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;
166 #define SLAB_LIMIT (((unsigned int)(~0U))-1)
171 * Manages the objs in a slab. Placed either at the beginning of mem allocated
172 * for a slab, or allocated from an general cache.
173 * Slabs are chained into three list: fully used, partial, fully free slabs.
177 struct list_head list;
178 void *s_mem; /* including colour offset */
179 unsigned int inuse; /* num of objs active in slab */
188 * - LIFO ordering, to hand out cache-warm objects from _alloc
189 * - reduce the number of linked list operations
190 * - reduce spinlock operations
192 * The limit is stored in the per-cpu structure to reduce the data cache
199 unsigned int batchcount;
200 unsigned int touched;
203 * Must have this definition in here for the proper
204 * alignment of array_cache. Also simplifies accessing
207 * Entries should not be directly dereferenced as
208 * entries belonging to slabs marked pfmemalloc will
209 * have the lower bits set SLAB_OBJ_PFMEMALLOC
213 #define SLAB_OBJ_PFMEMALLOC 1
214 static inline bool is_obj_pfmemalloc(void *objp)
216 return (unsigned long)objp & SLAB_OBJ_PFMEMALLOC;
219 static inline void set_obj_pfmemalloc(void **objp)
221 *objp = (void *)((unsigned long)*objp | SLAB_OBJ_PFMEMALLOC);
225 static inline void clear_obj_pfmemalloc(void **objp)
227 *objp = (void *)((unsigned long)*objp & ~SLAB_OBJ_PFMEMALLOC);
231 * bootstrap: The caches do not work without cpuarrays anymore, but the
232 * cpuarrays are allocated from the generic caches...
234 #define BOOT_CPUCACHE_ENTRIES 1
235 struct arraycache_init {
236 struct array_cache cache;
237 void *entries[BOOT_CPUCACHE_ENTRIES];
241 * Need this for bootstrapping a per node allocator.
243 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
244 static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS];
245 #define CACHE_CACHE 0
246 #define SIZE_AC MAX_NUMNODES
247 #define SIZE_NODE (2 * MAX_NUMNODES)
249 static int drain_freelist(struct kmem_cache *cache,
250 struct kmem_cache_node *n, int tofree);
251 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
253 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
254 static void cache_reap(struct work_struct *unused);
256 static int slab_early_init = 1;
258 #define INDEX_AC kmalloc_index(sizeof(struct arraycache_init))
259 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
261 static void kmem_cache_node_init(struct kmem_cache_node *parent)
263 INIT_LIST_HEAD(&parent->slabs_full);
264 INIT_LIST_HEAD(&parent->slabs_partial);
265 INIT_LIST_HEAD(&parent->slabs_free);
266 parent->shared = NULL;
267 parent->alien = NULL;
268 parent->colour_next = 0;
269 spin_lock_init(&parent->list_lock);
270 parent->free_objects = 0;
271 parent->free_touched = 0;
274 #define MAKE_LIST(cachep, listp, slab, nodeid) \
276 INIT_LIST_HEAD(listp); \
277 list_splice(&(cachep->node[nodeid]->slab), listp); \
280 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
282 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
283 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
284 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
287 #define CFLGS_OFF_SLAB (0x80000000UL)
288 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
290 #define BATCHREFILL_LIMIT 16
292 * Optimization question: fewer reaps means less probability for unnessary
293 * cpucache drain/refill cycles.
295 * OTOH the cpuarrays can contain lots of objects,
296 * which could lock up otherwise freeable slabs.
298 #define REAPTIMEOUT_CPUC (2*HZ)
299 #define REAPTIMEOUT_LIST3 (4*HZ)
302 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
303 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
304 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
305 #define STATS_INC_GROWN(x) ((x)->grown++)
306 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
307 #define STATS_SET_HIGH(x) \
309 if ((x)->num_active > (x)->high_mark) \
310 (x)->high_mark = (x)->num_active; \
312 #define STATS_INC_ERR(x) ((x)->errors++)
313 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
314 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
315 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
316 #define STATS_SET_FREEABLE(x, i) \
318 if ((x)->max_freeable < i) \
319 (x)->max_freeable = i; \
321 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
322 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
323 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
324 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
326 #define STATS_INC_ACTIVE(x) do { } while (0)
327 #define STATS_DEC_ACTIVE(x) do { } while (0)
328 #define STATS_INC_ALLOCED(x) do { } while (0)
329 #define STATS_INC_GROWN(x) do { } while (0)
330 #define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0)
331 #define STATS_SET_HIGH(x) do { } while (0)
332 #define STATS_INC_ERR(x) do { } while (0)
333 #define STATS_INC_NODEALLOCS(x) do { } while (0)
334 #define STATS_INC_NODEFREES(x) do { } while (0)
335 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
336 #define STATS_SET_FREEABLE(x, i) do { } while (0)
337 #define STATS_INC_ALLOCHIT(x) do { } while (0)
338 #define STATS_INC_ALLOCMISS(x) do { } while (0)
339 #define STATS_INC_FREEHIT(x) do { } while (0)
340 #define STATS_INC_FREEMISS(x) do { } while (0)
346 * memory layout of objects:
348 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
349 * the end of an object is aligned with the end of the real
350 * allocation. Catches writes behind the end of the allocation.
351 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
353 * cachep->obj_offset: The real object.
354 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
355 * cachep->size - 1* BYTES_PER_WORD: last caller address
356 * [BYTES_PER_WORD long]
358 static int obj_offset(struct kmem_cache *cachep)
360 return cachep->obj_offset;
363 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
365 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
366 return (unsigned long long*) (objp + obj_offset(cachep) -
367 sizeof(unsigned long long));
370 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
372 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
373 if (cachep->flags & SLAB_STORE_USER)
374 return (unsigned long long *)(objp + cachep->size -
375 sizeof(unsigned long long) -
377 return (unsigned long long *) (objp + cachep->size -
378 sizeof(unsigned long long));
381 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
383 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
384 return (void **)(objp + cachep->size - BYTES_PER_WORD);
389 #define obj_offset(x) 0
390 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
391 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
392 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
397 * Do not go above this order unless 0 objects fit into the slab or
398 * overridden on the command line.
400 #define SLAB_MAX_ORDER_HI 1
401 #define SLAB_MAX_ORDER_LO 0
402 static int slab_max_order = SLAB_MAX_ORDER_LO;
403 static bool slab_max_order_set __initdata;
405 static inline struct kmem_cache *virt_to_cache(const void *obj)
407 struct page *page = virt_to_head_page(obj);
408 return page->slab_cache;
411 static inline struct slab *virt_to_slab(const void *obj)
413 struct page *page = virt_to_head_page(obj);
415 VM_BUG_ON(!PageSlab(page));
416 return page->slab_page;
419 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
422 return slab->s_mem + cache->size * idx;
426 * We want to avoid an expensive divide : (offset / cache->size)
427 * Using the fact that size is a constant for a particular cache,
428 * we can replace (offset / cache->size) by
429 * reciprocal_divide(offset, cache->reciprocal_buffer_size)
431 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
432 const struct slab *slab, void *obj)
434 u32 offset = (obj - slab->s_mem);
435 return reciprocal_divide(offset, cache->reciprocal_buffer_size);
438 static struct arraycache_init initarray_generic =
439 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
441 /* internal cache of cache description objs */
442 static struct kmem_cache kmem_cache_boot = {
444 .limit = BOOT_CPUCACHE_ENTRIES,
446 .size = sizeof(struct kmem_cache),
447 .name = "kmem_cache",
450 #define BAD_ALIEN_MAGIC 0x01020304ul
452 #ifdef CONFIG_LOCKDEP
455 * Slab sometimes uses the kmalloc slabs to store the slab headers
456 * for other slabs "off slab".
457 * The locking for this is tricky in that it nests within the locks
458 * of all other slabs in a few places; to deal with this special
459 * locking we put on-slab caches into a separate lock-class.
461 * We set lock class for alien array caches which are up during init.
462 * The lock annotation will be lost if all cpus of a node goes down and
463 * then comes back up during hotplug
465 static struct lock_class_key on_slab_l3_key;
466 static struct lock_class_key on_slab_alc_key;
468 static struct lock_class_key debugobj_l3_key;
469 static struct lock_class_key debugobj_alc_key;
471 static void slab_set_lock_classes(struct kmem_cache *cachep,
472 struct lock_class_key *l3_key, struct lock_class_key *alc_key,
475 struct array_cache **alc;
476 struct kmem_cache_node *n;
483 lockdep_set_class(&n->list_lock, l3_key);
486 * FIXME: This check for BAD_ALIEN_MAGIC
487 * should go away when common slab code is taught to
488 * work even without alien caches.
489 * Currently, non NUMA code returns BAD_ALIEN_MAGIC
490 * for alloc_alien_cache,
492 if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
496 lockdep_set_class(&alc[r]->lock, alc_key);
500 static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
502 slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node);
505 static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
509 for_each_online_node(node)
510 slab_set_debugobj_lock_classes_node(cachep, node);
513 static void init_node_lock_keys(int q)
520 for (i = 1; i <= KMALLOC_SHIFT_HIGH; i++) {
521 struct kmem_cache_node *n;
522 struct kmem_cache *cache = kmalloc_caches[i];
528 if (!n || OFF_SLAB(cache))
531 slab_set_lock_classes(cache, &on_slab_l3_key,
532 &on_slab_alc_key, q);
536 static void on_slab_lock_classes_node(struct kmem_cache *cachep, int q)
538 if (!cachep->node[q])
541 slab_set_lock_classes(cachep, &on_slab_l3_key,
542 &on_slab_alc_key, q);
545 static inline void on_slab_lock_classes(struct kmem_cache *cachep)
549 VM_BUG_ON(OFF_SLAB(cachep));
551 on_slab_lock_classes_node(cachep, node);
554 static inline void init_lock_keys(void)
559 init_node_lock_keys(node);
562 static void init_node_lock_keys(int q)
566 static inline void init_lock_keys(void)
570 static inline void on_slab_lock_classes(struct kmem_cache *cachep)
574 static inline void on_slab_lock_classes_node(struct kmem_cache *cachep, int node)
578 static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
582 static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
587 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
589 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
591 return cachep->array[smp_processor_id()];
594 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
596 return ALIGN(sizeof(struct slab)+nr_objs*sizeof(unsigned int), align);
600 * Calculate the number of objects and left-over bytes for a given buffer size.
602 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
603 size_t align, int flags, size_t *left_over,
608 size_t slab_size = PAGE_SIZE << gfporder;
611 * The slab management structure can be either off the slab or
612 * on it. For the latter case, the memory allocated for a
616 * - One unsigned int for each object
617 * - Padding to respect alignment of @align
618 * - @buffer_size bytes for each object
620 * If the slab management structure is off the slab, then the
621 * alignment will already be calculated into the size. Because
622 * the slabs are all pages aligned, the objects will be at the
623 * correct alignment when allocated.
625 if (flags & CFLGS_OFF_SLAB) {
627 nr_objs = slab_size / buffer_size;
629 if (nr_objs > SLAB_LIMIT)
630 nr_objs = SLAB_LIMIT;
633 * Ignore padding for the initial guess. The padding
634 * is at most @align-1 bytes, and @buffer_size is at
635 * least @align. In the worst case, this result will
636 * be one greater than the number of objects that fit
637 * into the memory allocation when taking the padding
640 nr_objs = (slab_size - sizeof(struct slab)) /
641 (buffer_size + sizeof(unsigned int));
644 * This calculated number will be either the right
645 * amount, or one greater than what we want.
647 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
651 if (nr_objs > SLAB_LIMIT)
652 nr_objs = SLAB_LIMIT;
654 mgmt_size = slab_mgmt_size(nr_objs, align);
657 *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
661 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
663 static void __slab_error(const char *function, struct kmem_cache *cachep,
666 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
667 function, cachep->name, msg);
669 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
674 * By default on NUMA we use alien caches to stage the freeing of
675 * objects allocated from other nodes. This causes massive memory
676 * inefficiencies when using fake NUMA setup to split memory into a
677 * large number of small nodes, so it can be disabled on the command
681 static int use_alien_caches __read_mostly = 1;
682 static int __init noaliencache_setup(char *s)
684 use_alien_caches = 0;
687 __setup("noaliencache", noaliencache_setup);
689 static int __init slab_max_order_setup(char *str)
691 get_option(&str, &slab_max_order);
692 slab_max_order = slab_max_order < 0 ? 0 :
693 min(slab_max_order, MAX_ORDER - 1);
694 slab_max_order_set = true;
698 __setup("slab_max_order=", slab_max_order_setup);
702 * Special reaping functions for NUMA systems called from cache_reap().
703 * These take care of doing round robin flushing of alien caches (containing
704 * objects freed on different nodes from which they were allocated) and the
705 * flushing of remote pcps by calling drain_node_pages.
707 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
709 static void init_reap_node(int cpu)
713 node = next_node(cpu_to_mem(cpu), node_online_map);
714 if (node == MAX_NUMNODES)
715 node = first_node(node_online_map);
717 per_cpu(slab_reap_node, cpu) = node;
720 static void next_reap_node(void)
722 int node = __this_cpu_read(slab_reap_node);
724 node = next_node(node, node_online_map);
725 if (unlikely(node >= MAX_NUMNODES))
726 node = first_node(node_online_map);
727 __this_cpu_write(slab_reap_node, node);
731 #define init_reap_node(cpu) do { } while (0)
732 #define next_reap_node(void) do { } while (0)
736 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
737 * via the workqueue/eventd.
738 * Add the CPU number into the expiration time to minimize the possibility of
739 * the CPUs getting into lockstep and contending for the global cache chain
742 static void start_cpu_timer(int cpu)
744 struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
747 * When this gets called from do_initcalls via cpucache_init(),
748 * init_workqueues() has already run, so keventd will be setup
751 if (keventd_up() && reap_work->work.func == NULL) {
753 INIT_DEFERRABLE_WORK(reap_work, cache_reap);
754 schedule_delayed_work_on(cpu, reap_work,
755 __round_jiffies_relative(HZ, cpu));
759 static struct array_cache *alloc_arraycache(int node, int entries,
760 int batchcount, gfp_t gfp)
762 int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
763 struct array_cache *nc = NULL;
765 nc = kmalloc_node(memsize, gfp, node);
767 * The array_cache structures contain pointers to free object.
768 * However, when such objects are allocated or transferred to another
769 * cache the pointers are not cleared and they could be counted as
770 * valid references during a kmemleak scan. Therefore, kmemleak must
771 * not scan such objects.
773 kmemleak_no_scan(nc);
777 nc->batchcount = batchcount;
779 spin_lock_init(&nc->lock);
784 static inline bool is_slab_pfmemalloc(struct slab *slabp)
786 struct page *page = virt_to_page(slabp->s_mem);
788 return PageSlabPfmemalloc(page);
791 /* Clears pfmemalloc_active if no slabs have pfmalloc set */
792 static void recheck_pfmemalloc_active(struct kmem_cache *cachep,
793 struct array_cache *ac)
795 struct kmem_cache_node *n = cachep->node[numa_mem_id()];
799 if (!pfmemalloc_active)
802 spin_lock_irqsave(&n->list_lock, flags);
803 list_for_each_entry(slabp, &n->slabs_full, list)
804 if (is_slab_pfmemalloc(slabp))
807 list_for_each_entry(slabp, &n->slabs_partial, list)
808 if (is_slab_pfmemalloc(slabp))
811 list_for_each_entry(slabp, &n->slabs_free, list)
812 if (is_slab_pfmemalloc(slabp))
815 pfmemalloc_active = false;
817 spin_unlock_irqrestore(&n->list_lock, flags);
820 static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
821 gfp_t flags, bool force_refill)
824 void *objp = ac->entry[--ac->avail];
826 /* Ensure the caller is allowed to use objects from PFMEMALLOC slab */
827 if (unlikely(is_obj_pfmemalloc(objp))) {
828 struct kmem_cache_node *n;
830 if (gfp_pfmemalloc_allowed(flags)) {
831 clear_obj_pfmemalloc(&objp);
835 /* The caller cannot use PFMEMALLOC objects, find another one */
836 for (i = 0; i < ac->avail; i++) {
837 /* If a !PFMEMALLOC object is found, swap them */
838 if (!is_obj_pfmemalloc(ac->entry[i])) {
840 ac->entry[i] = ac->entry[ac->avail];
841 ac->entry[ac->avail] = objp;
847 * If there are empty slabs on the slabs_free list and we are
848 * being forced to refill the cache, mark this one !pfmemalloc.
850 n = cachep->node[numa_mem_id()];
851 if (!list_empty(&n->slabs_free) && force_refill) {
852 struct slab *slabp = virt_to_slab(objp);
853 ClearPageSlabPfmemalloc(virt_to_head_page(slabp->s_mem));
854 clear_obj_pfmemalloc(&objp);
855 recheck_pfmemalloc_active(cachep, ac);
859 /* No !PFMEMALLOC objects available */
867 static inline void *ac_get_obj(struct kmem_cache *cachep,
868 struct array_cache *ac, gfp_t flags, bool force_refill)
872 if (unlikely(sk_memalloc_socks()))
873 objp = __ac_get_obj(cachep, ac, flags, force_refill);
875 objp = ac->entry[--ac->avail];
880 static void *__ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
883 if (unlikely(pfmemalloc_active)) {
884 /* Some pfmemalloc slabs exist, check if this is one */
885 struct slab *slabp = virt_to_slab(objp);
886 struct page *page = virt_to_head_page(slabp->s_mem);
887 if (PageSlabPfmemalloc(page))
888 set_obj_pfmemalloc(&objp);
894 static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
897 if (unlikely(sk_memalloc_socks()))
898 objp = __ac_put_obj(cachep, ac, objp);
900 ac->entry[ac->avail++] = objp;
904 * Transfer objects in one arraycache to another.
905 * Locking must be handled by the caller.
907 * Return the number of entries transferred.
909 static int transfer_objects(struct array_cache *to,
910 struct array_cache *from, unsigned int max)
912 /* Figure out how many entries to transfer */
913 int nr = min3(from->avail, max, to->limit - to->avail);
918 memcpy(to->entry + to->avail, from->entry + from->avail -nr,
928 #define drain_alien_cache(cachep, alien) do { } while (0)
929 #define reap_alien(cachep, n) do { } while (0)
931 static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
933 return (struct array_cache **)BAD_ALIEN_MAGIC;
936 static inline void free_alien_cache(struct array_cache **ac_ptr)
940 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
945 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
951 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
952 gfp_t flags, int nodeid)
957 #else /* CONFIG_NUMA */
959 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
960 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
962 static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
964 struct array_cache **ac_ptr;
965 int memsize = sizeof(void *) * nr_node_ids;
970 ac_ptr = kzalloc_node(memsize, gfp, node);
973 if (i == node || !node_online(i))
975 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
977 for (i--; i >= 0; i--)
987 static void free_alien_cache(struct array_cache **ac_ptr)
998 static void __drain_alien_cache(struct kmem_cache *cachep,
999 struct array_cache *ac, int node)
1001 struct kmem_cache_node *n = cachep->node[node];
1004 spin_lock(&n->list_lock);
1006 * Stuff objects into the remote nodes shared array first.
1007 * That way we could avoid the overhead of putting the objects
1008 * into the free lists and getting them back later.
1011 transfer_objects(n->shared, ac, ac->limit);
1013 free_block(cachep, ac->entry, ac->avail, node);
1015 spin_unlock(&n->list_lock);
1020 * Called from cache_reap() to regularly drain alien caches round robin.
1022 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
1024 int node = __this_cpu_read(slab_reap_node);
1027 struct array_cache *ac = n->alien[node];
1029 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1030 __drain_alien_cache(cachep, ac, node);
1031 spin_unlock_irq(&ac->lock);
1036 static void drain_alien_cache(struct kmem_cache *cachep,
1037 struct array_cache **alien)
1040 struct array_cache *ac;
1041 unsigned long flags;
1043 for_each_online_node(i) {
1046 spin_lock_irqsave(&ac->lock, flags);
1047 __drain_alien_cache(cachep, ac, i);
1048 spin_unlock_irqrestore(&ac->lock, flags);
1053 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1055 int nodeid = page_to_nid(virt_to_page(objp));
1056 struct kmem_cache_node *n;
1057 struct array_cache *alien = NULL;
1060 node = numa_mem_id();
1063 * Make sure we are not freeing a object from another node to the array
1064 * cache on this cpu.
1066 if (likely(nodeid == node))
1069 n = cachep->node[node];
1070 STATS_INC_NODEFREES(cachep);
1071 if (n->alien && n->alien[nodeid]) {
1072 alien = n->alien[nodeid];
1073 spin_lock(&alien->lock);
1074 if (unlikely(alien->avail == alien->limit)) {
1075 STATS_INC_ACOVERFLOW(cachep);
1076 __drain_alien_cache(cachep, alien, nodeid);
1078 ac_put_obj(cachep, alien, objp);
1079 spin_unlock(&alien->lock);
1081 spin_lock(&(cachep->node[nodeid])->list_lock);
1082 free_block(cachep, &objp, 1, nodeid);
1083 spin_unlock(&(cachep->node[nodeid])->list_lock);
1090 * Allocates and initializes node for a node on each slab cache, used for
1091 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node
1092 * will be allocated off-node since memory is not yet online for the new node.
1093 * When hotplugging memory or a cpu, existing node are not replaced if
1096 * Must hold slab_mutex.
1098 static int init_cache_node_node(int node)
1100 struct kmem_cache *cachep;
1101 struct kmem_cache_node *n;
1102 const int memsize = sizeof(struct kmem_cache_node);
1104 list_for_each_entry(cachep, &slab_caches, list) {
1106 * Set up the size64 kmemlist for cpu before we can
1107 * begin anything. Make sure some other cpu on this
1108 * node has not already allocated this
1110 if (!cachep->node[node]) {
1111 n = kmalloc_node(memsize, GFP_KERNEL, node);
1114 kmem_cache_node_init(n);
1115 n->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1116 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1119 * The l3s don't come and go as CPUs come and
1120 * go. slab_mutex is sufficient
1123 cachep->node[node] = n;
1126 spin_lock_irq(&cachep->node[node]->list_lock);
1127 cachep->node[node]->free_limit =
1128 (1 + nr_cpus_node(node)) *
1129 cachep->batchcount + cachep->num;
1130 spin_unlock_irq(&cachep->node[node]->list_lock);
1135 static inline int slabs_tofree(struct kmem_cache *cachep,
1136 struct kmem_cache_node *n)
1138 return (n->free_objects + cachep->num - 1) / cachep->num;
1141 static void cpuup_canceled(long cpu)
1143 struct kmem_cache *cachep;
1144 struct kmem_cache_node *n = NULL;
1145 int node = cpu_to_mem(cpu);
1146 const struct cpumask *mask = cpumask_of_node(node);
1148 list_for_each_entry(cachep, &slab_caches, list) {
1149 struct array_cache *nc;
1150 struct array_cache *shared;
1151 struct array_cache **alien;
1153 /* cpu is dead; no one can alloc from it. */
1154 nc = cachep->array[cpu];
1155 cachep->array[cpu] = NULL;
1156 n = cachep->node[node];
1159 goto free_array_cache;
1161 spin_lock_irq(&n->list_lock);
1163 /* Free limit for this kmem_cache_node */
1164 n->free_limit -= cachep->batchcount;
1166 free_block(cachep, nc->entry, nc->avail, node);
1168 if (!cpumask_empty(mask)) {
1169 spin_unlock_irq(&n->list_lock);
1170 goto free_array_cache;
1175 free_block(cachep, shared->entry,
1176 shared->avail, node);
1183 spin_unlock_irq(&n->list_lock);
1187 drain_alien_cache(cachep, alien);
1188 free_alien_cache(alien);
1194 * In the previous loop, all the objects were freed to
1195 * the respective cache's slabs, now we can go ahead and
1196 * shrink each nodelist to its limit.
1198 list_for_each_entry(cachep, &slab_caches, list) {
1199 n = cachep->node[node];
1202 drain_freelist(cachep, n, slabs_tofree(cachep, n));
1206 static int cpuup_prepare(long cpu)
1208 struct kmem_cache *cachep;
1209 struct kmem_cache_node *n = NULL;
1210 int node = cpu_to_mem(cpu);
1214 * We need to do this right in the beginning since
1215 * alloc_arraycache's are going to use this list.
1216 * kmalloc_node allows us to add the slab to the right
1217 * kmem_cache_node and not this cpu's kmem_cache_node
1219 err = init_cache_node_node(node);
1224 * Now we can go ahead with allocating the shared arrays and
1227 list_for_each_entry(cachep, &slab_caches, list) {
1228 struct array_cache *nc;
1229 struct array_cache *shared = NULL;
1230 struct array_cache **alien = NULL;
1232 nc = alloc_arraycache(node, cachep->limit,
1233 cachep->batchcount, GFP_KERNEL);
1236 if (cachep->shared) {
1237 shared = alloc_arraycache(node,
1238 cachep->shared * cachep->batchcount,
1239 0xbaadf00d, GFP_KERNEL);
1245 if (use_alien_caches) {
1246 alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
1253 cachep->array[cpu] = nc;
1254 n = cachep->node[node];
1257 spin_lock_irq(&n->list_lock);
1260 * We are serialised from CPU_DEAD or
1261 * CPU_UP_CANCELLED by the cpucontrol lock
1272 spin_unlock_irq(&n->list_lock);
1274 free_alien_cache(alien);
1275 if (cachep->flags & SLAB_DEBUG_OBJECTS)
1276 slab_set_debugobj_lock_classes_node(cachep, node);
1277 else if (!OFF_SLAB(cachep) &&
1278 !(cachep->flags & SLAB_DESTROY_BY_RCU))
1279 on_slab_lock_classes_node(cachep, node);
1281 init_node_lock_keys(node);
1285 cpuup_canceled(cpu);
1289 static int cpuup_callback(struct notifier_block *nfb,
1290 unsigned long action, void *hcpu)
1292 long cpu = (long)hcpu;
1296 case CPU_UP_PREPARE:
1297 case CPU_UP_PREPARE_FROZEN:
1298 mutex_lock(&slab_mutex);
1299 err = cpuup_prepare(cpu);
1300 mutex_unlock(&slab_mutex);
1303 case CPU_ONLINE_FROZEN:
1304 start_cpu_timer(cpu);
1306 #ifdef CONFIG_HOTPLUG_CPU
1307 case CPU_DOWN_PREPARE:
1308 case CPU_DOWN_PREPARE_FROZEN:
1310 * Shutdown cache reaper. Note that the slab_mutex is
1311 * held so that if cache_reap() is invoked it cannot do
1312 * anything expensive but will only modify reap_work
1313 * and reschedule the timer.
1315 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
1316 /* Now the cache_reaper is guaranteed to be not running. */
1317 per_cpu(slab_reap_work, cpu).work.func = NULL;
1319 case CPU_DOWN_FAILED:
1320 case CPU_DOWN_FAILED_FROZEN:
1321 start_cpu_timer(cpu);
1324 case CPU_DEAD_FROZEN:
1326 * Even if all the cpus of a node are down, we don't free the
1327 * kmem_cache_node of any cache. This to avoid a race between
1328 * cpu_down, and a kmalloc allocation from another cpu for
1329 * memory from the node of the cpu going down. The node
1330 * structure is usually allocated from kmem_cache_create() and
1331 * gets destroyed at kmem_cache_destroy().
1335 case CPU_UP_CANCELED:
1336 case CPU_UP_CANCELED_FROZEN:
1337 mutex_lock(&slab_mutex);
1338 cpuup_canceled(cpu);
1339 mutex_unlock(&slab_mutex);
1342 return notifier_from_errno(err);
1345 static struct notifier_block cpucache_notifier = {
1346 &cpuup_callback, NULL, 0
1349 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1351 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1352 * Returns -EBUSY if all objects cannot be drained so that the node is not
1355 * Must hold slab_mutex.
1357 static int __meminit drain_cache_node_node(int node)
1359 struct kmem_cache *cachep;
1362 list_for_each_entry(cachep, &slab_caches, list) {
1363 struct kmem_cache_node *n;
1365 n = cachep->node[node];
1369 drain_freelist(cachep, n, slabs_tofree(cachep, n));
1371 if (!list_empty(&n->slabs_full) ||
1372 !list_empty(&n->slabs_partial)) {
1380 static int __meminit slab_memory_callback(struct notifier_block *self,
1381 unsigned long action, void *arg)
1383 struct memory_notify *mnb = arg;
1387 nid = mnb->status_change_nid;
1392 case MEM_GOING_ONLINE:
1393 mutex_lock(&slab_mutex);
1394 ret = init_cache_node_node(nid);
1395 mutex_unlock(&slab_mutex);
1397 case MEM_GOING_OFFLINE:
1398 mutex_lock(&slab_mutex);
1399 ret = drain_cache_node_node(nid);
1400 mutex_unlock(&slab_mutex);
1404 case MEM_CANCEL_ONLINE:
1405 case MEM_CANCEL_OFFLINE:
1409 return notifier_from_errno(ret);
1411 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1414 * swap the static kmem_cache_node with kmalloced memory
1416 static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list,
1419 struct kmem_cache_node *ptr;
1421 ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid);
1424 memcpy(ptr, list, sizeof(struct kmem_cache_node));
1426 * Do not assume that spinlocks can be initialized via memcpy:
1428 spin_lock_init(&ptr->list_lock);
1430 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1431 cachep->node[nodeid] = ptr;
1435 * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1436 * size of kmem_cache_node.
1438 static void __init set_up_node(struct kmem_cache *cachep, int index)
1442 for_each_online_node(node) {
1443 cachep->node[node] = &init_kmem_cache_node[index + node];
1444 cachep->node[node]->next_reap = jiffies +
1446 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1451 * The memory after the last cpu cache pointer is used for the
1454 static void setup_node_pointer(struct kmem_cache *cachep)
1456 cachep->node = (struct kmem_cache_node **)&cachep->array[nr_cpu_ids];
1460 * Initialisation. Called after the page allocator have been initialised and
1461 * before smp_init().
1463 void __init kmem_cache_init(void)
1467 BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) <
1468 sizeof(struct rcu_head));
1469 kmem_cache = &kmem_cache_boot;
1470 setup_node_pointer(kmem_cache);
1472 if (num_possible_nodes() == 1)
1473 use_alien_caches = 0;
1475 for (i = 0; i < NUM_INIT_LISTS; i++)
1476 kmem_cache_node_init(&init_kmem_cache_node[i]);
1478 set_up_node(kmem_cache, CACHE_CACHE);
1481 * Fragmentation resistance on low memory - only use bigger
1482 * page orders on machines with more than 32MB of memory if
1483 * not overridden on the command line.
1485 if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
1486 slab_max_order = SLAB_MAX_ORDER_HI;
1488 /* Bootstrap is tricky, because several objects are allocated
1489 * from caches that do not exist yet:
1490 * 1) initialize the kmem_cache cache: it contains the struct
1491 * kmem_cache structures of all caches, except kmem_cache itself:
1492 * kmem_cache is statically allocated.
1493 * Initially an __init data area is used for the head array and the
1494 * kmem_cache_node structures, it's replaced with a kmalloc allocated
1495 * array at the end of the bootstrap.
1496 * 2) Create the first kmalloc cache.
1497 * The struct kmem_cache for the new cache is allocated normally.
1498 * An __init data area is used for the head array.
1499 * 3) Create the remaining kmalloc caches, with minimally sized
1501 * 4) Replace the __init data head arrays for kmem_cache and the first
1502 * kmalloc cache with kmalloc allocated arrays.
1503 * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1504 * the other cache's with kmalloc allocated memory.
1505 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1508 /* 1) create the kmem_cache */
1511 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1513 create_boot_cache(kmem_cache, "kmem_cache",
1514 offsetof(struct kmem_cache, array[nr_cpu_ids]) +
1515 nr_node_ids * sizeof(struct kmem_cache_node *),
1516 SLAB_HWCACHE_ALIGN);
1517 list_add(&kmem_cache->list, &slab_caches);
1519 /* 2+3) create the kmalloc caches */
1522 * Initialize the caches that provide memory for the array cache and the
1523 * kmem_cache_node structures first. Without this, further allocations will
1527 kmalloc_caches[INDEX_AC] = create_kmalloc_cache("kmalloc-ac",
1528 kmalloc_size(INDEX_AC), ARCH_KMALLOC_FLAGS);
1530 if (INDEX_AC != INDEX_NODE)
1531 kmalloc_caches[INDEX_NODE] =
1532 create_kmalloc_cache("kmalloc-node",
1533 kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS);
1535 slab_early_init = 0;
1537 /* 4) Replace the bootstrap head arrays */
1539 struct array_cache *ptr;
1541 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1543 memcpy(ptr, cpu_cache_get(kmem_cache),
1544 sizeof(struct arraycache_init));
1546 * Do not assume that spinlocks can be initialized via memcpy:
1548 spin_lock_init(&ptr->lock);
1550 kmem_cache->array[smp_processor_id()] = ptr;
1552 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1554 BUG_ON(cpu_cache_get(kmalloc_caches[INDEX_AC])
1555 != &initarray_generic.cache);
1556 memcpy(ptr, cpu_cache_get(kmalloc_caches[INDEX_AC]),
1557 sizeof(struct arraycache_init));
1559 * Do not assume that spinlocks can be initialized via memcpy:
1561 spin_lock_init(&ptr->lock);
1563 kmalloc_caches[INDEX_AC]->array[smp_processor_id()] = ptr;
1565 /* 5) Replace the bootstrap kmem_cache_node */
1569 for_each_online_node(nid) {
1570 init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid);
1572 init_list(kmalloc_caches[INDEX_AC],
1573 &init_kmem_cache_node[SIZE_AC + nid], nid);
1575 if (INDEX_AC != INDEX_NODE) {
1576 init_list(kmalloc_caches[INDEX_NODE],
1577 &init_kmem_cache_node[SIZE_NODE + nid], nid);
1582 create_kmalloc_caches(ARCH_KMALLOC_FLAGS);
1585 void __init kmem_cache_init_late(void)
1587 struct kmem_cache *cachep;
1591 /* 6) resize the head arrays to their final sizes */
1592 mutex_lock(&slab_mutex);
1593 list_for_each_entry(cachep, &slab_caches, list)
1594 if (enable_cpucache(cachep, GFP_NOWAIT))
1596 mutex_unlock(&slab_mutex);
1598 /* Annotate slab for lockdep -- annotate the malloc caches */
1605 * Register a cpu startup notifier callback that initializes
1606 * cpu_cache_get for all new cpus
1608 register_cpu_notifier(&cpucache_notifier);
1612 * Register a memory hotplug callback that initializes and frees
1615 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
1619 * The reap timers are started later, with a module init call: That part
1620 * of the kernel is not yet operational.
1624 static int __init cpucache_init(void)
1629 * Register the timers that return unneeded pages to the page allocator
1631 for_each_online_cpu(cpu)
1632 start_cpu_timer(cpu);
1638 __initcall(cpucache_init);
1640 static noinline void
1641 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
1643 struct kmem_cache_node *n;
1645 unsigned long flags;
1649 "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1651 printk(KERN_WARNING " cache: %s, object size: %d, order: %d\n",
1652 cachep->name, cachep->size, cachep->gfporder);
1654 for_each_online_node(node) {
1655 unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
1656 unsigned long active_slabs = 0, num_slabs = 0;
1658 n = cachep->node[node];
1662 spin_lock_irqsave(&n->list_lock, flags);
1663 list_for_each_entry(slabp, &n->slabs_full, list) {
1664 active_objs += cachep->num;
1667 list_for_each_entry(slabp, &n->slabs_partial, list) {
1668 active_objs += slabp->inuse;
1671 list_for_each_entry(slabp, &n->slabs_free, list)
1674 free_objects += n->free_objects;
1675 spin_unlock_irqrestore(&n->list_lock, flags);
1677 num_slabs += active_slabs;
1678 num_objs = num_slabs * cachep->num;
1680 " node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
1681 node, active_slabs, num_slabs, active_objs, num_objs,
1687 * Interface to system's page allocator. No need to hold the cache-lock.
1689 * If we requested dmaable memory, we will get it. Even if we
1690 * did not request dmaable memory, we might get it, but that
1691 * would be relatively rare and ignorable.
1693 static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
1699 flags |= cachep->allocflags;
1700 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1701 flags |= __GFP_RECLAIMABLE;
1703 page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1705 if (!(flags & __GFP_NOWARN) && printk_ratelimit())
1706 slab_out_of_memory(cachep, flags, nodeid);
1710 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1711 if (unlikely(page->pfmemalloc))
1712 pfmemalloc_active = true;
1714 nr_pages = (1 << cachep->gfporder);
1715 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1716 add_zone_page_state(page_zone(page),
1717 NR_SLAB_RECLAIMABLE, nr_pages);
1719 add_zone_page_state(page_zone(page),
1720 NR_SLAB_UNRECLAIMABLE, nr_pages);
1721 __SetPageSlab(page);
1722 if (page->pfmemalloc)
1723 SetPageSlabPfmemalloc(page);
1724 memcg_bind_pages(cachep, cachep->gfporder);
1726 if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1727 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1730 kmemcheck_mark_uninitialized_pages(page, nr_pages);
1732 kmemcheck_mark_unallocated_pages(page, nr_pages);
1739 * Interface to system's page release.
1741 static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
1743 const unsigned long nr_freed = (1 << cachep->gfporder);
1745 kmemcheck_free_shadow(page, cachep->gfporder);
1747 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1748 sub_zone_page_state(page_zone(page),
1749 NR_SLAB_RECLAIMABLE, nr_freed);
1751 sub_zone_page_state(page_zone(page),
1752 NR_SLAB_UNRECLAIMABLE, nr_freed);
1754 BUG_ON(!PageSlab(page));
1755 __ClearPageSlabPfmemalloc(page);
1756 __ClearPageSlab(page);
1758 memcg_release_pages(cachep, cachep->gfporder);
1759 if (current->reclaim_state)
1760 current->reclaim_state->reclaimed_slab += nr_freed;
1761 __free_memcg_kmem_pages(page, cachep->gfporder);
1764 static void kmem_rcu_free(struct rcu_head *head)
1766 struct kmem_cache *cachep;
1769 page = container_of(head, struct page, rcu_head);
1770 cachep = page->slab_cache;
1772 kmem_freepages(cachep, page);
1777 #ifdef CONFIG_DEBUG_PAGEALLOC
1778 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1779 unsigned long caller)
1781 int size = cachep->object_size;
1783 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1785 if (size < 5 * sizeof(unsigned long))
1788 *addr++ = 0x12345678;
1790 *addr++ = smp_processor_id();
1791 size -= 3 * sizeof(unsigned long);
1793 unsigned long *sptr = &caller;
1794 unsigned long svalue;
1796 while (!kstack_end(sptr)) {
1798 if (kernel_text_address(svalue)) {
1800 size -= sizeof(unsigned long);
1801 if (size <= sizeof(unsigned long))
1807 *addr++ = 0x87654321;
1811 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1813 int size = cachep->object_size;
1814 addr = &((char *)addr)[obj_offset(cachep)];
1816 memset(addr, val, size);
1817 *(unsigned char *)(addr + size - 1) = POISON_END;
1820 static void dump_line(char *data, int offset, int limit)
1823 unsigned char error = 0;
1826 printk(KERN_ERR "%03x: ", offset);
1827 for (i = 0; i < limit; i++) {
1828 if (data[offset + i] != POISON_FREE) {
1829 error = data[offset + i];
1833 print_hex_dump(KERN_CONT, "", 0, 16, 1,
1834 &data[offset], limit, 1);
1836 if (bad_count == 1) {
1837 error ^= POISON_FREE;
1838 if (!(error & (error - 1))) {
1839 printk(KERN_ERR "Single bit error detected. Probably "
1842 printk(KERN_ERR "Run memtest86+ or a similar memory "
1845 printk(KERN_ERR "Run a memory test tool.\n");
1854 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1859 if (cachep->flags & SLAB_RED_ZONE) {
1860 printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n",
1861 *dbg_redzone1(cachep, objp),
1862 *dbg_redzone2(cachep, objp));
1865 if (cachep->flags & SLAB_STORE_USER) {
1866 printk(KERN_ERR "Last user: [<%p>](%pSR)\n",
1867 *dbg_userword(cachep, objp),
1868 *dbg_userword(cachep, objp));
1870 realobj = (char *)objp + obj_offset(cachep);
1871 size = cachep->object_size;
1872 for (i = 0; i < size && lines; i += 16, lines--) {
1875 if (i + limit > size)
1877 dump_line(realobj, i, limit);
1881 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1887 realobj = (char *)objp + obj_offset(cachep);
1888 size = cachep->object_size;
1890 for (i = 0; i < size; i++) {
1891 char exp = POISON_FREE;
1894 if (realobj[i] != exp) {
1900 "Slab corruption (%s): %s start=%p, len=%d\n",
1901 print_tainted(), cachep->name, realobj, size);
1902 print_objinfo(cachep, objp, 0);
1904 /* Hexdump the affected line */
1907 if (i + limit > size)
1909 dump_line(realobj, i, limit);
1912 /* Limit to 5 lines */
1918 /* Print some data about the neighboring objects, if they
1921 struct slab *slabp = virt_to_slab(objp);
1924 objnr = obj_to_index(cachep, slabp, objp);
1926 objp = index_to_obj(cachep, slabp, objnr - 1);
1927 realobj = (char *)objp + obj_offset(cachep);
1928 printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1930 print_objinfo(cachep, objp, 2);
1932 if (objnr + 1 < cachep->num) {
1933 objp = index_to_obj(cachep, slabp, objnr + 1);
1934 realobj = (char *)objp + obj_offset(cachep);
1935 printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1937 print_objinfo(cachep, objp, 2);
1944 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
1947 for (i = 0; i < cachep->num; i++) {
1948 void *objp = index_to_obj(cachep, slabp, i);
1950 if (cachep->flags & SLAB_POISON) {
1951 #ifdef CONFIG_DEBUG_PAGEALLOC
1952 if (cachep->size % PAGE_SIZE == 0 &&
1954 kernel_map_pages(virt_to_page(objp),
1955 cachep->size / PAGE_SIZE, 1);
1957 check_poison_obj(cachep, objp);
1959 check_poison_obj(cachep, objp);
1962 if (cachep->flags & SLAB_RED_ZONE) {
1963 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1964 slab_error(cachep, "start of a freed object "
1966 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1967 slab_error(cachep, "end of a freed object "
1973 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
1979 * slab_destroy - destroy and release all objects in a slab
1980 * @cachep: cache pointer being destroyed
1981 * @slabp: slab pointer being destroyed
1983 * Destroy all the objs in a slab, and release the mem back to the system.
1984 * Before calling the slab must have been unlinked from the cache. The
1985 * cache-lock is not held/needed.
1987 static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
1989 struct page *page = virt_to_head_page(slabp->s_mem);
1991 slab_destroy_debugcheck(cachep, slabp);
1992 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
1993 struct rcu_head *head;
1996 * RCU free overloads the RCU head over the LRU.
1997 * slab_page has been overloeaded over the LRU,
1998 * however it is not used from now on so that
1999 * we can use it safely.
2001 head = (void *)&page->rcu_head;
2002 call_rcu(head, kmem_rcu_free);
2005 kmem_freepages(cachep, page);
2009 * From now on, we don't use slab management
2010 * although actual page can be freed in rcu context
2012 if (OFF_SLAB(cachep))
2013 kmem_cache_free(cachep->slabp_cache, slabp);
2017 * calculate_slab_order - calculate size (page order) of slabs
2018 * @cachep: pointer to the cache that is being created
2019 * @size: size of objects to be created in this cache.
2020 * @align: required alignment for the objects.
2021 * @flags: slab allocation flags
2023 * Also calculates the number of objects per slab.
2025 * This could be made much more intelligent. For now, try to avoid using
2026 * high order pages for slabs. When the gfp() functions are more friendly
2027 * towards high-order requests, this should be changed.
2029 static size_t calculate_slab_order(struct kmem_cache *cachep,
2030 size_t size, size_t align, unsigned long flags)
2032 unsigned long offslab_limit;
2033 size_t left_over = 0;
2036 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
2040 cache_estimate(gfporder, size, align, flags, &remainder, &num);
2044 if (flags & CFLGS_OFF_SLAB) {
2046 * Max number of objs-per-slab for caches which
2047 * use off-slab slabs. Needed to avoid a possible
2048 * looping condition in cache_grow().
2050 offslab_limit = size - sizeof(struct slab);
2051 offslab_limit /= sizeof(unsigned int);
2053 if (num > offslab_limit)
2057 /* Found something acceptable - save it away */
2059 cachep->gfporder = gfporder;
2060 left_over = remainder;
2063 * A VFS-reclaimable slab tends to have most allocations
2064 * as GFP_NOFS and we really don't want to have to be allocating
2065 * higher-order pages when we are unable to shrink dcache.
2067 if (flags & SLAB_RECLAIM_ACCOUNT)
2071 * Large number of objects is good, but very large slabs are
2072 * currently bad for the gfp()s.
2074 if (gfporder >= slab_max_order)
2078 * Acceptable internal fragmentation?
2080 if (left_over * 8 <= (PAGE_SIZE << gfporder))
2086 static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
2088 if (slab_state >= FULL)
2089 return enable_cpucache(cachep, gfp);
2091 if (slab_state == DOWN) {
2093 * Note: Creation of first cache (kmem_cache).
2094 * The setup_node is taken care
2095 * of by the caller of __kmem_cache_create
2097 cachep->array[smp_processor_id()] = &initarray_generic.cache;
2098 slab_state = PARTIAL;
2099 } else if (slab_state == PARTIAL) {
2101 * Note: the second kmem_cache_create must create the cache
2102 * that's used by kmalloc(24), otherwise the creation of
2103 * further caches will BUG().
2105 cachep->array[smp_processor_id()] = &initarray_generic.cache;
2108 * If the cache that's used by kmalloc(sizeof(kmem_cache_node)) is
2109 * the second cache, then we need to set up all its node/,
2110 * otherwise the creation of further caches will BUG().
2112 set_up_node(cachep, SIZE_AC);
2113 if (INDEX_AC == INDEX_NODE)
2114 slab_state = PARTIAL_NODE;
2116 slab_state = PARTIAL_ARRAYCACHE;
2118 /* Remaining boot caches */
2119 cachep->array[smp_processor_id()] =
2120 kmalloc(sizeof(struct arraycache_init), gfp);
2122 if (slab_state == PARTIAL_ARRAYCACHE) {
2123 set_up_node(cachep, SIZE_NODE);
2124 slab_state = PARTIAL_NODE;
2127 for_each_online_node(node) {
2128 cachep->node[node] =
2129 kmalloc_node(sizeof(struct kmem_cache_node),
2131 BUG_ON(!cachep->node[node]);
2132 kmem_cache_node_init(cachep->node[node]);
2136 cachep->node[numa_mem_id()]->next_reap =
2137 jiffies + REAPTIMEOUT_LIST3 +
2138 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
2140 cpu_cache_get(cachep)->avail = 0;
2141 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
2142 cpu_cache_get(cachep)->batchcount = 1;
2143 cpu_cache_get(cachep)->touched = 0;
2144 cachep->batchcount = 1;
2145 cachep->limit = BOOT_CPUCACHE_ENTRIES;
2150 * __kmem_cache_create - Create a cache.
2151 * @cachep: cache management descriptor
2152 * @flags: SLAB flags
2154 * Returns a ptr to the cache on success, NULL on failure.
2155 * Cannot be called within a int, but can be interrupted.
2156 * The @ctor is run when new pages are allocated by the cache.
2160 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2161 * to catch references to uninitialised memory.
2163 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2164 * for buffer overruns.
2166 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2167 * cacheline. This can be beneficial if you're counting cycles as closely
2171 __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
2173 size_t left_over, slab_size, ralign;
2176 size_t size = cachep->size;
2181 * Enable redzoning and last user accounting, except for caches with
2182 * large objects, if the increased size would increase the object size
2183 * above the next power of two: caches with object sizes just above a
2184 * power of two have a significant amount of internal fragmentation.
2186 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2187 2 * sizeof(unsigned long long)))
2188 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2189 if (!(flags & SLAB_DESTROY_BY_RCU))
2190 flags |= SLAB_POISON;
2192 if (flags & SLAB_DESTROY_BY_RCU)
2193 BUG_ON(flags & SLAB_POISON);
2197 * Check that size is in terms of words. This is needed to avoid
2198 * unaligned accesses for some archs when redzoning is used, and makes
2199 * sure any on-slab bufctl's are also correctly aligned.
2201 if (size & (BYTES_PER_WORD - 1)) {
2202 size += (BYTES_PER_WORD - 1);
2203 size &= ~(BYTES_PER_WORD - 1);
2207 * Redzoning and user store require word alignment or possibly larger.
2208 * Note this will be overridden by architecture or caller mandated
2209 * alignment if either is greater than BYTES_PER_WORD.
2211 if (flags & SLAB_STORE_USER)
2212 ralign = BYTES_PER_WORD;
2214 if (flags & SLAB_RED_ZONE) {
2215 ralign = REDZONE_ALIGN;
2216 /* If redzoning, ensure that the second redzone is suitably
2217 * aligned, by adjusting the object size accordingly. */
2218 size += REDZONE_ALIGN - 1;
2219 size &= ~(REDZONE_ALIGN - 1);
2222 /* 3) caller mandated alignment */
2223 if (ralign < cachep->align) {
2224 ralign = cachep->align;
2226 /* disable debug if necessary */
2227 if (ralign > __alignof__(unsigned long long))
2228 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2232 cachep->align = ralign;
2234 if (slab_is_available())
2239 setup_node_pointer(cachep);
2243 * Both debugging options require word-alignment which is calculated
2246 if (flags & SLAB_RED_ZONE) {
2247 /* add space for red zone words */
2248 cachep->obj_offset += sizeof(unsigned long long);
2249 size += 2 * sizeof(unsigned long long);
2251 if (flags & SLAB_STORE_USER) {
2252 /* user store requires one word storage behind the end of
2253 * the real object. But if the second red zone needs to be
2254 * aligned to 64 bits, we must allow that much space.
2256 if (flags & SLAB_RED_ZONE)
2257 size += REDZONE_ALIGN;
2259 size += BYTES_PER_WORD;
2261 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2262 if (size >= kmalloc_size(INDEX_NODE + 1)
2263 && cachep->object_size > cache_line_size()
2264 && ALIGN(size, cachep->align) < PAGE_SIZE) {
2265 cachep->obj_offset += PAGE_SIZE - ALIGN(size, cachep->align);
2272 * Determine if the slab management is 'on' or 'off' slab.
2273 * (bootstrapping cannot cope with offslab caches so don't do
2274 * it too early on. Always use on-slab management when
2275 * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
2277 if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init &&
2278 !(flags & SLAB_NOLEAKTRACE))
2280 * Size is large, assume best to place the slab management obj
2281 * off-slab (should allow better packing of objs).
2283 flags |= CFLGS_OFF_SLAB;
2285 size = ALIGN(size, cachep->align);
2287 left_over = calculate_slab_order(cachep, size, cachep->align, flags);
2292 slab_size = ALIGN(cachep->num * sizeof(unsigned int)
2293 + sizeof(struct slab), cachep->align);
2296 * If the slab has been placed off-slab, and we have enough space then
2297 * move it on-slab. This is at the expense of any extra colouring.
2299 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
2300 flags &= ~CFLGS_OFF_SLAB;
2301 left_over -= slab_size;
2304 if (flags & CFLGS_OFF_SLAB) {
2305 /* really off slab. No need for manual alignment */
2307 cachep->num * sizeof(unsigned int) + sizeof(struct slab);
2309 #ifdef CONFIG_PAGE_POISONING
2310 /* If we're going to use the generic kernel_map_pages()
2311 * poisoning, then it's going to smash the contents of
2312 * the redzone and userword anyhow, so switch them off.
2314 if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
2315 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2319 cachep->colour_off = cache_line_size();
2320 /* Offset must be a multiple of the alignment. */
2321 if (cachep->colour_off < cachep->align)
2322 cachep->colour_off = cachep->align;
2323 cachep->colour = left_over / cachep->colour_off;
2324 cachep->slab_size = slab_size;
2325 cachep->flags = flags;
2326 cachep->allocflags = __GFP_COMP;
2327 if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
2328 cachep->allocflags |= GFP_DMA;
2329 cachep->size = size;
2330 cachep->reciprocal_buffer_size = reciprocal_value(size);
2332 if (flags & CFLGS_OFF_SLAB) {
2333 cachep->slabp_cache = kmalloc_slab(slab_size, 0u);
2335 * This is a possibility for one of the malloc_sizes caches.
2336 * But since we go off slab only for object size greater than
2337 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2338 * this should not happen at all.
2339 * But leave a BUG_ON for some lucky dude.
2341 BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
2344 err = setup_cpu_cache(cachep, gfp);
2346 __kmem_cache_shutdown(cachep);
2350 if (flags & SLAB_DEBUG_OBJECTS) {
2352 * Would deadlock through slab_destroy()->call_rcu()->
2353 * debug_object_activate()->kmem_cache_alloc().
2355 WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
2357 slab_set_debugobj_lock_classes(cachep);
2358 } else if (!OFF_SLAB(cachep) && !(flags & SLAB_DESTROY_BY_RCU))
2359 on_slab_lock_classes(cachep);
2365 static void check_irq_off(void)
2367 BUG_ON(!irqs_disabled());
2370 static void check_irq_on(void)
2372 BUG_ON(irqs_disabled());
2375 static void check_spinlock_acquired(struct kmem_cache *cachep)
2379 assert_spin_locked(&cachep->node[numa_mem_id()]->list_lock);
2383 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2387 assert_spin_locked(&cachep->node[node]->list_lock);
2392 #define check_irq_off() do { } while(0)
2393 #define check_irq_on() do { } while(0)
2394 #define check_spinlock_acquired(x) do { } while(0)
2395 #define check_spinlock_acquired_node(x, y) do { } while(0)
2398 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
2399 struct array_cache *ac,
2400 int force, int node);
2402 static void do_drain(void *arg)
2404 struct kmem_cache *cachep = arg;
2405 struct array_cache *ac;
2406 int node = numa_mem_id();
2409 ac = cpu_cache_get(cachep);
2410 spin_lock(&cachep->node[node]->list_lock);
2411 free_block(cachep, ac->entry, ac->avail, node);
2412 spin_unlock(&cachep->node[node]->list_lock);
2416 static void drain_cpu_caches(struct kmem_cache *cachep)
2418 struct kmem_cache_node *n;
2421 on_each_cpu(do_drain, cachep, 1);
2423 for_each_online_node(node) {
2424 n = cachep->node[node];
2426 drain_alien_cache(cachep, n->alien);
2429 for_each_online_node(node) {
2430 n = cachep->node[node];
2432 drain_array(cachep, n, n->shared, 1, node);
2437 * Remove slabs from the list of free slabs.
2438 * Specify the number of slabs to drain in tofree.
2440 * Returns the actual number of slabs released.
2442 static int drain_freelist(struct kmem_cache *cache,
2443 struct kmem_cache_node *n, int tofree)
2445 struct list_head *p;
2450 while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
2452 spin_lock_irq(&n->list_lock);
2453 p = n->slabs_free.prev;
2454 if (p == &n->slabs_free) {
2455 spin_unlock_irq(&n->list_lock);
2459 slabp = list_entry(p, struct slab, list);
2461 BUG_ON(slabp->inuse);
2463 list_del(&slabp->list);
2465 * Safe to drop the lock. The slab is no longer linked
2468 n->free_objects -= cache->num;
2469 spin_unlock_irq(&n->list_lock);
2470 slab_destroy(cache, slabp);
2477 /* Called with slab_mutex held to protect against cpu hotplug */
2478 static int __cache_shrink(struct kmem_cache *cachep)
2481 struct kmem_cache_node *n;
2483 drain_cpu_caches(cachep);
2486 for_each_online_node(i) {
2487 n = cachep->node[i];
2491 drain_freelist(cachep, n, slabs_tofree(cachep, n));
2493 ret += !list_empty(&n->slabs_full) ||
2494 !list_empty(&n->slabs_partial);
2496 return (ret ? 1 : 0);
2500 * kmem_cache_shrink - Shrink a cache.
2501 * @cachep: The cache to shrink.
2503 * Releases as many slabs as possible for a cache.
2504 * To help debugging, a zero exit status indicates all slabs were released.
2506 int kmem_cache_shrink(struct kmem_cache *cachep)
2509 BUG_ON(!cachep || in_interrupt());
2512 mutex_lock(&slab_mutex);
2513 ret = __cache_shrink(cachep);
2514 mutex_unlock(&slab_mutex);
2518 EXPORT_SYMBOL(kmem_cache_shrink);
2520 int __kmem_cache_shutdown(struct kmem_cache *cachep)
2523 struct kmem_cache_node *n;
2524 int rc = __cache_shrink(cachep);
2529 for_each_online_cpu(i)
2530 kfree(cachep->array[i]);
2532 /* NUMA: free the node structures */
2533 for_each_online_node(i) {
2534 n = cachep->node[i];
2537 free_alien_cache(n->alien);
2545 * Get the memory for a slab management obj.
2546 * For a slab cache when the slab descriptor is off-slab, slab descriptors
2547 * always come from malloc_sizes caches. The slab descriptor cannot
2548 * come from the same cache which is getting created because,
2549 * when we are searching for an appropriate cache for these
2550 * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2551 * If we are creating a malloc_sizes cache here it would not be visible to
2552 * kmem_find_general_cachep till the initialization is complete.
2553 * Hence we cannot have slabp_cache same as the original cache.
2555 static struct slab *alloc_slabmgmt(struct kmem_cache *cachep,
2556 struct page *page, int colour_off,
2557 gfp_t local_flags, int nodeid)
2560 void *addr = page_address(page);
2562 if (OFF_SLAB(cachep)) {
2563 /* Slab management obj is off-slab. */
2564 slabp = kmem_cache_alloc_node(cachep->slabp_cache,
2565 local_flags, nodeid);
2567 * If the first object in the slab is leaked (it's allocated
2568 * but no one has a reference to it), we want to make sure
2569 * kmemleak does not treat the ->s_mem pointer as a reference
2570 * to the object. Otherwise we will not report the leak.
2572 kmemleak_scan_area(&slabp->list, sizeof(struct list_head),
2577 slabp = addr + colour_off;
2578 colour_off += cachep->slab_size;
2581 slabp->s_mem = addr + colour_off;
2586 static inline unsigned int *slab_bufctl(struct slab *slabp)
2588 return (unsigned int *) (slabp + 1);
2591 static void cache_init_objs(struct kmem_cache *cachep,
2596 for (i = 0; i < cachep->num; i++) {
2597 void *objp = index_to_obj(cachep, slabp, i);
2599 /* need to poison the objs? */
2600 if (cachep->flags & SLAB_POISON)
2601 poison_obj(cachep, objp, POISON_FREE);
2602 if (cachep->flags & SLAB_STORE_USER)
2603 *dbg_userword(cachep, objp) = NULL;
2605 if (cachep->flags & SLAB_RED_ZONE) {
2606 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2607 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2610 * Constructors are not allowed to allocate memory from the same
2611 * cache which they are a constructor for. Otherwise, deadlock.
2612 * They must also be threaded.
2614 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2615 cachep->ctor(objp + obj_offset(cachep));
2617 if (cachep->flags & SLAB_RED_ZONE) {
2618 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2619 slab_error(cachep, "constructor overwrote the"
2620 " end of an object");
2621 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2622 slab_error(cachep, "constructor overwrote the"
2623 " start of an object");
2625 if ((cachep->size % PAGE_SIZE) == 0 &&
2626 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2627 kernel_map_pages(virt_to_page(objp),
2628 cachep->size / PAGE_SIZE, 0);
2633 slab_bufctl(slabp)[i] = i;
2637 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2639 if (CONFIG_ZONE_DMA_FLAG) {
2640 if (flags & GFP_DMA)
2641 BUG_ON(!(cachep->allocflags & GFP_DMA));
2643 BUG_ON(cachep->allocflags & GFP_DMA);
2647 static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
2653 objp = index_to_obj(cachep, slabp, slab_bufctl(slabp)[slabp->free]);
2655 WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);
2662 static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
2663 void *objp, int nodeid)
2665 unsigned int objnr = obj_to_index(cachep, slabp, objp);
2669 /* Verify that the slab belongs to the intended node */
2670 WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);
2672 /* Verify double free bug */
2673 for (i = slabp->free; i < cachep->num; i++) {
2674 if (slab_bufctl(slabp)[i] == objnr) {
2675 printk(KERN_ERR "slab: double free detected in cache "
2676 "'%s', objp %p\n", cachep->name, objp);
2682 slab_bufctl(slabp)[slabp->free] = objnr;
2687 * Map pages beginning at addr to the given cache and slab. This is required
2688 * for the slab allocator to be able to lookup the cache and slab of a
2689 * virtual address for kfree, ksize, and slab debugging.
2691 static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
2694 page->slab_cache = cache;
2695 page->slab_page = slab;
2699 * Grow (by 1) the number of slabs within a cache. This is called by
2700 * kmem_cache_alloc() when there are no active objs left in a cache.
2702 static int cache_grow(struct kmem_cache *cachep,
2703 gfp_t flags, int nodeid, struct page *page)
2708 struct kmem_cache_node *n;
2711 * Be lazy and only check for valid flags here, keeping it out of the
2712 * critical path in kmem_cache_alloc().
2714 BUG_ON(flags & GFP_SLAB_BUG_MASK);
2715 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2717 /* Take the node list lock to change the colour_next on this node */
2719 n = cachep->node[nodeid];
2720 spin_lock(&n->list_lock);
2722 /* Get colour for the slab, and cal the next value. */
2723 offset = n->colour_next;
2725 if (n->colour_next >= cachep->colour)
2727 spin_unlock(&n->list_lock);
2729 offset *= cachep->colour_off;
2731 if (local_flags & __GFP_WAIT)
2735 * The test for missing atomic flag is performed here, rather than
2736 * the more obvious place, simply to reduce the critical path length
2737 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2738 * will eventually be caught here (where it matters).
2740 kmem_flagcheck(cachep, flags);
2743 * Get mem for the objs. Attempt to allocate a physical page from
2747 page = kmem_getpages(cachep, local_flags, nodeid);
2751 /* Get slab management. */
2752 slabp = alloc_slabmgmt(cachep, page, offset,
2753 local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
2757 slab_map_pages(cachep, slabp, page);
2759 cache_init_objs(cachep, slabp);
2761 if (local_flags & __GFP_WAIT)
2762 local_irq_disable();
2764 spin_lock(&n->list_lock);
2766 /* Make slab active. */
2767 list_add_tail(&slabp->list, &(n->slabs_free));
2768 STATS_INC_GROWN(cachep);
2769 n->free_objects += cachep->num;
2770 spin_unlock(&n->list_lock);
2773 kmem_freepages(cachep, page);
2775 if (local_flags & __GFP_WAIT)
2776 local_irq_disable();
2783 * Perform extra freeing checks:
2784 * - detect bad pointers.
2785 * - POISON/RED_ZONE checking
2787 static void kfree_debugcheck(const void *objp)
2789 if (!virt_addr_valid(objp)) {
2790 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2791 (unsigned long)objp);
2796 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2798 unsigned long long redzone1, redzone2;
2800 redzone1 = *dbg_redzone1(cache, obj);
2801 redzone2 = *dbg_redzone2(cache, obj);
2806 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2809 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2810 slab_error(cache, "double free detected");
2812 slab_error(cache, "memory outside object was overwritten");
2814 printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
2815 obj, redzone1, redzone2);
2818 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2819 unsigned long caller)
2824 BUG_ON(virt_to_cache(objp) != cachep);
2826 objp -= obj_offset(cachep);
2827 kfree_debugcheck(objp);
2828 slabp = virt_to_slab(objp);
2830 if (cachep->flags & SLAB_RED_ZONE) {
2831 verify_redzone_free(cachep, objp);
2832 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2833 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2835 if (cachep->flags & SLAB_STORE_USER)
2836 *dbg_userword(cachep, objp) = (void *)caller;
2838 objnr = obj_to_index(cachep, slabp, objp);
2840 BUG_ON(objnr >= cachep->num);
2841 BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
2843 if (cachep->flags & SLAB_POISON) {
2844 #ifdef CONFIG_DEBUG_PAGEALLOC
2845 if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2846 store_stackinfo(cachep, objp, caller);
2847 kernel_map_pages(virt_to_page(objp),
2848 cachep->size / PAGE_SIZE, 0);
2850 poison_obj(cachep, objp, POISON_FREE);
2853 poison_obj(cachep, objp, POISON_FREE);
2860 #define kfree_debugcheck(x) do { } while(0)
2861 #define cache_free_debugcheck(x,objp,z) (objp)
2864 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags,
2868 struct kmem_cache_node *n;
2869 struct array_cache *ac;
2873 node = numa_mem_id();
2874 if (unlikely(force_refill))
2877 ac = cpu_cache_get(cachep);
2878 batchcount = ac->batchcount;
2879 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2881 * If there was little recent activity on this cache, then
2882 * perform only a partial refill. Otherwise we could generate
2885 batchcount = BATCHREFILL_LIMIT;
2887 n = cachep->node[node];
2889 BUG_ON(ac->avail > 0 || !n);
2890 spin_lock(&n->list_lock);
2892 /* See if we can refill from the shared array */
2893 if (n->shared && transfer_objects(ac, n->shared, batchcount)) {
2894 n->shared->touched = 1;
2898 while (batchcount > 0) {
2899 struct list_head *entry;
2901 /* Get slab alloc is to come from. */
2902 entry = n->slabs_partial.next;
2903 if (entry == &n->slabs_partial) {
2904 n->free_touched = 1;
2905 entry = n->slabs_free.next;
2906 if (entry == &n->slabs_free)
2910 slabp = list_entry(entry, struct slab, list);
2911 check_spinlock_acquired(cachep);
2914 * The slab was either on partial or free list so
2915 * there must be at least one object available for
2918 BUG_ON(slabp->inuse >= cachep->num);
2920 while (slabp->inuse < cachep->num && batchcount--) {
2921 STATS_INC_ALLOCED(cachep);
2922 STATS_INC_ACTIVE(cachep);
2923 STATS_SET_HIGH(cachep);
2925 ac_put_obj(cachep, ac, slab_get_obj(cachep, slabp,
2929 /* move slabp to correct slabp list: */
2930 list_del(&slabp->list);
2931 if (slabp->free == cachep->num)
2932 list_add(&slabp->list, &n->slabs_full);
2934 list_add(&slabp->list, &n->slabs_partial);
2938 n->free_objects -= ac->avail;
2940 spin_unlock(&n->list_lock);
2942 if (unlikely(!ac->avail)) {
2945 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
2947 /* cache_grow can reenable interrupts, then ac could change. */
2948 ac = cpu_cache_get(cachep);
2949 node = numa_mem_id();
2951 /* no objects in sight? abort */
2952 if (!x && (ac->avail == 0 || force_refill))
2955 if (!ac->avail) /* objects refilled by interrupt? */
2960 return ac_get_obj(cachep, ac, flags, force_refill);
2963 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
2966 might_sleep_if(flags & __GFP_WAIT);
2968 kmem_flagcheck(cachep, flags);
2973 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
2974 gfp_t flags, void *objp, unsigned long caller)
2978 if (cachep->flags & SLAB_POISON) {
2979 #ifdef CONFIG_DEBUG_PAGEALLOC
2980 if ((cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
2981 kernel_map_pages(virt_to_page(objp),
2982 cachep->size / PAGE_SIZE, 1);
2984 check_poison_obj(cachep, objp);
2986 check_poison_obj(cachep, objp);
2988 poison_obj(cachep, objp, POISON_INUSE);
2990 if (cachep->flags & SLAB_STORE_USER)
2991 *dbg_userword(cachep, objp) = (void *)caller;
2993 if (cachep->flags & SLAB_RED_ZONE) {
2994 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
2995 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
2996 slab_error(cachep, "double free, or memory outside"
2997 " object was overwritten");
2999 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3000 objp, *dbg_redzone1(cachep, objp),
3001 *dbg_redzone2(cachep, objp));
3003 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
3004 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
3006 objp += obj_offset(cachep);
3007 if (cachep->ctor && cachep->flags & SLAB_POISON)
3009 if (ARCH_SLAB_MINALIGN &&
3010 ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
3011 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3012 objp, (int)ARCH_SLAB_MINALIGN);
3017 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3020 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
3022 if (cachep == kmem_cache)
3025 return should_failslab(cachep->object_size, flags, cachep->flags);
3028 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3031 struct array_cache *ac;
3032 bool force_refill = false;
3036 ac = cpu_cache_get(cachep);
3037 if (likely(ac->avail)) {
3039 objp = ac_get_obj(cachep, ac, flags, false);
3042 * Allow for the possibility all avail objects are not allowed
3043 * by the current flags
3046 STATS_INC_ALLOCHIT(cachep);
3049 force_refill = true;
3052 STATS_INC_ALLOCMISS(cachep);
3053 objp = cache_alloc_refill(cachep, flags, force_refill);
3055 * the 'ac' may be updated by cache_alloc_refill(),
3056 * and kmemleak_erase() requires its correct value.
3058 ac = cpu_cache_get(cachep);
3062 * To avoid a false negative, if an object that is in one of the
3063 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3064 * treat the array pointers as a reference to the object.
3067 kmemleak_erase(&ac->entry[ac->avail]);
3073 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3075 * If we are in_interrupt, then process context, including cpusets and
3076 * mempolicy, may not apply and should not be used for allocation policy.
3078 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3080 int nid_alloc, nid_here;
3082 if (in_interrupt() || (flags & __GFP_THISNODE))
3084 nid_alloc = nid_here = numa_mem_id();
3085 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3086 nid_alloc = cpuset_slab_spread_node();
3087 else if (current->mempolicy)
3088 nid_alloc = slab_node();
3089 if (nid_alloc != nid_here)
3090 return ____cache_alloc_node(cachep, flags, nid_alloc);
3095 * Fallback function if there was no memory available and no objects on a
3096 * certain node and fall back is permitted. First we scan all the
3097 * available node for available objects. If that fails then we
3098 * perform an allocation without specifying a node. This allows the page
3099 * allocator to do its reclaim / fallback magic. We then insert the
3100 * slab into the proper nodelist and then allocate from it.
3102 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3104 struct zonelist *zonelist;
3108 enum zone_type high_zoneidx = gfp_zone(flags);
3111 unsigned int cpuset_mems_cookie;
3113 if (flags & __GFP_THISNODE)
3116 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
3119 cpuset_mems_cookie = get_mems_allowed();
3120 zonelist = node_zonelist(slab_node(), flags);
3124 * Look through allowed nodes for objects available
3125 * from existing per node queues.
3127 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3128 nid = zone_to_nid(zone);
3130 if (cpuset_zone_allowed_hardwall(zone, flags) &&
3132 cache->node[nid]->free_objects) {
3133 obj = ____cache_alloc_node(cache,
3134 flags | GFP_THISNODE, nid);
3142 * This allocation will be performed within the constraints
3143 * of the current cpuset / memory policy requirements.
3144 * We may trigger various forms of reclaim on the allowed
3145 * set and go into memory reserves if necessary.
3149 if (local_flags & __GFP_WAIT)
3151 kmem_flagcheck(cache, flags);
3152 page = kmem_getpages(cache, local_flags, numa_mem_id());
3153 if (local_flags & __GFP_WAIT)
3154 local_irq_disable();
3157 * Insert into the appropriate per node queues
3159 nid = page_to_nid(page);
3160 if (cache_grow(cache, flags, nid, page)) {
3161 obj = ____cache_alloc_node(cache,
3162 flags | GFP_THISNODE, nid);
3165 * Another processor may allocate the
3166 * objects in the slab since we are
3167 * not holding any locks.
3171 /* cache_grow already freed obj */
3177 if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !obj))
3183 * A interface to enable slab creation on nodeid
3185 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3188 struct list_head *entry;
3190 struct kmem_cache_node *n;
3194 VM_BUG_ON(nodeid > num_online_nodes());
3195 n = cachep->node[nodeid];
3200 spin_lock(&n->list_lock);
3201 entry = n->slabs_partial.next;
3202 if (entry == &n->slabs_partial) {
3203 n->free_touched = 1;
3204 entry = n->slabs_free.next;
3205 if (entry == &n->slabs_free)
3209 slabp = list_entry(entry, struct slab, list);
3210 check_spinlock_acquired_node(cachep, nodeid);
3212 STATS_INC_NODEALLOCS(cachep);
3213 STATS_INC_ACTIVE(cachep);
3214 STATS_SET_HIGH(cachep);
3216 BUG_ON(slabp->inuse == cachep->num);
3218 obj = slab_get_obj(cachep, slabp, nodeid);
3220 /* move slabp to correct slabp list: */
3221 list_del(&slabp->list);
3223 if (slabp->free == cachep->num)
3224 list_add(&slabp->list, &n->slabs_full);
3226 list_add(&slabp->list, &n->slabs_partial);
3228 spin_unlock(&n->list_lock);
3232 spin_unlock(&n->list_lock);
3233 x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
3237 return fallback_alloc(cachep, flags);
3243 static __always_inline void *
3244 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3245 unsigned long caller)
3247 unsigned long save_flags;
3249 int slab_node = numa_mem_id();
3251 flags &= gfp_allowed_mask;
3253 lockdep_trace_alloc(flags);
3255 if (slab_should_failslab(cachep, flags))
3258 cachep = memcg_kmem_get_cache(cachep, flags);
3260 cache_alloc_debugcheck_before(cachep, flags);
3261 local_irq_save(save_flags);
3263 if (nodeid == NUMA_NO_NODE)
3266 if (unlikely(!cachep->node[nodeid])) {
3267 /* Node not bootstrapped yet */
3268 ptr = fallback_alloc(cachep, flags);
3272 if (nodeid == slab_node) {
3274 * Use the locally cached objects if possible.
3275 * However ____cache_alloc does not allow fallback
3276 * to other nodes. It may fail while we still have
3277 * objects on other nodes available.
3279 ptr = ____cache_alloc(cachep, flags);
3283 /* ___cache_alloc_node can fall back to other nodes */
3284 ptr = ____cache_alloc_node(cachep, flags, nodeid);
3286 local_irq_restore(save_flags);
3287 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3288 kmemleak_alloc_recursive(ptr, cachep->object_size, 1, cachep->flags,
3292 kmemcheck_slab_alloc(cachep, flags, ptr, cachep->object_size);
3294 if (unlikely((flags & __GFP_ZERO) && ptr))
3295 memset(ptr, 0, cachep->object_size);
3300 static __always_inline void *
3301 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3305 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
3306 objp = alternate_node_alloc(cache, flags);
3310 objp = ____cache_alloc(cache, flags);
3313 * We may just have run out of memory on the local node.
3314 * ____cache_alloc_node() knows how to locate memory on other nodes
3317 objp = ____cache_alloc_node(cache, flags, numa_mem_id());
3324 static __always_inline void *
3325 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3327 return ____cache_alloc(cachep, flags);
3330 #endif /* CONFIG_NUMA */
3332 static __always_inline void *
3333 slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
3335 unsigned long save_flags;
3338 flags &= gfp_allowed_mask;
3340 lockdep_trace_alloc(flags);
3342 if (slab_should_failslab(cachep, flags))
3345 cachep = memcg_kmem_get_cache(cachep, flags);
3347 cache_alloc_debugcheck_before(cachep, flags);
3348 local_irq_save(save_flags);
3349 objp = __do_cache_alloc(cachep, flags);
3350 local_irq_restore(save_flags);
3351 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3352 kmemleak_alloc_recursive(objp, cachep->object_size, 1, cachep->flags,
3357 kmemcheck_slab_alloc(cachep, flags, objp, cachep->object_size);
3359 if (unlikely((flags & __GFP_ZERO) && objp))
3360 memset(objp, 0, cachep->object_size);
3366 * Caller needs to acquire correct kmem_list's list_lock
3368 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
3372 struct kmem_cache_node *n;
3374 for (i = 0; i < nr_objects; i++) {
3378 clear_obj_pfmemalloc(&objpp[i]);
3381 slabp = virt_to_slab(objp);
3382 n = cachep->node[node];
3383 list_del(&slabp->list);
3384 check_spinlock_acquired_node(cachep, node);
3385 slab_put_obj(cachep, slabp, objp, node);
3386 STATS_DEC_ACTIVE(cachep);
3389 /* fixup slab chains */
3390 if (slabp->inuse == 0) {
3391 if (n->free_objects > n->free_limit) {
3392 n->free_objects -= cachep->num;
3393 /* No need to drop any previously held
3394 * lock here, even if we have a off-slab slab
3395 * descriptor it is guaranteed to come from
3396 * a different cache, refer to comments before
3399 slab_destroy(cachep, slabp);
3401 list_add(&slabp->list, &n->slabs_free);
3404 /* Unconditionally move a slab to the end of the
3405 * partial list on free - maximum time for the
3406 * other objects to be freed, too.
3408 list_add_tail(&slabp->list, &n->slabs_partial);
3413 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3416 struct kmem_cache_node *n;
3417 int node = numa_mem_id();
3419 batchcount = ac->batchcount;
3421 BUG_ON(!batchcount || batchcount > ac->avail);
3424 n = cachep->node[node];
3425 spin_lock(&n->list_lock);
3427 struct array_cache *shared_array = n->shared;
3428 int max = shared_array->limit - shared_array->avail;
3430 if (batchcount > max)
3432 memcpy(&(shared_array->entry[shared_array->avail]),
3433 ac->entry, sizeof(void *) * batchcount);
3434 shared_array->avail += batchcount;
3439 free_block(cachep, ac->entry, batchcount, node);
3444 struct list_head *p;
3446 p = n->slabs_free.next;
3447 while (p != &(n->slabs_free)) {
3450 slabp = list_entry(p, struct slab, list);
3451 BUG_ON(slabp->inuse);
3456 STATS_SET_FREEABLE(cachep, i);
3459 spin_unlock(&n->list_lock);
3460 ac->avail -= batchcount;
3461 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3465 * Release an obj back to its cache. If the obj has a constructed state, it must
3466 * be in this state _before_ it is released. Called with disabled ints.
3468 static inline void __cache_free(struct kmem_cache *cachep, void *objp,
3469 unsigned long caller)
3471 struct array_cache *ac = cpu_cache_get(cachep);
3474 kmemleak_free_recursive(objp, cachep->flags);
3475 objp = cache_free_debugcheck(cachep, objp, caller);
3477 kmemcheck_slab_free(cachep, objp, cachep->object_size);
3480 * Skip calling cache_free_alien() when the platform is not numa.
3481 * This will avoid cache misses that happen while accessing slabp (which
3482 * is per page memory reference) to get nodeid. Instead use a global
3483 * variable to skip the call, which is mostly likely to be present in
3486 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3489 if (likely(ac->avail < ac->limit)) {
3490 STATS_INC_FREEHIT(cachep);
3492 STATS_INC_FREEMISS(cachep);
3493 cache_flusharray(cachep, ac);
3496 ac_put_obj(cachep, ac, objp);
3500 * kmem_cache_alloc - Allocate an object
3501 * @cachep: The cache to allocate from.
3502 * @flags: See kmalloc().
3504 * Allocate an object from this cache. The flags are only relevant
3505 * if the cache has no available objects.
3507 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3509 void *ret = slab_alloc(cachep, flags, _RET_IP_);
3511 trace_kmem_cache_alloc(_RET_IP_, ret,
3512 cachep->object_size, cachep->size, flags);
3516 EXPORT_SYMBOL(kmem_cache_alloc);
3518 #ifdef CONFIG_TRACING
3520 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
3524 ret = slab_alloc(cachep, flags, _RET_IP_);
3526 trace_kmalloc(_RET_IP_, ret,
3527 size, cachep->size, flags);
3530 EXPORT_SYMBOL(kmem_cache_alloc_trace);
3535 * kmem_cache_alloc_node - Allocate an object on the specified node
3536 * @cachep: The cache to allocate from.
3537 * @flags: See kmalloc().
3538 * @nodeid: node number of the target node.
3540 * Identical to kmem_cache_alloc but it will allocate memory on the given
3541 * node, which can improve the performance for cpu bound structures.
3543 * Fallback to other node is possible if __GFP_THISNODE is not set.
3545 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3547 void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3549 trace_kmem_cache_alloc_node(_RET_IP_, ret,
3550 cachep->object_size, cachep->size,
3555 EXPORT_SYMBOL(kmem_cache_alloc_node);
3557 #ifdef CONFIG_TRACING
3558 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
3565 ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3567 trace_kmalloc_node(_RET_IP_, ret,
3572 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3575 static __always_inline void *
3576 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
3578 struct kmem_cache *cachep;
3580 cachep = kmalloc_slab(size, flags);
3581 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3583 return kmem_cache_alloc_node_trace(cachep, flags, node, size);
3586 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3587 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3589 return __do_kmalloc_node(size, flags, node, _RET_IP_);
3591 EXPORT_SYMBOL(__kmalloc_node);
3593 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3594 int node, unsigned long caller)
3596 return __do_kmalloc_node(size, flags, node, caller);
3598 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3600 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3602 return __do_kmalloc_node(size, flags, node, 0);
3604 EXPORT_SYMBOL(__kmalloc_node);
3605 #endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */
3606 #endif /* CONFIG_NUMA */
3609 * __do_kmalloc - allocate memory
3610 * @size: how many bytes of memory are required.
3611 * @flags: the type of memory to allocate (see kmalloc).
3612 * @caller: function caller for debug tracking of the caller
3614 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3615 unsigned long caller)
3617 struct kmem_cache *cachep;
3620 /* If you want to save a few bytes .text space: replace
3622 * Then kmalloc uses the uninlined functions instead of the inline
3625 cachep = kmalloc_slab(size, flags);
3626 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3628 ret = slab_alloc(cachep, flags, caller);
3630 trace_kmalloc(caller, ret,
3631 size, cachep->size, flags);
3637 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3638 void *__kmalloc(size_t size, gfp_t flags)
3640 return __do_kmalloc(size, flags, _RET_IP_);
3642 EXPORT_SYMBOL(__kmalloc);
3644 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3646 return __do_kmalloc(size, flags, caller);
3648 EXPORT_SYMBOL(__kmalloc_track_caller);
3651 void *__kmalloc(size_t size, gfp_t flags)
3653 return __do_kmalloc(size, flags, 0);
3655 EXPORT_SYMBOL(__kmalloc);
3659 * kmem_cache_free - Deallocate an object
3660 * @cachep: The cache the allocation was from.
3661 * @objp: The previously allocated object.
3663 * Free an object which was previously allocated from this
3666 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3668 unsigned long flags;
3669 cachep = cache_from_obj(cachep, objp);
3673 local_irq_save(flags);
3674 debug_check_no_locks_freed(objp, cachep->object_size);
3675 if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3676 debug_check_no_obj_freed(objp, cachep->object_size);
3677 __cache_free(cachep, objp, _RET_IP_);
3678 local_irq_restore(flags);
3680 trace_kmem_cache_free(_RET_IP_, objp);
3682 EXPORT_SYMBOL(kmem_cache_free);
3685 * kfree - free previously allocated memory
3686 * @objp: pointer returned by kmalloc.
3688 * If @objp is NULL, no operation is performed.
3690 * Don't free memory not originally allocated by kmalloc()
3691 * or you will run into trouble.
3693 void kfree(const void *objp)
3695 struct kmem_cache *c;
3696 unsigned long flags;
3698 trace_kfree(_RET_IP_, objp);
3700 if (unlikely(ZERO_OR_NULL_PTR(objp)))
3702 local_irq_save(flags);
3703 kfree_debugcheck(objp);
3704 c = virt_to_cache(objp);
3705 debug_check_no_locks_freed(objp, c->object_size);
3707 debug_check_no_obj_freed(objp, c->object_size);
3708 __cache_free(c, (void *)objp, _RET_IP_);
3709 local_irq_restore(flags);
3711 EXPORT_SYMBOL(kfree);
3714 * This initializes kmem_cache_node or resizes various caches for all nodes.
3716 static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
3719 struct kmem_cache_node *n;
3720 struct array_cache *new_shared;
3721 struct array_cache **new_alien = NULL;
3723 for_each_online_node(node) {
3725 if (use_alien_caches) {
3726 new_alien = alloc_alien_cache(node, cachep->limit, gfp);
3732 if (cachep->shared) {
3733 new_shared = alloc_arraycache(node,
3734 cachep->shared*cachep->batchcount,
3737 free_alien_cache(new_alien);
3742 n = cachep->node[node];
3744 struct array_cache *shared = n->shared;
3746 spin_lock_irq(&n->list_lock);
3749 free_block(cachep, shared->entry,
3750 shared->avail, node);
3752 n->shared = new_shared;
3754 n->alien = new_alien;
3757 n->free_limit = (1 + nr_cpus_node(node)) *
3758 cachep->batchcount + cachep->num;
3759 spin_unlock_irq(&n->list_lock);
3761 free_alien_cache(new_alien);
3764 n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
3766 free_alien_cache(new_alien);
3771 kmem_cache_node_init(n);
3772 n->next_reap = jiffies + REAPTIMEOUT_LIST3 +
3773 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
3774 n->shared = new_shared;
3775 n->alien = new_alien;
3776 n->free_limit = (1 + nr_cpus_node(node)) *
3777 cachep->batchcount + cachep->num;
3778 cachep->node[node] = n;
3783 if (!cachep->list.next) {
3784 /* Cache is not active yet. Roll back what we did */
3787 if (cachep->node[node]) {
3788 n = cachep->node[node];
3791 free_alien_cache(n->alien);
3793 cachep->node[node] = NULL;
3801 struct ccupdate_struct {
3802 struct kmem_cache *cachep;
3803 struct array_cache *new[0];
3806 static void do_ccupdate_local(void *info)
3808 struct ccupdate_struct *new = info;
3809 struct array_cache *old;
3812 old = cpu_cache_get(new->cachep);
3814 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
3815 new->new[smp_processor_id()] = old;
3818 /* Always called with the slab_mutex held */
3819 static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
3820 int batchcount, int shared, gfp_t gfp)
3822 struct ccupdate_struct *new;
3825 new = kzalloc(sizeof(*new) + nr_cpu_ids * sizeof(struct array_cache *),
3830 for_each_online_cpu(i) {
3831 new->new[i] = alloc_arraycache(cpu_to_mem(i), limit,
3834 for (i--; i >= 0; i--)
3840 new->cachep = cachep;
3842 on_each_cpu(do_ccupdate_local, (void *)new, 1);
3845 cachep->batchcount = batchcount;
3846 cachep->limit = limit;
3847 cachep->shared = shared;
3849 for_each_online_cpu(i) {
3850 struct array_cache *ccold = new->new[i];
3853 spin_lock_irq(&cachep->node[cpu_to_mem(i)]->list_lock);
3854 free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i));
3855 spin_unlock_irq(&cachep->node[cpu_to_mem(i)]->list_lock);
3859 return alloc_kmemlist(cachep, gfp);
3862 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3863 int batchcount, int shared, gfp_t gfp)
3866 struct kmem_cache *c = NULL;
3869 ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3871 if (slab_state < FULL)
3874 if ((ret < 0) || !is_root_cache(cachep))
3877 VM_BUG_ON(!mutex_is_locked(&slab_mutex));
3878 for_each_memcg_cache_index(i) {
3879 c = cache_from_memcg(cachep, i);
3881 /* return value determined by the parent cache only */
3882 __do_tune_cpucache(c, limit, batchcount, shared, gfp);
3888 /* Called with slab_mutex held always */
3889 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3896 if (!is_root_cache(cachep)) {
3897 struct kmem_cache *root = memcg_root_cache(cachep);
3898 limit = root->limit;
3899 shared = root->shared;
3900 batchcount = root->batchcount;
3903 if (limit && shared && batchcount)
3906 * The head array serves three purposes:
3907 * - create a LIFO ordering, i.e. return objects that are cache-warm
3908 * - reduce the number of spinlock operations.
3909 * - reduce the number of linked list operations on the slab and
3910 * bufctl chains: array operations are cheaper.
3911 * The numbers are guessed, we should auto-tune as described by
3914 if (cachep->size > 131072)
3916 else if (cachep->size > PAGE_SIZE)
3918 else if (cachep->size > 1024)
3920 else if (cachep->size > 256)
3926 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3927 * allocation behaviour: Most allocs on one cpu, most free operations
3928 * on another cpu. For these cases, an efficient object passing between
3929 * cpus is necessary. This is provided by a shared array. The array
3930 * replaces Bonwick's magazine layer.
3931 * On uniprocessor, it's functionally equivalent (but less efficient)
3932 * to a larger limit. Thus disabled by default.
3935 if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
3940 * With debugging enabled, large batchcount lead to excessively long
3941 * periods with disabled local interrupts. Limit the batchcount
3946 batchcount = (limit + 1) / 2;
3948 err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3950 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
3951 cachep->name, -err);
3956 * Drain an array if it contains any elements taking the node lock only if
3957 * necessary. Note that the node listlock also protects the array_cache
3958 * if drain_array() is used on the shared array.
3960 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
3961 struct array_cache *ac, int force, int node)
3965 if (!ac || !ac->avail)
3967 if (ac->touched && !force) {
3970 spin_lock_irq(&n->list_lock);
3972 tofree = force ? ac->avail : (ac->limit + 4) / 5;
3973 if (tofree > ac->avail)
3974 tofree = (ac->avail + 1) / 2;
3975 free_block(cachep, ac->entry, tofree, node);
3976 ac->avail -= tofree;
3977 memmove(ac->entry, &(ac->entry[tofree]),
3978 sizeof(void *) * ac->avail);
3980 spin_unlock_irq(&n->list_lock);
3985 * cache_reap - Reclaim memory from caches.
3986 * @w: work descriptor
3988 * Called from workqueue/eventd every few seconds.
3990 * - clear the per-cpu caches for this CPU.
3991 * - return freeable pages to the main free memory pool.
3993 * If we cannot acquire the cache chain mutex then just give up - we'll try
3994 * again on the next iteration.
3996 static void cache_reap(struct work_struct *w)
3998 struct kmem_cache *searchp;
3999 struct kmem_cache_node *n;
4000 int node = numa_mem_id();
4001 struct delayed_work *work = to_delayed_work(w);
4003 if (!mutex_trylock(&slab_mutex))
4004 /* Give up. Setup the next iteration. */
4007 list_for_each_entry(searchp, &slab_caches, list) {
4011 * We only take the node lock if absolutely necessary and we
4012 * have established with reasonable certainty that
4013 * we can do some work if the lock was obtained.
4015 n = searchp->node[node];
4017 reap_alien(searchp, n);
4019 drain_array(searchp, n, cpu_cache_get(searchp), 0, node);
4022 * These are racy checks but it does not matter
4023 * if we skip one check or scan twice.
4025 if (time_after(n->next_reap, jiffies))
4028 n->next_reap = jiffies + REAPTIMEOUT_LIST3;
4030 drain_array(searchp, n, n->shared, 0, node);
4032 if (n->free_touched)
4033 n->free_touched = 0;
4037 freed = drain_freelist(searchp, n, (n->free_limit +
4038 5 * searchp->num - 1) / (5 * searchp->num));
4039 STATS_ADD_REAPED(searchp, freed);
4045 mutex_unlock(&slab_mutex);
4048 /* Set up the next iteration */
4049 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
4052 #ifdef CONFIG_SLABINFO
4053 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
4056 unsigned long active_objs;
4057 unsigned long num_objs;
4058 unsigned long active_slabs = 0;
4059 unsigned long num_slabs, free_objects = 0, shared_avail = 0;
4063 struct kmem_cache_node *n;
4067 for_each_online_node(node) {
4068 n = cachep->node[node];
4073 spin_lock_irq(&n->list_lock);
4075 list_for_each_entry(slabp, &n->slabs_full, list) {
4076 if (slabp->inuse != cachep->num && !error)
4077 error = "slabs_full accounting error";
4078 active_objs += cachep->num;
4081 list_for_each_entry(slabp, &n->slabs_partial, list) {
4082 if (slabp->inuse == cachep->num && !error)
4083 error = "slabs_partial inuse accounting error";
4084 if (!slabp->inuse && !error)
4085 error = "slabs_partial/inuse accounting error";
4086 active_objs += slabp->inuse;
4089 list_for_each_entry(slabp, &n->slabs_free, list) {
4090 if (slabp->inuse && !error)
4091 error = "slabs_free/inuse accounting error";
4094 free_objects += n->free_objects;
4096 shared_avail += n->shared->avail;
4098 spin_unlock_irq(&n->list_lock);
4100 num_slabs += active_slabs;
4101 num_objs = num_slabs * cachep->num;
4102 if (num_objs - active_objs != free_objects && !error)
4103 error = "free_objects accounting error";
4105 name = cachep->name;
4107 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
4109 sinfo->active_objs = active_objs;
4110 sinfo->num_objs = num_objs;
4111 sinfo->active_slabs = active_slabs;
4112 sinfo->num_slabs = num_slabs;
4113 sinfo->shared_avail = shared_avail;
4114 sinfo->limit = cachep->limit;
4115 sinfo->batchcount = cachep->batchcount;
4116 sinfo->shared = cachep->shared;
4117 sinfo->objects_per_slab = cachep->num;
4118 sinfo->cache_order = cachep->gfporder;
4121 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
4125 unsigned long high = cachep->high_mark;
4126 unsigned long allocs = cachep->num_allocations;
4127 unsigned long grown = cachep->grown;
4128 unsigned long reaped = cachep->reaped;
4129 unsigned long errors = cachep->errors;
4130 unsigned long max_freeable = cachep->max_freeable;
4131 unsigned long node_allocs = cachep->node_allocs;
4132 unsigned long node_frees = cachep->node_frees;
4133 unsigned long overflows = cachep->node_overflow;
4135 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu "
4136 "%4lu %4lu %4lu %4lu %4lu",
4137 allocs, high, grown,
4138 reaped, errors, max_freeable, node_allocs,
4139 node_frees, overflows);
4143 unsigned long allochit = atomic_read(&cachep->allochit);
4144 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4145 unsigned long freehit = atomic_read(&cachep->freehit);
4146 unsigned long freemiss = atomic_read(&cachep->freemiss);
4148 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4149 allochit, allocmiss, freehit, freemiss);
4154 #define MAX_SLABINFO_WRITE 128
4156 * slabinfo_write - Tuning for the slab allocator
4158 * @buffer: user buffer
4159 * @count: data length
4162 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
4163 size_t count, loff_t *ppos)
4165 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4166 int limit, batchcount, shared, res;
4167 struct kmem_cache *cachep;
4169 if (count > MAX_SLABINFO_WRITE)
4171 if (copy_from_user(&kbuf, buffer, count))
4173 kbuf[MAX_SLABINFO_WRITE] = '\0';
4175 tmp = strchr(kbuf, ' ');
4180 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4183 /* Find the cache in the chain of caches. */
4184 mutex_lock(&slab_mutex);
4186 list_for_each_entry(cachep, &slab_caches, list) {
4187 if (!strcmp(cachep->name, kbuf)) {
4188 if (limit < 1 || batchcount < 1 ||
4189 batchcount > limit || shared < 0) {
4192 res = do_tune_cpucache(cachep, limit,
4199 mutex_unlock(&slab_mutex);
4205 #ifdef CONFIG_DEBUG_SLAB_LEAK
4207 static void *leaks_start(struct seq_file *m, loff_t *pos)
4209 mutex_lock(&slab_mutex);
4210 return seq_list_start(&slab_caches, *pos);
4213 static inline int add_caller(unsigned long *n, unsigned long v)
4223 unsigned long *q = p + 2 * i;
4237 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4243 static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
4250 for (i = 0, p = s->s_mem; i < c->num; i++, p += c->size) {
4253 for (j = s->free; j < c->num; j++) {
4254 /* Skip freed item */
4255 if (slab_bufctl(s)[j] == i) {
4263 if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4268 static void show_symbol(struct seq_file *m, unsigned long address)
4270 #ifdef CONFIG_KALLSYMS
4271 unsigned long offset, size;
4272 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4274 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4275 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4277 seq_printf(m, " [%s]", modname);
4281 seq_printf(m, "%p", (void *)address);
4284 static int leaks_show(struct seq_file *m, void *p)
4286 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
4288 struct kmem_cache_node *n;
4290 unsigned long *x = m->private;
4294 if (!(cachep->flags & SLAB_STORE_USER))
4296 if (!(cachep->flags & SLAB_RED_ZONE))
4299 /* OK, we can do it */
4303 for_each_online_node(node) {
4304 n = cachep->node[node];
4309 spin_lock_irq(&n->list_lock);
4311 list_for_each_entry(slabp, &n->slabs_full, list)
4312 handle_slab(x, cachep, slabp);
4313 list_for_each_entry(slabp, &n->slabs_partial, list)
4314 handle_slab(x, cachep, slabp);
4315 spin_unlock_irq(&n->list_lock);
4317 name = cachep->name;
4319 /* Increase the buffer size */
4320 mutex_unlock(&slab_mutex);
4321 m->private = kzalloc(x[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4323 /* Too bad, we are really out */
4325 mutex_lock(&slab_mutex);
4328 *(unsigned long *)m->private = x[0] * 2;
4330 mutex_lock(&slab_mutex);
4331 /* Now make sure this entry will be retried */
4335 for (i = 0; i < x[1]; i++) {
4336 seq_printf(m, "%s: %lu ", name, x[2*i+3]);
4337 show_symbol(m, x[2*i+2]);
4344 static const struct seq_operations slabstats_op = {
4345 .start = leaks_start,
4351 static int slabstats_open(struct inode *inode, struct file *file)
4353 unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL);
4356 ret = seq_open(file, &slabstats_op);
4358 struct seq_file *m = file->private_data;
4359 *n = PAGE_SIZE / (2 * sizeof(unsigned long));
4368 static const struct file_operations proc_slabstats_operations = {
4369 .open = slabstats_open,
4371 .llseek = seq_lseek,
4372 .release = seq_release_private,
4376 static int __init slab_proc_init(void)
4378 #ifdef CONFIG_DEBUG_SLAB_LEAK
4379 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4383 module_init(slab_proc_init);
4387 * ksize - get the actual amount of memory allocated for a given object
4388 * @objp: Pointer to the object
4390 * kmalloc may internally round up allocations and return more memory
4391 * than requested. ksize() can be used to determine the actual amount of
4392 * memory allocated. The caller may use this additional memory, even though
4393 * a smaller amount of memory was initially specified with the kmalloc call.
4394 * The caller must guarantee that objp points to a valid object previously
4395 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4396 * must not be freed during the duration of the call.
4398 size_t ksize(const void *objp)
4401 if (unlikely(objp == ZERO_SIZE_PTR))
4404 return virt_to_cache(objp)->object_size;
4406 EXPORT_SYMBOL(ksize);