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 'cache_chain_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/kmemtrace.h>
106 #include <linux/rcupdate.h>
107 #include <linux/string.h>
108 #include <linux/uaccess.h>
109 #include <linux/nodemask.h>
110 #include <linux/kmemleak.h>
111 #include <linux/mempolicy.h>
112 #include <linux/mutex.h>
113 #include <linux/fault-inject.h>
114 #include <linux/rtmutex.h>
115 #include <linux/reciprocal_div.h>
116 #include <linux/debugobjects.h>
117 #include <linux/kmemcheck.h>
119 #include <asm/cacheflush.h>
120 #include <asm/tlbflush.h>
121 #include <asm/page.h>
124 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
125 * 0 for faster, smaller code (especially in the critical paths).
127 * STATS - 1 to collect stats for /proc/slabinfo.
128 * 0 for faster, smaller code (especially in the critical paths).
130 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
133 #ifdef CONFIG_DEBUG_SLAB
136 #define FORCED_DEBUG 1
140 #define FORCED_DEBUG 0
143 /* Shouldn't this be in a header file somewhere? */
144 #define BYTES_PER_WORD sizeof(void *)
145 #define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long))
147 #ifndef ARCH_KMALLOC_MINALIGN
149 * Enforce a minimum alignment for the kmalloc caches.
150 * Usually, the kmalloc caches are cache_line_size() aligned, except when
151 * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
152 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
153 * alignment larger than the alignment of a 64-bit integer.
154 * ARCH_KMALLOC_MINALIGN allows that.
155 * Note that increasing this value may disable some debug features.
157 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
160 #ifndef ARCH_SLAB_MINALIGN
162 * Enforce a minimum alignment for all caches.
163 * Intended for archs that get misalignment faults even for BYTES_PER_WORD
164 * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
165 * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
166 * some debug features.
168 #define ARCH_SLAB_MINALIGN 0
171 #ifndef ARCH_KMALLOC_FLAGS
172 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
175 /* Legal flag mask for kmem_cache_create(). */
177 # define CREATE_MASK (SLAB_RED_ZONE | \
178 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
181 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
182 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
183 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
185 # define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
187 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
188 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
189 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
195 * Bufctl's are used for linking objs within a slab
198 * This implementation relies on "struct page" for locating the cache &
199 * slab an object belongs to.
200 * This allows the bufctl structure to be small (one int), but limits
201 * the number of objects a slab (not a cache) can contain when off-slab
202 * bufctls are used. The limit is the size of the largest general cache
203 * that does not use off-slab slabs.
204 * For 32bit archs with 4 kB pages, is this 56.
205 * This is not serious, as it is only for large objects, when it is unwise
206 * to have too many per slab.
207 * Note: This limit can be raised by introducing a general cache whose size
208 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
211 typedef unsigned int kmem_bufctl_t;
212 #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
213 #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
214 #define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2)
215 #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3)
220 * Manages the objs in a slab. Placed either at the beginning of mem allocated
221 * for a slab, or allocated from an general cache.
222 * Slabs are chained into three list: fully used, partial, fully free slabs.
225 struct list_head list;
226 unsigned long colouroff;
227 void *s_mem; /* including colour offset */
228 unsigned int inuse; /* num of objs active in slab */
230 unsigned short nodeid;
236 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
237 * arrange for kmem_freepages to be called via RCU. This is useful if
238 * we need to approach a kernel structure obliquely, from its address
239 * obtained without the usual locking. We can lock the structure to
240 * stabilize it and check it's still at the given address, only if we
241 * can be sure that the memory has not been meanwhile reused for some
242 * other kind of object (which our subsystem's lock might corrupt).
244 * rcu_read_lock before reading the address, then rcu_read_unlock after
245 * taking the spinlock within the structure expected at that address.
247 * We assume struct slab_rcu can overlay struct slab when destroying.
250 struct rcu_head head;
251 struct kmem_cache *cachep;
259 * - LIFO ordering, to hand out cache-warm objects from _alloc
260 * - reduce the number of linked list operations
261 * - reduce spinlock operations
263 * The limit is stored in the per-cpu structure to reduce the data cache
270 unsigned int batchcount;
271 unsigned int touched;
274 * Must have this definition in here for the proper
275 * alignment of array_cache. Also simplifies accessing
281 * bootstrap: The caches do not work without cpuarrays anymore, but the
282 * cpuarrays are allocated from the generic caches...
284 #define BOOT_CPUCACHE_ENTRIES 1
285 struct arraycache_init {
286 struct array_cache cache;
287 void *entries[BOOT_CPUCACHE_ENTRIES];
291 * The slab lists for all objects.
294 struct list_head slabs_partial; /* partial list first, better asm code */
295 struct list_head slabs_full;
296 struct list_head slabs_free;
297 unsigned long free_objects;
298 unsigned int free_limit;
299 unsigned int colour_next; /* Per-node cache coloring */
300 spinlock_t list_lock;
301 struct array_cache *shared; /* shared per node */
302 struct array_cache **alien; /* on other nodes */
303 unsigned long next_reap; /* updated without locking */
304 int free_touched; /* updated without locking */
308 * Need this for bootstrapping a per node allocator.
310 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
311 struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
312 #define CACHE_CACHE 0
313 #define SIZE_AC MAX_NUMNODES
314 #define SIZE_L3 (2 * MAX_NUMNODES)
316 static int drain_freelist(struct kmem_cache *cache,
317 struct kmem_list3 *l3, int tofree);
318 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
320 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
321 static void cache_reap(struct work_struct *unused);
324 * This function must be completely optimized away if a constant is passed to
325 * it. Mostly the same as what is in linux/slab.h except it returns an index.
327 static __always_inline int index_of(const size_t size)
329 extern void __bad_size(void);
331 if (__builtin_constant_p(size)) {
339 #include <linux/kmalloc_sizes.h>
347 static int slab_early_init = 1;
349 #define INDEX_AC index_of(sizeof(struct arraycache_init))
350 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
352 static void kmem_list3_init(struct kmem_list3 *parent)
354 INIT_LIST_HEAD(&parent->slabs_full);
355 INIT_LIST_HEAD(&parent->slabs_partial);
356 INIT_LIST_HEAD(&parent->slabs_free);
357 parent->shared = NULL;
358 parent->alien = NULL;
359 parent->colour_next = 0;
360 spin_lock_init(&parent->list_lock);
361 parent->free_objects = 0;
362 parent->free_touched = 0;
365 #define MAKE_LIST(cachep, listp, slab, nodeid) \
367 INIT_LIST_HEAD(listp); \
368 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
371 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
373 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
374 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
375 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
378 #define CFLGS_OFF_SLAB (0x80000000UL)
379 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
381 #define BATCHREFILL_LIMIT 16
383 * Optimization question: fewer reaps means less probability for unnessary
384 * cpucache drain/refill cycles.
386 * OTOH the cpuarrays can contain lots of objects,
387 * which could lock up otherwise freeable slabs.
389 #define REAPTIMEOUT_CPUC (2*HZ)
390 #define REAPTIMEOUT_LIST3 (4*HZ)
393 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
394 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
395 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
396 #define STATS_INC_GROWN(x) ((x)->grown++)
397 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
398 #define STATS_SET_HIGH(x) \
400 if ((x)->num_active > (x)->high_mark) \
401 (x)->high_mark = (x)->num_active; \
403 #define STATS_INC_ERR(x) ((x)->errors++)
404 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
405 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
406 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
407 #define STATS_SET_FREEABLE(x, i) \
409 if ((x)->max_freeable < i) \
410 (x)->max_freeable = i; \
412 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
413 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
414 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
415 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
417 #define STATS_INC_ACTIVE(x) do { } while (0)
418 #define STATS_DEC_ACTIVE(x) do { } while (0)
419 #define STATS_INC_ALLOCED(x) do { } while (0)
420 #define STATS_INC_GROWN(x) do { } while (0)
421 #define STATS_ADD_REAPED(x,y) do { } while (0)
422 #define STATS_SET_HIGH(x) do { } while (0)
423 #define STATS_INC_ERR(x) do { } while (0)
424 #define STATS_INC_NODEALLOCS(x) do { } while (0)
425 #define STATS_INC_NODEFREES(x) do { } while (0)
426 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
427 #define STATS_SET_FREEABLE(x, i) do { } while (0)
428 #define STATS_INC_ALLOCHIT(x) do { } while (0)
429 #define STATS_INC_ALLOCMISS(x) do { } while (0)
430 #define STATS_INC_FREEHIT(x) do { } while (0)
431 #define STATS_INC_FREEMISS(x) do { } while (0)
437 * memory layout of objects:
439 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
440 * the end of an object is aligned with the end of the real
441 * allocation. Catches writes behind the end of the allocation.
442 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
444 * cachep->obj_offset: The real object.
445 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
446 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
447 * [BYTES_PER_WORD long]
449 static int obj_offset(struct kmem_cache *cachep)
451 return cachep->obj_offset;
454 static int obj_size(struct kmem_cache *cachep)
456 return cachep->obj_size;
459 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
461 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
462 return (unsigned long long*) (objp + obj_offset(cachep) -
463 sizeof(unsigned long long));
466 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
468 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
469 if (cachep->flags & SLAB_STORE_USER)
470 return (unsigned long long *)(objp + cachep->buffer_size -
471 sizeof(unsigned long long) -
473 return (unsigned long long *) (objp + cachep->buffer_size -
474 sizeof(unsigned long long));
477 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
479 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
480 return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
485 #define obj_offset(x) 0
486 #define obj_size(cachep) (cachep->buffer_size)
487 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
488 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
489 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
493 #ifdef CONFIG_KMEMTRACE
494 size_t slab_buffer_size(struct kmem_cache *cachep)
496 return cachep->buffer_size;
498 EXPORT_SYMBOL(slab_buffer_size);
502 * Do not go above this order unless 0 objects fit into the slab.
504 #define BREAK_GFP_ORDER_HI 1
505 #define BREAK_GFP_ORDER_LO 0
506 static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
509 * Functions for storing/retrieving the cachep and or slab from the page
510 * allocator. These are used to find the slab an obj belongs to. With kfree(),
511 * these are used to find the cache which an obj belongs to.
513 static inline void page_set_cache(struct page *page, struct kmem_cache *cache)
515 page->lru.next = (struct list_head *)cache;
518 static inline struct kmem_cache *page_get_cache(struct page *page)
520 page = compound_head(page);
521 BUG_ON(!PageSlab(page));
522 return (struct kmem_cache *)page->lru.next;
525 static inline void page_set_slab(struct page *page, struct slab *slab)
527 page->lru.prev = (struct list_head *)slab;
530 static inline struct slab *page_get_slab(struct page *page)
532 BUG_ON(!PageSlab(page));
533 return (struct slab *)page->lru.prev;
536 static inline struct kmem_cache *virt_to_cache(const void *obj)
538 struct page *page = virt_to_head_page(obj);
539 return page_get_cache(page);
542 static inline struct slab *virt_to_slab(const void *obj)
544 struct page *page = virt_to_head_page(obj);
545 return page_get_slab(page);
548 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
551 return slab->s_mem + cache->buffer_size * idx;
555 * We want to avoid an expensive divide : (offset / cache->buffer_size)
556 * Using the fact that buffer_size is a constant for a particular cache,
557 * we can replace (offset / cache->buffer_size) by
558 * reciprocal_divide(offset, cache->reciprocal_buffer_size)
560 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
561 const struct slab *slab, void *obj)
563 u32 offset = (obj - slab->s_mem);
564 return reciprocal_divide(offset, cache->reciprocal_buffer_size);
568 * These are the default caches for kmalloc. Custom caches can have other sizes.
570 struct cache_sizes malloc_sizes[] = {
571 #define CACHE(x) { .cs_size = (x) },
572 #include <linux/kmalloc_sizes.h>
576 EXPORT_SYMBOL(malloc_sizes);
578 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
584 static struct cache_names __initdata cache_names[] = {
585 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
586 #include <linux/kmalloc_sizes.h>
591 static struct arraycache_init initarray_cache __initdata =
592 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
593 static struct arraycache_init initarray_generic =
594 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
596 /* internal cache of cache description objs */
597 static struct kmem_cache cache_cache = {
599 .limit = BOOT_CPUCACHE_ENTRIES,
601 .buffer_size = sizeof(struct kmem_cache),
602 .name = "kmem_cache",
605 #define BAD_ALIEN_MAGIC 0x01020304ul
607 #ifdef CONFIG_LOCKDEP
610 * Slab sometimes uses the kmalloc slabs to store the slab headers
611 * for other slabs "off slab".
612 * The locking for this is tricky in that it nests within the locks
613 * of all other slabs in a few places; to deal with this special
614 * locking we put on-slab caches into a separate lock-class.
616 * We set lock class for alien array caches which are up during init.
617 * The lock annotation will be lost if all cpus of a node goes down and
618 * then comes back up during hotplug
620 static struct lock_class_key on_slab_l3_key;
621 static struct lock_class_key on_slab_alc_key;
623 static inline void init_lock_keys(void)
627 struct cache_sizes *s = malloc_sizes;
629 while (s->cs_size != ULONG_MAX) {
631 struct array_cache **alc;
633 struct kmem_list3 *l3 = s->cs_cachep->nodelists[q];
634 if (!l3 || OFF_SLAB(s->cs_cachep))
636 lockdep_set_class(&l3->list_lock, &on_slab_l3_key);
639 * FIXME: This check for BAD_ALIEN_MAGIC
640 * should go away when common slab code is taught to
641 * work even without alien caches.
642 * Currently, non NUMA code returns BAD_ALIEN_MAGIC
643 * for alloc_alien_cache,
645 if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
649 lockdep_set_class(&alc[r]->lock,
657 static inline void init_lock_keys(void)
663 * Guard access to the cache-chain.
665 static DEFINE_MUTEX(cache_chain_mutex);
666 static struct list_head cache_chain;
669 * chicken and egg problem: delay the per-cpu array allocation
670 * until the general caches are up.
680 * used by boot code to determine if it can use slab based allocator
682 int slab_is_available(void)
684 return g_cpucache_up == FULL;
687 static DEFINE_PER_CPU(struct delayed_work, reap_work);
689 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
691 return cachep->array[smp_processor_id()];
694 static inline struct kmem_cache *__find_general_cachep(size_t size,
697 struct cache_sizes *csizep = malloc_sizes;
700 /* This happens if someone tries to call
701 * kmem_cache_create(), or __kmalloc(), before
702 * the generic caches are initialized.
704 BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
707 return ZERO_SIZE_PTR;
709 while (size > csizep->cs_size)
713 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
714 * has cs_{dma,}cachep==NULL. Thus no special case
715 * for large kmalloc calls required.
717 #ifdef CONFIG_ZONE_DMA
718 if (unlikely(gfpflags & GFP_DMA))
719 return csizep->cs_dmacachep;
721 return csizep->cs_cachep;
724 static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
726 return __find_general_cachep(size, gfpflags);
729 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
731 return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
735 * Calculate the number of objects and left-over bytes for a given buffer size.
737 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
738 size_t align, int flags, size_t *left_over,
743 size_t slab_size = PAGE_SIZE << gfporder;
746 * The slab management structure can be either off the slab or
747 * on it. For the latter case, the memory allocated for a
751 * - One kmem_bufctl_t for each object
752 * - Padding to respect alignment of @align
753 * - @buffer_size bytes for each object
755 * If the slab management structure is off the slab, then the
756 * alignment will already be calculated into the size. Because
757 * the slabs are all pages aligned, the objects will be at the
758 * correct alignment when allocated.
760 if (flags & CFLGS_OFF_SLAB) {
762 nr_objs = slab_size / buffer_size;
764 if (nr_objs > SLAB_LIMIT)
765 nr_objs = SLAB_LIMIT;
768 * Ignore padding for the initial guess. The padding
769 * is at most @align-1 bytes, and @buffer_size is at
770 * least @align. In the worst case, this result will
771 * be one greater than the number of objects that fit
772 * into the memory allocation when taking the padding
775 nr_objs = (slab_size - sizeof(struct slab)) /
776 (buffer_size + sizeof(kmem_bufctl_t));
779 * This calculated number will be either the right
780 * amount, or one greater than what we want.
782 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
786 if (nr_objs > SLAB_LIMIT)
787 nr_objs = SLAB_LIMIT;
789 mgmt_size = slab_mgmt_size(nr_objs, align);
792 *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
795 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
797 static void __slab_error(const char *function, struct kmem_cache *cachep,
800 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
801 function, cachep->name, msg);
806 * By default on NUMA we use alien caches to stage the freeing of
807 * objects allocated from other nodes. This causes massive memory
808 * inefficiencies when using fake NUMA setup to split memory into a
809 * large number of small nodes, so it can be disabled on the command
813 static int use_alien_caches __read_mostly = 1;
814 static int numa_platform __read_mostly = 1;
815 static int __init noaliencache_setup(char *s)
817 use_alien_caches = 0;
820 __setup("noaliencache", noaliencache_setup);
824 * Special reaping functions for NUMA systems called from cache_reap().
825 * These take care of doing round robin flushing of alien caches (containing
826 * objects freed on different nodes from which they were allocated) and the
827 * flushing of remote pcps by calling drain_node_pages.
829 static DEFINE_PER_CPU(unsigned long, reap_node);
831 static void init_reap_node(int cpu)
835 node = next_node(cpu_to_node(cpu), node_online_map);
836 if (node == MAX_NUMNODES)
837 node = first_node(node_online_map);
839 per_cpu(reap_node, cpu) = node;
842 static void next_reap_node(void)
844 int node = __get_cpu_var(reap_node);
846 node = next_node(node, node_online_map);
847 if (unlikely(node >= MAX_NUMNODES))
848 node = first_node(node_online_map);
849 __get_cpu_var(reap_node) = node;
853 #define init_reap_node(cpu) do { } while (0)
854 #define next_reap_node(void) do { } while (0)
858 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
859 * via the workqueue/eventd.
860 * Add the CPU number into the expiration time to minimize the possibility of
861 * the CPUs getting into lockstep and contending for the global cache chain
864 static void __cpuinit start_cpu_timer(int cpu)
866 struct delayed_work *reap_work = &per_cpu(reap_work, cpu);
869 * When this gets called from do_initcalls via cpucache_init(),
870 * init_workqueues() has already run, so keventd will be setup
873 if (keventd_up() && reap_work->work.func == NULL) {
875 INIT_DELAYED_WORK(reap_work, cache_reap);
876 schedule_delayed_work_on(cpu, reap_work,
877 __round_jiffies_relative(HZ, cpu));
881 static struct array_cache *alloc_arraycache(int node, int entries,
882 int batchcount, gfp_t gfp)
884 int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
885 struct array_cache *nc = NULL;
887 nc = kmalloc_node(memsize, gfp, node);
889 * The array_cache structures contain pointers to free object.
890 * However, when such objects are allocated or transfered to another
891 * cache the pointers are not cleared and they could be counted as
892 * valid references during a kmemleak scan. Therefore, kmemleak must
893 * not scan such objects.
895 kmemleak_no_scan(nc);
899 nc->batchcount = batchcount;
901 spin_lock_init(&nc->lock);
907 * Transfer objects in one arraycache to another.
908 * Locking must be handled by the caller.
910 * Return the number of entries transferred.
912 static int transfer_objects(struct array_cache *to,
913 struct array_cache *from, unsigned int max)
915 /* Figure out how many entries to transfer */
916 int nr = min(min(from->avail, max), to->limit - to->avail);
921 memcpy(to->entry + to->avail, from->entry + from->avail -nr,
932 #define drain_alien_cache(cachep, alien) do { } while (0)
933 #define reap_alien(cachep, l3) do { } while (0)
935 static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
937 return (struct array_cache **)BAD_ALIEN_MAGIC;
940 static inline void free_alien_cache(struct array_cache **ac_ptr)
944 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
949 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
955 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
956 gfp_t flags, int nodeid)
961 #else /* CONFIG_NUMA */
963 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
964 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
966 static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
968 struct array_cache **ac_ptr;
969 int memsize = sizeof(void *) * nr_node_ids;
974 ac_ptr = kmalloc_node(memsize, gfp, node);
977 if (i == node || !node_online(i)) {
981 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
983 for (i--; i >= 0; i--)
993 static void free_alien_cache(struct array_cache **ac_ptr)
1004 static void __drain_alien_cache(struct kmem_cache *cachep,
1005 struct array_cache *ac, int node)
1007 struct kmem_list3 *rl3 = cachep->nodelists[node];
1010 spin_lock(&rl3->list_lock);
1012 * Stuff objects into the remote nodes shared array first.
1013 * That way we could avoid the overhead of putting the objects
1014 * into the free lists and getting them back later.
1017 transfer_objects(rl3->shared, ac, ac->limit);
1019 free_block(cachep, ac->entry, ac->avail, node);
1021 spin_unlock(&rl3->list_lock);
1026 * Called from cache_reap() to regularly drain alien caches round robin.
1028 static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
1030 int node = __get_cpu_var(reap_node);
1033 struct array_cache *ac = l3->alien[node];
1035 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1036 __drain_alien_cache(cachep, ac, node);
1037 spin_unlock_irq(&ac->lock);
1042 static void drain_alien_cache(struct kmem_cache *cachep,
1043 struct array_cache **alien)
1046 struct array_cache *ac;
1047 unsigned long flags;
1049 for_each_online_node(i) {
1052 spin_lock_irqsave(&ac->lock, flags);
1053 __drain_alien_cache(cachep, ac, i);
1054 spin_unlock_irqrestore(&ac->lock, flags);
1059 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1061 struct slab *slabp = virt_to_slab(objp);
1062 int nodeid = slabp->nodeid;
1063 struct kmem_list3 *l3;
1064 struct array_cache *alien = NULL;
1067 node = numa_node_id();
1070 * Make sure we are not freeing a object from another node to the array
1071 * cache on this cpu.
1073 if (likely(slabp->nodeid == node))
1076 l3 = cachep->nodelists[node];
1077 STATS_INC_NODEFREES(cachep);
1078 if (l3->alien && l3->alien[nodeid]) {
1079 alien = l3->alien[nodeid];
1080 spin_lock(&alien->lock);
1081 if (unlikely(alien->avail == alien->limit)) {
1082 STATS_INC_ACOVERFLOW(cachep);
1083 __drain_alien_cache(cachep, alien, nodeid);
1085 alien->entry[alien->avail++] = objp;
1086 spin_unlock(&alien->lock);
1088 spin_lock(&(cachep->nodelists[nodeid])->list_lock);
1089 free_block(cachep, &objp, 1, nodeid);
1090 spin_unlock(&(cachep->nodelists[nodeid])->list_lock);
1096 static void __cpuinit cpuup_canceled(long cpu)
1098 struct kmem_cache *cachep;
1099 struct kmem_list3 *l3 = NULL;
1100 int node = cpu_to_node(cpu);
1101 const struct cpumask *mask = cpumask_of_node(node);
1103 list_for_each_entry(cachep, &cache_chain, next) {
1104 struct array_cache *nc;
1105 struct array_cache *shared;
1106 struct array_cache **alien;
1108 /* cpu is dead; no one can alloc from it. */
1109 nc = cachep->array[cpu];
1110 cachep->array[cpu] = NULL;
1111 l3 = cachep->nodelists[node];
1114 goto free_array_cache;
1116 spin_lock_irq(&l3->list_lock);
1118 /* Free limit for this kmem_list3 */
1119 l3->free_limit -= cachep->batchcount;
1121 free_block(cachep, nc->entry, nc->avail, node);
1123 if (!cpus_empty(*mask)) {
1124 spin_unlock_irq(&l3->list_lock);
1125 goto free_array_cache;
1128 shared = l3->shared;
1130 free_block(cachep, shared->entry,
1131 shared->avail, node);
1138 spin_unlock_irq(&l3->list_lock);
1142 drain_alien_cache(cachep, alien);
1143 free_alien_cache(alien);
1149 * In the previous loop, all the objects were freed to
1150 * the respective cache's slabs, now we can go ahead and
1151 * shrink each nodelist to its limit.
1153 list_for_each_entry(cachep, &cache_chain, next) {
1154 l3 = cachep->nodelists[node];
1157 drain_freelist(cachep, l3, l3->free_objects);
1161 static int __cpuinit cpuup_prepare(long cpu)
1163 struct kmem_cache *cachep;
1164 struct kmem_list3 *l3 = NULL;
1165 int node = cpu_to_node(cpu);
1166 const int memsize = sizeof(struct kmem_list3);
1169 * We need to do this right in the beginning since
1170 * alloc_arraycache's are going to use this list.
1171 * kmalloc_node allows us to add the slab to the right
1172 * kmem_list3 and not this cpu's kmem_list3
1175 list_for_each_entry(cachep, &cache_chain, next) {
1177 * Set up the size64 kmemlist for cpu before we can
1178 * begin anything. Make sure some other cpu on this
1179 * node has not already allocated this
1181 if (!cachep->nodelists[node]) {
1182 l3 = kmalloc_node(memsize, GFP_KERNEL, node);
1185 kmem_list3_init(l3);
1186 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1187 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1190 * The l3s don't come and go as CPUs come and
1191 * go. cache_chain_mutex is sufficient
1194 cachep->nodelists[node] = l3;
1197 spin_lock_irq(&cachep->nodelists[node]->list_lock);
1198 cachep->nodelists[node]->free_limit =
1199 (1 + nr_cpus_node(node)) *
1200 cachep->batchcount + cachep->num;
1201 spin_unlock_irq(&cachep->nodelists[node]->list_lock);
1205 * Now we can go ahead with allocating the shared arrays and
1208 list_for_each_entry(cachep, &cache_chain, next) {
1209 struct array_cache *nc;
1210 struct array_cache *shared = NULL;
1211 struct array_cache **alien = NULL;
1213 nc = alloc_arraycache(node, cachep->limit,
1214 cachep->batchcount, GFP_KERNEL);
1217 if (cachep->shared) {
1218 shared = alloc_arraycache(node,
1219 cachep->shared * cachep->batchcount,
1220 0xbaadf00d, GFP_KERNEL);
1226 if (use_alien_caches) {
1227 alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
1234 cachep->array[cpu] = nc;
1235 l3 = cachep->nodelists[node];
1238 spin_lock_irq(&l3->list_lock);
1241 * We are serialised from CPU_DEAD or
1242 * CPU_UP_CANCELLED by the cpucontrol lock
1244 l3->shared = shared;
1253 spin_unlock_irq(&l3->list_lock);
1255 free_alien_cache(alien);
1259 cpuup_canceled(cpu);
1263 static int __cpuinit cpuup_callback(struct notifier_block *nfb,
1264 unsigned long action, void *hcpu)
1266 long cpu = (long)hcpu;
1270 case CPU_UP_PREPARE:
1271 case CPU_UP_PREPARE_FROZEN:
1272 mutex_lock(&cache_chain_mutex);
1273 err = cpuup_prepare(cpu);
1274 mutex_unlock(&cache_chain_mutex);
1277 case CPU_ONLINE_FROZEN:
1278 start_cpu_timer(cpu);
1280 #ifdef CONFIG_HOTPLUG_CPU
1281 case CPU_DOWN_PREPARE:
1282 case CPU_DOWN_PREPARE_FROZEN:
1284 * Shutdown cache reaper. Note that the cache_chain_mutex is
1285 * held so that if cache_reap() is invoked it cannot do
1286 * anything expensive but will only modify reap_work
1287 * and reschedule the timer.
1289 cancel_rearming_delayed_work(&per_cpu(reap_work, cpu));
1290 /* Now the cache_reaper is guaranteed to be not running. */
1291 per_cpu(reap_work, cpu).work.func = NULL;
1293 case CPU_DOWN_FAILED:
1294 case CPU_DOWN_FAILED_FROZEN:
1295 start_cpu_timer(cpu);
1298 case CPU_DEAD_FROZEN:
1300 * Even if all the cpus of a node are down, we don't free the
1301 * kmem_list3 of any cache. This to avoid a race between
1302 * cpu_down, and a kmalloc allocation from another cpu for
1303 * memory from the node of the cpu going down. The list3
1304 * structure is usually allocated from kmem_cache_create() and
1305 * gets destroyed at kmem_cache_destroy().
1309 case CPU_UP_CANCELED:
1310 case CPU_UP_CANCELED_FROZEN:
1311 mutex_lock(&cache_chain_mutex);
1312 cpuup_canceled(cpu);
1313 mutex_unlock(&cache_chain_mutex);
1316 return err ? NOTIFY_BAD : NOTIFY_OK;
1319 static struct notifier_block __cpuinitdata cpucache_notifier = {
1320 &cpuup_callback, NULL, 0
1324 * swap the static kmem_list3 with kmalloced memory
1326 static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
1329 struct kmem_list3 *ptr;
1331 ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_NOWAIT, nodeid);
1334 memcpy(ptr, list, sizeof(struct kmem_list3));
1336 * Do not assume that spinlocks can be initialized via memcpy:
1338 spin_lock_init(&ptr->list_lock);
1340 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1341 cachep->nodelists[nodeid] = ptr;
1345 * For setting up all the kmem_list3s for cache whose buffer_size is same as
1346 * size of kmem_list3.
1348 static void __init set_up_list3s(struct kmem_cache *cachep, int index)
1352 for_each_online_node(node) {
1353 cachep->nodelists[node] = &initkmem_list3[index + node];
1354 cachep->nodelists[node]->next_reap = jiffies +
1356 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1361 * Initialisation. Called after the page allocator have been initialised and
1362 * before smp_init().
1364 void __init kmem_cache_init(void)
1367 struct cache_sizes *sizes;
1368 struct cache_names *names;
1373 if (num_possible_nodes() == 1) {
1374 use_alien_caches = 0;
1378 for (i = 0; i < NUM_INIT_LISTS; i++) {
1379 kmem_list3_init(&initkmem_list3[i]);
1380 if (i < MAX_NUMNODES)
1381 cache_cache.nodelists[i] = NULL;
1383 set_up_list3s(&cache_cache, CACHE_CACHE);
1386 * Fragmentation resistance on low memory - only use bigger
1387 * page orders on machines with more than 32MB of memory.
1389 if (num_physpages > (32 << 20) >> PAGE_SHIFT)
1390 slab_break_gfp_order = BREAK_GFP_ORDER_HI;
1392 /* Bootstrap is tricky, because several objects are allocated
1393 * from caches that do not exist yet:
1394 * 1) initialize the cache_cache cache: it contains the struct
1395 * kmem_cache structures of all caches, except cache_cache itself:
1396 * cache_cache is statically allocated.
1397 * Initially an __init data area is used for the head array and the
1398 * kmem_list3 structures, it's replaced with a kmalloc allocated
1399 * array at the end of the bootstrap.
1400 * 2) Create the first kmalloc cache.
1401 * The struct kmem_cache for the new cache is allocated normally.
1402 * An __init data area is used for the head array.
1403 * 3) Create the remaining kmalloc caches, with minimally sized
1405 * 4) Replace the __init data head arrays for cache_cache and the first
1406 * kmalloc cache with kmalloc allocated arrays.
1407 * 5) Replace the __init data for kmem_list3 for cache_cache and
1408 * the other cache's with kmalloc allocated memory.
1409 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1412 node = numa_node_id();
1414 /* 1) create the cache_cache */
1415 INIT_LIST_HEAD(&cache_chain);
1416 list_add(&cache_cache.next, &cache_chain);
1417 cache_cache.colour_off = cache_line_size();
1418 cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
1419 cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node];
1422 * struct kmem_cache size depends on nr_node_ids, which
1423 * can be less than MAX_NUMNODES.
1425 cache_cache.buffer_size = offsetof(struct kmem_cache, nodelists) +
1426 nr_node_ids * sizeof(struct kmem_list3 *);
1428 cache_cache.obj_size = cache_cache.buffer_size;
1430 cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
1432 cache_cache.reciprocal_buffer_size =
1433 reciprocal_value(cache_cache.buffer_size);
1435 for (order = 0; order < MAX_ORDER; order++) {
1436 cache_estimate(order, cache_cache.buffer_size,
1437 cache_line_size(), 0, &left_over, &cache_cache.num);
1438 if (cache_cache.num)
1441 BUG_ON(!cache_cache.num);
1442 cache_cache.gfporder = order;
1443 cache_cache.colour = left_over / cache_cache.colour_off;
1444 cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
1445 sizeof(struct slab), cache_line_size());
1447 /* 2+3) create the kmalloc caches */
1448 sizes = malloc_sizes;
1449 names = cache_names;
1452 * Initialize the caches that provide memory for the array cache and the
1453 * kmem_list3 structures first. Without this, further allocations will
1457 sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name,
1458 sizes[INDEX_AC].cs_size,
1459 ARCH_KMALLOC_MINALIGN,
1460 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1463 if (INDEX_AC != INDEX_L3) {
1464 sizes[INDEX_L3].cs_cachep =
1465 kmem_cache_create(names[INDEX_L3].name,
1466 sizes[INDEX_L3].cs_size,
1467 ARCH_KMALLOC_MINALIGN,
1468 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1472 slab_early_init = 0;
1474 while (sizes->cs_size != ULONG_MAX) {
1476 * For performance, all the general caches are L1 aligned.
1477 * This should be particularly beneficial on SMP boxes, as it
1478 * eliminates "false sharing".
1479 * Note for systems short on memory removing the alignment will
1480 * allow tighter packing of the smaller caches.
1482 if (!sizes->cs_cachep) {
1483 sizes->cs_cachep = kmem_cache_create(names->name,
1485 ARCH_KMALLOC_MINALIGN,
1486 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1489 #ifdef CONFIG_ZONE_DMA
1490 sizes->cs_dmacachep = kmem_cache_create(
1493 ARCH_KMALLOC_MINALIGN,
1494 ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
1501 /* 4) Replace the bootstrap head arrays */
1503 struct array_cache *ptr;
1505 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1507 BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
1508 memcpy(ptr, cpu_cache_get(&cache_cache),
1509 sizeof(struct arraycache_init));
1511 * Do not assume that spinlocks can be initialized via memcpy:
1513 spin_lock_init(&ptr->lock);
1515 cache_cache.array[smp_processor_id()] = ptr;
1517 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1519 BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
1520 != &initarray_generic.cache);
1521 memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
1522 sizeof(struct arraycache_init));
1524 * Do not assume that spinlocks can be initialized via memcpy:
1526 spin_lock_init(&ptr->lock);
1528 malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
1531 /* 5) Replace the bootstrap kmem_list3's */
1535 for_each_online_node(nid) {
1536 init_list(&cache_cache, &initkmem_list3[CACHE_CACHE + nid], nid);
1538 init_list(malloc_sizes[INDEX_AC].cs_cachep,
1539 &initkmem_list3[SIZE_AC + nid], nid);
1541 if (INDEX_AC != INDEX_L3) {
1542 init_list(malloc_sizes[INDEX_L3].cs_cachep,
1543 &initkmem_list3[SIZE_L3 + nid], nid);
1548 /* 6) resize the head arrays to their final sizes */
1550 struct kmem_cache *cachep;
1551 mutex_lock(&cache_chain_mutex);
1552 list_for_each_entry(cachep, &cache_chain, next)
1553 if (enable_cpucache(cachep, GFP_NOWAIT))
1555 mutex_unlock(&cache_chain_mutex);
1558 /* Annotate slab for lockdep -- annotate the malloc caches */
1563 g_cpucache_up = FULL;
1566 * Register a cpu startup notifier callback that initializes
1567 * cpu_cache_get for all new cpus
1569 register_cpu_notifier(&cpucache_notifier);
1572 * The reap timers are started later, with a module init call: That part
1573 * of the kernel is not yet operational.
1577 static int __init cpucache_init(void)
1582 * Register the timers that return unneeded pages to the page allocator
1584 for_each_online_cpu(cpu)
1585 start_cpu_timer(cpu);
1588 __initcall(cpucache_init);
1591 * Interface to system's page allocator. No need to hold the cache-lock.
1593 * If we requested dmaable memory, we will get it. Even if we
1594 * did not request dmaable memory, we might get it, but that
1595 * would be relatively rare and ignorable.
1597 static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
1605 * Nommu uses slab's for process anonymous memory allocations, and thus
1606 * requires __GFP_COMP to properly refcount higher order allocations
1608 flags |= __GFP_COMP;
1611 flags |= cachep->gfpflags;
1612 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1613 flags |= __GFP_RECLAIMABLE;
1615 page = alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1619 nr_pages = (1 << cachep->gfporder);
1620 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1621 add_zone_page_state(page_zone(page),
1622 NR_SLAB_RECLAIMABLE, nr_pages);
1624 add_zone_page_state(page_zone(page),
1625 NR_SLAB_UNRECLAIMABLE, nr_pages);
1626 for (i = 0; i < nr_pages; i++)
1627 __SetPageSlab(page + i);
1629 if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1630 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1633 kmemcheck_mark_uninitialized_pages(page, nr_pages);
1635 kmemcheck_mark_unallocated_pages(page, nr_pages);
1638 return page_address(page);
1642 * Interface to system's page release.
1644 static void kmem_freepages(struct kmem_cache *cachep, void *addr)
1646 unsigned long i = (1 << cachep->gfporder);
1647 struct page *page = virt_to_page(addr);
1648 const unsigned long nr_freed = i;
1650 kmemcheck_free_shadow(page, cachep->gfporder);
1652 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1653 sub_zone_page_state(page_zone(page),
1654 NR_SLAB_RECLAIMABLE, nr_freed);
1656 sub_zone_page_state(page_zone(page),
1657 NR_SLAB_UNRECLAIMABLE, nr_freed);
1659 BUG_ON(!PageSlab(page));
1660 __ClearPageSlab(page);
1663 if (current->reclaim_state)
1664 current->reclaim_state->reclaimed_slab += nr_freed;
1665 free_pages((unsigned long)addr, cachep->gfporder);
1668 static void kmem_rcu_free(struct rcu_head *head)
1670 struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
1671 struct kmem_cache *cachep = slab_rcu->cachep;
1673 kmem_freepages(cachep, slab_rcu->addr);
1674 if (OFF_SLAB(cachep))
1675 kmem_cache_free(cachep->slabp_cache, slab_rcu);
1680 #ifdef CONFIG_DEBUG_PAGEALLOC
1681 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1682 unsigned long caller)
1684 int size = obj_size(cachep);
1686 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1688 if (size < 5 * sizeof(unsigned long))
1691 *addr++ = 0x12345678;
1693 *addr++ = smp_processor_id();
1694 size -= 3 * sizeof(unsigned long);
1696 unsigned long *sptr = &caller;
1697 unsigned long svalue;
1699 while (!kstack_end(sptr)) {
1701 if (kernel_text_address(svalue)) {
1703 size -= sizeof(unsigned long);
1704 if (size <= sizeof(unsigned long))
1710 *addr++ = 0x87654321;
1714 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1716 int size = obj_size(cachep);
1717 addr = &((char *)addr)[obj_offset(cachep)];
1719 memset(addr, val, size);
1720 *(unsigned char *)(addr + size - 1) = POISON_END;
1723 static void dump_line(char *data, int offset, int limit)
1726 unsigned char error = 0;
1729 printk(KERN_ERR "%03x:", offset);
1730 for (i = 0; i < limit; i++) {
1731 if (data[offset + i] != POISON_FREE) {
1732 error = data[offset + i];
1735 printk(" %02x", (unsigned char)data[offset + i]);
1739 if (bad_count == 1) {
1740 error ^= POISON_FREE;
1741 if (!(error & (error - 1))) {
1742 printk(KERN_ERR "Single bit error detected. Probably "
1745 printk(KERN_ERR "Run memtest86+ or a similar memory "
1748 printk(KERN_ERR "Run a memory test tool.\n");
1757 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1762 if (cachep->flags & SLAB_RED_ZONE) {
1763 printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n",
1764 *dbg_redzone1(cachep, objp),
1765 *dbg_redzone2(cachep, objp));
1768 if (cachep->flags & SLAB_STORE_USER) {
1769 printk(KERN_ERR "Last user: [<%p>]",
1770 *dbg_userword(cachep, objp));
1771 print_symbol("(%s)",
1772 (unsigned long)*dbg_userword(cachep, objp));
1775 realobj = (char *)objp + obj_offset(cachep);
1776 size = obj_size(cachep);
1777 for (i = 0; i < size && lines; i += 16, lines--) {
1780 if (i + limit > size)
1782 dump_line(realobj, i, limit);
1786 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1792 realobj = (char *)objp + obj_offset(cachep);
1793 size = obj_size(cachep);
1795 for (i = 0; i < size; i++) {
1796 char exp = POISON_FREE;
1799 if (realobj[i] != exp) {
1805 "Slab corruption: %s start=%p, len=%d\n",
1806 cachep->name, realobj, size);
1807 print_objinfo(cachep, objp, 0);
1809 /* Hexdump the affected line */
1812 if (i + limit > size)
1814 dump_line(realobj, i, limit);
1817 /* Limit to 5 lines */
1823 /* Print some data about the neighboring objects, if they
1826 struct slab *slabp = virt_to_slab(objp);
1829 objnr = obj_to_index(cachep, slabp, objp);
1831 objp = index_to_obj(cachep, slabp, objnr - 1);
1832 realobj = (char *)objp + obj_offset(cachep);
1833 printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1835 print_objinfo(cachep, objp, 2);
1837 if (objnr + 1 < cachep->num) {
1838 objp = index_to_obj(cachep, slabp, objnr + 1);
1839 realobj = (char *)objp + obj_offset(cachep);
1840 printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1842 print_objinfo(cachep, objp, 2);
1849 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
1852 for (i = 0; i < cachep->num; i++) {
1853 void *objp = index_to_obj(cachep, slabp, i);
1855 if (cachep->flags & SLAB_POISON) {
1856 #ifdef CONFIG_DEBUG_PAGEALLOC
1857 if (cachep->buffer_size % PAGE_SIZE == 0 &&
1859 kernel_map_pages(virt_to_page(objp),
1860 cachep->buffer_size / PAGE_SIZE, 1);
1862 check_poison_obj(cachep, objp);
1864 check_poison_obj(cachep, objp);
1867 if (cachep->flags & SLAB_RED_ZONE) {
1868 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1869 slab_error(cachep, "start of a freed object "
1871 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1872 slab_error(cachep, "end of a freed object "
1878 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
1884 * slab_destroy - destroy and release all objects in a slab
1885 * @cachep: cache pointer being destroyed
1886 * @slabp: slab pointer being destroyed
1888 * Destroy all the objs in a slab, and release the mem back to the system.
1889 * Before calling the slab must have been unlinked from the cache. The
1890 * cache-lock is not held/needed.
1892 static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
1894 void *addr = slabp->s_mem - slabp->colouroff;
1896 slab_destroy_debugcheck(cachep, slabp);
1897 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
1898 struct slab_rcu *slab_rcu;
1900 slab_rcu = (struct slab_rcu *)slabp;
1901 slab_rcu->cachep = cachep;
1902 slab_rcu->addr = addr;
1903 call_rcu(&slab_rcu->head, kmem_rcu_free);
1905 kmem_freepages(cachep, addr);
1906 if (OFF_SLAB(cachep))
1907 kmem_cache_free(cachep->slabp_cache, slabp);
1911 static void __kmem_cache_destroy(struct kmem_cache *cachep)
1914 struct kmem_list3 *l3;
1916 for_each_online_cpu(i)
1917 kfree(cachep->array[i]);
1919 /* NUMA: free the list3 structures */
1920 for_each_online_node(i) {
1921 l3 = cachep->nodelists[i];
1924 free_alien_cache(l3->alien);
1928 kmem_cache_free(&cache_cache, cachep);
1933 * calculate_slab_order - calculate size (page order) of slabs
1934 * @cachep: pointer to the cache that is being created
1935 * @size: size of objects to be created in this cache.
1936 * @align: required alignment for the objects.
1937 * @flags: slab allocation flags
1939 * Also calculates the number of objects per slab.
1941 * This could be made much more intelligent. For now, try to avoid using
1942 * high order pages for slabs. When the gfp() functions are more friendly
1943 * towards high-order requests, this should be changed.
1945 static size_t calculate_slab_order(struct kmem_cache *cachep,
1946 size_t size, size_t align, unsigned long flags)
1948 unsigned long offslab_limit;
1949 size_t left_over = 0;
1952 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
1956 cache_estimate(gfporder, size, align, flags, &remainder, &num);
1960 if (flags & CFLGS_OFF_SLAB) {
1962 * Max number of objs-per-slab for caches which
1963 * use off-slab slabs. Needed to avoid a possible
1964 * looping condition in cache_grow().
1966 offslab_limit = size - sizeof(struct slab);
1967 offslab_limit /= sizeof(kmem_bufctl_t);
1969 if (num > offslab_limit)
1973 /* Found something acceptable - save it away */
1975 cachep->gfporder = gfporder;
1976 left_over = remainder;
1979 * A VFS-reclaimable slab tends to have most allocations
1980 * as GFP_NOFS and we really don't want to have to be allocating
1981 * higher-order pages when we are unable to shrink dcache.
1983 if (flags & SLAB_RECLAIM_ACCOUNT)
1987 * Large number of objects is good, but very large slabs are
1988 * currently bad for the gfp()s.
1990 if (gfporder >= slab_break_gfp_order)
1994 * Acceptable internal fragmentation?
1996 if (left_over * 8 <= (PAGE_SIZE << gfporder))
2002 static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
2004 if (g_cpucache_up == FULL)
2005 return enable_cpucache(cachep, gfp);
2007 if (g_cpucache_up == NONE) {
2009 * Note: the first kmem_cache_create must create the cache
2010 * that's used by kmalloc(24), otherwise the creation of
2011 * further caches will BUG().
2013 cachep->array[smp_processor_id()] = &initarray_generic.cache;
2016 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
2017 * the first cache, then we need to set up all its list3s,
2018 * otherwise the creation of further caches will BUG().
2020 set_up_list3s(cachep, SIZE_AC);
2021 if (INDEX_AC == INDEX_L3)
2022 g_cpucache_up = PARTIAL_L3;
2024 g_cpucache_up = PARTIAL_AC;
2026 cachep->array[smp_processor_id()] =
2027 kmalloc(sizeof(struct arraycache_init), gfp);
2029 if (g_cpucache_up == PARTIAL_AC) {
2030 set_up_list3s(cachep, SIZE_L3);
2031 g_cpucache_up = PARTIAL_L3;
2034 for_each_online_node(node) {
2035 cachep->nodelists[node] =
2036 kmalloc_node(sizeof(struct kmem_list3),
2038 BUG_ON(!cachep->nodelists[node]);
2039 kmem_list3_init(cachep->nodelists[node]);
2043 cachep->nodelists[numa_node_id()]->next_reap =
2044 jiffies + REAPTIMEOUT_LIST3 +
2045 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
2047 cpu_cache_get(cachep)->avail = 0;
2048 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
2049 cpu_cache_get(cachep)->batchcount = 1;
2050 cpu_cache_get(cachep)->touched = 0;
2051 cachep->batchcount = 1;
2052 cachep->limit = BOOT_CPUCACHE_ENTRIES;
2057 * kmem_cache_create - Create a cache.
2058 * @name: A string which is used in /proc/slabinfo to identify this cache.
2059 * @size: The size of objects to be created in this cache.
2060 * @align: The required alignment for the objects.
2061 * @flags: SLAB flags
2062 * @ctor: A constructor for the objects.
2064 * Returns a ptr to the cache on success, NULL on failure.
2065 * Cannot be called within a int, but can be interrupted.
2066 * The @ctor is run when new pages are allocated by the cache.
2068 * @name must be valid until the cache is destroyed. This implies that
2069 * the module calling this has to destroy the cache before getting unloaded.
2070 * Note that kmem_cache_name() is not guaranteed to return the same pointer,
2071 * therefore applications must manage it themselves.
2075 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2076 * to catch references to uninitialised memory.
2078 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2079 * for buffer overruns.
2081 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2082 * cacheline. This can be beneficial if you're counting cycles as closely
2086 kmem_cache_create (const char *name, size_t size, size_t align,
2087 unsigned long flags, void (*ctor)(void *))
2089 size_t left_over, slab_size, ralign;
2090 struct kmem_cache *cachep = NULL, *pc;
2094 * Sanity checks... these are all serious usage bugs.
2096 if (!name || in_interrupt() || (size < BYTES_PER_WORD) ||
2097 size > KMALLOC_MAX_SIZE) {
2098 printk(KERN_ERR "%s: Early error in slab %s\n", __func__,
2104 * We use cache_chain_mutex to ensure a consistent view of
2105 * cpu_online_mask as well. Please see cpuup_callback
2107 if (slab_is_available()) {
2109 mutex_lock(&cache_chain_mutex);
2112 list_for_each_entry(pc, &cache_chain, next) {
2117 * This happens when the module gets unloaded and doesn't
2118 * destroy its slab cache and no-one else reuses the vmalloc
2119 * area of the module. Print a warning.
2121 res = probe_kernel_address(pc->name, tmp);
2124 "SLAB: cache with size %d has lost its name\n",
2129 if (!strcmp(pc->name, name)) {
2131 "kmem_cache_create: duplicate cache %s\n", name);
2138 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
2141 * Enable redzoning and last user accounting, except for caches with
2142 * large objects, if the increased size would increase the object size
2143 * above the next power of two: caches with object sizes just above a
2144 * power of two have a significant amount of internal fragmentation.
2146 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2147 2 * sizeof(unsigned long long)))
2148 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2149 if (!(flags & SLAB_DESTROY_BY_RCU))
2150 flags |= SLAB_POISON;
2152 if (flags & SLAB_DESTROY_BY_RCU)
2153 BUG_ON(flags & SLAB_POISON);
2156 * Always checks flags, a caller might be expecting debug support which
2159 BUG_ON(flags & ~CREATE_MASK);
2162 * Check that size is in terms of words. This is needed to avoid
2163 * unaligned accesses for some archs when redzoning is used, and makes
2164 * sure any on-slab bufctl's are also correctly aligned.
2166 if (size & (BYTES_PER_WORD - 1)) {
2167 size += (BYTES_PER_WORD - 1);
2168 size &= ~(BYTES_PER_WORD - 1);
2171 /* calculate the final buffer alignment: */
2173 /* 1) arch recommendation: can be overridden for debug */
2174 if (flags & SLAB_HWCACHE_ALIGN) {
2176 * Default alignment: as specified by the arch code. Except if
2177 * an object is really small, then squeeze multiple objects into
2180 ralign = cache_line_size();
2181 while (size <= ralign / 2)
2184 ralign = BYTES_PER_WORD;
2188 * Redzoning and user store require word alignment or possibly larger.
2189 * Note this will be overridden by architecture or caller mandated
2190 * alignment if either is greater than BYTES_PER_WORD.
2192 if (flags & SLAB_STORE_USER)
2193 ralign = BYTES_PER_WORD;
2195 if (flags & SLAB_RED_ZONE) {
2196 ralign = REDZONE_ALIGN;
2197 /* If redzoning, ensure that the second redzone is suitably
2198 * aligned, by adjusting the object size accordingly. */
2199 size += REDZONE_ALIGN - 1;
2200 size &= ~(REDZONE_ALIGN - 1);
2203 /* 2) arch mandated alignment */
2204 if (ralign < ARCH_SLAB_MINALIGN) {
2205 ralign = ARCH_SLAB_MINALIGN;
2207 /* 3) caller mandated alignment */
2208 if (ralign < align) {
2211 /* disable debug if necessary */
2212 if (ralign > __alignof__(unsigned long long))
2213 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2219 if (slab_is_available())
2224 /* Get cache's description obj. */
2225 cachep = kmem_cache_zalloc(&cache_cache, gfp);
2230 cachep->obj_size = size;
2233 * Both debugging options require word-alignment which is calculated
2236 if (flags & SLAB_RED_ZONE) {
2237 /* add space for red zone words */
2238 cachep->obj_offset += sizeof(unsigned long long);
2239 size += 2 * sizeof(unsigned long long);
2241 if (flags & SLAB_STORE_USER) {
2242 /* user store requires one word storage behind the end of
2243 * the real object. But if the second red zone needs to be
2244 * aligned to 64 bits, we must allow that much space.
2246 if (flags & SLAB_RED_ZONE)
2247 size += REDZONE_ALIGN;
2249 size += BYTES_PER_WORD;
2251 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2252 if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
2253 && cachep->obj_size > cache_line_size() && size < PAGE_SIZE) {
2254 cachep->obj_offset += PAGE_SIZE - size;
2261 * Determine if the slab management is 'on' or 'off' slab.
2262 * (bootstrapping cannot cope with offslab caches so don't do
2265 if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init)
2267 * Size is large, assume best to place the slab management obj
2268 * off-slab (should allow better packing of objs).
2270 flags |= CFLGS_OFF_SLAB;
2272 size = ALIGN(size, align);
2274 left_over = calculate_slab_order(cachep, size, align, flags);
2278 "kmem_cache_create: couldn't create cache %s.\n", name);
2279 kmem_cache_free(&cache_cache, cachep);
2283 slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
2284 + sizeof(struct slab), align);
2287 * If the slab has been placed off-slab, and we have enough space then
2288 * move it on-slab. This is at the expense of any extra colouring.
2290 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
2291 flags &= ~CFLGS_OFF_SLAB;
2292 left_over -= slab_size;
2295 if (flags & CFLGS_OFF_SLAB) {
2296 /* really off slab. No need for manual alignment */
2298 cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
2301 cachep->colour_off = cache_line_size();
2302 /* Offset must be a multiple of the alignment. */
2303 if (cachep->colour_off < align)
2304 cachep->colour_off = align;
2305 cachep->colour = left_over / cachep->colour_off;
2306 cachep->slab_size = slab_size;
2307 cachep->flags = flags;
2308 cachep->gfpflags = 0;
2309 if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
2310 cachep->gfpflags |= GFP_DMA;
2311 cachep->buffer_size = size;
2312 cachep->reciprocal_buffer_size = reciprocal_value(size);
2314 if (flags & CFLGS_OFF_SLAB) {
2315 cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
2317 * This is a possibility for one of the malloc_sizes caches.
2318 * But since we go off slab only for object size greater than
2319 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2320 * this should not happen at all.
2321 * But leave a BUG_ON for some lucky dude.
2323 BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
2325 cachep->ctor = ctor;
2326 cachep->name = name;
2328 if (setup_cpu_cache(cachep, gfp)) {
2329 __kmem_cache_destroy(cachep);
2334 /* cache setup completed, link it into the list */
2335 list_add(&cachep->next, &cache_chain);
2337 if (!cachep && (flags & SLAB_PANIC))
2338 panic("kmem_cache_create(): failed to create slab `%s'\n",
2340 if (slab_is_available()) {
2341 mutex_unlock(&cache_chain_mutex);
2346 EXPORT_SYMBOL(kmem_cache_create);
2349 static void check_irq_off(void)
2351 BUG_ON(!irqs_disabled());
2354 static void check_irq_on(void)
2356 BUG_ON(irqs_disabled());
2359 static void check_spinlock_acquired(struct kmem_cache *cachep)
2363 assert_spin_locked(&cachep->nodelists[numa_node_id()]->list_lock);
2367 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2371 assert_spin_locked(&cachep->nodelists[node]->list_lock);
2376 #define check_irq_off() do { } while(0)
2377 #define check_irq_on() do { } while(0)
2378 #define check_spinlock_acquired(x) do { } while(0)
2379 #define check_spinlock_acquired_node(x, y) do { } while(0)
2382 static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
2383 struct array_cache *ac,
2384 int force, int node);
2386 static void do_drain(void *arg)
2388 struct kmem_cache *cachep = arg;
2389 struct array_cache *ac;
2390 int node = numa_node_id();
2393 ac = cpu_cache_get(cachep);
2394 spin_lock(&cachep->nodelists[node]->list_lock);
2395 free_block(cachep, ac->entry, ac->avail, node);
2396 spin_unlock(&cachep->nodelists[node]->list_lock);
2400 static void drain_cpu_caches(struct kmem_cache *cachep)
2402 struct kmem_list3 *l3;
2405 on_each_cpu(do_drain, cachep, 1);
2407 for_each_online_node(node) {
2408 l3 = cachep->nodelists[node];
2409 if (l3 && l3->alien)
2410 drain_alien_cache(cachep, l3->alien);
2413 for_each_online_node(node) {
2414 l3 = cachep->nodelists[node];
2416 drain_array(cachep, l3, l3->shared, 1, node);
2421 * Remove slabs from the list of free slabs.
2422 * Specify the number of slabs to drain in tofree.
2424 * Returns the actual number of slabs released.
2426 static int drain_freelist(struct kmem_cache *cache,
2427 struct kmem_list3 *l3, int tofree)
2429 struct list_head *p;
2434 while (nr_freed < tofree && !list_empty(&l3->slabs_free)) {
2436 spin_lock_irq(&l3->list_lock);
2437 p = l3->slabs_free.prev;
2438 if (p == &l3->slabs_free) {
2439 spin_unlock_irq(&l3->list_lock);
2443 slabp = list_entry(p, struct slab, list);
2445 BUG_ON(slabp->inuse);
2447 list_del(&slabp->list);
2449 * Safe to drop the lock. The slab is no longer linked
2452 l3->free_objects -= cache->num;
2453 spin_unlock_irq(&l3->list_lock);
2454 slab_destroy(cache, slabp);
2461 /* Called with cache_chain_mutex held to protect against cpu hotplug */
2462 static int __cache_shrink(struct kmem_cache *cachep)
2465 struct kmem_list3 *l3;
2467 drain_cpu_caches(cachep);
2470 for_each_online_node(i) {
2471 l3 = cachep->nodelists[i];
2475 drain_freelist(cachep, l3, l3->free_objects);
2477 ret += !list_empty(&l3->slabs_full) ||
2478 !list_empty(&l3->slabs_partial);
2480 return (ret ? 1 : 0);
2484 * kmem_cache_shrink - Shrink a cache.
2485 * @cachep: The cache to shrink.
2487 * Releases as many slabs as possible for a cache.
2488 * To help debugging, a zero exit status indicates all slabs were released.
2490 int kmem_cache_shrink(struct kmem_cache *cachep)
2493 BUG_ON(!cachep || in_interrupt());
2496 mutex_lock(&cache_chain_mutex);
2497 ret = __cache_shrink(cachep);
2498 mutex_unlock(&cache_chain_mutex);
2502 EXPORT_SYMBOL(kmem_cache_shrink);
2505 * kmem_cache_destroy - delete a cache
2506 * @cachep: the cache to destroy
2508 * Remove a &struct kmem_cache object from the slab cache.
2510 * It is expected this function will be called by a module when it is
2511 * unloaded. This will remove the cache completely, and avoid a duplicate
2512 * cache being allocated each time a module is loaded and unloaded, if the
2513 * module doesn't have persistent in-kernel storage across loads and unloads.
2515 * The cache must be empty before calling this function.
2517 * The caller must guarantee that noone will allocate memory from the cache
2518 * during the kmem_cache_destroy().
2520 void kmem_cache_destroy(struct kmem_cache *cachep)
2522 BUG_ON(!cachep || in_interrupt());
2524 /* Find the cache in the chain of caches. */
2526 mutex_lock(&cache_chain_mutex);
2528 * the chain is never empty, cache_cache is never destroyed
2530 list_del(&cachep->next);
2531 if (__cache_shrink(cachep)) {
2532 slab_error(cachep, "Can't free all objects");
2533 list_add(&cachep->next, &cache_chain);
2534 mutex_unlock(&cache_chain_mutex);
2539 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
2542 __kmem_cache_destroy(cachep);
2543 mutex_unlock(&cache_chain_mutex);
2546 EXPORT_SYMBOL(kmem_cache_destroy);
2549 * Get the memory for a slab management obj.
2550 * For a slab cache when the slab descriptor is off-slab, slab descriptors
2551 * always come from malloc_sizes caches. The slab descriptor cannot
2552 * come from the same cache which is getting created because,
2553 * when we are searching for an appropriate cache for these
2554 * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2555 * If we are creating a malloc_sizes cache here it would not be visible to
2556 * kmem_find_general_cachep till the initialization is complete.
2557 * Hence we cannot have slabp_cache same as the original cache.
2559 static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,
2560 int colour_off, gfp_t local_flags,
2565 if (OFF_SLAB(cachep)) {
2566 /* Slab management obj is off-slab. */
2567 slabp = kmem_cache_alloc_node(cachep->slabp_cache,
2568 local_flags, nodeid);
2570 * If the first object in the slab is leaked (it's allocated
2571 * but no one has a reference to it), we want to make sure
2572 * kmemleak does not treat the ->s_mem pointer as a reference
2573 * to the object. Otherwise we will not report the leak.
2575 kmemleak_scan_area(slabp, offsetof(struct slab, list),
2576 sizeof(struct list_head), local_flags);
2580 slabp = objp + colour_off;
2581 colour_off += cachep->slab_size;
2584 slabp->colouroff = colour_off;
2585 slabp->s_mem = objp + colour_off;
2586 slabp->nodeid = nodeid;
2591 static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
2593 return (kmem_bufctl_t *) (slabp + 1);
2596 static void cache_init_objs(struct kmem_cache *cachep,
2601 for (i = 0; i < cachep->num; i++) {
2602 void *objp = index_to_obj(cachep, slabp, i);
2604 /* need to poison the objs? */
2605 if (cachep->flags & SLAB_POISON)
2606 poison_obj(cachep, objp, POISON_FREE);
2607 if (cachep->flags & SLAB_STORE_USER)
2608 *dbg_userword(cachep, objp) = NULL;
2610 if (cachep->flags & SLAB_RED_ZONE) {
2611 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2612 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2615 * Constructors are not allowed to allocate memory from the same
2616 * cache which they are a constructor for. Otherwise, deadlock.
2617 * They must also be threaded.
2619 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2620 cachep->ctor(objp + obj_offset(cachep));
2622 if (cachep->flags & SLAB_RED_ZONE) {
2623 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2624 slab_error(cachep, "constructor overwrote the"
2625 " end of an object");
2626 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2627 slab_error(cachep, "constructor overwrote the"
2628 " start of an object");
2630 if ((cachep->buffer_size % PAGE_SIZE) == 0 &&
2631 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2632 kernel_map_pages(virt_to_page(objp),
2633 cachep->buffer_size / PAGE_SIZE, 0);
2638 slab_bufctl(slabp)[i] = i + 1;
2640 slab_bufctl(slabp)[i - 1] = BUFCTL_END;
2643 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2645 if (CONFIG_ZONE_DMA_FLAG) {
2646 if (flags & GFP_DMA)
2647 BUG_ON(!(cachep->gfpflags & GFP_DMA));
2649 BUG_ON(cachep->gfpflags & GFP_DMA);
2653 static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
2656 void *objp = index_to_obj(cachep, slabp, slabp->free);
2660 next = slab_bufctl(slabp)[slabp->free];
2662 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2663 WARN_ON(slabp->nodeid != nodeid);
2670 static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
2671 void *objp, int nodeid)
2673 unsigned int objnr = obj_to_index(cachep, slabp, objp);
2676 /* Verify that the slab belongs to the intended node */
2677 WARN_ON(slabp->nodeid != nodeid);
2679 if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
2680 printk(KERN_ERR "slab: double free detected in cache "
2681 "'%s', objp %p\n", cachep->name, objp);
2685 slab_bufctl(slabp)[objnr] = slabp->free;
2686 slabp->free = objnr;
2691 * Map pages beginning at addr to the given cache and slab. This is required
2692 * for the slab allocator to be able to lookup the cache and slab of a
2693 * virtual address for kfree, ksize, kmem_ptr_validate, and slab debugging.
2695 static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
2701 page = virt_to_page(addr);
2704 if (likely(!PageCompound(page)))
2705 nr_pages <<= cache->gfporder;
2708 page_set_cache(page, cache);
2709 page_set_slab(page, slab);
2711 } while (--nr_pages);
2715 * Grow (by 1) the number of slabs within a cache. This is called by
2716 * kmem_cache_alloc() when there are no active objs left in a cache.
2718 static int cache_grow(struct kmem_cache *cachep,
2719 gfp_t flags, int nodeid, void *objp)
2724 struct kmem_list3 *l3;
2727 * Be lazy and only check for valid flags here, keeping it out of the
2728 * critical path in kmem_cache_alloc().
2730 BUG_ON(flags & GFP_SLAB_BUG_MASK);
2731 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2733 /* Take the l3 list lock to change the colour_next on this node */
2735 l3 = cachep->nodelists[nodeid];
2736 spin_lock(&l3->list_lock);
2738 /* Get colour for the slab, and cal the next value. */
2739 offset = l3->colour_next;
2741 if (l3->colour_next >= cachep->colour)
2742 l3->colour_next = 0;
2743 spin_unlock(&l3->list_lock);
2745 offset *= cachep->colour_off;
2747 if (local_flags & __GFP_WAIT)
2751 * The test for missing atomic flag is performed here, rather than
2752 * the more obvious place, simply to reduce the critical path length
2753 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2754 * will eventually be caught here (where it matters).
2756 kmem_flagcheck(cachep, flags);
2759 * Get mem for the objs. Attempt to allocate a physical page from
2763 objp = kmem_getpages(cachep, local_flags, nodeid);
2767 /* Get slab management. */
2768 slabp = alloc_slabmgmt(cachep, objp, offset,
2769 local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
2773 slab_map_pages(cachep, slabp, objp);
2775 cache_init_objs(cachep, slabp);
2777 if (local_flags & __GFP_WAIT)
2778 local_irq_disable();
2780 spin_lock(&l3->list_lock);
2782 /* Make slab active. */
2783 list_add_tail(&slabp->list, &(l3->slabs_free));
2784 STATS_INC_GROWN(cachep);
2785 l3->free_objects += cachep->num;
2786 spin_unlock(&l3->list_lock);
2789 kmem_freepages(cachep, objp);
2791 if (local_flags & __GFP_WAIT)
2792 local_irq_disable();
2799 * Perform extra freeing checks:
2800 * - detect bad pointers.
2801 * - POISON/RED_ZONE checking
2803 static void kfree_debugcheck(const void *objp)
2805 if (!virt_addr_valid(objp)) {
2806 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2807 (unsigned long)objp);
2812 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2814 unsigned long long redzone1, redzone2;
2816 redzone1 = *dbg_redzone1(cache, obj);
2817 redzone2 = *dbg_redzone2(cache, obj);
2822 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2825 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2826 slab_error(cache, "double free detected");
2828 slab_error(cache, "memory outside object was overwritten");
2830 printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
2831 obj, redzone1, redzone2);
2834 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2841 BUG_ON(virt_to_cache(objp) != cachep);
2843 objp -= obj_offset(cachep);
2844 kfree_debugcheck(objp);
2845 page = virt_to_head_page(objp);
2847 slabp = page_get_slab(page);
2849 if (cachep->flags & SLAB_RED_ZONE) {
2850 verify_redzone_free(cachep, objp);
2851 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2852 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2854 if (cachep->flags & SLAB_STORE_USER)
2855 *dbg_userword(cachep, objp) = caller;
2857 objnr = obj_to_index(cachep, slabp, objp);
2859 BUG_ON(objnr >= cachep->num);
2860 BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
2862 #ifdef CONFIG_DEBUG_SLAB_LEAK
2863 slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
2865 if (cachep->flags & SLAB_POISON) {
2866 #ifdef CONFIG_DEBUG_PAGEALLOC
2867 if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2868 store_stackinfo(cachep, objp, (unsigned long)caller);
2869 kernel_map_pages(virt_to_page(objp),
2870 cachep->buffer_size / PAGE_SIZE, 0);
2872 poison_obj(cachep, objp, POISON_FREE);
2875 poison_obj(cachep, objp, POISON_FREE);
2881 static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
2886 /* Check slab's freelist to see if this obj is there. */
2887 for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
2889 if (entries > cachep->num || i >= cachep->num)
2892 if (entries != cachep->num - slabp->inuse) {
2894 printk(KERN_ERR "slab: Internal list corruption detected in "
2895 "cache '%s'(%d), slabp %p(%d). Hexdump:\n",
2896 cachep->name, cachep->num, slabp, slabp->inuse);
2898 i < sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t);
2901 printk("\n%03x:", i);
2902 printk(" %02x", ((unsigned char *)slabp)[i]);
2909 #define kfree_debugcheck(x) do { } while(0)
2910 #define cache_free_debugcheck(x,objp,z) (objp)
2911 #define check_slabp(x,y) do { } while(0)
2914 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
2917 struct kmem_list3 *l3;
2918 struct array_cache *ac;
2923 node = numa_node_id();
2924 ac = cpu_cache_get(cachep);
2925 batchcount = ac->batchcount;
2926 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2928 * If there was little recent activity on this cache, then
2929 * perform only a partial refill. Otherwise we could generate
2932 batchcount = BATCHREFILL_LIMIT;
2934 l3 = cachep->nodelists[node];
2936 BUG_ON(ac->avail > 0 || !l3);
2937 spin_lock(&l3->list_lock);
2939 /* See if we can refill from the shared array */
2940 if (l3->shared && transfer_objects(ac, l3->shared, batchcount))
2943 while (batchcount > 0) {
2944 struct list_head *entry;
2946 /* Get slab alloc is to come from. */
2947 entry = l3->slabs_partial.next;
2948 if (entry == &l3->slabs_partial) {
2949 l3->free_touched = 1;
2950 entry = l3->slabs_free.next;
2951 if (entry == &l3->slabs_free)
2955 slabp = list_entry(entry, struct slab, list);
2956 check_slabp(cachep, slabp);
2957 check_spinlock_acquired(cachep);
2960 * The slab was either on partial or free list so
2961 * there must be at least one object available for
2964 BUG_ON(slabp->inuse >= cachep->num);
2966 while (slabp->inuse < cachep->num && batchcount--) {
2967 STATS_INC_ALLOCED(cachep);
2968 STATS_INC_ACTIVE(cachep);
2969 STATS_SET_HIGH(cachep);
2971 ac->entry[ac->avail++] = slab_get_obj(cachep, slabp,
2974 check_slabp(cachep, slabp);
2976 /* move slabp to correct slabp list: */
2977 list_del(&slabp->list);
2978 if (slabp->free == BUFCTL_END)
2979 list_add(&slabp->list, &l3->slabs_full);
2981 list_add(&slabp->list, &l3->slabs_partial);
2985 l3->free_objects -= ac->avail;
2987 spin_unlock(&l3->list_lock);
2989 if (unlikely(!ac->avail)) {
2991 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
2993 /* cache_grow can reenable interrupts, then ac could change. */
2994 ac = cpu_cache_get(cachep);
2995 if (!x && ac->avail == 0) /* no objects in sight? abort */
2998 if (!ac->avail) /* objects refilled by interrupt? */
3002 return ac->entry[--ac->avail];
3005 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
3008 might_sleep_if(flags & __GFP_WAIT);
3010 kmem_flagcheck(cachep, flags);
3015 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
3016 gfp_t flags, void *objp, void *caller)
3020 if (cachep->flags & SLAB_POISON) {
3021 #ifdef CONFIG_DEBUG_PAGEALLOC
3022 if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
3023 kernel_map_pages(virt_to_page(objp),
3024 cachep->buffer_size / PAGE_SIZE, 1);
3026 check_poison_obj(cachep, objp);
3028 check_poison_obj(cachep, objp);
3030 poison_obj(cachep, objp, POISON_INUSE);
3032 if (cachep->flags & SLAB_STORE_USER)
3033 *dbg_userword(cachep, objp) = caller;
3035 if (cachep->flags & SLAB_RED_ZONE) {
3036 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
3037 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
3038 slab_error(cachep, "double free, or memory outside"
3039 " object was overwritten");
3041 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3042 objp, *dbg_redzone1(cachep, objp),
3043 *dbg_redzone2(cachep, objp));
3045 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
3046 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
3048 #ifdef CONFIG_DEBUG_SLAB_LEAK
3053 slabp = page_get_slab(virt_to_head_page(objp));
3054 objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;
3055 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
3058 objp += obj_offset(cachep);
3059 if (cachep->ctor && cachep->flags & SLAB_POISON)
3061 #if ARCH_SLAB_MINALIGN
3062 if ((u32)objp & (ARCH_SLAB_MINALIGN-1)) {
3063 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3064 objp, ARCH_SLAB_MINALIGN);
3070 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3073 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
3075 if (cachep == &cache_cache)
3078 return should_failslab(obj_size(cachep), flags);
3081 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3084 struct array_cache *ac;
3088 ac = cpu_cache_get(cachep);
3089 if (likely(ac->avail)) {
3090 STATS_INC_ALLOCHIT(cachep);
3092 objp = ac->entry[--ac->avail];
3094 STATS_INC_ALLOCMISS(cachep);
3095 objp = cache_alloc_refill(cachep, flags);
3098 * To avoid a false negative, if an object that is in one of the
3099 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3100 * treat the array pointers as a reference to the object.
3102 kmemleak_erase(&ac->entry[ac->avail]);
3108 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3110 * If we are in_interrupt, then process context, including cpusets and
3111 * mempolicy, may not apply and should not be used for allocation policy.
3113 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3115 int nid_alloc, nid_here;
3117 if (in_interrupt() || (flags & __GFP_THISNODE))
3119 nid_alloc = nid_here = numa_node_id();
3120 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3121 nid_alloc = cpuset_mem_spread_node();
3122 else if (current->mempolicy)
3123 nid_alloc = slab_node(current->mempolicy);
3124 if (nid_alloc != nid_here)
3125 return ____cache_alloc_node(cachep, flags, nid_alloc);
3130 * Fallback function if there was no memory available and no objects on a
3131 * certain node and fall back is permitted. First we scan all the
3132 * available nodelists for available objects. If that fails then we
3133 * perform an allocation without specifying a node. This allows the page
3134 * allocator to do its reclaim / fallback magic. We then insert the
3135 * slab into the proper nodelist and then allocate from it.
3137 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3139 struct zonelist *zonelist;
3143 enum zone_type high_zoneidx = gfp_zone(flags);
3147 if (flags & __GFP_THISNODE)
3150 zonelist = node_zonelist(slab_node(current->mempolicy), flags);
3151 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
3155 * Look through allowed nodes for objects available
3156 * from existing per node queues.
3158 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3159 nid = zone_to_nid(zone);
3161 if (cpuset_zone_allowed_hardwall(zone, flags) &&
3162 cache->nodelists[nid] &&
3163 cache->nodelists[nid]->free_objects) {
3164 obj = ____cache_alloc_node(cache,
3165 flags | GFP_THISNODE, nid);
3173 * This allocation will be performed within the constraints
3174 * of the current cpuset / memory policy requirements.
3175 * We may trigger various forms of reclaim on the allowed
3176 * set and go into memory reserves if necessary.
3178 if (local_flags & __GFP_WAIT)
3180 kmem_flagcheck(cache, flags);
3181 obj = kmem_getpages(cache, local_flags, -1);
3182 if (local_flags & __GFP_WAIT)
3183 local_irq_disable();
3186 * Insert into the appropriate per node queues
3188 nid = page_to_nid(virt_to_page(obj));
3189 if (cache_grow(cache, flags, nid, obj)) {
3190 obj = ____cache_alloc_node(cache,
3191 flags | GFP_THISNODE, nid);
3194 * Another processor may allocate the
3195 * objects in the slab since we are
3196 * not holding any locks.
3200 /* cache_grow already freed obj */
3209 * A interface to enable slab creation on nodeid
3211 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3214 struct list_head *entry;
3216 struct kmem_list3 *l3;
3220 l3 = cachep->nodelists[nodeid];
3225 spin_lock(&l3->list_lock);
3226 entry = l3->slabs_partial.next;
3227 if (entry == &l3->slabs_partial) {
3228 l3->free_touched = 1;
3229 entry = l3->slabs_free.next;
3230 if (entry == &l3->slabs_free)
3234 slabp = list_entry(entry, struct slab, list);
3235 check_spinlock_acquired_node(cachep, nodeid);
3236 check_slabp(cachep, slabp);
3238 STATS_INC_NODEALLOCS(cachep);
3239 STATS_INC_ACTIVE(cachep);
3240 STATS_SET_HIGH(cachep);
3242 BUG_ON(slabp->inuse == cachep->num);
3244 obj = slab_get_obj(cachep, slabp, nodeid);
3245 check_slabp(cachep, slabp);
3247 /* move slabp to correct slabp list: */
3248 list_del(&slabp->list);
3250 if (slabp->free == BUFCTL_END)
3251 list_add(&slabp->list, &l3->slabs_full);
3253 list_add(&slabp->list, &l3->slabs_partial);
3255 spin_unlock(&l3->list_lock);
3259 spin_unlock(&l3->list_lock);
3260 x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
3264 return fallback_alloc(cachep, flags);
3271 * kmem_cache_alloc_node - Allocate an object on the specified node
3272 * @cachep: The cache to allocate from.
3273 * @flags: See kmalloc().
3274 * @nodeid: node number of the target node.
3275 * @caller: return address of caller, used for debug information
3277 * Identical to kmem_cache_alloc but it will allocate memory on the given
3278 * node, which can improve the performance for cpu bound structures.
3280 * Fallback to other node is possible if __GFP_THISNODE is not set.
3282 static __always_inline void *
3283 __cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3286 unsigned long save_flags;
3289 lockdep_trace_alloc(flags);
3291 if (slab_should_failslab(cachep, flags))
3294 cache_alloc_debugcheck_before(cachep, flags);
3295 local_irq_save(save_flags);
3297 if (unlikely(nodeid == -1))
3298 nodeid = numa_node_id();
3300 if (unlikely(!cachep->nodelists[nodeid])) {
3301 /* Node not bootstrapped yet */
3302 ptr = fallback_alloc(cachep, flags);
3306 if (nodeid == numa_node_id()) {
3308 * Use the locally cached objects if possible.
3309 * However ____cache_alloc does not allow fallback
3310 * to other nodes. It may fail while we still have
3311 * objects on other nodes available.
3313 ptr = ____cache_alloc(cachep, flags);
3317 /* ___cache_alloc_node can fall back to other nodes */
3318 ptr = ____cache_alloc_node(cachep, flags, nodeid);
3320 local_irq_restore(save_flags);
3321 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3322 kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags,
3326 kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep));
3328 if (unlikely((flags & __GFP_ZERO) && ptr))
3329 memset(ptr, 0, obj_size(cachep));
3334 static __always_inline void *
3335 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3339 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
3340 objp = alternate_node_alloc(cache, flags);
3344 objp = ____cache_alloc(cache, flags);
3347 * We may just have run out of memory on the local node.
3348 * ____cache_alloc_node() knows how to locate memory on other nodes
3351 objp = ____cache_alloc_node(cache, flags, numa_node_id());
3358 static __always_inline void *
3359 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3361 return ____cache_alloc(cachep, flags);
3364 #endif /* CONFIG_NUMA */
3366 static __always_inline void *
3367 __cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller)
3369 unsigned long save_flags;
3372 lockdep_trace_alloc(flags);
3374 if (slab_should_failslab(cachep, flags))
3377 cache_alloc_debugcheck_before(cachep, flags);
3378 local_irq_save(save_flags);
3379 objp = __do_cache_alloc(cachep, flags);
3380 local_irq_restore(save_flags);
3381 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3382 kmemleak_alloc_recursive(objp, obj_size(cachep), 1, cachep->flags,
3387 kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep));
3389 if (unlikely((flags & __GFP_ZERO) && objp))
3390 memset(objp, 0, obj_size(cachep));
3396 * Caller needs to acquire correct kmem_list's list_lock
3398 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
3402 struct kmem_list3 *l3;
3404 for (i = 0; i < nr_objects; i++) {
3405 void *objp = objpp[i];
3408 slabp = virt_to_slab(objp);
3409 l3 = cachep->nodelists[node];
3410 list_del(&slabp->list);
3411 check_spinlock_acquired_node(cachep, node);
3412 check_slabp(cachep, slabp);
3413 slab_put_obj(cachep, slabp, objp, node);
3414 STATS_DEC_ACTIVE(cachep);
3416 check_slabp(cachep, slabp);
3418 /* fixup slab chains */
3419 if (slabp->inuse == 0) {
3420 if (l3->free_objects > l3->free_limit) {
3421 l3->free_objects -= cachep->num;
3422 /* No need to drop any previously held
3423 * lock here, even if we have a off-slab slab
3424 * descriptor it is guaranteed to come from
3425 * a different cache, refer to comments before
3428 slab_destroy(cachep, slabp);
3430 list_add(&slabp->list, &l3->slabs_free);
3433 /* Unconditionally move a slab to the end of the
3434 * partial list on free - maximum time for the
3435 * other objects to be freed, too.
3437 list_add_tail(&slabp->list, &l3->slabs_partial);
3442 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3445 struct kmem_list3 *l3;
3446 int node = numa_node_id();
3448 batchcount = ac->batchcount;
3450 BUG_ON(!batchcount || batchcount > ac->avail);
3453 l3 = cachep->nodelists[node];
3454 spin_lock(&l3->list_lock);
3456 struct array_cache *shared_array = l3->shared;
3457 int max = shared_array->limit - shared_array->avail;
3459 if (batchcount > max)
3461 memcpy(&(shared_array->entry[shared_array->avail]),
3462 ac->entry, sizeof(void *) * batchcount);
3463 shared_array->avail += batchcount;
3468 free_block(cachep, ac->entry, batchcount, node);
3473 struct list_head *p;
3475 p = l3->slabs_free.next;
3476 while (p != &(l3->slabs_free)) {
3479 slabp = list_entry(p, struct slab, list);
3480 BUG_ON(slabp->inuse);
3485 STATS_SET_FREEABLE(cachep, i);
3488 spin_unlock(&l3->list_lock);
3489 ac->avail -= batchcount;
3490 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3494 * Release an obj back to its cache. If the obj has a constructed state, it must
3495 * be in this state _before_ it is released. Called with disabled ints.
3497 static inline void __cache_free(struct kmem_cache *cachep, void *objp)
3499 struct array_cache *ac = cpu_cache_get(cachep);
3502 kmemleak_free_recursive(objp, cachep->flags);
3503 objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
3505 kmemcheck_slab_free(cachep, objp, obj_size(cachep));
3508 * Skip calling cache_free_alien() when the platform is not numa.
3509 * This will avoid cache misses that happen while accessing slabp (which
3510 * is per page memory reference) to get nodeid. Instead use a global
3511 * variable to skip the call, which is mostly likely to be present in
3514 if (numa_platform && cache_free_alien(cachep, objp))
3517 if (likely(ac->avail < ac->limit)) {
3518 STATS_INC_FREEHIT(cachep);
3519 ac->entry[ac->avail++] = objp;
3522 STATS_INC_FREEMISS(cachep);
3523 cache_flusharray(cachep, ac);
3524 ac->entry[ac->avail++] = objp;
3529 * kmem_cache_alloc - Allocate an object
3530 * @cachep: The cache to allocate from.
3531 * @flags: See kmalloc().
3533 * Allocate an object from this cache. The flags are only relevant
3534 * if the cache has no available objects.
3536 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3538 void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
3540 trace_kmem_cache_alloc(_RET_IP_, ret,
3541 obj_size(cachep), cachep->buffer_size, flags);
3545 EXPORT_SYMBOL(kmem_cache_alloc);
3547 #ifdef CONFIG_KMEMTRACE
3548 void *kmem_cache_alloc_notrace(struct kmem_cache *cachep, gfp_t flags)
3550 return __cache_alloc(cachep, flags, __builtin_return_address(0));
3552 EXPORT_SYMBOL(kmem_cache_alloc_notrace);
3556 * kmem_ptr_validate - check if an untrusted pointer might be a slab entry.
3557 * @cachep: the cache we're checking against
3558 * @ptr: pointer to validate
3560 * This verifies that the untrusted pointer looks sane;
3561 * it is _not_ a guarantee that the pointer is actually
3562 * part of the slab cache in question, but it at least
3563 * validates that the pointer can be dereferenced and
3564 * looks half-way sane.
3566 * Currently only used for dentry validation.
3568 int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr)
3570 unsigned long addr = (unsigned long)ptr;
3571 unsigned long min_addr = PAGE_OFFSET;
3572 unsigned long align_mask = BYTES_PER_WORD - 1;
3573 unsigned long size = cachep->buffer_size;
3576 if (unlikely(addr < min_addr))
3578 if (unlikely(addr > (unsigned long)high_memory - size))
3580 if (unlikely(addr & align_mask))
3582 if (unlikely(!kern_addr_valid(addr)))
3584 if (unlikely(!kern_addr_valid(addr + size - 1)))
3586 page = virt_to_page(ptr);
3587 if (unlikely(!PageSlab(page)))
3589 if (unlikely(page_get_cache(page) != cachep))
3597 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3599 void *ret = __cache_alloc_node(cachep, flags, nodeid,
3600 __builtin_return_address(0));
3602 trace_kmem_cache_alloc_node(_RET_IP_, ret,
3603 obj_size(cachep), cachep->buffer_size,
3608 EXPORT_SYMBOL(kmem_cache_alloc_node);
3610 #ifdef CONFIG_KMEMTRACE
3611 void *kmem_cache_alloc_node_notrace(struct kmem_cache *cachep,
3615 return __cache_alloc_node(cachep, flags, nodeid,
3616 __builtin_return_address(0));
3618 EXPORT_SYMBOL(kmem_cache_alloc_node_notrace);
3621 static __always_inline void *
3622 __do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller)
3624 struct kmem_cache *cachep;
3627 cachep = kmem_find_general_cachep(size, flags);
3628 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3630 ret = kmem_cache_alloc_node_notrace(cachep, flags, node);
3632 trace_kmalloc_node((unsigned long) caller, ret,
3633 size, cachep->buffer_size, flags, node);
3638 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_KMEMTRACE)
3639 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3641 return __do_kmalloc_node(size, flags, node,
3642 __builtin_return_address(0));
3644 EXPORT_SYMBOL(__kmalloc_node);
3646 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3647 int node, unsigned long caller)
3649 return __do_kmalloc_node(size, flags, node, (void *)caller);
3651 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3653 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3655 return __do_kmalloc_node(size, flags, node, NULL);
3657 EXPORT_SYMBOL(__kmalloc_node);
3658 #endif /* CONFIG_DEBUG_SLAB */
3659 #endif /* CONFIG_NUMA */
3662 * __do_kmalloc - allocate memory
3663 * @size: how many bytes of memory are required.
3664 * @flags: the type of memory to allocate (see kmalloc).
3665 * @caller: function caller for debug tracking of the caller
3667 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3670 struct kmem_cache *cachep;
3673 /* If you want to save a few bytes .text space: replace
3675 * Then kmalloc uses the uninlined functions instead of the inline
3678 cachep = __find_general_cachep(size, flags);
3679 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3681 ret = __cache_alloc(cachep, flags, caller);
3683 trace_kmalloc((unsigned long) caller, ret,
3684 size, cachep->buffer_size, flags);
3690 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_KMEMTRACE)
3691 void *__kmalloc(size_t size, gfp_t flags)
3693 return __do_kmalloc(size, flags, __builtin_return_address(0));
3695 EXPORT_SYMBOL(__kmalloc);
3697 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3699 return __do_kmalloc(size, flags, (void *)caller);
3701 EXPORT_SYMBOL(__kmalloc_track_caller);
3704 void *__kmalloc(size_t size, gfp_t flags)
3706 return __do_kmalloc(size, flags, NULL);
3708 EXPORT_SYMBOL(__kmalloc);
3712 * kmem_cache_free - Deallocate an object
3713 * @cachep: The cache the allocation was from.
3714 * @objp: The previously allocated object.
3716 * Free an object which was previously allocated from this
3719 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3721 unsigned long flags;
3723 local_irq_save(flags);
3724 debug_check_no_locks_freed(objp, obj_size(cachep));
3725 if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3726 debug_check_no_obj_freed(objp, obj_size(cachep));
3727 __cache_free(cachep, objp);
3728 local_irq_restore(flags);
3730 trace_kmem_cache_free(_RET_IP_, objp);
3732 EXPORT_SYMBOL(kmem_cache_free);
3735 * kfree - free previously allocated memory
3736 * @objp: pointer returned by kmalloc.
3738 * If @objp is NULL, no operation is performed.
3740 * Don't free memory not originally allocated by kmalloc()
3741 * or you will run into trouble.
3743 void kfree(const void *objp)
3745 struct kmem_cache *c;
3746 unsigned long flags;
3748 trace_kfree(_RET_IP_, objp);
3750 if (unlikely(ZERO_OR_NULL_PTR(objp)))
3752 local_irq_save(flags);
3753 kfree_debugcheck(objp);
3754 c = virt_to_cache(objp);
3755 debug_check_no_locks_freed(objp, obj_size(c));
3756 debug_check_no_obj_freed(objp, obj_size(c));
3757 __cache_free(c, (void *)objp);
3758 local_irq_restore(flags);
3760 EXPORT_SYMBOL(kfree);
3762 unsigned int kmem_cache_size(struct kmem_cache *cachep)
3764 return obj_size(cachep);
3766 EXPORT_SYMBOL(kmem_cache_size);
3768 const char *kmem_cache_name(struct kmem_cache *cachep)
3770 return cachep->name;
3772 EXPORT_SYMBOL_GPL(kmem_cache_name);
3775 * This initializes kmem_list3 or resizes various caches for all nodes.
3777 static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
3780 struct kmem_list3 *l3;
3781 struct array_cache *new_shared;
3782 struct array_cache **new_alien = NULL;
3784 for_each_online_node(node) {
3786 if (use_alien_caches) {
3787 new_alien = alloc_alien_cache(node, cachep->limit, gfp);
3793 if (cachep->shared) {
3794 new_shared = alloc_arraycache(node,
3795 cachep->shared*cachep->batchcount,
3798 free_alien_cache(new_alien);
3803 l3 = cachep->nodelists[node];
3805 struct array_cache *shared = l3->shared;
3807 spin_lock_irq(&l3->list_lock);
3810 free_block(cachep, shared->entry,
3811 shared->avail, node);
3813 l3->shared = new_shared;
3815 l3->alien = new_alien;
3818 l3->free_limit = (1 + nr_cpus_node(node)) *
3819 cachep->batchcount + cachep->num;
3820 spin_unlock_irq(&l3->list_lock);
3822 free_alien_cache(new_alien);
3825 l3 = kmalloc_node(sizeof(struct kmem_list3), gfp, node);
3827 free_alien_cache(new_alien);
3832 kmem_list3_init(l3);
3833 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
3834 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
3835 l3->shared = new_shared;
3836 l3->alien = new_alien;
3837 l3->free_limit = (1 + nr_cpus_node(node)) *
3838 cachep->batchcount + cachep->num;
3839 cachep->nodelists[node] = l3;
3844 if (!cachep->next.next) {
3845 /* Cache is not active yet. Roll back what we did */
3848 if (cachep->nodelists[node]) {
3849 l3 = cachep->nodelists[node];
3852 free_alien_cache(l3->alien);
3854 cachep->nodelists[node] = NULL;
3862 struct ccupdate_struct {
3863 struct kmem_cache *cachep;
3864 struct array_cache *new[NR_CPUS];
3867 static void do_ccupdate_local(void *info)
3869 struct ccupdate_struct *new = info;
3870 struct array_cache *old;
3873 old = cpu_cache_get(new->cachep);
3875 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
3876 new->new[smp_processor_id()] = old;
3879 /* Always called with the cache_chain_mutex held */
3880 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3881 int batchcount, int shared, gfp_t gfp)
3883 struct ccupdate_struct *new;
3886 new = kzalloc(sizeof(*new), gfp);
3890 for_each_online_cpu(i) {
3891 new->new[i] = alloc_arraycache(cpu_to_node(i), limit,
3894 for (i--; i >= 0; i--)
3900 new->cachep = cachep;
3902 on_each_cpu(do_ccupdate_local, (void *)new, 1);
3905 cachep->batchcount = batchcount;
3906 cachep->limit = limit;
3907 cachep->shared = shared;
3909 for_each_online_cpu(i) {
3910 struct array_cache *ccold = new->new[i];
3913 spin_lock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3914 free_block(cachep, ccold->entry, ccold->avail, cpu_to_node(i));
3915 spin_unlock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3919 return alloc_kmemlist(cachep, gfp);
3922 /* Called with cache_chain_mutex held always */
3923 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3929 * The head array serves three purposes:
3930 * - create a LIFO ordering, i.e. return objects that are cache-warm
3931 * - reduce the number of spinlock operations.
3932 * - reduce the number of linked list operations on the slab and
3933 * bufctl chains: array operations are cheaper.
3934 * The numbers are guessed, we should auto-tune as described by
3937 if (cachep->buffer_size > 131072)
3939 else if (cachep->buffer_size > PAGE_SIZE)
3941 else if (cachep->buffer_size > 1024)
3943 else if (cachep->buffer_size > 256)
3949 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3950 * allocation behaviour: Most allocs on one cpu, most free operations
3951 * on another cpu. For these cases, an efficient object passing between
3952 * cpus is necessary. This is provided by a shared array. The array
3953 * replaces Bonwick's magazine layer.
3954 * On uniprocessor, it's functionally equivalent (but less efficient)
3955 * to a larger limit. Thus disabled by default.
3958 if (cachep->buffer_size <= PAGE_SIZE && num_possible_cpus() > 1)
3963 * With debugging enabled, large batchcount lead to excessively long
3964 * periods with disabled local interrupts. Limit the batchcount
3969 err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared, gfp);
3971 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
3972 cachep->name, -err);
3977 * Drain an array if it contains any elements taking the l3 lock only if
3978 * necessary. Note that the l3 listlock also protects the array_cache
3979 * if drain_array() is used on the shared array.
3981 void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
3982 struct array_cache *ac, int force, int node)
3986 if (!ac || !ac->avail)
3988 if (ac->touched && !force) {
3991 spin_lock_irq(&l3->list_lock);
3993 tofree = force ? ac->avail : (ac->limit + 4) / 5;
3994 if (tofree > ac->avail)
3995 tofree = (ac->avail + 1) / 2;
3996 free_block(cachep, ac->entry, tofree, node);
3997 ac->avail -= tofree;
3998 memmove(ac->entry, &(ac->entry[tofree]),
3999 sizeof(void *) * ac->avail);
4001 spin_unlock_irq(&l3->list_lock);
4006 * cache_reap - Reclaim memory from caches.
4007 * @w: work descriptor
4009 * Called from workqueue/eventd every few seconds.
4011 * - clear the per-cpu caches for this CPU.
4012 * - return freeable pages to the main free memory pool.
4014 * If we cannot acquire the cache chain mutex then just give up - we'll try
4015 * again on the next iteration.
4017 static void cache_reap(struct work_struct *w)
4019 struct kmem_cache *searchp;
4020 struct kmem_list3 *l3;
4021 int node = numa_node_id();
4022 struct delayed_work *work = to_delayed_work(w);
4024 if (!mutex_trylock(&cache_chain_mutex))
4025 /* Give up. Setup the next iteration. */
4028 list_for_each_entry(searchp, &cache_chain, next) {
4032 * We only take the l3 lock if absolutely necessary and we
4033 * have established with reasonable certainty that
4034 * we can do some work if the lock was obtained.
4036 l3 = searchp->nodelists[node];
4038 reap_alien(searchp, l3);
4040 drain_array(searchp, l3, cpu_cache_get(searchp), 0, node);
4043 * These are racy checks but it does not matter
4044 * if we skip one check or scan twice.
4046 if (time_after(l3->next_reap, jiffies))
4049 l3->next_reap = jiffies + REAPTIMEOUT_LIST3;
4051 drain_array(searchp, l3, l3->shared, 0, node);
4053 if (l3->free_touched)
4054 l3->free_touched = 0;
4058 freed = drain_freelist(searchp, l3, (l3->free_limit +
4059 5 * searchp->num - 1) / (5 * searchp->num));
4060 STATS_ADD_REAPED(searchp, freed);
4066 mutex_unlock(&cache_chain_mutex);
4069 /* Set up the next iteration */
4070 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
4073 #ifdef CONFIG_SLABINFO
4075 static void print_slabinfo_header(struct seq_file *m)
4078 * Output format version, so at least we can change it
4079 * without _too_ many complaints.
4082 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
4084 seq_puts(m, "slabinfo - version: 2.1\n");
4086 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
4087 "<objperslab> <pagesperslab>");
4088 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
4089 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4091 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
4092 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
4093 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
4098 static void *s_start(struct seq_file *m, loff_t *pos)
4102 mutex_lock(&cache_chain_mutex);
4104 print_slabinfo_header(m);
4106 return seq_list_start(&cache_chain, *pos);
4109 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
4111 return seq_list_next(p, &cache_chain, pos);
4114 static void s_stop(struct seq_file *m, void *p)
4116 mutex_unlock(&cache_chain_mutex);
4119 static int s_show(struct seq_file *m, void *p)
4121 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
4123 unsigned long active_objs;
4124 unsigned long num_objs;
4125 unsigned long active_slabs = 0;
4126 unsigned long num_slabs, free_objects = 0, shared_avail = 0;
4130 struct kmem_list3 *l3;
4134 for_each_online_node(node) {
4135 l3 = cachep->nodelists[node];
4140 spin_lock_irq(&l3->list_lock);
4142 list_for_each_entry(slabp, &l3->slabs_full, list) {
4143 if (slabp->inuse != cachep->num && !error)
4144 error = "slabs_full accounting error";
4145 active_objs += cachep->num;
4148 list_for_each_entry(slabp, &l3->slabs_partial, list) {
4149 if (slabp->inuse == cachep->num && !error)
4150 error = "slabs_partial inuse accounting error";
4151 if (!slabp->inuse && !error)
4152 error = "slabs_partial/inuse accounting error";
4153 active_objs += slabp->inuse;
4156 list_for_each_entry(slabp, &l3->slabs_free, list) {
4157 if (slabp->inuse && !error)
4158 error = "slabs_free/inuse accounting error";
4161 free_objects += l3->free_objects;
4163 shared_avail += l3->shared->avail;
4165 spin_unlock_irq(&l3->list_lock);
4167 num_slabs += active_slabs;
4168 num_objs = num_slabs * cachep->num;
4169 if (num_objs - active_objs != free_objects && !error)
4170 error = "free_objects accounting error";
4172 name = cachep->name;
4174 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
4176 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
4177 name, active_objs, num_objs, cachep->buffer_size,
4178 cachep->num, (1 << cachep->gfporder));
4179 seq_printf(m, " : tunables %4u %4u %4u",
4180 cachep->limit, cachep->batchcount, cachep->shared);
4181 seq_printf(m, " : slabdata %6lu %6lu %6lu",
4182 active_slabs, num_slabs, shared_avail);
4185 unsigned long high = cachep->high_mark;
4186 unsigned long allocs = cachep->num_allocations;
4187 unsigned long grown = cachep->grown;
4188 unsigned long reaped = cachep->reaped;
4189 unsigned long errors = cachep->errors;
4190 unsigned long max_freeable = cachep->max_freeable;
4191 unsigned long node_allocs = cachep->node_allocs;
4192 unsigned long node_frees = cachep->node_frees;
4193 unsigned long overflows = cachep->node_overflow;
4195 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu \
4196 %4lu %4lu %4lu %4lu %4lu", allocs, high, grown,
4197 reaped, errors, max_freeable, node_allocs,
4198 node_frees, overflows);
4202 unsigned long allochit = atomic_read(&cachep->allochit);
4203 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4204 unsigned long freehit = atomic_read(&cachep->freehit);
4205 unsigned long freemiss = atomic_read(&cachep->freemiss);
4207 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4208 allochit, allocmiss, freehit, freemiss);
4216 * slabinfo_op - iterator that generates /proc/slabinfo
4225 * num-pages-per-slab
4226 * + further values on SMP and with statistics enabled
4229 static const struct seq_operations slabinfo_op = {
4236 #define MAX_SLABINFO_WRITE 128
4238 * slabinfo_write - Tuning for the slab allocator
4240 * @buffer: user buffer
4241 * @count: data length
4244 ssize_t slabinfo_write(struct file *file, const char __user * buffer,
4245 size_t count, loff_t *ppos)
4247 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4248 int limit, batchcount, shared, res;
4249 struct kmem_cache *cachep;
4251 if (count > MAX_SLABINFO_WRITE)
4253 if (copy_from_user(&kbuf, buffer, count))
4255 kbuf[MAX_SLABINFO_WRITE] = '\0';
4257 tmp = strchr(kbuf, ' ');
4262 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4265 /* Find the cache in the chain of caches. */
4266 mutex_lock(&cache_chain_mutex);
4268 list_for_each_entry(cachep, &cache_chain, next) {
4269 if (!strcmp(cachep->name, kbuf)) {
4270 if (limit < 1 || batchcount < 1 ||
4271 batchcount > limit || shared < 0) {
4274 res = do_tune_cpucache(cachep, limit,
4281 mutex_unlock(&cache_chain_mutex);
4287 static int slabinfo_open(struct inode *inode, struct file *file)
4289 return seq_open(file, &slabinfo_op);
4292 static const struct file_operations proc_slabinfo_operations = {
4293 .open = slabinfo_open,
4295 .write = slabinfo_write,
4296 .llseek = seq_lseek,
4297 .release = seq_release,
4300 #ifdef CONFIG_DEBUG_SLAB_LEAK
4302 static void *leaks_start(struct seq_file *m, loff_t *pos)
4304 mutex_lock(&cache_chain_mutex);
4305 return seq_list_start(&cache_chain, *pos);
4308 static inline int add_caller(unsigned long *n, unsigned long v)
4318 unsigned long *q = p + 2 * i;
4332 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4338 static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
4344 for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) {
4345 if (slab_bufctl(s)[i] != BUFCTL_ACTIVE)
4347 if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4352 static void show_symbol(struct seq_file *m, unsigned long address)
4354 #ifdef CONFIG_KALLSYMS
4355 unsigned long offset, size;
4356 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4358 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4359 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4361 seq_printf(m, " [%s]", modname);
4365 seq_printf(m, "%p", (void *)address);
4368 static int leaks_show(struct seq_file *m, void *p)
4370 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
4372 struct kmem_list3 *l3;
4374 unsigned long *n = m->private;
4378 if (!(cachep->flags & SLAB_STORE_USER))
4380 if (!(cachep->flags & SLAB_RED_ZONE))
4383 /* OK, we can do it */
4387 for_each_online_node(node) {
4388 l3 = cachep->nodelists[node];
4393 spin_lock_irq(&l3->list_lock);
4395 list_for_each_entry(slabp, &l3->slabs_full, list)
4396 handle_slab(n, cachep, slabp);
4397 list_for_each_entry(slabp, &l3->slabs_partial, list)
4398 handle_slab(n, cachep, slabp);
4399 spin_unlock_irq(&l3->list_lock);
4401 name = cachep->name;
4403 /* Increase the buffer size */
4404 mutex_unlock(&cache_chain_mutex);
4405 m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4407 /* Too bad, we are really out */
4409 mutex_lock(&cache_chain_mutex);
4412 *(unsigned long *)m->private = n[0] * 2;
4414 mutex_lock(&cache_chain_mutex);
4415 /* Now make sure this entry will be retried */
4419 for (i = 0; i < n[1]; i++) {
4420 seq_printf(m, "%s: %lu ", name, n[2*i+3]);
4421 show_symbol(m, n[2*i+2]);
4428 static const struct seq_operations slabstats_op = {
4429 .start = leaks_start,
4435 static int slabstats_open(struct inode *inode, struct file *file)
4437 unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL);
4440 ret = seq_open(file, &slabstats_op);
4442 struct seq_file *m = file->private_data;
4443 *n = PAGE_SIZE / (2 * sizeof(unsigned long));
4452 static const struct file_operations proc_slabstats_operations = {
4453 .open = slabstats_open,
4455 .llseek = seq_lseek,
4456 .release = seq_release_private,
4460 static int __init slab_proc_init(void)
4462 proc_create("slabinfo",S_IWUSR|S_IRUGO,NULL,&proc_slabinfo_operations);
4463 #ifdef CONFIG_DEBUG_SLAB_LEAK
4464 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4468 module_init(slab_proc_init);
4472 * ksize - get the actual amount of memory allocated for a given object
4473 * @objp: Pointer to the object
4475 * kmalloc may internally round up allocations and return more memory
4476 * than requested. ksize() can be used to determine the actual amount of
4477 * memory allocated. The caller may use this additional memory, even though
4478 * a smaller amount of memory was initially specified with the kmalloc call.
4479 * The caller must guarantee that objp points to a valid object previously
4480 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4481 * must not be freed during the duration of the call.
4483 size_t ksize(const void *objp)
4486 if (unlikely(objp == ZERO_SIZE_PTR))
4489 return obj_size(virt_to_cache(objp));
4491 EXPORT_SYMBOL(ksize);