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>
23 #define CREATE_TRACE_POINTS
24 #include <trace/events/kmem.h>
28 enum slab_state slab_state;
29 LIST_HEAD(slab_caches);
30 DEFINE_MUTEX(slab_mutex);
31 struct kmem_cache *kmem_cache;
34 * Set of flags that will prevent slab merging
36 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
37 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
40 #define SLAB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
41 SLAB_CACHE_DMA | SLAB_NOTRACK)
44 * Merge control. If this is set then no merging of slab caches will occur.
45 * (Could be removed. This was introduced to pacify the merge skeptics.)
47 static int slab_nomerge;
49 static int __init setup_slab_nomerge(char *str)
56 __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
59 __setup("slab_nomerge", setup_slab_nomerge);
62 * Determine the size of a slab object
64 unsigned int kmem_cache_size(struct kmem_cache *s)
66 return s->object_size;
68 EXPORT_SYMBOL(kmem_cache_size);
70 #ifdef CONFIG_DEBUG_VM
71 static int kmem_cache_sanity_check(const char *name, size_t size)
73 struct kmem_cache *s = NULL;
75 if (!name || in_interrupt() || size < sizeof(void *) ||
76 size > KMALLOC_MAX_SIZE) {
77 pr_err("kmem_cache_create(%s) integrity check failed\n", name);
81 list_for_each_entry(s, &slab_caches, list) {
86 * This happens when the module gets unloaded and doesn't
87 * destroy its slab cache and no-one else reuses the vmalloc
88 * area of the module. Print a warning.
90 res = probe_kernel_address(s->name, tmp);
92 pr_err("Slab cache with size %d has lost its name\n",
98 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
102 static inline int kmem_cache_sanity_check(const char *name, size_t size)
108 #ifdef CONFIG_MEMCG_KMEM
109 void slab_init_memcg_params(struct kmem_cache *s)
111 s->memcg_params.is_root_cache = true;
112 INIT_LIST_HEAD(&s->memcg_params.list);
113 RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL);
116 static int init_memcg_params(struct kmem_cache *s,
117 struct mem_cgroup *memcg, struct kmem_cache *root_cache)
119 struct memcg_cache_array *arr;
122 s->memcg_params.is_root_cache = false;
123 s->memcg_params.memcg = memcg;
124 s->memcg_params.root_cache = root_cache;
128 slab_init_memcg_params(s);
130 if (!memcg_nr_cache_ids)
133 arr = kzalloc(sizeof(struct memcg_cache_array) +
134 memcg_nr_cache_ids * sizeof(void *),
139 RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr);
143 static void destroy_memcg_params(struct kmem_cache *s)
145 if (is_root_cache(s))
146 kfree(rcu_access_pointer(s->memcg_params.memcg_caches));
149 static int update_memcg_params(struct kmem_cache *s, int new_array_size)
151 struct memcg_cache_array *old, *new;
153 if (!is_root_cache(s))
156 new = kzalloc(sizeof(struct memcg_cache_array) +
157 new_array_size * sizeof(void *), GFP_KERNEL);
161 old = rcu_dereference_protected(s->memcg_params.memcg_caches,
162 lockdep_is_held(&slab_mutex));
164 memcpy(new->entries, old->entries,
165 memcg_nr_cache_ids * sizeof(void *));
167 rcu_assign_pointer(s->memcg_params.memcg_caches, new);
173 int memcg_update_all_caches(int num_memcgs)
175 struct kmem_cache *s;
178 mutex_lock(&slab_mutex);
179 list_for_each_entry(s, &slab_caches, list) {
180 ret = update_memcg_params(s, num_memcgs);
182 * Instead of freeing the memory, we'll just leave the caches
183 * up to this point in an updated state.
188 mutex_unlock(&slab_mutex);
192 static inline int init_memcg_params(struct kmem_cache *s,
193 struct mem_cgroup *memcg, struct kmem_cache *root_cache)
198 static inline void destroy_memcg_params(struct kmem_cache *s)
201 #endif /* CONFIG_MEMCG_KMEM */
204 * Find a mergeable slab cache
206 int slab_unmergeable(struct kmem_cache *s)
208 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
211 if (!is_root_cache(s))
218 * We may have set a slab to be unmergeable during bootstrap.
226 struct kmem_cache *find_mergeable(size_t size, size_t align,
227 unsigned long flags, const char *name, void (*ctor)(void *))
229 struct kmem_cache *s;
231 if (slab_nomerge || (flags & SLAB_NEVER_MERGE))
237 size = ALIGN(size, sizeof(void *));
238 align = calculate_alignment(flags, align, size);
239 size = ALIGN(size, align);
240 flags = kmem_cache_flags(size, flags, name, NULL);
242 list_for_each_entry_reverse(s, &slab_caches, list) {
243 if (slab_unmergeable(s))
249 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
252 * Check if alignment is compatible.
253 * Courtesy of Adrian Drzewiecki
255 if ((s->size & ~(align - 1)) != s->size)
258 if (s->size - size >= sizeof(void *))
261 if (IS_ENABLED(CONFIG_SLAB) && align &&
262 (align > s->align || s->align % align))
271 * Figure out what the alignment of the objects will be given a set of
272 * flags, a user specified alignment and the size of the objects.
274 unsigned long calculate_alignment(unsigned long flags,
275 unsigned long align, unsigned long size)
278 * If the user wants hardware cache aligned objects then follow that
279 * suggestion if the object is sufficiently large.
281 * The hardware cache alignment cannot override the specified
282 * alignment though. If that is greater then use it.
284 if (flags & SLAB_HWCACHE_ALIGN) {
285 unsigned long ralign = cache_line_size();
286 while (size <= ralign / 2)
288 align = max(align, ralign);
291 if (align < ARCH_SLAB_MINALIGN)
292 align = ARCH_SLAB_MINALIGN;
294 return ALIGN(align, sizeof(void *));
297 static struct kmem_cache *
298 do_kmem_cache_create(char *name, size_t object_size, size_t size, size_t align,
299 unsigned long flags, void (*ctor)(void *),
300 struct mem_cgroup *memcg, struct kmem_cache *root_cache)
302 struct kmem_cache *s;
306 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
311 s->object_size = object_size;
316 err = init_memcg_params(s, memcg, root_cache);
320 err = __kmem_cache_create(s, flags);
325 list_add(&s->list, &slab_caches);
332 destroy_memcg_params(s);
333 kmem_cache_free(kmem_cache, s);
338 * kmem_cache_create - Create a cache.
339 * @name: A string which is used in /proc/slabinfo to identify this cache.
340 * @size: The size of objects to be created in this cache.
341 * @align: The required alignment for the objects.
343 * @ctor: A constructor for the objects.
345 * Returns a ptr to the cache on success, NULL on failure.
346 * Cannot be called within a interrupt, but can be interrupted.
347 * The @ctor is run when new pages are allocated by the cache.
351 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
352 * to catch references to uninitialised memory.
354 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
355 * for buffer overruns.
357 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
358 * cacheline. This can be beneficial if you're counting cycles as closely
362 kmem_cache_create(const char *name, size_t size, size_t align,
363 unsigned long flags, void (*ctor)(void *))
365 struct kmem_cache *s;
371 memcg_get_cache_ids();
373 mutex_lock(&slab_mutex);
375 err = kmem_cache_sanity_check(name, size);
377 s = NULL; /* suppress uninit var warning */
382 * Some allocators will constraint the set of valid flags to a subset
383 * of all flags. We expect them to define CACHE_CREATE_MASK in this
384 * case, and we'll just provide them with a sanitized version of the
387 flags &= CACHE_CREATE_MASK;
389 s = __kmem_cache_alias(name, size, align, flags, ctor);
393 cache_name = kstrdup(name, GFP_KERNEL);
399 s = do_kmem_cache_create(cache_name, size, size,
400 calculate_alignment(flags, align, size),
401 flags, ctor, NULL, NULL);
408 mutex_unlock(&slab_mutex);
410 memcg_put_cache_ids();
415 if (flags & SLAB_PANIC)
416 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
419 printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d",
427 EXPORT_SYMBOL(kmem_cache_create);
429 static int do_kmem_cache_shutdown(struct kmem_cache *s,
430 struct list_head *release, bool *need_rcu_barrier)
432 if (__kmem_cache_shutdown(s) != 0) {
433 printk(KERN_ERR "kmem_cache_destroy %s: "
434 "Slab cache still has objects\n", s->name);
439 if (s->flags & SLAB_DESTROY_BY_RCU)
440 *need_rcu_barrier = true;
442 #ifdef CONFIG_MEMCG_KMEM
443 if (!is_root_cache(s)) {
445 struct memcg_cache_array *arr;
447 idx = memcg_cache_id(s->memcg_params.memcg);
448 arr = rcu_dereference_protected(s->memcg_params.root_cache->
449 memcg_params.memcg_caches,
450 lockdep_is_held(&slab_mutex));
451 BUG_ON(arr->entries[idx] != s);
452 arr->entries[idx] = NULL;
453 list_del(&s->memcg_params.list);
456 list_move(&s->list, release);
460 static void do_kmem_cache_release(struct list_head *release,
461 bool need_rcu_barrier)
463 struct kmem_cache *s, *s2;
465 if (need_rcu_barrier)
468 list_for_each_entry_safe(s, s2, release, list) {
469 #ifdef SLAB_SUPPORTS_SYSFS
470 sysfs_slab_remove(s);
472 slab_kmem_cache_release(s);
477 #ifdef CONFIG_MEMCG_KMEM
479 * memcg_create_kmem_cache - Create a cache for a memory cgroup.
480 * @memcg: The memory cgroup the new cache is for.
481 * @root_cache: The parent of the new cache.
483 * This function attempts to create a kmem cache that will serve allocation
484 * requests going from @memcg to @root_cache. The new cache inherits properties
487 void memcg_create_kmem_cache(struct mem_cgroup *memcg,
488 struct kmem_cache *root_cache)
490 static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */
491 struct memcg_cache_array *arr;
492 struct kmem_cache *s = NULL;
499 mutex_lock(&slab_mutex);
501 idx = memcg_cache_id(memcg);
502 arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches,
503 lockdep_is_held(&slab_mutex));
506 * Since per-memcg caches are created asynchronously on first
507 * allocation (see memcg_kmem_get_cache()), several threads can try to
508 * create the same cache, but only one of them may succeed.
510 if (arr->entries[idx])
513 cgroup_name(mem_cgroup_css(memcg)->cgroup,
514 memcg_name_buf, sizeof(memcg_name_buf));
515 cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name,
516 idx, memcg_name_buf);
520 s = do_kmem_cache_create(cache_name, root_cache->object_size,
521 root_cache->size, root_cache->align,
522 root_cache->flags, root_cache->ctor,
525 * If we could not create a memcg cache, do not complain, because
526 * that's not critical at all as we can always proceed with the root
534 list_add(&s->memcg_params.list, &root_cache->memcg_params.list);
537 * Since readers won't lock (see cache_from_memcg_idx()), we need a
538 * barrier here to ensure nobody will see the kmem_cache partially
542 arr->entries[idx] = s;
545 mutex_unlock(&slab_mutex);
551 void memcg_destroy_kmem_caches(struct mem_cgroup *memcg)
554 bool need_rcu_barrier = false;
555 struct kmem_cache *s, *s2;
560 mutex_lock(&slab_mutex);
561 list_for_each_entry_safe(s, s2, &slab_caches, list) {
562 if (is_root_cache(s) || s->memcg_params.memcg != memcg)
565 * The cgroup is about to be freed and therefore has no charges
566 * left. Hence, all its caches must be empty by now.
568 BUG_ON(do_kmem_cache_shutdown(s, &release, &need_rcu_barrier));
570 mutex_unlock(&slab_mutex);
575 do_kmem_cache_release(&release, need_rcu_barrier);
577 #endif /* CONFIG_MEMCG_KMEM */
579 void slab_kmem_cache_release(struct kmem_cache *s)
581 destroy_memcg_params(s);
583 kmem_cache_free(kmem_cache, s);
586 void kmem_cache_destroy(struct kmem_cache *s)
588 struct kmem_cache *c, *c2;
590 bool need_rcu_barrier = false;
593 BUG_ON(!is_root_cache(s));
598 mutex_lock(&slab_mutex);
604 for_each_memcg_cache_safe(c, c2, s) {
605 if (do_kmem_cache_shutdown(c, &release, &need_rcu_barrier))
610 do_kmem_cache_shutdown(s, &release, &need_rcu_barrier);
613 mutex_unlock(&slab_mutex);
618 do_kmem_cache_release(&release, need_rcu_barrier);
620 EXPORT_SYMBOL(kmem_cache_destroy);
623 * kmem_cache_shrink - Shrink a cache.
624 * @cachep: The cache to shrink.
626 * Releases as many slabs as possible for a cache.
627 * To help debugging, a zero exit status indicates all slabs were released.
629 int kmem_cache_shrink(struct kmem_cache *cachep)
635 ret = __kmem_cache_shrink(cachep);
640 EXPORT_SYMBOL(kmem_cache_shrink);
642 int slab_is_available(void)
644 return slab_state >= UP;
648 /* Create a cache during boot when no slab services are available yet */
649 void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size,
655 s->size = s->object_size = size;
656 s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size);
658 slab_init_memcg_params(s);
660 err = __kmem_cache_create(s, flags);
663 panic("Creation of kmalloc slab %s size=%zu failed. Reason %d\n",
666 s->refcount = -1; /* Exempt from merging for now */
669 struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size,
672 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
675 panic("Out of memory when creating slab %s\n", name);
677 create_boot_cache(s, name, size, flags);
678 list_add(&s->list, &slab_caches);
683 struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1];
684 EXPORT_SYMBOL(kmalloc_caches);
686 #ifdef CONFIG_ZONE_DMA
687 struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1];
688 EXPORT_SYMBOL(kmalloc_dma_caches);
692 * Conversion table for small slabs sizes / 8 to the index in the
693 * kmalloc array. This is necessary for slabs < 192 since we have non power
694 * of two cache sizes there. The size of larger slabs can be determined using
697 static s8 size_index[24] = {
724 static inline int size_index_elem(size_t bytes)
726 return (bytes - 1) / 8;
730 * Find the kmem_cache structure that serves a given size of
733 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
737 if (unlikely(size > KMALLOC_MAX_SIZE)) {
738 WARN_ON_ONCE(!(flags & __GFP_NOWARN));
744 return ZERO_SIZE_PTR;
746 index = size_index[size_index_elem(size)];
748 index = fls(size - 1);
750 #ifdef CONFIG_ZONE_DMA
751 if (unlikely((flags & GFP_DMA)))
752 return kmalloc_dma_caches[index];
755 return kmalloc_caches[index];
759 * Create the kmalloc array. Some of the regular kmalloc arrays
760 * may already have been created because they were needed to
761 * enable allocations for slab creation.
763 void __init create_kmalloc_caches(unsigned long flags)
768 * Patch up the size_index table if we have strange large alignment
769 * requirements for the kmalloc array. This is only the case for
770 * MIPS it seems. The standard arches will not generate any code here.
772 * Largest permitted alignment is 256 bytes due to the way we
773 * handle the index determination for the smaller caches.
775 * Make sure that nothing crazy happens if someone starts tinkering
776 * around with ARCH_KMALLOC_MINALIGN
778 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
779 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
781 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
782 int elem = size_index_elem(i);
784 if (elem >= ARRAY_SIZE(size_index))
786 size_index[elem] = KMALLOC_SHIFT_LOW;
789 if (KMALLOC_MIN_SIZE >= 64) {
791 * The 96 byte size cache is not used if the alignment
794 for (i = 64 + 8; i <= 96; i += 8)
795 size_index[size_index_elem(i)] = 7;
799 if (KMALLOC_MIN_SIZE >= 128) {
801 * The 192 byte sized cache is not used if the alignment
802 * is 128 byte. Redirect kmalloc to use the 256 byte cache
805 for (i = 128 + 8; i <= 192; i += 8)
806 size_index[size_index_elem(i)] = 8;
808 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
809 if (!kmalloc_caches[i]) {
810 kmalloc_caches[i] = create_kmalloc_cache(NULL,
815 * Caches that are not of the two-to-the-power-of size.
816 * These have to be created immediately after the
817 * earlier power of two caches
819 if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6)
820 kmalloc_caches[1] = create_kmalloc_cache(NULL, 96, flags);
822 if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7)
823 kmalloc_caches[2] = create_kmalloc_cache(NULL, 192, flags);
826 /* Kmalloc array is now usable */
829 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
830 struct kmem_cache *s = kmalloc_caches[i];
834 n = kasprintf(GFP_NOWAIT, "kmalloc-%d", kmalloc_size(i));
841 #ifdef CONFIG_ZONE_DMA
842 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
843 struct kmem_cache *s = kmalloc_caches[i];
846 int size = kmalloc_size(i);
847 char *n = kasprintf(GFP_NOWAIT,
848 "dma-kmalloc-%d", size);
851 kmalloc_dma_caches[i] = create_kmalloc_cache(n,
852 size, SLAB_CACHE_DMA | flags);
857 #endif /* !CONFIG_SLOB */
860 * To avoid unnecessary overhead, we pass through large allocation requests
861 * directly to the page allocator. We use __GFP_COMP, because we will need to
862 * know the allocation order to free the pages properly in kfree.
864 void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
870 page = alloc_kmem_pages(flags, order);
871 ret = page ? page_address(page) : NULL;
872 kmemleak_alloc(ret, size, 1, flags);
875 EXPORT_SYMBOL(kmalloc_order);
877 #ifdef CONFIG_TRACING
878 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
880 void *ret = kmalloc_order(size, flags, order);
881 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
884 EXPORT_SYMBOL(kmalloc_order_trace);
887 #ifdef CONFIG_SLABINFO
890 #define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR)
892 #define SLABINFO_RIGHTS S_IRUSR
895 static void print_slabinfo_header(struct seq_file *m)
898 * Output format version, so at least we can change it
899 * without _too_ many complaints.
901 #ifdef CONFIG_DEBUG_SLAB
902 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
904 seq_puts(m, "slabinfo - version: 2.1\n");
906 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
907 "<objperslab> <pagesperslab>");
908 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
909 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
910 #ifdef CONFIG_DEBUG_SLAB
911 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
912 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
913 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
918 void *slab_start(struct seq_file *m, loff_t *pos)
920 mutex_lock(&slab_mutex);
921 return seq_list_start(&slab_caches, *pos);
924 void *slab_next(struct seq_file *m, void *p, loff_t *pos)
926 return seq_list_next(p, &slab_caches, pos);
929 void slab_stop(struct seq_file *m, void *p)
931 mutex_unlock(&slab_mutex);
935 memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
937 struct kmem_cache *c;
938 struct slabinfo sinfo;
940 if (!is_root_cache(s))
943 for_each_memcg_cache(c, s) {
944 memset(&sinfo, 0, sizeof(sinfo));
945 get_slabinfo(c, &sinfo);
947 info->active_slabs += sinfo.active_slabs;
948 info->num_slabs += sinfo.num_slabs;
949 info->shared_avail += sinfo.shared_avail;
950 info->active_objs += sinfo.active_objs;
951 info->num_objs += sinfo.num_objs;
955 static void cache_show(struct kmem_cache *s, struct seq_file *m)
957 struct slabinfo sinfo;
959 memset(&sinfo, 0, sizeof(sinfo));
960 get_slabinfo(s, &sinfo);
962 memcg_accumulate_slabinfo(s, &sinfo);
964 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
965 cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size,
966 sinfo.objects_per_slab, (1 << sinfo.cache_order));
968 seq_printf(m, " : tunables %4u %4u %4u",
969 sinfo.limit, sinfo.batchcount, sinfo.shared);
970 seq_printf(m, " : slabdata %6lu %6lu %6lu",
971 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
972 slabinfo_show_stats(m, s);
976 static int slab_show(struct seq_file *m, void *p)
978 struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
980 if (p == slab_caches.next)
981 print_slabinfo_header(m);
982 if (is_root_cache(s))
987 #ifdef CONFIG_MEMCG_KMEM
988 int memcg_slab_show(struct seq_file *m, void *p)
990 struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
991 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m));
993 if (p == slab_caches.next)
994 print_slabinfo_header(m);
995 if (!is_root_cache(s) && s->memcg_params.memcg == memcg)
1002 * slabinfo_op - iterator that generates /proc/slabinfo
1011 * num-pages-per-slab
1012 * + further values on SMP and with statistics enabled
1014 static const struct seq_operations slabinfo_op = {
1015 .start = slab_start,
1021 static int slabinfo_open(struct inode *inode, struct file *file)
1023 return seq_open(file, &slabinfo_op);
1026 static const struct file_operations proc_slabinfo_operations = {
1027 .open = slabinfo_open,
1029 .write = slabinfo_write,
1030 .llseek = seq_lseek,
1031 .release = seq_release,
1034 static int __init slab_proc_init(void)
1036 proc_create("slabinfo", SLABINFO_RIGHTS, NULL,
1037 &proc_slabinfo_operations);
1040 module_init(slab_proc_init);
1041 #endif /* CONFIG_SLABINFO */
1043 static __always_inline void *__do_krealloc(const void *p, size_t new_size,
1055 ret = kmalloc_track_caller(new_size, flags);
1063 * __krealloc - like krealloc() but don't free @p.
1064 * @p: object to reallocate memory for.
1065 * @new_size: how many bytes of memory are required.
1066 * @flags: the type of memory to allocate.
1068 * This function is like krealloc() except it never frees the originally
1069 * allocated buffer. Use this if you don't want to free the buffer immediately
1070 * like, for example, with RCU.
1072 void *__krealloc(const void *p, size_t new_size, gfp_t flags)
1074 if (unlikely(!new_size))
1075 return ZERO_SIZE_PTR;
1077 return __do_krealloc(p, new_size, flags);
1080 EXPORT_SYMBOL(__krealloc);
1083 * krealloc - reallocate memory. The contents will remain unchanged.
1084 * @p: object to reallocate memory for.
1085 * @new_size: how many bytes of memory are required.
1086 * @flags: the type of memory to allocate.
1088 * The contents of the object pointed to are preserved up to the
1089 * lesser of the new and old sizes. If @p is %NULL, krealloc()
1090 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
1091 * %NULL pointer, the object pointed to is freed.
1093 void *krealloc(const void *p, size_t new_size, gfp_t flags)
1097 if (unlikely(!new_size)) {
1099 return ZERO_SIZE_PTR;
1102 ret = __do_krealloc(p, new_size, flags);
1103 if (ret && p != ret)
1108 EXPORT_SYMBOL(krealloc);
1111 * kzfree - like kfree but zero memory
1112 * @p: object to free memory of
1114 * The memory of the object @p points to is zeroed before freed.
1115 * If @p is %NULL, kzfree() does nothing.
1117 * Note: this function zeroes the whole allocated buffer which can be a good
1118 * deal bigger than the requested buffer size passed to kmalloc(). So be
1119 * careful when using this function in performance sensitive code.
1121 void kzfree(const void *p)
1124 void *mem = (void *)p;
1126 if (unlikely(ZERO_OR_NULL_PTR(mem)))
1132 EXPORT_SYMBOL(kzfree);
1134 /* Tracepoints definitions. */
1135 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1136 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1137 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
1138 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
1139 EXPORT_TRACEPOINT_SYMBOL(kfree);
1140 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);