3 * Written by Mark Hemment, 1996/97.
4 * (markhe@nextd.demon.co.uk)
6 * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
8 * Major cleanup, different bufctl logic, per-cpu arrays
9 * (c) 2000 Manfred Spraul
11 * Cleanup, make the head arrays unconditional, preparation for NUMA
12 * (c) 2002 Manfred Spraul
14 * An implementation of the Slab Allocator as described in outline in;
15 * UNIX Internals: The New Frontiers by Uresh Vahalia
16 * Pub: Prentice Hall ISBN 0-13-101908-2
17 * or with a little more detail in;
18 * The Slab Allocator: An Object-Caching Kernel Memory Allocator
19 * Jeff Bonwick (Sun Microsystems).
20 * Presented at: USENIX Summer 1994 Technical Conference
22 * The memory is organized in caches, one cache for each object type.
23 * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
24 * Each cache consists out of many slabs (they are small (usually one
25 * page long) and always contiguous), and each slab contains multiple
26 * initialized objects.
28 * This means, that your constructor is used only for newly allocated
29 * slabs and you must pass objects with the same initializations to
32 * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM,
33 * normal). If you need a special memory type, then must create a new
34 * cache for that memory type.
36 * In order to reduce fragmentation, the slabs are sorted in 3 groups:
37 * full slabs with 0 free objects
39 * empty slabs with no allocated objects
41 * If partial slabs exist, then new allocations come from these slabs,
42 * otherwise from empty slabs or new slabs are allocated.
44 * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache
45 * during kmem_cache_destroy(). The caller must prevent concurrent allocs.
47 * Each cache has a short per-cpu head array, most allocs
48 * and frees go into that array, and if that array overflows, then 1/2
49 * of the entries in the array are given back into the global cache.
50 * The head array is strictly LIFO and should improve the cache hit rates.
51 * On SMP, it additionally reduces the spinlock operations.
53 * The c_cpuarray may not be read with enabled local interrupts -
54 * it's changed with a smp_call_function().
56 * SMP synchronization:
57 * constructors and destructors are called without any locking.
58 * Several members in struct kmem_cache and struct slab never change, they
59 * are accessed without any locking.
60 * The per-cpu arrays are never accessed from the wrong cpu, no locking,
61 * and local interrupts are disabled so slab code is preempt-safe.
62 * The non-constant members are protected with a per-cache irq spinlock.
64 * Many thanks to Mark Hemment, who wrote another per-cpu slab patch
65 * in 2000 - many ideas in the current implementation are derived from
68 * Further notes from the original documentation:
70 * 11 April '97. Started multi-threading - markhe
71 * The global cache-chain is protected by the mutex 'slab_mutex'.
72 * The sem is only needed when accessing/extending the cache-chain, which
73 * can never happen inside an interrupt (kmem_cache_create(),
74 * kmem_cache_shrink() and kmem_cache_reap()).
76 * At present, each engine can be growing a cache. This should be blocked.
78 * 15 March 2005. NUMA slab allocator.
79 * Shai Fultheim <shai@scalex86.org>.
80 * Shobhit Dayal <shobhit@calsoftinc.com>
81 * Alok N Kataria <alokk@calsoftinc.com>
82 * Christoph Lameter <christoph@lameter.com>
84 * Modified the slab allocator to be node aware on NUMA systems.
85 * Each node has its own list of partial, free and full slabs.
86 * All object allocations for a node occur from node specific slab lists.
89 #include <linux/slab.h>
91 #include <linux/poison.h>
92 #include <linux/swap.h>
93 #include <linux/cache.h>
94 #include <linux/interrupt.h>
95 #include <linux/init.h>
96 #include <linux/compiler.h>
97 #include <linux/cpuset.h>
98 #include <linux/proc_fs.h>
99 #include <linux/seq_file.h>
100 #include <linux/notifier.h>
101 #include <linux/kallsyms.h>
102 #include <linux/cpu.h>
103 #include <linux/sysctl.h>
104 #include <linux/module.h>
105 #include <linux/rcupdate.h>
106 #include <linux/string.h>
107 #include <linux/uaccess.h>
108 #include <linux/nodemask.h>
109 #include <linux/kmemleak.h>
110 #include <linux/mempolicy.h>
111 #include <linux/mutex.h>
112 #include <linux/fault-inject.h>
113 #include <linux/rtmutex.h>
114 #include <linux/reciprocal_div.h>
115 #include <linux/debugobjects.h>
116 #include <linux/kmemcheck.h>
117 #include <linux/memory.h>
118 #include <linux/prefetch.h>
120 #include <net/sock.h>
122 #include <asm/cacheflush.h>
123 #include <asm/tlbflush.h>
124 #include <asm/page.h>
126 #include <trace/events/kmem.h>
128 #include "internal.h"
133 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
134 * 0 for faster, smaller code (especially in the critical paths).
136 * STATS - 1 to collect stats for /proc/slabinfo.
137 * 0 for faster, smaller code (especially in the critical paths).
139 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
142 #ifdef CONFIG_DEBUG_SLAB
145 #define FORCED_DEBUG 1
149 #define FORCED_DEBUG 0
152 /* Shouldn't this be in a header file somewhere? */
153 #define BYTES_PER_WORD sizeof(void *)
154 #define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long))
156 #ifndef ARCH_KMALLOC_FLAGS
157 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
160 #define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \
161 <= SLAB_OBJ_MIN_SIZE) ? 1 : 0)
163 #if FREELIST_BYTE_INDEX
164 typedef unsigned char freelist_idx_t;
166 typedef unsigned short freelist_idx_t;
169 #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1)
175 * - LIFO ordering, to hand out cache-warm objects from _alloc
176 * - reduce the number of linked list operations
177 * - reduce spinlock operations
179 * The limit is stored in the per-cpu structure to reduce the data cache
186 unsigned int batchcount;
187 unsigned int touched;
189 * Must have this definition in here for the proper
190 * alignment of array_cache. Also simplifies accessing
197 struct array_cache ac;
201 * Need this for bootstrapping a per node allocator.
203 #define NUM_INIT_LISTS (2 * MAX_NUMNODES)
204 static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS];
205 #define CACHE_CACHE 0
206 #define SIZE_NODE (MAX_NUMNODES)
208 static int drain_freelist(struct kmem_cache *cache,
209 struct kmem_cache_node *n, int tofree);
210 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
211 int node, struct list_head *list);
212 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list);
213 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
214 static void cache_reap(struct work_struct *unused);
216 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
218 static inline void fixup_slab_list(struct kmem_cache *cachep,
219 struct kmem_cache_node *n, struct page *page,
221 static int slab_early_init = 1;
223 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
225 static void kmem_cache_node_init(struct kmem_cache_node *parent)
227 INIT_LIST_HEAD(&parent->slabs_full);
228 INIT_LIST_HEAD(&parent->slabs_partial);
229 INIT_LIST_HEAD(&parent->slabs_free);
230 parent->shared = NULL;
231 parent->alien = NULL;
232 parent->colour_next = 0;
233 spin_lock_init(&parent->list_lock);
234 parent->free_objects = 0;
235 parent->free_touched = 0;
238 #define MAKE_LIST(cachep, listp, slab, nodeid) \
240 INIT_LIST_HEAD(listp); \
241 list_splice(&get_node(cachep, nodeid)->slab, listp); \
244 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
246 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
247 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
248 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
251 #define CFLGS_OBJFREELIST_SLAB (0x40000000UL)
252 #define CFLGS_OFF_SLAB (0x80000000UL)
253 #define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB)
254 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
256 #define BATCHREFILL_LIMIT 16
258 * Optimization question: fewer reaps means less probability for unnessary
259 * cpucache drain/refill cycles.
261 * OTOH the cpuarrays can contain lots of objects,
262 * which could lock up otherwise freeable slabs.
264 #define REAPTIMEOUT_AC (2*HZ)
265 #define REAPTIMEOUT_NODE (4*HZ)
268 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
269 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
270 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
271 #define STATS_INC_GROWN(x) ((x)->grown++)
272 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
273 #define STATS_SET_HIGH(x) \
275 if ((x)->num_active > (x)->high_mark) \
276 (x)->high_mark = (x)->num_active; \
278 #define STATS_INC_ERR(x) ((x)->errors++)
279 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
280 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
281 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
282 #define STATS_SET_FREEABLE(x, i) \
284 if ((x)->max_freeable < i) \
285 (x)->max_freeable = i; \
287 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
288 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
289 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
290 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
292 #define STATS_INC_ACTIVE(x) do { } while (0)
293 #define STATS_DEC_ACTIVE(x) do { } while (0)
294 #define STATS_INC_ALLOCED(x) do { } while (0)
295 #define STATS_INC_GROWN(x) do { } while (0)
296 #define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0)
297 #define STATS_SET_HIGH(x) do { } while (0)
298 #define STATS_INC_ERR(x) do { } while (0)
299 #define STATS_INC_NODEALLOCS(x) do { } while (0)
300 #define STATS_INC_NODEFREES(x) do { } while (0)
301 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
302 #define STATS_SET_FREEABLE(x, i) do { } while (0)
303 #define STATS_INC_ALLOCHIT(x) do { } while (0)
304 #define STATS_INC_ALLOCMISS(x) do { } while (0)
305 #define STATS_INC_FREEHIT(x) do { } while (0)
306 #define STATS_INC_FREEMISS(x) do { } while (0)
312 * memory layout of objects:
314 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
315 * the end of an object is aligned with the end of the real
316 * allocation. Catches writes behind the end of the allocation.
317 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
319 * cachep->obj_offset: The real object.
320 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
321 * cachep->size - 1* BYTES_PER_WORD: last caller address
322 * [BYTES_PER_WORD long]
324 static int obj_offset(struct kmem_cache *cachep)
326 return cachep->obj_offset;
329 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
331 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
332 return (unsigned long long*) (objp + obj_offset(cachep) -
333 sizeof(unsigned long long));
336 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
338 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
339 if (cachep->flags & SLAB_STORE_USER)
340 return (unsigned long long *)(objp + cachep->size -
341 sizeof(unsigned long long) -
343 return (unsigned long long *) (objp + cachep->size -
344 sizeof(unsigned long long));
347 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
349 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
350 return (void **)(objp + cachep->size - BYTES_PER_WORD);
355 #define obj_offset(x) 0
356 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
357 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
358 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
362 #ifdef CONFIG_DEBUG_SLAB_LEAK
364 static inline bool is_store_user_clean(struct kmem_cache *cachep)
366 return atomic_read(&cachep->store_user_clean) == 1;
369 static inline void set_store_user_clean(struct kmem_cache *cachep)
371 atomic_set(&cachep->store_user_clean, 1);
374 static inline void set_store_user_dirty(struct kmem_cache *cachep)
376 if (is_store_user_clean(cachep))
377 atomic_set(&cachep->store_user_clean, 0);
381 static inline void set_store_user_dirty(struct kmem_cache *cachep) {}
386 * Do not go above this order unless 0 objects fit into the slab or
387 * overridden on the command line.
389 #define SLAB_MAX_ORDER_HI 1
390 #define SLAB_MAX_ORDER_LO 0
391 static int slab_max_order = SLAB_MAX_ORDER_LO;
392 static bool slab_max_order_set __initdata;
394 static inline struct kmem_cache *virt_to_cache(const void *obj)
396 struct page *page = virt_to_head_page(obj);
397 return page->slab_cache;
400 static inline void *index_to_obj(struct kmem_cache *cache, struct page *page,
403 return page->s_mem + cache->size * idx;
407 * We want to avoid an expensive divide : (offset / cache->size)
408 * Using the fact that size is a constant for a particular cache,
409 * we can replace (offset / cache->size) by
410 * reciprocal_divide(offset, cache->reciprocal_buffer_size)
412 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
413 const struct page *page, void *obj)
415 u32 offset = (obj - page->s_mem);
416 return reciprocal_divide(offset, cache->reciprocal_buffer_size);
419 #define BOOT_CPUCACHE_ENTRIES 1
420 /* internal cache of cache description objs */
421 static struct kmem_cache kmem_cache_boot = {
423 .limit = BOOT_CPUCACHE_ENTRIES,
425 .size = sizeof(struct kmem_cache),
426 .name = "kmem_cache",
429 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
431 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
433 return this_cpu_ptr(cachep->cpu_cache);
437 * Calculate the number of objects and left-over bytes for a given buffer size.
439 static unsigned int cache_estimate(unsigned long gfporder, size_t buffer_size,
440 unsigned long flags, size_t *left_over)
443 size_t slab_size = PAGE_SIZE << gfporder;
446 * The slab management structure can be either off the slab or
447 * on it. For the latter case, the memory allocated for a
450 * - @buffer_size bytes for each object
451 * - One freelist_idx_t for each object
453 * We don't need to consider alignment of freelist because
454 * freelist will be at the end of slab page. The objects will be
455 * at the correct alignment.
457 * If the slab management structure is off the slab, then the
458 * alignment will already be calculated into the size. Because
459 * the slabs are all pages aligned, the objects will be at the
460 * correct alignment when allocated.
462 if (flags & (CFLGS_OBJFREELIST_SLAB | CFLGS_OFF_SLAB)) {
463 num = slab_size / buffer_size;
464 *left_over = slab_size % buffer_size;
466 num = slab_size / (buffer_size + sizeof(freelist_idx_t));
467 *left_over = slab_size %
468 (buffer_size + sizeof(freelist_idx_t));
475 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
477 static void __slab_error(const char *function, struct kmem_cache *cachep,
480 pr_err("slab error in %s(): cache `%s': %s\n",
481 function, cachep->name, msg);
483 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
488 * By default on NUMA we use alien caches to stage the freeing of
489 * objects allocated from other nodes. This causes massive memory
490 * inefficiencies when using fake NUMA setup to split memory into a
491 * large number of small nodes, so it can be disabled on the command
495 static int use_alien_caches __read_mostly = 1;
496 static int __init noaliencache_setup(char *s)
498 use_alien_caches = 0;
501 __setup("noaliencache", noaliencache_setup);
503 static int __init slab_max_order_setup(char *str)
505 get_option(&str, &slab_max_order);
506 slab_max_order = slab_max_order < 0 ? 0 :
507 min(slab_max_order, MAX_ORDER - 1);
508 slab_max_order_set = true;
512 __setup("slab_max_order=", slab_max_order_setup);
516 * Special reaping functions for NUMA systems called from cache_reap().
517 * These take care of doing round robin flushing of alien caches (containing
518 * objects freed on different nodes from which they were allocated) and the
519 * flushing of remote pcps by calling drain_node_pages.
521 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
523 static void init_reap_node(int cpu)
525 per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu),
529 static void next_reap_node(void)
531 int node = __this_cpu_read(slab_reap_node);
533 node = next_node_in(node, node_online_map);
534 __this_cpu_write(slab_reap_node, node);
538 #define init_reap_node(cpu) do { } while (0)
539 #define next_reap_node(void) do { } while (0)
543 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
544 * via the workqueue/eventd.
545 * Add the CPU number into the expiration time to minimize the possibility of
546 * the CPUs getting into lockstep and contending for the global cache chain
549 static void start_cpu_timer(int cpu)
551 struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
554 * When this gets called from do_initcalls via cpucache_init(),
555 * init_workqueues() has already run, so keventd will be setup
558 if (keventd_up() && reap_work->work.func == NULL) {
560 INIT_DEFERRABLE_WORK(reap_work, cache_reap);
561 schedule_delayed_work_on(cpu, reap_work,
562 __round_jiffies_relative(HZ, cpu));
566 static void init_arraycache(struct array_cache *ac, int limit, int batch)
569 * The array_cache structures contain pointers to free object.
570 * However, when such objects are allocated or transferred to another
571 * cache the pointers are not cleared and they could be counted as
572 * valid references during a kmemleak scan. Therefore, kmemleak must
573 * not scan such objects.
575 kmemleak_no_scan(ac);
579 ac->batchcount = batch;
584 static struct array_cache *alloc_arraycache(int node, int entries,
585 int batchcount, gfp_t gfp)
587 size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache);
588 struct array_cache *ac = NULL;
590 ac = kmalloc_node(memsize, gfp, node);
591 init_arraycache(ac, entries, batchcount);
595 static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep,
596 struct page *page, void *objp)
598 struct kmem_cache_node *n;
602 page_node = page_to_nid(page);
603 n = get_node(cachep, page_node);
605 spin_lock(&n->list_lock);
606 free_block(cachep, &objp, 1, page_node, &list);
607 spin_unlock(&n->list_lock);
609 slabs_destroy(cachep, &list);
613 * Transfer objects in one arraycache to another.
614 * Locking must be handled by the caller.
616 * Return the number of entries transferred.
618 static int transfer_objects(struct array_cache *to,
619 struct array_cache *from, unsigned int max)
621 /* Figure out how many entries to transfer */
622 int nr = min3(from->avail, max, to->limit - to->avail);
627 memcpy(to->entry + to->avail, from->entry + from->avail -nr,
637 #define drain_alien_cache(cachep, alien) do { } while (0)
638 #define reap_alien(cachep, n) do { } while (0)
640 static inline struct alien_cache **alloc_alien_cache(int node,
641 int limit, gfp_t gfp)
646 static inline void free_alien_cache(struct alien_cache **ac_ptr)
650 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
655 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
661 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
662 gfp_t flags, int nodeid)
667 static inline gfp_t gfp_exact_node(gfp_t flags)
669 return flags & ~__GFP_NOFAIL;
672 #else /* CONFIG_NUMA */
674 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
675 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
677 static struct alien_cache *__alloc_alien_cache(int node, int entries,
678 int batch, gfp_t gfp)
680 size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache);
681 struct alien_cache *alc = NULL;
683 alc = kmalloc_node(memsize, gfp, node);
684 init_arraycache(&alc->ac, entries, batch);
685 spin_lock_init(&alc->lock);
689 static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
691 struct alien_cache **alc_ptr;
692 size_t memsize = sizeof(void *) * nr_node_ids;
697 alc_ptr = kzalloc_node(memsize, gfp, node);
702 if (i == node || !node_online(i))
704 alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp);
706 for (i--; i >= 0; i--)
715 static void free_alien_cache(struct alien_cache **alc_ptr)
726 static void __drain_alien_cache(struct kmem_cache *cachep,
727 struct array_cache *ac, int node,
728 struct list_head *list)
730 struct kmem_cache_node *n = get_node(cachep, node);
733 spin_lock(&n->list_lock);
735 * Stuff objects into the remote nodes shared array first.
736 * That way we could avoid the overhead of putting the objects
737 * into the free lists and getting them back later.
740 transfer_objects(n->shared, ac, ac->limit);
742 free_block(cachep, ac->entry, ac->avail, node, list);
744 spin_unlock(&n->list_lock);
749 * Called from cache_reap() to regularly drain alien caches round robin.
751 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
753 int node = __this_cpu_read(slab_reap_node);
756 struct alien_cache *alc = n->alien[node];
757 struct array_cache *ac;
761 if (ac->avail && spin_trylock_irq(&alc->lock)) {
764 __drain_alien_cache(cachep, ac, node, &list);
765 spin_unlock_irq(&alc->lock);
766 slabs_destroy(cachep, &list);
772 static void drain_alien_cache(struct kmem_cache *cachep,
773 struct alien_cache **alien)
776 struct alien_cache *alc;
777 struct array_cache *ac;
780 for_each_online_node(i) {
786 spin_lock_irqsave(&alc->lock, flags);
787 __drain_alien_cache(cachep, ac, i, &list);
788 spin_unlock_irqrestore(&alc->lock, flags);
789 slabs_destroy(cachep, &list);
794 static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
795 int node, int page_node)
797 struct kmem_cache_node *n;
798 struct alien_cache *alien = NULL;
799 struct array_cache *ac;
802 n = get_node(cachep, node);
803 STATS_INC_NODEFREES(cachep);
804 if (n->alien && n->alien[page_node]) {
805 alien = n->alien[page_node];
807 spin_lock(&alien->lock);
808 if (unlikely(ac->avail == ac->limit)) {
809 STATS_INC_ACOVERFLOW(cachep);
810 __drain_alien_cache(cachep, ac, page_node, &list);
812 ac->entry[ac->avail++] = objp;
813 spin_unlock(&alien->lock);
814 slabs_destroy(cachep, &list);
816 n = get_node(cachep, page_node);
817 spin_lock(&n->list_lock);
818 free_block(cachep, &objp, 1, page_node, &list);
819 spin_unlock(&n->list_lock);
820 slabs_destroy(cachep, &list);
825 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
827 int page_node = page_to_nid(virt_to_page(objp));
828 int node = numa_mem_id();
830 * Make sure we are not freeing a object from another node to the array
833 if (likely(node == page_node))
836 return __cache_free_alien(cachep, objp, node, page_node);
840 * Construct gfp mask to allocate from a specific node but do not reclaim or
841 * warn about failures.
843 static inline gfp_t gfp_exact_node(gfp_t flags)
845 return (flags | __GFP_THISNODE | __GFP_NOWARN) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
849 static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp)
851 struct kmem_cache_node *n;
854 * Set up the kmem_cache_node for cpu before we can
855 * begin anything. Make sure some other cpu on this
856 * node has not already allocated this
858 n = get_node(cachep, node);
860 spin_lock_irq(&n->list_lock);
861 n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount +
863 spin_unlock_irq(&n->list_lock);
868 n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
872 kmem_cache_node_init(n);
873 n->next_reap = jiffies + REAPTIMEOUT_NODE +
874 ((unsigned long)cachep) % REAPTIMEOUT_NODE;
877 (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num;
880 * The kmem_cache_nodes don't come and go as CPUs
881 * come and go. slab_mutex is sufficient
884 cachep->node[node] = n;
890 * Allocates and initializes node for a node on each slab cache, used for
891 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node
892 * will be allocated off-node since memory is not yet online for the new node.
893 * When hotplugging memory or a cpu, existing node are not replaced if
896 * Must hold slab_mutex.
898 static int init_cache_node_node(int node)
901 struct kmem_cache *cachep;
903 list_for_each_entry(cachep, &slab_caches, list) {
904 ret = init_cache_node(cachep, node, GFP_KERNEL);
912 static int setup_kmem_cache_node(struct kmem_cache *cachep,
913 int node, gfp_t gfp, bool force_change)
916 struct kmem_cache_node *n;
917 struct array_cache *old_shared = NULL;
918 struct array_cache *new_shared = NULL;
919 struct alien_cache **new_alien = NULL;
922 if (use_alien_caches) {
923 new_alien = alloc_alien_cache(node, cachep->limit, gfp);
928 if (cachep->shared) {
929 new_shared = alloc_arraycache(node,
930 cachep->shared * cachep->batchcount, 0xbaadf00d, gfp);
935 ret = init_cache_node(cachep, node, gfp);
939 n = get_node(cachep, node);
940 spin_lock_irq(&n->list_lock);
941 if (n->shared && force_change) {
942 free_block(cachep, n->shared->entry,
943 n->shared->avail, node, &list);
944 n->shared->avail = 0;
947 if (!n->shared || force_change) {
948 old_shared = n->shared;
949 n->shared = new_shared;
954 n->alien = new_alien;
958 spin_unlock_irq(&n->list_lock);
959 slabs_destroy(cachep, &list);
962 * To protect lockless access to n->shared during irq disabled context.
963 * If n->shared isn't NULL in irq disabled context, accessing to it is
964 * guaranteed to be valid until irq is re-enabled, because it will be
965 * freed after synchronize_sched().
973 free_alien_cache(new_alien);
978 static void cpuup_canceled(long cpu)
980 struct kmem_cache *cachep;
981 struct kmem_cache_node *n = NULL;
982 int node = cpu_to_mem(cpu);
983 const struct cpumask *mask = cpumask_of_node(node);
985 list_for_each_entry(cachep, &slab_caches, list) {
986 struct array_cache *nc;
987 struct array_cache *shared;
988 struct alien_cache **alien;
991 n = get_node(cachep, node);
995 spin_lock_irq(&n->list_lock);
997 /* Free limit for this kmem_cache_node */
998 n->free_limit -= cachep->batchcount;
1000 /* cpu is dead; no one can alloc from it. */
1001 nc = per_cpu_ptr(cachep->cpu_cache, cpu);
1003 free_block(cachep, nc->entry, nc->avail, node, &list);
1007 if (!cpumask_empty(mask)) {
1008 spin_unlock_irq(&n->list_lock);
1014 free_block(cachep, shared->entry,
1015 shared->avail, node, &list);
1022 spin_unlock_irq(&n->list_lock);
1026 drain_alien_cache(cachep, alien);
1027 free_alien_cache(alien);
1031 slabs_destroy(cachep, &list);
1034 * In the previous loop, all the objects were freed to
1035 * the respective cache's slabs, now we can go ahead and
1036 * shrink each nodelist to its limit.
1038 list_for_each_entry(cachep, &slab_caches, list) {
1039 n = get_node(cachep, node);
1042 drain_freelist(cachep, n, INT_MAX);
1046 static int cpuup_prepare(long cpu)
1048 struct kmem_cache *cachep;
1049 int node = cpu_to_mem(cpu);
1053 * We need to do this right in the beginning since
1054 * alloc_arraycache's are going to use this list.
1055 * kmalloc_node allows us to add the slab to the right
1056 * kmem_cache_node and not this cpu's kmem_cache_node
1058 err = init_cache_node_node(node);
1063 * Now we can go ahead with allocating the shared arrays and
1066 list_for_each_entry(cachep, &slab_caches, list) {
1067 err = setup_kmem_cache_node(cachep, node, GFP_KERNEL, false);
1074 cpuup_canceled(cpu);
1078 static int cpuup_callback(struct notifier_block *nfb,
1079 unsigned long action, void *hcpu)
1081 long cpu = (long)hcpu;
1085 case CPU_UP_PREPARE:
1086 case CPU_UP_PREPARE_FROZEN:
1087 mutex_lock(&slab_mutex);
1088 err = cpuup_prepare(cpu);
1089 mutex_unlock(&slab_mutex);
1092 case CPU_ONLINE_FROZEN:
1093 start_cpu_timer(cpu);
1095 #ifdef CONFIG_HOTPLUG_CPU
1096 case CPU_DOWN_PREPARE:
1097 case CPU_DOWN_PREPARE_FROZEN:
1099 * Shutdown cache reaper. Note that the slab_mutex is
1100 * held so that if cache_reap() is invoked it cannot do
1101 * anything expensive but will only modify reap_work
1102 * and reschedule the timer.
1104 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
1105 /* Now the cache_reaper is guaranteed to be not running. */
1106 per_cpu(slab_reap_work, cpu).work.func = NULL;
1108 case CPU_DOWN_FAILED:
1109 case CPU_DOWN_FAILED_FROZEN:
1110 start_cpu_timer(cpu);
1113 case CPU_DEAD_FROZEN:
1115 * Even if all the cpus of a node are down, we don't free the
1116 * kmem_cache_node of any cache. This to avoid a race between
1117 * cpu_down, and a kmalloc allocation from another cpu for
1118 * memory from the node of the cpu going down. The node
1119 * structure is usually allocated from kmem_cache_create() and
1120 * gets destroyed at kmem_cache_destroy().
1124 case CPU_UP_CANCELED:
1125 case CPU_UP_CANCELED_FROZEN:
1126 mutex_lock(&slab_mutex);
1127 cpuup_canceled(cpu);
1128 mutex_unlock(&slab_mutex);
1131 return notifier_from_errno(err);
1134 static struct notifier_block cpucache_notifier = {
1135 &cpuup_callback, NULL, 0
1138 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1140 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1141 * Returns -EBUSY if all objects cannot be drained so that the node is not
1144 * Must hold slab_mutex.
1146 static int __meminit drain_cache_node_node(int node)
1148 struct kmem_cache *cachep;
1151 list_for_each_entry(cachep, &slab_caches, list) {
1152 struct kmem_cache_node *n;
1154 n = get_node(cachep, node);
1158 drain_freelist(cachep, n, INT_MAX);
1160 if (!list_empty(&n->slabs_full) ||
1161 !list_empty(&n->slabs_partial)) {
1169 static int __meminit slab_memory_callback(struct notifier_block *self,
1170 unsigned long action, void *arg)
1172 struct memory_notify *mnb = arg;
1176 nid = mnb->status_change_nid;
1181 case MEM_GOING_ONLINE:
1182 mutex_lock(&slab_mutex);
1183 ret = init_cache_node_node(nid);
1184 mutex_unlock(&slab_mutex);
1186 case MEM_GOING_OFFLINE:
1187 mutex_lock(&slab_mutex);
1188 ret = drain_cache_node_node(nid);
1189 mutex_unlock(&slab_mutex);
1193 case MEM_CANCEL_ONLINE:
1194 case MEM_CANCEL_OFFLINE:
1198 return notifier_from_errno(ret);
1200 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1203 * swap the static kmem_cache_node with kmalloced memory
1205 static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list,
1208 struct kmem_cache_node *ptr;
1210 ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid);
1213 memcpy(ptr, list, sizeof(struct kmem_cache_node));
1215 * Do not assume that spinlocks can be initialized via memcpy:
1217 spin_lock_init(&ptr->list_lock);
1219 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1220 cachep->node[nodeid] = ptr;
1224 * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1225 * size of kmem_cache_node.
1227 static void __init set_up_node(struct kmem_cache *cachep, int index)
1231 for_each_online_node(node) {
1232 cachep->node[node] = &init_kmem_cache_node[index + node];
1233 cachep->node[node]->next_reap = jiffies +
1235 ((unsigned long)cachep) % REAPTIMEOUT_NODE;
1240 * Initialisation. Called after the page allocator have been initialised and
1241 * before smp_init().
1243 void __init kmem_cache_init(void)
1247 BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) <
1248 sizeof(struct rcu_head));
1249 kmem_cache = &kmem_cache_boot;
1251 if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1)
1252 use_alien_caches = 0;
1254 for (i = 0; i < NUM_INIT_LISTS; i++)
1255 kmem_cache_node_init(&init_kmem_cache_node[i]);
1258 * Fragmentation resistance on low memory - only use bigger
1259 * page orders on machines with more than 32MB of memory if
1260 * not overridden on the command line.
1262 if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
1263 slab_max_order = SLAB_MAX_ORDER_HI;
1265 /* Bootstrap is tricky, because several objects are allocated
1266 * from caches that do not exist yet:
1267 * 1) initialize the kmem_cache cache: it contains the struct
1268 * kmem_cache structures of all caches, except kmem_cache itself:
1269 * kmem_cache is statically allocated.
1270 * Initially an __init data area is used for the head array and the
1271 * kmem_cache_node structures, it's replaced with a kmalloc allocated
1272 * array at the end of the bootstrap.
1273 * 2) Create the first kmalloc cache.
1274 * The struct kmem_cache for the new cache is allocated normally.
1275 * An __init data area is used for the head array.
1276 * 3) Create the remaining kmalloc caches, with minimally sized
1278 * 4) Replace the __init data head arrays for kmem_cache and the first
1279 * kmalloc cache with kmalloc allocated arrays.
1280 * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1281 * the other cache's with kmalloc allocated memory.
1282 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1285 /* 1) create the kmem_cache */
1288 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1290 create_boot_cache(kmem_cache, "kmem_cache",
1291 offsetof(struct kmem_cache, node) +
1292 nr_node_ids * sizeof(struct kmem_cache_node *),
1293 SLAB_HWCACHE_ALIGN);
1294 list_add(&kmem_cache->list, &slab_caches);
1295 slab_state = PARTIAL;
1298 * Initialize the caches that provide memory for the kmem_cache_node
1299 * structures first. Without this, further allocations will bug.
1301 kmalloc_caches[INDEX_NODE] = create_kmalloc_cache("kmalloc-node",
1302 kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS);
1303 slab_state = PARTIAL_NODE;
1304 setup_kmalloc_cache_index_table();
1306 slab_early_init = 0;
1308 /* 5) Replace the bootstrap kmem_cache_node */
1312 for_each_online_node(nid) {
1313 init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid);
1315 init_list(kmalloc_caches[INDEX_NODE],
1316 &init_kmem_cache_node[SIZE_NODE + nid], nid);
1320 create_kmalloc_caches(ARCH_KMALLOC_FLAGS);
1323 void __init kmem_cache_init_late(void)
1325 struct kmem_cache *cachep;
1329 /* 6) resize the head arrays to their final sizes */
1330 mutex_lock(&slab_mutex);
1331 list_for_each_entry(cachep, &slab_caches, list)
1332 if (enable_cpucache(cachep, GFP_NOWAIT))
1334 mutex_unlock(&slab_mutex);
1340 * Register a cpu startup notifier callback that initializes
1341 * cpu_cache_get for all new cpus
1343 register_cpu_notifier(&cpucache_notifier);
1347 * Register a memory hotplug callback that initializes and frees
1350 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
1354 * The reap timers are started later, with a module init call: That part
1355 * of the kernel is not yet operational.
1359 static int __init cpucache_init(void)
1364 * Register the timers that return unneeded pages to the page allocator
1366 for_each_online_cpu(cpu)
1367 start_cpu_timer(cpu);
1373 __initcall(cpucache_init);
1375 static noinline void
1376 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
1379 struct kmem_cache_node *n;
1381 unsigned long flags;
1383 static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
1384 DEFAULT_RATELIMIT_BURST);
1386 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs))
1389 pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
1390 nodeid, gfpflags, &gfpflags);
1391 pr_warn(" cache: %s, object size: %d, order: %d\n",
1392 cachep->name, cachep->size, cachep->gfporder);
1394 for_each_kmem_cache_node(cachep, node, n) {
1395 unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
1396 unsigned long active_slabs = 0, num_slabs = 0;
1398 spin_lock_irqsave(&n->list_lock, flags);
1399 list_for_each_entry(page, &n->slabs_full, lru) {
1400 active_objs += cachep->num;
1403 list_for_each_entry(page, &n->slabs_partial, lru) {
1404 active_objs += page->active;
1407 list_for_each_entry(page, &n->slabs_free, lru)
1410 free_objects += n->free_objects;
1411 spin_unlock_irqrestore(&n->list_lock, flags);
1413 num_slabs += active_slabs;
1414 num_objs = num_slabs * cachep->num;
1415 pr_warn(" node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
1416 node, active_slabs, num_slabs, active_objs, num_objs,
1423 * Interface to system's page allocator. No need to hold the
1424 * kmem_cache_node ->list_lock.
1426 * If we requested dmaable memory, we will get it. Even if we
1427 * did not request dmaable memory, we might get it, but that
1428 * would be relatively rare and ignorable.
1430 static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
1436 flags |= cachep->allocflags;
1437 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1438 flags |= __GFP_RECLAIMABLE;
1440 page = __alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1442 slab_out_of_memory(cachep, flags, nodeid);
1446 if (memcg_charge_slab(page, flags, cachep->gfporder, cachep)) {
1447 __free_pages(page, cachep->gfporder);
1451 nr_pages = (1 << cachep->gfporder);
1452 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1453 add_zone_page_state(page_zone(page),
1454 NR_SLAB_RECLAIMABLE, nr_pages);
1456 add_zone_page_state(page_zone(page),
1457 NR_SLAB_UNRECLAIMABLE, nr_pages);
1459 __SetPageSlab(page);
1460 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1461 if (sk_memalloc_socks() && page_is_pfmemalloc(page))
1462 SetPageSlabPfmemalloc(page);
1464 if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1465 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1468 kmemcheck_mark_uninitialized_pages(page, nr_pages);
1470 kmemcheck_mark_unallocated_pages(page, nr_pages);
1477 * Interface to system's page release.
1479 static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
1481 int order = cachep->gfporder;
1482 unsigned long nr_freed = (1 << order);
1484 kmemcheck_free_shadow(page, order);
1486 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1487 sub_zone_page_state(page_zone(page),
1488 NR_SLAB_RECLAIMABLE, nr_freed);
1490 sub_zone_page_state(page_zone(page),
1491 NR_SLAB_UNRECLAIMABLE, nr_freed);
1493 BUG_ON(!PageSlab(page));
1494 __ClearPageSlabPfmemalloc(page);
1495 __ClearPageSlab(page);
1496 page_mapcount_reset(page);
1497 page->mapping = NULL;
1499 if (current->reclaim_state)
1500 current->reclaim_state->reclaimed_slab += nr_freed;
1501 memcg_uncharge_slab(page, order, cachep);
1502 __free_pages(page, order);
1505 static void kmem_rcu_free(struct rcu_head *head)
1507 struct kmem_cache *cachep;
1510 page = container_of(head, struct page, rcu_head);
1511 cachep = page->slab_cache;
1513 kmem_freepages(cachep, page);
1517 static bool is_debug_pagealloc_cache(struct kmem_cache *cachep)
1519 if (debug_pagealloc_enabled() && OFF_SLAB(cachep) &&
1520 (cachep->size % PAGE_SIZE) == 0)
1526 #ifdef CONFIG_DEBUG_PAGEALLOC
1527 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1528 unsigned long caller)
1530 int size = cachep->object_size;
1532 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1534 if (size < 5 * sizeof(unsigned long))
1537 *addr++ = 0x12345678;
1539 *addr++ = smp_processor_id();
1540 size -= 3 * sizeof(unsigned long);
1542 unsigned long *sptr = &caller;
1543 unsigned long svalue;
1545 while (!kstack_end(sptr)) {
1547 if (kernel_text_address(svalue)) {
1549 size -= sizeof(unsigned long);
1550 if (size <= sizeof(unsigned long))
1556 *addr++ = 0x87654321;
1559 static void slab_kernel_map(struct kmem_cache *cachep, void *objp,
1560 int map, unsigned long caller)
1562 if (!is_debug_pagealloc_cache(cachep))
1566 store_stackinfo(cachep, objp, caller);
1568 kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map);
1572 static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp,
1573 int map, unsigned long caller) {}
1577 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1579 int size = cachep->object_size;
1580 addr = &((char *)addr)[obj_offset(cachep)];
1582 memset(addr, val, size);
1583 *(unsigned char *)(addr + size - 1) = POISON_END;
1586 static void dump_line(char *data, int offset, int limit)
1589 unsigned char error = 0;
1592 pr_err("%03x: ", offset);
1593 for (i = 0; i < limit; i++) {
1594 if (data[offset + i] != POISON_FREE) {
1595 error = data[offset + i];
1599 print_hex_dump(KERN_CONT, "", 0, 16, 1,
1600 &data[offset], limit, 1);
1602 if (bad_count == 1) {
1603 error ^= POISON_FREE;
1604 if (!(error & (error - 1))) {
1605 pr_err("Single bit error detected. Probably bad RAM.\n");
1607 pr_err("Run memtest86+ or a similar memory test tool.\n");
1609 pr_err("Run a memory test tool.\n");
1618 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1623 if (cachep->flags & SLAB_RED_ZONE) {
1624 pr_err("Redzone: 0x%llx/0x%llx\n",
1625 *dbg_redzone1(cachep, objp),
1626 *dbg_redzone2(cachep, objp));
1629 if (cachep->flags & SLAB_STORE_USER) {
1630 pr_err("Last user: [<%p>](%pSR)\n",
1631 *dbg_userword(cachep, objp),
1632 *dbg_userword(cachep, objp));
1634 realobj = (char *)objp + obj_offset(cachep);
1635 size = cachep->object_size;
1636 for (i = 0; i < size && lines; i += 16, lines--) {
1639 if (i + limit > size)
1641 dump_line(realobj, i, limit);
1645 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1651 if (is_debug_pagealloc_cache(cachep))
1654 realobj = (char *)objp + obj_offset(cachep);
1655 size = cachep->object_size;
1657 for (i = 0; i < size; i++) {
1658 char exp = POISON_FREE;
1661 if (realobj[i] != exp) {
1666 pr_err("Slab corruption (%s): %s start=%p, len=%d\n",
1667 print_tainted(), cachep->name,
1669 print_objinfo(cachep, objp, 0);
1671 /* Hexdump the affected line */
1674 if (i + limit > size)
1676 dump_line(realobj, i, limit);
1679 /* Limit to 5 lines */
1685 /* Print some data about the neighboring objects, if they
1688 struct page *page = virt_to_head_page(objp);
1691 objnr = obj_to_index(cachep, page, objp);
1693 objp = index_to_obj(cachep, page, objnr - 1);
1694 realobj = (char *)objp + obj_offset(cachep);
1695 pr_err("Prev obj: start=%p, len=%d\n", realobj, size);
1696 print_objinfo(cachep, objp, 2);
1698 if (objnr + 1 < cachep->num) {
1699 objp = index_to_obj(cachep, page, objnr + 1);
1700 realobj = (char *)objp + obj_offset(cachep);
1701 pr_err("Next obj: start=%p, len=%d\n", realobj, size);
1702 print_objinfo(cachep, objp, 2);
1709 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1714 if (OBJFREELIST_SLAB(cachep) && cachep->flags & SLAB_POISON) {
1715 poison_obj(cachep, page->freelist - obj_offset(cachep),
1719 for (i = 0; i < cachep->num; i++) {
1720 void *objp = index_to_obj(cachep, page, i);
1722 if (cachep->flags & SLAB_POISON) {
1723 check_poison_obj(cachep, objp);
1724 slab_kernel_map(cachep, objp, 1, 0);
1726 if (cachep->flags & SLAB_RED_ZONE) {
1727 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1728 slab_error(cachep, "start of a freed object was overwritten");
1729 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1730 slab_error(cachep, "end of a freed object was overwritten");
1735 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1742 * slab_destroy - destroy and release all objects in a slab
1743 * @cachep: cache pointer being destroyed
1744 * @page: page pointer being destroyed
1746 * Destroy all the objs in a slab page, and release the mem back to the system.
1747 * Before calling the slab page must have been unlinked from the cache. The
1748 * kmem_cache_node ->list_lock is not held/needed.
1750 static void slab_destroy(struct kmem_cache *cachep, struct page *page)
1754 freelist = page->freelist;
1755 slab_destroy_debugcheck(cachep, page);
1756 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
1757 call_rcu(&page->rcu_head, kmem_rcu_free);
1759 kmem_freepages(cachep, page);
1762 * From now on, we don't use freelist
1763 * although actual page can be freed in rcu context
1765 if (OFF_SLAB(cachep))
1766 kmem_cache_free(cachep->freelist_cache, freelist);
1769 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list)
1771 struct page *page, *n;
1773 list_for_each_entry_safe(page, n, list, lru) {
1774 list_del(&page->lru);
1775 slab_destroy(cachep, page);
1780 * calculate_slab_order - calculate size (page order) of slabs
1781 * @cachep: pointer to the cache that is being created
1782 * @size: size of objects to be created in this cache.
1783 * @flags: slab allocation flags
1785 * Also calculates the number of objects per slab.
1787 * This could be made much more intelligent. For now, try to avoid using
1788 * high order pages for slabs. When the gfp() functions are more friendly
1789 * towards high-order requests, this should be changed.
1791 static size_t calculate_slab_order(struct kmem_cache *cachep,
1792 size_t size, unsigned long flags)
1794 size_t left_over = 0;
1797 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
1801 num = cache_estimate(gfporder, size, flags, &remainder);
1805 /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */
1806 if (num > SLAB_OBJ_MAX_NUM)
1809 if (flags & CFLGS_OFF_SLAB) {
1810 struct kmem_cache *freelist_cache;
1811 size_t freelist_size;
1813 freelist_size = num * sizeof(freelist_idx_t);
1814 freelist_cache = kmalloc_slab(freelist_size, 0u);
1815 if (!freelist_cache)
1819 * Needed to avoid possible looping condition
1820 * in cache_grow_begin()
1822 if (OFF_SLAB(freelist_cache))
1825 /* check if off slab has enough benefit */
1826 if (freelist_cache->size > cachep->size / 2)
1830 /* Found something acceptable - save it away */
1832 cachep->gfporder = gfporder;
1833 left_over = remainder;
1836 * A VFS-reclaimable slab tends to have most allocations
1837 * as GFP_NOFS and we really don't want to have to be allocating
1838 * higher-order pages when we are unable to shrink dcache.
1840 if (flags & SLAB_RECLAIM_ACCOUNT)
1844 * Large number of objects is good, but very large slabs are
1845 * currently bad for the gfp()s.
1847 if (gfporder >= slab_max_order)
1851 * Acceptable internal fragmentation?
1853 if (left_over * 8 <= (PAGE_SIZE << gfporder))
1859 static struct array_cache __percpu *alloc_kmem_cache_cpus(
1860 struct kmem_cache *cachep, int entries, int batchcount)
1864 struct array_cache __percpu *cpu_cache;
1866 size = sizeof(void *) * entries + sizeof(struct array_cache);
1867 cpu_cache = __alloc_percpu(size, sizeof(void *));
1872 for_each_possible_cpu(cpu) {
1873 init_arraycache(per_cpu_ptr(cpu_cache, cpu),
1874 entries, batchcount);
1880 static int __ref setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
1882 if (slab_state >= FULL)
1883 return enable_cpucache(cachep, gfp);
1885 cachep->cpu_cache = alloc_kmem_cache_cpus(cachep, 1, 1);
1886 if (!cachep->cpu_cache)
1889 if (slab_state == DOWN) {
1890 /* Creation of first cache (kmem_cache). */
1891 set_up_node(kmem_cache, CACHE_CACHE);
1892 } else if (slab_state == PARTIAL) {
1893 /* For kmem_cache_node */
1894 set_up_node(cachep, SIZE_NODE);
1898 for_each_online_node(node) {
1899 cachep->node[node] = kmalloc_node(
1900 sizeof(struct kmem_cache_node), gfp, node);
1901 BUG_ON(!cachep->node[node]);
1902 kmem_cache_node_init(cachep->node[node]);
1906 cachep->node[numa_mem_id()]->next_reap =
1907 jiffies + REAPTIMEOUT_NODE +
1908 ((unsigned long)cachep) % REAPTIMEOUT_NODE;
1910 cpu_cache_get(cachep)->avail = 0;
1911 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
1912 cpu_cache_get(cachep)->batchcount = 1;
1913 cpu_cache_get(cachep)->touched = 0;
1914 cachep->batchcount = 1;
1915 cachep->limit = BOOT_CPUCACHE_ENTRIES;
1919 unsigned long kmem_cache_flags(unsigned long object_size,
1920 unsigned long flags, const char *name,
1921 void (*ctor)(void *))
1927 __kmem_cache_alias(const char *name, size_t size, size_t align,
1928 unsigned long flags, void (*ctor)(void *))
1930 struct kmem_cache *cachep;
1932 cachep = find_mergeable(size, align, flags, name, ctor);
1937 * Adjust the object sizes so that we clear
1938 * the complete object on kzalloc.
1940 cachep->object_size = max_t(int, cachep->object_size, size);
1945 static bool set_objfreelist_slab_cache(struct kmem_cache *cachep,
1946 size_t size, unsigned long flags)
1952 if (cachep->ctor || flags & SLAB_DESTROY_BY_RCU)
1955 left = calculate_slab_order(cachep, size,
1956 flags | CFLGS_OBJFREELIST_SLAB);
1960 if (cachep->num * sizeof(freelist_idx_t) > cachep->object_size)
1963 cachep->colour = left / cachep->colour_off;
1968 static bool set_off_slab_cache(struct kmem_cache *cachep,
1969 size_t size, unsigned long flags)
1976 * Always use on-slab management when SLAB_NOLEAKTRACE
1977 * to avoid recursive calls into kmemleak.
1979 if (flags & SLAB_NOLEAKTRACE)
1983 * Size is large, assume best to place the slab management obj
1984 * off-slab (should allow better packing of objs).
1986 left = calculate_slab_order(cachep, size, flags | CFLGS_OFF_SLAB);
1991 * If the slab has been placed off-slab, and we have enough space then
1992 * move it on-slab. This is at the expense of any extra colouring.
1994 if (left >= cachep->num * sizeof(freelist_idx_t))
1997 cachep->colour = left / cachep->colour_off;
2002 static bool set_on_slab_cache(struct kmem_cache *cachep,
2003 size_t size, unsigned long flags)
2009 left = calculate_slab_order(cachep, size, flags);
2013 cachep->colour = left / cachep->colour_off;
2019 * __kmem_cache_create - Create a cache.
2020 * @cachep: cache management descriptor
2021 * @flags: SLAB flags
2023 * Returns a ptr to the cache on success, NULL on failure.
2024 * Cannot be called within a int, but can be interrupted.
2025 * The @ctor is run when new pages are allocated by the cache.
2029 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2030 * to catch references to uninitialised memory.
2032 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2033 * for buffer overruns.
2035 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2036 * cacheline. This can be beneficial if you're counting cycles as closely
2040 __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
2042 size_t ralign = BYTES_PER_WORD;
2045 size_t size = cachep->size;
2050 * Enable redzoning and last user accounting, except for caches with
2051 * large objects, if the increased size would increase the object size
2052 * above the next power of two: caches with object sizes just above a
2053 * power of two have a significant amount of internal fragmentation.
2055 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2056 2 * sizeof(unsigned long long)))
2057 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2058 if (!(flags & SLAB_DESTROY_BY_RCU))
2059 flags |= SLAB_POISON;
2064 * Check that size is in terms of words. This is needed to avoid
2065 * unaligned accesses for some archs when redzoning is used, and makes
2066 * sure any on-slab bufctl's are also correctly aligned.
2068 if (size & (BYTES_PER_WORD - 1)) {
2069 size += (BYTES_PER_WORD - 1);
2070 size &= ~(BYTES_PER_WORD - 1);
2073 if (flags & SLAB_RED_ZONE) {
2074 ralign = REDZONE_ALIGN;
2075 /* If redzoning, ensure that the second redzone is suitably
2076 * aligned, by adjusting the object size accordingly. */
2077 size += REDZONE_ALIGN - 1;
2078 size &= ~(REDZONE_ALIGN - 1);
2081 /* 3) caller mandated alignment */
2082 if (ralign < cachep->align) {
2083 ralign = cachep->align;
2085 /* disable debug if necessary */
2086 if (ralign > __alignof__(unsigned long long))
2087 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2091 cachep->align = ralign;
2092 cachep->colour_off = cache_line_size();
2093 /* Offset must be a multiple of the alignment. */
2094 if (cachep->colour_off < cachep->align)
2095 cachep->colour_off = cachep->align;
2097 if (slab_is_available())
2105 * Both debugging options require word-alignment which is calculated
2108 if (flags & SLAB_RED_ZONE) {
2109 /* add space for red zone words */
2110 cachep->obj_offset += sizeof(unsigned long long);
2111 size += 2 * sizeof(unsigned long long);
2113 if (flags & SLAB_STORE_USER) {
2114 /* user store requires one word storage behind the end of
2115 * the real object. But if the second red zone needs to be
2116 * aligned to 64 bits, we must allow that much space.
2118 if (flags & SLAB_RED_ZONE)
2119 size += REDZONE_ALIGN;
2121 size += BYTES_PER_WORD;
2125 kasan_cache_create(cachep, &size, &flags);
2127 size = ALIGN(size, cachep->align);
2129 * We should restrict the number of objects in a slab to implement
2130 * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition.
2132 if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE)
2133 size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align);
2137 * To activate debug pagealloc, off-slab management is necessary
2138 * requirement. In early phase of initialization, small sized slab
2139 * doesn't get initialized so it would not be possible. So, we need
2140 * to check size >= 256. It guarantees that all necessary small
2141 * sized slab is initialized in current slab initialization sequence.
2143 if (debug_pagealloc_enabled() && (flags & SLAB_POISON) &&
2144 size >= 256 && cachep->object_size > cache_line_size()) {
2145 if (size < PAGE_SIZE || size % PAGE_SIZE == 0) {
2146 size_t tmp_size = ALIGN(size, PAGE_SIZE);
2148 if (set_off_slab_cache(cachep, tmp_size, flags)) {
2149 flags |= CFLGS_OFF_SLAB;
2150 cachep->obj_offset += tmp_size - size;
2158 if (set_objfreelist_slab_cache(cachep, size, flags)) {
2159 flags |= CFLGS_OBJFREELIST_SLAB;
2163 if (set_off_slab_cache(cachep, size, flags)) {
2164 flags |= CFLGS_OFF_SLAB;
2168 if (set_on_slab_cache(cachep, size, flags))
2174 cachep->freelist_size = cachep->num * sizeof(freelist_idx_t);
2175 cachep->flags = flags;
2176 cachep->allocflags = __GFP_COMP;
2177 if (flags & SLAB_CACHE_DMA)
2178 cachep->allocflags |= GFP_DMA;
2179 cachep->size = size;
2180 cachep->reciprocal_buffer_size = reciprocal_value(size);
2184 * If we're going to use the generic kernel_map_pages()
2185 * poisoning, then it's going to smash the contents of
2186 * the redzone and userword anyhow, so switch them off.
2188 if (IS_ENABLED(CONFIG_PAGE_POISONING) &&
2189 (cachep->flags & SLAB_POISON) &&
2190 is_debug_pagealloc_cache(cachep))
2191 cachep->flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2194 if (OFF_SLAB(cachep)) {
2195 cachep->freelist_cache =
2196 kmalloc_slab(cachep->freelist_size, 0u);
2199 err = setup_cpu_cache(cachep, gfp);
2201 __kmem_cache_release(cachep);
2209 static void check_irq_off(void)
2211 BUG_ON(!irqs_disabled());
2214 static void check_irq_on(void)
2216 BUG_ON(irqs_disabled());
2219 static void check_mutex_acquired(void)
2221 BUG_ON(!mutex_is_locked(&slab_mutex));
2224 static void check_spinlock_acquired(struct kmem_cache *cachep)
2228 assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock);
2232 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2236 assert_spin_locked(&get_node(cachep, node)->list_lock);
2241 #define check_irq_off() do { } while(0)
2242 #define check_irq_on() do { } while(0)
2243 #define check_mutex_acquired() do { } while(0)
2244 #define check_spinlock_acquired(x) do { } while(0)
2245 #define check_spinlock_acquired_node(x, y) do { } while(0)
2248 static void drain_array_locked(struct kmem_cache *cachep, struct array_cache *ac,
2249 int node, bool free_all, struct list_head *list)
2253 if (!ac || !ac->avail)
2256 tofree = free_all ? ac->avail : (ac->limit + 4) / 5;
2257 if (tofree > ac->avail)
2258 tofree = (ac->avail + 1) / 2;
2260 free_block(cachep, ac->entry, tofree, node, list);
2261 ac->avail -= tofree;
2262 memmove(ac->entry, &(ac->entry[tofree]), sizeof(void *) * ac->avail);
2265 static void do_drain(void *arg)
2267 struct kmem_cache *cachep = arg;
2268 struct array_cache *ac;
2269 int node = numa_mem_id();
2270 struct kmem_cache_node *n;
2274 ac = cpu_cache_get(cachep);
2275 n = get_node(cachep, node);
2276 spin_lock(&n->list_lock);
2277 free_block(cachep, ac->entry, ac->avail, node, &list);
2278 spin_unlock(&n->list_lock);
2279 slabs_destroy(cachep, &list);
2283 static void drain_cpu_caches(struct kmem_cache *cachep)
2285 struct kmem_cache_node *n;
2289 on_each_cpu(do_drain, cachep, 1);
2291 for_each_kmem_cache_node(cachep, node, n)
2293 drain_alien_cache(cachep, n->alien);
2295 for_each_kmem_cache_node(cachep, node, n) {
2296 spin_lock_irq(&n->list_lock);
2297 drain_array_locked(cachep, n->shared, node, true, &list);
2298 spin_unlock_irq(&n->list_lock);
2300 slabs_destroy(cachep, &list);
2305 * Remove slabs from the list of free slabs.
2306 * Specify the number of slabs to drain in tofree.
2308 * Returns the actual number of slabs released.
2310 static int drain_freelist(struct kmem_cache *cache,
2311 struct kmem_cache_node *n, int tofree)
2313 struct list_head *p;
2318 while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
2320 spin_lock_irq(&n->list_lock);
2321 p = n->slabs_free.prev;
2322 if (p == &n->slabs_free) {
2323 spin_unlock_irq(&n->list_lock);
2327 page = list_entry(p, struct page, lru);
2328 list_del(&page->lru);
2330 * Safe to drop the lock. The slab is no longer linked
2333 n->free_objects -= cache->num;
2334 spin_unlock_irq(&n->list_lock);
2335 slab_destroy(cache, page);
2342 int __kmem_cache_shrink(struct kmem_cache *cachep, bool deactivate)
2346 struct kmem_cache_node *n;
2348 drain_cpu_caches(cachep);
2351 for_each_kmem_cache_node(cachep, node, n) {
2352 drain_freelist(cachep, n, INT_MAX);
2354 ret += !list_empty(&n->slabs_full) ||
2355 !list_empty(&n->slabs_partial);
2357 return (ret ? 1 : 0);
2360 int __kmem_cache_shutdown(struct kmem_cache *cachep)
2362 return __kmem_cache_shrink(cachep, false);
2365 void __kmem_cache_release(struct kmem_cache *cachep)
2368 struct kmem_cache_node *n;
2370 cache_random_seq_destroy(cachep);
2372 free_percpu(cachep->cpu_cache);
2374 /* NUMA: free the node structures */
2375 for_each_kmem_cache_node(cachep, i, n) {
2377 free_alien_cache(n->alien);
2379 cachep->node[i] = NULL;
2384 * Get the memory for a slab management obj.
2386 * For a slab cache when the slab descriptor is off-slab, the
2387 * slab descriptor can't come from the same cache which is being created,
2388 * Because if it is the case, that means we defer the creation of
2389 * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point.
2390 * And we eventually call down to __kmem_cache_create(), which
2391 * in turn looks up in the kmalloc_{dma,}_caches for the disired-size one.
2392 * This is a "chicken-and-egg" problem.
2394 * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches,
2395 * which are all initialized during kmem_cache_init().
2397 static void *alloc_slabmgmt(struct kmem_cache *cachep,
2398 struct page *page, int colour_off,
2399 gfp_t local_flags, int nodeid)
2402 void *addr = page_address(page);
2404 page->s_mem = addr + colour_off;
2407 if (OBJFREELIST_SLAB(cachep))
2409 else if (OFF_SLAB(cachep)) {
2410 /* Slab management obj is off-slab. */
2411 freelist = kmem_cache_alloc_node(cachep->freelist_cache,
2412 local_flags, nodeid);
2416 /* We will use last bytes at the slab for freelist */
2417 freelist = addr + (PAGE_SIZE << cachep->gfporder) -
2418 cachep->freelist_size;
2424 static inline freelist_idx_t get_free_obj(struct page *page, unsigned int idx)
2426 return ((freelist_idx_t *)page->freelist)[idx];
2429 static inline void set_free_obj(struct page *page,
2430 unsigned int idx, freelist_idx_t val)
2432 ((freelist_idx_t *)(page->freelist))[idx] = val;
2435 static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page)
2440 for (i = 0; i < cachep->num; i++) {
2441 void *objp = index_to_obj(cachep, page, i);
2443 if (cachep->flags & SLAB_STORE_USER)
2444 *dbg_userword(cachep, objp) = NULL;
2446 if (cachep->flags & SLAB_RED_ZONE) {
2447 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2448 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2451 * Constructors are not allowed to allocate memory from the same
2452 * cache which they are a constructor for. Otherwise, deadlock.
2453 * They must also be threaded.
2455 if (cachep->ctor && !(cachep->flags & SLAB_POISON)) {
2456 kasan_unpoison_object_data(cachep,
2457 objp + obj_offset(cachep));
2458 cachep->ctor(objp + obj_offset(cachep));
2459 kasan_poison_object_data(
2460 cachep, objp + obj_offset(cachep));
2463 if (cachep->flags & SLAB_RED_ZONE) {
2464 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2465 slab_error(cachep, "constructor overwrote the end of an object");
2466 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2467 slab_error(cachep, "constructor overwrote the start of an object");
2469 /* need to poison the objs? */
2470 if (cachep->flags & SLAB_POISON) {
2471 poison_obj(cachep, objp, POISON_FREE);
2472 slab_kernel_map(cachep, objp, 0, 0);
2478 #ifdef CONFIG_SLAB_FREELIST_RANDOM
2479 /* Hold information during a freelist initialization */
2480 union freelist_init_state {
2487 struct rnd_state rnd_state;
2491 * Initialize the state based on the randomization methode available.
2492 * return true if the pre-computed list is available, false otherwize.
2494 static bool freelist_state_initialize(union freelist_init_state *state,
2495 struct kmem_cache *cachep,
2501 /* Use best entropy available to define a random shift */
2502 rand = get_random_int();
2504 /* Use a random state if the pre-computed list is not available */
2505 if (!cachep->random_seq) {
2506 prandom_seed_state(&state->rnd_state, rand);
2509 state->list = cachep->random_seq;
2510 state->count = count;
2518 /* Get the next entry on the list and randomize it using a random shift */
2519 static freelist_idx_t next_random_slot(union freelist_init_state *state)
2521 return (state->list[state->pos++] + state->rand) % state->count;
2524 /* Swap two freelist entries */
2525 static void swap_free_obj(struct page *page, unsigned int a, unsigned int b)
2527 swap(((freelist_idx_t *)page->freelist)[a],
2528 ((freelist_idx_t *)page->freelist)[b]);
2532 * Shuffle the freelist initialization state based on pre-computed lists.
2533 * return true if the list was successfully shuffled, false otherwise.
2535 static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page)
2537 unsigned int objfreelist = 0, i, rand, count = cachep->num;
2538 union freelist_init_state state;
2544 precomputed = freelist_state_initialize(&state, cachep, count);
2546 /* Take a random entry as the objfreelist */
2547 if (OBJFREELIST_SLAB(cachep)) {
2549 objfreelist = count - 1;
2551 objfreelist = next_random_slot(&state);
2552 page->freelist = index_to_obj(cachep, page, objfreelist) +
2558 * On early boot, generate the list dynamically.
2559 * Later use a pre-computed list for speed.
2562 for (i = 0; i < count; i++)
2563 set_free_obj(page, i, i);
2565 /* Fisher-Yates shuffle */
2566 for (i = count - 1; i > 0; i--) {
2567 rand = prandom_u32_state(&state.rnd_state);
2569 swap_free_obj(page, i, rand);
2572 for (i = 0; i < count; i++)
2573 set_free_obj(page, i, next_random_slot(&state));
2576 if (OBJFREELIST_SLAB(cachep))
2577 set_free_obj(page, cachep->num - 1, objfreelist);
2582 static inline bool shuffle_freelist(struct kmem_cache *cachep,
2587 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
2589 static void cache_init_objs(struct kmem_cache *cachep,
2596 cache_init_objs_debug(cachep, page);
2598 /* Try to randomize the freelist if enabled */
2599 shuffled = shuffle_freelist(cachep, page);
2601 if (!shuffled && OBJFREELIST_SLAB(cachep)) {
2602 page->freelist = index_to_obj(cachep, page, cachep->num - 1) +
2606 for (i = 0; i < cachep->num; i++) {
2607 objp = index_to_obj(cachep, page, i);
2608 kasan_init_slab_obj(cachep, objp);
2610 /* constructor could break poison info */
2611 if (DEBUG == 0 && cachep->ctor) {
2612 kasan_unpoison_object_data(cachep, objp);
2614 kasan_poison_object_data(cachep, objp);
2618 set_free_obj(page, i, i);
2622 static void *slab_get_obj(struct kmem_cache *cachep, struct page *page)
2626 objp = index_to_obj(cachep, page, get_free_obj(page, page->active));
2630 if (cachep->flags & SLAB_STORE_USER)
2631 set_store_user_dirty(cachep);
2637 static void slab_put_obj(struct kmem_cache *cachep,
2638 struct page *page, void *objp)
2640 unsigned int objnr = obj_to_index(cachep, page, objp);
2644 /* Verify double free bug */
2645 for (i = page->active; i < cachep->num; i++) {
2646 if (get_free_obj(page, i) == objnr) {
2647 pr_err("slab: double free detected in cache '%s', objp %p\n",
2648 cachep->name, objp);
2654 if (!page->freelist)
2655 page->freelist = objp + obj_offset(cachep);
2657 set_free_obj(page, page->active, objnr);
2661 * Map pages beginning at addr to the given cache and slab. This is required
2662 * for the slab allocator to be able to lookup the cache and slab of a
2663 * virtual address for kfree, ksize, and slab debugging.
2665 static void slab_map_pages(struct kmem_cache *cache, struct page *page,
2668 page->slab_cache = cache;
2669 page->freelist = freelist;
2673 * Grow (by 1) the number of slabs within a cache. This is called by
2674 * kmem_cache_alloc() when there are no active objs left in a cache.
2676 static struct page *cache_grow_begin(struct kmem_cache *cachep,
2677 gfp_t flags, int nodeid)
2683 struct kmem_cache_node *n;
2687 * Be lazy and only check for valid flags here, keeping it out of the
2688 * critical path in kmem_cache_alloc().
2690 if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
2691 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
2692 flags &= ~GFP_SLAB_BUG_MASK;
2693 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
2694 invalid_mask, &invalid_mask, flags, &flags);
2697 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2700 if (gfpflags_allow_blocking(local_flags))
2704 * Get mem for the objs. Attempt to allocate a physical page from
2707 page = kmem_getpages(cachep, local_flags, nodeid);
2711 page_node = page_to_nid(page);
2712 n = get_node(cachep, page_node);
2714 /* Get colour for the slab, and cal the next value. */
2716 if (n->colour_next >= cachep->colour)
2719 offset = n->colour_next;
2720 if (offset >= cachep->colour)
2723 offset *= cachep->colour_off;
2725 /* Get slab management. */
2726 freelist = alloc_slabmgmt(cachep, page, offset,
2727 local_flags & ~GFP_CONSTRAINT_MASK, page_node);
2728 if (OFF_SLAB(cachep) && !freelist)
2731 slab_map_pages(cachep, page, freelist);
2733 kasan_poison_slab(page);
2734 cache_init_objs(cachep, page);
2736 if (gfpflags_allow_blocking(local_flags))
2737 local_irq_disable();
2742 kmem_freepages(cachep, page);
2744 if (gfpflags_allow_blocking(local_flags))
2745 local_irq_disable();
2749 static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
2751 struct kmem_cache_node *n;
2759 INIT_LIST_HEAD(&page->lru);
2760 n = get_node(cachep, page_to_nid(page));
2762 spin_lock(&n->list_lock);
2764 list_add_tail(&page->lru, &(n->slabs_free));
2766 fixup_slab_list(cachep, n, page, &list);
2767 STATS_INC_GROWN(cachep);
2768 n->free_objects += cachep->num - page->active;
2769 spin_unlock(&n->list_lock);
2771 fixup_objfreelist_debug(cachep, &list);
2777 * Perform extra freeing checks:
2778 * - detect bad pointers.
2779 * - POISON/RED_ZONE checking
2781 static void kfree_debugcheck(const void *objp)
2783 if (!virt_addr_valid(objp)) {
2784 pr_err("kfree_debugcheck: out of range ptr %lxh\n",
2785 (unsigned long)objp);
2790 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2792 unsigned long long redzone1, redzone2;
2794 redzone1 = *dbg_redzone1(cache, obj);
2795 redzone2 = *dbg_redzone2(cache, obj);
2800 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2803 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2804 slab_error(cache, "double free detected");
2806 slab_error(cache, "memory outside object was overwritten");
2808 pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
2809 obj, redzone1, redzone2);
2812 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2813 unsigned long caller)
2818 BUG_ON(virt_to_cache(objp) != cachep);
2820 objp -= obj_offset(cachep);
2821 kfree_debugcheck(objp);
2822 page = virt_to_head_page(objp);
2824 if (cachep->flags & SLAB_RED_ZONE) {
2825 verify_redzone_free(cachep, objp);
2826 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2827 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2829 if (cachep->flags & SLAB_STORE_USER) {
2830 set_store_user_dirty(cachep);
2831 *dbg_userword(cachep, objp) = (void *)caller;
2834 objnr = obj_to_index(cachep, page, objp);
2836 BUG_ON(objnr >= cachep->num);
2837 BUG_ON(objp != index_to_obj(cachep, page, objnr));
2839 if (cachep->flags & SLAB_POISON) {
2840 poison_obj(cachep, objp, POISON_FREE);
2841 slab_kernel_map(cachep, objp, 0, caller);
2847 #define kfree_debugcheck(x) do { } while(0)
2848 #define cache_free_debugcheck(x,objp,z) (objp)
2851 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
2859 objp = next - obj_offset(cachep);
2860 next = *(void **)next;
2861 poison_obj(cachep, objp, POISON_FREE);
2866 static inline void fixup_slab_list(struct kmem_cache *cachep,
2867 struct kmem_cache_node *n, struct page *page,
2870 /* move slabp to correct slabp list: */
2871 list_del(&page->lru);
2872 if (page->active == cachep->num) {
2873 list_add(&page->lru, &n->slabs_full);
2874 if (OBJFREELIST_SLAB(cachep)) {
2876 /* Poisoning will be done without holding the lock */
2877 if (cachep->flags & SLAB_POISON) {
2878 void **objp = page->freelist;
2884 page->freelist = NULL;
2887 list_add(&page->lru, &n->slabs_partial);
2890 /* Try to find non-pfmemalloc slab if needed */
2891 static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n,
2892 struct page *page, bool pfmemalloc)
2900 if (!PageSlabPfmemalloc(page))
2903 /* No need to keep pfmemalloc slab if we have enough free objects */
2904 if (n->free_objects > n->free_limit) {
2905 ClearPageSlabPfmemalloc(page);
2909 /* Move pfmemalloc slab to the end of list to speed up next search */
2910 list_del(&page->lru);
2912 list_add_tail(&page->lru, &n->slabs_free);
2914 list_add_tail(&page->lru, &n->slabs_partial);
2916 list_for_each_entry(page, &n->slabs_partial, lru) {
2917 if (!PageSlabPfmemalloc(page))
2921 list_for_each_entry(page, &n->slabs_free, lru) {
2922 if (!PageSlabPfmemalloc(page))
2929 static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
2933 page = list_first_entry_or_null(&n->slabs_partial,
2936 n->free_touched = 1;
2937 page = list_first_entry_or_null(&n->slabs_free,
2941 if (sk_memalloc_socks())
2942 return get_valid_first_slab(n, page, pfmemalloc);
2947 static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
2948 struct kmem_cache_node *n, gfp_t flags)
2954 if (!gfp_pfmemalloc_allowed(flags))
2957 spin_lock(&n->list_lock);
2958 page = get_first_slab(n, true);
2960 spin_unlock(&n->list_lock);
2964 obj = slab_get_obj(cachep, page);
2967 fixup_slab_list(cachep, n, page, &list);
2969 spin_unlock(&n->list_lock);
2970 fixup_objfreelist_debug(cachep, &list);
2976 * Slab list should be fixed up by fixup_slab_list() for existing slab
2977 * or cache_grow_end() for new slab
2979 static __always_inline int alloc_block(struct kmem_cache *cachep,
2980 struct array_cache *ac, struct page *page, int batchcount)
2983 * There must be at least one object available for
2986 BUG_ON(page->active >= cachep->num);
2988 while (page->active < cachep->num && batchcount--) {
2989 STATS_INC_ALLOCED(cachep);
2990 STATS_INC_ACTIVE(cachep);
2991 STATS_SET_HIGH(cachep);
2993 ac->entry[ac->avail++] = slab_get_obj(cachep, page);
2999 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
3002 struct kmem_cache_node *n;
3003 struct array_cache *ac, *shared;
3009 node = numa_mem_id();
3011 ac = cpu_cache_get(cachep);
3012 batchcount = ac->batchcount;
3013 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
3015 * If there was little recent activity on this cache, then
3016 * perform only a partial refill. Otherwise we could generate
3019 batchcount = BATCHREFILL_LIMIT;
3021 n = get_node(cachep, node);
3023 BUG_ON(ac->avail > 0 || !n);
3024 shared = READ_ONCE(n->shared);
3025 if (!n->free_objects && (!shared || !shared->avail))
3028 spin_lock(&n->list_lock);
3029 shared = READ_ONCE(n->shared);
3031 /* See if we can refill from the shared array */
3032 if (shared && transfer_objects(ac, shared, batchcount)) {
3033 shared->touched = 1;
3037 while (batchcount > 0) {
3038 /* Get slab alloc is to come from. */
3039 page = get_first_slab(n, false);
3043 check_spinlock_acquired(cachep);
3045 batchcount = alloc_block(cachep, ac, page, batchcount);
3046 fixup_slab_list(cachep, n, page, &list);
3050 n->free_objects -= ac->avail;
3052 spin_unlock(&n->list_lock);
3053 fixup_objfreelist_debug(cachep, &list);
3056 if (unlikely(!ac->avail)) {
3057 /* Check if we can use obj in pfmemalloc slab */
3058 if (sk_memalloc_socks()) {
3059 void *obj = cache_alloc_pfmemalloc(cachep, n, flags);
3065 page = cache_grow_begin(cachep, gfp_exact_node(flags), node);
3068 * cache_grow_begin() can reenable interrupts,
3069 * then ac could change.
3071 ac = cpu_cache_get(cachep);
3072 if (!ac->avail && page)
3073 alloc_block(cachep, ac, page, batchcount);
3074 cache_grow_end(cachep, page);
3081 return ac->entry[--ac->avail];
3084 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
3087 might_sleep_if(gfpflags_allow_blocking(flags));
3091 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
3092 gfp_t flags, void *objp, unsigned long caller)
3096 if (cachep->flags & SLAB_POISON) {
3097 check_poison_obj(cachep, objp);
3098 slab_kernel_map(cachep, objp, 1, 0);
3099 poison_obj(cachep, objp, POISON_INUSE);
3101 if (cachep->flags & SLAB_STORE_USER)
3102 *dbg_userword(cachep, objp) = (void *)caller;
3104 if (cachep->flags & SLAB_RED_ZONE) {
3105 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
3106 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
3107 slab_error(cachep, "double free, or memory outside object was overwritten");
3108 pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3109 objp, *dbg_redzone1(cachep, objp),
3110 *dbg_redzone2(cachep, objp));
3112 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
3113 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
3116 objp += obj_offset(cachep);
3117 if (cachep->ctor && cachep->flags & SLAB_POISON)
3119 if (ARCH_SLAB_MINALIGN &&
3120 ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
3121 pr_err("0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3122 objp, (int)ARCH_SLAB_MINALIGN);
3127 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3130 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3133 struct array_cache *ac;
3137 ac = cpu_cache_get(cachep);
3138 if (likely(ac->avail)) {
3140 objp = ac->entry[--ac->avail];
3142 STATS_INC_ALLOCHIT(cachep);
3146 STATS_INC_ALLOCMISS(cachep);
3147 objp = cache_alloc_refill(cachep, flags);
3149 * the 'ac' may be updated by cache_alloc_refill(),
3150 * and kmemleak_erase() requires its correct value.
3152 ac = cpu_cache_get(cachep);
3156 * To avoid a false negative, if an object that is in one of the
3157 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3158 * treat the array pointers as a reference to the object.
3161 kmemleak_erase(&ac->entry[ac->avail]);
3167 * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set.
3169 * If we are in_interrupt, then process context, including cpusets and
3170 * mempolicy, may not apply and should not be used for allocation policy.
3172 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3174 int nid_alloc, nid_here;
3176 if (in_interrupt() || (flags & __GFP_THISNODE))
3178 nid_alloc = nid_here = numa_mem_id();
3179 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3180 nid_alloc = cpuset_slab_spread_node();
3181 else if (current->mempolicy)
3182 nid_alloc = mempolicy_slab_node();
3183 if (nid_alloc != nid_here)
3184 return ____cache_alloc_node(cachep, flags, nid_alloc);
3189 * Fallback function if there was no memory available and no objects on a
3190 * certain node and fall back is permitted. First we scan all the
3191 * available node for available objects. If that fails then we
3192 * perform an allocation without specifying a node. This allows the page
3193 * allocator to do its reclaim / fallback magic. We then insert the
3194 * slab into the proper nodelist and then allocate from it.
3196 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3198 struct zonelist *zonelist;
3201 enum zone_type high_zoneidx = gfp_zone(flags);
3205 unsigned int cpuset_mems_cookie;
3207 if (flags & __GFP_THISNODE)
3211 cpuset_mems_cookie = read_mems_allowed_begin();
3212 zonelist = node_zonelist(mempolicy_slab_node(), flags);
3216 * Look through allowed nodes for objects available
3217 * from existing per node queues.
3219 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3220 nid = zone_to_nid(zone);
3222 if (cpuset_zone_allowed(zone, flags) &&
3223 get_node(cache, nid) &&
3224 get_node(cache, nid)->free_objects) {
3225 obj = ____cache_alloc_node(cache,
3226 gfp_exact_node(flags), nid);
3234 * This allocation will be performed within the constraints
3235 * of the current cpuset / memory policy requirements.
3236 * We may trigger various forms of reclaim on the allowed
3237 * set and go into memory reserves if necessary.
3239 page = cache_grow_begin(cache, flags, numa_mem_id());
3240 cache_grow_end(cache, page);
3242 nid = page_to_nid(page);
3243 obj = ____cache_alloc_node(cache,
3244 gfp_exact_node(flags), nid);
3247 * Another processor may allocate the objects in
3248 * the slab since we are not holding any locks.
3255 if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie)))
3261 * A interface to enable slab creation on nodeid
3263 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3267 struct kmem_cache_node *n;
3271 VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES);
3272 n = get_node(cachep, nodeid);
3276 spin_lock(&n->list_lock);
3277 page = get_first_slab(n, false);
3281 check_spinlock_acquired_node(cachep, nodeid);
3283 STATS_INC_NODEALLOCS(cachep);
3284 STATS_INC_ACTIVE(cachep);
3285 STATS_SET_HIGH(cachep);
3287 BUG_ON(page->active == cachep->num);
3289 obj = slab_get_obj(cachep, page);
3292 fixup_slab_list(cachep, n, page, &list);
3294 spin_unlock(&n->list_lock);
3295 fixup_objfreelist_debug(cachep, &list);
3299 spin_unlock(&n->list_lock);
3300 page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid);
3302 /* This slab isn't counted yet so don't update free_objects */
3303 obj = slab_get_obj(cachep, page);
3305 cache_grow_end(cachep, page);
3307 return obj ? obj : fallback_alloc(cachep, flags);
3310 static __always_inline void *
3311 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3312 unsigned long caller)
3314 unsigned long save_flags;
3316 int slab_node = numa_mem_id();
3318 flags &= gfp_allowed_mask;
3319 cachep = slab_pre_alloc_hook(cachep, flags);
3320 if (unlikely(!cachep))
3323 cache_alloc_debugcheck_before(cachep, flags);
3324 local_irq_save(save_flags);
3326 if (nodeid == NUMA_NO_NODE)
3329 if (unlikely(!get_node(cachep, nodeid))) {
3330 /* Node not bootstrapped yet */
3331 ptr = fallback_alloc(cachep, flags);
3335 if (nodeid == slab_node) {
3337 * Use the locally cached objects if possible.
3338 * However ____cache_alloc does not allow fallback
3339 * to other nodes. It may fail while we still have
3340 * objects on other nodes available.
3342 ptr = ____cache_alloc(cachep, flags);
3346 /* ___cache_alloc_node can fall back to other nodes */
3347 ptr = ____cache_alloc_node(cachep, flags, nodeid);
3349 local_irq_restore(save_flags);
3350 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3352 if (unlikely(flags & __GFP_ZERO) && ptr)
3353 memset(ptr, 0, cachep->object_size);
3355 slab_post_alloc_hook(cachep, flags, 1, &ptr);
3359 static __always_inline void *
3360 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3364 if (current->mempolicy || cpuset_do_slab_mem_spread()) {
3365 objp = alternate_node_alloc(cache, flags);
3369 objp = ____cache_alloc(cache, flags);
3372 * We may just have run out of memory on the local node.
3373 * ____cache_alloc_node() knows how to locate memory on other nodes
3376 objp = ____cache_alloc_node(cache, flags, numa_mem_id());
3383 static __always_inline void *
3384 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3386 return ____cache_alloc(cachep, flags);
3389 #endif /* CONFIG_NUMA */
3391 static __always_inline void *
3392 slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
3394 unsigned long save_flags;
3397 flags &= gfp_allowed_mask;
3398 cachep = slab_pre_alloc_hook(cachep, flags);
3399 if (unlikely(!cachep))
3402 cache_alloc_debugcheck_before(cachep, flags);
3403 local_irq_save(save_flags);
3404 objp = __do_cache_alloc(cachep, flags);
3405 local_irq_restore(save_flags);
3406 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3409 if (unlikely(flags & __GFP_ZERO) && objp)
3410 memset(objp, 0, cachep->object_size);
3412 slab_post_alloc_hook(cachep, flags, 1, &objp);
3417 * Caller needs to acquire correct kmem_cache_node's list_lock
3418 * @list: List of detached free slabs should be freed by caller
3420 static void free_block(struct kmem_cache *cachep, void **objpp,
3421 int nr_objects, int node, struct list_head *list)
3424 struct kmem_cache_node *n = get_node(cachep, node);
3427 n->free_objects += nr_objects;
3429 for (i = 0; i < nr_objects; i++) {
3435 page = virt_to_head_page(objp);
3436 list_del(&page->lru);
3437 check_spinlock_acquired_node(cachep, node);
3438 slab_put_obj(cachep, page, objp);
3439 STATS_DEC_ACTIVE(cachep);
3441 /* fixup slab chains */
3442 if (page->active == 0)
3443 list_add(&page->lru, &n->slabs_free);
3445 /* Unconditionally move a slab to the end of the
3446 * partial list on free - maximum time for the
3447 * other objects to be freed, too.
3449 list_add_tail(&page->lru, &n->slabs_partial);
3453 while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) {
3454 n->free_objects -= cachep->num;
3456 page = list_last_entry(&n->slabs_free, struct page, lru);
3457 list_move(&page->lru, list);
3461 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3464 struct kmem_cache_node *n;
3465 int node = numa_mem_id();
3468 batchcount = ac->batchcount;
3471 n = get_node(cachep, node);
3472 spin_lock(&n->list_lock);
3474 struct array_cache *shared_array = n->shared;
3475 int max = shared_array->limit - shared_array->avail;
3477 if (batchcount > max)
3479 memcpy(&(shared_array->entry[shared_array->avail]),
3480 ac->entry, sizeof(void *) * batchcount);
3481 shared_array->avail += batchcount;
3486 free_block(cachep, ac->entry, batchcount, node, &list);
3493 list_for_each_entry(page, &n->slabs_free, lru) {
3494 BUG_ON(page->active);
3498 STATS_SET_FREEABLE(cachep, i);
3501 spin_unlock(&n->list_lock);
3502 slabs_destroy(cachep, &list);
3503 ac->avail -= batchcount;
3504 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3508 * Release an obj back to its cache. If the obj has a constructed state, it must
3509 * be in this state _before_ it is released. Called with disabled ints.
3511 static inline void __cache_free(struct kmem_cache *cachep, void *objp,
3512 unsigned long caller)
3514 /* Put the object into the quarantine, don't touch it for now. */
3515 if (kasan_slab_free(cachep, objp))
3518 ___cache_free(cachep, objp, caller);
3521 void ___cache_free(struct kmem_cache *cachep, void *objp,
3522 unsigned long caller)
3524 struct array_cache *ac = cpu_cache_get(cachep);
3527 kmemleak_free_recursive(objp, cachep->flags);
3528 objp = cache_free_debugcheck(cachep, objp, caller);
3530 kmemcheck_slab_free(cachep, objp, cachep->object_size);
3533 * Skip calling cache_free_alien() when the platform is not numa.
3534 * This will avoid cache misses that happen while accessing slabp (which
3535 * is per page memory reference) to get nodeid. Instead use a global
3536 * variable to skip the call, which is mostly likely to be present in
3539 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3542 if (ac->avail < ac->limit) {
3543 STATS_INC_FREEHIT(cachep);
3545 STATS_INC_FREEMISS(cachep);
3546 cache_flusharray(cachep, ac);
3549 if (sk_memalloc_socks()) {
3550 struct page *page = virt_to_head_page(objp);
3552 if (unlikely(PageSlabPfmemalloc(page))) {
3553 cache_free_pfmemalloc(cachep, page, objp);
3558 ac->entry[ac->avail++] = objp;
3562 * kmem_cache_alloc - Allocate an object
3563 * @cachep: The cache to allocate from.
3564 * @flags: See kmalloc().
3566 * Allocate an object from this cache. The flags are only relevant
3567 * if the cache has no available objects.
3569 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3571 void *ret = slab_alloc(cachep, flags, _RET_IP_);
3573 kasan_slab_alloc(cachep, ret, flags);
3574 trace_kmem_cache_alloc(_RET_IP_, ret,
3575 cachep->object_size, cachep->size, flags);
3579 EXPORT_SYMBOL(kmem_cache_alloc);
3581 static __always_inline void
3582 cache_alloc_debugcheck_after_bulk(struct kmem_cache *s, gfp_t flags,
3583 size_t size, void **p, unsigned long caller)
3587 for (i = 0; i < size; i++)
3588 p[i] = cache_alloc_debugcheck_after(s, flags, p[i], caller);
3591 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3596 s = slab_pre_alloc_hook(s, flags);
3600 cache_alloc_debugcheck_before(s, flags);
3602 local_irq_disable();
3603 for (i = 0; i < size; i++) {
3604 void *objp = __do_cache_alloc(s, flags);
3606 if (unlikely(!objp))
3612 cache_alloc_debugcheck_after_bulk(s, flags, size, p, _RET_IP_);
3614 /* Clear memory outside IRQ disabled section */
3615 if (unlikely(flags & __GFP_ZERO))
3616 for (i = 0; i < size; i++)
3617 memset(p[i], 0, s->object_size);
3619 slab_post_alloc_hook(s, flags, size, p);
3620 /* FIXME: Trace call missing. Christoph would like a bulk variant */
3624 cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_);
3625 slab_post_alloc_hook(s, flags, i, p);
3626 __kmem_cache_free_bulk(s, i, p);
3629 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3631 #ifdef CONFIG_TRACING
3633 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
3637 ret = slab_alloc(cachep, flags, _RET_IP_);
3639 kasan_kmalloc(cachep, ret, size, flags);
3640 trace_kmalloc(_RET_IP_, ret,
3641 size, cachep->size, flags);
3644 EXPORT_SYMBOL(kmem_cache_alloc_trace);
3649 * kmem_cache_alloc_node - Allocate an object on the specified node
3650 * @cachep: The cache to allocate from.
3651 * @flags: See kmalloc().
3652 * @nodeid: node number of the target node.
3654 * Identical to kmem_cache_alloc but it will allocate memory on the given
3655 * node, which can improve the performance for cpu bound structures.
3657 * Fallback to other node is possible if __GFP_THISNODE is not set.
3659 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3661 void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3663 kasan_slab_alloc(cachep, ret, flags);
3664 trace_kmem_cache_alloc_node(_RET_IP_, ret,
3665 cachep->object_size, cachep->size,
3670 EXPORT_SYMBOL(kmem_cache_alloc_node);
3672 #ifdef CONFIG_TRACING
3673 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
3680 ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3682 kasan_kmalloc(cachep, ret, size, flags);
3683 trace_kmalloc_node(_RET_IP_, ret,
3688 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3691 static __always_inline void *
3692 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
3694 struct kmem_cache *cachep;
3697 cachep = kmalloc_slab(size, flags);
3698 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3700 ret = kmem_cache_alloc_node_trace(cachep, flags, node, size);
3701 kasan_kmalloc(cachep, ret, size, flags);
3706 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3708 return __do_kmalloc_node(size, flags, node, _RET_IP_);
3710 EXPORT_SYMBOL(__kmalloc_node);
3712 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3713 int node, unsigned long caller)
3715 return __do_kmalloc_node(size, flags, node, caller);
3717 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3718 #endif /* CONFIG_NUMA */
3721 * __do_kmalloc - allocate memory
3722 * @size: how many bytes of memory are required.
3723 * @flags: the type of memory to allocate (see kmalloc).
3724 * @caller: function caller for debug tracking of the caller
3726 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3727 unsigned long caller)
3729 struct kmem_cache *cachep;
3732 cachep = kmalloc_slab(size, flags);
3733 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3735 ret = slab_alloc(cachep, flags, caller);
3737 kasan_kmalloc(cachep, ret, size, flags);
3738 trace_kmalloc(caller, ret,
3739 size, cachep->size, flags);
3744 void *__kmalloc(size_t size, gfp_t flags)
3746 return __do_kmalloc(size, flags, _RET_IP_);
3748 EXPORT_SYMBOL(__kmalloc);
3750 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3752 return __do_kmalloc(size, flags, caller);
3754 EXPORT_SYMBOL(__kmalloc_track_caller);
3757 * kmem_cache_free - Deallocate an object
3758 * @cachep: The cache the allocation was from.
3759 * @objp: The previously allocated object.
3761 * Free an object which was previously allocated from this
3764 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3766 unsigned long flags;
3767 cachep = cache_from_obj(cachep, objp);
3771 local_irq_save(flags);
3772 debug_check_no_locks_freed(objp, cachep->object_size);
3773 if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3774 debug_check_no_obj_freed(objp, cachep->object_size);
3775 __cache_free(cachep, objp, _RET_IP_);
3776 local_irq_restore(flags);
3778 trace_kmem_cache_free(_RET_IP_, objp);
3780 EXPORT_SYMBOL(kmem_cache_free);
3782 void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p)
3784 struct kmem_cache *s;
3787 local_irq_disable();
3788 for (i = 0; i < size; i++) {
3791 if (!orig_s) /* called via kfree_bulk */
3792 s = virt_to_cache(objp);
3794 s = cache_from_obj(orig_s, objp);
3796 debug_check_no_locks_freed(objp, s->object_size);
3797 if (!(s->flags & SLAB_DEBUG_OBJECTS))
3798 debug_check_no_obj_freed(objp, s->object_size);
3800 __cache_free(s, objp, _RET_IP_);
3804 /* FIXME: add tracing */
3806 EXPORT_SYMBOL(kmem_cache_free_bulk);
3809 * kfree - free previously allocated memory
3810 * @objp: pointer returned by kmalloc.
3812 * If @objp is NULL, no operation is performed.
3814 * Don't free memory not originally allocated by kmalloc()
3815 * or you will run into trouble.
3817 void kfree(const void *objp)
3819 struct kmem_cache *c;
3820 unsigned long flags;
3822 trace_kfree(_RET_IP_, objp);
3824 if (unlikely(ZERO_OR_NULL_PTR(objp)))
3826 local_irq_save(flags);
3827 kfree_debugcheck(objp);
3828 c = virt_to_cache(objp);
3829 debug_check_no_locks_freed(objp, c->object_size);
3831 debug_check_no_obj_freed(objp, c->object_size);
3832 __cache_free(c, (void *)objp, _RET_IP_);
3833 local_irq_restore(flags);
3835 EXPORT_SYMBOL(kfree);
3838 * This initializes kmem_cache_node or resizes various caches for all nodes.
3840 static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp)
3844 struct kmem_cache_node *n;
3846 for_each_online_node(node) {
3847 ret = setup_kmem_cache_node(cachep, node, gfp, true);
3856 if (!cachep->list.next) {
3857 /* Cache is not active yet. Roll back what we did */
3860 n = get_node(cachep, node);
3863 free_alien_cache(n->alien);
3865 cachep->node[node] = NULL;
3873 /* Always called with the slab_mutex held */
3874 static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
3875 int batchcount, int shared, gfp_t gfp)
3877 struct array_cache __percpu *cpu_cache, *prev;
3880 cpu_cache = alloc_kmem_cache_cpus(cachep, limit, batchcount);
3884 prev = cachep->cpu_cache;
3885 cachep->cpu_cache = cpu_cache;
3886 kick_all_cpus_sync();
3889 cachep->batchcount = batchcount;
3890 cachep->limit = limit;
3891 cachep->shared = shared;
3896 for_each_online_cpu(cpu) {
3899 struct kmem_cache_node *n;
3900 struct array_cache *ac = per_cpu_ptr(prev, cpu);
3902 node = cpu_to_mem(cpu);
3903 n = get_node(cachep, node);
3904 spin_lock_irq(&n->list_lock);
3905 free_block(cachep, ac->entry, ac->avail, node, &list);
3906 spin_unlock_irq(&n->list_lock);
3907 slabs_destroy(cachep, &list);
3912 return setup_kmem_cache_nodes(cachep, gfp);
3915 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3916 int batchcount, int shared, gfp_t gfp)
3919 struct kmem_cache *c;
3921 ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3923 if (slab_state < FULL)
3926 if ((ret < 0) || !is_root_cache(cachep))
3929 lockdep_assert_held(&slab_mutex);
3930 for_each_memcg_cache(c, cachep) {
3931 /* return value determined by the root cache only */
3932 __do_tune_cpucache(c, limit, batchcount, shared, gfp);
3938 /* Called with slab_mutex held always */
3939 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3946 err = cache_random_seq_create(cachep, cachep->num, gfp);
3950 if (!is_root_cache(cachep)) {
3951 struct kmem_cache *root = memcg_root_cache(cachep);
3952 limit = root->limit;
3953 shared = root->shared;
3954 batchcount = root->batchcount;
3957 if (limit && shared && batchcount)
3960 * The head array serves three purposes:
3961 * - create a LIFO ordering, i.e. return objects that are cache-warm
3962 * - reduce the number of spinlock operations.
3963 * - reduce the number of linked list operations on the slab and
3964 * bufctl chains: array operations are cheaper.
3965 * The numbers are guessed, we should auto-tune as described by
3968 if (cachep->size > 131072)
3970 else if (cachep->size > PAGE_SIZE)
3972 else if (cachep->size > 1024)
3974 else if (cachep->size > 256)
3980 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3981 * allocation behaviour: Most allocs on one cpu, most free operations
3982 * on another cpu. For these cases, an efficient object passing between
3983 * cpus is necessary. This is provided by a shared array. The array
3984 * replaces Bonwick's magazine layer.
3985 * On uniprocessor, it's functionally equivalent (but less efficient)
3986 * to a larger limit. Thus disabled by default.
3989 if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
3994 * With debugging enabled, large batchcount lead to excessively long
3995 * periods with disabled local interrupts. Limit the batchcount
4000 batchcount = (limit + 1) / 2;
4002 err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
4005 pr_err("enable_cpucache failed for %s, error %d\n",
4006 cachep->name, -err);
4011 * Drain an array if it contains any elements taking the node lock only if
4012 * necessary. Note that the node listlock also protects the array_cache
4013 * if drain_array() is used on the shared array.
4015 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
4016 struct array_cache *ac, int node)
4020 /* ac from n->shared can be freed if we don't hold the slab_mutex. */
4021 check_mutex_acquired();
4023 if (!ac || !ac->avail)
4031 spin_lock_irq(&n->list_lock);
4032 drain_array_locked(cachep, ac, node, false, &list);
4033 spin_unlock_irq(&n->list_lock);
4035 slabs_destroy(cachep, &list);
4039 * cache_reap - Reclaim memory from caches.
4040 * @w: work descriptor
4042 * Called from workqueue/eventd every few seconds.
4044 * - clear the per-cpu caches for this CPU.
4045 * - return freeable pages to the main free memory pool.
4047 * If we cannot acquire the cache chain mutex then just give up - we'll try
4048 * again on the next iteration.
4050 static void cache_reap(struct work_struct *w)
4052 struct kmem_cache *searchp;
4053 struct kmem_cache_node *n;
4054 int node = numa_mem_id();
4055 struct delayed_work *work = to_delayed_work(w);
4057 if (!mutex_trylock(&slab_mutex))
4058 /* Give up. Setup the next iteration. */
4061 list_for_each_entry(searchp, &slab_caches, list) {
4065 * We only take the node lock if absolutely necessary and we
4066 * have established with reasonable certainty that
4067 * we can do some work if the lock was obtained.
4069 n = get_node(searchp, node);
4071 reap_alien(searchp, n);
4073 drain_array(searchp, n, cpu_cache_get(searchp), node);
4076 * These are racy checks but it does not matter
4077 * if we skip one check or scan twice.
4079 if (time_after(n->next_reap, jiffies))
4082 n->next_reap = jiffies + REAPTIMEOUT_NODE;
4084 drain_array(searchp, n, n->shared, node);
4086 if (n->free_touched)
4087 n->free_touched = 0;
4091 freed = drain_freelist(searchp, n, (n->free_limit +
4092 5 * searchp->num - 1) / (5 * searchp->num));
4093 STATS_ADD_REAPED(searchp, freed);
4099 mutex_unlock(&slab_mutex);
4102 /* Set up the next iteration */
4103 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC));
4106 #ifdef CONFIG_SLABINFO
4107 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
4110 unsigned long active_objs;
4111 unsigned long num_objs;
4112 unsigned long active_slabs = 0;
4113 unsigned long num_slabs, free_objects = 0, shared_avail = 0;
4117 struct kmem_cache_node *n;
4121 for_each_kmem_cache_node(cachep, node, n) {
4124 spin_lock_irq(&n->list_lock);
4126 list_for_each_entry(page, &n->slabs_full, lru) {
4127 if (page->active != cachep->num && !error)
4128 error = "slabs_full accounting error";
4129 active_objs += cachep->num;
4132 list_for_each_entry(page, &n->slabs_partial, lru) {
4133 if (page->active == cachep->num && !error)
4134 error = "slabs_partial accounting error";
4135 if (!page->active && !error)
4136 error = "slabs_partial accounting error";
4137 active_objs += page->active;
4140 list_for_each_entry(page, &n->slabs_free, lru) {
4141 if (page->active && !error)
4142 error = "slabs_free accounting error";
4145 free_objects += n->free_objects;
4147 shared_avail += n->shared->avail;
4149 spin_unlock_irq(&n->list_lock);
4151 num_slabs += active_slabs;
4152 num_objs = num_slabs * cachep->num;
4153 if (num_objs - active_objs != free_objects && !error)
4154 error = "free_objects accounting error";
4156 name = cachep->name;
4158 pr_err("slab: cache %s error: %s\n", name, error);
4160 sinfo->active_objs = active_objs;
4161 sinfo->num_objs = num_objs;
4162 sinfo->active_slabs = active_slabs;
4163 sinfo->num_slabs = num_slabs;
4164 sinfo->shared_avail = shared_avail;
4165 sinfo->limit = cachep->limit;
4166 sinfo->batchcount = cachep->batchcount;
4167 sinfo->shared = cachep->shared;
4168 sinfo->objects_per_slab = cachep->num;
4169 sinfo->cache_order = cachep->gfporder;
4172 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
4176 unsigned long high = cachep->high_mark;
4177 unsigned long allocs = cachep->num_allocations;
4178 unsigned long grown = cachep->grown;
4179 unsigned long reaped = cachep->reaped;
4180 unsigned long errors = cachep->errors;
4181 unsigned long max_freeable = cachep->max_freeable;
4182 unsigned long node_allocs = cachep->node_allocs;
4183 unsigned long node_frees = cachep->node_frees;
4184 unsigned long overflows = cachep->node_overflow;
4186 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu",
4187 allocs, high, grown,
4188 reaped, errors, max_freeable, node_allocs,
4189 node_frees, overflows);
4193 unsigned long allochit = atomic_read(&cachep->allochit);
4194 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4195 unsigned long freehit = atomic_read(&cachep->freehit);
4196 unsigned long freemiss = atomic_read(&cachep->freemiss);
4198 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4199 allochit, allocmiss, freehit, freemiss);
4204 #define MAX_SLABINFO_WRITE 128
4206 * slabinfo_write - Tuning for the slab allocator
4208 * @buffer: user buffer
4209 * @count: data length
4212 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
4213 size_t count, loff_t *ppos)
4215 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4216 int limit, batchcount, shared, res;
4217 struct kmem_cache *cachep;
4219 if (count > MAX_SLABINFO_WRITE)
4221 if (copy_from_user(&kbuf, buffer, count))
4223 kbuf[MAX_SLABINFO_WRITE] = '\0';
4225 tmp = strchr(kbuf, ' ');
4230 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4233 /* Find the cache in the chain of caches. */
4234 mutex_lock(&slab_mutex);
4236 list_for_each_entry(cachep, &slab_caches, list) {
4237 if (!strcmp(cachep->name, kbuf)) {
4238 if (limit < 1 || batchcount < 1 ||
4239 batchcount > limit || shared < 0) {
4242 res = do_tune_cpucache(cachep, limit,
4249 mutex_unlock(&slab_mutex);
4255 #ifdef CONFIG_DEBUG_SLAB_LEAK
4257 static inline int add_caller(unsigned long *n, unsigned long v)
4267 unsigned long *q = p + 2 * i;
4281 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4287 static void handle_slab(unsigned long *n, struct kmem_cache *c,
4296 for (i = 0, p = page->s_mem; i < c->num; i++, p += c->size) {
4299 for (j = page->active; j < c->num; j++) {
4300 if (get_free_obj(page, j) == i) {
4310 * probe_kernel_read() is used for DEBUG_PAGEALLOC. page table
4311 * mapping is established when actual object allocation and
4312 * we could mistakenly access the unmapped object in the cpu
4315 if (probe_kernel_read(&v, dbg_userword(c, p), sizeof(v)))
4318 if (!add_caller(n, v))
4323 static void show_symbol(struct seq_file *m, unsigned long address)
4325 #ifdef CONFIG_KALLSYMS
4326 unsigned long offset, size;
4327 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4329 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4330 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4332 seq_printf(m, " [%s]", modname);
4336 seq_printf(m, "%p", (void *)address);
4339 static int leaks_show(struct seq_file *m, void *p)
4341 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
4343 struct kmem_cache_node *n;
4345 unsigned long *x = m->private;
4349 if (!(cachep->flags & SLAB_STORE_USER))
4351 if (!(cachep->flags & SLAB_RED_ZONE))
4355 * Set store_user_clean and start to grab stored user information
4356 * for all objects on this cache. If some alloc/free requests comes
4357 * during the processing, information would be wrong so restart
4361 set_store_user_clean(cachep);
4362 drain_cpu_caches(cachep);
4366 for_each_kmem_cache_node(cachep, node, n) {
4369 spin_lock_irq(&n->list_lock);
4371 list_for_each_entry(page, &n->slabs_full, lru)
4372 handle_slab(x, cachep, page);
4373 list_for_each_entry(page, &n->slabs_partial, lru)
4374 handle_slab(x, cachep, page);
4375 spin_unlock_irq(&n->list_lock);
4377 } while (!is_store_user_clean(cachep));
4379 name = cachep->name;
4381 /* Increase the buffer size */
4382 mutex_unlock(&slab_mutex);
4383 m->private = kzalloc(x[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4385 /* Too bad, we are really out */
4387 mutex_lock(&slab_mutex);
4390 *(unsigned long *)m->private = x[0] * 2;
4392 mutex_lock(&slab_mutex);
4393 /* Now make sure this entry will be retried */
4397 for (i = 0; i < x[1]; i++) {
4398 seq_printf(m, "%s: %lu ", name, x[2*i+3]);
4399 show_symbol(m, x[2*i+2]);
4406 static const struct seq_operations slabstats_op = {
4407 .start = slab_start,
4413 static int slabstats_open(struct inode *inode, struct file *file)
4417 n = __seq_open_private(file, &slabstats_op, PAGE_SIZE);
4421 *n = PAGE_SIZE / (2 * sizeof(unsigned long));
4426 static const struct file_operations proc_slabstats_operations = {
4427 .open = slabstats_open,
4429 .llseek = seq_lseek,
4430 .release = seq_release_private,
4434 static int __init slab_proc_init(void)
4436 #ifdef CONFIG_DEBUG_SLAB_LEAK
4437 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4441 module_init(slab_proc_init);
4444 #ifdef CONFIG_HARDENED_USERCOPY
4446 * Rejects objects that are incorrectly sized.
4448 * Returns NULL if check passes, otherwise const char * to name of cache
4449 * to indicate an error.
4451 const char *__check_heap_object(const void *ptr, unsigned long n,
4454 struct kmem_cache *cachep;
4456 unsigned long offset;
4458 /* Find and validate object. */
4459 cachep = page->slab_cache;
4460 objnr = obj_to_index(cachep, page, (void *)ptr);
4461 BUG_ON(objnr >= cachep->num);
4463 /* Find offset within object. */
4464 offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep);
4466 /* Allow address range falling entirely within object size. */
4467 if (offset <= cachep->object_size && n <= cachep->object_size - offset)
4470 return cachep->name;
4472 #endif /* CONFIG_HARDENED_USERCOPY */
4475 * ksize - get the actual amount of memory allocated for a given object
4476 * @objp: Pointer to the object
4478 * kmalloc may internally round up allocations and return more memory
4479 * than requested. ksize() can be used to determine the actual amount of
4480 * memory allocated. The caller may use this additional memory, even though
4481 * a smaller amount of memory was initially specified with the kmalloc call.
4482 * The caller must guarantee that objp points to a valid object previously
4483 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4484 * must not be freed during the duration of the call.
4486 size_t ksize(const void *objp)
4491 if (unlikely(objp == ZERO_SIZE_PTR))
4494 size = virt_to_cache(objp)->object_size;
4495 /* We assume that ksize callers could use the whole allocated area,
4496 * so we need to unpoison this area.
4498 kasan_unpoison_shadow(objp, size);
4502 EXPORT_SYMBOL(ksize);