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 */