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 intializations 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/config.h>
90 #include <linux/slab.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/seq_file.h>
98 #include <linux/notifier.h>
99 #include <linux/kallsyms.h>
100 #include <linux/cpu.h>
101 #include <linux/sysctl.h>
102 #include <linux/module.h>
103 #include <linux/rcupdate.h>
104 #include <linux/string.h>
105 #include <linux/nodemask.h>
106 #include <linux/mempolicy.h>
107 #include <linux/mutex.h>
109 #include <asm/uaccess.h>
110 #include <asm/cacheflush.h>
111 #include <asm/tlbflush.h>
112 #include <asm/page.h>
115 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
116 * SLAB_RED_ZONE & SLAB_POISON.
117 * 0 for faster, smaller code (especially in the critical paths).
119 * STATS - 1 to collect stats for /proc/slabinfo.
120 * 0 for faster, smaller code (especially in the critical paths).
122 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
125 #ifdef CONFIG_DEBUG_SLAB
128 #define FORCED_DEBUG 1
132 #define FORCED_DEBUG 0
135 /* Shouldn't this be in a header file somewhere? */
136 #define BYTES_PER_WORD sizeof(void *)
138 #ifndef cache_line_size
139 #define cache_line_size() L1_CACHE_BYTES
142 #ifndef ARCH_KMALLOC_MINALIGN
144 * Enforce a minimum alignment for the kmalloc caches.
145 * Usually, the kmalloc caches are cache_line_size() aligned, except when
146 * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
147 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
148 * alignment larger than BYTES_PER_WORD. ARCH_KMALLOC_MINALIGN allows that.
149 * Note that this flag disables some debug features.
151 #define ARCH_KMALLOC_MINALIGN 0
154 #ifndef ARCH_SLAB_MINALIGN
156 * Enforce a minimum alignment for all caches.
157 * Intended for archs that get misalignment faults even for BYTES_PER_WORD
158 * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
159 * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
160 * some debug features.
162 #define ARCH_SLAB_MINALIGN 0
165 #ifndef ARCH_KMALLOC_FLAGS
166 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
169 /* Legal flag mask for kmem_cache_create(). */
171 # define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
172 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
173 SLAB_NO_REAP | SLAB_CACHE_DMA | \
174 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \
175 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
178 # define CREATE_MASK (SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \
179 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \
180 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
187 * Bufctl's are used for linking objs within a slab
190 * This implementation relies on "struct page" for locating the cache &
191 * slab an object belongs to.
192 * This allows the bufctl structure to be small (one int), but limits
193 * the number of objects a slab (not a cache) can contain when off-slab
194 * bufctls are used. The limit is the size of the largest general cache
195 * that does not use off-slab slabs.
196 * For 32bit archs with 4 kB pages, is this 56.
197 * This is not serious, as it is only for large objects, when it is unwise
198 * to have too many per slab.
199 * Note: This limit can be raised by introducing a general cache whose size
200 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
203 typedef unsigned int kmem_bufctl_t
;
204 #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
205 #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
206 #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-2)
208 /* Max number of objs-per-slab for caches which use off-slab slabs.
209 * Needed to avoid a possible looping condition in cache_grow().
211 static unsigned long offslab_limit
;
216 * Manages the objs in a slab. Placed either at the beginning of mem allocated
217 * for a slab, or allocated from an general cache.
218 * Slabs are chained into three list: fully used, partial, fully free slabs.
221 struct list_head list
;
222 unsigned long colouroff
;
223 void *s_mem
; /* including colour offset */
224 unsigned int inuse
; /* num of objs active in slab */
226 unsigned short nodeid
;
232 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
233 * arrange for kmem_freepages to be called via RCU. This is useful if
234 * we need to approach a kernel structure obliquely, from its address
235 * obtained without the usual locking. We can lock the structure to
236 * stabilize it and check it's still at the given address, only if we
237 * can be sure that the memory has not been meanwhile reused for some
238 * other kind of object (which our subsystem's lock might corrupt).
240 * rcu_read_lock before reading the address, then rcu_read_unlock after
241 * taking the spinlock within the structure expected at that address.
243 * We assume struct slab_rcu can overlay struct slab when destroying.
246 struct rcu_head head
;
247 struct kmem_cache
*cachep
;
255 * - LIFO ordering, to hand out cache-warm objects from _alloc
256 * - reduce the number of linked list operations
257 * - reduce spinlock operations
259 * The limit is stored in the per-cpu structure to reduce the data cache
266 unsigned int batchcount
;
267 unsigned int touched
;
270 * Must have this definition in here for the proper
271 * alignment of array_cache. Also simplifies accessing
273 * [0] is for gcc 2.95. It should really be [].
277 /* bootstrap: The caches do not work without cpuarrays anymore,
278 * but the cpuarrays are allocated from the generic caches...
280 #define BOOT_CPUCACHE_ENTRIES 1
281 struct arraycache_init
{
282 struct array_cache cache
;
283 void *entries
[BOOT_CPUCACHE_ENTRIES
];
287 * The slab lists for all objects.
290 struct list_head slabs_partial
; /* partial list first, better asm code */
291 struct list_head slabs_full
;
292 struct list_head slabs_free
;
293 unsigned long free_objects
;
294 unsigned long next_reap
;
296 unsigned int free_limit
;
297 spinlock_t list_lock
;
298 struct array_cache
*shared
; /* shared per node */
299 struct array_cache
**alien
; /* on other nodes */
303 * Need this for bootstrapping a per node allocator.
305 #define NUM_INIT_LISTS (2 * MAX_NUMNODES + 1)
306 struct kmem_list3 __initdata initkmem_list3
[NUM_INIT_LISTS
];
307 #define CACHE_CACHE 0
309 #define SIZE_L3 (1 + MAX_NUMNODES)
312 * This function must be completely optimized away if
313 * a constant is passed to it. Mostly the same as
314 * what is in linux/slab.h except it returns an
317 static __always_inline
int index_of(const size_t size
)
319 extern void __bad_size(void);
321 if (__builtin_constant_p(size
)) {
329 #include "linux/kmalloc_sizes.h"
337 #define INDEX_AC index_of(sizeof(struct arraycache_init))
338 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
340 static void kmem_list3_init(struct kmem_list3
*parent
)
342 INIT_LIST_HEAD(&parent
->slabs_full
);
343 INIT_LIST_HEAD(&parent
->slabs_partial
);
344 INIT_LIST_HEAD(&parent
->slabs_free
);
345 parent
->shared
= NULL
;
346 parent
->alien
= NULL
;
347 spin_lock_init(&parent
->list_lock
);
348 parent
->free_objects
= 0;
349 parent
->free_touched
= 0;
352 #define MAKE_LIST(cachep, listp, slab, nodeid) \
354 INIT_LIST_HEAD(listp); \
355 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
358 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
360 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
361 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
362 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
372 /* 1) per-cpu data, touched during every alloc/free */
373 struct array_cache
*array
[NR_CPUS
];
374 unsigned int batchcount
;
377 unsigned int buffer_size
;
378 /* 2) touched by every alloc & free from the backend */
379 struct kmem_list3
*nodelists
[MAX_NUMNODES
];
380 unsigned int flags
; /* constant flags */
381 unsigned int num
; /* # of objs per slab */
384 /* 3) cache_grow/shrink */
385 /* order of pgs per slab (2^n) */
386 unsigned int gfporder
;
388 /* force GFP flags, e.g. GFP_DMA */
391 size_t colour
; /* cache colouring range */
392 unsigned int colour_off
; /* colour offset */
393 unsigned int colour_next
; /* cache colouring */
394 struct kmem_cache
*slabp_cache
;
395 unsigned int slab_size
;
396 unsigned int dflags
; /* dynamic flags */
398 /* constructor func */
399 void (*ctor
) (void *, struct kmem_cache
*, unsigned long);
401 /* de-constructor func */
402 void (*dtor
) (void *, struct kmem_cache
*, unsigned long);
404 /* 4) cache creation/removal */
406 struct list_head next
;
410 unsigned long num_active
;
411 unsigned long num_allocations
;
412 unsigned long high_mark
;
414 unsigned long reaped
;
415 unsigned long errors
;
416 unsigned long max_freeable
;
417 unsigned long node_allocs
;
418 unsigned long node_frees
;
426 * If debugging is enabled, then the allocator can add additional
427 * fields and/or padding to every object. buffer_size contains the total
428 * object size including these internal fields, the following two
429 * variables contain the offset to the user object and its size.
436 #define CFLGS_OFF_SLAB (0x80000000UL)
437 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
439 #define BATCHREFILL_LIMIT 16
440 /* Optimization question: fewer reaps means less
441 * probability for unnessary cpucache drain/refill cycles.
443 * OTOH the cpuarrays can contain lots of objects,
444 * which could lock up otherwise freeable slabs.
446 #define REAPTIMEOUT_CPUC (2*HZ)
447 #define REAPTIMEOUT_LIST3 (4*HZ)
450 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
451 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
452 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
453 #define STATS_INC_GROWN(x) ((x)->grown++)
454 #define STATS_INC_REAPED(x) ((x)->reaped++)
455 #define STATS_SET_HIGH(x) do { if ((x)->num_active > (x)->high_mark) \
456 (x)->high_mark = (x)->num_active; \
458 #define STATS_INC_ERR(x) ((x)->errors++)
459 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
460 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
461 #define STATS_SET_FREEABLE(x, i) \
462 do { if ((x)->max_freeable < i) \
463 (x)->max_freeable = i; \
466 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
467 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
468 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
469 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
471 #define STATS_INC_ACTIVE(x) do { } while (0)
472 #define STATS_DEC_ACTIVE(x) do { } while (0)
473 #define STATS_INC_ALLOCED(x) do { } while (0)
474 #define STATS_INC_GROWN(x) do { } while (0)
475 #define STATS_INC_REAPED(x) do { } while (0)
476 #define STATS_SET_HIGH(x) do { } while (0)
477 #define STATS_INC_ERR(x) do { } while (0)
478 #define STATS_INC_NODEALLOCS(x) do { } while (0)
479 #define STATS_INC_NODEFREES(x) do { } while (0)
480 #define STATS_SET_FREEABLE(x, i) \
483 #define STATS_INC_ALLOCHIT(x) do { } while (0)
484 #define STATS_INC_ALLOCMISS(x) do { } while (0)
485 #define STATS_INC_FREEHIT(x) do { } while (0)
486 #define STATS_INC_FREEMISS(x) do { } while (0)
490 /* Magic nums for obj red zoning.
491 * Placed in the first word before and the first word after an obj.
493 #define RED_INACTIVE 0x5A2CF071UL /* when obj is inactive */
494 #define RED_ACTIVE 0x170FC2A5UL /* when obj is active */
496 /* ...and for poisoning */
497 #define POISON_INUSE 0x5a /* for use-uninitialised poisoning */
498 #define POISON_FREE 0x6b /* for use-after-free poisoning */
499 #define POISON_END 0xa5 /* end-byte of poisoning */
501 /* memory layout of objects:
503 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
504 * the end of an object is aligned with the end of the real
505 * allocation. Catches writes behind the end of the allocation.
506 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
508 * cachep->obj_offset: The real object.
509 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
510 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address [BYTES_PER_WORD long]
512 static int obj_offset(struct kmem_cache
*cachep
)
514 return cachep
->obj_offset
;
517 static int obj_size(struct kmem_cache
*cachep
)
519 return cachep
->obj_size
;
522 static unsigned long *dbg_redzone1(struct kmem_cache
*cachep
, void *objp
)
524 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
525 return (unsigned long*) (objp
+obj_offset(cachep
)-BYTES_PER_WORD
);
528 static unsigned long *dbg_redzone2(struct kmem_cache
*cachep
, void *objp
)
530 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
531 if (cachep
->flags
& SLAB_STORE_USER
)
532 return (unsigned long *)(objp
+ cachep
->buffer_size
-
534 return (unsigned long *)(objp
+ cachep
->buffer_size
- BYTES_PER_WORD
);
537 static void **dbg_userword(struct kmem_cache
*cachep
, void *objp
)
539 BUG_ON(!(cachep
->flags
& SLAB_STORE_USER
));
540 return (void **)(objp
+ cachep
->buffer_size
- BYTES_PER_WORD
);
545 #define obj_offset(x) 0
546 #define obj_size(cachep) (cachep->buffer_size)
547 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long *)NULL;})
548 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long *)NULL;})
549 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
554 * Maximum size of an obj (in 2^order pages)
555 * and absolute limit for the gfp order.
557 #if defined(CONFIG_LARGE_ALLOCS)
558 #define MAX_OBJ_ORDER 13 /* up to 32Mb */
559 #define MAX_GFP_ORDER 13 /* up to 32Mb */
560 #elif defined(CONFIG_MMU)
561 #define MAX_OBJ_ORDER 5 /* 32 pages */
562 #define MAX_GFP_ORDER 5 /* 32 pages */
564 #define MAX_OBJ_ORDER 8 /* up to 1Mb */
565 #define MAX_GFP_ORDER 8 /* up to 1Mb */
569 * Do not go above this order unless 0 objects fit into the slab.
571 #define BREAK_GFP_ORDER_HI 1
572 #define BREAK_GFP_ORDER_LO 0
573 static int slab_break_gfp_order
= BREAK_GFP_ORDER_LO
;
575 /* Functions for storing/retrieving the cachep and or slab from the
576 * global 'mem_map'. These are used to find the slab an obj belongs to.
577 * With kfree(), these are used to find the cache which an obj belongs to.
579 static inline void page_set_cache(struct page
*page
, struct kmem_cache
*cache
)
581 page
->lru
.next
= (struct list_head
*)cache
;
584 static inline struct kmem_cache
*page_get_cache(struct page
*page
)
586 return (struct kmem_cache
*)page
->lru
.next
;
589 static inline void page_set_slab(struct page
*page
, struct slab
*slab
)
591 page
->lru
.prev
= (struct list_head
*)slab
;
594 static inline struct slab
*page_get_slab(struct page
*page
)
596 return (struct slab
*)page
->lru
.prev
;
599 static inline struct kmem_cache
*virt_to_cache(const void *obj
)
601 struct page
*page
= virt_to_page(obj
);
602 return page_get_cache(page
);
605 static inline struct slab
*virt_to_slab(const void *obj
)
607 struct page
*page
= virt_to_page(obj
);
608 return page_get_slab(page
);
611 /* These are the default caches for kmalloc. Custom caches can have other sizes. */
612 struct cache_sizes malloc_sizes
[] = {
613 #define CACHE(x) { .cs_size = (x) },
614 #include <linux/kmalloc_sizes.h>
618 EXPORT_SYMBOL(malloc_sizes
);
620 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
626 static struct cache_names __initdata cache_names
[] = {
627 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
628 #include <linux/kmalloc_sizes.h>
633 static struct arraycache_init initarray_cache __initdata
=
634 { {0, BOOT_CPUCACHE_ENTRIES
, 1, 0} };
635 static struct arraycache_init initarray_generic
=
636 { {0, BOOT_CPUCACHE_ENTRIES
, 1, 0} };
638 /* internal cache of cache description objs */
639 static struct kmem_cache cache_cache
= {
641 .limit
= BOOT_CPUCACHE_ENTRIES
,
643 .buffer_size
= sizeof(struct kmem_cache
),
644 .flags
= SLAB_NO_REAP
,
645 .spinlock
= SPIN_LOCK_UNLOCKED
,
646 .name
= "kmem_cache",
648 .obj_size
= sizeof(struct kmem_cache
),
652 /* Guard access to the cache-chain. */
653 static DEFINE_MUTEX(cache_chain_mutex
);
654 static struct list_head cache_chain
;
657 * vm_enough_memory() looks at this to determine how many
658 * slab-allocated pages are possibly freeable under pressure
660 * SLAB_RECLAIM_ACCOUNT turns this on per-slab
662 atomic_t slab_reclaim_pages
;
665 * chicken and egg problem: delay the per-cpu array allocation
666 * until the general caches are up.
675 static DEFINE_PER_CPU(struct work_struct
, reap_work
);
677 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int len
, int node
);
678 static void enable_cpucache(struct kmem_cache
*cachep
);
679 static void cache_reap(void *unused
);
680 static int __node_shrink(struct kmem_cache
*cachep
, int node
);
682 static inline struct array_cache
*cpu_cache_get(struct kmem_cache
*cachep
)
684 return cachep
->array
[smp_processor_id()];
687 static inline struct kmem_cache
*__find_general_cachep(size_t size
, gfp_t gfpflags
)
689 struct cache_sizes
*csizep
= malloc_sizes
;
692 /* This happens if someone tries to call
693 * kmem_cache_create(), or __kmalloc(), before
694 * the generic caches are initialized.
696 BUG_ON(malloc_sizes
[INDEX_AC
].cs_cachep
== NULL
);
698 while (size
> csizep
->cs_size
)
702 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
703 * has cs_{dma,}cachep==NULL. Thus no special case
704 * for large kmalloc calls required.
706 if (unlikely(gfpflags
& GFP_DMA
))
707 return csizep
->cs_dmacachep
;
708 return csizep
->cs_cachep
;
711 struct kmem_cache
*kmem_find_general_cachep(size_t size
, gfp_t gfpflags
)
713 return __find_general_cachep(size
, gfpflags
);
715 EXPORT_SYMBOL(kmem_find_general_cachep
);
717 static size_t slab_mgmt_size(size_t nr_objs
, size_t align
)
719 return ALIGN(sizeof(struct slab
)+nr_objs
*sizeof(kmem_bufctl_t
), align
);
722 /* Calculate the number of objects and left-over bytes for a given
724 static void cache_estimate(unsigned long gfporder
, size_t buffer_size
,
725 size_t align
, int flags
, size_t *left_over
,
730 size_t slab_size
= PAGE_SIZE
<< gfporder
;
733 * The slab management structure can be either off the slab or
734 * on it. For the latter case, the memory allocated for a
738 * - One kmem_bufctl_t for each object
739 * - Padding to respect alignment of @align
740 * - @buffer_size bytes for each object
742 * If the slab management structure is off the slab, then the
743 * alignment will already be calculated into the size. Because
744 * the slabs are all pages aligned, the objects will be at the
745 * correct alignment when allocated.
747 if (flags
& CFLGS_OFF_SLAB
) {
749 nr_objs
= slab_size
/ buffer_size
;
751 if (nr_objs
> SLAB_LIMIT
)
752 nr_objs
= SLAB_LIMIT
;
755 * Ignore padding for the initial guess. The padding
756 * is at most @align-1 bytes, and @buffer_size is at
757 * least @align. In the worst case, this result will
758 * be one greater than the number of objects that fit
759 * into the memory allocation when taking the padding
762 nr_objs
= (slab_size
- sizeof(struct slab
)) /
763 (buffer_size
+ sizeof(kmem_bufctl_t
));
766 * This calculated number will be either the right
767 * amount, or one greater than what we want.
769 if (slab_mgmt_size(nr_objs
, align
) + nr_objs
*buffer_size
773 if (nr_objs
> SLAB_LIMIT
)
774 nr_objs
= SLAB_LIMIT
;
776 mgmt_size
= slab_mgmt_size(nr_objs
, align
);
779 *left_over
= slab_size
- nr_objs
*buffer_size
- mgmt_size
;
782 #define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg)
784 static void __slab_error(const char *function
, struct kmem_cache
*cachep
, char *msg
)
786 printk(KERN_ERR
"slab error in %s(): cache `%s': %s\n",
787 function
, cachep
->name
, msg
);
792 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
793 * via the workqueue/eventd.
794 * Add the CPU number into the expiration time to minimize the possibility of
795 * the CPUs getting into lockstep and contending for the global cache chain
798 static void __devinit
start_cpu_timer(int cpu
)
800 struct work_struct
*reap_work
= &per_cpu(reap_work
, cpu
);
803 * When this gets called from do_initcalls via cpucache_init(),
804 * init_workqueues() has already run, so keventd will be setup
807 if (keventd_up() && reap_work
->func
== NULL
) {
808 INIT_WORK(reap_work
, cache_reap
, NULL
);
809 schedule_delayed_work_on(cpu
, reap_work
, HZ
+ 3 * cpu
);
813 static struct array_cache
*alloc_arraycache(int node
, int entries
,
816 int memsize
= sizeof(void *) * entries
+ sizeof(struct array_cache
);
817 struct array_cache
*nc
= NULL
;
819 nc
= kmalloc_node(memsize
, GFP_KERNEL
, node
);
823 nc
->batchcount
= batchcount
;
825 spin_lock_init(&nc
->lock
);
831 static void *__cache_alloc_node(struct kmem_cache
*, gfp_t
, int);
833 static struct array_cache
**alloc_alien_cache(int node
, int limit
)
835 struct array_cache
**ac_ptr
;
836 int memsize
= sizeof(void *) * MAX_NUMNODES
;
841 ac_ptr
= kmalloc_node(memsize
, GFP_KERNEL
, node
);
844 if (i
== node
|| !node_online(i
)) {
848 ac_ptr
[i
] = alloc_arraycache(node
, limit
, 0xbaadf00d);
850 for (i
--; i
<= 0; i
--)
860 static void free_alien_cache(struct array_cache
**ac_ptr
)
873 static void __drain_alien_cache(struct kmem_cache
*cachep
,
874 struct array_cache
*ac
, int node
)
876 struct kmem_list3
*rl3
= cachep
->nodelists
[node
];
879 spin_lock(&rl3
->list_lock
);
880 free_block(cachep
, ac
->entry
, ac
->avail
, node
);
882 spin_unlock(&rl3
->list_lock
);
886 static void drain_alien_cache(struct kmem_cache
*cachep
, struct kmem_list3
*l3
)
889 struct array_cache
*ac
;
892 for_each_online_node(i
) {
895 spin_lock_irqsave(&ac
->lock
, flags
);
896 __drain_alien_cache(cachep
, ac
, i
);
897 spin_unlock_irqrestore(&ac
->lock
, flags
);
902 #define alloc_alien_cache(node, limit) do { } while (0)
903 #define free_alien_cache(ac_ptr) do { } while (0)
904 #define drain_alien_cache(cachep, l3) do { } while (0)
907 static int __devinit
cpuup_callback(struct notifier_block
*nfb
,
908 unsigned long action
, void *hcpu
)
910 long cpu
= (long)hcpu
;
911 struct kmem_cache
*cachep
;
912 struct kmem_list3
*l3
= NULL
;
913 int node
= cpu_to_node(cpu
);
914 int memsize
= sizeof(struct kmem_list3
);
918 mutex_lock(&cache_chain_mutex
);
919 /* we need to do this right in the beginning since
920 * alloc_arraycache's are going to use this list.
921 * kmalloc_node allows us to add the slab to the right
922 * kmem_list3 and not this cpu's kmem_list3
925 list_for_each_entry(cachep
, &cache_chain
, next
) {
926 /* setup the size64 kmemlist for cpu before we can
927 * begin anything. Make sure some other cpu on this
928 * node has not already allocated this
930 if (!cachep
->nodelists
[node
]) {
931 if (!(l3
= kmalloc_node(memsize
,
935 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
+
936 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
938 cachep
->nodelists
[node
] = l3
;
941 spin_lock_irq(&cachep
->nodelists
[node
]->list_lock
);
942 cachep
->nodelists
[node
]->free_limit
=
943 (1 + nr_cpus_node(node
)) *
944 cachep
->batchcount
+ cachep
->num
;
945 spin_unlock_irq(&cachep
->nodelists
[node
]->list_lock
);
948 /* Now we can go ahead with allocating the shared array's
950 list_for_each_entry(cachep
, &cache_chain
, next
) {
951 struct array_cache
*nc
;
953 nc
= alloc_arraycache(node
, cachep
->limit
,
957 cachep
->array
[cpu
] = nc
;
959 l3
= cachep
->nodelists
[node
];
962 if (!(nc
= alloc_arraycache(node
,
968 /* we are serialised from CPU_DEAD or
969 CPU_UP_CANCELLED by the cpucontrol lock */
973 mutex_unlock(&cache_chain_mutex
);
976 start_cpu_timer(cpu
);
978 #ifdef CONFIG_HOTPLUG_CPU
981 case CPU_UP_CANCELED
:
982 mutex_lock(&cache_chain_mutex
);
984 list_for_each_entry(cachep
, &cache_chain
, next
) {
985 struct array_cache
*nc
;
988 mask
= node_to_cpumask(node
);
989 spin_lock_irq(&cachep
->spinlock
);
990 /* cpu is dead; no one can alloc from it. */
991 nc
= cachep
->array
[cpu
];
992 cachep
->array
[cpu
] = NULL
;
993 l3
= cachep
->nodelists
[node
];
998 spin_lock(&l3
->list_lock
);
1000 /* Free limit for this kmem_list3 */
1001 l3
->free_limit
-= cachep
->batchcount
;
1003 free_block(cachep
, nc
->entry
, nc
->avail
, node
);
1005 if (!cpus_empty(mask
)) {
1006 spin_unlock(&l3
->list_lock
);
1011 free_block(cachep
, l3
->shared
->entry
,
1012 l3
->shared
->avail
, node
);
1017 drain_alien_cache(cachep
, l3
);
1018 free_alien_cache(l3
->alien
);
1022 /* free slabs belonging to this node */
1023 if (__node_shrink(cachep
, node
)) {
1024 cachep
->nodelists
[node
] = NULL
;
1025 spin_unlock(&l3
->list_lock
);
1028 spin_unlock(&l3
->list_lock
);
1031 spin_unlock_irq(&cachep
->spinlock
);
1034 mutex_unlock(&cache_chain_mutex
);
1040 mutex_unlock(&cache_chain_mutex
);
1044 static struct notifier_block cpucache_notifier
= { &cpuup_callback
, NULL
, 0 };
1047 * swap the static kmem_list3 with kmalloced memory
1049 static void init_list(struct kmem_cache
*cachep
, struct kmem_list3
*list
, int nodeid
)
1051 struct kmem_list3
*ptr
;
1053 BUG_ON(cachep
->nodelists
[nodeid
] != list
);
1054 ptr
= kmalloc_node(sizeof(struct kmem_list3
), GFP_KERNEL
, nodeid
);
1057 local_irq_disable();
1058 memcpy(ptr
, list
, sizeof(struct kmem_list3
));
1059 MAKE_ALL_LISTS(cachep
, ptr
, nodeid
);
1060 cachep
->nodelists
[nodeid
] = ptr
;
1065 * Called after the gfp() functions have been enabled, and before smp_init().
1067 void __init
kmem_cache_init(void)
1070 struct cache_sizes
*sizes
;
1071 struct cache_names
*names
;
1074 for (i
= 0; i
< NUM_INIT_LISTS
; i
++) {
1075 kmem_list3_init(&initkmem_list3
[i
]);
1076 if (i
< MAX_NUMNODES
)
1077 cache_cache
.nodelists
[i
] = NULL
;
1081 * Fragmentation resistance on low memory - only use bigger
1082 * page orders on machines with more than 32MB of memory.
1084 if (num_physpages
> (32 << 20) >> PAGE_SHIFT
)
1085 slab_break_gfp_order
= BREAK_GFP_ORDER_HI
;
1087 /* Bootstrap is tricky, because several objects are allocated
1088 * from caches that do not exist yet:
1089 * 1) initialize the cache_cache cache: it contains the struct kmem_cache
1090 * structures of all caches, except cache_cache itself: cache_cache
1091 * is statically allocated.
1092 * Initially an __init data area is used for the head array and the
1093 * kmem_list3 structures, it's replaced with a kmalloc allocated
1094 * array at the end of the bootstrap.
1095 * 2) Create the first kmalloc cache.
1096 * The struct kmem_cache for the new cache is allocated normally.
1097 * An __init data area is used for the head array.
1098 * 3) Create the remaining kmalloc caches, with minimally sized
1100 * 4) Replace the __init data head arrays for cache_cache and the first
1101 * kmalloc cache with kmalloc allocated arrays.
1102 * 5) Replace the __init data for kmem_list3 for cache_cache and
1103 * the other cache's with kmalloc allocated memory.
1104 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1107 /* 1) create the cache_cache */
1108 INIT_LIST_HEAD(&cache_chain
);
1109 list_add(&cache_cache
.next
, &cache_chain
);
1110 cache_cache
.colour_off
= cache_line_size();
1111 cache_cache
.array
[smp_processor_id()] = &initarray_cache
.cache
;
1112 cache_cache
.nodelists
[numa_node_id()] = &initkmem_list3
[CACHE_CACHE
];
1114 cache_cache
.buffer_size
= ALIGN(cache_cache
.buffer_size
, cache_line_size());
1116 cache_estimate(0, cache_cache
.buffer_size
, cache_line_size(), 0,
1117 &left_over
, &cache_cache
.num
);
1118 if (!cache_cache
.num
)
1121 cache_cache
.colour
= left_over
/ cache_cache
.colour_off
;
1122 cache_cache
.colour_next
= 0;
1123 cache_cache
.slab_size
= ALIGN(cache_cache
.num
* sizeof(kmem_bufctl_t
) +
1124 sizeof(struct slab
), cache_line_size());
1126 /* 2+3) create the kmalloc caches */
1127 sizes
= malloc_sizes
;
1128 names
= cache_names
;
1130 /* Initialize the caches that provide memory for the array cache
1131 * and the kmem_list3 structures first.
1132 * Without this, further allocations will bug
1135 sizes
[INDEX_AC
].cs_cachep
= kmem_cache_create(names
[INDEX_AC
].name
,
1136 sizes
[INDEX_AC
].cs_size
,
1137 ARCH_KMALLOC_MINALIGN
,
1138 (ARCH_KMALLOC_FLAGS
|
1139 SLAB_PANIC
), NULL
, NULL
);
1141 if (INDEX_AC
!= INDEX_L3
)
1142 sizes
[INDEX_L3
].cs_cachep
=
1143 kmem_cache_create(names
[INDEX_L3
].name
,
1144 sizes
[INDEX_L3
].cs_size
,
1145 ARCH_KMALLOC_MINALIGN
,
1146 (ARCH_KMALLOC_FLAGS
| SLAB_PANIC
), NULL
,
1149 while (sizes
->cs_size
!= ULONG_MAX
) {
1151 * For performance, all the general caches are L1 aligned.
1152 * This should be particularly beneficial on SMP boxes, as it
1153 * eliminates "false sharing".
1154 * Note for systems short on memory removing the alignment will
1155 * allow tighter packing of the smaller caches.
1157 if (!sizes
->cs_cachep
)
1158 sizes
->cs_cachep
= kmem_cache_create(names
->name
,
1160 ARCH_KMALLOC_MINALIGN
,
1165 /* Inc off-slab bufctl limit until the ceiling is hit. */
1166 if (!(OFF_SLAB(sizes
->cs_cachep
))) {
1167 offslab_limit
= sizes
->cs_size
- sizeof(struct slab
);
1168 offslab_limit
/= sizeof(kmem_bufctl_t
);
1171 sizes
->cs_dmacachep
= kmem_cache_create(names
->name_dma
,
1173 ARCH_KMALLOC_MINALIGN
,
1174 (ARCH_KMALLOC_FLAGS
|
1182 /* 4) Replace the bootstrap head arrays */
1186 ptr
= kmalloc(sizeof(struct arraycache_init
), GFP_KERNEL
);
1188 local_irq_disable();
1189 BUG_ON(cpu_cache_get(&cache_cache
) != &initarray_cache
.cache
);
1190 memcpy(ptr
, cpu_cache_get(&cache_cache
),
1191 sizeof(struct arraycache_init
));
1192 cache_cache
.array
[smp_processor_id()] = ptr
;
1195 ptr
= kmalloc(sizeof(struct arraycache_init
), GFP_KERNEL
);
1197 local_irq_disable();
1198 BUG_ON(cpu_cache_get(malloc_sizes
[INDEX_AC
].cs_cachep
)
1199 != &initarray_generic
.cache
);
1200 memcpy(ptr
, cpu_cache_get(malloc_sizes
[INDEX_AC
].cs_cachep
),
1201 sizeof(struct arraycache_init
));
1202 malloc_sizes
[INDEX_AC
].cs_cachep
->array
[smp_processor_id()] =
1206 /* 5) Replace the bootstrap kmem_list3's */
1209 /* Replace the static kmem_list3 structures for the boot cpu */
1210 init_list(&cache_cache
, &initkmem_list3
[CACHE_CACHE
],
1213 for_each_online_node(node
) {
1214 init_list(malloc_sizes
[INDEX_AC
].cs_cachep
,
1215 &initkmem_list3
[SIZE_AC
+ node
], node
);
1217 if (INDEX_AC
!= INDEX_L3
) {
1218 init_list(malloc_sizes
[INDEX_L3
].cs_cachep
,
1219 &initkmem_list3
[SIZE_L3
+ node
],
1225 /* 6) resize the head arrays to their final sizes */
1227 struct kmem_cache
*cachep
;
1228 mutex_lock(&cache_chain_mutex
);
1229 list_for_each_entry(cachep
, &cache_chain
, next
)
1230 enable_cpucache(cachep
);
1231 mutex_unlock(&cache_chain_mutex
);
1235 g_cpucache_up
= FULL
;
1237 /* Register a cpu startup notifier callback
1238 * that initializes cpu_cache_get for all new cpus
1240 register_cpu_notifier(&cpucache_notifier
);
1242 /* The reap timers are started later, with a module init call:
1243 * That part of the kernel is not yet operational.
1247 static int __init
cpucache_init(void)
1252 * Register the timers that return unneeded
1255 for_each_online_cpu(cpu
)
1256 start_cpu_timer(cpu
);
1261 __initcall(cpucache_init
);
1264 * Interface to system's page allocator. No need to hold the cache-lock.
1266 * If we requested dmaable memory, we will get it. Even if we
1267 * did not request dmaable memory, we might get it, but that
1268 * would be relatively rare and ignorable.
1270 static void *kmem_getpages(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
1276 flags
|= cachep
->gfpflags
;
1277 page
= alloc_pages_node(nodeid
, flags
, cachep
->gfporder
);
1280 addr
= page_address(page
);
1282 i
= (1 << cachep
->gfporder
);
1283 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1284 atomic_add(i
, &slab_reclaim_pages
);
1285 add_page_state(nr_slab
, i
);
1294 * Interface to system's page release.
1296 static void kmem_freepages(struct kmem_cache
*cachep
, void *addr
)
1298 unsigned long i
= (1 << cachep
->gfporder
);
1299 struct page
*page
= virt_to_page(addr
);
1300 const unsigned long nr_freed
= i
;
1303 if (!TestClearPageSlab(page
))
1307 sub_page_state(nr_slab
, nr_freed
);
1308 if (current
->reclaim_state
)
1309 current
->reclaim_state
->reclaimed_slab
+= nr_freed
;
1310 free_pages((unsigned long)addr
, cachep
->gfporder
);
1311 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1312 atomic_sub(1 << cachep
->gfporder
, &slab_reclaim_pages
);
1315 static void kmem_rcu_free(struct rcu_head
*head
)
1317 struct slab_rcu
*slab_rcu
= (struct slab_rcu
*)head
;
1318 struct kmem_cache
*cachep
= slab_rcu
->cachep
;
1320 kmem_freepages(cachep
, slab_rcu
->addr
);
1321 if (OFF_SLAB(cachep
))
1322 kmem_cache_free(cachep
->slabp_cache
, slab_rcu
);
1327 #ifdef CONFIG_DEBUG_PAGEALLOC
1328 static void store_stackinfo(struct kmem_cache
*cachep
, unsigned long *addr
,
1329 unsigned long caller
)
1331 int size
= obj_size(cachep
);
1333 addr
= (unsigned long *)&((char *)addr
)[obj_offset(cachep
)];
1335 if (size
< 5 * sizeof(unsigned long))
1338 *addr
++ = 0x12345678;
1340 *addr
++ = smp_processor_id();
1341 size
-= 3 * sizeof(unsigned long);
1343 unsigned long *sptr
= &caller
;
1344 unsigned long svalue
;
1346 while (!kstack_end(sptr
)) {
1348 if (kernel_text_address(svalue
)) {
1350 size
-= sizeof(unsigned long);
1351 if (size
<= sizeof(unsigned long))
1357 *addr
++ = 0x87654321;
1361 static void poison_obj(struct kmem_cache
*cachep
, void *addr
, unsigned char val
)
1363 int size
= obj_size(cachep
);
1364 addr
= &((char *)addr
)[obj_offset(cachep
)];
1366 memset(addr
, val
, size
);
1367 *(unsigned char *)(addr
+ size
- 1) = POISON_END
;
1370 static void dump_line(char *data
, int offset
, int limit
)
1373 printk(KERN_ERR
"%03x:", offset
);
1374 for (i
= 0; i
< limit
; i
++) {
1375 printk(" %02x", (unsigned char)data
[offset
+ i
]);
1383 static void print_objinfo(struct kmem_cache
*cachep
, void *objp
, int lines
)
1388 if (cachep
->flags
& SLAB_RED_ZONE
) {
1389 printk(KERN_ERR
"Redzone: 0x%lx/0x%lx.\n",
1390 *dbg_redzone1(cachep
, objp
),
1391 *dbg_redzone2(cachep
, objp
));
1394 if (cachep
->flags
& SLAB_STORE_USER
) {
1395 printk(KERN_ERR
"Last user: [<%p>]",
1396 *dbg_userword(cachep
, objp
));
1397 print_symbol("(%s)",
1398 (unsigned long)*dbg_userword(cachep
, objp
));
1401 realobj
= (char *)objp
+ obj_offset(cachep
);
1402 size
= obj_size(cachep
);
1403 for (i
= 0; i
< size
&& lines
; i
+= 16, lines
--) {
1406 if (i
+ limit
> size
)
1408 dump_line(realobj
, i
, limit
);
1412 static void check_poison_obj(struct kmem_cache
*cachep
, void *objp
)
1418 realobj
= (char *)objp
+ obj_offset(cachep
);
1419 size
= obj_size(cachep
);
1421 for (i
= 0; i
< size
; i
++) {
1422 char exp
= POISON_FREE
;
1425 if (realobj
[i
] != exp
) {
1431 "Slab corruption: start=%p, len=%d\n",
1433 print_objinfo(cachep
, objp
, 0);
1435 /* Hexdump the affected line */
1438 if (i
+ limit
> size
)
1440 dump_line(realobj
, i
, limit
);
1443 /* Limit to 5 lines */
1449 /* Print some data about the neighboring objects, if they
1452 struct slab
*slabp
= virt_to_slab(objp
);
1455 objnr
= (unsigned)(objp
- slabp
->s_mem
) / cachep
->buffer_size
;
1457 objp
= slabp
->s_mem
+ (objnr
- 1) * cachep
->buffer_size
;
1458 realobj
= (char *)objp
+ obj_offset(cachep
);
1459 printk(KERN_ERR
"Prev obj: start=%p, len=%d\n",
1461 print_objinfo(cachep
, objp
, 2);
1463 if (objnr
+ 1 < cachep
->num
) {
1464 objp
= slabp
->s_mem
+ (objnr
+ 1) * cachep
->buffer_size
;
1465 realobj
= (char *)objp
+ obj_offset(cachep
);
1466 printk(KERN_ERR
"Next obj: start=%p, len=%d\n",
1468 print_objinfo(cachep
, objp
, 2);
1476 * slab_destroy_objs - call the registered destructor for each object in
1477 * a slab that is to be destroyed.
1479 static void slab_destroy_objs(struct kmem_cache
*cachep
, struct slab
*slabp
)
1482 for (i
= 0; i
< cachep
->num
; i
++) {
1483 void *objp
= slabp
->s_mem
+ cachep
->buffer_size
* i
;
1485 if (cachep
->flags
& SLAB_POISON
) {
1486 #ifdef CONFIG_DEBUG_PAGEALLOC
1487 if ((cachep
->buffer_size
% PAGE_SIZE
) == 0
1488 && OFF_SLAB(cachep
))
1489 kernel_map_pages(virt_to_page(objp
),
1490 cachep
->buffer_size
/ PAGE_SIZE
,
1493 check_poison_obj(cachep
, objp
);
1495 check_poison_obj(cachep
, objp
);
1498 if (cachep
->flags
& SLAB_RED_ZONE
) {
1499 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
1500 slab_error(cachep
, "start of a freed object "
1502 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
1503 slab_error(cachep
, "end of a freed object "
1506 if (cachep
->dtor
&& !(cachep
->flags
& SLAB_POISON
))
1507 (cachep
->dtor
) (objp
+ obj_offset(cachep
), cachep
, 0);
1511 static void slab_destroy_objs(struct kmem_cache
*cachep
, struct slab
*slabp
)
1515 for (i
= 0; i
< cachep
->num
; i
++) {
1516 void *objp
= slabp
->s_mem
+ cachep
->buffer_size
* i
;
1517 (cachep
->dtor
) (objp
, cachep
, 0);
1524 * Destroy all the objs in a slab, and release the mem back to the system.
1525 * Before calling the slab must have been unlinked from the cache.
1526 * The cache-lock is not held/needed.
1528 static void slab_destroy(struct kmem_cache
*cachep
, struct slab
*slabp
)
1530 void *addr
= slabp
->s_mem
- slabp
->colouroff
;
1532 slab_destroy_objs(cachep
, slabp
);
1533 if (unlikely(cachep
->flags
& SLAB_DESTROY_BY_RCU
)) {
1534 struct slab_rcu
*slab_rcu
;
1536 slab_rcu
= (struct slab_rcu
*)slabp
;
1537 slab_rcu
->cachep
= cachep
;
1538 slab_rcu
->addr
= addr
;
1539 call_rcu(&slab_rcu
->head
, kmem_rcu_free
);
1541 kmem_freepages(cachep
, addr
);
1542 if (OFF_SLAB(cachep
))
1543 kmem_cache_free(cachep
->slabp_cache
, slabp
);
1547 /* For setting up all the kmem_list3s for cache whose buffer_size is same
1548 as size of kmem_list3. */
1549 static void set_up_list3s(struct kmem_cache
*cachep
, int index
)
1553 for_each_online_node(node
) {
1554 cachep
->nodelists
[node
] = &initkmem_list3
[index
+ node
];
1555 cachep
->nodelists
[node
]->next_reap
= jiffies
+
1557 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
1562 * calculate_slab_order - calculate size (page order) of slabs and the number
1563 * of objects per slab.
1565 * This could be made much more intelligent. For now, try to avoid using
1566 * high order pages for slabs. When the gfp() functions are more friendly
1567 * towards high-order requests, this should be changed.
1569 static inline size_t calculate_slab_order(struct kmem_cache
*cachep
, size_t size
,
1570 size_t align
, gfp_t flags
)
1572 size_t left_over
= 0;
1574 for (;; cachep
->gfporder
++) {
1578 if (cachep
->gfporder
> MAX_GFP_ORDER
) {
1583 cache_estimate(cachep
->gfporder
, size
, align
, flags
,
1587 /* More than offslab_limit objects will cause problems */
1588 if (flags
& CFLGS_OFF_SLAB
&& cachep
->num
> offslab_limit
)
1592 left_over
= remainder
;
1595 * Large number of objects is good, but very large slabs are
1596 * currently bad for the gfp()s.
1598 if (cachep
->gfporder
>= slab_break_gfp_order
)
1601 if ((left_over
* 8) <= (PAGE_SIZE
<< cachep
->gfporder
))
1602 /* Acceptable internal fragmentation */
1609 * kmem_cache_create - Create a cache.
1610 * @name: A string which is used in /proc/slabinfo to identify this cache.
1611 * @size: The size of objects to be created in this cache.
1612 * @align: The required alignment for the objects.
1613 * @flags: SLAB flags
1614 * @ctor: A constructor for the objects.
1615 * @dtor: A destructor for the objects.
1617 * Returns a ptr to the cache on success, NULL on failure.
1618 * Cannot be called within a int, but can be interrupted.
1619 * The @ctor is run when new pages are allocated by the cache
1620 * and the @dtor is run before the pages are handed back.
1622 * @name must be valid until the cache is destroyed. This implies that
1623 * the module calling this has to destroy the cache before getting
1628 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
1629 * to catch references to uninitialised memory.
1631 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
1632 * for buffer overruns.
1634 * %SLAB_NO_REAP - Don't automatically reap this cache when we're under
1637 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
1638 * cacheline. This can be beneficial if you're counting cycles as closely
1642 kmem_cache_create (const char *name
, size_t size
, size_t align
,
1643 unsigned long flags
, void (*ctor
)(void*, struct kmem_cache
*, unsigned long),
1644 void (*dtor
)(void*, struct kmem_cache
*, unsigned long))
1646 size_t left_over
, slab_size
, ralign
;
1647 struct kmem_cache
*cachep
= NULL
;
1648 struct list_head
*p
;
1651 * Sanity checks... these are all serious usage bugs.
1655 (size
< BYTES_PER_WORD
) ||
1656 (size
> (1 << MAX_OBJ_ORDER
) * PAGE_SIZE
) || (dtor
&& !ctor
)) {
1657 printk(KERN_ERR
"%s: Early error in slab %s\n",
1658 __FUNCTION__
, name
);
1662 mutex_lock(&cache_chain_mutex
);
1664 list_for_each(p
, &cache_chain
) {
1665 struct kmem_cache
*pc
= list_entry(p
, struct kmem_cache
, next
);
1666 mm_segment_t old_fs
= get_fs();
1671 * This happens when the module gets unloaded and doesn't
1672 * destroy its slab cache and no-one else reuses the vmalloc
1673 * area of the module. Print a warning.
1676 res
= __get_user(tmp
, pc
->name
);
1679 printk("SLAB: cache with size %d has lost its name\n",
1684 if (!strcmp(pc
->name
, name
)) {
1685 printk("kmem_cache_create: duplicate cache %s\n", name
);
1692 WARN_ON(strchr(name
, ' ')); /* It confuses parsers */
1693 if ((flags
& SLAB_DEBUG_INITIAL
) && !ctor
) {
1694 /* No constructor, but inital state check requested */
1695 printk(KERN_ERR
"%s: No con, but init state check "
1696 "requested - %s\n", __FUNCTION__
, name
);
1697 flags
&= ~SLAB_DEBUG_INITIAL
;
1701 * Enable redzoning and last user accounting, except for caches with
1702 * large objects, if the increased size would increase the object size
1703 * above the next power of two: caches with object sizes just above a
1704 * power of two have a significant amount of internal fragmentation.
1707 || fls(size
- 1) == fls(size
- 1 + 3 * BYTES_PER_WORD
)))
1708 flags
|= SLAB_RED_ZONE
| SLAB_STORE_USER
;
1709 if (!(flags
& SLAB_DESTROY_BY_RCU
))
1710 flags
|= SLAB_POISON
;
1712 if (flags
& SLAB_DESTROY_BY_RCU
)
1713 BUG_ON(flags
& SLAB_POISON
);
1715 if (flags
& SLAB_DESTROY_BY_RCU
)
1719 * Always checks flags, a caller might be expecting debug
1720 * support which isn't available.
1722 if (flags
& ~CREATE_MASK
)
1725 /* Check that size is in terms of words. This is needed to avoid
1726 * unaligned accesses for some archs when redzoning is used, and makes
1727 * sure any on-slab bufctl's are also correctly aligned.
1729 if (size
& (BYTES_PER_WORD
- 1)) {
1730 size
+= (BYTES_PER_WORD
- 1);
1731 size
&= ~(BYTES_PER_WORD
- 1);
1734 /* calculate out the final buffer alignment: */
1735 /* 1) arch recommendation: can be overridden for debug */
1736 if (flags
& SLAB_HWCACHE_ALIGN
) {
1737 /* Default alignment: as specified by the arch code.
1738 * Except if an object is really small, then squeeze multiple
1739 * objects into one cacheline.
1741 ralign
= cache_line_size();
1742 while (size
<= ralign
/ 2)
1745 ralign
= BYTES_PER_WORD
;
1747 /* 2) arch mandated alignment: disables debug if necessary */
1748 if (ralign
< ARCH_SLAB_MINALIGN
) {
1749 ralign
= ARCH_SLAB_MINALIGN
;
1750 if (ralign
> BYTES_PER_WORD
)
1751 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
1753 /* 3) caller mandated alignment: disables debug if necessary */
1754 if (ralign
< align
) {
1756 if (ralign
> BYTES_PER_WORD
)
1757 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
1759 /* 4) Store it. Note that the debug code below can reduce
1760 * the alignment to BYTES_PER_WORD.
1764 /* Get cache's description obj. */
1765 cachep
= kmem_cache_alloc(&cache_cache
, SLAB_KERNEL
);
1768 memset(cachep
, 0, sizeof(struct kmem_cache
));
1771 cachep
->obj_size
= size
;
1773 if (flags
& SLAB_RED_ZONE
) {
1774 /* redzoning only works with word aligned caches */
1775 align
= BYTES_PER_WORD
;
1777 /* add space for red zone words */
1778 cachep
->obj_offset
+= BYTES_PER_WORD
;
1779 size
+= 2 * BYTES_PER_WORD
;
1781 if (flags
& SLAB_STORE_USER
) {
1782 /* user store requires word alignment and
1783 * one word storage behind the end of the real
1786 align
= BYTES_PER_WORD
;
1787 size
+= BYTES_PER_WORD
;
1789 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
1790 if (size
>= malloc_sizes
[INDEX_L3
+ 1].cs_size
1791 && cachep
->obj_size
> cache_line_size() && size
< PAGE_SIZE
) {
1792 cachep
->obj_offset
+= PAGE_SIZE
- size
;
1798 /* Determine if the slab management is 'on' or 'off' slab. */
1799 if (size
>= (PAGE_SIZE
>> 3))
1801 * Size is large, assume best to place the slab management obj
1802 * off-slab (should allow better packing of objs).
1804 flags
|= CFLGS_OFF_SLAB
;
1806 size
= ALIGN(size
, align
);
1808 if ((flags
& SLAB_RECLAIM_ACCOUNT
) && size
<= PAGE_SIZE
) {
1810 * A VFS-reclaimable slab tends to have most allocations
1811 * as GFP_NOFS and we really don't want to have to be allocating
1812 * higher-order pages when we are unable to shrink dcache.
1814 cachep
->gfporder
= 0;
1815 cache_estimate(cachep
->gfporder
, size
, align
, flags
,
1816 &left_over
, &cachep
->num
);
1818 left_over
= calculate_slab_order(cachep
, size
, align
, flags
);
1821 printk("kmem_cache_create: couldn't create cache %s.\n", name
);
1822 kmem_cache_free(&cache_cache
, cachep
);
1826 slab_size
= ALIGN(cachep
->num
* sizeof(kmem_bufctl_t
)
1827 + sizeof(struct slab
), align
);
1830 * If the slab has been placed off-slab, and we have enough space then
1831 * move it on-slab. This is at the expense of any extra colouring.
1833 if (flags
& CFLGS_OFF_SLAB
&& left_over
>= slab_size
) {
1834 flags
&= ~CFLGS_OFF_SLAB
;
1835 left_over
-= slab_size
;
1838 if (flags
& CFLGS_OFF_SLAB
) {
1839 /* really off slab. No need for manual alignment */
1841 cachep
->num
* sizeof(kmem_bufctl_t
) + sizeof(struct slab
);
1844 cachep
->colour_off
= cache_line_size();
1845 /* Offset must be a multiple of the alignment. */
1846 if (cachep
->colour_off
< align
)
1847 cachep
->colour_off
= align
;
1848 cachep
->colour
= left_over
/ cachep
->colour_off
;
1849 cachep
->slab_size
= slab_size
;
1850 cachep
->flags
= flags
;
1851 cachep
->gfpflags
= 0;
1852 if (flags
& SLAB_CACHE_DMA
)
1853 cachep
->gfpflags
|= GFP_DMA
;
1854 spin_lock_init(&cachep
->spinlock
);
1855 cachep
->buffer_size
= size
;
1857 if (flags
& CFLGS_OFF_SLAB
)
1858 cachep
->slabp_cache
= kmem_find_general_cachep(slab_size
, 0u);
1859 cachep
->ctor
= ctor
;
1860 cachep
->dtor
= dtor
;
1861 cachep
->name
= name
;
1863 /* Don't let CPUs to come and go */
1866 if (g_cpucache_up
== FULL
) {
1867 enable_cpucache(cachep
);
1869 if (g_cpucache_up
== NONE
) {
1870 /* Note: the first kmem_cache_create must create
1871 * the cache that's used by kmalloc(24), otherwise
1872 * the creation of further caches will BUG().
1874 cachep
->array
[smp_processor_id()] =
1875 &initarray_generic
.cache
;
1877 /* If the cache that's used by
1878 * kmalloc(sizeof(kmem_list3)) is the first cache,
1879 * then we need to set up all its list3s, otherwise
1880 * the creation of further caches will BUG().
1882 set_up_list3s(cachep
, SIZE_AC
);
1883 if (INDEX_AC
== INDEX_L3
)
1884 g_cpucache_up
= PARTIAL_L3
;
1886 g_cpucache_up
= PARTIAL_AC
;
1888 cachep
->array
[smp_processor_id()] =
1889 kmalloc(sizeof(struct arraycache_init
), GFP_KERNEL
);
1891 if (g_cpucache_up
== PARTIAL_AC
) {
1892 set_up_list3s(cachep
, SIZE_L3
);
1893 g_cpucache_up
= PARTIAL_L3
;
1896 for_each_online_node(node
) {
1898 cachep
->nodelists
[node
] =
1900 (struct kmem_list3
),
1902 BUG_ON(!cachep
->nodelists
[node
]);
1903 kmem_list3_init(cachep
->
1908 cachep
->nodelists
[numa_node_id()]->next_reap
=
1909 jiffies
+ REAPTIMEOUT_LIST3
+
1910 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
1912 BUG_ON(!cpu_cache_get(cachep
));
1913 cpu_cache_get(cachep
)->avail
= 0;
1914 cpu_cache_get(cachep
)->limit
= BOOT_CPUCACHE_ENTRIES
;
1915 cpu_cache_get(cachep
)->batchcount
= 1;
1916 cpu_cache_get(cachep
)->touched
= 0;
1917 cachep
->batchcount
= 1;
1918 cachep
->limit
= BOOT_CPUCACHE_ENTRIES
;
1921 /* cache setup completed, link it into the list */
1922 list_add(&cachep
->next
, &cache_chain
);
1923 unlock_cpu_hotplug();
1925 if (!cachep
&& (flags
& SLAB_PANIC
))
1926 panic("kmem_cache_create(): failed to create slab `%s'\n",
1928 mutex_unlock(&cache_chain_mutex
);
1931 EXPORT_SYMBOL(kmem_cache_create
);
1934 static void check_irq_off(void)
1936 BUG_ON(!irqs_disabled());
1939 static void check_irq_on(void)
1941 BUG_ON(irqs_disabled());
1944 static void check_spinlock_acquired(struct kmem_cache
*cachep
)
1948 assert_spin_locked(&cachep
->nodelists
[numa_node_id()]->list_lock
);
1952 static void check_spinlock_acquired_node(struct kmem_cache
*cachep
, int node
)
1956 assert_spin_locked(&cachep
->nodelists
[node
]->list_lock
);
1961 #define check_irq_off() do { } while(0)
1962 #define check_irq_on() do { } while(0)
1963 #define check_spinlock_acquired(x) do { } while(0)
1964 #define check_spinlock_acquired_node(x, y) do { } while(0)
1968 * Waits for all CPUs to execute func().
1970 static void smp_call_function_all_cpus(void (*func
)(void *arg
), void *arg
)
1975 local_irq_disable();
1979 if (smp_call_function(func
, arg
, 1, 1))
1985 static void drain_array_locked(struct kmem_cache
*cachep
, struct array_cache
*ac
,
1986 int force
, int node
);
1988 static void do_drain(void *arg
)
1990 struct kmem_cache
*cachep
= (struct kmem_cache
*) arg
;
1991 struct array_cache
*ac
;
1992 int node
= numa_node_id();
1995 ac
= cpu_cache_get(cachep
);
1996 spin_lock(&cachep
->nodelists
[node
]->list_lock
);
1997 free_block(cachep
, ac
->entry
, ac
->avail
, node
);
1998 spin_unlock(&cachep
->nodelists
[node
]->list_lock
);
2002 static void drain_cpu_caches(struct kmem_cache
*cachep
)
2004 struct kmem_list3
*l3
;
2007 smp_call_function_all_cpus(do_drain
, cachep
);
2009 spin_lock_irq(&cachep
->spinlock
);
2010 for_each_online_node(node
) {
2011 l3
= cachep
->nodelists
[node
];
2013 spin_lock(&l3
->list_lock
);
2014 drain_array_locked(cachep
, l3
->shared
, 1, node
);
2015 spin_unlock(&l3
->list_lock
);
2017 drain_alien_cache(cachep
, l3
);
2020 spin_unlock_irq(&cachep
->spinlock
);
2023 static int __node_shrink(struct kmem_cache
*cachep
, int node
)
2026 struct kmem_list3
*l3
= cachep
->nodelists
[node
];
2030 struct list_head
*p
;
2032 p
= l3
->slabs_free
.prev
;
2033 if (p
== &l3
->slabs_free
)
2036 slabp
= list_entry(l3
->slabs_free
.prev
, struct slab
, list
);
2041 list_del(&slabp
->list
);
2043 l3
->free_objects
-= cachep
->num
;
2044 spin_unlock_irq(&l3
->list_lock
);
2045 slab_destroy(cachep
, slabp
);
2046 spin_lock_irq(&l3
->list_lock
);
2048 ret
= !list_empty(&l3
->slabs_full
) || !list_empty(&l3
->slabs_partial
);
2052 static int __cache_shrink(struct kmem_cache
*cachep
)
2055 struct kmem_list3
*l3
;
2057 drain_cpu_caches(cachep
);
2060 for_each_online_node(i
) {
2061 l3
= cachep
->nodelists
[i
];
2063 spin_lock_irq(&l3
->list_lock
);
2064 ret
+= __node_shrink(cachep
, i
);
2065 spin_unlock_irq(&l3
->list_lock
);
2068 return (ret
? 1 : 0);
2072 * kmem_cache_shrink - Shrink a cache.
2073 * @cachep: The cache to shrink.
2075 * Releases as many slabs as possible for a cache.
2076 * To help debugging, a zero exit status indicates all slabs were released.
2078 int kmem_cache_shrink(struct kmem_cache
*cachep
)
2080 if (!cachep
|| in_interrupt())
2083 return __cache_shrink(cachep
);
2085 EXPORT_SYMBOL(kmem_cache_shrink
);
2088 * kmem_cache_destroy - delete a cache
2089 * @cachep: the cache to destroy
2091 * Remove a struct kmem_cache object from the slab cache.
2092 * Returns 0 on success.
2094 * It is expected this function will be called by a module when it is
2095 * unloaded. This will remove the cache completely, and avoid a duplicate
2096 * cache being allocated each time a module is loaded and unloaded, if the
2097 * module doesn't have persistent in-kernel storage across loads and unloads.
2099 * The cache must be empty before calling this function.
2101 * The caller must guarantee that noone will allocate memory from the cache
2102 * during the kmem_cache_destroy().
2104 int kmem_cache_destroy(struct kmem_cache
*cachep
)
2107 struct kmem_list3
*l3
;
2109 if (!cachep
|| in_interrupt())
2112 /* Don't let CPUs to come and go */
2115 /* Find the cache in the chain of caches. */
2116 mutex_lock(&cache_chain_mutex
);
2118 * the chain is never empty, cache_cache is never destroyed
2120 list_del(&cachep
->next
);
2121 mutex_unlock(&cache_chain_mutex
);
2123 if (__cache_shrink(cachep
)) {
2124 slab_error(cachep
, "Can't free all objects");
2125 mutex_lock(&cache_chain_mutex
);
2126 list_add(&cachep
->next
, &cache_chain
);
2127 mutex_unlock(&cache_chain_mutex
);
2128 unlock_cpu_hotplug();
2132 if (unlikely(cachep
->flags
& SLAB_DESTROY_BY_RCU
))
2135 for_each_online_cpu(i
)
2136 kfree(cachep
->array
[i
]);
2138 /* NUMA: free the list3 structures */
2139 for_each_online_node(i
) {
2140 if ((l3
= cachep
->nodelists
[i
])) {
2142 free_alien_cache(l3
->alien
);
2146 kmem_cache_free(&cache_cache
, cachep
);
2148 unlock_cpu_hotplug();
2152 EXPORT_SYMBOL(kmem_cache_destroy
);
2154 /* Get the memory for a slab management obj. */
2155 static struct slab
*alloc_slabmgmt(struct kmem_cache
*cachep
, void *objp
,
2156 int colour_off
, gfp_t local_flags
)
2160 if (OFF_SLAB(cachep
)) {
2161 /* Slab management obj is off-slab. */
2162 slabp
= kmem_cache_alloc(cachep
->slabp_cache
, local_flags
);
2166 slabp
= objp
+ colour_off
;
2167 colour_off
+= cachep
->slab_size
;
2170 slabp
->colouroff
= colour_off
;
2171 slabp
->s_mem
= objp
+ colour_off
;
2176 static inline kmem_bufctl_t
*slab_bufctl(struct slab
*slabp
)
2178 return (kmem_bufctl_t
*) (slabp
+ 1);
2181 static void cache_init_objs(struct kmem_cache
*cachep
,
2182 struct slab
*slabp
, unsigned long ctor_flags
)
2186 for (i
= 0; i
< cachep
->num
; i
++) {
2187 void *objp
= slabp
->s_mem
+ cachep
->buffer_size
* i
;
2189 /* need to poison the objs? */
2190 if (cachep
->flags
& SLAB_POISON
)
2191 poison_obj(cachep
, objp
, POISON_FREE
);
2192 if (cachep
->flags
& SLAB_STORE_USER
)
2193 *dbg_userword(cachep
, objp
) = NULL
;
2195 if (cachep
->flags
& SLAB_RED_ZONE
) {
2196 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2197 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2200 * Constructors are not allowed to allocate memory from
2201 * the same cache which they are a constructor for.
2202 * Otherwise, deadlock. They must also be threaded.
2204 if (cachep
->ctor
&& !(cachep
->flags
& SLAB_POISON
))
2205 cachep
->ctor(objp
+ obj_offset(cachep
), cachep
,
2208 if (cachep
->flags
& SLAB_RED_ZONE
) {
2209 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
2210 slab_error(cachep
, "constructor overwrote the"
2211 " end of an object");
2212 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
2213 slab_error(cachep
, "constructor overwrote the"
2214 " start of an object");
2216 if ((cachep
->buffer_size
% PAGE_SIZE
) == 0 && OFF_SLAB(cachep
)
2217 && cachep
->flags
& SLAB_POISON
)
2218 kernel_map_pages(virt_to_page(objp
),
2219 cachep
->buffer_size
/ PAGE_SIZE
, 0);
2222 cachep
->ctor(objp
, cachep
, ctor_flags
);
2224 slab_bufctl(slabp
)[i
] = i
+ 1;
2226 slab_bufctl(slabp
)[i
- 1] = BUFCTL_END
;
2230 static void kmem_flagcheck(struct kmem_cache
*cachep
, gfp_t flags
)
2232 if (flags
& SLAB_DMA
) {
2233 if (!(cachep
->gfpflags
& GFP_DMA
))
2236 if (cachep
->gfpflags
& GFP_DMA
)
2241 static void *slab_get_obj(struct kmem_cache
*cachep
, struct slab
*slabp
, int nodeid
)
2243 void *objp
= slabp
->s_mem
+ (slabp
->free
* cachep
->buffer_size
);
2247 next
= slab_bufctl(slabp
)[slabp
->free
];
2249 slab_bufctl(slabp
)[slabp
->free
] = BUFCTL_FREE
;
2250 WARN_ON(slabp
->nodeid
!= nodeid
);
2257 static void slab_put_obj(struct kmem_cache
*cachep
, struct slab
*slabp
, void *objp
,
2260 unsigned int objnr
= (unsigned)(objp
-slabp
->s_mem
) / cachep
->buffer_size
;
2263 /* Verify that the slab belongs to the intended node */
2264 WARN_ON(slabp
->nodeid
!= nodeid
);
2266 if (slab_bufctl(slabp
)[objnr
] != BUFCTL_FREE
) {
2267 printk(KERN_ERR
"slab: double free detected in cache "
2268 "'%s', objp %p\n", cachep
->name
, objp
);
2272 slab_bufctl(slabp
)[objnr
] = slabp
->free
;
2273 slabp
->free
= objnr
;
2277 static void set_slab_attr(struct kmem_cache
*cachep
, struct slab
*slabp
, void *objp
)
2282 /* Nasty!!!!!! I hope this is OK. */
2283 i
= 1 << cachep
->gfporder
;
2284 page
= virt_to_page(objp
);
2286 page_set_cache(page
, cachep
);
2287 page_set_slab(page
, slabp
);
2293 * Grow (by 1) the number of slabs within a cache. This is called by
2294 * kmem_cache_alloc() when there are no active objs left in a cache.
2296 static int cache_grow(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
2302 unsigned long ctor_flags
;
2303 struct kmem_list3
*l3
;
2305 /* Be lazy and only check for valid flags here,
2306 * keeping it out of the critical path in kmem_cache_alloc().
2308 if (flags
& ~(SLAB_DMA
| SLAB_LEVEL_MASK
| SLAB_NO_GROW
))
2310 if (flags
& SLAB_NO_GROW
)
2313 ctor_flags
= SLAB_CTOR_CONSTRUCTOR
;
2314 local_flags
= (flags
& SLAB_LEVEL_MASK
);
2315 if (!(local_flags
& __GFP_WAIT
))
2317 * Not allowed to sleep. Need to tell a constructor about
2318 * this - it might need to know...
2320 ctor_flags
|= SLAB_CTOR_ATOMIC
;
2322 /* About to mess with non-constant members - lock. */
2324 spin_lock(&cachep
->spinlock
);
2326 /* Get colour for the slab, and cal the next value. */
2327 offset
= cachep
->colour_next
;
2328 cachep
->colour_next
++;
2329 if (cachep
->colour_next
>= cachep
->colour
)
2330 cachep
->colour_next
= 0;
2331 offset
*= cachep
->colour_off
;
2333 spin_unlock(&cachep
->spinlock
);
2336 if (local_flags
& __GFP_WAIT
)
2340 * The test for missing atomic flag is performed here, rather than
2341 * the more obvious place, simply to reduce the critical path length
2342 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2343 * will eventually be caught here (where it matters).
2345 kmem_flagcheck(cachep
, flags
);
2347 /* Get mem for the objs.
2348 * Attempt to allocate a physical page from 'nodeid',
2350 if (!(objp
= kmem_getpages(cachep
, flags
, nodeid
)))
2353 /* Get slab management. */
2354 if (!(slabp
= alloc_slabmgmt(cachep
, objp
, offset
, local_flags
)))
2357 slabp
->nodeid
= nodeid
;
2358 set_slab_attr(cachep
, slabp
, objp
);
2360 cache_init_objs(cachep
, slabp
, ctor_flags
);
2362 if (local_flags
& __GFP_WAIT
)
2363 local_irq_disable();
2365 l3
= cachep
->nodelists
[nodeid
];
2366 spin_lock(&l3
->list_lock
);
2368 /* Make slab active. */
2369 list_add_tail(&slabp
->list
, &(l3
->slabs_free
));
2370 STATS_INC_GROWN(cachep
);
2371 l3
->free_objects
+= cachep
->num
;
2372 spin_unlock(&l3
->list_lock
);
2375 kmem_freepages(cachep
, objp
);
2377 if (local_flags
& __GFP_WAIT
)
2378 local_irq_disable();
2385 * Perform extra freeing checks:
2386 * - detect bad pointers.
2387 * - POISON/RED_ZONE checking
2388 * - destructor calls, for caches with POISON+dtor
2390 static void kfree_debugcheck(const void *objp
)
2394 if (!virt_addr_valid(objp
)) {
2395 printk(KERN_ERR
"kfree_debugcheck: out of range ptr %lxh.\n",
2396 (unsigned long)objp
);
2399 page
= virt_to_page(objp
);
2400 if (!PageSlab(page
)) {
2401 printk(KERN_ERR
"kfree_debugcheck: bad ptr %lxh.\n",
2402 (unsigned long)objp
);
2407 static void *cache_free_debugcheck(struct kmem_cache
*cachep
, void *objp
,
2414 objp
-= obj_offset(cachep
);
2415 kfree_debugcheck(objp
);
2416 page
= virt_to_page(objp
);
2418 if (page_get_cache(page
) != cachep
) {
2420 "mismatch in kmem_cache_free: expected cache %p, got %p\n",
2421 page_get_cache(page
), cachep
);
2422 printk(KERN_ERR
"%p is %s.\n", cachep
, cachep
->name
);
2423 printk(KERN_ERR
"%p is %s.\n", page_get_cache(page
),
2424 page_get_cache(page
)->name
);
2427 slabp
= page_get_slab(page
);
2429 if (cachep
->flags
& SLAB_RED_ZONE
) {
2430 if (*dbg_redzone1(cachep
, objp
) != RED_ACTIVE
2431 || *dbg_redzone2(cachep
, objp
) != RED_ACTIVE
) {
2433 "double free, or memory outside"
2434 " object was overwritten");
2436 "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n",
2437 objp
, *dbg_redzone1(cachep
, objp
),
2438 *dbg_redzone2(cachep
, objp
));
2440 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2441 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2443 if (cachep
->flags
& SLAB_STORE_USER
)
2444 *dbg_userword(cachep
, objp
) = caller
;
2446 objnr
= (unsigned)(objp
- slabp
->s_mem
) / cachep
->buffer_size
;
2448 BUG_ON(objnr
>= cachep
->num
);
2449 BUG_ON(objp
!= slabp
->s_mem
+ objnr
* cachep
->buffer_size
);
2451 if (cachep
->flags
& SLAB_DEBUG_INITIAL
) {
2452 /* Need to call the slab's constructor so the
2453 * caller can perform a verify of its state (debugging).
2454 * Called without the cache-lock held.
2456 cachep
->ctor(objp
+ obj_offset(cachep
),
2457 cachep
, SLAB_CTOR_CONSTRUCTOR
| SLAB_CTOR_VERIFY
);
2459 if (cachep
->flags
& SLAB_POISON
&& cachep
->dtor
) {
2460 /* we want to cache poison the object,
2461 * call the destruction callback
2463 cachep
->dtor(objp
+ obj_offset(cachep
), cachep
, 0);
2465 if (cachep
->flags
& SLAB_POISON
) {
2466 #ifdef CONFIG_DEBUG_PAGEALLOC
2467 if ((cachep
->buffer_size
% PAGE_SIZE
) == 0 && OFF_SLAB(cachep
)) {
2468 store_stackinfo(cachep
, objp
, (unsigned long)caller
);
2469 kernel_map_pages(virt_to_page(objp
),
2470 cachep
->buffer_size
/ PAGE_SIZE
, 0);
2472 poison_obj(cachep
, objp
, POISON_FREE
);
2475 poison_obj(cachep
, objp
, POISON_FREE
);
2481 static void check_slabp(struct kmem_cache
*cachep
, struct slab
*slabp
)
2486 /* Check slab's freelist to see if this obj is there. */
2487 for (i
= slabp
->free
; i
!= BUFCTL_END
; i
= slab_bufctl(slabp
)[i
]) {
2489 if (entries
> cachep
->num
|| i
>= cachep
->num
)
2492 if (entries
!= cachep
->num
- slabp
->inuse
) {
2495 "slab: Internal list corruption detected in cache '%s'(%d), slabp %p(%d). Hexdump:\n",
2496 cachep
->name
, cachep
->num
, slabp
, slabp
->inuse
);
2498 i
< sizeof(slabp
) + cachep
->num
* sizeof(kmem_bufctl_t
);
2501 printk("\n%03x:", i
);
2502 printk(" %02x", ((unsigned char *)slabp
)[i
]);
2509 #define kfree_debugcheck(x) do { } while(0)
2510 #define cache_free_debugcheck(x,objp,z) (objp)
2511 #define check_slabp(x,y) do { } while(0)
2514 static void *cache_alloc_refill(struct kmem_cache
*cachep
, gfp_t flags
)
2517 struct kmem_list3
*l3
;
2518 struct array_cache
*ac
;
2521 ac
= cpu_cache_get(cachep
);
2523 batchcount
= ac
->batchcount
;
2524 if (!ac
->touched
&& batchcount
> BATCHREFILL_LIMIT
) {
2525 /* if there was little recent activity on this
2526 * cache, then perform only a partial refill.
2527 * Otherwise we could generate refill bouncing.
2529 batchcount
= BATCHREFILL_LIMIT
;
2531 l3
= cachep
->nodelists
[numa_node_id()];
2533 BUG_ON(ac
->avail
> 0 || !l3
);
2534 spin_lock(&l3
->list_lock
);
2537 struct array_cache
*shared_array
= l3
->shared
;
2538 if (shared_array
->avail
) {
2539 if (batchcount
> shared_array
->avail
)
2540 batchcount
= shared_array
->avail
;
2541 shared_array
->avail
-= batchcount
;
2542 ac
->avail
= batchcount
;
2544 &(shared_array
->entry
[shared_array
->avail
]),
2545 sizeof(void *) * batchcount
);
2546 shared_array
->touched
= 1;
2550 while (batchcount
> 0) {
2551 struct list_head
*entry
;
2553 /* Get slab alloc is to come from. */
2554 entry
= l3
->slabs_partial
.next
;
2555 if (entry
== &l3
->slabs_partial
) {
2556 l3
->free_touched
= 1;
2557 entry
= l3
->slabs_free
.next
;
2558 if (entry
== &l3
->slabs_free
)
2562 slabp
= list_entry(entry
, struct slab
, list
);
2563 check_slabp(cachep
, slabp
);
2564 check_spinlock_acquired(cachep
);
2565 while (slabp
->inuse
< cachep
->num
&& batchcount
--) {
2566 STATS_INC_ALLOCED(cachep
);
2567 STATS_INC_ACTIVE(cachep
);
2568 STATS_SET_HIGH(cachep
);
2570 ac
->entry
[ac
->avail
++] = slab_get_obj(cachep
, slabp
,
2573 check_slabp(cachep
, slabp
);
2575 /* move slabp to correct slabp list: */
2576 list_del(&slabp
->list
);
2577 if (slabp
->free
== BUFCTL_END
)
2578 list_add(&slabp
->list
, &l3
->slabs_full
);
2580 list_add(&slabp
->list
, &l3
->slabs_partial
);
2584 l3
->free_objects
-= ac
->avail
;
2586 spin_unlock(&l3
->list_lock
);
2588 if (unlikely(!ac
->avail
)) {
2590 x
= cache_grow(cachep
, flags
, numa_node_id());
2592 // cache_grow can reenable interrupts, then ac could change.
2593 ac
= cpu_cache_get(cachep
);
2594 if (!x
&& ac
->avail
== 0) // no objects in sight? abort
2597 if (!ac
->avail
) // objects refilled by interrupt?
2601 return ac
->entry
[--ac
->avail
];
2605 cache_alloc_debugcheck_before(struct kmem_cache
*cachep
, gfp_t flags
)
2607 might_sleep_if(flags
& __GFP_WAIT
);
2609 kmem_flagcheck(cachep
, flags
);
2614 static void *cache_alloc_debugcheck_after(struct kmem_cache
*cachep
, gfp_t flags
,
2615 void *objp
, void *caller
)
2619 if (cachep
->flags
& SLAB_POISON
) {
2620 #ifdef CONFIG_DEBUG_PAGEALLOC
2621 if ((cachep
->buffer_size
% PAGE_SIZE
) == 0 && OFF_SLAB(cachep
))
2622 kernel_map_pages(virt_to_page(objp
),
2623 cachep
->buffer_size
/ PAGE_SIZE
, 1);
2625 check_poison_obj(cachep
, objp
);
2627 check_poison_obj(cachep
, objp
);
2629 poison_obj(cachep
, objp
, POISON_INUSE
);
2631 if (cachep
->flags
& SLAB_STORE_USER
)
2632 *dbg_userword(cachep
, objp
) = caller
;
2634 if (cachep
->flags
& SLAB_RED_ZONE
) {
2635 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
2636 || *dbg_redzone2(cachep
, objp
) != RED_INACTIVE
) {
2638 "double free, or memory outside"
2639 " object was overwritten");
2641 "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n",
2642 objp
, *dbg_redzone1(cachep
, objp
),
2643 *dbg_redzone2(cachep
, objp
));
2645 *dbg_redzone1(cachep
, objp
) = RED_ACTIVE
;
2646 *dbg_redzone2(cachep
, objp
) = RED_ACTIVE
;
2648 objp
+= obj_offset(cachep
);
2649 if (cachep
->ctor
&& cachep
->flags
& SLAB_POISON
) {
2650 unsigned long ctor_flags
= SLAB_CTOR_CONSTRUCTOR
;
2652 if (!(flags
& __GFP_WAIT
))
2653 ctor_flags
|= SLAB_CTOR_ATOMIC
;
2655 cachep
->ctor(objp
, cachep
, ctor_flags
);
2660 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
2663 static inline void *____cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
2666 struct array_cache
*ac
;
2669 if (unlikely(current
->mempolicy
&& !in_interrupt())) {
2670 int nid
= slab_node(current
->mempolicy
);
2672 if (nid
!= numa_node_id())
2673 return __cache_alloc_node(cachep
, flags
, nid
);
2678 ac
= cpu_cache_get(cachep
);
2679 if (likely(ac
->avail
)) {
2680 STATS_INC_ALLOCHIT(cachep
);
2682 objp
= ac
->entry
[--ac
->avail
];
2684 STATS_INC_ALLOCMISS(cachep
);
2685 objp
= cache_alloc_refill(cachep
, flags
);
2690 static __always_inline
void *
2691 __cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
, void *caller
)
2693 unsigned long save_flags
;
2696 cache_alloc_debugcheck_before(cachep
, flags
);
2698 local_irq_save(save_flags
);
2699 objp
= ____cache_alloc(cachep
, flags
);
2700 local_irq_restore(save_flags
);
2701 objp
= cache_alloc_debugcheck_after(cachep
, flags
, objp
,
2709 * A interface to enable slab creation on nodeid
2711 static void *__cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
2713 struct list_head
*entry
;
2715 struct kmem_list3
*l3
;
2719 l3
= cachep
->nodelists
[nodeid
];
2723 spin_lock(&l3
->list_lock
);
2724 entry
= l3
->slabs_partial
.next
;
2725 if (entry
== &l3
->slabs_partial
) {
2726 l3
->free_touched
= 1;
2727 entry
= l3
->slabs_free
.next
;
2728 if (entry
== &l3
->slabs_free
)
2732 slabp
= list_entry(entry
, struct slab
, list
);
2733 check_spinlock_acquired_node(cachep
, nodeid
);
2734 check_slabp(cachep
, slabp
);
2736 STATS_INC_NODEALLOCS(cachep
);
2737 STATS_INC_ACTIVE(cachep
);
2738 STATS_SET_HIGH(cachep
);
2740 BUG_ON(slabp
->inuse
== cachep
->num
);
2742 obj
= slab_get_obj(cachep
, slabp
, nodeid
);
2743 check_slabp(cachep
, slabp
);
2745 /* move slabp to correct slabp list: */
2746 list_del(&slabp
->list
);
2748 if (slabp
->free
== BUFCTL_END
) {
2749 list_add(&slabp
->list
, &l3
->slabs_full
);
2751 list_add(&slabp
->list
, &l3
->slabs_partial
);
2754 spin_unlock(&l3
->list_lock
);
2758 spin_unlock(&l3
->list_lock
);
2759 x
= cache_grow(cachep
, flags
, nodeid
);
2771 * Caller needs to acquire correct kmem_list's list_lock
2773 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int nr_objects
,
2777 struct kmem_list3
*l3
;
2779 for (i
= 0; i
< nr_objects
; i
++) {
2780 void *objp
= objpp
[i
];
2783 slabp
= virt_to_slab(objp
);
2784 l3
= cachep
->nodelists
[node
];
2785 list_del(&slabp
->list
);
2786 check_spinlock_acquired_node(cachep
, node
);
2787 check_slabp(cachep
, slabp
);
2788 slab_put_obj(cachep
, slabp
, objp
, node
);
2789 STATS_DEC_ACTIVE(cachep
);
2791 check_slabp(cachep
, slabp
);
2793 /* fixup slab chains */
2794 if (slabp
->inuse
== 0) {
2795 if (l3
->free_objects
> l3
->free_limit
) {
2796 l3
->free_objects
-= cachep
->num
;
2797 slab_destroy(cachep
, slabp
);
2799 list_add(&slabp
->list
, &l3
->slabs_free
);
2802 /* Unconditionally move a slab to the end of the
2803 * partial list on free - maximum time for the
2804 * other objects to be freed, too.
2806 list_add_tail(&slabp
->list
, &l3
->slabs_partial
);
2811 static void cache_flusharray(struct kmem_cache
*cachep
, struct array_cache
*ac
)
2814 struct kmem_list3
*l3
;
2815 int node
= numa_node_id();
2817 batchcount
= ac
->batchcount
;
2819 BUG_ON(!batchcount
|| batchcount
> ac
->avail
);
2822 l3
= cachep
->nodelists
[node
];
2823 spin_lock(&l3
->list_lock
);
2825 struct array_cache
*shared_array
= l3
->shared
;
2826 int max
= shared_array
->limit
- shared_array
->avail
;
2828 if (batchcount
> max
)
2830 memcpy(&(shared_array
->entry
[shared_array
->avail
]),
2831 ac
->entry
, sizeof(void *) * batchcount
);
2832 shared_array
->avail
+= batchcount
;
2837 free_block(cachep
, ac
->entry
, batchcount
, node
);
2842 struct list_head
*p
;
2844 p
= l3
->slabs_free
.next
;
2845 while (p
!= &(l3
->slabs_free
)) {
2848 slabp
= list_entry(p
, struct slab
, list
);
2849 BUG_ON(slabp
->inuse
);
2854 STATS_SET_FREEABLE(cachep
, i
);
2857 spin_unlock(&l3
->list_lock
);
2858 ac
->avail
-= batchcount
;
2859 memmove(ac
->entry
, &(ac
->entry
[batchcount
]),
2860 sizeof(void *) * ac
->avail
);
2865 * Release an obj back to its cache. If the obj has a constructed
2866 * state, it must be in this state _before_ it is released.
2868 * Called with disabled ints.
2870 static inline void __cache_free(struct kmem_cache
*cachep
, void *objp
)
2872 struct array_cache
*ac
= cpu_cache_get(cachep
);
2875 objp
= cache_free_debugcheck(cachep
, objp
, __builtin_return_address(0));
2877 /* Make sure we are not freeing a object from another
2878 * node to the array cache on this cpu.
2883 slabp
= virt_to_slab(objp
);
2884 if (unlikely(slabp
->nodeid
!= numa_node_id())) {
2885 struct array_cache
*alien
= NULL
;
2886 int nodeid
= slabp
->nodeid
;
2887 struct kmem_list3
*l3
=
2888 cachep
->nodelists
[numa_node_id()];
2890 STATS_INC_NODEFREES(cachep
);
2891 if (l3
->alien
&& l3
->alien
[nodeid
]) {
2892 alien
= l3
->alien
[nodeid
];
2893 spin_lock(&alien
->lock
);
2894 if (unlikely(alien
->avail
== alien
->limit
))
2895 __drain_alien_cache(cachep
,
2897 alien
->entry
[alien
->avail
++] = objp
;
2898 spin_unlock(&alien
->lock
);
2900 spin_lock(&(cachep
->nodelists
[nodeid
])->
2902 free_block(cachep
, &objp
, 1, nodeid
);
2903 spin_unlock(&(cachep
->nodelists
[nodeid
])->
2910 if (likely(ac
->avail
< ac
->limit
)) {
2911 STATS_INC_FREEHIT(cachep
);
2912 ac
->entry
[ac
->avail
++] = objp
;
2915 STATS_INC_FREEMISS(cachep
);
2916 cache_flusharray(cachep
, ac
);
2917 ac
->entry
[ac
->avail
++] = objp
;
2922 * kmem_cache_alloc - Allocate an object
2923 * @cachep: The cache to allocate from.
2924 * @flags: See kmalloc().
2926 * Allocate an object from this cache. The flags are only relevant
2927 * if the cache has no available objects.
2929 void *kmem_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
2931 return __cache_alloc(cachep
, flags
, __builtin_return_address(0));
2933 EXPORT_SYMBOL(kmem_cache_alloc
);
2936 * kmem_ptr_validate - check if an untrusted pointer might
2938 * @cachep: the cache we're checking against
2939 * @ptr: pointer to validate
2941 * This verifies that the untrusted pointer looks sane:
2942 * it is _not_ a guarantee that the pointer is actually
2943 * part of the slab cache in question, but it at least
2944 * validates that the pointer can be dereferenced and
2945 * looks half-way sane.
2947 * Currently only used for dentry validation.
2949 int fastcall
kmem_ptr_validate(struct kmem_cache
*cachep
, void *ptr
)
2951 unsigned long addr
= (unsigned long)ptr
;
2952 unsigned long min_addr
= PAGE_OFFSET
;
2953 unsigned long align_mask
= BYTES_PER_WORD
- 1;
2954 unsigned long size
= cachep
->buffer_size
;
2957 if (unlikely(addr
< min_addr
))
2959 if (unlikely(addr
> (unsigned long)high_memory
- size
))
2961 if (unlikely(addr
& align_mask
))
2963 if (unlikely(!kern_addr_valid(addr
)))
2965 if (unlikely(!kern_addr_valid(addr
+ size
- 1)))
2967 page
= virt_to_page(ptr
);
2968 if (unlikely(!PageSlab(page
)))
2970 if (unlikely(page_get_cache(page
) != cachep
))
2979 * kmem_cache_alloc_node - Allocate an object on the specified node
2980 * @cachep: The cache to allocate from.
2981 * @flags: See kmalloc().
2982 * @nodeid: node number of the target node.
2984 * Identical to kmem_cache_alloc, except that this function is slow
2985 * and can sleep. And it will allocate memory on the given node, which
2986 * can improve the performance for cpu bound structures.
2987 * New and improved: it will now make sure that the object gets
2988 * put on the correct node list so that there is no false sharing.
2990 void *kmem_cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
2992 unsigned long save_flags
;
2995 cache_alloc_debugcheck_before(cachep
, flags
);
2996 local_irq_save(save_flags
);
2998 if (nodeid
== -1 || nodeid
== numa_node_id() ||
2999 !cachep
->nodelists
[nodeid
])
3000 ptr
= ____cache_alloc(cachep
, flags
);
3002 ptr
= __cache_alloc_node(cachep
, flags
, nodeid
);
3003 local_irq_restore(save_flags
);
3005 ptr
= cache_alloc_debugcheck_after(cachep
, flags
, ptr
,
3006 __builtin_return_address(0));
3010 EXPORT_SYMBOL(kmem_cache_alloc_node
);
3012 void *kmalloc_node(size_t size
, gfp_t flags
, int node
)
3014 struct kmem_cache
*cachep
;
3016 cachep
= kmem_find_general_cachep(size
, flags
);
3017 if (unlikely(cachep
== NULL
))
3019 return kmem_cache_alloc_node(cachep
, flags
, node
);
3021 EXPORT_SYMBOL(kmalloc_node
);
3025 * kmalloc - allocate memory
3026 * @size: how many bytes of memory are required.
3027 * @flags: the type of memory to allocate.
3029 * kmalloc is the normal method of allocating memory
3032 * The @flags argument may be one of:
3034 * %GFP_USER - Allocate memory on behalf of user. May sleep.
3036 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
3038 * %GFP_ATOMIC - Allocation will not sleep. Use inside interrupt handlers.
3040 * Additionally, the %GFP_DMA flag may be set to indicate the memory
3041 * must be suitable for DMA. This can mean different things on different
3042 * platforms. For example, on i386, it means that the memory must come
3043 * from the first 16MB.
3045 static __always_inline
void *__do_kmalloc(size_t size
, gfp_t flags
,
3048 struct kmem_cache
*cachep
;
3050 /* If you want to save a few bytes .text space: replace
3052 * Then kmalloc uses the uninlined functions instead of the inline
3055 cachep
= __find_general_cachep(size
, flags
);
3056 if (unlikely(cachep
== NULL
))
3058 return __cache_alloc(cachep
, flags
, caller
);
3061 #ifndef CONFIG_DEBUG_SLAB
3063 void *__kmalloc(size_t size
, gfp_t flags
)
3065 return __do_kmalloc(size
, flags
, NULL
);
3067 EXPORT_SYMBOL(__kmalloc
);
3071 void *__kmalloc_track_caller(size_t size
, gfp_t flags
, void *caller
)
3073 return __do_kmalloc(size
, flags
, caller
);
3075 EXPORT_SYMBOL(__kmalloc_track_caller
);
3081 * __alloc_percpu - allocate one copy of the object for every present
3082 * cpu in the system, zeroing them.
3083 * Objects should be dereferenced using the per_cpu_ptr macro only.
3085 * @size: how many bytes of memory are required.
3087 void *__alloc_percpu(size_t size
)
3090 struct percpu_data
*pdata
= kmalloc(sizeof(*pdata
), GFP_KERNEL
);
3096 * Cannot use for_each_online_cpu since a cpu may come online
3097 * and we have no way of figuring out how to fix the array
3098 * that we have allocated then....
3101 int node
= cpu_to_node(i
);
3103 if (node_online(node
))
3104 pdata
->ptrs
[i
] = kmalloc_node(size
, GFP_KERNEL
, node
);
3106 pdata
->ptrs
[i
] = kmalloc(size
, GFP_KERNEL
);
3108 if (!pdata
->ptrs
[i
])
3110 memset(pdata
->ptrs
[i
], 0, size
);
3113 /* Catch derefs w/o wrappers */
3114 return (void *)(~(unsigned long)pdata
);
3118 if (!cpu_possible(i
))
3120 kfree(pdata
->ptrs
[i
]);
3125 EXPORT_SYMBOL(__alloc_percpu
);
3129 * kmem_cache_free - Deallocate an object
3130 * @cachep: The cache the allocation was from.
3131 * @objp: The previously allocated object.
3133 * Free an object which was previously allocated from this
3136 void kmem_cache_free(struct kmem_cache
*cachep
, void *objp
)
3138 unsigned long flags
;
3140 local_irq_save(flags
);
3141 __cache_free(cachep
, objp
);
3142 local_irq_restore(flags
);
3144 EXPORT_SYMBOL(kmem_cache_free
);
3147 * kfree - free previously allocated memory
3148 * @objp: pointer returned by kmalloc.
3150 * If @objp is NULL, no operation is performed.
3152 * Don't free memory not originally allocated by kmalloc()
3153 * or you will run into trouble.
3155 void kfree(const void *objp
)
3157 struct kmem_cache
*c
;
3158 unsigned long flags
;
3160 if (unlikely(!objp
))
3162 local_irq_save(flags
);
3163 kfree_debugcheck(objp
);
3164 c
= virt_to_cache(objp
);
3165 mutex_debug_check_no_locks_freed(objp
, obj_size(c
));
3166 __cache_free(c
, (void *)objp
);
3167 local_irq_restore(flags
);
3169 EXPORT_SYMBOL(kfree
);
3173 * free_percpu - free previously allocated percpu memory
3174 * @objp: pointer returned by alloc_percpu.
3176 * Don't free memory not originally allocated by alloc_percpu()
3177 * The complemented objp is to check for that.
3179 void free_percpu(const void *objp
)
3182 struct percpu_data
*p
= (struct percpu_data
*)(~(unsigned long)objp
);
3185 * We allocate for all cpus so we cannot use for online cpu here.
3191 EXPORT_SYMBOL(free_percpu
);
3194 unsigned int kmem_cache_size(struct kmem_cache
*cachep
)
3196 return obj_size(cachep
);
3198 EXPORT_SYMBOL(kmem_cache_size
);
3200 const char *kmem_cache_name(struct kmem_cache
*cachep
)
3202 return cachep
->name
;
3204 EXPORT_SYMBOL_GPL(kmem_cache_name
);
3207 * This initializes kmem_list3 for all nodes.
3209 static int alloc_kmemlist(struct kmem_cache
*cachep
)
3212 struct kmem_list3
*l3
;
3215 for_each_online_node(node
) {
3216 struct array_cache
*nc
= NULL
, *new;
3217 struct array_cache
**new_alien
= NULL
;
3219 if (!(new_alien
= alloc_alien_cache(node
, cachep
->limit
)))
3222 if (!(new = alloc_arraycache(node
, (cachep
->shared
*
3223 cachep
->batchcount
),
3226 if ((l3
= cachep
->nodelists
[node
])) {
3228 spin_lock_irq(&l3
->list_lock
);
3230 if ((nc
= cachep
->nodelists
[node
]->shared
))
3231 free_block(cachep
, nc
->entry
, nc
->avail
, node
);
3234 if (!cachep
->nodelists
[node
]->alien
) {
3235 l3
->alien
= new_alien
;
3238 l3
->free_limit
= (1 + nr_cpus_node(node
)) *
3239 cachep
->batchcount
+ cachep
->num
;
3240 spin_unlock_irq(&l3
->list_lock
);
3242 free_alien_cache(new_alien
);
3245 if (!(l3
= kmalloc_node(sizeof(struct kmem_list3
),
3249 kmem_list3_init(l3
);
3250 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
+
3251 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
3253 l3
->alien
= new_alien
;
3254 l3
->free_limit
= (1 + nr_cpus_node(node
)) *
3255 cachep
->batchcount
+ cachep
->num
;
3256 cachep
->nodelists
[node
] = l3
;
3264 struct ccupdate_struct
{
3265 struct kmem_cache
*cachep
;
3266 struct array_cache
*new[NR_CPUS
];
3269 static void do_ccupdate_local(void *info
)
3271 struct ccupdate_struct
*new = (struct ccupdate_struct
*)info
;
3272 struct array_cache
*old
;
3275 old
= cpu_cache_get(new->cachep
);
3277 new->cachep
->array
[smp_processor_id()] = new->new[smp_processor_id()];
3278 new->new[smp_processor_id()] = old
;
3281 static int do_tune_cpucache(struct kmem_cache
*cachep
, int limit
, int batchcount
,
3284 struct ccupdate_struct
new;
3287 memset(&new.new, 0, sizeof(new.new));
3288 for_each_online_cpu(i
) {
3290 alloc_arraycache(cpu_to_node(i
), limit
, batchcount
);
3292 for (i
--; i
>= 0; i
--)
3297 new.cachep
= cachep
;
3299 smp_call_function_all_cpus(do_ccupdate_local
, (void *)&new);
3302 spin_lock_irq(&cachep
->spinlock
);
3303 cachep
->batchcount
= batchcount
;
3304 cachep
->limit
= limit
;
3305 cachep
->shared
= shared
;
3306 spin_unlock_irq(&cachep
->spinlock
);
3308 for_each_online_cpu(i
) {
3309 struct array_cache
*ccold
= new.new[i
];
3312 spin_lock_irq(&cachep
->nodelists
[cpu_to_node(i
)]->list_lock
);
3313 free_block(cachep
, ccold
->entry
, ccold
->avail
, cpu_to_node(i
));
3314 spin_unlock_irq(&cachep
->nodelists
[cpu_to_node(i
)]->list_lock
);
3318 err
= alloc_kmemlist(cachep
);
3320 printk(KERN_ERR
"alloc_kmemlist failed for %s, error %d.\n",
3321 cachep
->name
, -err
);
3327 static void enable_cpucache(struct kmem_cache
*cachep
)
3332 /* The head array serves three purposes:
3333 * - create a LIFO ordering, i.e. return objects that are cache-warm
3334 * - reduce the number of spinlock operations.
3335 * - reduce the number of linked list operations on the slab and
3336 * bufctl chains: array operations are cheaper.
3337 * The numbers are guessed, we should auto-tune as described by
3340 if (cachep
->buffer_size
> 131072)
3342 else if (cachep
->buffer_size
> PAGE_SIZE
)
3344 else if (cachep
->buffer_size
> 1024)
3346 else if (cachep
->buffer_size
> 256)
3351 /* Cpu bound tasks (e.g. network routing) can exhibit cpu bound
3352 * allocation behaviour: Most allocs on one cpu, most free operations
3353 * on another cpu. For these cases, an efficient object passing between
3354 * cpus is necessary. This is provided by a shared array. The array
3355 * replaces Bonwick's magazine layer.
3356 * On uniprocessor, it's functionally equivalent (but less efficient)
3357 * to a larger limit. Thus disabled by default.
3361 if (cachep
->buffer_size
<= PAGE_SIZE
)
3366 /* With debugging enabled, large batchcount lead to excessively
3367 * long periods with disabled local interrupts. Limit the
3373 err
= do_tune_cpucache(cachep
, limit
, (limit
+ 1) / 2, shared
);
3375 printk(KERN_ERR
"enable_cpucache failed for %s, error %d.\n",
3376 cachep
->name
, -err
);
3379 static void drain_array_locked(struct kmem_cache
*cachep
, struct array_cache
*ac
,
3380 int force
, int node
)
3384 check_spinlock_acquired_node(cachep
, node
);
3385 if (ac
->touched
&& !force
) {
3387 } else if (ac
->avail
) {
3388 tofree
= force
? ac
->avail
: (ac
->limit
+ 4) / 5;
3389 if (tofree
> ac
->avail
) {
3390 tofree
= (ac
->avail
+ 1) / 2;
3392 free_block(cachep
, ac
->entry
, tofree
, node
);
3393 ac
->avail
-= tofree
;
3394 memmove(ac
->entry
, &(ac
->entry
[tofree
]),
3395 sizeof(void *) * ac
->avail
);
3400 * cache_reap - Reclaim memory from caches.
3401 * @unused: unused parameter
3403 * Called from workqueue/eventd every few seconds.
3405 * - clear the per-cpu caches for this CPU.
3406 * - return freeable pages to the main free memory pool.
3408 * If we cannot acquire the cache chain mutex then just give up - we'll
3409 * try again on the next iteration.
3411 static void cache_reap(void *unused
)
3413 struct list_head
*walk
;
3414 struct kmem_list3
*l3
;
3416 if (!mutex_trylock(&cache_chain_mutex
)) {
3417 /* Give up. Setup the next iteration. */
3418 schedule_delayed_work(&__get_cpu_var(reap_work
),
3423 list_for_each(walk
, &cache_chain
) {
3424 struct kmem_cache
*searchp
;
3425 struct list_head
*p
;
3429 searchp
= list_entry(walk
, struct kmem_cache
, next
);
3431 if (searchp
->flags
& SLAB_NO_REAP
)
3436 l3
= searchp
->nodelists
[numa_node_id()];
3438 drain_alien_cache(searchp
, l3
);
3439 spin_lock_irq(&l3
->list_lock
);
3441 drain_array_locked(searchp
, cpu_cache_get(searchp
), 0,
3444 if (time_after(l3
->next_reap
, jiffies
))
3447 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
;
3450 drain_array_locked(searchp
, l3
->shared
, 0,
3453 if (l3
->free_touched
) {
3454 l3
->free_touched
= 0;
3459 (l3
->free_limit
+ 5 * searchp
->num
-
3460 1) / (5 * searchp
->num
);
3462 p
= l3
->slabs_free
.next
;
3463 if (p
== &(l3
->slabs_free
))
3466 slabp
= list_entry(p
, struct slab
, list
);
3467 BUG_ON(slabp
->inuse
);
3468 list_del(&slabp
->list
);
3469 STATS_INC_REAPED(searchp
);
3471 /* Safe to drop the lock. The slab is no longer
3472 * linked to the cache.
3473 * searchp cannot disappear, we hold
3476 l3
->free_objects
-= searchp
->num
;
3477 spin_unlock_irq(&l3
->list_lock
);
3478 slab_destroy(searchp
, slabp
);
3479 spin_lock_irq(&l3
->list_lock
);
3480 } while (--tofree
> 0);
3482 spin_unlock_irq(&l3
->list_lock
);
3487 mutex_unlock(&cache_chain_mutex
);
3488 drain_remote_pages();
3489 /* Setup the next iteration */
3490 schedule_delayed_work(&__get_cpu_var(reap_work
), REAPTIMEOUT_CPUC
);
3493 #ifdef CONFIG_PROC_FS
3495 static void print_slabinfo_header(struct seq_file
*m
)
3498 * Output format version, so at least we can change it
3499 * without _too_ many complaints.
3502 seq_puts(m
, "slabinfo - version: 2.1 (statistics)\n");
3504 seq_puts(m
, "slabinfo - version: 2.1\n");
3506 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> "
3507 "<objperslab> <pagesperslab>");
3508 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
3509 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
3511 seq_puts(m
, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
3512 "<error> <maxfreeable> <nodeallocs> <remotefrees>");
3513 seq_puts(m
, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
3518 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
3521 struct list_head
*p
;
3523 mutex_lock(&cache_chain_mutex
);
3525 print_slabinfo_header(m
);
3526 p
= cache_chain
.next
;
3529 if (p
== &cache_chain
)
3532 return list_entry(p
, struct kmem_cache
, next
);
3535 static void *s_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
3537 struct kmem_cache
*cachep
= p
;
3539 return cachep
->next
.next
== &cache_chain
? NULL
3540 : list_entry(cachep
->next
.next
, struct kmem_cache
, next
);
3543 static void s_stop(struct seq_file
*m
, void *p
)
3545 mutex_unlock(&cache_chain_mutex
);
3548 static int s_show(struct seq_file
*m
, void *p
)
3550 struct kmem_cache
*cachep
= p
;
3551 struct list_head
*q
;
3553 unsigned long active_objs
;
3554 unsigned long num_objs
;
3555 unsigned long active_slabs
= 0;
3556 unsigned long num_slabs
, free_objects
= 0, shared_avail
= 0;
3560 struct kmem_list3
*l3
;
3563 spin_lock_irq(&cachep
->spinlock
);
3566 for_each_online_node(node
) {
3567 l3
= cachep
->nodelists
[node
];
3571 spin_lock(&l3
->list_lock
);
3573 list_for_each(q
, &l3
->slabs_full
) {
3574 slabp
= list_entry(q
, struct slab
, list
);
3575 if (slabp
->inuse
!= cachep
->num
&& !error
)
3576 error
= "slabs_full accounting error";
3577 active_objs
+= cachep
->num
;
3580 list_for_each(q
, &l3
->slabs_partial
) {
3581 slabp
= list_entry(q
, struct slab
, list
);
3582 if (slabp
->inuse
== cachep
->num
&& !error
)
3583 error
= "slabs_partial inuse accounting error";
3584 if (!slabp
->inuse
&& !error
)
3585 error
= "slabs_partial/inuse accounting error";
3586 active_objs
+= slabp
->inuse
;
3589 list_for_each(q
, &l3
->slabs_free
) {
3590 slabp
= list_entry(q
, struct slab
, list
);
3591 if (slabp
->inuse
&& !error
)
3592 error
= "slabs_free/inuse accounting error";
3595 free_objects
+= l3
->free_objects
;
3596 shared_avail
+= l3
->shared
->avail
;
3598 spin_unlock(&l3
->list_lock
);
3600 num_slabs
+= active_slabs
;
3601 num_objs
= num_slabs
* cachep
->num
;
3602 if (num_objs
- active_objs
!= free_objects
&& !error
)
3603 error
= "free_objects accounting error";
3605 name
= cachep
->name
;
3607 printk(KERN_ERR
"slab: cache %s error: %s\n", name
, error
);
3609 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d",
3610 name
, active_objs
, num_objs
, cachep
->buffer_size
,
3611 cachep
->num
, (1 << cachep
->gfporder
));
3612 seq_printf(m
, " : tunables %4u %4u %4u",
3613 cachep
->limit
, cachep
->batchcount
, cachep
->shared
);
3614 seq_printf(m
, " : slabdata %6lu %6lu %6lu",
3615 active_slabs
, num_slabs
, shared_avail
);
3618 unsigned long high
= cachep
->high_mark
;
3619 unsigned long allocs
= cachep
->num_allocations
;
3620 unsigned long grown
= cachep
->grown
;
3621 unsigned long reaped
= cachep
->reaped
;
3622 unsigned long errors
= cachep
->errors
;
3623 unsigned long max_freeable
= cachep
->max_freeable
;
3624 unsigned long node_allocs
= cachep
->node_allocs
;
3625 unsigned long node_frees
= cachep
->node_frees
;
3627 seq_printf(m
, " : globalstat %7lu %6lu %5lu %4lu \
3628 %4lu %4lu %4lu %4lu", allocs
, high
, grown
, reaped
, errors
, max_freeable
, node_allocs
, node_frees
);
3632 unsigned long allochit
= atomic_read(&cachep
->allochit
);
3633 unsigned long allocmiss
= atomic_read(&cachep
->allocmiss
);
3634 unsigned long freehit
= atomic_read(&cachep
->freehit
);
3635 unsigned long freemiss
= atomic_read(&cachep
->freemiss
);
3637 seq_printf(m
, " : cpustat %6lu %6lu %6lu %6lu",
3638 allochit
, allocmiss
, freehit
, freemiss
);
3642 spin_unlock_irq(&cachep
->spinlock
);
3647 * slabinfo_op - iterator that generates /proc/slabinfo
3656 * num-pages-per-slab
3657 * + further values on SMP and with statistics enabled
3660 struct seq_operations slabinfo_op
= {
3667 #define MAX_SLABINFO_WRITE 128
3669 * slabinfo_write - Tuning for the slab allocator
3671 * @buffer: user buffer
3672 * @count: data length
3675 ssize_t
slabinfo_write(struct file
*file
, const char __user
* buffer
,
3676 size_t count
, loff_t
*ppos
)
3678 char kbuf
[MAX_SLABINFO_WRITE
+ 1], *tmp
;
3679 int limit
, batchcount
, shared
, res
;
3680 struct list_head
*p
;
3682 if (count
> MAX_SLABINFO_WRITE
)
3684 if (copy_from_user(&kbuf
, buffer
, count
))
3686 kbuf
[MAX_SLABINFO_WRITE
] = '\0';
3688 tmp
= strchr(kbuf
, ' ');
3693 if (sscanf(tmp
, " %d %d %d", &limit
, &batchcount
, &shared
) != 3)
3696 /* Find the cache in the chain of caches. */
3697 mutex_lock(&cache_chain_mutex
);
3699 list_for_each(p
, &cache_chain
) {
3700 struct kmem_cache
*cachep
= list_entry(p
, struct kmem_cache
,
3703 if (!strcmp(cachep
->name
, kbuf
)) {
3706 batchcount
> limit
|| shared
< 0) {
3709 res
= do_tune_cpucache(cachep
, limit
,
3710 batchcount
, shared
);
3715 mutex_unlock(&cache_chain_mutex
);
3723 * ksize - get the actual amount of memory allocated for a given object
3724 * @objp: Pointer to the object
3726 * kmalloc may internally round up allocations and return more memory
3727 * than requested. ksize() can be used to determine the actual amount of
3728 * memory allocated. The caller may use this additional memory, even though
3729 * a smaller amount of memory was initially specified with the kmalloc call.
3730 * The caller must guarantee that objp points to a valid object previously
3731 * allocated with either kmalloc() or kmem_cache_alloc(). The object
3732 * must not be freed during the duration of the call.
3734 unsigned int ksize(const void *objp
)
3736 if (unlikely(objp
== NULL
))
3739 return obj_size(virt_to_cache(objp
));