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
161 * true if a page was allocated from pfmemalloc reserves for network-based
164 static bool pfmemalloc_active __read_mostly;
170 * - LIFO ordering, to hand out cache-warm objects from _alloc
171 * - reduce the number of linked list operations
172 * - reduce spinlock operations
174 * The limit is stored in the per-cpu structure to reduce the data cache
181 unsigned int batchcount;
182 unsigned int touched;
185 * Must have this definition in here for the proper
186 * alignment of array_cache. Also simplifies accessing
189 * Entries should not be directly dereferenced as
190 * entries belonging to slabs marked pfmemalloc will
191 * have the lower bits set SLAB_OBJ_PFMEMALLOC
195 #define SLAB_OBJ_PFMEMALLOC 1
196 static inline bool is_obj_pfmemalloc(void *objp)
198 return (unsigned long)objp & SLAB_OBJ_PFMEMALLOC;
201 static inline void set_obj_pfmemalloc(void **objp)
203 *objp = (void *)((unsigned long)*objp | SLAB_OBJ_PFMEMALLOC);
207 static inline void clear_obj_pfmemalloc(void **objp)
209 *objp = (void *)((unsigned long)*objp & ~SLAB_OBJ_PFMEMALLOC);
213 * bootstrap: The caches do not work without cpuarrays anymore, but the
214 * cpuarrays are allocated from the generic caches...
216 #define BOOT_CPUCACHE_ENTRIES 1
217 struct arraycache_init {
218 struct array_cache cache;
219 void *entries[BOOT_CPUCACHE_ENTRIES];
223 * Need this for bootstrapping a per node allocator.
225 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
226 static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS];
227 #define CACHE_CACHE 0
228 #define SIZE_AC MAX_NUMNODES
229 #define SIZE_NODE (2 * MAX_NUMNODES)
231 static int drain_freelist(struct kmem_cache *cache,
232 struct kmem_cache_node *n, int tofree);
233 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
235 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
236 static void cache_reap(struct work_struct *unused);
238 static int slab_early_init = 1;
240 #define INDEX_AC kmalloc_index(sizeof(struct arraycache_init))
241 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
243 static void kmem_cache_node_init(struct kmem_cache_node *parent)
245 INIT_LIST_HEAD(&parent->slabs_full);
246 INIT_LIST_HEAD(&parent->slabs_partial);
247 INIT_LIST_HEAD(&parent->slabs_free);
248 parent->shared = NULL;
249 parent->alien = NULL;
250 parent->colour_next = 0;
251 spin_lock_init(&parent->list_lock);
252 parent->free_objects = 0;
253 parent->free_touched = 0;
256 #define MAKE_LIST(cachep, listp, slab, nodeid) \
258 INIT_LIST_HEAD(listp); \
259 list_splice(&(cachep->node[nodeid]->slab), listp); \
262 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
264 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
265 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
266 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
269 #define CFLGS_OFF_SLAB (0x80000000UL)
270 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
272 #define BATCHREFILL_LIMIT 16
274 * Optimization question: fewer reaps means less probability for unnessary
275 * cpucache drain/refill cycles.
277 * OTOH the cpuarrays can contain lots of objects,
278 * which could lock up otherwise freeable slabs.
280 #define REAPTIMEOUT_CPUC (2*HZ)
281 #define REAPTIMEOUT_LIST3 (4*HZ)
284 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
285 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
286 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
287 #define STATS_INC_GROWN(x) ((x)->grown++)
288 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
289 #define STATS_SET_HIGH(x) \
291 if ((x)->num_active > (x)->high_mark) \
292 (x)->high_mark = (x)->num_active; \
294 #define STATS_INC_ERR(x) ((x)->errors++)
295 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
296 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
297 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
298 #define STATS_SET_FREEABLE(x, i) \
300 if ((x)->max_freeable < i) \
301 (x)->max_freeable = i; \
303 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
304 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
305 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
306 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
308 #define STATS_INC_ACTIVE(x) do { } while (0)
309 #define STATS_DEC_ACTIVE(x) do { } while (0)
310 #define STATS_INC_ALLOCED(x) do { } while (0)
311 #define STATS_INC_GROWN(x) do { } while (0)
312 #define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0)
313 #define STATS_SET_HIGH(x) do { } while (0)
314 #define STATS_INC_ERR(x) do { } while (0)
315 #define STATS_INC_NODEALLOCS(x) do { } while (0)
316 #define STATS_INC_NODEFREES(x) do { } while (0)
317 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
318 #define STATS_SET_FREEABLE(x, i) do { } while (0)
319 #define STATS_INC_ALLOCHIT(x) do { } while (0)
320 #define STATS_INC_ALLOCMISS(x) do { } while (0)
321 #define STATS_INC_FREEHIT(x) do { } while (0)
322 #define STATS_INC_FREEMISS(x) do { } while (0)
328 * memory layout of objects:
330 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
331 * the end of an object is aligned with the end of the real
332 * allocation. Catches writes behind the end of the allocation.
333 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
335 * cachep->obj_offset: The real object.
336 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
337 * cachep->size - 1* BYTES_PER_WORD: last caller address
338 * [BYTES_PER_WORD long]
340 static int obj_offset(struct kmem_cache *cachep)
342 return cachep->obj_offset;
345 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
347 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
348 return (unsigned long long*) (objp + obj_offset(cachep) -
349 sizeof(unsigned long long));
352 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
354 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
355 if (cachep->flags & SLAB_STORE_USER)
356 return (unsigned long long *)(objp + cachep->size -
357 sizeof(unsigned long long) -
359 return (unsigned long long *) (objp + cachep->size -
360 sizeof(unsigned long long));
363 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
365 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
366 return (void **)(objp + cachep->size - BYTES_PER_WORD);
371 #define obj_offset(x) 0
372 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
373 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
374 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
378 #define OBJECT_FREE (0)
379 #define OBJECT_ACTIVE (1)
381 #ifdef CONFIG_DEBUG_SLAB_LEAK
383 static void set_obj_status(struct page *page, int idx, int val)
387 struct kmem_cache *cachep = page->slab_cache;
389 freelist_size = cachep->num * sizeof(unsigned int);
390 status = (char *)page->freelist + freelist_size;
394 static inline unsigned int get_obj_status(struct page *page, int idx)
398 struct kmem_cache *cachep = page->slab_cache;
400 freelist_size = cachep->num * sizeof(unsigned int);
401 status = (char *)page->freelist + freelist_size;
407 static inline void set_obj_status(struct page *page, int idx, int val) {}
412 * Do not go above this order unless 0 objects fit into the slab or
413 * overridden on the command line.
415 #define SLAB_MAX_ORDER_HI 1
416 #define SLAB_MAX_ORDER_LO 0
417 static int slab_max_order = SLAB_MAX_ORDER_LO;
418 static bool slab_max_order_set __initdata;
420 static inline struct kmem_cache *virt_to_cache(const void *obj)
422 struct page *page = virt_to_head_page(obj);
423 return page->slab_cache;
426 static inline void *index_to_obj(struct kmem_cache *cache, struct page *page,
429 return page->s_mem + cache->size * idx;
433 * We want to avoid an expensive divide : (offset / cache->size)
434 * Using the fact that size is a constant for a particular cache,
435 * we can replace (offset / cache->size) by
436 * reciprocal_divide(offset, cache->reciprocal_buffer_size)
438 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
439 const struct page *page, void *obj)
441 u32 offset = (obj - page->s_mem);
442 return reciprocal_divide(offset, cache->reciprocal_buffer_size);
445 static struct arraycache_init initarray_generic =
446 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
448 /* internal cache of cache description objs */
449 static struct kmem_cache kmem_cache_boot = {
451 .limit = BOOT_CPUCACHE_ENTRIES,
453 .size = sizeof(struct kmem_cache),
454 .name = "kmem_cache",
457 #define BAD_ALIEN_MAGIC 0x01020304ul
459 #ifdef CONFIG_LOCKDEP
462 * Slab sometimes uses the kmalloc slabs to store the slab headers
463 * for other slabs "off slab".
464 * The locking for this is tricky in that it nests within the locks
465 * of all other slabs in a few places; to deal with this special
466 * locking we put on-slab caches into a separate lock-class.
468 * We set lock class for alien array caches which are up during init.
469 * The lock annotation will be lost if all cpus of a node goes down and
470 * then comes back up during hotplug
472 static struct lock_class_key on_slab_l3_key;
473 static struct lock_class_key on_slab_alc_key;
475 static struct lock_class_key debugobj_l3_key;
476 static struct lock_class_key debugobj_alc_key;
478 static void slab_set_lock_classes(struct kmem_cache *cachep,
479 struct lock_class_key *l3_key, struct lock_class_key *alc_key,
482 struct array_cache **alc;
483 struct kmem_cache_node *n;
490 lockdep_set_class(&n->list_lock, l3_key);
493 * FIXME: This check for BAD_ALIEN_MAGIC
494 * should go away when common slab code is taught to
495 * work even without alien caches.
496 * Currently, non NUMA code returns BAD_ALIEN_MAGIC
497 * for alloc_alien_cache,
499 if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
503 lockdep_set_class(&alc[r]->lock, alc_key);
507 static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
509 slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node);
512 static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
516 for_each_online_node(node)
517 slab_set_debugobj_lock_classes_node(cachep, node);
520 static void init_node_lock_keys(int q)
527 for (i = 1; i <= KMALLOC_SHIFT_HIGH; i++) {
528 struct kmem_cache_node *n;
529 struct kmem_cache *cache = kmalloc_caches[i];
535 if (!n || OFF_SLAB(cache))
538 slab_set_lock_classes(cache, &on_slab_l3_key,
539 &on_slab_alc_key, q);
543 static void on_slab_lock_classes_node(struct kmem_cache *cachep, int q)
545 if (!cachep->node[q])
548 slab_set_lock_classes(cachep, &on_slab_l3_key,
549 &on_slab_alc_key, q);
552 static inline void on_slab_lock_classes(struct kmem_cache *cachep)
556 VM_BUG_ON(OFF_SLAB(cachep));
558 on_slab_lock_classes_node(cachep, node);
561 static inline void init_lock_keys(void)
566 init_node_lock_keys(node);
569 static void init_node_lock_keys(int q)
573 static inline void init_lock_keys(void)
577 static inline void on_slab_lock_classes(struct kmem_cache *cachep)
581 static inline void on_slab_lock_classes_node(struct kmem_cache *cachep, int node)
585 static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
589 static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
594 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
596 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
598 return cachep->array[smp_processor_id()];
601 static size_t calculate_freelist_size(int nr_objs, size_t align)
603 size_t freelist_size;
605 freelist_size = nr_objs * sizeof(unsigned int);
606 if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
607 freelist_size += nr_objs * sizeof(char);
610 freelist_size = ALIGN(freelist_size, align);
612 return freelist_size;
616 * Calculate the number of objects and left-over bytes for a given buffer size.
618 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
619 size_t align, int flags, size_t *left_over,
624 size_t slab_size = PAGE_SIZE << gfporder;
627 * The slab management structure can be either off the slab or
628 * on it. For the latter case, the memory allocated for a
631 * - One unsigned int for each object
632 * - Padding to respect alignment of @align
633 * - @buffer_size bytes for each object
635 * If the slab management structure is off the slab, then the
636 * alignment will already be calculated into the size. Because
637 * the slabs are all pages aligned, the objects will be at the
638 * correct alignment when allocated.
640 if (flags & CFLGS_OFF_SLAB) {
642 nr_objs = slab_size / buffer_size;
647 if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
648 extra_space = sizeof(char);
650 * Ignore padding for the initial guess. The padding
651 * is at most @align-1 bytes, and @buffer_size is at
652 * least @align. In the worst case, this result will
653 * be one greater than the number of objects that fit
654 * into the memory allocation when taking the padding
657 nr_objs = (slab_size) /
658 (buffer_size + sizeof(unsigned int) + extra_space);
661 * This calculated number will be either the right
662 * amount, or one greater than what we want.
664 if (calculate_freelist_size(nr_objs, align) >
665 slab_size - nr_objs * buffer_size)
668 mgmt_size = calculate_freelist_size(nr_objs, align);
671 *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
675 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
677 static void __slab_error(const char *function, struct kmem_cache *cachep,
680 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
681 function, cachep->name, msg);
683 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
688 * By default on NUMA we use alien caches to stage the freeing of
689 * objects allocated from other nodes. This causes massive memory
690 * inefficiencies when using fake NUMA setup to split memory into a
691 * large number of small nodes, so it can be disabled on the command
695 static int use_alien_caches __read_mostly = 1;
696 static int __init noaliencache_setup(char *s)
698 use_alien_caches = 0;
701 __setup("noaliencache", noaliencache_setup);
703 static int __init slab_max_order_setup(char *str)
705 get_option(&str, &slab_max_order);
706 slab_max_order = slab_max_order < 0 ? 0 :
707 min(slab_max_order, MAX_ORDER - 1);
708 slab_max_order_set = true;
712 __setup("slab_max_order=", slab_max_order_setup);
716 * Special reaping functions for NUMA systems called from cache_reap().
717 * These take care of doing round robin flushing of alien caches (containing
718 * objects freed on different nodes from which they were allocated) and the
719 * flushing of remote pcps by calling drain_node_pages.
721 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
723 static void init_reap_node(int cpu)
727 node = next_node(cpu_to_mem(cpu), node_online_map);
728 if (node == MAX_NUMNODES)
729 node = first_node(node_online_map);
731 per_cpu(slab_reap_node, cpu) = node;
734 static void next_reap_node(void)
736 int node = __this_cpu_read(slab_reap_node);
738 node = next_node(node, node_online_map);
739 if (unlikely(node >= MAX_NUMNODES))
740 node = first_node(node_online_map);
741 __this_cpu_write(slab_reap_node, node);
745 #define init_reap_node(cpu) do { } while (0)
746 #define next_reap_node(void) do { } while (0)
750 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
751 * via the workqueue/eventd.
752 * Add the CPU number into the expiration time to minimize the possibility of
753 * the CPUs getting into lockstep and contending for the global cache chain
756 static void start_cpu_timer(int cpu)
758 struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
761 * When this gets called from do_initcalls via cpucache_init(),
762 * init_workqueues() has already run, so keventd will be setup
765 if (keventd_up() && reap_work->work.func == NULL) {
767 INIT_DEFERRABLE_WORK(reap_work, cache_reap);
768 schedule_delayed_work_on(cpu, reap_work,
769 __round_jiffies_relative(HZ, cpu));
773 static struct array_cache *alloc_arraycache(int node, int entries,
774 int batchcount, gfp_t gfp)
776 int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
777 struct array_cache *nc = NULL;
779 nc = kmalloc_node(memsize, gfp, node);
781 * The array_cache structures contain pointers to free object.
782 * However, when such objects are allocated or transferred to another
783 * cache the pointers are not cleared and they could be counted as
784 * valid references during a kmemleak scan. Therefore, kmemleak must
785 * not scan such objects.
787 kmemleak_no_scan(nc);
791 nc->batchcount = batchcount;
793 spin_lock_init(&nc->lock);
798 static inline bool is_slab_pfmemalloc(struct page *page)
800 return PageSlabPfmemalloc(page);
803 /* Clears pfmemalloc_active if no slabs have pfmalloc set */
804 static void recheck_pfmemalloc_active(struct kmem_cache *cachep,
805 struct array_cache *ac)
807 struct kmem_cache_node *n = cachep->node[numa_mem_id()];
811 if (!pfmemalloc_active)
814 spin_lock_irqsave(&n->list_lock, flags);
815 list_for_each_entry(page, &n->slabs_full, lru)
816 if (is_slab_pfmemalloc(page))
819 list_for_each_entry(page, &n->slabs_partial, lru)
820 if (is_slab_pfmemalloc(page))
823 list_for_each_entry(page, &n->slabs_free, lru)
824 if (is_slab_pfmemalloc(page))
827 pfmemalloc_active = false;
829 spin_unlock_irqrestore(&n->list_lock, flags);
832 static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
833 gfp_t flags, bool force_refill)
836 void *objp = ac->entry[--ac->avail];
838 /* Ensure the caller is allowed to use objects from PFMEMALLOC slab */
839 if (unlikely(is_obj_pfmemalloc(objp))) {
840 struct kmem_cache_node *n;
842 if (gfp_pfmemalloc_allowed(flags)) {
843 clear_obj_pfmemalloc(&objp);
847 /* The caller cannot use PFMEMALLOC objects, find another one */
848 for (i = 0; i < ac->avail; i++) {
849 /* If a !PFMEMALLOC object is found, swap them */
850 if (!is_obj_pfmemalloc(ac->entry[i])) {
852 ac->entry[i] = ac->entry[ac->avail];
853 ac->entry[ac->avail] = objp;
859 * If there are empty slabs on the slabs_free list and we are
860 * being forced to refill the cache, mark this one !pfmemalloc.
862 n = cachep->node[numa_mem_id()];
863 if (!list_empty(&n->slabs_free) && force_refill) {
864 struct page *page = virt_to_head_page(objp);
865 ClearPageSlabPfmemalloc(page);
866 clear_obj_pfmemalloc(&objp);
867 recheck_pfmemalloc_active(cachep, ac);
871 /* No !PFMEMALLOC objects available */
879 static inline void *ac_get_obj(struct kmem_cache *cachep,
880 struct array_cache *ac, gfp_t flags, bool force_refill)
884 if (unlikely(sk_memalloc_socks()))
885 objp = __ac_get_obj(cachep, ac, flags, force_refill);
887 objp = ac->entry[--ac->avail];
892 static void *__ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
895 if (unlikely(pfmemalloc_active)) {
896 /* Some pfmemalloc slabs exist, check if this is one */
897 struct page *page = virt_to_head_page(objp);
898 if (PageSlabPfmemalloc(page))
899 set_obj_pfmemalloc(&objp);
905 static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
908 if (unlikely(sk_memalloc_socks()))
909 objp = __ac_put_obj(cachep, ac, objp);
911 ac->entry[ac->avail++] = objp;
915 * Transfer objects in one arraycache to another.
916 * Locking must be handled by the caller.
918 * Return the number of entries transferred.
920 static int transfer_objects(struct array_cache *to,
921 struct array_cache *from, unsigned int max)
923 /* Figure out how many entries to transfer */
924 int nr = min3(from->avail, max, to->limit - to->avail);
929 memcpy(to->entry + to->avail, from->entry + from->avail -nr,
939 #define drain_alien_cache(cachep, alien) do { } while (0)
940 #define reap_alien(cachep, n) do { } while (0)
942 static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
944 return (struct array_cache **)BAD_ALIEN_MAGIC;
947 static inline void free_alien_cache(struct array_cache **ac_ptr)
951 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
956 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
962 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
963 gfp_t flags, int nodeid)
968 #else /* CONFIG_NUMA */
970 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
971 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
973 static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
975 struct array_cache **ac_ptr;
976 int memsize = sizeof(void *) * nr_node_ids;
981 ac_ptr = kzalloc_node(memsize, gfp, node);
984 if (i == node || !node_online(i))
986 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
988 for (i--; i >= 0; i--)
998 static void free_alien_cache(struct array_cache **ac_ptr)
1009 static void __drain_alien_cache(struct kmem_cache *cachep,
1010 struct array_cache *ac, int node)
1012 struct kmem_cache_node *n = cachep->node[node];
1015 spin_lock(&n->list_lock);
1017 * Stuff objects into the remote nodes shared array first.
1018 * That way we could avoid the overhead of putting the objects
1019 * into the free lists and getting them back later.
1022 transfer_objects(n->shared, ac, ac->limit);
1024 free_block(cachep, ac->entry, ac->avail, node);
1026 spin_unlock(&n->list_lock);
1031 * Called from cache_reap() to regularly drain alien caches round robin.
1033 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
1035 int node = __this_cpu_read(slab_reap_node);
1038 struct array_cache *ac = n->alien[node];
1040 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1041 __drain_alien_cache(cachep, ac, node);
1042 spin_unlock_irq(&ac->lock);
1047 static void drain_alien_cache(struct kmem_cache *cachep,
1048 struct array_cache **alien)
1051 struct array_cache *ac;
1052 unsigned long flags;
1054 for_each_online_node(i) {
1057 spin_lock_irqsave(&ac->lock, flags);
1058 __drain_alien_cache(cachep, ac, i);
1059 spin_unlock_irqrestore(&ac->lock, flags);
1064 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1066 int nodeid = page_to_nid(virt_to_page(objp));
1067 struct kmem_cache_node *n;
1068 struct array_cache *alien = NULL;
1071 node = numa_mem_id();
1074 * Make sure we are not freeing a object from another node to the array
1075 * cache on this cpu.
1077 if (likely(nodeid == node))
1080 n = cachep->node[node];
1081 STATS_INC_NODEFREES(cachep);
1082 if (n->alien && n->alien[nodeid]) {
1083 alien = n->alien[nodeid];
1084 spin_lock(&alien->lock);
1085 if (unlikely(alien->avail == alien->limit)) {
1086 STATS_INC_ACOVERFLOW(cachep);
1087 __drain_alien_cache(cachep, alien, nodeid);
1089 ac_put_obj(cachep, alien, objp);
1090 spin_unlock(&alien->lock);
1092 spin_lock(&(cachep->node[nodeid])->list_lock);
1093 free_block(cachep, &objp, 1, nodeid);
1094 spin_unlock(&(cachep->node[nodeid])->list_lock);
1101 * Allocates and initializes node for a node on each slab cache, used for
1102 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node
1103 * will be allocated off-node since memory is not yet online for the new node.
1104 * When hotplugging memory or a cpu, existing node are not replaced if
1107 * Must hold slab_mutex.
1109 static int init_cache_node_node(int node)
1111 struct kmem_cache *cachep;
1112 struct kmem_cache_node *n;
1113 const int memsize = sizeof(struct kmem_cache_node);
1115 list_for_each_entry(cachep, &slab_caches, list) {
1117 * Set up the size64 kmemlist for cpu before we can
1118 * begin anything. Make sure some other cpu on this
1119 * node has not already allocated this
1121 if (!cachep->node[node]) {
1122 n = kmalloc_node(memsize, GFP_KERNEL, node);
1125 kmem_cache_node_init(n);
1126 n->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1127 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1130 * The l3s don't come and go as CPUs come and
1131 * go. slab_mutex is sufficient
1134 cachep->node[node] = n;
1137 spin_lock_irq(&cachep->node[node]->list_lock);
1138 cachep->node[node]->free_limit =
1139 (1 + nr_cpus_node(node)) *
1140 cachep->batchcount + cachep->num;
1141 spin_unlock_irq(&cachep->node[node]->list_lock);
1146 static inline int slabs_tofree(struct kmem_cache *cachep,
1147 struct kmem_cache_node *n)
1149 return (n->free_objects + cachep->num - 1) / cachep->num;
1152 static void cpuup_canceled(long cpu)
1154 struct kmem_cache *cachep;
1155 struct kmem_cache_node *n = NULL;
1156 int node = cpu_to_mem(cpu);
1157 const struct cpumask *mask = cpumask_of_node(node);
1159 list_for_each_entry(cachep, &slab_caches, list) {
1160 struct array_cache *nc;
1161 struct array_cache *shared;
1162 struct array_cache **alien;
1164 /* cpu is dead; no one can alloc from it. */
1165 nc = cachep->array[cpu];
1166 cachep->array[cpu] = NULL;
1167 n = cachep->node[node];
1170 goto free_array_cache;
1172 spin_lock_irq(&n->list_lock);
1174 /* Free limit for this kmem_cache_node */
1175 n->free_limit -= cachep->batchcount;
1177 free_block(cachep, nc->entry, nc->avail, node);
1179 if (!cpumask_empty(mask)) {
1180 spin_unlock_irq(&n->list_lock);
1181 goto free_array_cache;
1186 free_block(cachep, shared->entry,
1187 shared->avail, node);
1194 spin_unlock_irq(&n->list_lock);
1198 drain_alien_cache(cachep, alien);
1199 free_alien_cache(alien);
1205 * In the previous loop, all the objects were freed to
1206 * the respective cache's slabs, now we can go ahead and
1207 * shrink each nodelist to its limit.
1209 list_for_each_entry(cachep, &slab_caches, list) {
1210 n = cachep->node[node];
1213 drain_freelist(cachep, n, slabs_tofree(cachep, n));
1217 static int cpuup_prepare(long cpu)
1219 struct kmem_cache *cachep;
1220 struct kmem_cache_node *n = NULL;
1221 int node = cpu_to_mem(cpu);
1225 * We need to do this right in the beginning since
1226 * alloc_arraycache's are going to use this list.
1227 * kmalloc_node allows us to add the slab to the right
1228 * kmem_cache_node and not this cpu's kmem_cache_node
1230 err = init_cache_node_node(node);
1235 * Now we can go ahead with allocating the shared arrays and
1238 list_for_each_entry(cachep, &slab_caches, list) {
1239 struct array_cache *nc;
1240 struct array_cache *shared = NULL;
1241 struct array_cache **alien = NULL;
1243 nc = alloc_arraycache(node, cachep->limit,
1244 cachep->batchcount, GFP_KERNEL);
1247 if (cachep->shared) {
1248 shared = alloc_arraycache(node,
1249 cachep->shared * cachep->batchcount,
1250 0xbaadf00d, GFP_KERNEL);
1256 if (use_alien_caches) {
1257 alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
1264 cachep->array[cpu] = nc;
1265 n = cachep->node[node];
1268 spin_lock_irq(&n->list_lock);
1271 * We are serialised from CPU_DEAD or
1272 * CPU_UP_CANCELLED by the cpucontrol lock
1283 spin_unlock_irq(&n->list_lock);
1285 free_alien_cache(alien);
1286 if (cachep->flags & SLAB_DEBUG_OBJECTS)
1287 slab_set_debugobj_lock_classes_node(cachep, node);
1288 else if (!OFF_SLAB(cachep) &&
1289 !(cachep->flags & SLAB_DESTROY_BY_RCU))
1290 on_slab_lock_classes_node(cachep, node);
1292 init_node_lock_keys(node);
1296 cpuup_canceled(cpu);
1300 static int cpuup_callback(struct notifier_block *nfb,
1301 unsigned long action, void *hcpu)
1303 long cpu = (long)hcpu;
1307 case CPU_UP_PREPARE:
1308 case CPU_UP_PREPARE_FROZEN:
1309 mutex_lock(&slab_mutex);
1310 err = cpuup_prepare(cpu);
1311 mutex_unlock(&slab_mutex);
1314 case CPU_ONLINE_FROZEN:
1315 start_cpu_timer(cpu);
1317 #ifdef CONFIG_HOTPLUG_CPU
1318 case CPU_DOWN_PREPARE:
1319 case CPU_DOWN_PREPARE_FROZEN:
1321 * Shutdown cache reaper. Note that the slab_mutex is
1322 * held so that if cache_reap() is invoked it cannot do
1323 * anything expensive but will only modify reap_work
1324 * and reschedule the timer.
1326 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
1327 /* Now the cache_reaper is guaranteed to be not running. */
1328 per_cpu(slab_reap_work, cpu).work.func = NULL;
1330 case CPU_DOWN_FAILED:
1331 case CPU_DOWN_FAILED_FROZEN:
1332 start_cpu_timer(cpu);
1335 case CPU_DEAD_FROZEN:
1337 * Even if all the cpus of a node are down, we don't free the
1338 * kmem_cache_node of any cache. This to avoid a race between
1339 * cpu_down, and a kmalloc allocation from another cpu for
1340 * memory from the node of the cpu going down. The node
1341 * structure is usually allocated from kmem_cache_create() and
1342 * gets destroyed at kmem_cache_destroy().
1346 case CPU_UP_CANCELED:
1347 case CPU_UP_CANCELED_FROZEN:
1348 mutex_lock(&slab_mutex);
1349 cpuup_canceled(cpu);
1350 mutex_unlock(&slab_mutex);
1353 return notifier_from_errno(err);
1356 static struct notifier_block cpucache_notifier = {
1357 &cpuup_callback, NULL, 0
1360 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1362 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1363 * Returns -EBUSY if all objects cannot be drained so that the node is not
1366 * Must hold slab_mutex.
1368 static int __meminit drain_cache_node_node(int node)
1370 struct kmem_cache *cachep;
1373 list_for_each_entry(cachep, &slab_caches, list) {
1374 struct kmem_cache_node *n;
1376 n = cachep->node[node];
1380 drain_freelist(cachep, n, slabs_tofree(cachep, n));
1382 if (!list_empty(&n->slabs_full) ||
1383 !list_empty(&n->slabs_partial)) {
1391 static int __meminit slab_memory_callback(struct notifier_block *self,
1392 unsigned long action, void *arg)
1394 struct memory_notify *mnb = arg;
1398 nid = mnb->status_change_nid;
1403 case MEM_GOING_ONLINE:
1404 mutex_lock(&slab_mutex);
1405 ret = init_cache_node_node(nid);
1406 mutex_unlock(&slab_mutex);
1408 case MEM_GOING_OFFLINE:
1409 mutex_lock(&slab_mutex);
1410 ret = drain_cache_node_node(nid);
1411 mutex_unlock(&slab_mutex);
1415 case MEM_CANCEL_ONLINE:
1416 case MEM_CANCEL_OFFLINE:
1420 return notifier_from_errno(ret);
1422 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1425 * swap the static kmem_cache_node with kmalloced memory
1427 static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list,
1430 struct kmem_cache_node *ptr;
1432 ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid);
1435 memcpy(ptr, list, sizeof(struct kmem_cache_node));
1437 * Do not assume that spinlocks can be initialized via memcpy:
1439 spin_lock_init(&ptr->list_lock);
1441 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1442 cachep->node[nodeid] = ptr;
1446 * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1447 * size of kmem_cache_node.
1449 static void __init set_up_node(struct kmem_cache *cachep, int index)
1453 for_each_online_node(node) {
1454 cachep->node[node] = &init_kmem_cache_node[index + node];
1455 cachep->node[node]->next_reap = jiffies +
1457 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1462 * The memory after the last cpu cache pointer is used for the
1465 static void setup_node_pointer(struct kmem_cache *cachep)
1467 cachep->node = (struct kmem_cache_node **)&cachep->array[nr_cpu_ids];
1471 * Initialisation. Called after the page allocator have been initialised and
1472 * before smp_init().
1474 void __init kmem_cache_init(void)
1478 BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) <
1479 sizeof(struct rcu_head));
1480 kmem_cache = &kmem_cache_boot;
1481 setup_node_pointer(kmem_cache);
1483 if (num_possible_nodes() == 1)
1484 use_alien_caches = 0;
1486 for (i = 0; i < NUM_INIT_LISTS; i++)
1487 kmem_cache_node_init(&init_kmem_cache_node[i]);
1489 set_up_node(kmem_cache, CACHE_CACHE);
1492 * Fragmentation resistance on low memory - only use bigger
1493 * page orders on machines with more than 32MB of memory if
1494 * not overridden on the command line.
1496 if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
1497 slab_max_order = SLAB_MAX_ORDER_HI;
1499 /* Bootstrap is tricky, because several objects are allocated
1500 * from caches that do not exist yet:
1501 * 1) initialize the kmem_cache cache: it contains the struct
1502 * kmem_cache structures of all caches, except kmem_cache itself:
1503 * kmem_cache is statically allocated.
1504 * Initially an __init data area is used for the head array and the
1505 * kmem_cache_node structures, it's replaced with a kmalloc allocated
1506 * array at the end of the bootstrap.
1507 * 2) Create the first kmalloc cache.
1508 * The struct kmem_cache for the new cache is allocated normally.
1509 * An __init data area is used for the head array.
1510 * 3) Create the remaining kmalloc caches, with minimally sized
1512 * 4) Replace the __init data head arrays for kmem_cache and the first
1513 * kmalloc cache with kmalloc allocated arrays.
1514 * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1515 * the other cache's with kmalloc allocated memory.
1516 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1519 /* 1) create the kmem_cache */
1522 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1524 create_boot_cache(kmem_cache, "kmem_cache",
1525 offsetof(struct kmem_cache, array[nr_cpu_ids]) +
1526 nr_node_ids * sizeof(struct kmem_cache_node *),
1527 SLAB_HWCACHE_ALIGN);
1528 list_add(&kmem_cache->list, &slab_caches);
1530 /* 2+3) create the kmalloc caches */
1533 * Initialize the caches that provide memory for the array cache and the
1534 * kmem_cache_node structures first. Without this, further allocations will
1538 kmalloc_caches[INDEX_AC] = create_kmalloc_cache("kmalloc-ac",
1539 kmalloc_size(INDEX_AC), ARCH_KMALLOC_FLAGS);
1541 if (INDEX_AC != INDEX_NODE)
1542 kmalloc_caches[INDEX_NODE] =
1543 create_kmalloc_cache("kmalloc-node",
1544 kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS);
1546 slab_early_init = 0;
1548 /* 4) Replace the bootstrap head arrays */
1550 struct array_cache *ptr;
1552 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1554 memcpy(ptr, cpu_cache_get(kmem_cache),
1555 sizeof(struct arraycache_init));
1557 * Do not assume that spinlocks can be initialized via memcpy:
1559 spin_lock_init(&ptr->lock);
1561 kmem_cache->array[smp_processor_id()] = ptr;
1563 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1565 BUG_ON(cpu_cache_get(kmalloc_caches[INDEX_AC])
1566 != &initarray_generic.cache);
1567 memcpy(ptr, cpu_cache_get(kmalloc_caches[INDEX_AC]),
1568 sizeof(struct arraycache_init));
1570 * Do not assume that spinlocks can be initialized via memcpy:
1572 spin_lock_init(&ptr->lock);
1574 kmalloc_caches[INDEX_AC]->array[smp_processor_id()] = ptr;
1576 /* 5) Replace the bootstrap kmem_cache_node */
1580 for_each_online_node(nid) {
1581 init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid);
1583 init_list(kmalloc_caches[INDEX_AC],
1584 &init_kmem_cache_node[SIZE_AC + nid], nid);
1586 if (INDEX_AC != INDEX_NODE) {
1587 init_list(kmalloc_caches[INDEX_NODE],
1588 &init_kmem_cache_node[SIZE_NODE + nid], nid);
1593 create_kmalloc_caches(ARCH_KMALLOC_FLAGS);
1596 void __init kmem_cache_init_late(void)
1598 struct kmem_cache *cachep;
1602 /* 6) resize the head arrays to their final sizes */
1603 mutex_lock(&slab_mutex);
1604 list_for_each_entry(cachep, &slab_caches, list)
1605 if (enable_cpucache(cachep, GFP_NOWAIT))
1607 mutex_unlock(&slab_mutex);
1609 /* Annotate slab for lockdep -- annotate the malloc caches */
1616 * Register a cpu startup notifier callback that initializes
1617 * cpu_cache_get for all new cpus
1619 register_cpu_notifier(&cpucache_notifier);
1623 * Register a memory hotplug callback that initializes and frees
1626 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
1630 * The reap timers are started later, with a module init call: That part
1631 * of the kernel is not yet operational.
1635 static int __init cpucache_init(void)
1640 * Register the timers that return unneeded pages to the page allocator
1642 for_each_online_cpu(cpu)
1643 start_cpu_timer(cpu);
1649 __initcall(cpucache_init);
1651 static noinline void
1652 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
1654 struct kmem_cache_node *n;
1656 unsigned long flags;
1660 "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1662 printk(KERN_WARNING " cache: %s, object size: %d, order: %d\n",
1663 cachep->name, cachep->size, cachep->gfporder);
1665 for_each_online_node(node) {
1666 unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
1667 unsigned long active_slabs = 0, num_slabs = 0;
1669 n = cachep->node[node];
1673 spin_lock_irqsave(&n->list_lock, flags);
1674 list_for_each_entry(page, &n->slabs_full, lru) {
1675 active_objs += cachep->num;
1678 list_for_each_entry(page, &n->slabs_partial, lru) {
1679 active_objs += page->active;
1682 list_for_each_entry(page, &n->slabs_free, lru)
1685 free_objects += n->free_objects;
1686 spin_unlock_irqrestore(&n->list_lock, flags);
1688 num_slabs += active_slabs;
1689 num_objs = num_slabs * cachep->num;
1691 " node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
1692 node, active_slabs, num_slabs, active_objs, num_objs,
1698 * Interface to system's page allocator. No need to hold the cache-lock.
1700 * If we requested dmaable memory, we will get it. Even if we
1701 * did not request dmaable memory, we might get it, but that
1702 * would be relatively rare and ignorable.
1704 static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
1710 flags |= cachep->allocflags;
1711 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1712 flags |= __GFP_RECLAIMABLE;
1714 page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1716 if (!(flags & __GFP_NOWARN) && printk_ratelimit())
1717 slab_out_of_memory(cachep, flags, nodeid);
1721 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1722 if (unlikely(page->pfmemalloc))
1723 pfmemalloc_active = true;
1725 nr_pages = (1 << cachep->gfporder);
1726 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1727 add_zone_page_state(page_zone(page),
1728 NR_SLAB_RECLAIMABLE, nr_pages);
1730 add_zone_page_state(page_zone(page),
1731 NR_SLAB_UNRECLAIMABLE, nr_pages);
1732 __SetPageSlab(page);
1733 if (page->pfmemalloc)
1734 SetPageSlabPfmemalloc(page);
1735 memcg_bind_pages(cachep, cachep->gfporder);
1737 if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1738 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1741 kmemcheck_mark_uninitialized_pages(page, nr_pages);
1743 kmemcheck_mark_unallocated_pages(page, nr_pages);
1750 * Interface to system's page release.
1752 static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
1754 const unsigned long nr_freed = (1 << cachep->gfporder);
1756 kmemcheck_free_shadow(page, cachep->gfporder);
1758 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1759 sub_zone_page_state(page_zone(page),
1760 NR_SLAB_RECLAIMABLE, nr_freed);
1762 sub_zone_page_state(page_zone(page),
1763 NR_SLAB_UNRECLAIMABLE, nr_freed);
1765 BUG_ON(!PageSlab(page));
1766 __ClearPageSlabPfmemalloc(page);
1767 __ClearPageSlab(page);
1768 page_mapcount_reset(page);
1769 page->mapping = NULL;
1771 memcg_release_pages(cachep, cachep->gfporder);
1772 if (current->reclaim_state)
1773 current->reclaim_state->reclaimed_slab += nr_freed;
1774 __free_memcg_kmem_pages(page, cachep->gfporder);
1777 static void kmem_rcu_free(struct rcu_head *head)
1779 struct kmem_cache *cachep;
1782 page = container_of(head, struct page, rcu_head);
1783 cachep = page->slab_cache;
1785 kmem_freepages(cachep, page);
1790 #ifdef CONFIG_DEBUG_PAGEALLOC
1791 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1792 unsigned long caller)
1794 int size = cachep->object_size;
1796 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1798 if (size < 5 * sizeof(unsigned long))
1801 *addr++ = 0x12345678;
1803 *addr++ = smp_processor_id();
1804 size -= 3 * sizeof(unsigned long);
1806 unsigned long *sptr = &caller;
1807 unsigned long svalue;
1809 while (!kstack_end(sptr)) {
1811 if (kernel_text_address(svalue)) {
1813 size -= sizeof(unsigned long);
1814 if (size <= sizeof(unsigned long))
1820 *addr++ = 0x87654321;
1824 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1826 int size = cachep->object_size;
1827 addr = &((char *)addr)[obj_offset(cachep)];
1829 memset(addr, val, size);
1830 *(unsigned char *)(addr + size - 1) = POISON_END;
1833 static void dump_line(char *data, int offset, int limit)
1836 unsigned char error = 0;
1839 printk(KERN_ERR "%03x: ", offset);
1840 for (i = 0; i < limit; i++) {
1841 if (data[offset + i] != POISON_FREE) {
1842 error = data[offset + i];
1846 print_hex_dump(KERN_CONT, "", 0, 16, 1,
1847 &data[offset], limit, 1);
1849 if (bad_count == 1) {
1850 error ^= POISON_FREE;
1851 if (!(error & (error - 1))) {
1852 printk(KERN_ERR "Single bit error detected. Probably "
1855 printk(KERN_ERR "Run memtest86+ or a similar memory "
1858 printk(KERN_ERR "Run a memory test tool.\n");
1867 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1872 if (cachep->flags & SLAB_RED_ZONE) {
1873 printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n",
1874 *dbg_redzone1(cachep, objp),
1875 *dbg_redzone2(cachep, objp));
1878 if (cachep->flags & SLAB_STORE_USER) {
1879 printk(KERN_ERR "Last user: [<%p>](%pSR)\n",
1880 *dbg_userword(cachep, objp),
1881 *dbg_userword(cachep, objp));
1883 realobj = (char *)objp + obj_offset(cachep);
1884 size = cachep->object_size;
1885 for (i = 0; i < size && lines; i += 16, lines--) {
1888 if (i + limit > size)
1890 dump_line(realobj, i, limit);
1894 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1900 realobj = (char *)objp + obj_offset(cachep);
1901 size = cachep->object_size;
1903 for (i = 0; i < size; i++) {
1904 char exp = POISON_FREE;
1907 if (realobj[i] != exp) {
1913 "Slab corruption (%s): %s start=%p, len=%d\n",
1914 print_tainted(), cachep->name, realobj, size);
1915 print_objinfo(cachep, objp, 0);
1917 /* Hexdump the affected line */
1920 if (i + limit > size)
1922 dump_line(realobj, i, limit);
1925 /* Limit to 5 lines */
1931 /* Print some data about the neighboring objects, if they
1934 struct page *page = virt_to_head_page(objp);
1937 objnr = obj_to_index(cachep, page, objp);
1939 objp = index_to_obj(cachep, page, objnr - 1);
1940 realobj = (char *)objp + obj_offset(cachep);
1941 printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1943 print_objinfo(cachep, objp, 2);
1945 if (objnr + 1 < cachep->num) {
1946 objp = index_to_obj(cachep, page, objnr + 1);
1947 realobj = (char *)objp + obj_offset(cachep);
1948 printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1950 print_objinfo(cachep, objp, 2);
1957 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1961 for (i = 0; i < cachep->num; i++) {
1962 void *objp = index_to_obj(cachep, page, i);
1964 if (cachep->flags & SLAB_POISON) {
1965 #ifdef CONFIG_DEBUG_PAGEALLOC
1966 if (cachep->size % PAGE_SIZE == 0 &&
1968 kernel_map_pages(virt_to_page(objp),
1969 cachep->size / PAGE_SIZE, 1);
1971 check_poison_obj(cachep, objp);
1973 check_poison_obj(cachep, objp);
1976 if (cachep->flags & SLAB_RED_ZONE) {
1977 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1978 slab_error(cachep, "start of a freed object "
1980 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1981 slab_error(cachep, "end of a freed object "
1987 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1994 * slab_destroy - destroy and release all objects in a slab
1995 * @cachep: cache pointer being destroyed
1996 * @page: page pointer being destroyed
1998 * Destroy all the objs in a slab, and release the mem back to the system.
1999 * Before calling the slab must have been unlinked from the cache. The
2000 * cache-lock is not held/needed.
2002 static void slab_destroy(struct kmem_cache *cachep, struct page *page)
2006 freelist = page->freelist;
2007 slab_destroy_debugcheck(cachep, page);
2008 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
2009 struct rcu_head *head;
2012 * RCU free overloads the RCU head over the LRU.
2013 * slab_page has been overloeaded over the LRU,
2014 * however it is not used from now on so that
2015 * we can use it safely.
2017 head = (void *)&page->rcu_head;
2018 call_rcu(head, kmem_rcu_free);
2021 kmem_freepages(cachep, page);
2025 * From now on, we don't use freelist
2026 * although actual page can be freed in rcu context
2028 if (OFF_SLAB(cachep))
2029 kmem_cache_free(cachep->freelist_cache, freelist);
2033 * calculate_slab_order - calculate size (page order) of slabs
2034 * @cachep: pointer to the cache that is being created
2035 * @size: size of objects to be created in this cache.
2036 * @align: required alignment for the objects.
2037 * @flags: slab allocation flags
2039 * Also calculates the number of objects per slab.
2041 * This could be made much more intelligent. For now, try to avoid using
2042 * high order pages for slabs. When the gfp() functions are more friendly
2043 * towards high-order requests, this should be changed.
2045 static size_t calculate_slab_order(struct kmem_cache *cachep,
2046 size_t size, size_t align, unsigned long flags)
2048 unsigned long offslab_limit;
2049 size_t left_over = 0;
2052 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
2056 cache_estimate(gfporder, size, align, flags, &remainder, &num);
2060 if (flags & CFLGS_OFF_SLAB) {
2061 size_t freelist_size_per_obj = sizeof(unsigned int);
2063 * Max number of objs-per-slab for caches which
2064 * use off-slab slabs. Needed to avoid a possible
2065 * looping condition in cache_grow().
2067 if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
2068 freelist_size_per_obj += sizeof(char);
2069 offslab_limit = size;
2070 offslab_limit /= freelist_size_per_obj;
2072 if (num > offslab_limit)
2076 /* Found something acceptable - save it away */
2078 cachep->gfporder = gfporder;
2079 left_over = remainder;
2082 * A VFS-reclaimable slab tends to have most allocations
2083 * as GFP_NOFS and we really don't want to have to be allocating
2084 * higher-order pages when we are unable to shrink dcache.
2086 if (flags & SLAB_RECLAIM_ACCOUNT)
2090 * Large number of objects is good, but very large slabs are
2091 * currently bad for the gfp()s.
2093 if (gfporder >= slab_max_order)
2097 * Acceptable internal fragmentation?
2099 if (left_over * 8 <= (PAGE_SIZE << gfporder))
2105 static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
2107 if (slab_state >= FULL)
2108 return enable_cpucache(cachep, gfp);
2110 if (slab_state == DOWN) {
2112 * Note: Creation of first cache (kmem_cache).
2113 * The setup_node is taken care
2114 * of by the caller of __kmem_cache_create
2116 cachep->array[smp_processor_id()] = &initarray_generic.cache;
2117 slab_state = PARTIAL;
2118 } else if (slab_state == PARTIAL) {
2120 * Note: the second kmem_cache_create must create the cache
2121 * that's used by kmalloc(24), otherwise the creation of
2122 * further caches will BUG().
2124 cachep->array[smp_processor_id()] = &initarray_generic.cache;
2127 * If the cache that's used by kmalloc(sizeof(kmem_cache_node)) is
2128 * the second cache, then we need to set up all its node/,
2129 * otherwise the creation of further caches will BUG().
2131 set_up_node(cachep, SIZE_AC);
2132 if (INDEX_AC == INDEX_NODE)
2133 slab_state = PARTIAL_NODE;
2135 slab_state = PARTIAL_ARRAYCACHE;
2137 /* Remaining boot caches */
2138 cachep->array[smp_processor_id()] =
2139 kmalloc(sizeof(struct arraycache_init), gfp);
2141 if (slab_state == PARTIAL_ARRAYCACHE) {
2142 set_up_node(cachep, SIZE_NODE);
2143 slab_state = PARTIAL_NODE;
2146 for_each_online_node(node) {
2147 cachep->node[node] =
2148 kmalloc_node(sizeof(struct kmem_cache_node),
2150 BUG_ON(!cachep->node[node]);
2151 kmem_cache_node_init(cachep->node[node]);
2155 cachep->node[numa_mem_id()]->next_reap =
2156 jiffies + REAPTIMEOUT_LIST3 +
2157 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
2159 cpu_cache_get(cachep)->avail = 0;
2160 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
2161 cpu_cache_get(cachep)->batchcount = 1;
2162 cpu_cache_get(cachep)->touched = 0;
2163 cachep->batchcount = 1;
2164 cachep->limit = BOOT_CPUCACHE_ENTRIES;
2169 * __kmem_cache_create - Create a cache.
2170 * @cachep: cache management descriptor
2171 * @flags: SLAB flags
2173 * Returns a ptr to the cache on success, NULL on failure.
2174 * Cannot be called within a int, but can be interrupted.
2175 * The @ctor is run when new pages are allocated by the cache.
2179 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2180 * to catch references to uninitialised memory.
2182 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2183 * for buffer overruns.
2185 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2186 * cacheline. This can be beneficial if you're counting cycles as closely
2190 __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
2192 size_t left_over, freelist_size, ralign;
2195 size_t size = cachep->size;
2200 * Enable redzoning and last user accounting, except for caches with
2201 * large objects, if the increased size would increase the object size
2202 * above the next power of two: caches with object sizes just above a
2203 * power of two have a significant amount of internal fragmentation.
2205 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2206 2 * sizeof(unsigned long long)))
2207 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2208 if (!(flags & SLAB_DESTROY_BY_RCU))
2209 flags |= SLAB_POISON;
2211 if (flags & SLAB_DESTROY_BY_RCU)
2212 BUG_ON(flags & SLAB_POISON);
2216 * Check that size is in terms of words. This is needed to avoid
2217 * unaligned accesses for some archs when redzoning is used, and makes
2218 * sure any on-slab bufctl's are also correctly aligned.
2220 if (size & (BYTES_PER_WORD - 1)) {
2221 size += (BYTES_PER_WORD - 1);
2222 size &= ~(BYTES_PER_WORD - 1);
2226 * Redzoning and user store require word alignment or possibly larger.
2227 * Note this will be overridden by architecture or caller mandated
2228 * alignment if either is greater than BYTES_PER_WORD.
2230 if (flags & SLAB_STORE_USER)
2231 ralign = BYTES_PER_WORD;
2233 if (flags & SLAB_RED_ZONE) {
2234 ralign = REDZONE_ALIGN;
2235 /* If redzoning, ensure that the second redzone is suitably
2236 * aligned, by adjusting the object size accordingly. */
2237 size += REDZONE_ALIGN - 1;
2238 size &= ~(REDZONE_ALIGN - 1);
2241 /* 3) caller mandated alignment */
2242 if (ralign < cachep->align) {
2243 ralign = cachep->align;
2245 /* disable debug if necessary */
2246 if (ralign > __alignof__(unsigned long long))
2247 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2251 cachep->align = ralign;
2253 if (slab_is_available())
2258 setup_node_pointer(cachep);
2262 * Both debugging options require word-alignment which is calculated
2265 if (flags & SLAB_RED_ZONE) {
2266 /* add space for red zone words */
2267 cachep->obj_offset += sizeof(unsigned long long);
2268 size += 2 * sizeof(unsigned long long);
2270 if (flags & SLAB_STORE_USER) {
2271 /* user store requires one word storage behind the end of
2272 * the real object. But if the second red zone needs to be
2273 * aligned to 64 bits, we must allow that much space.
2275 if (flags & SLAB_RED_ZONE)
2276 size += REDZONE_ALIGN;
2278 size += BYTES_PER_WORD;
2280 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2281 if (size >= kmalloc_size(INDEX_NODE + 1)
2282 && cachep->object_size > cache_line_size()
2283 && ALIGN(size, cachep->align) < PAGE_SIZE) {
2284 cachep->obj_offset += PAGE_SIZE - ALIGN(size, cachep->align);
2291 * Determine if the slab management is 'on' or 'off' slab.
2292 * (bootstrapping cannot cope with offslab caches so don't do
2293 * it too early on. Always use on-slab management when
2294 * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
2296 if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init &&
2297 !(flags & SLAB_NOLEAKTRACE))
2299 * Size is large, assume best to place the slab management obj
2300 * off-slab (should allow better packing of objs).
2302 flags |= CFLGS_OFF_SLAB;
2304 size = ALIGN(size, cachep->align);
2306 left_over = calculate_slab_order(cachep, size, cachep->align, flags);
2311 freelist_size = calculate_freelist_size(cachep->num, cachep->align);
2314 * If the slab has been placed off-slab, and we have enough space then
2315 * move it on-slab. This is at the expense of any extra colouring.
2317 if (flags & CFLGS_OFF_SLAB && left_over >= freelist_size) {
2318 flags &= ~CFLGS_OFF_SLAB;
2319 left_over -= freelist_size;
2322 if (flags & CFLGS_OFF_SLAB) {
2323 /* really off slab. No need for manual alignment */
2324 freelist_size = calculate_freelist_size(cachep->num, 0);
2326 #ifdef CONFIG_PAGE_POISONING
2327 /* If we're going to use the generic kernel_map_pages()
2328 * poisoning, then it's going to smash the contents of
2329 * the redzone and userword anyhow, so switch them off.
2331 if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
2332 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2336 cachep->colour_off = cache_line_size();
2337 /* Offset must be a multiple of the alignment. */
2338 if (cachep->colour_off < cachep->align)
2339 cachep->colour_off = cachep->align;
2340 cachep->colour = left_over / cachep->colour_off;
2341 cachep->freelist_size = freelist_size;
2342 cachep->flags = flags;
2343 cachep->allocflags = __GFP_COMP;
2344 if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
2345 cachep->allocflags |= GFP_DMA;
2346 cachep->size = size;
2347 cachep->reciprocal_buffer_size = reciprocal_value(size);
2349 if (flags & CFLGS_OFF_SLAB) {
2350 cachep->freelist_cache = kmalloc_slab(freelist_size, 0u);
2352 * This is a possibility for one of the malloc_sizes caches.
2353 * But since we go off slab only for object size greater than
2354 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2355 * this should not happen at all.
2356 * But leave a BUG_ON for some lucky dude.
2358 BUG_ON(ZERO_OR_NULL_PTR(cachep->freelist_cache));
2361 err = setup_cpu_cache(cachep, gfp);
2363 __kmem_cache_shutdown(cachep);
2367 if (flags & SLAB_DEBUG_OBJECTS) {
2369 * Would deadlock through slab_destroy()->call_rcu()->
2370 * debug_object_activate()->kmem_cache_alloc().
2372 WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
2374 slab_set_debugobj_lock_classes(cachep);
2375 } else if (!OFF_SLAB(cachep) && !(flags & SLAB_DESTROY_BY_RCU))
2376 on_slab_lock_classes(cachep);
2382 static void check_irq_off(void)
2384 BUG_ON(!irqs_disabled());
2387 static void check_irq_on(void)
2389 BUG_ON(irqs_disabled());
2392 static void check_spinlock_acquired(struct kmem_cache *cachep)
2396 assert_spin_locked(&cachep->node[numa_mem_id()]->list_lock);
2400 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2404 assert_spin_locked(&cachep->node[node]->list_lock);
2409 #define check_irq_off() do { } while(0)
2410 #define check_irq_on() do { } while(0)
2411 #define check_spinlock_acquired(x) do { } while(0)
2412 #define check_spinlock_acquired_node(x, y) do { } while(0)
2415 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
2416 struct array_cache *ac,
2417 int force, int node);
2419 static void do_drain(void *arg)
2421 struct kmem_cache *cachep = arg;
2422 struct array_cache *ac;
2423 int node = numa_mem_id();
2426 ac = cpu_cache_get(cachep);
2427 spin_lock(&cachep->node[node]->list_lock);
2428 free_block(cachep, ac->entry, ac->avail, node);
2429 spin_unlock(&cachep->node[node]->list_lock);
2433 static void drain_cpu_caches(struct kmem_cache *cachep)
2435 struct kmem_cache_node *n;
2438 on_each_cpu(do_drain, cachep, 1);
2440 for_each_online_node(node) {
2441 n = cachep->node[node];
2443 drain_alien_cache(cachep, n->alien);
2446 for_each_online_node(node) {
2447 n = cachep->node[node];
2449 drain_array(cachep, n, n->shared, 1, node);
2454 * Remove slabs from the list of free slabs.
2455 * Specify the number of slabs to drain in tofree.
2457 * Returns the actual number of slabs released.
2459 static int drain_freelist(struct kmem_cache *cache,
2460 struct kmem_cache_node *n, int tofree)
2462 struct list_head *p;
2467 while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
2469 spin_lock_irq(&n->list_lock);
2470 p = n->slabs_free.prev;
2471 if (p == &n->slabs_free) {
2472 spin_unlock_irq(&n->list_lock);
2476 page = list_entry(p, struct page, lru);
2478 BUG_ON(page->active);
2480 list_del(&page->lru);
2482 * Safe to drop the lock. The slab is no longer linked
2485 n->free_objects -= cache->num;
2486 spin_unlock_irq(&n->list_lock);
2487 slab_destroy(cache, page);
2494 /* Called with slab_mutex held to protect against cpu hotplug */
2495 static int __cache_shrink(struct kmem_cache *cachep)
2498 struct kmem_cache_node *n;
2500 drain_cpu_caches(cachep);
2503 for_each_online_node(i) {
2504 n = cachep->node[i];
2508 drain_freelist(cachep, n, slabs_tofree(cachep, n));
2510 ret += !list_empty(&n->slabs_full) ||
2511 !list_empty(&n->slabs_partial);
2513 return (ret ? 1 : 0);
2517 * kmem_cache_shrink - Shrink a cache.
2518 * @cachep: The cache to shrink.
2520 * Releases as many slabs as possible for a cache.
2521 * To help debugging, a zero exit status indicates all slabs were released.
2523 int kmem_cache_shrink(struct kmem_cache *cachep)
2526 BUG_ON(!cachep || in_interrupt());
2529 mutex_lock(&slab_mutex);
2530 ret = __cache_shrink(cachep);
2531 mutex_unlock(&slab_mutex);
2535 EXPORT_SYMBOL(kmem_cache_shrink);
2537 int __kmem_cache_shutdown(struct kmem_cache *cachep)
2540 struct kmem_cache_node *n;
2541 int rc = __cache_shrink(cachep);
2546 for_each_online_cpu(i)
2547 kfree(cachep->array[i]);
2549 /* NUMA: free the node structures */
2550 for_each_online_node(i) {
2551 n = cachep->node[i];
2554 free_alien_cache(n->alien);
2562 * Get the memory for a slab management obj.
2563 * For a slab cache when the slab descriptor is off-slab, slab descriptors
2564 * always come from malloc_sizes caches. The slab descriptor cannot
2565 * come from the same cache which is getting created because,
2566 * when we are searching for an appropriate cache for these
2567 * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2568 * If we are creating a malloc_sizes cache here it would not be visible to
2569 * kmem_find_general_cachep till the initialization is complete.
2570 * Hence we cannot have freelist_cache same as the original cache.
2572 static void *alloc_slabmgmt(struct kmem_cache *cachep,
2573 struct page *page, int colour_off,
2574 gfp_t local_flags, int nodeid)
2577 void *addr = page_address(page);
2579 if (OFF_SLAB(cachep)) {
2580 /* Slab management obj is off-slab. */
2581 freelist = kmem_cache_alloc_node(cachep->freelist_cache,
2582 local_flags, nodeid);
2586 freelist = addr + colour_off;
2587 colour_off += cachep->freelist_size;
2590 page->s_mem = addr + colour_off;
2594 static inline unsigned int *slab_freelist(struct page *page)
2596 return (unsigned int *)(page->freelist);
2599 static void cache_init_objs(struct kmem_cache *cachep,
2604 for (i = 0; i < cachep->num; i++) {
2605 void *objp = index_to_obj(cachep, page, i);
2607 /* need to poison the objs? */
2608 if (cachep->flags & SLAB_POISON)
2609 poison_obj(cachep, objp, POISON_FREE);
2610 if (cachep->flags & SLAB_STORE_USER)
2611 *dbg_userword(cachep, objp) = NULL;
2613 if (cachep->flags & SLAB_RED_ZONE) {
2614 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2615 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2618 * Constructors are not allowed to allocate memory from the same
2619 * cache which they are a constructor for. Otherwise, deadlock.
2620 * They must also be threaded.
2622 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2623 cachep->ctor(objp + obj_offset(cachep));
2625 if (cachep->flags & SLAB_RED_ZONE) {
2626 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2627 slab_error(cachep, "constructor overwrote the"
2628 " end of an object");
2629 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2630 slab_error(cachep, "constructor overwrote the"
2631 " start of an object");
2633 if ((cachep->size % PAGE_SIZE) == 0 &&
2634 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2635 kernel_map_pages(virt_to_page(objp),
2636 cachep->size / PAGE_SIZE, 0);
2641 set_obj_status(page, i, OBJECT_FREE);
2642 slab_freelist(page)[i] = i;
2646 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2648 if (CONFIG_ZONE_DMA_FLAG) {
2649 if (flags & GFP_DMA)
2650 BUG_ON(!(cachep->allocflags & GFP_DMA));
2652 BUG_ON(cachep->allocflags & GFP_DMA);
2656 static void *slab_get_obj(struct kmem_cache *cachep, struct page *page,
2661 objp = index_to_obj(cachep, page, slab_freelist(page)[page->active]);
2664 WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);
2670 static void slab_put_obj(struct kmem_cache *cachep, struct page *page,
2671 void *objp, int nodeid)
2673 unsigned int objnr = obj_to_index(cachep, page, objp);
2677 /* Verify that the slab belongs to the intended node */
2678 WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);
2680 /* Verify double free bug */
2681 for (i = page->active; i < cachep->num; i++) {
2682 if (slab_freelist(page)[i] == objnr) {
2683 printk(KERN_ERR "slab: double free detected in cache "
2684 "'%s', objp %p\n", cachep->name, objp);
2690 slab_freelist(page)[page->active] = objnr;
2694 * Map pages beginning at addr to the given cache and slab. This is required
2695 * for the slab allocator to be able to lookup the cache and slab of a
2696 * virtual address for kfree, ksize, and slab debugging.
2698 static void slab_map_pages(struct kmem_cache *cache, struct page *page,
2701 page->slab_cache = cache;
2702 page->freelist = freelist;
2706 * Grow (by 1) the number of slabs within a cache. This is called by
2707 * kmem_cache_alloc() when there are no active objs left in a cache.
2709 static int cache_grow(struct kmem_cache *cachep,
2710 gfp_t flags, int nodeid, struct page *page)
2715 struct kmem_cache_node *n;
2718 * Be lazy and only check for valid flags here, keeping it out of the
2719 * critical path in kmem_cache_alloc().
2721 BUG_ON(flags & GFP_SLAB_BUG_MASK);
2722 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2724 /* Take the node list lock to change the colour_next on this node */
2726 n = cachep->node[nodeid];
2727 spin_lock(&n->list_lock);
2729 /* Get colour for the slab, and cal the next value. */
2730 offset = n->colour_next;
2732 if (n->colour_next >= cachep->colour)
2734 spin_unlock(&n->list_lock);
2736 offset *= cachep->colour_off;
2738 if (local_flags & __GFP_WAIT)
2742 * The test for missing atomic flag is performed here, rather than
2743 * the more obvious place, simply to reduce the critical path length
2744 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2745 * will eventually be caught here (where it matters).
2747 kmem_flagcheck(cachep, flags);
2750 * Get mem for the objs. Attempt to allocate a physical page from
2754 page = kmem_getpages(cachep, local_flags, nodeid);
2758 /* Get slab management. */
2759 freelist = alloc_slabmgmt(cachep, page, offset,
2760 local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
2764 slab_map_pages(cachep, page, freelist);
2766 cache_init_objs(cachep, page);
2768 if (local_flags & __GFP_WAIT)
2769 local_irq_disable();
2771 spin_lock(&n->list_lock);
2773 /* Make slab active. */
2774 list_add_tail(&page->lru, &(n->slabs_free));
2775 STATS_INC_GROWN(cachep);
2776 n->free_objects += cachep->num;
2777 spin_unlock(&n->list_lock);
2780 kmem_freepages(cachep, page);
2782 if (local_flags & __GFP_WAIT)
2783 local_irq_disable();
2790 * Perform extra freeing checks:
2791 * - detect bad pointers.
2792 * - POISON/RED_ZONE checking
2794 static void kfree_debugcheck(const void *objp)
2796 if (!virt_addr_valid(objp)) {
2797 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2798 (unsigned long)objp);
2803 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2805 unsigned long long redzone1, redzone2;
2807 redzone1 = *dbg_redzone1(cache, obj);
2808 redzone2 = *dbg_redzone2(cache, obj);
2813 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2816 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2817 slab_error(cache, "double free detected");
2819 slab_error(cache, "memory outside object was overwritten");
2821 printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
2822 obj, redzone1, redzone2);
2825 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2826 unsigned long caller)
2831 BUG_ON(virt_to_cache(objp) != cachep);
2833 objp -= obj_offset(cachep);
2834 kfree_debugcheck(objp);
2835 page = virt_to_head_page(objp);
2837 if (cachep->flags & SLAB_RED_ZONE) {
2838 verify_redzone_free(cachep, objp);
2839 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2840 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2842 if (cachep->flags & SLAB_STORE_USER)
2843 *dbg_userword(cachep, objp) = (void *)caller;
2845 objnr = obj_to_index(cachep, page, objp);
2847 BUG_ON(objnr >= cachep->num);
2848 BUG_ON(objp != index_to_obj(cachep, page, objnr));
2850 set_obj_status(page, objnr, OBJECT_FREE);
2851 if (cachep->flags & SLAB_POISON) {
2852 #ifdef CONFIG_DEBUG_PAGEALLOC
2853 if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2854 store_stackinfo(cachep, objp, caller);
2855 kernel_map_pages(virt_to_page(objp),
2856 cachep->size / PAGE_SIZE, 0);
2858 poison_obj(cachep, objp, POISON_FREE);
2861 poison_obj(cachep, objp, POISON_FREE);
2868 #define kfree_debugcheck(x) do { } while(0)
2869 #define cache_free_debugcheck(x,objp,z) (objp)
2872 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags,
2876 struct kmem_cache_node *n;
2877 struct array_cache *ac;
2881 node = numa_mem_id();
2882 if (unlikely(force_refill))
2885 ac = cpu_cache_get(cachep);
2886 batchcount = ac->batchcount;
2887 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2889 * If there was little recent activity on this cache, then
2890 * perform only a partial refill. Otherwise we could generate
2893 batchcount = BATCHREFILL_LIMIT;
2895 n = cachep->node[node];
2897 BUG_ON(ac->avail > 0 || !n);
2898 spin_lock(&n->list_lock);
2900 /* See if we can refill from the shared array */
2901 if (n->shared && transfer_objects(ac, n->shared, batchcount)) {
2902 n->shared->touched = 1;
2906 while (batchcount > 0) {
2907 struct list_head *entry;
2909 /* Get slab alloc is to come from. */
2910 entry = n->slabs_partial.next;
2911 if (entry == &n->slabs_partial) {
2912 n->free_touched = 1;
2913 entry = n->slabs_free.next;
2914 if (entry == &n->slabs_free)
2918 page = list_entry(entry, struct page, lru);
2919 check_spinlock_acquired(cachep);
2922 * The slab was either on partial or free list so
2923 * there must be at least one object available for
2926 BUG_ON(page->active >= cachep->num);
2928 while (page->active < cachep->num && batchcount--) {
2929 STATS_INC_ALLOCED(cachep);
2930 STATS_INC_ACTIVE(cachep);
2931 STATS_SET_HIGH(cachep);
2933 ac_put_obj(cachep, ac, slab_get_obj(cachep, page,
2937 /* move slabp to correct slabp list: */
2938 list_del(&page->lru);
2939 if (page->active == cachep->num)
2940 list_add(&page->list, &n->slabs_full);
2942 list_add(&page->list, &n->slabs_partial);
2946 n->free_objects -= ac->avail;
2948 spin_unlock(&n->list_lock);
2950 if (unlikely(!ac->avail)) {
2953 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
2955 /* cache_grow can reenable interrupts, then ac could change. */
2956 ac = cpu_cache_get(cachep);
2957 node = numa_mem_id();
2959 /* no objects in sight? abort */
2960 if (!x && (ac->avail == 0 || force_refill))
2963 if (!ac->avail) /* objects refilled by interrupt? */
2968 return ac_get_obj(cachep, ac, flags, force_refill);
2971 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
2974 might_sleep_if(flags & __GFP_WAIT);
2976 kmem_flagcheck(cachep, flags);
2981 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
2982 gfp_t flags, void *objp, unsigned long caller)
2988 if (cachep->flags & SLAB_POISON) {
2989 #ifdef CONFIG_DEBUG_PAGEALLOC
2990 if ((cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
2991 kernel_map_pages(virt_to_page(objp),
2992 cachep->size / PAGE_SIZE, 1);
2994 check_poison_obj(cachep, objp);
2996 check_poison_obj(cachep, objp);
2998 poison_obj(cachep, objp, POISON_INUSE);
3000 if (cachep->flags & SLAB_STORE_USER)
3001 *dbg_userword(cachep, objp) = (void *)caller;
3003 if (cachep->flags & SLAB_RED_ZONE) {
3004 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
3005 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
3006 slab_error(cachep, "double free, or memory outside"
3007 " object was overwritten");
3009 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3010 objp, *dbg_redzone1(cachep, objp),
3011 *dbg_redzone2(cachep, objp));
3013 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
3014 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
3017 page = virt_to_head_page(objp);
3018 set_obj_status(page, obj_to_index(cachep, page, objp), OBJECT_ACTIVE);
3019 objp += obj_offset(cachep);
3020 if (cachep->ctor && cachep->flags & SLAB_POISON)
3022 if (ARCH_SLAB_MINALIGN &&
3023 ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
3024 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3025 objp, (int)ARCH_SLAB_MINALIGN);
3030 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3033 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
3035 if (cachep == kmem_cache)
3038 return should_failslab(cachep->object_size, flags, cachep->flags);
3041 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3044 struct array_cache *ac;
3045 bool force_refill = false;
3049 ac = cpu_cache_get(cachep);
3050 if (likely(ac->avail)) {
3052 objp = ac_get_obj(cachep, ac, flags, false);
3055 * Allow for the possibility all avail objects are not allowed
3056 * by the current flags
3059 STATS_INC_ALLOCHIT(cachep);
3062 force_refill = true;
3065 STATS_INC_ALLOCMISS(cachep);
3066 objp = cache_alloc_refill(cachep, flags, force_refill);
3068 * the 'ac' may be updated by cache_alloc_refill(),
3069 * and kmemleak_erase() requires its correct value.
3071 ac = cpu_cache_get(cachep);
3075 * To avoid a false negative, if an object that is in one of the
3076 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3077 * treat the array pointers as a reference to the object.
3080 kmemleak_erase(&ac->entry[ac->avail]);
3086 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3088 * If we are in_interrupt, then process context, including cpusets and
3089 * mempolicy, may not apply and should not be used for allocation policy.
3091 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3093 int nid_alloc, nid_here;
3095 if (in_interrupt() || (flags & __GFP_THISNODE))
3097 nid_alloc = nid_here = numa_mem_id();
3098 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3099 nid_alloc = cpuset_slab_spread_node();
3100 else if (current->mempolicy)
3101 nid_alloc = slab_node();
3102 if (nid_alloc != nid_here)
3103 return ____cache_alloc_node(cachep, flags, nid_alloc);
3108 * Fallback function if there was no memory available and no objects on a
3109 * certain node and fall back is permitted. First we scan all the
3110 * available node for available objects. If that fails then we
3111 * perform an allocation without specifying a node. This allows the page
3112 * allocator to do its reclaim / fallback magic. We then insert the
3113 * slab into the proper nodelist and then allocate from it.
3115 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3117 struct zonelist *zonelist;
3121 enum zone_type high_zoneidx = gfp_zone(flags);
3124 unsigned int cpuset_mems_cookie;
3126 if (flags & __GFP_THISNODE)
3129 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
3132 cpuset_mems_cookie = get_mems_allowed();
3133 zonelist = node_zonelist(slab_node(), flags);
3137 * Look through allowed nodes for objects available
3138 * from existing per node queues.
3140 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3141 nid = zone_to_nid(zone);
3143 if (cpuset_zone_allowed_hardwall(zone, flags) &&
3145 cache->node[nid]->free_objects) {
3146 obj = ____cache_alloc_node(cache,
3147 flags | GFP_THISNODE, nid);
3155 * This allocation will be performed within the constraints
3156 * of the current cpuset / memory policy requirements.
3157 * We may trigger various forms of reclaim on the allowed
3158 * set and go into memory reserves if necessary.
3162 if (local_flags & __GFP_WAIT)
3164 kmem_flagcheck(cache, flags);
3165 page = kmem_getpages(cache, local_flags, numa_mem_id());
3166 if (local_flags & __GFP_WAIT)
3167 local_irq_disable();
3170 * Insert into the appropriate per node queues
3172 nid = page_to_nid(page);
3173 if (cache_grow(cache, flags, nid, page)) {
3174 obj = ____cache_alloc_node(cache,
3175 flags | GFP_THISNODE, nid);
3178 * Another processor may allocate the
3179 * objects in the slab since we are
3180 * not holding any locks.
3184 /* cache_grow already freed obj */
3190 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !obj))
3196 * A interface to enable slab creation on nodeid
3198 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3201 struct list_head *entry;
3203 struct kmem_cache_node *n;
3207 VM_BUG_ON(nodeid > num_online_nodes());
3208 n = cachep->node[nodeid];
3213 spin_lock(&n->list_lock);
3214 entry = n->slabs_partial.next;
3215 if (entry == &n->slabs_partial) {
3216 n->free_touched = 1;
3217 entry = n->slabs_free.next;
3218 if (entry == &n->slabs_free)
3222 page = list_entry(entry, struct page, lru);
3223 check_spinlock_acquired_node(cachep, nodeid);
3225 STATS_INC_NODEALLOCS(cachep);
3226 STATS_INC_ACTIVE(cachep);
3227 STATS_SET_HIGH(cachep);
3229 BUG_ON(page->active == cachep->num);
3231 obj = slab_get_obj(cachep, page, nodeid);
3233 /* move slabp to correct slabp list: */
3234 list_del(&page->lru);
3236 if (page->active == cachep->num)
3237 list_add(&page->lru, &n->slabs_full);
3239 list_add(&page->lru, &n->slabs_partial);
3241 spin_unlock(&n->list_lock);
3245 spin_unlock(&n->list_lock);
3246 x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
3250 return fallback_alloc(cachep, flags);
3256 static __always_inline void *
3257 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3258 unsigned long caller)
3260 unsigned long save_flags;
3262 int slab_node = numa_mem_id();
3264 flags &= gfp_allowed_mask;
3266 lockdep_trace_alloc(flags);
3268 if (slab_should_failslab(cachep, flags))
3271 cachep = memcg_kmem_get_cache(cachep, flags);
3273 cache_alloc_debugcheck_before(cachep, flags);
3274 local_irq_save(save_flags);
3276 if (nodeid == NUMA_NO_NODE)
3279 if (unlikely(!cachep->node[nodeid])) {
3280 /* Node not bootstrapped yet */
3281 ptr = fallback_alloc(cachep, flags);
3285 if (nodeid == slab_node) {
3287 * Use the locally cached objects if possible.
3288 * However ____cache_alloc does not allow fallback
3289 * to other nodes. It may fail while we still have
3290 * objects on other nodes available.
3292 ptr = ____cache_alloc(cachep, flags);
3296 /* ___cache_alloc_node can fall back to other nodes */
3297 ptr = ____cache_alloc_node(cachep, flags, nodeid);
3299 local_irq_restore(save_flags);
3300 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3301 kmemleak_alloc_recursive(ptr, cachep->object_size, 1, cachep->flags,
3305 kmemcheck_slab_alloc(cachep, flags, ptr, cachep->object_size);
3307 if (unlikely((flags & __GFP_ZERO) && ptr))
3308 memset(ptr, 0, cachep->object_size);
3313 static __always_inline void *
3314 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3318 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
3319 objp = alternate_node_alloc(cache, flags);
3323 objp = ____cache_alloc(cache, flags);
3326 * We may just have run out of memory on the local node.
3327 * ____cache_alloc_node() knows how to locate memory on other nodes
3330 objp = ____cache_alloc_node(cache, flags, numa_mem_id());
3337 static __always_inline void *
3338 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3340 return ____cache_alloc(cachep, flags);
3343 #endif /* CONFIG_NUMA */
3345 static __always_inline void *
3346 slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
3348 unsigned long save_flags;
3351 flags &= gfp_allowed_mask;
3353 lockdep_trace_alloc(flags);
3355 if (slab_should_failslab(cachep, flags))
3358 cachep = memcg_kmem_get_cache(cachep, flags);
3360 cache_alloc_debugcheck_before(cachep, flags);
3361 local_irq_save(save_flags);
3362 objp = __do_cache_alloc(cachep, flags);
3363 local_irq_restore(save_flags);
3364 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3365 kmemleak_alloc_recursive(objp, cachep->object_size, 1, cachep->flags,
3370 kmemcheck_slab_alloc(cachep, flags, objp, cachep->object_size);
3372 if (unlikely((flags & __GFP_ZERO) && objp))
3373 memset(objp, 0, cachep->object_size);
3379 * Caller needs to acquire correct kmem_list's list_lock
3381 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
3385 struct kmem_cache_node *n;
3387 for (i = 0; i < nr_objects; i++) {
3391 clear_obj_pfmemalloc(&objpp[i]);
3394 page = virt_to_head_page(objp);
3395 n = cachep->node[node];
3396 list_del(&page->lru);
3397 check_spinlock_acquired_node(cachep, node);
3398 slab_put_obj(cachep, page, objp, node);
3399 STATS_DEC_ACTIVE(cachep);
3402 /* fixup slab chains */
3403 if (page->active == 0) {
3404 if (n->free_objects > n->free_limit) {
3405 n->free_objects -= cachep->num;
3406 /* No need to drop any previously held
3407 * lock here, even if we have a off-slab slab
3408 * descriptor it is guaranteed to come from
3409 * a different cache, refer to comments before
3412 slab_destroy(cachep, page);
3414 list_add(&page->lru, &n->slabs_free);
3417 /* Unconditionally move a slab to the end of the
3418 * partial list on free - maximum time for the
3419 * other objects to be freed, too.
3421 list_add_tail(&page->lru, &n->slabs_partial);
3426 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3429 struct kmem_cache_node *n;
3430 int node = numa_mem_id();
3432 batchcount = ac->batchcount;
3434 BUG_ON(!batchcount || batchcount > ac->avail);
3437 n = cachep->node[node];
3438 spin_lock(&n->list_lock);
3440 struct array_cache *shared_array = n->shared;
3441 int max = shared_array->limit - shared_array->avail;
3443 if (batchcount > max)
3445 memcpy(&(shared_array->entry[shared_array->avail]),
3446 ac->entry, sizeof(void *) * batchcount);
3447 shared_array->avail += batchcount;
3452 free_block(cachep, ac->entry, batchcount, node);
3457 struct list_head *p;
3459 p = n->slabs_free.next;
3460 while (p != &(n->slabs_free)) {
3463 page = list_entry(p, struct page, lru);
3464 BUG_ON(page->active);
3469 STATS_SET_FREEABLE(cachep, i);
3472 spin_unlock(&n->list_lock);
3473 ac->avail -= batchcount;
3474 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3478 * Release an obj back to its cache. If the obj has a constructed state, it must
3479 * be in this state _before_ it is released. Called with disabled ints.
3481 static inline void __cache_free(struct kmem_cache *cachep, void *objp,
3482 unsigned long caller)
3484 struct array_cache *ac = cpu_cache_get(cachep);
3487 kmemleak_free_recursive(objp, cachep->flags);
3488 objp = cache_free_debugcheck(cachep, objp, caller);
3490 kmemcheck_slab_free(cachep, objp, cachep->object_size);
3493 * Skip calling cache_free_alien() when the platform is not numa.
3494 * This will avoid cache misses that happen while accessing slabp (which
3495 * is per page memory reference) to get nodeid. Instead use a global
3496 * variable to skip the call, which is mostly likely to be present in
3499 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3502 if (likely(ac->avail < ac->limit)) {
3503 STATS_INC_FREEHIT(cachep);
3505 STATS_INC_FREEMISS(cachep);
3506 cache_flusharray(cachep, ac);
3509 ac_put_obj(cachep, ac, objp);
3513 * kmem_cache_alloc - Allocate an object
3514 * @cachep: The cache to allocate from.
3515 * @flags: See kmalloc().
3517 * Allocate an object from this cache. The flags are only relevant
3518 * if the cache has no available objects.
3520 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3522 void *ret = slab_alloc(cachep, flags, _RET_IP_);
3524 trace_kmem_cache_alloc(_RET_IP_, ret,
3525 cachep->object_size, cachep->size, flags);
3529 EXPORT_SYMBOL(kmem_cache_alloc);
3531 #ifdef CONFIG_TRACING
3533 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
3537 ret = slab_alloc(cachep, flags, _RET_IP_);
3539 trace_kmalloc(_RET_IP_, ret,
3540 size, cachep->size, flags);
3543 EXPORT_SYMBOL(kmem_cache_alloc_trace);
3548 * kmem_cache_alloc_node - Allocate an object on the specified node
3549 * @cachep: The cache to allocate from.
3550 * @flags: See kmalloc().
3551 * @nodeid: node number of the target node.
3553 * Identical to kmem_cache_alloc but it will allocate memory on the given
3554 * node, which can improve the performance for cpu bound structures.
3556 * Fallback to other node is possible if __GFP_THISNODE is not set.
3558 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3560 void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3562 trace_kmem_cache_alloc_node(_RET_IP_, ret,
3563 cachep->object_size, cachep->size,
3568 EXPORT_SYMBOL(kmem_cache_alloc_node);
3570 #ifdef CONFIG_TRACING
3571 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
3578 ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3580 trace_kmalloc_node(_RET_IP_, ret,
3585 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3588 static __always_inline void *
3589 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
3591 struct kmem_cache *cachep;
3593 cachep = kmalloc_slab(size, flags);
3594 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3596 return kmem_cache_alloc_node_trace(cachep, flags, node, size);
3599 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3600 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3602 return __do_kmalloc_node(size, flags, node, _RET_IP_);
3604 EXPORT_SYMBOL(__kmalloc_node);
3606 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3607 int node, unsigned long caller)
3609 return __do_kmalloc_node(size, flags, node, caller);
3611 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3613 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3615 return __do_kmalloc_node(size, flags, node, 0);
3617 EXPORT_SYMBOL(__kmalloc_node);
3618 #endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */
3619 #endif /* CONFIG_NUMA */
3622 * __do_kmalloc - allocate memory
3623 * @size: how many bytes of memory are required.
3624 * @flags: the type of memory to allocate (see kmalloc).
3625 * @caller: function caller for debug tracking of the caller
3627 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3628 unsigned long caller)
3630 struct kmem_cache *cachep;
3633 /* If you want to save a few bytes .text space: replace
3635 * Then kmalloc uses the uninlined functions instead of the inline
3638 cachep = kmalloc_slab(size, flags);
3639 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3641 ret = slab_alloc(cachep, flags, caller);
3643 trace_kmalloc(caller, ret,
3644 size, cachep->size, flags);
3650 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3651 void *__kmalloc(size_t size, gfp_t flags)
3653 return __do_kmalloc(size, flags, _RET_IP_);
3655 EXPORT_SYMBOL(__kmalloc);
3657 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3659 return __do_kmalloc(size, flags, caller);
3661 EXPORT_SYMBOL(__kmalloc_track_caller);
3664 void *__kmalloc(size_t size, gfp_t flags)
3666 return __do_kmalloc(size, flags, 0);
3668 EXPORT_SYMBOL(__kmalloc);
3672 * kmem_cache_free - Deallocate an object
3673 * @cachep: The cache the allocation was from.
3674 * @objp: The previously allocated object.
3676 * Free an object which was previously allocated from this
3679 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3681 unsigned long flags;
3682 cachep = cache_from_obj(cachep, objp);
3686 local_irq_save(flags);
3687 debug_check_no_locks_freed(objp, cachep->object_size);
3688 if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3689 debug_check_no_obj_freed(objp, cachep->object_size);
3690 __cache_free(cachep, objp, _RET_IP_);
3691 local_irq_restore(flags);
3693 trace_kmem_cache_free(_RET_IP_, objp);
3695 EXPORT_SYMBOL(kmem_cache_free);
3698 * kfree - free previously allocated memory
3699 * @objp: pointer returned by kmalloc.
3701 * If @objp is NULL, no operation is performed.
3703 * Don't free memory not originally allocated by kmalloc()
3704 * or you will run into trouble.
3706 void kfree(const void *objp)
3708 struct kmem_cache *c;
3709 unsigned long flags;
3711 trace_kfree(_RET_IP_, objp);
3713 if (unlikely(ZERO_OR_NULL_PTR(objp)))
3715 local_irq_save(flags);
3716 kfree_debugcheck(objp);
3717 c = virt_to_cache(objp);
3718 debug_check_no_locks_freed(objp, c->object_size);
3720 debug_check_no_obj_freed(objp, c->object_size);
3721 __cache_free(c, (void *)objp, _RET_IP_);
3722 local_irq_restore(flags);
3724 EXPORT_SYMBOL(kfree);
3727 * This initializes kmem_cache_node or resizes various caches for all nodes.
3729 static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
3732 struct kmem_cache_node *n;
3733 struct array_cache *new_shared;
3734 struct array_cache **new_alien = NULL;
3736 for_each_online_node(node) {
3738 if (use_alien_caches) {
3739 new_alien = alloc_alien_cache(node, cachep->limit, gfp);
3745 if (cachep->shared) {
3746 new_shared = alloc_arraycache(node,
3747 cachep->shared*cachep->batchcount,
3750 free_alien_cache(new_alien);
3755 n = cachep->node[node];
3757 struct array_cache *shared = n->shared;
3759 spin_lock_irq(&n->list_lock);
3762 free_block(cachep, shared->entry,
3763 shared->avail, node);
3765 n->shared = new_shared;
3767 n->alien = new_alien;
3770 n->free_limit = (1 + nr_cpus_node(node)) *
3771 cachep->batchcount + cachep->num;
3772 spin_unlock_irq(&n->list_lock);
3774 free_alien_cache(new_alien);
3777 n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
3779 free_alien_cache(new_alien);
3784 kmem_cache_node_init(n);
3785 n->next_reap = jiffies + REAPTIMEOUT_LIST3 +
3786 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
3787 n->shared = new_shared;
3788 n->alien = new_alien;
3789 n->free_limit = (1 + nr_cpus_node(node)) *
3790 cachep->batchcount + cachep->num;
3791 cachep->node[node] = n;
3796 if (!cachep->list.next) {
3797 /* Cache is not active yet. Roll back what we did */
3800 if (cachep->node[node]) {
3801 n = cachep->node[node];
3804 free_alien_cache(n->alien);
3806 cachep->node[node] = NULL;
3814 struct ccupdate_struct {
3815 struct kmem_cache *cachep;
3816 struct array_cache *new[0];
3819 static void do_ccupdate_local(void *info)
3821 struct ccupdate_struct *new = info;
3822 struct array_cache *old;
3825 old = cpu_cache_get(new->cachep);
3827 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
3828 new->new[smp_processor_id()] = old;
3831 /* Always called with the slab_mutex held */
3832 static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
3833 int batchcount, int shared, gfp_t gfp)
3835 struct ccupdate_struct *new;
3838 new = kzalloc(sizeof(*new) + nr_cpu_ids * sizeof(struct array_cache *),
3843 for_each_online_cpu(i) {
3844 new->new[i] = alloc_arraycache(cpu_to_mem(i), limit,
3847 for (i--; i >= 0; i--)
3853 new->cachep = cachep;
3855 on_each_cpu(do_ccupdate_local, (void *)new, 1);
3858 cachep->batchcount = batchcount;
3859 cachep->limit = limit;
3860 cachep->shared = shared;
3862 for_each_online_cpu(i) {
3863 struct array_cache *ccold = new->new[i];
3866 spin_lock_irq(&cachep->node[cpu_to_mem(i)]->list_lock);
3867 free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i));
3868 spin_unlock_irq(&cachep->node[cpu_to_mem(i)]->list_lock);
3872 return alloc_kmemlist(cachep, gfp);
3875 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3876 int batchcount, int shared, gfp_t gfp)
3879 struct kmem_cache *c = NULL;
3882 ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3884 if (slab_state < FULL)
3887 if ((ret < 0) || !is_root_cache(cachep))
3890 VM_BUG_ON(!mutex_is_locked(&slab_mutex));
3891 for_each_memcg_cache_index(i) {
3892 c = cache_from_memcg_idx(cachep, i);
3894 /* return value determined by the parent cache only */
3895 __do_tune_cpucache(c, limit, batchcount, shared, gfp);
3901 /* Called with slab_mutex held always */
3902 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3909 if (!is_root_cache(cachep)) {
3910 struct kmem_cache *root = memcg_root_cache(cachep);
3911 limit = root->limit;
3912 shared = root->shared;
3913 batchcount = root->batchcount;
3916 if (limit && shared && batchcount)
3919 * The head array serves three purposes:
3920 * - create a LIFO ordering, i.e. return objects that are cache-warm
3921 * - reduce the number of spinlock operations.
3922 * - reduce the number of linked list operations on the slab and
3923 * bufctl chains: array operations are cheaper.
3924 * The numbers are guessed, we should auto-tune as described by
3927 if (cachep->size > 131072)
3929 else if (cachep->size > PAGE_SIZE)
3931 else if (cachep->size > 1024)
3933 else if (cachep->size > 256)
3939 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3940 * allocation behaviour: Most allocs on one cpu, most free operations
3941 * on another cpu. For these cases, an efficient object passing between
3942 * cpus is necessary. This is provided by a shared array. The array
3943 * replaces Bonwick's magazine layer.
3944 * On uniprocessor, it's functionally equivalent (but less efficient)
3945 * to a larger limit. Thus disabled by default.
3948 if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
3953 * With debugging enabled, large batchcount lead to excessively long
3954 * periods with disabled local interrupts. Limit the batchcount
3959 batchcount = (limit + 1) / 2;
3961 err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3963 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
3964 cachep->name, -err);
3969 * Drain an array if it contains any elements taking the node lock only if
3970 * necessary. Note that the node listlock also protects the array_cache
3971 * if drain_array() is used on the shared array.
3973 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
3974 struct array_cache *ac, int force, int node)
3978 if (!ac || !ac->avail)
3980 if (ac->touched && !force) {
3983 spin_lock_irq(&n->list_lock);
3985 tofree = force ? ac->avail : (ac->limit + 4) / 5;
3986 if (tofree > ac->avail)
3987 tofree = (ac->avail + 1) / 2;
3988 free_block(cachep, ac->entry, tofree, node);
3989 ac->avail -= tofree;
3990 memmove(ac->entry, &(ac->entry[tofree]),
3991 sizeof(void *) * ac->avail);
3993 spin_unlock_irq(&n->list_lock);
3998 * cache_reap - Reclaim memory from caches.
3999 * @w: work descriptor
4001 * Called from workqueue/eventd every few seconds.
4003 * - clear the per-cpu caches for this CPU.
4004 * - return freeable pages to the main free memory pool.
4006 * If we cannot acquire the cache chain mutex then just give up - we'll try
4007 * again on the next iteration.
4009 static void cache_reap(struct work_struct *w)
4011 struct kmem_cache *searchp;
4012 struct kmem_cache_node *n;
4013 int node = numa_mem_id();
4014 struct delayed_work *work = to_delayed_work(w);
4016 if (!mutex_trylock(&slab_mutex))
4017 /* Give up. Setup the next iteration. */
4020 list_for_each_entry(searchp, &slab_caches, list) {
4024 * We only take the node lock if absolutely necessary and we
4025 * have established with reasonable certainty that
4026 * we can do some work if the lock was obtained.
4028 n = searchp->node[node];
4030 reap_alien(searchp, n);
4032 drain_array(searchp, n, cpu_cache_get(searchp), 0, node);
4035 * These are racy checks but it does not matter
4036 * if we skip one check or scan twice.
4038 if (time_after(n->next_reap, jiffies))
4041 n->next_reap = jiffies + REAPTIMEOUT_LIST3;
4043 drain_array(searchp, n, n->shared, 0, node);
4045 if (n->free_touched)
4046 n->free_touched = 0;
4050 freed = drain_freelist(searchp, n, (n->free_limit +
4051 5 * searchp->num - 1) / (5 * searchp->num));
4052 STATS_ADD_REAPED(searchp, freed);
4058 mutex_unlock(&slab_mutex);
4061 /* Set up the next iteration */
4062 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
4065 #ifdef CONFIG_SLABINFO
4066 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
4069 unsigned long active_objs;
4070 unsigned long num_objs;
4071 unsigned long active_slabs = 0;
4072 unsigned long num_slabs, free_objects = 0, shared_avail = 0;
4076 struct kmem_cache_node *n;
4080 for_each_online_node(node) {
4081 n = cachep->node[node];
4086 spin_lock_irq(&n->list_lock);
4088 list_for_each_entry(page, &n->slabs_full, lru) {
4089 if (page->active != cachep->num && !error)
4090 error = "slabs_full accounting error";
4091 active_objs += cachep->num;
4094 list_for_each_entry(page, &n->slabs_partial, lru) {
4095 if (page->active == cachep->num && !error)
4096 error = "slabs_partial accounting error";
4097 if (!page->active && !error)
4098 error = "slabs_partial accounting error";
4099 active_objs += page->active;
4102 list_for_each_entry(page, &n->slabs_free, lru) {
4103 if (page->active && !error)
4104 error = "slabs_free accounting error";
4107 free_objects += n->free_objects;
4109 shared_avail += n->shared->avail;
4111 spin_unlock_irq(&n->list_lock);
4113 num_slabs += active_slabs;
4114 num_objs = num_slabs * cachep->num;
4115 if (num_objs - active_objs != free_objects && !error)
4116 error = "free_objects accounting error";
4118 name = cachep->name;
4120 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
4122 sinfo->active_objs = active_objs;
4123 sinfo->num_objs = num_objs;
4124 sinfo->active_slabs = active_slabs;
4125 sinfo->num_slabs = num_slabs;
4126 sinfo->shared_avail = shared_avail;
4127 sinfo->limit = cachep->limit;
4128 sinfo->batchcount = cachep->batchcount;
4129 sinfo->shared = cachep->shared;
4130 sinfo->objects_per_slab = cachep->num;
4131 sinfo->cache_order = cachep->gfporder;
4134 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
4138 unsigned long high = cachep->high_mark;
4139 unsigned long allocs = cachep->num_allocations;
4140 unsigned long grown = cachep->grown;
4141 unsigned long reaped = cachep->reaped;
4142 unsigned long errors = cachep->errors;
4143 unsigned long max_freeable = cachep->max_freeable;
4144 unsigned long node_allocs = cachep->node_allocs;
4145 unsigned long node_frees = cachep->node_frees;
4146 unsigned long overflows = cachep->node_overflow;
4148 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu "
4149 "%4lu %4lu %4lu %4lu %4lu",
4150 allocs, high, grown,
4151 reaped, errors, max_freeable, node_allocs,
4152 node_frees, overflows);
4156 unsigned long allochit = atomic_read(&cachep->allochit);
4157 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4158 unsigned long freehit = atomic_read(&cachep->freehit);
4159 unsigned long freemiss = atomic_read(&cachep->freemiss);
4161 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4162 allochit, allocmiss, freehit, freemiss);
4167 #define MAX_SLABINFO_WRITE 128
4169 * slabinfo_write - Tuning for the slab allocator
4171 * @buffer: user buffer
4172 * @count: data length
4175 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
4176 size_t count, loff_t *ppos)
4178 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4179 int limit, batchcount, shared, res;
4180 struct kmem_cache *cachep;
4182 if (count > MAX_SLABINFO_WRITE)
4184 if (copy_from_user(&kbuf, buffer, count))
4186 kbuf[MAX_SLABINFO_WRITE] = '\0';
4188 tmp = strchr(kbuf, ' ');
4193 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4196 /* Find the cache in the chain of caches. */
4197 mutex_lock(&slab_mutex);
4199 list_for_each_entry(cachep, &slab_caches, list) {
4200 if (!strcmp(cachep->name, kbuf)) {
4201 if (limit < 1 || batchcount < 1 ||
4202 batchcount > limit || shared < 0) {
4205 res = do_tune_cpucache(cachep, limit,
4212 mutex_unlock(&slab_mutex);
4218 #ifdef CONFIG_DEBUG_SLAB_LEAK
4220 static void *leaks_start(struct seq_file *m, loff_t *pos)
4222 mutex_lock(&slab_mutex);
4223 return seq_list_start(&slab_caches, *pos);
4226 static inline int add_caller(unsigned long *n, unsigned long v)
4236 unsigned long *q = p + 2 * i;
4250 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4256 static void handle_slab(unsigned long *n, struct kmem_cache *c,
4264 for (i = 0, p = page->s_mem; i < c->num; i++, p += c->size) {
4265 if (get_obj_status(page, i) != OBJECT_ACTIVE)
4268 if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4273 static void show_symbol(struct seq_file *m, unsigned long address)
4275 #ifdef CONFIG_KALLSYMS
4276 unsigned long offset, size;
4277 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4279 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4280 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4282 seq_printf(m, " [%s]", modname);
4286 seq_printf(m, "%p", (void *)address);
4289 static int leaks_show(struct seq_file *m, void *p)
4291 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
4293 struct kmem_cache_node *n;
4295 unsigned long *x = m->private;
4299 if (!(cachep->flags & SLAB_STORE_USER))
4301 if (!(cachep->flags & SLAB_RED_ZONE))
4304 /* OK, we can do it */
4308 for_each_online_node(node) {
4309 n = cachep->node[node];
4314 spin_lock_irq(&n->list_lock);
4316 list_for_each_entry(page, &n->slabs_full, lru)
4317 handle_slab(x, cachep, page);
4318 list_for_each_entry(page, &n->slabs_partial, lru)
4319 handle_slab(x, cachep, page);
4320 spin_unlock_irq(&n->list_lock);
4322 name = cachep->name;
4324 /* Increase the buffer size */
4325 mutex_unlock(&slab_mutex);
4326 m->private = kzalloc(x[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4328 /* Too bad, we are really out */
4330 mutex_lock(&slab_mutex);
4333 *(unsigned long *)m->private = x[0] * 2;
4335 mutex_lock(&slab_mutex);
4336 /* Now make sure this entry will be retried */
4340 for (i = 0; i < x[1]; i++) {
4341 seq_printf(m, "%s: %lu ", name, x[2*i+3]);
4342 show_symbol(m, x[2*i+2]);
4349 static const struct seq_operations slabstats_op = {
4350 .start = leaks_start,
4356 static int slabstats_open(struct inode *inode, struct file *file)
4358 unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL);
4361 ret = seq_open(file, &slabstats_op);
4363 struct seq_file *m = file->private_data;
4364 *n = PAGE_SIZE / (2 * sizeof(unsigned long));
4373 static const struct file_operations proc_slabstats_operations = {
4374 .open = slabstats_open,
4376 .llseek = seq_lseek,
4377 .release = seq_release_private,
4381 static int __init slab_proc_init(void)
4383 #ifdef CONFIG_DEBUG_SLAB_LEAK
4384 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4388 module_init(slab_proc_init);
4392 * ksize - get the actual amount of memory allocated for a given object
4393 * @objp: Pointer to the object
4395 * kmalloc may internally round up allocations and return more memory
4396 * than requested. ksize() can be used to determine the actual amount of
4397 * memory allocated. The caller may use this additional memory, even though
4398 * a smaller amount of memory was initially specified with the kmalloc call.
4399 * The caller must guarantee that objp points to a valid object previously
4400 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4401 * must not be freed during the duration of the call.
4403 size_t ksize(const void *objp)
4406 if (unlikely(objp == ZERO_SIZE_PTR))
4409 return virt_to_cache(objp)->object_size;
4411 EXPORT_SYMBOL(ksize);