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/poison.h>
93 #include <linux/swap.h>
94 #include <linux/cache.h>
95 #include <linux/interrupt.h>
96 #include <linux/init.h>
97 #include <linux/compiler.h>
98 #include <linux/cpuset.h>
99 #include <linux/seq_file.h>
100 #include <linux/notifier.h>
101 #include <linux/kallsyms.h>
102 #include <linux/cpu.h>
103 #include <linux/sysctl.h>
104 #include <linux/module.h>
105 #include <linux/rcupdate.h>
106 #include <linux/string.h>
107 #include <linux/nodemask.h>
108 #include <linux/mempolicy.h>
109 #include <linux/mutex.h>
110 #include <linux/rtmutex.h>
112 #include <asm/uaccess.h>
113 #include <asm/cacheflush.h>
114 #include <asm/tlbflush.h>
115 #include <asm/page.h>
118 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
119 * SLAB_RED_ZONE & SLAB_POISON.
120 * 0 for faster, smaller code (especially in the critical paths).
122 * STATS - 1 to collect stats for /proc/slabinfo.
123 * 0 for faster, smaller code (especially in the critical paths).
125 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
128 #ifdef CONFIG_DEBUG_SLAB
131 #define FORCED_DEBUG 1
135 #define FORCED_DEBUG 0
138 /* Shouldn't this be in a header file somewhere? */
139 #define BYTES_PER_WORD sizeof(void *)
141 #ifndef cache_line_size
142 #define cache_line_size() L1_CACHE_BYTES
145 #ifndef ARCH_KMALLOC_MINALIGN
147 * Enforce a minimum alignment for the kmalloc caches.
148 * Usually, the kmalloc caches are cache_line_size() aligned, except when
149 * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
150 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
151 * alignment larger than BYTES_PER_WORD. ARCH_KMALLOC_MINALIGN allows that.
152 * Note that this flag disables some debug features.
154 #define ARCH_KMALLOC_MINALIGN 0
157 #ifndef ARCH_SLAB_MINALIGN
159 * Enforce a minimum alignment for all caches.
160 * Intended for archs that get misalignment faults even for BYTES_PER_WORD
161 * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
162 * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
163 * some debug features.
165 #define ARCH_SLAB_MINALIGN 0
168 #ifndef ARCH_KMALLOC_FLAGS
169 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
172 /* Legal flag mask for kmem_cache_create(). */
174 # define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
175 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
177 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \
178 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
179 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD)
181 # define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
182 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \
183 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
184 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD)
190 * Bufctl's are used for linking objs within a slab
193 * This implementation relies on "struct page" for locating the cache &
194 * slab an object belongs to.
195 * This allows the bufctl structure to be small (one int), but limits
196 * the number of objects a slab (not a cache) can contain when off-slab
197 * bufctls are used. The limit is the size of the largest general cache
198 * that does not use off-slab slabs.
199 * For 32bit archs with 4 kB pages, is this 56.
200 * This is not serious, as it is only for large objects, when it is unwise
201 * to have too many per slab.
202 * Note: This limit can be raised by introducing a general cache whose size
203 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
206 typedef unsigned int kmem_bufctl_t;
207 #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
208 #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
209 #define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2)
210 #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3)
215 * Manages the objs in a slab. Placed either at the beginning of mem allocated
216 * for a slab, or allocated from an general cache.
217 * Slabs are chained into three list: fully used, partial, fully free slabs.
220 struct list_head list;
221 unsigned long colouroff;
222 void *s_mem; /* including colour offset */
223 unsigned int inuse; /* num of objs active in slab */
225 unsigned short nodeid;
231 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
232 * arrange for kmem_freepages to be called via RCU. This is useful if
233 * we need to approach a kernel structure obliquely, from its address
234 * obtained without the usual locking. We can lock the structure to
235 * stabilize it and check it's still at the given address, only if we
236 * can be sure that the memory has not been meanwhile reused for some
237 * other kind of object (which our subsystem's lock might corrupt).
239 * rcu_read_lock before reading the address, then rcu_read_unlock after
240 * taking the spinlock within the structure expected at that address.
242 * We assume struct slab_rcu can overlay struct slab when destroying.
245 struct rcu_head head;
246 struct kmem_cache *cachep;
254 * - LIFO ordering, to hand out cache-warm objects from _alloc
255 * - reduce the number of linked list operations
256 * - reduce spinlock operations
258 * The limit is stored in the per-cpu structure to reduce the data cache
265 unsigned int batchcount;
266 unsigned int touched;
269 * Must have this definition in here for the proper
270 * alignment of array_cache. Also simplifies accessing
272 * [0] is for gcc 2.95. It should really be [].
277 * bootstrap: The caches do not work without cpuarrays anymore, but the
278 * cpuarrays are allocated from the generic caches...
280 #define BOOT_CPUCACHE_ENTRIES 1
281 struct arraycache_init {
282 struct array_cache cache;
283 void *entries[BOOT_CPUCACHE_ENTRIES];
287 * The slab lists for all objects.
290 struct list_head slabs_partial; /* partial list first, better asm code */
291 struct list_head slabs_full;
292 struct list_head slabs_free;
293 unsigned long free_objects;
294 unsigned int free_limit;
295 unsigned int colour_next; /* Per-node cache coloring */
296 spinlock_t list_lock;
297 struct array_cache *shared; /* shared per node */
298 struct array_cache **alien; /* on other nodes */
299 unsigned long next_reap; /* updated without locking */
300 int free_touched; /* updated without locking */
304 * Need this for bootstrapping a per node allocator.
306 #define NUM_INIT_LISTS (2 * MAX_NUMNODES + 1)
307 struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
308 #define CACHE_CACHE 0
310 #define SIZE_L3 (1 + MAX_NUMNODES)
312 static int drain_freelist(struct kmem_cache *cache,
313 struct kmem_list3 *l3, int tofree);
314 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
316 static void enable_cpucache(struct kmem_cache *cachep);
317 static void cache_reap(void *unused);
320 * This function must be completely optimized away if a constant is passed to
321 * it. Mostly the same as what is in linux/slab.h except it returns an index.
323 static __always_inline int index_of(const size_t size)
325 extern void __bad_size(void);
327 if (__builtin_constant_p(size)) {
335 #include "linux/kmalloc_sizes.h"
343 static int slab_early_init = 1;
345 #define INDEX_AC index_of(sizeof(struct arraycache_init))
346 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
348 static void kmem_list3_init(struct kmem_list3 *parent)
350 INIT_LIST_HEAD(&parent->slabs_full);
351 INIT_LIST_HEAD(&parent->slabs_partial);
352 INIT_LIST_HEAD(&parent->slabs_free);
353 parent->shared = NULL;
354 parent->alien = NULL;
355 parent->colour_next = 0;
356 spin_lock_init(&parent->list_lock);
357 parent->free_objects = 0;
358 parent->free_touched = 0;
361 #define MAKE_LIST(cachep, listp, slab, nodeid) \
363 INIT_LIST_HEAD(listp); \
364 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
367 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
369 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
370 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
371 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
381 /* 1) per-cpu data, touched during every alloc/free */
382 struct array_cache *array[NR_CPUS];
383 /* 2) Cache tunables. Protected by cache_chain_mutex */
384 unsigned int batchcount;
388 unsigned int buffer_size;
389 /* 3) touched by every alloc & free from the backend */
390 struct kmem_list3 *nodelists[MAX_NUMNODES];
392 unsigned int flags; /* constant flags */
393 unsigned int num; /* # of objs per slab */
395 /* 4) cache_grow/shrink */
396 /* order of pgs per slab (2^n) */
397 unsigned int gfporder;
399 /* force GFP flags, e.g. GFP_DMA */
402 size_t colour; /* cache colouring range */
403 unsigned int colour_off; /* colour offset */
404 struct kmem_cache *slabp_cache;
405 unsigned int slab_size;
406 unsigned int dflags; /* dynamic flags */
408 /* constructor func */
409 void (*ctor) (void *, struct kmem_cache *, unsigned long);
411 /* de-constructor func */
412 void (*dtor) (void *, struct kmem_cache *, unsigned long);
414 /* 5) cache creation/removal */
416 struct list_head next;
420 unsigned long num_active;
421 unsigned long num_allocations;
422 unsigned long high_mark;
424 unsigned long reaped;
425 unsigned long errors;
426 unsigned long max_freeable;
427 unsigned long node_allocs;
428 unsigned long node_frees;
429 unsigned long node_overflow;
437 * If debugging is enabled, then the allocator can add additional
438 * fields and/or padding to every object. buffer_size contains the total
439 * object size including these internal fields, the following two
440 * variables contain the offset to the user object and its size.
447 #define CFLGS_OFF_SLAB (0x80000000UL)
448 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
450 #define BATCHREFILL_LIMIT 16
452 * Optimization question: fewer reaps means less probability for unnessary
453 * cpucache drain/refill cycles.
455 * OTOH the cpuarrays can contain lots of objects,
456 * which could lock up otherwise freeable slabs.
458 #define REAPTIMEOUT_CPUC (2*HZ)
459 #define REAPTIMEOUT_LIST3 (4*HZ)
462 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
463 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
464 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
465 #define STATS_INC_GROWN(x) ((x)->grown++)
466 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
467 #define STATS_SET_HIGH(x) \
469 if ((x)->num_active > (x)->high_mark) \
470 (x)->high_mark = (x)->num_active; \
472 #define STATS_INC_ERR(x) ((x)->errors++)
473 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
474 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
475 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
476 #define STATS_SET_FREEABLE(x, i) \
478 if ((x)->max_freeable < i) \
479 (x)->max_freeable = i; \
481 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
482 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
483 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
484 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
486 #define STATS_INC_ACTIVE(x) do { } while (0)
487 #define STATS_DEC_ACTIVE(x) do { } while (0)
488 #define STATS_INC_ALLOCED(x) do { } while (0)
489 #define STATS_INC_GROWN(x) do { } while (0)
490 #define STATS_ADD_REAPED(x,y) do { } while (0)
491 #define STATS_SET_HIGH(x) do { } while (0)
492 #define STATS_INC_ERR(x) do { } while (0)
493 #define STATS_INC_NODEALLOCS(x) do { } while (0)
494 #define STATS_INC_NODEFREES(x) do { } while (0)
495 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
496 #define STATS_SET_FREEABLE(x, i) do { } while (0)
497 #define STATS_INC_ALLOCHIT(x) do { } while (0)
498 #define STATS_INC_ALLOCMISS(x) do { } while (0)
499 #define STATS_INC_FREEHIT(x) do { } while (0)
500 #define STATS_INC_FREEMISS(x) do { } while (0)
506 * memory layout of objects:
508 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
509 * the end of an object is aligned with the end of the real
510 * allocation. Catches writes behind the end of the allocation.
511 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
513 * cachep->obj_offset: The real object.
514 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
515 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
516 * [BYTES_PER_WORD long]
518 static int obj_offset(struct kmem_cache *cachep)
520 return cachep->obj_offset;
523 static int obj_size(struct kmem_cache *cachep)
525 return cachep->obj_size;
528 static unsigned long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
530 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
531 return (unsigned long*) (objp+obj_offset(cachep)-BYTES_PER_WORD);
534 static unsigned long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
536 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
537 if (cachep->flags & SLAB_STORE_USER)
538 return (unsigned long *)(objp + cachep->buffer_size -
540 return (unsigned long *)(objp + cachep->buffer_size - BYTES_PER_WORD);
543 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
545 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
546 return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
551 #define obj_offset(x) 0
552 #define obj_size(cachep) (cachep->buffer_size)
553 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long *)NULL;})
554 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long *)NULL;})
555 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
560 * Maximum size of an obj (in 2^order pages) and absolute limit for the gfp
563 #if defined(CONFIG_LARGE_ALLOCS)
564 #define MAX_OBJ_ORDER 13 /* up to 32Mb */
565 #define MAX_GFP_ORDER 13 /* up to 32Mb */
566 #elif defined(CONFIG_MMU)
567 #define MAX_OBJ_ORDER 5 /* 32 pages */
568 #define MAX_GFP_ORDER 5 /* 32 pages */
570 #define MAX_OBJ_ORDER 8 /* up to 1Mb */
571 #define MAX_GFP_ORDER 8 /* up to 1Mb */
575 * Do not go above this order unless 0 objects fit into the slab.
577 #define BREAK_GFP_ORDER_HI 1
578 #define BREAK_GFP_ORDER_LO 0
579 static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
582 * Functions for storing/retrieving the cachep and or slab from the page
583 * allocator. These are used to find the slab an obj belongs to. With kfree(),
584 * these are used to find the cache which an obj belongs to.
586 static inline void page_set_cache(struct page *page, struct kmem_cache *cache)
588 page->lru.next = (struct list_head *)cache;
591 static inline struct kmem_cache *page_get_cache(struct page *page)
593 if (unlikely(PageCompound(page)))
594 page = (struct page *)page_private(page);
595 BUG_ON(!PageSlab(page));
596 return (struct kmem_cache *)page->lru.next;
599 static inline void page_set_slab(struct page *page, struct slab *slab)
601 page->lru.prev = (struct list_head *)slab;
604 static inline struct slab *page_get_slab(struct page *page)
606 if (unlikely(PageCompound(page)))
607 page = (struct page *)page_private(page);
608 BUG_ON(!PageSlab(page));
609 return (struct slab *)page->lru.prev;
612 static inline struct kmem_cache *virt_to_cache(const void *obj)
614 struct page *page = virt_to_page(obj);
615 return page_get_cache(page);
618 static inline struct slab *virt_to_slab(const void *obj)
620 struct page *page = virt_to_page(obj);
621 return page_get_slab(page);
624 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
627 return slab->s_mem + cache->buffer_size * idx;
630 static inline unsigned int obj_to_index(struct kmem_cache *cache,
631 struct slab *slab, void *obj)
633 return (unsigned)(obj - slab->s_mem) / cache->buffer_size;
637 * These are the default caches for kmalloc. Custom caches can have other sizes.
639 struct cache_sizes malloc_sizes[] = {
640 #define CACHE(x) { .cs_size = (x) },
641 #include <linux/kmalloc_sizes.h>
645 EXPORT_SYMBOL(malloc_sizes);
647 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
653 static struct cache_names __initdata cache_names[] = {
654 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
655 #include <linux/kmalloc_sizes.h>
660 static struct arraycache_init initarray_cache __initdata =
661 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
662 static struct arraycache_init initarray_generic =
663 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
665 /* internal cache of cache description objs */
666 static struct kmem_cache cache_cache = {
668 .limit = BOOT_CPUCACHE_ENTRIES,
670 .buffer_size = sizeof(struct kmem_cache),
671 .name = "kmem_cache",
673 .obj_size = sizeof(struct kmem_cache),
677 #ifdef CONFIG_LOCKDEP
680 * Slab sometimes uses the kmalloc slabs to store the slab headers
681 * for other slabs "off slab".
682 * The locking for this is tricky in that it nests within the locks
683 * of all other slabs in a few places; to deal with this special
684 * locking we put on-slab caches into a separate lock-class.
686 static struct lock_class_key on_slab_key;
688 static inline void init_lock_keys(struct cache_sizes *s)
692 for (q = 0; q < MAX_NUMNODES; q++) {
693 if (!s->cs_cachep->nodelists[q] || OFF_SLAB(s->cs_cachep))
695 lockdep_set_class(&s->cs_cachep->nodelists[q]->list_lock,
701 static inline void init_lock_keys(struct cache_sizes *s)
708 /* Guard access to the cache-chain. */
709 static DEFINE_MUTEX(cache_chain_mutex);
710 static struct list_head cache_chain;
713 * vm_enough_memory() looks at this to determine how many slab-allocated pages
714 * are possibly freeable under pressure
716 * SLAB_RECLAIM_ACCOUNT turns this on per-slab
718 atomic_t slab_reclaim_pages;
721 * chicken and egg problem: delay the per-cpu array allocation
722 * until the general caches are up.
732 * used by boot code to determine if it can use slab based allocator
734 int slab_is_available(void)
736 return g_cpucache_up == FULL;
739 static DEFINE_PER_CPU(struct work_struct, reap_work);
741 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
743 return cachep->array[smp_processor_id()];
746 static inline struct kmem_cache *__find_general_cachep(size_t size,
749 struct cache_sizes *csizep = malloc_sizes;
752 /* This happens if someone tries to call
753 * kmem_cache_create(), or __kmalloc(), before
754 * the generic caches are initialized.
756 BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
758 while (size > csizep->cs_size)
762 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
763 * has cs_{dma,}cachep==NULL. Thus no special case
764 * for large kmalloc calls required.
766 if (unlikely(gfpflags & GFP_DMA))
767 return csizep->cs_dmacachep;
768 return csizep->cs_cachep;
771 static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
773 return __find_general_cachep(size, gfpflags);
776 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
778 return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
782 * Calculate the number of objects and left-over bytes for a given buffer size.
784 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
785 size_t align, int flags, size_t *left_over,
790 size_t slab_size = PAGE_SIZE << gfporder;
793 * The slab management structure can be either off the slab or
794 * on it. For the latter case, the memory allocated for a
798 * - One kmem_bufctl_t for each object
799 * - Padding to respect alignment of @align
800 * - @buffer_size bytes for each object
802 * If the slab management structure is off the slab, then the
803 * alignment will already be calculated into the size. Because
804 * the slabs are all pages aligned, the objects will be at the
805 * correct alignment when allocated.
807 if (flags & CFLGS_OFF_SLAB) {
809 nr_objs = slab_size / buffer_size;
811 if (nr_objs > SLAB_LIMIT)
812 nr_objs = SLAB_LIMIT;
815 * Ignore padding for the initial guess. The padding
816 * is at most @align-1 bytes, and @buffer_size is at
817 * least @align. In the worst case, this result will
818 * be one greater than the number of objects that fit
819 * into the memory allocation when taking the padding
822 nr_objs = (slab_size - sizeof(struct slab)) /
823 (buffer_size + sizeof(kmem_bufctl_t));
826 * This calculated number will be either the right
827 * amount, or one greater than what we want.
829 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
833 if (nr_objs > SLAB_LIMIT)
834 nr_objs = SLAB_LIMIT;
836 mgmt_size = slab_mgmt_size(nr_objs, align);
839 *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
842 #define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg)
844 static void __slab_error(const char *function, struct kmem_cache *cachep,
847 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
848 function, cachep->name, msg);
854 * Special reaping functions for NUMA systems called from cache_reap().
855 * These take care of doing round robin flushing of alien caches (containing
856 * objects freed on different nodes from which they were allocated) and the
857 * flushing of remote pcps by calling drain_node_pages.
859 static DEFINE_PER_CPU(unsigned long, reap_node);
861 static void init_reap_node(int cpu)
865 node = next_node(cpu_to_node(cpu), node_online_map);
866 if (node == MAX_NUMNODES)
867 node = first_node(node_online_map);
869 __get_cpu_var(reap_node) = node;
872 static void next_reap_node(void)
874 int node = __get_cpu_var(reap_node);
877 * Also drain per cpu pages on remote zones
879 if (node != numa_node_id())
880 drain_node_pages(node);
882 node = next_node(node, node_online_map);
883 if (unlikely(node >= MAX_NUMNODES))
884 node = first_node(node_online_map);
885 __get_cpu_var(reap_node) = node;
889 #define init_reap_node(cpu) do { } while (0)
890 #define next_reap_node(void) do { } while (0)
894 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
895 * via the workqueue/eventd.
896 * Add the CPU number into the expiration time to minimize the possibility of
897 * the CPUs getting into lockstep and contending for the global cache chain
900 static void __devinit start_cpu_timer(int cpu)
902 struct work_struct *reap_work = &per_cpu(reap_work, cpu);
905 * When this gets called from do_initcalls via cpucache_init(),
906 * init_workqueues() has already run, so keventd will be setup
909 if (keventd_up() && reap_work->func == NULL) {
911 INIT_WORK(reap_work, cache_reap, NULL);
912 schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu);
916 static struct array_cache *alloc_arraycache(int node, int entries,
919 int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
920 struct array_cache *nc = NULL;
922 nc = kmalloc_node(memsize, GFP_KERNEL, node);
926 nc->batchcount = batchcount;
928 spin_lock_init(&nc->lock);
934 * Transfer objects in one arraycache to another.
935 * Locking must be handled by the caller.
937 * Return the number of entries transferred.
939 static int transfer_objects(struct array_cache *to,
940 struct array_cache *from, unsigned int max)
942 /* Figure out how many entries to transfer */
943 int nr = min(min(from->avail, max), to->limit - to->avail);
948 memcpy(to->entry + to->avail, from->entry + from->avail -nr,
958 static void *__cache_alloc_node(struct kmem_cache *, gfp_t, int);
959 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
961 static struct array_cache **alloc_alien_cache(int node, int limit)
963 struct array_cache **ac_ptr;
964 int memsize = sizeof(void *) * MAX_NUMNODES;
969 ac_ptr = kmalloc_node(memsize, GFP_KERNEL, node);
972 if (i == node || !node_online(i)) {
976 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d);
978 for (i--; i <= 0; i--)
988 static void free_alien_cache(struct array_cache **ac_ptr)
999 static void __drain_alien_cache(struct kmem_cache *cachep,
1000 struct array_cache *ac, int node)
1002 struct kmem_list3 *rl3 = cachep->nodelists[node];
1005 spin_lock(&rl3->list_lock);
1007 * Stuff objects into the remote nodes shared array first.
1008 * That way we could avoid the overhead of putting the objects
1009 * into the free lists and getting them back later.
1012 transfer_objects(rl3->shared, ac, ac->limit);
1014 free_block(cachep, ac->entry, ac->avail, node);
1016 spin_unlock(&rl3->list_lock);
1021 * Called from cache_reap() to regularly drain alien caches round robin.
1023 static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
1025 int node = __get_cpu_var(reap_node);
1028 struct array_cache *ac = l3->alien[node];
1030 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1031 __drain_alien_cache(cachep, ac, node);
1032 spin_unlock_irq(&ac->lock);
1037 static void drain_alien_cache(struct kmem_cache *cachep,
1038 struct array_cache **alien)
1041 struct array_cache *ac;
1042 unsigned long flags;
1044 for_each_online_node(i) {
1047 spin_lock_irqsave(&ac->lock, flags);
1048 __drain_alien_cache(cachep, ac, i);
1049 spin_unlock_irqrestore(&ac->lock, flags);
1054 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1056 struct slab *slabp = virt_to_slab(objp);
1057 int nodeid = slabp->nodeid;
1058 struct kmem_list3 *l3;
1059 struct array_cache *alien = NULL;
1062 * Make sure we are not freeing a object from another node to the array
1063 * cache on this cpu.
1065 if (likely(slabp->nodeid == numa_node_id()))
1068 l3 = cachep->nodelists[numa_node_id()];
1069 STATS_INC_NODEFREES(cachep);
1070 if (l3->alien && l3->alien[nodeid]) {
1071 alien = l3->alien[nodeid];
1072 spin_lock(&alien->lock);
1073 if (unlikely(alien->avail == alien->limit)) {
1074 STATS_INC_ACOVERFLOW(cachep);
1075 __drain_alien_cache(cachep, alien, nodeid);
1077 alien->entry[alien->avail++] = objp;
1078 spin_unlock(&alien->lock);
1080 spin_lock(&(cachep->nodelists[nodeid])->list_lock);
1081 free_block(cachep, &objp, 1, nodeid);
1082 spin_unlock(&(cachep->nodelists[nodeid])->list_lock);
1089 #define drain_alien_cache(cachep, alien) do { } while (0)
1090 #define reap_alien(cachep, l3) do { } while (0)
1092 static inline struct array_cache **alloc_alien_cache(int node, int limit)
1094 return (struct array_cache **) 0x01020304ul;
1097 static inline void free_alien_cache(struct array_cache **ac_ptr)
1101 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1108 static int __cpuinit cpuup_callback(struct notifier_block *nfb,
1109 unsigned long action, void *hcpu)
1111 long cpu = (long)hcpu;
1112 struct kmem_cache *cachep;
1113 struct kmem_list3 *l3 = NULL;
1114 int node = cpu_to_node(cpu);
1115 int memsize = sizeof(struct kmem_list3);
1118 case CPU_UP_PREPARE:
1119 mutex_lock(&cache_chain_mutex);
1121 * We need to do this right in the beginning since
1122 * alloc_arraycache's are going to use this list.
1123 * kmalloc_node allows us to add the slab to the right
1124 * kmem_list3 and not this cpu's kmem_list3
1127 list_for_each_entry(cachep, &cache_chain, next) {
1129 * Set up the size64 kmemlist for cpu before we can
1130 * begin anything. Make sure some other cpu on this
1131 * node has not already allocated this
1133 if (!cachep->nodelists[node]) {
1134 l3 = kmalloc_node(memsize, GFP_KERNEL, node);
1137 kmem_list3_init(l3);
1138 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1139 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1142 * The l3s don't come and go as CPUs come and
1143 * go. cache_chain_mutex is sufficient
1146 cachep->nodelists[node] = l3;
1149 spin_lock_irq(&cachep->nodelists[node]->list_lock);
1150 cachep->nodelists[node]->free_limit =
1151 (1 + nr_cpus_node(node)) *
1152 cachep->batchcount + cachep->num;
1153 spin_unlock_irq(&cachep->nodelists[node]->list_lock);
1157 * Now we can go ahead with allocating the shared arrays and
1160 list_for_each_entry(cachep, &cache_chain, next) {
1161 struct array_cache *nc;
1162 struct array_cache *shared;
1163 struct array_cache **alien;
1165 nc = alloc_arraycache(node, cachep->limit,
1166 cachep->batchcount);
1169 shared = alloc_arraycache(node,
1170 cachep->shared * cachep->batchcount,
1175 alien = alloc_alien_cache(node, cachep->limit);
1178 cachep->array[cpu] = nc;
1179 l3 = cachep->nodelists[node];
1182 spin_lock_irq(&l3->list_lock);
1185 * We are serialised from CPU_DEAD or
1186 * CPU_UP_CANCELLED by the cpucontrol lock
1188 l3->shared = shared;
1197 spin_unlock_irq(&l3->list_lock);
1199 free_alien_cache(alien);
1201 mutex_unlock(&cache_chain_mutex);
1204 start_cpu_timer(cpu);
1206 #ifdef CONFIG_HOTPLUG_CPU
1209 * Even if all the cpus of a node are down, we don't free the
1210 * kmem_list3 of any cache. This to avoid a race between
1211 * cpu_down, and a kmalloc allocation from another cpu for
1212 * memory from the node of the cpu going down. The list3
1213 * structure is usually allocated from kmem_cache_create() and
1214 * gets destroyed at kmem_cache_destroy().
1217 case CPU_UP_CANCELED:
1218 mutex_lock(&cache_chain_mutex);
1219 list_for_each_entry(cachep, &cache_chain, next) {
1220 struct array_cache *nc;
1221 struct array_cache *shared;
1222 struct array_cache **alien;
1225 mask = node_to_cpumask(node);
1226 /* cpu is dead; no one can alloc from it. */
1227 nc = cachep->array[cpu];
1228 cachep->array[cpu] = NULL;
1229 l3 = cachep->nodelists[node];
1232 goto free_array_cache;
1234 spin_lock_irq(&l3->list_lock);
1236 /* Free limit for this kmem_list3 */
1237 l3->free_limit -= cachep->batchcount;
1239 free_block(cachep, nc->entry, nc->avail, node);
1241 if (!cpus_empty(mask)) {
1242 spin_unlock_irq(&l3->list_lock);
1243 goto free_array_cache;
1246 shared = l3->shared;
1248 free_block(cachep, l3->shared->entry,
1249 l3->shared->avail, node);
1256 spin_unlock_irq(&l3->list_lock);
1260 drain_alien_cache(cachep, alien);
1261 free_alien_cache(alien);
1267 * In the previous loop, all the objects were freed to
1268 * the respective cache's slabs, now we can go ahead and
1269 * shrink each nodelist to its limit.
1271 list_for_each_entry(cachep, &cache_chain, next) {
1272 l3 = cachep->nodelists[node];
1275 drain_freelist(cachep, l3, l3->free_objects);
1277 mutex_unlock(&cache_chain_mutex);
1283 mutex_unlock(&cache_chain_mutex);
1287 static struct notifier_block __cpuinitdata cpucache_notifier = {
1288 &cpuup_callback, NULL, 0
1292 * swap the static kmem_list3 with kmalloced memory
1294 static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
1297 struct kmem_list3 *ptr;
1299 BUG_ON(cachep->nodelists[nodeid] != list);
1300 ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, nodeid);
1303 local_irq_disable();
1304 memcpy(ptr, list, sizeof(struct kmem_list3));
1306 * Do not assume that spinlocks can be initialized via memcpy:
1308 spin_lock_init(&ptr->list_lock);
1310 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1311 cachep->nodelists[nodeid] = ptr;
1316 * Initialisation. Called after the page allocator have been initialised and
1317 * before smp_init().
1319 void __init kmem_cache_init(void)
1322 struct cache_sizes *sizes;
1323 struct cache_names *names;
1327 for (i = 0; i < NUM_INIT_LISTS; i++) {
1328 kmem_list3_init(&initkmem_list3[i]);
1329 if (i < MAX_NUMNODES)
1330 cache_cache.nodelists[i] = NULL;
1334 * Fragmentation resistance on low memory - only use bigger
1335 * page orders on machines with more than 32MB of memory.
1337 if (num_physpages > (32 << 20) >> PAGE_SHIFT)
1338 slab_break_gfp_order = BREAK_GFP_ORDER_HI;
1340 /* Bootstrap is tricky, because several objects are allocated
1341 * from caches that do not exist yet:
1342 * 1) initialize the cache_cache cache: it contains the struct
1343 * kmem_cache structures of all caches, except cache_cache itself:
1344 * cache_cache is statically allocated.
1345 * Initially an __init data area is used for the head array and the
1346 * kmem_list3 structures, it's replaced with a kmalloc allocated
1347 * array at the end of the bootstrap.
1348 * 2) Create the first kmalloc cache.
1349 * The struct kmem_cache for the new cache is allocated normally.
1350 * An __init data area is used for the head array.
1351 * 3) Create the remaining kmalloc caches, with minimally sized
1353 * 4) Replace the __init data head arrays for cache_cache and the first
1354 * kmalloc cache with kmalloc allocated arrays.
1355 * 5) Replace the __init data for kmem_list3 for cache_cache and
1356 * the other cache's with kmalloc allocated memory.
1357 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1360 /* 1) create the cache_cache */
1361 INIT_LIST_HEAD(&cache_chain);
1362 list_add(&cache_cache.next, &cache_chain);
1363 cache_cache.colour_off = cache_line_size();
1364 cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
1365 cache_cache.nodelists[numa_node_id()] = &initkmem_list3[CACHE_CACHE];
1367 cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
1370 for (order = 0; order < MAX_ORDER; order++) {
1371 cache_estimate(order, cache_cache.buffer_size,
1372 cache_line_size(), 0, &left_over, &cache_cache.num);
1373 if (cache_cache.num)
1376 BUG_ON(!cache_cache.num);
1377 cache_cache.gfporder = order;
1378 cache_cache.colour = left_over / cache_cache.colour_off;
1379 cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
1380 sizeof(struct slab), cache_line_size());
1382 /* 2+3) create the kmalloc caches */
1383 sizes = malloc_sizes;
1384 names = cache_names;
1387 * Initialize the caches that provide memory for the array cache and the
1388 * kmem_list3 structures first. Without this, further allocations will
1392 sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name,
1393 sizes[INDEX_AC].cs_size,
1394 ARCH_KMALLOC_MINALIGN,
1395 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1398 if (INDEX_AC != INDEX_L3) {
1399 sizes[INDEX_L3].cs_cachep =
1400 kmem_cache_create(names[INDEX_L3].name,
1401 sizes[INDEX_L3].cs_size,
1402 ARCH_KMALLOC_MINALIGN,
1403 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1407 slab_early_init = 0;
1409 while (sizes->cs_size != ULONG_MAX) {
1411 * For performance, all the general caches are L1 aligned.
1412 * This should be particularly beneficial on SMP boxes, as it
1413 * eliminates "false sharing".
1414 * Note for systems short on memory removing the alignment will
1415 * allow tighter packing of the smaller caches.
1417 if (!sizes->cs_cachep) {
1418 sizes->cs_cachep = kmem_cache_create(names->name,
1420 ARCH_KMALLOC_MINALIGN,
1421 ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1424 init_lock_keys(sizes);
1426 sizes->cs_dmacachep = kmem_cache_create(names->name_dma,
1428 ARCH_KMALLOC_MINALIGN,
1429 ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
1435 /* 4) Replace the bootstrap head arrays */
1437 struct array_cache *ptr;
1439 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1441 local_irq_disable();
1442 BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
1443 memcpy(ptr, cpu_cache_get(&cache_cache),
1444 sizeof(struct arraycache_init));
1446 * Do not assume that spinlocks can be initialized via memcpy:
1448 spin_lock_init(&ptr->lock);
1450 cache_cache.array[smp_processor_id()] = ptr;
1453 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1455 local_irq_disable();
1456 BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
1457 != &initarray_generic.cache);
1458 memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
1459 sizeof(struct arraycache_init));
1461 * Do not assume that spinlocks can be initialized via memcpy:
1463 spin_lock_init(&ptr->lock);
1465 malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
1469 /* 5) Replace the bootstrap kmem_list3's */
1472 /* Replace the static kmem_list3 structures for the boot cpu */
1473 init_list(&cache_cache, &initkmem_list3[CACHE_CACHE],
1476 for_each_online_node(node) {
1477 init_list(malloc_sizes[INDEX_AC].cs_cachep,
1478 &initkmem_list3[SIZE_AC + node], node);
1480 if (INDEX_AC != INDEX_L3) {
1481 init_list(malloc_sizes[INDEX_L3].cs_cachep,
1482 &initkmem_list3[SIZE_L3 + node],
1488 /* 6) resize the head arrays to their final sizes */
1490 struct kmem_cache *cachep;
1491 mutex_lock(&cache_chain_mutex);
1492 list_for_each_entry(cachep, &cache_chain, next)
1493 enable_cpucache(cachep);
1494 mutex_unlock(&cache_chain_mutex);
1498 g_cpucache_up = FULL;
1501 * Register a cpu startup notifier callback that initializes
1502 * cpu_cache_get for all new cpus
1504 register_cpu_notifier(&cpucache_notifier);
1507 * The reap timers are started later, with a module init call: That part
1508 * of the kernel is not yet operational.
1512 static int __init cpucache_init(void)
1517 * Register the timers that return unneeded pages to the page allocator
1519 for_each_online_cpu(cpu)
1520 start_cpu_timer(cpu);
1523 __initcall(cpucache_init);
1526 * Interface to system's page allocator. No need to hold the cache-lock.
1528 * If we requested dmaable memory, we will get it. Even if we
1529 * did not request dmaable memory, we might get it, but that
1530 * would be relatively rare and ignorable.
1532 static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
1540 * Nommu uses slab's for process anonymous memory allocations, and thus
1541 * requires __GFP_COMP to properly refcount higher order allocations
1543 flags |= __GFP_COMP;
1545 flags |= cachep->gfpflags;
1547 page = alloc_pages_node(nodeid, flags, cachep->gfporder);
1551 nr_pages = (1 << cachep->gfporder);
1552 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1553 atomic_add(nr_pages, &slab_reclaim_pages);
1554 add_zone_page_state(page_zone(page), NR_SLAB, nr_pages);
1555 for (i = 0; i < nr_pages; i++)
1556 __SetPageSlab(page + i);
1557 return page_address(page);
1561 * Interface to system's page release.
1563 static void kmem_freepages(struct kmem_cache *cachep, void *addr)
1565 unsigned long i = (1 << cachep->gfporder);
1566 struct page *page = virt_to_page(addr);
1567 const unsigned long nr_freed = i;
1569 sub_zone_page_state(page_zone(page), NR_SLAB, nr_freed);
1571 BUG_ON(!PageSlab(page));
1572 __ClearPageSlab(page);
1575 if (current->reclaim_state)
1576 current->reclaim_state->reclaimed_slab += nr_freed;
1577 free_pages((unsigned long)addr, cachep->gfporder);
1578 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1579 atomic_sub(1 << cachep->gfporder, &slab_reclaim_pages);
1582 static void kmem_rcu_free(struct rcu_head *head)
1584 struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
1585 struct kmem_cache *cachep = slab_rcu->cachep;
1587 kmem_freepages(cachep, slab_rcu->addr);
1588 if (OFF_SLAB(cachep))
1589 kmem_cache_free(cachep->slabp_cache, slab_rcu);
1594 #ifdef CONFIG_DEBUG_PAGEALLOC
1595 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1596 unsigned long caller)
1598 int size = obj_size(cachep);
1600 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1602 if (size < 5 * sizeof(unsigned long))
1605 *addr++ = 0x12345678;
1607 *addr++ = smp_processor_id();
1608 size -= 3 * sizeof(unsigned long);
1610 unsigned long *sptr = &caller;
1611 unsigned long svalue;
1613 while (!kstack_end(sptr)) {
1615 if (kernel_text_address(svalue)) {
1617 size -= sizeof(unsigned long);
1618 if (size <= sizeof(unsigned long))
1624 *addr++ = 0x87654321;
1628 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1630 int size = obj_size(cachep);
1631 addr = &((char *)addr)[obj_offset(cachep)];
1633 memset(addr, val, size);
1634 *(unsigned char *)(addr + size - 1) = POISON_END;
1637 static void dump_line(char *data, int offset, int limit)
1640 printk(KERN_ERR "%03x:", offset);
1641 for (i = 0; i < limit; i++)
1642 printk(" %02x", (unsigned char)data[offset + i]);
1649 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1654 if (cachep->flags & SLAB_RED_ZONE) {
1655 printk(KERN_ERR "Redzone: 0x%lx/0x%lx.\n",
1656 *dbg_redzone1(cachep, objp),
1657 *dbg_redzone2(cachep, objp));
1660 if (cachep->flags & SLAB_STORE_USER) {
1661 printk(KERN_ERR "Last user: [<%p>]",
1662 *dbg_userword(cachep, objp));
1663 print_symbol("(%s)",
1664 (unsigned long)*dbg_userword(cachep, objp));
1667 realobj = (char *)objp + obj_offset(cachep);
1668 size = obj_size(cachep);
1669 for (i = 0; i < size && lines; i += 16, lines--) {
1672 if (i + limit > size)
1674 dump_line(realobj, i, limit);
1678 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1684 realobj = (char *)objp + obj_offset(cachep);
1685 size = obj_size(cachep);
1687 for (i = 0; i < size; i++) {
1688 char exp = POISON_FREE;
1691 if (realobj[i] != exp) {
1697 "Slab corruption: start=%p, len=%d\n",
1699 print_objinfo(cachep, objp, 0);
1701 /* Hexdump the affected line */
1704 if (i + limit > size)
1706 dump_line(realobj, i, limit);
1709 /* Limit to 5 lines */
1715 /* Print some data about the neighboring objects, if they
1718 struct slab *slabp = virt_to_slab(objp);
1721 objnr = obj_to_index(cachep, slabp, objp);
1723 objp = index_to_obj(cachep, slabp, objnr - 1);
1724 realobj = (char *)objp + obj_offset(cachep);
1725 printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1727 print_objinfo(cachep, objp, 2);
1729 if (objnr + 1 < cachep->num) {
1730 objp = index_to_obj(cachep, slabp, objnr + 1);
1731 realobj = (char *)objp + obj_offset(cachep);
1732 printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1734 print_objinfo(cachep, objp, 2);
1742 * slab_destroy_objs - destroy a slab and its objects
1743 * @cachep: cache pointer being destroyed
1744 * @slabp: slab pointer being destroyed
1746 * Call the registered destructor for each object in a slab that is being
1749 static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
1752 for (i = 0; i < cachep->num; i++) {
1753 void *objp = index_to_obj(cachep, slabp, i);
1755 if (cachep->flags & SLAB_POISON) {
1756 #ifdef CONFIG_DEBUG_PAGEALLOC
1757 if (cachep->buffer_size % PAGE_SIZE == 0 &&
1759 kernel_map_pages(virt_to_page(objp),
1760 cachep->buffer_size / PAGE_SIZE, 1);
1762 check_poison_obj(cachep, objp);
1764 check_poison_obj(cachep, objp);
1767 if (cachep->flags & SLAB_RED_ZONE) {
1768 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1769 slab_error(cachep, "start of a freed object "
1771 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1772 slab_error(cachep, "end of a freed object "
1775 if (cachep->dtor && !(cachep->flags & SLAB_POISON))
1776 (cachep->dtor) (objp + obj_offset(cachep), cachep, 0);
1780 static void slab_destroy_objs(struct kmem_cache *cachep, struct slab *slabp)
1784 for (i = 0; i < cachep->num; i++) {
1785 void *objp = index_to_obj(cachep, slabp, i);
1786 (cachep->dtor) (objp, cachep, 0);
1793 * slab_destroy - destroy and release all objects in a slab
1794 * @cachep: cache pointer being destroyed
1795 * @slabp: slab pointer being destroyed
1797 * Destroy all the objs in a slab, and release the mem back to the system.
1798 * Before calling the slab must have been unlinked from the cache. The
1799 * cache-lock is not held/needed.
1801 static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
1803 void *addr = slabp->s_mem - slabp->colouroff;
1805 slab_destroy_objs(cachep, slabp);
1806 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
1807 struct slab_rcu *slab_rcu;
1809 slab_rcu = (struct slab_rcu *)slabp;
1810 slab_rcu->cachep = cachep;
1811 slab_rcu->addr = addr;
1812 call_rcu(&slab_rcu->head, kmem_rcu_free);
1814 kmem_freepages(cachep, addr);
1815 if (OFF_SLAB(cachep))
1816 kmem_cache_free(cachep->slabp_cache, slabp);
1821 * For setting up all the kmem_list3s for cache whose buffer_size is same as
1822 * size of kmem_list3.
1824 static void set_up_list3s(struct kmem_cache *cachep, int index)
1828 for_each_online_node(node) {
1829 cachep->nodelists[node] = &initkmem_list3[index + node];
1830 cachep->nodelists[node]->next_reap = jiffies +
1832 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1836 static void __kmem_cache_destroy(struct kmem_cache *cachep)
1839 struct kmem_list3 *l3;
1841 for_each_online_cpu(i)
1842 kfree(cachep->array[i]);
1844 /* NUMA: free the list3 structures */
1845 for_each_online_node(i) {
1846 l3 = cachep->nodelists[i];
1849 free_alien_cache(l3->alien);
1853 kmem_cache_free(&cache_cache, cachep);
1858 * calculate_slab_order - calculate size (page order) of slabs
1859 * @cachep: pointer to the cache that is being created
1860 * @size: size of objects to be created in this cache.
1861 * @align: required alignment for the objects.
1862 * @flags: slab allocation flags
1864 * Also calculates the number of objects per slab.
1866 * This could be made much more intelligent. For now, try to avoid using
1867 * high order pages for slabs. When the gfp() functions are more friendly
1868 * towards high-order requests, this should be changed.
1870 static size_t calculate_slab_order(struct kmem_cache *cachep,
1871 size_t size, size_t align, unsigned long flags)
1873 unsigned long offslab_limit;
1874 size_t left_over = 0;
1877 for (gfporder = 0; gfporder <= MAX_GFP_ORDER; gfporder++) {
1881 cache_estimate(gfporder, size, align, flags, &remainder, &num);
1885 if (flags & CFLGS_OFF_SLAB) {
1887 * Max number of objs-per-slab for caches which
1888 * use off-slab slabs. Needed to avoid a possible
1889 * looping condition in cache_grow().
1891 offslab_limit = size - sizeof(struct slab);
1892 offslab_limit /= sizeof(kmem_bufctl_t);
1894 if (num > offslab_limit)
1898 /* Found something acceptable - save it away */
1900 cachep->gfporder = gfporder;
1901 left_over = remainder;
1904 * A VFS-reclaimable slab tends to have most allocations
1905 * as GFP_NOFS and we really don't want to have to be allocating
1906 * higher-order pages when we are unable to shrink dcache.
1908 if (flags & SLAB_RECLAIM_ACCOUNT)
1912 * Large number of objects is good, but very large slabs are
1913 * currently bad for the gfp()s.
1915 if (gfporder >= slab_break_gfp_order)
1919 * Acceptable internal fragmentation?
1921 if (left_over * 8 <= (PAGE_SIZE << gfporder))
1927 static void setup_cpu_cache(struct kmem_cache *cachep)
1929 if (g_cpucache_up == FULL) {
1930 enable_cpucache(cachep);
1933 if (g_cpucache_up == NONE) {
1935 * Note: the first kmem_cache_create must create the cache
1936 * that's used by kmalloc(24), otherwise the creation of
1937 * further caches will BUG().
1939 cachep->array[smp_processor_id()] = &initarray_generic.cache;
1942 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
1943 * the first cache, then we need to set up all its list3s,
1944 * otherwise the creation of further caches will BUG().
1946 set_up_list3s(cachep, SIZE_AC);
1947 if (INDEX_AC == INDEX_L3)
1948 g_cpucache_up = PARTIAL_L3;
1950 g_cpucache_up = PARTIAL_AC;
1952 cachep->array[smp_processor_id()] =
1953 kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1955 if (g_cpucache_up == PARTIAL_AC) {
1956 set_up_list3s(cachep, SIZE_L3);
1957 g_cpucache_up = PARTIAL_L3;
1960 for_each_online_node(node) {
1961 cachep->nodelists[node] =
1962 kmalloc_node(sizeof(struct kmem_list3),
1964 BUG_ON(!cachep->nodelists[node]);
1965 kmem_list3_init(cachep->nodelists[node]);
1969 cachep->nodelists[numa_node_id()]->next_reap =
1970 jiffies + REAPTIMEOUT_LIST3 +
1971 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1973 cpu_cache_get(cachep)->avail = 0;
1974 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
1975 cpu_cache_get(cachep)->batchcount = 1;
1976 cpu_cache_get(cachep)->touched = 0;
1977 cachep->batchcount = 1;
1978 cachep->limit = BOOT_CPUCACHE_ENTRIES;
1982 * kmem_cache_create - Create a cache.
1983 * @name: A string which is used in /proc/slabinfo to identify this cache.
1984 * @size: The size of objects to be created in this cache.
1985 * @align: The required alignment for the objects.
1986 * @flags: SLAB flags
1987 * @ctor: A constructor for the objects.
1988 * @dtor: A destructor for the objects.
1990 * Returns a ptr to the cache on success, NULL on failure.
1991 * Cannot be called within a int, but can be interrupted.
1992 * The @ctor is run when new pages are allocated by the cache
1993 * and the @dtor is run before the pages are handed back.
1995 * @name must be valid until the cache is destroyed. This implies that
1996 * the module calling this has to destroy the cache before getting unloaded.
2000 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2001 * to catch references to uninitialised memory.
2003 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2004 * for buffer overruns.
2006 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2007 * cacheline. This can be beneficial if you're counting cycles as closely
2011 kmem_cache_create (const char *name, size_t size, size_t align,
2012 unsigned long flags,
2013 void (*ctor)(void*, struct kmem_cache *, unsigned long),
2014 void (*dtor)(void*, struct kmem_cache *, unsigned long))
2016 size_t left_over, slab_size, ralign;
2017 struct kmem_cache *cachep = NULL, *pc;
2020 * Sanity checks... these are all serious usage bugs.
2022 if (!name || in_interrupt() || (size < BYTES_PER_WORD) ||
2023 (size > (1 << MAX_OBJ_ORDER) * PAGE_SIZE) || (dtor && !ctor)) {
2024 printk(KERN_ERR "%s: Early error in slab %s\n", __FUNCTION__,
2030 * Prevent CPUs from coming and going.
2031 * lock_cpu_hotplug() nests outside cache_chain_mutex
2035 mutex_lock(&cache_chain_mutex);
2037 list_for_each_entry(pc, &cache_chain, next) {
2038 mm_segment_t old_fs = get_fs();
2043 * This happens when the module gets unloaded and doesn't
2044 * destroy its slab cache and no-one else reuses the vmalloc
2045 * area of the module. Print a warning.
2048 res = __get_user(tmp, pc->name);
2051 printk("SLAB: cache with size %d has lost its name\n",
2056 if (!strcmp(pc->name, name)) {
2057 printk("kmem_cache_create: duplicate cache %s\n", name);
2064 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
2065 if ((flags & SLAB_DEBUG_INITIAL) && !ctor) {
2066 /* No constructor, but inital state check requested */
2067 printk(KERN_ERR "%s: No con, but init state check "
2068 "requested - %s\n", __FUNCTION__, name);
2069 flags &= ~SLAB_DEBUG_INITIAL;
2073 * Enable redzoning and last user accounting, except for caches with
2074 * large objects, if the increased size would increase the object size
2075 * above the next power of two: caches with object sizes just above a
2076 * power of two have a significant amount of internal fragmentation.
2078 if (size < 4096 || fls(size - 1) == fls(size-1 + 3 * BYTES_PER_WORD))
2079 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2080 if (!(flags & SLAB_DESTROY_BY_RCU))
2081 flags |= SLAB_POISON;
2083 if (flags & SLAB_DESTROY_BY_RCU)
2084 BUG_ON(flags & SLAB_POISON);
2086 if (flags & SLAB_DESTROY_BY_RCU)
2090 * Always checks flags, a caller might be expecting debug support which
2093 BUG_ON(flags & ~CREATE_MASK);
2096 * Check that size is in terms of words. This is needed to avoid
2097 * unaligned accesses for some archs when redzoning is used, and makes
2098 * sure any on-slab bufctl's are also correctly aligned.
2100 if (size & (BYTES_PER_WORD - 1)) {
2101 size += (BYTES_PER_WORD - 1);
2102 size &= ~(BYTES_PER_WORD - 1);
2105 /* calculate the final buffer alignment: */
2107 /* 1) arch recommendation: can be overridden for debug */
2108 if (flags & SLAB_HWCACHE_ALIGN) {
2110 * Default alignment: as specified by the arch code. Except if
2111 * an object is really small, then squeeze multiple objects into
2114 ralign = cache_line_size();
2115 while (size <= ralign / 2)
2118 ralign = BYTES_PER_WORD;
2122 * Redzoning and user store require word alignment. Note this will be
2123 * overridden by architecture or caller mandated alignment if either
2124 * is greater than BYTES_PER_WORD.
2126 if (flags & SLAB_RED_ZONE || flags & SLAB_STORE_USER)
2127 ralign = BYTES_PER_WORD;
2129 /* 2) arch mandated alignment: disables debug if necessary */
2130 if (ralign < ARCH_SLAB_MINALIGN) {
2131 ralign = ARCH_SLAB_MINALIGN;
2132 if (ralign > BYTES_PER_WORD)
2133 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2135 /* 3) caller mandated alignment: disables debug if necessary */
2136 if (ralign < align) {
2138 if (ralign > BYTES_PER_WORD)
2139 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2146 /* Get cache's description obj. */
2147 cachep = kmem_cache_zalloc(&cache_cache, SLAB_KERNEL);
2152 cachep->obj_size = size;
2155 * Both debugging options require word-alignment which is calculated
2158 if (flags & SLAB_RED_ZONE) {
2159 /* add space for red zone words */
2160 cachep->obj_offset += BYTES_PER_WORD;
2161 size += 2 * BYTES_PER_WORD;
2163 if (flags & SLAB_STORE_USER) {
2164 /* user store requires one word storage behind the end of
2167 size += BYTES_PER_WORD;
2169 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2170 if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
2171 && cachep->obj_size > cache_line_size() && size < PAGE_SIZE) {
2172 cachep->obj_offset += PAGE_SIZE - size;
2179 * Determine if the slab management is 'on' or 'off' slab.
2180 * (bootstrapping cannot cope with offslab caches so don't do
2183 if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init)
2185 * Size is large, assume best to place the slab management obj
2186 * off-slab (should allow better packing of objs).
2188 flags |= CFLGS_OFF_SLAB;
2190 size = ALIGN(size, align);
2192 left_over = calculate_slab_order(cachep, size, align, flags);
2195 printk("kmem_cache_create: couldn't create cache %s.\n", name);
2196 kmem_cache_free(&cache_cache, cachep);
2200 slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
2201 + sizeof(struct slab), align);
2204 * If the slab has been placed off-slab, and we have enough space then
2205 * move it on-slab. This is at the expense of any extra colouring.
2207 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
2208 flags &= ~CFLGS_OFF_SLAB;
2209 left_over -= slab_size;
2212 if (flags & CFLGS_OFF_SLAB) {
2213 /* really off slab. No need for manual alignment */
2215 cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
2218 cachep->colour_off = cache_line_size();
2219 /* Offset must be a multiple of the alignment. */
2220 if (cachep->colour_off < align)
2221 cachep->colour_off = align;
2222 cachep->colour = left_over / cachep->colour_off;
2223 cachep->slab_size = slab_size;
2224 cachep->flags = flags;
2225 cachep->gfpflags = 0;
2226 if (flags & SLAB_CACHE_DMA)
2227 cachep->gfpflags |= GFP_DMA;
2228 cachep->buffer_size = size;
2230 if (flags & CFLGS_OFF_SLAB) {
2231 cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
2233 * This is a possibility for one of the malloc_sizes caches.
2234 * But since we go off slab only for object size greater than
2235 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2236 * this should not happen at all.
2237 * But leave a BUG_ON for some lucky dude.
2239 BUG_ON(!cachep->slabp_cache);
2241 cachep->ctor = ctor;
2242 cachep->dtor = dtor;
2243 cachep->name = name;
2246 setup_cpu_cache(cachep);
2248 /* cache setup completed, link it into the list */
2249 list_add(&cachep->next, &cache_chain);
2251 if (!cachep && (flags & SLAB_PANIC))
2252 panic("kmem_cache_create(): failed to create slab `%s'\n",
2254 mutex_unlock(&cache_chain_mutex);
2255 unlock_cpu_hotplug();
2258 EXPORT_SYMBOL(kmem_cache_create);
2261 static void check_irq_off(void)
2263 BUG_ON(!irqs_disabled());
2266 static void check_irq_on(void)
2268 BUG_ON(irqs_disabled());
2271 static void check_spinlock_acquired(struct kmem_cache *cachep)
2275 assert_spin_locked(&cachep->nodelists[numa_node_id()]->list_lock);
2279 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2283 assert_spin_locked(&cachep->nodelists[node]->list_lock);
2288 #define check_irq_off() do { } while(0)
2289 #define check_irq_on() do { } while(0)
2290 #define check_spinlock_acquired(x) do { } while(0)
2291 #define check_spinlock_acquired_node(x, y) do { } while(0)
2294 static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
2295 struct array_cache *ac,
2296 int force, int node);
2298 static void do_drain(void *arg)
2300 struct kmem_cache *cachep = arg;
2301 struct array_cache *ac;
2302 int node = numa_node_id();
2305 ac = cpu_cache_get(cachep);
2306 spin_lock(&cachep->nodelists[node]->list_lock);
2307 free_block(cachep, ac->entry, ac->avail, node);
2308 spin_unlock(&cachep->nodelists[node]->list_lock);
2312 static void drain_cpu_caches(struct kmem_cache *cachep)
2314 struct kmem_list3 *l3;
2317 on_each_cpu(do_drain, cachep, 1, 1);
2319 for_each_online_node(node) {
2320 l3 = cachep->nodelists[node];
2321 if (l3 && l3->alien)
2322 drain_alien_cache(cachep, l3->alien);
2325 for_each_online_node(node) {
2326 l3 = cachep->nodelists[node];
2328 drain_array(cachep, l3, l3->shared, 1, node);
2333 * Remove slabs from the list of free slabs.
2334 * Specify the number of slabs to drain in tofree.
2336 * Returns the actual number of slabs released.
2338 static int drain_freelist(struct kmem_cache *cache,
2339 struct kmem_list3 *l3, int tofree)
2341 struct list_head *p;
2346 while (nr_freed < tofree && !list_empty(&l3->slabs_free)) {
2348 spin_lock_irq(&l3->list_lock);
2349 p = l3->slabs_free.prev;
2350 if (p == &l3->slabs_free) {
2351 spin_unlock_irq(&l3->list_lock);
2355 slabp = list_entry(p, struct slab, list);
2357 BUG_ON(slabp->inuse);
2359 list_del(&slabp->list);
2361 * Safe to drop the lock. The slab is no longer linked
2364 l3->free_objects -= cache->num;
2365 spin_unlock_irq(&l3->list_lock);
2366 slab_destroy(cache, slabp);
2373 static int __cache_shrink(struct kmem_cache *cachep)
2376 struct kmem_list3 *l3;
2378 drain_cpu_caches(cachep);
2381 for_each_online_node(i) {
2382 l3 = cachep->nodelists[i];
2386 drain_freelist(cachep, l3, l3->free_objects);
2388 ret += !list_empty(&l3->slabs_full) ||
2389 !list_empty(&l3->slabs_partial);
2391 return (ret ? 1 : 0);
2395 * kmem_cache_shrink - Shrink a cache.
2396 * @cachep: The cache to shrink.
2398 * Releases as many slabs as possible for a cache.
2399 * To help debugging, a zero exit status indicates all slabs were released.
2401 int kmem_cache_shrink(struct kmem_cache *cachep)
2403 BUG_ON(!cachep || in_interrupt());
2405 return __cache_shrink(cachep);
2407 EXPORT_SYMBOL(kmem_cache_shrink);
2410 * kmem_cache_destroy - delete a cache
2411 * @cachep: the cache to destroy
2413 * Remove a struct kmem_cache object from the slab cache.
2414 * Returns 0 on success.
2416 * It is expected this function will be called by a module when it is
2417 * unloaded. This will remove the cache completely, and avoid a duplicate
2418 * cache being allocated each time a module is loaded and unloaded, if the
2419 * module doesn't have persistent in-kernel storage across loads and unloads.
2421 * The cache must be empty before calling this function.
2423 * The caller must guarantee that noone will allocate memory from the cache
2424 * during the kmem_cache_destroy().
2426 int kmem_cache_destroy(struct kmem_cache *cachep)
2428 BUG_ON(!cachep || in_interrupt());
2430 /* Don't let CPUs to come and go */
2433 /* Find the cache in the chain of caches. */
2434 mutex_lock(&cache_chain_mutex);
2436 * the chain is never empty, cache_cache is never destroyed
2438 list_del(&cachep->next);
2439 mutex_unlock(&cache_chain_mutex);
2441 if (__cache_shrink(cachep)) {
2442 slab_error(cachep, "Can't free all objects");
2443 mutex_lock(&cache_chain_mutex);
2444 list_add(&cachep->next, &cache_chain);
2445 mutex_unlock(&cache_chain_mutex);
2446 unlock_cpu_hotplug();
2450 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
2453 __kmem_cache_destroy(cachep);
2454 unlock_cpu_hotplug();
2457 EXPORT_SYMBOL(kmem_cache_destroy);
2460 * Get the memory for a slab management obj.
2461 * For a slab cache when the slab descriptor is off-slab, slab descriptors
2462 * always come from malloc_sizes caches. The slab descriptor cannot
2463 * come from the same cache which is getting created because,
2464 * when we are searching for an appropriate cache for these
2465 * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2466 * If we are creating a malloc_sizes cache here it would not be visible to
2467 * kmem_find_general_cachep till the initialization is complete.
2468 * Hence we cannot have slabp_cache same as the original cache.
2470 static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,
2471 int colour_off, gfp_t local_flags,
2476 if (OFF_SLAB(cachep)) {
2477 /* Slab management obj is off-slab. */
2478 slabp = kmem_cache_alloc_node(cachep->slabp_cache,
2479 local_flags, nodeid);
2483 slabp = objp + colour_off;
2484 colour_off += cachep->slab_size;
2487 slabp->colouroff = colour_off;
2488 slabp->s_mem = objp + colour_off;
2489 slabp->nodeid = nodeid;
2493 static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
2495 return (kmem_bufctl_t *) (slabp + 1);
2498 static void cache_init_objs(struct kmem_cache *cachep,
2499 struct slab *slabp, unsigned long ctor_flags)
2503 for (i = 0; i < cachep->num; i++) {
2504 void *objp = index_to_obj(cachep, slabp, i);
2506 /* need to poison the objs? */
2507 if (cachep->flags & SLAB_POISON)
2508 poison_obj(cachep, objp, POISON_FREE);
2509 if (cachep->flags & SLAB_STORE_USER)
2510 *dbg_userword(cachep, objp) = NULL;
2512 if (cachep->flags & SLAB_RED_ZONE) {
2513 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2514 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2517 * Constructors are not allowed to allocate memory from the same
2518 * cache which they are a constructor for. Otherwise, deadlock.
2519 * They must also be threaded.
2521 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2522 cachep->ctor(objp + obj_offset(cachep), cachep,
2525 if (cachep->flags & SLAB_RED_ZONE) {
2526 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2527 slab_error(cachep, "constructor overwrote the"
2528 " end of an object");
2529 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2530 slab_error(cachep, "constructor overwrote the"
2531 " start of an object");
2533 if ((cachep->buffer_size % PAGE_SIZE) == 0 &&
2534 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2535 kernel_map_pages(virt_to_page(objp),
2536 cachep->buffer_size / PAGE_SIZE, 0);
2539 cachep->ctor(objp, cachep, ctor_flags);
2541 slab_bufctl(slabp)[i] = i + 1;
2543 slab_bufctl(slabp)[i - 1] = BUFCTL_END;
2547 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2549 if (flags & SLAB_DMA)
2550 BUG_ON(!(cachep->gfpflags & GFP_DMA));
2552 BUG_ON(cachep->gfpflags & GFP_DMA);
2555 static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
2558 void *objp = index_to_obj(cachep, slabp, slabp->free);
2562 next = slab_bufctl(slabp)[slabp->free];
2564 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2565 WARN_ON(slabp->nodeid != nodeid);
2572 static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
2573 void *objp, int nodeid)
2575 unsigned int objnr = obj_to_index(cachep, slabp, objp);
2578 /* Verify that the slab belongs to the intended node */
2579 WARN_ON(slabp->nodeid != nodeid);
2581 if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
2582 printk(KERN_ERR "slab: double free detected in cache "
2583 "'%s', objp %p\n", cachep->name, objp);
2587 slab_bufctl(slabp)[objnr] = slabp->free;
2588 slabp->free = objnr;
2593 * Map pages beginning at addr to the given cache and slab. This is required
2594 * for the slab allocator to be able to lookup the cache and slab of a
2595 * virtual address for kfree, ksize, kmem_ptr_validate, and slab debugging.
2597 static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
2603 page = virt_to_page(addr);
2606 if (likely(!PageCompound(page)))
2607 nr_pages <<= cache->gfporder;
2610 page_set_cache(page, cache);
2611 page_set_slab(page, slab);
2613 } while (--nr_pages);
2617 * Grow (by 1) the number of slabs within a cache. This is called by
2618 * kmem_cache_alloc() when there are no active objs left in a cache.
2620 static int cache_grow(struct kmem_cache *cachep, gfp_t flags, int nodeid)
2626 unsigned long ctor_flags;
2627 struct kmem_list3 *l3;
2630 * Be lazy and only check for valid flags here, keeping it out of the
2631 * critical path in kmem_cache_alloc().
2633 BUG_ON(flags & ~(SLAB_DMA | SLAB_LEVEL_MASK | SLAB_NO_GROW));
2634 if (flags & SLAB_NO_GROW)
2637 ctor_flags = SLAB_CTOR_CONSTRUCTOR;
2638 local_flags = (flags & SLAB_LEVEL_MASK);
2639 if (!(local_flags & __GFP_WAIT))
2641 * Not allowed to sleep. Need to tell a constructor about
2642 * this - it might need to know...
2644 ctor_flags |= SLAB_CTOR_ATOMIC;
2646 /* Take the l3 list lock to change the colour_next on this node */
2648 l3 = cachep->nodelists[nodeid];
2649 spin_lock(&l3->list_lock);
2651 /* Get colour for the slab, and cal the next value. */
2652 offset = l3->colour_next;
2654 if (l3->colour_next >= cachep->colour)
2655 l3->colour_next = 0;
2656 spin_unlock(&l3->list_lock);
2658 offset *= cachep->colour_off;
2660 if (local_flags & __GFP_WAIT)
2664 * The test for missing atomic flag is performed here, rather than
2665 * the more obvious place, simply to reduce the critical path length
2666 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2667 * will eventually be caught here (where it matters).
2669 kmem_flagcheck(cachep, flags);
2672 * Get mem for the objs. Attempt to allocate a physical page from
2675 objp = kmem_getpages(cachep, flags, nodeid);
2679 /* Get slab management. */
2680 slabp = alloc_slabmgmt(cachep, objp, offset, local_flags, nodeid);
2684 slabp->nodeid = nodeid;
2685 slab_map_pages(cachep, slabp, objp);
2687 cache_init_objs(cachep, slabp, ctor_flags);
2689 if (local_flags & __GFP_WAIT)
2690 local_irq_disable();
2692 spin_lock(&l3->list_lock);
2694 /* Make slab active. */
2695 list_add_tail(&slabp->list, &(l3->slabs_free));
2696 STATS_INC_GROWN(cachep);
2697 l3->free_objects += cachep->num;
2698 spin_unlock(&l3->list_lock);
2701 kmem_freepages(cachep, objp);
2703 if (local_flags & __GFP_WAIT)
2704 local_irq_disable();
2711 * Perform extra freeing checks:
2712 * - detect bad pointers.
2713 * - POISON/RED_ZONE checking
2714 * - destructor calls, for caches with POISON+dtor
2716 static void kfree_debugcheck(const void *objp)
2720 if (!virt_addr_valid(objp)) {
2721 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2722 (unsigned long)objp);
2725 page = virt_to_page(objp);
2726 if (!PageSlab(page)) {
2727 printk(KERN_ERR "kfree_debugcheck: bad ptr %lxh.\n",
2728 (unsigned long)objp);
2733 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2735 unsigned long redzone1, redzone2;
2737 redzone1 = *dbg_redzone1(cache, obj);
2738 redzone2 = *dbg_redzone2(cache, obj);
2743 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2746 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2747 slab_error(cache, "double free detected");
2749 slab_error(cache, "memory outside object was overwritten");
2751 printk(KERN_ERR "%p: redzone 1:0x%lx, redzone 2:0x%lx.\n",
2752 obj, redzone1, redzone2);
2755 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2762 objp -= obj_offset(cachep);
2763 kfree_debugcheck(objp);
2764 page = virt_to_page(objp);
2766 slabp = page_get_slab(page);
2768 if (cachep->flags & SLAB_RED_ZONE) {
2769 verify_redzone_free(cachep, objp);
2770 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2771 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2773 if (cachep->flags & SLAB_STORE_USER)
2774 *dbg_userword(cachep, objp) = caller;
2776 objnr = obj_to_index(cachep, slabp, objp);
2778 BUG_ON(objnr >= cachep->num);
2779 BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
2781 if (cachep->flags & SLAB_DEBUG_INITIAL) {
2783 * Need to call the slab's constructor so the caller can
2784 * perform a verify of its state (debugging). Called without
2785 * the cache-lock held.
2787 cachep->ctor(objp + obj_offset(cachep),
2788 cachep, SLAB_CTOR_CONSTRUCTOR | SLAB_CTOR_VERIFY);
2790 if (cachep->flags & SLAB_POISON && cachep->dtor) {
2791 /* we want to cache poison the object,
2792 * call the destruction callback
2794 cachep->dtor(objp + obj_offset(cachep), cachep, 0);
2796 #ifdef CONFIG_DEBUG_SLAB_LEAK
2797 slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
2799 if (cachep->flags & SLAB_POISON) {
2800 #ifdef CONFIG_DEBUG_PAGEALLOC
2801 if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2802 store_stackinfo(cachep, objp, (unsigned long)caller);
2803 kernel_map_pages(virt_to_page(objp),
2804 cachep->buffer_size / PAGE_SIZE, 0);
2806 poison_obj(cachep, objp, POISON_FREE);
2809 poison_obj(cachep, objp, POISON_FREE);
2815 static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
2820 /* Check slab's freelist to see if this obj is there. */
2821 for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
2823 if (entries > cachep->num || i >= cachep->num)
2826 if (entries != cachep->num - slabp->inuse) {
2828 printk(KERN_ERR "slab: Internal list corruption detected in "
2829 "cache '%s'(%d), slabp %p(%d). Hexdump:\n",
2830 cachep->name, cachep->num, slabp, slabp->inuse);
2832 i < sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t);
2835 printk("\n%03x:", i);
2836 printk(" %02x", ((unsigned char *)slabp)[i]);
2843 #define kfree_debugcheck(x) do { } while(0)
2844 #define cache_free_debugcheck(x,objp,z) (objp)
2845 #define check_slabp(x,y) do { } while(0)
2848 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
2851 struct kmem_list3 *l3;
2852 struct array_cache *ac;
2855 ac = cpu_cache_get(cachep);
2857 batchcount = ac->batchcount;
2858 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2860 * If there was little recent activity on this cache, then
2861 * perform only a partial refill. Otherwise we could generate
2864 batchcount = BATCHREFILL_LIMIT;
2866 l3 = cachep->nodelists[numa_node_id()];
2868 BUG_ON(ac->avail > 0 || !l3);
2869 spin_lock(&l3->list_lock);
2871 /* See if we can refill from the shared array */
2872 if (l3->shared && transfer_objects(ac, l3->shared, batchcount))
2875 while (batchcount > 0) {
2876 struct list_head *entry;
2878 /* Get slab alloc is to come from. */
2879 entry = l3->slabs_partial.next;
2880 if (entry == &l3->slabs_partial) {
2881 l3->free_touched = 1;
2882 entry = l3->slabs_free.next;
2883 if (entry == &l3->slabs_free)
2887 slabp = list_entry(entry, struct slab, list);
2888 check_slabp(cachep, slabp);
2889 check_spinlock_acquired(cachep);
2890 while (slabp->inuse < cachep->num && batchcount--) {
2891 STATS_INC_ALLOCED(cachep);
2892 STATS_INC_ACTIVE(cachep);
2893 STATS_SET_HIGH(cachep);
2895 ac->entry[ac->avail++] = slab_get_obj(cachep, slabp,
2898 check_slabp(cachep, slabp);
2900 /* move slabp to correct slabp list: */
2901 list_del(&slabp->list);
2902 if (slabp->free == BUFCTL_END)
2903 list_add(&slabp->list, &l3->slabs_full);
2905 list_add(&slabp->list, &l3->slabs_partial);
2909 l3->free_objects -= ac->avail;
2911 spin_unlock(&l3->list_lock);
2913 if (unlikely(!ac->avail)) {
2915 x = cache_grow(cachep, flags, numa_node_id());
2917 /* cache_grow can reenable interrupts, then ac could change. */
2918 ac = cpu_cache_get(cachep);
2919 if (!x && ac->avail == 0) /* no objects in sight? abort */
2922 if (!ac->avail) /* objects refilled by interrupt? */
2926 return ac->entry[--ac->avail];
2929 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
2932 might_sleep_if(flags & __GFP_WAIT);
2934 kmem_flagcheck(cachep, flags);
2939 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
2940 gfp_t flags, void *objp, void *caller)
2944 if (cachep->flags & SLAB_POISON) {
2945 #ifdef CONFIG_DEBUG_PAGEALLOC
2946 if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
2947 kernel_map_pages(virt_to_page(objp),
2948 cachep->buffer_size / PAGE_SIZE, 1);
2950 check_poison_obj(cachep, objp);
2952 check_poison_obj(cachep, objp);
2954 poison_obj(cachep, objp, POISON_INUSE);
2956 if (cachep->flags & SLAB_STORE_USER)
2957 *dbg_userword(cachep, objp) = caller;
2959 if (cachep->flags & SLAB_RED_ZONE) {
2960 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
2961 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
2962 slab_error(cachep, "double free, or memory outside"
2963 " object was overwritten");
2965 "%p: redzone 1:0x%lx, redzone 2:0x%lx\n",
2966 objp, *dbg_redzone1(cachep, objp),
2967 *dbg_redzone2(cachep, objp));
2969 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
2970 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
2972 #ifdef CONFIG_DEBUG_SLAB_LEAK
2977 slabp = page_get_slab(virt_to_page(objp));
2978 objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;
2979 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
2982 objp += obj_offset(cachep);
2983 if (cachep->ctor && cachep->flags & SLAB_POISON) {
2984 unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR;
2986 if (!(flags & __GFP_WAIT))
2987 ctor_flags |= SLAB_CTOR_ATOMIC;
2989 cachep->ctor(objp, cachep, ctor_flags);
2994 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
2997 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3000 struct array_cache *ac;
3003 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
3004 objp = alternate_node_alloc(cachep, flags);
3011 ac = cpu_cache_get(cachep);
3012 if (likely(ac->avail)) {
3013 STATS_INC_ALLOCHIT(cachep);
3015 objp = ac->entry[--ac->avail];
3017 STATS_INC_ALLOCMISS(cachep);
3018 objp = cache_alloc_refill(cachep, flags);
3023 static __always_inline void *__cache_alloc(struct kmem_cache *cachep,
3024 gfp_t flags, void *caller)
3026 unsigned long save_flags;
3029 cache_alloc_debugcheck_before(cachep, flags);
3031 local_irq_save(save_flags);
3032 objp = ____cache_alloc(cachep, flags);
3033 local_irq_restore(save_flags);
3034 objp = cache_alloc_debugcheck_after(cachep, flags, objp,
3042 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3044 * If we are in_interrupt, then process context, including cpusets and
3045 * mempolicy, may not apply and should not be used for allocation policy.
3047 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3049 int nid_alloc, nid_here;
3053 nid_alloc = nid_here = numa_node_id();
3054 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3055 nid_alloc = cpuset_mem_spread_node();
3056 else if (current->mempolicy)
3057 nid_alloc = slab_node(current->mempolicy);
3058 if (nid_alloc != nid_here)
3059 return __cache_alloc_node(cachep, flags, nid_alloc);
3064 * A interface to enable slab creation on nodeid
3066 static void *__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3069 struct list_head *entry;
3071 struct kmem_list3 *l3;
3075 l3 = cachep->nodelists[nodeid];
3080 spin_lock(&l3->list_lock);
3081 entry = l3->slabs_partial.next;
3082 if (entry == &l3->slabs_partial) {
3083 l3->free_touched = 1;
3084 entry = l3->slabs_free.next;
3085 if (entry == &l3->slabs_free)
3089 slabp = list_entry(entry, struct slab, list);
3090 check_spinlock_acquired_node(cachep, nodeid);
3091 check_slabp(cachep, slabp);
3093 STATS_INC_NODEALLOCS(cachep);
3094 STATS_INC_ACTIVE(cachep);
3095 STATS_SET_HIGH(cachep);
3097 BUG_ON(slabp->inuse == cachep->num);
3099 obj = slab_get_obj(cachep, slabp, nodeid);
3100 check_slabp(cachep, slabp);
3102 /* move slabp to correct slabp list: */
3103 list_del(&slabp->list);
3105 if (slabp->free == BUFCTL_END)
3106 list_add(&slabp->list, &l3->slabs_full);
3108 list_add(&slabp->list, &l3->slabs_partial);
3110 spin_unlock(&l3->list_lock);
3114 spin_unlock(&l3->list_lock);
3115 x = cache_grow(cachep, flags, nodeid);
3127 * Caller needs to acquire correct kmem_list's list_lock
3129 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
3133 struct kmem_list3 *l3;
3135 for (i = 0; i < nr_objects; i++) {
3136 void *objp = objpp[i];
3139 slabp = virt_to_slab(objp);
3140 l3 = cachep->nodelists[node];
3141 list_del(&slabp->list);
3142 check_spinlock_acquired_node(cachep, node);
3143 check_slabp(cachep, slabp);
3144 slab_put_obj(cachep, slabp, objp, node);
3145 STATS_DEC_ACTIVE(cachep);
3147 check_slabp(cachep, slabp);
3149 /* fixup slab chains */
3150 if (slabp->inuse == 0) {
3151 if (l3->free_objects > l3->free_limit) {
3152 l3->free_objects -= cachep->num;
3153 /* No need to drop any previously held
3154 * lock here, even if we have a off-slab slab
3155 * descriptor it is guaranteed to come from
3156 * a different cache, refer to comments before
3159 slab_destroy(cachep, slabp);
3161 list_add(&slabp->list, &l3->slabs_free);
3164 /* Unconditionally move a slab to the end of the
3165 * partial list on free - maximum time for the
3166 * other objects to be freed, too.
3168 list_add_tail(&slabp->list, &l3->slabs_partial);
3173 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3176 struct kmem_list3 *l3;
3177 int node = numa_node_id();
3179 batchcount = ac->batchcount;
3181 BUG_ON(!batchcount || batchcount > ac->avail);
3184 l3 = cachep->nodelists[node];
3185 spin_lock(&l3->list_lock);
3187 struct array_cache *shared_array = l3->shared;
3188 int max = shared_array->limit - shared_array->avail;
3190 if (batchcount > max)
3192 memcpy(&(shared_array->entry[shared_array->avail]),
3193 ac->entry, sizeof(void *) * batchcount);
3194 shared_array->avail += batchcount;
3199 free_block(cachep, ac->entry, batchcount, node);
3204 struct list_head *p;
3206 p = l3->slabs_free.next;
3207 while (p != &(l3->slabs_free)) {
3210 slabp = list_entry(p, struct slab, list);
3211 BUG_ON(slabp->inuse);
3216 STATS_SET_FREEABLE(cachep, i);
3219 spin_unlock(&l3->list_lock);
3220 ac->avail -= batchcount;
3221 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3225 * Release an obj back to its cache. If the obj has a constructed state, it must
3226 * be in this state _before_ it is released. Called with disabled ints.
3228 static inline void __cache_free(struct kmem_cache *cachep, void *objp)
3230 struct array_cache *ac = cpu_cache_get(cachep);
3233 objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
3235 if (cache_free_alien(cachep, objp))
3238 if (likely(ac->avail < ac->limit)) {
3239 STATS_INC_FREEHIT(cachep);
3240 ac->entry[ac->avail++] = objp;
3243 STATS_INC_FREEMISS(cachep);
3244 cache_flusharray(cachep, ac);
3245 ac->entry[ac->avail++] = objp;
3250 * kmem_cache_alloc - Allocate an object
3251 * @cachep: The cache to allocate from.
3252 * @flags: See kmalloc().
3254 * Allocate an object from this cache. The flags are only relevant
3255 * if the cache has no available objects.
3257 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3259 return __cache_alloc(cachep, flags, __builtin_return_address(0));
3261 EXPORT_SYMBOL(kmem_cache_alloc);
3264 * kmem_cache_zalloc - Allocate an object. The memory is set to zero.
3265 * @cache: The cache to allocate from.
3266 * @flags: See kmalloc().
3268 * Allocate an object from this cache and set the allocated memory to zero.
3269 * The flags are only relevant if the cache has no available objects.
3271 void *kmem_cache_zalloc(struct kmem_cache *cache, gfp_t flags)
3273 void *ret = __cache_alloc(cache, flags, __builtin_return_address(0));
3275 memset(ret, 0, obj_size(cache));
3278 EXPORT_SYMBOL(kmem_cache_zalloc);
3281 * kmem_ptr_validate - check if an untrusted pointer might
3283 * @cachep: the cache we're checking against
3284 * @ptr: pointer to validate
3286 * This verifies that the untrusted pointer looks sane:
3287 * it is _not_ a guarantee that the pointer is actually
3288 * part of the slab cache in question, but it at least
3289 * validates that the pointer can be dereferenced and
3290 * looks half-way sane.
3292 * Currently only used for dentry validation.
3294 int fastcall kmem_ptr_validate(struct kmem_cache *cachep, void *ptr)
3296 unsigned long addr = (unsigned long)ptr;
3297 unsigned long min_addr = PAGE_OFFSET;
3298 unsigned long align_mask = BYTES_PER_WORD - 1;
3299 unsigned long size = cachep->buffer_size;
3302 if (unlikely(addr < min_addr))
3304 if (unlikely(addr > (unsigned long)high_memory - size))
3306 if (unlikely(addr & align_mask))
3308 if (unlikely(!kern_addr_valid(addr)))
3310 if (unlikely(!kern_addr_valid(addr + size - 1)))
3312 page = virt_to_page(ptr);
3313 if (unlikely(!PageSlab(page)))
3315 if (unlikely(page_get_cache(page) != cachep))
3324 * kmem_cache_alloc_node - Allocate an object on the specified node
3325 * @cachep: The cache to allocate from.
3326 * @flags: See kmalloc().
3327 * @nodeid: node number of the target node.
3329 * Identical to kmem_cache_alloc, except that this function is slow
3330 * and can sleep. And it will allocate memory on the given node, which
3331 * can improve the performance for cpu bound structures.
3332 * New and improved: it will now make sure that the object gets
3333 * put on the correct node list so that there is no false sharing.
3335 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3337 unsigned long save_flags;
3340 cache_alloc_debugcheck_before(cachep, flags);
3341 local_irq_save(save_flags);
3343 if (nodeid == -1 || nodeid == numa_node_id() ||
3344 !cachep->nodelists[nodeid])
3345 ptr = ____cache_alloc(cachep, flags);
3347 ptr = __cache_alloc_node(cachep, flags, nodeid);
3348 local_irq_restore(save_flags);
3350 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr,
3351 __builtin_return_address(0));
3355 EXPORT_SYMBOL(kmem_cache_alloc_node);
3357 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3359 struct kmem_cache *cachep;
3361 cachep = kmem_find_general_cachep(size, flags);
3362 if (unlikely(cachep == NULL))
3364 return kmem_cache_alloc_node(cachep, flags, node);
3366 EXPORT_SYMBOL(__kmalloc_node);
3370 * __do_kmalloc - allocate memory
3371 * @size: how many bytes of memory are required.
3372 * @flags: the type of memory to allocate (see kmalloc).
3373 * @caller: function caller for debug tracking of the caller
3375 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3378 struct kmem_cache *cachep;
3380 /* If you want to save a few bytes .text space: replace
3382 * Then kmalloc uses the uninlined functions instead of the inline
3385 cachep = __find_general_cachep(size, flags);
3386 if (unlikely(cachep == NULL))
3388 return __cache_alloc(cachep, flags, caller);
3392 void *__kmalloc(size_t size, gfp_t flags)
3394 #ifndef CONFIG_DEBUG_SLAB
3395 return __do_kmalloc(size, flags, NULL);
3397 return __do_kmalloc(size, flags, __builtin_return_address(0));
3400 EXPORT_SYMBOL(__kmalloc);
3402 #ifdef CONFIG_DEBUG_SLAB
3403 void *__kmalloc_track_caller(size_t size, gfp_t flags, void *caller)
3405 return __do_kmalloc(size, flags, caller);
3407 EXPORT_SYMBOL(__kmalloc_track_caller);
3412 * percpu_depopulate - depopulate per-cpu data for given cpu
3413 * @__pdata: per-cpu data to depopulate
3414 * @cpu: depopulate per-cpu data for this cpu
3416 * Depopulating per-cpu data for a cpu going offline would be a typical
3417 * use case. You need to register a cpu hotplug handler for that purpose.
3419 void percpu_depopulate(void *__pdata, int cpu)
3421 struct percpu_data *pdata = __percpu_disguise(__pdata);
3422 if (pdata->ptrs[cpu]) {
3423 kfree(pdata->ptrs[cpu]);
3424 pdata->ptrs[cpu] = NULL;
3427 EXPORT_SYMBOL_GPL(percpu_depopulate);
3430 * percpu_depopulate_mask - depopulate per-cpu data for some cpu's
3431 * @__pdata: per-cpu data to depopulate
3432 * @mask: depopulate per-cpu data for cpu's selected through mask bits
3434 void __percpu_depopulate_mask(void *__pdata, cpumask_t *mask)
3437 for_each_cpu_mask(cpu, *mask)
3438 percpu_depopulate(__pdata, cpu);
3440 EXPORT_SYMBOL_GPL(__percpu_depopulate_mask);
3443 * percpu_populate - populate per-cpu data for given cpu
3444 * @__pdata: per-cpu data to populate further
3445 * @size: size of per-cpu object
3446 * @gfp: may sleep or not etc.
3447 * @cpu: populate per-data for this cpu
3449 * Populating per-cpu data for a cpu coming online would be a typical
3450 * use case. You need to register a cpu hotplug handler for that purpose.
3451 * Per-cpu object is populated with zeroed buffer.
3453 void *percpu_populate(void *__pdata, size_t size, gfp_t gfp, int cpu)
3455 struct percpu_data *pdata = __percpu_disguise(__pdata);
3456 int node = cpu_to_node(cpu);
3458 BUG_ON(pdata->ptrs[cpu]);
3459 if (node_online(node)) {
3460 /* FIXME: kzalloc_node(size, gfp, node) */
3461 pdata->ptrs[cpu] = kmalloc_node(size, gfp, node);
3462 if (pdata->ptrs[cpu])
3463 memset(pdata->ptrs[cpu], 0, size);
3465 pdata->ptrs[cpu] = kzalloc(size, gfp);
3466 return pdata->ptrs[cpu];
3468 EXPORT_SYMBOL_GPL(percpu_populate);
3471 * percpu_populate_mask - populate per-cpu data for more cpu's
3472 * @__pdata: per-cpu data to populate further
3473 * @size: size of per-cpu object
3474 * @gfp: may sleep or not etc.
3475 * @mask: populate per-cpu data for cpu's selected through mask bits
3477 * Per-cpu objects are populated with zeroed buffers.
3479 int __percpu_populate_mask(void *__pdata, size_t size, gfp_t gfp,
3482 cpumask_t populated = CPU_MASK_NONE;
3485 for_each_cpu_mask(cpu, *mask)
3486 if (unlikely(!percpu_populate(__pdata, size, gfp, cpu))) {
3487 __percpu_depopulate_mask(__pdata, &populated);
3490 cpu_set(cpu, populated);
3493 EXPORT_SYMBOL_GPL(__percpu_populate_mask);
3496 * percpu_alloc_mask - initial setup of per-cpu data
3497 * @size: size of per-cpu object
3498 * @gfp: may sleep or not etc.
3499 * @mask: populate per-data for cpu's selected through mask bits
3501 * Populating per-cpu data for all online cpu's would be a typical use case,
3502 * which is simplified by the percpu_alloc() wrapper.
3503 * Per-cpu objects are populated with zeroed buffers.
3505 void *__percpu_alloc_mask(size_t size, gfp_t gfp, cpumask_t *mask)
3507 void *pdata = kzalloc(sizeof(struct percpu_data), gfp);
3508 void *__pdata = __percpu_disguise(pdata);
3510 if (unlikely(!pdata))
3512 if (likely(!__percpu_populate_mask(__pdata, size, gfp, mask)))
3517 EXPORT_SYMBOL_GPL(__percpu_alloc_mask);
3520 * percpu_free - final cleanup of per-cpu data
3521 * @__pdata: object to clean up
3523 * We simply clean up any per-cpu object left. No need for the client to
3524 * track and specify through a bis mask which per-cpu objects are to free.
3526 void percpu_free(void *__pdata)
3528 __percpu_depopulate_mask(__pdata, &cpu_possible_map);
3529 kfree(__percpu_disguise(__pdata));
3531 EXPORT_SYMBOL_GPL(percpu_free);
3532 #endif /* CONFIG_SMP */
3535 * kmem_cache_free - Deallocate an object
3536 * @cachep: The cache the allocation was from.
3537 * @objp: The previously allocated object.
3539 * Free an object which was previously allocated from this
3542 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3544 unsigned long flags;
3546 BUG_ON(virt_to_cache(objp) != cachep);
3548 local_irq_save(flags);
3549 __cache_free(cachep, objp);
3550 local_irq_restore(flags);
3552 EXPORT_SYMBOL(kmem_cache_free);
3555 * kfree - free previously allocated memory
3556 * @objp: pointer returned by kmalloc.
3558 * If @objp is NULL, no operation is performed.
3560 * Don't free memory not originally allocated by kmalloc()
3561 * or you will run into trouble.
3563 void kfree(const void *objp)
3565 struct kmem_cache *c;
3566 unsigned long flags;
3568 if (unlikely(!objp))
3570 local_irq_save(flags);
3571 kfree_debugcheck(objp);
3572 c = virt_to_cache(objp);
3573 debug_check_no_locks_freed(objp, obj_size(c));
3574 __cache_free(c, (void *)objp);
3575 local_irq_restore(flags);
3577 EXPORT_SYMBOL(kfree);
3579 unsigned int kmem_cache_size(struct kmem_cache *cachep)
3581 return obj_size(cachep);
3583 EXPORT_SYMBOL(kmem_cache_size);
3585 const char *kmem_cache_name(struct kmem_cache *cachep)
3587 return cachep->name;
3589 EXPORT_SYMBOL_GPL(kmem_cache_name);
3592 * This initializes kmem_list3 or resizes varioius caches for all nodes.
3594 static int alloc_kmemlist(struct kmem_cache *cachep)
3597 struct kmem_list3 *l3;
3598 struct array_cache *new_shared;
3599 struct array_cache **new_alien;
3601 for_each_online_node(node) {
3603 new_alien = alloc_alien_cache(node, cachep->limit);
3607 new_shared = alloc_arraycache(node,
3608 cachep->shared*cachep->batchcount,
3611 free_alien_cache(new_alien);
3615 l3 = cachep->nodelists[node];
3617 struct array_cache *shared = l3->shared;
3619 spin_lock_irq(&l3->list_lock);
3622 free_block(cachep, shared->entry,
3623 shared->avail, node);
3625 l3->shared = new_shared;
3627 l3->alien = new_alien;
3630 l3->free_limit = (1 + nr_cpus_node(node)) *
3631 cachep->batchcount + cachep->num;
3632 spin_unlock_irq(&l3->list_lock);
3634 free_alien_cache(new_alien);
3637 l3 = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, node);
3639 free_alien_cache(new_alien);
3644 kmem_list3_init(l3);
3645 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
3646 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
3647 l3->shared = new_shared;
3648 l3->alien = new_alien;
3649 l3->free_limit = (1 + nr_cpus_node(node)) *
3650 cachep->batchcount + cachep->num;
3651 cachep->nodelists[node] = l3;
3656 if (!cachep->next.next) {
3657 /* Cache is not active yet. Roll back what we did */
3660 if (cachep->nodelists[node]) {
3661 l3 = cachep->nodelists[node];
3664 free_alien_cache(l3->alien);
3666 cachep->nodelists[node] = NULL;
3674 struct ccupdate_struct {
3675 struct kmem_cache *cachep;
3676 struct array_cache *new[NR_CPUS];
3679 static void do_ccupdate_local(void *info)
3681 struct ccupdate_struct *new = info;
3682 struct array_cache *old;
3685 old = cpu_cache_get(new->cachep);
3687 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
3688 new->new[smp_processor_id()] = old;
3691 /* Always called with the cache_chain_mutex held */
3692 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3693 int batchcount, int shared)
3695 struct ccupdate_struct new;
3698 memset(&new.new, 0, sizeof(new.new));
3699 for_each_online_cpu(i) {
3700 new.new[i] = alloc_arraycache(cpu_to_node(i), limit,
3703 for (i--; i >= 0; i--)
3708 new.cachep = cachep;
3710 on_each_cpu(do_ccupdate_local, (void *)&new, 1, 1);
3713 cachep->batchcount = batchcount;
3714 cachep->limit = limit;
3715 cachep->shared = shared;
3717 for_each_online_cpu(i) {
3718 struct array_cache *ccold = new.new[i];
3721 spin_lock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3722 free_block(cachep, ccold->entry, ccold->avail, cpu_to_node(i));
3723 spin_unlock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3727 err = alloc_kmemlist(cachep);
3729 printk(KERN_ERR "alloc_kmemlist failed for %s, error %d.\n",
3730 cachep->name, -err);
3736 /* Called with cache_chain_mutex held always */
3737 static void enable_cpucache(struct kmem_cache *cachep)
3743 * The head array serves three purposes:
3744 * - create a LIFO ordering, i.e. return objects that are cache-warm
3745 * - reduce the number of spinlock operations.
3746 * - reduce the number of linked list operations on the slab and
3747 * bufctl chains: array operations are cheaper.
3748 * The numbers are guessed, we should auto-tune as described by
3751 if (cachep->buffer_size > 131072)
3753 else if (cachep->buffer_size > PAGE_SIZE)
3755 else if (cachep->buffer_size > 1024)
3757 else if (cachep->buffer_size > 256)
3763 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3764 * allocation behaviour: Most allocs on one cpu, most free operations
3765 * on another cpu. For these cases, an efficient object passing between
3766 * cpus is necessary. This is provided by a shared array. The array
3767 * replaces Bonwick's magazine layer.
3768 * On uniprocessor, it's functionally equivalent (but less efficient)
3769 * to a larger limit. Thus disabled by default.
3773 if (cachep->buffer_size <= PAGE_SIZE)
3779 * With debugging enabled, large batchcount lead to excessively long
3780 * periods with disabled local interrupts. Limit the batchcount
3785 err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared);
3787 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
3788 cachep->name, -err);
3792 * Drain an array if it contains any elements taking the l3 lock only if
3793 * necessary. Note that the l3 listlock also protects the array_cache
3794 * if drain_array() is used on the shared array.
3796 void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
3797 struct array_cache *ac, int force, int node)
3801 if (!ac || !ac->avail)
3803 if (ac->touched && !force) {
3806 spin_lock_irq(&l3->list_lock);
3808 tofree = force ? ac->avail : (ac->limit + 4) / 5;
3809 if (tofree > ac->avail)
3810 tofree = (ac->avail + 1) / 2;
3811 free_block(cachep, ac->entry, tofree, node);
3812 ac->avail -= tofree;
3813 memmove(ac->entry, &(ac->entry[tofree]),
3814 sizeof(void *) * ac->avail);
3816 spin_unlock_irq(&l3->list_lock);
3821 * cache_reap - Reclaim memory from caches.
3822 * @unused: unused parameter
3824 * Called from workqueue/eventd every few seconds.
3826 * - clear the per-cpu caches for this CPU.
3827 * - return freeable pages to the main free memory pool.
3829 * If we cannot acquire the cache chain mutex then just give up - we'll try
3830 * again on the next iteration.
3832 static void cache_reap(void *unused)
3834 struct kmem_cache *searchp;
3835 struct kmem_list3 *l3;
3836 int node = numa_node_id();
3838 if (!mutex_trylock(&cache_chain_mutex)) {
3839 /* Give up. Setup the next iteration. */
3840 schedule_delayed_work(&__get_cpu_var(reap_work),
3845 list_for_each_entry(searchp, &cache_chain, next) {
3849 * We only take the l3 lock if absolutely necessary and we
3850 * have established with reasonable certainty that
3851 * we can do some work if the lock was obtained.
3853 l3 = searchp->nodelists[node];
3855 reap_alien(searchp, l3);
3857 drain_array(searchp, l3, cpu_cache_get(searchp), 0, node);
3860 * These are racy checks but it does not matter
3861 * if we skip one check or scan twice.
3863 if (time_after(l3->next_reap, jiffies))
3866 l3->next_reap = jiffies + REAPTIMEOUT_LIST3;
3868 drain_array(searchp, l3, l3->shared, 0, node);
3870 if (l3->free_touched)
3871 l3->free_touched = 0;
3875 freed = drain_freelist(searchp, l3, (l3->free_limit +
3876 5 * searchp->num - 1) / (5 * searchp->num));
3877 STATS_ADD_REAPED(searchp, freed);
3883 mutex_unlock(&cache_chain_mutex);
3885 refresh_cpu_vm_stats(smp_processor_id());
3886 /* Set up the next iteration */
3887 schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC);
3890 #ifdef CONFIG_PROC_FS
3892 static void print_slabinfo_header(struct seq_file *m)
3895 * Output format version, so at least we can change it
3896 * without _too_ many complaints.
3899 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
3901 seq_puts(m, "slabinfo - version: 2.1\n");
3903 seq_puts(m, "# name <active_objs> <num_objs> <objsize> "
3904 "<objperslab> <pagesperslab>");
3905 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
3906 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
3908 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
3909 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
3910 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
3915 static void *s_start(struct seq_file *m, loff_t *pos)
3918 struct list_head *p;
3920 mutex_lock(&cache_chain_mutex);
3922 print_slabinfo_header(m);
3923 p = cache_chain.next;
3926 if (p == &cache_chain)
3929 return list_entry(p, struct kmem_cache, next);
3932 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
3934 struct kmem_cache *cachep = p;
3936 return cachep->next.next == &cache_chain ?
3937 NULL : list_entry(cachep->next.next, struct kmem_cache, next);
3940 static void s_stop(struct seq_file *m, void *p)
3942 mutex_unlock(&cache_chain_mutex);
3945 static int s_show(struct seq_file *m, void *p)
3947 struct kmem_cache *cachep = p;
3949 unsigned long active_objs;
3950 unsigned long num_objs;
3951 unsigned long active_slabs = 0;
3952 unsigned long num_slabs, free_objects = 0, shared_avail = 0;
3956 struct kmem_list3 *l3;
3960 for_each_online_node(node) {
3961 l3 = cachep->nodelists[node];
3966 spin_lock_irq(&l3->list_lock);
3968 list_for_each_entry(slabp, &l3->slabs_full, list) {
3969 if (slabp->inuse != cachep->num && !error)
3970 error = "slabs_full accounting error";
3971 active_objs += cachep->num;
3974 list_for_each_entry(slabp, &l3->slabs_partial, list) {
3975 if (slabp->inuse == cachep->num && !error)
3976 error = "slabs_partial inuse accounting error";
3977 if (!slabp->inuse && !error)
3978 error = "slabs_partial/inuse accounting error";
3979 active_objs += slabp->inuse;
3982 list_for_each_entry(slabp, &l3->slabs_free, list) {
3983 if (slabp->inuse && !error)
3984 error = "slabs_free/inuse accounting error";
3987 free_objects += l3->free_objects;
3989 shared_avail += l3->shared->avail;
3991 spin_unlock_irq(&l3->list_lock);
3993 num_slabs += active_slabs;
3994 num_objs = num_slabs * cachep->num;
3995 if (num_objs - active_objs != free_objects && !error)
3996 error = "free_objects accounting error";
3998 name = cachep->name;
4000 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
4002 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
4003 name, active_objs, num_objs, cachep->buffer_size,
4004 cachep->num, (1 << cachep->gfporder));
4005 seq_printf(m, " : tunables %4u %4u %4u",
4006 cachep->limit, cachep->batchcount, cachep->shared);
4007 seq_printf(m, " : slabdata %6lu %6lu %6lu",
4008 active_slabs, num_slabs, shared_avail);
4011 unsigned long high = cachep->high_mark;
4012 unsigned long allocs = cachep->num_allocations;
4013 unsigned long grown = cachep->grown;
4014 unsigned long reaped = cachep->reaped;
4015 unsigned long errors = cachep->errors;
4016 unsigned long max_freeable = cachep->max_freeable;
4017 unsigned long node_allocs = cachep->node_allocs;
4018 unsigned long node_frees = cachep->node_frees;
4019 unsigned long overflows = cachep->node_overflow;
4021 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu \
4022 %4lu %4lu %4lu %4lu %4lu", allocs, high, grown,
4023 reaped, errors, max_freeable, node_allocs,
4024 node_frees, overflows);
4028 unsigned long allochit = atomic_read(&cachep->allochit);
4029 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4030 unsigned long freehit = atomic_read(&cachep->freehit);
4031 unsigned long freemiss = atomic_read(&cachep->freemiss);
4033 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4034 allochit, allocmiss, freehit, freemiss);
4042 * slabinfo_op - iterator that generates /proc/slabinfo
4051 * num-pages-per-slab
4052 * + further values on SMP and with statistics enabled
4055 struct seq_operations slabinfo_op = {
4062 #define MAX_SLABINFO_WRITE 128
4064 * slabinfo_write - Tuning for the slab allocator
4066 * @buffer: user buffer
4067 * @count: data length
4070 ssize_t slabinfo_write(struct file *file, const char __user * buffer,
4071 size_t count, loff_t *ppos)
4073 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4074 int limit, batchcount, shared, res;
4075 struct kmem_cache *cachep;
4077 if (count > MAX_SLABINFO_WRITE)
4079 if (copy_from_user(&kbuf, buffer, count))
4081 kbuf[MAX_SLABINFO_WRITE] = '\0';
4083 tmp = strchr(kbuf, ' ');
4088 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4091 /* Find the cache in the chain of caches. */
4092 mutex_lock(&cache_chain_mutex);
4094 list_for_each_entry(cachep, &cache_chain, next) {
4095 if (!strcmp(cachep->name, kbuf)) {
4096 if (limit < 1 || batchcount < 1 ||
4097 batchcount > limit || shared < 0) {
4100 res = do_tune_cpucache(cachep, limit,
4101 batchcount, shared);
4106 mutex_unlock(&cache_chain_mutex);
4112 #ifdef CONFIG_DEBUG_SLAB_LEAK
4114 static void *leaks_start(struct seq_file *m, loff_t *pos)
4117 struct list_head *p;
4119 mutex_lock(&cache_chain_mutex);
4120 p = cache_chain.next;
4123 if (p == &cache_chain)
4126 return list_entry(p, struct kmem_cache, next);
4129 static inline int add_caller(unsigned long *n, unsigned long v)
4139 unsigned long *q = p + 2 * i;
4153 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4159 static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
4165 for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) {
4166 if (slab_bufctl(s)[i] != BUFCTL_ACTIVE)
4168 if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4173 static void show_symbol(struct seq_file *m, unsigned long address)
4175 #ifdef CONFIG_KALLSYMS
4178 unsigned long offset, size;
4179 char namebuf[KSYM_NAME_LEN+1];
4181 name = kallsyms_lookup(address, &size, &offset, &modname, namebuf);
4184 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4186 seq_printf(m, " [%s]", modname);
4190 seq_printf(m, "%p", (void *)address);
4193 static int leaks_show(struct seq_file *m, void *p)
4195 struct kmem_cache *cachep = p;
4197 struct kmem_list3 *l3;
4199 unsigned long *n = m->private;
4203 if (!(cachep->flags & SLAB_STORE_USER))
4205 if (!(cachep->flags & SLAB_RED_ZONE))
4208 /* OK, we can do it */
4212 for_each_online_node(node) {
4213 l3 = cachep->nodelists[node];
4218 spin_lock_irq(&l3->list_lock);
4220 list_for_each_entry(slabp, &l3->slabs_full, list)
4221 handle_slab(n, cachep, slabp);
4222 list_for_each_entry(slabp, &l3->slabs_partial, list)
4223 handle_slab(n, cachep, slabp);
4224 spin_unlock_irq(&l3->list_lock);
4226 name = cachep->name;
4228 /* Increase the buffer size */
4229 mutex_unlock(&cache_chain_mutex);
4230 m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4232 /* Too bad, we are really out */
4234 mutex_lock(&cache_chain_mutex);
4237 *(unsigned long *)m->private = n[0] * 2;
4239 mutex_lock(&cache_chain_mutex);
4240 /* Now make sure this entry will be retried */
4244 for (i = 0; i < n[1]; i++) {
4245 seq_printf(m, "%s: %lu ", name, n[2*i+3]);
4246 show_symbol(m, n[2*i+2]);
4252 struct seq_operations slabstats_op = {
4253 .start = leaks_start,
4262 * ksize - get the actual amount of memory allocated for a given object
4263 * @objp: Pointer to the object
4265 * kmalloc may internally round up allocations and return more memory
4266 * than requested. ksize() can be used to determine the actual amount of
4267 * memory allocated. The caller may use this additional memory, even though
4268 * a smaller amount of memory was initially specified with the kmalloc call.
4269 * The caller must guarantee that objp points to a valid object previously
4270 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4271 * must not be freed during the duration of the call.
4273 unsigned int ksize(const void *objp)
4275 if (unlikely(objp == NULL))
4278 return obj_size(virt_to_cache(objp));