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;
169 * Bufctl's are used for linking objs within a slab
172 * This implementation relies on "struct page" for locating the cache &
173 * slab an object belongs to.
174 * This allows the bufctl structure to be small (one int), but limits
175 * the number of objects a slab (not a cache) can contain when off-slab
176 * bufctls are used. The limit is the size of the largest general cache
177 * that does not use off-slab slabs.
178 * For 32bit archs with 4 kB pages, is this 56.
179 * This is not serious, as it is only for large objects, when it is unwise
180 * to have too many per slab.
181 * Note: This limit can be raised by introducing a general cache whose size
182 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
185 typedef unsigned int kmem_bufctl_t;
186 #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
187 #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
188 #define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2)
189 #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3)
194 * Manages the objs in a slab. Placed either at the beginning of mem allocated
195 * for a slab, or allocated from an general cache.
196 * Slabs are chained into three list: fully used, partial, fully free slabs.
200 struct list_head list;
201 void *s_mem; /* including colour offset */
202 unsigned int inuse; /* num of objs active in slab */
211 * - LIFO ordering, to hand out cache-warm objects from _alloc
212 * - reduce the number of linked list operations
213 * - reduce spinlock operations
215 * The limit is stored in the per-cpu structure to reduce the data cache
222 unsigned int batchcount;
223 unsigned int touched;
226 * Must have this definition in here for the proper
227 * alignment of array_cache. Also simplifies accessing
230 * Entries should not be directly dereferenced as
231 * entries belonging to slabs marked pfmemalloc will
232 * have the lower bits set SLAB_OBJ_PFMEMALLOC
236 #define SLAB_OBJ_PFMEMALLOC 1
237 static inline bool is_obj_pfmemalloc(void *objp)
239 return (unsigned long)objp & SLAB_OBJ_PFMEMALLOC;
242 static inline void set_obj_pfmemalloc(void **objp)
244 *objp = (void *)((unsigned long)*objp | SLAB_OBJ_PFMEMALLOC);
248 static inline void clear_obj_pfmemalloc(void **objp)
250 *objp = (void *)((unsigned long)*objp & ~SLAB_OBJ_PFMEMALLOC);
254 * bootstrap: The caches do not work without cpuarrays anymore, but the
255 * cpuarrays are allocated from the generic caches...
257 #define BOOT_CPUCACHE_ENTRIES 1
258 struct arraycache_init {
259 struct array_cache cache;
260 void *entries[BOOT_CPUCACHE_ENTRIES];
264 * Need this for bootstrapping a per node allocator.
266 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
267 static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS];
268 #define CACHE_CACHE 0
269 #define SIZE_AC MAX_NUMNODES
270 #define SIZE_NODE (2 * MAX_NUMNODES)
272 static int drain_freelist(struct kmem_cache *cache,
273 struct kmem_cache_node *n, int tofree);
274 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
276 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
277 static void cache_reap(struct work_struct *unused);
279 static int slab_early_init = 1;
281 #define INDEX_AC kmalloc_index(sizeof(struct arraycache_init))
282 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
284 static void kmem_cache_node_init(struct kmem_cache_node *parent)
286 INIT_LIST_HEAD(&parent->slabs_full);
287 INIT_LIST_HEAD(&parent->slabs_partial);
288 INIT_LIST_HEAD(&parent->slabs_free);
289 parent->shared = NULL;
290 parent->alien = NULL;
291 parent->colour_next = 0;
292 spin_lock_init(&parent->list_lock);
293 parent->free_objects = 0;
294 parent->free_touched = 0;
297 #define MAKE_LIST(cachep, listp, slab, nodeid) \
299 INIT_LIST_HEAD(listp); \
300 list_splice(&(cachep->node[nodeid]->slab), listp); \
303 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
305 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
306 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
307 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
310 #define CFLGS_OFF_SLAB (0x80000000UL)
311 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
313 #define BATCHREFILL_LIMIT 16
315 * Optimization question: fewer reaps means less probability for unnessary
316 * cpucache drain/refill cycles.
318 * OTOH the cpuarrays can contain lots of objects,
319 * which could lock up otherwise freeable slabs.
321 #define REAPTIMEOUT_CPUC (2*HZ)
322 #define REAPTIMEOUT_LIST3 (4*HZ)
325 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
326 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
327 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
328 #define STATS_INC_GROWN(x) ((x)->grown++)
329 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
330 #define STATS_SET_HIGH(x) \
332 if ((x)->num_active > (x)->high_mark) \
333 (x)->high_mark = (x)->num_active; \
335 #define STATS_INC_ERR(x) ((x)->errors++)
336 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
337 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
338 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
339 #define STATS_SET_FREEABLE(x, i) \
341 if ((x)->max_freeable < i) \
342 (x)->max_freeable = i; \
344 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
345 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
346 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
347 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
349 #define STATS_INC_ACTIVE(x) do { } while (0)
350 #define STATS_DEC_ACTIVE(x) do { } while (0)
351 #define STATS_INC_ALLOCED(x) do { } while (0)
352 #define STATS_INC_GROWN(x) do { } while (0)
353 #define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0)
354 #define STATS_SET_HIGH(x) do { } while (0)
355 #define STATS_INC_ERR(x) do { } while (0)
356 #define STATS_INC_NODEALLOCS(x) do { } while (0)
357 #define STATS_INC_NODEFREES(x) do { } while (0)
358 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
359 #define STATS_SET_FREEABLE(x, i) do { } while (0)
360 #define STATS_INC_ALLOCHIT(x) do { } while (0)
361 #define STATS_INC_ALLOCMISS(x) do { } while (0)
362 #define STATS_INC_FREEHIT(x) do { } while (0)
363 #define STATS_INC_FREEMISS(x) do { } while (0)
369 * memory layout of objects:
371 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
372 * the end of an object is aligned with the end of the real
373 * allocation. Catches writes behind the end of the allocation.
374 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
376 * cachep->obj_offset: The real object.
377 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
378 * cachep->size - 1* BYTES_PER_WORD: last caller address
379 * [BYTES_PER_WORD long]
381 static int obj_offset(struct kmem_cache *cachep)
383 return cachep->obj_offset;
386 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
388 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
389 return (unsigned long long*) (objp + obj_offset(cachep) -
390 sizeof(unsigned long long));
393 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
395 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
396 if (cachep->flags & SLAB_STORE_USER)
397 return (unsigned long long *)(objp + cachep->size -
398 sizeof(unsigned long long) -
400 return (unsigned long long *) (objp + cachep->size -
401 sizeof(unsigned long long));
404 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
406 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
407 return (void **)(objp + cachep->size - BYTES_PER_WORD);
412 #define obj_offset(x) 0
413 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
414 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
415 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
420 * Do not go above this order unless 0 objects fit into the slab or
421 * overridden on the command line.
423 #define SLAB_MAX_ORDER_HI 1
424 #define SLAB_MAX_ORDER_LO 0
425 static int slab_max_order = SLAB_MAX_ORDER_LO;
426 static bool slab_max_order_set __initdata;
428 static inline struct kmem_cache *virt_to_cache(const void *obj)
430 struct page *page = virt_to_head_page(obj);
431 return page->slab_cache;
434 static inline struct slab *virt_to_slab(const void *obj)
436 struct page *page = virt_to_head_page(obj);
438 VM_BUG_ON(!PageSlab(page));
439 return page->slab_page;
442 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
445 return slab->s_mem + cache->size * idx;
449 * We want to avoid an expensive divide : (offset / cache->size)
450 * Using the fact that size is a constant for a particular cache,
451 * we can replace (offset / cache->size) by
452 * reciprocal_divide(offset, cache->reciprocal_buffer_size)
454 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
455 const struct slab *slab, void *obj)
457 u32 offset = (obj - slab->s_mem);
458 return reciprocal_divide(offset, cache->reciprocal_buffer_size);
461 static struct arraycache_init initarray_generic =
462 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
464 /* internal cache of cache description objs */
465 static struct kmem_cache kmem_cache_boot = {
467 .limit = BOOT_CPUCACHE_ENTRIES,
469 .size = sizeof(struct kmem_cache),
470 .name = "kmem_cache",
473 #define BAD_ALIEN_MAGIC 0x01020304ul
475 #ifdef CONFIG_LOCKDEP
478 * Slab sometimes uses the kmalloc slabs to store the slab headers
479 * for other slabs "off slab".
480 * The locking for this is tricky in that it nests within the locks
481 * of all other slabs in a few places; to deal with this special
482 * locking we put on-slab caches into a separate lock-class.
484 * We set lock class for alien array caches which are up during init.
485 * The lock annotation will be lost if all cpus of a node goes down and
486 * then comes back up during hotplug
488 static struct lock_class_key on_slab_l3_key;
489 static struct lock_class_key on_slab_alc_key;
491 static struct lock_class_key debugobj_l3_key;
492 static struct lock_class_key debugobj_alc_key;
494 static void slab_set_lock_classes(struct kmem_cache *cachep,
495 struct lock_class_key *l3_key, struct lock_class_key *alc_key,
498 struct array_cache **alc;
499 struct kmem_cache_node *n;
506 lockdep_set_class(&n->list_lock, l3_key);
509 * FIXME: This check for BAD_ALIEN_MAGIC
510 * should go away when common slab code is taught to
511 * work even without alien caches.
512 * Currently, non NUMA code returns BAD_ALIEN_MAGIC
513 * for alloc_alien_cache,
515 if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
519 lockdep_set_class(&alc[r]->lock, alc_key);
523 static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
525 slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node);
528 static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
532 for_each_online_node(node)
533 slab_set_debugobj_lock_classes_node(cachep, node);
536 static void init_node_lock_keys(int q)
543 for (i = 1; i <= KMALLOC_SHIFT_HIGH; i++) {
544 struct kmem_cache_node *n;
545 struct kmem_cache *cache = kmalloc_caches[i];
551 if (!n || OFF_SLAB(cache))
554 slab_set_lock_classes(cache, &on_slab_l3_key,
555 &on_slab_alc_key, q);
559 static void on_slab_lock_classes_node(struct kmem_cache *cachep, int q)
561 if (!cachep->node[q])
564 slab_set_lock_classes(cachep, &on_slab_l3_key,
565 &on_slab_alc_key, q);
568 static inline void on_slab_lock_classes(struct kmem_cache *cachep)
572 VM_BUG_ON(OFF_SLAB(cachep));
574 on_slab_lock_classes_node(cachep, node);
577 static inline void init_lock_keys(void)
582 init_node_lock_keys(node);
585 static void init_node_lock_keys(int q)
589 static inline void init_lock_keys(void)
593 static inline void on_slab_lock_classes(struct kmem_cache *cachep)
597 static inline void on_slab_lock_classes_node(struct kmem_cache *cachep, int node)
601 static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
605 static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
610 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
612 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
614 return cachep->array[smp_processor_id()];
617 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
619 return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
623 * Calculate the number of objects and left-over bytes for a given buffer size.
625 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
626 size_t align, int flags, size_t *left_over,
631 size_t slab_size = PAGE_SIZE << gfporder;
634 * The slab management structure can be either off the slab or
635 * on it. For the latter case, the memory allocated for a
639 * - One kmem_bufctl_t for each object
640 * - Padding to respect alignment of @align
641 * - @buffer_size bytes for each object
643 * If the slab management structure is off the slab, then the
644 * alignment will already be calculated into the size. Because
645 * the slabs are all pages aligned, the objects will be at the
646 * correct alignment when allocated.
648 if (flags & CFLGS_OFF_SLAB) {
650 nr_objs = slab_size / buffer_size;
652 if (nr_objs > SLAB_LIMIT)
653 nr_objs = SLAB_LIMIT;
656 * Ignore padding for the initial guess. The padding
657 * is at most @align-1 bytes, and @buffer_size is at
658 * least @align. In the worst case, this result will
659 * be one greater than the number of objects that fit
660 * into the memory allocation when taking the padding
663 nr_objs = (slab_size - sizeof(struct slab)) /
664 (buffer_size + sizeof(kmem_bufctl_t));
667 * This calculated number will be either the right
668 * amount, or one greater than what we want.
670 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
674 if (nr_objs > SLAB_LIMIT)
675 nr_objs = SLAB_LIMIT;
677 mgmt_size = slab_mgmt_size(nr_objs, align);
680 *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
684 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
686 static void __slab_error(const char *function, struct kmem_cache *cachep,
689 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
690 function, cachep->name, msg);
692 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
697 * By default on NUMA we use alien caches to stage the freeing of
698 * objects allocated from other nodes. This causes massive memory
699 * inefficiencies when using fake NUMA setup to split memory into a
700 * large number of small nodes, so it can be disabled on the command
704 static int use_alien_caches __read_mostly = 1;
705 static int __init noaliencache_setup(char *s)
707 use_alien_caches = 0;
710 __setup("noaliencache", noaliencache_setup);
712 static int __init slab_max_order_setup(char *str)
714 get_option(&str, &slab_max_order);
715 slab_max_order = slab_max_order < 0 ? 0 :
716 min(slab_max_order, MAX_ORDER - 1);
717 slab_max_order_set = true;
721 __setup("slab_max_order=", slab_max_order_setup);
725 * Special reaping functions for NUMA systems called from cache_reap().
726 * These take care of doing round robin flushing of alien caches (containing
727 * objects freed on different nodes from which they were allocated) and the
728 * flushing of remote pcps by calling drain_node_pages.
730 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
732 static void init_reap_node(int cpu)
736 node = next_node(cpu_to_mem(cpu), node_online_map);
737 if (node == MAX_NUMNODES)
738 node = first_node(node_online_map);
740 per_cpu(slab_reap_node, cpu) = node;
743 static void next_reap_node(void)
745 int node = __this_cpu_read(slab_reap_node);
747 node = next_node(node, node_online_map);
748 if (unlikely(node >= MAX_NUMNODES))
749 node = first_node(node_online_map);
750 __this_cpu_write(slab_reap_node, node);
754 #define init_reap_node(cpu) do { } while (0)
755 #define next_reap_node(void) do { } while (0)
759 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
760 * via the workqueue/eventd.
761 * Add the CPU number into the expiration time to minimize the possibility of
762 * the CPUs getting into lockstep and contending for the global cache chain
765 static void start_cpu_timer(int cpu)
767 struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
770 * When this gets called from do_initcalls via cpucache_init(),
771 * init_workqueues() has already run, so keventd will be setup
774 if (keventd_up() && reap_work->work.func == NULL) {
776 INIT_DEFERRABLE_WORK(reap_work, cache_reap);
777 schedule_delayed_work_on(cpu, reap_work,
778 __round_jiffies_relative(HZ, cpu));
782 static struct array_cache *alloc_arraycache(int node, int entries,
783 int batchcount, gfp_t gfp)
785 int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
786 struct array_cache *nc = NULL;
788 nc = kmalloc_node(memsize, gfp, node);
790 * The array_cache structures contain pointers to free object.
791 * However, when such objects are allocated or transferred to another
792 * cache the pointers are not cleared and they could be counted as
793 * valid references during a kmemleak scan. Therefore, kmemleak must
794 * not scan such objects.
796 kmemleak_no_scan(nc);
800 nc->batchcount = batchcount;
802 spin_lock_init(&nc->lock);
807 static inline bool is_slab_pfmemalloc(struct slab *slabp)
809 struct page *page = virt_to_page(slabp->s_mem);
811 return PageSlabPfmemalloc(page);
814 /* Clears pfmemalloc_active if no slabs have pfmalloc set */
815 static void recheck_pfmemalloc_active(struct kmem_cache *cachep,
816 struct array_cache *ac)
818 struct kmem_cache_node *n = cachep->node[numa_mem_id()];
822 if (!pfmemalloc_active)
825 spin_lock_irqsave(&n->list_lock, flags);
826 list_for_each_entry(slabp, &n->slabs_full, list)
827 if (is_slab_pfmemalloc(slabp))
830 list_for_each_entry(slabp, &n->slabs_partial, list)
831 if (is_slab_pfmemalloc(slabp))
834 list_for_each_entry(slabp, &n->slabs_free, list)
835 if (is_slab_pfmemalloc(slabp))
838 pfmemalloc_active = false;
840 spin_unlock_irqrestore(&n->list_lock, flags);
843 static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
844 gfp_t flags, bool force_refill)
847 void *objp = ac->entry[--ac->avail];
849 /* Ensure the caller is allowed to use objects from PFMEMALLOC slab */
850 if (unlikely(is_obj_pfmemalloc(objp))) {
851 struct kmem_cache_node *n;
853 if (gfp_pfmemalloc_allowed(flags)) {
854 clear_obj_pfmemalloc(&objp);
858 /* The caller cannot use PFMEMALLOC objects, find another one */
859 for (i = 0; i < ac->avail; i++) {
860 /* If a !PFMEMALLOC object is found, swap them */
861 if (!is_obj_pfmemalloc(ac->entry[i])) {
863 ac->entry[i] = ac->entry[ac->avail];
864 ac->entry[ac->avail] = objp;
870 * If there are empty slabs on the slabs_free list and we are
871 * being forced to refill the cache, mark this one !pfmemalloc.
873 n = cachep->node[numa_mem_id()];
874 if (!list_empty(&n->slabs_free) && force_refill) {
875 struct slab *slabp = virt_to_slab(objp);
876 ClearPageSlabPfmemalloc(virt_to_head_page(slabp->s_mem));
877 clear_obj_pfmemalloc(&objp);
878 recheck_pfmemalloc_active(cachep, ac);
882 /* No !PFMEMALLOC objects available */
890 static inline void *ac_get_obj(struct kmem_cache *cachep,
891 struct array_cache *ac, gfp_t flags, bool force_refill)
895 if (unlikely(sk_memalloc_socks()))
896 objp = __ac_get_obj(cachep, ac, flags, force_refill);
898 objp = ac->entry[--ac->avail];
903 static void *__ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
906 if (unlikely(pfmemalloc_active)) {
907 /* Some pfmemalloc slabs exist, check if this is one */
908 struct slab *slabp = virt_to_slab(objp);
909 struct page *page = virt_to_head_page(slabp->s_mem);
910 if (PageSlabPfmemalloc(page))
911 set_obj_pfmemalloc(&objp);
917 static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
920 if (unlikely(sk_memalloc_socks()))
921 objp = __ac_put_obj(cachep, ac, objp);
923 ac->entry[ac->avail++] = objp;
927 * Transfer objects in one arraycache to another.
928 * Locking must be handled by the caller.
930 * Return the number of entries transferred.
932 static int transfer_objects(struct array_cache *to,
933 struct array_cache *from, unsigned int max)
935 /* Figure out how many entries to transfer */
936 int nr = min3(from->avail, max, to->limit - to->avail);
941 memcpy(to->entry + to->avail, from->entry + from->avail -nr,
951 #define drain_alien_cache(cachep, alien) do { } while (0)
952 #define reap_alien(cachep, n) do { } while (0)
954 static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
956 return (struct array_cache **)BAD_ALIEN_MAGIC;
959 static inline void free_alien_cache(struct array_cache **ac_ptr)
963 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
968 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
974 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
975 gfp_t flags, int nodeid)
980 #else /* CONFIG_NUMA */
982 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
983 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
985 static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
987 struct array_cache **ac_ptr;
988 int memsize = sizeof(void *) * nr_node_ids;
993 ac_ptr = kzalloc_node(memsize, gfp, node);
996 if (i == node || !node_online(i))
998 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
1000 for (i--; i >= 0; i--)
1010 static void free_alien_cache(struct array_cache **ac_ptr)
1021 static void __drain_alien_cache(struct kmem_cache *cachep,
1022 struct array_cache *ac, int node)
1024 struct kmem_cache_node *n = cachep->node[node];
1027 spin_lock(&n->list_lock);
1029 * Stuff objects into the remote nodes shared array first.
1030 * That way we could avoid the overhead of putting the objects
1031 * into the free lists and getting them back later.
1034 transfer_objects(n->shared, ac, ac->limit);
1036 free_block(cachep, ac->entry, ac->avail, node);
1038 spin_unlock(&n->list_lock);
1043 * Called from cache_reap() to regularly drain alien caches round robin.
1045 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
1047 int node = __this_cpu_read(slab_reap_node);
1050 struct array_cache *ac = n->alien[node];
1052 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1053 __drain_alien_cache(cachep, ac, node);
1054 spin_unlock_irq(&ac->lock);
1059 static void drain_alien_cache(struct kmem_cache *cachep,
1060 struct array_cache **alien)
1063 struct array_cache *ac;
1064 unsigned long flags;
1066 for_each_online_node(i) {
1069 spin_lock_irqsave(&ac->lock, flags);
1070 __drain_alien_cache(cachep, ac, i);
1071 spin_unlock_irqrestore(&ac->lock, flags);
1076 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1078 int nodeid = page_to_nid(virt_to_page(objp));
1079 struct kmem_cache_node *n;
1080 struct array_cache *alien = NULL;
1083 node = numa_mem_id();
1086 * Make sure we are not freeing a object from another node to the array
1087 * cache on this cpu.
1089 if (likely(nodeid == node))
1092 n = cachep->node[node];
1093 STATS_INC_NODEFREES(cachep);
1094 if (n->alien && n->alien[nodeid]) {
1095 alien = n->alien[nodeid];
1096 spin_lock(&alien->lock);
1097 if (unlikely(alien->avail == alien->limit)) {
1098 STATS_INC_ACOVERFLOW(cachep);
1099 __drain_alien_cache(cachep, alien, nodeid);
1101 ac_put_obj(cachep, alien, objp);
1102 spin_unlock(&alien->lock);
1104 spin_lock(&(cachep->node[nodeid])->list_lock);
1105 free_block(cachep, &objp, 1, nodeid);
1106 spin_unlock(&(cachep->node[nodeid])->list_lock);
1113 * Allocates and initializes node for a node on each slab cache, used for
1114 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node
1115 * will be allocated off-node since memory is not yet online for the new node.
1116 * When hotplugging memory or a cpu, existing node are not replaced if
1119 * Must hold slab_mutex.
1121 static int init_cache_node_node(int node)
1123 struct kmem_cache *cachep;
1124 struct kmem_cache_node *n;
1125 const int memsize = sizeof(struct kmem_cache_node);
1127 list_for_each_entry(cachep, &slab_caches, list) {
1129 * Set up the size64 kmemlist for cpu before we can
1130 * begin anything. Make sure some other cpu on this
1131 * node has not already allocated this
1133 if (!cachep->node[node]) {
1134 n = kmalloc_node(memsize, GFP_KERNEL, node);
1137 kmem_cache_node_init(n);
1138 n->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1139 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1142 * The l3s don't come and go as CPUs come and
1143 * go. slab_mutex is sufficient
1146 cachep->node[node] = n;
1149 spin_lock_irq(&cachep->node[node]->list_lock);
1150 cachep->node[node]->free_limit =
1151 (1 + nr_cpus_node(node)) *
1152 cachep->batchcount + cachep->num;
1153 spin_unlock_irq(&cachep->node[node]->list_lock);
1158 static inline int slabs_tofree(struct kmem_cache *cachep,
1159 struct kmem_cache_node *n)
1161 return (n->free_objects + cachep->num - 1) / cachep->num;
1164 static void cpuup_canceled(long cpu)
1166 struct kmem_cache *cachep;
1167 struct kmem_cache_node *n = NULL;
1168 int node = cpu_to_mem(cpu);
1169 const struct cpumask *mask = cpumask_of_node(node);
1171 list_for_each_entry(cachep, &slab_caches, list) {
1172 struct array_cache *nc;
1173 struct array_cache *shared;
1174 struct array_cache **alien;
1176 /* cpu is dead; no one can alloc from it. */
1177 nc = cachep->array[cpu];
1178 cachep->array[cpu] = NULL;
1179 n = cachep->node[node];
1182 goto free_array_cache;
1184 spin_lock_irq(&n->list_lock);
1186 /* Free limit for this kmem_cache_node */
1187 n->free_limit -= cachep->batchcount;
1189 free_block(cachep, nc->entry, nc->avail, node);
1191 if (!cpumask_empty(mask)) {
1192 spin_unlock_irq(&n->list_lock);
1193 goto free_array_cache;
1198 free_block(cachep, shared->entry,
1199 shared->avail, node);
1206 spin_unlock_irq(&n->list_lock);
1210 drain_alien_cache(cachep, alien);
1211 free_alien_cache(alien);
1217 * In the previous loop, all the objects were freed to
1218 * the respective cache's slabs, now we can go ahead and
1219 * shrink each nodelist to its limit.
1221 list_for_each_entry(cachep, &slab_caches, list) {
1222 n = cachep->node[node];
1225 drain_freelist(cachep, n, slabs_tofree(cachep, n));
1229 static int cpuup_prepare(long cpu)
1231 struct kmem_cache *cachep;
1232 struct kmem_cache_node *n = NULL;
1233 int node = cpu_to_mem(cpu);
1237 * We need to do this right in the beginning since
1238 * alloc_arraycache's are going to use this list.
1239 * kmalloc_node allows us to add the slab to the right
1240 * kmem_cache_node and not this cpu's kmem_cache_node
1242 err = init_cache_node_node(node);
1247 * Now we can go ahead with allocating the shared arrays and
1250 list_for_each_entry(cachep, &slab_caches, list) {
1251 struct array_cache *nc;
1252 struct array_cache *shared = NULL;
1253 struct array_cache **alien = NULL;
1255 nc = alloc_arraycache(node, cachep->limit,
1256 cachep->batchcount, GFP_KERNEL);
1259 if (cachep->shared) {
1260 shared = alloc_arraycache(node,
1261 cachep->shared * cachep->batchcount,
1262 0xbaadf00d, GFP_KERNEL);
1268 if (use_alien_caches) {
1269 alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
1276 cachep->array[cpu] = nc;
1277 n = cachep->node[node];
1280 spin_lock_irq(&n->list_lock);
1283 * We are serialised from CPU_DEAD or
1284 * CPU_UP_CANCELLED by the cpucontrol lock
1295 spin_unlock_irq(&n->list_lock);
1297 free_alien_cache(alien);
1298 if (cachep->flags & SLAB_DEBUG_OBJECTS)
1299 slab_set_debugobj_lock_classes_node(cachep, node);
1300 else if (!OFF_SLAB(cachep) &&
1301 !(cachep->flags & SLAB_DESTROY_BY_RCU))
1302 on_slab_lock_classes_node(cachep, node);
1304 init_node_lock_keys(node);
1308 cpuup_canceled(cpu);
1312 static int cpuup_callback(struct notifier_block *nfb,
1313 unsigned long action, void *hcpu)
1315 long cpu = (long)hcpu;
1319 case CPU_UP_PREPARE:
1320 case CPU_UP_PREPARE_FROZEN:
1321 mutex_lock(&slab_mutex);
1322 err = cpuup_prepare(cpu);
1323 mutex_unlock(&slab_mutex);
1326 case CPU_ONLINE_FROZEN:
1327 start_cpu_timer(cpu);
1329 #ifdef CONFIG_HOTPLUG_CPU
1330 case CPU_DOWN_PREPARE:
1331 case CPU_DOWN_PREPARE_FROZEN:
1333 * Shutdown cache reaper. Note that the slab_mutex is
1334 * held so that if cache_reap() is invoked it cannot do
1335 * anything expensive but will only modify reap_work
1336 * and reschedule the timer.
1338 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
1339 /* Now the cache_reaper is guaranteed to be not running. */
1340 per_cpu(slab_reap_work, cpu).work.func = NULL;
1342 case CPU_DOWN_FAILED:
1343 case CPU_DOWN_FAILED_FROZEN:
1344 start_cpu_timer(cpu);
1347 case CPU_DEAD_FROZEN:
1349 * Even if all the cpus of a node are down, we don't free the
1350 * kmem_cache_node of any cache. This to avoid a race between
1351 * cpu_down, and a kmalloc allocation from another cpu for
1352 * memory from the node of the cpu going down. The node
1353 * structure is usually allocated from kmem_cache_create() and
1354 * gets destroyed at kmem_cache_destroy().
1358 case CPU_UP_CANCELED:
1359 case CPU_UP_CANCELED_FROZEN:
1360 mutex_lock(&slab_mutex);
1361 cpuup_canceled(cpu);
1362 mutex_unlock(&slab_mutex);
1365 return notifier_from_errno(err);
1368 static struct notifier_block cpucache_notifier = {
1369 &cpuup_callback, NULL, 0
1372 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1374 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1375 * Returns -EBUSY if all objects cannot be drained so that the node is not
1378 * Must hold slab_mutex.
1380 static int __meminit drain_cache_node_node(int node)
1382 struct kmem_cache *cachep;
1385 list_for_each_entry(cachep, &slab_caches, list) {
1386 struct kmem_cache_node *n;
1388 n = cachep->node[node];
1392 drain_freelist(cachep, n, slabs_tofree(cachep, n));
1394 if (!list_empty(&n->slabs_full) ||
1395 !list_empty(&n->slabs_partial)) {
1403 static int __meminit slab_memory_callback(struct notifier_block *self,
1404 unsigned long action, void *arg)
1406 struct memory_notify *mnb = arg;
1410 nid = mnb->status_change_nid;
1415 case MEM_GOING_ONLINE:
1416 mutex_lock(&slab_mutex);
1417 ret = init_cache_node_node(nid);
1418 mutex_unlock(&slab_mutex);
1420 case MEM_GOING_OFFLINE:
1421 mutex_lock(&slab_mutex);
1422 ret = drain_cache_node_node(nid);
1423 mutex_unlock(&slab_mutex);
1427 case MEM_CANCEL_ONLINE:
1428 case MEM_CANCEL_OFFLINE:
1432 return notifier_from_errno(ret);
1434 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1437 * swap the static kmem_cache_node with kmalloced memory
1439 static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list,
1442 struct kmem_cache_node *ptr;
1444 ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid);
1447 memcpy(ptr, list, sizeof(struct kmem_cache_node));
1449 * Do not assume that spinlocks can be initialized via memcpy:
1451 spin_lock_init(&ptr->list_lock);
1453 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1454 cachep->node[nodeid] = ptr;
1458 * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1459 * size of kmem_cache_node.
1461 static void __init set_up_node(struct kmem_cache *cachep, int index)
1465 for_each_online_node(node) {
1466 cachep->node[node] = &init_kmem_cache_node[index + node];
1467 cachep->node[node]->next_reap = jiffies +
1469 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1474 * The memory after the last cpu cache pointer is used for the
1477 static void setup_node_pointer(struct kmem_cache *cachep)
1479 cachep->node = (struct kmem_cache_node **)&cachep->array[nr_cpu_ids];
1483 * Initialisation. Called after the page allocator have been initialised and
1484 * before smp_init().
1486 void __init kmem_cache_init(void)
1490 BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) <
1491 sizeof(struct rcu_head));
1492 kmem_cache = &kmem_cache_boot;
1493 setup_node_pointer(kmem_cache);
1495 if (num_possible_nodes() == 1)
1496 use_alien_caches = 0;
1498 for (i = 0; i < NUM_INIT_LISTS; i++)
1499 kmem_cache_node_init(&init_kmem_cache_node[i]);
1501 set_up_node(kmem_cache, CACHE_CACHE);
1504 * Fragmentation resistance on low memory - only use bigger
1505 * page orders on machines with more than 32MB of memory if
1506 * not overridden on the command line.
1508 if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
1509 slab_max_order = SLAB_MAX_ORDER_HI;
1511 /* Bootstrap is tricky, because several objects are allocated
1512 * from caches that do not exist yet:
1513 * 1) initialize the kmem_cache cache: it contains the struct
1514 * kmem_cache structures of all caches, except kmem_cache itself:
1515 * kmem_cache is statically allocated.
1516 * Initially an __init data area is used for the head array and the
1517 * kmem_cache_node structures, it's replaced with a kmalloc allocated
1518 * array at the end of the bootstrap.
1519 * 2) Create the first kmalloc cache.
1520 * The struct kmem_cache for the new cache is allocated normally.
1521 * An __init data area is used for the head array.
1522 * 3) Create the remaining kmalloc caches, with minimally sized
1524 * 4) Replace the __init data head arrays for kmem_cache and the first
1525 * kmalloc cache with kmalloc allocated arrays.
1526 * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1527 * the other cache's with kmalloc allocated memory.
1528 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1531 /* 1) create the kmem_cache */
1534 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1536 create_boot_cache(kmem_cache, "kmem_cache",
1537 offsetof(struct kmem_cache, array[nr_cpu_ids]) +
1538 nr_node_ids * sizeof(struct kmem_cache_node *),
1539 SLAB_HWCACHE_ALIGN);
1540 list_add(&kmem_cache->list, &slab_caches);
1542 /* 2+3) create the kmalloc caches */
1545 * Initialize the caches that provide memory for the array cache and the
1546 * kmem_cache_node structures first. Without this, further allocations will
1550 kmalloc_caches[INDEX_AC] = create_kmalloc_cache("kmalloc-ac",
1551 kmalloc_size(INDEX_AC), ARCH_KMALLOC_FLAGS);
1553 if (INDEX_AC != INDEX_NODE)
1554 kmalloc_caches[INDEX_NODE] =
1555 create_kmalloc_cache("kmalloc-node",
1556 kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS);
1558 slab_early_init = 0;
1560 /* 4) Replace the bootstrap head arrays */
1562 struct array_cache *ptr;
1564 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1566 memcpy(ptr, cpu_cache_get(kmem_cache),
1567 sizeof(struct arraycache_init));
1569 * Do not assume that spinlocks can be initialized via memcpy:
1571 spin_lock_init(&ptr->lock);
1573 kmem_cache->array[smp_processor_id()] = ptr;
1575 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1577 BUG_ON(cpu_cache_get(kmalloc_caches[INDEX_AC])
1578 != &initarray_generic.cache);
1579 memcpy(ptr, cpu_cache_get(kmalloc_caches[INDEX_AC]),
1580 sizeof(struct arraycache_init));
1582 * Do not assume that spinlocks can be initialized via memcpy:
1584 spin_lock_init(&ptr->lock);
1586 kmalloc_caches[INDEX_AC]->array[smp_processor_id()] = ptr;
1588 /* 5) Replace the bootstrap kmem_cache_node */
1592 for_each_online_node(nid) {
1593 init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid);
1595 init_list(kmalloc_caches[INDEX_AC],
1596 &init_kmem_cache_node[SIZE_AC + nid], nid);
1598 if (INDEX_AC != INDEX_NODE) {
1599 init_list(kmalloc_caches[INDEX_NODE],
1600 &init_kmem_cache_node[SIZE_NODE + nid], nid);
1605 create_kmalloc_caches(ARCH_KMALLOC_FLAGS);
1608 void __init kmem_cache_init_late(void)
1610 struct kmem_cache *cachep;
1614 /* 6) resize the head arrays to their final sizes */
1615 mutex_lock(&slab_mutex);
1616 list_for_each_entry(cachep, &slab_caches, list)
1617 if (enable_cpucache(cachep, GFP_NOWAIT))
1619 mutex_unlock(&slab_mutex);
1621 /* Annotate slab for lockdep -- annotate the malloc caches */
1628 * Register a cpu startup notifier callback that initializes
1629 * cpu_cache_get for all new cpus
1631 register_cpu_notifier(&cpucache_notifier);
1635 * Register a memory hotplug callback that initializes and frees
1638 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
1642 * The reap timers are started later, with a module init call: That part
1643 * of the kernel is not yet operational.
1647 static int __init cpucache_init(void)
1652 * Register the timers that return unneeded pages to the page allocator
1654 for_each_online_cpu(cpu)
1655 start_cpu_timer(cpu);
1661 __initcall(cpucache_init);
1663 static noinline void
1664 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
1666 struct kmem_cache_node *n;
1668 unsigned long flags;
1672 "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1674 printk(KERN_WARNING " cache: %s, object size: %d, order: %d\n",
1675 cachep->name, cachep->size, cachep->gfporder);
1677 for_each_online_node(node) {
1678 unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
1679 unsigned long active_slabs = 0, num_slabs = 0;
1681 n = cachep->node[node];
1685 spin_lock_irqsave(&n->list_lock, flags);
1686 list_for_each_entry(slabp, &n->slabs_full, list) {
1687 active_objs += cachep->num;
1690 list_for_each_entry(slabp, &n->slabs_partial, list) {
1691 active_objs += slabp->inuse;
1694 list_for_each_entry(slabp, &n->slabs_free, list)
1697 free_objects += n->free_objects;
1698 spin_unlock_irqrestore(&n->list_lock, flags);
1700 num_slabs += active_slabs;
1701 num_objs = num_slabs * cachep->num;
1703 " node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
1704 node, active_slabs, num_slabs, active_objs, num_objs,
1710 * Interface to system's page allocator. No need to hold the cache-lock.
1712 * If we requested dmaable memory, we will get it. Even if we
1713 * did not request dmaable memory, we might get it, but that
1714 * would be relatively rare and ignorable.
1716 static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
1722 flags |= cachep->allocflags;
1723 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1724 flags |= __GFP_RECLAIMABLE;
1726 page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1728 if (!(flags & __GFP_NOWARN) && printk_ratelimit())
1729 slab_out_of_memory(cachep, flags, nodeid);
1733 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1734 if (unlikely(page->pfmemalloc))
1735 pfmemalloc_active = true;
1737 nr_pages = (1 << cachep->gfporder);
1738 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1739 add_zone_page_state(page_zone(page),
1740 NR_SLAB_RECLAIMABLE, nr_pages);
1742 add_zone_page_state(page_zone(page),
1743 NR_SLAB_UNRECLAIMABLE, nr_pages);
1744 __SetPageSlab(page);
1745 if (page->pfmemalloc)
1746 SetPageSlabPfmemalloc(page);
1747 memcg_bind_pages(cachep, cachep->gfporder);
1749 if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1750 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1753 kmemcheck_mark_uninitialized_pages(page, nr_pages);
1755 kmemcheck_mark_unallocated_pages(page, nr_pages);
1762 * Interface to system's page release.
1764 static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
1766 const unsigned long nr_freed = (1 << cachep->gfporder);
1768 kmemcheck_free_shadow(page, cachep->gfporder);
1770 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1771 sub_zone_page_state(page_zone(page),
1772 NR_SLAB_RECLAIMABLE, nr_freed);
1774 sub_zone_page_state(page_zone(page),
1775 NR_SLAB_UNRECLAIMABLE, nr_freed);
1777 BUG_ON(!PageSlab(page));
1778 __ClearPageSlabPfmemalloc(page);
1779 __ClearPageSlab(page);
1781 memcg_release_pages(cachep, cachep->gfporder);
1782 if (current->reclaim_state)
1783 current->reclaim_state->reclaimed_slab += nr_freed;
1784 __free_memcg_kmem_pages(page, cachep->gfporder);
1787 static void kmem_rcu_free(struct rcu_head *head)
1789 struct kmem_cache *cachep;
1792 page = container_of(head, struct page, rcu_head);
1793 cachep = page->slab_cache;
1795 kmem_freepages(cachep, page);
1800 #ifdef CONFIG_DEBUG_PAGEALLOC
1801 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1802 unsigned long caller)
1804 int size = cachep->object_size;
1806 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1808 if (size < 5 * sizeof(unsigned long))
1811 *addr++ = 0x12345678;
1813 *addr++ = smp_processor_id();
1814 size -= 3 * sizeof(unsigned long);
1816 unsigned long *sptr = &caller;
1817 unsigned long svalue;
1819 while (!kstack_end(sptr)) {
1821 if (kernel_text_address(svalue)) {
1823 size -= sizeof(unsigned long);
1824 if (size <= sizeof(unsigned long))
1830 *addr++ = 0x87654321;
1834 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1836 int size = cachep->object_size;
1837 addr = &((char *)addr)[obj_offset(cachep)];
1839 memset(addr, val, size);
1840 *(unsigned char *)(addr + size - 1) = POISON_END;
1843 static void dump_line(char *data, int offset, int limit)
1846 unsigned char error = 0;
1849 printk(KERN_ERR "%03x: ", offset);
1850 for (i = 0; i < limit; i++) {
1851 if (data[offset + i] != POISON_FREE) {
1852 error = data[offset + i];
1856 print_hex_dump(KERN_CONT, "", 0, 16, 1,
1857 &data[offset], limit, 1);
1859 if (bad_count == 1) {
1860 error ^= POISON_FREE;
1861 if (!(error & (error - 1))) {
1862 printk(KERN_ERR "Single bit error detected. Probably "
1865 printk(KERN_ERR "Run memtest86+ or a similar memory "
1868 printk(KERN_ERR "Run a memory test tool.\n");
1877 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1882 if (cachep->flags & SLAB_RED_ZONE) {
1883 printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n",
1884 *dbg_redzone1(cachep, objp),
1885 *dbg_redzone2(cachep, objp));
1888 if (cachep->flags & SLAB_STORE_USER) {
1889 printk(KERN_ERR "Last user: [<%p>](%pSR)\n",
1890 *dbg_userword(cachep, objp),
1891 *dbg_userword(cachep, objp));
1893 realobj = (char *)objp + obj_offset(cachep);
1894 size = cachep->object_size;
1895 for (i = 0; i < size && lines; i += 16, lines--) {
1898 if (i + limit > size)
1900 dump_line(realobj, i, limit);
1904 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1910 realobj = (char *)objp + obj_offset(cachep);
1911 size = cachep->object_size;
1913 for (i = 0; i < size; i++) {
1914 char exp = POISON_FREE;
1917 if (realobj[i] != exp) {
1923 "Slab corruption (%s): %s start=%p, len=%d\n",
1924 print_tainted(), cachep->name, realobj, size);
1925 print_objinfo(cachep, objp, 0);
1927 /* Hexdump the affected line */
1930 if (i + limit > size)
1932 dump_line(realobj, i, limit);
1935 /* Limit to 5 lines */
1941 /* Print some data about the neighboring objects, if they
1944 struct slab *slabp = virt_to_slab(objp);
1947 objnr = obj_to_index(cachep, slabp, objp);
1949 objp = index_to_obj(cachep, slabp, objnr - 1);
1950 realobj = (char *)objp + obj_offset(cachep);
1951 printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1953 print_objinfo(cachep, objp, 2);
1955 if (objnr + 1 < cachep->num) {
1956 objp = index_to_obj(cachep, slabp, objnr + 1);
1957 realobj = (char *)objp + obj_offset(cachep);
1958 printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1960 print_objinfo(cachep, objp, 2);
1967 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
1970 for (i = 0; i < cachep->num; i++) {
1971 void *objp = index_to_obj(cachep, slabp, i);
1973 if (cachep->flags & SLAB_POISON) {
1974 #ifdef CONFIG_DEBUG_PAGEALLOC
1975 if (cachep->size % PAGE_SIZE == 0 &&
1977 kernel_map_pages(virt_to_page(objp),
1978 cachep->size / PAGE_SIZE, 1);
1980 check_poison_obj(cachep, objp);
1982 check_poison_obj(cachep, objp);
1985 if (cachep->flags & SLAB_RED_ZONE) {
1986 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1987 slab_error(cachep, "start of a freed object "
1989 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1990 slab_error(cachep, "end of a freed object "
1996 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
2002 * slab_destroy - destroy and release all objects in a slab
2003 * @cachep: cache pointer being destroyed
2004 * @slabp: slab pointer being destroyed
2006 * Destroy all the objs in a slab, and release the mem back to the system.
2007 * Before calling the slab must have been unlinked from the cache. The
2008 * cache-lock is not held/needed.
2010 static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
2012 struct page *page = virt_to_head_page(slabp->s_mem);
2014 slab_destroy_debugcheck(cachep, slabp);
2015 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
2016 struct rcu_head *head;
2019 * RCU free overloads the RCU head over the LRU.
2020 * slab_page has been overloeaded over the LRU,
2021 * however it is not used from now on so that
2022 * we can use it safely.
2024 head = (void *)&page->rcu_head;
2025 call_rcu(head, kmem_rcu_free);
2028 kmem_freepages(cachep, page);
2032 * From now on, we don't use slab management
2033 * although actual page can be freed in rcu context
2035 if (OFF_SLAB(cachep))
2036 kmem_cache_free(cachep->slabp_cache, slabp);
2040 * calculate_slab_order - calculate size (page order) of slabs
2041 * @cachep: pointer to the cache that is being created
2042 * @size: size of objects to be created in this cache.
2043 * @align: required alignment for the objects.
2044 * @flags: slab allocation flags
2046 * Also calculates the number of objects per slab.
2048 * This could be made much more intelligent. For now, try to avoid using
2049 * high order pages for slabs. When the gfp() functions are more friendly
2050 * towards high-order requests, this should be changed.
2052 static size_t calculate_slab_order(struct kmem_cache *cachep,
2053 size_t size, size_t align, unsigned long flags)
2055 unsigned long offslab_limit;
2056 size_t left_over = 0;
2059 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
2063 cache_estimate(gfporder, size, align, flags, &remainder, &num);
2067 if (flags & CFLGS_OFF_SLAB) {
2069 * Max number of objs-per-slab for caches which
2070 * use off-slab slabs. Needed to avoid a possible
2071 * looping condition in cache_grow().
2073 offslab_limit = size - sizeof(struct slab);
2074 offslab_limit /= sizeof(kmem_bufctl_t);
2076 if (num > offslab_limit)
2080 /* Found something acceptable - save it away */
2082 cachep->gfporder = gfporder;
2083 left_over = remainder;
2086 * A VFS-reclaimable slab tends to have most allocations
2087 * as GFP_NOFS and we really don't want to have to be allocating
2088 * higher-order pages when we are unable to shrink dcache.
2090 if (flags & SLAB_RECLAIM_ACCOUNT)
2094 * Large number of objects is good, but very large slabs are
2095 * currently bad for the gfp()s.
2097 if (gfporder >= slab_max_order)
2101 * Acceptable internal fragmentation?
2103 if (left_over * 8 <= (PAGE_SIZE << gfporder))
2109 static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
2111 if (slab_state >= FULL)
2112 return enable_cpucache(cachep, gfp);
2114 if (slab_state == DOWN) {
2116 * Note: Creation of first cache (kmem_cache).
2117 * The setup_node is taken care
2118 * of by the caller of __kmem_cache_create
2120 cachep->array[smp_processor_id()] = &initarray_generic.cache;
2121 slab_state = PARTIAL;
2122 } else if (slab_state == PARTIAL) {
2124 * Note: the second kmem_cache_create must create the cache
2125 * that's used by kmalloc(24), otherwise the creation of
2126 * further caches will BUG().
2128 cachep->array[smp_processor_id()] = &initarray_generic.cache;
2131 * If the cache that's used by kmalloc(sizeof(kmem_cache_node)) is
2132 * the second cache, then we need to set up all its node/,
2133 * otherwise the creation of further caches will BUG().
2135 set_up_node(cachep, SIZE_AC);
2136 if (INDEX_AC == INDEX_NODE)
2137 slab_state = PARTIAL_NODE;
2139 slab_state = PARTIAL_ARRAYCACHE;
2141 /* Remaining boot caches */
2142 cachep->array[smp_processor_id()] =
2143 kmalloc(sizeof(struct arraycache_init), gfp);
2145 if (slab_state == PARTIAL_ARRAYCACHE) {
2146 set_up_node(cachep, SIZE_NODE);
2147 slab_state = PARTIAL_NODE;
2150 for_each_online_node(node) {
2151 cachep->node[node] =
2152 kmalloc_node(sizeof(struct kmem_cache_node),
2154 BUG_ON(!cachep->node[node]);
2155 kmem_cache_node_init(cachep->node[node]);
2159 cachep->node[numa_mem_id()]->next_reap =
2160 jiffies + REAPTIMEOUT_LIST3 +
2161 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
2163 cpu_cache_get(cachep)->avail = 0;
2164 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
2165 cpu_cache_get(cachep)->batchcount = 1;
2166 cpu_cache_get(cachep)->touched = 0;
2167 cachep->batchcount = 1;
2168 cachep->limit = BOOT_CPUCACHE_ENTRIES;
2173 * __kmem_cache_create - Create a cache.
2174 * @cachep: cache management descriptor
2175 * @flags: SLAB flags
2177 * Returns a ptr to the cache on success, NULL on failure.
2178 * Cannot be called within a int, but can be interrupted.
2179 * The @ctor is run when new pages are allocated by the cache.
2183 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2184 * to catch references to uninitialised memory.
2186 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2187 * for buffer overruns.
2189 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2190 * cacheline. This can be beneficial if you're counting cycles as closely
2194 __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
2196 size_t left_over, slab_size, ralign;
2199 size_t size = cachep->size;
2204 * Enable redzoning and last user accounting, except for caches with
2205 * large objects, if the increased size would increase the object size
2206 * above the next power of two: caches with object sizes just above a
2207 * power of two have a significant amount of internal fragmentation.
2209 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2210 2 * sizeof(unsigned long long)))
2211 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2212 if (!(flags & SLAB_DESTROY_BY_RCU))
2213 flags |= SLAB_POISON;
2215 if (flags & SLAB_DESTROY_BY_RCU)
2216 BUG_ON(flags & SLAB_POISON);
2220 * Check that size is in terms of words. This is needed to avoid
2221 * unaligned accesses for some archs when redzoning is used, and makes
2222 * sure any on-slab bufctl's are also correctly aligned.
2224 if (size & (BYTES_PER_WORD - 1)) {
2225 size += (BYTES_PER_WORD - 1);
2226 size &= ~(BYTES_PER_WORD - 1);
2230 * Redzoning and user store require word alignment or possibly larger.
2231 * Note this will be overridden by architecture or caller mandated
2232 * alignment if either is greater than BYTES_PER_WORD.
2234 if (flags & SLAB_STORE_USER)
2235 ralign = BYTES_PER_WORD;
2237 if (flags & SLAB_RED_ZONE) {
2238 ralign = REDZONE_ALIGN;
2239 /* If redzoning, ensure that the second redzone is suitably
2240 * aligned, by adjusting the object size accordingly. */
2241 size += REDZONE_ALIGN - 1;
2242 size &= ~(REDZONE_ALIGN - 1);
2245 /* 3) caller mandated alignment */
2246 if (ralign < cachep->align) {
2247 ralign = cachep->align;
2249 /* disable debug if necessary */
2250 if (ralign > __alignof__(unsigned long long))
2251 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2255 cachep->align = ralign;
2257 if (slab_is_available())
2262 setup_node_pointer(cachep);
2266 * Both debugging options require word-alignment which is calculated
2269 if (flags & SLAB_RED_ZONE) {
2270 /* add space for red zone words */
2271 cachep->obj_offset += sizeof(unsigned long long);
2272 size += 2 * sizeof(unsigned long long);
2274 if (flags & SLAB_STORE_USER) {
2275 /* user store requires one word storage behind the end of
2276 * the real object. But if the second red zone needs to be
2277 * aligned to 64 bits, we must allow that much space.
2279 if (flags & SLAB_RED_ZONE)
2280 size += REDZONE_ALIGN;
2282 size += BYTES_PER_WORD;
2284 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2285 if (size >= kmalloc_size(INDEX_NODE + 1)
2286 && cachep->object_size > cache_line_size()
2287 && ALIGN(size, cachep->align) < PAGE_SIZE) {
2288 cachep->obj_offset += PAGE_SIZE - ALIGN(size, cachep->align);
2295 * Determine if the slab management is 'on' or 'off' slab.
2296 * (bootstrapping cannot cope with offslab caches so don't do
2297 * it too early on. Always use on-slab management when
2298 * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
2300 if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init &&
2301 !(flags & SLAB_NOLEAKTRACE))
2303 * Size is large, assume best to place the slab management obj
2304 * off-slab (should allow better packing of objs).
2306 flags |= CFLGS_OFF_SLAB;
2308 size = ALIGN(size, cachep->align);
2310 left_over = calculate_slab_order(cachep, size, cachep->align, flags);
2315 slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
2316 + sizeof(struct slab), cachep->align);
2319 * If the slab has been placed off-slab, and we have enough space then
2320 * move it on-slab. This is at the expense of any extra colouring.
2322 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
2323 flags &= ~CFLGS_OFF_SLAB;
2324 left_over -= slab_size;
2327 if (flags & CFLGS_OFF_SLAB) {
2328 /* really off slab. No need for manual alignment */
2330 cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
2332 #ifdef CONFIG_PAGE_POISONING
2333 /* If we're going to use the generic kernel_map_pages()
2334 * poisoning, then it's going to smash the contents of
2335 * the redzone and userword anyhow, so switch them off.
2337 if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
2338 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2342 cachep->colour_off = cache_line_size();
2343 /* Offset must be a multiple of the alignment. */
2344 if (cachep->colour_off < cachep->align)
2345 cachep->colour_off = cachep->align;
2346 cachep->colour = left_over / cachep->colour_off;
2347 cachep->slab_size = slab_size;
2348 cachep->flags = flags;
2349 cachep->allocflags = __GFP_COMP;
2350 if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
2351 cachep->allocflags |= GFP_DMA;
2352 cachep->size = size;
2353 cachep->reciprocal_buffer_size = reciprocal_value(size);
2355 if (flags & CFLGS_OFF_SLAB) {
2356 cachep->slabp_cache = kmalloc_slab(slab_size, 0u);
2358 * This is a possibility for one of the malloc_sizes caches.
2359 * But since we go off slab only for object size greater than
2360 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2361 * this should not happen at all.
2362 * But leave a BUG_ON for some lucky dude.
2364 BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
2367 err = setup_cpu_cache(cachep, gfp);
2369 __kmem_cache_shutdown(cachep);
2373 if (flags & SLAB_DEBUG_OBJECTS) {
2375 * Would deadlock through slab_destroy()->call_rcu()->
2376 * debug_object_activate()->kmem_cache_alloc().
2378 WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
2380 slab_set_debugobj_lock_classes(cachep);
2381 } else if (!OFF_SLAB(cachep) && !(flags & SLAB_DESTROY_BY_RCU))
2382 on_slab_lock_classes(cachep);
2388 static void check_irq_off(void)
2390 BUG_ON(!irqs_disabled());
2393 static void check_irq_on(void)
2395 BUG_ON(irqs_disabled());
2398 static void check_spinlock_acquired(struct kmem_cache *cachep)
2402 assert_spin_locked(&cachep->node[numa_mem_id()]->list_lock);
2406 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2410 assert_spin_locked(&cachep->node[node]->list_lock);
2415 #define check_irq_off() do { } while(0)
2416 #define check_irq_on() do { } while(0)
2417 #define check_spinlock_acquired(x) do { } while(0)
2418 #define check_spinlock_acquired_node(x, y) do { } while(0)
2421 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
2422 struct array_cache *ac,
2423 int force, int node);
2425 static void do_drain(void *arg)
2427 struct kmem_cache *cachep = arg;
2428 struct array_cache *ac;
2429 int node = numa_mem_id();
2432 ac = cpu_cache_get(cachep);
2433 spin_lock(&cachep->node[node]->list_lock);
2434 free_block(cachep, ac->entry, ac->avail, node);
2435 spin_unlock(&cachep->node[node]->list_lock);
2439 static void drain_cpu_caches(struct kmem_cache *cachep)
2441 struct kmem_cache_node *n;
2444 on_each_cpu(do_drain, cachep, 1);
2446 for_each_online_node(node) {
2447 n = cachep->node[node];
2449 drain_alien_cache(cachep, n->alien);
2452 for_each_online_node(node) {
2453 n = cachep->node[node];
2455 drain_array(cachep, n, n->shared, 1, node);
2460 * Remove slabs from the list of free slabs.
2461 * Specify the number of slabs to drain in tofree.
2463 * Returns the actual number of slabs released.
2465 static int drain_freelist(struct kmem_cache *cache,
2466 struct kmem_cache_node *n, int tofree)
2468 struct list_head *p;
2473 while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
2475 spin_lock_irq(&n->list_lock);
2476 p = n->slabs_free.prev;
2477 if (p == &n->slabs_free) {
2478 spin_unlock_irq(&n->list_lock);
2482 slabp = list_entry(p, struct slab, list);
2484 BUG_ON(slabp->inuse);
2486 list_del(&slabp->list);
2488 * Safe to drop the lock. The slab is no longer linked
2491 n->free_objects -= cache->num;
2492 spin_unlock_irq(&n->list_lock);
2493 slab_destroy(cache, slabp);
2500 /* Called with slab_mutex held to protect against cpu hotplug */
2501 static int __cache_shrink(struct kmem_cache *cachep)
2504 struct kmem_cache_node *n;
2506 drain_cpu_caches(cachep);
2509 for_each_online_node(i) {
2510 n = cachep->node[i];
2514 drain_freelist(cachep, n, slabs_tofree(cachep, n));
2516 ret += !list_empty(&n->slabs_full) ||
2517 !list_empty(&n->slabs_partial);
2519 return (ret ? 1 : 0);
2523 * kmem_cache_shrink - Shrink a cache.
2524 * @cachep: The cache to shrink.
2526 * Releases as many slabs as possible for a cache.
2527 * To help debugging, a zero exit status indicates all slabs were released.
2529 int kmem_cache_shrink(struct kmem_cache *cachep)
2532 BUG_ON(!cachep || in_interrupt());
2535 mutex_lock(&slab_mutex);
2536 ret = __cache_shrink(cachep);
2537 mutex_unlock(&slab_mutex);
2541 EXPORT_SYMBOL(kmem_cache_shrink);
2543 int __kmem_cache_shutdown(struct kmem_cache *cachep)
2546 struct kmem_cache_node *n;
2547 int rc = __cache_shrink(cachep);
2552 for_each_online_cpu(i)
2553 kfree(cachep->array[i]);
2555 /* NUMA: free the node structures */
2556 for_each_online_node(i) {
2557 n = cachep->node[i];
2560 free_alien_cache(n->alien);
2568 * Get the memory for a slab management obj.
2569 * For a slab cache when the slab descriptor is off-slab, slab descriptors
2570 * always come from malloc_sizes caches. The slab descriptor cannot
2571 * come from the same cache which is getting created because,
2572 * when we are searching for an appropriate cache for these
2573 * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2574 * If we are creating a malloc_sizes cache here it would not be visible to
2575 * kmem_find_general_cachep till the initialization is complete.
2576 * Hence we cannot have slabp_cache same as the original cache.
2578 static struct slab *alloc_slabmgmt(struct kmem_cache *cachep,
2579 struct page *page, int colour_off,
2580 gfp_t local_flags, int nodeid)
2583 void *addr = page_address(page);
2585 if (OFF_SLAB(cachep)) {
2586 /* Slab management obj is off-slab. */
2587 slabp = kmem_cache_alloc_node(cachep->slabp_cache,
2588 local_flags, nodeid);
2590 * If the first object in the slab is leaked (it's allocated
2591 * but no one has a reference to it), we want to make sure
2592 * kmemleak does not treat the ->s_mem pointer as a reference
2593 * to the object. Otherwise we will not report the leak.
2595 kmemleak_scan_area(&slabp->list, sizeof(struct list_head),
2600 slabp = addr + colour_off;
2601 colour_off += cachep->slab_size;
2604 slabp->s_mem = addr + colour_off;
2609 static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
2611 return (kmem_bufctl_t *) (slabp + 1);
2614 static void cache_init_objs(struct kmem_cache *cachep,
2619 for (i = 0; i < cachep->num; i++) {
2620 void *objp = index_to_obj(cachep, slabp, i);
2622 /* need to poison the objs? */
2623 if (cachep->flags & SLAB_POISON)
2624 poison_obj(cachep, objp, POISON_FREE);
2625 if (cachep->flags & SLAB_STORE_USER)
2626 *dbg_userword(cachep, objp) = NULL;
2628 if (cachep->flags & SLAB_RED_ZONE) {
2629 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2630 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2633 * Constructors are not allowed to allocate memory from the same
2634 * cache which they are a constructor for. Otherwise, deadlock.
2635 * They must also be threaded.
2637 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2638 cachep->ctor(objp + obj_offset(cachep));
2640 if (cachep->flags & SLAB_RED_ZONE) {
2641 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2642 slab_error(cachep, "constructor overwrote the"
2643 " end of an object");
2644 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2645 slab_error(cachep, "constructor overwrote the"
2646 " start of an object");
2648 if ((cachep->size % PAGE_SIZE) == 0 &&
2649 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2650 kernel_map_pages(virt_to_page(objp),
2651 cachep->size / PAGE_SIZE, 0);
2656 slab_bufctl(slabp)[i] = i + 1;
2658 slab_bufctl(slabp)[i - 1] = BUFCTL_END;
2661 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2663 if (CONFIG_ZONE_DMA_FLAG) {
2664 if (flags & GFP_DMA)
2665 BUG_ON(!(cachep->allocflags & GFP_DMA));
2667 BUG_ON(cachep->allocflags & GFP_DMA);
2671 static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
2674 void *objp = index_to_obj(cachep, slabp, slabp->free);
2678 next = slab_bufctl(slabp)[slabp->free];
2680 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2681 WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);
2688 static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
2689 void *objp, int nodeid)
2691 unsigned int objnr = obj_to_index(cachep, slabp, objp);
2694 /* Verify that the slab belongs to the intended node */
2695 WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);
2697 if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
2698 printk(KERN_ERR "slab: double free detected in cache "
2699 "'%s', objp %p\n", cachep->name, objp);
2703 slab_bufctl(slabp)[objnr] = slabp->free;
2704 slabp->free = objnr;
2709 * Map pages beginning at addr to the given cache and slab. This is required
2710 * for the slab allocator to be able to lookup the cache and slab of a
2711 * virtual address for kfree, ksize, and slab debugging.
2713 static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
2716 page->slab_cache = cache;
2717 page->slab_page = slab;
2721 * Grow (by 1) the number of slabs within a cache. This is called by
2722 * kmem_cache_alloc() when there are no active objs left in a cache.
2724 static int cache_grow(struct kmem_cache *cachep,
2725 gfp_t flags, int nodeid, struct page *page)
2730 struct kmem_cache_node *n;
2733 * Be lazy and only check for valid flags here, keeping it out of the
2734 * critical path in kmem_cache_alloc().
2736 BUG_ON(flags & GFP_SLAB_BUG_MASK);
2737 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2739 /* Take the node list lock to change the colour_next on this node */
2741 n = cachep->node[nodeid];
2742 spin_lock(&n->list_lock);
2744 /* Get colour for the slab, and cal the next value. */
2745 offset = n->colour_next;
2747 if (n->colour_next >= cachep->colour)
2749 spin_unlock(&n->list_lock);
2751 offset *= cachep->colour_off;
2753 if (local_flags & __GFP_WAIT)
2757 * The test for missing atomic flag is performed here, rather than
2758 * the more obvious place, simply to reduce the critical path length
2759 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2760 * will eventually be caught here (where it matters).
2762 kmem_flagcheck(cachep, flags);
2765 * Get mem for the objs. Attempt to allocate a physical page from
2769 page = kmem_getpages(cachep, local_flags, nodeid);
2773 /* Get slab management. */
2774 slabp = alloc_slabmgmt(cachep, page, offset,
2775 local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
2779 slab_map_pages(cachep, slabp, page);
2781 cache_init_objs(cachep, slabp);
2783 if (local_flags & __GFP_WAIT)
2784 local_irq_disable();
2786 spin_lock(&n->list_lock);
2788 /* Make slab active. */
2789 list_add_tail(&slabp->list, &(n->slabs_free));
2790 STATS_INC_GROWN(cachep);
2791 n->free_objects += cachep->num;
2792 spin_unlock(&n->list_lock);
2795 kmem_freepages(cachep, page);
2797 if (local_flags & __GFP_WAIT)
2798 local_irq_disable();
2805 * Perform extra freeing checks:
2806 * - detect bad pointers.
2807 * - POISON/RED_ZONE checking
2809 static void kfree_debugcheck(const void *objp)
2811 if (!virt_addr_valid(objp)) {
2812 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2813 (unsigned long)objp);
2818 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2820 unsigned long long redzone1, redzone2;
2822 redzone1 = *dbg_redzone1(cache, obj);
2823 redzone2 = *dbg_redzone2(cache, obj);
2828 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2831 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2832 slab_error(cache, "double free detected");
2834 slab_error(cache, "memory outside object was overwritten");
2836 printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
2837 obj, redzone1, redzone2);
2840 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2841 unsigned long caller)
2846 BUG_ON(virt_to_cache(objp) != cachep);
2848 objp -= obj_offset(cachep);
2849 kfree_debugcheck(objp);
2850 slabp = virt_to_slab(objp);
2852 if (cachep->flags & SLAB_RED_ZONE) {
2853 verify_redzone_free(cachep, objp);
2854 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2855 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2857 if (cachep->flags & SLAB_STORE_USER)
2858 *dbg_userword(cachep, objp) = (void *)caller;
2860 objnr = obj_to_index(cachep, slabp, objp);
2862 BUG_ON(objnr >= cachep->num);
2863 BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
2865 #ifdef CONFIG_DEBUG_SLAB_LEAK
2866 slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
2868 if (cachep->flags & SLAB_POISON) {
2869 #ifdef CONFIG_DEBUG_PAGEALLOC
2870 if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2871 store_stackinfo(cachep, objp, caller);
2872 kernel_map_pages(virt_to_page(objp),
2873 cachep->size / PAGE_SIZE, 0);
2875 poison_obj(cachep, objp, POISON_FREE);
2878 poison_obj(cachep, objp, POISON_FREE);
2884 static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
2889 /* Check slab's freelist to see if this obj is there. */
2890 for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
2892 if (entries > cachep->num || i >= cachep->num)
2895 if (entries != cachep->num - slabp->inuse) {
2897 printk(KERN_ERR "slab: Internal list corruption detected in "
2898 "cache '%s'(%d), slabp %p(%d). Tainted(%s). Hexdump:\n",
2899 cachep->name, cachep->num, slabp, slabp->inuse,
2901 print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp,
2902 sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t),
2908 #define kfree_debugcheck(x) do { } while(0)
2909 #define cache_free_debugcheck(x,objp,z) (objp)
2910 #define check_slabp(x,y) do { } while(0)
2913 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags,
2917 struct kmem_cache_node *n;
2918 struct array_cache *ac;
2922 node = numa_mem_id();
2923 if (unlikely(force_refill))
2926 ac = cpu_cache_get(cachep);
2927 batchcount = ac->batchcount;
2928 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2930 * If there was little recent activity on this cache, then
2931 * perform only a partial refill. Otherwise we could generate
2934 batchcount = BATCHREFILL_LIMIT;
2936 n = cachep->node[node];
2938 BUG_ON(ac->avail > 0 || !n);
2939 spin_lock(&n->list_lock);
2941 /* See if we can refill from the shared array */
2942 if (n->shared && transfer_objects(ac, n->shared, batchcount)) {
2943 n->shared->touched = 1;
2947 while (batchcount > 0) {
2948 struct list_head *entry;
2950 /* Get slab alloc is to come from. */
2951 entry = n->slabs_partial.next;
2952 if (entry == &n->slabs_partial) {
2953 n->free_touched = 1;
2954 entry = n->slabs_free.next;
2955 if (entry == &n->slabs_free)
2959 slabp = list_entry(entry, struct slab, list);
2960 check_slabp(cachep, slabp);
2961 check_spinlock_acquired(cachep);
2964 * The slab was either on partial or free list so
2965 * there must be at least one object available for
2968 BUG_ON(slabp->inuse >= cachep->num);
2970 while (slabp->inuse < cachep->num && batchcount--) {
2971 STATS_INC_ALLOCED(cachep);
2972 STATS_INC_ACTIVE(cachep);
2973 STATS_SET_HIGH(cachep);
2975 ac_put_obj(cachep, ac, slab_get_obj(cachep, slabp,
2978 check_slabp(cachep, slabp);
2980 /* move slabp to correct slabp list: */
2981 list_del(&slabp->list);
2982 if (slabp->free == BUFCTL_END)
2983 list_add(&slabp->list, &n->slabs_full);
2985 list_add(&slabp->list, &n->slabs_partial);
2989 n->free_objects -= ac->avail;
2991 spin_unlock(&n->list_lock);
2993 if (unlikely(!ac->avail)) {
2996 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
2998 /* cache_grow can reenable interrupts, then ac could change. */
2999 ac = cpu_cache_get(cachep);
3000 node = numa_mem_id();
3002 /* no objects in sight? abort */
3003 if (!x && (ac->avail == 0 || force_refill))
3006 if (!ac->avail) /* objects refilled by interrupt? */
3011 return ac_get_obj(cachep, ac, flags, force_refill);
3014 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
3017 might_sleep_if(flags & __GFP_WAIT);
3019 kmem_flagcheck(cachep, flags);
3024 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
3025 gfp_t flags, void *objp, unsigned long caller)
3029 if (cachep->flags & SLAB_POISON) {
3030 #ifdef CONFIG_DEBUG_PAGEALLOC
3031 if ((cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
3032 kernel_map_pages(virt_to_page(objp),
3033 cachep->size / PAGE_SIZE, 1);
3035 check_poison_obj(cachep, objp);
3037 check_poison_obj(cachep, objp);
3039 poison_obj(cachep, objp, POISON_INUSE);
3041 if (cachep->flags & SLAB_STORE_USER)
3042 *dbg_userword(cachep, objp) = (void *)caller;
3044 if (cachep->flags & SLAB_RED_ZONE) {
3045 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
3046 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
3047 slab_error(cachep, "double free, or memory outside"
3048 " object was overwritten");
3050 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3051 objp, *dbg_redzone1(cachep, objp),
3052 *dbg_redzone2(cachep, objp));
3054 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
3055 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
3057 #ifdef CONFIG_DEBUG_SLAB_LEAK
3062 slabp = virt_to_slab(objp);
3063 objnr = (unsigned)(objp - slabp->s_mem) / cachep->size;
3064 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
3067 objp += obj_offset(cachep);
3068 if (cachep->ctor && cachep->flags & SLAB_POISON)
3070 if (ARCH_SLAB_MINALIGN &&
3071 ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
3072 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3073 objp, (int)ARCH_SLAB_MINALIGN);
3078 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3081 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
3083 if (cachep == kmem_cache)
3086 return should_failslab(cachep->object_size, flags, cachep->flags);
3089 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3092 struct array_cache *ac;
3093 bool force_refill = false;
3097 ac = cpu_cache_get(cachep);
3098 if (likely(ac->avail)) {
3100 objp = ac_get_obj(cachep, ac, flags, false);
3103 * Allow for the possibility all avail objects are not allowed
3104 * by the current flags
3107 STATS_INC_ALLOCHIT(cachep);
3110 force_refill = true;
3113 STATS_INC_ALLOCMISS(cachep);
3114 objp = cache_alloc_refill(cachep, flags, force_refill);
3116 * the 'ac' may be updated by cache_alloc_refill(),
3117 * and kmemleak_erase() requires its correct value.
3119 ac = cpu_cache_get(cachep);
3123 * To avoid a false negative, if an object that is in one of the
3124 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3125 * treat the array pointers as a reference to the object.
3128 kmemleak_erase(&ac->entry[ac->avail]);
3134 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3136 * If we are in_interrupt, then process context, including cpusets and
3137 * mempolicy, may not apply and should not be used for allocation policy.
3139 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3141 int nid_alloc, nid_here;
3143 if (in_interrupt() || (flags & __GFP_THISNODE))
3145 nid_alloc = nid_here = numa_mem_id();
3146 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3147 nid_alloc = cpuset_slab_spread_node();
3148 else if (current->mempolicy)
3149 nid_alloc = slab_node();
3150 if (nid_alloc != nid_here)
3151 return ____cache_alloc_node(cachep, flags, nid_alloc);
3156 * Fallback function if there was no memory available and no objects on a
3157 * certain node and fall back is permitted. First we scan all the
3158 * available node for available objects. If that fails then we
3159 * perform an allocation without specifying a node. This allows the page
3160 * allocator to do its reclaim / fallback magic. We then insert the
3161 * slab into the proper nodelist and then allocate from it.
3163 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3165 struct zonelist *zonelist;
3169 enum zone_type high_zoneidx = gfp_zone(flags);
3172 unsigned int cpuset_mems_cookie;
3174 if (flags & __GFP_THISNODE)
3177 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
3180 cpuset_mems_cookie = get_mems_allowed();
3181 zonelist = node_zonelist(slab_node(), flags);
3185 * Look through allowed nodes for objects available
3186 * from existing per node queues.
3188 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3189 nid = zone_to_nid(zone);
3191 if (cpuset_zone_allowed_hardwall(zone, flags) &&
3193 cache->node[nid]->free_objects) {
3194 obj = ____cache_alloc_node(cache,
3195 flags | GFP_THISNODE, nid);
3203 * This allocation will be performed within the constraints
3204 * of the current cpuset / memory policy requirements.
3205 * We may trigger various forms of reclaim on the allowed
3206 * set and go into memory reserves if necessary.
3210 if (local_flags & __GFP_WAIT)
3212 kmem_flagcheck(cache, flags);
3213 page = kmem_getpages(cache, local_flags, numa_mem_id());
3214 if (local_flags & __GFP_WAIT)
3215 local_irq_disable();
3218 * Insert into the appropriate per node queues
3220 nid = page_to_nid(page);
3221 if (cache_grow(cache, flags, nid, page)) {
3222 obj = ____cache_alloc_node(cache,
3223 flags | GFP_THISNODE, nid);
3226 * Another processor may allocate the
3227 * objects in the slab since we are
3228 * not holding any locks.
3232 /* cache_grow already freed obj */
3238 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !obj))
3244 * A interface to enable slab creation on nodeid
3246 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3249 struct list_head *entry;
3251 struct kmem_cache_node *n;
3255 VM_BUG_ON(nodeid > num_online_nodes());
3256 n = cachep->node[nodeid];
3261 spin_lock(&n->list_lock);
3262 entry = n->slabs_partial.next;
3263 if (entry == &n->slabs_partial) {
3264 n->free_touched = 1;
3265 entry = n->slabs_free.next;
3266 if (entry == &n->slabs_free)
3270 slabp = list_entry(entry, struct slab, list);
3271 check_spinlock_acquired_node(cachep, nodeid);
3272 check_slabp(cachep, slabp);
3274 STATS_INC_NODEALLOCS(cachep);
3275 STATS_INC_ACTIVE(cachep);
3276 STATS_SET_HIGH(cachep);
3278 BUG_ON(slabp->inuse == cachep->num);
3280 obj = slab_get_obj(cachep, slabp, nodeid);
3281 check_slabp(cachep, slabp);
3283 /* move slabp to correct slabp list: */
3284 list_del(&slabp->list);
3286 if (slabp->free == BUFCTL_END)
3287 list_add(&slabp->list, &n->slabs_full);
3289 list_add(&slabp->list, &n->slabs_partial);
3291 spin_unlock(&n->list_lock);
3295 spin_unlock(&n->list_lock);
3296 x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
3300 return fallback_alloc(cachep, flags);
3306 static __always_inline void *
3307 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3308 unsigned long caller)
3310 unsigned long save_flags;
3312 int slab_node = numa_mem_id();
3314 flags &= gfp_allowed_mask;
3316 lockdep_trace_alloc(flags);
3318 if (slab_should_failslab(cachep, flags))
3321 cachep = memcg_kmem_get_cache(cachep, flags);
3323 cache_alloc_debugcheck_before(cachep, flags);
3324 local_irq_save(save_flags);
3326 if (nodeid == NUMA_NO_NODE)
3329 if (unlikely(!cachep->node[nodeid])) {
3330 /* Node not bootstrapped yet */
3331 ptr = fallback_alloc(cachep, flags);
3335 if (nodeid == slab_node) {
3337 * Use the locally cached objects if possible.
3338 * However ____cache_alloc does not allow fallback
3339 * to other nodes. It may fail while we still have
3340 * objects on other nodes available.
3342 ptr = ____cache_alloc(cachep, flags);
3346 /* ___cache_alloc_node can fall back to other nodes */
3347 ptr = ____cache_alloc_node(cachep, flags, nodeid);
3349 local_irq_restore(save_flags);
3350 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3351 kmemleak_alloc_recursive(ptr, cachep->object_size, 1, cachep->flags,
3355 kmemcheck_slab_alloc(cachep, flags, ptr, cachep->object_size);
3357 if (unlikely((flags & __GFP_ZERO) && ptr))
3358 memset(ptr, 0, cachep->object_size);
3363 static __always_inline void *
3364 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3368 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
3369 objp = alternate_node_alloc(cache, flags);
3373 objp = ____cache_alloc(cache, flags);
3376 * We may just have run out of memory on the local node.
3377 * ____cache_alloc_node() knows how to locate memory on other nodes
3380 objp = ____cache_alloc_node(cache, flags, numa_mem_id());
3387 static __always_inline void *
3388 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3390 return ____cache_alloc(cachep, flags);
3393 #endif /* CONFIG_NUMA */
3395 static __always_inline void *
3396 slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
3398 unsigned long save_flags;
3401 flags &= gfp_allowed_mask;
3403 lockdep_trace_alloc(flags);
3405 if (slab_should_failslab(cachep, flags))
3408 cachep = memcg_kmem_get_cache(cachep, flags);
3410 cache_alloc_debugcheck_before(cachep, flags);
3411 local_irq_save(save_flags);
3412 objp = __do_cache_alloc(cachep, flags);
3413 local_irq_restore(save_flags);
3414 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3415 kmemleak_alloc_recursive(objp, cachep->object_size, 1, cachep->flags,
3420 kmemcheck_slab_alloc(cachep, flags, objp, cachep->object_size);
3422 if (unlikely((flags & __GFP_ZERO) && objp))
3423 memset(objp, 0, cachep->object_size);
3429 * Caller needs to acquire correct kmem_list's list_lock
3431 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
3435 struct kmem_cache_node *n;
3437 for (i = 0; i < nr_objects; i++) {
3441 clear_obj_pfmemalloc(&objpp[i]);
3444 slabp = virt_to_slab(objp);
3445 n = cachep->node[node];
3446 list_del(&slabp->list);
3447 check_spinlock_acquired_node(cachep, node);
3448 check_slabp(cachep, slabp);
3449 slab_put_obj(cachep, slabp, objp, node);
3450 STATS_DEC_ACTIVE(cachep);
3452 check_slabp(cachep, slabp);
3454 /* fixup slab chains */
3455 if (slabp->inuse == 0) {
3456 if (n->free_objects > n->free_limit) {
3457 n->free_objects -= cachep->num;
3458 /* No need to drop any previously held
3459 * lock here, even if we have a off-slab slab
3460 * descriptor it is guaranteed to come from
3461 * a different cache, refer to comments before
3464 slab_destroy(cachep, slabp);
3466 list_add(&slabp->list, &n->slabs_free);
3469 /* Unconditionally move a slab to the end of the
3470 * partial list on free - maximum time for the
3471 * other objects to be freed, too.
3473 list_add_tail(&slabp->list, &n->slabs_partial);
3478 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3481 struct kmem_cache_node *n;
3482 int node = numa_mem_id();
3484 batchcount = ac->batchcount;
3486 BUG_ON(!batchcount || batchcount > ac->avail);
3489 n = cachep->node[node];
3490 spin_lock(&n->list_lock);
3492 struct array_cache *shared_array = n->shared;
3493 int max = shared_array->limit - shared_array->avail;
3495 if (batchcount > max)
3497 memcpy(&(shared_array->entry[shared_array->avail]),
3498 ac->entry, sizeof(void *) * batchcount);
3499 shared_array->avail += batchcount;
3504 free_block(cachep, ac->entry, batchcount, node);
3509 struct list_head *p;
3511 p = n->slabs_free.next;
3512 while (p != &(n->slabs_free)) {
3515 slabp = list_entry(p, struct slab, list);
3516 BUG_ON(slabp->inuse);
3521 STATS_SET_FREEABLE(cachep, i);
3524 spin_unlock(&n->list_lock);
3525 ac->avail -= batchcount;
3526 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3530 * Release an obj back to its cache. If the obj has a constructed state, it must
3531 * be in this state _before_ it is released. Called with disabled ints.
3533 static inline void __cache_free(struct kmem_cache *cachep, void *objp,
3534 unsigned long caller)
3536 struct array_cache *ac = cpu_cache_get(cachep);
3539 kmemleak_free_recursive(objp, cachep->flags);
3540 objp = cache_free_debugcheck(cachep, objp, caller);
3542 kmemcheck_slab_free(cachep, objp, cachep->object_size);
3545 * Skip calling cache_free_alien() when the platform is not numa.
3546 * This will avoid cache misses that happen while accessing slabp (which
3547 * is per page memory reference) to get nodeid. Instead use a global
3548 * variable to skip the call, which is mostly likely to be present in
3551 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3554 if (likely(ac->avail < ac->limit)) {
3555 STATS_INC_FREEHIT(cachep);
3557 STATS_INC_FREEMISS(cachep);
3558 cache_flusharray(cachep, ac);
3561 ac_put_obj(cachep, ac, objp);
3565 * kmem_cache_alloc - Allocate an object
3566 * @cachep: The cache to allocate from.
3567 * @flags: See kmalloc().
3569 * Allocate an object from this cache. The flags are only relevant
3570 * if the cache has no available objects.
3572 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3574 void *ret = slab_alloc(cachep, flags, _RET_IP_);
3576 trace_kmem_cache_alloc(_RET_IP_, ret,
3577 cachep->object_size, cachep->size, flags);
3581 EXPORT_SYMBOL(kmem_cache_alloc);
3583 #ifdef CONFIG_TRACING
3585 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
3589 ret = slab_alloc(cachep, flags, _RET_IP_);
3591 trace_kmalloc(_RET_IP_, ret,
3592 size, cachep->size, flags);
3595 EXPORT_SYMBOL(kmem_cache_alloc_trace);
3600 * kmem_cache_alloc_node - Allocate an object on the specified node
3601 * @cachep: The cache to allocate from.
3602 * @flags: See kmalloc().
3603 * @nodeid: node number of the target node.
3605 * Identical to kmem_cache_alloc but it will allocate memory on the given
3606 * node, which can improve the performance for cpu bound structures.
3608 * Fallback to other node is possible if __GFP_THISNODE is not set.
3610 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3612 void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3614 trace_kmem_cache_alloc_node(_RET_IP_, ret,
3615 cachep->object_size, cachep->size,
3620 EXPORT_SYMBOL(kmem_cache_alloc_node);
3622 #ifdef CONFIG_TRACING
3623 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
3630 ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3632 trace_kmalloc_node(_RET_IP_, ret,
3637 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3640 static __always_inline void *
3641 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
3643 struct kmem_cache *cachep;
3645 cachep = kmalloc_slab(size, flags);
3646 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3648 return kmem_cache_alloc_node_trace(cachep, flags, node, size);
3651 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3652 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3654 return __do_kmalloc_node(size, flags, node, _RET_IP_);
3656 EXPORT_SYMBOL(__kmalloc_node);
3658 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3659 int node, unsigned long caller)
3661 return __do_kmalloc_node(size, flags, node, caller);
3663 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3665 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3667 return __do_kmalloc_node(size, flags, node, 0);
3669 EXPORT_SYMBOL(__kmalloc_node);
3670 #endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */
3671 #endif /* CONFIG_NUMA */
3674 * __do_kmalloc - allocate memory
3675 * @size: how many bytes of memory are required.
3676 * @flags: the type of memory to allocate (see kmalloc).
3677 * @caller: function caller for debug tracking of the caller
3679 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3680 unsigned long caller)
3682 struct kmem_cache *cachep;
3685 /* If you want to save a few bytes .text space: replace
3687 * Then kmalloc uses the uninlined functions instead of the inline
3690 cachep = kmalloc_slab(size, flags);
3691 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3693 ret = slab_alloc(cachep, flags, caller);
3695 trace_kmalloc(caller, ret,
3696 size, cachep->size, flags);
3702 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3703 void *__kmalloc(size_t size, gfp_t flags)
3705 return __do_kmalloc(size, flags, _RET_IP_);
3707 EXPORT_SYMBOL(__kmalloc);
3709 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3711 return __do_kmalloc(size, flags, caller);
3713 EXPORT_SYMBOL(__kmalloc_track_caller);
3716 void *__kmalloc(size_t size, gfp_t flags)
3718 return __do_kmalloc(size, flags, 0);
3720 EXPORT_SYMBOL(__kmalloc);
3724 * kmem_cache_free - Deallocate an object
3725 * @cachep: The cache the allocation was from.
3726 * @objp: The previously allocated object.
3728 * Free an object which was previously allocated from this
3731 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3733 unsigned long flags;
3734 cachep = cache_from_obj(cachep, objp);
3738 local_irq_save(flags);
3739 debug_check_no_locks_freed(objp, cachep->object_size);
3740 if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3741 debug_check_no_obj_freed(objp, cachep->object_size);
3742 __cache_free(cachep, objp, _RET_IP_);
3743 local_irq_restore(flags);
3745 trace_kmem_cache_free(_RET_IP_, objp);
3747 EXPORT_SYMBOL(kmem_cache_free);
3750 * kfree - free previously allocated memory
3751 * @objp: pointer returned by kmalloc.
3753 * If @objp is NULL, no operation is performed.
3755 * Don't free memory not originally allocated by kmalloc()
3756 * or you will run into trouble.
3758 void kfree(const void *objp)
3760 struct kmem_cache *c;
3761 unsigned long flags;
3763 trace_kfree(_RET_IP_, objp);
3765 if (unlikely(ZERO_OR_NULL_PTR(objp)))
3767 local_irq_save(flags);
3768 kfree_debugcheck(objp);
3769 c = virt_to_cache(objp);
3770 debug_check_no_locks_freed(objp, c->object_size);
3772 debug_check_no_obj_freed(objp, c->object_size);
3773 __cache_free(c, (void *)objp, _RET_IP_);
3774 local_irq_restore(flags);
3776 EXPORT_SYMBOL(kfree);
3779 * This initializes kmem_cache_node or resizes various caches for all nodes.
3781 static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
3784 struct kmem_cache_node *n;
3785 struct array_cache *new_shared;
3786 struct array_cache **new_alien = NULL;
3788 for_each_online_node(node) {
3790 if (use_alien_caches) {
3791 new_alien = alloc_alien_cache(node, cachep->limit, gfp);
3797 if (cachep->shared) {
3798 new_shared = alloc_arraycache(node,
3799 cachep->shared*cachep->batchcount,
3802 free_alien_cache(new_alien);
3807 n = cachep->node[node];
3809 struct array_cache *shared = n->shared;
3811 spin_lock_irq(&n->list_lock);
3814 free_block(cachep, shared->entry,
3815 shared->avail, node);
3817 n->shared = new_shared;
3819 n->alien = new_alien;
3822 n->free_limit = (1 + nr_cpus_node(node)) *
3823 cachep->batchcount + cachep->num;
3824 spin_unlock_irq(&n->list_lock);
3826 free_alien_cache(new_alien);
3829 n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
3831 free_alien_cache(new_alien);
3836 kmem_cache_node_init(n);
3837 n->next_reap = jiffies + REAPTIMEOUT_LIST3 +
3838 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
3839 n->shared = new_shared;
3840 n->alien = new_alien;
3841 n->free_limit = (1 + nr_cpus_node(node)) *
3842 cachep->batchcount + cachep->num;
3843 cachep->node[node] = n;
3848 if (!cachep->list.next) {
3849 /* Cache is not active yet. Roll back what we did */
3852 if (cachep->node[node]) {
3853 n = cachep->node[node];
3856 free_alien_cache(n->alien);
3858 cachep->node[node] = NULL;
3866 struct ccupdate_struct {
3867 struct kmem_cache *cachep;
3868 struct array_cache *new[0];
3871 static void do_ccupdate_local(void *info)
3873 struct ccupdate_struct *new = info;
3874 struct array_cache *old;
3877 old = cpu_cache_get(new->cachep);
3879 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
3880 new->new[smp_processor_id()] = old;
3883 /* Always called with the slab_mutex held */
3884 static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
3885 int batchcount, int shared, gfp_t gfp)
3887 struct ccupdate_struct *new;
3890 new = kzalloc(sizeof(*new) + nr_cpu_ids * sizeof(struct array_cache *),
3895 for_each_online_cpu(i) {
3896 new->new[i] = alloc_arraycache(cpu_to_mem(i), limit,
3899 for (i--; i >= 0; i--)
3905 new->cachep = cachep;
3907 on_each_cpu(do_ccupdate_local, (void *)new, 1);
3910 cachep->batchcount = batchcount;
3911 cachep->limit = limit;
3912 cachep->shared = shared;
3914 for_each_online_cpu(i) {
3915 struct array_cache *ccold = new->new[i];
3918 spin_lock_irq(&cachep->node[cpu_to_mem(i)]->list_lock);
3919 free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i));
3920 spin_unlock_irq(&cachep->node[cpu_to_mem(i)]->list_lock);
3924 return alloc_kmemlist(cachep, gfp);
3927 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3928 int batchcount, int shared, gfp_t gfp)
3931 struct kmem_cache *c = NULL;
3934 ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3936 if (slab_state < FULL)
3939 if ((ret < 0) || !is_root_cache(cachep))
3942 VM_BUG_ON(!mutex_is_locked(&slab_mutex));
3943 for_each_memcg_cache_index(i) {
3944 c = cache_from_memcg(cachep, i);
3946 /* return value determined by the parent cache only */
3947 __do_tune_cpucache(c, limit, batchcount, shared, gfp);
3953 /* Called with slab_mutex held always */
3954 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3961 if (!is_root_cache(cachep)) {
3962 struct kmem_cache *root = memcg_root_cache(cachep);
3963 limit = root->limit;
3964 shared = root->shared;
3965 batchcount = root->batchcount;
3968 if (limit && shared && batchcount)
3971 * The head array serves three purposes:
3972 * - create a LIFO ordering, i.e. return objects that are cache-warm
3973 * - reduce the number of spinlock operations.
3974 * - reduce the number of linked list operations on the slab and
3975 * bufctl chains: array operations are cheaper.
3976 * The numbers are guessed, we should auto-tune as described by
3979 if (cachep->size > 131072)
3981 else if (cachep->size > PAGE_SIZE)
3983 else if (cachep->size > 1024)
3985 else if (cachep->size > 256)
3991 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3992 * allocation behaviour: Most allocs on one cpu, most free operations
3993 * on another cpu. For these cases, an efficient object passing between
3994 * cpus is necessary. This is provided by a shared array. The array
3995 * replaces Bonwick's magazine layer.
3996 * On uniprocessor, it's functionally equivalent (but less efficient)
3997 * to a larger limit. Thus disabled by default.
4000 if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
4005 * With debugging enabled, large batchcount lead to excessively long
4006 * periods with disabled local interrupts. Limit the batchcount
4011 batchcount = (limit + 1) / 2;
4013 err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
4015 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
4016 cachep->name, -err);
4021 * Drain an array if it contains any elements taking the node lock only if
4022 * necessary. Note that the node listlock also protects the array_cache
4023 * if drain_array() is used on the shared array.
4025 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
4026 struct array_cache *ac, int force, int node)
4030 if (!ac || !ac->avail)
4032 if (ac->touched && !force) {
4035 spin_lock_irq(&n->list_lock);
4037 tofree = force ? ac->avail : (ac->limit + 4) / 5;
4038 if (tofree > ac->avail)
4039 tofree = (ac->avail + 1) / 2;
4040 free_block(cachep, ac->entry, tofree, node);
4041 ac->avail -= tofree;
4042 memmove(ac->entry, &(ac->entry[tofree]),
4043 sizeof(void *) * ac->avail);
4045 spin_unlock_irq(&n->list_lock);
4050 * cache_reap - Reclaim memory from caches.
4051 * @w: work descriptor
4053 * Called from workqueue/eventd every few seconds.
4055 * - clear the per-cpu caches for this CPU.
4056 * - return freeable pages to the main free memory pool.
4058 * If we cannot acquire the cache chain mutex then just give up - we'll try
4059 * again on the next iteration.
4061 static void cache_reap(struct work_struct *w)
4063 struct kmem_cache *searchp;
4064 struct kmem_cache_node *n;
4065 int node = numa_mem_id();
4066 struct delayed_work *work = to_delayed_work(w);
4068 if (!mutex_trylock(&slab_mutex))
4069 /* Give up. Setup the next iteration. */
4072 list_for_each_entry(searchp, &slab_caches, list) {
4076 * We only take the node lock if absolutely necessary and we
4077 * have established with reasonable certainty that
4078 * we can do some work if the lock was obtained.
4080 n = searchp->node[node];
4082 reap_alien(searchp, n);
4084 drain_array(searchp, n, cpu_cache_get(searchp), 0, node);
4087 * These are racy checks but it does not matter
4088 * if we skip one check or scan twice.
4090 if (time_after(n->next_reap, jiffies))
4093 n->next_reap = jiffies + REAPTIMEOUT_LIST3;
4095 drain_array(searchp, n, n->shared, 0, node);
4097 if (n->free_touched)
4098 n->free_touched = 0;
4102 freed = drain_freelist(searchp, n, (n->free_limit +
4103 5 * searchp->num - 1) / (5 * searchp->num));
4104 STATS_ADD_REAPED(searchp, freed);
4110 mutex_unlock(&slab_mutex);
4113 /* Set up the next iteration */
4114 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
4117 #ifdef CONFIG_SLABINFO
4118 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
4121 unsigned long active_objs;
4122 unsigned long num_objs;
4123 unsigned long active_slabs = 0;
4124 unsigned long num_slabs, free_objects = 0, shared_avail = 0;
4128 struct kmem_cache_node *n;
4132 for_each_online_node(node) {
4133 n = cachep->node[node];
4138 spin_lock_irq(&n->list_lock);
4140 list_for_each_entry(slabp, &n->slabs_full, list) {
4141 if (slabp->inuse != cachep->num && !error)
4142 error = "slabs_full accounting error";
4143 active_objs += cachep->num;
4146 list_for_each_entry(slabp, &n->slabs_partial, list) {
4147 if (slabp->inuse == cachep->num && !error)
4148 error = "slabs_partial inuse accounting error";
4149 if (!slabp->inuse && !error)
4150 error = "slabs_partial/inuse accounting error";
4151 active_objs += slabp->inuse;
4154 list_for_each_entry(slabp, &n->slabs_free, list) {
4155 if (slabp->inuse && !error)
4156 error = "slabs_free/inuse accounting error";
4159 free_objects += n->free_objects;
4161 shared_avail += n->shared->avail;
4163 spin_unlock_irq(&n->list_lock);
4165 num_slabs += active_slabs;
4166 num_objs = num_slabs * cachep->num;
4167 if (num_objs - active_objs != free_objects && !error)
4168 error = "free_objects accounting error";
4170 name = cachep->name;
4172 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
4174 sinfo->active_objs = active_objs;
4175 sinfo->num_objs = num_objs;
4176 sinfo->active_slabs = active_slabs;
4177 sinfo->num_slabs = num_slabs;
4178 sinfo->shared_avail = shared_avail;
4179 sinfo->limit = cachep->limit;
4180 sinfo->batchcount = cachep->batchcount;
4181 sinfo->shared = cachep->shared;
4182 sinfo->objects_per_slab = cachep->num;
4183 sinfo->cache_order = cachep->gfporder;
4186 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
4190 unsigned long high = cachep->high_mark;
4191 unsigned long allocs = cachep->num_allocations;
4192 unsigned long grown = cachep->grown;
4193 unsigned long reaped = cachep->reaped;
4194 unsigned long errors = cachep->errors;
4195 unsigned long max_freeable = cachep->max_freeable;
4196 unsigned long node_allocs = cachep->node_allocs;
4197 unsigned long node_frees = cachep->node_frees;
4198 unsigned long overflows = cachep->node_overflow;
4200 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu "
4201 "%4lu %4lu %4lu %4lu %4lu",
4202 allocs, high, grown,
4203 reaped, errors, max_freeable, node_allocs,
4204 node_frees, overflows);
4208 unsigned long allochit = atomic_read(&cachep->allochit);
4209 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4210 unsigned long freehit = atomic_read(&cachep->freehit);
4211 unsigned long freemiss = atomic_read(&cachep->freemiss);
4213 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4214 allochit, allocmiss, freehit, freemiss);
4219 #define MAX_SLABINFO_WRITE 128
4221 * slabinfo_write - Tuning for the slab allocator
4223 * @buffer: user buffer
4224 * @count: data length
4227 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
4228 size_t count, loff_t *ppos)
4230 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4231 int limit, batchcount, shared, res;
4232 struct kmem_cache *cachep;
4234 if (count > MAX_SLABINFO_WRITE)
4236 if (copy_from_user(&kbuf, buffer, count))
4238 kbuf[MAX_SLABINFO_WRITE] = '\0';
4240 tmp = strchr(kbuf, ' ');
4245 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4248 /* Find the cache in the chain of caches. */
4249 mutex_lock(&slab_mutex);
4251 list_for_each_entry(cachep, &slab_caches, list) {
4252 if (!strcmp(cachep->name, kbuf)) {
4253 if (limit < 1 || batchcount < 1 ||
4254 batchcount > limit || shared < 0) {
4257 res = do_tune_cpucache(cachep, limit,
4264 mutex_unlock(&slab_mutex);
4270 #ifdef CONFIG_DEBUG_SLAB_LEAK
4272 static void *leaks_start(struct seq_file *m, loff_t *pos)
4274 mutex_lock(&slab_mutex);
4275 return seq_list_start(&slab_caches, *pos);
4278 static inline int add_caller(unsigned long *n, unsigned long v)
4288 unsigned long *q = p + 2 * i;
4302 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4308 static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
4314 for (i = 0, p = s->s_mem; i < c->num; i++, p += c->size) {
4315 if (slab_bufctl(s)[i] != BUFCTL_ACTIVE)
4317 if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4322 static void show_symbol(struct seq_file *m, unsigned long address)
4324 #ifdef CONFIG_KALLSYMS
4325 unsigned long offset, size;
4326 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4328 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4329 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4331 seq_printf(m, " [%s]", modname);
4335 seq_printf(m, "%p", (void *)address);
4338 static int leaks_show(struct seq_file *m, void *p)
4340 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
4342 struct kmem_cache_node *n;
4344 unsigned long *x = m->private;
4348 if (!(cachep->flags & SLAB_STORE_USER))
4350 if (!(cachep->flags & SLAB_RED_ZONE))
4353 /* OK, we can do it */
4357 for_each_online_node(node) {
4358 n = cachep->node[node];
4363 spin_lock_irq(&n->list_lock);
4365 list_for_each_entry(slabp, &n->slabs_full, list)
4366 handle_slab(x, cachep, slabp);
4367 list_for_each_entry(slabp, &n->slabs_partial, list)
4368 handle_slab(x, cachep, slabp);
4369 spin_unlock_irq(&n->list_lock);
4371 name = cachep->name;
4373 /* Increase the buffer size */
4374 mutex_unlock(&slab_mutex);
4375 m->private = kzalloc(x[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4377 /* Too bad, we are really out */
4379 mutex_lock(&slab_mutex);
4382 *(unsigned long *)m->private = x[0] * 2;
4384 mutex_lock(&slab_mutex);
4385 /* Now make sure this entry will be retried */
4389 for (i = 0; i < x[1]; i++) {
4390 seq_printf(m, "%s: %lu ", name, x[2*i+3]);
4391 show_symbol(m, x[2*i+2]);
4398 static const struct seq_operations slabstats_op = {
4399 .start = leaks_start,
4405 static int slabstats_open(struct inode *inode, struct file *file)
4407 unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL);
4410 ret = seq_open(file, &slabstats_op);
4412 struct seq_file *m = file->private_data;
4413 *n = PAGE_SIZE / (2 * sizeof(unsigned long));
4422 static const struct file_operations proc_slabstats_operations = {
4423 .open = slabstats_open,
4425 .llseek = seq_lseek,
4426 .release = seq_release_private,
4430 static int __init slab_proc_init(void)
4432 #ifdef CONFIG_DEBUG_SLAB_LEAK
4433 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4437 module_init(slab_proc_init);
4441 * ksize - get the actual amount of memory allocated for a given object
4442 * @objp: Pointer to the object
4444 * kmalloc may internally round up allocations and return more memory
4445 * than requested. ksize() can be used to determine the actual amount of
4446 * memory allocated. The caller may use this additional memory, even though
4447 * a smaller amount of memory was initially specified with the kmalloc call.
4448 * The caller must guarantee that objp points to a valid object previously
4449 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4450 * must not be freed during the duration of the call.
4452 size_t ksize(const void *objp)
4455 if (unlikely(objp == ZERO_SIZE_PTR))
4458 return virt_to_cache(objp)->object_size;
4460 EXPORT_SYMBOL(ksize);