 0, sizeof(sinfo
));
562 get_slabinfo(c
, &sinfo
);
564 info
->active_slabs
+= sinfo
.active_slabs
;
565 info
->num_slabs
+= sinfo
.num_slabs
;
566 info
->shared_avail
+= sinfo
.shared_avail
;
567 info
->active_objs
+= sinfo
.active_objs
;
568 info
->num_objs
+= sinfo
.num_objs
;
572 int cache_show(struct kmem_cache
*s
, struct seq_file
*m
)
574 struct slabinfo sinfo
;
576 memset(&sinfo
, 0, sizeof(sinfo
));
577 get_slabinfo(s
, &sinfo
);
579 memcg_accumulate_slabinfo(s
, &sinfo
);
581 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d",
582 cache_name(s
), sinfo
.active_objs
, sinfo
.num_objs
, s
->size
,
583 sinfo
.objects_per_slab
, (1 << sinfo
.cache_order
));
585 seq_printf(m
, " : tunables %4u %4u %4u",
586 sinfo
.limit
, sinfo
.batchcount
, sinfo
.shared
);
587 seq_printf(m
, " : slabdata %6lu %6lu %6lu",
588 sinfo
.active_slabs
, sinfo
.num_slabs
, sinfo
.shared_avail
);
589 slabinfo_show_stats(m
, s
);
594 static int s_show(struct seq_file
*m
, void *p
)
596 struct kmem_cache
*s
= list_entry(p
, struct kmem_cache
, list
);
598 if (!is_root_cache(s
))
600 return cache_show(s
, m
);
604 * slabinfo_op - iterator that generates /proc/slabinfo
614 * + further values on SMP and with statistics enabled
616 static const struct seq_operations slabinfo_op
= {
623 static int slabinfo_open(struct inode
*inode
, struct file
*file
)
625 return seq_open(file
, &slabinfo_op
);
628 static const struct file_operations proc_slabinfo_operations
= {
629 .open
= slabinfo_open
,
631 .write
= slabinfo_write
,
633 .release
= seq_release
,
636 static int __init
slab_proc_init(void)
638 proc_create("slabinfo", S_IRUSR
, NULL
, &proc_slabinfo_operations
);
641 module_init(slab_proc_init
);
642 #endif /* CONFIG_SLABINFO */