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 initializations 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 'slab_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/slab.h>
91 #include <linux/poison.h>
92 #include <linux/swap.h>
93 #include <linux/cache.h>
94 #include <linux/interrupt.h>
95 #include <linux/init.h>
96 #include <linux/compiler.h>
97 #include <linux/cpuset.h>
98 #include <linux/proc_fs.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/uaccess.h>
108 #include <linux/nodemask.h>
109 #include <linux/kmemleak.h>
110 #include <linux/mempolicy.h>
111 #include <linux/mutex.h>
112 #include <linux/fault-inject.h>
113 #include <linux/rtmutex.h>
114 #include <linux/reciprocal_div.h>
115 #include <linux/debugobjects.h>
116 #include <linux/kmemcheck.h>
117 #include <linux/memory.h>
118 #include <linux/prefetch.h>
120 #include <net/sock.h>
122 #include <asm/cacheflush.h>
123 #include <asm/tlbflush.h>
124 #include <asm/page.h>
126 #include <trace/events/kmem.h>
128 #include "internal.h"
133 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
134 * 0 for faster, smaller code (especially in the critical paths).
136 * STATS - 1 to collect stats for /proc/slabinfo.
137 * 0 for faster, smaller code (especially in the critical paths).
139 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
142 #ifdef CONFIG_DEBUG_SLAB
145 #define FORCED_DEBUG 1
149 #define FORCED_DEBUG 0
152 /* Shouldn't this be in a header file somewhere? */
153 #define BYTES_PER_WORD sizeof(void *)
154 #define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long))
156 #ifndef ARCH_KMALLOC_FLAGS
157 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
161 * true if a page was allocated from pfmemalloc reserves for network-based
164 static bool pfmemalloc_active __read_mostly
;
169 * Bufctl's are used for linking objs within a slab
172 * This implementation relies on "struct page" for locating the cache &
173 * slab an object belongs to.
174 * This allows the bufctl structure to be small (one int), but limits
175 * the number of objects a slab (not a cache) can contain when off-slab
176 * bufctls are used. The limit is the size of the largest general cache
177 * that does not use off-slab slabs.
178 * For 32bit archs with 4 kB pages, is this 56.
179 * This is not serious, as it is only for large objects, when it is unwise
180 * to have too many per slab.
181 * Note: This limit can be raised by introducing a general cache whose size
182 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
185 typedef unsigned int kmem_bufctl_t
;
186 #define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
187 #define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
188 #define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2)
189 #define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3)
194 * Manages the objs in a slab. Placed either at the beginning of mem allocated
195 * for a slab, or allocated from an general cache.
196 * Slabs are chained into three list: fully used, partial, fully free slabs.
200 struct list_head list
;
201 void *s_mem
; /* including colour offset */
202 unsigned int inuse
; /* num of objs active in slab */
211 * - LIFO ordering, to hand out cache-warm objects from _alloc
212 * - reduce the number of linked list operations
213 * - reduce spinlock operations
215 * The limit is stored in the per-cpu structure to reduce the data cache
222 unsigned int batchcount
;
223 unsigned int touched
;
226 * Must have this definition in here for the proper
227 * alignment of array_cache. Also simplifies accessing
230 * Entries should not be directly dereferenced as
231 * entries belonging to slabs marked pfmemalloc will
232 * have the lower bits set SLAB_OBJ_PFMEMALLOC
236 #define SLAB_OBJ_PFMEMALLOC 1
237 static inline bool is_obj_pfmemalloc(void *objp
)
239 return (unsigned long)objp
& SLAB_OBJ_PFMEMALLOC
;
242 static inline void set_obj_pfmemalloc(void **objp
)
244 *objp
= (void *)((unsigned long)*objp
| SLAB_OBJ_PFMEMALLOC
);
248 static inline void clear_obj_pfmemalloc(void **objp
)
250 *objp
= (void *)((unsigned long)*objp
& ~SLAB_OBJ_PFMEMALLOC
);
254 * bootstrap: The caches do not work without cpuarrays anymore, but the
255 * cpuarrays are allocated from the generic caches...
257 #define BOOT_CPUCACHE_ENTRIES 1
258 struct arraycache_init
{
259 struct array_cache cache
;
260 void *entries
[BOOT_CPUCACHE_ENTRIES
];
264 * Need this for bootstrapping a per node allocator.
266 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
267 static struct kmem_cache_node __initdata init_kmem_cache_node
[NUM_INIT_LISTS
];
268 #define CACHE_CACHE 0
269 #define SIZE_AC MAX_NUMNODES
270 #define SIZE_NODE (2 * MAX_NUMNODES)
272 static int drain_freelist(struct kmem_cache
*cache
,
273 struct kmem_cache_node
*n
, int tofree
);
274 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int len
,
276 static int enable_cpucache(struct kmem_cache
*cachep
, gfp_t gfp
);
277 static void cache_reap(struct work_struct
*unused
);
279 static int slab_early_init
= 1;
281 #define INDEX_AC kmalloc_index(sizeof(struct arraycache_init))
282 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
284 static void kmem_cache_node_init(struct kmem_cache_node
*parent
)
286 INIT_LIST_HEAD(&parent
->slabs_full
);
287 INIT_LIST_HEAD(&parent
->slabs_partial
);
288 INIT_LIST_HEAD(&parent
->slabs_free
);
289 parent
->shared
= NULL
;
290 parent
->alien
= NULL
;
291 parent
->colour_next
= 0;
292 spin_lock_init(&parent
->list_lock
);
293 parent
->free_objects
= 0;
294 parent
->free_touched
= 0;
297 #define MAKE_LIST(cachep, listp, slab, nodeid) \
299 INIT_LIST_HEAD(listp); \
300 list_splice(&(cachep->node[nodeid]->slab), listp); \
303 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
305 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
306 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
307 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
310 #define CFLGS_OFF_SLAB (0x80000000UL)
311 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
313 #define BATCHREFILL_LIMIT 16
315 * Optimization question: fewer reaps means less probability for unnessary
316 * cpucache drain/refill cycles.
318 * OTOH the cpuarrays can contain lots of objects,
319 * which could lock up otherwise freeable slabs.
321 #define REAPTIMEOUT_CPUC (2*HZ)
322 #define REAPTIMEOUT_LIST3 (4*HZ)
325 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
326 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
327 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
328 #define STATS_INC_GROWN(x) ((x)->grown++)
329 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
330 #define STATS_SET_HIGH(x) \
332 if ((x)->num_active > (x)->high_mark) \
333 (x)->high_mark = (x)->num_active; \
335 #define STATS_INC_ERR(x) ((x)->errors++)
336 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
337 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
338 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
339 #define STATS_SET_FREEABLE(x, i) \
341 if ((x)->max_freeable < i) \
342 (x)->max_freeable = i; \
344 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
345 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
346 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
347 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
349 #define STATS_INC_ACTIVE(x) do { } while (0)
350 #define STATS_DEC_ACTIVE(x) do { } while (0)
351 #define STATS_INC_ALLOCED(x) do { } while (0)
352 #define STATS_INC_GROWN(x) do { } while (0)
353 #define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0)
354 #define STATS_SET_HIGH(x) do { } while (0)
355 #define STATS_INC_ERR(x) do { } while (0)
356 #define STATS_INC_NODEALLOCS(x) do { } while (0)
357 #define STATS_INC_NODEFREES(x) do { } while (0)
358 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
359 #define STATS_SET_FREEABLE(x, i) do { } while (0)
360 #define STATS_INC_ALLOCHIT(x) do { } while (0)
361 #define STATS_INC_ALLOCMISS(x) do { } while (0)
362 #define STATS_INC_FREEHIT(x) do { } while (0)
363 #define STATS_INC_FREEMISS(x) do { } while (0)
369 * memory layout of objects:
371 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
372 * the end of an object is aligned with the end of the real
373 * allocation. Catches writes behind the end of the allocation.
374 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
376 * cachep->obj_offset: The real object.
377 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
378 * cachep->size - 1* BYTES_PER_WORD: last caller address
379 * [BYTES_PER_WORD long]
381 static int obj_offset(struct kmem_cache
*cachep
)
383 return cachep
->obj_offset
;
386 static unsigned long long *dbg_redzone1(struct kmem_cache
*cachep
, void *objp
)
388 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
389 return (unsigned long long*) (objp
+ obj_offset(cachep
) -
390 sizeof(unsigned long long));
393 static unsigned long long *dbg_redzone2(struct kmem_cache
*cachep
, void *objp
)
395 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
396 if (cachep
->flags
& SLAB_STORE_USER
)
397 return (unsigned long long *)(objp
+ cachep
->size
-
398 sizeof(unsigned long long) -
400 return (unsigned long long *) (objp
+ cachep
->size
-
401 sizeof(unsigned long long));
404 static void **dbg_userword(struct kmem_cache
*cachep
, void *objp
)
406 BUG_ON(!(cachep
->flags
& SLAB_STORE_USER
));
407 return (void **)(objp
+ cachep
->size
- BYTES_PER_WORD
);
412 #define obj_offset(x) 0
413 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
414 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
415 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
420 * Do not go above this order unless 0 objects fit into the slab or
421 * overridden on the command line.
423 #define SLAB_MAX_ORDER_HI 1
424 #define SLAB_MAX_ORDER_LO 0
425 static int slab_max_order
= SLAB_MAX_ORDER_LO
;
426 static bool slab_max_order_set __initdata
;
428 static inline struct kmem_cache
*virt_to_cache(const void *obj
)
430 struct page
*page
= virt_to_head_page(obj
);
431 return page
->slab_cache
;
434 static inline struct slab
*virt_to_slab(const void *obj
)
436 struct page
*page
= virt_to_head_page(obj
);
438 VM_BUG_ON(!PageSlab(page
));
439 return page
->slab_page
;
442 static inline void *index_to_obj(struct kmem_cache
*cache
, struct slab
*slab
,
445 return slab
->s_mem
+ cache
->size
* idx
;
449 * We want to avoid an expensive divide : (offset / cache->size)
450 * Using the fact that size is a constant for a particular cache,
451 * we can replace (offset / cache->size) by
452 * reciprocal_divide(offset, cache->reciprocal_buffer_size)
454 static inline unsigned int obj_to_index(const struct kmem_cache
*cache
,
455 const struct slab
*slab
, void *obj
)
457 u32 offset
= (obj
- slab
->s_mem
);
458 return reciprocal_divide(offset
, cache
->reciprocal_buffer_size
);
461 static struct arraycache_init initarray_generic
=
462 { {0, BOOT_CPUCACHE_ENTRIES
, 1, 0} };
464 /* internal cache of cache description objs */
465 static struct kmem_cache kmem_cache_boot
= {
467 .limit
= BOOT_CPUCACHE_ENTRIES
,
469 .size
= sizeof(struct kmem_cache
),
470 .name
= "kmem_cache",
473 #define BAD_ALIEN_MAGIC 0x01020304ul
475 #ifdef CONFIG_LOCKDEP
478 * Slab sometimes uses the kmalloc slabs to store the slab headers
479 * for other slabs "off slab".
480 * The locking for this is tricky in that it nests within the locks
481 * of all other slabs in a few places; to deal with this special
482 * locking we put on-slab caches into a separate lock-class.
484 * We set lock class for alien array caches which are up during init.
485 * The lock annotation will be lost if all cpus of a node goes down and
486 * then comes back up during hotplug
488 static struct lock_class_key on_slab_l3_key
;
489 static struct lock_class_key on_slab_alc_key
;
491 static struct lock_class_key debugobj_l3_key
;
492 static struct lock_class_key debugobj_alc_key
;
494 static void slab_set_lock_classes(struct kmem_cache
*cachep
,
495 struct lock_class_key
*l3_key
, struct lock_class_key
*alc_key
,
498 struct array_cache
**alc
;
499 struct kmem_cache_node
*n
;
506 lockdep_set_class(&n
->list_lock
, l3_key
);
509 * FIXME: This check for BAD_ALIEN_MAGIC
510 * should go away when common slab code is taught to
511 * work even without alien caches.
512 * Currently, non NUMA code returns BAD_ALIEN_MAGIC
513 * for alloc_alien_cache,
515 if (!alc
|| (unsigned long)alc
== BAD_ALIEN_MAGIC
)
519 lockdep_set_class(&alc
[r
]->lock
, alc_key
);
523 static void slab_set_debugobj_lock_classes_node(struct kmem_cache
*cachep
, int node
)
525 slab_set_lock_classes(cachep
, &debugobj_l3_key
, &debugobj_alc_key
, node
);
528 static void slab_set_debugobj_lock_classes(struct kmem_cache
*cachep
)
532 for_each_online_node(node
)
533 slab_set_debugobj_lock_classes_node(cachep
, node
);
536 static void init_node_lock_keys(int q
)
543 for (i
= 1; i
<= KMALLOC_SHIFT_HIGH
; i
++) {
544 struct kmem_cache_node
*n
;
545 struct kmem_cache
*cache
= kmalloc_caches
[i
];
551 if (!n
|| OFF_SLAB(cache
))
554 slab_set_lock_classes(cache
, &on_slab_l3_key
,
555 &on_slab_alc_key
, q
);
559 static void on_slab_lock_classes_node(struct kmem_cache
*cachep
, int q
)
561 if (!cachep
->node
[q
])
564 slab_set_lock_classes(cachep
, &on_slab_l3_key
,
565 &on_slab_alc_key
, q
);
568 static inline void on_slab_lock_classes(struct kmem_cache
*cachep
)
572 VM_BUG_ON(OFF_SLAB(cachep
));
574 on_slab_lock_classes_node(cachep
, node
);
577 static inline void init_lock_keys(void)
582 init_node_lock_keys(node
);
585 static void init_node_lock_keys(int q
)
589 static inline void init_lock_keys(void)
593 static inline void on_slab_lock_classes(struct kmem_cache
*cachep
)
597 static inline void on_slab_lock_classes_node(struct kmem_cache
*cachep
, int node
)
601 static void slab_set_debugobj_lock_classes_node(struct kmem_cache
*cachep
, int node
)
605 static void slab_set_debugobj_lock_classes(struct kmem_cache
*cachep
)
610 static DEFINE_PER_CPU(struct delayed_work
, slab_reap_work
);
612 static inline struct array_cache
*cpu_cache_get(struct kmem_cache
*cachep
)
614 return cachep
->array
[smp_processor_id()];
617 static size_t slab_mgmt_size(size_t nr_objs
, size_t align
)
619 return ALIGN(sizeof(struct slab
)+nr_objs
*sizeof(kmem_bufctl_t
), align
);
623 * Calculate the number of objects and left-over bytes for a given buffer size.
625 static void cache_estimate(unsigned long gfporder
, size_t buffer_size
,
626 size_t align
, int flags
, size_t *left_over
,
631 size_t slab_size
= PAGE_SIZE
<< gfporder
;
634 * The slab management structure can be either off the slab or
635 * on it. For the latter case, the memory allocated for a
639 * - One kmem_bufctl_t for each object
640 * - Padding to respect alignment of @align
641 * - @buffer_size bytes for each object
643 * If the slab management structure is off the slab, then the
644 * alignment will already be calculated into the size. Because
645 * the slabs are all pages aligned, the objects will be at the
646 * correct alignment when allocated.
648 if (flags
& CFLGS_OFF_SLAB
) {
650 nr_objs
= slab_size
/ buffer_size
;
652 if (nr_objs
> SLAB_LIMIT
)
653 nr_objs
= SLAB_LIMIT
;
656 * Ignore padding for the initial guess. The padding
657 * is at most @align-1 bytes, and @buffer_size is at
658 * least @align. In the worst case, this result will
659 * be one greater than the number of objects that fit
660 * into the memory allocation when taking the padding
663 nr_objs
= (slab_size
- sizeof(struct slab
)) /
664 (buffer_size
+ sizeof(kmem_bufctl_t
));
667 * This calculated number will be either the right
668 * amount, or one greater than what we want.
670 if (slab_mgmt_size(nr_objs
, align
) + nr_objs
*buffer_size
674 if (nr_objs
> SLAB_LIMIT
)
675 nr_objs
= SLAB_LIMIT
;
677 mgmt_size
= slab_mgmt_size(nr_objs
, align
);
680 *left_over
= slab_size
- nr_objs
*buffer_size
- mgmt_size
;
684 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
686 static void __slab_error(const char *function
, struct kmem_cache
*cachep
,
689 printk(KERN_ERR
"slab error in %s(): cache `%s': %s\n",
690 function
, cachep
->name
, msg
);
692 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
697 * By default on NUMA we use alien caches to stage the freeing of
698 * objects allocated from other nodes. This causes massive memory
699 * inefficiencies when using fake NUMA setup to split memory into a
700 * large number of small nodes, so it can be disabled on the command
704 static int use_alien_caches __read_mostly
= 1;
705 static int __init
noaliencache_setup(char *s
)
707 use_alien_caches
= 0;
710 __setup("noaliencache", noaliencache_setup
);
712 static int __init
slab_max_order_setup(char *str
)
714 get_option(&str
, &slab_max_order
);
715 slab_max_order
= slab_max_order
< 0 ? 0 :
716 min(slab_max_order
, MAX_ORDER
- 1);
717 slab_max_order_set
= true;
721 __setup("slab_max_order=", slab_max_order_setup
);
725 * Special reaping functions for NUMA systems called from cache_reap().
726 * These take care of doing round robin flushing of alien caches (containing
727 * objects freed on different nodes from which they were allocated) and the
728 * flushing of remote pcps by calling drain_node_pages.
730 static DEFINE_PER_CPU(unsigned long, slab_reap_node
);
732 static void init_reap_node(int cpu
)
736 node
= next_node(cpu_to_mem(cpu
), node_online_map
);
737 if (node
== MAX_NUMNODES
)
738 node
= first_node(node_online_map
);
740 per_cpu(slab_reap_node
, cpu
) = node
;
743 static void next_reap_node(void)
745 int node
= __this_cpu_read(slab_reap_node
);
747 node
= next_node(node
, node_online_map
);
748 if (unlikely(node
>= MAX_NUMNODES
))
749 node
= first_node(node_online_map
);
750 __this_cpu_write(slab_reap_node
, node
);
754 #define init_reap_node(cpu) do { } while (0)
755 #define next_reap_node(void) do { } while (0)
759 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
760 * via the workqueue/eventd.
761 * Add the CPU number into the expiration time to minimize the possibility of
762 * the CPUs getting into lockstep and contending for the global cache chain
765 static void start_cpu_timer(int cpu
)
767 struct delayed_work
*reap_work
= &per_cpu(slab_reap_work
, cpu
);
770 * When this gets called from do_initcalls via cpucache_init(),
771 * init_workqueues() has already run, so keventd will be setup
774 if (keventd_up() && reap_work
->work
.func
== NULL
) {
776 INIT_DEFERRABLE_WORK(reap_work
, cache_reap
);
777 schedule_delayed_work_on(cpu
, reap_work
,
778 __round_jiffies_relative(HZ
, cpu
));
782 static struct array_cache
*alloc_arraycache(int node
, int entries
,
783 int batchcount
, gfp_t gfp
)
785 int memsize
= sizeof(void *) * entries
+ sizeof(struct array_cache
);
786 struct array_cache
*nc
= NULL
;
788 nc
= kmalloc_node(memsize
, gfp
, node
);
790 * The array_cache structures contain pointers to free object.
791 * However, when such objects are allocated or transferred to another
792 * cache the pointers are not cleared and they could be counted as
793 * valid references during a kmemleak scan. Therefore, kmemleak must
794 * not scan such objects.
796 kmemleak_no_scan(nc
);
800 nc
->batchcount
= batchcount
;
802 spin_lock_init(&nc
->lock
);
807 static inline bool is_slab_pfmemalloc(struct slab
*slabp
)
809 struct page
*page
= virt_to_page(slabp
->s_mem
);
811 return PageSlabPfmemalloc(page
);
814 /* Clears pfmemalloc_active if no slabs have pfmalloc set */
815 static void recheck_pfmemalloc_active(struct kmem_cache
*cachep
,
816 struct array_cache
*ac
)
818 struct kmem_cache_node
*n
= cachep
->node
[numa_mem_id()];
822 if (!pfmemalloc_active
)
825 spin_lock_irqsave(&n
->list_lock
, flags
);
826 list_for_each_entry(slabp
, &n
->slabs_full
, list
)
827 if (is_slab_pfmemalloc(slabp
))
830 list_for_each_entry(slabp
, &n
->slabs_partial
, list
)
831 if (is_slab_pfmemalloc(slabp
))
834 list_for_each_entry(slabp
, &n
->slabs_free
, list
)
835 if (is_slab_pfmemalloc(slabp
))
838 pfmemalloc_active
= false;
840 spin_unlock_irqrestore(&n
->list_lock
, flags
);
843 static void *__ac_get_obj(struct kmem_cache
*cachep
, struct array_cache
*ac
,
844 gfp_t flags
, bool force_refill
)
847 void *objp
= ac
->entry
[--ac
->avail
];
849 /* Ensure the caller is allowed to use objects from PFMEMALLOC slab */
850 if (unlikely(is_obj_pfmemalloc(objp
))) {
851 struct kmem_cache_node
*n
;
853 if (gfp_pfmemalloc_allowed(flags
)) {
854 clear_obj_pfmemalloc(&objp
);
858 /* The caller cannot use PFMEMALLOC objects, find another one */
859 for (i
= 0; i
< ac
->avail
; i
++) {
860 /* If a !PFMEMALLOC object is found, swap them */
861 if (!is_obj_pfmemalloc(ac
->entry
[i
])) {
863 ac
->entry
[i
] = ac
->entry
[ac
->avail
];
864 ac
->entry
[ac
->avail
] = objp
;
870 * If there are empty slabs on the slabs_free list and we are
871 * being forced to refill the cache, mark this one !pfmemalloc.
873 n
= cachep
->node
[numa_mem_id()];
874 if (!list_empty(&n
->slabs_free
) && force_refill
) {
875 struct slab
*slabp
= virt_to_slab(objp
);
876 ClearPageSlabPfmemalloc(virt_to_head_page(slabp
->s_mem
));
877 clear_obj_pfmemalloc(&objp
);
878 recheck_pfmemalloc_active(cachep
, ac
);
882 /* No !PFMEMALLOC objects available */
890 static inline void *ac_get_obj(struct kmem_cache
*cachep
,
891 struct array_cache
*ac
, gfp_t flags
, bool force_refill
)
895 if (unlikely(sk_memalloc_socks()))
896 objp
= __ac_get_obj(cachep
, ac
, flags
, force_refill
);
898 objp
= ac
->entry
[--ac
->avail
];
903 static void *__ac_put_obj(struct kmem_cache
*cachep
, struct array_cache
*ac
,
906 if (unlikely(pfmemalloc_active
)) {
907 /* Some pfmemalloc slabs exist, check if this is one */
908 struct slab
*slabp
= virt_to_slab(objp
);
909 struct page
*page
= virt_to_head_page(slabp
->s_mem
);
910 if (PageSlabPfmemalloc(page
))
911 set_obj_pfmemalloc(&objp
);
917 static inline void ac_put_obj(struct kmem_cache
*cachep
, struct array_cache
*ac
,
920 if (unlikely(sk_memalloc_socks()))
921 objp
= __ac_put_obj(cachep
, ac
, objp
);
923 ac
->entry
[ac
->avail
++] = objp
;
927 * Transfer objects in one arraycache to another.
928 * Locking must be handled by the caller.
930 * Return the number of entries transferred.
932 static int transfer_objects(struct array_cache
*to
,
933 struct array_cache
*from
, unsigned int max
)
935 /* Figure out how many entries to transfer */
936 int nr
= min3(from
->avail
, max
, to
->limit
- to
->avail
);
941 memcpy(to
->entry
+ to
->avail
, from
->entry
+ from
->avail
-nr
,
951 #define drain_alien_cache(cachep, alien) do { } while (0)
952 #define reap_alien(cachep, n) do { } while (0)
954 static inline struct array_cache
**alloc_alien_cache(int node
, int limit
, gfp_t gfp
)
956 return (struct array_cache
**)BAD_ALIEN_MAGIC
;
959 static inline void free_alien_cache(struct array_cache
**ac_ptr
)
963 static inline int cache_free_alien(struct kmem_cache
*cachep
, void *objp
)
968 static inline void *alternate_node_alloc(struct kmem_cache
*cachep
,
974 static inline void *____cache_alloc_node(struct kmem_cache
*cachep
,
975 gfp_t flags
, int nodeid
)
980 #else /* CONFIG_NUMA */
982 static void *____cache_alloc_node(struct kmem_cache
*, gfp_t
, int);
983 static void *alternate_node_alloc(struct kmem_cache
*, gfp_t
);
985 static struct array_cache
**alloc_alien_cache(int node
, int limit
, gfp_t gfp
)
987 struct array_cache
**ac_ptr
;
988 int memsize
= sizeof(void *) * nr_node_ids
;
993 ac_ptr
= kzalloc_node(memsize
, gfp
, node
);
996 if (i
== node
|| !node_online(i
))
998 ac_ptr
[i
] = alloc_arraycache(node
, limit
, 0xbaadf00d, gfp
);
1000 for (i
--; i
>= 0; i
--)
1010 static void free_alien_cache(struct array_cache
**ac_ptr
)
1021 static void __drain_alien_cache(struct kmem_cache
*cachep
,
1022 struct array_cache
*ac
, int node
)
1024 struct kmem_cache_node
*n
= cachep
->node
[node
];
1027 spin_lock(&n
->list_lock
);
1029 * Stuff objects into the remote nodes shared array first.
1030 * That way we could avoid the overhead of putting the objects
1031 * into the free lists and getting them back later.
1034 transfer_objects(n
->shared
, ac
, ac
->limit
);
1036 free_block(cachep
, ac
->entry
, ac
->avail
, node
);
1038 spin_unlock(&n
->list_lock
);
1043 * Called from cache_reap() to regularly drain alien caches round robin.
1045 static void reap_alien(struct kmem_cache
*cachep
, struct kmem_cache_node
*n
)
1047 int node
= __this_cpu_read(slab_reap_node
);
1050 struct array_cache
*ac
= n
->alien
[node
];
1052 if (ac
&& ac
->avail
&& spin_trylock_irq(&ac
->lock
)) {
1053 __drain_alien_cache(cachep
, ac
, node
);
1054 spin_unlock_irq(&ac
->lock
);
1059 static void drain_alien_cache(struct kmem_cache
*cachep
,
1060 struct array_cache
**alien
)
1063 struct array_cache
*ac
;
1064 unsigned long flags
;
1066 for_each_online_node(i
) {
1069 spin_lock_irqsave(&ac
->lock
, flags
);
1070 __drain_alien_cache(cachep
, ac
, i
);
1071 spin_unlock_irqrestore(&ac
->lock
, flags
);
1076 static inline int cache_free_alien(struct kmem_cache
*cachep
, void *objp
)
1078 int nodeid
= page_to_nid(virt_to_page(objp
));
1079 struct kmem_cache_node
*n
;
1080 struct array_cache
*alien
= NULL
;
1083 node
= numa_mem_id();
1086 * Make sure we are not freeing a object from another node to the array
1087 * cache on this cpu.
1089 if (likely(nodeid
== node
))
1092 n
= cachep
->node
[node
];
1093 STATS_INC_NODEFREES(cachep
);
1094 if (n
->alien
&& n
->alien
[nodeid
]) {
1095 alien
= n
->alien
[nodeid
];
1096 spin_lock(&alien
->lock
);
1097 if (unlikely(alien
->avail
== alien
->limit
)) {
1098 STATS_INC_ACOVERFLOW(cachep
);
1099 __drain_alien_cache(cachep
, alien
, nodeid
);
1101 ac_put_obj(cachep
, alien
, objp
);
1102 spin_unlock(&alien
->lock
);
1104 spin_lock(&(cachep
->node
[nodeid
])->list_lock
);
1105 free_block(cachep
, &objp
, 1, nodeid
);
1106 spin_unlock(&(cachep
->node
[nodeid
])->list_lock
);
1113 * Allocates and initializes node for a node on each slab cache, used for
1114 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node
1115 * will be allocated off-node since memory is not yet online for the new node.
1116 * When hotplugging memory or a cpu, existing node are not replaced if
1119 * Must hold slab_mutex.
1121 static int init_cache_node_node(int node
)
1123 struct kmem_cache
*cachep
;
1124 struct kmem_cache_node
*n
;
1125 const int memsize
= sizeof(struct kmem_cache_node
);
1127 list_for_each_entry(cachep
, &slab_caches
, list
) {
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
->node
[node
]) {
1134 n
= kmalloc_node(memsize
, GFP_KERNEL
, node
);
1137 kmem_cache_node_init(n
);
1138 n
->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. slab_mutex is sufficient
1146 cachep
->node
[node
] = n
;
1149 spin_lock_irq(&cachep
->node
[node
]->list_lock
);
1150 cachep
->node
[node
]->free_limit
=
1151 (1 + nr_cpus_node(node
)) *
1152 cachep
->batchcount
+ cachep
->num
;
1153 spin_unlock_irq(&cachep
->node
[node
]->list_lock
);
1158 static inline int slabs_tofree(struct kmem_cache
*cachep
,
1159 struct kmem_cache_node
*n
)
1161 return (n
->free_objects
+ cachep
->num
- 1) / cachep
->num
;
1164 static void cpuup_canceled(long cpu
)
1166 struct kmem_cache
*cachep
;
1167 struct kmem_cache_node
*n
= NULL
;
1168 int node
= cpu_to_mem(cpu
);
1169 const struct cpumask
*mask
= cpumask_of_node(node
);
1171 list_for_each_entry(cachep
, &slab_caches
, list
) {
1172 struct array_cache
*nc
;
1173 struct array_cache
*shared
;
1174 struct array_cache
**alien
;
1176 /* cpu is dead; no one can alloc from it. */
1177 nc
= cachep
->array
[cpu
];
1178 cachep
->array
[cpu
] = NULL
;
1179 n
= cachep
->node
[node
];
1182 goto free_array_cache
;
1184 spin_lock_irq(&n
->list_lock
);
1186 /* Free limit for this kmem_cache_node */
1187 n
->free_limit
-= cachep
->batchcount
;
1189 free_block(cachep
, nc
->entry
, nc
->avail
, node
);
1191 if (!cpumask_empty(mask
)) {
1192 spin_unlock_irq(&n
->list_lock
);
1193 goto free_array_cache
;
1198 free_block(cachep
, shared
->entry
,
1199 shared
->avail
, node
);
1206 spin_unlock_irq(&n
->list_lock
);
1210 drain_alien_cache(cachep
, alien
);
1211 free_alien_cache(alien
);
1217 * In the previous loop, all the objects were freed to
1218 * the respective cache's slabs, now we can go ahead and
1219 * shrink each nodelist to its limit.
1221 list_for_each_entry(cachep
, &slab_caches
, list
) {
1222 n
= cachep
->node
[node
];
1225 drain_freelist(cachep
, n
, slabs_tofree(cachep
, n
));
1229 static int cpuup_prepare(long cpu
)
1231 struct kmem_cache
*cachep
;
1232 struct kmem_cache_node
*n
= NULL
;
1233 int node
= cpu_to_mem(cpu
);
1237 * We need to do this right in the beginning since
1238 * alloc_arraycache's are going to use this list.
1239 * kmalloc_node allows us to add the slab to the right
1240 * kmem_cache_node and not this cpu's kmem_cache_node
1242 err
= init_cache_node_node(node
);
1247 * Now we can go ahead with allocating the shared arrays and
1250 list_for_each_entry(cachep
, &slab_caches
, list
) {
1251 struct array_cache
*nc
;
1252 struct array_cache
*shared
= NULL
;
1253 struct array_cache
**alien
= NULL
;
1255 nc
= alloc_arraycache(node
, cachep
->limit
,
1256 cachep
->batchcount
, GFP_KERNEL
);
1259 if (cachep
->shared
) {
1260 shared
= alloc_arraycache(node
,
1261 cachep
->shared
* cachep
->batchcount
,
1262 0xbaadf00d, GFP_KERNEL
);
1268 if (use_alien_caches
) {
1269 alien
= alloc_alien_cache(node
, cachep
->limit
, GFP_KERNEL
);
1276 cachep
->array
[cpu
] = nc
;
1277 n
= cachep
->node
[node
];
1280 spin_lock_irq(&n
->list_lock
);
1283 * We are serialised from CPU_DEAD or
1284 * CPU_UP_CANCELLED by the cpucontrol lock
1295 spin_unlock_irq(&n
->list_lock
);
1297 free_alien_cache(alien
);
1298 if (cachep
->flags
& SLAB_DEBUG_OBJECTS
)
1299 slab_set_debugobj_lock_classes_node(cachep
, node
);
1300 else if (!OFF_SLAB(cachep
) &&
1301 !(cachep
->flags
& SLAB_DESTROY_BY_RCU
))
1302 on_slab_lock_classes_node(cachep
, node
);
1304 init_node_lock_keys(node
);
1308 cpuup_canceled(cpu
);
1312 static int cpuup_callback(struct notifier_block
*nfb
,
1313 unsigned long action
, void *hcpu
)
1315 long cpu
= (long)hcpu
;
1319 case CPU_UP_PREPARE
:
1320 case CPU_UP_PREPARE_FROZEN
:
1321 mutex_lock(&slab_mutex
);
1322 err
= cpuup_prepare(cpu
);
1323 mutex_unlock(&slab_mutex
);
1326 case CPU_ONLINE_FROZEN
:
1327 start_cpu_timer(cpu
);
1329 #ifdef CONFIG_HOTPLUG_CPU
1330 case CPU_DOWN_PREPARE
:
1331 case CPU_DOWN_PREPARE_FROZEN
:
1333 * Shutdown cache reaper. Note that the slab_mutex is
1334 * held so that if cache_reap() is invoked it cannot do
1335 * anything expensive but will only modify reap_work
1336 * and reschedule the timer.
1338 cancel_delayed_work_sync(&per_cpu(slab_reap_work
, cpu
));
1339 /* Now the cache_reaper is guaranteed to be not running. */
1340 per_cpu(slab_reap_work
, cpu
).work
.func
= NULL
;
1342 case CPU_DOWN_FAILED
:
1343 case CPU_DOWN_FAILED_FROZEN
:
1344 start_cpu_timer(cpu
);
1347 case CPU_DEAD_FROZEN
:
1349 * Even if all the cpus of a node are down, we don't free the
1350 * kmem_cache_node of any cache. This to avoid a race between
1351 * cpu_down, and a kmalloc allocation from another cpu for
1352 * memory from the node of the cpu going down. The node
1353 * structure is usually allocated from kmem_cache_create() and
1354 * gets destroyed at kmem_cache_destroy().
1358 case CPU_UP_CANCELED
:
1359 case CPU_UP_CANCELED_FROZEN
:
1360 mutex_lock(&slab_mutex
);
1361 cpuup_canceled(cpu
);
1362 mutex_unlock(&slab_mutex
);
1365 return notifier_from_errno(err
);
1368 static struct notifier_block cpucache_notifier
= {
1369 &cpuup_callback
, NULL
, 0
1372 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1374 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1375 * Returns -EBUSY if all objects cannot be drained so that the node is not
1378 * Must hold slab_mutex.
1380 static int __meminit
drain_cache_node_node(int node
)
1382 struct kmem_cache
*cachep
;
1385 list_for_each_entry(cachep
, &slab_caches
, list
) {
1386 struct kmem_cache_node
*n
;
1388 n
= cachep
->node
[node
];
1392 drain_freelist(cachep
, n
, slabs_tofree(cachep
, n
));
1394 if (!list_empty(&n
->slabs_full
) ||
1395 !list_empty(&n
->slabs_partial
)) {
1403 static int __meminit
slab_memory_callback(struct notifier_block
*self
,
1404 unsigned long action
, void *arg
)
1406 struct memory_notify
*mnb
= arg
;
1410 nid
= mnb
->status_change_nid
;
1415 case MEM_GOING_ONLINE
:
1416 mutex_lock(&slab_mutex
);
1417 ret
= init_cache_node_node(nid
);
1418 mutex_unlock(&slab_mutex
);
1420 case MEM_GOING_OFFLINE
:
1421 mutex_lock(&slab_mutex
);
1422 ret
= drain_cache_node_node(nid
);
1423 mutex_unlock(&slab_mutex
);
1427 case MEM_CANCEL_ONLINE
:
1428 case MEM_CANCEL_OFFLINE
:
1432 return notifier_from_errno(ret
);
1434 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1437 * swap the static kmem_cache_node with kmalloced memory
1439 static void __init
init_list(struct kmem_cache
*cachep
, struct kmem_cache_node
*list
,
1442 struct kmem_cache_node
*ptr
;
1444 ptr
= kmalloc_node(sizeof(struct kmem_cache_node
), GFP_NOWAIT
, nodeid
);
1447 memcpy(ptr
, list
, sizeof(struct kmem_cache_node
));
1449 * Do not assume that spinlocks can be initialized via memcpy:
1451 spin_lock_init(&ptr
->list_lock
);
1453 MAKE_ALL_LISTS(cachep
, ptr
, nodeid
);
1454 cachep
->node
[nodeid
] = ptr
;
1458 * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1459 * size of kmem_cache_node.
1461 static void __init
set_up_node(struct kmem_cache
*cachep
, int index
)
1465 for_each_online_node(node
) {
1466 cachep
->node
[node
] = &init_kmem_cache_node
[index
+ node
];
1467 cachep
->node
[node
]->next_reap
= jiffies
+
1469 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
1474 * The memory after the last cpu cache pointer is used for the
1477 static void setup_node_pointer(struct kmem_cache
*cachep
)
1479 cachep
->node
= (struct kmem_cache_node
**)&cachep
->array
[nr_cpu_ids
];
1483 * Initialisation. Called after the page allocator have been initialised and
1484 * before smp_init().
1486 void __init
kmem_cache_init(void)
1490 BUILD_BUG_ON(sizeof(((struct page
*)NULL
)->lru
) <
1491 sizeof(struct rcu_head
));
1492 kmem_cache
= &kmem_cache_boot
;
1493 setup_node_pointer(kmem_cache
);
1495 if (num_possible_nodes() == 1)
1496 use_alien_caches
= 0;
1498 for (i
= 0; i
< NUM_INIT_LISTS
; i
++)
1499 kmem_cache_node_init(&init_kmem_cache_node
[i
]);
1501 set_up_node(kmem_cache
, CACHE_CACHE
);
1504 * Fragmentation resistance on low memory - only use bigger
1505 * page orders on machines with more than 32MB of memory if
1506 * not overridden on the command line.
1508 if (!slab_max_order_set
&& totalram_pages
> (32 << 20) >> PAGE_SHIFT
)
1509 slab_max_order
= SLAB_MAX_ORDER_HI
;
1511 /* Bootstrap is tricky, because several objects are allocated
1512 * from caches that do not exist yet:
1513 * 1) initialize the kmem_cache cache: it contains the struct
1514 * kmem_cache structures of all caches, except kmem_cache itself:
1515 * kmem_cache is statically allocated.
1516 * Initially an __init data area is used for the head array and the
1517 * kmem_cache_node structures, it's replaced with a kmalloc allocated
1518 * array at the end of the bootstrap.
1519 * 2) Create the first kmalloc cache.
1520 * The struct kmem_cache for the new cache is allocated normally.
1521 * An __init data area is used for the head array.
1522 * 3) Create the remaining kmalloc caches, with minimally sized
1524 * 4) Replace the __init data head arrays for kmem_cache and the first
1525 * kmalloc cache with kmalloc allocated arrays.
1526 * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1527 * the other cache's with kmalloc allocated memory.
1528 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1531 /* 1) create the kmem_cache */
1534 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1536 create_boot_cache(kmem_cache
, "kmem_cache",
1537 offsetof(struct kmem_cache
, array
[nr_cpu_ids
]) +
1538 nr_node_ids
* sizeof(struct kmem_cache_node
*),
1539 SLAB_HWCACHE_ALIGN
);
1540 list_add(&kmem_cache
->list
, &slab_caches
);
1542 /* 2+3) create the kmalloc caches */
1545 * Initialize the caches that provide memory for the array cache and the
1546 * kmem_cache_node structures first. Without this, further allocations will
1550 kmalloc_caches
[INDEX_AC
] = create_kmalloc_cache("kmalloc-ac",
1551 kmalloc_size(INDEX_AC
), ARCH_KMALLOC_FLAGS
);
1553 if (INDEX_AC
!= INDEX_NODE
)
1554 kmalloc_caches
[INDEX_NODE
] =
1555 create_kmalloc_cache("kmalloc-node",
1556 kmalloc_size(INDEX_NODE
), ARCH_KMALLOC_FLAGS
);
1558 slab_early_init
= 0;
1560 /* 4) Replace the bootstrap head arrays */
1562 struct array_cache
*ptr
;
1564 ptr
= kmalloc(sizeof(struct arraycache_init
), GFP_NOWAIT
);
1566 memcpy(ptr
, cpu_cache_get(kmem_cache
),
1567 sizeof(struct arraycache_init
));
1569 * Do not assume that spinlocks can be initialized via memcpy:
1571 spin_lock_init(&ptr
->lock
);
1573 kmem_cache
->array
[smp_processor_id()] = ptr
;
1575 ptr
= kmalloc(sizeof(struct arraycache_init
), GFP_NOWAIT
);
1577 BUG_ON(cpu_cache_get(kmalloc_caches
[INDEX_AC
])
1578 != &initarray_generic
.cache
);
1579 memcpy(ptr
, cpu_cache_get(kmalloc_caches
[INDEX_AC
]),
1580 sizeof(struct arraycache_init
));
1582 * Do not assume that spinlocks can be initialized via memcpy:
1584 spin_lock_init(&ptr
->lock
);
1586 kmalloc_caches
[INDEX_AC
]->array
[smp_processor_id()] = ptr
;
1588 /* 5) Replace the bootstrap kmem_cache_node */
1592 for_each_online_node(nid
) {
1593 init_list(kmem_cache
, &init_kmem_cache_node
[CACHE_CACHE
+ nid
], nid
);
1595 init_list(kmalloc_caches
[INDEX_AC
],
1596 &init_kmem_cache_node
[SIZE_AC
+ nid
], nid
);
1598 if (INDEX_AC
!= INDEX_NODE
) {
1599 init_list(kmalloc_caches
[INDEX_NODE
],
1600 &init_kmem_cache_node
[SIZE_NODE
+ nid
], nid
);
1605 create_kmalloc_caches(ARCH_KMALLOC_FLAGS
);
1608 void __init
kmem_cache_init_late(void)
1610 struct kmem_cache
*cachep
;
1614 /* 6) resize the head arrays to their final sizes */
1615 mutex_lock(&slab_mutex
);
1616 list_for_each_entry(cachep
, &slab_caches
, list
)
1617 if (enable_cpucache(cachep
, GFP_NOWAIT
))
1619 mutex_unlock(&slab_mutex
);
1621 /* Annotate slab for lockdep -- annotate the malloc caches */
1628 * Register a cpu startup notifier callback that initializes
1629 * cpu_cache_get for all new cpus
1631 register_cpu_notifier(&cpucache_notifier
);
1635 * Register a memory hotplug callback that initializes and frees
1638 hotplug_memory_notifier(slab_memory_callback
, SLAB_CALLBACK_PRI
);
1642 * The reap timers are started later, with a module init call: That part
1643 * of the kernel is not yet operational.
1647 static int __init
cpucache_init(void)
1652 * Register the timers that return unneeded pages to the page allocator
1654 for_each_online_cpu(cpu
)
1655 start_cpu_timer(cpu
);
1661 __initcall(cpucache_init
);
1663 static noinline
void
1664 slab_out_of_memory(struct kmem_cache
*cachep
, gfp_t gfpflags
, int nodeid
)
1666 struct kmem_cache_node
*n
;
1668 unsigned long flags
;
1672 "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1674 printk(KERN_WARNING
" cache: %s, object size: %d, order: %d\n",
1675 cachep
->name
, cachep
->size
, cachep
->gfporder
);
1677 for_each_online_node(node
) {
1678 unsigned long active_objs
= 0, num_objs
= 0, free_objects
= 0;
1679 unsigned long active_slabs
= 0, num_slabs
= 0;
1681 n
= cachep
->node
[node
];
1685 spin_lock_irqsave(&n
->list_lock
, flags
);
1686 list_for_each_entry(slabp
, &n
->slabs_full
, list
) {
1687 active_objs
+= cachep
->num
;
1690 list_for_each_entry(slabp
, &n
->slabs_partial
, list
) {
1691 active_objs
+= slabp
->inuse
;
1694 list_for_each_entry(slabp
, &n
->slabs_free
, list
)
1697 free_objects
+= n
->free_objects
;
1698 spin_unlock_irqrestore(&n
->list_lock
, flags
);
1700 num_slabs
+= active_slabs
;
1701 num_objs
= num_slabs
* cachep
->num
;
1703 " node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
1704 node
, active_slabs
, num_slabs
, active_objs
, num_objs
,
1710 * Interface to system's page allocator. No need to hold the cache-lock.
1712 * If we requested dmaable memory, we will get it. Even if we
1713 * did not request dmaable memory, we might get it, but that
1714 * would be relatively rare and ignorable.
1716 static struct page
*kmem_getpages(struct kmem_cache
*cachep
, gfp_t flags
,
1722 flags
|= cachep
->allocflags
;
1723 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1724 flags
|= __GFP_RECLAIMABLE
;
1726 page
= alloc_pages_exact_node(nodeid
, flags
| __GFP_NOTRACK
, cachep
->gfporder
);
1728 if (!(flags
& __GFP_NOWARN
) && printk_ratelimit())
1729 slab_out_of_memory(cachep
, flags
, nodeid
);
1733 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1734 if (unlikely(page
->pfmemalloc
))
1735 pfmemalloc_active
= true;
1737 nr_pages
= (1 << cachep
->gfporder
);
1738 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1739 add_zone_page_state(page_zone(page
),
1740 NR_SLAB_RECLAIMABLE
, nr_pages
);
1742 add_zone_page_state(page_zone(page
),
1743 NR_SLAB_UNRECLAIMABLE
, nr_pages
);
1744 __SetPageSlab(page
);
1745 if (page
->pfmemalloc
)
1746 SetPageSlabPfmemalloc(page
);
1747 memcg_bind_pages(cachep
, cachep
->gfporder
);
1749 if (kmemcheck_enabled
&& !(cachep
->flags
& SLAB_NOTRACK
)) {
1750 kmemcheck_alloc_shadow(page
, cachep
->gfporder
, flags
, nodeid
);
1753 kmemcheck_mark_uninitialized_pages(page
, nr_pages
);
1755 kmemcheck_mark_unallocated_pages(page
, nr_pages
);
1762 * Interface to system's page release.
1764 static void kmem_freepages(struct kmem_cache
*cachep
, struct page
*page
)
1766 const unsigned long nr_freed
= (1 << cachep
->gfporder
);
1768 kmemcheck_free_shadow(page
, cachep
->gfporder
);
1770 if (cachep
->flags
& SLAB_RECLAIM_ACCOUNT
)
1771 sub_zone_page_state(page_zone(page
),
1772 NR_SLAB_RECLAIMABLE
, nr_freed
);
1774 sub_zone_page_state(page_zone(page
),
1775 NR_SLAB_UNRECLAIMABLE
, nr_freed
);
1777 BUG_ON(!PageSlab(page
));
1778 __ClearPageSlabPfmemalloc(page
);
1779 __ClearPageSlab(page
);
1781 memcg_release_pages(cachep
, cachep
->gfporder
);
1782 if (current
->reclaim_state
)
1783 current
->reclaim_state
->reclaimed_slab
+= nr_freed
;
1784 __free_memcg_kmem_pages(page
, cachep
->gfporder
);
1787 static void kmem_rcu_free(struct rcu_head
*head
)
1789 struct kmem_cache
*cachep
;
1792 page
= container_of(head
, struct page
, rcu_head
);
1793 cachep
= page
->slab_cache
;
1795 kmem_freepages(cachep
, page
);
1800 #ifdef CONFIG_DEBUG_PAGEALLOC
1801 static void store_stackinfo(struct kmem_cache
*cachep
, unsigned long *addr
,
1802 unsigned long caller
)
1804 int size
= cachep
->object_size
;
1806 addr
= (unsigned long *)&((char *)addr
)[obj_offset(cachep
)];
1808 if (size
< 5 * sizeof(unsigned long))
1811 *addr
++ = 0x12345678;
1813 *addr
++ = smp_processor_id();
1814 size
-= 3 * sizeof(unsigned long);
1816 unsigned long *sptr
= &caller
;
1817 unsigned long svalue
;
1819 while (!kstack_end(sptr
)) {
1821 if (kernel_text_address(svalue
)) {
1823 size
-= sizeof(unsigned long);
1824 if (size
<= sizeof(unsigned long))
1830 *addr
++ = 0x87654321;
1834 static void poison_obj(struct kmem_cache
*cachep
, void *addr
, unsigned char val
)
1836 int size
= cachep
->object_size
;
1837 addr
= &((char *)addr
)[obj_offset(cachep
)];
1839 memset(addr
, val
, size
);
1840 *(unsigned char *)(addr
+ size
- 1) = POISON_END
;
1843 static void dump_line(char *data
, int offset
, int limit
)
1846 unsigned char error
= 0;
1849 printk(KERN_ERR
"%03x: ", offset
);
1850 for (i
= 0; i
< limit
; i
++) {
1851 if (data
[offset
+ i
] != POISON_FREE
) {
1852 error
= data
[offset
+ i
];
1856 print_hex_dump(KERN_CONT
, "", 0, 16, 1,
1857 &data
[offset
], limit
, 1);
1859 if (bad_count
== 1) {
1860 error
^= POISON_FREE
;
1861 if (!(error
& (error
- 1))) {
1862 printk(KERN_ERR
"Single bit error detected. Probably "
1865 printk(KERN_ERR
"Run memtest86+ or a similar memory "
1868 printk(KERN_ERR
"Run a memory test tool.\n");
1877 static void print_objinfo(struct kmem_cache
*cachep
, void *objp
, int lines
)
1882 if (cachep
->flags
& SLAB_RED_ZONE
) {
1883 printk(KERN_ERR
"Redzone: 0x%llx/0x%llx.\n",
1884 *dbg_redzone1(cachep
, objp
),
1885 *dbg_redzone2(cachep
, objp
));
1888 if (cachep
->flags
& SLAB_STORE_USER
) {
1889 printk(KERN_ERR
"Last user: [<%p>](%pSR)\n",
1890 *dbg_userword(cachep
, objp
),
1891 *dbg_userword(cachep
, objp
));
1893 realobj
= (char *)objp
+ obj_offset(cachep
);
1894 size
= cachep
->object_size
;
1895 for (i
= 0; i
< size
&& lines
; i
+= 16, lines
--) {
1898 if (i
+ limit
> size
)
1900 dump_line(realobj
, i
, limit
);
1904 static void check_poison_obj(struct kmem_cache
*cachep
, void *objp
)
1910 realobj
= (char *)objp
+ obj_offset(cachep
);
1911 size
= cachep
->object_size
;
1913 for (i
= 0; i
< size
; i
++) {
1914 char exp
= POISON_FREE
;
1917 if (realobj
[i
] != exp
) {
1923 "Slab corruption (%s): %s start=%p, len=%d\n",
1924 print_tainted(), cachep
->name
, realobj
, size
);
1925 print_objinfo(cachep
, objp
, 0);
1927 /* Hexdump the affected line */
1930 if (i
+ limit
> size
)
1932 dump_line(realobj
, i
, limit
);
1935 /* Limit to 5 lines */
1941 /* Print some data about the neighboring objects, if they
1944 struct slab
*slabp
= virt_to_slab(objp
);
1947 objnr
= obj_to_index(cachep
, slabp
, objp
);
1949 objp
= index_to_obj(cachep
, slabp
, objnr
- 1);
1950 realobj
= (char *)objp
+ obj_offset(cachep
);
1951 printk(KERN_ERR
"Prev obj: start=%p, len=%d\n",
1953 print_objinfo(cachep
, objp
, 2);
1955 if (objnr
+ 1 < cachep
->num
) {
1956 objp
= index_to_obj(cachep
, slabp
, objnr
+ 1);
1957 realobj
= (char *)objp
+ obj_offset(cachep
);
1958 printk(KERN_ERR
"Next obj: start=%p, len=%d\n",
1960 print_objinfo(cachep
, objp
, 2);
1967 static void slab_destroy_debugcheck(struct kmem_cache
*cachep
, struct slab
*slabp
)
1970 for (i
= 0; i
< cachep
->num
; i
++) {
1971 void *objp
= index_to_obj(cachep
, slabp
, i
);
1973 if (cachep
->flags
& SLAB_POISON
) {
1974 #ifdef CONFIG_DEBUG_PAGEALLOC
1975 if (cachep
->size
% PAGE_SIZE
== 0 &&
1977 kernel_map_pages(virt_to_page(objp
),
1978 cachep
->size
/ PAGE_SIZE
, 1);
1980 check_poison_obj(cachep
, objp
);
1982 check_poison_obj(cachep
, objp
);
1985 if (cachep
->flags
& SLAB_RED_ZONE
) {
1986 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
1987 slab_error(cachep
, "start of a freed object "
1989 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
1990 slab_error(cachep
, "end of a freed object "
1996 static void slab_destroy_debugcheck(struct kmem_cache
*cachep
, struct slab
*slabp
)
2002 * slab_destroy - destroy and release all objects in a slab
2003 * @cachep: cache pointer being destroyed
2004 * @slabp: slab pointer being destroyed
2006 * Destroy all the objs in a slab, and release the mem back to the system.
2007 * Before calling the slab must have been unlinked from the cache. The
2008 * cache-lock is not held/needed.
2010 static void slab_destroy(struct kmem_cache
*cachep
, struct slab
*slabp
)
2012 struct page
*page
= virt_to_head_page(slabp
->s_mem
);
2014 slab_destroy_debugcheck(cachep
, slabp
);
2015 if (unlikely(cachep
->flags
& SLAB_DESTROY_BY_RCU
)) {
2016 struct rcu_head
*head
;
2019 * RCU free overloads the RCU head over the LRU.
2020 * slab_page has been overloeaded over the LRU,
2021 * however it is not used from now on so that
2022 * we can use it safely.
2024 head
= (void *)&page
->rcu_head
;
2025 call_rcu(head
, kmem_rcu_free
);
2028 kmem_freepages(cachep
, page
);
2032 * From now on, we don't use slab management
2033 * although actual page can be freed in rcu context
2035 if (OFF_SLAB(cachep
))
2036 kmem_cache_free(cachep
->slabp_cache
, slabp
);
2040 * calculate_slab_order - calculate size (page order) of slabs
2041 * @cachep: pointer to the cache that is being created
2042 * @size: size of objects to be created in this cache.
2043 * @align: required alignment for the objects.
2044 * @flags: slab allocation flags
2046 * Also calculates the number of objects per slab.
2048 * This could be made much more intelligent. For now, try to avoid using
2049 * high order pages for slabs. When the gfp() functions are more friendly
2050 * towards high-order requests, this should be changed.
2052 static size_t calculate_slab_order(struct kmem_cache
*cachep
,
2053 size_t size
, size_t align
, unsigned long flags
)
2055 unsigned long offslab_limit
;
2056 size_t left_over
= 0;
2059 for (gfporder
= 0; gfporder
<= KMALLOC_MAX_ORDER
; gfporder
++) {
2063 cache_estimate(gfporder
, size
, align
, flags
, &remainder
, &num
);
2067 if (flags
& CFLGS_OFF_SLAB
) {
2069 * Max number of objs-per-slab for caches which
2070 * use off-slab slabs. Needed to avoid a possible
2071 * looping condition in cache_grow().
2073 offslab_limit
= size
- sizeof(struct slab
);
2074 offslab_limit
/= sizeof(kmem_bufctl_t
);
2076 if (num
> offslab_limit
)
2080 /* Found something acceptable - save it away */
2082 cachep
->gfporder
= gfporder
;
2083 left_over
= remainder
;
2086 * A VFS-reclaimable slab tends to have most allocations
2087 * as GFP_NOFS and we really don't want to have to be allocating
2088 * higher-order pages when we are unable to shrink dcache.
2090 if (flags
& SLAB_RECLAIM_ACCOUNT
)
2094 * Large number of objects is good, but very large slabs are
2095 * currently bad for the gfp()s.
2097 if (gfporder
>= slab_max_order
)
2101 * Acceptable internal fragmentation?
2103 if (left_over
* 8 <= (PAGE_SIZE
<< gfporder
))
2109 static int __init_refok
setup_cpu_cache(struct kmem_cache
*cachep
, gfp_t gfp
)
2111 if (slab_state
>= FULL
)
2112 return enable_cpucache(cachep
, gfp
);
2114 if (slab_state
== DOWN
) {
2116 * Note: Creation of first cache (kmem_cache).
2117 * The setup_node is taken care
2118 * of by the caller of __kmem_cache_create
2120 cachep
->array
[smp_processor_id()] = &initarray_generic
.cache
;
2121 slab_state
= PARTIAL
;
2122 } else if (slab_state
== PARTIAL
) {
2124 * Note: the second kmem_cache_create must create the cache
2125 * that's used by kmalloc(24), otherwise the creation of
2126 * further caches will BUG().
2128 cachep
->array
[smp_processor_id()] = &initarray_generic
.cache
;
2131 * If the cache that's used by kmalloc(sizeof(kmem_cache_node)) is
2132 * the second cache, then we need to set up all its node/,
2133 * otherwise the creation of further caches will BUG().
2135 set_up_node(cachep
, SIZE_AC
);
2136 if (INDEX_AC
== INDEX_NODE
)
2137 slab_state
= PARTIAL_NODE
;
2139 slab_state
= PARTIAL_ARRAYCACHE
;
2141 /* Remaining boot caches */
2142 cachep
->array
[smp_processor_id()] =
2143 kmalloc(sizeof(struct arraycache_init
), gfp
);
2145 if (slab_state
== PARTIAL_ARRAYCACHE
) {
2146 set_up_node(cachep
, SIZE_NODE
);
2147 slab_state
= PARTIAL_NODE
;
2150 for_each_online_node(node
) {
2151 cachep
->node
[node
] =
2152 kmalloc_node(sizeof(struct kmem_cache_node
),
2154 BUG_ON(!cachep
->node
[node
]);
2155 kmem_cache_node_init(cachep
->node
[node
]);
2159 cachep
->node
[numa_mem_id()]->next_reap
=
2160 jiffies
+ REAPTIMEOUT_LIST3
+
2161 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
2163 cpu_cache_get(cachep
)->avail
= 0;
2164 cpu_cache_get(cachep
)->limit
= BOOT_CPUCACHE_ENTRIES
;
2165 cpu_cache_get(cachep
)->batchcount
= 1;
2166 cpu_cache_get(cachep
)->touched
= 0;
2167 cachep
->batchcount
= 1;
2168 cachep
->limit
= BOOT_CPUCACHE_ENTRIES
;
2173 * __kmem_cache_create - Create a cache.
2174 * @cachep: cache management descriptor
2175 * @flags: SLAB flags
2177 * Returns a ptr to the cache on success, NULL on failure.
2178 * Cannot be called within a int, but can be interrupted.
2179 * The @ctor is run when new pages are allocated by the cache.
2183 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2184 * to catch references to uninitialised memory.
2186 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2187 * for buffer overruns.
2189 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2190 * cacheline. This can be beneficial if you're counting cycles as closely
2194 __kmem_cache_create (struct kmem_cache
*cachep
, unsigned long flags
)
2196 size_t left_over
, slab_size
, ralign
;
2199 size_t size
= cachep
->size
;
2204 * Enable redzoning and last user accounting, except for caches with
2205 * large objects, if the increased size would increase the object size
2206 * above the next power of two: caches with object sizes just above a
2207 * power of two have a significant amount of internal fragmentation.
2209 if (size
< 4096 || fls(size
- 1) == fls(size
-1 + REDZONE_ALIGN
+
2210 2 * sizeof(unsigned long long)))
2211 flags
|= SLAB_RED_ZONE
| SLAB_STORE_USER
;
2212 if (!(flags
& SLAB_DESTROY_BY_RCU
))
2213 flags
|= SLAB_POISON
;
2215 if (flags
& SLAB_DESTROY_BY_RCU
)
2216 BUG_ON(flags
& SLAB_POISON
);
2220 * Check that size is in terms of words. This is needed to avoid
2221 * unaligned accesses for some archs when redzoning is used, and makes
2222 * sure any on-slab bufctl's are also correctly aligned.
2224 if (size
& (BYTES_PER_WORD
- 1)) {
2225 size
+= (BYTES_PER_WORD
- 1);
2226 size
&= ~(BYTES_PER_WORD
- 1);
2230 * Redzoning and user store require word alignment or possibly larger.
2231 * Note this will be overridden by architecture or caller mandated
2232 * alignment if either is greater than BYTES_PER_WORD.
2234 if (flags
& SLAB_STORE_USER
)
2235 ralign
= BYTES_PER_WORD
;
2237 if (flags
& SLAB_RED_ZONE
) {
2238 ralign
= REDZONE_ALIGN
;
2239 /* If redzoning, ensure that the second redzone is suitably
2240 * aligned, by adjusting the object size accordingly. */
2241 size
+= REDZONE_ALIGN
- 1;
2242 size
&= ~(REDZONE_ALIGN
- 1);
2245 /* 3) caller mandated alignment */
2246 if (ralign
< cachep
->align
) {
2247 ralign
= cachep
->align
;
2249 /* disable debug if necessary */
2250 if (ralign
> __alignof__(unsigned long long))
2251 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
2255 cachep
->align
= ralign
;
2257 if (slab_is_available())
2262 setup_node_pointer(cachep
);
2266 * Both debugging options require word-alignment which is calculated
2269 if (flags
& SLAB_RED_ZONE
) {
2270 /* add space for red zone words */
2271 cachep
->obj_offset
+= sizeof(unsigned long long);
2272 size
+= 2 * sizeof(unsigned long long);
2274 if (flags
& SLAB_STORE_USER
) {
2275 /* user store requires one word storage behind the end of
2276 * the real object. But if the second red zone needs to be
2277 * aligned to 64 bits, we must allow that much space.
2279 if (flags
& SLAB_RED_ZONE
)
2280 size
+= REDZONE_ALIGN
;
2282 size
+= BYTES_PER_WORD
;
2284 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2285 if (size
>= kmalloc_size(INDEX_NODE
+ 1)
2286 && cachep
->object_size
> cache_line_size()
2287 && ALIGN(size
, cachep
->align
) < PAGE_SIZE
) {
2288 cachep
->obj_offset
+= PAGE_SIZE
- ALIGN(size
, cachep
->align
);
2295 * Determine if the slab management is 'on' or 'off' slab.
2296 * (bootstrapping cannot cope with offslab caches so don't do
2297 * it too early on. Always use on-slab management when
2298 * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
2300 if ((size
>= (PAGE_SIZE
>> 3)) && !slab_early_init
&&
2301 !(flags
& SLAB_NOLEAKTRACE
))
2303 * Size is large, assume best to place the slab management obj
2304 * off-slab (should allow better packing of objs).
2306 flags
|= CFLGS_OFF_SLAB
;
2308 size
= ALIGN(size
, cachep
->align
);
2310 left_over
= calculate_slab_order(cachep
, size
, cachep
->align
, flags
);
2315 slab_size
= ALIGN(cachep
->num
* sizeof(kmem_bufctl_t
)
2316 + sizeof(struct slab
), cachep
->align
);
2319 * If the slab has been placed off-slab, and we have enough space then
2320 * move it on-slab. This is at the expense of any extra colouring.
2322 if (flags
& CFLGS_OFF_SLAB
&& left_over
>= slab_size
) {
2323 flags
&= ~CFLGS_OFF_SLAB
;
2324 left_over
-= slab_size
;
2327 if (flags
& CFLGS_OFF_SLAB
) {
2328 /* really off slab. No need for manual alignment */
2330 cachep
->num
* sizeof(kmem_bufctl_t
) + sizeof(struct slab
);
2332 #ifdef CONFIG_PAGE_POISONING
2333 /* If we're going to use the generic kernel_map_pages()
2334 * poisoning, then it's going to smash the contents of
2335 * the redzone and userword anyhow, so switch them off.
2337 if (size
% PAGE_SIZE
== 0 && flags
& SLAB_POISON
)
2338 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
2342 cachep
->colour_off
= cache_line_size();
2343 /* Offset must be a multiple of the alignment. */
2344 if (cachep
->colour_off
< cachep
->align
)
2345 cachep
->colour_off
= cachep
->align
;
2346 cachep
->colour
= left_over
/ cachep
->colour_off
;
2347 cachep
->slab_size
= slab_size
;
2348 cachep
->flags
= flags
;
2349 cachep
->allocflags
= __GFP_COMP
;
2350 if (CONFIG_ZONE_DMA_FLAG
&& (flags
& SLAB_CACHE_DMA
))
2351 cachep
->allocflags
|= GFP_DMA
;
2352 cachep
->size
= size
;
2353 cachep
->reciprocal_buffer_size
= reciprocal_value(size
);
2355 if (flags
& CFLGS_OFF_SLAB
) {
2356 cachep
->slabp_cache
= kmalloc_slab(slab_size
, 0u);
2358 * This is a possibility for one of the malloc_sizes caches.
2359 * But since we go off slab only for object size greater than
2360 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2361 * this should not happen at all.
2362 * But leave a BUG_ON for some lucky dude.
2364 BUG_ON(ZERO_OR_NULL_PTR(cachep
->slabp_cache
));
2367 err
= setup_cpu_cache(cachep
, gfp
);
2369 __kmem_cache_shutdown(cachep
);
2373 if (flags
& SLAB_DEBUG_OBJECTS
) {
2375 * Would deadlock through slab_destroy()->call_rcu()->
2376 * debug_object_activate()->kmem_cache_alloc().
2378 WARN_ON_ONCE(flags
& SLAB_DESTROY_BY_RCU
);
2380 slab_set_debugobj_lock_classes(cachep
);
2381 } else if (!OFF_SLAB(cachep
) && !(flags
& SLAB_DESTROY_BY_RCU
))
2382 on_slab_lock_classes(cachep
);
2388 static void check_irq_off(void)
2390 BUG_ON(!irqs_disabled());
2393 static void check_irq_on(void)
2395 BUG_ON(irqs_disabled());
2398 static void check_spinlock_acquired(struct kmem_cache
*cachep
)
2402 assert_spin_locked(&cachep
->node
[numa_mem_id()]->list_lock
);
2406 static void check_spinlock_acquired_node(struct kmem_cache
*cachep
, int node
)
2410 assert_spin_locked(&cachep
->node
[node
]->list_lock
);
2415 #define check_irq_off() do { } while(0)
2416 #define check_irq_on() do { } while(0)
2417 #define check_spinlock_acquired(x) do { } while(0)
2418 #define check_spinlock_acquired_node(x, y) do { } while(0)
2421 static void drain_array(struct kmem_cache
*cachep
, struct kmem_cache_node
*n
,
2422 struct array_cache
*ac
,
2423 int force
, int node
);
2425 static void do_drain(void *arg
)
2427 struct kmem_cache
*cachep
= arg
;
2428 struct array_cache
*ac
;
2429 int node
= numa_mem_id();
2432 ac
= cpu_cache_get(cachep
);
2433 spin_lock(&cachep
->node
[node
]->list_lock
);
2434 free_block(cachep
, ac
->entry
, ac
->avail
, node
);
2435 spin_unlock(&cachep
->node
[node
]->list_lock
);
2439 static void drain_cpu_caches(struct kmem_cache
*cachep
)
2441 struct kmem_cache_node
*n
;
2444 on_each_cpu(do_drain
, cachep
, 1);
2446 for_each_online_node(node
) {
2447 n
= cachep
->node
[node
];
2449 drain_alien_cache(cachep
, n
->alien
);
2452 for_each_online_node(node
) {
2453 n
= cachep
->node
[node
];
2455 drain_array(cachep
, n
, n
->shared
, 1, node
);
2460 * Remove slabs from the list of free slabs.
2461 * Specify the number of slabs to drain in tofree.
2463 * Returns the actual number of slabs released.
2465 static int drain_freelist(struct kmem_cache
*cache
,
2466 struct kmem_cache_node
*n
, int tofree
)
2468 struct list_head
*p
;
2473 while (nr_freed
< tofree
&& !list_empty(&n
->slabs_free
)) {
2475 spin_lock_irq(&n
->list_lock
);
2476 p
= n
->slabs_free
.prev
;
2477 if (p
== &n
->slabs_free
) {
2478 spin_unlock_irq(&n
->list_lock
);
2482 slabp
= list_entry(p
, struct slab
, list
);
2484 BUG_ON(slabp
->inuse
);
2486 list_del(&slabp
->list
);
2488 * Safe to drop the lock. The slab is no longer linked
2491 n
->free_objects
-= cache
->num
;
2492 spin_unlock_irq(&n
->list_lock
);
2493 slab_destroy(cache
, slabp
);
2500 /* Called with slab_mutex held to protect against cpu hotplug */
2501 static int __cache_shrink(struct kmem_cache
*cachep
)
2504 struct kmem_cache_node
*n
;
2506 drain_cpu_caches(cachep
);
2509 for_each_online_node(i
) {
2510 n
= cachep
->node
[i
];
2514 drain_freelist(cachep
, n
, slabs_tofree(cachep
, n
));
2516 ret
+= !list_empty(&n
->slabs_full
) ||
2517 !list_empty(&n
->slabs_partial
);
2519 return (ret
? 1 : 0);
2523 * kmem_cache_shrink - Shrink a cache.
2524 * @cachep: The cache to shrink.
2526 * Releases as many slabs as possible for a cache.
2527 * To help debugging, a zero exit status indicates all slabs were released.
2529 int kmem_cache_shrink(struct kmem_cache
*cachep
)
2532 BUG_ON(!cachep
|| in_interrupt());
2535 mutex_lock(&slab_mutex
);
2536 ret
= __cache_shrink(cachep
);
2537 mutex_unlock(&slab_mutex
);
2541 EXPORT_SYMBOL(kmem_cache_shrink
);
2543 int __kmem_cache_shutdown(struct kmem_cache
*cachep
)
2546 struct kmem_cache_node
*n
;
2547 int rc
= __cache_shrink(cachep
);
2552 for_each_online_cpu(i
)
2553 kfree(cachep
->array
[i
]);
2555 /* NUMA: free the node structures */
2556 for_each_online_node(i
) {
2557 n
= cachep
->node
[i
];
2560 free_alien_cache(n
->alien
);
2568 * Get the memory for a slab management obj.
2569 * For a slab cache when the slab descriptor is off-slab, slab descriptors
2570 * always come from malloc_sizes caches. The slab descriptor cannot
2571 * come from the same cache which is getting created because,
2572 * when we are searching for an appropriate cache for these
2573 * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2574 * If we are creating a malloc_sizes cache here it would not be visible to
2575 * kmem_find_general_cachep till the initialization is complete.
2576 * Hence we cannot have slabp_cache same as the original cache.
2578 static struct slab
*alloc_slabmgmt(struct kmem_cache
*cachep
,
2579 struct page
*page
, int colour_off
,
2580 gfp_t local_flags
, int nodeid
)
2583 void *addr
= page_address(page
);
2585 if (OFF_SLAB(cachep
)) {
2586 /* Slab management obj is off-slab. */
2587 slabp
= kmem_cache_alloc_node(cachep
->slabp_cache
,
2588 local_flags
, nodeid
);
2590 * If the first object in the slab is leaked (it's allocated
2591 * but no one has a reference to it), we want to make sure
2592 * kmemleak does not treat the ->s_mem pointer as a reference
2593 * to the object. Otherwise we will not report the leak.
2595 kmemleak_scan_area(&slabp
->list
, sizeof(struct list_head
),
2600 slabp
= addr
+ colour_off
;
2601 colour_off
+= cachep
->slab_size
;
2604 slabp
->s_mem
= addr
+ colour_off
;
2609 static inline kmem_bufctl_t
*slab_bufctl(struct slab
*slabp
)
2611 return (kmem_bufctl_t
*) (slabp
+ 1);
2614 static void cache_init_objs(struct kmem_cache
*cachep
,
2619 for (i
= 0; i
< cachep
->num
; i
++) {
2620 void *objp
= index_to_obj(cachep
, slabp
, i
);
2622 /* need to poison the objs? */
2623 if (cachep
->flags
& SLAB_POISON
)
2624 poison_obj(cachep
, objp
, POISON_FREE
);
2625 if (cachep
->flags
& SLAB_STORE_USER
)
2626 *dbg_userword(cachep
, objp
) = NULL
;
2628 if (cachep
->flags
& SLAB_RED_ZONE
) {
2629 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2630 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2633 * Constructors are not allowed to allocate memory from the same
2634 * cache which they are a constructor for. Otherwise, deadlock.
2635 * They must also be threaded.
2637 if (cachep
->ctor
&& !(cachep
->flags
& SLAB_POISON
))
2638 cachep
->ctor(objp
+ obj_offset(cachep
));
2640 if (cachep
->flags
& SLAB_RED_ZONE
) {
2641 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
2642 slab_error(cachep
, "constructor overwrote the"
2643 " end of an object");
2644 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
2645 slab_error(cachep
, "constructor overwrote the"
2646 " start of an object");
2648 if ((cachep
->size
% PAGE_SIZE
) == 0 &&
2649 OFF_SLAB(cachep
) && cachep
->flags
& SLAB_POISON
)
2650 kernel_map_pages(virt_to_page(objp
),
2651 cachep
->size
/ PAGE_SIZE
, 0);
2656 slab_bufctl(slabp
)[i
] = i
+ 1;
2658 slab_bufctl(slabp
)[i
- 1] = BUFCTL_END
;
2661 static void kmem_flagcheck(struct kmem_cache
*cachep
, gfp_t flags
)
2663 if (CONFIG_ZONE_DMA_FLAG
) {
2664 if (flags
& GFP_DMA
)
2665 BUG_ON(!(cachep
->allocflags
& GFP_DMA
));
2667 BUG_ON(cachep
->allocflags
& GFP_DMA
);
2671 static void *slab_get_obj(struct kmem_cache
*cachep
, struct slab
*slabp
,
2674 void *objp
= index_to_obj(cachep
, slabp
, slabp
->free
);
2678 next
= slab_bufctl(slabp
)[slabp
->free
];
2680 slab_bufctl(slabp
)[slabp
->free
] = BUFCTL_FREE
;
2681 WARN_ON(page_to_nid(virt_to_page(objp
)) != nodeid
);
2688 static void slab_put_obj(struct kmem_cache
*cachep
, struct slab
*slabp
,
2689 void *objp
, int nodeid
)
2691 unsigned int objnr
= obj_to_index(cachep
, slabp
, objp
);
2694 /* Verify that the slab belongs to the intended node */
2695 WARN_ON(page_to_nid(virt_to_page(objp
)) != nodeid
);
2697 if (slab_bufctl(slabp
)[objnr
] + 1 <= SLAB_LIMIT
+ 1) {
2698 printk(KERN_ERR
"slab: double free detected in cache "
2699 "'%s', objp %p\n", cachep
->name
, objp
);
2703 slab_bufctl(slabp
)[objnr
] = slabp
->free
;
2704 slabp
->free
= objnr
;
2709 * Map pages beginning at addr to the given cache and slab. This is required
2710 * for the slab allocator to be able to lookup the cache and slab of a
2711 * virtual address for kfree, ksize, and slab debugging.
2713 static void slab_map_pages(struct kmem_cache
*cache
, struct slab
*slab
,
2716 page
->slab_cache
= cache
;
2717 page
->slab_page
= slab
;
2721 * Grow (by 1) the number of slabs within a cache. This is called by
2722 * kmem_cache_alloc() when there are no active objs left in a cache.
2724 static int cache_grow(struct kmem_cache
*cachep
,
2725 gfp_t flags
, int nodeid
, struct page
*page
)
2730 struct kmem_cache_node
*n
;
2733 * Be lazy and only check for valid flags here, keeping it out of the
2734 * critical path in kmem_cache_alloc().
2736 BUG_ON(flags
& GFP_SLAB_BUG_MASK
);
2737 local_flags
= flags
& (GFP_CONSTRAINT_MASK
|GFP_RECLAIM_MASK
);
2739 /* Take the node list lock to change the colour_next on this node */
2741 n
= cachep
->node
[nodeid
];
2742 spin_lock(&n
->list_lock
);
2744 /* Get colour for the slab, and cal the next value. */
2745 offset
= n
->colour_next
;
2747 if (n
->colour_next
>= cachep
->colour
)
2749 spin_unlock(&n
->list_lock
);
2751 offset
*= cachep
->colour_off
;
2753 if (local_flags
& __GFP_WAIT
)
2757 * The test for missing atomic flag is performed here, rather than
2758 * the more obvious place, simply to reduce the critical path length
2759 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2760 * will eventually be caught here (where it matters).
2762 kmem_flagcheck(cachep
, flags
);
2765 * Get mem for the objs. Attempt to allocate a physical page from
2769 page
= kmem_getpages(cachep
, local_flags
, nodeid
);
2773 /* Get slab management. */
2774 slabp
= alloc_slabmgmt(cachep
, page
, offset
,
2775 local_flags
& ~GFP_CONSTRAINT_MASK
, nodeid
);
2779 slab_map_pages(cachep
, slabp
, page
);
2781 cache_init_objs(cachep
, slabp
);
2783 if (local_flags
& __GFP_WAIT
)
2784 local_irq_disable();
2786 spin_lock(&n
->list_lock
);
2788 /* Make slab active. */
2789 list_add_tail(&slabp
->list
, &(n
->slabs_free
));
2790 STATS_INC_GROWN(cachep
);
2791 n
->free_objects
+= cachep
->num
;
2792 spin_unlock(&n
->list_lock
);
2795 kmem_freepages(cachep
, page
);
2797 if (local_flags
& __GFP_WAIT
)
2798 local_irq_disable();
2805 * Perform extra freeing checks:
2806 * - detect bad pointers.
2807 * - POISON/RED_ZONE checking
2809 static void kfree_debugcheck(const void *objp
)
2811 if (!virt_addr_valid(objp
)) {
2812 printk(KERN_ERR
"kfree_debugcheck: out of range ptr %lxh.\n",
2813 (unsigned long)objp
);
2818 static inline void verify_redzone_free(struct kmem_cache
*cache
, void *obj
)
2820 unsigned long long redzone1
, redzone2
;
2822 redzone1
= *dbg_redzone1(cache
, obj
);
2823 redzone2
= *dbg_redzone2(cache
, obj
);
2828 if (redzone1
== RED_ACTIVE
&& redzone2
== RED_ACTIVE
)
2831 if (redzone1
== RED_INACTIVE
&& redzone2
== RED_INACTIVE
)
2832 slab_error(cache
, "double free detected");
2834 slab_error(cache
, "memory outside object was overwritten");
2836 printk(KERN_ERR
"%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
2837 obj
, redzone1
, redzone2
);
2840 static void *cache_free_debugcheck(struct kmem_cache
*cachep
, void *objp
,
2841 unsigned long caller
)
2846 BUG_ON(virt_to_cache(objp
) != cachep
);
2848 objp
-= obj_offset(cachep
);
2849 kfree_debugcheck(objp
);
2850 slabp
= virt_to_slab(objp
);
2852 if (cachep
->flags
& SLAB_RED_ZONE
) {
2853 verify_redzone_free(cachep
, objp
);
2854 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2855 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2857 if (cachep
->flags
& SLAB_STORE_USER
)
2858 *dbg_userword(cachep
, objp
) = (void *)caller
;
2860 objnr
= obj_to_index(cachep
, slabp
, objp
);
2862 BUG_ON(objnr
>= cachep
->num
);
2863 BUG_ON(objp
!= index_to_obj(cachep
, slabp
, objnr
));
2865 #ifdef CONFIG_DEBUG_SLAB_LEAK
2866 slab_bufctl(slabp
)[objnr
] = BUFCTL_FREE
;
2868 if (cachep
->flags
& SLAB_POISON
) {
2869 #ifdef CONFIG_DEBUG_PAGEALLOC
2870 if ((cachep
->size
% PAGE_SIZE
)==0 && OFF_SLAB(cachep
)) {
2871 store_stackinfo(cachep
, objp
, caller
);
2872 kernel_map_pages(virt_to_page(objp
),
2873 cachep
->size
/ PAGE_SIZE
, 0);
2875 poison_obj(cachep
, objp
, POISON_FREE
);
2878 poison_obj(cachep
, objp
, POISON_FREE
);
2884 static void check_slabp(struct kmem_cache
*cachep
, struct slab
*slabp
)
2889 /* Check slab's freelist to see if this obj is there. */
2890 for (i
= slabp
->free
; i
!= BUFCTL_END
; i
= slab_bufctl(slabp
)[i
]) {
2892 if (entries
> cachep
->num
|| i
>= cachep
->num
)
2895 if (entries
!= cachep
->num
- slabp
->inuse
) {
2897 printk(KERN_ERR
"slab: Internal list corruption detected in "
2898 "cache '%s'(%d), slabp %p(%d). Tainted(%s). Hexdump:\n",
2899 cachep
->name
, cachep
->num
, slabp
, slabp
->inuse
,
2901 print_hex_dump(KERN_ERR
, "", DUMP_PREFIX_OFFSET
, 16, 1, slabp
,
2902 sizeof(*slabp
) + cachep
->num
* sizeof(kmem_bufctl_t
),
2908 #define kfree_debugcheck(x) do { } while(0)
2909 #define cache_free_debugcheck(x,objp,z) (objp)
2910 #define check_slabp(x,y) do { } while(0)
2913 static void *cache_alloc_refill(struct kmem_cache
*cachep
, gfp_t flags
,
2917 struct kmem_cache_node
*n
;
2918 struct array_cache
*ac
;
2922 node
= numa_mem_id();
2923 if (unlikely(force_refill
))
2926 ac
= cpu_cache_get(cachep
);
2927 batchcount
= ac
->batchcount
;
2928 if (!ac
->touched
&& batchcount
> BATCHREFILL_LIMIT
) {
2930 * If there was little recent activity on this cache, then
2931 * perform only a partial refill. Otherwise we could generate
2934 batchcount
= BATCHREFILL_LIMIT
;
2936 n
= cachep
->node
[node
];
2938 BUG_ON(ac
->avail
> 0 || !n
);
2939 spin_lock(&n
->list_lock
);
2941 /* See if we can refill from the shared array */
2942 if (n
->shared
&& transfer_objects(ac
, n
->shared
, batchcount
)) {
2943 n
->shared
->touched
= 1;
2947 while (batchcount
> 0) {
2948 struct list_head
*entry
;
2950 /* Get slab alloc is to come from. */
2951 entry
= n
->slabs_partial
.next
;
2952 if (entry
== &n
->slabs_partial
) {
2953 n
->free_touched
= 1;
2954 entry
= n
->slabs_free
.next
;
2955 if (entry
== &n
->slabs_free
)
2959 slabp
= list_entry(entry
, struct slab
, list
);
2960 check_slabp(cachep
, slabp
);
2961 check_spinlock_acquired(cachep
);
2964 * The slab was either on partial or free list so
2965 * there must be at least one object available for
2968 BUG_ON(slabp
->inuse
>= cachep
->num
);
2970 while (slabp
->inuse
< cachep
->num
&& batchcount
--) {
2971 STATS_INC_ALLOCED(cachep
);
2972 STATS_INC_ACTIVE(cachep
);
2973 STATS_SET_HIGH(cachep
);
2975 ac_put_obj(cachep
, ac
, slab_get_obj(cachep
, slabp
,
2978 check_slabp(cachep
, slabp
);
2980 /* move slabp to correct slabp list: */
2981 list_del(&slabp
->list
);
2982 if (slabp
->free
== BUFCTL_END
)
2983 list_add(&slabp
->list
, &n
->slabs_full
);
2985 list_add(&slabp
->list
, &n
->slabs_partial
);
2989 n
->free_objects
-= ac
->avail
;
2991 spin_unlock(&n
->list_lock
);
2993 if (unlikely(!ac
->avail
)) {
2996 x
= cache_grow(cachep
, flags
| GFP_THISNODE
, node
, NULL
);
2998 /* cache_grow can reenable interrupts, then ac could change. */
2999 ac
= cpu_cache_get(cachep
);
3000 node
= numa_mem_id();
3002 /* no objects in sight? abort */
3003 if (!x
&& (ac
->avail
== 0 || force_refill
))
3006 if (!ac
->avail
) /* objects refilled by interrupt? */
3011 return ac_get_obj(cachep
, ac
, flags
, force_refill
);
3014 static inline void cache_alloc_debugcheck_before(struct kmem_cache
*cachep
,
3017 might_sleep_if(flags
& __GFP_WAIT
);
3019 kmem_flagcheck(cachep
, flags
);
3024 static void *cache_alloc_debugcheck_after(struct kmem_cache
*cachep
,
3025 gfp_t flags
, void *objp
, unsigned long caller
)
3029 if (cachep
->flags
& SLAB_POISON
) {
3030 #ifdef CONFIG_DEBUG_PAGEALLOC
3031 if ((cachep
->size
% PAGE_SIZE
) == 0 && OFF_SLAB(cachep
))
3032 kernel_map_pages(virt_to_page(objp
),
3033 cachep
->size
/ PAGE_SIZE
, 1);
3035 check_poison_obj(cachep
, objp
);
3037 check_poison_obj(cachep
, objp
);
3039 poison_obj(cachep
, objp
, POISON_INUSE
);
3041 if (cachep
->flags
& SLAB_STORE_USER
)
3042 *dbg_userword(cachep
, objp
) = (void *)caller
;
3044 if (cachep
->flags
& SLAB_RED_ZONE
) {
3045 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
||
3046 *dbg_redzone2(cachep
, objp
) != RED_INACTIVE
) {
3047 slab_error(cachep
, "double free, or memory outside"
3048 " object was overwritten");
3050 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3051 objp
, *dbg_redzone1(cachep
, objp
),
3052 *dbg_redzone2(cachep
, objp
));
3054 *dbg_redzone1(cachep
, objp
) = RED_ACTIVE
;
3055 *dbg_redzone2(cachep
, objp
) = RED_ACTIVE
;
3057 #ifdef CONFIG_DEBUG_SLAB_LEAK
3062 slabp
= virt_to_slab(objp
);
3063 objnr
= (unsigned)(objp
- slabp
->s_mem
) / cachep
->size
;
3064 slab_bufctl(slabp
)[objnr
] = BUFCTL_ACTIVE
;
3067 objp
+= obj_offset(cachep
);
3068 if (cachep
->ctor
&& cachep
->flags
& SLAB_POISON
)
3070 if (ARCH_SLAB_MINALIGN
&&
3071 ((unsigned long)objp
& (ARCH_SLAB_MINALIGN
-1))) {
3072 printk(KERN_ERR
"0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3073 objp
, (int)ARCH_SLAB_MINALIGN
);
3078 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3081 static bool slab_should_failslab(struct kmem_cache
*cachep
, gfp_t flags
)
3083 if (cachep
== kmem_cache
)
3086 return should_failslab(cachep
->object_size
, flags
, cachep
->flags
);
3089 static inline void *____cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3092 struct array_cache
*ac
;
3093 bool force_refill
= false;
3097 ac
= cpu_cache_get(cachep
);
3098 if (likely(ac
->avail
)) {
3100 objp
= ac_get_obj(cachep
, ac
, flags
, false);
3103 * Allow for the possibility all avail objects are not allowed
3104 * by the current flags
3107 STATS_INC_ALLOCHIT(cachep
);
3110 force_refill
= true;
3113 STATS_INC_ALLOCMISS(cachep
);
3114 objp
= cache_alloc_refill(cachep
, flags
, force_refill
);
3116 * the 'ac' may be updated by cache_alloc_refill(),
3117 * and kmemleak_erase() requires its correct value.
3119 ac
= cpu_cache_get(cachep
);
3123 * To avoid a false negative, if an object that is in one of the
3124 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3125 * treat the array pointers as a reference to the object.
3128 kmemleak_erase(&ac
->entry
[ac
->avail
]);
3134 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3136 * If we are in_interrupt, then process context, including cpusets and
3137 * mempolicy, may not apply and should not be used for allocation policy.
3139 static void *alternate_node_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3141 int nid_alloc
, nid_here
;
3143 if (in_interrupt() || (flags
& __GFP_THISNODE
))
3145 nid_alloc
= nid_here
= numa_mem_id();
3146 if (cpuset_do_slab_mem_spread() && (cachep
->flags
& SLAB_MEM_SPREAD
))
3147 nid_alloc
= cpuset_slab_spread_node();
3148 else if (current
->mempolicy
)
3149 nid_alloc
= slab_node();
3150 if (nid_alloc
!= nid_here
)
3151 return ____cache_alloc_node(cachep
, flags
, nid_alloc
);
3156 * Fallback function if there was no memory available and no objects on a
3157 * certain node and fall back is permitted. First we scan all the
3158 * available node for available objects. If that fails then we
3159 * perform an allocation without specifying a node. This allows the page
3160 * allocator to do its reclaim / fallback magic. We then insert the
3161 * slab into the proper nodelist and then allocate from it.
3163 static void *fallback_alloc(struct kmem_cache
*cache
, gfp_t flags
)
3165 struct zonelist
*zonelist
;
3169 enum zone_type high_zoneidx
= gfp_zone(flags
);
3172 unsigned int cpuset_mems_cookie
;
3174 if (flags
& __GFP_THISNODE
)
3177 local_flags
= flags
& (GFP_CONSTRAINT_MASK
|GFP_RECLAIM_MASK
);
3180 cpuset_mems_cookie
= get_mems_allowed();
3181 zonelist
= node_zonelist(slab_node(), flags
);
3185 * Look through allowed nodes for objects available
3186 * from existing per node queues.
3188 for_each_zone_zonelist(zone
, z
, zonelist
, high_zoneidx
) {
3189 nid
= zone_to_nid(zone
);
3191 if (cpuset_zone_allowed_hardwall(zone
, flags
) &&
3193 cache
->node
[nid
]->free_objects
) {
3194 obj
= ____cache_alloc_node(cache
,
3195 flags
| GFP_THISNODE
, nid
);
3203 * This allocation will be performed within the constraints
3204 * of the current cpuset / memory policy requirements.
3205 * We may trigger various forms of reclaim on the allowed
3206 * set and go into memory reserves if necessary.
3210 if (local_flags
& __GFP_WAIT
)
3212 kmem_flagcheck(cache
, flags
);
3213 page
= kmem_getpages(cache
, local_flags
, numa_mem_id());
3214 if (local_flags
& __GFP_WAIT
)
3215 local_irq_disable();
3218 * Insert into the appropriate per node queues
3220 nid
= page_to_nid(page
);
3221 if (cache_grow(cache
, flags
, nid
, page
)) {
3222 obj
= ____cache_alloc_node(cache
,
3223 flags
| GFP_THISNODE
, nid
);
3226 * Another processor may allocate the
3227 * objects in the slab since we are
3228 * not holding any locks.
3232 /* cache_grow already freed obj */
3238 if (unlikely(!put_mems_allowed(cpuset_mems_cookie
) && !obj
))
3244 * A interface to enable slab creation on nodeid
3246 static void *____cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
,
3249 struct list_head
*entry
;
3251 struct kmem_cache_node
*n
;
3255 VM_BUG_ON(nodeid
> num_online_nodes());
3256 n
= cachep
->node
[nodeid
];
3261 spin_lock(&n
->list_lock
);
3262 entry
= n
->slabs_partial
.next
;
3263 if (entry
== &n
->slabs_partial
) {
3264 n
->free_touched
= 1;
3265 entry
= n
->slabs_free
.next
;
3266 if (entry
== &n
->slabs_free
)
3270 slabp
= list_entry(entry
, struct slab
, list
);
3271 check_spinlock_acquired_node(cachep
, nodeid
);
3272 check_slabp(cachep
, slabp
);
3274 STATS_INC_NODEALLOCS(cachep
);
3275 STATS_INC_ACTIVE(cachep
);
3276 STATS_SET_HIGH(cachep
);
3278 BUG_ON(slabp
->inuse
== cachep
->num
);
3280 obj
= slab_get_obj(cachep
, slabp
, nodeid
);
3281 check_slabp(cachep
, slabp
);
3283 /* move slabp to correct slabp list: */
3284 list_del(&slabp
->list
);
3286 if (slabp
->free
== BUFCTL_END
)
3287 list_add(&slabp
->list
, &n
->slabs_full
);
3289 list_add(&slabp
->list
, &n
->slabs_partial
);
3291 spin_unlock(&n
->list_lock
);
3295 spin_unlock(&n
->list_lock
);
3296 x
= cache_grow(cachep
, flags
| GFP_THISNODE
, nodeid
, NULL
);
3300 return fallback_alloc(cachep
, flags
);
3306 static __always_inline
void *
3307 slab_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
,
3308 unsigned long caller
)
3310 unsigned long save_flags
;
3312 int slab_node
= numa_mem_id();
3314 flags
&= gfp_allowed_mask
;
3316 lockdep_trace_alloc(flags
);
3318 if (slab_should_failslab(cachep
, flags
))
3321 cachep
= memcg_kmem_get_cache(cachep
, flags
);
3323 cache_alloc_debugcheck_before(cachep
, flags
);
3324 local_irq_save(save_flags
);
3326 if (nodeid
== NUMA_NO_NODE
)
3329 if (unlikely(!cachep
->node
[nodeid
])) {
3330 /* Node not bootstrapped yet */
3331 ptr
= fallback_alloc(cachep
, flags
);
3335 if (nodeid
== slab_node
) {
3337 * Use the locally cached objects if possible.
3338 * However ____cache_alloc does not allow fallback
3339 * to other nodes. It may fail while we still have
3340 * objects on other nodes available.
3342 ptr
= ____cache_alloc(cachep
, flags
);
3346 /* ___cache_alloc_node can fall back to other nodes */
3347 ptr
= ____cache_alloc_node(cachep
, flags
, nodeid
);
3349 local_irq_restore(save_flags
);
3350 ptr
= cache_alloc_debugcheck_after(cachep
, flags
, ptr
, caller
);
3351 kmemleak_alloc_recursive(ptr
, cachep
->object_size
, 1, cachep
->flags
,
3355 kmemcheck_slab_alloc(cachep
, flags
, ptr
, cachep
->object_size
);
3357 if (unlikely((flags
& __GFP_ZERO
) && ptr
))
3358 memset(ptr
, 0, cachep
->object_size
);
3363 static __always_inline
void *
3364 __do_cache_alloc(struct kmem_cache
*cache
, gfp_t flags
)
3368 if (unlikely(current
->flags
& (PF_SPREAD_SLAB
| PF_MEMPOLICY
))) {
3369 objp
= alternate_node_alloc(cache
, flags
);
3373 objp
= ____cache_alloc(cache
, flags
);
3376 * We may just have run out of memory on the local node.
3377 * ____cache_alloc_node() knows how to locate memory on other nodes
3380 objp
= ____cache_alloc_node(cache
, flags
, numa_mem_id());
3387 static __always_inline
void *
3388 __do_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3390 return ____cache_alloc(cachep
, flags
);
3393 #endif /* CONFIG_NUMA */
3395 static __always_inline
void *
3396 slab_alloc(struct kmem_cache
*cachep
, gfp_t flags
, unsigned long caller
)
3398 unsigned long save_flags
;
3401 flags
&= gfp_allowed_mask
;
3403 lockdep_trace_alloc(flags
);
3405 if (slab_should_failslab(cachep
, flags
))
3408 cachep
= memcg_kmem_get_cache(cachep
, flags
);
3410 cache_alloc_debugcheck_before(cachep
, flags
);
3411 local_irq_save(save_flags
);
3412 objp
= __do_cache_alloc(cachep
, flags
);
3413 local_irq_restore(save_flags
);
3414 objp
= cache_alloc_debugcheck_after(cachep
, flags
, objp
, caller
);
3415 kmemleak_alloc_recursive(objp
, cachep
->object_size
, 1, cachep
->flags
,
3420 kmemcheck_slab_alloc(cachep
, flags
, objp
, cachep
->object_size
);
3422 if (unlikely((flags
& __GFP_ZERO
) && objp
))
3423 memset(objp
, 0, cachep
->object_size
);
3429 * Caller needs to acquire correct kmem_list's list_lock
3431 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int nr_objects
,
3435 struct kmem_cache_node
*n
;
3437 for (i
= 0; i
< nr_objects
; i
++) {
3441 clear_obj_pfmemalloc(&objpp
[i
]);
3444 slabp
= virt_to_slab(objp
);
3445 n
= cachep
->node
[node
];
3446 list_del(&slabp
->list
);
3447 check_spinlock_acquired_node(cachep
, node
);
3448 check_slabp(cachep
, slabp
);
3449 slab_put_obj(cachep
, slabp
, objp
, node
);
3450 STATS_DEC_ACTIVE(cachep
);
3452 check_slabp(cachep
, slabp
);
3454 /* fixup slab chains */
3455 if (slabp
->inuse
== 0) {
3456 if (n
->free_objects
> n
->free_limit
) {
3457 n
->free_objects
-= cachep
->num
;
3458 /* No need to drop any previously held
3459 * lock here, even if we have a off-slab slab
3460 * descriptor it is guaranteed to come from
3461 * a different cache, refer to comments before
3464 slab_destroy(cachep
, slabp
);
3466 list_add(&slabp
->list
, &n
->slabs_free
);
3469 /* Unconditionally move a slab to the end of the
3470 * partial list on free - maximum time for the
3471 * other objects to be freed, too.
3473 list_add_tail(&slabp
->list
, &n
->slabs_partial
);
3478 static void cache_flusharray(struct kmem_cache
*cachep
, struct array_cache
*ac
)
3481 struct kmem_cache_node
*n
;
3482 int node
= numa_mem_id();
3484 batchcount
= ac
->batchcount
;
3486 BUG_ON(!batchcount
|| batchcount
> ac
->avail
);
3489 n
= cachep
->node
[node
];
3490 spin_lock(&n
->list_lock
);
3492 struct array_cache
*shared_array
= n
->shared
;
3493 int max
= shared_array
->limit
- shared_array
->avail
;
3495 if (batchcount
> max
)
3497 memcpy(&(shared_array
->entry
[shared_array
->avail
]),
3498 ac
->entry
, sizeof(void *) * batchcount
);
3499 shared_array
->avail
+= batchcount
;
3504 free_block(cachep
, ac
->entry
, batchcount
, node
);
3509 struct list_head
*p
;
3511 p
= n
->slabs_free
.next
;
3512 while (p
!= &(n
->slabs_free
)) {
3515 slabp
= list_entry(p
, struct slab
, list
);
3516 BUG_ON(slabp
->inuse
);
3521 STATS_SET_FREEABLE(cachep
, i
);
3524 spin_unlock(&n
->list_lock
);
3525 ac
->avail
-= batchcount
;
3526 memmove(ac
->entry
, &(ac
->entry
[batchcount
]), sizeof(void *)*ac
->avail
);
3530 * Release an obj back to its cache. If the obj has a constructed state, it must
3531 * be in this state _before_ it is released. Called with disabled ints.
3533 static inline void __cache_free(struct kmem_cache
*cachep
, void *objp
,
3534 unsigned long caller
)
3536 struct array_cache
*ac
= cpu_cache_get(cachep
);
3539 kmemleak_free_recursive(objp
, cachep
->flags
);
3540 objp
= cache_free_debugcheck(cachep
, objp
, caller
);
3542 kmemcheck_slab_free(cachep
, objp
, cachep
->object_size
);
3545 * Skip calling cache_free_alien() when the platform is not numa.
3546 * This will avoid cache misses that happen while accessing slabp (which
3547 * is per page memory reference) to get nodeid. Instead use a global
3548 * variable to skip the call, which is mostly likely to be present in
3551 if (nr_online_nodes
> 1 && cache_free_alien(cachep
, objp
))
3554 if (likely(ac
->avail
< ac
->limit
)) {
3555 STATS_INC_FREEHIT(cachep
);
3557 STATS_INC_FREEMISS(cachep
);
3558 cache_flusharray(cachep
, ac
);
3561 ac_put_obj(cachep
, ac
, objp
);
3565 * kmem_cache_alloc - Allocate an object
3566 * @cachep: The cache to allocate from.
3567 * @flags: See kmalloc().
3569 * Allocate an object from this cache. The flags are only relevant
3570 * if the cache has no available objects.
3572 void *kmem_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3574 void *ret
= slab_alloc(cachep
, flags
, _RET_IP_
);
3576 trace_kmem_cache_alloc(_RET_IP_
, ret
,
3577 cachep
->object_size
, cachep
->size
, flags
);
3581 EXPORT_SYMBOL(kmem_cache_alloc
);
3583 #ifdef CONFIG_TRACING
3585 kmem_cache_alloc_trace(struct kmem_cache
*cachep
, gfp_t flags
, size_t size
)
3589 ret
= slab_alloc(cachep
, flags
, _RET_IP_
);
3591 trace_kmalloc(_RET_IP_
, ret
,
3592 size
, cachep
->size
, flags
);
3595 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
3600 * kmem_cache_alloc_node - Allocate an object on the specified node
3601 * @cachep: The cache to allocate from.
3602 * @flags: See kmalloc().
3603 * @nodeid: node number of the target node.
3605 * Identical to kmem_cache_alloc but it will allocate memory on the given
3606 * node, which can improve the performance for cpu bound structures.
3608 * Fallback to other node is possible if __GFP_THISNODE is not set.
3610 void *kmem_cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
3612 void *ret
= slab_alloc_node(cachep
, flags
, nodeid
, _RET_IP_
);
3614 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
3615 cachep
->object_size
, cachep
->size
,
3620 EXPORT_SYMBOL(kmem_cache_alloc_node
);
3622 #ifdef CONFIG_TRACING
3623 void *kmem_cache_alloc_node_trace(struct kmem_cache
*cachep
,
3630 ret
= slab_alloc_node(cachep
, flags
, nodeid
, _RET_IP_
);
3632 trace_kmalloc_node(_RET_IP_
, ret
,
3637 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
3640 static __always_inline
void *
3641 __do_kmalloc_node(size_t size
, gfp_t flags
, int node
, unsigned long caller
)
3643 struct kmem_cache
*cachep
;
3645 cachep
= kmalloc_slab(size
, flags
);
3646 if (unlikely(ZERO_OR_NULL_PTR(cachep
)))
3648 return kmem_cache_alloc_node_trace(cachep
, flags
, node
, size
);
3651 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3652 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3654 return __do_kmalloc_node(size
, flags
, node
, _RET_IP_
);
3656 EXPORT_SYMBOL(__kmalloc_node
);
3658 void *__kmalloc_node_track_caller(size_t size
, gfp_t flags
,
3659 int node
, unsigned long caller
)
3661 return __do_kmalloc_node(size
, flags
, node
, caller
);
3663 EXPORT_SYMBOL(__kmalloc_node_track_caller
);
3665 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3667 return __do_kmalloc_node(size
, flags
, node
, 0);
3669 EXPORT_SYMBOL(__kmalloc_node
);
3670 #endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */
3671 #endif /* CONFIG_NUMA */
3674 * __do_kmalloc - allocate memory
3675 * @size: how many bytes of memory are required.
3676 * @flags: the type of memory to allocate (see kmalloc).
3677 * @caller: function caller for debug tracking of the caller
3679 static __always_inline
void *__do_kmalloc(size_t size
, gfp_t flags
,
3680 unsigned long caller
)
3682 struct kmem_cache
*cachep
;
3685 /* If you want to save a few bytes .text space: replace
3687 * Then kmalloc uses the uninlined functions instead of the inline
3690 cachep
= kmalloc_slab(size
, flags
);
3691 if (unlikely(ZERO_OR_NULL_PTR(cachep
)))
3693 ret
= slab_alloc(cachep
, flags
, caller
);
3695 trace_kmalloc(caller
, ret
,
3696 size
, cachep
->size
, flags
);
3702 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
3703 void *__kmalloc(size_t size
, gfp_t flags
)
3705 return __do_kmalloc(size
, flags
, _RET_IP_
);
3707 EXPORT_SYMBOL(__kmalloc
);
3709 void *__kmalloc_track_caller(size_t size
, gfp_t flags
, unsigned long caller
)
3711 return __do_kmalloc(size
, flags
, caller
);
3713 EXPORT_SYMBOL(__kmalloc_track_caller
);
3716 void *__kmalloc(size_t size
, gfp_t flags
)
3718 return __do_kmalloc(size
, flags
, 0);
3720 EXPORT_SYMBOL(__kmalloc
);
3724 * kmem_cache_free - Deallocate an object
3725 * @cachep: The cache the allocation was from.
3726 * @objp: The previously allocated object.
3728 * Free an object which was previously allocated from this
3731 void kmem_cache_free(struct kmem_cache
*cachep
, void *objp
)
3733 unsigned long flags
;
3734 cachep
= cache_from_obj(cachep
, objp
);
3738 local_irq_save(flags
);
3739 debug_check_no_locks_freed(objp
, cachep
->object_size
);
3740 if (!(cachep
->flags
& SLAB_DEBUG_OBJECTS
))
3741 debug_check_no_obj_freed(objp
, cachep
->object_size
);
3742 __cache_free(cachep
, objp
, _RET_IP_
);
3743 local_irq_restore(flags
);
3745 trace_kmem_cache_free(_RET_IP_
, objp
);
3747 EXPORT_SYMBOL(kmem_cache_free
);
3750 * kfree - free previously allocated memory
3751 * @objp: pointer returned by kmalloc.
3753 * If @objp is NULL, no operation is performed.
3755 * Don't free memory not originally allocated by kmalloc()
3756 * or you will run into trouble.
3758 void kfree(const void *objp
)
3760 struct kmem_cache
*c
;
3761 unsigned long flags
;
3763 trace_kfree(_RET_IP_
, objp
);
3765 if (unlikely(ZERO_OR_NULL_PTR(objp
)))
3767 local_irq_save(flags
);
3768 kfree_debugcheck(objp
);
3769 c
= virt_to_cache(objp
);
3770 debug_check_no_locks_freed(objp
, c
->object_size
);
3772 debug_check_no_obj_freed(objp
, c
->object_size
);
3773 __cache_free(c
, (void *)objp
, _RET_IP_
);
3774 local_irq_restore(flags
);
3776 EXPORT_SYMBOL(kfree
);
3779 * This initializes kmem_cache_node or resizes various caches for all nodes.
3781 static int alloc_kmemlist(struct kmem_cache
*cachep
, gfp_t gfp
)
3784 struct kmem_cache_node
*n
;
3785 struct array_cache
*new_shared
;
3786 struct array_cache
**new_alien
= NULL
;
3788 for_each_online_node(node
) {
3790 if (use_alien_caches
) {
3791 new_alien
= alloc_alien_cache(node
, cachep
->limit
, gfp
);
3797 if (cachep
->shared
) {
3798 new_shared
= alloc_arraycache(node
,
3799 cachep
->shared
*cachep
->batchcount
,
3802 free_alien_cache(new_alien
);
3807 n
= cachep
->node
[node
];
3809 struct array_cache
*shared
= n
->shared
;
3811 spin_lock_irq(&n
->list_lock
);
3814 free_block(cachep
, shared
->entry
,
3815 shared
->avail
, node
);
3817 n
->shared
= new_shared
;
3819 n
->alien
= new_alien
;
3822 n
->free_limit
= (1 + nr_cpus_node(node
)) *
3823 cachep
->batchcount
+ cachep
->num
;
3824 spin_unlock_irq(&n
->list_lock
);
3826 free_alien_cache(new_alien
);
3829 n
= kmalloc_node(sizeof(struct kmem_cache_node
), gfp
, node
);
3831 free_alien_cache(new_alien
);
3836 kmem_cache_node_init(n
);
3837 n
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
+
3838 ((unsigned long)cachep
) % REAPTIMEOUT_LIST3
;
3839 n
->shared
= new_shared
;
3840 n
->alien
= new_alien
;
3841 n
->free_limit
= (1 + nr_cpus_node(node
)) *
3842 cachep
->batchcount
+ cachep
->num
;
3843 cachep
->node
[node
] = n
;
3848 if (!cachep
->list
.next
) {
3849 /* Cache is not active yet. Roll back what we did */
3852 if (cachep
->node
[node
]) {
3853 n
= cachep
->node
[node
];
3856 free_alien_cache(n
->alien
);
3858 cachep
->node
[node
] = NULL
;
3866 struct ccupdate_struct
{
3867 struct kmem_cache
*cachep
;
3868 struct array_cache
*new[0];
3871 static void do_ccupdate_local(void *info
)
3873 struct ccupdate_struct
*new = info
;
3874 struct array_cache
*old
;
3877 old
= cpu_cache_get(new->cachep
);
3879 new->cachep
->array
[smp_processor_id()] = new->new[smp_processor_id()];
3880 new->new[smp_processor_id()] = old
;
3883 /* Always called with the slab_mutex held */
3884 static int __do_tune_cpucache(struct kmem_cache
*cachep
, int limit
,
3885 int batchcount
, int shared
, gfp_t gfp
)
3887 struct ccupdate_struct
*new;
3890 new = kzalloc(sizeof(*new) + nr_cpu_ids
* sizeof(struct array_cache
*),
3895 for_each_online_cpu(i
) {
3896 new->new[i
] = alloc_arraycache(cpu_to_mem(i
), limit
,
3899 for (i
--; i
>= 0; i
--)
3905 new->cachep
= cachep
;
3907 on_each_cpu(do_ccupdate_local
, (void *)new, 1);
3910 cachep
->batchcount
= batchcount
;
3911 cachep
->limit
= limit
;
3912 cachep
->shared
= shared
;
3914 for_each_online_cpu(i
) {
3915 struct array_cache
*ccold
= new->new[i
];
3918 spin_lock_irq(&cachep
->node
[cpu_to_mem(i
)]->list_lock
);
3919 free_block(cachep
, ccold
->entry
, ccold
->avail
, cpu_to_mem(i
));
3920 spin_unlock_irq(&cachep
->node
[cpu_to_mem(i
)]->list_lock
);
3924 return alloc_kmemlist(cachep
, gfp
);
3927 static int do_tune_cpucache(struct kmem_cache
*cachep
, int limit
,
3928 int batchcount
, int shared
, gfp_t gfp
)
3931 struct kmem_cache
*c
= NULL
;
3934 ret
= __do_tune_cpucache(cachep
, limit
, batchcount
, shared
, gfp
);
3936 if (slab_state
< FULL
)
3939 if ((ret
< 0) || !is_root_cache(cachep
))
3942 VM_BUG_ON(!mutex_is_locked(&slab_mutex
));
3943 for_each_memcg_cache_index(i
) {
3944 c
= cache_from_memcg(cachep
, i
);
3946 /* return value determined by the parent cache only */
3947 __do_tune_cpucache(c
, limit
, batchcount
, shared
, gfp
);
3953 /* Called with slab_mutex held always */
3954 static int enable_cpucache(struct kmem_cache
*cachep
, gfp_t gfp
)
3961 if (!is_root_cache(cachep
)) {
3962 struct kmem_cache
*root
= memcg_root_cache(cachep
);
3963 limit
= root
->limit
;
3964 shared
= root
->shared
;
3965 batchcount
= root
->batchcount
;
3968 if (limit
&& shared
&& batchcount
)
3971 * The head array serves three purposes:
3972 * - create a LIFO ordering, i.e. return objects that are cache-warm
3973 * - reduce the number of spinlock operations.
3974 * - reduce the number of linked list operations on the slab and
3975 * bufctl chains: array operations are cheaper.
3976 * The numbers are guessed, we should auto-tune as described by
3979 if (cachep
->size
> 131072)
3981 else if (cachep
->size
> PAGE_SIZE
)
3983 else if (cachep
->size
> 1024)
3985 else if (cachep
->size
> 256)
3991 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3992 * allocation behaviour: Most allocs on one cpu, most free operations
3993 * on another cpu. For these cases, an efficient object passing between
3994 * cpus is necessary. This is provided by a shared array. The array
3995 * replaces Bonwick's magazine layer.
3996 * On uniprocessor, it's functionally equivalent (but less efficient)
3997 * to a larger limit. Thus disabled by default.
4000 if (cachep
->size
<= PAGE_SIZE
&& num_possible_cpus() > 1)
4005 * With debugging enabled, large batchcount lead to excessively long
4006 * periods with disabled local interrupts. Limit the batchcount
4011 batchcount
= (limit
+ 1) / 2;
4013 err
= do_tune_cpucache(cachep
, limit
, batchcount
, shared
, gfp
);
4015 printk(KERN_ERR
"enable_cpucache failed for %s, error %d.\n",
4016 cachep
->name
, -err
);
4021 * Drain an array if it contains any elements taking the node lock only if
4022 * necessary. Note that the node listlock also protects the array_cache
4023 * if drain_array() is used on the shared array.
4025 static void drain_array(struct kmem_cache
*cachep
, struct kmem_cache_node
*n
,
4026 struct array_cache
*ac
, int force
, int node
)
4030 if (!ac
|| !ac
->avail
)
4032 if (ac
->touched
&& !force
) {
4035 spin_lock_irq(&n
->list_lock
);
4037 tofree
= force
? ac
->avail
: (ac
->limit
+ 4) / 5;
4038 if (tofree
> ac
->avail
)
4039 tofree
= (ac
->avail
+ 1) / 2;
4040 free_block(cachep
, ac
->entry
, tofree
, node
);
4041 ac
->avail
-= tofree
;
4042 memmove(ac
->entry
, &(ac
->entry
[tofree
]),
4043 sizeof(void *) * ac
->avail
);
4045 spin_unlock_irq(&n
->list_lock
);
4050 * cache_reap - Reclaim memory from caches.
4051 * @w: work descriptor
4053 * Called from workqueue/eventd every few seconds.
4055 * - clear the per-cpu caches for this CPU.
4056 * - return freeable pages to the main free memory pool.
4058 * If we cannot acquire the cache chain mutex then just give up - we'll try
4059 * again on the next iteration.
4061 static void cache_reap(struct work_struct
*w
)
4063 struct kmem_cache
*searchp
;
4064 struct kmem_cache_node
*n
;
4065 int node
= numa_mem_id();
4066 struct delayed_work
*work
= to_delayed_work(w
);
4068 if (!mutex_trylock(&slab_mutex
))
4069 /* Give up. Setup the next iteration. */
4072 list_for_each_entry(searchp
, &slab_caches
, list
) {
4076 * We only take the node lock if absolutely necessary and we
4077 * have established with reasonable certainty that
4078 * we can do some work if the lock was obtained.
4080 n
= searchp
->node
[node
];
4082 reap_alien(searchp
, n
);
4084 drain_array(searchp
, n
, cpu_cache_get(searchp
), 0, node
);
4087 * These are racy checks but it does not matter
4088 * if we skip one check or scan twice.
4090 if (time_after(n
->next_reap
, jiffies
))
4093 n
->next_reap
= jiffies
+ REAPTIMEOUT_LIST3
;
4095 drain_array(searchp
, n
, n
->shared
, 0, node
);
4097 if (n
->free_touched
)
4098 n
->free_touched
= 0;
4102 freed
= drain_freelist(searchp
, n
, (n
->free_limit
+
4103 5 * searchp
->num
- 1) / (5 * searchp
->num
));
4104 STATS_ADD_REAPED(searchp
, freed
);
4110 mutex_unlock(&slab_mutex
);
4113 /* Set up the next iteration */
4114 schedule_delayed_work(work
, round_jiffies_relative(REAPTIMEOUT_CPUC
));
4117 #ifdef CONFIG_SLABINFO
4118 void get_slabinfo(struct kmem_cache
*cachep
, struct slabinfo
*sinfo
)
4121 unsigned long active_objs
;
4122 unsigned long num_objs
;
4123 unsigned long active_slabs
= 0;
4124 unsigned long num_slabs
, free_objects
= 0, shared_avail
= 0;
4128 struct kmem_cache_node
*n
;
4132 for_each_online_node(node
) {
4133 n
= cachep
->node
[node
];
4138 spin_lock_irq(&n
->list_lock
);
4140 list_for_each_entry(slabp
, &n
->slabs_full
, list
) {
4141 if (slabp
->inuse
!= cachep
->num
&& !error
)
4142 error
= "slabs_full accounting error";
4143 active_objs
+= cachep
->num
;
4146 list_for_each_entry(slabp
, &n
->slabs_partial
, list
) {
4147 if (slabp
->inuse
== cachep
->num
&& !error
)
4148 error
= "slabs_partial inuse accounting error";
4149 if (!slabp
->inuse
&& !error
)
4150 error
= "slabs_partial/inuse accounting error";
4151 active_objs
+= slabp
->inuse
;
4154 list_for_each_entry(slabp
, &n
->slabs_free
, list
) {
4155 if (slabp
->inuse
&& !error
)
4156 error
= "slabs_free/inuse accounting error";
4159 free_objects
+= n
->free_objects
;
4161 shared_avail
+= n
->shared
->avail
;
4163 spin_unlock_irq(&n
->list_lock
);
4165 num_slabs
+= active_slabs
;
4166 num_objs
= num_slabs
* cachep
->num
;
4167 if (num_objs
- active_objs
!= free_objects
&& !error
)
4168 error
= "free_objects accounting error";
4170 name
= cachep
->name
;
4172 printk(KERN_ERR
"slab: cache %s error: %s\n", name
, error
);
4174 sinfo
->active_objs
= active_objs
;
4175 sinfo
->num_objs
= num_objs
;
4176 sinfo
->active_slabs
= active_slabs
;
4177 sinfo
->num_slabs
= num_slabs
;
4178 sinfo
->shared_avail
= shared_avail
;
4179 sinfo
->limit
= cachep
->limit
;
4180 sinfo
->batchcount
= cachep
->batchcount
;
4181 sinfo
->shared
= cachep
->shared
;
4182 sinfo
->objects_per_slab
= cachep
->num
;
4183 sinfo
->cache_order
= cachep
->gfporder
;
4186 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*cachep
)
4190 unsigned long high
= cachep
->high_mark
;
4191 unsigned long allocs
= cachep
->num_allocations
;
4192 unsigned long grown
= cachep
->grown
;
4193 unsigned long reaped
= cachep
->reaped
;
4194 unsigned long errors
= cachep
->errors
;
4195 unsigned long max_freeable
= cachep
->max_freeable
;
4196 unsigned long node_allocs
= cachep
->node_allocs
;
4197 unsigned long node_frees
= cachep
->node_frees
;
4198 unsigned long overflows
= cachep
->node_overflow
;
4200 seq_printf(m
, " : globalstat %7lu %6lu %5lu %4lu "
4201 "%4lu %4lu %4lu %4lu %4lu",
4202 allocs
, high
, grown
,
4203 reaped
, errors
, max_freeable
, node_allocs
,
4204 node_frees
, overflows
);
4208 unsigned long allochit
= atomic_read(&cachep
->allochit
);
4209 unsigned long allocmiss
= atomic_read(&cachep
->allocmiss
);
4210 unsigned long freehit
= atomic_read(&cachep
->freehit
);
4211 unsigned long freemiss
= atomic_read(&cachep
->freemiss
);
4213 seq_printf(m
, " : cpustat %6lu %6lu %6lu %6lu",
4214 allochit
, allocmiss
, freehit
, freemiss
);
4219 #define MAX_SLABINFO_WRITE 128
4221 * slabinfo_write - Tuning for the slab allocator
4223 * @buffer: user buffer
4224 * @count: data length
4227 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
4228 size_t count
, loff_t
*ppos
)
4230 char kbuf
[MAX_SLABINFO_WRITE
+ 1], *tmp
;
4231 int limit
, batchcount
, shared
, res
;
4232 struct kmem_cache
*cachep
;
4234 if (count
> MAX_SLABINFO_WRITE
)
4236 if (copy_from_user(&kbuf
, buffer
, count
))
4238 kbuf
[MAX_SLABINFO_WRITE
] = '\0';
4240 tmp
= strchr(kbuf
, ' ');
4245 if (sscanf(tmp
, " %d %d %d", &limit
, &batchcount
, &shared
) != 3)
4248 /* Find the cache in the chain of caches. */
4249 mutex_lock(&slab_mutex
);
4251 list_for_each_entry(cachep
, &slab_caches
, list
) {
4252 if (!strcmp(cachep
->name
, kbuf
)) {
4253 if (limit
< 1 || batchcount
< 1 ||
4254 batchcount
> limit
|| shared
< 0) {
4257 res
= do_tune_cpucache(cachep
, limit
,
4264 mutex_unlock(&slab_mutex
);
4270 #ifdef CONFIG_DEBUG_SLAB_LEAK
4272 static void *leaks_start(struct seq_file
*m
, loff_t
*pos
)
4274 mutex_lock(&slab_mutex
);
4275 return seq_list_start(&slab_caches
, *pos
);
4278 static inline int add_caller(unsigned long *n
, unsigned long v
)
4288 unsigned long *q
= p
+ 2 * i
;
4302 memmove(p
+ 2, p
, n
[1] * 2 * sizeof(unsigned long) - ((void *)p
- (void *)n
));
4308 static void handle_slab(unsigned long *n
, struct kmem_cache
*c
, struct slab
*s
)
4314 for (i
= 0, p
= s
->s_mem
; i
< c
->num
; i
++, p
+= c
->size
) {
4315 if (slab_bufctl(s
)[i
] != BUFCTL_ACTIVE
)
4317 if (!add_caller(n
, (unsigned long)*dbg_userword(c
, p
)))
4322 static void show_symbol(struct seq_file
*m
, unsigned long address
)
4324 #ifdef CONFIG_KALLSYMS
4325 unsigned long offset
, size
;
4326 char modname
[MODULE_NAME_LEN
], name
[KSYM_NAME_LEN
];
4328 if (lookup_symbol_attrs(address
, &size
, &offset
, modname
, name
) == 0) {
4329 seq_printf(m
, "%s+%#lx/%#lx", name
, offset
, size
);
4331 seq_printf(m
, " [%s]", modname
);
4335 seq_printf(m
, "%p", (void *)address
);
4338 static int leaks_show(struct seq_file
*m
, void *p
)
4340 struct kmem_cache
*cachep
= list_entry(p
, struct kmem_cache
, list
);
4342 struct kmem_cache_node
*n
;
4344 unsigned long *x
= m
->private;
4348 if (!(cachep
->flags
& SLAB_STORE_USER
))
4350 if (!(cachep
->flags
& SLAB_RED_ZONE
))
4353 /* OK, we can do it */
4357 for_each_online_node(node
) {
4358 n
= cachep
->node
[node
];
4363 spin_lock_irq(&n
->list_lock
);
4365 list_for_each_entry(slabp
, &n
->slabs_full
, list
)
4366 handle_slab(x
, cachep
, slabp
);
4367 list_for_each_entry(slabp
, &n
->slabs_partial
, list
)
4368 handle_slab(x
, cachep
, slabp
);
4369 spin_unlock_irq(&n
->list_lock
);
4371 name
= cachep
->name
;
4373 /* Increase the buffer size */
4374 mutex_unlock(&slab_mutex
);
4375 m
->private = kzalloc(x
[0] * 4 * sizeof(unsigned long), GFP_KERNEL
);
4377 /* Too bad, we are really out */
4379 mutex_lock(&slab_mutex
);
4382 *(unsigned long *)m
->private = x
[0] * 2;
4384 mutex_lock(&slab_mutex
);
4385 /* Now make sure this entry will be retried */
4389 for (i
= 0; i
< x
[1]; i
++) {
4390 seq_printf(m
, "%s: %lu ", name
, x
[2*i
+3]);
4391 show_symbol(m
, x
[2*i
+2]);
4398 static const struct seq_operations slabstats_op
= {
4399 .start
= leaks_start
,
4405 static int slabstats_open(struct inode
*inode
, struct file
*file
)
4407 unsigned long *n
= kzalloc(PAGE_SIZE
, GFP_KERNEL
);
4410 ret
= seq_open(file
, &slabstats_op
);
4412 struct seq_file
*m
= file
->private_data
;
4413 *n
= PAGE_SIZE
/ (2 * sizeof(unsigned long));
4422 static const struct file_operations proc_slabstats_operations
= {
4423 .open
= slabstats_open
,
4425 .llseek
= seq_lseek
,
4426 .release
= seq_release_private
,
4430 static int __init
slab_proc_init(void)
4432 #ifdef CONFIG_DEBUG_SLAB_LEAK
4433 proc_create("slab_allocators", 0, NULL
, &proc_slabstats_operations
);
4437 module_init(slab_proc_init
);
4441 * ksize - get the actual amount of memory allocated for a given object
4442 * @objp: Pointer to the object
4444 * kmalloc may internally round up allocations and return more memory
4445 * than requested. ksize() can be used to determine the actual amount of
4446 * memory allocated. The caller may use this additional memory, even though
4447 * a smaller amount of memory was initially specified with the kmalloc call.
4448 * The caller must guarantee that objp points to a valid object previously
4449 * allocated with either kmalloc() or kmem_cache_alloc(). The object
4450 * must not be freed during the duration of the call.
4452 size_t ksize(const void *objp
)
4455 if (unlikely(objp
== ZERO_SIZE_PTR
))
4458 return virt_to_cache(objp
)->object_size
;
4460 EXPORT_SYMBOL(ksize
);