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/rcupdate.h>
106 #include <linux/string.h>
107 #include <linux/uaccess.h>
108 #include <linux/nodemask.h>
109 #include <linux/kmemleak.h>
110 #include <linux/mempolicy.h>
111 #include <linux/mutex.h>
112 #include <linux/fault-inject.h>
113 #include <linux/rtmutex.h>
114 #include <linux/reciprocal_div.h>
115 #include <linux/debugobjects.h>
116 #include <linux/kmemcheck.h>
117 #include <linux/memory.h>
118 #include <linux/prefetch.h>
120 #include <asm/cacheflush.h>
121 #include <asm/tlbflush.h>
122 #include <asm/page.h>
124 #include <trace/events/kmem.h>
127 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
128 * 0 for faster, smaller code (especially in the critical paths).
130 * STATS - 1 to collect stats for /proc/slabinfo.
131 * 0 for faster, smaller code (especially in the critical paths).
133 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
136 #ifdef CONFIG_DEBUG_SLAB
139 #define FORCED_DEBUG 1
143 #define FORCED_DEBUG 0
146 /* Shouldn't this be in a header file somewhere? */
147 #define BYTES_PER_WORD sizeof(void *)
148 #define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long))
150 #ifndef ARCH_KMALLOC_FLAGS
151 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
154 /* Legal flag mask for kmem_cache_create(). */
156 # define CREATE_MASK (SLAB_RED_ZONE | \
157 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
160 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
161 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
162 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
164 # define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
166 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
167 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
168 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
174 * Bufctl's are used for linking objs within a slab
177 * This implementation relies on "struct page" for locating the cache &
178 * slab an object belongs to.
179 * This allows the bufctl structure to be small (one int), but limits
180 * the number of objects a slab (not a cache) can contain when off-slab
181 * bufctls are used. The limit is the size of the largest general cache
182 * that does not use off-slab slabs.
183 * For 32bit archs with 4 kB pages, is this 56.
184 * This is not serious, as it is only for large objects, when it is unwise
185 * to have too many per slab.
186 * Note: This limit can be raised by introducing a general cache whose size
187 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
190 typedef unsigned int kmem_bufctl_t
;
191 #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
192 #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
193 #define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2)
194 #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3)
199 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
200 * arrange for kmem_freepages to be called via RCU. This is useful if
201 * we need to approach a kernel structure obliquely, from its address
202 * obtained without the usual locking. We can lock the structure to
203 * stabilize it and check it's still at the given address, only if we
204 * can be sure that the memory has not been meanwhile reused for some
205 * other kind of object (which our subsystem's lock might corrupt).
207 * rcu_read_lock before reading the address, then rcu_read_unlock after
208 * taking the spinlock within the structure expected at that address.
211 struct rcu_head head
;
212 struct kmem_cache
*cachep
;
219 * Manages the objs in a slab. Placed either at the beginning of mem allocated
220 * for a slab, or allocated from an general cache.
221 * Slabs are chained into three list: fully used, partial, fully free slabs.
226 struct list_head list
;
227 unsigned long colouroff
;
228 void *s_mem
; /* including colour offset */
229 unsigned int inuse
; /* num of objs active in slab */
231 unsigned short nodeid
;
233 struct slab_rcu __slab_cover_slab_rcu
;
241 * - LIFO ordering, to hand out cache-warm objects from _alloc
242 * - reduce the number of linked list operations
243 * - reduce spinlock operations
245 * The limit is stored in the per-cpu structure to reduce the data cache
252 unsigned int batchcount
;
253 unsigned int touched
;
256 * Must have this definition in here for the proper
257 * alignment of array_cache. Also simplifies accessing
263 * bootstrap: The caches do not work without cpuarrays anymore, but the
264 * cpuarrays are allocated from the generic caches...
266 #define BOOT_CPUCACHE_ENTRIES 1
267 struct arraycache_init
{
268 struct array_cache cache
;
269 void *entries
[BOOT_CPUCACHE_ENTRIES
];
273 * The slab lists for all objects.
276 struct list_head slabs_partial
; /* partial list first, better asm code */
277 struct list_head slabs_full
;
278 struct list_head slabs_free
;
279 unsigned long free_objects
;
280 unsigned int free_limit
;
281 unsigned int colour_next
; /* Per-node cache coloring */
282 spinlock_t list_lock
;
283 struct array_cache
*shared
; /* shared per node */
284 struct array_cache
**alien
; /* on other nodes */
285 unsigned long next_reap
; /* updated without locking */
286 int free_touched
; /* updated without locking */
290 * Need this for bootstrapping a per node allocator.
292 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
293 static struct kmem_list3 __initdata initkmem_list3
[NUM_INIT_LISTS
];
294 #define CACHE_CACHE 0
295 #define SIZE_AC MAX_NUMNODES
296 #define SIZE_L3 (2 * MAX_NUMNODES)
298 static int drain_freelist(struct kmem_cache
*cache
,
299 struct kmem_list3
*l3
, int tofree
);
300 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int len
,
302 static int enable_cpucache(struct kmem_cache
*cachep
, gfp_t gfp
);
303 static void cache_reap(struct work_struct
*unused
);
306 * This function must be completely optimized away if a constant is passed to
307 * it. Mostly the same as what is in linux/slab.h except it returns an index.
309 static __always_inline
int index_of(const size_t size
)
311 extern void __bad_size(void);
313 if (__builtin_constant_p(size
)) {
321 #include <linux/kmalloc_sizes.h>
329 static int slab_early_init
= 1;
331 #define INDEX_AC index_of(sizeof(struct arraycache_init))
332 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
334 static void kmem_list3_init(struct kmem_list3
*parent
)
336 INIT_LIST_HEAD(&parent
->slabs_full
);
337 INIT_LIST_HEAD(&parent
->slabs_partial
);
338 INIT_LIST_HEAD(&parent
->slabs_free
);
339 parent
->shared
= NULL
;
340 parent
->alien
= NULL
;
341 parent
->colour_next
= 0;
342 spin_lock_init(&parent
->list_lock
);
343 parent
->free_objects
= 0;
344 parent
->free_touched
= 0;
347 #define MAKE_LIST(cachep, listp, slab, nodeid) \
349 INIT_LIST_HEAD(listp); \
350 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
353 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
355 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
356 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
357 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
360 #define CFLGS_OFF_SLAB (0x80000000UL)
361 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
363 #define BATCHREFILL_LIMIT 16
365 * Optimization question: fewer reaps means less probability for unnessary
366 * cpucache drain/refill cycles.
368 * OTOH the cpuarrays can contain lots of objects,
369 * which could lock up otherwise freeable slabs.
371 #define REAPTIMEOUT_CPUC (2*HZ)
372 #define REAPTIMEOUT_LIST3 (4*HZ)
375 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
376 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
377 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
378 #define STATS_INC_GROWN(x) ((x)->grown++)
379 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
380 #define STATS_SET_HIGH(x) \
382 if ((x)->num_active > (x)->high_mark) \
383 (x)->high_mark = (x)->num_active; \
385 #define STATS_INC_ERR(x) ((x)->errors++)
386 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
387 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
388 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
389 #define STATS_SET_FREEABLE(x, i) \
391 if ((x)->max_freeable < i) \
392 (x)->max_freeable = i; \
394 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
395 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
396 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
397 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
399 #define STATS_INC_ACTIVE(x) do { } while (0)
400 #define STATS_DEC_ACTIVE(x) do { } while (0)
401 #define STATS_INC_ALLOCED(x) do { } while (0)
402 #define STATS_INC_GROWN(x) do { } while (0)
403 #define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0)
404 #define STATS_SET_HIGH(x) do { } while (0)
405 #define STATS_INC_ERR(x) do { } while (0)
406 #define STATS_INC_NODEALLOCS(x) do { } while (0)
407 #define STATS_INC_NODEFREES(x) do { } while (0)
408 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
409 #define STATS_SET_FREEABLE(x, i) do { } while (0)
410 #define STATS_INC_ALLOCHIT(x) do { } while (0)
411 #define STATS_INC_ALLOCMISS(x) do { } while (0)
412 #define STATS_INC_FREEHIT(x) do { } while (0)
413 #define STATS_INC_FREEMISS(x) do { } while (0)
419 * memory layout of objects:
421 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
422 * the end of an object is aligned with the end of the real
423 * allocation. Catches writes behind the end of the allocation.
424 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
426 * cachep->obj_offset: The real object.
427 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
428 * cachep->size - 1* BYTES_PER_WORD: last caller address
429 * [BYTES_PER_WORD long]
431 static int obj_offset(struct kmem_cache
*cachep
)
433 return cachep
->obj_offset
;
436 static unsigned long long *dbg_redzone1(struct kmem_cache
*cachep
, void *objp
)
438 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
439 return (unsigned long long*) (objp
+ obj_offset(cachep
) -
440 sizeof(unsigned long long));
443 static unsigned long long *dbg_redzone2(struct kmem_cache
*cachep
, void *objp
)
445 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
446 if (cachep
->flags
& SLAB_STORE_USER
)
447 return (unsigned long long *)(objp
+ cachep
->size
-
448 sizeof(unsigned long long) -
450 return (unsigned long long *) (objp
+ cachep
->size
-
451 sizeof(unsigned long long));
454 static void **dbg_userword(struct kmem_cache
*cachep
, void *objp
)
456 BUG_ON(!(cachep
->flags
& SLAB_STORE_USER
));
457 return (void **)(objp
+ cachep
->size
- BYTES_PER_WORD
);
462 #define obj_offset(x) 0
463 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
464 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
465 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
469 #ifdef CONFIG_TRACING
470 size_t slab_buffer_size(struct kmem_cache
*cachep
)
474 EXPORT_SYMBOL(slab_buffer_size
);
478 * Do not go above this order unless 0 objects fit into the slab or
479 * overridden on the command line.
481 #define SLAB_MAX_ORDER_HI 1
482 #define SLAB_MAX_ORDER_LO 0
483 static int slab_max_order
= SLAB_MAX_ORDER_LO
;
484 static bool slab_max_order_set __initdata
;
486 static inline struct kmem_cache
*page_get_cache(struct page
*page
)
488 page
= compound_head(page
);
489 BUG_ON(!PageSlab(page
));
490 return page
->slab_cache
;
493 static inline struct kmem_cache
*virt_to_cache(const void *obj
)
495 struct page
*page
= virt_to_head_page(obj
);
496 return page
->slab_cache
;
499 static inline struct slab
*virt_to_slab(const void *obj
)
501 struct page
*page
= virt_to_head_page(obj
);
503 VM_BUG_ON(!PageSlab(page
));
504 return page
->slab_page
;
507 static inline void *index_to_obj(struct kmem_cache
*cache
, struct slab
*slab
,
510 return slab
->s_mem
+ cache
->size
* idx
;
514 * We want to avoid an expensive divide : (offset / cache->size)
515 * Using the fact that size is a constant for a particular cache,
516 * we can replace (offset / cache->size) by
517 * reciprocal_divide(offset, cache->reciprocal_buffer_size)
519 static inline unsigned int obj_to_index(const struct kmem_cache
*cache
,
520 const struct slab
*slab
, void *obj
)
522 u32 offset
= (obj
- slab
->s_mem
);
523 return reciprocal_divide(offset
, cache
->reciprocal_buffer_size
);
527 * These are the default caches for kmalloc. Custom caches can have other sizes.
529 struct cache_sizes malloc_sizes
[] = {
530 #define CACHE(x) { .cs_size = (x) },
531 #include <linux/kmalloc_sizes.h>
535 EXPORT_SYMBOL(malloc_sizes
);
537 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
543 static struct cache_names __initdata cache_names
[] = {
544 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
545 #include <linux/kmalloc_sizes.h>
550 static struct arraycache_init initarray_cache __initdata
=
551 { {0, BOOT_CPUCACHE_ENTRIES
, 1, 0} };
552 static struct arraycache_init initarray_generic
=
553 { {0, BOOT_CPUCACHE_ENTRIES
, 1, 0} };
555 /* internal cache of cache description objs */
556 static struct kmem_list3
*cache_cache_nodelists
[MAX_NUMNODES
];
557 static struct kmem_cache cache_cache
= {
558 .nodelists
= cache_cache_nodelists
,
560 .limit
= BOOT_CPUCACHE_ENTRIES
,
562 .size
= sizeof(struct kmem_cache
),
563 .name
= "kmem_cache",
566 #define BAD_ALIEN_MAGIC 0x01020304ul
569 * chicken and egg problem: delay the per-cpu array allocation
570 * until the general caches are up.
582 * used by boot code to determine if it can use slab based allocator
584 int slab_is_available(void)
586 return g_cpucache_up
>= EARLY
;
589 #ifdef CONFIG_LOCKDEP
592 * Slab sometimes uses the kmalloc slabs to store the slab headers
593 * for other slabs "off slab".
594 * The locking for this is tricky in that it nests within the locks
595 * of all other slabs in a few places; to deal with this special
596 * locking we put on-slab caches into a separate lock-class.
598 * We set lock class for alien array caches which are up during init.
599 * The lock annotation will be lost if all cpus of a node goes down and
600 * then comes back up during hotplug
602 static struct lock_class_key on_slab_l3_key
;
603 static struct lock_class_key on_slab_alc_key
;
605 static struct lock_class_key debugobj_l3_key
;
606 static struct lock_class_key debugobj_alc_key
;
608 static void slab_set_lock_classes(struct kmem_cache
*cachep
,
609 struct lock_class_key
*l3_key
, struct lock_class_key
*alc_key
,
612 struct array_cache
**alc
;
613 struct kmem_list3
*l3
;
616 l3
= cachep
->nodelists
[q
];
620 lockdep_set_class(&l3
->list_lock
, l3_key
);
623 * FIXME: This check for BAD_ALIEN_MAGIC
624 * should go away when common slab code is taught to
625 * work even without alien caches.
626 * Currently, non NUMA code returns BAD_ALIEN_MAGIC
627 * for alloc_alien_cache,
629 if (!alc
|| (unsigned long)alc
== BAD_ALIEN_MAGIC
)
633 lockdep_set_class(&alc
[r
]->lock
, alc_key
);
637 static void slab_set_debugobj_lock_classes_node(struct kmem_cache
*cachep
, int node
)
639 slab_set_lock_classes(cachep
, &debugobj_l3_key
, &debugobj_alc_key
, node
);
642 static void slab_set_debugobj_lock_classes(struct kmem_cache
*cachep
)
646 for_each_online_node(node
)
647 slab_set_debugobj_lock_classes_node(cachep
, node
);
650 static void init_node_lock_keys(int q
)
652 struct cache_sizes
*s
= malloc_sizes
;
654 if (g_cpucache_up
< LATE
)
657 for (s
= malloc_sizes
; s
->cs_size
!= ULONG_MAX
; s
++) {
658 struct kmem_list3
*l3
;
660 l3
= s
->cs_cachep
->nodelists
[q
];
661 if (!l3
|| OFF_SLAB(s
->cs_cachep
))
664 slab_set_lock_classes(s
->cs_cachep
, &on_slab_l3_key
,
665 &on_slab_alc_key
, q
);
669 static inline void init_lock_keys(void)
674 init_node_lock_keys(node
);
677 static void init_node_lock_keys(int q
)
681 static inline void init_lock_keys(void)
685 static void slab_set_debugobj_lock_classes_node(struct kmem_cache
*cachep
, int node
)
689 static void slab_set_debugobj_lock_classes(struct kmem_cache
*cachep
)
695 * Guard access to the cache-chain.
697 static DEFINE_MUTEX(cache_chain_mutex
);
698 static struct list_head cache_chain
;
700 static DEFINE_PER_CPU(struct delayed_work
, slab_reap_work
);
702 static inline struct array_cache
*cpu_cache_get(struct kmem_cache
*cachep
)
704 return cachep
->array
[smp_processor_id()];
707 static inline struct kmem_cache
*__find_general_cachep(size_t size
,
710 struct cache_sizes
*csizep
= malloc_sizes
;
713 /* This happens if someone tries to call
714 * kmem_cache_create(), or __kmalloc(), before
715 * the generic caches are initialized.
717 BUG_ON(malloc_sizes
[INDEX_AC
].cs_cachep
== NULL
);
720 return ZERO_SIZE_PTR
;
722 while (size
> csizep
->cs_size
)
726 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
727 * has cs_{dma,}cachep==NULL. Thus no special case
728 * for large kmalloc calls required.
730 #ifdef CONFIG_ZONE_DMA
731 if (unlikely(gfpflags
& GFP_DMA
))
732 return csizep
->cs_dmacachep
;
734 return csizep
->cs_cachep
;
737 static struct kmem_cache
*kmem_find_general_cachep(size_t size
, gfp_t gfpflags
)
739 return __find_general_cachep(size
, gfpflags
);
742 static size_t slab_mgmt_size(size_t nr_objs
, size_t align
)
744 return ALIGN(sizeof(struct slab
)+nr_objs
*sizeof(kmem_bufctl_t
), align
);
748 * Calculate the number of objects and left-over bytes for a given buffer size.
750 static void cache_estimate(unsigned long gfporder
, size_t buffer_size
,
751 size_t align
, int flags
, size_t *left_over
,
756 size_t slab_size
= PAGE_SIZE
<< gfporder
;
759 * The slab management structure can be either off the slab or
760 * on it. For the latter case, the memory allocated for a
764 * - One kmem_bufctl_t for each object
765 * - Padding to respect alignment of @align
766 * - @buffer_size bytes for each object
768 * If the slab management structure is off the slab, then the
769 * alignment will already be calculated into the size. Because
770 * the slabs are all pages aligned, the objects will be at the
771 * correct alignment when allocated.
773 if (flags
& CFLGS_OFF_SLAB
) {
775 nr_objs
= slab_size
/ buffer_size
;
777 if (nr_objs
> SLAB_LIMIT
)
778 nr_objs
= SLAB_LIMIT
;
781 * Ignore padding for the initial guess. The padding
782 * is at most @align-1 bytes, and @buffer_size is at
783 * least @align. In the worst case, this result will
784 * be one greater than the number of objects that fit
785 * into the memory allocation when taking the padding
788 nr_objs
= (slab_size
- sizeof(struct slab
)) /
789 (buffer_size
+ sizeof(kmem_bufctl_t
));
792 * This calculated number will be either the right
793 * amount, or one greater than what we want.
795 if (slab_mgmt_size(nr_objs
, align
) + nr_objs
*buffer_size
799 if (nr_objs
> SLAB_LIMIT
)
800 nr_objs
= SLAB_LIMIT
;
802 mgmt_size
= slab_mgmt_size(nr_objs
, align
);
805 *left_over
= slab_size
- nr_objs
*buffer_size
- mgmt_size
;
808 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
810 static void __slab_error(const char *function
, struct kmem_cache
*cachep
,
813 printk(KERN_ERR
"slab error in %s(): cache `%s': %s\n",
814 function
, cachep
->name
, msg
);
819 * By default on NUMA we use alien caches to stage the freeing of
820 * objects allocated from other nodes. This causes massive memory
821 * inefficiencies when using fake NUMA setup to split memory into a
822 * large number of small nodes, so it can be disabled on the command
826 static int use_alien_caches __read_mostly
= 1;
827 static int __init
noaliencache_setup(char *s
)
829 use_alien_caches
= 0;
832 __setup("noaliencache", noaliencache_setup
);
834 static int __init
slab_max_order_setup(char *str
)
836 get_option(&str
, &slab_max_order
);
837 slab_max_order
= slab_max_order
< 0 ? 0 :
838 min(slab_max_order
, MAX_ORDER
- 1);
839 slab_max_order_set
= true;
843 __setup("slab_max_order=", slab_max_order_setup
);
847 * Special reaping functions for NUMA systems called from cache_reap().
848 * These take care of doing round robin flushing of alien caches (containing
849 * objects freed on different nodes from which they were allocated) and the
850 * flushing of remote pcps by calling drain_node_pages.
852 static DEFINE_PER_CPU(unsigned long, slab_reap_node
);
854 static void init_reap_node(int cpu
)
858 node
= next_node(cpu_to_mem(cpu
), node_online_map
);
859 if (node
== MAX_NUMNODES
)
860 node
= first_node(node_online_map
);
862 per_cpu(slab_reap_node
, cpu
) = node
;
865 static void next_reap_node(void)
867 int node
= __this_cpu_read(slab_reap_node
);
869 node
= next_node(node
, node_online_map
);
870 if (unlikely(node
>= MAX_NUMNODES
))
871 node
= first_node(node_online_map
);
872 __this_cpu_write(slab_reap_node
, node
);
876 #define init_reap_node(cpu) do { } while (0)
877 #define next_reap_node(void) do { } while (0)
881 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
882 * via the workqueue/eventd.
883 * Add the CPU number into the expiration time to minimize the possibility of
884 * the CPUs getting into lockstep and contending for the global cache chain
887 static void __cpuinit
start_cpu_timer(int cpu
)
889 struct delayed_work
*reap_work
= &per_cpu(slab_reap_work
, cpu
);
892 * When this gets called from do_initcalls via cpucache_init(),
893 * init_workqueues() has already run, so keventd will be setup
896 if (keventd_up() && reap_work
->work
.func
== NULL
) {
898 INIT_DELAYED_WORK_DEFERRABLE(reap_work
, cache_reap
);
899 schedule_delayed_work_on(cpu
, reap_work
,
900 __round_jiffies_relative(HZ
, cpu
));
904 static struct array_cache
*alloc_arraycache(int node
, int entries
,
905 int batchcount
, gfp_t gfp
)
907 int memsize
= sizeof(void *) * entries
+ sizeof(struct array_cache
);
908 struct array_cache
*nc
= NULL
;
910 nc
= kmalloc_node(memsize
, gfp
, node
);
912 * The array_cache structures contain pointers to free object.
913 * However, when such objects are allocated or transferred to another
914 * cache the pointers are not cleared and they could be counted as
915 * valid references during a kmemleak scan. Therefore, kmemleak must
916 * not scan such objects.
918 kmemleak_no_scan(nc
);
922 nc
->batchcount
= batchcount
;
924 spin_lock_init(&nc
->lock
);
930 * Transfer objects in one arraycache to another.
931 * Locking must be handled by the caller.
933 * Return the number of entries transferred.
935 static int transfer_objects(struct array_cache
*to
,
936 struct array_cache
*from
, unsigned int max
)
938 /* Figure out how many entries to transfer */
939 int nr
= min3(from
->avail
, max
, to
->limit
- to
->avail
);
944 memcpy(to
->entry
+ to
->avail
, from
->entry
+ from
->avail
-nr
,
954 #define drain_alien_cache(cachep, alien) do { } while (0)
955 #define reap_alien(cachep, l3) do { } while (0)
957 static inline struct array_cache
**alloc_alien_cache(int node
, int limit
, gfp_t gfp
)
959 return (struct array_cache
**)BAD_ALIEN_MAGIC
;
962 static inline void free_alien_cache(struct array_cache
**ac_ptr
)
966 static inline int cache_free_alien(struct kmem_cache
*cachep
, void *objp
)
971 static inline void *alternate_node_alloc(struct kmem_cache
*cachep
,
977 static inline void *____cache_alloc_node(struct kmem_cache
*cachep
,
978 gfp_t flags
, int nodeid
)
983 #else /* CONFIG_NUMA */
985 static void *____cache_alloc_node(struct kmem_cache
*, gfp_t
, int);
986 static void *alternate_node_alloc(struct kmem_cache
*, gfp_t
);
988 static struct array_cache
**alloc_alien_cache(int node
, int limit
, gfp_t gfp
)
990 struct array_cache
**ac_ptr
;
991 int memsize
= sizeof(void *) * nr_node_ids
;
996 ac_ptr
= kzalloc_node(memsize
, gfp
, node
);
999 if (i
== node
|| !node_online(i
))
1001 ac_ptr
[i
] = alloc_arraycache(node
, limit
, 0xbaadf00d, gfp
);
1003 for (i
--; i
>= 0; i
--)
1013 static void free_alien_cache(struct array_cache
**ac_ptr
)
1024 static void __drain_alien_cache(struct kmem_cache
*cachep
,
1025 struct array_cache
*ac
, int node
)
1027 struct kmem_list3
*rl3
= cachep
->nodelists
[node
];
1030 spin_lock(&rl3
->list_lock
);
1032 * Stuff objects into the remote nodes shared array first.
1033 * That way we could avoid the overhead of putting the objects
1034 * into the free lists and getting them back later.
1037 transfer_objects(rl3
->shared
, ac
, ac
->limit
);
1039 free_block(cachep
, ac
->entry
, ac
->avail
, node
);
1041 spin_unlock(&rl3
->list_lock
);
1046 * Called from cache_reap() to regularly drain alien caches round robin.
1048 static void reap_alien(struct kmem_cache
*cachep
, struct kmem_list3
*l3
)
1050 int node
= __this_cpu_read(slab_reap_node
);
1053 struct array_cache
*ac
= l3
->alien
[node
];
1055 if (ac
&& ac
->avail
&& spin_trylock_irq(&ac
->lock
)) {
1056 __drain_alien_cache(cachep
, ac
, node
);
1057 spin_unlock_irq(&ac
->lock
);
1062 static void drain_alien_cache(struct kmem_cache
*cachep
,
1063 struct array_cache
**alien
)
1066 struct array_cache
*ac
;
1067 unsigned long flags
;
1069 for_each_online_node(i
) {
1072 spin_lock_irqsave(&ac
->lock
, flags
);
1073 __drain_alien_cache(cachep
, ac
, i
);
1074 spin_unlock_irqrestore(&ac
->lock
, flags
);
1079 static inline int cache_free_alien(struct kmem_cache
*cachep
, void *objp
)
1081 struct slab
*slabp
= virt_to_slab(objp
);
1082 int nodeid
= slabp
->nodeid
;
1083 struct kmem_list3
*l3
;
1084 struct array_cache
*alien
= NULL
;
1087 node
= numa_mem_id();
1090 * Make sure we are not freeing a object from another node to the array
1091 * cache on this cpu.
1093 if (likely(slabp
->nodeid
== node
))
1096 l3
= cachep
->nodelists
[node
];
1097 STATS_INC_NODEFREES(cachep
);
1098 if (l3
->alien
&& l3
->alien
[nodeid
]) {
1099 alien
= l3
->alien
[nodeid
];
1100 spin_lock(&alien
->lock
);
1101 if (unlikely(alien
->avail
== alien
->limit
)) {
1102 STATS_INC_ACOVERFLOW(cachep
);
1103 __drain_alien_cache(cachep
, alien
, nodeid
);
1105 alien
->entry
[alien
->avail
++] = objp
;
1106 spin_unlock(&alien
->lock
);
1108 spin_lock(&(cachep
->nodelists
[nodeid
])->list_lock
);
1109 free_block(cachep
, &objp
, 1, nodeid
);
1110 spin_unlock(&(cachep
->nodelists
[nodeid
])->list_lock
);
1117 * Allocates and initializes nodelists for a node on each slab cache, used for
1118 * either memory or cpu hotplug. If memory is being hot-added, the kmem_list3
1119 * will be allocated off-node since memory is not yet online for the new node.
1120 * When hotplugging memory or a cpu, existing nodelists are not replaced if
1123 * Must hold cache_chain_mutex.
1125 static int init_cache_nodelists_node(int node
)
1127 struct kmem_cache
*cachep
;
1128 struct kmem_list3
*l3
;
1129 const int memsize
= sizeof(struct kmem_list3
);
1131 list_for_each_entry(cachep
, &cache_chain
, list
) {
1133 * Set up the size64 kmemlist for cpu before we can
1134 * begin anything. Make sure some other cpu on this
1135 * node has not already allocated this
1137 if (!cachep
->nodelists
[node
]) {
1138 l3
= kmalloc_node(memsize
, GFP_KERNEL
, node
);
1141 kmem_list3_init(l3
);
1142 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
+
1143 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
1146 * The l3s don't come and go as CPUs come and
1147 * go. cache_chain_mutex is sufficient
1150 cachep
->nodelists
[node
] = l3
;
1153 spin_lock_irq(&cachep
->nodelists
[node
]->list_lock
);
1154 cachep
->nodelists
[node
]->free_limit
=
1155 (1 + nr_cpus_node(node
)) *
1156 cachep
->batchcount
+ cachep
->num
;
1157 spin_unlock_irq(&cachep
->nodelists
[node
]->list_lock
);
1162 static void __cpuinit
cpuup_canceled(long cpu
)
1164 struct kmem_cache
*cachep
;
1165 struct kmem_list3
*l3
= NULL
;
1166 int node
= cpu_to_mem(cpu
);
1167 const struct cpumask
*mask
= cpumask_of_node(node
);
1169 list_for_each_entry(cachep
, &cache_chain
, list
) {
1170 struct array_cache
*nc
;
1171 struct array_cache
*shared
;
1172 struct array_cache
**alien
;
1174 /* cpu is dead; no one can alloc from it. */
1175 nc
= cachep
->array
[cpu
];
1176 cachep
->array
[cpu
] = NULL
;
1177 l3
= cachep
->nodelists
[node
];
1180 goto free_array_cache
;
1182 spin_lock_irq(&l3
->list_lock
);
1184 /* Free limit for this kmem_list3 */
1185 l3
->free_limit
-= cachep
->batchcount
;
1187 free_block(cachep
, nc
->entry
, nc
->avail
, node
);
1189 if (!cpumask_empty(mask
)) {
1190 spin_unlock_irq(&l3
->list_lock
);
1191 goto free_array_cache
;
1194 shared
= l3
->shared
;
1196 free_block(cachep
, shared
->entry
,
1197 shared
->avail
, node
);
1204 spin_unlock_irq(&l3
->list_lock
);
1208 drain_alien_cache(cachep
, alien
);
1209 free_alien_cache(alien
);
1215 * In the previous loop, all the objects were freed to
1216 * the respective cache's slabs, now we can go ahead and
1217 * shrink each nodelist to its limit.
1219 list_for_each_entry(cachep
, &cache_chain
, list
) {
1220 l3
= cachep
->nodelists
[node
];
1223 drain_freelist(cachep
, l3
, l3
->free_objects
);
1227 static int __cpuinit
cpuup_prepare(long cpu
)
1229 struct kmem_cache
*cachep
;
1230 struct kmem_list3
*l3
= NULL
;
1231 int node
= cpu_to_mem(cpu
);
1235 * We need to do this right in the beginning since
1236 * alloc_arraycache's are going to use this list.
1237 * kmalloc_node allows us to add the slab to the right
1238 * kmem_list3 and not this cpu's kmem_list3
1240 err
= init_cache_nodelists_node(node
);
1245 * Now we can go ahead with allocating the shared arrays and
1248 list_for_each_entry(cachep
, &cache_chain
, list
) {
1249 struct array_cache
*nc
;
1250 struct array_cache
*shared
= NULL
;
1251 struct array_cache
**alien
= NULL
;
1253 nc
= alloc_arraycache(node
, cachep
->limit
,
1254 cachep
->batchcount
, GFP_KERNEL
);
1257 if (cachep
->shared
) {
1258 shared
= alloc_arraycache(node
,
1259 cachep
->shared
* cachep
->batchcount
,
1260 0xbaadf00d, GFP_KERNEL
);
1266 if (use_alien_caches
) {
1267 alien
= alloc_alien_cache(node
, cachep
->limit
, GFP_KERNEL
);
1274 cachep
->array
[cpu
] = nc
;
1275 l3
= cachep
->nodelists
[node
];
1278 spin_lock_irq(&l3
->list_lock
);
1281 * We are serialised from CPU_DEAD or
1282 * CPU_UP_CANCELLED by the cpucontrol lock
1284 l3
->shared
= shared
;
1293 spin_unlock_irq(&l3
->list_lock
);
1295 free_alien_cache(alien
);
1296 if (cachep
->flags
& SLAB_DEBUG_OBJECTS
)
1297 slab_set_debugobj_lock_classes_node(cachep
, node
);
1299 init_node_lock_keys(node
);
1303 cpuup_canceled(cpu
);
1307 static int __cpuinit
cpuup_callback(struct notifier_block
*nfb
,
1308 unsigned long action
, void *hcpu
)
1310 long cpu
= (long)hcpu
;
1314 case CPU_UP_PREPARE
:
1315 case CPU_UP_PREPARE_FROZEN
:
1316 mutex_lock(&cache_chain_mutex
);
1317 err
= cpuup_prepare(cpu
);
1318 mutex_unlock(&cache_chain_mutex
);
1321 case CPU_ONLINE_FROZEN
:
1322 start_cpu_timer(cpu
);
1324 #ifdef CONFIG_HOTPLUG_CPU
1325 case CPU_DOWN_PREPARE
:
1326 case CPU_DOWN_PREPARE_FROZEN
:
1328 * Shutdown cache reaper. Note that the cache_chain_mutex is
1329 * held so that if cache_reap() is invoked it cannot do
1330 * anything expensive but will only modify reap_work
1331 * and reschedule the timer.
1333 cancel_delayed_work_sync(&per_cpu(slab_reap_work
, cpu
));
1334 /* Now the cache_reaper is guaranteed to be not running. */
1335 per_cpu(slab_reap_work
, cpu
).work
.func
= NULL
;
1337 case CPU_DOWN_FAILED
:
1338 case CPU_DOWN_FAILED_FROZEN
:
1339 start_cpu_timer(cpu
);
1342 case CPU_DEAD_FROZEN
:
1344 * Even if all the cpus of a node are down, we don't free the
1345 * kmem_list3 of any cache. This to avoid a race between
1346 * cpu_down, and a kmalloc allocation from another cpu for
1347 * memory from the node of the cpu going down. The list3
1348 * structure is usually allocated from kmem_cache_create() and
1349 * gets destroyed at kmem_cache_destroy().
1353 case CPU_UP_CANCELED
:
1354 case CPU_UP_CANCELED_FROZEN
:
1355 mutex_lock(&cache_chain_mutex
);
1356 cpuup_canceled(cpu
);
1357 mutex_unlock(&cache_chain_mutex
);
1360 return notifier_from_errno(err
);
1363 static struct notifier_block __cpuinitdata cpucache_notifier
= {
1364 &cpuup_callback
, NULL
, 0
1367 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1369 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1370 * Returns -EBUSY if all objects cannot be drained so that the node is not
1373 * Must hold cache_chain_mutex.
1375 static int __meminit
drain_cache_nodelists_node(int node
)
1377 struct kmem_cache
*cachep
;
1380 list_for_each_entry(cachep
, &cache_chain
, list
) {
1381 struct kmem_list3
*l3
;
1383 l3
= cachep
->nodelists
[node
];
1387 drain_freelist(cachep
, l3
, l3
->free_objects
);
1389 if (!list_empty(&l3
->slabs_full
) ||
1390 !list_empty(&l3
->slabs_partial
)) {
1398 static int __meminit
slab_memory_callback(struct notifier_block
*self
,
1399 unsigned long action
, void *arg
)
1401 struct memory_notify
*mnb
= arg
;
1405 nid
= mnb
->status_change_nid
;
1410 case MEM_GOING_ONLINE
:
1411 mutex_lock(&cache_chain_mutex
);
1412 ret
= init_cache_nodelists_node(nid
);
1413 mutex_unlock(&cache_chain_mutex
);
1415 case MEM_GOING_OFFLINE
:
1416 mutex_lock(&cache_chain_mutex
);
1417 ret
= drain_cache_nodelists_node(nid
);
1418 mutex_unlock(&cache_chain_mutex
);
1422 case MEM_CANCEL_ONLINE
:
1423 case MEM_CANCEL_OFFLINE
:
1427 return notifier_from_errno(ret
);
1429 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1432 * swap the static kmem_list3 with kmalloced memory
1434 static void __init
init_list(struct kmem_cache
*cachep
, struct kmem_list3
*list
,
1437 struct kmem_list3
*ptr
;
1439 ptr
= kmalloc_node(sizeof(struct kmem_list3
), GFP_NOWAIT
, nodeid
);
1442 memcpy(ptr
, list
, sizeof(struct kmem_list3
));
1444 * Do not assume that spinlocks can be initialized via memcpy:
1446 spin_lock_init(&ptr
->list_lock
);
1448 MAKE_ALL_LISTS(cachep
, ptr
, nodeid
);
1449 cachep
->nodelists
[nodeid
] = ptr
;
1453 * For setting up all the kmem_list3s for cache whose buffer_size is same as
1454 * size of kmem_list3.
1456 static void __init
set_up_list3s(struct kmem_cache
*cachep
, int index
)
1460 for_each_online_node(node
) {
1461 cachep
->nodelists
[node
] = &initkmem_list3
[index
+ node
];
1462 cachep
->nodelists
[node
]->next_reap
= jiffies
+
1464 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
1469 * Initialisation. Called after the page allocator have been initialised and
1470 * before smp_init().
1472 void __init
kmem_cache_init(void)
1475 struct cache_sizes
*sizes
;
1476 struct cache_names
*names
;
1481 if (num_possible_nodes() == 1)
1482 use_alien_caches
= 0;
1484 for (i
= 0; i
< NUM_INIT_LISTS
; i
++) {
1485 kmem_list3_init(&initkmem_list3
[i
]);
1486 if (i
< MAX_NUMNODES
)
1487 cache_cache
.nodelists
[i
] = NULL
;
1489 set_up_list3s(&cache_cache
, CACHE_CACHE
);
1492 * Fragmentation resistance on low memory - only use bigger
1493 * page orders on machines with more than 32MB of memory if
1494 * not overridden on the command line.
1496 if (!slab_max_order_set
&& totalram_pages
> (32 << 20) >> PAGE_SHIFT
)
1497 slab_max_order
= SLAB_MAX_ORDER_HI
;
1499 /* Bootstrap is tricky, because several objects are allocated
1500 * from caches that do not exist yet:
1501 * 1) initialize the cache_cache cache: it contains the struct
1502 * kmem_cache structures of all caches, except cache_cache itself:
1503 * cache_cache is statically allocated.
1504 * Initially an __init data area is used for the head array and the
1505 * kmem_list3 structures, it's replaced with a kmalloc allocated
1506 * array at the end of the bootstrap.
1507 * 2) Create the first kmalloc cache.
1508 * The struct kmem_cache for the new cache is allocated normally.
1509 * An __init data area is used for the head array.
1510 * 3) Create the remaining kmalloc caches, with minimally sized
1512 * 4) Replace the __init data head arrays for cache_cache and the first
1513 * kmalloc cache with kmalloc allocated arrays.
1514 * 5) Replace the __init data for kmem_list3 for cache_cache and
1515 * the other cache's with kmalloc allocated memory.
1516 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1519 node
= numa_mem_id();
1521 /* 1) create the cache_cache */
1522 INIT_LIST_HEAD(&cache_chain
);
1523 list_add(&cache_cache
.list
, &cache_chain
);
1524 cache_cache
.colour_off
= cache_line_size();
1525 cache_cache
.array
[smp_processor_id()] = &initarray_cache
.cache
;
1526 cache_cache
.nodelists
[node
] = &initkmem_list3
[CACHE_CACHE
+ node
];
1529 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1531 cache_cache
.size
= offsetof(struct kmem_cache
, array
[nr_cpu_ids
]) +
1532 nr_node_ids
* sizeof(struct kmem_list3
*);
1533 cache_cache
.object_size
= cache_cache
.size
;
1534 cache_cache
.size
= ALIGN(cache_cache
.size
,
1536 cache_cache
.reciprocal_buffer_size
=
1537 reciprocal_value(cache_cache
.size
);
1539 for (order
= 0; order
< MAX_ORDER
; order
++) {
1540 cache_estimate(order
, cache_cache
.size
,
1541 cache_line_size(), 0, &left_over
, &cache_cache
.num
);
1542 if (cache_cache
.num
)
1545 BUG_ON(!cache_cache
.num
);
1546 cache_cache
.gfporder
= order
;
1547 cache_cache
.colour
= left_over
/ cache_cache
.colour_off
;
1548 cache_cache
.slab_size
= ALIGN(cache_cache
.num
* sizeof(kmem_bufctl_t
) +
1549 sizeof(struct slab
), cache_line_size());
1551 /* 2+3) create the kmalloc caches */
1552 sizes
= malloc_sizes
;
1553 names
= cache_names
;
1556 * Initialize the caches that provide memory for the array cache and the
1557 * kmem_list3 structures first. Without this, further allocations will
1561 sizes
[INDEX_AC
].cs_cachep
= kmem_cache_create(names
[INDEX_AC
].name
,
1562 sizes
[INDEX_AC
].cs_size
,
1563 ARCH_KMALLOC_MINALIGN
,
1564 ARCH_KMALLOC_FLAGS
|SLAB_PANIC
,
1567 if (INDEX_AC
!= INDEX_L3
) {
1568 sizes
[INDEX_L3
].cs_cachep
=
1569 kmem_cache_create(names
[INDEX_L3
].name
,
1570 sizes
[INDEX_L3
].cs_size
,
1571 ARCH_KMALLOC_MINALIGN
,
1572 ARCH_KMALLOC_FLAGS
|SLAB_PANIC
,
1576 slab_early_init
= 0;
1578 while (sizes
->cs_size
!= ULONG_MAX
) {
1580 * For performance, all the general caches are L1 aligned.
1581 * This should be particularly beneficial on SMP boxes, as it
1582 * eliminates "false sharing".
1583 * Note for systems short on memory removing the alignment will
1584 * allow tighter packing of the smaller caches.
1586 if (!sizes
->cs_cachep
) {
1587 sizes
->cs_cachep
= kmem_cache_create(names
->name
,
1589 ARCH_KMALLOC_MINALIGN
,
1590 ARCH_KMALLOC_FLAGS
|SLAB_PANIC
,
1593 #ifdef CONFIG_ZONE_DMA
1594 sizes
->cs_dmacachep
= kmem_cache_create(
1597 ARCH_KMALLOC_MINALIGN
,
1598 ARCH_KMALLOC_FLAGS
|SLAB_CACHE_DMA
|
1605 /* 4) Replace the bootstrap head arrays */
1607 struct array_cache
*ptr
;
1609 ptr
= kmalloc(sizeof(struct arraycache_init
), GFP_NOWAIT
);
1611 BUG_ON(cpu_cache_get(&cache_cache
) != &initarray_cache
.cache
);
1612 memcpy(ptr
, cpu_cache_get(&cache_cache
),
1613 sizeof(struct arraycache_init
));
1615 * Do not assume that spinlocks can be initialized via memcpy:
1617 spin_lock_init(&ptr
->lock
);
1619 cache_cache
.array
[smp_processor_id()] = ptr
;
1621 ptr
= kmalloc(sizeof(struct arraycache_init
), GFP_NOWAIT
);
1623 BUG_ON(cpu_cache_get(malloc_sizes
[INDEX_AC
].cs_cachep
)
1624 != &initarray_generic
.cache
);
1625 memcpy(ptr
, cpu_cache_get(malloc_sizes
[INDEX_AC
].cs_cachep
),
1626 sizeof(struct arraycache_init
));
1628 * Do not assume that spinlocks can be initialized via memcpy:
1630 spin_lock_init(&ptr
->lock
);
1632 malloc_sizes
[INDEX_AC
].cs_cachep
->array
[smp_processor_id()] =
1635 /* 5) Replace the bootstrap kmem_list3's */
1639 for_each_online_node(nid
) {
1640 init_list(&cache_cache
, &initkmem_list3
[CACHE_CACHE
+ nid
], nid
);
1642 init_list(malloc_sizes
[INDEX_AC
].cs_cachep
,
1643 &initkmem_list3
[SIZE_AC
+ nid
], nid
);
1645 if (INDEX_AC
!= INDEX_L3
) {
1646 init_list(malloc_sizes
[INDEX_L3
].cs_cachep
,
1647 &initkmem_list3
[SIZE_L3
+ nid
], nid
);
1652 g_cpucache_up
= EARLY
;
1655 void __init
kmem_cache_init_late(void)
1657 struct kmem_cache
*cachep
;
1659 g_cpucache_up
= LATE
;
1661 /* Annotate slab for lockdep -- annotate the malloc caches */
1664 /* 6) resize the head arrays to their final sizes */
1665 mutex_lock(&cache_chain_mutex
);
1666 list_for_each_entry(cachep
, &cache_chain
, list
)
1667 if (enable_cpucache(cachep
, GFP_NOWAIT
))
1669 mutex_unlock(&cache_chain_mutex
);
1672 g_cpucache_up
= FULL
;
1675 * Register a cpu startup notifier callback that initializes
1676 * cpu_cache_get for all new cpus
1678 register_cpu_notifier(&cpucache_notifier
);
1682 * Register a memory hotplug callback that initializes and frees
1685 hotplug_memory_notifier(slab_memory_callback
, SLAB_CALLBACK_PRI
);
1689 * The reap timers are started later, with a module init call: That part
1690 * of the kernel is not yet operational.
1694 static int __init
cpucache_init(void)
1699 * Register the timers that return unneeded pages to the page allocator
1701 for_each_online_cpu(cpu
)
1702 start_cpu_timer(cpu
);
1705 __initcall(cpucache_init
);
1707 static noinline
void
1708 slab_out_of_memory(struct kmem_cache
*cachep
, gfp_t gfpflags
, int nodeid
)
1710 struct kmem_list3
*l3
;
1712 unsigned long flags
;
1716 "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1718 printk(KERN_WARNING
" cache: %s, object size: %d, order: %d\n",
1719 cachep
->name
, cachep
->size
, cachep
->gfporder
);
1721 for_each_online_node(node
) {
1722 unsigned long active_objs
= 0, num_objs
= 0, free_objects
= 0;
1723 unsigned long active_slabs
= 0, num_slabs
= 0;
1725 l3
= cachep
->nodelists
[node
];
1729 spin_lock_irqsave(&l3
->list_lock
, flags
);
1730 list_for_each_entry(slabp
, &l3
->slabs_full
, list
) {
1731 active_objs
+= cachep
->num
;
1734 list_for_each_entry(slabp
, &l3
->slabs_partial
, list
) {
1735 active_objs
+= slabp
->inuse
;
1738 list_for_each_entry(slabp
, &l3
->slabs_free
, list
)
1741 free_objects
+= l3
->free_objects
;
1742 spin_unlock_irqrestore(&l3
->list_lock
, flags
);
1744 num_slabs
+= active_slabs
;
1745 num_objs
= num_slabs
* cachep
->num
;
1747 " node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
1748 node
, active_slabs
, num_slabs
, active_objs
, num_objs
,
1754 * Interface to system's page allocator. No need to hold the cache-lock.
1756 * If we requested dmaable memory, we will get it. Even if we
1757 * did not request dmaable memory, we might get it, but that
1758 * would be relatively rare and ignorable.
1760 static void *kmem_getpages(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
1768 * Nommu uses slab's for process anonymous memory allocations, and thus
1769 * requires __GFP_COMP to properly refcount higher order allocations
1771 flags
|= __GFP_COMP
;
1774 flags
|= cachep
->gfpflags
;
1775 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1776 flags
|= __GFP_RECLAIMABLE
;
1778 page
= alloc_pages_exact_node(nodeid
, flags
| __GFP_NOTRACK
, cachep
->gfporder
);
1780 if (!(flags
& __GFP_NOWARN
) && printk_ratelimit())
1781 slab_out_of_memory(cachep
, flags
, nodeid
);
1785 nr_pages
= (1 << cachep
->gfporder
);
1786 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1787 add_zone_page_state(page_zone(page
),
1788 NR_SLAB_RECLAIMABLE
, nr_pages
);
1790 add_zone_page_state(page_zone(page
),
1791 NR_SLAB_UNRECLAIMABLE
, nr_pages
);
1792 for (i
= 0; i
< nr_pages
; i
++)
1793 __SetPageSlab(page
+ i
);
1795 if (kmemcheck_enabled
&& !(cachep
->flags
& SLAB_NOTRACK
)) {
1796 kmemcheck_alloc_shadow(page
, cachep
->gfporder
, flags
, nodeid
);
1799 kmemcheck_mark_uninitialized_pages(page
, nr_pages
);
1801 kmemcheck_mark_unallocated_pages(page
, nr_pages
);
1804 return page_address(page
);
1808 * Interface to system's page release.
1810 static void kmem_freepages(struct kmem_cache
*cachep
, void *addr
)
1812 unsigned long i
= (1 << cachep
->gfporder
);
1813 struct page
*page
= virt_to_page(addr
);
1814 const unsigned long nr_freed
= i
;
1816 kmemcheck_free_shadow(page
, cachep
->gfporder
);
1818 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1819 sub_zone_page_state(page_zone(page
),
1820 NR_SLAB_RECLAIMABLE
, nr_freed
);
1822 sub_zone_page_state(page_zone(page
),
1823 NR_SLAB_UNRECLAIMABLE
, nr_freed
);
1825 BUG_ON(!PageSlab(page
));
1826 __ClearPageSlab(page
);
1829 if (current
->reclaim_state
)
1830 current
->reclaim_state
->reclaimed_slab
+= nr_freed
;
1831 free_pages((unsigned long)addr
, cachep
->gfporder
);
1834 static void kmem_rcu_free(struct rcu_head
*head
)
1836 struct slab_rcu
*slab_rcu
= (struct slab_rcu
*)head
;
1837 struct kmem_cache
*cachep
= slab_rcu
->cachep
;
1839 kmem_freepages(cachep
, slab_rcu
->addr
);
1840 if (OFF_SLAB(cachep
))
1841 kmem_cache_free(cachep
->slabp_cache
, slab_rcu
);
1846 #ifdef CONFIG_DEBUG_PAGEALLOC
1847 static void store_stackinfo(struct kmem_cache
*cachep
, unsigned long *addr
,
1848 unsigned long caller
)
1850 int size
= cachep
->object_size
;
1852 addr
= (unsigned long *)&((char *)addr
)[obj_offset(cachep
)];
1854 if (size
< 5 * sizeof(unsigned long))
1857 *addr
++ = 0x12345678;
1859 *addr
++ = smp_processor_id();
1860 size
-= 3 * sizeof(unsigned long);
1862 unsigned long *sptr
= &caller
;
1863 unsigned long svalue
;
1865 while (!kstack_end(sptr
)) {
1867 if (kernel_text_address(svalue
)) {
1869 size
-= sizeof(unsigned long);
1870 if (size
<= sizeof(unsigned long))
1876 *addr
++ = 0x87654321;
1880 static void poison_obj(struct kmem_cache
*cachep
, void *addr
, unsigned char val
)
1882 int size
= cachep
->object_size
;
1883 addr
= &((char *)addr
)[obj_offset(cachep
)];
1885 memset(addr
, val
, size
);
1886 *(unsigned char *)(addr
+ size
- 1) = POISON_END
;
1889 static void dump_line(char *data
, int offset
, int limit
)
1892 unsigned char error
= 0;
1895 printk(KERN_ERR
"%03x: ", offset
);
1896 for (i
= 0; i
< limit
; i
++) {
1897 if (data
[offset
+ i
] != POISON_FREE
) {
1898 error
= data
[offset
+ i
];
1902 print_hex_dump(KERN_CONT
, "", 0, 16, 1,
1903 &data
[offset
], limit
, 1);
1905 if (bad_count
== 1) {
1906 error
^= POISON_FREE
;
1907 if (!(error
& (error
- 1))) {
1908 printk(KERN_ERR
"Single bit error detected. Probably "
1911 printk(KERN_ERR
"Run memtest86+ or a similar memory "
1914 printk(KERN_ERR
"Run a memory test tool.\n");
1923 static void print_objinfo(struct kmem_cache
*cachep
, void *objp
, int lines
)
1928 if (cachep
->flags
& SLAB_RED_ZONE
) {
1929 printk(KERN_ERR
"Redzone: 0x%llx/0x%llx.\n",
1930 *dbg_redzone1(cachep
, objp
),
1931 *dbg_redzone2(cachep
, objp
));
1934 if (cachep
->flags
& SLAB_STORE_USER
) {
1935 printk(KERN_ERR
"Last user: [<%p>]",
1936 *dbg_userword(cachep
, objp
));
1937 print_symbol("(%s)",
1938 (unsigned long)*dbg_userword(cachep
, objp
));
1941 realobj
= (char *)objp
+ obj_offset(cachep
);
1942 size
= cachep
->object_size
;
1943 for (i
= 0; i
< size
&& lines
; i
+= 16, lines
--) {
1946 if (i
+ limit
> size
)
1948 dump_line(realobj
, i
, limit
);
1952 static void check_poison_obj(struct kmem_cache
*cachep
, void *objp
)
1958 realobj
= (char *)objp
+ obj_offset(cachep
);
1959 size
= cachep
->object_size
;
1961 for (i
= 0; i
< size
; i
++) {
1962 char exp
= POISON_FREE
;
1965 if (realobj
[i
] != exp
) {
1971 "Slab corruption (%s): %s start=%p, len=%d\n",
1972 print_tainted(), cachep
->name
, realobj
, size
);
1973 print_objinfo(cachep
, objp
, 0);
1975 /* Hexdump the affected line */
1978 if (i
+ limit
> size
)
1980 dump_line(realobj
, i
, limit
);
1983 /* Limit to 5 lines */
1989 /* Print some data about the neighboring objects, if they
1992 struct slab
*slabp
= virt_to_slab(objp
);
1995 objnr
= obj_to_index(cachep
, slabp
, objp
);
1997 objp
= index_to_obj(cachep
, slabp
, objnr
- 1);
1998 realobj
= (char *)objp
+ obj_offset(cachep
);
1999 printk(KERN_ERR
"Prev obj: start=%p, len=%d\n",
2001 print_objinfo(cachep
, objp
, 2);
2003 if (objnr
+ 1 < cachep
->num
) {
2004 objp
= index_to_obj(cachep
, slabp
, objnr
+ 1);
2005 realobj
= (char *)objp
+ obj_offset(cachep
);
2006 printk(KERN_ERR
"Next obj: start=%p, len=%d\n",
2008 print_objinfo(cachep
, objp
, 2);
2015 static void slab_destroy_debugcheck(struct kmem_cache
*cachep
, struct slab
*slabp
)
2018 for (i
= 0; i
< cachep
->num
; i
++) {
2019 void *objp
= index_to_obj(cachep
, slabp
, i
);
2021 if (cachep
->flags
& SLAB_POISON
) {
2022 #ifdef CONFIG_DEBUG_PAGEALLOC
2023 if (cachep
->size
% PAGE_SIZE
== 0 &&
2025 kernel_map_pages(virt_to_page(objp
),
2026 cachep
->size
/ PAGE_SIZE
, 1);
2028 check_poison_obj(cachep
, objp
);
2030 check_poison_obj(cachep
, objp
);
2033 if (cachep
->flags
& SLAB_RED_ZONE
) {
2034 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
2035 slab_error(cachep
, "start of a freed object "
2037 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
2038 slab_error(cachep
, "end of a freed object "
2044 static void slab_destroy_debugcheck(struct kmem_cache
*cachep
, struct slab
*slabp
)
2050 * slab_destroy - destroy and release all objects in a slab
2051 * @cachep: cache pointer being destroyed
2052 * @slabp: slab pointer being destroyed
2054 * Destroy all the objs in a slab, and release the mem back to the system.
2055 * Before calling the slab must have been unlinked from the cache. The
2056 * cache-lock is not held/needed.
2058 static void slab_destroy(struct kmem_cache
*cachep
, struct slab
*slabp
)
2060 void *addr
= slabp
->s_mem
- slabp
->colouroff
;
2062 slab_destroy_debugcheck(cachep
, slabp
);
2063 if (unlikely(cachep
->flags
& SLAB_DESTROY_BY_RCU
)) {
2064 struct slab_rcu
*slab_rcu
;
2066 slab_rcu
= (struct slab_rcu
*)slabp
;
2067 slab_rcu
->cachep
= cachep
;
2068 slab_rcu
->addr
= addr
;
2069 call_rcu(&slab_rcu
->head
, kmem_rcu_free
);
2071 kmem_freepages(cachep
, addr
);
2072 if (OFF_SLAB(cachep
))
2073 kmem_cache_free(cachep
->slabp_cache
, slabp
);
2077 static void __kmem_cache_destroy(struct kmem_cache
*cachep
)
2080 struct kmem_list3
*l3
;
2082 for_each_online_cpu(i
)
2083 kfree(cachep
->array
[i
]);
2085 /* NUMA: free the list3 structures */
2086 for_each_online_node(i
) {
2087 l3
= cachep
->nodelists
[i
];
2090 free_alien_cache(l3
->alien
);
2094 kmem_cache_free(&cache_cache
, cachep
);
2099 * calculate_slab_order - calculate size (page order) of slabs
2100 * @cachep: pointer to the cache that is being created
2101 * @size: size of objects to be created in this cache.
2102 * @align: required alignment for the objects.
2103 * @flags: slab allocation flags
2105 * Also calculates the number of objects per slab.
2107 * This could be made much more intelligent. For now, try to avoid using
2108 * high order pages for slabs. When the gfp() functions are more friendly
2109 * towards high-order requests, this should be changed.
2111 static size_t calculate_slab_order(struct kmem_cache
*cachep
,
2112 size_t size
, size_t align
, unsigned long flags
)
2114 unsigned long offslab_limit
;
2115 size_t left_over
= 0;
2118 for (gfporder
= 0; gfporder
<= KMALLOC_MAX_ORDER
; gfporder
++) {
2122 cache_estimate(gfporder
, size
, align
, flags
, &remainder
, &num
);
2126 if (flags
& CFLGS_OFF_SLAB
) {
2128 * Max number of objs-per-slab for caches which
2129 * use off-slab slabs. Needed to avoid a possible
2130 * looping condition in cache_grow().
2132 offslab_limit
= size
- sizeof(struct slab
);
2133 offslab_limit
/= sizeof(kmem_bufctl_t
);
2135 if (num
> offslab_limit
)
2139 /* Found something acceptable - save it away */
2141 cachep
->gfporder
= gfporder
;
2142 left_over
= remainder
;
2145 * A VFS-reclaimable slab tends to have most allocations
2146 * as GFP_NOFS and we really don't want to have to be allocating
2147 * higher-order pages when we are unable to shrink dcache.
2149 if (flags
& SLAB_RECLAIM_ACCOUNT
)
2153 * Large number of objects is good, but very large slabs are
2154 * currently bad for the gfp()s.
2156 if (gfporder
>= slab_max_order
)
2160 * Acceptable internal fragmentation?
2162 if (left_over
* 8 <= (PAGE_SIZE
<< gfporder
))
2168 static int __init_refok
setup_cpu_cache(struct kmem_cache
*cachep
, gfp_t gfp
)
2170 if (g_cpucache_up
== FULL
)
2171 return enable_cpucache(cachep
, gfp
);
2173 if (g_cpucache_up
== NONE
) {
2175 * Note: the first kmem_cache_create must create the cache
2176 * that's used by kmalloc(24), otherwise the creation of
2177 * further caches will BUG().
2179 cachep
->array
[smp_processor_id()] = &initarray_generic
.cache
;
2182 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
2183 * the first cache, then we need to set up all its list3s,
2184 * otherwise the creation of further caches will BUG().
2186 set_up_list3s(cachep
, SIZE_AC
);
2187 if (INDEX_AC
== INDEX_L3
)
2188 g_cpucache_up
= PARTIAL_L3
;
2190 g_cpucache_up
= PARTIAL_AC
;
2192 cachep
->array
[smp_processor_id()] =
2193 kmalloc(sizeof(struct arraycache_init
), gfp
);
2195 if (g_cpucache_up
== PARTIAL_AC
) {
2196 set_up_list3s(cachep
, SIZE_L3
);
2197 g_cpucache_up
= PARTIAL_L3
;
2200 for_each_online_node(node
) {
2201 cachep
->nodelists
[node
] =
2202 kmalloc_node(sizeof(struct kmem_list3
),
2204 BUG_ON(!cachep
->nodelists
[node
]);
2205 kmem_list3_init(cachep
->nodelists
[node
]);
2209 cachep
->nodelists
[numa_mem_id()]->next_reap
=
2210 jiffies
+ REAPTIMEOUT_LIST3
+
2211 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
2213 cpu_cache_get(cachep
)->avail
= 0;
2214 cpu_cache_get(cachep
)->limit
= BOOT_CPUCACHE_ENTRIES
;
2215 cpu_cache_get(cachep
)->batchcount
= 1;
2216 cpu_cache_get(cachep
)->touched
= 0;
2217 cachep
->batchcount
= 1;
2218 cachep
->limit
= BOOT_CPUCACHE_ENTRIES
;
2223 * kmem_cache_create - Create a cache.
2224 * @name: A string which is used in /proc/slabinfo to identify this cache.
2225 * @size: The size of objects to be created in this cache.
2226 * @align: The required alignment for the objects.
2227 * @flags: SLAB flags
2228 * @ctor: A constructor for the objects.
2230 * Returns a ptr to the cache on success, NULL on failure.
2231 * Cannot be called within a int, but can be interrupted.
2232 * The @ctor is run when new pages are allocated by the cache.
2234 * @name must be valid until the cache is destroyed. This implies that
2235 * the module calling this has to destroy the cache before getting unloaded.
2239 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2240 * to catch references to uninitialised memory.
2242 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2243 * for buffer overruns.
2245 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2246 * cacheline. This can be beneficial if you're counting cycles as closely
2250 kmem_cache_create (const char *name
, size_t size
, size_t align
,
2251 unsigned long flags
, void (*ctor
)(void *))
2253 size_t left_over
, slab_size
, ralign
;
2254 struct kmem_cache
*cachep
= NULL
, *pc
;
2258 * Sanity checks... these are all serious usage bugs.
2260 if (!name
|| in_interrupt() || (size
< BYTES_PER_WORD
) ||
2261 size
> KMALLOC_MAX_SIZE
) {
2262 printk(KERN_ERR
"%s: Early error in slab %s\n", __func__
,
2268 * We use cache_chain_mutex to ensure a consistent view of
2269 * cpu_online_mask as well. Please see cpuup_callback
2271 if (slab_is_available()) {
2273 mutex_lock(&cache_chain_mutex
);
2276 list_for_each_entry(pc
, &cache_chain
, list
) {
2281 * This happens when the module gets unloaded and doesn't
2282 * destroy its slab cache and no-one else reuses the vmalloc
2283 * area of the module. Print a warning.
2285 res
= probe_kernel_address(pc
->name
, tmp
);
2288 "SLAB: cache with size %d has lost its name\n",
2293 if (!strcmp(pc
->name
, name
)) {
2295 "kmem_cache_create: duplicate cache %s\n", name
);
2302 WARN_ON(strchr(name
, ' ')); /* It confuses parsers */
2305 * Enable redzoning and last user accounting, except for caches with
2306 * large objects, if the increased size would increase the object size
2307 * above the next power of two: caches with object sizes just above a
2308 * power of two have a significant amount of internal fragmentation.
2310 if (size
< 4096 || fls(size
- 1) == fls(size
-1 + REDZONE_ALIGN
+
2311 2 * sizeof(unsigned long long)))
2312 flags
|= SLAB_RED_ZONE
| SLAB_STORE_USER
;
2313 if (!(flags
& SLAB_DESTROY_BY_RCU
))
2314 flags
|= SLAB_POISON
;
2316 if (flags
& SLAB_DESTROY_BY_RCU
)
2317 BUG_ON(flags
& SLAB_POISON
);
2320 * Always checks flags, a caller might be expecting debug support which
2323 BUG_ON(flags
& ~CREATE_MASK
);
2326 * Check that size is in terms of words. This is needed to avoid
2327 * unaligned accesses for some archs when redzoning is used, and makes
2328 * sure any on-slab bufctl's are also correctly aligned.
2330 if (size
& (BYTES_PER_WORD
- 1)) {
2331 size
+= (BYTES_PER_WORD
- 1);
2332 size
&= ~(BYTES_PER_WORD
- 1);
2335 /* calculate the final buffer alignment: */
2337 /* 1) arch recommendation: can be overridden for debug */
2338 if (flags
& SLAB_HWCACHE_ALIGN
) {
2340 * Default alignment: as specified by the arch code. Except if
2341 * an object is really small, then squeeze multiple objects into
2344 ralign
= cache_line_size();
2345 while (size
<= ralign
/ 2)
2348 ralign
= BYTES_PER_WORD
;
2352 * Redzoning and user store require word alignment or possibly larger.
2353 * Note this will be overridden by architecture or caller mandated
2354 * alignment if either is greater than BYTES_PER_WORD.
2356 if (flags
& SLAB_STORE_USER
)
2357 ralign
= BYTES_PER_WORD
;
2359 if (flags
& SLAB_RED_ZONE
) {
2360 ralign
= REDZONE_ALIGN
;
2361 /* If redzoning, ensure that the second redzone is suitably
2362 * aligned, by adjusting the object size accordingly. */
2363 size
+= REDZONE_ALIGN
- 1;
2364 size
&= ~(REDZONE_ALIGN
- 1);
2367 /* 2) arch mandated alignment */
2368 if (ralign
< ARCH_SLAB_MINALIGN
) {
2369 ralign
= ARCH_SLAB_MINALIGN
;
2371 /* 3) caller mandated alignment */
2372 if (ralign
< align
) {
2375 /* disable debug if necessary */
2376 if (ralign
> __alignof__(unsigned long long))
2377 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
2383 if (slab_is_available())
2388 /* Get cache's description obj. */
2389 cachep
= kmem_cache_zalloc(&cache_cache
, gfp
);
2393 cachep
->nodelists
= (struct kmem_list3
**)&cachep
->array
[nr_cpu_ids
];
2394 cachep
->object_size
= size
;
2395 cachep
->align
= align
;
2399 * Both debugging options require word-alignment which is calculated
2402 if (flags
& SLAB_RED_ZONE
) {
2403 /* add space for red zone words */
2404 cachep
->obj_offset
+= sizeof(unsigned long long);
2405 size
+= 2 * sizeof(unsigned long long);
2407 if (flags
& SLAB_STORE_USER
) {
2408 /* user store requires one word storage behind the end of
2409 * the real object. But if the second red zone needs to be
2410 * aligned to 64 bits, we must allow that much space.
2412 if (flags
& SLAB_RED_ZONE
)
2413 size
+= REDZONE_ALIGN
;
2415 size
+= BYTES_PER_WORD
;
2417 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2418 if (size
>= malloc_sizes
[INDEX_L3
+ 1].cs_size
2419 && cachep
->object_size
> cache_line_size() && ALIGN(size
, align
) < PAGE_SIZE
) {
2420 cachep
->obj_offset
+= PAGE_SIZE
- ALIGN(size
, align
);
2427 * Determine if the slab management is 'on' or 'off' slab.
2428 * (bootstrapping cannot cope with offslab caches so don't do
2429 * it too early on. Always use on-slab management when
2430 * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
2432 if ((size
>= (PAGE_SIZE
>> 3)) && !slab_early_init
&&
2433 !(flags
& SLAB_NOLEAKTRACE
))
2435 * Size is large, assume best to place the slab management obj
2436 * off-slab (should allow better packing of objs).
2438 flags
|= CFLGS_OFF_SLAB
;
2440 size
= ALIGN(size
, align
);
2442 left_over
= calculate_slab_order(cachep
, size
, align
, flags
);
2446 "kmem_cache_create: couldn't create cache %s.\n", name
);
2447 kmem_cache_free(&cache_cache
, cachep
);
2451 slab_size
= ALIGN(cachep
->num
* sizeof(kmem_bufctl_t
)
2452 + sizeof(struct slab
), align
);
2455 * If the slab has been placed off-slab, and we have enough space then
2456 * move it on-slab. This is at the expense of any extra colouring.
2458 if (flags
& CFLGS_OFF_SLAB
&& left_over
>= slab_size
) {
2459 flags
&= ~CFLGS_OFF_SLAB
;
2460 left_over
-= slab_size
;
2463 if (flags
& CFLGS_OFF_SLAB
) {
2464 /* really off slab. No need for manual alignment */
2466 cachep
->num
* sizeof(kmem_bufctl_t
) + sizeof(struct slab
);
2468 #ifdef CONFIG_PAGE_POISONING
2469 /* If we're going to use the generic kernel_map_pages()
2470 * poisoning, then it's going to smash the contents of
2471 * the redzone and userword anyhow, so switch them off.
2473 if (size
% PAGE_SIZE
== 0 && flags
& SLAB_POISON
)
2474 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
2478 cachep
->colour_off
= cache_line_size();
2479 /* Offset must be a multiple of the alignment. */
2480 if (cachep
->colour_off
< align
)
2481 cachep
->colour_off
= align
;
2482 cachep
->colour
= left_over
/ cachep
->colour_off
;
2483 cachep
->slab_size
= slab_size
;
2484 cachep
->flags
= flags
;
2485 cachep
->gfpflags
= 0;
2486 if (CONFIG_ZONE_DMA_FLAG
&& (flags
& SLAB_CACHE_DMA
))
2487 cachep
->gfpflags
|= GFP_DMA
;
2488 cachep
->size
= size
;
2489 cachep
->reciprocal_buffer_size
= reciprocal_value(size
);
2491 if (flags
& CFLGS_OFF_SLAB
) {
2492 cachep
->slabp_cache
= kmem_find_general_cachep(slab_size
, 0u);
2494 * This is a possibility for one of the malloc_sizes caches.
2495 * But since we go off slab only for object size greater than
2496 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2497 * this should not happen at all.
2498 * But leave a BUG_ON for some lucky dude.
2500 BUG_ON(ZERO_OR_NULL_PTR(cachep
->slabp_cache
));
2502 cachep
->ctor
= ctor
;
2503 cachep
->name
= name
;
2505 if (setup_cpu_cache(cachep
, gfp
)) {
2506 __kmem_cache_destroy(cachep
);
2511 if (flags
& SLAB_DEBUG_OBJECTS
) {
2513 * Would deadlock through slab_destroy()->call_rcu()->
2514 * debug_object_activate()->kmem_cache_alloc().
2516 WARN_ON_ONCE(flags
& SLAB_DESTROY_BY_RCU
);
2518 slab_set_debugobj_lock_classes(cachep
);
2521 /* cache setup completed, link it into the list */
2522 list_add(&cachep
->list
, &cache_chain
);
2524 if (!cachep
&& (flags
& SLAB_PANIC
))
2525 panic("kmem_cache_create(): failed to create slab `%s'\n",
2527 if (slab_is_available()) {
2528 mutex_unlock(&cache_chain_mutex
);
2533 EXPORT_SYMBOL(kmem_cache_create
);
2536 static void check_irq_off(void)
2538 BUG_ON(!irqs_disabled());
2541 static void check_irq_on(void)
2543 BUG_ON(irqs_disabled());
2546 static void check_spinlock_acquired(struct kmem_cache
*cachep
)
2550 assert_spin_locked(&cachep
->nodelists
[numa_mem_id()]->list_lock
);
2554 static void check_spinlock_acquired_node(struct kmem_cache
*cachep
, int node
)
2558 assert_spin_locked(&cachep
->nodelists
[node
]->list_lock
);
2563 #define check_irq_off() do { } while(0)
2564 #define check_irq_on() do { } while(0)
2565 #define check_spinlock_acquired(x) do { } while(0)
2566 #define check_spinlock_acquired_node(x, y) do { } while(0)
2569 static void drain_array(struct kmem_cache
*cachep
, struct kmem_list3
*l3
,
2570 struct array_cache
*ac
,
2571 int force
, int node
);
2573 static void do_drain(void *arg
)
2575 struct kmem_cache
*cachep
= arg
;
2576 struct array_cache
*ac
;
2577 int node
= numa_mem_id();
2580 ac
= cpu_cache_get(cachep
);
2581 spin_lock(&cachep
->nodelists
[node
]->list_lock
);
2582 free_block(cachep
, ac
->entry
, ac
->avail
, node
);
2583 spin_unlock(&cachep
->nodelists
[node
]->list_lock
);
2587 static void drain_cpu_caches(struct kmem_cache
*cachep
)
2589 struct kmem_list3
*l3
;
2592 on_each_cpu(do_drain
, cachep
, 1);
2594 for_each_online_node(node
) {
2595 l3
= cachep
->nodelists
[node
];
2596 if (l3
&& l3
->alien
)
2597 drain_alien_cache(cachep
, l3
->alien
);
2600 for_each_online_node(node
) {
2601 l3
= cachep
->nodelists
[node
];
2603 drain_array(cachep
, l3
, l3
->shared
, 1, node
);
2608 * Remove slabs from the list of free slabs.
2609 * Specify the number of slabs to drain in tofree.
2611 * Returns the actual number of slabs released.
2613 static int drain_freelist(struct kmem_cache
*cache
,
2614 struct kmem_list3
*l3
, int tofree
)
2616 struct list_head
*p
;
2621 while (nr_freed
< tofree
&& !list_empty(&l3
->slabs_free
)) {
2623 spin_lock_irq(&l3
->list_lock
);
2624 p
= l3
->slabs_free
.prev
;
2625 if (p
== &l3
->slabs_free
) {
2626 spin_unlock_irq(&l3
->list_lock
);
2630 slabp
= list_entry(p
, struct slab
, list
);
2632 BUG_ON(slabp
->inuse
);
2634 list_del(&slabp
->list
);
2636 * Safe to drop the lock. The slab is no longer linked
2639 l3
->free_objects
-= cache
->num
;
2640 spin_unlock_irq(&l3
->list_lock
);
2641 slab_destroy(cache
, slabp
);
2648 /* Called with cache_chain_mutex held to protect against cpu hotplug */
2649 static int __cache_shrink(struct kmem_cache
*cachep
)
2652 struct kmem_list3
*l3
;
2654 drain_cpu_caches(cachep
);
2657 for_each_online_node(i
) {
2658 l3
= cachep
->nodelists
[i
];
2662 drain_freelist(cachep
, l3
, l3
->free_objects
);
2664 ret
+= !list_empty(&l3
->slabs_full
) ||
2665 !list_empty(&l3
->slabs_partial
);
2667 return (ret
? 1 : 0);
2671 * kmem_cache_shrink - Shrink a cache.
2672 * @cachep: The cache to shrink.
2674 * Releases as many slabs as possible for a cache.
2675 * To help debugging, a zero exit status indicates all slabs were released.
2677 int kmem_cache_shrink(struct kmem_cache
*cachep
)
2680 BUG_ON(!cachep
|| in_interrupt());
2683 mutex_lock(&cache_chain_mutex
);
2684 ret
= __cache_shrink(cachep
);
2685 mutex_unlock(&cache_chain_mutex
);
2689 EXPORT_SYMBOL(kmem_cache_shrink
);
2692 * kmem_cache_destroy - delete a cache
2693 * @cachep: the cache to destroy
2695 * Remove a &struct kmem_cache object from the slab cache.
2697 * It is expected this function will be called by a module when it is
2698 * unloaded. This will remove the cache completely, and avoid a duplicate
2699 * cache being allocated each time a module is loaded and unloaded, if the
2700 * module doesn't have persistent in-kernel storage across loads and unloads.
2702 * The cache must be empty before calling this function.
2704 * The caller must guarantee that no one will allocate memory from the cache
2705 * during the kmem_cache_destroy().
2707 void kmem_cache_destroy(struct kmem_cache
*cachep
)
2709 BUG_ON(!cachep
|| in_interrupt());
2711 /* Find the cache in the chain of caches. */
2713 mutex_lock(&cache_chain_mutex
);
2715 * the chain is never empty, cache_cache is never destroyed
2717 list_del(&cachep
->list
);
2718 if (__cache_shrink(cachep
)) {
2719 slab_error(cachep
, "Can't free all objects");
2720 list_add(&cachep
->list
, &cache_chain
);
2721 mutex_unlock(&cache_chain_mutex
);
2726 if (unlikely(cachep
->flags
& SLAB_DESTROY_BY_RCU
))
2729 __kmem_cache_destroy(cachep
);
2730 mutex_unlock(&cache_chain_mutex
);
2733 EXPORT_SYMBOL(kmem_cache_destroy
);
2736 * Get the memory for a slab management obj.
2737 * For a slab cache when the slab descriptor is off-slab, slab descriptors
2738 * always come from malloc_sizes caches. The slab descriptor cannot
2739 * come from the same cache which is getting created because,
2740 * when we are searching for an appropriate cache for these
2741 * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2742 * If we are creating a malloc_sizes cache here it would not be visible to
2743 * kmem_find_general_cachep till the initialization is complete.
2744 * Hence we cannot have slabp_cache same as the original cache.
2746 static struct slab
*alloc_slabmgmt(struct kmem_cache
*cachep
, void *objp
,
2747 int colour_off
, gfp_t local_flags
,
2752 if (OFF_SLAB(cachep
)) {
2753 /* Slab management obj is off-slab. */
2754 slabp
= kmem_cache_alloc_node(cachep
->slabp_cache
,
2755 local_flags
, nodeid
);
2757 * If the first object in the slab is leaked (it's allocated
2758 * but no one has a reference to it), we want to make sure
2759 * kmemleak does not treat the ->s_mem pointer as a reference
2760 * to the object. Otherwise we will not report the leak.
2762 kmemleak_scan_area(&slabp
->list
, sizeof(struct list_head
),
2767 slabp
= objp
+ colour_off
;
2768 colour_off
+= cachep
->slab_size
;
2771 slabp
->colouroff
= colour_off
;
2772 slabp
->s_mem
= objp
+ colour_off
;
2773 slabp
->nodeid
= nodeid
;
2778 static inline kmem_bufctl_t
*slab_bufctl(struct slab
*slabp
)
2780 return (kmem_bufctl_t
*) (slabp
+ 1);
2783 static void cache_init_objs(struct kmem_cache
*cachep
,
2788 for (i
= 0; i
< cachep
->num
; i
++) {
2789 void *objp
= index_to_obj(cachep
, slabp
, i
);
2791 /* need to poison the objs? */
2792 if (cachep
->flags
& SLAB_POISON
)
2793 poison_obj(cachep
, objp
, POISON_FREE
);
2794 if (cachep
->flags
& SLAB_STORE_USER
)
2795 *dbg_userword(cachep
, objp
) = NULL
;
2797 if (cachep
->flags
& SLAB_RED_ZONE
) {
2798 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2799 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2802 * Constructors are not allowed to allocate memory from the same
2803 * cache which they are a constructor for. Otherwise, deadlock.
2804 * They must also be threaded.
2806 if (cachep
->ctor
&& !(cachep
->flags
& SLAB_POISON
))
2807 cachep
->ctor(objp
+ obj_offset(cachep
));
2809 if (cachep
->flags
& SLAB_RED_ZONE
) {
2810 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
2811 slab_error(cachep
, "constructor overwrote the"
2812 " end of an object");
2813 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
2814 slab_error(cachep
, "constructor overwrote the"
2815 " start of an object");
2817 if ((cachep
->size
% PAGE_SIZE
) == 0 &&
2818 OFF_SLAB(cachep
) && cachep
->flags
& SLAB_POISON
)
2819 kernel_map_pages(virt_to_page(objp
),
2820 cachep
->size
/ PAGE_SIZE
, 0);
2825 slab_bufctl(slabp
)[i
] = i
+ 1;
2827 slab_bufctl(slabp
)[i
- 1] = BUFCTL_END
;
2830 static void kmem_flagcheck(struct kmem_cache
*cachep
, gfp_t flags
)
2832 if (CONFIG_ZONE_DMA_FLAG
) {
2833 if (flags
& GFP_DMA
)
2834 BUG_ON(!(cachep
->gfpflags
& GFP_DMA
));
2836 BUG_ON(cachep
->gfpflags
& GFP_DMA
);
2840 static void *slab_get_obj(struct kmem_cache
*cachep
, struct slab
*slabp
,
2843 void *objp
= index_to_obj(cachep
, slabp
, slabp
->free
);
2847 next
= slab_bufctl(slabp
)[slabp
->free
];
2849 slab_bufctl(slabp
)[slabp
->free
] = BUFCTL_FREE
;
2850 WARN_ON(slabp
->nodeid
!= nodeid
);
2857 static void slab_put_obj(struct kmem_cache
*cachep
, struct slab
*slabp
,
2858 void *objp
, int nodeid
)
2860 unsigned int objnr
= obj_to_index(cachep
, slabp
, objp
);
2863 /* Verify that the slab belongs to the intended node */
2864 WARN_ON(slabp
->nodeid
!= nodeid
);
2866 if (slab_bufctl(slabp
)[objnr
] + 1 <= SLAB_LIMIT
+ 1) {
2867 printk(KERN_ERR
"slab: double free detected in cache "
2868 "'%s', objp %p\n", cachep
->name
, objp
);
2872 slab_bufctl(slabp
)[objnr
] = slabp
->free
;
2873 slabp
->free
= objnr
;
2878 * Map pages beginning at addr to the given cache and slab. This is required
2879 * for the slab allocator to be able to lookup the cache and slab of a
2880 * virtual address for kfree, ksize, and slab debugging.
2882 static void slab_map_pages(struct kmem_cache
*cache
, struct slab
*slab
,
2888 page
= virt_to_page(addr
);
2891 if (likely(!PageCompound(page
)))
2892 nr_pages
<<= cache
->gfporder
;
2895 page
->slab_cache
= cache
;
2896 page
->slab_page
= slab
;
2898 } while (--nr_pages
);
2902 * Grow (by 1) the number of slabs within a cache. This is called by
2903 * kmem_cache_alloc() when there are no active objs left in a cache.
2905 static int cache_grow(struct kmem_cache
*cachep
,
2906 gfp_t flags
, int nodeid
, void *objp
)
2911 struct kmem_list3
*l3
;
2914 * Be lazy and only check for valid flags here, keeping it out of the
2915 * critical path in kmem_cache_alloc().
2917 BUG_ON(flags
& GFP_SLAB_BUG_MASK
);
2918 local_flags
= flags
& (GFP_CONSTRAINT_MASK
|GFP_RECLAIM_MASK
);
2920 /* Take the l3 list lock to change the colour_next on this node */
2922 l3
= cachep
->nodelists
[nodeid
];
2923 spin_lock(&l3
->list_lock
);
2925 /* Get colour for the slab, and cal the next value. */
2926 offset
= l3
->colour_next
;
2928 if (l3
->colour_next
>= cachep
->colour
)
2929 l3
->colour_next
= 0;
2930 spin_unlock(&l3
->list_lock
);
2932 offset
*= cachep
->colour_off
;
2934 if (local_flags
& __GFP_WAIT
)
2938 * The test for missing atomic flag is performed here, rather than
2939 * the more obvious place, simply to reduce the critical path length
2940 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2941 * will eventually be caught here (where it matters).
2943 kmem_flagcheck(cachep
, flags
);
2946 * Get mem for the objs. Attempt to allocate a physical page from
2950 objp
= kmem_getpages(cachep
, local_flags
, nodeid
);
2954 /* Get slab management. */
2955 slabp
= alloc_slabmgmt(cachep
, objp
, offset
,
2956 local_flags
& ~GFP_CONSTRAINT_MASK
, nodeid
);
2960 slab_map_pages(cachep
, slabp
, objp
);
2962 cache_init_objs(cachep
, slabp
);
2964 if (local_flags
& __GFP_WAIT
)
2965 local_irq_disable();
2967 spin_lock(&l3
->list_lock
);
2969 /* Make slab active. */
2970 list_add_tail(&slabp
->list
, &(l3
->slabs_free
));
2971 STATS_INC_GROWN(cachep
);
2972 l3
->free_objects
+= cachep
->num
;
2973 spin_unlock(&l3
->list_lock
);
2976 kmem_freepages(cachep
, objp
);
2978 if (local_flags
& __GFP_WAIT
)
2979 local_irq_disable();
2986 * Perform extra freeing checks:
2987 * - detect bad pointers.
2988 * - POISON/RED_ZONE checking
2990 static void kfree_debugcheck(const void *objp
)
2992 if (!virt_addr_valid(objp
)) {
2993 printk(KERN_ERR
"kfree_debugcheck: out of range ptr %lxh.\n",
2994 (unsigned long)objp
);
2999 static inline void verify_redzone_free(struct kmem_cache
*cache
, void *obj
)
3001 unsigned long long redzone1
, redzone2
;
3003 redzone1
= *dbg_redzone1(cache
, obj
);
3004 redzone2
= *dbg_redzone2(cache
, obj
);
3009 if (redzone1
== RED_ACTIVE
&& redzone2
== RED_ACTIVE
)
3012 if (redzone1
== RED_INACTIVE
&& redzone2
== RED_INACTIVE
)
3013 slab_error(cache
, "double free detected");
3015 slab_error(cache
, "memory outside object was overwritten");
3017 printk(KERN_ERR
"%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
3018 obj
, redzone1
, redzone2
);
3021 static void *cache_free_debugcheck(struct kmem_cache
*cachep
, void *objp
,
3028 BUG_ON(virt_to_cache(objp
) != cachep
);
3030 objp
-= obj_offset(cachep
);
3031 kfree_debugcheck(objp
);
3032 page
= virt_to_head_page(objp
);
3034 slabp
= page
->slab_page
;
3036 if (cachep
->flags
& SLAB_RED_ZONE
) {
3037 verify_redzone_free(cachep
, objp
);
3038 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
3039 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
3041 if (cachep
->flags
& SLAB_STORE_USER
)
3042 *dbg_userword(cachep
, objp
) = caller
;
3044 objnr
= obj_to_index(cachep
, slabp
, objp
);
3046 BUG_ON(objnr
>= cachep
->num
);
3047 BUG_ON(objp
!= index_to_obj(cachep
, slabp
, objnr
));
3049 #ifdef CONFIG_DEBUG_SLAB_LEAK
3050 slab_bufctl(slabp
)[objnr
] = BUFCTL_FREE
;
3052 if (cachep
->flags
& SLAB_POISON
) {
3053 #ifdef CONFIG_DEBUG_PAGEALLOC
3054 if ((cachep
->size
% PAGE_SIZE
)==0 && OFF_SLAB(cachep
)) {
3055 store_stackinfo(cachep
, objp
, (unsigned long)caller
);
3056 kernel_map_pages(virt_to_page(objp
),
3057 cachep
->size
/ PAGE_SIZE
, 0);
3059 poison_obj(cachep
, objp
, POISON_FREE
);
3062 poison_obj(cachep
, objp
, POISON_FREE
);
3068 static void check_slabp(struct kmem_cache
*cachep
, struct slab
*slabp
)
3073 /* Check slab's freelist to see if this obj is there. */
3074 for (i
= slabp
->free
; i
!= BUFCTL_END
; i
= slab_bufctl(slabp
)[i
]) {
3076 if (entries
> cachep
->num
|| i
>= cachep
->num
)
3079 if (entries
!= cachep
->num
- slabp
->inuse
) {
3081 printk(KERN_ERR
"slab: Internal list corruption detected in "
3082 "cache '%s'(%d), slabp %p(%d). Tainted(%s). Hexdump:\n",
3083 cachep
->name
, cachep
->num
, slabp
, slabp
->inuse
,
3085 print_hex_dump(KERN_ERR
, "", DUMP_PREFIX_OFFSET
, 16, 1, slabp
,
3086 sizeof(*slabp
) + cachep
->num
* sizeof(kmem_bufctl_t
),
3092 #define kfree_debugcheck(x) do { } while(0)
3093 #define cache_free_debugcheck(x,objp,z) (objp)
3094 #define check_slabp(x,y) do { } while(0)
3097 static void *cache_alloc_refill(struct kmem_cache
*cachep
, gfp_t flags
)
3100 struct kmem_list3
*l3
;
3101 struct array_cache
*ac
;
3106 node
= numa_mem_id();
3107 ac
= cpu_cache_get(cachep
);
3108 batchcount
= ac
->batchcount
;
3109 if (!ac
->touched
&& batchcount
> BATCHREFILL_LIMIT
) {
3111 * If there was little recent activity on this cache, then
3112 * perform only a partial refill. Otherwise we could generate
3115 batchcount
= BATCHREFILL_LIMIT
;
3117 l3
= cachep
->nodelists
[node
];
3119 BUG_ON(ac
->avail
> 0 || !l3
);
3120 spin_lock(&l3
->list_lock
);
3122 /* See if we can refill from the shared array */
3123 if (l3
->shared
&& transfer_objects(ac
, l3
->shared
, batchcount
)) {
3124 l3
->shared
->touched
= 1;
3128 while (batchcount
> 0) {
3129 struct list_head
*entry
;
3131 /* Get slab alloc is to come from. */
3132 entry
= l3
->slabs_partial
.next
;
3133 if (entry
== &l3
->slabs_partial
) {
3134 l3
->free_touched
= 1;
3135 entry
= l3
->slabs_free
.next
;
3136 if (entry
== &l3
->slabs_free
)
3140 slabp
= list_entry(entry
, struct slab
, list
);
3141 check_slabp(cachep
, slabp
);
3142 check_spinlock_acquired(cachep
);
3145 * The slab was either on partial or free list so
3146 * there must be at least one object available for
3149 BUG_ON(slabp
->inuse
>= cachep
->num
);
3151 while (slabp
->inuse
< cachep
->num
&& batchcount
--) {
3152 STATS_INC_ALLOCED(cachep
);
3153 STATS_INC_ACTIVE(cachep
);
3154 STATS_SET_HIGH(cachep
);
3156 ac
->entry
[ac
->avail
++] = slab_get_obj(cachep
, slabp
,
3159 check_slabp(cachep
, slabp
);
3161 /* move slabp to correct slabp list: */
3162 list_del(&slabp
->list
);
3163 if (slabp
->free
== BUFCTL_END
)
3164 list_add(&slabp
->list
, &l3
->slabs_full
);
3166 list_add(&slabp
->list
, &l3
->slabs_partial
);
3170 l3
->free_objects
-= ac
->avail
;
3172 spin_unlock(&l3
->list_lock
);
3174 if (unlikely(!ac
->avail
)) {
3176 x
= cache_grow(cachep
, flags
| GFP_THISNODE
, node
, NULL
);
3178 /* cache_grow can reenable interrupts, then ac could change. */
3179 ac
= cpu_cache_get(cachep
);
3180 if (!x
&& ac
->avail
== 0) /* no objects in sight? abort */
3183 if (!ac
->avail
) /* objects refilled by interrupt? */
3187 return ac
->entry
[--ac
->avail
];
3190 static inline void cache_alloc_debugcheck_before(struct kmem_cache
*cachep
,
3193 might_sleep_if(flags
& __GFP_WAIT
);
3195 kmem_flagcheck(cachep
, flags
);
3200 static void *cache_alloc_debugcheck_after(struct kmem_cache
*cachep
,
3201 gfp_t flags
, void *objp
, void *caller
)
3205 if (cachep
->flags
& SLAB_POISON
) {
3206 #ifdef CONFIG_DEBUG_PAGEALLOC
3207 if ((cachep
->size
% PAGE_SIZE
) == 0 && OFF_SLAB(cachep
))
3208 kernel_map_pages(virt_to_page(objp
),
3209 cachep
->size
/ PAGE_SIZE
, 1);
3211 check_poison_obj(cachep
, objp
);
3213 check_poison_obj(cachep
, objp
);
3215 poison_obj(cachep
, objp
, POISON_INUSE
);
3217 if (cachep
->flags
& SLAB_STORE_USER
)
3218 *dbg_userword(cachep
, objp
) = caller
;
3220 if (cachep
->flags
& SLAB_RED_ZONE
) {
3221 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
||
3222 *dbg_redzone2(cachep
, objp
) != RED_INACTIVE
) {
3223 slab_error(cachep
, "double free, or memory outside"
3224 " object was overwritten");
3226 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3227 objp
, *dbg_redzone1(cachep
, objp
),
3228 *dbg_redzone2(cachep
, objp
));
3230 *dbg_redzone1(cachep
, objp
) = RED_ACTIVE
;
3231 *dbg_redzone2(cachep
, objp
) = RED_ACTIVE
;
3233 #ifdef CONFIG_DEBUG_SLAB_LEAK
3238 slabp
= virt_to_head_page(objp
)->slab_page
;
3239 objnr
= (unsigned)(objp
- slabp
->s_mem
) / cachep
->size
;
3240 slab_bufctl(slabp
)[objnr
] = BUFCTL_ACTIVE
;
3243 objp
+= obj_offset(cachep
);
3244 if (cachep
->ctor
&& cachep
->flags
& SLAB_POISON
)
3246 if (ARCH_SLAB_MINALIGN
&&
3247 ((unsigned long)objp
& (ARCH_SLAB_MINALIGN
-1))) {
3248 printk(KERN_ERR
"0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3249 objp
, (int)ARCH_SLAB_MINALIGN
);
3254 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3257 static bool slab_should_failslab(struct kmem_cache
*cachep
, gfp_t flags
)
3259 if (cachep
== &cache_cache
)
3262 return should_failslab(cachep
->object_size
, flags
, cachep
->flags
);
3265 static inline void *____cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3268 struct array_cache
*ac
;
3272 ac
= cpu_cache_get(cachep
);
3273 if (likely(ac
->avail
)) {
3274 STATS_INC_ALLOCHIT(cachep
);
3276 objp
= ac
->entry
[--ac
->avail
];
3278 STATS_INC_ALLOCMISS(cachep
);
3279 objp
= cache_alloc_refill(cachep
, flags
);
3281 * the 'ac' may be updated by cache_alloc_refill(),
3282 * and kmemleak_erase() requires its correct value.
3284 ac
= cpu_cache_get(cachep
);
3287 * To avoid a false negative, if an object that is in one of the
3288 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3289 * treat the array pointers as a reference to the object.
3292 kmemleak_erase(&ac
->entry
[ac
->avail
]);
3298 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3300 * If we are in_interrupt, then process context, including cpusets and
3301 * mempolicy, may not apply and should not be used for allocation policy.
3303 static void *alternate_node_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3305 int nid_alloc
, nid_here
;
3307 if (in_interrupt() || (flags
& __GFP_THISNODE
))
3309 nid_alloc
= nid_here
= numa_mem_id();
3310 if (cpuset_do_slab_mem_spread() && (cachep
->flags
& SLAB_MEM_SPREAD
))
3311 nid_alloc
= cpuset_slab_spread_node();
3312 else if (current
->mempolicy
)
3313 nid_alloc
= slab_node();
3314 if (nid_alloc
!= nid_here
)
3315 return ____cache_alloc_node(cachep
, flags
, nid_alloc
);
3320 * Fallback function if there was no memory available and no objects on a
3321 * certain node and fall back is permitted. First we scan all the
3322 * available nodelists for available objects. If that fails then we
3323 * perform an allocation without specifying a node. This allows the page
3324 * allocator to do its reclaim / fallback magic. We then insert the
3325 * slab into the proper nodelist and then allocate from it.
3327 static void *fallback_alloc(struct kmem_cache
*cache
, gfp_t flags
)
3329 struct zonelist
*zonelist
;
3333 enum zone_type high_zoneidx
= gfp_zone(flags
);
3336 unsigned int cpuset_mems_cookie
;
3338 if (flags
& __GFP_THISNODE
)
3341 local_flags
= flags
& (GFP_CONSTRAINT_MASK
|GFP_RECLAIM_MASK
);
3344 cpuset_mems_cookie
= get_mems_allowed();
3345 zonelist
= node_zonelist(slab_node(), flags
);
3349 * Look through allowed nodes for objects available
3350 * from existing per node queues.
3352 for_each_zone_zonelist(zone
, z
, zonelist
, high_zoneidx
) {
3353 nid
= zone_to_nid(zone
);
3355 if (cpuset_zone_allowed_hardwall(zone
, flags
) &&
3356 cache
->nodelists
[nid
] &&
3357 cache
->nodelists
[nid
]->free_objects
) {
3358 obj
= ____cache_alloc_node(cache
,
3359 flags
| GFP_THISNODE
, nid
);
3367 * This allocation will be performed within the constraints
3368 * of the current cpuset / memory policy requirements.
3369 * We may trigger various forms of reclaim on the allowed
3370 * set and go into memory reserves if necessary.
3372 if (local_flags
& __GFP_WAIT
)
3374 kmem_flagcheck(cache
, flags
);
3375 obj
= kmem_getpages(cache
, local_flags
, numa_mem_id());
3376 if (local_flags
& __GFP_WAIT
)
3377 local_irq_disable();
3380 * Insert into the appropriate per node queues
3382 nid
= page_to_nid(virt_to_page(obj
));
3383 if (cache_grow(cache
, flags
, nid
, obj
)) {
3384 obj
= ____cache_alloc_node(cache
,
3385 flags
| GFP_THISNODE
, nid
);
3388 * Another processor may allocate the
3389 * objects in the slab since we are
3390 * not holding any locks.
3394 /* cache_grow already freed obj */
3400 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !obj
))
3406 * A interface to enable slab creation on nodeid
3408 static void *____cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
,
3411 struct list_head
*entry
;
3413 struct kmem_list3
*l3
;
3417 l3
= cachep
->nodelists
[nodeid
];
3422 spin_lock(&l3
->list_lock
);
3423 entry
= l3
->slabs_partial
.next
;
3424 if (entry
== &l3
->slabs_partial
) {
3425 l3
->free_touched
= 1;
3426 entry
= l3
->slabs_free
.next
;
3427 if (entry
== &l3
->slabs_free
)
3431 slabp
= list_entry(entry
, struct slab
, list
);
3432 check_spinlock_acquired_node(cachep
, nodeid
);
3433 check_slabp(cachep
, slabp
);
3435 STATS_INC_NODEALLOCS(cachep
);
3436 STATS_INC_ACTIVE(cachep
);
3437 STATS_SET_HIGH(cachep
);
3439 BUG_ON(slabp
->inuse
== cachep
->num
);
3441 obj
= slab_get_obj(cachep
, slabp
, nodeid
);
3442 check_slabp(cachep
, slabp
);
3444 /* move slabp to correct slabp list: */
3445 list_del(&slabp
->list
);
3447 if (slabp
->free
== BUFCTL_END
)
3448 list_add(&slabp
->list
, &l3
->slabs_full
);
3450 list_add(&slabp
->list
, &l3
->slabs_partial
);
3452 spin_unlock(&l3
->list_lock
);
3456 spin_unlock(&l3
->list_lock
);
3457 x
= cache_grow(cachep
, flags
| GFP_THISNODE
, nodeid
, NULL
);
3461 return fallback_alloc(cachep
, flags
);
3468 * kmem_cache_alloc_node - Allocate an object on the specified node
3469 * @cachep: The cache to allocate from.
3470 * @flags: See kmalloc().
3471 * @nodeid: node number of the target node.
3472 * @caller: return address of caller, used for debug information
3474 * Identical to kmem_cache_alloc but it will allocate memory on the given
3475 * node, which can improve the performance for cpu bound structures.
3477 * Fallback to other node is possible if __GFP_THISNODE is not set.
3479 static __always_inline
void *
3480 __cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
,
3483 unsigned long save_flags
;
3485 int slab_node
= numa_mem_id();
3487 flags
&= gfp_allowed_mask
;
3489 lockdep_trace_alloc(flags
);
3491 if (slab_should_failslab(cachep
, flags
))
3494 cache_alloc_debugcheck_before(cachep
, flags
);
3495 local_irq_save(save_flags
);
3497 if (nodeid
== NUMA_NO_NODE
)
3500 if (unlikely(!cachep
->nodelists
[nodeid
])) {
3501 /* Node not bootstrapped yet */
3502 ptr
= fallback_alloc(cachep
, flags
);
3506 if (nodeid
== slab_node
) {
3508 * Use the locally cached objects if possible.
3509 * However ____cache_alloc does not allow fallback
3510 * to other nodes. It may fail while we still have
3511 * objects on other nodes available.
3513 ptr
= ____cache_alloc(cachep
, flags
);
3517 /* ___cache_alloc_node can fall back to other nodes */
3518 ptr
= ____cache_alloc_node(cachep
, flags
, nodeid
);
3520 local_irq_restore(save_flags
);
3521 ptr
= cache_alloc_debugcheck_after(cachep
, flags
, ptr
, caller
);
3522 kmemleak_alloc_recursive(ptr
, cachep
->object_size
, 1, cachep
->flags
,
3526 kmemcheck_slab_alloc(cachep
, flags
, ptr
, cachep
->object_size
);
3528 if (unlikely((flags
& __GFP_ZERO
) && ptr
))
3529 memset(ptr
, 0, cachep
->object_size
);
3534 static __always_inline
void *
3535 __do_cache_alloc(struct kmem_cache
*cache
, gfp_t flags
)
3539 if (unlikely(current
->flags
& (PF_SPREAD_SLAB
| PF_MEMPOLICY
))) {
3540 objp
= alternate_node_alloc(cache
, flags
);
3544 objp
= ____cache_alloc(cache
, flags
);
3547 * We may just have run out of memory on the local node.
3548 * ____cache_alloc_node() knows how to locate memory on other nodes
3551 objp
= ____cache_alloc_node(cache
, flags
, numa_mem_id());
3558 static __always_inline
void *
3559 __do_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3561 return ____cache_alloc(cachep
, flags
);
3564 #endif /* CONFIG_NUMA */
3566 static __always_inline
void *
3567 __cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
, void *caller
)
3569 unsigned long save_flags
;
3572 flags
&= gfp_allowed_mask
;
3574 lockdep_trace_alloc(flags
);
3576 if (slab_should_failslab(cachep
, flags
))
3579 cache_alloc_debugcheck_before(cachep
, flags
);
3580 local_irq_save(save_flags
);
3581 objp
= __do_cache_alloc(cachep
, flags
);
3582 local_irq_restore(save_flags
);
3583 objp
= cache_alloc_debugcheck_after(cachep
, flags
, objp
, caller
);
3584 kmemleak_alloc_recursive(objp
, cachep
->object_size
, 1, cachep
->flags
,
3589 kmemcheck_slab_alloc(cachep
, flags
, objp
, cachep
->object_size
);
3591 if (unlikely((flags
& __GFP_ZERO
) && objp
))
3592 memset(objp
, 0, cachep
->object_size
);
3598 * Caller needs to acquire correct kmem_list's list_lock
3600 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int nr_objects
,
3604 struct kmem_list3
*l3
;
3606 for (i
= 0; i
< nr_objects
; i
++) {
3607 void *objp
= objpp
[i
];
3610 slabp
= virt_to_slab(objp
);
3611 l3
= cachep
->nodelists
[node
];
3612 list_del(&slabp
->list
);
3613 check_spinlock_acquired_node(cachep
, node
);
3614 check_slabp(cachep
, slabp
);
3615 slab_put_obj(cachep
, slabp
, objp
, node
);
3616 STATS_DEC_ACTIVE(cachep
);
3618 check_slabp(cachep
, slabp
);
3620 /* fixup slab chains */
3621 if (slabp
->inuse
== 0) {
3622 if (l3
->free_objects
> l3
->free_limit
) {
3623 l3
->free_objects
-= cachep
->num
;
3624 /* No need to drop any previously held
3625 * lock here, even if we have a off-slab slab
3626 * descriptor it is guaranteed to come from
3627 * a different cache, refer to comments before
3630 slab_destroy(cachep
, slabp
);
3632 list_add(&slabp
->list
, &l3
->slabs_free
);
3635 /* Unconditionally move a slab to the end of the
3636 * partial list on free - maximum time for the
3637 * other objects to be freed, too.
3639 list_add_tail(&slabp
->list
, &l3
->slabs_partial
);
3644 static void cache_flusharray(struct kmem_cache
*cachep
, struct array_cache
*ac
)
3647 struct kmem_list3
*l3
;
3648 int node
= numa_mem_id();
3650 batchcount
= ac
->batchcount
;
3652 BUG_ON(!batchcount
|| batchcount
> ac
->avail
);
3655 l3
= cachep
->nodelists
[node
];
3656 spin_lock(&l3
->list_lock
);
3658 struct array_cache
*shared_array
= l3
->shared
;
3659 int max
= shared_array
->limit
- shared_array
->avail
;
3661 if (batchcount
> max
)
3663 memcpy(&(shared_array
->entry
[shared_array
->avail
]),
3664 ac
->entry
, sizeof(void *) * batchcount
);
3665 shared_array
->avail
+= batchcount
;
3670 free_block(cachep
, ac
->entry
, batchcount
, node
);
3675 struct list_head
*p
;
3677 p
= l3
->slabs_free
.next
;
3678 while (p
!= &(l3
->slabs_free
)) {
3681 slabp
= list_entry(p
, struct slab
, list
);
3682 BUG_ON(slabp
->inuse
);
3687 STATS_SET_FREEABLE(cachep
, i
);
3690 spin_unlock(&l3
->list_lock
);
3691 ac
->avail
-= batchcount
;
3692 memmove(ac
->entry
, &(ac
->entry
[batchcount
]), sizeof(void *)*ac
->avail
);
3696 * Release an obj back to its cache. If the obj has a constructed state, it must
3697 * be in this state _before_ it is released. Called with disabled ints.
3699 static inline void __cache_free(struct kmem_cache
*cachep
, void *objp
,
3702 struct array_cache
*ac
= cpu_cache_get(cachep
);
3705 kmemleak_free_recursive(objp
, cachep
->flags
);
3706 objp
= cache_free_debugcheck(cachep
, objp
, caller
);
3708 kmemcheck_slab_free(cachep
, objp
, cachep
->object_size
);
3711 * Skip calling cache_free_alien() when the platform is not numa.
3712 * This will avoid cache misses that happen while accessing slabp (which
3713 * is per page memory reference) to get nodeid. Instead use a global
3714 * variable to skip the call, which is mostly likely to be present in
3717 if (nr_online_nodes
> 1 && cache_free_alien(cachep
, objp
))
3720 if (likely(ac
->avail
< ac
->limit
)) {
3721 STATS_INC_FREEHIT(cachep
);
3723 STATS_INC_FREEMISS(cachep
);
3724 cache_flusharray(cachep
, ac
);
3727 ac
->entry
[ac
->avail
++] = objp
;
3731 * kmem_cache_alloc - Allocate an object
3732 * @cachep: The cache to allocate from.
3733 * @flags: See kmalloc().
3735 * Allocate an object from this cache. The flags are only relevant
3736 * if the cache has no available objects.
3738 void *kmem_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3740 void *ret
= __cache_alloc(cachep
, flags
, __builtin_return_address(0));
3742 trace_kmem_cache_alloc(_RET_IP_
, ret
,
3743 cachep
->object_size
, cachep
->size
, flags
);
3747 EXPORT_SYMBOL(kmem_cache_alloc
);
3749 #ifdef CONFIG_TRACING
3751 kmem_cache_alloc_trace(size_t size
, struct kmem_cache
*cachep
, gfp_t flags
)
3755 ret
= __cache_alloc(cachep
, flags
, __builtin_return_address(0));
3757 trace_kmalloc(_RET_IP_
, ret
,
3758 size
, slab_buffer_size(cachep
), flags
);
3761 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
3765 void *kmem_cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
3767 void *ret
= __cache_alloc_node(cachep
, flags
, nodeid
,
3768 __builtin_return_address(0));
3770 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
3771 cachep
->object_size
, cachep
->size
,
3776 EXPORT_SYMBOL(kmem_cache_alloc_node
);
3778 #ifdef CONFIG_TRACING
3779 void *kmem_cache_alloc_node_trace(size_t size
,
3780 struct kmem_cache
*cachep
,
3786 ret
= __cache_alloc_node(cachep
, flags
, nodeid
,
3787 __builtin_return_address(0));
3788 trace_kmalloc_node(_RET_IP_
, ret
,
3789 size
, slab_buffer_size(cachep
),
3793 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
3796 static __always_inline
void *
3797 __do_kmalloc_node(size_t size
, gfp_t flags
, int node
, void *caller
)
3799 struct kmem_cache
*cachep
;
3801 cachep
= kmem_find_general_cachep(size
, flags
);
3802 if (unlikely(ZERO_OR_NULL_PTR(cachep
)))
3804 return kmem_cache_alloc_node_trace(size
, cachep
, flags
, node
);
3807 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3808 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3810 return __do_kmalloc_node(size
, flags
, node
,
3811 __builtin_return_address(0));
3813 EXPORT_SYMBOL(__kmalloc_node
);
3815 void *__kmalloc_node_track_caller(size_t size
, gfp_t flags
,
3816 int node
, unsigned long caller
)
3818 return __do_kmalloc_node(size
, flags
, node
, (void *)caller
);
3820 EXPORT_SYMBOL(__kmalloc_node_track_caller
);
3822 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3824 return __do_kmalloc_node(size
, flags
, node
, NULL
);
3826 EXPORT_SYMBOL(__kmalloc_node
);
3827 #endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */
3828 #endif /* CONFIG_NUMA */
3831 * __do_kmalloc - allocate memory
3832 * @size: how many bytes of memory are required.
3833 * @flags: the type of memory to allocate (see kmalloc).
3834 * @caller: function caller for debug tracking of the caller
3836 static __always_inline
void *__do_kmalloc(size_t size
, gfp_t flags
,
3839 struct kmem_cache
*cachep
;
3842 /* If you want to save a few bytes .text space: replace
3844 * Then kmalloc uses the uninlined functions instead of the inline
3847 cachep
= __find_general_cachep(size
, flags
);
3848 if (unlikely(ZERO_OR_NULL_PTR(cachep
)))
3850 ret
= __cache_alloc(cachep
, flags
, caller
);
3852 trace_kmalloc((unsigned long) caller
, ret
,
3853 size
, cachep
->size
, flags
);
3859 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3860 void *__kmalloc(size_t size
, gfp_t flags
)
3862 return __do_kmalloc(size
, flags
, __builtin_return_address(0));
3864 EXPORT_SYMBOL(__kmalloc
);
3866 void *__kmalloc_track_caller(size_t size
, gfp_t flags
, unsigned long caller
)
3868 return __do_kmalloc(size
, flags
, (void *)caller
);
3870 EXPORT_SYMBOL(__kmalloc_track_caller
);
3873 void *__kmalloc(size_t size
, gfp_t flags
)
3875 return __do_kmalloc(size
, flags
, NULL
);
3877 EXPORT_SYMBOL(__kmalloc
);
3881 * kmem_cache_free - Deallocate an object
3882 * @cachep: The cache the allocation was from.
3883 * @objp: The previously allocated object.
3885 * Free an object which was previously allocated from this
3888 void kmem_cache_free(struct kmem_cache
*cachep
, void *objp
)
3890 unsigned long flags
;
3892 local_irq_save(flags
);
3893 debug_check_no_locks_freed(objp
, cachep
->size
);
3894 if (!(cachep
->flags
& SLAB_DEBUG_OBJECTS
))
3895 debug_check_no_obj_freed(objp
, cachep
->object_size
);
3896 __cache_free(cachep
, objp
, __builtin_return_address(0));
3897 local_irq_restore(flags
);
3899 trace_kmem_cache_free(_RET_IP_
, objp
);
3901 EXPORT_SYMBOL(kmem_cache_free
);
3904 * kfree - free previously allocated memory
3905 * @objp: pointer returned by kmalloc.
3907 * If @objp is NULL, no operation is performed.
3909 * Don't free memory not originally allocated by kmalloc()
3910 * or you will run into trouble.
3912 void kfree(const void *objp
)
3914 struct kmem_cache
*c
;
3915 unsigned long flags
;
3917 trace_kfree(_RET_IP_
, objp
);
3919 if (unlikely(ZERO_OR_NULL_PTR(objp
)))
3921 local_irq_save(flags
);
3922 kfree_debugcheck(objp
);
3923 c
= virt_to_cache(objp
);
3924 debug_check_no_locks_freed(objp
, c
->object_size
);
3926 debug_check_no_obj_freed(objp
, c
->object_size
);
3927 __cache_free(c
, (void *)objp
, __builtin_return_address(0));
3928 local_irq_restore(flags
);
3930 EXPORT_SYMBOL(kfree
);
3932 unsigned int kmem_cache_size(struct kmem_cache
*cachep
)
3934 return cachep
->object_size
;
3936 EXPORT_SYMBOL(kmem_cache_size
);
3939 * This initializes kmem_list3 or resizes various caches for all nodes.
3941 static int alloc_kmemlist(struct kmem_cache
*cachep
, gfp_t gfp
)
3944 struct kmem_list3
*l3
;
3945 struct array_cache
*new_shared
;
3946 struct array_cache
**new_alien
= NULL
;
3948 for_each_online_node(node
) {
3950 if (use_alien_caches
) {
3951 new_alien
= alloc_alien_cache(node
, cachep
->limit
, gfp
);
3957 if (cachep
->shared
) {
3958 new_shared
= alloc_arraycache(node
,
3959 cachep
->shared
*cachep
->batchcount
,
3962 free_alien_cache(new_alien
);
3967 l3
= cachep
->nodelists
[node
];
3969 struct array_cache
*shared
= l3
->shared
;
3971 spin_lock_irq(&l3
->list_lock
);
3974 free_block(cachep
, shared
->entry
,
3975 shared
->avail
, node
);
3977 l3
->shared
= new_shared
;
3979 l3
->alien
= new_alien
;
3982 l3
->free_limit
= (1 + nr_cpus_node(node
)) *
3983 cachep
->batchcount
+ cachep
->num
;
3984 spin_unlock_irq(&l3
->list_lock
);
3986 free_alien_cache(new_alien
);
3989 l3
= kmalloc_node(sizeof(struct kmem_list3
), gfp
, node
);
3991 free_alien_cache(new_alien
);
3996 kmem_list3_init(l3
);
3997 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
+
3998 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
3999 l3
->shared
= new_shared
;
4000 l3
->alien
= new_alien
;
4001 l3
->free_limit
= (1 + nr_cpus_node(node
)) *
4002 cachep
->batchcount
+ cachep
->num
;
4003 cachep
->nodelists
[node
] = l3
;
4008 if (!cachep
->list
.next
) {
4009 /* Cache is not active yet. Roll back what we did */
4012 if (cachep
->nodelists
[node
]) {
4013 l3
= cachep
->nodelists
[node
];
4016 free_alien_cache(l3
->alien
);
4018 cachep
->nodelists
[node
] = NULL
;
4026 struct ccupdate_struct
{
4027 struct kmem_cache
*cachep
;
4028 struct array_cache
*new[0];
4031 static void do_ccupdate_local(void *info
)
4033 struct ccupdate_struct
*new = info
;
4034 struct array_cache
*old
;
4037 old
= cpu_cache_get(new->cachep
);
4039 new->cachep
->array
[smp_processor_id()] = new->new[smp_processor_id()];
4040 new->new[smp_processor_id()] = old
;
4043 /* Always called with the cache_chain_mutex held */
4044 static int do_tune_cpucache(struct kmem_cache
*cachep
, int limit
,
4045 int batchcount
, int shared
, gfp_t gfp
)
4047 struct ccupdate_struct
*new;
4050 new = kzalloc(sizeof(*new) + nr_cpu_ids
* sizeof(struct array_cache
*),
4055 for_each_online_cpu(i
) {
4056 new->new[i
] = alloc_arraycache(cpu_to_mem(i
), limit
,
4059 for (i
--; i
>= 0; i
--)
4065 new->cachep
= cachep
;
4067 on_each_cpu(do_ccupdate_local
, (void *)new, 1);
4070 cachep
->batchcount
= batchcount
;
4071 cachep
->limit
= limit
;
4072 cachep
->shared
= shared
;
4074 for_each_online_cpu(i
) {
4075 struct array_cache
*ccold
= new->new[i
];
4078 spin_lock_irq(&cachep
->nodelists
[cpu_to_mem(i
)]->list_lock
);
4079 free_block(cachep
, ccold
->entry
, ccold
->avail
, cpu_to_mem(i
));
4080 spin_unlock_irq(&cachep
->nodelists
[cpu_to_mem(i
)]->list_lock
);
4084 return alloc_kmemlist(cachep
, gfp
);
4087 /* Called with cache_chain_mutex held always */
4088 static int enable_cpucache(struct kmem_cache
*cachep
, gfp_t gfp
)
4094 * The head array serves three purposes:
4095 * - create a LIFO ordering, i.e. return objects that are cache-warm
4096 * - reduce the number of spinlock operations.
4097 * - reduce the number of linked list operations on the slab and
4098 * bufctl chains: array operations are cheaper.
4099 * The numbers are guessed, we should auto-tune as described by
4102 if (cachep
->size
> 131072)
4104 else if (cachep
->size
> PAGE_SIZE
)
4106 else if (cachep
->size
> 1024)
4108 else if (cachep
->size
> 256)
4114 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
4115 * allocation behaviour: Most allocs on one cpu, most free operations
4116 * on another cpu. For these cases, an efficient object passing between
4117 * cpus is necessary. This is provided by a shared array. The array
4118 * replaces Bonwick's magazine layer.
4119 * On uniprocessor, it's functionally equivalent (but less efficient)
4120 * to a larger limit. Thus disabled by default.
4123 if (cachep
->size
<= PAGE_SIZE
&& num_possible_cpus() > 1)
4128 * With debugging enabled, large batchcount lead to excessively long
4129 * periods with disabled local interrupts. Limit the batchcount
4134 err
= do_tune_cpucache(cachep
, limit
, (limit
+ 1) / 2, shared
, gfp
);
4136 printk(KERN_ERR
"enable_cpucache failed for %s, error %d.\n",
4137 cachep
->name
, -err
);
4142 * Drain an array if it contains any elements taking the l3 lock only if
4143 * necessary. Note that the l3 listlock also protects the array_cache
4144 * if drain_array() is used on the shared array.
4146 static void drain_array(struct kmem_cache
*cachep
, struct kmem_list3
*l3
,
4147 struct array_cache
*ac
, int force
, int node
)
4151 if (!ac
|| !ac
->avail
)
4153 if (ac
->touched
&& !force
) {
4156 spin_lock_irq(&l3
->list_lock
);
4158 tofree
= force
? ac
->avail
: (ac
->limit
+ 4) / 5;
4159 if (tofree
> ac
->avail
)
4160 tofree
= (ac
->avail
+ 1) / 2;
4161 free_block(cachep
, ac
->entry
, tofree
, node
);
4162 ac
->avail
-= tofree
;
4163 memmove(ac
->entry
, &(ac
->entry
[tofree
]),
4164 sizeof(void *) * ac
->avail
);
4166 spin_unlock_irq(&l3
->list_lock
);
4171 * cache_reap - Reclaim memory from caches.
4172 * @w: work descriptor
4174 * Called from workqueue/eventd every few seconds.
4176 * - clear the per-cpu caches for this CPU.
4177 * - return freeable pages to the main free memory pool.
4179 * If we cannot acquire the cache chain mutex then just give up - we'll try
4180 * again on the next iteration.
4182 static void cache_reap(struct work_struct
*w
)
4184 struct kmem_cache
*searchp
;
4185 struct kmem_list3
*l3
;
4186 int node
= numa_mem_id();
4187 struct delayed_work
*work
= to_delayed_work(w
);
4189 if (!mutex_trylock(&cache_chain_mutex
))
4190 /* Give up. Setup the next iteration. */
4193 list_for_each_entry(searchp
, &cache_chain
, list
) {
4197 * We only take the l3 lock if absolutely necessary and we
4198 * have established with reasonable certainty that
4199 * we can do some work if the lock was obtained.
4201 l3
= searchp
->nodelists
[node
];
4203 reap_alien(searchp
, l3
);
4205 drain_array(searchp
, l3
, cpu_cache_get(searchp
), 0, node
);
4208 * These are racy checks but it does not matter
4209 * if we skip one check or scan twice.
4211 if (time_after(l3
->next_reap
, jiffies
))
4214 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
;
4216 drain_array(searchp
, l3
, l3
->shared
, 0, node
);
4218 if (l3
->free_touched
)
4219 l3
->free_touched
= 0;
4223 freed
= drain_freelist(searchp
, l3
, (l3
->free_limit
+
4224 5 * searchp
->num
- 1) / (5 * searchp
->num
));
4225 STATS_ADD_REAPED(searchp
, freed
);
4231 mutex_unlock(&cache_chain_mutex
);
4234 /* Set up the next iteration */
4235 schedule_delayed_work(work
, round_jiffies_relative(REAPTIMEOUT_CPUC
));
4238 #ifdef CONFIG_SLABINFO
4240 static void print_slabinfo_header(struct seq_file
*m
)
4243 * Output format version, so at least we can change it
4244 * without _too_ many complaints.
4247 seq_puts(m
, "slabinfo - version: 2.1 (statistics)\n");
4249 seq_puts(m
, "slabinfo - version: 2.1\n");
4251 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> "
4252 "<objperslab> <pagesperslab>");
4253 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
4254 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4256 seq_puts(m
, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
4257 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
4258 seq_puts(m
, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
4263 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
4267 mutex_lock(&cache_chain_mutex
);
4269 print_slabinfo_header(m
);
4271 return seq_list_start(&cache_chain
, *pos
);
4274 static void *s_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
4276 return seq_list_next(p
, &cache_chain
, pos
);
4279 static void s_stop(struct seq_file
*m
, void *p
)
4281 mutex_unlock(&cache_chain_mutex
);
4284 static int s_show(struct seq_file
*m
, void *p
)
4286 struct kmem_cache
*cachep
= list_entry(p
, struct kmem_cache
, list
);
4288 unsigned long active_objs
;
4289 unsigned long num_objs
;
4290 unsigned long active_slabs
= 0;
4291 unsigned long num_slabs
, free_objects
= 0, shared_avail
= 0;
4295 struct kmem_list3
*l3
;
4299 for_each_online_node(node
) {
4300 l3
= cachep
->nodelists
[node
];
4305 spin_lock_irq(&l3
->list_lock
);
4307 list_for_each_entry(slabp
, &l3
->slabs_full
, list
) {
4308 if (slabp
->inuse
!= cachep
->num
&& !error
)
4309 error
= "slabs_full accounting error";
4310 active_objs
+= cachep
->num
;
4313 list_for_each_entry(slabp
, &l3
->slabs_partial
, list
) {
4314 if (slabp
->inuse
== cachep
->num
&& !error
)
4315 error
= "slabs_partial inuse accounting error";
4316 if (!slabp
->inuse
&& !error
)
4317 error
= "slabs_partial/inuse accounting error";
4318 active_objs
+= slabp
->inuse
;
4321 list_for_each_entry(slabp
, &l3
->slabs_free
, list
) {
4322 if (slabp
->inuse
&& !error
)
4323 error
= "slabs_free/inuse accounting error";
4326 free_objects
+= l3
->free_objects
;
4328 shared_avail
+= l3
->shared
->avail
;
4330 spin_unlock_irq(&l3
->list_lock
);
4332 num_slabs
+= active_slabs
;
4333 num_objs
= num_slabs
* cachep
->num
;
4334 if (num_objs
- active_objs
!= free_objects
&& !error
)
4335 error
= "free_objects accounting error";
4337 name
= cachep
->name
;
4339 printk(KERN_ERR
"slab: cache %s error: %s\n", name
, error
);
4341 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d",
4342 name
, active_objs
, num_objs
, cachep
->size
,
4343 cachep
->num
, (1 << cachep
->gfporder
));
4344 seq_printf(m
, " : tunables %4u %4u %4u",
4345 cachep
->limit
, cachep
->batchcount
, cachep
->shared
);
4346 seq_printf(m
, " : slabdata %6lu %6lu %6lu",
4347 active_slabs
, num_slabs
, shared_avail
);
4350 unsigned long high
= cachep
->high_mark
;
4351 unsigned long allocs
= cachep
->num_allocations
;
4352 unsigned long grown
= cachep
->grown
;
4353 unsigned long reaped
= cachep
->reaped
;
4354 unsigned long errors
= cachep
->errors
;
4355 unsigned long max_freeable
= cachep
->max_freeable
;
4356 unsigned long node_allocs
= cachep
->node_allocs
;
4357 unsigned long node_frees
= cachep
->node_frees
;
4358 unsigned long overflows
= cachep
->node_overflow
;
4360 seq_printf(m
, " : globalstat %7lu %6lu %5lu %4lu "
4361 "%4lu %4lu %4lu %4lu %4lu",
4362 allocs
, high
, grown
,
4363 reaped
, errors
, max_freeable
, node_allocs
,
4364 node_frees
, overflows
);
4368 unsigned long allochit
= atomic_read(&cachep
->allochit
);
4369 unsigned long allocmiss
= atomic_read(&cachep
->allocmiss
);
4370 unsigned long freehit
= atomic_read(&cachep
->freehit
);
4371 unsigned long freemiss
= atomic_read(&cachep
->freemiss
);
4373 seq_printf(m
, " : cpustat %6lu %6lu %6lu %6lu",
4374 allochit
, allocmiss
, freehit
, freemiss
);
4382 * slabinfo_op - iterator that generates /proc/slabinfo
4391 * num-pages-per-slab
4392 * + further values on SMP and with statistics enabled
4395 static const struct seq_operations slabinfo_op
= {
4402 #define MAX_SLABINFO_WRITE 128
4404 * slabinfo_write - Tuning for the slab allocator
4406 * @buffer: user buffer
4407 * @count: data length
4410 static ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
4411 size_t count
, loff_t
*ppos
)
4413 char kbuf
[MAX_SLABINFO_WRITE
+ 1], *tmp
;
4414 int limit
, batchcount
, shared
, res
;
4415 struct kmem_cache
*cachep
;
4417 if (count
> MAX_SLABINFO_WRITE
)
4419 if (copy_from_user(&kbuf
, buffer
, count
))
4421 kbuf
[MAX_SLABINFO_WRITE
] = '\0';
4423 tmp
= strchr(kbuf
, ' ');
4428 if (sscanf(tmp
, " %d %d %d", &limit
, &batchcount
, &shared
) != 3)
4431 /* Find the cache in the chain of caches. */
4432 mutex_lock(&cache_chain_mutex
);
4434 list_for_each_entry(cachep
, &cache_chain
, list
) {
4435 if (!strcmp(cachep
->name
, kbuf
)) {
4436 if (limit
< 1 || batchcount
< 1 ||
4437 batchcount
> limit
|| shared
< 0) {
4440 res
= do_tune_cpucache(cachep
, limit
,
4447 mutex_unlock(&cache_chain_mutex
);
4453 static int slabinfo_open(struct inode
*inode
, struct file
*file
)
4455 return seq_open(file
, &slabinfo_op
);
4458 static const struct file_operations proc_slabinfo_operations
= {
4459 .open
= slabinfo_open
,
4461 .write
= slabinfo_write
,
4462 .llseek
= seq_lseek
,
4463 .release
= seq_release
,
4466 #ifdef CONFIG_DEBUG_SLAB_LEAK
4468 static void *leaks_start(struct seq_file
*m
, loff_t
*pos
)
4470 mutex_lock(&cache_chain_mutex
);
4471 return seq_list_start(&cache_chain
, *pos
);
4474 static inline int add_caller(unsigned long *n
, unsigned long v
)
4484 unsigned long *q
= p
+ 2 * i
;
4498 memmove(p
+ 2, p
, n
[1] * 2 * sizeof(unsigned long) - ((void *)p
- (void *)n
));
4504 static void handle_slab(unsigned long *n
, struct kmem_cache
*c
, struct slab
*s
)
4510 for (i
= 0, p
= s
->s_mem
; i
< c
->num
; i
++, p
+= c
->size
) {
4511 if (slab_bufctl(s
)[i
] != BUFCTL_ACTIVE
)
4513 if (!add_caller(n
, (unsigned long)*dbg_userword(c
, p
)))
4518 static void show_symbol(struct seq_file
*m
, unsigned long address
)
4520 #ifdef CONFIG_KALLSYMS
4521 unsigned long offset
, size
;
4522 char modname
[MODULE_NAME_LEN
], name
[KSYM_NAME_LEN
];
4524 if (lookup_symbol_attrs(address
, &size
, &offset
, modname
, name
) == 0) {
4525 seq_printf(m
, "%s+%#lx/%#lx", name
, offset
, size
);
4527 seq_printf(m
, " [%s]", modname
);
4531 seq_printf(m
, "%p", (void *)address
);
4534 static int leaks_show(struct seq_file
*m
, void *p
)
4536 struct kmem_cache
*cachep
= list_entry(p
, struct kmem_cache
, next
);
4538 struct kmem_list3
*l3
;
4540 unsigned long *n
= m
->private;
4544 if (!(cachep
->flags
& SLAB_STORE_USER
))
4546 if (!(cachep
->flags
& SLAB_RED_ZONE
))
4549 /* OK, we can do it */
4553 for_each_online_node(node
) {
4554 l3
= cachep
->nodelists
[node
];
4559 spin_lock_irq(&l3
->list_lock
);
4561 list_for_each_entry(slabp
, &l3
->slabs_full
, list
)
4562 handle_slab(n
, cachep
, slabp
);
4563 list_for_each_entry(slabp
, &l3
->slabs_partial
, list
)
4564 handle_slab(n
, cachep
, slabp
);
4565 spin_unlock_irq(&l3
->list_lock
);
4567 name
= cachep
->name
;
4569 /* Increase the buffer size */
4570 mutex_unlock(&cache_chain_mutex
);
4571 m
->private = kzalloc(n
[0] * 4 * sizeof(unsigned long), GFP_KERNEL
);
4573 /* Too bad, we are really out */
4575 mutex_lock(&cache_chain_mutex
);
4578 *(unsigned long *)m
->private = n
[0] * 2;
4580 mutex_lock(&cache_chain_mutex
);
4581 /* Now make sure this entry will be retried */
4585 for (i
= 0; i
< n
[1]; i
++) {
4586 seq_printf(m
, "%s: %lu ", name
, n
[2*i
+3]);
4587 show_symbol(m
, n
[2*i
+2]);
4594 static const struct seq_operations slabstats_op
= {
4595 .start
= leaks_start
,
4601 static int slabstats_open(struct inode
*inode
, struct file
*file
)
4603 unsigned long *n
= kzalloc(PAGE_SIZE
, GFP_KERNEL
);
4606 ret
= seq_open(file
, &slabstats_op
);
4608 struct seq_file
*m
= file
->private_data
;
4609 *n
= PAGE_SIZE
/ (2 * sizeof(unsigned long));
4618 static const struct file_operations proc_slabstats_operations
= {
4619 .open
= slabstats_open
,
4621 .llseek
= seq_lseek
,
4622 .release
= seq_release_private
,
4626 static int __init
slab_proc_init(void)
4628 proc_create("slabinfo",S_IWUSR
|S_IRUSR
,NULL
,&proc_slabinfo_operations
);
4629 #ifdef CONFIG_DEBUG_SLAB_LEAK
4630 proc_create("slab_allocators", 0, NULL
, &proc_slabstats_operations
);
4634 module_init(slab_proc_init
);
4638 * ksize - get the actual amount of memory allocated for a given object
4639 * @objp: Pointer to the object
4641 * kmalloc may internally round up allocations and return more memory
4642 * than requested. ksize() can be used to determine the actual amount of
4643 * memory allocated. The caller may use this additional memory, even though
4644 * a smaller amount of memory was initially specified with the kmalloc call.
4645 * The caller must guarantee that objp points to a valid object previously
4646 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4647 * must not be freed during the duration of the call.
4649 size_t ksize(const void *objp
)
4652 if (unlikely(objp
== ZERO_SIZE_PTR
))
4655 return virt_to_cache(objp
)->object_size
;
4657 EXPORT_SYMBOL(ksize
);