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 unsigned int colour_next
; /* Per-node cache coloring */
298 spinlock_t list_lock
;
299 struct array_cache
*shared
; /* shared per node */
300 struct array_cache
**alien
; /* on other nodes */
304 * Need this for bootstrapping a per node allocator.
306 #define NUM_INIT_LISTS (2 * MAX_NUMNODES + 1)
307 struct kmem_list3 __initdata initkmem_list3
[NUM_INIT_LISTS
];
308 #define CACHE_CACHE 0
310 #define SIZE_L3 (1 + MAX_NUMNODES)
313 * This function must be completely optimized away if
314 * a constant is passed to it. Mostly the same as
315 * what is in linux/slab.h except it returns an
318 static __always_inline
int index_of(const size_t size
)
320 extern void __bad_size(void);
322 if (__builtin_constant_p(size
)) {
330 #include "linux/kmalloc_sizes.h"
338 #define INDEX_AC index_of(sizeof(struct arraycache_init))
339 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
341 static void kmem_list3_init(struct kmem_list3
*parent
)
343 INIT_LIST_HEAD(&parent
->slabs_full
);
344 INIT_LIST_HEAD(&parent
->slabs_partial
);
345 INIT_LIST_HEAD(&parent
->slabs_free
);
346 parent
->shared
= NULL
;
347 parent
->alien
= NULL
;
348 parent
->colour_next
= 0;
349 spin_lock_init(&parent
->list_lock
);
350 parent
->free_objects
= 0;
351 parent
->free_touched
= 0;
354 #define MAKE_LIST(cachep, listp, slab, nodeid) \
356 INIT_LIST_HEAD(listp); \
357 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
360 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
362 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
363 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
364 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
374 /* 1) per-cpu data, touched during every alloc/free */
375 struct array_cache
*array
[NR_CPUS
];
376 unsigned int batchcount
;
379 unsigned int buffer_size
;
380 /* 2) touched by every alloc & free from the backend */
381 struct kmem_list3
*nodelists
[MAX_NUMNODES
];
382 unsigned int flags
; /* constant flags */
383 unsigned int num
; /* # of objs per slab */
386 /* 3) cache_grow/shrink */
387 /* order of pgs per slab (2^n) */
388 unsigned int gfporder
;
390 /* force GFP flags, e.g. GFP_DMA */
393 size_t colour
; /* cache colouring range */
394 unsigned int colour_off
; /* colour offset */
395 struct kmem_cache
*slabp_cache
;
396 unsigned int slab_size
;
397 unsigned int dflags
; /* dynamic flags */
399 /* constructor func */
400 void (*ctor
) (void *, struct kmem_cache
*, unsigned long);
402 /* de-constructor func */
403 void (*dtor
) (void *, struct kmem_cache
*, unsigned long);
405 /* 4) cache creation/removal */
407 struct list_head next
;
411 unsigned long num_active
;
412 unsigned long num_allocations
;
413 unsigned long high_mark
;
415 unsigned long reaped
;
416 unsigned long errors
;
417 unsigned long max_freeable
;
418 unsigned long node_allocs
;
419 unsigned long node_frees
;
427 * If debugging is enabled, then the allocator can add additional
428 * fields and/or padding to every object. buffer_size contains the total
429 * object size including these internal fields, the following two
430 * variables contain the offset to the user object and its size.
437 #define CFLGS_OFF_SLAB (0x80000000UL)
438 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
440 #define BATCHREFILL_LIMIT 16
441 /* Optimization question: fewer reaps means less
442 * probability for unnessary cpucache drain/refill cycles.
444 * OTOH the cpuarrays can contain lots of objects,
445 * which could lock up otherwise freeable slabs.
447 #define REAPTIMEOUT_CPUC (2*HZ)
448 #define REAPTIMEOUT_LIST3 (4*HZ)
451 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
452 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
453 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
454 #define STATS_INC_GROWN(x) ((x)->grown++)
455 #define STATS_INC_REAPED(x) ((x)->reaped++)
456 #define STATS_SET_HIGH(x) do { if ((x)->num_active > (x)->high_mark) \
457 (x)->high_mark = (x)->num_active; \
459 #define STATS_INC_ERR(x) ((x)->errors++)
460 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
461 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
462 #define STATS_SET_FREEABLE(x, i) \
463 do { if ((x)->max_freeable < i) \
464 (x)->max_freeable = i; \
467 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
468 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
469 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
470 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
472 #define STATS_INC_ACTIVE(x) do { } while (0)
473 #define STATS_DEC_ACTIVE(x) do { } while (0)
474 #define STATS_INC_ALLOCED(x) do { } while (0)
475 #define STATS_INC_GROWN(x) do { } while (0)
476 #define STATS_INC_REAPED(x) do { } while (0)
477 #define STATS_SET_HIGH(x) do { } while (0)
478 #define STATS_INC_ERR(x) do { } while (0)
479 #define STATS_INC_NODEALLOCS(x) do { } while (0)
480 #define STATS_INC_NODEFREES(x) do { } while (0)
481 #define STATS_SET_FREEABLE(x, i) \
484 #define STATS_INC_ALLOCHIT(x) do { } while (0)
485 #define STATS_INC_ALLOCMISS(x) do { } while (0)
486 #define STATS_INC_FREEHIT(x) do { } while (0)
487 #define STATS_INC_FREEMISS(x) do { } while (0)
491 /* Magic nums for obj red zoning.
492 * Placed in the first word before and the first word after an obj.
494 #define RED_INACTIVE 0x5A2CF071UL /* when obj is inactive */
495 #define RED_ACTIVE 0x170FC2A5UL /* when obj is active */
497 /* ...and for poisoning */
498 #define POISON_INUSE 0x5a /* for use-uninitialised poisoning */
499 #define POISON_FREE 0x6b /* for use-after-free poisoning */
500 #define POISON_END 0xa5 /* end-byte of poisoning */
502 /* memory layout of objects:
504 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
505 * the end of an object is aligned with the end of the real
506 * allocation. Catches writes behind the end of the allocation.
507 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
509 * cachep->obj_offset: The real object.
510 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
511 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address [BYTES_PER_WORD long]
513 static int obj_offset(struct kmem_cache
*cachep
)
515 return cachep
->obj_offset
;
518 static int obj_size(struct kmem_cache
*cachep
)
520 return cachep
->obj_size
;
523 static unsigned long *dbg_redzone1(struct kmem_cache
*cachep
, void *objp
)
525 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
526 return (unsigned long*) (objp
+obj_offset(cachep
)-BYTES_PER_WORD
);
529 static unsigned long *dbg_redzone2(struct kmem_cache
*cachep
, void *objp
)
531 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
532 if (cachep
->flags
& SLAB_STORE_USER
)
533 return (unsigned long *)(objp
+ cachep
->buffer_size
-
535 return (unsigned long *)(objp
+ cachep
->buffer_size
- BYTES_PER_WORD
);
538 static void **dbg_userword(struct kmem_cache
*cachep
, void *objp
)
540 BUG_ON(!(cachep
->flags
& SLAB_STORE_USER
));
541 return (void **)(objp
+ cachep
->buffer_size
- BYTES_PER_WORD
);
546 #define obj_offset(x) 0
547 #define obj_size(cachep) (cachep->buffer_size)
548 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long *)NULL;})
549 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long *)NULL;})
550 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
555 * Maximum size of an obj (in 2^order pages)
556 * and absolute limit for the gfp order.
558 #if defined(CONFIG_LARGE_ALLOCS)
559 #define MAX_OBJ_ORDER 13 /* up to 32Mb */
560 #define MAX_GFP_ORDER 13 /* up to 32Mb */
561 #elif defined(CONFIG_MMU)
562 #define MAX_OBJ_ORDER 5 /* 32 pages */
563 #define MAX_GFP_ORDER 5 /* 32 pages */
565 #define MAX_OBJ_ORDER 8 /* up to 1Mb */
566 #define MAX_GFP_ORDER 8 /* up to 1Mb */
570 * Do not go above this order unless 0 objects fit into the slab.
572 #define BREAK_GFP_ORDER_HI 1
573 #define BREAK_GFP_ORDER_LO 0
574 static int slab_break_gfp_order
= BREAK_GFP_ORDER_LO
;
576 /* Functions for storing/retrieving the cachep and or slab from the
577 * global 'mem_map'. These are used to find the slab an obj belongs to.
578 * With kfree(), these are used to find the cache which an obj belongs to.
580 static inline void page_set_cache(struct page
*page
, struct kmem_cache
*cache
)
582 page
->lru
.next
= (struct list_head
*)cache
;
585 static inline struct kmem_cache
*page_get_cache(struct page
*page
)
587 return (struct kmem_cache
*)page
->lru
.next
;
590 static inline void page_set_slab(struct page
*page
, struct slab
*slab
)
592 page
->lru
.prev
= (struct list_head
*)slab
;
595 static inline struct slab
*page_get_slab(struct page
*page
)
597 return (struct slab
*)page
->lru
.prev
;
600 static inline struct kmem_cache
*virt_to_cache(const void *obj
)
602 struct page
*page
= virt_to_page(obj
);
603 return page_get_cache(page
);
606 static inline struct slab
*virt_to_slab(const void *obj
)
608 struct page
*page
= virt_to_page(obj
);
609 return page_get_slab(page
);
612 /* These are the default caches for kmalloc. Custom caches can have other sizes. */
613 struct cache_sizes malloc_sizes
[] = {
614 #define CACHE(x) { .cs_size = (x) },
615 #include <linux/kmalloc_sizes.h>
619 EXPORT_SYMBOL(malloc_sizes
);
621 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
627 static struct cache_names __initdata cache_names
[] = {
628 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
629 #include <linux/kmalloc_sizes.h>
634 static struct arraycache_init initarray_cache __initdata
=
635 { {0, BOOT_CPUCACHE_ENTRIES
, 1, 0} };
636 static struct arraycache_init initarray_generic
=
637 { {0, BOOT_CPUCACHE_ENTRIES
, 1, 0} };
639 /* internal cache of cache description objs */
640 static struct kmem_cache cache_cache
= {
642 .limit
= BOOT_CPUCACHE_ENTRIES
,
644 .buffer_size
= sizeof(struct kmem_cache
),
645 .flags
= SLAB_NO_REAP
,
646 .spinlock
= SPIN_LOCK_UNLOCKED
,
647 .name
= "kmem_cache",
649 .obj_size
= sizeof(struct kmem_cache
),
653 /* Guard access to the cache-chain. */
654 static DEFINE_MUTEX(cache_chain_mutex
);
655 static struct list_head cache_chain
;
658 * vm_enough_memory() looks at this to determine how many
659 * slab-allocated pages are possibly freeable under pressure
661 * SLAB_RECLAIM_ACCOUNT turns this on per-slab
663 atomic_t slab_reclaim_pages
;
666 * chicken and egg problem: delay the per-cpu array allocation
667 * until the general caches are up.
676 static DEFINE_PER_CPU(struct work_struct
, reap_work
);
678 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int len
, int node
);
679 static void enable_cpucache(struct kmem_cache
*cachep
);
680 static void cache_reap(void *unused
);
681 static int __node_shrink(struct kmem_cache
*cachep
, int node
);
683 static inline struct array_cache
*cpu_cache_get(struct kmem_cache
*cachep
)
685 return cachep
->array
[smp_processor_id()];
688 static inline struct kmem_cache
*__find_general_cachep(size_t size
, gfp_t gfpflags
)
690 struct cache_sizes
*csizep
= malloc_sizes
;
693 /* This happens if someone tries to call
694 * kmem_cache_create(), or __kmalloc(), before
695 * the generic caches are initialized.
697 BUG_ON(malloc_sizes
[INDEX_AC
].cs_cachep
== NULL
);
699 while (size
> csizep
->cs_size
)
703 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
704 * has cs_{dma,}cachep==NULL. Thus no special case
705 * for large kmalloc calls required.
707 if (unlikely(gfpflags
& GFP_DMA
))
708 return csizep
->cs_dmacachep
;
709 return csizep
->cs_cachep
;
712 struct kmem_cache
*kmem_find_general_cachep(size_t size
, gfp_t gfpflags
)
714 return __find_general_cachep(size
, gfpflags
);
716 EXPORT_SYMBOL(kmem_find_general_cachep
);
718 static size_t slab_mgmt_size(size_t nr_objs
, size_t align
)
720 return ALIGN(sizeof(struct slab
)+nr_objs
*sizeof(kmem_bufctl_t
), align
);
723 /* Calculate the number of objects and left-over bytes for a given
725 static void cache_estimate(unsigned long gfporder
, size_t buffer_size
,
726 size_t align
, int flags
, size_t *left_over
,
731 size_t slab_size
= PAGE_SIZE
<< gfporder
;
734 * The slab management structure can be either off the slab or
735 * on it. For the latter case, the memory allocated for a
739 * - One kmem_bufctl_t for each object
740 * - Padding to respect alignment of @align
741 * - @buffer_size bytes for each object
743 * If the slab management structure is off the slab, then the
744 * alignment will already be calculated into the size. Because
745 * the slabs are all pages aligned, the objects will be at the
746 * correct alignment when allocated.
748 if (flags
& CFLGS_OFF_SLAB
) {
750 nr_objs
= slab_size
/ buffer_size
;
752 if (nr_objs
> SLAB_LIMIT
)
753 nr_objs
= SLAB_LIMIT
;
756 * Ignore padding for the initial guess. The padding
757 * is at most @align-1 bytes, and @buffer_size is at
758 * least @align. In the worst case, this result will
759 * be one greater than the number of objects that fit
760 * into the memory allocation when taking the padding
763 nr_objs
= (slab_size
- sizeof(struct slab
)) /
764 (buffer_size
+ sizeof(kmem_bufctl_t
));
767 * This calculated number will be either the right
768 * amount, or one greater than what we want.
770 if (slab_mgmt_size(nr_objs
, align
) + nr_objs
*buffer_size
774 if (nr_objs
> SLAB_LIMIT
)
775 nr_objs
= SLAB_LIMIT
;
777 mgmt_size
= slab_mgmt_size(nr_objs
, align
);
780 *left_over
= slab_size
- nr_objs
*buffer_size
- mgmt_size
;
783 #define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg)
785 static void __slab_error(const char *function
, struct kmem_cache
*cachep
, char *msg
)
787 printk(KERN_ERR
"slab error in %s(): cache `%s': %s\n",
788 function
, cachep
->name
, msg
);
793 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
794 * via the workqueue/eventd.
795 * Add the CPU number into the expiration time to minimize the possibility of
796 * the CPUs getting into lockstep and contending for the global cache chain
799 static void __devinit
start_cpu_timer(int cpu
)
801 struct work_struct
*reap_work
= &per_cpu(reap_work
, cpu
);
804 * When this gets called from do_initcalls via cpucache_init(),
805 * init_workqueues() has already run, so keventd will be setup
808 if (keventd_up() && reap_work
->func
== NULL
) {
809 INIT_WORK(reap_work
, cache_reap
, NULL
);
810 schedule_delayed_work_on(cpu
, reap_work
, HZ
+ 3 * cpu
);
814 static struct array_cache
*alloc_arraycache(int node
, int entries
,
817 int memsize
= sizeof(void *) * entries
+ sizeof(struct array_cache
);
818 struct array_cache
*nc
= NULL
;
820 nc
= kmalloc_node(memsize
, GFP_KERNEL
, node
);
824 nc
->batchcount
= batchcount
;
826 spin_lock_init(&nc
->lock
);
832 static void *__cache_alloc_node(struct kmem_cache
*, gfp_t
, int);
834 static struct array_cache
**alloc_alien_cache(int node
, int limit
)
836 struct array_cache
**ac_ptr
;
837 int memsize
= sizeof(void *) * MAX_NUMNODES
;
842 ac_ptr
= kmalloc_node(memsize
, GFP_KERNEL
, node
);
845 if (i
== node
|| !node_online(i
)) {
849 ac_ptr
[i
] = alloc_arraycache(node
, limit
, 0xbaadf00d);
851 for (i
--; i
<= 0; i
--)
861 static void free_alien_cache(struct array_cache
**ac_ptr
)
874 static void __drain_alien_cache(struct kmem_cache
*cachep
,
875 struct array_cache
*ac
, int node
)
877 struct kmem_list3
*rl3
= cachep
->nodelists
[node
];
880 spin_lock(&rl3
->list_lock
);
881 free_block(cachep
, ac
->entry
, ac
->avail
, node
);
883 spin_unlock(&rl3
->list_lock
);
887 static void drain_alien_cache(struct kmem_cache
*cachep
, struct array_cache
**alien
)
890 struct array_cache
*ac
;
893 for_each_online_node(i
) {
896 spin_lock_irqsave(&ac
->lock
, flags
);
897 __drain_alien_cache(cachep
, ac
, i
);
898 spin_unlock_irqrestore(&ac
->lock
, flags
);
903 #define alloc_alien_cache(node, limit) do { } while (0)
904 #define drain_alien_cache(cachep, alien) do { } while (0)
906 static inline void free_alien_cache(struct array_cache
**ac_ptr
)
911 static int __devinit
cpuup_callback(struct notifier_block
*nfb
,
912 unsigned long action
, void *hcpu
)
914 long cpu
= (long)hcpu
;
915 struct kmem_cache
*cachep
;
916 struct kmem_list3
*l3
= NULL
;
917 int node
= cpu_to_node(cpu
);
918 int memsize
= sizeof(struct kmem_list3
);
922 mutex_lock(&cache_chain_mutex
);
923 /* we need to do this right in the beginning since
924 * alloc_arraycache's are going to use this list.
925 * kmalloc_node allows us to add the slab to the right
926 * kmem_list3 and not this cpu's kmem_list3
929 list_for_each_entry(cachep
, &cache_chain
, next
) {
930 /* setup the size64 kmemlist for cpu before we can
931 * begin anything. Make sure some other cpu on this
932 * node has not already allocated this
934 if (!cachep
->nodelists
[node
]) {
935 if (!(l3
= kmalloc_node(memsize
,
939 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
+
940 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
943 * The l3s don't come and go as CPUs come and
944 * go. cache_chain_mutex is sufficient
947 cachep
->nodelists
[node
] = l3
;
950 spin_lock_irq(&cachep
->nodelists
[node
]->list_lock
);
951 cachep
->nodelists
[node
]->free_limit
=
952 (1 + nr_cpus_node(node
)) *
953 cachep
->batchcount
+ cachep
->num
;
954 spin_unlock_irq(&cachep
->nodelists
[node
]->list_lock
);
957 /* Now we can go ahead with allocating the shared array's
959 list_for_each_entry(cachep
, &cache_chain
, next
) {
960 struct array_cache
*nc
;
961 struct array_cache
*shared
;
962 struct array_cache
**alien
;
964 nc
= alloc_arraycache(node
, cachep
->limit
,
968 shared
= alloc_arraycache(node
,
969 cachep
->shared
* cachep
->batchcount
,
974 alien
= alloc_alien_cache(node
, cachep
->limit
);
978 cachep
->array
[cpu
] = nc
;
980 l3
= cachep
->nodelists
[node
];
983 spin_lock_irq(&l3
->list_lock
);
986 * We are serialised from CPU_DEAD or
987 * CPU_UP_CANCELLED by the cpucontrol lock
998 spin_unlock_irq(&l3
->list_lock
);
1001 free_alien_cache(alien
);
1003 mutex_unlock(&cache_chain_mutex
);
1006 start_cpu_timer(cpu
);
1008 #ifdef CONFIG_HOTPLUG_CPU
1011 * Even if all the cpus of a node are down, we don't free the
1012 * kmem_list3 of any cache. This to avoid a race between
1013 * cpu_down, and a kmalloc allocation from another cpu for
1014 * memory from the node of the cpu going down. The list3
1015 * structure is usually allocated from kmem_cache_create() and
1016 * gets destroyed at kmem_cache_destroy().
1019 case CPU_UP_CANCELED
:
1020 mutex_lock(&cache_chain_mutex
);
1022 list_for_each_entry(cachep
, &cache_chain
, next
) {
1023 struct array_cache
*nc
;
1024 struct array_cache
*shared
;
1025 struct array_cache
**alien
;
1028 mask
= node_to_cpumask(node
);
1029 /* cpu is dead; no one can alloc from it. */
1030 nc
= cachep
->array
[cpu
];
1031 cachep
->array
[cpu
] = NULL
;
1032 l3
= cachep
->nodelists
[node
];
1035 goto free_array_cache
;
1037 spin_lock_irq(&l3
->list_lock
);
1039 /* Free limit for this kmem_list3 */
1040 l3
->free_limit
-= cachep
->batchcount
;
1042 free_block(cachep
, nc
->entry
, nc
->avail
, node
);
1044 if (!cpus_empty(mask
)) {
1045 spin_unlock_irq(&l3
->list_lock
);
1046 goto free_array_cache
;
1049 shared
= l3
->shared
;
1051 free_block(cachep
, l3
->shared
->entry
,
1052 l3
->shared
->avail
, node
);
1059 spin_unlock_irq(&l3
->list_lock
);
1063 drain_alien_cache(cachep
, alien
);
1064 free_alien_cache(alien
);
1070 * In the previous loop, all the objects were freed to
1071 * the respective cache's slabs, now we can go ahead and
1072 * shrink each nodelist to its limit.
1074 list_for_each_entry(cachep
, &cache_chain
, next
) {
1075 l3
= cachep
->nodelists
[node
];
1078 spin_lock_irq(&l3
->list_lock
);
1079 /* free slabs belonging to this node */
1080 __node_shrink(cachep
, node
);
1081 spin_unlock_irq(&l3
->list_lock
);
1083 mutex_unlock(&cache_chain_mutex
);
1089 mutex_unlock(&cache_chain_mutex
);
1093 static struct notifier_block cpucache_notifier
= { &cpuup_callback
, NULL
, 0 };
1096 * swap the static kmem_list3 with kmalloced memory
1098 static void init_list(struct kmem_cache
*cachep
, struct kmem_list3
*list
, int nodeid
)
1100 struct kmem_list3
*ptr
;
1102 BUG_ON(cachep
->nodelists
[nodeid
] != list
);
1103 ptr
= kmalloc_node(sizeof(struct kmem_list3
), GFP_KERNEL
, nodeid
);
1106 local_irq_disable();
1107 memcpy(ptr
, list
, sizeof(struct kmem_list3
));
1108 MAKE_ALL_LISTS(cachep
, ptr
, nodeid
);
1109 cachep
->nodelists
[nodeid
] = ptr
;
1114 * Called after the gfp() functions have been enabled, and before smp_init().
1116 void __init
kmem_cache_init(void)
1119 struct cache_sizes
*sizes
;
1120 struct cache_names
*names
;
1123 for (i
= 0; i
< NUM_INIT_LISTS
; i
++) {
1124 kmem_list3_init(&initkmem_list3
[i
]);
1125 if (i
< MAX_NUMNODES
)
1126 cache_cache
.nodelists
[i
] = NULL
;
1130 * Fragmentation resistance on low memory - only use bigger
1131 * page orders on machines with more than 32MB of memory.
1133 if (num_physpages
> (32 << 20) >> PAGE_SHIFT
)
1134 slab_break_gfp_order
= BREAK_GFP_ORDER_HI
;
1136 /* Bootstrap is tricky, because several objects are allocated
1137 * from caches that do not exist yet:
1138 * 1) initialize the cache_cache cache: it contains the struct kmem_cache
1139 * structures of all caches, except cache_cache itself: cache_cache
1140 * is statically allocated.
1141 * Initially an __init data area is used for the head array and the
1142 * kmem_list3 structures, it's replaced with a kmalloc allocated
1143 * array at the end of the bootstrap.
1144 * 2) Create the first kmalloc cache.
1145 * The struct kmem_cache for the new cache is allocated normally.
1146 * An __init data area is used for the head array.
1147 * 3) Create the remaining kmalloc caches, with minimally sized
1149 * 4) Replace the __init data head arrays for cache_cache and the first
1150 * kmalloc cache with kmalloc allocated arrays.
1151 * 5) Replace the __init data for kmem_list3 for cache_cache and
1152 * the other cache's with kmalloc allocated memory.
1153 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1156 /* 1) create the cache_cache */
1157 INIT_LIST_HEAD(&cache_chain
);
1158 list_add(&cache_cache
.next
, &cache_chain
);
1159 cache_cache
.colour_off
= cache_line_size();
1160 cache_cache
.array
[smp_processor_id()] = &initarray_cache
.cache
;
1161 cache_cache
.nodelists
[numa_node_id()] = &initkmem_list3
[CACHE_CACHE
];
1163 cache_cache
.buffer_size
= ALIGN(cache_cache
.buffer_size
, cache_line_size());
1165 cache_estimate(0, cache_cache
.buffer_size
, cache_line_size(), 0,
1166 &left_over
, &cache_cache
.num
);
1167 if (!cache_cache
.num
)
1170 cache_cache
.colour
= left_over
/ cache_cache
.colour_off
;
1171 cache_cache
.slab_size
= ALIGN(cache_cache
.num
* sizeof(kmem_bufctl_t
) +
1172 sizeof(struct slab
), cache_line_size());
1174 /* 2+3) create the kmalloc caches */
1175 sizes
= malloc_sizes
;
1176 names
= cache_names
;
1178 /* Initialize the caches that provide memory for the array cache
1179 * and the kmem_list3 structures first.
1180 * Without this, further allocations will bug
1183 sizes
[INDEX_AC
].cs_cachep
= kmem_cache_create(names
[INDEX_AC
].name
,
1184 sizes
[INDEX_AC
].cs_size
,
1185 ARCH_KMALLOC_MINALIGN
,
1186 (ARCH_KMALLOC_FLAGS
|
1187 SLAB_PANIC
), NULL
, NULL
);
1189 if (INDEX_AC
!= INDEX_L3
)
1190 sizes
[INDEX_L3
].cs_cachep
=
1191 kmem_cache_create(names
[INDEX_L3
].name
,
1192 sizes
[INDEX_L3
].cs_size
,
1193 ARCH_KMALLOC_MINALIGN
,
1194 (ARCH_KMALLOC_FLAGS
| SLAB_PANIC
), NULL
,
1197 while (sizes
->cs_size
!= ULONG_MAX
) {
1199 * For performance, all the general caches are L1 aligned.
1200 * This should be particularly beneficial on SMP boxes, as it
1201 * eliminates "false sharing".
1202 * Note for systems short on memory removing the alignment will
1203 * allow tighter packing of the smaller caches.
1205 if (!sizes
->cs_cachep
)
1206 sizes
->cs_cachep
= kmem_cache_create(names
->name
,
1208 ARCH_KMALLOC_MINALIGN
,
1213 /* Inc off-slab bufctl limit until the ceiling is hit. */
1214 if (!(OFF_SLAB(sizes
->cs_cachep
))) {
1215 offslab_limit
= sizes
->cs_size
- sizeof(struct slab
);
1216 offslab_limit
/= sizeof(kmem_bufctl_t
);
1219 sizes
->cs_dmacachep
= kmem_cache_create(names
->name_dma
,
1221 ARCH_KMALLOC_MINALIGN
,
1222 (ARCH_KMALLOC_FLAGS
|
1230 /* 4) Replace the bootstrap head arrays */
1234 ptr
= kmalloc(sizeof(struct arraycache_init
), GFP_KERNEL
);
1236 local_irq_disable();
1237 BUG_ON(cpu_cache_get(&cache_cache
) != &initarray_cache
.cache
);
1238 memcpy(ptr
, cpu_cache_get(&cache_cache
),
1239 sizeof(struct arraycache_init
));
1240 cache_cache
.array
[smp_processor_id()] = ptr
;
1243 ptr
= kmalloc(sizeof(struct arraycache_init
), GFP_KERNEL
);
1245 local_irq_disable();
1246 BUG_ON(cpu_cache_get(malloc_sizes
[INDEX_AC
].cs_cachep
)
1247 != &initarray_generic
.cache
);
1248 memcpy(ptr
, cpu_cache_get(malloc_sizes
[INDEX_AC
].cs_cachep
),
1249 sizeof(struct arraycache_init
));
1250 malloc_sizes
[INDEX_AC
].cs_cachep
->array
[smp_processor_id()] =
1254 /* 5) Replace the bootstrap kmem_list3's */
1257 /* Replace the static kmem_list3 structures for the boot cpu */
1258 init_list(&cache_cache
, &initkmem_list3
[CACHE_CACHE
],
1261 for_each_online_node(node
) {
1262 init_list(malloc_sizes
[INDEX_AC
].cs_cachep
,
1263 &initkmem_list3
[SIZE_AC
+ node
], node
);
1265 if (INDEX_AC
!= INDEX_L3
) {
1266 init_list(malloc_sizes
[INDEX_L3
].cs_cachep
,
1267 &initkmem_list3
[SIZE_L3
+ node
],
1273 /* 6) resize the head arrays to their final sizes */
1275 struct kmem_cache
*cachep
;
1276 mutex_lock(&cache_chain_mutex
);
1277 list_for_each_entry(cachep
, &cache_chain
, next
)
1278 enable_cpucache(cachep
);
1279 mutex_unlock(&cache_chain_mutex
);
1283 g_cpucache_up
= FULL
;
1285 /* Register a cpu startup notifier callback
1286 * that initializes cpu_cache_get for all new cpus
1288 register_cpu_notifier(&cpucache_notifier
);
1290 /* The reap timers are started later, with a module init call:
1291 * That part of the kernel is not yet operational.
1295 static int __init
cpucache_init(void)
1300 * Register the timers that return unneeded
1303 for_each_online_cpu(cpu
)
1304 start_cpu_timer(cpu
);
1309 __initcall(cpucache_init
);
1312 * Interface to system's page allocator. No need to hold the cache-lock.
1314 * If we requested dmaable memory, we will get it. Even if we
1315 * did not request dmaable memory, we might get it, but that
1316 * would be relatively rare and ignorable.
1318 static void *kmem_getpages(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
1324 flags
|= cachep
->gfpflags
;
1325 page
= alloc_pages_node(nodeid
, flags
, cachep
->gfporder
);
1328 addr
= page_address(page
);
1330 i
= (1 << cachep
->gfporder
);
1331 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1332 atomic_add(i
, &slab_reclaim_pages
);
1333 add_page_state(nr_slab
, i
);
1342 * Interface to system's page release.
1344 static void kmem_freepages(struct kmem_cache
*cachep
, void *addr
)
1346 unsigned long i
= (1 << cachep
->gfporder
);
1347 struct page
*page
= virt_to_page(addr
);
1348 const unsigned long nr_freed
= i
;
1351 if (!TestClearPageSlab(page
))
1355 sub_page_state(nr_slab
, nr_freed
);
1356 if (current
->reclaim_state
)
1357 current
->reclaim_state
->reclaimed_slab
+= nr_freed
;
1358 free_pages((unsigned long)addr
, cachep
->gfporder
);
1359 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1360 atomic_sub(1 << cachep
->gfporder
, &slab_reclaim_pages
);
1363 static void kmem_rcu_free(struct rcu_head
*head
)
1365 struct slab_rcu
*slab_rcu
= (struct slab_rcu
*)head
;
1366 struct kmem_cache
*cachep
= slab_rcu
->cachep
;
1368 kmem_freepages(cachep
, slab_rcu
->addr
);
1369 if (OFF_SLAB(cachep
))
1370 kmem_cache_free(cachep
->slabp_cache
, slab_rcu
);
1375 #ifdef CONFIG_DEBUG_PAGEALLOC
1376 static void store_stackinfo(struct kmem_cache
*cachep
, unsigned long *addr
,
1377 unsigned long caller
)
1379 int size
= obj_size(cachep
);
1381 addr
= (unsigned long *)&((char *)addr
)[obj_offset(cachep
)];
1383 if (size
< 5 * sizeof(unsigned long))
1386 *addr
++ = 0x12345678;
1388 *addr
++ = smp_processor_id();
1389 size
-= 3 * sizeof(unsigned long);
1391 unsigned long *sptr
= &caller
;
1392 unsigned long svalue
;
1394 while (!kstack_end(sptr
)) {
1396 if (kernel_text_address(svalue
)) {
1398 size
-= sizeof(unsigned long);
1399 if (size
<= sizeof(unsigned long))
1405 *addr
++ = 0x87654321;
1409 static void poison_obj(struct kmem_cache
*cachep
, void *addr
, unsigned char val
)
1411 int size
= obj_size(cachep
);
1412 addr
= &((char *)addr
)[obj_offset(cachep
)];
1414 memset(addr
, val
, size
);
1415 *(unsigned char *)(addr
+ size
- 1) = POISON_END
;
1418 static void dump_line(char *data
, int offset
, int limit
)
1421 printk(KERN_ERR
"%03x:", offset
);
1422 for (i
= 0; i
< limit
; i
++) {
1423 printk(" %02x", (unsigned char)data
[offset
+ i
]);
1431 static void print_objinfo(struct kmem_cache
*cachep
, void *objp
, int lines
)
1436 if (cachep
->flags
& SLAB_RED_ZONE
) {
1437 printk(KERN_ERR
"Redzone: 0x%lx/0x%lx.\n",
1438 *dbg_redzone1(cachep
, objp
),
1439 *dbg_redzone2(cachep
, objp
));
1442 if (cachep
->flags
& SLAB_STORE_USER
) {
1443 printk(KERN_ERR
"Last user: [<%p>]",
1444 *dbg_userword(cachep
, objp
));
1445 print_symbol("(%s)",
1446 (unsigned long)*dbg_userword(cachep
, objp
));
1449 realobj
= (char *)objp
+ obj_offset(cachep
);
1450 size
= obj_size(cachep
);
1451 for (i
= 0; i
< size
&& lines
; i
+= 16, lines
--) {
1454 if (i
+ limit
> size
)
1456 dump_line(realobj
, i
, limit
);
1460 static void check_poison_obj(struct kmem_cache
*cachep
, void *objp
)
1466 realobj
= (char *)objp
+ obj_offset(cachep
);
1467 size
= obj_size(cachep
);
1469 for (i
= 0; i
< size
; i
++) {
1470 char exp
= POISON_FREE
;
1473 if (realobj
[i
] != exp
) {
1479 "Slab corruption: start=%p, len=%d\n",
1481 print_objinfo(cachep
, objp
, 0);
1483 /* Hexdump the affected line */
1486 if (i
+ limit
> size
)
1488 dump_line(realobj
, i
, limit
);
1491 /* Limit to 5 lines */
1497 /* Print some data about the neighboring objects, if they
1500 struct slab
*slabp
= virt_to_slab(objp
);
1503 objnr
= (unsigned)(objp
- slabp
->s_mem
) / cachep
->buffer_size
;
1505 objp
= slabp
->s_mem
+ (objnr
- 1) * cachep
->buffer_size
;
1506 realobj
= (char *)objp
+ obj_offset(cachep
);
1507 printk(KERN_ERR
"Prev obj: start=%p, len=%d\n",
1509 print_objinfo(cachep
, objp
, 2);
1511 if (objnr
+ 1 < cachep
->num
) {
1512 objp
= slabp
->s_mem
+ (objnr
+ 1) * cachep
->buffer_size
;
1513 realobj
= (char *)objp
+ obj_offset(cachep
);
1514 printk(KERN_ERR
"Next obj: start=%p, len=%d\n",
1516 print_objinfo(cachep
, objp
, 2);
1524 * slab_destroy_objs - call the registered destructor for each object in
1525 * a slab that is to be destroyed.
1527 static void slab_destroy_objs(struct kmem_cache
*cachep
, struct slab
*slabp
)
1530 for (i
= 0; i
< cachep
->num
; i
++) {
1531 void *objp
= slabp
->s_mem
+ cachep
->buffer_size
* i
;
1533 if (cachep
->flags
& SLAB_POISON
) {
1534 #ifdef CONFIG_DEBUG_PAGEALLOC
1535 if ((cachep
->buffer_size
% PAGE_SIZE
) == 0
1536 && OFF_SLAB(cachep
))
1537 kernel_map_pages(virt_to_page(objp
),
1538 cachep
->buffer_size
/ PAGE_SIZE
,
1541 check_poison_obj(cachep
, objp
);
1543 check_poison_obj(cachep
, objp
);
1546 if (cachep
->flags
& SLAB_RED_ZONE
) {
1547 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
1548 slab_error(cachep
, "start of a freed object "
1550 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
1551 slab_error(cachep
, "end of a freed object "
1554 if (cachep
->dtor
&& !(cachep
->flags
& SLAB_POISON
))
1555 (cachep
->dtor
) (objp
+ obj_offset(cachep
), cachep
, 0);
1559 static void slab_destroy_objs(struct kmem_cache
*cachep
, struct slab
*slabp
)
1563 for (i
= 0; i
< cachep
->num
; i
++) {
1564 void *objp
= slabp
->s_mem
+ cachep
->buffer_size
* i
;
1565 (cachep
->dtor
) (objp
, cachep
, 0);
1572 * Destroy all the objs in a slab, and release the mem back to the system.
1573 * Before calling the slab must have been unlinked from the cache.
1574 * The cache-lock is not held/needed.
1576 static void slab_destroy(struct kmem_cache
*cachep
, struct slab
*slabp
)
1578 void *addr
= slabp
->s_mem
- slabp
->colouroff
;
1580 slab_destroy_objs(cachep
, slabp
);
1581 if (unlikely(cachep
->flags
& SLAB_DESTROY_BY_RCU
)) {
1582 struct slab_rcu
*slab_rcu
;
1584 slab_rcu
= (struct slab_rcu
*)slabp
;
1585 slab_rcu
->cachep
= cachep
;
1586 slab_rcu
->addr
= addr
;
1587 call_rcu(&slab_rcu
->head
, kmem_rcu_free
);
1589 kmem_freepages(cachep
, addr
);
1590 if (OFF_SLAB(cachep
))
1591 kmem_cache_free(cachep
->slabp_cache
, slabp
);
1595 /* For setting up all the kmem_list3s for cache whose buffer_size is same
1596 as size of kmem_list3. */
1597 static void set_up_list3s(struct kmem_cache
*cachep
, int index
)
1601 for_each_online_node(node
) {
1602 cachep
->nodelists
[node
] = &initkmem_list3
[index
+ node
];
1603 cachep
->nodelists
[node
]->next_reap
= jiffies
+
1605 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
1610 * calculate_slab_order - calculate size (page order) of slabs
1611 * @cachep: pointer to the cache that is being created
1612 * @size: size of objects to be created in this cache.
1613 * @align: required alignment for the objects.
1614 * @flags: slab allocation flags
1616 * Also calculates the number of objects per slab.
1618 * This could be made much more intelligent. For now, try to avoid using
1619 * high order pages for slabs. When the gfp() functions are more friendly
1620 * towards high-order requests, this should be changed.
1622 static inline size_t calculate_slab_order(struct kmem_cache
*cachep
,
1623 size_t size
, size_t align
, unsigned long flags
)
1625 size_t left_over
= 0;
1627 for (;; cachep
->gfporder
++) {
1631 if (cachep
->gfporder
> MAX_GFP_ORDER
) {
1636 cache_estimate(cachep
->gfporder
, size
, align
, flags
,
1640 /* More than offslab_limit objects will cause problems */
1641 if (flags
& CFLGS_OFF_SLAB
&& cachep
->num
> offslab_limit
)
1645 left_over
= remainder
;
1648 * Large number of objects is good, but very large slabs are
1649 * currently bad for the gfp()s.
1651 if (cachep
->gfporder
>= slab_break_gfp_order
)
1654 if ((left_over
* 8) <= (PAGE_SIZE
<< cachep
->gfporder
))
1655 /* Acceptable internal fragmentation */
1662 * kmem_cache_create - Create a cache.
1663 * @name: A string which is used in /proc/slabinfo to identify this cache.
1664 * @size: The size of objects to be created in this cache.
1665 * @align: The required alignment for the objects.
1666 * @flags: SLAB flags
1667 * @ctor: A constructor for the objects.
1668 * @dtor: A destructor for the objects.
1670 * Returns a ptr to the cache on success, NULL on failure.
1671 * Cannot be called within a int, but can be interrupted.
1672 * The @ctor is run when new pages are allocated by the cache
1673 * and the @dtor is run before the pages are handed back.
1675 * @name must be valid until the cache is destroyed. This implies that
1676 * the module calling this has to destroy the cache before getting
1681 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
1682 * to catch references to uninitialised memory.
1684 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
1685 * for buffer overruns.
1687 * %SLAB_NO_REAP - Don't automatically reap this cache when we're under
1690 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
1691 * cacheline. This can be beneficial if you're counting cycles as closely
1695 kmem_cache_create (const char *name
, size_t size
, size_t align
,
1696 unsigned long flags
, void (*ctor
)(void*, struct kmem_cache
*, unsigned long),
1697 void (*dtor
)(void*, struct kmem_cache
*, unsigned long))
1699 size_t left_over
, slab_size
, ralign
;
1700 struct kmem_cache
*cachep
= NULL
;
1701 struct list_head
*p
;
1704 * Sanity checks... these are all serious usage bugs.
1708 (size
< BYTES_PER_WORD
) ||
1709 (size
> (1 << MAX_OBJ_ORDER
) * PAGE_SIZE
) || (dtor
&& !ctor
)) {
1710 printk(KERN_ERR
"%s: Early error in slab %s\n",
1711 __FUNCTION__
, name
);
1715 mutex_lock(&cache_chain_mutex
);
1717 list_for_each(p
, &cache_chain
) {
1718 struct kmem_cache
*pc
= list_entry(p
, struct kmem_cache
, next
);
1719 mm_segment_t old_fs
= get_fs();
1724 * This happens when the module gets unloaded and doesn't
1725 * destroy its slab cache and no-one else reuses the vmalloc
1726 * area of the module. Print a warning.
1729 res
= __get_user(tmp
, pc
->name
);
1732 printk("SLAB: cache with size %d has lost its name\n",
1737 if (!strcmp(pc
->name
, name
)) {
1738 printk("kmem_cache_create: duplicate cache %s\n", name
);
1745 WARN_ON(strchr(name
, ' ')); /* It confuses parsers */
1746 if ((flags
& SLAB_DEBUG_INITIAL
) && !ctor
) {
1747 /* No constructor, but inital state check requested */
1748 printk(KERN_ERR
"%s: No con, but init state check "
1749 "requested - %s\n", __FUNCTION__
, name
);
1750 flags
&= ~SLAB_DEBUG_INITIAL
;
1754 * Enable redzoning and last user accounting, except for caches with
1755 * large objects, if the increased size would increase the object size
1756 * above the next power of two: caches with object sizes just above a
1757 * power of two have a significant amount of internal fragmentation.
1760 || fls(size
- 1) == fls(size
- 1 + 3 * BYTES_PER_WORD
)))
1761 flags
|= SLAB_RED_ZONE
| SLAB_STORE_USER
;
1762 if (!(flags
& SLAB_DESTROY_BY_RCU
))
1763 flags
|= SLAB_POISON
;
1765 if (flags
& SLAB_DESTROY_BY_RCU
)
1766 BUG_ON(flags
& SLAB_POISON
);
1768 if (flags
& SLAB_DESTROY_BY_RCU
)
1772 * Always checks flags, a caller might be expecting debug
1773 * support which isn't available.
1775 if (flags
& ~CREATE_MASK
)
1778 /* Check that size is in terms of words. This is needed to avoid
1779 * unaligned accesses for some archs when redzoning is used, and makes
1780 * sure any on-slab bufctl's are also correctly aligned.
1782 if (size
& (BYTES_PER_WORD
- 1)) {
1783 size
+= (BYTES_PER_WORD
- 1);
1784 size
&= ~(BYTES_PER_WORD
- 1);
1787 /* calculate out the final buffer alignment: */
1788 /* 1) arch recommendation: can be overridden for debug */
1789 if (flags
& SLAB_HWCACHE_ALIGN
) {
1790 /* Default alignment: as specified by the arch code.
1791 * Except if an object is really small, then squeeze multiple
1792 * objects into one cacheline.
1794 ralign
= cache_line_size();
1795 while (size
<= ralign
/ 2)
1798 ralign
= BYTES_PER_WORD
;
1800 /* 2) arch mandated alignment: disables debug if necessary */
1801 if (ralign
< ARCH_SLAB_MINALIGN
) {
1802 ralign
= ARCH_SLAB_MINALIGN
;
1803 if (ralign
> BYTES_PER_WORD
)
1804 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
1806 /* 3) caller mandated alignment: disables debug if necessary */
1807 if (ralign
< align
) {
1809 if (ralign
> BYTES_PER_WORD
)
1810 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
1812 /* 4) Store it. Note that the debug code below can reduce
1813 * the alignment to BYTES_PER_WORD.
1817 /* Get cache's description obj. */
1818 cachep
= kmem_cache_alloc(&cache_cache
, SLAB_KERNEL
);
1821 memset(cachep
, 0, sizeof(struct kmem_cache
));
1824 cachep
->obj_size
= size
;
1826 if (flags
& SLAB_RED_ZONE
) {
1827 /* redzoning only works with word aligned caches */
1828 align
= BYTES_PER_WORD
;
1830 /* add space for red zone words */
1831 cachep
->obj_offset
+= BYTES_PER_WORD
;
1832 size
+= 2 * BYTES_PER_WORD
;
1834 if (flags
& SLAB_STORE_USER
) {
1835 /* user store requires word alignment and
1836 * one word storage behind the end of the real
1839 align
= BYTES_PER_WORD
;
1840 size
+= BYTES_PER_WORD
;
1842 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
1843 if (size
>= malloc_sizes
[INDEX_L3
+ 1].cs_size
1844 && cachep
->obj_size
> cache_line_size() && size
< PAGE_SIZE
) {
1845 cachep
->obj_offset
+= PAGE_SIZE
- size
;
1851 /* Determine if the slab management is 'on' or 'off' slab. */
1852 if (size
>= (PAGE_SIZE
>> 3))
1854 * Size is large, assume best to place the slab management obj
1855 * off-slab (should allow better packing of objs).
1857 flags
|= CFLGS_OFF_SLAB
;
1859 size
= ALIGN(size
, align
);
1861 if ((flags
& SLAB_RECLAIM_ACCOUNT
) && size
<= PAGE_SIZE
) {
1863 * A VFS-reclaimable slab tends to have most allocations
1864 * as GFP_NOFS and we really don't want to have to be allocating
1865 * higher-order pages when we are unable to shrink dcache.
1867 cachep
->gfporder
= 0;
1868 cache_estimate(cachep
->gfporder
, size
, align
, flags
,
1869 &left_over
, &cachep
->num
);
1871 left_over
= calculate_slab_order(cachep
, size
, align
, flags
);
1874 printk("kmem_cache_create: couldn't create cache %s.\n", name
);
1875 kmem_cache_free(&cache_cache
, cachep
);
1879 slab_size
= ALIGN(cachep
->num
* sizeof(kmem_bufctl_t
)
1880 + sizeof(struct slab
), align
);
1883 * If the slab has been placed off-slab, and we have enough space then
1884 * move it on-slab. This is at the expense of any extra colouring.
1886 if (flags
& CFLGS_OFF_SLAB
&& left_over
>= slab_size
) {
1887 flags
&= ~CFLGS_OFF_SLAB
;
1888 left_over
-= slab_size
;
1891 if (flags
& CFLGS_OFF_SLAB
) {
1892 /* really off slab. No need for manual alignment */
1894 cachep
->num
* sizeof(kmem_bufctl_t
) + sizeof(struct slab
);
1897 cachep
->colour_off
= cache_line_size();
1898 /* Offset must be a multiple of the alignment. */
1899 if (cachep
->colour_off
< align
)
1900 cachep
->colour_off
= align
;
1901 cachep
->colour
= left_over
/ cachep
->colour_off
;
1902 cachep
->slab_size
= slab_size
;
1903 cachep
->flags
= flags
;
1904 cachep
->gfpflags
= 0;
1905 if (flags
& SLAB_CACHE_DMA
)
1906 cachep
->gfpflags
|= GFP_DMA
;
1907 spin_lock_init(&cachep
->spinlock
);
1908 cachep
->buffer_size
= size
;
1910 if (flags
& CFLGS_OFF_SLAB
)
1911 cachep
->slabp_cache
= kmem_find_general_cachep(slab_size
, 0u);
1912 cachep
->ctor
= ctor
;
1913 cachep
->dtor
= dtor
;
1914 cachep
->name
= name
;
1916 /* Don't let CPUs to come and go */
1919 if (g_cpucache_up
== FULL
) {
1920 enable_cpucache(cachep
);
1922 if (g_cpucache_up
== NONE
) {
1923 /* Note: the first kmem_cache_create must create
1924 * the cache that's used by kmalloc(24), otherwise
1925 * the creation of further caches will BUG().
1927 cachep
->array
[smp_processor_id()] =
1928 &initarray_generic
.cache
;
1930 /* If the cache that's used by
1931 * kmalloc(sizeof(kmem_list3)) is the first cache,
1932 * then we need to set up all its list3s, otherwise
1933 * the creation of further caches will BUG().
1935 set_up_list3s(cachep
, SIZE_AC
);
1936 if (INDEX_AC
== INDEX_L3
)
1937 g_cpucache_up
= PARTIAL_L3
;
1939 g_cpucache_up
= PARTIAL_AC
;
1941 cachep
->array
[smp_processor_id()] =
1942 kmalloc(sizeof(struct arraycache_init
), GFP_KERNEL
);
1944 if (g_cpucache_up
== PARTIAL_AC
) {
1945 set_up_list3s(cachep
, SIZE_L3
);
1946 g_cpucache_up
= PARTIAL_L3
;
1949 for_each_online_node(node
) {
1951 cachep
->nodelists
[node
] =
1953 (struct kmem_list3
),
1955 BUG_ON(!cachep
->nodelists
[node
]);
1956 kmem_list3_init(cachep
->
1961 cachep
->nodelists
[numa_node_id()]->next_reap
=
1962 jiffies
+ REAPTIMEOUT_LIST3
+
1963 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
1965 BUG_ON(!cpu_cache_get(cachep
));
1966 cpu_cache_get(cachep
)->avail
= 0;
1967 cpu_cache_get(cachep
)->limit
= BOOT_CPUCACHE_ENTRIES
;
1968 cpu_cache_get(cachep
)->batchcount
= 1;
1969 cpu_cache_get(cachep
)->touched
= 0;
1970 cachep
->batchcount
= 1;
1971 cachep
->limit
= BOOT_CPUCACHE_ENTRIES
;
1974 /* cache setup completed, link it into the list */
1975 list_add(&cachep
->next
, &cache_chain
);
1976 unlock_cpu_hotplug();
1978 if (!cachep
&& (flags
& SLAB_PANIC
))
1979 panic("kmem_cache_create(): failed to create slab `%s'\n",
1981 mutex_unlock(&cache_chain_mutex
);
1984 EXPORT_SYMBOL(kmem_cache_create
);
1987 static void check_irq_off(void)
1989 BUG_ON(!irqs_disabled());
1992 static void check_irq_on(void)
1994 BUG_ON(irqs_disabled());
1997 static void check_spinlock_acquired(struct kmem_cache
*cachep
)
2001 assert_spin_locked(&cachep
->nodelists
[numa_node_id()]->list_lock
);
2005 static void check_spinlock_acquired_node(struct kmem_cache
*cachep
, int node
)
2009 assert_spin_locked(&cachep
->nodelists
[node
]->list_lock
);
2014 #define check_irq_off() do { } while(0)
2015 #define check_irq_on() do { } while(0)
2016 #define check_spinlock_acquired(x) do { } while(0)
2017 #define check_spinlock_acquired_node(x, y) do { } while(0)
2021 * Waits for all CPUs to execute func().
2023 static void smp_call_function_all_cpus(void (*func
)(void *arg
), void *arg
)
2028 local_irq_disable();
2032 if (smp_call_function(func
, arg
, 1, 1))
2038 static void drain_array_locked(struct kmem_cache
*cachep
, struct array_cache
*ac
,
2039 int force
, int node
);
2041 static void do_drain(void *arg
)
2043 struct kmem_cache
*cachep
= (struct kmem_cache
*) arg
;
2044 struct array_cache
*ac
;
2045 int node
= numa_node_id();
2048 ac
= cpu_cache_get(cachep
);
2049 spin_lock(&cachep
->nodelists
[node
]->list_lock
);
2050 free_block(cachep
, ac
->entry
, ac
->avail
, node
);
2051 spin_unlock(&cachep
->nodelists
[node
]->list_lock
);
2055 static void drain_cpu_caches(struct kmem_cache
*cachep
)
2057 struct kmem_list3
*l3
;
2060 smp_call_function_all_cpus(do_drain
, cachep
);
2062 for_each_online_node(node
) {
2063 l3
= cachep
->nodelists
[node
];
2065 spin_lock_irq(&l3
->list_lock
);
2066 drain_array_locked(cachep
, l3
->shared
, 1, node
);
2067 spin_unlock_irq(&l3
->list_lock
);
2069 drain_alien_cache(cachep
, l3
->alien
);
2074 static int __node_shrink(struct kmem_cache
*cachep
, int node
)
2077 struct kmem_list3
*l3
= cachep
->nodelists
[node
];
2081 struct list_head
*p
;
2083 p
= l3
->slabs_free
.prev
;
2084 if (p
== &l3
->slabs_free
)
2087 slabp
= list_entry(l3
->slabs_free
.prev
, struct slab
, list
);
2092 list_del(&slabp
->list
);
2094 l3
->free_objects
-= cachep
->num
;
2095 spin_unlock_irq(&l3
->list_lock
);
2096 slab_destroy(cachep
, slabp
);
2097 spin_lock_irq(&l3
->list_lock
);
2099 ret
= !list_empty(&l3
->slabs_full
) || !list_empty(&l3
->slabs_partial
);
2103 static int __cache_shrink(struct kmem_cache
*cachep
)
2106 struct kmem_list3
*l3
;
2108 drain_cpu_caches(cachep
);
2111 for_each_online_node(i
) {
2112 l3
= cachep
->nodelists
[i
];
2114 spin_lock_irq(&l3
->list_lock
);
2115 ret
+= __node_shrink(cachep
, i
);
2116 spin_unlock_irq(&l3
->list_lock
);
2119 return (ret
? 1 : 0);
2123 * kmem_cache_shrink - Shrink a cache.
2124 * @cachep: The cache to shrink.
2126 * Releases as many slabs as possible for a cache.
2127 * To help debugging, a zero exit status indicates all slabs were released.
2129 int kmem_cache_shrink(struct kmem_cache
*cachep
)
2131 if (!cachep
|| in_interrupt())
2134 return __cache_shrink(cachep
);
2136 EXPORT_SYMBOL(kmem_cache_shrink
);
2139 * kmem_cache_destroy - delete a cache
2140 * @cachep: the cache to destroy
2142 * Remove a struct kmem_cache object from the slab cache.
2143 * Returns 0 on success.
2145 * It is expected this function will be called by a module when it is
2146 * unloaded. This will remove the cache completely, and avoid a duplicate
2147 * cache being allocated each time a module is loaded and unloaded, if the
2148 * module doesn't have persistent in-kernel storage across loads and unloads.
2150 * The cache must be empty before calling this function.
2152 * The caller must guarantee that noone will allocate memory from the cache
2153 * during the kmem_cache_destroy().
2155 int kmem_cache_destroy(struct kmem_cache
*cachep
)
2158 struct kmem_list3
*l3
;
2160 if (!cachep
|| in_interrupt())
2163 /* Don't let CPUs to come and go */
2166 /* Find the cache in the chain of caches. */
2167 mutex_lock(&cache_chain_mutex
);
2169 * the chain is never empty, cache_cache is never destroyed
2171 list_del(&cachep
->next
);
2172 mutex_unlock(&cache_chain_mutex
);
2174 if (__cache_shrink(cachep
)) {
2175 slab_error(cachep
, "Can't free all objects");
2176 mutex_lock(&cache_chain_mutex
);
2177 list_add(&cachep
->next
, &cache_chain
);
2178 mutex_unlock(&cache_chain_mutex
);
2179 unlock_cpu_hotplug();
2183 if (unlikely(cachep
->flags
& SLAB_DESTROY_BY_RCU
))
2186 for_each_online_cpu(i
)
2187 kfree(cachep
->array
[i
]);
2189 /* NUMA: free the list3 structures */
2190 for_each_online_node(i
) {
2191 if ((l3
= cachep
->nodelists
[i
])) {
2193 free_alien_cache(l3
->alien
);
2197 kmem_cache_free(&cache_cache
, cachep
);
2199 unlock_cpu_hotplug();
2203 EXPORT_SYMBOL(kmem_cache_destroy
);
2205 /* Get the memory for a slab management obj. */
2206 static struct slab
*alloc_slabmgmt(struct kmem_cache
*cachep
, void *objp
,
2207 int colour_off
, gfp_t local_flags
)
2211 if (OFF_SLAB(cachep
)) {
2212 /* Slab management obj is off-slab. */
2213 slabp
= kmem_cache_alloc(cachep
->slabp_cache
, local_flags
);
2217 slabp
= objp
+ colour_off
;
2218 colour_off
+= cachep
->slab_size
;
2221 slabp
->colouroff
= colour_off
;
2222 slabp
->s_mem
= objp
+ colour_off
;
2227 static inline kmem_bufctl_t
*slab_bufctl(struct slab
*slabp
)
2229 return (kmem_bufctl_t
*) (slabp
+ 1);
2232 static void cache_init_objs(struct kmem_cache
*cachep
,
2233 struct slab
*slabp
, unsigned long ctor_flags
)
2237 for (i
= 0; i
< cachep
->num
; i
++) {
2238 void *objp
= slabp
->s_mem
+ cachep
->buffer_size
* i
;
2240 /* need to poison the objs? */
2241 if (cachep
->flags
& SLAB_POISON
)
2242 poison_obj(cachep
, objp
, POISON_FREE
);
2243 if (cachep
->flags
& SLAB_STORE_USER
)
2244 *dbg_userword(cachep
, objp
) = NULL
;
2246 if (cachep
->flags
& SLAB_RED_ZONE
) {
2247 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2248 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2251 * Constructors are not allowed to allocate memory from
2252 * the same cache which they are a constructor for.
2253 * Otherwise, deadlock. They must also be threaded.
2255 if (cachep
->ctor
&& !(cachep
->flags
& SLAB_POISON
))
2256 cachep
->ctor(objp
+ obj_offset(cachep
), cachep
,
2259 if (cachep
->flags
& SLAB_RED_ZONE
) {
2260 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
2261 slab_error(cachep
, "constructor overwrote the"
2262 " end of an object");
2263 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
2264 slab_error(cachep
, "constructor overwrote the"
2265 " start of an object");
2267 if ((cachep
->buffer_size
% PAGE_SIZE
) == 0 && OFF_SLAB(cachep
)
2268 && cachep
->flags
& SLAB_POISON
)
2269 kernel_map_pages(virt_to_page(objp
),
2270 cachep
->buffer_size
/ PAGE_SIZE
, 0);
2273 cachep
->ctor(objp
, cachep
, ctor_flags
);
2275 slab_bufctl(slabp
)[i
] = i
+ 1;
2277 slab_bufctl(slabp
)[i
- 1] = BUFCTL_END
;
2281 static void kmem_flagcheck(struct kmem_cache
*cachep
, gfp_t flags
)
2283 if (flags
& SLAB_DMA
) {
2284 if (!(cachep
->gfpflags
& GFP_DMA
))
2287 if (cachep
->gfpflags
& GFP_DMA
)
2292 static void *slab_get_obj(struct kmem_cache
*cachep
, struct slab
*slabp
, int nodeid
)
2294 void *objp
= slabp
->s_mem
+ (slabp
->free
* cachep
->buffer_size
);
2298 next
= slab_bufctl(slabp
)[slabp
->free
];
2300 slab_bufctl(slabp
)[slabp
->free
] = BUFCTL_FREE
;
2301 WARN_ON(slabp
->nodeid
!= nodeid
);
2308 static void slab_put_obj(struct kmem_cache
*cachep
, struct slab
*slabp
, void *objp
,
2311 unsigned int objnr
= (unsigned)(objp
-slabp
->s_mem
) / cachep
->buffer_size
;
2314 /* Verify that the slab belongs to the intended node */
2315 WARN_ON(slabp
->nodeid
!= nodeid
);
2317 if (slab_bufctl(slabp
)[objnr
] != BUFCTL_FREE
) {
2318 printk(KERN_ERR
"slab: double free detected in cache "
2319 "'%s', objp %p\n", cachep
->name
, objp
);
2323 slab_bufctl(slabp
)[objnr
] = slabp
->free
;
2324 slabp
->free
= objnr
;
2328 static void set_slab_attr(struct kmem_cache
*cachep
, struct slab
*slabp
, void *objp
)
2333 /* Nasty!!!!!! I hope this is OK. */
2334 i
= 1 << cachep
->gfporder
;
2335 page
= virt_to_page(objp
);
2337 page_set_cache(page
, cachep
);
2338 page_set_slab(page
, slabp
);
2344 * Grow (by 1) the number of slabs within a cache. This is called by
2345 * kmem_cache_alloc() when there are no active objs left in a cache.
2347 static int cache_grow(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
2353 unsigned long ctor_flags
;
2354 struct kmem_list3
*l3
;
2356 /* Be lazy and only check for valid flags here,
2357 * keeping it out of the critical path in kmem_cache_alloc().
2359 if (flags
& ~(SLAB_DMA
| SLAB_LEVEL_MASK
| SLAB_NO_GROW
))
2361 if (flags
& SLAB_NO_GROW
)
2364 ctor_flags
= SLAB_CTOR_CONSTRUCTOR
;
2365 local_flags
= (flags
& SLAB_LEVEL_MASK
);
2366 if (!(local_flags
& __GFP_WAIT
))
2368 * Not allowed to sleep. Need to tell a constructor about
2369 * this - it might need to know...
2371 ctor_flags
|= SLAB_CTOR_ATOMIC
;
2373 /* Take the l3 list lock to change the colour_next on this node */
2375 l3
= cachep
->nodelists
[nodeid
];
2376 spin_lock(&l3
->list_lock
);
2378 /* Get colour for the slab, and cal the next value. */
2379 offset
= l3
->colour_next
;
2381 if (l3
->colour_next
>= cachep
->colour
)
2382 l3
->colour_next
= 0;
2383 spin_unlock(&l3
->list_lock
);
2385 offset
*= cachep
->colour_off
;
2387 if (local_flags
& __GFP_WAIT
)
2391 * The test for missing atomic flag is performed here, rather than
2392 * the more obvious place, simply to reduce the critical path length
2393 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2394 * will eventually be caught here (where it matters).
2396 kmem_flagcheck(cachep
, flags
);
2398 /* Get mem for the objs.
2399 * Attempt to allocate a physical page from 'nodeid',
2401 if (!(objp
= kmem_getpages(cachep
, flags
, nodeid
)))
2404 /* Get slab management. */
2405 if (!(slabp
= alloc_slabmgmt(cachep
, objp
, offset
, local_flags
)))
2408 slabp
->nodeid
= nodeid
;
2409 set_slab_attr(cachep
, slabp
, objp
);
2411 cache_init_objs(cachep
, slabp
, ctor_flags
);
2413 if (local_flags
& __GFP_WAIT
)
2414 local_irq_disable();
2416 spin_lock(&l3
->list_lock
);
2418 /* Make slab active. */
2419 list_add_tail(&slabp
->list
, &(l3
->slabs_free
));
2420 STATS_INC_GROWN(cachep
);
2421 l3
->free_objects
+= cachep
->num
;
2422 spin_unlock(&l3
->list_lock
);
2425 kmem_freepages(cachep
, objp
);
2427 if (local_flags
& __GFP_WAIT
)
2428 local_irq_disable();
2435 * Perform extra freeing checks:
2436 * - detect bad pointers.
2437 * - POISON/RED_ZONE checking
2438 * - destructor calls, for caches with POISON+dtor
2440 static void kfree_debugcheck(const void *objp
)
2444 if (!virt_addr_valid(objp
)) {
2445 printk(KERN_ERR
"kfree_debugcheck: out of range ptr %lxh.\n",
2446 (unsigned long)objp
);
2449 page
= virt_to_page(objp
);
2450 if (!PageSlab(page
)) {
2451 printk(KERN_ERR
"kfree_debugcheck: bad ptr %lxh.\n",
2452 (unsigned long)objp
);
2457 static void *cache_free_debugcheck(struct kmem_cache
*cachep
, void *objp
,
2464 objp
-= obj_offset(cachep
);
2465 kfree_debugcheck(objp
);
2466 page
= virt_to_page(objp
);
2468 if (page_get_cache(page
) != cachep
) {
2470 "mismatch in kmem_cache_free: expected cache %p, got %p\n",
2471 page_get_cache(page
), cachep
);
2472 printk(KERN_ERR
"%p is %s.\n", cachep
, cachep
->name
);
2473 printk(KERN_ERR
"%p is %s.\n", page_get_cache(page
),
2474 page_get_cache(page
)->name
);
2477 slabp
= page_get_slab(page
);
2479 if (cachep
->flags
& SLAB_RED_ZONE
) {
2480 if (*dbg_redzone1(cachep
, objp
) != RED_ACTIVE
2481 || *dbg_redzone2(cachep
, objp
) != RED_ACTIVE
) {
2483 "double free, or memory outside"
2484 " object was overwritten");
2486 "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n",
2487 objp
, *dbg_redzone1(cachep
, objp
),
2488 *dbg_redzone2(cachep
, objp
));
2490 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2491 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2493 if (cachep
->flags
& SLAB_STORE_USER
)
2494 *dbg_userword(cachep
, objp
) = caller
;
2496 objnr
= (unsigned)(objp
- slabp
->s_mem
) / cachep
->buffer_size
;
2498 BUG_ON(objnr
>= cachep
->num
);
2499 BUG_ON(objp
!= slabp
->s_mem
+ objnr
* cachep
->buffer_size
);
2501 if (cachep
->flags
& SLAB_DEBUG_INITIAL
) {
2502 /* Need to call the slab's constructor so the
2503 * caller can perform a verify of its state (debugging).
2504 * Called without the cache-lock held.
2506 cachep
->ctor(objp
+ obj_offset(cachep
),
2507 cachep
, SLAB_CTOR_CONSTRUCTOR
| SLAB_CTOR_VERIFY
);
2509 if (cachep
->flags
& SLAB_POISON
&& cachep
->dtor
) {
2510 /* we want to cache poison the object,
2511 * call the destruction callback
2513 cachep
->dtor(objp
+ obj_offset(cachep
), cachep
, 0);
2515 if (cachep
->flags
& SLAB_POISON
) {
2516 #ifdef CONFIG_DEBUG_PAGEALLOC
2517 if ((cachep
->buffer_size
% PAGE_SIZE
) == 0 && OFF_SLAB(cachep
)) {
2518 store_stackinfo(cachep
, objp
, (unsigned long)caller
);
2519 kernel_map_pages(virt_to_page(objp
),
2520 cachep
->buffer_size
/ PAGE_SIZE
, 0);
2522 poison_obj(cachep
, objp
, POISON_FREE
);
2525 poison_obj(cachep
, objp
, POISON_FREE
);
2531 static void check_slabp(struct kmem_cache
*cachep
, struct slab
*slabp
)
2536 /* Check slab's freelist to see if this obj is there. */
2537 for (i
= slabp
->free
; i
!= BUFCTL_END
; i
= slab_bufctl(slabp
)[i
]) {
2539 if (entries
> cachep
->num
|| i
>= cachep
->num
)
2542 if (entries
!= cachep
->num
- slabp
->inuse
) {
2545 "slab: Internal list corruption detected in cache '%s'(%d), slabp %p(%d). Hexdump:\n",
2546 cachep
->name
, cachep
->num
, slabp
, slabp
->inuse
);
2548 i
< sizeof(slabp
) + cachep
->num
* sizeof(kmem_bufctl_t
);
2551 printk("\n%03x:", i
);
2552 printk(" %02x", ((unsigned char *)slabp
)[i
]);
2559 #define kfree_debugcheck(x) do { } while(0)
2560 #define cache_free_debugcheck(x,objp,z) (objp)
2561 #define check_slabp(x,y) do { } while(0)
2564 static void *cache_alloc_refill(struct kmem_cache
*cachep
, gfp_t flags
)
2567 struct kmem_list3
*l3
;
2568 struct array_cache
*ac
;
2571 ac
= cpu_cache_get(cachep
);
2573 batchcount
= ac
->batchcount
;
2574 if (!ac
->touched
&& batchcount
> BATCHREFILL_LIMIT
) {
2575 /* if there was little recent activity on this
2576 * cache, then perform only a partial refill.
2577 * Otherwise we could generate refill bouncing.
2579 batchcount
= BATCHREFILL_LIMIT
;
2581 l3
= cachep
->nodelists
[numa_node_id()];
2583 BUG_ON(ac
->avail
> 0 || !l3
);
2584 spin_lock(&l3
->list_lock
);
2587 struct array_cache
*shared_array
= l3
->shared
;
2588 if (shared_array
->avail
) {
2589 if (batchcount
> shared_array
->avail
)
2590 batchcount
= shared_array
->avail
;
2591 shared_array
->avail
-= batchcount
;
2592 ac
->avail
= batchcount
;
2594 &(shared_array
->entry
[shared_array
->avail
]),
2595 sizeof(void *) * batchcount
);
2596 shared_array
->touched
= 1;
2600 while (batchcount
> 0) {
2601 struct list_head
*entry
;
2603 /* Get slab alloc is to come from. */
2604 entry
= l3
->slabs_partial
.next
;
2605 if (entry
== &l3
->slabs_partial
) {
2606 l3
->free_touched
= 1;
2607 entry
= l3
->slabs_free
.next
;
2608 if (entry
== &l3
->slabs_free
)
2612 slabp
= list_entry(entry
, struct slab
, list
);
2613 check_slabp(cachep
, slabp
);
2614 check_spinlock_acquired(cachep
);
2615 while (slabp
->inuse
< cachep
->num
&& batchcount
--) {
2616 STATS_INC_ALLOCED(cachep
);
2617 STATS_INC_ACTIVE(cachep
);
2618 STATS_SET_HIGH(cachep
);
2620 ac
->entry
[ac
->avail
++] = slab_get_obj(cachep
, slabp
,
2623 check_slabp(cachep
, slabp
);
2625 /* move slabp to correct slabp list: */
2626 list_del(&slabp
->list
);
2627 if (slabp
->free
== BUFCTL_END
)
2628 list_add(&slabp
->list
, &l3
->slabs_full
);
2630 list_add(&slabp
->list
, &l3
->slabs_partial
);
2634 l3
->free_objects
-= ac
->avail
;
2636 spin_unlock(&l3
->list_lock
);
2638 if (unlikely(!ac
->avail
)) {
2640 x
= cache_grow(cachep
, flags
, numa_node_id());
2642 // cache_grow can reenable interrupts, then ac could change.
2643 ac
= cpu_cache_get(cachep
);
2644 if (!x
&& ac
->avail
== 0) // no objects in sight? abort
2647 if (!ac
->avail
) // objects refilled by interrupt?
2651 return ac
->entry
[--ac
->avail
];
2655 cache_alloc_debugcheck_before(struct kmem_cache
*cachep
, gfp_t flags
)
2657 might_sleep_if(flags
& __GFP_WAIT
);
2659 kmem_flagcheck(cachep
, flags
);
2664 static void *cache_alloc_debugcheck_after(struct kmem_cache
*cachep
, gfp_t flags
,
2665 void *objp
, void *caller
)
2669 if (cachep
->flags
& SLAB_POISON
) {
2670 #ifdef CONFIG_DEBUG_PAGEALLOC
2671 if ((cachep
->buffer_size
% PAGE_SIZE
) == 0 && OFF_SLAB(cachep
))
2672 kernel_map_pages(virt_to_page(objp
),
2673 cachep
->buffer_size
/ PAGE_SIZE
, 1);
2675 check_poison_obj(cachep
, objp
);
2677 check_poison_obj(cachep
, objp
);
2679 poison_obj(cachep
, objp
, POISON_INUSE
);
2681 if (cachep
->flags
& SLAB_STORE_USER
)
2682 *dbg_userword(cachep
, objp
) = caller
;
2684 if (cachep
->flags
& SLAB_RED_ZONE
) {
2685 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
2686 || *dbg_redzone2(cachep
, objp
) != RED_INACTIVE
) {
2688 "double free, or memory outside"
2689 " object was overwritten");
2691 "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n",
2692 objp
, *dbg_redzone1(cachep
, objp
),
2693 *dbg_redzone2(cachep
, objp
));
2695 *dbg_redzone1(cachep
, objp
) = RED_ACTIVE
;
2696 *dbg_redzone2(cachep
, objp
) = RED_ACTIVE
;
2698 objp
+= obj_offset(cachep
);
2699 if (cachep
->ctor
&& cachep
->flags
& SLAB_POISON
) {
2700 unsigned long ctor_flags
= SLAB_CTOR_CONSTRUCTOR
;
2702 if (!(flags
& __GFP_WAIT
))
2703 ctor_flags
|= SLAB_CTOR_ATOMIC
;
2705 cachep
->ctor(objp
, cachep
, ctor_flags
);
2710 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
2713 static inline void *____cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
2716 struct array_cache
*ac
;
2719 if (unlikely(current
->mempolicy
&& !in_interrupt())) {
2720 int nid
= slab_node(current
->mempolicy
);
2722 if (nid
!= numa_node_id())
2723 return __cache_alloc_node(cachep
, flags
, nid
);
2728 ac
= cpu_cache_get(cachep
);
2729 if (likely(ac
->avail
)) {
2730 STATS_INC_ALLOCHIT(cachep
);
2732 objp
= ac
->entry
[--ac
->avail
];
2734 STATS_INC_ALLOCMISS(cachep
);
2735 objp
= cache_alloc_refill(cachep
, flags
);
2740 static __always_inline
void *
2741 __cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
, void *caller
)
2743 unsigned long save_flags
;
2746 cache_alloc_debugcheck_before(cachep
, flags
);
2748 local_irq_save(save_flags
);
2749 objp
= ____cache_alloc(cachep
, flags
);
2750 local_irq_restore(save_flags
);
2751 objp
= cache_alloc_debugcheck_after(cachep
, flags
, objp
,
2759 * A interface to enable slab creation on nodeid
2761 static void *__cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
2763 struct list_head
*entry
;
2765 struct kmem_list3
*l3
;
2769 l3
= cachep
->nodelists
[nodeid
];
2774 spin_lock(&l3
->list_lock
);
2775 entry
= l3
->slabs_partial
.next
;
2776 if (entry
== &l3
->slabs_partial
) {
2777 l3
->free_touched
= 1;
2778 entry
= l3
->slabs_free
.next
;
2779 if (entry
== &l3
->slabs_free
)
2783 slabp
= list_entry(entry
, struct slab
, list
);
2784 check_spinlock_acquired_node(cachep
, nodeid
);
2785 check_slabp(cachep
, slabp
);
2787 STATS_INC_NODEALLOCS(cachep
);
2788 STATS_INC_ACTIVE(cachep
);
2789 STATS_SET_HIGH(cachep
);
2791 BUG_ON(slabp
->inuse
== cachep
->num
);
2793 obj
= slab_get_obj(cachep
, slabp
, nodeid
);
2794 check_slabp(cachep
, slabp
);
2796 /* move slabp to correct slabp list: */
2797 list_del(&slabp
->list
);
2799 if (slabp
->free
== BUFCTL_END
) {
2800 list_add(&slabp
->list
, &l3
->slabs_full
);
2802 list_add(&slabp
->list
, &l3
->slabs_partial
);
2805 spin_unlock(&l3
->list_lock
);
2809 spin_unlock(&l3
->list_lock
);
2810 x
= cache_grow(cachep
, flags
, nodeid
);
2822 * Caller needs to acquire correct kmem_list's list_lock
2824 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int nr_objects
,
2828 struct kmem_list3
*l3
;
2830 for (i
= 0; i
< nr_objects
; i
++) {
2831 void *objp
= objpp
[i
];
2834 slabp
= virt_to_slab(objp
);
2835 l3
= cachep
->nodelists
[node
];
2836 list_del(&slabp
->list
);
2837 check_spinlock_acquired_node(cachep
, node
);
2838 check_slabp(cachep
, slabp
);
2839 slab_put_obj(cachep
, slabp
, objp
, node
);
2840 STATS_DEC_ACTIVE(cachep
);
2842 check_slabp(cachep
, slabp
);
2844 /* fixup slab chains */
2845 if (slabp
->inuse
== 0) {
2846 if (l3
->free_objects
> l3
->free_limit
) {
2847 l3
->free_objects
-= cachep
->num
;
2848 slab_destroy(cachep
, slabp
);
2850 list_add(&slabp
->list
, &l3
->slabs_free
);
2853 /* Unconditionally move a slab to the end of the
2854 * partial list on free - maximum time for the
2855 * other objects to be freed, too.
2857 list_add_tail(&slabp
->list
, &l3
->slabs_partial
);
2862 static void cache_flusharray(struct kmem_cache
*cachep
, struct array_cache
*ac
)
2865 struct kmem_list3
*l3
;
2866 int node
= numa_node_id();
2868 batchcount
= ac
->batchcount
;
2870 BUG_ON(!batchcount
|| batchcount
> ac
->avail
);
2873 l3
= cachep
->nodelists
[node
];
2874 spin_lock(&l3
->list_lock
);
2876 struct array_cache
*shared_array
= l3
->shared
;
2877 int max
= shared_array
->limit
- shared_array
->avail
;
2879 if (batchcount
> max
)
2881 memcpy(&(shared_array
->entry
[shared_array
->avail
]),
2882 ac
->entry
, sizeof(void *) * batchcount
);
2883 shared_array
->avail
+= batchcount
;
2888 free_block(cachep
, ac
->entry
, batchcount
, node
);
2893 struct list_head
*p
;
2895 p
= l3
->slabs_free
.next
;
2896 while (p
!= &(l3
->slabs_free
)) {
2899 slabp
= list_entry(p
, struct slab
, list
);
2900 BUG_ON(slabp
->inuse
);
2905 STATS_SET_FREEABLE(cachep
, i
);
2908 spin_unlock(&l3
->list_lock
);
2909 ac
->avail
-= batchcount
;
2910 memmove(ac
->entry
, &(ac
->entry
[batchcount
]),
2911 sizeof(void *) * ac
->avail
);
2916 * Release an obj back to its cache. If the obj has a constructed
2917 * state, it must be in this state _before_ it is released.
2919 * Called with disabled ints.
2921 static inline void __cache_free(struct kmem_cache
*cachep
, void *objp
)
2923 struct array_cache
*ac
= cpu_cache_get(cachep
);
2926 objp
= cache_free_debugcheck(cachep
, objp
, __builtin_return_address(0));
2928 /* Make sure we are not freeing a object from another
2929 * node to the array cache on this cpu.
2934 slabp
= virt_to_slab(objp
);
2935 if (unlikely(slabp
->nodeid
!= numa_node_id())) {
2936 struct array_cache
*alien
= NULL
;
2937 int nodeid
= slabp
->nodeid
;
2938 struct kmem_list3
*l3
=
2939 cachep
->nodelists
[numa_node_id()];
2941 STATS_INC_NODEFREES(cachep
);
2942 if (l3
->alien
&& l3
->alien
[nodeid
]) {
2943 alien
= l3
->alien
[nodeid
];
2944 spin_lock(&alien
->lock
);
2945 if (unlikely(alien
->avail
== alien
->limit
))
2946 __drain_alien_cache(cachep
,
2948 alien
->entry
[alien
->avail
++] = objp
;
2949 spin_unlock(&alien
->lock
);
2951 spin_lock(&(cachep
->nodelists
[nodeid
])->
2953 free_block(cachep
, &objp
, 1, nodeid
);
2954 spin_unlock(&(cachep
->nodelists
[nodeid
])->
2961 if (likely(ac
->avail
< ac
->limit
)) {
2962 STATS_INC_FREEHIT(cachep
);
2963 ac
->entry
[ac
->avail
++] = objp
;
2966 STATS_INC_FREEMISS(cachep
);
2967 cache_flusharray(cachep
, ac
);
2968 ac
->entry
[ac
->avail
++] = objp
;
2973 * kmem_cache_alloc - Allocate an object
2974 * @cachep: The cache to allocate from.
2975 * @flags: See kmalloc().
2977 * Allocate an object from this cache. The flags are only relevant
2978 * if the cache has no available objects.
2980 void *kmem_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
2982 return __cache_alloc(cachep
, flags
, __builtin_return_address(0));
2984 EXPORT_SYMBOL(kmem_cache_alloc
);
2987 * kmem_ptr_validate - check if an untrusted pointer might
2989 * @cachep: the cache we're checking against
2990 * @ptr: pointer to validate
2992 * This verifies that the untrusted pointer looks sane:
2993 * it is _not_ a guarantee that the pointer is actually
2994 * part of the slab cache in question, but it at least
2995 * validates that the pointer can be dereferenced and
2996 * looks half-way sane.
2998 * Currently only used for dentry validation.
3000 int fastcall
kmem_ptr_validate(struct kmem_cache
*cachep
, void *ptr
)
3002 unsigned long addr
= (unsigned long)ptr
;
3003 unsigned long min_addr
= PAGE_OFFSET
;
3004 unsigned long align_mask
= BYTES_PER_WORD
- 1;
3005 unsigned long size
= cachep
->buffer_size
;
3008 if (unlikely(addr
< min_addr
))
3010 if (unlikely(addr
> (unsigned long)high_memory
- size
))
3012 if (unlikely(addr
& align_mask
))
3014 if (unlikely(!kern_addr_valid(addr
)))
3016 if (unlikely(!kern_addr_valid(addr
+ size
- 1)))
3018 page
= virt_to_page(ptr
);
3019 if (unlikely(!PageSlab(page
)))
3021 if (unlikely(page_get_cache(page
) != cachep
))
3030 * kmem_cache_alloc_node - Allocate an object on the specified node
3031 * @cachep: The cache to allocate from.
3032 * @flags: See kmalloc().
3033 * @nodeid: node number of the target node.
3035 * Identical to kmem_cache_alloc, except that this function is slow
3036 * and can sleep. And it will allocate memory on the given node, which
3037 * can improve the performance for cpu bound structures.
3038 * New and improved: it will now make sure that the object gets
3039 * put on the correct node list so that there is no false sharing.
3041 void *kmem_cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
3043 unsigned long save_flags
;
3046 cache_alloc_debugcheck_before(cachep
, flags
);
3047 local_irq_save(save_flags
);
3049 if (nodeid
== -1 || nodeid
== numa_node_id() ||
3050 !cachep
->nodelists
[nodeid
])
3051 ptr
= ____cache_alloc(cachep
, flags
);
3053 ptr
= __cache_alloc_node(cachep
, flags
, nodeid
);
3054 local_irq_restore(save_flags
);
3056 ptr
= cache_alloc_debugcheck_after(cachep
, flags
, ptr
,
3057 __builtin_return_address(0));
3061 EXPORT_SYMBOL(kmem_cache_alloc_node
);
3063 void *kmalloc_node(size_t size
, gfp_t flags
, int node
)
3065 struct kmem_cache
*cachep
;
3067 cachep
= kmem_find_general_cachep(size
, flags
);
3068 if (unlikely(cachep
== NULL
))
3070 return kmem_cache_alloc_node(cachep
, flags
, node
);
3072 EXPORT_SYMBOL(kmalloc_node
);
3076 * kmalloc - allocate memory
3077 * @size: how many bytes of memory are required.
3078 * @flags: the type of memory to allocate.
3080 * kmalloc is the normal method of allocating memory
3083 * The @flags argument may be one of:
3085 * %GFP_USER - Allocate memory on behalf of user. May sleep.
3087 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
3089 * %GFP_ATOMIC - Allocation will not sleep. Use inside interrupt handlers.
3091 * Additionally, the %GFP_DMA flag may be set to indicate the memory
3092 * must be suitable for DMA. This can mean different things on different
3093 * platforms. For example, on i386, it means that the memory must come
3094 * from the first 16MB.
3096 static __always_inline
void *__do_kmalloc(size_t size
, gfp_t flags
,
3099 struct kmem_cache
*cachep
;
3101 /* If you want to save a few bytes .text space: replace
3103 * Then kmalloc uses the uninlined functions instead of the inline
3106 cachep
= __find_general_cachep(size
, flags
);
3107 if (unlikely(cachep
== NULL
))
3109 return __cache_alloc(cachep
, flags
, caller
);
3112 #ifndef CONFIG_DEBUG_SLAB
3114 void *__kmalloc(size_t size
, gfp_t flags
)
3116 return __do_kmalloc(size
, flags
, NULL
);
3118 EXPORT_SYMBOL(__kmalloc
);
3122 void *__kmalloc_track_caller(size_t size
, gfp_t flags
, void *caller
)
3124 return __do_kmalloc(size
, flags
, caller
);
3126 EXPORT_SYMBOL(__kmalloc_track_caller
);
3132 * __alloc_percpu - allocate one copy of the object for every present
3133 * cpu in the system, zeroing them.
3134 * Objects should be dereferenced using the per_cpu_ptr macro only.
3136 * @size: how many bytes of memory are required.
3138 void *__alloc_percpu(size_t size
)
3141 struct percpu_data
*pdata
= kmalloc(sizeof(*pdata
), GFP_KERNEL
);
3147 * Cannot use for_each_online_cpu since a cpu may come online
3148 * and we have no way of figuring out how to fix the array
3149 * that we have allocated then....
3152 int node
= cpu_to_node(i
);
3154 if (node_online(node
))
3155 pdata
->ptrs
[i
] = kmalloc_node(size
, GFP_KERNEL
, node
);
3157 pdata
->ptrs
[i
] = kmalloc(size
, GFP_KERNEL
);
3159 if (!pdata
->ptrs
[i
])
3161 memset(pdata
->ptrs
[i
], 0, size
);
3164 /* Catch derefs w/o wrappers */
3165 return (void *)(~(unsigned long)pdata
);
3169 if (!cpu_possible(i
))
3171 kfree(pdata
->ptrs
[i
]);
3176 EXPORT_SYMBOL(__alloc_percpu
);
3180 * kmem_cache_free - Deallocate an object
3181 * @cachep: The cache the allocation was from.
3182 * @objp: The previously allocated object.
3184 * Free an object which was previously allocated from this
3187 void kmem_cache_free(struct kmem_cache
*cachep
, void *objp
)
3189 unsigned long flags
;
3191 local_irq_save(flags
);
3192 __cache_free(cachep
, objp
);
3193 local_irq_restore(flags
);
3195 EXPORT_SYMBOL(kmem_cache_free
);
3198 * kfree - free previously allocated memory
3199 * @objp: pointer returned by kmalloc.
3201 * If @objp is NULL, no operation is performed.
3203 * Don't free memory not originally allocated by kmalloc()
3204 * or you will run into trouble.
3206 void kfree(const void *objp
)
3208 struct kmem_cache
*c
;
3209 unsigned long flags
;
3211 if (unlikely(!objp
))
3213 local_irq_save(flags
);
3214 kfree_debugcheck(objp
);
3215 c
= virt_to_cache(objp
);
3216 mutex_debug_check_no_locks_freed(objp
, obj_size(c
));
3217 __cache_free(c
, (void *)objp
);
3218 local_irq_restore(flags
);
3220 EXPORT_SYMBOL(kfree
);
3224 * free_percpu - free previously allocated percpu memory
3225 * @objp: pointer returned by alloc_percpu.
3227 * Don't free memory not originally allocated by alloc_percpu()
3228 * The complemented objp is to check for that.
3230 void free_percpu(const void *objp
)
3233 struct percpu_data
*p
= (struct percpu_data
*)(~(unsigned long)objp
);
3236 * We allocate for all cpus so we cannot use for online cpu here.
3242 EXPORT_SYMBOL(free_percpu
);
3245 unsigned int kmem_cache_size(struct kmem_cache
*cachep
)
3247 return obj_size(cachep
);
3249 EXPORT_SYMBOL(kmem_cache_size
);
3251 const char *kmem_cache_name(struct kmem_cache
*cachep
)
3253 return cachep
->name
;
3255 EXPORT_SYMBOL_GPL(kmem_cache_name
);
3258 * This initializes kmem_list3 for all nodes.
3260 static int alloc_kmemlist(struct kmem_cache
*cachep
)
3263 struct kmem_list3
*l3
;
3266 for_each_online_node(node
) {
3267 struct array_cache
*nc
= NULL
, *new;
3268 struct array_cache
**new_alien
= NULL
;
3270 if (!(new_alien
= alloc_alien_cache(node
, cachep
->limit
)))
3273 if (!(new = alloc_arraycache(node
, (cachep
->shared
*
3274 cachep
->batchcount
),
3277 if ((l3
= cachep
->nodelists
[node
])) {
3279 spin_lock_irq(&l3
->list_lock
);
3281 if ((nc
= cachep
->nodelists
[node
]->shared
))
3282 free_block(cachep
, nc
->entry
, nc
->avail
, node
);
3285 if (!cachep
->nodelists
[node
]->alien
) {
3286 l3
->alien
= new_alien
;
3289 l3
->free_limit
= (1 + nr_cpus_node(node
)) *
3290 cachep
->batchcount
+ cachep
->num
;
3291 spin_unlock_irq(&l3
->list_lock
);
3293 free_alien_cache(new_alien
);
3296 if (!(l3
= kmalloc_node(sizeof(struct kmem_list3
),
3300 kmem_list3_init(l3
);
3301 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
+
3302 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
3304 l3
->alien
= new_alien
;
3305 l3
->free_limit
= (1 + nr_cpus_node(node
)) *
3306 cachep
->batchcount
+ cachep
->num
;
3307 cachep
->nodelists
[node
] = l3
;
3315 struct ccupdate_struct
{
3316 struct kmem_cache
*cachep
;
3317 struct array_cache
*new[NR_CPUS
];
3320 static void do_ccupdate_local(void *info
)
3322 struct ccupdate_struct
*new = (struct ccupdate_struct
*)info
;
3323 struct array_cache
*old
;
3326 old
= cpu_cache_get(new->cachep
);
3328 new->cachep
->array
[smp_processor_id()] = new->new[smp_processor_id()];
3329 new->new[smp_processor_id()] = old
;
3332 static int do_tune_cpucache(struct kmem_cache
*cachep
, int limit
, int batchcount
,
3335 struct ccupdate_struct
new;
3338 memset(&new.new, 0, sizeof(new.new));
3339 for_each_online_cpu(i
) {
3341 alloc_arraycache(cpu_to_node(i
), limit
, batchcount
);
3343 for (i
--; i
>= 0; i
--)
3348 new.cachep
= cachep
;
3350 smp_call_function_all_cpus(do_ccupdate_local
, (void *)&new);
3353 spin_lock(&cachep
->spinlock
);
3354 cachep
->batchcount
= batchcount
;
3355 cachep
->limit
= limit
;
3356 cachep
->shared
= shared
;
3357 spin_unlock(&cachep
->spinlock
);
3359 for_each_online_cpu(i
) {
3360 struct array_cache
*ccold
= new.new[i
];
3363 spin_lock_irq(&cachep
->nodelists
[cpu_to_node(i
)]->list_lock
);
3364 free_block(cachep
, ccold
->entry
, ccold
->avail
, cpu_to_node(i
));
3365 spin_unlock_irq(&cachep
->nodelists
[cpu_to_node(i
)]->list_lock
);
3369 err
= alloc_kmemlist(cachep
);
3371 printk(KERN_ERR
"alloc_kmemlist failed for %s, error %d.\n",
3372 cachep
->name
, -err
);
3378 static void enable_cpucache(struct kmem_cache
*cachep
)
3383 /* The head array serves three purposes:
3384 * - create a LIFO ordering, i.e. return objects that are cache-warm
3385 * - reduce the number of spinlock operations.
3386 * - reduce the number of linked list operations on the slab and
3387 * bufctl chains: array operations are cheaper.
3388 * The numbers are guessed, we should auto-tune as described by
3391 if (cachep
->buffer_size
> 131072)
3393 else if (cachep
->buffer_size
> PAGE_SIZE
)
3395 else if (cachep
->buffer_size
> 1024)
3397 else if (cachep
->buffer_size
> 256)
3402 /* Cpu bound tasks (e.g. network routing) can exhibit cpu bound
3403 * allocation behaviour: Most allocs on one cpu, most free operations
3404 * on another cpu. For these cases, an efficient object passing between
3405 * cpus is necessary. This is provided by a shared array. The array
3406 * replaces Bonwick's magazine layer.
3407 * On uniprocessor, it's functionally equivalent (but less efficient)
3408 * to a larger limit. Thus disabled by default.
3412 if (cachep
->buffer_size
<= PAGE_SIZE
)
3417 /* With debugging enabled, large batchcount lead to excessively
3418 * long periods with disabled local interrupts. Limit the
3424 err
= do_tune_cpucache(cachep
, limit
, (limit
+ 1) / 2, shared
);
3426 printk(KERN_ERR
"enable_cpucache failed for %s, error %d.\n",
3427 cachep
->name
, -err
);
3430 static void drain_array_locked(struct kmem_cache
*cachep
, struct array_cache
*ac
,
3431 int force
, int node
)
3435 check_spinlock_acquired_node(cachep
, node
);
3436 if (ac
->touched
&& !force
) {
3438 } else if (ac
->avail
) {
3439 tofree
= force
? ac
->avail
: (ac
->limit
+ 4) / 5;
3440 if (tofree
> ac
->avail
) {
3441 tofree
= (ac
->avail
+ 1) / 2;
3443 free_block(cachep
, ac
->entry
, tofree
, node
);
3444 ac
->avail
-= tofree
;
3445 memmove(ac
->entry
, &(ac
->entry
[tofree
]),
3446 sizeof(void *) * ac
->avail
);
3451 * cache_reap - Reclaim memory from caches.
3452 * @unused: unused parameter
3454 * Called from workqueue/eventd every few seconds.
3456 * - clear the per-cpu caches for this CPU.
3457 * - return freeable pages to the main free memory pool.
3459 * If we cannot acquire the cache chain mutex then just give up - we'll
3460 * try again on the next iteration.
3462 static void cache_reap(void *unused
)
3464 struct list_head
*walk
;
3465 struct kmem_list3
*l3
;
3467 if (!mutex_trylock(&cache_chain_mutex
)) {
3468 /* Give up. Setup the next iteration. */
3469 schedule_delayed_work(&__get_cpu_var(reap_work
),
3474 list_for_each(walk
, &cache_chain
) {
3475 struct kmem_cache
*searchp
;
3476 struct list_head
*p
;
3480 searchp
= list_entry(walk
, struct kmem_cache
, next
);
3482 if (searchp
->flags
& SLAB_NO_REAP
)
3487 l3
= searchp
->nodelists
[numa_node_id()];
3489 drain_alien_cache(searchp
, l3
->alien
);
3490 spin_lock_irq(&l3
->list_lock
);
3492 drain_array_locked(searchp
, cpu_cache_get(searchp
), 0,
3495 if (time_after(l3
->next_reap
, jiffies
))
3498 l3
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
;
3501 drain_array_locked(searchp
, l3
->shared
, 0,
3504 if (l3
->free_touched
) {
3505 l3
->free_touched
= 0;
3510 (l3
->free_limit
+ 5 * searchp
->num
-
3511 1) / (5 * searchp
->num
);
3513 p
= l3
->slabs_free
.next
;
3514 if (p
== &(l3
->slabs_free
))
3517 slabp
= list_entry(p
, struct slab
, list
);
3518 BUG_ON(slabp
->inuse
);
3519 list_del(&slabp
->list
);
3520 STATS_INC_REAPED(searchp
);
3522 /* Safe to drop the lock. The slab is no longer
3523 * linked to the cache.
3524 * searchp cannot disappear, we hold
3527 l3
->free_objects
-= searchp
->num
;
3528 spin_unlock_irq(&l3
->list_lock
);
3529 slab_destroy(searchp
, slabp
);
3530 spin_lock_irq(&l3
->list_lock
);
3531 } while (--tofree
> 0);
3533 spin_unlock_irq(&l3
->list_lock
);
3538 mutex_unlock(&cache_chain_mutex
);
3539 drain_remote_pages();
3540 /* Setup the next iteration */
3541 schedule_delayed_work(&__get_cpu_var(reap_work
), REAPTIMEOUT_CPUC
);
3544 #ifdef CONFIG_PROC_FS
3546 static void print_slabinfo_header(struct seq_file
*m
)
3549 * Output format version, so at least we can change it
3550 * without _too_ many complaints.
3553 seq_puts(m
, "slabinfo - version: 2.1 (statistics)\n");
3555 seq_puts(m
, "slabinfo - version: 2.1\n");
3557 seq_puts(m
, "# name <active_objs> <num_objs> <objsize> "
3558 "<objperslab> <pagesperslab>");
3559 seq_puts(m
, " : tunables <limit> <batchcount> <sharedfactor>");
3560 seq_puts(m
, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
3562 seq_puts(m
, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
3563 "<error> <maxfreeable> <nodeallocs> <remotefrees>");
3564 seq_puts(m
, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
3569 static void *s_start(struct seq_file
*m
, loff_t
*pos
)
3572 struct list_head
*p
;
3574 mutex_lock(&cache_chain_mutex
);
3576 print_slabinfo_header(m
);
3577 p
= cache_chain
.next
;
3580 if (p
== &cache_chain
)
3583 return list_entry(p
, struct kmem_cache
, next
);
3586 static void *s_next(struct seq_file
*m
, void *p
, loff_t
*pos
)
3588 struct kmem_cache
*cachep
= p
;
3590 return cachep
->next
.next
== &cache_chain
? NULL
3591 : list_entry(cachep
->next
.next
, struct kmem_cache
, next
);
3594 static void s_stop(struct seq_file
*m
, void *p
)
3596 mutex_unlock(&cache_chain_mutex
);
3599 static int s_show(struct seq_file
*m
, void *p
)
3601 struct kmem_cache
*cachep
= p
;
3602 struct list_head
*q
;
3604 unsigned long active_objs
;
3605 unsigned long num_objs
;
3606 unsigned long active_slabs
= 0;
3607 unsigned long num_slabs
, free_objects
= 0, shared_avail
= 0;
3611 struct kmem_list3
*l3
;
3613 spin_lock(&cachep
->spinlock
);
3616 for_each_online_node(node
) {
3617 l3
= cachep
->nodelists
[node
];
3622 spin_lock_irq(&l3
->list_lock
);
3624 list_for_each(q
, &l3
->slabs_full
) {
3625 slabp
= list_entry(q
, struct slab
, list
);
3626 if (slabp
->inuse
!= cachep
->num
&& !error
)
3627 error
= "slabs_full accounting error";
3628 active_objs
+= cachep
->num
;
3631 list_for_each(q
, &l3
->slabs_partial
) {
3632 slabp
= list_entry(q
, struct slab
, list
);
3633 if (slabp
->inuse
== cachep
->num
&& !error
)
3634 error
= "slabs_partial inuse accounting error";
3635 if (!slabp
->inuse
&& !error
)
3636 error
= "slabs_partial/inuse accounting error";
3637 active_objs
+= slabp
->inuse
;
3640 list_for_each(q
, &l3
->slabs_free
) {
3641 slabp
= list_entry(q
, struct slab
, list
);
3642 if (slabp
->inuse
&& !error
)
3643 error
= "slabs_free/inuse accounting error";
3646 free_objects
+= l3
->free_objects
;
3648 shared_avail
+= l3
->shared
->avail
;
3650 spin_unlock_irq(&l3
->list_lock
);
3652 num_slabs
+= active_slabs
;
3653 num_objs
= num_slabs
* cachep
->num
;
3654 if (num_objs
- active_objs
!= free_objects
&& !error
)
3655 error
= "free_objects accounting error";
3657 name
= cachep
->name
;
3659 printk(KERN_ERR
"slab: cache %s error: %s\n", name
, error
);
3661 seq_printf(m
, "%-17s %6lu %6lu %6u %4u %4d",
3662 name
, active_objs
, num_objs
, cachep
->buffer_size
,
3663 cachep
->num
, (1 << cachep
->gfporder
));
3664 seq_printf(m
, " : tunables %4u %4u %4u",
3665 cachep
->limit
, cachep
->batchcount
, cachep
->shared
);
3666 seq_printf(m
, " : slabdata %6lu %6lu %6lu",
3667 active_slabs
, num_slabs
, shared_avail
);
3670 unsigned long high
= cachep
->high_mark
;
3671 unsigned long allocs
= cachep
->num_allocations
;
3672 unsigned long grown
= cachep
->grown
;
3673 unsigned long reaped
= cachep
->reaped
;
3674 unsigned long errors
= cachep
->errors
;
3675 unsigned long max_freeable
= cachep
->max_freeable
;
3676 unsigned long node_allocs
= cachep
->node_allocs
;
3677 unsigned long node_frees
= cachep
->node_frees
;
3679 seq_printf(m
, " : globalstat %7lu %6lu %5lu %4lu \
3680 %4lu %4lu %4lu %4lu", allocs
, high
, grown
, reaped
, errors
, max_freeable
, node_allocs
, node_frees
);
3684 unsigned long allochit
= atomic_read(&cachep
->allochit
);
3685 unsigned long allocmiss
= atomic_read(&cachep
->allocmiss
);
3686 unsigned long freehit
= atomic_read(&cachep
->freehit
);
3687 unsigned long freemiss
= atomic_read(&cachep
->freemiss
);
3689 seq_printf(m
, " : cpustat %6lu %6lu %6lu %6lu",
3690 allochit
, allocmiss
, freehit
, freemiss
);
3694 spin_unlock(&cachep
->spinlock
);
3699 * slabinfo_op - iterator that generates /proc/slabinfo
3708 * num-pages-per-slab
3709 * + further values on SMP and with statistics enabled
3712 struct seq_operations slabinfo_op
= {
3719 #define MAX_SLABINFO_WRITE 128
3721 * slabinfo_write - Tuning for the slab allocator
3723 * @buffer: user buffer
3724 * @count: data length
3727 ssize_t
slabinfo_write(struct file
*file
, const char __user
* buffer
,
3728 size_t count
, loff_t
*ppos
)
3730 char kbuf
[MAX_SLABINFO_WRITE
+ 1], *tmp
;
3731 int limit
, batchcount
, shared
, res
;
3732 struct list_head
*p
;
3734 if (count
> MAX_SLABINFO_WRITE
)
3736 if (copy_from_user(&kbuf
, buffer
, count
))
3738 kbuf
[MAX_SLABINFO_WRITE
] = '\0';
3740 tmp
= strchr(kbuf
, ' ');
3745 if (sscanf(tmp
, " %d %d %d", &limit
, &batchcount
, &shared
) != 3)
3748 /* Find the cache in the chain of caches. */
3749 mutex_lock(&cache_chain_mutex
);
3751 list_for_each(p
, &cache_chain
) {
3752 struct kmem_cache
*cachep
= list_entry(p
, struct kmem_cache
,
3755 if (!strcmp(cachep
->name
, kbuf
)) {
3758 batchcount
> limit
|| shared
< 0) {
3761 res
= do_tune_cpucache(cachep
, limit
,
3762 batchcount
, shared
);
3767 mutex_unlock(&cache_chain_mutex
);
3775 * ksize - get the actual amount of memory allocated for a given object
3776 * @objp: Pointer to the object
3778 * kmalloc may internally round up allocations and return more memory
3779 * than requested. ksize() can be used to determine the actual amount of
3780 * memory allocated. The caller may use this additional memory, even though
3781 * a smaller amount of memory was initially specified with the kmalloc call.
3782 * The caller must guarantee that objp points to a valid object previously
3783 * allocated with either kmalloc() or kmem_cache_alloc(). The object
3784 * must not be freed during the duration of the call.
3786 unsigned int ksize(const void *objp
)
3788 if (unlikely(objp
== NULL
))
3791 return obj_size(virt_to_cache(objp
));