3 * Written by Mark Hemment, 1996/97.
4 * (markhe@nextd.demon.co.uk)
6 * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
8 * Major cleanup, different bufctl logic, per-cpu arrays
9 * (c) 2000 Manfred Spraul
11 * Cleanup, make the head arrays unconditional, preparation for NUMA
12 * (c) 2002 Manfred Spraul
14 * An implementation of the Slab Allocator as described in outline in;
15 * UNIX Internals: The New Frontiers by Uresh Vahalia
16 * Pub: Prentice Hall ISBN 0-13-101908-2
17 * or with a little more detail in;
18 * The Slab Allocator: An Object-Caching Kernel Memory Allocator
19 * Jeff Bonwick (Sun Microsystems).
20 * Presented at: USENIX Summer 1994 Technical Conference
22 * The memory is organized in caches, one cache for each object type.
23 * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
24 * Each cache consists out of many slabs (they are small (usually one
25 * page long) and always contiguous), and each slab contains multiple
26 * initialized objects.
28 * This means, that your constructor is used only for newly allocated
29 * slabs and you must pass objects with the same intializations to
32 * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM,
33 * normal). If you need a special memory type, then must create a new
34 * cache for that memory type.
36 * In order to reduce fragmentation, the slabs are sorted in 3 groups:
37 * full slabs with 0 free objects
39 * empty slabs with no allocated objects
41 * If partial slabs exist, then new allocations come from these slabs,
42 * otherwise from empty slabs or new slabs are allocated.
44 * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache
45 * during kmem_cache_destroy(). The caller must prevent concurrent allocs.
47 * Each cache has a short per-cpu head array, most allocs
48 * and frees go into that array, and if that array overflows, then 1/2
49 * of the entries in the array are given back into the global cache.
50 * The head array is strictly LIFO and should improve the cache hit rates.
51 * On SMP, it additionally reduces the spinlock operations.
53 * The c_cpuarray may not be read with enabled local interrupts -
54 * it's changed with a smp_call_function().
56 * SMP synchronization:
57 * constructors and destructors are called without any locking.
58 * Several members in struct kmem_cache and struct slab never change, they
59 * are accessed without any locking.
60 * The per-cpu arrays are never accessed from the wrong cpu, no locking,
61 * and local interrupts are disabled so slab code is preempt-safe.
62 * The non-constant members are protected with a per-cache irq spinlock.
64 * Many thanks to Mark Hemment, who wrote another per-cpu slab patch
65 * in 2000 - many ideas in the current implementation are derived from
68 * Further notes from the original documentation:
70 * 11 April '97. Started multi-threading - markhe
71 * The global cache-chain is protected by the mutex 'cache_chain_mutex'.
72 * The sem is only needed when accessing/extending the cache-chain, which
73 * can never happen inside an interrupt (kmem_cache_create(),
74 * kmem_cache_shrink() and kmem_cache_reap()).
76 * At present, each engine can be growing a cache. This should be blocked.
78 * 15 March 2005. NUMA slab allocator.
79 * Shai Fultheim <shai@scalex86.org>.
80 * Shobhit Dayal <shobhit@calsoftinc.com>
81 * Alok N Kataria <alokk@calsoftinc.com>
82 * Christoph Lameter <christoph@lameter.com>
84 * Modified the slab allocator to be node aware on NUMA systems.
85 * Each node has its own list of partial, free and full slabs.
86 * All object allocations for a node occur from node specific slab lists.
89 #include <linux/config.h>
90 #include <linux/slab.h>
92 #include <linux/swap.h>
93 #include <linux/cache.h>
94 #include <linux/interrupt.h>
95 #include <linux/init.h>
96 #include <linux/compiler.h>
97 #include <linux/seq_file.h>
98 #include <linux/notifier.h>
99 #include <linux/kallsyms.h>
100 #include <linux/cpu.h>
101 #include <linux/sysctl.h>
102 #include <linux/module.h>
103 #include <linux/rcupdate.h>
104 #include <linux/string.h>
105 #include <linux/nodemask.h>
106 #include <linux/mempolicy.h>
107 #include <linux/mutex.h>
109 #include <asm/uaccess.h>
110 #include <asm/cacheflush.h>
111 #include <asm/tlbflush.h>
112 #include <asm/page.h>
115 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
116 * SLAB_RED_ZONE & SLAB_POISON.
117 * 0 for faster, smaller code (especially in the critical paths).
119 * STATS - 1 to collect stats for /proc/slabinfo.
120 * 0 for faster, smaller code (especially in the critical paths).
122 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
125 #ifdef CONFIG_DEBUG_SLAB
128 #define FORCED_DEBUG 1
132 #define FORCED_DEBUG 0
135 /* Shouldn't this be in a header file somewhere? */
136 #define BYTES_PER_WORD sizeof(void *)
138 #ifndef cache_line_size
139 #define cache_line_size() L1_CACHE_BYTES
142 #ifndef ARCH_KMALLOC_MINALIGN
144 * Enforce a minimum alignment for the kmalloc caches.
145 * Usually, the kmalloc caches are cache_line_size() aligned, except when
146 * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
147 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
148 * alignment larger than BYTES_PER_WORD. ARCH_KMALLOC_MINALIGN allows that.
149 * Note that this flag disables some debug features.
151 #define ARCH_KMALLOC_MINALIGN 0
154 #ifndef ARCH_SLAB_MINALIGN
156 * Enforce a minimum alignment for all caches.
157 * Intended for archs that get misalignment faults even for BYTES_PER_WORD
158 * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
159 * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
160 * some debug features.
162 #define ARCH_SLAB_MINALIGN 0
165 #ifndef ARCH_KMALLOC_FLAGS
166 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
169 /* Legal flag mask for kmem_cache_create(). */
171 # define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
172 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
173 SLAB_NO_REAP | SLAB_CACHE_DMA | \
174 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \
175 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
178 # define CREATE_MASK (SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \
179 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \
180 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
187 * Bufctl's are used for linking objs within a slab
190 * This implementation relies on "struct page" for locating the cache &
191 * slab an object belongs to.
192 * This allows the bufctl structure to be small (one int), but limits
193 * the number of objects a slab (not a cache) can contain when off-slab
194 * bufctls are used. The limit is the size of the largest general cache
195 * that does not use off-slab slabs.
196 * For 32bit archs with 4 kB pages, is this 56.
197 * This is not serious, as it is only for large objects, when it is unwise
198 * to have too many per slab.
199 * Note: This limit can be raised by introducing a general cache whose size
200 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
203 typedef unsigned int kmem_bufctl_t;
204 #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
205 #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
206 #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-2)
208 /* Max number of objs-per-slab for caches which use off-slab slabs.
209 * Needed to avoid a possible looping condition in cache_grow().
211 static unsigned long offslab_limit;
216 * Manages the objs in a slab. Placed either at the beginning of mem allocated
217 * for a slab, or allocated from an general cache.
218 * Slabs are chained into three list: fully used, partial, fully free slabs.
221 struct list_head list;
222 unsigned long colouroff;
223 void *s_mem; /* including colour offset */
224 unsigned int inuse; /* num of objs active in slab */
226 unsigned short nodeid;
232 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
233 * arrange for kmem_freepages to be called via RCU. This is useful if
234 * we need to approach a kernel structure obliquely, from its address
235 * obtained without the usual locking. We can lock the structure to
236 * stabilize it and check it's still at the given address, only if we
237 * can be sure that the memory has not been meanwhile reused for some
238 * other kind of object (which our subsystem's lock might corrupt).
240 * rcu_read_lock before reading the address, then rcu_read_unlock after
241 * taking the spinlock within the structure expected at that address.
243 * We assume struct slab_rcu can overlay struct slab when destroying.
246 struct rcu_head head;
247 struct kmem_cache *cachep;
255 * - LIFO ordering, to hand out cache-warm objects from _alloc
256 * - reduce the number of linked list operations
257 * - reduce spinlock operations
259 * The limit is stored in the per-cpu structure to reduce the data cache
266 unsigned int batchcount;
267 unsigned int touched;
270 * Must have this definition in here for the proper
271 * alignment of array_cache. Also simplifies accessing
273 * [0] is for gcc 2.95. It should really be [].
278 * bootstrap: The caches do not work without cpuarrays anymore, but the
279 * cpuarrays are allocated from the generic caches...
281 #define BOOT_CPUCACHE_ENTRIES 1
282 struct arraycache_init {
283 struct array_cache cache;
284 void *entries[BOOT_CPUCACHE_ENTRIES];
288 * The slab lists for all objects.
291 struct list_head slabs_partial; /* partial list first, better asm code */
292 struct list_head slabs_full;
293 struct list_head slabs_free;
294 unsigned long free_objects;
295 unsigned long next_reap;
297 unsigned int free_limit;
298 unsigned int colour_next; /* Per-node cache coloring */
299 spinlock_t list_lock;
300 struct array_cache *shared; /* shared per node */
301 struct array_cache **alien; /* on other nodes */
305 * Need this for bootstrapping a per node allocator.
307 #define NUM_INIT_LISTS (2 * MAX_NUMNODES + 1)
308 struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
309 #define CACHE_CACHE 0
311 #define SIZE_L3 (1 + MAX_NUMNODES)
314 * This function must be completely optimized away if a constant is passed to
315 * it. Mostly the same as what is in linux/slab.h except it returns an index.
317 static __always_inline int index_of(const size_t size)
319 extern void __bad_size(void);
321 if (__builtin_constant_p(size)) {
329 #include "linux/kmalloc_sizes.h"
337 #define INDEX_AC index_of(sizeof(struct arraycache_init))
338 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
340 static void kmem_list3_init(struct kmem_list3 *parent)
342 INIT_LIST_HEAD(&parent->slabs_full);
343 INIT_LIST_HEAD(&parent->slabs_partial);
344 INIT_LIST_HEAD(&parent->slabs_free);
345 parent->shared = NULL;
346 parent->alien = NULL;
347 parent->colour_next = 0;
348 spin_lock_init(&parent->list_lock);
349 parent->free_objects = 0;
350 parent->free_touched = 0;
353 #define MAKE_LIST(cachep, listp, slab, nodeid) \
355 INIT_LIST_HEAD(listp); \
356 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
359 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
361 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
362 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
363 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
373 /* 1) per-cpu data, touched during every alloc/free */
374 struct array_cache *array[NR_CPUS];
375 unsigned int batchcount;
378 unsigned int buffer_size;
379 /* 2) touched by every alloc & free from the backend */
380 struct kmem_list3 *nodelists[MAX_NUMNODES];
381 unsigned int flags; /* constant flags */
382 unsigned int num; /* # of objs per slab */
385 /* 3) cache_grow/shrink */
386 /* order of pgs per slab (2^n) */
387 unsigned int gfporder;
389 /* force GFP flags, e.g. GFP_DMA */
392 size_t colour; /* cache colouring range */
393 unsigned int colour_off; /* colour offset */
394 struct kmem_cache *slabp_cache;
395 unsigned int slab_size;
396 unsigned int dflags; /* dynamic flags */
398 /* constructor func */
399 void (*ctor) (void *, struct kmem_cache *, unsigned long);
401 /* de-constructor func */
402 void (*dtor) (void *, struct kmem_cache *, unsigned long);
404 /* 4) cache creation/removal */
406 struct list_head next;
410 unsigned long num_active;
411 unsigned long num_allocations;
412 unsigned long high_mark;
414 unsigned long reaped;
415 unsigned long errors;
416 unsigned long max_freeable;
417 unsigned long node_allocs;
418 unsigned long node_frees;
426 * If debugging is enabled, then the allocator can add additional
427 * fields and/or padding to every object. buffer_size contains the total
428 * object size including these internal fields, the following two
429 * variables contain the offset to the user object and its size.
436 #define CFLGS_OFF_SLAB (0x80000000UL)
437 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
439 #define BATCHREFILL_LIMIT 16
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_SET_FREEABLE(x, i) \
466 if ((x)->max_freeable < i) \
467 (x)->max_freeable = i; \
469 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
470 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
471 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
472 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
474 #define STATS_INC_ACTIVE(x) do { } while (0)
475 #define STATS_DEC_ACTIVE(x) do { } while (0)
476 #define STATS_INC_ALLOCED(x) do { } while (0)
477 #define STATS_INC_GROWN(x) do { } while (0)
478 #define STATS_INC_REAPED(x) do { } while (0)
479 #define STATS_SET_HIGH(x) do { } while (0)
480 #define STATS_INC_ERR(x) do { } while (0)
481 #define STATS_INC_NODEALLOCS(x) do { } while (0)
482 #define STATS_INC_NODEFREES(x) do { } while (0)
483 #define STATS_SET_FREEABLE(x, i) do { } while (0)
484 #define STATS_INC_ALLOCHIT(x) do { } while (0)
485 #define STATS_INC_ALLOCMISS(x) do { } while (0)
486 #define STATS_INC_FREEHIT(x) do { } while (0)
487 #define STATS_INC_FREEMISS(x) do { } while (0)
492 * Magic nums for obj red zoning.
493 * Placed in the first word before and the first word after an obj.
495 #define RED_INACTIVE 0x5A2CF071UL /* when obj is inactive */
496 #define RED_ACTIVE 0x170FC2A5UL /* when obj is active */
498 /* ...and for poisoning */
499 #define POISON_INUSE 0x5a /* for use-uninitialised poisoning */
500 #define POISON_FREE 0x6b /* for use-after-free poisoning */
501 #define POISON_END 0xa5 /* end-byte of poisoning */
504 * memory layout of objects:
506 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
507 * the end of an object is aligned with the end of the real
508 * allocation. Catches writes behind the end of the allocation.
509 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
511 * cachep->obj_offset: The real object.
512 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
513 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
514 * [BYTES_PER_WORD long]
516 static int obj_offset(struct kmem_cache *cachep)
518 return cachep->obj_offset;
521 static int obj_size(struct kmem_cache *cachep)
523 return cachep->obj_size;
526 static unsigned long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
528 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
529 return (unsigned long*) (objp+obj_offset(cachep)-BYTES_PER_WORD);
532 static unsigned long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
534 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
535 if (cachep->flags & SLAB_STORE_USER)
536 return (unsigned long *)(objp + cachep->buffer_size -
538 return (unsigned long *)(objp + cachep->buffer_size - BYTES_PER_WORD);
541 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
543 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
544 return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
549 #define obj_offset(x) 0
550 #define obj_size(cachep) (cachep->buffer_size)
551 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long *)NULL;})
552 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long *)NULL;})
553 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
558 * Maximum size of an obj (in 2^order pages) and absolute limit for the gfp
561 #if defined(CONFIG_LARGE_ALLOCS)
562 #define MAX_OBJ_ORDER 13 /* up to 32Mb */
563 #define MAX_GFP_ORDER 13 /* up to 32Mb */
564 #elif defined(CONFIG_MMU)
565 #define MAX_OBJ_ORDER 5 /* 32 pages */
566 #define MAX_GFP_ORDER 5 /* 32 pages */
568 #define MAX_OBJ_ORDER 8 /* up to 1Mb */
569 #define MAX_GFP_ORDER 8 /* up to 1Mb */
573 * Do not go above this order unless 0 objects fit into the slab.
575 #define BREAK_GFP_ORDER_HI 1
576 #define BREAK_GFP_ORDER_LO 0
577 static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
580 * Functions for storing/retrieving the cachep and or slab from the page
581 * allocator. These are used to find the slab an obj belongs to. With kfree(),
582 * these are used to find the cache which an obj belongs to.
584 static inline void page_set_cache(struct page *page, struct kmem_cache *cache)
586 page->lru.next = (struct list_head *)cache;
589 static inline struct kmem_cache *page_get_cache(struct page *page)
591 return (struct kmem_cache *)page->lru.next;
594 static inline void page_set_slab(struct page *page, struct slab *slab)
596 page->lru.prev = (struct list_head *)slab;
599 static inline struct slab *page_get_slab(struct page *page)
601 return (struct slab *)page->lru.prev;
604 static inline struct kmem_cache *virt_to_cache(const void *obj)
606 struct page *page = virt_to_page(obj);
607 return page_get_cache(page);
610 static inline struct slab *virt_to_slab(const void *obj)
612 struct page *page = virt_to_page(obj);
613 return page_get_slab(page);
616 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
619 return slab->s_mem + cache->buffer_size * idx;
622 static inline unsigned int obj_to_index(struct kmem_cache *cache,
623 struct slab *slab, void *obj)
625 return (unsigned)(obj - slab->s_mem) / cache->buffer_size;
629 * These are the default caches for kmalloc. Custom caches can have other sizes.
631 struct cache_sizes malloc_sizes[] = {
632 #define CACHE(x) { .cs_size = (x) },
633 #include <linux/kmalloc_sizes.h>
637 EXPORT_SYMBOL(malloc_sizes);
639 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
645 static struct cache_names __initdata cache_names[] = {
646 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
647 #include <linux/kmalloc_sizes.h>
652 static struct arraycache_init initarray_cache __initdata =
653 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
654 static struct arraycache_init initarray_generic =
655 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
657 /* internal cache of cache description objs */
658 static struct kmem_cache cache_cache = {
660 .limit = BOOT_CPUCACHE_ENTRIES,
662 .buffer_size = sizeof(struct kmem_cache),
663 .flags = SLAB_NO_REAP,
664 .spinlock = SPIN_LOCK_UNLOCKED,
665 .name = "kmem_cache",
667 .obj_size = sizeof(struct kmem_cache),
671 /* Guard access to the cache-chain. */
672 static DEFINE_MUTEX(cache_chain_mutex);
673 static struct list_head cache_chain;
676 * vm_enough_memory() looks at this to determine how many slab-allocated pages
677 * are possibly freeable under pressure
679 * SLAB_RECLAIM_ACCOUNT turns this on per-slab
681 atomic_t slab_reclaim_pages;
684 * chicken and egg problem: delay the per-cpu array allocation
685 * until the general caches are up.
694 static DEFINE_PER_CPU(struct work_struct, reap_work);
696 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
698 static void enable_cpucache(struct kmem_cache *cachep);
699 static void cache_reap(void *unused);
700 static int __node_shrink(struct kmem_cache *cachep, int node);
702 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
704 return cachep->array[smp_processor_id()];
707 static inline struct kmem_cache *__find_general_cachep(size_t size,
710 struct cache_sizes *csizep = malloc_sizes;
713 /* This happens if someone tries to call
714 * kmem_cache_create(), or __kmalloc(), before
715 * the generic caches are initialized.
717 BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
719 while (size > csizep->cs_size)
723 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
724 * has cs_{dma,}cachep==NULL. Thus no special case
725 * for large kmalloc calls required.
727 if (unlikely(gfpflags & GFP_DMA))
728 return csizep->cs_dmacachep;
729 return csizep->cs_cachep;
732 struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
734 return __find_general_cachep(size, gfpflags);
736 EXPORT_SYMBOL(kmem_find_general_cachep);
738 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
740 return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
744 * Calculate the number of objects and left-over bytes for a given buffer size.
746 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
747 size_t align, int flags, size_t *left_over,
752 size_t slab_size = PAGE_SIZE << gfporder;
755 * The slab management structure can be either off the slab or
756 * on it. For the latter case, the memory allocated for a
760 * - One kmem_bufctl_t for each object
761 * - Padding to respect alignment of @align
762 * - @buffer_size bytes for each object
764 * If the slab management structure is off the slab, then the
765 * alignment will already be calculated into the size. Because
766 * the slabs are all pages aligned, the objects will be at the
767 * correct alignment when allocated.
769 if (flags & CFLGS_OFF_SLAB) {
771 nr_objs = slab_size / buffer_size;
773 if (nr_objs > SLAB_LIMIT)
774 nr_objs = SLAB_LIMIT;
777 * Ignore padding for the initial guess. The padding
778 * is at most @align-1 bytes, and @buffer_size is at
779 * least @align. In the worst case, this result will
780 * be one greater than the number of objects that fit
781 * into the memory allocation when taking the padding
784 nr_objs = (slab_size - sizeof(struct slab)) /
785 (buffer_size + sizeof(kmem_bufctl_t));
788 * This calculated number will be either the right
789 * amount, or one greater than what we want.
791 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
795 if (nr_objs > SLAB_LIMIT)
796 nr_objs = SLAB_LIMIT;
798 mgmt_size = slab_mgmt_size(nr_objs, align);
801 *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
804 #define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg)
806 static void __slab_error(const char *function, struct kmem_cache *cachep,
809 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
810 function, cachep->name, msg);
816 * Special reaping functions for NUMA systems called from cache_reap().
817 * These take care of doing round robin flushing of alien caches (containing
818 * objects freed on different nodes from which they were allocated) and the
819 * flushing of remote pcps by calling drain_node_pages.
821 static DEFINE_PER_CPU(unsigned long, reap_node);
823 static void init_reap_node(int cpu)
827 node = next_node(cpu_to_node(cpu), node_online_map);
828 if (node == MAX_NUMNODES)
831 __get_cpu_var(reap_node) = node;
834 static void next_reap_node(void)
836 int node = __get_cpu_var(reap_node);
839 * Also drain per cpu pages on remote zones
841 if (node != numa_node_id())
842 drain_node_pages(node);
844 node = next_node(node, node_online_map);
845 if (unlikely(node >= MAX_NUMNODES))
846 node = first_node(node_online_map);
847 __get_cpu_var(reap_node) = node;
851 #define init_reap_node(cpu) do { } while (0)
852 #define next_reap_node(void) do { } while (0)
856 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
857 * via the workqueue/eventd.
858 * Add the CPU number into the expiration time to minimize the possibility of
859 * the CPUs getting into lockstep and contending for the global cache chain
862 static void __devinit start_cpu_timer(int cpu)
864 struct work_struct *reap_work = &per_cpu(reap_work, cpu);
867 * When this gets called from do_initcalls via cpucache_init(),
868 * init_workqueues() has already run, so keventd will be setup
871 if (keventd_up() && reap_work->func == NULL) {
873 INIT_WORK(reap_work, cache_reap, NULL);
874 schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu);
878 static struct array_cache *alloc_arraycache(int node, int entries,
881 int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
882 struct array_cache *nc = NULL;
884 nc = kmalloc_node(memsize, GFP_KERNEL, node);
888 nc->batchcount = batchcount;
890 spin_lock_init(&nc->lock);
896 static void *__cache_alloc_node(struct kmem_cache *, gfp_t, int);
898 static struct array_cache **alloc_alien_cache(int node, int limit)
900 struct array_cache **ac_ptr;
901 int memsize = sizeof(void *) * MAX_NUMNODES;
906 ac_ptr = kmalloc_node(memsize, GFP_KERNEL, node);
909 if (i == node || !node_online(i)) {
913 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d);
915 for (i--; i <= 0; i--)
925 static void free_alien_cache(struct array_cache **ac_ptr)
936 static void __drain_alien_cache(struct kmem_cache *cachep,
937 struct array_cache *ac, int node)
939 struct kmem_list3 *rl3 = cachep->nodelists[node];
942 spin_lock(&rl3->list_lock);
943 free_block(cachep, ac->entry, ac->avail, node);
945 spin_unlock(&rl3->list_lock);
950 * Called from cache_reap() to regularly drain alien caches round robin.
952 static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
954 int node = __get_cpu_var(reap_node);
957 struct array_cache *ac = l3->alien[node];
958 if (ac && ac->avail) {
959 spin_lock_irq(&ac->lock);
960 __drain_alien_cache(cachep, ac, node);
961 spin_unlock_irq(&ac->lock);
966 static void drain_alien_cache(struct kmem_cache *cachep,
967 struct array_cache **alien)
970 struct array_cache *ac;
973 for_each_online_node(i) {
976 spin_lock_irqsave(&ac->lock, flags);
977 __drain_alien_cache(cachep, ac, i);
978 spin_unlock_irqrestore(&ac->lock, flags);
984 #define drain_alien_cache(cachep, alien) do { } while (0)
985 #define reap_alien(cachep, l3) do { } while (0)
987 static inline struct array_cache **alloc_alien_cache(int node, int limit)
989 return (struct array_cache **) 0x01020304ul;
992 static inline void free_alien_cache(struct array_cache **ac_ptr)
998 static int __devinit cpuup_callback(struct notifier_block *nfb,
999 unsigned long action, void *hcpu)
1001 long cpu = (long)hcpu;
1002 struct kmem_cache *cachep;
1003 struct kmem_list3 *l3 = NULL;
1004 int node = cpu_to_node(cpu);
1005 int memsize = sizeof(struct kmem_list3);
1008 case CPU_UP_PREPARE:
1009 mutex_lock(&cache_chain_mutex);
1011 * We need to do this right in the beginning since
1012 * alloc_arraycache's are going to use this list.
1013 * kmalloc_node allows us to add the slab to the right
1014 * kmem_list3 and not this cpu's kmem_list3
1017 list_for_each_entry(cachep, &cache_chain, next) {
1019 * Set up the size64 kmemlist for cpu before we can
1020 * begin anything. Make sure some other cpu on this
1021 * node has not already allocated this
1023 if (!cachep->nodelists[node]) {
1024 l3 = kmalloc_node(memsize, GFP_KERNEL, node);
1027 kmem_list3_init(l3);
1028 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1029 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1032 * The l3s don't come and go as CPUs come and
1033 * go. cache_chain_mutex is sufficient
1036 cachep->nodelists[node] = l3;
1039 spin_lock_irq(&cachep->nodelists[node]->list_lock);
1040 cachep->nodelists[node]->free_limit =
1041 (1 + nr_cpus_node(node)) *
1042 cachep->batchcount + cachep->num;
1043 spin_unlock_irq(&cachep->nodelists[node]->list_lock);
1047 * Now we can go ahead with allocating the shared arrays and
1050 list_for_each_entry(cachep, &cache_chain, next) {
1051 struct array_cache *nc;
1052 struct array_cache *shared;
1053 struct array_cache **alien;
1055 nc = alloc_arraycache(node, cachep->limit,
1056 cachep->batchcount);
1059 shared = alloc_arraycache(node,
1060 cachep->shared * cachep->batchcount,
1065 alien = alloc_alien_cache(node, cachep->limit);
1068 cachep->array[cpu] = nc;
1069 l3 = cachep->nodelists[node];
1072 spin_lock_irq(&l3->list_lock);
1075 * We are serialised from CPU_DEAD or
1076 * CPU_UP_CANCELLED by the cpucontrol lock
1078 l3->shared = shared;
1087 spin_unlock_irq(&l3->list_lock);
1089 free_alien_cache(alien);
1091 mutex_unlock(&cache_chain_mutex);
1094 start_cpu_timer(cpu);
1096 #ifdef CONFIG_HOTPLUG_CPU
1099 * Even if all the cpus of a node are down, we don't free the
1100 * kmem_list3 of any cache. This to avoid a race between
1101 * cpu_down, and a kmalloc allocation from another cpu for
1102 * memory from the node of the cpu going down. The list3
1103 * structure is usually allocated from kmem_cache_create() and
1104 * gets destroyed at kmem_cache_destroy().
1107 case CPU_UP_CANCELED:
1108 mutex_lock(&cache_chain_mutex);
1109 list_for_each_entry(cachep, &cache_chain, next) {
1110 struct array_cache *nc;
1111 struct array_cache *shared;
1112 struct array_cache **alien;
1115 mask = node_to_cpumask(node);
1116 /* cpu is dead; no one can alloc from it. */
1117 nc = cachep->array[cpu];
1118 cachep->array[cpu] = NULL;
1119 l3 = cachep->nodelists[node];
1122 goto free_array_cache;
1124 spin_lock_irq(&l3->list_lock);
1126 /* Free limit for this kmem_list3 */
1127 l3->free_limit -= cachep->batchcount;
1129 free_block(cachep, nc->entry, nc->avail, node);
1131 if (!cpus_empty(mask)) {
1132 spin_unlock_irq(&l3->list_lock);
1133 goto free_array_cache;
1136 shared = l3->shared;
1138 free_block(cachep, l3->shared->entry,
1139 l3->shared->avail, node);
1146 spin_unlock_irq(&l3->list_lock);
1150 drain_alien_cache(cachep, alien);
1151 free_alien_cache(alien);
1157 * In the previous loop, all the objects were freed to
1158 * the respective cache's slabs, now we can go ahead and
1159 * shrink each nodelist to its limit.
1161 list_for_each_entry(cachep, &cache_chain, next) {
1162 l3 = cachep->nodelists[node];
1165 spin_lock_irq(&l3->list_lock);
1166 /* free slabs belonging to this node */
1167 __node_shrink(cachep, node);
1168 spin_unlock_irq(&l3->list_lock);
1170 mutex_unlock(&cache_chain_mutex);
1176 mutex_unlock(&cache_chain_mutex);
1180 static struct notifier_block cpucache_notifier = { &cpuup_callback, NULL, 0 };
1183 * swap the static kmem_list3 with kmalloced memory
1185 static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
1188 struct kmem_list3 *ptr;
1190 BUG_ON(cachep->nodelists[nodeid] != list);
1191 ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, nodeid);
1194 local_irq_disable();
1195 memcpy(ptr, list, sizeof(struct kmem_list3));
1196 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1197 cachep->nodelists[nodeid] = ptr;
1202 * Initialisation. Called after the page allocator have been initialised and
1203 * before smp_init().
1205 void __init kmem_cache_init(void)
1208 struct cache_sizes *sizes;
1209 struct cache_names *names;
1213 for (i = 0; i < NUM_INIT_LISTS; i++) {
1214 kmem_list3_init(&initkmem_list3[i]);
1215 if (i < MAX_NUMNODES)
1216 cache_cache.nodelists[i] = NULL;
1220 * Fragmentation resistance on low memory - only use bigger
1221 * page orders on machines with more than 32MB of memory.
1223 if (num_physpages > (32 << 20) >> PAGE_SHIFT)
1224 slab_break_gfp_order = BREAK_GFP_ORDER_HI;
1226 /* Bootstrap is tricky, because several objects are allocated
1227 * from caches that do not exist yet:
1228 * 1) initialize the cache_cache cache: it contains the struct
1229 * kmem_cache structures of all caches, except cache_cache itself:
1230 * cache_cache is statically allocated.
1231 * Initially an __init data area is used for the head array and the
1232 * kmem_list3 structures, it's replaced with a kmalloc allocated
1233 * array at the end of the bootstrap.
1234 * 2) Create the first kmalloc cache.
1235 * The struct kmem_cache for the new cache is allocated normally.
1236 * An __init data area is used for the head array.
1237 * 3) Create the remaining kmalloc caches, with minimally sized
1239 * 4) Replace the __init data head arrays for cache_cache and the first
1240 * kmalloc cache with kmalloc allocated arrays.
1241 * 5) Replace the __init data for kmem_list3 for cache_cache and
1242 * the other cache's with kmalloc allocated memory.
1243 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1246 /* 1) create the cache_cache */
1247 INIT_LIST_HEAD(&cache_chain);
1248 list_add(&cache_cache.next, &cache_chain);
1249 cache_cache.colour_off = cache_line_size();
1250 cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
1251 cache_cache.nodelists[numa_node_id()] = &initkmem_list3[CACHE_CACHE];
1253 cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
1256 for (order = 0; order < MAX_ORDER; order++) {
1257 cache_estimate(order, cache_cache.buffer_size,
1258 cache_line_size(), 0, &left_over, &cache_cache.num);
1259 if (cache_cache.num)
1262 if (!cache_cache.num)
1264 cache_cache.gfporder = order;
1265 cache_cache.colour = left_over / cache_cache.colour_off;
1266 cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
1267 sizeof(struct slab), cache_line_size());
1269 /* 2+3) create the kmalloc caches */
1270 sizes = malloc_sizes;
1271 names = cache_names;
1274 * Initialize the caches that provide memory for the array cache and the
1275 * kmem_list3 structures first. Without this, further allocations will
1279 sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name,
1280 sizes[INDEX_AC].cs_size,
1281 ARCH_KMALLOC_MINALIGN,
1282 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1285 if (INDEX_AC != INDEX_L3) {
1286 sizes[INDEX_L3].cs_cachep =
1287 kmem_cache_create(names[INDEX_L3].name,
1288 sizes[INDEX_L3].cs_size,
1289 ARCH_KMALLOC_MINALIGN,
1290 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1294 while (sizes->cs_size != ULONG_MAX) {
1296 * For performance, all the general caches are L1 aligned.
1297 * This should be particularly beneficial on SMP boxes, as it
1298 * eliminates "false sharing".
1299 * Note for systems short on memory removing the alignment will
1300 * allow tighter packing of the smaller caches.
1302 if (!sizes->cs_cachep) {
1303 sizes->cs_cachep = kmem_cache_create(names->name,
1305 ARCH_KMALLOC_MINALIGN,
1306 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1310 /* Inc off-slab bufctl limit until the ceiling is hit. */
1311 if (!(OFF_SLAB(sizes->cs_cachep))) {
1312 offslab_limit = sizes->cs_size - sizeof(struct slab);
1313 offslab_limit /= sizeof(kmem_bufctl_t);
1316 sizes->cs_dmacachep = kmem_cache_create(names->name_dma,
1318 ARCH_KMALLOC_MINALIGN,
1319 ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
1325 /* 4) Replace the bootstrap head arrays */
1329 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1331 local_irq_disable();
1332 BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
1333 memcpy(ptr, cpu_cache_get(&cache_cache),
1334 sizeof(struct arraycache_init));
1335 cache_cache.array[smp_processor_id()] = ptr;
1338 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1340 local_irq_disable();
1341 BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
1342 != &initarray_generic.cache);
1343 memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
1344 sizeof(struct arraycache_init));
1345 malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
1349 /* 5) Replace the bootstrap kmem_list3's */
1352 /* Replace the static kmem_list3 structures for the boot cpu */
1353 init_list(&cache_cache, &initkmem_list3[CACHE_CACHE],
1356 for_each_online_node(node) {
1357 init_list(malloc_sizes[INDEX_AC].cs_cachep,
1358 &initkmem_list3[SIZE_AC + node], node);
1360 if (INDEX_AC != INDEX_L3) {
1361 init_list(malloc_sizes[INDEX_L3].cs_cachep,
1362 &initkmem_list3[SIZE_L3 + node],
1368 /* 6) resize the head arrays to their final sizes */
1370 struct kmem_cache *cachep;
1371 mutex_lock(&cache_chain_mutex);
1372 list_for_each_entry(cachep, &cache_chain, next)
1373 enable_cpucache(cachep);
1374 mutex_unlock(&cache_chain_mutex);
1378 g_cpucache_up = FULL;
1381 * Register a cpu startup notifier callback that initializes
1382 * cpu_cache_get for all new cpus
1384 register_cpu_notifier(&cpucache_notifier);
1387 * The reap timers are started later, with a module init call: That part
1388 * of the kernel is not yet operational.
1392 static int __init cpucache_init(void)
1397 * Register the timers that return unneeded pages to the page allocator
1399 for_each_online_cpu(cpu)
1400 start_cpu_timer(cpu);
1403 __initcall(cpucache_init);
1406 * Interface to system's page allocator. No need to hold the cache-lock.
1408 * If we requested dmaable memory, we will get it. Even if we
1409 * did not request dmaable memory, we might get it, but that
1410 * would be relatively rare and ignorable.
1412 static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
1418 flags |= cachep->gfpflags;
1419 page = alloc_pages_node(nodeid, flags, cachep->gfporder);
1422 addr = page_address(page);
1424 i = (1 << cachep->gfporder);
1425 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1426 atomic_add(i, &slab_reclaim_pages);
1427 add_page_state(nr_slab, i);
1429 __SetPageSlab(page);
1436 * Interface to system's page release.
1438 static void kmem_freepages(struct kmem_cache *cachep, void *addr)
1440 unsigned long i = (1 << cachep->gfporder);
1441 struct page *page = virt_to_page(addr);
1442 const unsigned long nr_freed = i;
1445 BUG_ON(!PageSlab(page));
1446 __ClearPageSlab(page);
1449 sub_page_state(nr_slab, nr_freed);
1450 if (current->reclaim_state)
1451 current->reclaim_state->reclaimed_slab += nr_freed;
1452 free_pages((unsigned long)addr, cachep->gfporder);
1453 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1454 atomic_sub(1 << cachep->gfporder, &slab_reclaim_pages);
1457 static void kmem_rcu_free(struct rcu_head *head)
1459 struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
1460 struct kmem_cache *cachep = slab_rcu->cachep;
1462 kmem_freepages(cachep, slab_rcu->addr);
1463 if (OFF_SLAB(cachep))
1464 kmem_cache_free(cachep->slabp_cache, slab_rcu);
1469 #ifdef CONFIG_DEBUG_PAGEALLOC
1470 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1471 unsigned long caller)
1473 int size = obj_size(cachep);
1475 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1477 if (size < 5 * sizeof(unsigned long))
1480 *addr++ = 0x12345678;
1482 *addr++ = smp_processor_id();
1483 size -= 3 * sizeof(unsigned long);
1485 unsigned long *sptr = &caller;
1486 unsigned long svalue;
1488 while (!kstack_end(sptr)) {
1490 if (kernel_text_address(svalue)) {
1492 size -= sizeof(unsigned long);
1493 if (size <= sizeof(unsigned long))
1499 *addr++ = 0x87654321;
1503 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1505 int size = obj_size(cachep);
1506 addr = &((char *)addr)[obj_offset(cachep)];
1508 memset(addr, val, size);
1509 *(unsigned char *)(addr + size - 1) = POISON_END;
1512 static void dump_line(char *data, int offset, int limit)
1515 printk(KERN_ERR "%03x:", offset);
1516 for (i = 0; i < limit; i++)
1517 printk(" %02x", (unsigned char)data[offset + i]);
1524 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1529 if (cachep->flags & SLAB_RED_ZONE) {
1530 printk(KERN_ERR "Redzone: 0x%lx/0x%lx.\n",
1531 *dbg_redzone1(cachep, objp),
1532 *dbg_redzone2(cachep, objp));
1535 if (cachep->flags & SLAB_STORE_USER) {
1536 printk(KERN_ERR "Last user: [<%p>]",
1537 *dbg_userword(cachep, objp));
1538 print_symbol("(%s)",
1539 (unsigned long)*dbg_userword(cachep, objp));
1542 realobj = (char *)objp + obj_offset(cachep);
1543 size = obj_size(cachep);
1544 for (i = 0; i < size && lines; i += 16, lines--) {
1547 if (i + limit > size)
1549 dump_line(realobj, i, limit);
1553 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1559 realobj = (char *)objp + obj_offset(cachep);
1560 size = obj_size(cachep);
1562 for (i = 0; i < size; i++) {
1563 char exp = POISON_FREE;
1566 if (realobj[i] != exp) {
1572 "Slab corruption: start=%p, len=%d\n",
1574 print_objinfo(cachep, objp, 0);
1576 /* Hexdump the affected line */
1579 if (i + limit > size)
1581 dump_line(realobj, i, limit);
1584 /* Limit to 5 lines */
1590 /* Print some data about the neighboring objects, if they
1593 struct slab *slabp = virt_to_slab(objp);
1596 objnr = obj_to_index(cachep, slabp, objp);
1598 objp = index_to_obj(cachep, slabp, objnr - 1);
1599 realobj = (char *)objp + obj_offset(cachep);
1600 printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1602 print_objinfo(cachep, objp, 2);
1604 if (objnr + 1 < cachep->num) {
1605 objp = index_to_obj(cachep, slabp, objnr + 1);
1606 realobj = (char *)objp + obj_offset(cachep);
1607 printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1609 print_objinfo(cachep, objp, 2);
1617 * slab_destroy_objs - call the registered destructor for each object in
1618 * a slab that is to be destroyed.
1620 static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
1623 for (i = 0; i < cachep->num; i++) {
1624 void *objp = index_to_obj(cachep, slabp, i);
1626 if (cachep->flags & SLAB_POISON) {
1627 #ifdef CONFIG_DEBUG_PAGEALLOC
1628 if (cachep->buffer_size % PAGE_SIZE == 0 &&
1630 kernel_map_pages(virt_to_page(objp),
1631 cachep->buffer_size / PAGE_SIZE, 1);
1633 check_poison_obj(cachep, objp);
1635 check_poison_obj(cachep, objp);
1638 if (cachep->flags & SLAB_RED_ZONE) {
1639 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1640 slab_error(cachep, "start of a freed object "
1642 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1643 slab_error(cachep, "end of a freed object "
1646 if (cachep->dtor && !(cachep->flags & SLAB_POISON))
1647 (cachep->dtor) (objp + obj_offset(cachep), cachep, 0);
1651 static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
1655 for (i = 0; i < cachep->num; i++) {
1656 void *objp = index_to_obj(cachep, slabp, i);
1657 (cachep->dtor) (objp, cachep, 0);
1664 * Destroy all the objs in a slab, and release the mem back to the system.
1665 * Before calling the slab must have been unlinked from the cache. The
1666 * cache-lock is not held/needed.
1668 static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
1670 void *addr = slabp->s_mem - slabp->colouroff;
1672 slab_destroy_objs(cachep, slabp);
1673 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
1674 struct slab_rcu *slab_rcu;
1676 slab_rcu = (struct slab_rcu *)slabp;
1677 slab_rcu->cachep = cachep;
1678 slab_rcu->addr = addr;
1679 call_rcu(&slab_rcu->head, kmem_rcu_free);
1681 kmem_freepages(cachep, addr);
1682 if (OFF_SLAB(cachep))
1683 kmem_cache_free(cachep->slabp_cache, slabp);
1688 * For setting up all the kmem_list3s for cache whose buffer_size is same as
1689 * size of kmem_list3.
1691 static void set_up_list3s(struct kmem_cache *cachep, int index)
1695 for_each_online_node(node) {
1696 cachep->nodelists[node] = &initkmem_list3[index + node];
1697 cachep->nodelists[node]->next_reap = jiffies +
1699 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1704 * calculate_slab_order - calculate size (page order) of slabs
1705 * @cachep: pointer to the cache that is being created
1706 * @size: size of objects to be created in this cache.
1707 * @align: required alignment for the objects.
1708 * @flags: slab allocation flags
1710 * Also calculates the number of objects per slab.
1712 * This could be made much more intelligent. For now, try to avoid using
1713 * high order pages for slabs. When the gfp() functions are more friendly
1714 * towards high-order requests, this should be changed.
1716 static size_t calculate_slab_order(struct kmem_cache *cachep,
1717 size_t size, size_t align, unsigned long flags)
1719 size_t left_over = 0;
1722 for (gfporder = 0; gfporder <= MAX_GFP_ORDER; gfporder++) {
1726 cache_estimate(gfporder, size, align, flags, &remainder, &num);
1730 /* More than offslab_limit objects will cause problems */
1731 if ((flags & CFLGS_OFF_SLAB) && num > offslab_limit)
1734 /* Found something acceptable - save it away */
1736 cachep->gfporder = gfporder;
1737 left_over = remainder;
1740 * A VFS-reclaimable slab tends to have most allocations
1741 * as GFP_NOFS and we really don't want to have to be allocating
1742 * higher-order pages when we are unable to shrink dcache.
1744 if (flags & SLAB_RECLAIM_ACCOUNT)
1748 * Large number of objects is good, but very large slabs are
1749 * currently bad for the gfp()s.
1751 if (gfporder >= slab_break_gfp_order)
1755 * Acceptable internal fragmentation?
1757 if (left_over * 8 <= (PAGE_SIZE << gfporder))
1763 static void setup_cpu_cache(struct kmem_cache *cachep)
1765 if (g_cpucache_up == FULL) {
1766 enable_cpucache(cachep);
1769 if (g_cpucache_up == NONE) {
1771 * Note: the first kmem_cache_create must create the cache
1772 * that's used by kmalloc(24), otherwise the creation of
1773 * further caches will BUG().
1775 cachep->array[smp_processor_id()] = &initarray_generic.cache;
1778 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
1779 * the first cache, then we need to set up all its list3s,
1780 * otherwise the creation of further caches will BUG().
1782 set_up_list3s(cachep, SIZE_AC);
1783 if (INDEX_AC == INDEX_L3)
1784 g_cpucache_up = PARTIAL_L3;
1786 g_cpucache_up = PARTIAL_AC;
1788 cachep->array[smp_processor_id()] =
1789 kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1791 if (g_cpucache_up == PARTIAL_AC) {
1792 set_up_list3s(cachep, SIZE_L3);
1793 g_cpucache_up = PARTIAL_L3;
1796 for_each_online_node(node) {
1797 cachep->nodelists[node] =
1798 kmalloc_node(sizeof(struct kmem_list3),
1800 BUG_ON(!cachep->nodelists[node]);
1801 kmem_list3_init(cachep->nodelists[node]);
1805 cachep->nodelists[numa_node_id()]->next_reap =
1806 jiffies + REAPTIMEOUT_LIST3 +
1807 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1809 cpu_cache_get(cachep)->avail = 0;
1810 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
1811 cpu_cache_get(cachep)->batchcount = 1;
1812 cpu_cache_get(cachep)->touched = 0;
1813 cachep->batchcount = 1;
1814 cachep->limit = BOOT_CPUCACHE_ENTRIES;
1818 * kmem_cache_create - Create a cache.
1819 * @name: A string which is used in /proc/slabinfo to identify this cache.
1820 * @size: The size of objects to be created in this cache.
1821 * @align: The required alignment for the objects.
1822 * @flags: SLAB flags
1823 * @ctor: A constructor for the objects.
1824 * @dtor: A destructor for the objects.
1826 * Returns a ptr to the cache on success, NULL on failure.
1827 * Cannot be called within a int, but can be interrupted.
1828 * The @ctor is run when new pages are allocated by the cache
1829 * and the @dtor is run before the pages are handed back.
1831 * @name must be valid until the cache is destroyed. This implies that
1832 * the module calling this has to destroy the cache before getting unloaded.
1836 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
1837 * to catch references to uninitialised memory.
1839 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
1840 * for buffer overruns.
1842 * %SLAB_NO_REAP - Don't automatically reap this cache when we're under
1845 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
1846 * cacheline. This can be beneficial if you're counting cycles as closely
1850 kmem_cache_create (const char *name, size_t size, size_t align,
1851 unsigned long flags,
1852 void (*ctor)(void*, struct kmem_cache *, unsigned long),
1853 void (*dtor)(void*, struct kmem_cache *, unsigned long))
1855 size_t left_over, slab_size, ralign;
1856 struct kmem_cache *cachep = NULL;
1857 struct list_head *p;
1860 * Sanity checks... these are all serious usage bugs.
1862 if (!name || in_interrupt() || (size < BYTES_PER_WORD) ||
1863 (size > (1 << MAX_OBJ_ORDER) * PAGE_SIZE) || (dtor && !ctor)) {
1864 printk(KERN_ERR "%s: Early error in slab %s\n", __FUNCTION__,
1870 * Prevent CPUs from coming and going.
1871 * lock_cpu_hotplug() nests outside cache_chain_mutex
1875 mutex_lock(&cache_chain_mutex);
1877 list_for_each(p, &cache_chain) {
1878 struct kmem_cache *pc = list_entry(p, struct kmem_cache, next);
1879 mm_segment_t old_fs = get_fs();
1884 * This happens when the module gets unloaded and doesn't
1885 * destroy its slab cache and no-one else reuses the vmalloc
1886 * area of the module. Print a warning.
1889 res = __get_user(tmp, pc->name);
1892 printk("SLAB: cache with size %d has lost its name\n",
1897 if (!strcmp(pc->name, name)) {
1898 printk("kmem_cache_create: duplicate cache %s\n", name);
1905 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
1906 if ((flags & SLAB_DEBUG_INITIAL) && !ctor) {
1907 /* No constructor, but inital state check requested */
1908 printk(KERN_ERR "%s: No con, but init state check "
1909 "requested - %s\n", __FUNCTION__, name);
1910 flags &= ~SLAB_DEBUG_INITIAL;
1914 * Enable redzoning and last user accounting, except for caches with
1915 * large objects, if the increased size would increase the object size
1916 * above the next power of two: caches with object sizes just above a
1917 * power of two have a significant amount of internal fragmentation.
1919 if (size < 4096 || fls(size - 1) == fls(size-1 + 3 * BYTES_PER_WORD))
1920 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
1921 if (!(flags & SLAB_DESTROY_BY_RCU))
1922 flags |= SLAB_POISON;
1924 if (flags & SLAB_DESTROY_BY_RCU)
1925 BUG_ON(flags & SLAB_POISON);
1927 if (flags & SLAB_DESTROY_BY_RCU)
1931 * Always checks flags, a caller might be expecting debug support which
1934 if (flags & ~CREATE_MASK)
1938 * Check that size is in terms of words. This is needed to avoid
1939 * unaligned accesses for some archs when redzoning is used, and makes
1940 * sure any on-slab bufctl's are also correctly aligned.
1942 if (size & (BYTES_PER_WORD - 1)) {
1943 size += (BYTES_PER_WORD - 1);
1944 size &= ~(BYTES_PER_WORD - 1);
1947 /* calculate the final buffer alignment: */
1949 /* 1) arch recommendation: can be overridden for debug */
1950 if (flags & SLAB_HWCACHE_ALIGN) {
1952 * Default alignment: as specified by the arch code. Except if
1953 * an object is really small, then squeeze multiple objects into
1956 ralign = cache_line_size();
1957 while (size <= ralign / 2)
1960 ralign = BYTES_PER_WORD;
1962 /* 2) arch mandated alignment: disables debug if necessary */
1963 if (ralign < ARCH_SLAB_MINALIGN) {
1964 ralign = ARCH_SLAB_MINALIGN;
1965 if (ralign > BYTES_PER_WORD)
1966 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
1968 /* 3) caller mandated alignment: disables debug if necessary */
1969 if (ralign < align) {
1971 if (ralign > BYTES_PER_WORD)
1972 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
1975 * 4) Store it. Note that the debug code below can reduce
1976 * the alignment to BYTES_PER_WORD.
1980 /* Get cache's description obj. */
1981 cachep = kmem_cache_alloc(&cache_cache, SLAB_KERNEL);
1984 memset(cachep, 0, sizeof(struct kmem_cache));
1987 cachep->obj_size = size;
1989 if (flags & SLAB_RED_ZONE) {
1990 /* redzoning only works with word aligned caches */
1991 align = BYTES_PER_WORD;
1993 /* add space for red zone words */
1994 cachep->obj_offset += BYTES_PER_WORD;
1995 size += 2 * BYTES_PER_WORD;
1997 if (flags & SLAB_STORE_USER) {
1998 /* user store requires word alignment and
1999 * one word storage behind the end of the real
2002 align = BYTES_PER_WORD;
2003 size += BYTES_PER_WORD;
2005 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2006 if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
2007 && cachep->obj_size > cache_line_size() && size < PAGE_SIZE) {
2008 cachep->obj_offset += PAGE_SIZE - size;
2014 /* Determine if the slab management is 'on' or 'off' slab. */
2015 if (size >= (PAGE_SIZE >> 3))
2017 * Size is large, assume best to place the slab management obj
2018 * off-slab (should allow better packing of objs).
2020 flags |= CFLGS_OFF_SLAB;
2022 size = ALIGN(size, align);
2024 left_over = calculate_slab_order(cachep, size, align, flags);
2027 printk("kmem_cache_create: couldn't create cache %s.\n", name);
2028 kmem_cache_free(&cache_cache, cachep);
2032 slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
2033 + sizeof(struct slab), align);
2036 * If the slab has been placed off-slab, and we have enough space then
2037 * move it on-slab. This is at the expense of any extra colouring.
2039 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
2040 flags &= ~CFLGS_OFF_SLAB;
2041 left_over -= slab_size;
2044 if (flags & CFLGS_OFF_SLAB) {
2045 /* really off slab. No need for manual alignment */
2047 cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
2050 cachep->colour_off = cache_line_size();
2051 /* Offset must be a multiple of the alignment. */
2052 if (cachep->colour_off < align)
2053 cachep->colour_off = align;
2054 cachep->colour = left_over / cachep->colour_off;
2055 cachep->slab_size = slab_size;
2056 cachep->flags = flags;
2057 cachep->gfpflags = 0;
2058 if (flags & SLAB_CACHE_DMA)
2059 cachep->gfpflags |= GFP_DMA;
2060 spin_lock_init(&cachep->spinlock);
2061 cachep->buffer_size = size;
2063 if (flags & CFLGS_OFF_SLAB)
2064 cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
2065 cachep->ctor = ctor;
2066 cachep->dtor = dtor;
2067 cachep->name = name;
2070 setup_cpu_cache(cachep);
2072 /* cache setup completed, link it into the list */
2073 list_add(&cachep->next, &cache_chain);
2075 if (!cachep && (flags & SLAB_PANIC))
2076 panic("kmem_cache_create(): failed to create slab `%s'\n",
2078 mutex_unlock(&cache_chain_mutex);
2079 unlock_cpu_hotplug();
2082 EXPORT_SYMBOL(kmem_cache_create);
2085 static void check_irq_off(void)
2087 BUG_ON(!irqs_disabled());
2090 static void check_irq_on(void)
2092 BUG_ON(irqs_disabled());
2095 static void check_spinlock_acquired(struct kmem_cache *cachep)
2099 assert_spin_locked(&cachep->nodelists[numa_node_id()]->list_lock);
2103 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2107 assert_spin_locked(&cachep->nodelists[node]->list_lock);
2112 #define check_irq_off() do { } while(0)
2113 #define check_irq_on() do { } while(0)
2114 #define check_spinlock_acquired(x) do { } while(0)
2115 #define check_spinlock_acquired_node(x, y) do { } while(0)
2119 * Waits for all CPUs to execute func().
2121 static void smp_call_function_all_cpus(void (*func)(void *arg), void *arg)
2125 local_irq_disable();
2129 if (smp_call_function(func, arg, 1, 1))
2135 static void drain_array_locked(struct kmem_cache *cachep,
2136 struct array_cache *ac, int force, int node);
2138 static void do_drain(void *arg)
2140 struct kmem_cache *cachep = arg;
2141 struct array_cache *ac;
2142 int node = numa_node_id();
2145 ac = cpu_cache_get(cachep);
2146 spin_lock(&cachep->nodelists[node]->list_lock);
2147 free_block(cachep, ac->entry, ac->avail, node);
2148 spin_unlock(&cachep->nodelists[node]->list_lock);
2152 static void drain_cpu_caches(struct kmem_cache *cachep)
2154 struct kmem_list3 *l3;
2157 smp_call_function_all_cpus(do_drain, cachep);
2159 for_each_online_node(node) {
2160 l3 = cachep->nodelists[node];
2162 spin_lock_irq(&l3->list_lock);
2163 drain_array_locked(cachep, l3->shared, 1, node);
2164 spin_unlock_irq(&l3->list_lock);
2166 drain_alien_cache(cachep, l3->alien);
2171 static int __node_shrink(struct kmem_cache *cachep, int node)
2174 struct kmem_list3 *l3 = cachep->nodelists[node];
2178 struct list_head *p;
2180 p = l3->slabs_free.prev;
2181 if (p == &l3->slabs_free)
2184 slabp = list_entry(l3->slabs_free.prev, struct slab, list);
2189 list_del(&slabp->list);
2191 l3->free_objects -= cachep->num;
2192 spin_unlock_irq(&l3->list_lock);
2193 slab_destroy(cachep, slabp);
2194 spin_lock_irq(&l3->list_lock);
2196 ret = !list_empty(&l3->slabs_full) || !list_empty(&l3->slabs_partial);
2200 static int __cache_shrink(struct kmem_cache *cachep)
2203 struct kmem_list3 *l3;
2205 drain_cpu_caches(cachep);
2208 for_each_online_node(i) {
2209 l3 = cachep->nodelists[i];
2211 spin_lock_irq(&l3->list_lock);
2212 ret += __node_shrink(cachep, i);
2213 spin_unlock_irq(&l3->list_lock);
2216 return (ret ? 1 : 0);
2220 * kmem_cache_shrink - Shrink a cache.
2221 * @cachep: The cache to shrink.
2223 * Releases as many slabs as possible for a cache.
2224 * To help debugging, a zero exit status indicates all slabs were released.
2226 int kmem_cache_shrink(struct kmem_cache *cachep)
2228 if (!cachep || in_interrupt())
2231 return __cache_shrink(cachep);
2233 EXPORT_SYMBOL(kmem_cache_shrink);
2236 * kmem_cache_destroy - delete a cache
2237 * @cachep: the cache to destroy
2239 * Remove a struct kmem_cache object from the slab cache.
2240 * Returns 0 on success.
2242 * It is expected this function will be called by a module when it is
2243 * unloaded. This will remove the cache completely, and avoid a duplicate
2244 * cache being allocated each time a module is loaded and unloaded, if the
2245 * module doesn't have persistent in-kernel storage across loads and unloads.
2247 * The cache must be empty before calling this function.
2249 * The caller must guarantee that noone will allocate memory from the cache
2250 * during the kmem_cache_destroy().
2252 int kmem_cache_destroy(struct kmem_cache *cachep)
2255 struct kmem_list3 *l3;
2257 if (!cachep || in_interrupt())
2260 /* Don't let CPUs to come and go */
2263 /* Find the cache in the chain of caches. */
2264 mutex_lock(&cache_chain_mutex);
2266 * the chain is never empty, cache_cache is never destroyed
2268 list_del(&cachep->next);
2269 mutex_unlock(&cache_chain_mutex);
2271 if (__cache_shrink(cachep)) {
2272 slab_error(cachep, "Can't free all objects");
2273 mutex_lock(&cache_chain_mutex);
2274 list_add(&cachep->next, &cache_chain);
2275 mutex_unlock(&cache_chain_mutex);
2276 unlock_cpu_hotplug();
2280 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
2283 for_each_online_cpu(i)
2284 kfree(cachep->array[i]);
2286 /* NUMA: free the list3 structures */
2287 for_each_online_node(i) {
2288 l3 = cachep->nodelists[i];
2291 free_alien_cache(l3->alien);
2295 kmem_cache_free(&cache_cache, cachep);
2296 unlock_cpu_hotplug();
2299 EXPORT_SYMBOL(kmem_cache_destroy);
2301 /* Get the memory for a slab management obj. */
2302 static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,
2303 int colour_off, gfp_t local_flags)
2307 if (OFF_SLAB(cachep)) {
2308 /* Slab management obj is off-slab. */
2309 slabp = kmem_cache_alloc(cachep->slabp_cache, local_flags);
2313 slabp = objp + colour_off;
2314 colour_off += cachep->slab_size;
2317 slabp->colouroff = colour_off;
2318 slabp->s_mem = objp + colour_off;
2322 static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
2324 return (kmem_bufctl_t *) (slabp + 1);
2327 static void cache_init_objs(struct kmem_cache *cachep,
2328 struct slab *slabp, unsigned long ctor_flags)
2332 for (i = 0; i < cachep->num; i++) {
2333 void *objp = index_to_obj(cachep, slabp, i);
2335 /* need to poison the objs? */
2336 if (cachep->flags & SLAB_POISON)
2337 poison_obj(cachep, objp, POISON_FREE);
2338 if (cachep->flags & SLAB_STORE_USER)
2339 *dbg_userword(cachep, objp) = NULL;
2341 if (cachep->flags & SLAB_RED_ZONE) {
2342 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2343 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2346 * Constructors are not allowed to allocate memory from the same
2347 * cache which they are a constructor for. Otherwise, deadlock.
2348 * They must also be threaded.
2350 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2351 cachep->ctor(objp + obj_offset(cachep), cachep,
2354 if (cachep->flags & SLAB_RED_ZONE) {
2355 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2356 slab_error(cachep, "constructor overwrote the"
2357 " end of an object");
2358 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2359 slab_error(cachep, "constructor overwrote the"
2360 " start of an object");
2362 if ((cachep->buffer_size % PAGE_SIZE) == 0 &&
2363 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2364 kernel_map_pages(virt_to_page(objp),
2365 cachep->buffer_size / PAGE_SIZE, 0);
2368 cachep->ctor(objp, cachep, ctor_flags);
2370 slab_bufctl(slabp)[i] = i + 1;
2372 slab_bufctl(slabp)[i - 1] = BUFCTL_END;
2376 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2378 if (flags & SLAB_DMA)
2379 BUG_ON(!(cachep->gfpflags & GFP_DMA));
2381 BUG_ON(cachep->gfpflags & GFP_DMA);
2384 static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
2387 void *objp = index_to_obj(cachep, slabp, slabp->free);
2391 next = slab_bufctl(slabp)[slabp->free];
2393 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2394 WARN_ON(slabp->nodeid != nodeid);
2401 static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
2402 void *objp, int nodeid)
2404 unsigned int objnr = obj_to_index(cachep, slabp, objp);
2407 /* Verify that the slab belongs to the intended node */
2408 WARN_ON(slabp->nodeid != nodeid);
2410 if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
2411 printk(KERN_ERR "slab: double free detected in cache "
2412 "'%s', objp %p\n", cachep->name, objp);
2416 slab_bufctl(slabp)[objnr] = slabp->free;
2417 slabp->free = objnr;
2421 static void set_slab_attr(struct kmem_cache *cachep, struct slab *slabp,
2427 /* Nasty!!!!!! I hope this is OK. */
2428 i = 1 << cachep->gfporder;
2429 page = virt_to_page(objp);
2431 page_set_cache(page, cachep);
2432 page_set_slab(page, slabp);
2438 * Grow (by 1) the number of slabs within a cache. This is called by
2439 * kmem_cache_alloc() when there are no active objs left in a cache.
2441 static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid)
2447 unsigned long ctor_flags;
2448 struct kmem_list3 *l3;
2451 * Be lazy and only check for valid flags here, keeping it out of the
2452 * critical path in kmem_cache_alloc().
2454 if (flags & ~(SLAB_DMA | SLAB_LEVEL_MASK | SLAB_NO_GROW))
2456 if (flags & SLAB_NO_GROW)
2459 ctor_flags = SLAB_CTOR_CONSTRUCTOR;
2460 local_flags = (flags & SLAB_LEVEL_MASK);
2461 if (!(local_flags & __GFP_WAIT))
2463 * Not allowed to sleep. Need to tell a constructor about
2464 * this - it might need to know...
2466 ctor_flags |= SLAB_CTOR_ATOMIC;
2468 /* Take the l3 list lock to change the colour_next on this node */
2470 l3 = cachep->nodelists[nodeid];
2471 spin_lock(&l3->list_lock);
2473 /* Get colour for the slab, and cal the next value. */
2474 offset = l3->colour_next;
2476 if (l3->colour_next >= cachep->colour)
2477 l3->colour_next = 0;
2478 spin_unlock(&l3->list_lock);
2480 offset *= cachep->colour_off;
2482 if (local_flags & __GFP_WAIT)
2486 * The test for missing atomic flag is performed here, rather than
2487 * the more obvious place, simply to reduce the critical path length
2488 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2489 * will eventually be caught here (where it matters).
2491 kmem_flagcheck(cachep, flags);
2494 * Get mem for the objs. Attempt to allocate a physical page from
2497 objp = kmem_getpages(cachep, flags, nodeid);
2501 /* Get slab management. */
2502 slabp = alloc_slabmgmt(cachep, objp, offset, local_flags);
2506 slabp->nodeid = nodeid;
2507 set_slab_attr(cachep, slabp, objp);
2509 cache_init_objs(cachep, slabp, ctor_flags);
2511 if (local_flags & __GFP_WAIT)
2512 local_irq_disable();
2514 spin_lock(&l3->list_lock);
2516 /* Make slab active. */
2517 list_add_tail(&slabp->list, &(l3->slabs_free));
2518 STATS_INC_GROWN(cachep);
2519 l3->free_objects += cachep->num;
2520 spin_unlock(&l3->list_lock);
2523 kmem_freepages(cachep, objp);
2525 if (local_flags & __GFP_WAIT)
2526 local_irq_disable();
2533 * Perform extra freeing checks:
2534 * - detect bad pointers.
2535 * - POISON/RED_ZONE checking
2536 * - destructor calls, for caches with POISON+dtor
2538 static void kfree_debugcheck(const void *objp)
2542 if (!virt_addr_valid(objp)) {
2543 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2544 (unsigned long)objp);
2547 page = virt_to_page(objp);
2548 if (!PageSlab(page)) {
2549 printk(KERN_ERR "kfree_debugcheck: bad ptr %lxh.\n",
2550 (unsigned long)objp);
2555 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2562 objp -= obj_offset(cachep);
2563 kfree_debugcheck(objp);
2564 page = virt_to_page(objp);
2566 if (page_get_cache(page) != cachep) {
2567 printk(KERN_ERR "mismatch in kmem_cache_free: expected "
2568 "cache %p, got %p\n",
2569 page_get_cache(page), cachep);
2570 printk(KERN_ERR "%p is %s.\n", cachep, cachep->name);
2571 printk(KERN_ERR "%p is %s.\n", page_get_cache(page),
2572 page_get_cache(page)->name);
2575 slabp = page_get_slab(page);
2577 if (cachep->flags & SLAB_RED_ZONE) {
2578 if (*dbg_redzone1(cachep, objp) != RED_ACTIVE ||
2579 *dbg_redzone2(cachep, objp) != RED_ACTIVE) {
2580 slab_error(cachep, "double free, or memory outside"
2581 " object was overwritten");
2582 printk(KERN_ERR "%p: redzone 1:0x%lx, "
2583 "redzone 2:0x%lx.\n",
2584 objp, *dbg_redzone1(cachep, objp),
2585 *dbg_redzone2(cachep, objp));
2587 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2588 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2590 if (cachep->flags & SLAB_STORE_USER)
2591 *dbg_userword(cachep, objp) = caller;
2593 objnr = obj_to_index(cachep, slabp, objp);
2595 BUG_ON(objnr >= cachep->num);
2596 BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
2598 if (cachep->flags & SLAB_DEBUG_INITIAL) {
2600 * Need to call the slab's constructor so the caller can
2601 * perform a verify of its state (debugging). Called without
2602 * the cache-lock held.
2604 cachep->ctor(objp + obj_offset(cachep),
2605 cachep, SLAB_CTOR_CONSTRUCTOR | SLAB_CTOR_VERIFY);
2607 if (cachep->flags & SLAB_POISON && cachep->dtor) {
2608 /* we want to cache poison the object,
2609 * call the destruction callback
2611 cachep->dtor(objp + obj_offset(cachep), cachep, 0);
2613 if (cachep->flags & SLAB_POISON) {
2614 #ifdef CONFIG_DEBUG_PAGEALLOC
2615 if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2616 store_stackinfo(cachep, objp, (unsigned long)caller);
2617 kernel_map_pages(virt_to_page(objp),
2618 cachep->buffer_size / PAGE_SIZE, 0);
2620 poison_obj(cachep, objp, POISON_FREE);
2623 poison_obj(cachep, objp, POISON_FREE);
2629 static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
2634 /* Check slab's freelist to see if this obj is there. */
2635 for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
2637 if (entries > cachep->num || i >= cachep->num)
2640 if (entries != cachep->num - slabp->inuse) {
2642 printk(KERN_ERR "slab: Internal list corruption detected in "
2643 "cache '%s'(%d), slabp %p(%d). Hexdump:\n",
2644 cachep->name, cachep->num, slabp, slabp->inuse);
2646 i < sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t);
2649 printk("\n%03x:", i);
2650 printk(" %02x", ((unsigned char *)slabp)[i]);
2657 #define kfree_debugcheck(x) do { } while(0)
2658 #define cache_free_debugcheck(x,objp,z) (objp)
2659 #define check_slabp(x,y) do { } while(0)
2662 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
2665 struct kmem_list3 *l3;
2666 struct array_cache *ac;
2669 ac = cpu_cache_get(cachep);
2671 batchcount = ac->batchcount;
2672 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2674 * If there was little recent activity on this cache, then
2675 * perform only a partial refill. Otherwise we could generate
2678 batchcount = BATCHREFILL_LIMIT;
2680 l3 = cachep->nodelists[numa_node_id()];
2682 BUG_ON(ac->avail > 0 || !l3);
2683 spin_lock(&l3->list_lock);
2686 struct array_cache *shared_array = l3->shared;
2687 if (shared_array->avail) {
2688 if (batchcount > shared_array->avail)
2689 batchcount = shared_array->avail;
2690 shared_array->avail -= batchcount;
2691 ac->avail = batchcount;
2693 &(shared_array->entry[shared_array->avail]),
2694 sizeof(void *) * batchcount);
2695 shared_array->touched = 1;
2699 while (batchcount > 0) {
2700 struct list_head *entry;
2702 /* Get slab alloc is to come from. */
2703 entry = l3->slabs_partial.next;
2704 if (entry == &l3->slabs_partial) {
2705 l3->free_touched = 1;
2706 entry = l3->slabs_free.next;
2707 if (entry == &l3->slabs_free)
2711 slabp = list_entry(entry, struct slab, list);
2712 check_slabp(cachep, slabp);
2713 check_spinlock_acquired(cachep);
2714 while (slabp->inuse < cachep->num && batchcount--) {
2715 STATS_INC_ALLOCED(cachep);
2716 STATS_INC_ACTIVE(cachep);
2717 STATS_SET_HIGH(cachep);
2719 ac->entry[ac->avail++] = slab_get_obj(cachep, slabp,
2722 check_slabp(cachep, slabp);
2724 /* move slabp to correct slabp list: */
2725 list_del(&slabp->list);
2726 if (slabp->free == BUFCTL_END)
2727 list_add(&slabp->list, &l3->slabs_full);
2729 list_add(&slabp->list, &l3->slabs_partial);
2733 l3->free_objects -= ac->avail;
2735 spin_unlock(&l3->list_lock);
2737 if (unlikely(!ac->avail)) {
2739 x = cache_grow(cachep, flags, numa_node_id());
2741 /* cache_grow can reenable interrupts, then ac could change. */
2742 ac = cpu_cache_get(cachep);
2743 if (!x && ac->avail == 0) /* no objects in sight? abort */
2746 if (!ac->avail) /* objects refilled by interrupt? */
2750 return ac->entry[--ac->avail];
2753 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
2756 might_sleep_if(flags & __GFP_WAIT);
2758 kmem_flagcheck(cachep, flags);
2763 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
2764 gfp_t flags, void *objp, void *caller)
2768 if (cachep->flags & SLAB_POISON) {
2769 #ifdef CONFIG_DEBUG_PAGEALLOC
2770 if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
2771 kernel_map_pages(virt_to_page(objp),
2772 cachep->buffer_size / PAGE_SIZE, 1);
2774 check_poison_obj(cachep, objp);
2776 check_poison_obj(cachep, objp);
2778 poison_obj(cachep, objp, POISON_INUSE);
2780 if (cachep->flags & SLAB_STORE_USER)
2781 *dbg_userword(cachep, objp) = caller;
2783 if (cachep->flags & SLAB_RED_ZONE) {
2784 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
2785 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
2786 slab_error(cachep, "double free, or memory outside"
2787 " object was overwritten");
2789 "%p: redzone 1:0x%lx, redzone 2:0x%lx\n",
2790 objp, *dbg_redzone1(cachep, objp),
2791 *dbg_redzone2(cachep, objp));
2793 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
2794 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
2796 objp += obj_offset(cachep);
2797 if (cachep->ctor && cachep->flags & SLAB_POISON) {
2798 unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR;
2800 if (!(flags & __GFP_WAIT))
2801 ctor_flags |= SLAB_CTOR_ATOMIC;
2803 cachep->ctor(objp, cachep, ctor_flags);
2808 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
2811 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
2814 struct array_cache *ac;
2817 if (unlikely(current->mempolicy && !in_interrupt())) {
2818 int nid = slab_node(current->mempolicy);
2820 if (nid != numa_node_id())
2821 return __cache_alloc_node(cachep, flags, nid);
2826 ac = cpu_cache_get(cachep);
2827 if (likely(ac->avail)) {
2828 STATS_INC_ALLOCHIT(cachep);
2830 objp = ac->entry[--ac->avail];
2832 STATS_INC_ALLOCMISS(cachep);
2833 objp = cache_alloc_refill(cachep, flags);
2838 static __always_inline void *__cache_alloc(struct kmem_cache *cachep,
2839 gfp_t flags, void *caller)
2841 unsigned long save_flags;
2844 cache_alloc_debugcheck_before(cachep, flags);
2846 local_irq_save(save_flags);
2847 objp = ____cache_alloc(cachep, flags);
2848 local_irq_restore(save_flags);
2849 objp = cache_alloc_debugcheck_after(cachep, flags, objp,
2857 * A interface to enable slab creation on nodeid
2859 static void *__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
2862 struct list_head *entry;
2864 struct kmem_list3 *l3;
2868 l3 = cachep->nodelists[nodeid];
2873 spin_lock(&l3->list_lock);
2874 entry = l3->slabs_partial.next;
2875 if (entry == &l3->slabs_partial) {
2876 l3->free_touched = 1;
2877 entry = l3->slabs_free.next;
2878 if (entry == &l3->slabs_free)
2882 slabp = list_entry(entry, struct slab, list);
2883 check_spinlock_acquired_node(cachep, nodeid);
2884 check_slabp(cachep, slabp);
2886 STATS_INC_NODEALLOCS(cachep);
2887 STATS_INC_ACTIVE(cachep);
2888 STATS_SET_HIGH(cachep);
2890 BUG_ON(slabp->inuse == cachep->num);
2892 obj = slab_get_obj(cachep, slabp, nodeid);
2893 check_slabp(cachep, slabp);
2895 /* move slabp to correct slabp list: */
2896 list_del(&slabp->list);
2898 if (slabp->free == BUFCTL_END)
2899 list_add(&slabp->list, &l3->slabs_full);
2901 list_add(&slabp->list, &l3->slabs_partial);
2903 spin_unlock(&l3->list_lock);
2907 spin_unlock(&l3->list_lock);
2908 x = cache_grow(cachep, flags, nodeid);
2920 * Caller needs to acquire correct kmem_list's list_lock
2922 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
2926 struct kmem_list3 *l3;
2928 for (i = 0; i < nr_objects; i++) {
2929 void *objp = objpp[i];
2932 slabp = virt_to_slab(objp);
2933 l3 = cachep->nodelists[node];
2934 list_del(&slabp->list);
2935 check_spinlock_acquired_node(cachep, node);
2936 check_slabp(cachep, slabp);
2937 slab_put_obj(cachep, slabp, objp, node);
2938 STATS_DEC_ACTIVE(cachep);
2940 check_slabp(cachep, slabp);
2942 /* fixup slab chains */
2943 if (slabp->inuse == 0) {
2944 if (l3->free_objects > l3->free_limit) {
2945 l3->free_objects -= cachep->num;
2946 slab_destroy(cachep, slabp);
2948 list_add(&slabp->list, &l3->slabs_free);
2951 /* Unconditionally move a slab to the end of the
2952 * partial list on free - maximum time for the
2953 * other objects to be freed, too.
2955 list_add_tail(&slabp->list, &l3->slabs_partial);
2960 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
2963 struct kmem_list3 *l3;
2964 int node = numa_node_id();
2966 batchcount = ac->batchcount;
2968 BUG_ON(!batchcount || batchcount > ac->avail);
2971 l3 = cachep->nodelists[node];
2972 spin_lock(&l3->list_lock);
2974 struct array_cache *shared_array = l3->shared;
2975 int max = shared_array->limit - shared_array->avail;
2977 if (batchcount > max)
2979 memcpy(&(shared_array->entry[shared_array->avail]),
2980 ac->entry, sizeof(void *) * batchcount);
2981 shared_array->avail += batchcount;
2986 free_block(cachep, ac->entry, batchcount, node);
2991 struct list_head *p;
2993 p = l3->slabs_free.next;
2994 while (p != &(l3->slabs_free)) {
2997 slabp = list_entry(p, struct slab, list);
2998 BUG_ON(slabp->inuse);
3003 STATS_SET_FREEABLE(cachep, i);
3006 spin_unlock(&l3->list_lock);
3007 ac->avail -= batchcount;
3008 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3012 * Release an obj back to its cache. If the obj has a constructed state, it must
3013 * be in this state _before_ it is released. Called with disabled ints.
3015 static inline void __cache_free(struct kmem_cache *cachep, void *objp)
3017 struct array_cache *ac = cpu_cache_get(cachep);
3020 objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
3022 /* Make sure we are not freeing a object from another
3023 * node to the array cache on this cpu.
3028 slabp = virt_to_slab(objp);
3029 if (unlikely(slabp->nodeid != numa_node_id())) {
3030 struct array_cache *alien = NULL;
3031 int nodeid = slabp->nodeid;
3032 struct kmem_list3 *l3;
3034 l3 = cachep->nodelists[numa_node_id()];
3035 STATS_INC_NODEFREES(cachep);
3036 if (l3->alien && l3->alien[nodeid]) {
3037 alien = l3->alien[nodeid];
3038 spin_lock(&alien->lock);
3039 if (unlikely(alien->avail == alien->limit))
3040 __drain_alien_cache(cachep,
3042 alien->entry[alien->avail++] = objp;
3043 spin_unlock(&alien->lock);
3045 spin_lock(&(cachep->nodelists[nodeid])->
3047 free_block(cachep, &objp, 1, nodeid);
3048 spin_unlock(&(cachep->nodelists[nodeid])->
3055 if (likely(ac->avail < ac->limit)) {
3056 STATS_INC_FREEHIT(cachep);
3057 ac->entry[ac->avail++] = objp;
3060 STATS_INC_FREEMISS(cachep);
3061 cache_flusharray(cachep, ac);
3062 ac->entry[ac->avail++] = objp;
3067 * kmem_cache_alloc - Allocate an object
3068 * @cachep: The cache to allocate from.
3069 * @flags: See kmalloc().
3071 * Allocate an object from this cache. The flags are only relevant
3072 * if the cache has no available objects.
3074 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3076 return __cache_alloc(cachep, flags, __builtin_return_address(0));
3078 EXPORT_SYMBOL(kmem_cache_alloc);
3081 * kmem_ptr_validate - check if an untrusted pointer might
3083 * @cachep: the cache we're checking against
3084 * @ptr: pointer to validate
3086 * This verifies that the untrusted pointer looks sane:
3087 * it is _not_ a guarantee that the pointer is actually
3088 * part of the slab cache in question, but it at least
3089 * validates that the pointer can be dereferenced and
3090 * looks half-way sane.
3092 * Currently only used for dentry validation.
3094 int fastcall kmem_ptr_validate(struct kmem_cache *cachep, void *ptr)
3096 unsigned long addr = (unsigned long)ptr;
3097 unsigned long min_addr = PAGE_OFFSET;
3098 unsigned long align_mask = BYTES_PER_WORD - 1;
3099 unsigned long size = cachep->buffer_size;
3102 if (unlikely(addr < min_addr))
3104 if (unlikely(addr > (unsigned long)high_memory - size))
3106 if (unlikely(addr & align_mask))
3108 if (unlikely(!kern_addr_valid(addr)))
3110 if (unlikely(!kern_addr_valid(addr + size - 1)))
3112 page = virt_to_page(ptr);
3113 if (unlikely(!PageSlab(page)))
3115 if (unlikely(page_get_cache(page) != cachep))
3124 * kmem_cache_alloc_node - Allocate an object on the specified node
3125 * @cachep: The cache to allocate from.
3126 * @flags: See kmalloc().
3127 * @nodeid: node number of the target node.
3129 * Identical to kmem_cache_alloc, except that this function is slow
3130 * and can sleep. And it will allocate memory on the given node, which
3131 * can improve the performance for cpu bound structures.
3132 * New and improved: it will now make sure that the object gets
3133 * put on the correct node list so that there is no false sharing.
3135 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3137 unsigned long save_flags;
3140 cache_alloc_debugcheck_before(cachep, flags);
3141 local_irq_save(save_flags);
3143 if (nodeid == -1 || nodeid == numa_node_id() ||
3144 !cachep->nodelists[nodeid])
3145 ptr = ____cache_alloc(cachep, flags);
3147 ptr = __cache_alloc_node(cachep, flags, nodeid);
3148 local_irq_restore(save_flags);
3150 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr,
3151 __builtin_return_address(0));
3155 EXPORT_SYMBOL(kmem_cache_alloc_node);
3157 void *kmalloc_node(size_t size, gfp_t flags, int node)
3159 struct kmem_cache *cachep;
3161 cachep = kmem_find_general_cachep(size, flags);
3162 if (unlikely(cachep == NULL))
3164 return kmem_cache_alloc_node(cachep, flags, node);
3166 EXPORT_SYMBOL(kmalloc_node);
3170 * kmalloc - allocate memory
3171 * @size: how many bytes of memory are required.
3172 * @flags: the type of memory to allocate.
3174 * kmalloc is the normal method of allocating memory
3177 * The @flags argument may be one of:
3179 * %GFP_USER - Allocate memory on behalf of user. May sleep.
3181 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
3183 * %GFP_ATOMIC - Allocation will not sleep. Use inside interrupt handlers.
3185 * Additionally, the %GFP_DMA flag may be set to indicate the memory
3186 * must be suitable for DMA. This can mean different things on different
3187 * platforms. For example, on i386, it means that the memory must come
3188 * from the first 16MB.
3190 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3193 struct kmem_cache *cachep;
3195 /* If you want to save a few bytes .text space: replace
3197 * Then kmalloc uses the uninlined functions instead of the inline
3200 cachep = __find_general_cachep(size, flags);
3201 if (unlikely(cachep == NULL))
3203 return __cache_alloc(cachep, flags, caller);
3206 #ifndef CONFIG_DEBUG_SLAB
3208 void *__kmalloc(size_t size, gfp_t flags)
3210 return __do_kmalloc(size, flags, NULL);
3212 EXPORT_SYMBOL(__kmalloc);
3216 void *__kmalloc_track_caller(size_t size, gfp_t flags, void *caller)
3218 return __do_kmalloc(size, flags, caller);
3220 EXPORT_SYMBOL(__kmalloc_track_caller);
3226 * __alloc_percpu - allocate one copy of the object for every present
3227 * cpu in the system, zeroing them.
3228 * Objects should be dereferenced using the per_cpu_ptr macro only.
3230 * @size: how many bytes of memory are required.
3232 void *__alloc_percpu(size_t size)
3235 struct percpu_data *pdata = kmalloc(sizeof(*pdata), GFP_KERNEL);
3241 * Cannot use for_each_online_cpu since a cpu may come online
3242 * and we have no way of figuring out how to fix the array
3243 * that we have allocated then....
3246 int node = cpu_to_node(i);
3248 if (node_online(node))
3249 pdata->ptrs[i] = kmalloc_node(size, GFP_KERNEL, node);
3251 pdata->ptrs[i] = kmalloc(size, GFP_KERNEL);
3253 if (!pdata->ptrs[i])
3255 memset(pdata->ptrs[i], 0, size);
3258 /* Catch derefs w/o wrappers */
3259 return (void *)(~(unsigned long)pdata);
3263 if (!cpu_possible(i))
3265 kfree(pdata->ptrs[i]);
3270 EXPORT_SYMBOL(__alloc_percpu);
3274 * kmem_cache_free - Deallocate an object
3275 * @cachep: The cache the allocation was from.
3276 * @objp: The previously allocated object.
3278 * Free an object which was previously allocated from this
3281 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3283 unsigned long flags;
3285 local_irq_save(flags);
3286 __cache_free(cachep, objp);
3287 local_irq_restore(flags);
3289 EXPORT_SYMBOL(kmem_cache_free);
3292 * kfree - free previously allocated memory
3293 * @objp: pointer returned by kmalloc.
3295 * If @objp is NULL, no operation is performed.
3297 * Don't free memory not originally allocated by kmalloc()
3298 * or you will run into trouble.
3300 void kfree(const void *objp)
3302 struct kmem_cache *c;
3303 unsigned long flags;
3305 if (unlikely(!objp))
3307 local_irq_save(flags);
3308 kfree_debugcheck(objp);
3309 c = virt_to_cache(objp);
3310 mutex_debug_check_no_locks_freed(objp, obj_size(c));
3311 __cache_free(c, (void *)objp);
3312 local_irq_restore(flags);
3314 EXPORT_SYMBOL(kfree);
3318 * free_percpu - free previously allocated percpu memory
3319 * @objp: pointer returned by alloc_percpu.
3321 * Don't free memory not originally allocated by alloc_percpu()
3322 * The complemented objp is to check for that.
3324 void free_percpu(const void *objp)
3327 struct percpu_data *p = (struct percpu_data *)(~(unsigned long)objp);
3330 * We allocate for all cpus so we cannot use for online cpu here.
3336 EXPORT_SYMBOL(free_percpu);
3339 unsigned int kmem_cache_size(struct kmem_cache *cachep)
3341 return obj_size(cachep);
3343 EXPORT_SYMBOL(kmem_cache_size);
3345 const char *kmem_cache_name(struct kmem_cache *cachep)
3347 return cachep->name;
3349 EXPORT_SYMBOL_GPL(kmem_cache_name);
3352 * This initializes kmem_list3 for all nodes.
3354 static int alloc_kmemlist(struct kmem_cache *cachep)
3357 struct kmem_list3 *l3;
3360 for_each_online_node(node) {
3361 struct array_cache *nc = NULL, *new;
3362 struct array_cache **new_alien = NULL;
3364 new_alien = alloc_alien_cache(node, cachep->limit);
3368 new = alloc_arraycache(node, cachep->shared*cachep->batchcount,
3372 l3 = cachep->nodelists[node];
3374 spin_lock_irq(&l3->list_lock);
3376 nc = cachep->nodelists[node]->shared;
3378 free_block(cachep, nc->entry, nc->avail, node);
3381 if (!cachep->nodelists[node]->alien) {
3382 l3->alien = new_alien;
3385 l3->free_limit = (1 + nr_cpus_node(node)) *
3386 cachep->batchcount + cachep->num;
3387 spin_unlock_irq(&l3->list_lock);
3389 free_alien_cache(new_alien);
3392 l3 = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, node);
3396 kmem_list3_init(l3);
3397 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
3398 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
3400 l3->alien = new_alien;
3401 l3->free_limit = (1 + nr_cpus_node(node)) *
3402 cachep->batchcount + cachep->num;
3403 cachep->nodelists[node] = l3;
3411 struct ccupdate_struct {
3412 struct kmem_cache *cachep;
3413 struct array_cache *new[NR_CPUS];
3416 static void do_ccupdate_local(void *info)
3418 struct ccupdate_struct *new = info;
3419 struct array_cache *old;
3422 old = cpu_cache_get(new->cachep);
3424 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
3425 new->new[smp_processor_id()] = old;
3428 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3429 int batchcount, int shared)
3431 struct ccupdate_struct new;
3434 memset(&new.new, 0, sizeof(new.new));
3435 for_each_online_cpu(i) {
3436 new.new[i] = alloc_arraycache(cpu_to_node(i), limit,
3439 for (i--; i >= 0; i--)
3444 new.cachep = cachep;
3446 smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
3449 spin_lock(&cachep->spinlock);
3450 cachep->batchcount = batchcount;
3451 cachep->limit = limit;
3452 cachep->shared = shared;
3453 spin_unlock(&cachep->spinlock);
3455 for_each_online_cpu(i) {
3456 struct array_cache *ccold = new.new[i];
3459 spin_lock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3460 free_block(cachep, ccold->entry, ccold->avail, cpu_to_node(i));
3461 spin_unlock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3465 err = alloc_kmemlist(cachep);
3467 printk(KERN_ERR "alloc_kmemlist failed for %s, error %d.\n",
3468 cachep->name, -err);
3474 static void enable_cpucache(struct kmem_cache *cachep)
3480 * The head array serves three purposes:
3481 * - create a LIFO ordering, i.e. return objects that are cache-warm
3482 * - reduce the number of spinlock operations.
3483 * - reduce the number of linked list operations on the slab and
3484 * bufctl chains: array operations are cheaper.
3485 * The numbers are guessed, we should auto-tune as described by
3488 if (cachep->buffer_size > 131072)
3490 else if (cachep->buffer_size > PAGE_SIZE)
3492 else if (cachep->buffer_size > 1024)
3494 else if (cachep->buffer_size > 256)
3500 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3501 * allocation behaviour: Most allocs on one cpu, most free operations
3502 * on another cpu. For these cases, an efficient object passing between
3503 * cpus is necessary. This is provided by a shared array. The array
3504 * replaces Bonwick's magazine layer.
3505 * On uniprocessor, it's functionally equivalent (but less efficient)
3506 * to a larger limit. Thus disabled by default.
3510 if (cachep->buffer_size <= PAGE_SIZE)
3516 * With debugging enabled, large batchcount lead to excessively long
3517 * periods with disabled local interrupts. Limit the batchcount
3522 err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared);
3524 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
3525 cachep->name, -err);
3528 static void drain_array_locked(struct kmem_cache *cachep,
3529 struct array_cache *ac, int force, int node)
3533 check_spinlock_acquired_node(cachep, node);
3534 if (ac->touched && !force) {
3536 } else if (ac->avail) {
3537 tofree = force ? ac->avail : (ac->limit + 4) / 5;
3538 if (tofree > ac->avail)
3539 tofree = (ac->avail + 1) / 2;
3540 free_block(cachep, ac->entry, tofree, node);
3541 ac->avail -= tofree;
3542 memmove(ac->entry, &(ac->entry[tofree]),
3543 sizeof(void *) * ac->avail);
3548 * cache_reap - Reclaim memory from caches.
3549 * @unused: unused parameter
3551 * Called from workqueue/eventd every few seconds.
3553 * - clear the per-cpu caches for this CPU.
3554 * - return freeable pages to the main free memory pool.
3556 * If we cannot acquire the cache chain mutex then just give up - we'll try
3557 * again on the next iteration.
3559 static void cache_reap(void *unused)
3561 struct list_head *walk;
3562 struct kmem_list3 *l3;
3564 if (!mutex_trylock(&cache_chain_mutex)) {
3565 /* Give up. Setup the next iteration. */
3566 schedule_delayed_work(&__get_cpu_var(reap_work),
3571 list_for_each(walk, &cache_chain) {
3572 struct kmem_cache *searchp;
3573 struct list_head *p;
3577 searchp = list_entry(walk, struct kmem_cache, next);
3579 if (searchp->flags & SLAB_NO_REAP)
3584 l3 = searchp->nodelists[numa_node_id()];
3585 reap_alien(searchp, l3);
3586 spin_lock_irq(&l3->list_lock);
3588 drain_array_locked(searchp, cpu_cache_get(searchp), 0,
3591 if (time_after(l3->next_reap, jiffies))
3594 l3->next_reap = jiffies + REAPTIMEOUT_LIST3;
3597 drain_array_locked(searchp, l3->shared, 0,
3600 if (l3->free_touched) {
3601 l3->free_touched = 0;
3605 tofree = (l3->free_limit + 5 * searchp->num - 1) /
3608 p = l3->slabs_free.next;
3609 if (p == &(l3->slabs_free))
3612 slabp = list_entry(p, struct slab, list);
3613 BUG_ON(slabp->inuse);
3614 list_del(&slabp->list);
3615 STATS_INC_REAPED(searchp);
3618 * Safe to drop the lock. The slab is no longer linked
3619 * to the cache. searchp cannot disappear, we hold
3622 l3->free_objects -= searchp->num;
3623 spin_unlock_irq(&l3->list_lock);
3624 slab_destroy(searchp, slabp);
3625 spin_lock_irq(&l3->list_lock);
3626 } while (--tofree > 0);
3628 spin_unlock_irq(&l3->list_lock);
3633 mutex_unlock(&cache_chain_mutex);
3635 /* Set up the next iteration */
3636 schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC);
3639 #ifdef CONFIG_PROC_FS
3641 static void print_slabinfo_header(struct seq_file *m)
3644 * Output format version, so at least we can change it
3645 * without _too_ many complaints.
3648 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
3650 seq_puts(m, "slabinfo - version: 2.1\n");
3652 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
3653 "<objperslab> <pagesperslab>");
3654 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
3655 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
3657 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
3658 "<error> <maxfreeable> <nodeallocs> <remotefrees>");
3659 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
3664 static void *s_start(struct seq_file *m, loff_t *pos)
3667 struct list_head *p;
3669 mutex_lock(&cache_chain_mutex);
3671 print_slabinfo_header(m);
3672 p = cache_chain.next;
3675 if (p == &cache_chain)
3678 return list_entry(p, struct kmem_cache, next);
3681 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
3683 struct kmem_cache *cachep = p;
3685 return cachep->next.next == &cache_chain ?
3686 NULL : list_entry(cachep->next.next, struct kmem_cache, next);
3689 static void s_stop(struct seq_file *m, void *p)
3691 mutex_unlock(&cache_chain_mutex);
3694 static int s_show(struct seq_file *m, void *p)
3696 struct kmem_cache *cachep = p;
3697 struct list_head *q;
3699 unsigned long active_objs;
3700 unsigned long num_objs;
3701 unsigned long active_slabs = 0;
3702 unsigned long num_slabs, free_objects = 0, shared_avail = 0;
3706 struct kmem_list3 *l3;
3708 spin_lock(&cachep->spinlock);
3711 for_each_online_node(node) {
3712 l3 = cachep->nodelists[node];
3717 spin_lock_irq(&l3->list_lock);
3719 list_for_each(q, &l3->slabs_full) {
3720 slabp = list_entry(q, struct slab, list);
3721 if (slabp->inuse != cachep->num && !error)
3722 error = "slabs_full accounting error";
3723 active_objs += cachep->num;
3726 list_for_each(q, &l3->slabs_partial) {
3727 slabp = list_entry(q, struct slab, list);
3728 if (slabp->inuse == cachep->num && !error)
3729 error = "slabs_partial inuse accounting error";
3730 if (!slabp->inuse && !error)
3731 error = "slabs_partial/inuse accounting error";
3732 active_objs += slabp->inuse;
3735 list_for_each(q, &l3->slabs_free) {
3736 slabp = list_entry(q, struct slab, list);
3737 if (slabp->inuse && !error)
3738 error = "slabs_free/inuse accounting error";
3741 free_objects += l3->free_objects;
3743 shared_avail += l3->shared->avail;
3745 spin_unlock_irq(&l3->list_lock);
3747 num_slabs += active_slabs;
3748 num_objs = num_slabs * cachep->num;
3749 if (num_objs - active_objs != free_objects && !error)
3750 error = "free_objects accounting error";
3752 name = cachep->name;
3754 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
3756 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
3757 name, active_objs, num_objs, cachep->buffer_size,
3758 cachep->num, (1 << cachep->gfporder));
3759 seq_printf(m, " : tunables %4u %4u %4u",
3760 cachep->limit, cachep->batchcount, cachep->shared);
3761 seq_printf(m, " : slabdata %6lu %6lu %6lu",
3762 active_slabs, num_slabs, shared_avail);
3765 unsigned long high = cachep->high_mark;
3766 unsigned long allocs = cachep->num_allocations;
3767 unsigned long grown = cachep->grown;
3768 unsigned long reaped = cachep->reaped;
3769 unsigned long errors = cachep->errors;
3770 unsigned long max_freeable = cachep->max_freeable;
3771 unsigned long node_allocs = cachep->node_allocs;
3772 unsigned long node_frees = cachep->node_frees;
3774 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu \
3775 %4lu %4lu %4lu %4lu", allocs, high, grown,
3776 reaped, errors, max_freeable, node_allocs,
3781 unsigned long allochit = atomic_read(&cachep->allochit);
3782 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
3783 unsigned long freehit = atomic_read(&cachep->freehit);
3784 unsigned long freemiss = atomic_read(&cachep->freemiss);
3786 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
3787 allochit, allocmiss, freehit, freemiss);
3791 spin_unlock(&cachep->spinlock);
3796 * slabinfo_op - iterator that generates /proc/slabinfo
3805 * num-pages-per-slab
3806 * + further values on SMP and with statistics enabled
3809 struct seq_operations slabinfo_op = {
3816 #define MAX_SLABINFO_WRITE 128
3818 * slabinfo_write - Tuning for the slab allocator
3820 * @buffer: user buffer
3821 * @count: data length
3824 ssize_t slabinfo_write(struct file *file, const char __user * buffer,
3825 size_t count, loff_t *ppos)
3827 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
3828 int limit, batchcount, shared, res;
3829 struct list_head *p;
3831 if (count > MAX_SLABINFO_WRITE)
3833 if (copy_from_user(&kbuf, buffer, count))
3835 kbuf[MAX_SLABINFO_WRITE] = '\0';
3837 tmp = strchr(kbuf, ' ');
3842 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
3845 /* Find the cache in the chain of caches. */
3846 mutex_lock(&cache_chain_mutex);
3848 list_for_each(p, &cache_chain) {
3849 struct kmem_cache *cachep;
3851 cachep = list_entry(p, struct kmem_cache, next);
3852 if (!strcmp(cachep->name, kbuf)) {
3853 if (limit < 1 || batchcount < 1 ||
3854 batchcount > limit || shared < 0) {
3857 res = do_tune_cpucache(cachep, limit,
3858 batchcount, shared);
3863 mutex_unlock(&cache_chain_mutex);
3871 * ksize - get the actual amount of memory allocated for a given object
3872 * @objp: Pointer to the object
3874 * kmalloc may internally round up allocations and return more memory
3875 * than requested. ksize() can be used to determine the actual amount of
3876 * memory allocated. The caller may use this additional memory, even though
3877 * a smaller amount of memory was initially specified with the kmalloc call.
3878 * The caller must guarantee that objp points to a valid object previously
3879 * allocated with either kmalloc() or kmem_cache_alloc(). The object
3880 * must not be freed during the duration of the call.
3882 unsigned int ksize(const void *objp)
3884 if (unlikely(objp == NULL))
3887 return obj_size(virt_to_cache(objp));