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/cpuset.h>
98 #include <linux/seq_file.h>
99 #include <linux/notifier.h>
100 #include <linux/kallsyms.h>
101 #include <linux/cpu.h>
102 #include <linux/sysctl.h>
103 #include <linux/module.h>
104 #include <linux/rcupdate.h>
105 #include <linux/string.h>
106 #include <linux/nodemask.h>
107 #include <linux/mempolicy.h>
108 #include <linux/mutex.h>
110 #include <asm/uaccess.h>
111 #include <asm/cacheflush.h>
112 #include <asm/tlbflush.h>
113 #include <asm/page.h>
116 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
117 * SLAB_RED_ZONE & SLAB_POISON.
118 * 0 for faster, smaller code (especially in the critical paths).
120 * STATS - 1 to collect stats for /proc/slabinfo.
121 * 0 for faster, smaller code (especially in the critical paths).
123 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
126 #ifdef CONFIG_DEBUG_SLAB
129 #define FORCED_DEBUG 1
133 #define FORCED_DEBUG 0
136 /* Shouldn't this be in a header file somewhere? */
137 #define BYTES_PER_WORD sizeof(void *)
139 #ifndef cache_line_size
140 #define cache_line_size() L1_CACHE_BYTES
143 #ifndef ARCH_KMALLOC_MINALIGN
145 * Enforce a minimum alignment for the kmalloc caches.
146 * Usually, the kmalloc caches are cache_line_size() aligned, except when
147 * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
148 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
149 * alignment larger than BYTES_PER_WORD. ARCH_KMALLOC_MINALIGN allows that.
150 * Note that this flag disables some debug features.
152 #define ARCH_KMALLOC_MINALIGN 0
155 #ifndef ARCH_SLAB_MINALIGN
157 * Enforce a minimum alignment for all caches.
158 * Intended for archs that get misalignment faults even for BYTES_PER_WORD
159 * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
160 * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
161 * some debug features.
163 #define ARCH_SLAB_MINALIGN 0
166 #ifndef ARCH_KMALLOC_FLAGS
167 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
170 /* Legal flag mask for kmem_cache_create(). */
172 # define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
173 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
175 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \
176 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
177 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD)
179 # define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
180 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \
181 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
182 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD)
188 * Bufctl's are used for linking objs within a slab
191 * This implementation relies on "struct page" for locating the cache &
192 * slab an object belongs to.
193 * This allows the bufctl structure to be small (one int), but limits
194 * the number of objects a slab (not a cache) can contain when off-slab
195 * bufctls are used. The limit is the size of the largest general cache
196 * that does not use off-slab slabs.
197 * For 32bit archs with 4 kB pages, is this 56.
198 * This is not serious, as it is only for large objects, when it is unwise
199 * to have too many per slab.
200 * Note: This limit can be raised by introducing a general cache whose size
201 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
204 typedef unsigned int kmem_bufctl_t;
205 #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
206 #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
207 #define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2)
208 #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3)
213 * Manages the objs in a slab. Placed either at the beginning of mem allocated
214 * for a slab, or allocated from an general cache.
215 * Slabs are chained into three list: fully used, partial, fully free slabs.
218 struct list_head list;
219 unsigned long colouroff;
220 void *s_mem; /* including colour offset */
221 unsigned int inuse; /* num of objs active in slab */
223 unsigned short nodeid;
229 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
230 * arrange for kmem_freepages to be called via RCU. This is useful if
231 * we need to approach a kernel structure obliquely, from its address
232 * obtained without the usual locking. We can lock the structure to
233 * stabilize it and check it's still at the given address, only if we
234 * can be sure that the memory has not been meanwhile reused for some
235 * other kind of object (which our subsystem's lock might corrupt).
237 * rcu_read_lock before reading the address, then rcu_read_unlock after
238 * taking the spinlock within the structure expected at that address.
240 * We assume struct slab_rcu can overlay struct slab when destroying.
243 struct rcu_head head;
244 struct kmem_cache *cachep;
252 * - LIFO ordering, to hand out cache-warm objects from _alloc
253 * - reduce the number of linked list operations
254 * - reduce spinlock operations
256 * The limit is stored in the per-cpu structure to reduce the data cache
263 unsigned int batchcount;
264 unsigned int touched;
267 * Must have this definition in here for the proper
268 * alignment of array_cache. Also simplifies accessing
270 * [0] is for gcc 2.95. It should really be [].
275 * bootstrap: The caches do not work without cpuarrays anymore, but the
276 * cpuarrays are allocated from the generic caches...
278 #define BOOT_CPUCACHE_ENTRIES 1
279 struct arraycache_init {
280 struct array_cache cache;
281 void *entries[BOOT_CPUCACHE_ENTRIES];
285 * The slab lists for all objects.
288 struct list_head slabs_partial; /* partial list first, better asm code */
289 struct list_head slabs_full;
290 struct list_head slabs_free;
291 unsigned long free_objects;
292 unsigned int free_limit;
293 unsigned int colour_next; /* Per-node cache coloring */
294 spinlock_t list_lock;
295 struct array_cache *shared; /* shared per node */
296 struct array_cache **alien; /* on other nodes */
297 unsigned long next_reap; /* updated without locking */
298 int free_touched; /* updated without locking */
302 * Need this for bootstrapping a per node allocator.
304 #define NUM_INIT_LISTS (2 * MAX_NUMNODES + 1)
305 struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
306 #define CACHE_CACHE 0
308 #define SIZE_L3 (1 + MAX_NUMNODES)
311 * This function must be completely optimized away if a constant is passed to
312 * it. Mostly the same as what is in linux/slab.h except it returns an index.
314 static __always_inline int index_of(const size_t size)
316 extern void __bad_size(void);
318 if (__builtin_constant_p(size)) {
326 #include "linux/kmalloc_sizes.h"
334 #define INDEX_AC index_of(sizeof(struct arraycache_init))
335 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
337 static void kmem_list3_init(struct kmem_list3 *parent)
339 INIT_LIST_HEAD(&parent->slabs_full);
340 INIT_LIST_HEAD(&parent->slabs_partial);
341 INIT_LIST_HEAD(&parent->slabs_free);
342 parent->shared = NULL;
343 parent->alien = NULL;
344 parent->colour_next = 0;
345 spin_lock_init(&parent->list_lock);
346 parent->free_objects = 0;
347 parent->free_touched = 0;
350 #define MAKE_LIST(cachep, listp, slab, nodeid) \
352 INIT_LIST_HEAD(listp); \
353 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
356 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
358 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
359 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
360 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
370 /* 1) per-cpu data, touched during every alloc/free */
371 struct array_cache *array[NR_CPUS];
372 /* 2) Cache tunables. Protected by cache_chain_mutex */
373 unsigned int batchcount;
377 unsigned int buffer_size;
378 /* 3) touched by every alloc & free from the backend */
379 struct kmem_list3 *nodelists[MAX_NUMNODES];
381 unsigned int flags; /* constant flags */
382 unsigned int num; /* # of objs per slab */
384 /* 4) cache_grow/shrink */
385 /* order of pgs per slab (2^n) */
386 unsigned int gfporder;
388 /* force GFP flags, e.g. GFP_DMA */
391 size_t colour; /* cache colouring range */
392 unsigned int colour_off; /* colour offset */
393 struct kmem_cache *slabp_cache;
394 unsigned int slab_size;
395 unsigned int dflags; /* dynamic flags */
397 /* constructor func */
398 void (*ctor) (void *, struct kmem_cache *, unsigned long);
400 /* de-constructor func */
401 void (*dtor) (void *, struct kmem_cache *, unsigned long);
403 /* 5) cache creation/removal */
405 struct list_head next;
409 unsigned long num_active;
410 unsigned long num_allocations;
411 unsigned long high_mark;
413 unsigned long reaped;
414 unsigned long errors;
415 unsigned long max_freeable;
416 unsigned long node_allocs;
417 unsigned long node_frees;
418 unsigned long node_overflow;
426 * If debugging is enabled, then the allocator can add additional
427 * fields and/or padding to every object. buffer_size contains the total
428 * object size including these internal fields, the following two
429 * variables contain the offset to the user object and its size.
436 #define CFLGS_OFF_SLAB (0x80000000UL)
437 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
439 #define BATCHREFILL_LIMIT 16
441 * Optimization question: fewer reaps means less probability for unnessary
442 * 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) \
458 if ((x)->num_active > (x)->high_mark) \
459 (x)->high_mark = (x)->num_active; \
461 #define STATS_INC_ERR(x) ((x)->errors++)
462 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
463 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
464 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
465 #define STATS_SET_FREEABLE(x, i) \
467 if ((x)->max_freeable < i) \
468 (x)->max_freeable = i; \
470 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
471 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
472 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
473 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
475 #define STATS_INC_ACTIVE(x) do { } while (0)
476 #define STATS_DEC_ACTIVE(x) do { } while (0)
477 #define STATS_INC_ALLOCED(x) do { } while (0)
478 #define STATS_INC_GROWN(x) do { } while (0)
479 #define STATS_INC_REAPED(x) do { } while (0)
480 #define STATS_SET_HIGH(x) do { } while (0)
481 #define STATS_INC_ERR(x) do { } while (0)
482 #define STATS_INC_NODEALLOCS(x) do { } while (0)
483 #define STATS_INC_NODEFREES(x) do { } while (0)
484 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
485 #define STATS_SET_FREEABLE(x, i) do { } while (0)
486 #define STATS_INC_ALLOCHIT(x) do { } while (0)
487 #define STATS_INC_ALLOCMISS(x) do { } while (0)
488 #define STATS_INC_FREEHIT(x) do { } while (0)
489 #define STATS_INC_FREEMISS(x) do { } while (0)
494 * Magic nums for obj red zoning.
495 * Placed in the first word before and the first word after an obj.
497 #define RED_INACTIVE 0x5A2CF071UL /* when obj is inactive */
498 #define RED_ACTIVE 0x170FC2A5UL /* when obj is active */
500 /* ...and for poisoning */
501 #define POISON_INUSE 0x5a /* for use-uninitialised poisoning */
502 #define POISON_FREE 0x6b /* for use-after-free poisoning */
503 #define POISON_END 0xa5 /* end-byte of poisoning */
506 * memory layout of objects:
508 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
509 * the end of an object is aligned with the end of the real
510 * allocation. Catches writes behind the end of the allocation.
511 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
513 * cachep->obj_offset: The real object.
514 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
515 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
516 * [BYTES_PER_WORD long]
518 static int obj_offset(struct kmem_cache *cachep)
520 return cachep->obj_offset;
523 static int obj_size(struct kmem_cache *cachep)
525 return cachep->obj_size;
528 static unsigned long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
530 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
531 return (unsigned long*) (objp+obj_offset(cachep)-BYTES_PER_WORD);
534 static unsigned long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
536 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
537 if (cachep->flags & SLAB_STORE_USER)
538 return (unsigned long *)(objp + cachep->buffer_size -
540 return (unsigned long *)(objp + cachep->buffer_size - BYTES_PER_WORD);
543 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
545 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
546 return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
551 #define obj_offset(x) 0
552 #define obj_size(cachep) (cachep->buffer_size)
553 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long *)NULL;})
554 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long *)NULL;})
555 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
560 * Maximum size of an obj (in 2^order pages) and absolute limit for the gfp
563 #if defined(CONFIG_LARGE_ALLOCS)
564 #define MAX_OBJ_ORDER 13 /* up to 32Mb */
565 #define MAX_GFP_ORDER 13 /* up to 32Mb */
566 #elif defined(CONFIG_MMU)
567 #define MAX_OBJ_ORDER 5 /* 32 pages */
568 #define MAX_GFP_ORDER 5 /* 32 pages */
570 #define MAX_OBJ_ORDER 8 /* up to 1Mb */
571 #define MAX_GFP_ORDER 8 /* up to 1Mb */
575 * Do not go above this order unless 0 objects fit into the slab.
577 #define BREAK_GFP_ORDER_HI 1
578 #define BREAK_GFP_ORDER_LO 0
579 static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
582 * Functions for storing/retrieving the cachep and or slab from the page
583 * allocator. These are used to find the slab an obj belongs to. With kfree(),
584 * these are used to find the cache which an obj belongs to.
586 static inline void page_set_cache(struct page *page, struct kmem_cache *cache)
588 page->lru.next = (struct list_head *)cache;
591 static inline struct kmem_cache *page_get_cache(struct page *page)
593 if (unlikely(PageCompound(page)))
594 page = (struct page *)page_private(page);
595 return (struct kmem_cache *)page->lru.next;
598 static inline void page_set_slab(struct page *page, struct slab *slab)
600 page->lru.prev = (struct list_head *)slab;
603 static inline struct slab *page_get_slab(struct page *page)
605 if (unlikely(PageCompound(page)))
606 page = (struct page *)page_private(page);
607 return (struct slab *)page->lru.prev;
610 static inline struct kmem_cache *virt_to_cache(const void *obj)
612 struct page *page = virt_to_page(obj);
613 return page_get_cache(page);
616 static inline struct slab *virt_to_slab(const void *obj)
618 struct page *page = virt_to_page(obj);
619 return page_get_slab(page);
622 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
625 return slab->s_mem + cache->buffer_size * idx;
628 static inline unsigned int obj_to_index(struct kmem_cache *cache,
629 struct slab *slab, void *obj)
631 return (unsigned)(obj - slab->s_mem) / cache->buffer_size;
635 * These are the default caches for kmalloc. Custom caches can have other sizes.
637 struct cache_sizes malloc_sizes[] = {
638 #define CACHE(x) { .cs_size = (x) },
639 #include <linux/kmalloc_sizes.h>
643 EXPORT_SYMBOL(malloc_sizes);
645 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
651 static struct cache_names __initdata cache_names[] = {
652 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
653 #include <linux/kmalloc_sizes.h>
658 static struct arraycache_init initarray_cache __initdata =
659 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
660 static struct arraycache_init initarray_generic =
661 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
663 /* internal cache of cache description objs */
664 static struct kmem_cache cache_cache = {
666 .limit = BOOT_CPUCACHE_ENTRIES,
668 .buffer_size = sizeof(struct kmem_cache),
669 .name = "kmem_cache",
671 .obj_size = sizeof(struct kmem_cache),
675 /* Guard access to the cache-chain. */
676 static DEFINE_MUTEX(cache_chain_mutex);
677 static struct list_head cache_chain;
680 * vm_enough_memory() looks at this to determine how many slab-allocated pages
681 * are possibly freeable under pressure
683 * SLAB_RECLAIM_ACCOUNT turns this on per-slab
685 atomic_t slab_reclaim_pages;
688 * chicken and egg problem: delay the per-cpu array allocation
689 * until the general caches are up.
699 * used by boot code to determine if it can use slab based allocator
701 int slab_is_available(void)
703 return g_cpucache_up == FULL;
706 static DEFINE_PER_CPU(struct work_struct, reap_work);
708 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
710 static void enable_cpucache(struct kmem_cache *cachep);
711 static void cache_reap(void *unused);
712 static int __node_shrink(struct kmem_cache *cachep, int node);
714 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
716 return cachep->array[smp_processor_id()];
719 static inline struct kmem_cache *__find_general_cachep(size_t size,
722 struct cache_sizes *csizep = malloc_sizes;
725 /* This happens if someone tries to call
726 * kmem_cache_create(), or __kmalloc(), before
727 * the generic caches are initialized.
729 BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
731 while (size > csizep->cs_size)
735 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
736 * has cs_{dma,}cachep==NULL. Thus no special case
737 * for large kmalloc calls required.
739 if (unlikely(gfpflags & GFP_DMA))
740 return csizep->cs_dmacachep;
741 return csizep->cs_cachep;
744 struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
746 return __find_general_cachep(size, gfpflags);
748 EXPORT_SYMBOL(kmem_find_general_cachep);
750 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
752 return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
756 * Calculate the number of objects and left-over bytes for a given buffer size.
758 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
759 size_t align, int flags, size_t *left_over,
764 size_t slab_size = PAGE_SIZE << gfporder;
767 * The slab management structure can be either off the slab or
768 * on it. For the latter case, the memory allocated for a
772 * - One kmem_bufctl_t for each object
773 * - Padding to respect alignment of @align
774 * - @buffer_size bytes for each object
776 * If the slab management structure is off the slab, then the
777 * alignment will already be calculated into the size. Because
778 * the slabs are all pages aligned, the objects will be at the
779 * correct alignment when allocated.
781 if (flags & CFLGS_OFF_SLAB) {
783 nr_objs = slab_size / buffer_size;
785 if (nr_objs > SLAB_LIMIT)
786 nr_objs = SLAB_LIMIT;
789 * Ignore padding for the initial guess. The padding
790 * is at most @align-1 bytes, and @buffer_size is at
791 * least @align. In the worst case, this result will
792 * be one greater than the number of objects that fit
793 * into the memory allocation when taking the padding
796 nr_objs = (slab_size - sizeof(struct slab)) /
797 (buffer_size + sizeof(kmem_bufctl_t));
800 * This calculated number will be either the right
801 * amount, or one greater than what we want.
803 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
807 if (nr_objs > SLAB_LIMIT)
808 nr_objs = SLAB_LIMIT;
810 mgmt_size = slab_mgmt_size(nr_objs, align);
813 *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
816 #define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg)
818 static void __slab_error(const char *function, struct kmem_cache *cachep,
821 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
822 function, cachep->name, msg);
828 * Special reaping functions for NUMA systems called from cache_reap().
829 * These take care of doing round robin flushing of alien caches (containing
830 * objects freed on different nodes from which they were allocated) and the
831 * flushing of remote pcps by calling drain_node_pages.
833 static DEFINE_PER_CPU(unsigned long, reap_node);
835 static void init_reap_node(int cpu)
839 node = next_node(cpu_to_node(cpu), node_online_map);
840 if (node == MAX_NUMNODES)
841 node = first_node(node_online_map);
843 __get_cpu_var(reap_node) = node;
846 static void next_reap_node(void)
848 int node = __get_cpu_var(reap_node);
851 * Also drain per cpu pages on remote zones
853 if (node != numa_node_id())
854 drain_node_pages(node);
856 node = next_node(node, node_online_map);
857 if (unlikely(node >= MAX_NUMNODES))
858 node = first_node(node_online_map);
859 __get_cpu_var(reap_node) = node;
863 #define init_reap_node(cpu) do { } while (0)
864 #define next_reap_node(void) do { } while (0)
868 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
869 * via the workqueue/eventd.
870 * Add the CPU number into the expiration time to minimize the possibility of
871 * the CPUs getting into lockstep and contending for the global cache chain
874 static void __devinit start_cpu_timer(int cpu)
876 struct work_struct *reap_work = &per_cpu(reap_work, cpu);
879 * When this gets called from do_initcalls via cpucache_init(),
880 * init_workqueues() has already run, so keventd will be setup
883 if (keventd_up() && reap_work->func == NULL) {
885 INIT_WORK(reap_work, cache_reap, NULL);
886 schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu);
890 static struct array_cache *alloc_arraycache(int node, int entries,
893 int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
894 struct array_cache *nc = NULL;
896 nc = kmalloc_node(memsize, GFP_KERNEL, node);
900 nc->batchcount = batchcount;
902 spin_lock_init(&nc->lock);
908 * Transfer objects in one arraycache to another.
909 * Locking must be handled by the caller.
911 * Return the number of entries transferred.
913 static int transfer_objects(struct array_cache *to,
914 struct array_cache *from, unsigned int max)
916 /* Figure out how many entries to transfer */
917 int nr = min(min(from->avail, max), to->limit - to->avail);
922 memcpy(to->entry + to->avail, from->entry + from->avail -nr,
932 static void *__cache_alloc_node(struct kmem_cache *, gfp_t, int);
933 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
935 static struct array_cache **alloc_alien_cache(int node, int limit)
937 struct array_cache **ac_ptr;
938 int memsize = sizeof(void *) * MAX_NUMNODES;
943 ac_ptr = kmalloc_node(memsize, GFP_KERNEL, node);
946 if (i == node || !node_online(i)) {
950 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d);
952 for (i--; i <= 0; i--)
962 static void free_alien_cache(struct array_cache **ac_ptr)
973 static void __drain_alien_cache(struct kmem_cache *cachep,
974 struct array_cache *ac, int node)
976 struct kmem_list3 *rl3 = cachep->nodelists[node];
979 spin_lock(&rl3->list_lock);
981 * Stuff objects into the remote nodes shared array first.
982 * That way we could avoid the overhead of putting the objects
983 * into the free lists and getting them back later.
986 transfer_objects(rl3->shared, ac, ac->limit);
988 free_block(cachep, ac->entry, ac->avail, node);
990 spin_unlock(&rl3->list_lock);
995 * Called from cache_reap() to regularly drain alien caches round robin.
997 static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
999 int node = __get_cpu_var(reap_node);
1002 struct array_cache *ac = l3->alien[node];
1004 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1005 __drain_alien_cache(cachep, ac, node);
1006 spin_unlock_irq(&ac->lock);
1011 static void drain_alien_cache(struct kmem_cache *cachep,
1012 struct array_cache **alien)
1015 struct array_cache *ac;
1016 unsigned long flags;
1018 for_each_online_node(i) {
1021 spin_lock_irqsave(&ac->lock, flags);
1022 __drain_alien_cache(cachep, ac, i);
1023 spin_unlock_irqrestore(&ac->lock, flags);
1028 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1030 struct slab *slabp = virt_to_slab(objp);
1031 int nodeid = slabp->nodeid;
1032 struct kmem_list3 *l3;
1033 struct array_cache *alien = NULL;
1036 * Make sure we are not freeing a object from another node to the array
1037 * cache on this cpu.
1039 if (likely(slabp->nodeid == numa_node_id()))
1042 l3 = cachep->nodelists[numa_node_id()];
1043 STATS_INC_NODEFREES(cachep);
1044 if (l3->alien && l3->alien[nodeid]) {
1045 alien = l3->alien[nodeid];
1046 spin_lock(&alien->lock);
1047 if (unlikely(alien->avail == alien->limit)) {
1048 STATS_INC_ACOVERFLOW(cachep);
1049 __drain_alien_cache(cachep, alien, nodeid);
1051 alien->entry[alien->avail++] = objp;
1052 spin_unlock(&alien->lock);
1054 spin_lock(&(cachep->nodelists[nodeid])->list_lock);
1055 free_block(cachep, &objp, 1, nodeid);
1056 spin_unlock(&(cachep->nodelists[nodeid])->list_lock);
1063 #define drain_alien_cache(cachep, alien) do { } while (0)
1064 #define reap_alien(cachep, l3) do { } while (0)
1066 static inline struct array_cache **alloc_alien_cache(int node, int limit)
1068 return (struct array_cache **) 0x01020304ul;
1071 static inline void free_alien_cache(struct array_cache **ac_ptr)
1075 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1082 static int cpuup_callback(struct notifier_block *nfb,
1083 unsigned long action, void *hcpu)
1085 long cpu = (long)hcpu;
1086 struct kmem_cache *cachep;
1087 struct kmem_list3 *l3 = NULL;
1088 int node = cpu_to_node(cpu);
1089 int memsize = sizeof(struct kmem_list3);
1092 case CPU_UP_PREPARE:
1093 mutex_lock(&cache_chain_mutex);
1095 * We need to do this right in the beginning since
1096 * alloc_arraycache's are going to use this list.
1097 * kmalloc_node allows us to add the slab to the right
1098 * kmem_list3 and not this cpu's kmem_list3
1101 list_for_each_entry(cachep, &cache_chain, next) {
1103 * Set up the size64 kmemlist for cpu before we can
1104 * begin anything. Make sure some other cpu on this
1105 * node has not already allocated this
1107 if (!cachep->nodelists[node]) {
1108 l3 = kmalloc_node(memsize, GFP_KERNEL, node);
1111 kmem_list3_init(l3);
1112 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1113 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1116 * The l3s don't come and go as CPUs come and
1117 * go. cache_chain_mutex is sufficient
1120 cachep->nodelists[node] = l3;
1123 spin_lock_irq(&cachep->nodelists[node]->list_lock);
1124 cachep->nodelists[node]->free_limit =
1125 (1 + nr_cpus_node(node)) *
1126 cachep->batchcount + cachep->num;
1127 spin_unlock_irq(&cachep->nodelists[node]->list_lock);
1131 * Now we can go ahead with allocating the shared arrays and
1134 list_for_each_entry(cachep, &cache_chain, next) {
1135 struct array_cache *nc;
1136 struct array_cache *shared;
1137 struct array_cache **alien;
1139 nc = alloc_arraycache(node, cachep->limit,
1140 cachep->batchcount);
1143 shared = alloc_arraycache(node,
1144 cachep->shared * cachep->batchcount,
1149 alien = alloc_alien_cache(node, cachep->limit);
1152 cachep->array[cpu] = nc;
1153 l3 = cachep->nodelists[node];
1156 spin_lock_irq(&l3->list_lock);
1159 * We are serialised from CPU_DEAD or
1160 * CPU_UP_CANCELLED by the cpucontrol lock
1162 l3->shared = shared;
1171 spin_unlock_irq(&l3->list_lock);
1173 free_alien_cache(alien);
1175 mutex_unlock(&cache_chain_mutex);
1178 start_cpu_timer(cpu);
1180 #ifdef CONFIG_HOTPLUG_CPU
1183 * Even if all the cpus of a node are down, we don't free the
1184 * kmem_list3 of any cache. This to avoid a race between
1185 * cpu_down, and a kmalloc allocation from another cpu for
1186 * memory from the node of the cpu going down. The list3
1187 * structure is usually allocated from kmem_cache_create() and
1188 * gets destroyed at kmem_cache_destroy().
1191 case CPU_UP_CANCELED:
1192 mutex_lock(&cache_chain_mutex);
1193 list_for_each_entry(cachep, &cache_chain, next) {
1194 struct array_cache *nc;
1195 struct array_cache *shared;
1196 struct array_cache **alien;
1199 mask = node_to_cpumask(node);
1200 /* cpu is dead; no one can alloc from it. */
1201 nc = cachep->array[cpu];
1202 cachep->array[cpu] = NULL;
1203 l3 = cachep->nodelists[node];
1206 goto free_array_cache;
1208 spin_lock_irq(&l3->list_lock);
1210 /* Free limit for this kmem_list3 */
1211 l3->free_limit -= cachep->batchcount;
1213 free_block(cachep, nc->entry, nc->avail, node);
1215 if (!cpus_empty(mask)) {
1216 spin_unlock_irq(&l3->list_lock);
1217 goto free_array_cache;
1220 shared = l3->shared;
1222 free_block(cachep, l3->shared->entry,
1223 l3->shared->avail, node);
1230 spin_unlock_irq(&l3->list_lock);
1234 drain_alien_cache(cachep, alien);
1235 free_alien_cache(alien);
1241 * In the previous loop, all the objects were freed to
1242 * the respective cache's slabs, now we can go ahead and
1243 * shrink each nodelist to its limit.
1245 list_for_each_entry(cachep, &cache_chain, next) {
1246 l3 = cachep->nodelists[node];
1249 spin_lock_irq(&l3->list_lock);
1250 /* free slabs belonging to this node */
1251 __node_shrink(cachep, node);
1252 spin_unlock_irq(&l3->list_lock);
1254 mutex_unlock(&cache_chain_mutex);
1260 mutex_unlock(&cache_chain_mutex);
1264 static struct notifier_block cpucache_notifier = { &cpuup_callback, NULL, 0 };
1267 * swap the static kmem_list3 with kmalloced memory
1269 static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
1272 struct kmem_list3 *ptr;
1274 BUG_ON(cachep->nodelists[nodeid] != list);
1275 ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, nodeid);
1278 local_irq_disable();
1279 memcpy(ptr, list, sizeof(struct kmem_list3));
1280 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1281 cachep->nodelists[nodeid] = ptr;
1286 * Initialisation. Called after the page allocator have been initialised and
1287 * before smp_init().
1289 void __init kmem_cache_init(void)
1292 struct cache_sizes *sizes;
1293 struct cache_names *names;
1297 for (i = 0; i < NUM_INIT_LISTS; i++) {
1298 kmem_list3_init(&initkmem_list3[i]);
1299 if (i < MAX_NUMNODES)
1300 cache_cache.nodelists[i] = NULL;
1304 * Fragmentation resistance on low memory - only use bigger
1305 * page orders on machines with more than 32MB of memory.
1307 if (num_physpages > (32 << 20) >> PAGE_SHIFT)
1308 slab_break_gfp_order = BREAK_GFP_ORDER_HI;
1310 /* Bootstrap is tricky, because several objects are allocated
1311 * from caches that do not exist yet:
1312 * 1) initialize the cache_cache cache: it contains the struct
1313 * kmem_cache structures of all caches, except cache_cache itself:
1314 * cache_cache is statically allocated.
1315 * Initially an __init data area is used for the head array and the
1316 * kmem_list3 structures, it's replaced with a kmalloc allocated
1317 * array at the end of the bootstrap.
1318 * 2) Create the first kmalloc cache.
1319 * The struct kmem_cache for the new cache is allocated normally.
1320 * An __init data area is used for the head array.
1321 * 3) Create the remaining kmalloc caches, with minimally sized
1323 * 4) Replace the __init data head arrays for cache_cache and the first
1324 * kmalloc cache with kmalloc allocated arrays.
1325 * 5) Replace the __init data for kmem_list3 for cache_cache and
1326 * the other cache's with kmalloc allocated memory.
1327 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1330 /* 1) create the cache_cache */
1331 INIT_LIST_HEAD(&cache_chain);
1332 list_add(&cache_cache.next, &cache_chain);
1333 cache_cache.colour_off = cache_line_size();
1334 cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
1335 cache_cache.nodelists[numa_node_id()] = &initkmem_list3[CACHE_CACHE];
1337 cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
1340 for (order = 0; order < MAX_ORDER; order++) {
1341 cache_estimate(order, cache_cache.buffer_size,
1342 cache_line_size(), 0, &left_over, &cache_cache.num);
1343 if (cache_cache.num)
1346 BUG_ON(!cache_cache.num);
1347 cache_cache.gfporder = order;
1348 cache_cache.colour = left_over / cache_cache.colour_off;
1349 cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
1350 sizeof(struct slab), cache_line_size());
1352 /* 2+3) create the kmalloc caches */
1353 sizes = malloc_sizes;
1354 names = cache_names;
1357 * Initialize the caches that provide memory for the array cache and the
1358 * kmem_list3 structures first. Without this, further allocations will
1362 sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name,
1363 sizes[INDEX_AC].cs_size,
1364 ARCH_KMALLOC_MINALIGN,
1365 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1368 if (INDEX_AC != INDEX_L3) {
1369 sizes[INDEX_L3].cs_cachep =
1370 kmem_cache_create(names[INDEX_L3].name,
1371 sizes[INDEX_L3].cs_size,
1372 ARCH_KMALLOC_MINALIGN,
1373 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1377 while (sizes->cs_size != ULONG_MAX) {
1379 * For performance, all the general caches are L1 aligned.
1380 * This should be particularly beneficial on SMP boxes, as it
1381 * eliminates "false sharing".
1382 * Note for systems short on memory removing the alignment will
1383 * allow tighter packing of the smaller caches.
1385 if (!sizes->cs_cachep) {
1386 sizes->cs_cachep = kmem_cache_create(names->name,
1388 ARCH_KMALLOC_MINALIGN,
1389 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1393 sizes->cs_dmacachep = kmem_cache_create(names->name_dma,
1395 ARCH_KMALLOC_MINALIGN,
1396 ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
1402 /* 4) Replace the bootstrap head arrays */
1406 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1408 local_irq_disable();
1409 BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
1410 memcpy(ptr, cpu_cache_get(&cache_cache),
1411 sizeof(struct arraycache_init));
1412 cache_cache.array[smp_processor_id()] = ptr;
1415 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1417 local_irq_disable();
1418 BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
1419 != &initarray_generic.cache);
1420 memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
1421 sizeof(struct arraycache_init));
1422 malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
1426 /* 5) Replace the bootstrap kmem_list3's */
1429 /* Replace the static kmem_list3 structures for the boot cpu */
1430 init_list(&cache_cache, &initkmem_list3[CACHE_CACHE],
1433 for_each_online_node(node) {
1434 init_list(malloc_sizes[INDEX_AC].cs_cachep,
1435 &initkmem_list3[SIZE_AC + node], node);
1437 if (INDEX_AC != INDEX_L3) {
1438 init_list(malloc_sizes[INDEX_L3].cs_cachep,
1439 &initkmem_list3[SIZE_L3 + node],
1445 /* 6) resize the head arrays to their final sizes */
1447 struct kmem_cache *cachep;
1448 mutex_lock(&cache_chain_mutex);
1449 list_for_each_entry(cachep, &cache_chain, next)
1450 enable_cpucache(cachep);
1451 mutex_unlock(&cache_chain_mutex);
1455 g_cpucache_up = FULL;
1458 * Register a cpu startup notifier callback that initializes
1459 * cpu_cache_get for all new cpus
1461 register_cpu_notifier(&cpucache_notifier);
1464 * The reap timers are started later, with a module init call: That part
1465 * of the kernel is not yet operational.
1469 static int __init cpucache_init(void)
1474 * Register the timers that return unneeded pages to the page allocator
1476 for_each_online_cpu(cpu)
1477 start_cpu_timer(cpu);
1480 __initcall(cpucache_init);
1483 * Interface to system's page allocator. No need to hold the cache-lock.
1485 * If we requested dmaable memory, we will get it. Even if we
1486 * did not request dmaable memory, we might get it, but that
1487 * would be relatively rare and ignorable.
1489 static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
1497 * Nommu uses slab's for process anonymous memory allocations, and thus
1498 * requires __GFP_COMP to properly refcount higher order allocations
1500 flags |= __GFP_COMP;
1502 flags |= cachep->gfpflags;
1504 page = alloc_pages_node(nodeid, flags, cachep->gfporder);
1508 nr_pages = (1 << cachep->gfporder);
1509 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1510 atomic_add(nr_pages, &slab_reclaim_pages);
1511 add_page_state(nr_slab, nr_pages);
1512 for (i = 0; i < nr_pages; i++)
1513 __SetPageSlab(page + i);
1514 return page_address(page);
1518 * Interface to system's page release.
1520 static void kmem_freepages(struct kmem_cache *cachep, void *addr)
1522 unsigned long i = (1 << cachep->gfporder);
1523 struct page *page = virt_to_page(addr);
1524 const unsigned long nr_freed = i;
1527 BUG_ON(!PageSlab(page));
1528 __ClearPageSlab(page);
1531 sub_page_state(nr_slab, nr_freed);
1532 if (current->reclaim_state)
1533 current->reclaim_state->reclaimed_slab += nr_freed;
1534 free_pages((unsigned long)addr, cachep->gfporder);
1535 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1536 atomic_sub(1 << cachep->gfporder, &slab_reclaim_pages);
1539 static void kmem_rcu_free(struct rcu_head *head)
1541 struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
1542 struct kmem_cache *cachep = slab_rcu->cachep;
1544 kmem_freepages(cachep, slab_rcu->addr);
1545 if (OFF_SLAB(cachep))
1546 kmem_cache_free(cachep->slabp_cache, slab_rcu);
1551 #ifdef CONFIG_DEBUG_PAGEALLOC
1552 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1553 unsigned long caller)
1555 int size = obj_size(cachep);
1557 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1559 if (size < 5 * sizeof(unsigned long))
1562 *addr++ = 0x12345678;
1564 *addr++ = smp_processor_id();
1565 size -= 3 * sizeof(unsigned long);
1567 unsigned long *sptr = &caller;
1568 unsigned long svalue;
1570 while (!kstack_end(sptr)) {
1572 if (kernel_text_address(svalue)) {
1574 size -= sizeof(unsigned long);
1575 if (size <= sizeof(unsigned long))
1581 *addr++ = 0x87654321;
1585 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1587 int size = obj_size(cachep);
1588 addr = &((char *)addr)[obj_offset(cachep)];
1590 memset(addr, val, size);
1591 *(unsigned char *)(addr + size - 1) = POISON_END;
1594 static void dump_line(char *data, int offset, int limit)
1597 printk(KERN_ERR "%03x:", offset);
1598 for (i = 0; i < limit; i++)
1599 printk(" %02x", (unsigned char)data[offset + i]);
1606 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1611 if (cachep->flags & SLAB_RED_ZONE) {
1612 printk(KERN_ERR "Redzone: 0x%lx/0x%lx.\n",
1613 *dbg_redzone1(cachep, objp),
1614 *dbg_redzone2(cachep, objp));
1617 if (cachep->flags & SLAB_STORE_USER) {
1618 printk(KERN_ERR "Last user: [<%p>]",
1619 *dbg_userword(cachep, objp));
1620 print_symbol("(%s)",
1621 (unsigned long)*dbg_userword(cachep, objp));
1624 realobj = (char *)objp + obj_offset(cachep);
1625 size = obj_size(cachep);
1626 for (i = 0; i < size && lines; i += 16, lines--) {
1629 if (i + limit > size)
1631 dump_line(realobj, i, limit);
1635 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1641 realobj = (char *)objp + obj_offset(cachep);
1642 size = obj_size(cachep);
1644 for (i = 0; i < size; i++) {
1645 char exp = POISON_FREE;
1648 if (realobj[i] != exp) {
1654 "Slab corruption: start=%p, len=%d\n",
1656 print_objinfo(cachep, objp, 0);
1658 /* Hexdump the affected line */
1661 if (i + limit > size)
1663 dump_line(realobj, i, limit);
1666 /* Limit to 5 lines */
1672 /* Print some data about the neighboring objects, if they
1675 struct slab *slabp = virt_to_slab(objp);
1678 objnr = obj_to_index(cachep, slabp, objp);
1680 objp = index_to_obj(cachep, slabp, objnr - 1);
1681 realobj = (char *)objp + obj_offset(cachep);
1682 printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1684 print_objinfo(cachep, objp, 2);
1686 if (objnr + 1 < cachep->num) {
1687 objp = index_to_obj(cachep, slabp, objnr + 1);
1688 realobj = (char *)objp + obj_offset(cachep);
1689 printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1691 print_objinfo(cachep, objp, 2);
1699 * slab_destroy_objs - destroy a slab and its objects
1700 * @cachep: cache pointer being destroyed
1701 * @slabp: slab pointer being destroyed
1703 * Call the registered destructor for each object in a slab that is being
1706 static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
1709 for (i = 0; i < cachep->num; i++) {
1710 void *objp = index_to_obj(cachep, slabp, i);
1712 if (cachep->flags & SLAB_POISON) {
1713 #ifdef CONFIG_DEBUG_PAGEALLOC
1714 if (cachep->buffer_size % PAGE_SIZE == 0 &&
1716 kernel_map_pages(virt_to_page(objp),
1717 cachep->buffer_size / PAGE_SIZE, 1);
1719 check_poison_obj(cachep, objp);
1721 check_poison_obj(cachep, objp);
1724 if (cachep->flags & SLAB_RED_ZONE) {
1725 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1726 slab_error(cachep, "start of a freed object "
1728 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1729 slab_error(cachep, "end of a freed object "
1732 if (cachep->dtor && !(cachep->flags & SLAB_POISON))
1733 (cachep->dtor) (objp + obj_offset(cachep), cachep, 0);
1737 static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
1741 for (i = 0; i < cachep->num; i++) {
1742 void *objp = index_to_obj(cachep, slabp, i);
1743 (cachep->dtor) (objp, cachep, 0);
1750 * slab_destroy - destroy and release all objects in a slab
1751 * @cachep: cache pointer being destroyed
1752 * @slabp: slab pointer being destroyed
1754 * Destroy all the objs in a slab, and release the mem back to the system.
1755 * Before calling the slab must have been unlinked from the cache. The
1756 * cache-lock is not held/needed.
1758 static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
1760 void *addr = slabp->s_mem - slabp->colouroff;
1762 slab_destroy_objs(cachep, slabp);
1763 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
1764 struct slab_rcu *slab_rcu;
1766 slab_rcu = (struct slab_rcu *)slabp;
1767 slab_rcu->cachep = cachep;
1768 slab_rcu->addr = addr;
1769 call_rcu(&slab_rcu->head, kmem_rcu_free);
1771 kmem_freepages(cachep, addr);
1772 if (OFF_SLAB(cachep))
1773 kmem_cache_free(cachep->slabp_cache, slabp);
1778 * For setting up all the kmem_list3s for cache whose buffer_size is same as
1779 * size of kmem_list3.
1781 static void set_up_list3s(struct kmem_cache *cachep, int index)
1785 for_each_online_node(node) {
1786 cachep->nodelists[node] = &initkmem_list3[index + node];
1787 cachep->nodelists[node]->next_reap = jiffies +
1789 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1794 * calculate_slab_order - calculate size (page order) of slabs
1795 * @cachep: pointer to the cache that is being created
1796 * @size: size of objects to be created in this cache.
1797 * @align: required alignment for the objects.
1798 * @flags: slab allocation flags
1800 * Also calculates the number of objects per slab.
1802 * This could be made much more intelligent. For now, try to avoid using
1803 * high order pages for slabs. When the gfp() functions are more friendly
1804 * towards high-order requests, this should be changed.
1806 static size_t calculate_slab_order(struct kmem_cache *cachep,
1807 size_t size, size_t align, unsigned long flags)
1809 unsigned long offslab_limit;
1810 size_t left_over = 0;
1813 for (gfporder = 0; gfporder <= MAX_GFP_ORDER; gfporder++) {
1817 cache_estimate(gfporder, size, align, flags, &remainder, &num);
1821 if (flags & CFLGS_OFF_SLAB) {
1823 * Max number of objs-per-slab for caches which
1824 * use off-slab slabs. Needed to avoid a possible
1825 * looping condition in cache_grow().
1827 offslab_limit = size - sizeof(struct slab);
1828 offslab_limit /= sizeof(kmem_bufctl_t);
1830 if (num > offslab_limit)
1834 /* Found something acceptable - save it away */
1836 cachep->gfporder = gfporder;
1837 left_over = remainder;
1840 * A VFS-reclaimable slab tends to have most allocations
1841 * as GFP_NOFS and we really don't want to have to be allocating
1842 * higher-order pages when we are unable to shrink dcache.
1844 if (flags & SLAB_RECLAIM_ACCOUNT)
1848 * Large number of objects is good, but very large slabs are
1849 * currently bad for the gfp()s.
1851 if (gfporder >= slab_break_gfp_order)
1855 * Acceptable internal fragmentation?
1857 if (left_over * 8 <= (PAGE_SIZE << gfporder))
1863 static void setup_cpu_cache(struct kmem_cache *cachep)
1865 if (g_cpucache_up == FULL) {
1866 enable_cpucache(cachep);
1869 if (g_cpucache_up == NONE) {
1871 * Note: the first kmem_cache_create must create the cache
1872 * that's used by kmalloc(24), otherwise the creation of
1873 * further caches will BUG().
1875 cachep->array[smp_processor_id()] = &initarray_generic.cache;
1878 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
1879 * the first cache, then we need to set up all its list3s,
1880 * otherwise the creation of further caches will BUG().
1882 set_up_list3s(cachep, SIZE_AC);
1883 if (INDEX_AC == INDEX_L3)
1884 g_cpucache_up = PARTIAL_L3;
1886 g_cpucache_up = PARTIAL_AC;
1888 cachep->array[smp_processor_id()] =
1889 kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1891 if (g_cpucache_up == PARTIAL_AC) {
1892 set_up_list3s(cachep, SIZE_L3);
1893 g_cpucache_up = PARTIAL_L3;
1896 for_each_online_node(node) {
1897 cachep->nodelists[node] =
1898 kmalloc_node(sizeof(struct kmem_list3),
1900 BUG_ON(!cachep->nodelists[node]);
1901 kmem_list3_init(cachep->nodelists[node]);
1905 cachep->nodelists[numa_node_id()]->next_reap =
1906 jiffies + REAPTIMEOUT_LIST3 +
1907 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1909 cpu_cache_get(cachep)->avail = 0;
1910 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
1911 cpu_cache_get(cachep)->batchcount = 1;
1912 cpu_cache_get(cachep)->touched = 0;
1913 cachep->batchcount = 1;
1914 cachep->limit = BOOT_CPUCACHE_ENTRIES;
1918 * kmem_cache_create - Create a cache.
1919 * @name: A string which is used in /proc/slabinfo to identify this cache.
1920 * @size: The size of objects to be created in this cache.
1921 * @align: The required alignment for the objects.
1922 * @flags: SLAB flags
1923 * @ctor: A constructor for the objects.
1924 * @dtor: A destructor for the objects.
1926 * Returns a ptr to the cache on success, NULL on failure.
1927 * Cannot be called within a int, but can be interrupted.
1928 * The @ctor is run when new pages are allocated by the cache
1929 * and the @dtor is run before the pages are handed back.
1931 * @name must be valid until the cache is destroyed. This implies that
1932 * the module calling this has to destroy the cache before getting unloaded.
1936 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
1937 * to catch references to uninitialised memory.
1939 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
1940 * for buffer overruns.
1942 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
1943 * cacheline. This can be beneficial if you're counting cycles as closely
1947 kmem_cache_create (const char *name, size_t size, size_t align,
1948 unsigned long flags,
1949 void (*ctor)(void*, struct kmem_cache *, unsigned long),
1950 void (*dtor)(void*, struct kmem_cache *, unsigned long))
1952 size_t left_over, slab_size, ralign;
1953 struct kmem_cache *cachep = NULL, *pc;
1956 * Sanity checks... these are all serious usage bugs.
1958 if (!name || in_interrupt() || (size < BYTES_PER_WORD) ||
1959 (size > (1 << MAX_OBJ_ORDER) * PAGE_SIZE) || (dtor && !ctor)) {
1960 printk(KERN_ERR "%s: Early error in slab %s\n", __FUNCTION__,
1966 * Prevent CPUs from coming and going.
1967 * lock_cpu_hotplug() nests outside cache_chain_mutex
1971 mutex_lock(&cache_chain_mutex);
1973 list_for_each_entry(pc, &cache_chain, next) {
1974 mm_segment_t old_fs = get_fs();
1979 * This happens when the module gets unloaded and doesn't
1980 * destroy its slab cache and no-one else reuses the vmalloc
1981 * area of the module. Print a warning.
1984 res = __get_user(tmp, pc->name);
1987 printk("SLAB: cache with size %d has lost its name\n",
1992 if (!strcmp(pc->name, name)) {
1993 printk("kmem_cache_create: duplicate cache %s\n", name);
2000 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
2001 if ((flags & SLAB_DEBUG_INITIAL) && !ctor) {
2002 /* No constructor, but inital state check requested */
2003 printk(KERN_ERR "%s: No con, but init state check "
2004 "requested - %s\n", __FUNCTION__, name);
2005 flags &= ~SLAB_DEBUG_INITIAL;
2009 * Enable redzoning and last user accounting, except for caches with
2010 * large objects, if the increased size would increase the object size
2011 * above the next power of two: caches with object sizes just above a
2012 * power of two have a significant amount of internal fragmentation.
2014 if (size < 4096 || fls(size - 1) == fls(size-1 + 3 * BYTES_PER_WORD))
2015 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2016 if (!(flags & SLAB_DESTROY_BY_RCU))
2017 flags |= SLAB_POISON;
2019 if (flags & SLAB_DESTROY_BY_RCU)
2020 BUG_ON(flags & SLAB_POISON);
2022 if (flags & SLAB_DESTROY_BY_RCU)
2026 * Always checks flags, a caller might be expecting debug support which
2029 BUG_ON(flags & ~CREATE_MASK);
2032 * Check that size is in terms of words. This is needed to avoid
2033 * unaligned accesses for some archs when redzoning is used, and makes
2034 * sure any on-slab bufctl's are also correctly aligned.
2036 if (size & (BYTES_PER_WORD - 1)) {
2037 size += (BYTES_PER_WORD - 1);
2038 size &= ~(BYTES_PER_WORD - 1);
2041 /* calculate the final buffer alignment: */
2043 /* 1) arch recommendation: can be overridden for debug */
2044 if (flags & SLAB_HWCACHE_ALIGN) {
2046 * Default alignment: as specified by the arch code. Except if
2047 * an object is really small, then squeeze multiple objects into
2050 ralign = cache_line_size();
2051 while (size <= ralign / 2)
2054 ralign = BYTES_PER_WORD;
2056 /* 2) arch mandated alignment: disables debug if necessary */
2057 if (ralign < ARCH_SLAB_MINALIGN) {
2058 ralign = ARCH_SLAB_MINALIGN;
2059 if (ralign > BYTES_PER_WORD)
2060 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2062 /* 3) caller mandated alignment: disables debug if necessary */
2063 if (ralign < align) {
2065 if (ralign > BYTES_PER_WORD)
2066 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2069 * 4) Store it. Note that the debug code below can reduce
2070 * the alignment to BYTES_PER_WORD.
2074 /* Get cache's description obj. */
2075 cachep = kmem_cache_zalloc(&cache_cache, SLAB_KERNEL);
2080 cachep->obj_size = size;
2082 if (flags & SLAB_RED_ZONE) {
2083 /* redzoning only works with word aligned caches */
2084 align = BYTES_PER_WORD;
2086 /* add space for red zone words */
2087 cachep->obj_offset += BYTES_PER_WORD;
2088 size += 2 * BYTES_PER_WORD;
2090 if (flags & SLAB_STORE_USER) {
2091 /* user store requires word alignment and
2092 * one word storage behind the end of the real
2095 align = BYTES_PER_WORD;
2096 size += BYTES_PER_WORD;
2098 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2099 if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
2100 && cachep->obj_size > cache_line_size() && size < PAGE_SIZE) {
2101 cachep->obj_offset += PAGE_SIZE - size;
2107 /* Determine if the slab management is 'on' or 'off' slab. */
2108 if (size >= (PAGE_SIZE >> 3))
2110 * Size is large, assume best to place the slab management obj
2111 * off-slab (should allow better packing of objs).
2113 flags |= CFLGS_OFF_SLAB;
2115 size = ALIGN(size, align);
2117 left_over = calculate_slab_order(cachep, size, align, flags);
2120 printk("kmem_cache_create: couldn't create cache %s.\n", name);
2121 kmem_cache_free(&cache_cache, cachep);
2125 slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
2126 + sizeof(struct slab), align);
2129 * If the slab has been placed off-slab, and we have enough space then
2130 * move it on-slab. This is at the expense of any extra colouring.
2132 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
2133 flags &= ~CFLGS_OFF_SLAB;
2134 left_over -= slab_size;
2137 if (flags & CFLGS_OFF_SLAB) {
2138 /* really off slab. No need for manual alignment */
2140 cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
2143 cachep->colour_off = cache_line_size();
2144 /* Offset must be a multiple of the alignment. */
2145 if (cachep->colour_off < align)
2146 cachep->colour_off = align;
2147 cachep->colour = left_over / cachep->colour_off;
2148 cachep->slab_size = slab_size;
2149 cachep->flags = flags;
2150 cachep->gfpflags = 0;
2151 if (flags & SLAB_CACHE_DMA)
2152 cachep->gfpflags |= GFP_DMA;
2153 cachep->buffer_size = size;
2155 if (flags & CFLGS_OFF_SLAB)
2156 cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
2157 cachep->ctor = ctor;
2158 cachep->dtor = dtor;
2159 cachep->name = name;
2162 setup_cpu_cache(cachep);
2164 /* cache setup completed, link it into the list */
2165 list_add(&cachep->next, &cache_chain);
2167 if (!cachep && (flags & SLAB_PANIC))
2168 panic("kmem_cache_create(): failed to create slab `%s'\n",
2170 mutex_unlock(&cache_chain_mutex);
2171 unlock_cpu_hotplug();
2174 EXPORT_SYMBOL(kmem_cache_create);
2177 static void check_irq_off(void)
2179 BUG_ON(!irqs_disabled());
2182 static void check_irq_on(void)
2184 BUG_ON(irqs_disabled());
2187 static void check_spinlock_acquired(struct kmem_cache *cachep)
2191 assert_spin_locked(&cachep->nodelists[numa_node_id()]->list_lock);
2195 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2199 assert_spin_locked(&cachep->nodelists[node]->list_lock);
2204 #define check_irq_off() do { } while(0)
2205 #define check_irq_on() do { } while(0)
2206 #define check_spinlock_acquired(x) do { } while(0)
2207 #define check_spinlock_acquired_node(x, y) do { } while(0)
2210 static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
2211 struct array_cache *ac,
2212 int force, int node);
2214 static void do_drain(void *arg)
2216 struct kmem_cache *cachep = arg;
2217 struct array_cache *ac;
2218 int node = numa_node_id();
2221 ac = cpu_cache_get(cachep);
2222 spin_lock(&cachep->nodelists[node]->list_lock);
2223 free_block(cachep, ac->entry, ac->avail, node);
2224 spin_unlock(&cachep->nodelists[node]->list_lock);
2228 static void drain_cpu_caches(struct kmem_cache *cachep)
2230 struct kmem_list3 *l3;
2233 on_each_cpu(do_drain, cachep, 1, 1);
2235 for_each_online_node(node) {
2236 l3 = cachep->nodelists[node];
2237 if (l3 && l3->alien)
2238 drain_alien_cache(cachep, l3->alien);
2241 for_each_online_node(node) {
2242 l3 = cachep->nodelists[node];
2244 drain_array(cachep, l3, l3->shared, 1, node);
2248 static int __node_shrink(struct kmem_cache *cachep, int node)
2251 struct kmem_list3 *l3 = cachep->nodelists[node];
2255 struct list_head *p;
2257 p = l3->slabs_free.prev;
2258 if (p == &l3->slabs_free)
2261 slabp = list_entry(l3->slabs_free.prev, struct slab, list);
2263 BUG_ON(slabp->inuse);
2265 list_del(&slabp->list);
2267 l3->free_objects -= cachep->num;
2268 spin_unlock_irq(&l3->list_lock);
2269 slab_destroy(cachep, slabp);
2270 spin_lock_irq(&l3->list_lock);
2272 ret = !list_empty(&l3->slabs_full) || !list_empty(&l3->slabs_partial);
2276 static int __cache_shrink(struct kmem_cache *cachep)
2279 struct kmem_list3 *l3;
2281 drain_cpu_caches(cachep);
2284 for_each_online_node(i) {
2285 l3 = cachep->nodelists[i];
2287 spin_lock_irq(&l3->list_lock);
2288 ret += __node_shrink(cachep, i);
2289 spin_unlock_irq(&l3->list_lock);
2292 return (ret ? 1 : 0);
2296 * kmem_cache_shrink - Shrink a cache.
2297 * @cachep: The cache to shrink.
2299 * Releases as many slabs as possible for a cache.
2300 * To help debugging, a zero exit status indicates all slabs were released.
2302 int kmem_cache_shrink(struct kmem_cache *cachep)
2304 BUG_ON(!cachep || in_interrupt());
2306 return __cache_shrink(cachep);
2308 EXPORT_SYMBOL(kmem_cache_shrink);
2311 * kmem_cache_destroy - delete a cache
2312 * @cachep: the cache to destroy
2314 * Remove a struct kmem_cache object from the slab cache.
2315 * Returns 0 on success.
2317 * It is expected this function will be called by a module when it is
2318 * unloaded. This will remove the cache completely, and avoid a duplicate
2319 * cache being allocated each time a module is loaded and unloaded, if the
2320 * module doesn't have persistent in-kernel storage across loads and unloads.
2322 * The cache must be empty before calling this function.
2324 * The caller must guarantee that noone will allocate memory from the cache
2325 * during the kmem_cache_destroy().
2327 int kmem_cache_destroy(struct kmem_cache *cachep)
2330 struct kmem_list3 *l3;
2332 BUG_ON(!cachep || in_interrupt());
2334 /* Don't let CPUs to come and go */
2337 /* Find the cache in the chain of caches. */
2338 mutex_lock(&cache_chain_mutex);
2340 * the chain is never empty, cache_cache is never destroyed
2342 list_del(&cachep->next);
2343 mutex_unlock(&cache_chain_mutex);
2345 if (__cache_shrink(cachep)) {
2346 slab_error(cachep, "Can't free all objects");
2347 mutex_lock(&cache_chain_mutex);
2348 list_add(&cachep->next, &cache_chain);
2349 mutex_unlock(&cache_chain_mutex);
2350 unlock_cpu_hotplug();
2354 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
2357 for_each_online_cpu(i)
2358 kfree(cachep->array[i]);
2360 /* NUMA: free the list3 structures */
2361 for_each_online_node(i) {
2362 l3 = cachep->nodelists[i];
2365 free_alien_cache(l3->alien);
2369 kmem_cache_free(&cache_cache, cachep);
2370 unlock_cpu_hotplug();
2373 EXPORT_SYMBOL(kmem_cache_destroy);
2375 /* Get the memory for a slab management obj. */
2376 static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,
2377 int colour_off, gfp_t local_flags,
2382 if (OFF_SLAB(cachep)) {
2383 /* Slab management obj is off-slab. */
2384 slabp = kmem_cache_alloc_node(cachep->slabp_cache,
2385 local_flags, nodeid);
2389 slabp = objp + colour_off;
2390 colour_off += cachep->slab_size;
2393 slabp->colouroff = colour_off;
2394 slabp->s_mem = objp + colour_off;
2395 slabp->nodeid = nodeid;
2399 static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
2401 return (kmem_bufctl_t *) (slabp + 1);
2404 static void cache_init_objs(struct kmem_cache *cachep,
2405 struct slab *slabp, unsigned long ctor_flags)
2409 for (i = 0; i < cachep->num; i++) {
2410 void *objp = index_to_obj(cachep, slabp, i);
2412 /* need to poison the objs? */
2413 if (cachep->flags & SLAB_POISON)
2414 poison_obj(cachep, objp, POISON_FREE);
2415 if (cachep->flags & SLAB_STORE_USER)
2416 *dbg_userword(cachep, objp) = NULL;
2418 if (cachep->flags & SLAB_RED_ZONE) {
2419 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2420 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2423 * Constructors are not allowed to allocate memory from the same
2424 * cache which they are a constructor for. Otherwise, deadlock.
2425 * They must also be threaded.
2427 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2428 cachep->ctor(objp + obj_offset(cachep), cachep,
2431 if (cachep->flags & SLAB_RED_ZONE) {
2432 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2433 slab_error(cachep, "constructor overwrote the"
2434 " end of an object");
2435 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2436 slab_error(cachep, "constructor overwrote the"
2437 " start of an object");
2439 if ((cachep->buffer_size % PAGE_SIZE) == 0 &&
2440 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2441 kernel_map_pages(virt_to_page(objp),
2442 cachep->buffer_size / PAGE_SIZE, 0);
2445 cachep->ctor(objp, cachep, ctor_flags);
2447 slab_bufctl(slabp)[i] = i + 1;
2449 slab_bufctl(slabp)[i - 1] = BUFCTL_END;
2453 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2455 if (flags & SLAB_DMA)
2456 BUG_ON(!(cachep->gfpflags & GFP_DMA));
2458 BUG_ON(cachep->gfpflags & GFP_DMA);
2461 static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
2464 void *objp = index_to_obj(cachep, slabp, slabp->free);
2468 next = slab_bufctl(slabp)[slabp->free];
2470 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2471 WARN_ON(slabp->nodeid != nodeid);
2478 static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
2479 void *objp, int nodeid)
2481 unsigned int objnr = obj_to_index(cachep, slabp, objp);
2484 /* Verify that the slab belongs to the intended node */
2485 WARN_ON(slabp->nodeid != nodeid);
2487 if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
2488 printk(KERN_ERR "slab: double free detected in cache "
2489 "'%s', objp %p\n", cachep->name, objp);
2493 slab_bufctl(slabp)[objnr] = slabp->free;
2494 slabp->free = objnr;
2499 * Map pages beginning at addr to the given cache and slab. This is required
2500 * for the slab allocator to be able to lookup the cache and slab of a
2501 * virtual address for kfree, ksize, kmem_ptr_validate, and slab debugging.
2503 static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
2509 page = virt_to_page(addr);
2512 if (likely(!PageCompound(page)))
2513 nr_pages <<= cache->gfporder;
2516 page_set_cache(page, cache);
2517 page_set_slab(page, slab);
2519 } while (--nr_pages);
2523 * Grow (by 1) the number of slabs within a cache. This is called by
2524 * kmem_cache_alloc() when there are no active objs left in a cache.
2526 static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid)
2532 unsigned long ctor_flags;
2533 struct kmem_list3 *l3;
2536 * Be lazy and only check for valid flags here, keeping it out of the
2537 * critical path in kmem_cache_alloc().
2539 BUG_ON(flags & ~(SLAB_DMA | SLAB_LEVEL_MASK | SLAB_NO_GROW));
2540 if (flags & SLAB_NO_GROW)
2543 ctor_flags = SLAB_CTOR_CONSTRUCTOR;
2544 local_flags = (flags & SLAB_LEVEL_MASK);
2545 if (!(local_flags & __GFP_WAIT))
2547 * Not allowed to sleep. Need to tell a constructor about
2548 * this - it might need to know...
2550 ctor_flags |= SLAB_CTOR_ATOMIC;
2552 /* Take the l3 list lock to change the colour_next on this node */
2554 l3 = cachep->nodelists[nodeid];
2555 spin_lock(&l3->list_lock);
2557 /* Get colour for the slab, and cal the next value. */
2558 offset = l3->colour_next;
2560 if (l3->colour_next >= cachep->colour)
2561 l3->colour_next = 0;
2562 spin_unlock(&l3->list_lock);
2564 offset *= cachep->colour_off;
2566 if (local_flags & __GFP_WAIT)
2570 * The test for missing atomic flag is performed here, rather than
2571 * the more obvious place, simply to reduce the critical path length
2572 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2573 * will eventually be caught here (where it matters).
2575 kmem_flagcheck(cachep, flags);
2578 * Get mem for the objs. Attempt to allocate a physical page from
2581 objp = kmem_getpages(cachep, flags, nodeid);
2585 /* Get slab management. */
2586 slabp = alloc_slabmgmt(cachep, objp, offset, local_flags, nodeid);
2590 slabp->nodeid = nodeid;
2591 slab_map_pages(cachep, slabp, objp);
2593 cache_init_objs(cachep, slabp, ctor_flags);
2595 if (local_flags & __GFP_WAIT)
2596 local_irq_disable();
2598 spin_lock(&l3->list_lock);
2600 /* Make slab active. */
2601 list_add_tail(&slabp->list, &(l3->slabs_free));
2602 STATS_INC_GROWN(cachep);
2603 l3->free_objects += cachep->num;
2604 spin_unlock(&l3->list_lock);
2607 kmem_freepages(cachep, objp);
2609 if (local_flags & __GFP_WAIT)
2610 local_irq_disable();
2617 * Perform extra freeing checks:
2618 * - detect bad pointers.
2619 * - POISON/RED_ZONE checking
2620 * - destructor calls, for caches with POISON+dtor
2622 static void kfree_debugcheck(const void *objp)
2626 if (!virt_addr_valid(objp)) {
2627 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2628 (unsigned long)objp);
2631 page = virt_to_page(objp);
2632 if (!PageSlab(page)) {
2633 printk(KERN_ERR "kfree_debugcheck: bad ptr %lxh.\n",
2634 (unsigned long)objp);
2639 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2646 objp -= obj_offset(cachep);
2647 kfree_debugcheck(objp);
2648 page = virt_to_page(objp);
2650 if (page_get_cache(page) != cachep) {
2651 printk(KERN_ERR "mismatch in kmem_cache_free: expected "
2652 "cache %p, got %p\n",
2653 page_get_cache(page), cachep);
2654 printk(KERN_ERR "%p is %s.\n", cachep, cachep->name);
2655 printk(KERN_ERR "%p is %s.\n", page_get_cache(page),
2656 page_get_cache(page)->name);
2659 slabp = page_get_slab(page);
2661 if (cachep->flags & SLAB_RED_ZONE) {
2662 if (*dbg_redzone1(cachep, objp) != RED_ACTIVE ||
2663 *dbg_redzone2(cachep, objp) != RED_ACTIVE) {
2664 slab_error(cachep, "double free, or memory outside"
2665 " object was overwritten");
2666 printk(KERN_ERR "%p: redzone 1:0x%lx, "
2667 "redzone 2:0x%lx.\n",
2668 objp, *dbg_redzone1(cachep, objp),
2669 *dbg_redzone2(cachep, objp));
2671 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2672 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2674 if (cachep->flags & SLAB_STORE_USER)
2675 *dbg_userword(cachep, objp) = caller;
2677 objnr = obj_to_index(cachep, slabp, objp);
2679 BUG_ON(objnr >= cachep->num);
2680 BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
2682 if (cachep->flags & SLAB_DEBUG_INITIAL) {
2684 * Need to call the slab's constructor so the caller can
2685 * perform a verify of its state (debugging). Called without
2686 * the cache-lock held.
2688 cachep->ctor(objp + obj_offset(cachep),
2689 cachep, SLAB_CTOR_CONSTRUCTOR | SLAB_CTOR_VERIFY);
2691 if (cachep->flags & SLAB_POISON && cachep->dtor) {
2692 /* we want to cache poison the object,
2693 * call the destruction callback
2695 cachep->dtor(objp + obj_offset(cachep), cachep, 0);
2697 #ifdef CONFIG_DEBUG_SLAB_LEAK
2698 slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
2700 if (cachep->flags & SLAB_POISON) {
2701 #ifdef CONFIG_DEBUG_PAGEALLOC
2702 if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2703 store_stackinfo(cachep, objp, (unsigned long)caller);
2704 kernel_map_pages(virt_to_page(objp),
2705 cachep->buffer_size / PAGE_SIZE, 0);
2707 poison_obj(cachep, objp, POISON_FREE);
2710 poison_obj(cachep, objp, POISON_FREE);
2716 static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
2721 /* Check slab's freelist to see if this obj is there. */
2722 for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
2724 if (entries > cachep->num || i >= cachep->num)
2727 if (entries != cachep->num - slabp->inuse) {
2729 printk(KERN_ERR "slab: Internal list corruption detected in "
2730 "cache '%s'(%d), slabp %p(%d). Hexdump:\n",
2731 cachep->name, cachep->num, slabp, slabp->inuse);
2733 i < sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t);
2736 printk("\n%03x:", i);
2737 printk(" %02x", ((unsigned char *)slabp)[i]);
2744 #define kfree_debugcheck(x) do { } while(0)
2745 #define cache_free_debugcheck(x,objp,z) (objp)
2746 #define check_slabp(x,y) do { } while(0)
2749 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
2752 struct kmem_list3 *l3;
2753 struct array_cache *ac;
2756 ac = cpu_cache_get(cachep);
2758 batchcount = ac->batchcount;
2759 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2761 * If there was little recent activity on this cache, then
2762 * perform only a partial refill. Otherwise we could generate
2765 batchcount = BATCHREFILL_LIMIT;
2767 l3 = cachep->nodelists[numa_node_id()];
2769 BUG_ON(ac->avail > 0 || !l3);
2770 spin_lock(&l3->list_lock);
2772 /* See if we can refill from the shared array */
2773 if (l3->shared && transfer_objects(ac, l3->shared, batchcount))
2776 while (batchcount > 0) {
2777 struct list_head *entry;
2779 /* Get slab alloc is to come from. */
2780 entry = l3->slabs_partial.next;
2781 if (entry == &l3->slabs_partial) {
2782 l3->free_touched = 1;
2783 entry = l3->slabs_free.next;
2784 if (entry == &l3->slabs_free)
2788 slabp = list_entry(entry, struct slab, list);
2789 check_slabp(cachep, slabp);
2790 check_spinlock_acquired(cachep);
2791 while (slabp->inuse < cachep->num && batchcount--) {
2792 STATS_INC_ALLOCED(cachep);
2793 STATS_INC_ACTIVE(cachep);
2794 STATS_SET_HIGH(cachep);
2796 ac->entry[ac->avail++] = slab_get_obj(cachep, slabp,
2799 check_slabp(cachep, slabp);
2801 /* move slabp to correct slabp list: */
2802 list_del(&slabp->list);
2803 if (slabp->free == BUFCTL_END)
2804 list_add(&slabp->list, &l3->slabs_full);
2806 list_add(&slabp->list, &l3->slabs_partial);
2810 l3->free_objects -= ac->avail;
2812 spin_unlock(&l3->list_lock);
2814 if (unlikely(!ac->avail)) {
2816 x = cache_grow(cachep, flags, numa_node_id());
2818 /* cache_grow can reenable interrupts, then ac could change. */
2819 ac = cpu_cache_get(cachep);
2820 if (!x && ac->avail == 0) /* no objects in sight? abort */
2823 if (!ac->avail) /* objects refilled by interrupt? */
2827 return ac->entry[--ac->avail];
2830 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
2833 might_sleep_if(flags & __GFP_WAIT);
2835 kmem_flagcheck(cachep, flags);
2840 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
2841 gfp_t flags, void *objp, void *caller)
2845 if (cachep->flags & SLAB_POISON) {
2846 #ifdef CONFIG_DEBUG_PAGEALLOC
2847 if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
2848 kernel_map_pages(virt_to_page(objp),
2849 cachep->buffer_size / PAGE_SIZE, 1);
2851 check_poison_obj(cachep, objp);
2853 check_poison_obj(cachep, objp);
2855 poison_obj(cachep, objp, POISON_INUSE);
2857 if (cachep->flags & SLAB_STORE_USER)
2858 *dbg_userword(cachep, objp) = caller;
2860 if (cachep->flags & SLAB_RED_ZONE) {
2861 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
2862 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
2863 slab_error(cachep, "double free, or memory outside"
2864 " object was overwritten");
2866 "%p: redzone 1:0x%lx, redzone 2:0x%lx\n",
2867 objp, *dbg_redzone1(cachep, objp),
2868 *dbg_redzone2(cachep, objp));
2870 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
2871 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
2873 #ifdef CONFIG_DEBUG_SLAB_LEAK
2878 slabp = page_get_slab(virt_to_page(objp));
2879 objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;
2880 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
2883 objp += obj_offset(cachep);
2884 if (cachep->ctor && cachep->flags & SLAB_POISON) {
2885 unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR;
2887 if (!(flags & __GFP_WAIT))
2888 ctor_flags |= SLAB_CTOR_ATOMIC;
2890 cachep->ctor(objp, cachep, ctor_flags);
2895 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
2898 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
2901 struct array_cache *ac;
2904 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
2905 objp = alternate_node_alloc(cachep, flags);
2912 ac = cpu_cache_get(cachep);
2913 if (likely(ac->avail)) {
2914 STATS_INC_ALLOCHIT(cachep);
2916 objp = ac->entry[--ac->avail];
2918 STATS_INC_ALLOCMISS(cachep);
2919 objp = cache_alloc_refill(cachep, flags);
2924 static __always_inline void *__cache_alloc(struct kmem_cache *cachep,
2925 gfp_t flags, void *caller)
2927 unsigned long save_flags;
2930 cache_alloc_debugcheck_before(cachep, flags);
2932 local_irq_save(save_flags);
2933 objp = ____cache_alloc(cachep, flags);
2934 local_irq_restore(save_flags);
2935 objp = cache_alloc_debugcheck_after(cachep, flags, objp,
2943 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
2945 * If we are in_interrupt, then process context, including cpusets and
2946 * mempolicy, may not apply and should not be used for allocation policy.
2948 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
2950 int nid_alloc, nid_here;
2954 nid_alloc = nid_here = numa_node_id();
2955 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
2956 nid_alloc = cpuset_mem_spread_node();
2957 else if (current->mempolicy)
2958 nid_alloc = slab_node(current->mempolicy);
2959 if (nid_alloc != nid_here)
2960 return __cache_alloc_node(cachep, flags, nid_alloc);
2965 * A interface to enable slab creation on nodeid
2967 static void *__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
2970 struct list_head *entry;
2972 struct kmem_list3 *l3;
2976 l3 = cachep->nodelists[nodeid];
2981 spin_lock(&l3->list_lock);
2982 entry = l3->slabs_partial.next;
2983 if (entry == &l3->slabs_partial) {
2984 l3->free_touched = 1;
2985 entry = l3->slabs_free.next;
2986 if (entry == &l3->slabs_free)
2990 slabp = list_entry(entry, struct slab, list);
2991 check_spinlock_acquired_node(cachep, nodeid);
2992 check_slabp(cachep, slabp);
2994 STATS_INC_NODEALLOCS(cachep);
2995 STATS_INC_ACTIVE(cachep);
2996 STATS_SET_HIGH(cachep);
2998 BUG_ON(slabp->inuse == cachep->num);
3000 obj = slab_get_obj(cachep, slabp, nodeid);
3001 check_slabp(cachep, slabp);
3003 /* move slabp to correct slabp list: */
3004 list_del(&slabp->list);
3006 if (slabp->free == BUFCTL_END)
3007 list_add(&slabp->list, &l3->slabs_full);
3009 list_add(&slabp->list, &l3->slabs_partial);
3011 spin_unlock(&l3->list_lock);
3015 spin_unlock(&l3->list_lock);
3016 x = cache_grow(cachep, flags, nodeid);
3028 * Caller needs to acquire correct kmem_list's list_lock
3030 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
3034 struct kmem_list3 *l3;
3036 for (i = 0; i < nr_objects; i++) {
3037 void *objp = objpp[i];
3040 slabp = virt_to_slab(objp);
3041 l3 = cachep->nodelists[node];
3042 list_del(&slabp->list);
3043 check_spinlock_acquired_node(cachep, node);
3044 check_slabp(cachep, slabp);
3045 slab_put_obj(cachep, slabp, objp, node);
3046 STATS_DEC_ACTIVE(cachep);
3048 check_slabp(cachep, slabp);
3050 /* fixup slab chains */
3051 if (slabp->inuse == 0) {
3052 if (l3->free_objects > l3->free_limit) {
3053 l3->free_objects -= cachep->num;
3054 slab_destroy(cachep, slabp);
3056 list_add(&slabp->list, &l3->slabs_free);
3059 /* Unconditionally move a slab to the end of the
3060 * partial list on free - maximum time for the
3061 * other objects to be freed, too.
3063 list_add_tail(&slabp->list, &l3->slabs_partial);
3068 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3071 struct kmem_list3 *l3;
3072 int node = numa_node_id();
3074 batchcount = ac->batchcount;
3076 BUG_ON(!batchcount || batchcount > ac->avail);
3079 l3 = cachep->nodelists[node];
3080 spin_lock(&l3->list_lock);
3082 struct array_cache *shared_array = l3->shared;
3083 int max = shared_array->limit - shared_array->avail;
3085 if (batchcount > max)
3087 memcpy(&(shared_array->entry[shared_array->avail]),
3088 ac->entry, sizeof(void *) * batchcount);
3089 shared_array->avail += batchcount;
3094 free_block(cachep, ac->entry, batchcount, node);
3099 struct list_head *p;
3101 p = l3->slabs_free.next;
3102 while (p != &(l3->slabs_free)) {
3105 slabp = list_entry(p, struct slab, list);
3106 BUG_ON(slabp->inuse);
3111 STATS_SET_FREEABLE(cachep, i);
3114 spin_unlock(&l3->list_lock);
3115 ac->avail -= batchcount;
3116 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3120 * Release an obj back to its cache. If the obj has a constructed state, it must
3121 * be in this state _before_ it is released. Called with disabled ints.
3123 static inline void __cache_free(struct kmem_cache *cachep, void *objp)
3125 struct array_cache *ac = cpu_cache_get(cachep);
3128 objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
3130 if (cache_free_alien(cachep, objp))
3133 if (likely(ac->avail < ac->limit)) {
3134 STATS_INC_FREEHIT(cachep);
3135 ac->entry[ac->avail++] = objp;
3138 STATS_INC_FREEMISS(cachep);
3139 cache_flusharray(cachep, ac);
3140 ac->entry[ac->avail++] = objp;
3145 * kmem_cache_alloc - Allocate an object
3146 * @cachep: The cache to allocate from.
3147 * @flags: See kmalloc().
3149 * Allocate an object from this cache. The flags are only relevant
3150 * if the cache has no available objects.
3152 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3154 return __cache_alloc(cachep, flags, __builtin_return_address(0));
3156 EXPORT_SYMBOL(kmem_cache_alloc);
3159 * kmem_cache_alloc - Allocate an object. The memory is set to zero.
3160 * @cache: The cache to allocate from.
3161 * @flags: See kmalloc().
3163 * Allocate an object from this cache and set the allocated memory to zero.
3164 * The flags are only relevant if the cache has no available objects.
3166 void *kmem_cache_zalloc(struct kmem_cache *cache, gfp_t flags)
3168 void *ret = __cache_alloc(cache, flags, __builtin_return_address(0));
3170 memset(ret, 0, obj_size(cache));
3173 EXPORT_SYMBOL(kmem_cache_zalloc);
3176 * kmem_ptr_validate - check if an untrusted pointer might
3178 * @cachep: the cache we're checking against
3179 * @ptr: pointer to validate
3181 * This verifies that the untrusted pointer looks sane:
3182 * it is _not_ a guarantee that the pointer is actually
3183 * part of the slab cache in question, but it at least
3184 * validates that the pointer can be dereferenced and
3185 * looks half-way sane.
3187 * Currently only used for dentry validation.
3189 int fastcall kmem_ptr_validate(struct kmem_cache *cachep, void *ptr)
3191 unsigned long addr = (unsigned long)ptr;
3192 unsigned long min_addr = PAGE_OFFSET;
3193 unsigned long align_mask = BYTES_PER_WORD - 1;
3194 unsigned long size = cachep->buffer_size;
3197 if (unlikely(addr < min_addr))
3199 if (unlikely(addr > (unsigned long)high_memory - size))
3201 if (unlikely(addr & align_mask))
3203 if (unlikely(!kern_addr_valid(addr)))
3205 if (unlikely(!kern_addr_valid(addr + size - 1)))
3207 page = virt_to_page(ptr);
3208 if (unlikely(!PageSlab(page)))
3210 if (unlikely(page_get_cache(page) != cachep))
3219 * kmem_cache_alloc_node - Allocate an object on the specified node
3220 * @cachep: The cache to allocate from.
3221 * @flags: See kmalloc().
3222 * @nodeid: node number of the target node.
3224 * Identical to kmem_cache_alloc, except that this function is slow
3225 * and can sleep. And it will allocate memory on the given node, which
3226 * can improve the performance for cpu bound structures.
3227 * New and improved: it will now make sure that the object gets
3228 * put on the correct node list so that there is no false sharing.
3230 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3232 unsigned long save_flags;
3235 cache_alloc_debugcheck_before(cachep, flags);
3236 local_irq_save(save_flags);
3238 if (nodeid == -1 || nodeid == numa_node_id() ||
3239 !cachep->nodelists[nodeid])
3240 ptr = ____cache_alloc(cachep, flags);
3242 ptr = __cache_alloc_node(cachep, flags, nodeid);
3243 local_irq_restore(save_flags);
3245 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr,
3246 __builtin_return_address(0));
3250 EXPORT_SYMBOL(kmem_cache_alloc_node);
3252 void *kmalloc_node(size_t size, gfp_t flags, int node)
3254 struct kmem_cache *cachep;
3256 cachep = kmem_find_general_cachep(size, flags);
3257 if (unlikely(cachep == NULL))
3259 return kmem_cache_alloc_node(cachep, flags, node);
3261 EXPORT_SYMBOL(kmalloc_node);
3265 * kmalloc - allocate memory
3266 * @size: how many bytes of memory are required.
3267 * @flags: the type of memory to allocate.
3268 * @caller: function caller for debug tracking of the caller
3270 * kmalloc is the normal method of allocating memory
3273 * The @flags argument may be one of:
3275 * %GFP_USER - Allocate memory on behalf of user. May sleep.
3277 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
3279 * %GFP_ATOMIC - Allocation will not sleep. Use inside interrupt handlers.
3281 * Additionally, the %GFP_DMA flag may be set to indicate the memory
3282 * must be suitable for DMA. This can mean different things on different
3283 * platforms. For example, on i386, it means that the memory must come
3284 * from the first 16MB.
3286 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3289 struct kmem_cache *cachep;
3291 /* If you want to save a few bytes .text space: replace
3293 * Then kmalloc uses the uninlined functions instead of the inline
3296 cachep = __find_general_cachep(size, flags);
3297 if (unlikely(cachep == NULL))
3299 return __cache_alloc(cachep, flags, caller);
3303 void *__kmalloc(size_t size, gfp_t flags)
3305 #ifndef CONFIG_DEBUG_SLAB
3306 return __do_kmalloc(size, flags, NULL);
3308 return __do_kmalloc(size, flags, __builtin_return_address(0));
3311 EXPORT_SYMBOL(__kmalloc);
3313 #ifdef CONFIG_DEBUG_SLAB
3314 void *__kmalloc_track_caller(size_t size, gfp_t flags, void *caller)
3316 return __do_kmalloc(size, flags, caller);
3318 EXPORT_SYMBOL(__kmalloc_track_caller);
3323 * __alloc_percpu - allocate one copy of the object for every present
3324 * cpu in the system, zeroing them.
3325 * Objects should be dereferenced using the per_cpu_ptr macro only.
3327 * @size: how many bytes of memory are required.
3329 void *__alloc_percpu(size_t size)
3332 struct percpu_data *pdata = kmalloc(sizeof(*pdata), GFP_KERNEL);
3338 * Cannot use for_each_online_cpu since a cpu may come online
3339 * and we have no way of figuring out how to fix the array
3340 * that we have allocated then....
3342 for_each_possible_cpu(i) {
3343 int node = cpu_to_node(i);
3345 if (node_online(node))
3346 pdata->ptrs[i] = kmalloc_node(size, GFP_KERNEL, node);
3348 pdata->ptrs[i] = kmalloc(size, GFP_KERNEL);
3350 if (!pdata->ptrs[i])
3352 memset(pdata->ptrs[i], 0, size);
3355 /* Catch derefs w/o wrappers */
3356 return (void *)(~(unsigned long)pdata);
3360 if (!cpu_possible(i))
3362 kfree(pdata->ptrs[i]);
3367 EXPORT_SYMBOL(__alloc_percpu);
3371 * kmem_cache_free - Deallocate an object
3372 * @cachep: The cache the allocation was from.
3373 * @objp: The previously allocated object.
3375 * Free an object which was previously allocated from this
3378 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3380 unsigned long flags;
3382 local_irq_save(flags);
3383 __cache_free(cachep, objp);
3384 local_irq_restore(flags);
3386 EXPORT_SYMBOL(kmem_cache_free);
3389 * kfree - free previously allocated memory
3390 * @objp: pointer returned by kmalloc.
3392 * If @objp is NULL, no operation is performed.
3394 * Don't free memory not originally allocated by kmalloc()
3395 * or you will run into trouble.
3397 void kfree(const void *objp)
3399 struct kmem_cache *c;
3400 unsigned long flags;
3402 if (unlikely(!objp))
3404 local_irq_save(flags);
3405 kfree_debugcheck(objp);
3406 c = virt_to_cache(objp);
3407 mutex_debug_check_no_locks_freed(objp, obj_size(c));
3408 __cache_free(c, (void *)objp);
3409 local_irq_restore(flags);
3411 EXPORT_SYMBOL(kfree);
3415 * free_percpu - free previously allocated percpu memory
3416 * @objp: pointer returned by alloc_percpu.
3418 * Don't free memory not originally allocated by alloc_percpu()
3419 * The complemented objp is to check for that.
3421 void free_percpu(const void *objp)
3424 struct percpu_data *p = (struct percpu_data *)(~(unsigned long)objp);
3427 * We allocate for all cpus so we cannot use for online cpu here.
3429 for_each_possible_cpu(i)
3433 EXPORT_SYMBOL(free_percpu);
3436 unsigned int kmem_cache_size(struct kmem_cache *cachep)
3438 return obj_size(cachep);
3440 EXPORT_SYMBOL(kmem_cache_size);
3442 const char *kmem_cache_name(struct kmem_cache *cachep)
3444 return cachep->name;
3446 EXPORT_SYMBOL_GPL(kmem_cache_name);
3449 * This initializes kmem_list3 or resizes varioius caches for all nodes.
3451 static int alloc_kmemlist(struct kmem_cache *cachep)
3454 struct kmem_list3 *l3;
3455 struct array_cache *new_shared;
3456 struct array_cache **new_alien;
3458 for_each_online_node(node) {
3460 new_alien = alloc_alien_cache(node, cachep->limit);
3464 new_shared = alloc_arraycache(node,
3465 cachep->shared*cachep->batchcount,
3468 free_alien_cache(new_alien);
3472 l3 = cachep->nodelists[node];
3474 struct array_cache *shared = l3->shared;
3476 spin_lock_irq(&l3->list_lock);
3479 free_block(cachep, shared->entry,
3480 shared->avail, node);
3482 l3->shared = new_shared;
3484 l3->alien = new_alien;
3487 l3->free_limit = (1 + nr_cpus_node(node)) *
3488 cachep->batchcount + cachep->num;
3489 spin_unlock_irq(&l3->list_lock);
3491 free_alien_cache(new_alien);
3494 l3 = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, node);
3496 free_alien_cache(new_alien);
3501 kmem_list3_init(l3);
3502 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
3503 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
3504 l3->shared = new_shared;
3505 l3->alien = new_alien;
3506 l3->free_limit = (1 + nr_cpus_node(node)) *
3507 cachep->batchcount + cachep->num;
3508 cachep->nodelists[node] = l3;
3513 if (!cachep->next.next) {
3514 /* Cache is not active yet. Roll back what we did */
3517 if (cachep->nodelists[node]) {
3518 l3 = cachep->nodelists[node];
3521 free_alien_cache(l3->alien);
3523 cachep->nodelists[node] = NULL;
3531 struct ccupdate_struct {
3532 struct kmem_cache *cachep;
3533 struct array_cache *new[NR_CPUS];
3536 static void do_ccupdate_local(void *info)
3538 struct ccupdate_struct *new = info;
3539 struct array_cache *old;
3542 old = cpu_cache_get(new->cachep);
3544 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
3545 new->new[smp_processor_id()] = old;
3548 /* Always called with the cache_chain_mutex held */
3549 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3550 int batchcount, int shared)
3552 struct ccupdate_struct new;
3555 memset(&new.new, 0, sizeof(new.new));
3556 for_each_online_cpu(i) {
3557 new.new[i] = alloc_arraycache(cpu_to_node(i), limit,
3560 for (i--; i >= 0; i--)
3565 new.cachep = cachep;
3567 on_each_cpu(do_ccupdate_local, (void *)&new, 1, 1);
3570 cachep->batchcount = batchcount;
3571 cachep->limit = limit;
3572 cachep->shared = shared;
3574 for_each_online_cpu(i) {
3575 struct array_cache *ccold = new.new[i];
3578 spin_lock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3579 free_block(cachep, ccold->entry, ccold->avail, cpu_to_node(i));
3580 spin_unlock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3584 err = alloc_kmemlist(cachep);
3586 printk(KERN_ERR "alloc_kmemlist failed for %s, error %d.\n",
3587 cachep->name, -err);
3593 /* Called with cache_chain_mutex held always */
3594 static void enable_cpucache(struct kmem_cache *cachep)
3600 * The head array serves three purposes:
3601 * - create a LIFO ordering, i.e. return objects that are cache-warm
3602 * - reduce the number of spinlock operations.
3603 * - reduce the number of linked list operations on the slab and
3604 * bufctl chains: array operations are cheaper.
3605 * The numbers are guessed, we should auto-tune as described by
3608 if (cachep->buffer_size > 131072)
3610 else if (cachep->buffer_size > PAGE_SIZE)
3612 else if (cachep->buffer_size > 1024)
3614 else if (cachep->buffer_size > 256)
3620 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3621 * allocation behaviour: Most allocs on one cpu, most free operations
3622 * on another cpu. For these cases, an efficient object passing between
3623 * cpus is necessary. This is provided by a shared array. The array
3624 * replaces Bonwick's magazine layer.
3625 * On uniprocessor, it's functionally equivalent (but less efficient)
3626 * to a larger limit. Thus disabled by default.
3630 if (cachep->buffer_size <= PAGE_SIZE)
3636 * With debugging enabled, large batchcount lead to excessively long
3637 * periods with disabled local interrupts. Limit the batchcount
3642 err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared);
3644 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
3645 cachep->name, -err);
3649 * Drain an array if it contains any elements taking the l3 lock only if
3650 * necessary. Note that the l3 listlock also protects the array_cache
3651 * if drain_array() is used on the shared array.
3653 void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
3654 struct array_cache *ac, int force, int node)
3658 if (!ac || !ac->avail)
3660 if (ac->touched && !force) {
3663 spin_lock_irq(&l3->list_lock);
3665 tofree = force ? ac->avail : (ac->limit + 4) / 5;
3666 if (tofree > ac->avail)
3667 tofree = (ac->avail + 1) / 2;
3668 free_block(cachep, ac->entry, tofree, node);
3669 ac->avail -= tofree;
3670 memmove(ac->entry, &(ac->entry[tofree]),
3671 sizeof(void *) * ac->avail);
3673 spin_unlock_irq(&l3->list_lock);
3678 * cache_reap - Reclaim memory from caches.
3679 * @unused: unused parameter
3681 * Called from workqueue/eventd every few seconds.
3683 * - clear the per-cpu caches for this CPU.
3684 * - return freeable pages to the main free memory pool.
3686 * If we cannot acquire the cache chain mutex then just give up - we'll try
3687 * again on the next iteration.
3689 static void cache_reap(void *unused)
3691 struct kmem_cache *searchp;
3692 struct kmem_list3 *l3;
3693 int node = numa_node_id();
3695 if (!mutex_trylock(&cache_chain_mutex)) {
3696 /* Give up. Setup the next iteration. */
3697 schedule_delayed_work(&__get_cpu_var(reap_work),
3702 list_for_each_entry(searchp, &cache_chain, next) {
3703 struct list_head *p;
3710 * We only take the l3 lock if absolutely necessary and we
3711 * have established with reasonable certainty that
3712 * we can do some work if the lock was obtained.
3714 l3 = searchp->nodelists[node];
3716 reap_alien(searchp, l3);
3718 drain_array(searchp, l3, cpu_cache_get(searchp), 0, node);
3721 * These are racy checks but it does not matter
3722 * if we skip one check or scan twice.
3724 if (time_after(l3->next_reap, jiffies))
3727 l3->next_reap = jiffies + REAPTIMEOUT_LIST3;
3729 drain_array(searchp, l3, l3->shared, 0, node);
3731 if (l3->free_touched) {
3732 l3->free_touched = 0;
3736 tofree = (l3->free_limit + 5 * searchp->num - 1) /
3740 * Do not lock if there are no free blocks.
3742 if (list_empty(&l3->slabs_free))
3745 spin_lock_irq(&l3->list_lock);
3746 p = l3->slabs_free.next;
3747 if (p == &(l3->slabs_free)) {
3748 spin_unlock_irq(&l3->list_lock);
3752 slabp = list_entry(p, struct slab, list);
3753 BUG_ON(slabp->inuse);
3754 list_del(&slabp->list);
3755 STATS_INC_REAPED(searchp);
3758 * Safe to drop the lock. The slab is no longer linked
3759 * to the cache. searchp cannot disappear, we hold
3762 l3->free_objects -= searchp->num;
3763 spin_unlock_irq(&l3->list_lock);
3764 slab_destroy(searchp, slabp);
3765 } while (--tofree > 0);
3770 mutex_unlock(&cache_chain_mutex);
3772 /* Set up the next iteration */
3773 schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC);
3776 #ifdef CONFIG_PROC_FS
3778 static void print_slabinfo_header(struct seq_file *m)
3781 * Output format version, so at least we can change it
3782 * without _too_ many complaints.
3785 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
3787 seq_puts(m, "slabinfo - version: 2.1\n");
3789 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
3790 "<objperslab> <pagesperslab>");
3791 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
3792 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
3794 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
3795 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
3796 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
3801 static void *s_start(struct seq_file *m, loff_t *pos)
3804 struct list_head *p;
3806 mutex_lock(&cache_chain_mutex);
3808 print_slabinfo_header(m);
3809 p = cache_chain.next;
3812 if (p == &cache_chain)
3815 return list_entry(p, struct kmem_cache, next);
3818 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
3820 struct kmem_cache *cachep = p;
3822 return cachep->next.next == &cache_chain ?
3823 NULL : list_entry(cachep->next.next, struct kmem_cache, next);
3826 static void s_stop(struct seq_file *m, void *p)
3828 mutex_unlock(&cache_chain_mutex);
3831 static int s_show(struct seq_file *m, void *p)
3833 struct kmem_cache *cachep = p;
3835 unsigned long active_objs;
3836 unsigned long num_objs;
3837 unsigned long active_slabs = 0;
3838 unsigned long num_slabs, free_objects = 0, shared_avail = 0;
3842 struct kmem_list3 *l3;
3846 for_each_online_node(node) {
3847 l3 = cachep->nodelists[node];
3852 spin_lock_irq(&l3->list_lock);
3854 list_for_each_entry(slabp, &l3->slabs_full, list) {
3855 if (slabp->inuse != cachep->num && !error)
3856 error = "slabs_full accounting error";
3857 active_objs += cachep->num;
3860 list_for_each_entry(slabp, &l3->slabs_partial, list) {
3861 if (slabp->inuse == cachep->num && !error)
3862 error = "slabs_partial inuse accounting error";
3863 if (!slabp->inuse && !error)
3864 error = "slabs_partial/inuse accounting error";
3865 active_objs += slabp->inuse;
3868 list_for_each_entry(slabp, &l3->slabs_free, list) {
3869 if (slabp->inuse && !error)
3870 error = "slabs_free/inuse accounting error";
3873 free_objects += l3->free_objects;
3875 shared_avail += l3->shared->avail;
3877 spin_unlock_irq(&l3->list_lock);
3879 num_slabs += active_slabs;
3880 num_objs = num_slabs * cachep->num;
3881 if (num_objs - active_objs != free_objects && !error)
3882 error = "free_objects accounting error";
3884 name = cachep->name;
3886 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
3888 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
3889 name, active_objs, num_objs, cachep->buffer_size,
3890 cachep->num, (1 << cachep->gfporder));
3891 seq_printf(m, " : tunables %4u %4u %4u",
3892 cachep->limit, cachep->batchcount, cachep->shared);
3893 seq_printf(m, " : slabdata %6lu %6lu %6lu",
3894 active_slabs, num_slabs, shared_avail);
3897 unsigned long high = cachep->high_mark;
3898 unsigned long allocs = cachep->num_allocations;
3899 unsigned long grown = cachep->grown;
3900 unsigned long reaped = cachep->reaped;
3901 unsigned long errors = cachep->errors;
3902 unsigned long max_freeable = cachep->max_freeable;
3903 unsigned long node_allocs = cachep->node_allocs;
3904 unsigned long node_frees = cachep->node_frees;
3905 unsigned long overflows = cachep->node_overflow;
3907 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu \
3908 %4lu %4lu %4lu %4lu %4lu", allocs, high, grown,
3909 reaped, errors, max_freeable, node_allocs,
3910 node_frees, overflows);
3914 unsigned long allochit = atomic_read(&cachep->allochit);
3915 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
3916 unsigned long freehit = atomic_read(&cachep->freehit);
3917 unsigned long freemiss = atomic_read(&cachep->freemiss);
3919 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
3920 allochit, allocmiss, freehit, freemiss);
3928 * slabinfo_op - iterator that generates /proc/slabinfo
3937 * num-pages-per-slab
3938 * + further values on SMP and with statistics enabled
3941 struct seq_operations slabinfo_op = {
3948 #define MAX_SLABINFO_WRITE 128
3950 * slabinfo_write - Tuning for the slab allocator
3952 * @buffer: user buffer
3953 * @count: data length
3956 ssize_t slabinfo_write(struct file *file, const char __user * buffer,
3957 size_t count, loff_t *ppos)
3959 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
3960 int limit, batchcount, shared, res;
3961 struct kmem_cache *cachep;
3963 if (count > MAX_SLABINFO_WRITE)
3965 if (copy_from_user(&kbuf, buffer, count))
3967 kbuf[MAX_SLABINFO_WRITE] = '\0';
3969 tmp = strchr(kbuf, ' ');
3974 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
3977 /* Find the cache in the chain of caches. */
3978 mutex_lock(&cache_chain_mutex);
3980 list_for_each_entry(cachep, &cache_chain, next) {
3981 if (!strcmp(cachep->name, kbuf)) {
3982 if (limit < 1 || batchcount < 1 ||
3983 batchcount > limit || shared < 0) {
3986 res = do_tune_cpucache(cachep, limit,
3987 batchcount, shared);
3992 mutex_unlock(&cache_chain_mutex);
3998 #ifdef CONFIG_DEBUG_SLAB_LEAK
4000 static void *leaks_start(struct seq_file *m, loff_t *pos)
4003 struct list_head *p;
4005 mutex_lock(&cache_chain_mutex);
4006 p = cache_chain.next;
4009 if (p == &cache_chain)
4012 return list_entry(p, struct kmem_cache, next);
4015 static inline int add_caller(unsigned long *n, unsigned long v)
4025 unsigned long *q = p + 2 * i;
4039 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4045 static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
4051 for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) {
4052 if (slab_bufctl(s)[i] != BUFCTL_ACTIVE)
4054 if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4059 static void show_symbol(struct seq_file *m, unsigned long address)
4061 #ifdef CONFIG_KALLSYMS
4064 unsigned long offset, size;
4065 char namebuf[KSYM_NAME_LEN+1];
4067 name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
4070 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4072 seq_printf(m, " [%s]", modname);
4076 seq_printf(m, "%p", (void *)address);
4079 static int leaks_show(struct seq_file *m, void *p)
4081 struct kmem_cache *cachep = p;
4083 struct kmem_list3 *l3;
4085 unsigned long *n = m->private;
4089 if (!(cachep->flags & SLAB_STORE_USER))
4091 if (!(cachep->flags & SLAB_RED_ZONE))
4094 /* OK, we can do it */
4098 for_each_online_node(node) {
4099 l3 = cachep->nodelists[node];
4104 spin_lock_irq(&l3->list_lock);
4106 list_for_each_entry(slabp, &l3->slabs_full, list)
4107 handle_slab(n, cachep, slabp);
4108 list_for_each_entry(slabp, &l3->slabs_partial, list)
4109 handle_slab(n, cachep, slabp);
4110 spin_unlock_irq(&l3->list_lock);
4112 name = cachep->name;
4114 /* Increase the buffer size */
4115 mutex_unlock(&cache_chain_mutex);
4116 m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4118 /* Too bad, we are really out */
4120 mutex_lock(&cache_chain_mutex);
4123 *(unsigned long *)m->private = n[0] * 2;
4125 mutex_lock(&cache_chain_mutex);
4126 /* Now make sure this entry will be retried */
4130 for (i = 0; i < n[1]; i++) {
4131 seq_printf(m, "%s: %lu ", name, n[2*i+3]);
4132 show_symbol(m, n[2*i+2]);
4138 struct seq_operations slabstats_op = {
4139 .start = leaks_start,
4148 * ksize - get the actual amount of memory allocated for a given object
4149 * @objp: Pointer to the object
4151 * kmalloc may internally round up allocations and return more memory
4152 * than requested. ksize() can be used to determine the actual amount of
4153 * memory allocated. The caller may use this additional memory, even though
4154 * a smaller amount of memory was initially specified with the kmalloc call.
4155 * The caller must guarantee that objp points to a valid object previously
4156 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4157 * must not be freed during the duration of the call.
4159 unsigned int ksize(const void *objp)
4161 if (unlikely(objp == NULL))
4164 return obj_size(virt_to_cache(objp));