xref: /openbmc/linux/mm/slab.c (revision e8e0929d)
1 /*
2  * linux/mm/slab.c
3  * Written by Mark Hemment, 1996/97.
4  * (markhe@nextd.demon.co.uk)
5  *
6  * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
7  *
8  * Major cleanup, different bufctl logic, per-cpu arrays
9  *	(c) 2000 Manfred Spraul
10  *
11  * Cleanup, make the head arrays unconditional, preparation for NUMA
12  * 	(c) 2002 Manfred Spraul
13  *
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
21  *
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.
27  *
28  * This means, that your constructor is used only for newly allocated
29  * slabs and you must pass objects with the same initializations to
30  * kmem_cache_free.
31  *
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.
35  *
36  * In order to reduce fragmentation, the slabs are sorted in 3 groups:
37  *   full slabs with 0 free objects
38  *   partial slabs
39  *   empty slabs with no allocated objects
40  *
41  * If partial slabs exist, then new allocations come from these slabs,
42  * otherwise from empty slabs or new slabs are allocated.
43  *
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.
46  *
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.
52  *
53  * The c_cpuarray may not be read with enabled local interrupts -
54  * it's changed with a smp_call_function().
55  *
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.
63  *
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
66  * his patch.
67  *
68  * Further notes from the original documentation:
69  *
70  * 11 April '97.  Started multi-threading - markhe
71  *	The global cache-chain is protected by the mutex 'cache_chain_mutex'.
72  *	The sem is only needed when accessing/extending the cache-chain, which
73  *	can never happen inside an interrupt (kmem_cache_create(),
74  *	kmem_cache_shrink() and kmem_cache_reap()).
75  *
76  *	At present, each engine can be growing a cache.  This should be blocked.
77  *
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>
83  *
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.
87  */
88 
89 #include	<linux/slab.h>
90 #include	<linux/mm.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/kmemtrace.h>
106 #include	<linux/rcupdate.h>
107 #include	<linux/string.h>
108 #include	<linux/uaccess.h>
109 #include	<linux/nodemask.h>
110 #include	<linux/kmemleak.h>
111 #include	<linux/mempolicy.h>
112 #include	<linux/mutex.h>
113 #include	<linux/fault-inject.h>
114 #include	<linux/rtmutex.h>
115 #include	<linux/reciprocal_div.h>
116 #include	<linux/debugobjects.h>
117 #include	<linux/kmemcheck.h>
118 
119 #include	<asm/cacheflush.h>
120 #include	<asm/tlbflush.h>
121 #include	<asm/page.h>
122 
123 /*
124  * DEBUG	- 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
125  *		  0 for faster, smaller code (especially in the critical paths).
126  *
127  * STATS	- 1 to collect stats for /proc/slabinfo.
128  *		  0 for faster, smaller code (especially in the critical paths).
129  *
130  * FORCED_DEBUG	- 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
131  */
132 
133 #ifdef CONFIG_DEBUG_SLAB
134 #define	DEBUG		1
135 #define	STATS		1
136 #define	FORCED_DEBUG	1
137 #else
138 #define	DEBUG		0
139 #define	STATS		0
140 #define	FORCED_DEBUG	0
141 #endif
142 
143 /* Shouldn't this be in a header file somewhere? */
144 #define	BYTES_PER_WORD		sizeof(void *)
145 #define	REDZONE_ALIGN		max(BYTES_PER_WORD, __alignof__(unsigned long long))
146 
147 #ifndef ARCH_KMALLOC_MINALIGN
148 /*
149  * Enforce a minimum alignment for the kmalloc caches.
150  * Usually, the kmalloc caches are cache_line_size() aligned, except when
151  * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
152  * Some archs want to perform DMA into kmalloc caches and need a guaranteed
153  * alignment larger than the alignment of a 64-bit integer.
154  * ARCH_KMALLOC_MINALIGN allows that.
155  * Note that increasing this value may disable some debug features.
156  */
157 #define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
158 #endif
159 
160 #ifndef ARCH_SLAB_MINALIGN
161 /*
162  * Enforce a minimum alignment for all caches.
163  * Intended for archs that get misalignment faults even for BYTES_PER_WORD
164  * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
165  * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
166  * some debug features.
167  */
168 #define ARCH_SLAB_MINALIGN 0
169 #endif
170 
171 #ifndef ARCH_KMALLOC_FLAGS
172 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
173 #endif
174 
175 /* Legal flag mask for kmem_cache_create(). */
176 #if DEBUG
177 # define CREATE_MASK	(SLAB_RED_ZONE | \
178 			 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
179 			 SLAB_CACHE_DMA | \
180 			 SLAB_STORE_USER | \
181 			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
182 			 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
183 			 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
184 #else
185 # define CREATE_MASK	(SLAB_HWCACHE_ALIGN | \
186 			 SLAB_CACHE_DMA | \
187 			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
188 			 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
189 			 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
190 #endif
191 
192 /*
193  * kmem_bufctl_t:
194  *
195  * Bufctl's are used for linking objs within a slab
196  * linked offsets.
197  *
198  * This implementation relies on "struct page" for locating the cache &
199  * slab an object belongs to.
200  * This allows the bufctl structure to be small (one int), but limits
201  * the number of objects a slab (not a cache) can contain when off-slab
202  * bufctls are used. The limit is the size of the largest general cache
203  * that does not use off-slab slabs.
204  * For 32bit archs with 4 kB pages, is this 56.
205  * This is not serious, as it is only for large objects, when it is unwise
206  * to have too many per slab.
207  * Note: This limit can be raised by introducing a general cache whose size
208  * is less than 512 (PAGE_SIZE<<3), but greater than 256.
209  */
210 
211 typedef unsigned int kmem_bufctl_t;
212 #define BUFCTL_END	(((kmem_bufctl_t)(~0U))-0)
213 #define BUFCTL_FREE	(((kmem_bufctl_t)(~0U))-1)
214 #define	BUFCTL_ACTIVE	(((kmem_bufctl_t)(~0U))-2)
215 #define	SLAB_LIMIT	(((kmem_bufctl_t)(~0U))-3)
216 
217 /*
218  * struct slab
219  *
220  * Manages the objs in a slab. Placed either at the beginning of mem allocated
221  * for a slab, or allocated from an general cache.
222  * Slabs are chained into three list: fully used, partial, fully free slabs.
223  */
224 struct slab {
225 	struct list_head list;
226 	unsigned long colouroff;
227 	void *s_mem;		/* including colour offset */
228 	unsigned int inuse;	/* num of objs active in slab */
229 	kmem_bufctl_t free;
230 	unsigned short nodeid;
231 };
232 
233 /*
234  * struct slab_rcu
235  *
236  * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
237  * arrange for kmem_freepages to be called via RCU.  This is useful if
238  * we need to approach a kernel structure obliquely, from its address
239  * obtained without the usual locking.  We can lock the structure to
240  * stabilize it and check it's still at the given address, only if we
241  * can be sure that the memory has not been meanwhile reused for some
242  * other kind of object (which our subsystem's lock might corrupt).
243  *
244  * rcu_read_lock before reading the address, then rcu_read_unlock after
245  * taking the spinlock within the structure expected at that address.
246  *
247  * We assume struct slab_rcu can overlay struct slab when destroying.
248  */
249 struct slab_rcu {
250 	struct rcu_head head;
251 	struct kmem_cache *cachep;
252 	void *addr;
253 };
254 
255 /*
256  * struct array_cache
257  *
258  * Purpose:
259  * - LIFO ordering, to hand out cache-warm objects from _alloc
260  * - reduce the number of linked list operations
261  * - reduce spinlock operations
262  *
263  * The limit is stored in the per-cpu structure to reduce the data cache
264  * footprint.
265  *
266  */
267 struct array_cache {
268 	unsigned int avail;
269 	unsigned int limit;
270 	unsigned int batchcount;
271 	unsigned int touched;
272 	spinlock_t lock;
273 	void *entry[];	/*
274 			 * Must have this definition in here for the proper
275 			 * alignment of array_cache. Also simplifies accessing
276 			 * the entries.
277 			 */
278 };
279 
280 /*
281  * bootstrap: The caches do not work without cpuarrays anymore, but the
282  * cpuarrays are allocated from the generic caches...
283  */
284 #define BOOT_CPUCACHE_ENTRIES	1
285 struct arraycache_init {
286 	struct array_cache cache;
287 	void *entries[BOOT_CPUCACHE_ENTRIES];
288 };
289 
290 /*
291  * The slab lists for all objects.
292  */
293 struct kmem_list3 {
294 	struct list_head slabs_partial;	/* partial list first, better asm code */
295 	struct list_head slabs_full;
296 	struct list_head slabs_free;
297 	unsigned long free_objects;
298 	unsigned int free_limit;
299 	unsigned int colour_next;	/* Per-node cache coloring */
300 	spinlock_t list_lock;
301 	struct array_cache *shared;	/* shared per node */
302 	struct array_cache **alien;	/* on other nodes */
303 	unsigned long next_reap;	/* updated without locking */
304 	int free_touched;		/* updated without locking */
305 };
306 
307 /*
308  * Need this for bootstrapping a per node allocator.
309  */
310 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
311 struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
312 #define	CACHE_CACHE 0
313 #define	SIZE_AC MAX_NUMNODES
314 #define	SIZE_L3 (2 * MAX_NUMNODES)
315 
316 static int drain_freelist(struct kmem_cache *cache,
317 			struct kmem_list3 *l3, int tofree);
318 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
319 			int node);
320 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
321 static void cache_reap(struct work_struct *unused);
322 
323 /*
324  * This function must be completely optimized away if a constant is passed to
325  * it.  Mostly the same as what is in linux/slab.h except it returns an index.
326  */
327 static __always_inline int index_of(const size_t size)
328 {
329 	extern void __bad_size(void);
330 
331 	if (__builtin_constant_p(size)) {
332 		int i = 0;
333 
334 #define CACHE(x) \
335 	if (size <=x) \
336 		return i; \
337 	else \
338 		i++;
339 #include <linux/kmalloc_sizes.h>
340 #undef CACHE
341 		__bad_size();
342 	} else
343 		__bad_size();
344 	return 0;
345 }
346 
347 static int slab_early_init = 1;
348 
349 #define INDEX_AC index_of(sizeof(struct arraycache_init))
350 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
351 
352 static void kmem_list3_init(struct kmem_list3 *parent)
353 {
354 	INIT_LIST_HEAD(&parent->slabs_full);
355 	INIT_LIST_HEAD(&parent->slabs_partial);
356 	INIT_LIST_HEAD(&parent->slabs_free);
357 	parent->shared = NULL;
358 	parent->alien = NULL;
359 	parent->colour_next = 0;
360 	spin_lock_init(&parent->list_lock);
361 	parent->free_objects = 0;
362 	parent->free_touched = 0;
363 }
364 
365 #define MAKE_LIST(cachep, listp, slab, nodeid)				\
366 	do {								\
367 		INIT_LIST_HEAD(listp);					\
368 		list_splice(&(cachep->nodelists[nodeid]->slab), listp);	\
369 	} while (0)
370 
371 #define	MAKE_ALL_LISTS(cachep, ptr, nodeid)				\
372 	do {								\
373 	MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid);	\
374 	MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
375 	MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid);	\
376 	} while (0)
377 
378 #define CFLGS_OFF_SLAB		(0x80000000UL)
379 #define	OFF_SLAB(x)	((x)->flags & CFLGS_OFF_SLAB)
380 
381 #define BATCHREFILL_LIMIT	16
382 /*
383  * Optimization question: fewer reaps means less probability for unnessary
384  * cpucache drain/refill cycles.
385  *
386  * OTOH the cpuarrays can contain lots of objects,
387  * which could lock up otherwise freeable slabs.
388  */
389 #define REAPTIMEOUT_CPUC	(2*HZ)
390 #define REAPTIMEOUT_LIST3	(4*HZ)
391 
392 #if STATS
393 #define	STATS_INC_ACTIVE(x)	((x)->num_active++)
394 #define	STATS_DEC_ACTIVE(x)	((x)->num_active--)
395 #define	STATS_INC_ALLOCED(x)	((x)->num_allocations++)
396 #define	STATS_INC_GROWN(x)	((x)->grown++)
397 #define	STATS_ADD_REAPED(x,y)	((x)->reaped += (y))
398 #define	STATS_SET_HIGH(x)						\
399 	do {								\
400 		if ((x)->num_active > (x)->high_mark)			\
401 			(x)->high_mark = (x)->num_active;		\
402 	} while (0)
403 #define	STATS_INC_ERR(x)	((x)->errors++)
404 #define	STATS_INC_NODEALLOCS(x)	((x)->node_allocs++)
405 #define	STATS_INC_NODEFREES(x)	((x)->node_frees++)
406 #define STATS_INC_ACOVERFLOW(x)   ((x)->node_overflow++)
407 #define	STATS_SET_FREEABLE(x, i)					\
408 	do {								\
409 		if ((x)->max_freeable < i)				\
410 			(x)->max_freeable = i;				\
411 	} while (0)
412 #define STATS_INC_ALLOCHIT(x)	atomic_inc(&(x)->allochit)
413 #define STATS_INC_ALLOCMISS(x)	atomic_inc(&(x)->allocmiss)
414 #define STATS_INC_FREEHIT(x)	atomic_inc(&(x)->freehit)
415 #define STATS_INC_FREEMISS(x)	atomic_inc(&(x)->freemiss)
416 #else
417 #define	STATS_INC_ACTIVE(x)	do { } while (0)
418 #define	STATS_DEC_ACTIVE(x)	do { } while (0)
419 #define	STATS_INC_ALLOCED(x)	do { } while (0)
420 #define	STATS_INC_GROWN(x)	do { } while (0)
421 #define	STATS_ADD_REAPED(x,y)	do { } while (0)
422 #define	STATS_SET_HIGH(x)	do { } while (0)
423 #define	STATS_INC_ERR(x)	do { } while (0)
424 #define	STATS_INC_NODEALLOCS(x)	do { } while (0)
425 #define	STATS_INC_NODEFREES(x)	do { } while (0)
426 #define STATS_INC_ACOVERFLOW(x)   do { } while (0)
427 #define	STATS_SET_FREEABLE(x, i) do { } while (0)
428 #define STATS_INC_ALLOCHIT(x)	do { } while (0)
429 #define STATS_INC_ALLOCMISS(x)	do { } while (0)
430 #define STATS_INC_FREEHIT(x)	do { } while (0)
431 #define STATS_INC_FREEMISS(x)	do { } while (0)
432 #endif
433 
434 #if DEBUG
435 
436 /*
437  * memory layout of objects:
438  * 0		: objp
439  * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
440  * 		the end of an object is aligned with the end of the real
441  * 		allocation. Catches writes behind the end of the allocation.
442  * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
443  * 		redzone word.
444  * cachep->obj_offset: The real object.
445  * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
446  * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
447  *					[BYTES_PER_WORD long]
448  */
449 static int obj_offset(struct kmem_cache *cachep)
450 {
451 	return cachep->obj_offset;
452 }
453 
454 static int obj_size(struct kmem_cache *cachep)
455 {
456 	return cachep->obj_size;
457 }
458 
459 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
460 {
461 	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
462 	return (unsigned long long*) (objp + obj_offset(cachep) -
463 				      sizeof(unsigned long long));
464 }
465 
466 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
467 {
468 	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
469 	if (cachep->flags & SLAB_STORE_USER)
470 		return (unsigned long long *)(objp + cachep->buffer_size -
471 					      sizeof(unsigned long long) -
472 					      REDZONE_ALIGN);
473 	return (unsigned long long *) (objp + cachep->buffer_size -
474 				       sizeof(unsigned long long));
475 }
476 
477 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
478 {
479 	BUG_ON(!(cachep->flags & SLAB_STORE_USER));
480 	return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
481 }
482 
483 #else
484 
485 #define obj_offset(x)			0
486 #define obj_size(cachep)		(cachep->buffer_size)
487 #define dbg_redzone1(cachep, objp)	({BUG(); (unsigned long long *)NULL;})
488 #define dbg_redzone2(cachep, objp)	({BUG(); (unsigned long long *)NULL;})
489 #define dbg_userword(cachep, objp)	({BUG(); (void **)NULL;})
490 
491 #endif
492 
493 #ifdef CONFIG_KMEMTRACE
494 size_t slab_buffer_size(struct kmem_cache *cachep)
495 {
496 	return cachep->buffer_size;
497 }
498 EXPORT_SYMBOL(slab_buffer_size);
499 #endif
500 
501 /*
502  * Do not go above this order unless 0 objects fit into the slab.
503  */
504 #define	BREAK_GFP_ORDER_HI	1
505 #define	BREAK_GFP_ORDER_LO	0
506 static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
507 
508 /*
509  * Functions for storing/retrieving the cachep and or slab from the page
510  * allocator.  These are used to find the slab an obj belongs to.  With kfree(),
511  * these are used to find the cache which an obj belongs to.
512  */
513 static inline void page_set_cache(struct page *page, struct kmem_cache *cache)
514 {
515 	page->lru.next = (struct list_head *)cache;
516 }
517 
518 static inline struct kmem_cache *page_get_cache(struct page *page)
519 {
520 	page = compound_head(page);
521 	BUG_ON(!PageSlab(page));
522 	return (struct kmem_cache *)page->lru.next;
523 }
524 
525 static inline void page_set_slab(struct page *page, struct slab *slab)
526 {
527 	page->lru.prev = (struct list_head *)slab;
528 }
529 
530 static inline struct slab *page_get_slab(struct page *page)
531 {
532 	BUG_ON(!PageSlab(page));
533 	return (struct slab *)page->lru.prev;
534 }
535 
536 static inline struct kmem_cache *virt_to_cache(const void *obj)
537 {
538 	struct page *page = virt_to_head_page(obj);
539 	return page_get_cache(page);
540 }
541 
542 static inline struct slab *virt_to_slab(const void *obj)
543 {
544 	struct page *page = virt_to_head_page(obj);
545 	return page_get_slab(page);
546 }
547 
548 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
549 				 unsigned int idx)
550 {
551 	return slab->s_mem + cache->buffer_size * idx;
552 }
553 
554 /*
555  * We want to avoid an expensive divide : (offset / cache->buffer_size)
556  *   Using the fact that buffer_size is a constant for a particular cache,
557  *   we can replace (offset / cache->buffer_size) by
558  *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
559  */
560 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
561 					const struct slab *slab, void *obj)
562 {
563 	u32 offset = (obj - slab->s_mem);
564 	return reciprocal_divide(offset, cache->reciprocal_buffer_size);
565 }
566 
567 /*
568  * These are the default caches for kmalloc. Custom caches can have other sizes.
569  */
570 struct cache_sizes malloc_sizes[] = {
571 #define CACHE(x) { .cs_size = (x) },
572 #include <linux/kmalloc_sizes.h>
573 	CACHE(ULONG_MAX)
574 #undef CACHE
575 };
576 EXPORT_SYMBOL(malloc_sizes);
577 
578 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
579 struct cache_names {
580 	char *name;
581 	char *name_dma;
582 };
583 
584 static struct cache_names __initdata cache_names[] = {
585 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
586 #include <linux/kmalloc_sizes.h>
587 	{NULL,}
588 #undef CACHE
589 };
590 
591 static struct arraycache_init initarray_cache __initdata =
592     { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
593 static struct arraycache_init initarray_generic =
594     { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
595 
596 /* internal cache of cache description objs */
597 static struct kmem_cache cache_cache = {
598 	.batchcount = 1,
599 	.limit = BOOT_CPUCACHE_ENTRIES,
600 	.shared = 1,
601 	.buffer_size = sizeof(struct kmem_cache),
602 	.name = "kmem_cache",
603 };
604 
605 #define BAD_ALIEN_MAGIC 0x01020304ul
606 
607 #ifdef CONFIG_LOCKDEP
608 
609 /*
610  * Slab sometimes uses the kmalloc slabs to store the slab headers
611  * for other slabs "off slab".
612  * The locking for this is tricky in that it nests within the locks
613  * of all other slabs in a few places; to deal with this special
614  * locking we put on-slab caches into a separate lock-class.
615  *
616  * We set lock class for alien array caches which are up during init.
617  * The lock annotation will be lost if all cpus of a node goes down and
618  * then comes back up during hotplug
619  */
620 static struct lock_class_key on_slab_l3_key;
621 static struct lock_class_key on_slab_alc_key;
622 
623 static inline void init_lock_keys(void)
624 
625 {
626 	int q;
627 	struct cache_sizes *s = malloc_sizes;
628 
629 	while (s->cs_size != ULONG_MAX) {
630 		for_each_node(q) {
631 			struct array_cache **alc;
632 			int r;
633 			struct kmem_list3 *l3 = s->cs_cachep->nodelists[q];
634 			if (!l3 || OFF_SLAB(s->cs_cachep))
635 				continue;
636 			lockdep_set_class(&l3->list_lock, &on_slab_l3_key);
637 			alc = l3->alien;
638 			/*
639 			 * FIXME: This check for BAD_ALIEN_MAGIC
640 			 * should go away when common slab code is taught to
641 			 * work even without alien caches.
642 			 * Currently, non NUMA code returns BAD_ALIEN_MAGIC
643 			 * for alloc_alien_cache,
644 			 */
645 			if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
646 				continue;
647 			for_each_node(r) {
648 				if (alc[r])
649 					lockdep_set_class(&alc[r]->lock,
650 					     &on_slab_alc_key);
651 			}
652 		}
653 		s++;
654 	}
655 }
656 #else
657 static inline void init_lock_keys(void)
658 {
659 }
660 #endif
661 
662 /*
663  * Guard access to the cache-chain.
664  */
665 static DEFINE_MUTEX(cache_chain_mutex);
666 static struct list_head cache_chain;
667 
668 /*
669  * chicken and egg problem: delay the per-cpu array allocation
670  * until the general caches are up.
671  */
672 static enum {
673 	NONE,
674 	PARTIAL_AC,
675 	PARTIAL_L3,
676 	EARLY,
677 	FULL
678 } g_cpucache_up;
679 
680 /*
681  * used by boot code to determine if it can use slab based allocator
682  */
683 int slab_is_available(void)
684 {
685 	return g_cpucache_up >= EARLY;
686 }
687 
688 static DEFINE_PER_CPU(struct delayed_work, reap_work);
689 
690 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
691 {
692 	return cachep->array[smp_processor_id()];
693 }
694 
695 static inline struct kmem_cache *__find_general_cachep(size_t size,
696 							gfp_t gfpflags)
697 {
698 	struct cache_sizes *csizep = malloc_sizes;
699 
700 #if DEBUG
701 	/* This happens if someone tries to call
702 	 * kmem_cache_create(), or __kmalloc(), before
703 	 * the generic caches are initialized.
704 	 */
705 	BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
706 #endif
707 	if (!size)
708 		return ZERO_SIZE_PTR;
709 
710 	while (size > csizep->cs_size)
711 		csizep++;
712 
713 	/*
714 	 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
715 	 * has cs_{dma,}cachep==NULL. Thus no special case
716 	 * for large kmalloc calls required.
717 	 */
718 #ifdef CONFIG_ZONE_DMA
719 	if (unlikely(gfpflags & GFP_DMA))
720 		return csizep->cs_dmacachep;
721 #endif
722 	return csizep->cs_cachep;
723 }
724 
725 static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
726 {
727 	return __find_general_cachep(size, gfpflags);
728 }
729 
730 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
731 {
732 	return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
733 }
734 
735 /*
736  * Calculate the number of objects and left-over bytes for a given buffer size.
737  */
738 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
739 			   size_t align, int flags, size_t *left_over,
740 			   unsigned int *num)
741 {
742 	int nr_objs;
743 	size_t mgmt_size;
744 	size_t slab_size = PAGE_SIZE << gfporder;
745 
746 	/*
747 	 * The slab management structure can be either off the slab or
748 	 * on it. For the latter case, the memory allocated for a
749 	 * slab is used for:
750 	 *
751 	 * - The struct slab
752 	 * - One kmem_bufctl_t for each object
753 	 * - Padding to respect alignment of @align
754 	 * - @buffer_size bytes for each object
755 	 *
756 	 * If the slab management structure is off the slab, then the
757 	 * alignment will already be calculated into the size. Because
758 	 * the slabs are all pages aligned, the objects will be at the
759 	 * correct alignment when allocated.
760 	 */
761 	if (flags & CFLGS_OFF_SLAB) {
762 		mgmt_size = 0;
763 		nr_objs = slab_size / buffer_size;
764 
765 		if (nr_objs > SLAB_LIMIT)
766 			nr_objs = SLAB_LIMIT;
767 	} else {
768 		/*
769 		 * Ignore padding for the initial guess. The padding
770 		 * is at most @align-1 bytes, and @buffer_size is at
771 		 * least @align. In the worst case, this result will
772 		 * be one greater than the number of objects that fit
773 		 * into the memory allocation when taking the padding
774 		 * into account.
775 		 */
776 		nr_objs = (slab_size - sizeof(struct slab)) /
777 			  (buffer_size + sizeof(kmem_bufctl_t));
778 
779 		/*
780 		 * This calculated number will be either the right
781 		 * amount, or one greater than what we want.
782 		 */
783 		if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
784 		       > slab_size)
785 			nr_objs--;
786 
787 		if (nr_objs > SLAB_LIMIT)
788 			nr_objs = SLAB_LIMIT;
789 
790 		mgmt_size = slab_mgmt_size(nr_objs, align);
791 	}
792 	*num = nr_objs;
793 	*left_over = slab_size - nr_objs*buffer_size - mgmt_size;
794 }
795 
796 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
797 
798 static void __slab_error(const char *function, struct kmem_cache *cachep,
799 			char *msg)
800 {
801 	printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
802 	       function, cachep->name, msg);
803 	dump_stack();
804 }
805 
806 /*
807  * By default on NUMA we use alien caches to stage the freeing of
808  * objects allocated from other nodes. This causes massive memory
809  * inefficiencies when using fake NUMA setup to split memory into a
810  * large number of small nodes, so it can be disabled on the command
811  * line
812   */
813 
814 static int use_alien_caches __read_mostly = 1;
815 static int __init noaliencache_setup(char *s)
816 {
817 	use_alien_caches = 0;
818 	return 1;
819 }
820 __setup("noaliencache", noaliencache_setup);
821 
822 #ifdef CONFIG_NUMA
823 /*
824  * Special reaping functions for NUMA systems called from cache_reap().
825  * These take care of doing round robin flushing of alien caches (containing
826  * objects freed on different nodes from which they were allocated) and the
827  * flushing of remote pcps by calling drain_node_pages.
828  */
829 static DEFINE_PER_CPU(unsigned long, reap_node);
830 
831 static void init_reap_node(int cpu)
832 {
833 	int node;
834 
835 	node = next_node(cpu_to_node(cpu), node_online_map);
836 	if (node == MAX_NUMNODES)
837 		node = first_node(node_online_map);
838 
839 	per_cpu(reap_node, cpu) = node;
840 }
841 
842 static void next_reap_node(void)
843 {
844 	int node = __get_cpu_var(reap_node);
845 
846 	node = next_node(node, node_online_map);
847 	if (unlikely(node >= MAX_NUMNODES))
848 		node = first_node(node_online_map);
849 	__get_cpu_var(reap_node) = node;
850 }
851 
852 #else
853 #define init_reap_node(cpu) do { } while (0)
854 #define next_reap_node(void) do { } while (0)
855 #endif
856 
857 /*
858  * Initiate the reap timer running on the target CPU.  We run at around 1 to 2Hz
859  * via the workqueue/eventd.
860  * Add the CPU number into the expiration time to minimize the possibility of
861  * the CPUs getting into lockstep and contending for the global cache chain
862  * lock.
863  */
864 static void __cpuinit start_cpu_timer(int cpu)
865 {
866 	struct delayed_work *reap_work = &per_cpu(reap_work, cpu);
867 
868 	/*
869 	 * When this gets called from do_initcalls via cpucache_init(),
870 	 * init_workqueues() has already run, so keventd will be setup
871 	 * at that time.
872 	 */
873 	if (keventd_up() && reap_work->work.func == NULL) {
874 		init_reap_node(cpu);
875 		INIT_DELAYED_WORK(reap_work, cache_reap);
876 		schedule_delayed_work_on(cpu, reap_work,
877 					__round_jiffies_relative(HZ, cpu));
878 	}
879 }
880 
881 static struct array_cache *alloc_arraycache(int node, int entries,
882 					    int batchcount, gfp_t gfp)
883 {
884 	int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
885 	struct array_cache *nc = NULL;
886 
887 	nc = kmalloc_node(memsize, gfp, node);
888 	/*
889 	 * The array_cache structures contain pointers to free object.
890 	 * However, when such objects are allocated or transfered to another
891 	 * cache the pointers are not cleared and they could be counted as
892 	 * valid references during a kmemleak scan. Therefore, kmemleak must
893 	 * not scan such objects.
894 	 */
895 	kmemleak_no_scan(nc);
896 	if (nc) {
897 		nc->avail = 0;
898 		nc->limit = entries;
899 		nc->batchcount = batchcount;
900 		nc->touched = 0;
901 		spin_lock_init(&nc->lock);
902 	}
903 	return nc;
904 }
905 
906 /*
907  * Transfer objects in one arraycache to another.
908  * Locking must be handled by the caller.
909  *
910  * Return the number of entries transferred.
911  */
912 static int transfer_objects(struct array_cache *to,
913 		struct array_cache *from, unsigned int max)
914 {
915 	/* Figure out how many entries to transfer */
916 	int nr = min(min(from->avail, max), to->limit - to->avail);
917 
918 	if (!nr)
919 		return 0;
920 
921 	memcpy(to->entry + to->avail, from->entry + from->avail -nr,
922 			sizeof(void *) *nr);
923 
924 	from->avail -= nr;
925 	to->avail += nr;
926 	to->touched = 1;
927 	return nr;
928 }
929 
930 #ifndef CONFIG_NUMA
931 
932 #define drain_alien_cache(cachep, alien) do { } while (0)
933 #define reap_alien(cachep, l3) do { } while (0)
934 
935 static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
936 {
937 	return (struct array_cache **)BAD_ALIEN_MAGIC;
938 }
939 
940 static inline void free_alien_cache(struct array_cache **ac_ptr)
941 {
942 }
943 
944 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
945 {
946 	return 0;
947 }
948 
949 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
950 		gfp_t flags)
951 {
952 	return NULL;
953 }
954 
955 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
956 		 gfp_t flags, int nodeid)
957 {
958 	return NULL;
959 }
960 
961 #else	/* CONFIG_NUMA */
962 
963 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
964 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
965 
966 static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
967 {
968 	struct array_cache **ac_ptr;
969 	int memsize = sizeof(void *) * nr_node_ids;
970 	int i;
971 
972 	if (limit > 1)
973 		limit = 12;
974 	ac_ptr = kmalloc_node(memsize, gfp, node);
975 	if (ac_ptr) {
976 		for_each_node(i) {
977 			if (i == node || !node_online(i)) {
978 				ac_ptr[i] = NULL;
979 				continue;
980 			}
981 			ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
982 			if (!ac_ptr[i]) {
983 				for (i--; i >= 0; i--)
984 					kfree(ac_ptr[i]);
985 				kfree(ac_ptr);
986 				return NULL;
987 			}
988 		}
989 	}
990 	return ac_ptr;
991 }
992 
993 static void free_alien_cache(struct array_cache **ac_ptr)
994 {
995 	int i;
996 
997 	if (!ac_ptr)
998 		return;
999 	for_each_node(i)
1000 	    kfree(ac_ptr[i]);
1001 	kfree(ac_ptr);
1002 }
1003 
1004 static void __drain_alien_cache(struct kmem_cache *cachep,
1005 				struct array_cache *ac, int node)
1006 {
1007 	struct kmem_list3 *rl3 = cachep->nodelists[node];
1008 
1009 	if (ac->avail) {
1010 		spin_lock(&rl3->list_lock);
1011 		/*
1012 		 * Stuff objects into the remote nodes shared array first.
1013 		 * That way we could avoid the overhead of putting the objects
1014 		 * into the free lists and getting them back later.
1015 		 */
1016 		if (rl3->shared)
1017 			transfer_objects(rl3->shared, ac, ac->limit);
1018 
1019 		free_block(cachep, ac->entry, ac->avail, node);
1020 		ac->avail = 0;
1021 		spin_unlock(&rl3->list_lock);
1022 	}
1023 }
1024 
1025 /*
1026  * Called from cache_reap() to regularly drain alien caches round robin.
1027  */
1028 static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
1029 {
1030 	int node = __get_cpu_var(reap_node);
1031 
1032 	if (l3->alien) {
1033 		struct array_cache *ac = l3->alien[node];
1034 
1035 		if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1036 			__drain_alien_cache(cachep, ac, node);
1037 			spin_unlock_irq(&ac->lock);
1038 		}
1039 	}
1040 }
1041 
1042 static void drain_alien_cache(struct kmem_cache *cachep,
1043 				struct array_cache **alien)
1044 {
1045 	int i = 0;
1046 	struct array_cache *ac;
1047 	unsigned long flags;
1048 
1049 	for_each_online_node(i) {
1050 		ac = alien[i];
1051 		if (ac) {
1052 			spin_lock_irqsave(&ac->lock, flags);
1053 			__drain_alien_cache(cachep, ac, i);
1054 			spin_unlock_irqrestore(&ac->lock, flags);
1055 		}
1056 	}
1057 }
1058 
1059 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1060 {
1061 	struct slab *slabp = virt_to_slab(objp);
1062 	int nodeid = slabp->nodeid;
1063 	struct kmem_list3 *l3;
1064 	struct array_cache *alien = NULL;
1065 	int node;
1066 
1067 	node = numa_node_id();
1068 
1069 	/*
1070 	 * Make sure we are not freeing a object from another node to the array
1071 	 * cache on this cpu.
1072 	 */
1073 	if (likely(slabp->nodeid == node))
1074 		return 0;
1075 
1076 	l3 = cachep->nodelists[node];
1077 	STATS_INC_NODEFREES(cachep);
1078 	if (l3->alien && l3->alien[nodeid]) {
1079 		alien = l3->alien[nodeid];
1080 		spin_lock(&alien->lock);
1081 		if (unlikely(alien->avail == alien->limit)) {
1082 			STATS_INC_ACOVERFLOW(cachep);
1083 			__drain_alien_cache(cachep, alien, nodeid);
1084 		}
1085 		alien->entry[alien->avail++] = objp;
1086 		spin_unlock(&alien->lock);
1087 	} else {
1088 		spin_lock(&(cachep->nodelists[nodeid])->list_lock);
1089 		free_block(cachep, &objp, 1, nodeid);
1090 		spin_unlock(&(cachep->nodelists[nodeid])->list_lock);
1091 	}
1092 	return 1;
1093 }
1094 #endif
1095 
1096 static void __cpuinit cpuup_canceled(long cpu)
1097 {
1098 	struct kmem_cache *cachep;
1099 	struct kmem_list3 *l3 = NULL;
1100 	int node = cpu_to_node(cpu);
1101 	const struct cpumask *mask = cpumask_of_node(node);
1102 
1103 	list_for_each_entry(cachep, &cache_chain, next) {
1104 		struct array_cache *nc;
1105 		struct array_cache *shared;
1106 		struct array_cache **alien;
1107 
1108 		/* cpu is dead; no one can alloc from it. */
1109 		nc = cachep->array[cpu];
1110 		cachep->array[cpu] = NULL;
1111 		l3 = cachep->nodelists[node];
1112 
1113 		if (!l3)
1114 			goto free_array_cache;
1115 
1116 		spin_lock_irq(&l3->list_lock);
1117 
1118 		/* Free limit for this kmem_list3 */
1119 		l3->free_limit -= cachep->batchcount;
1120 		if (nc)
1121 			free_block(cachep, nc->entry, nc->avail, node);
1122 
1123 		if (!cpus_empty(*mask)) {
1124 			spin_unlock_irq(&l3->list_lock);
1125 			goto free_array_cache;
1126 		}
1127 
1128 		shared = l3->shared;
1129 		if (shared) {
1130 			free_block(cachep, shared->entry,
1131 				   shared->avail, node);
1132 			l3->shared = NULL;
1133 		}
1134 
1135 		alien = l3->alien;
1136 		l3->alien = NULL;
1137 
1138 		spin_unlock_irq(&l3->list_lock);
1139 
1140 		kfree(shared);
1141 		if (alien) {
1142 			drain_alien_cache(cachep, alien);
1143 			free_alien_cache(alien);
1144 		}
1145 free_array_cache:
1146 		kfree(nc);
1147 	}
1148 	/*
1149 	 * In the previous loop, all the objects were freed to
1150 	 * the respective cache's slabs,  now we can go ahead and
1151 	 * shrink each nodelist to its limit.
1152 	 */
1153 	list_for_each_entry(cachep, &cache_chain, next) {
1154 		l3 = cachep->nodelists[node];
1155 		if (!l3)
1156 			continue;
1157 		drain_freelist(cachep, l3, l3->free_objects);
1158 	}
1159 }
1160 
1161 static int __cpuinit cpuup_prepare(long cpu)
1162 {
1163 	struct kmem_cache *cachep;
1164 	struct kmem_list3 *l3 = NULL;
1165 	int node = cpu_to_node(cpu);
1166 	const int memsize = sizeof(struct kmem_list3);
1167 
1168 	/*
1169 	 * We need to do this right in the beginning since
1170 	 * alloc_arraycache's are going to use this list.
1171 	 * kmalloc_node allows us to add the slab to the right
1172 	 * kmem_list3 and not this cpu's kmem_list3
1173 	 */
1174 
1175 	list_for_each_entry(cachep, &cache_chain, next) {
1176 		/*
1177 		 * Set up the size64 kmemlist for cpu before we can
1178 		 * begin anything. Make sure some other cpu on this
1179 		 * node has not already allocated this
1180 		 */
1181 		if (!cachep->nodelists[node]) {
1182 			l3 = kmalloc_node(memsize, GFP_KERNEL, node);
1183 			if (!l3)
1184 				goto bad;
1185 			kmem_list3_init(l3);
1186 			l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1187 			    ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1188 
1189 			/*
1190 			 * The l3s don't come and go as CPUs come and
1191 			 * go.  cache_chain_mutex is sufficient
1192 			 * protection here.
1193 			 */
1194 			cachep->nodelists[node] = l3;
1195 		}
1196 
1197 		spin_lock_irq(&cachep->nodelists[node]->list_lock);
1198 		cachep->nodelists[node]->free_limit =
1199 			(1 + nr_cpus_node(node)) *
1200 			cachep->batchcount + cachep->num;
1201 		spin_unlock_irq(&cachep->nodelists[node]->list_lock);
1202 	}
1203 
1204 	/*
1205 	 * Now we can go ahead with allocating the shared arrays and
1206 	 * array caches
1207 	 */
1208 	list_for_each_entry(cachep, &cache_chain, next) {
1209 		struct array_cache *nc;
1210 		struct array_cache *shared = NULL;
1211 		struct array_cache **alien = NULL;
1212 
1213 		nc = alloc_arraycache(node, cachep->limit,
1214 					cachep->batchcount, GFP_KERNEL);
1215 		if (!nc)
1216 			goto bad;
1217 		if (cachep->shared) {
1218 			shared = alloc_arraycache(node,
1219 				cachep->shared * cachep->batchcount,
1220 				0xbaadf00d, GFP_KERNEL);
1221 			if (!shared) {
1222 				kfree(nc);
1223 				goto bad;
1224 			}
1225 		}
1226 		if (use_alien_caches) {
1227 			alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
1228 			if (!alien) {
1229 				kfree(shared);
1230 				kfree(nc);
1231 				goto bad;
1232 			}
1233 		}
1234 		cachep->array[cpu] = nc;
1235 		l3 = cachep->nodelists[node];
1236 		BUG_ON(!l3);
1237 
1238 		spin_lock_irq(&l3->list_lock);
1239 		if (!l3->shared) {
1240 			/*
1241 			 * We are serialised from CPU_DEAD or
1242 			 * CPU_UP_CANCELLED by the cpucontrol lock
1243 			 */
1244 			l3->shared = shared;
1245 			shared = NULL;
1246 		}
1247 #ifdef CONFIG_NUMA
1248 		if (!l3->alien) {
1249 			l3->alien = alien;
1250 			alien = NULL;
1251 		}
1252 #endif
1253 		spin_unlock_irq(&l3->list_lock);
1254 		kfree(shared);
1255 		free_alien_cache(alien);
1256 	}
1257 	return 0;
1258 bad:
1259 	cpuup_canceled(cpu);
1260 	return -ENOMEM;
1261 }
1262 
1263 static int __cpuinit cpuup_callback(struct notifier_block *nfb,
1264 				    unsigned long action, void *hcpu)
1265 {
1266 	long cpu = (long)hcpu;
1267 	int err = 0;
1268 
1269 	switch (action) {
1270 	case CPU_UP_PREPARE:
1271 	case CPU_UP_PREPARE_FROZEN:
1272 		mutex_lock(&cache_chain_mutex);
1273 		err = cpuup_prepare(cpu);
1274 		mutex_unlock(&cache_chain_mutex);
1275 		break;
1276 	case CPU_ONLINE:
1277 	case CPU_ONLINE_FROZEN:
1278 		start_cpu_timer(cpu);
1279 		break;
1280 #ifdef CONFIG_HOTPLUG_CPU
1281   	case CPU_DOWN_PREPARE:
1282   	case CPU_DOWN_PREPARE_FROZEN:
1283 		/*
1284 		 * Shutdown cache reaper. Note that the cache_chain_mutex is
1285 		 * held so that if cache_reap() is invoked it cannot do
1286 		 * anything expensive but will only modify reap_work
1287 		 * and reschedule the timer.
1288 		*/
1289 		cancel_rearming_delayed_work(&per_cpu(reap_work, cpu));
1290 		/* Now the cache_reaper is guaranteed to be not running. */
1291 		per_cpu(reap_work, cpu).work.func = NULL;
1292   		break;
1293   	case CPU_DOWN_FAILED:
1294   	case CPU_DOWN_FAILED_FROZEN:
1295 		start_cpu_timer(cpu);
1296   		break;
1297 	case CPU_DEAD:
1298 	case CPU_DEAD_FROZEN:
1299 		/*
1300 		 * Even if all the cpus of a node are down, we don't free the
1301 		 * kmem_list3 of any cache. This to avoid a race between
1302 		 * cpu_down, and a kmalloc allocation from another cpu for
1303 		 * memory from the node of the cpu going down.  The list3
1304 		 * structure is usually allocated from kmem_cache_create() and
1305 		 * gets destroyed at kmem_cache_destroy().
1306 		 */
1307 		/* fall through */
1308 #endif
1309 	case CPU_UP_CANCELED:
1310 	case CPU_UP_CANCELED_FROZEN:
1311 		mutex_lock(&cache_chain_mutex);
1312 		cpuup_canceled(cpu);
1313 		mutex_unlock(&cache_chain_mutex);
1314 		break;
1315 	}
1316 	return err ? NOTIFY_BAD : NOTIFY_OK;
1317 }
1318 
1319 static struct notifier_block __cpuinitdata cpucache_notifier = {
1320 	&cpuup_callback, NULL, 0
1321 };
1322 
1323 /*
1324  * swap the static kmem_list3 with kmalloced memory
1325  */
1326 static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
1327 			int nodeid)
1328 {
1329 	struct kmem_list3 *ptr;
1330 
1331 	ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_NOWAIT, nodeid);
1332 	BUG_ON(!ptr);
1333 
1334 	memcpy(ptr, list, sizeof(struct kmem_list3));
1335 	/*
1336 	 * Do not assume that spinlocks can be initialized via memcpy:
1337 	 */
1338 	spin_lock_init(&ptr->list_lock);
1339 
1340 	MAKE_ALL_LISTS(cachep, ptr, nodeid);
1341 	cachep->nodelists[nodeid] = ptr;
1342 }
1343 
1344 /*
1345  * For setting up all the kmem_list3s for cache whose buffer_size is same as
1346  * size of kmem_list3.
1347  */
1348 static void __init set_up_list3s(struct kmem_cache *cachep, int index)
1349 {
1350 	int node;
1351 
1352 	for_each_online_node(node) {
1353 		cachep->nodelists[node] = &initkmem_list3[index + node];
1354 		cachep->nodelists[node]->next_reap = jiffies +
1355 		    REAPTIMEOUT_LIST3 +
1356 		    ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1357 	}
1358 }
1359 
1360 /*
1361  * Initialisation.  Called after the page allocator have been initialised and
1362  * before smp_init().
1363  */
1364 void __init kmem_cache_init(void)
1365 {
1366 	size_t left_over;
1367 	struct cache_sizes *sizes;
1368 	struct cache_names *names;
1369 	int i;
1370 	int order;
1371 	int node;
1372 
1373 	if (num_possible_nodes() == 1)
1374 		use_alien_caches = 0;
1375 
1376 	for (i = 0; i < NUM_INIT_LISTS; i++) {
1377 		kmem_list3_init(&initkmem_list3[i]);
1378 		if (i < MAX_NUMNODES)
1379 			cache_cache.nodelists[i] = NULL;
1380 	}
1381 	set_up_list3s(&cache_cache, CACHE_CACHE);
1382 
1383 	/*
1384 	 * Fragmentation resistance on low memory - only use bigger
1385 	 * page orders on machines with more than 32MB of memory.
1386 	 */
1387 	if (totalram_pages > (32 << 20) >> PAGE_SHIFT)
1388 		slab_break_gfp_order = BREAK_GFP_ORDER_HI;
1389 
1390 	/* Bootstrap is tricky, because several objects are allocated
1391 	 * from caches that do not exist yet:
1392 	 * 1) initialize the cache_cache cache: it contains the struct
1393 	 *    kmem_cache structures of all caches, except cache_cache itself:
1394 	 *    cache_cache is statically allocated.
1395 	 *    Initially an __init data area is used for the head array and the
1396 	 *    kmem_list3 structures, it's replaced with a kmalloc allocated
1397 	 *    array at the end of the bootstrap.
1398 	 * 2) Create the first kmalloc cache.
1399 	 *    The struct kmem_cache for the new cache is allocated normally.
1400 	 *    An __init data area is used for the head array.
1401 	 * 3) Create the remaining kmalloc caches, with minimally sized
1402 	 *    head arrays.
1403 	 * 4) Replace the __init data head arrays for cache_cache and the first
1404 	 *    kmalloc cache with kmalloc allocated arrays.
1405 	 * 5) Replace the __init data for kmem_list3 for cache_cache and
1406 	 *    the other cache's with kmalloc allocated memory.
1407 	 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1408 	 */
1409 
1410 	node = numa_node_id();
1411 
1412 	/* 1) create the cache_cache */
1413 	INIT_LIST_HEAD(&cache_chain);
1414 	list_add(&cache_cache.next, &cache_chain);
1415 	cache_cache.colour_off = cache_line_size();
1416 	cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
1417 	cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node];
1418 
1419 	/*
1420 	 * struct kmem_cache size depends on nr_node_ids, which
1421 	 * can be less than MAX_NUMNODES.
1422 	 */
1423 	cache_cache.buffer_size = offsetof(struct kmem_cache, nodelists) +
1424 				 nr_node_ids * sizeof(struct kmem_list3 *);
1425 #if DEBUG
1426 	cache_cache.obj_size = cache_cache.buffer_size;
1427 #endif
1428 	cache_cache.buffer_size = ALIGN(cache_cache.buffer_size,
1429 					cache_line_size());
1430 	cache_cache.reciprocal_buffer_size =
1431 		reciprocal_value(cache_cache.buffer_size);
1432 
1433 	for (order = 0; order < MAX_ORDER; order++) {
1434 		cache_estimate(order, cache_cache.buffer_size,
1435 			cache_line_size(), 0, &left_over, &cache_cache.num);
1436 		if (cache_cache.num)
1437 			break;
1438 	}
1439 	BUG_ON(!cache_cache.num);
1440 	cache_cache.gfporder = order;
1441 	cache_cache.colour = left_over / cache_cache.colour_off;
1442 	cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
1443 				      sizeof(struct slab), cache_line_size());
1444 
1445 	/* 2+3) create the kmalloc caches */
1446 	sizes = malloc_sizes;
1447 	names = cache_names;
1448 
1449 	/*
1450 	 * Initialize the caches that provide memory for the array cache and the
1451 	 * kmem_list3 structures first.  Without this, further allocations will
1452 	 * bug.
1453 	 */
1454 
1455 	sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name,
1456 					sizes[INDEX_AC].cs_size,
1457 					ARCH_KMALLOC_MINALIGN,
1458 					ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1459 					NULL);
1460 
1461 	if (INDEX_AC != INDEX_L3) {
1462 		sizes[INDEX_L3].cs_cachep =
1463 			kmem_cache_create(names[INDEX_L3].name,
1464 				sizes[INDEX_L3].cs_size,
1465 				ARCH_KMALLOC_MINALIGN,
1466 				ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1467 				NULL);
1468 	}
1469 
1470 	slab_early_init = 0;
1471 
1472 	while (sizes->cs_size != ULONG_MAX) {
1473 		/*
1474 		 * For performance, all the general caches are L1 aligned.
1475 		 * This should be particularly beneficial on SMP boxes, as it
1476 		 * eliminates "false sharing".
1477 		 * Note for systems short on memory removing the alignment will
1478 		 * allow tighter packing of the smaller caches.
1479 		 */
1480 		if (!sizes->cs_cachep) {
1481 			sizes->cs_cachep = kmem_cache_create(names->name,
1482 					sizes->cs_size,
1483 					ARCH_KMALLOC_MINALIGN,
1484 					ARCH_KMALLOC_FLAGS|SLAB_PANIC,
1485 					NULL);
1486 		}
1487 #ifdef CONFIG_ZONE_DMA
1488 		sizes->cs_dmacachep = kmem_cache_create(
1489 					names->name_dma,
1490 					sizes->cs_size,
1491 					ARCH_KMALLOC_MINALIGN,
1492 					ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
1493 						SLAB_PANIC,
1494 					NULL);
1495 #endif
1496 		sizes++;
1497 		names++;
1498 	}
1499 	/* 4) Replace the bootstrap head arrays */
1500 	{
1501 		struct array_cache *ptr;
1502 
1503 		ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1504 
1505 		BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
1506 		memcpy(ptr, cpu_cache_get(&cache_cache),
1507 		       sizeof(struct arraycache_init));
1508 		/*
1509 		 * Do not assume that spinlocks can be initialized via memcpy:
1510 		 */
1511 		spin_lock_init(&ptr->lock);
1512 
1513 		cache_cache.array[smp_processor_id()] = ptr;
1514 
1515 		ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
1516 
1517 		BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
1518 		       != &initarray_generic.cache);
1519 		memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
1520 		       sizeof(struct arraycache_init));
1521 		/*
1522 		 * Do not assume that spinlocks can be initialized via memcpy:
1523 		 */
1524 		spin_lock_init(&ptr->lock);
1525 
1526 		malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
1527 		    ptr;
1528 	}
1529 	/* 5) Replace the bootstrap kmem_list3's */
1530 	{
1531 		int nid;
1532 
1533 		for_each_online_node(nid) {
1534 			init_list(&cache_cache, &initkmem_list3[CACHE_CACHE + nid], nid);
1535 
1536 			init_list(malloc_sizes[INDEX_AC].cs_cachep,
1537 				  &initkmem_list3[SIZE_AC + nid], nid);
1538 
1539 			if (INDEX_AC != INDEX_L3) {
1540 				init_list(malloc_sizes[INDEX_L3].cs_cachep,
1541 					  &initkmem_list3[SIZE_L3 + nid], nid);
1542 			}
1543 		}
1544 	}
1545 
1546 	g_cpucache_up = EARLY;
1547 }
1548 
1549 void __init kmem_cache_init_late(void)
1550 {
1551 	struct kmem_cache *cachep;
1552 
1553 	/* 6) resize the head arrays to their final sizes */
1554 	mutex_lock(&cache_chain_mutex);
1555 	list_for_each_entry(cachep, &cache_chain, next)
1556 		if (enable_cpucache(cachep, GFP_NOWAIT))
1557 			BUG();
1558 	mutex_unlock(&cache_chain_mutex);
1559 
1560 	/* Done! */
1561 	g_cpucache_up = FULL;
1562 
1563 	/* Annotate slab for lockdep -- annotate the malloc caches */
1564 	init_lock_keys();
1565 
1566 	/*
1567 	 * Register a cpu startup notifier callback that initializes
1568 	 * cpu_cache_get for all new cpus
1569 	 */
1570 	register_cpu_notifier(&cpucache_notifier);
1571 
1572 	/*
1573 	 * The reap timers are started later, with a module init call: That part
1574 	 * of the kernel is not yet operational.
1575 	 */
1576 }
1577 
1578 static int __init cpucache_init(void)
1579 {
1580 	int cpu;
1581 
1582 	/*
1583 	 * Register the timers that return unneeded pages to the page allocator
1584 	 */
1585 	for_each_online_cpu(cpu)
1586 		start_cpu_timer(cpu);
1587 	return 0;
1588 }
1589 __initcall(cpucache_init);
1590 
1591 /*
1592  * Interface to system's page allocator. No need to hold the cache-lock.
1593  *
1594  * If we requested dmaable memory, we will get it. Even if we
1595  * did not request dmaable memory, we might get it, but that
1596  * would be relatively rare and ignorable.
1597  */
1598 static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
1599 {
1600 	struct page *page;
1601 	int nr_pages;
1602 	int i;
1603 
1604 #ifndef CONFIG_MMU
1605 	/*
1606 	 * Nommu uses slab's for process anonymous memory allocations, and thus
1607 	 * requires __GFP_COMP to properly refcount higher order allocations
1608 	 */
1609 	flags |= __GFP_COMP;
1610 #endif
1611 
1612 	flags |= cachep->gfpflags;
1613 	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1614 		flags |= __GFP_RECLAIMABLE;
1615 
1616 	page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1617 	if (!page)
1618 		return NULL;
1619 
1620 	nr_pages = (1 << cachep->gfporder);
1621 	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1622 		add_zone_page_state(page_zone(page),
1623 			NR_SLAB_RECLAIMABLE, nr_pages);
1624 	else
1625 		add_zone_page_state(page_zone(page),
1626 			NR_SLAB_UNRECLAIMABLE, nr_pages);
1627 	for (i = 0; i < nr_pages; i++)
1628 		__SetPageSlab(page + i);
1629 
1630 	if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1631 		kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1632 
1633 		if (cachep->ctor)
1634 			kmemcheck_mark_uninitialized_pages(page, nr_pages);
1635 		else
1636 			kmemcheck_mark_unallocated_pages(page, nr_pages);
1637 	}
1638 
1639 	return page_address(page);
1640 }
1641 
1642 /*
1643  * Interface to system's page release.
1644  */
1645 static void kmem_freepages(struct kmem_cache *cachep, void *addr)
1646 {
1647 	unsigned long i = (1 << cachep->gfporder);
1648 	struct page *page = virt_to_page(addr);
1649 	const unsigned long nr_freed = i;
1650 
1651 	kmemcheck_free_shadow(page, cachep->gfporder);
1652 
1653 	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1654 		sub_zone_page_state(page_zone(page),
1655 				NR_SLAB_RECLAIMABLE, nr_freed);
1656 	else
1657 		sub_zone_page_state(page_zone(page),
1658 				NR_SLAB_UNRECLAIMABLE, nr_freed);
1659 	while (i--) {
1660 		BUG_ON(!PageSlab(page));
1661 		__ClearPageSlab(page);
1662 		page++;
1663 	}
1664 	if (current->reclaim_state)
1665 		current->reclaim_state->reclaimed_slab += nr_freed;
1666 	free_pages((unsigned long)addr, cachep->gfporder);
1667 }
1668 
1669 static void kmem_rcu_free(struct rcu_head *head)
1670 {
1671 	struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
1672 	struct kmem_cache *cachep = slab_rcu->cachep;
1673 
1674 	kmem_freepages(cachep, slab_rcu->addr);
1675 	if (OFF_SLAB(cachep))
1676 		kmem_cache_free(cachep->slabp_cache, slab_rcu);
1677 }
1678 
1679 #if DEBUG
1680 
1681 #ifdef CONFIG_DEBUG_PAGEALLOC
1682 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1683 			    unsigned long caller)
1684 {
1685 	int size = obj_size(cachep);
1686 
1687 	addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1688 
1689 	if (size < 5 * sizeof(unsigned long))
1690 		return;
1691 
1692 	*addr++ = 0x12345678;
1693 	*addr++ = caller;
1694 	*addr++ = smp_processor_id();
1695 	size -= 3 * sizeof(unsigned long);
1696 	{
1697 		unsigned long *sptr = &caller;
1698 		unsigned long svalue;
1699 
1700 		while (!kstack_end(sptr)) {
1701 			svalue = *sptr++;
1702 			if (kernel_text_address(svalue)) {
1703 				*addr++ = svalue;
1704 				size -= sizeof(unsigned long);
1705 				if (size <= sizeof(unsigned long))
1706 					break;
1707 			}
1708 		}
1709 
1710 	}
1711 	*addr++ = 0x87654321;
1712 }
1713 #endif
1714 
1715 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1716 {
1717 	int size = obj_size(cachep);
1718 	addr = &((char *)addr)[obj_offset(cachep)];
1719 
1720 	memset(addr, val, size);
1721 	*(unsigned char *)(addr + size - 1) = POISON_END;
1722 }
1723 
1724 static void dump_line(char *data, int offset, int limit)
1725 {
1726 	int i;
1727 	unsigned char error = 0;
1728 	int bad_count = 0;
1729 
1730 	printk(KERN_ERR "%03x:", offset);
1731 	for (i = 0; i < limit; i++) {
1732 		if (data[offset + i] != POISON_FREE) {
1733 			error = data[offset + i];
1734 			bad_count++;
1735 		}
1736 		printk(" %02x", (unsigned char)data[offset + i]);
1737 	}
1738 	printk("\n");
1739 
1740 	if (bad_count == 1) {
1741 		error ^= POISON_FREE;
1742 		if (!(error & (error - 1))) {
1743 			printk(KERN_ERR "Single bit error detected. Probably "
1744 					"bad RAM.\n");
1745 #ifdef CONFIG_X86
1746 			printk(KERN_ERR "Run memtest86+ or a similar memory "
1747 					"test tool.\n");
1748 #else
1749 			printk(KERN_ERR "Run a memory test tool.\n");
1750 #endif
1751 		}
1752 	}
1753 }
1754 #endif
1755 
1756 #if DEBUG
1757 
1758 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1759 {
1760 	int i, size;
1761 	char *realobj;
1762 
1763 	if (cachep->flags & SLAB_RED_ZONE) {
1764 		printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n",
1765 			*dbg_redzone1(cachep, objp),
1766 			*dbg_redzone2(cachep, objp));
1767 	}
1768 
1769 	if (cachep->flags & SLAB_STORE_USER) {
1770 		printk(KERN_ERR "Last user: [<%p>]",
1771 			*dbg_userword(cachep, objp));
1772 		print_symbol("(%s)",
1773 				(unsigned long)*dbg_userword(cachep, objp));
1774 		printk("\n");
1775 	}
1776 	realobj = (char *)objp + obj_offset(cachep);
1777 	size = obj_size(cachep);
1778 	for (i = 0; i < size && lines; i += 16, lines--) {
1779 		int limit;
1780 		limit = 16;
1781 		if (i + limit > size)
1782 			limit = size - i;
1783 		dump_line(realobj, i, limit);
1784 	}
1785 }
1786 
1787 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1788 {
1789 	char *realobj;
1790 	int size, i;
1791 	int lines = 0;
1792 
1793 	realobj = (char *)objp + obj_offset(cachep);
1794 	size = obj_size(cachep);
1795 
1796 	for (i = 0; i < size; i++) {
1797 		char exp = POISON_FREE;
1798 		if (i == size - 1)
1799 			exp = POISON_END;
1800 		if (realobj[i] != exp) {
1801 			int limit;
1802 			/* Mismatch ! */
1803 			/* Print header */
1804 			if (lines == 0) {
1805 				printk(KERN_ERR
1806 					"Slab corruption: %s start=%p, len=%d\n",
1807 					cachep->name, realobj, size);
1808 				print_objinfo(cachep, objp, 0);
1809 			}
1810 			/* Hexdump the affected line */
1811 			i = (i / 16) * 16;
1812 			limit = 16;
1813 			if (i + limit > size)
1814 				limit = size - i;
1815 			dump_line(realobj, i, limit);
1816 			i += 16;
1817 			lines++;
1818 			/* Limit to 5 lines */
1819 			if (lines > 5)
1820 				break;
1821 		}
1822 	}
1823 	if (lines != 0) {
1824 		/* Print some data about the neighboring objects, if they
1825 		 * exist:
1826 		 */
1827 		struct slab *slabp = virt_to_slab(objp);
1828 		unsigned int objnr;
1829 
1830 		objnr = obj_to_index(cachep, slabp, objp);
1831 		if (objnr) {
1832 			objp = index_to_obj(cachep, slabp, objnr - 1);
1833 			realobj = (char *)objp + obj_offset(cachep);
1834 			printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1835 			       realobj, size);
1836 			print_objinfo(cachep, objp, 2);
1837 		}
1838 		if (objnr + 1 < cachep->num) {
1839 			objp = index_to_obj(cachep, slabp, objnr + 1);
1840 			realobj = (char *)objp + obj_offset(cachep);
1841 			printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1842 			       realobj, size);
1843 			print_objinfo(cachep, objp, 2);
1844 		}
1845 	}
1846 }
1847 #endif
1848 
1849 #if DEBUG
1850 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
1851 {
1852 	int i;
1853 	for (i = 0; i < cachep->num; i++) {
1854 		void *objp = index_to_obj(cachep, slabp, i);
1855 
1856 		if (cachep->flags & SLAB_POISON) {
1857 #ifdef CONFIG_DEBUG_PAGEALLOC
1858 			if (cachep->buffer_size % PAGE_SIZE == 0 &&
1859 					OFF_SLAB(cachep))
1860 				kernel_map_pages(virt_to_page(objp),
1861 					cachep->buffer_size / PAGE_SIZE, 1);
1862 			else
1863 				check_poison_obj(cachep, objp);
1864 #else
1865 			check_poison_obj(cachep, objp);
1866 #endif
1867 		}
1868 		if (cachep->flags & SLAB_RED_ZONE) {
1869 			if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1870 				slab_error(cachep, "start of a freed object "
1871 					   "was overwritten");
1872 			if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1873 				slab_error(cachep, "end of a freed object "
1874 					   "was overwritten");
1875 		}
1876 	}
1877 }
1878 #else
1879 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
1880 {
1881 }
1882 #endif
1883 
1884 /**
1885  * slab_destroy - destroy and release all objects in a slab
1886  * @cachep: cache pointer being destroyed
1887  * @slabp: slab pointer being destroyed
1888  *
1889  * Destroy all the objs in a slab, and release the mem back to the system.
1890  * Before calling the slab must have been unlinked from the cache.  The
1891  * cache-lock is not held/needed.
1892  */
1893 static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
1894 {
1895 	void *addr = slabp->s_mem - slabp->colouroff;
1896 
1897 	slab_destroy_debugcheck(cachep, slabp);
1898 	if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
1899 		struct slab_rcu *slab_rcu;
1900 
1901 		slab_rcu = (struct slab_rcu *)slabp;
1902 		slab_rcu->cachep = cachep;
1903 		slab_rcu->addr = addr;
1904 		call_rcu(&slab_rcu->head, kmem_rcu_free);
1905 	} else {
1906 		kmem_freepages(cachep, addr);
1907 		if (OFF_SLAB(cachep))
1908 			kmem_cache_free(cachep->slabp_cache, slabp);
1909 	}
1910 }
1911 
1912 static void __kmem_cache_destroy(struct kmem_cache *cachep)
1913 {
1914 	int i;
1915 	struct kmem_list3 *l3;
1916 
1917 	for_each_online_cpu(i)
1918 	    kfree(cachep->array[i]);
1919 
1920 	/* NUMA: free the list3 structures */
1921 	for_each_online_node(i) {
1922 		l3 = cachep->nodelists[i];
1923 		if (l3) {
1924 			kfree(l3->shared);
1925 			free_alien_cache(l3->alien);
1926 			kfree(l3);
1927 		}
1928 	}
1929 	kmem_cache_free(&cache_cache, cachep);
1930 }
1931 
1932 
1933 /**
1934  * calculate_slab_order - calculate size (page order) of slabs
1935  * @cachep: pointer to the cache that is being created
1936  * @size: size of objects to be created in this cache.
1937  * @align: required alignment for the objects.
1938  * @flags: slab allocation flags
1939  *
1940  * Also calculates the number of objects per slab.
1941  *
1942  * This could be made much more intelligent.  For now, try to avoid using
1943  * high order pages for slabs.  When the gfp() functions are more friendly
1944  * towards high-order requests, this should be changed.
1945  */
1946 static size_t calculate_slab_order(struct kmem_cache *cachep,
1947 			size_t size, size_t align, unsigned long flags)
1948 {
1949 	unsigned long offslab_limit;
1950 	size_t left_over = 0;
1951 	int gfporder;
1952 
1953 	for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
1954 		unsigned int num;
1955 		size_t remainder;
1956 
1957 		cache_estimate(gfporder, size, align, flags, &remainder, &num);
1958 		if (!num)
1959 			continue;
1960 
1961 		if (flags & CFLGS_OFF_SLAB) {
1962 			/*
1963 			 * Max number of objs-per-slab for caches which
1964 			 * use off-slab slabs. Needed to avoid a possible
1965 			 * looping condition in cache_grow().
1966 			 */
1967 			offslab_limit = size - sizeof(struct slab);
1968 			offslab_limit /= sizeof(kmem_bufctl_t);
1969 
1970  			if (num > offslab_limit)
1971 				break;
1972 		}
1973 
1974 		/* Found something acceptable - save it away */
1975 		cachep->num = num;
1976 		cachep->gfporder = gfporder;
1977 		left_over = remainder;
1978 
1979 		/*
1980 		 * A VFS-reclaimable slab tends to have most allocations
1981 		 * as GFP_NOFS and we really don't want to have to be allocating
1982 		 * higher-order pages when we are unable to shrink dcache.
1983 		 */
1984 		if (flags & SLAB_RECLAIM_ACCOUNT)
1985 			break;
1986 
1987 		/*
1988 		 * Large number of objects is good, but very large slabs are
1989 		 * currently bad for the gfp()s.
1990 		 */
1991 		if (gfporder >= slab_break_gfp_order)
1992 			break;
1993 
1994 		/*
1995 		 * Acceptable internal fragmentation?
1996 		 */
1997 		if (left_over * 8 <= (PAGE_SIZE << gfporder))
1998 			break;
1999 	}
2000 	return left_over;
2001 }
2002 
2003 static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
2004 {
2005 	if (g_cpucache_up == FULL)
2006 		return enable_cpucache(cachep, gfp);
2007 
2008 	if (g_cpucache_up == NONE) {
2009 		/*
2010 		 * Note: the first kmem_cache_create must create the cache
2011 		 * that's used by kmalloc(24), otherwise the creation of
2012 		 * further caches will BUG().
2013 		 */
2014 		cachep->array[smp_processor_id()] = &initarray_generic.cache;
2015 
2016 		/*
2017 		 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
2018 		 * the first cache, then we need to set up all its list3s,
2019 		 * otherwise the creation of further caches will BUG().
2020 		 */
2021 		set_up_list3s(cachep, SIZE_AC);
2022 		if (INDEX_AC == INDEX_L3)
2023 			g_cpucache_up = PARTIAL_L3;
2024 		else
2025 			g_cpucache_up = PARTIAL_AC;
2026 	} else {
2027 		cachep->array[smp_processor_id()] =
2028 			kmalloc(sizeof(struct arraycache_init), gfp);
2029 
2030 		if (g_cpucache_up == PARTIAL_AC) {
2031 			set_up_list3s(cachep, SIZE_L3);
2032 			g_cpucache_up = PARTIAL_L3;
2033 		} else {
2034 			int node;
2035 			for_each_online_node(node) {
2036 				cachep->nodelists[node] =
2037 				    kmalloc_node(sizeof(struct kmem_list3),
2038 						gfp, node);
2039 				BUG_ON(!cachep->nodelists[node]);
2040 				kmem_list3_init(cachep->nodelists[node]);
2041 			}
2042 		}
2043 	}
2044 	cachep->nodelists[numa_node_id()]->next_reap =
2045 			jiffies + REAPTIMEOUT_LIST3 +
2046 			((unsigned long)cachep) % REAPTIMEOUT_LIST3;
2047 
2048 	cpu_cache_get(cachep)->avail = 0;
2049 	cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
2050 	cpu_cache_get(cachep)->batchcount = 1;
2051 	cpu_cache_get(cachep)->touched = 0;
2052 	cachep->batchcount = 1;
2053 	cachep->limit = BOOT_CPUCACHE_ENTRIES;
2054 	return 0;
2055 }
2056 
2057 /**
2058  * kmem_cache_create - Create a cache.
2059  * @name: A string which is used in /proc/slabinfo to identify this cache.
2060  * @size: The size of objects to be created in this cache.
2061  * @align: The required alignment for the objects.
2062  * @flags: SLAB flags
2063  * @ctor: A constructor for the objects.
2064  *
2065  * Returns a ptr to the cache on success, NULL on failure.
2066  * Cannot be called within a int, but can be interrupted.
2067  * The @ctor is run when new pages are allocated by the cache.
2068  *
2069  * @name must be valid until the cache is destroyed. This implies that
2070  * the module calling this has to destroy the cache before getting unloaded.
2071  * Note that kmem_cache_name() is not guaranteed to return the same pointer,
2072  * therefore applications must manage it themselves.
2073  *
2074  * The flags are
2075  *
2076  * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2077  * to catch references to uninitialised memory.
2078  *
2079  * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2080  * for buffer overruns.
2081  *
2082  * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2083  * cacheline.  This can be beneficial if you're counting cycles as closely
2084  * as davem.
2085  */
2086 struct kmem_cache *
2087 kmem_cache_create (const char *name, size_t size, size_t align,
2088 	unsigned long flags, void (*ctor)(void *))
2089 {
2090 	size_t left_over, slab_size, ralign;
2091 	struct kmem_cache *cachep = NULL, *pc;
2092 	gfp_t gfp;
2093 
2094 	/*
2095 	 * Sanity checks... these are all serious usage bugs.
2096 	 */
2097 	if (!name || in_interrupt() || (size < BYTES_PER_WORD) ||
2098 	    size > KMALLOC_MAX_SIZE) {
2099 		printk(KERN_ERR "%s: Early error in slab %s\n", __func__,
2100 				name);
2101 		BUG();
2102 	}
2103 
2104 	/*
2105 	 * We use cache_chain_mutex to ensure a consistent view of
2106 	 * cpu_online_mask as well.  Please see cpuup_callback
2107 	 */
2108 	if (slab_is_available()) {
2109 		get_online_cpus();
2110 		mutex_lock(&cache_chain_mutex);
2111 	}
2112 
2113 	list_for_each_entry(pc, &cache_chain, next) {
2114 		char tmp;
2115 		int res;
2116 
2117 		/*
2118 		 * This happens when the module gets unloaded and doesn't
2119 		 * destroy its slab cache and no-one else reuses the vmalloc
2120 		 * area of the module.  Print a warning.
2121 		 */
2122 		res = probe_kernel_address(pc->name, tmp);
2123 		if (res) {
2124 			printk(KERN_ERR
2125 			       "SLAB: cache with size %d has lost its name\n",
2126 			       pc->buffer_size);
2127 			continue;
2128 		}
2129 
2130 		if (!strcmp(pc->name, name)) {
2131 			printk(KERN_ERR
2132 			       "kmem_cache_create: duplicate cache %s\n", name);
2133 			dump_stack();
2134 			goto oops;
2135 		}
2136 	}
2137 
2138 #if DEBUG
2139 	WARN_ON(strchr(name, ' '));	/* It confuses parsers */
2140 #if FORCED_DEBUG
2141 	/*
2142 	 * Enable redzoning and last user accounting, except for caches with
2143 	 * large objects, if the increased size would increase the object size
2144 	 * above the next power of two: caches with object sizes just above a
2145 	 * power of two have a significant amount of internal fragmentation.
2146 	 */
2147 	if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2148 						2 * sizeof(unsigned long long)))
2149 		flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2150 	if (!(flags & SLAB_DESTROY_BY_RCU))
2151 		flags |= SLAB_POISON;
2152 #endif
2153 	if (flags & SLAB_DESTROY_BY_RCU)
2154 		BUG_ON(flags & SLAB_POISON);
2155 #endif
2156 	/*
2157 	 * Always checks flags, a caller might be expecting debug support which
2158 	 * isn't available.
2159 	 */
2160 	BUG_ON(flags & ~CREATE_MASK);
2161 
2162 	/*
2163 	 * Check that size is in terms of words.  This is needed to avoid
2164 	 * unaligned accesses for some archs when redzoning is used, and makes
2165 	 * sure any on-slab bufctl's are also correctly aligned.
2166 	 */
2167 	if (size & (BYTES_PER_WORD - 1)) {
2168 		size += (BYTES_PER_WORD - 1);
2169 		size &= ~(BYTES_PER_WORD - 1);
2170 	}
2171 
2172 	/* calculate the final buffer alignment: */
2173 
2174 	/* 1) arch recommendation: can be overridden for debug */
2175 	if (flags & SLAB_HWCACHE_ALIGN) {
2176 		/*
2177 		 * Default alignment: as specified by the arch code.  Except if
2178 		 * an object is really small, then squeeze multiple objects into
2179 		 * one cacheline.
2180 		 */
2181 		ralign = cache_line_size();
2182 		while (size <= ralign / 2)
2183 			ralign /= 2;
2184 	} else {
2185 		ralign = BYTES_PER_WORD;
2186 	}
2187 
2188 	/*
2189 	 * Redzoning and user store require word alignment or possibly larger.
2190 	 * Note this will be overridden by architecture or caller mandated
2191 	 * alignment if either is greater than BYTES_PER_WORD.
2192 	 */
2193 	if (flags & SLAB_STORE_USER)
2194 		ralign = BYTES_PER_WORD;
2195 
2196 	if (flags & SLAB_RED_ZONE) {
2197 		ralign = REDZONE_ALIGN;
2198 		/* If redzoning, ensure that the second redzone is suitably
2199 		 * aligned, by adjusting the object size accordingly. */
2200 		size += REDZONE_ALIGN - 1;
2201 		size &= ~(REDZONE_ALIGN - 1);
2202 	}
2203 
2204 	/* 2) arch mandated alignment */
2205 	if (ralign < ARCH_SLAB_MINALIGN) {
2206 		ralign = ARCH_SLAB_MINALIGN;
2207 	}
2208 	/* 3) caller mandated alignment */
2209 	if (ralign < align) {
2210 		ralign = align;
2211 	}
2212 	/* disable debug if necessary */
2213 	if (ralign > __alignof__(unsigned long long))
2214 		flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2215 	/*
2216 	 * 4) Store it.
2217 	 */
2218 	align = ralign;
2219 
2220 	if (slab_is_available())
2221 		gfp = GFP_KERNEL;
2222 	else
2223 		gfp = GFP_NOWAIT;
2224 
2225 	/* Get cache's description obj. */
2226 	cachep = kmem_cache_zalloc(&cache_cache, gfp);
2227 	if (!cachep)
2228 		goto oops;
2229 
2230 #if DEBUG
2231 	cachep->obj_size = size;
2232 
2233 	/*
2234 	 * Both debugging options require word-alignment which is calculated
2235 	 * into align above.
2236 	 */
2237 	if (flags & SLAB_RED_ZONE) {
2238 		/* add space for red zone words */
2239 		cachep->obj_offset += sizeof(unsigned long long);
2240 		size += 2 * sizeof(unsigned long long);
2241 	}
2242 	if (flags & SLAB_STORE_USER) {
2243 		/* user store requires one word storage behind the end of
2244 		 * the real object. But if the second red zone needs to be
2245 		 * aligned to 64 bits, we must allow that much space.
2246 		 */
2247 		if (flags & SLAB_RED_ZONE)
2248 			size += REDZONE_ALIGN;
2249 		else
2250 			size += BYTES_PER_WORD;
2251 	}
2252 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2253 	if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
2254 	    && cachep->obj_size > cache_line_size() && size < PAGE_SIZE) {
2255 		cachep->obj_offset += PAGE_SIZE - size;
2256 		size = PAGE_SIZE;
2257 	}
2258 #endif
2259 #endif
2260 
2261 	/*
2262 	 * Determine if the slab management is 'on' or 'off' slab.
2263 	 * (bootstrapping cannot cope with offslab caches so don't do
2264 	 * it too early on.)
2265 	 */
2266 	if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init)
2267 		/*
2268 		 * Size is large, assume best to place the slab management obj
2269 		 * off-slab (should allow better packing of objs).
2270 		 */
2271 		flags |= CFLGS_OFF_SLAB;
2272 
2273 	size = ALIGN(size, align);
2274 
2275 	left_over = calculate_slab_order(cachep, size, align, flags);
2276 
2277 	if (!cachep->num) {
2278 		printk(KERN_ERR
2279 		       "kmem_cache_create: couldn't create cache %s.\n", name);
2280 		kmem_cache_free(&cache_cache, cachep);
2281 		cachep = NULL;
2282 		goto oops;
2283 	}
2284 	slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
2285 			  + sizeof(struct slab), align);
2286 
2287 	/*
2288 	 * If the slab has been placed off-slab, and we have enough space then
2289 	 * move it on-slab. This is at the expense of any extra colouring.
2290 	 */
2291 	if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
2292 		flags &= ~CFLGS_OFF_SLAB;
2293 		left_over -= slab_size;
2294 	}
2295 
2296 	if (flags & CFLGS_OFF_SLAB) {
2297 		/* really off slab. No need for manual alignment */
2298 		slab_size =
2299 		    cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
2300 
2301 #ifdef CONFIG_PAGE_POISONING
2302 		/* If we're going to use the generic kernel_map_pages()
2303 		 * poisoning, then it's going to smash the contents of
2304 		 * the redzone and userword anyhow, so switch them off.
2305 		 */
2306 		if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
2307 			flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2308 #endif
2309 	}
2310 
2311 	cachep->colour_off = cache_line_size();
2312 	/* Offset must be a multiple of the alignment. */
2313 	if (cachep->colour_off < align)
2314 		cachep->colour_off = align;
2315 	cachep->colour = left_over / cachep->colour_off;
2316 	cachep->slab_size = slab_size;
2317 	cachep->flags = flags;
2318 	cachep->gfpflags = 0;
2319 	if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
2320 		cachep->gfpflags |= GFP_DMA;
2321 	cachep->buffer_size = size;
2322 	cachep->reciprocal_buffer_size = reciprocal_value(size);
2323 
2324 	if (flags & CFLGS_OFF_SLAB) {
2325 		cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
2326 		/*
2327 		 * This is a possibility for one of the malloc_sizes caches.
2328 		 * But since we go off slab only for object size greater than
2329 		 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
2330 		 * this should not happen at all.
2331 		 * But leave a BUG_ON for some lucky dude.
2332 		 */
2333 		BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
2334 	}
2335 	cachep->ctor = ctor;
2336 	cachep->name = name;
2337 
2338 	if (setup_cpu_cache(cachep, gfp)) {
2339 		__kmem_cache_destroy(cachep);
2340 		cachep = NULL;
2341 		goto oops;
2342 	}
2343 
2344 	/* cache setup completed, link it into the list */
2345 	list_add(&cachep->next, &cache_chain);
2346 oops:
2347 	if (!cachep && (flags & SLAB_PANIC))
2348 		panic("kmem_cache_create(): failed to create slab `%s'\n",
2349 		      name);
2350 	if (slab_is_available()) {
2351 		mutex_unlock(&cache_chain_mutex);
2352 		put_online_cpus();
2353 	}
2354 	return cachep;
2355 }
2356 EXPORT_SYMBOL(kmem_cache_create);
2357 
2358 #if DEBUG
2359 static void check_irq_off(void)
2360 {
2361 	BUG_ON(!irqs_disabled());
2362 }
2363 
2364 static void check_irq_on(void)
2365 {
2366 	BUG_ON(irqs_disabled());
2367 }
2368 
2369 static void check_spinlock_acquired(struct kmem_cache *cachep)
2370 {
2371 #ifdef CONFIG_SMP
2372 	check_irq_off();
2373 	assert_spin_locked(&cachep->nodelists[numa_node_id()]->list_lock);
2374 #endif
2375 }
2376 
2377 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2378 {
2379 #ifdef CONFIG_SMP
2380 	check_irq_off();
2381 	assert_spin_locked(&cachep->nodelists[node]->list_lock);
2382 #endif
2383 }
2384 
2385 #else
2386 #define check_irq_off()	do { } while(0)
2387 #define check_irq_on()	do { } while(0)
2388 #define check_spinlock_acquired(x) do { } while(0)
2389 #define check_spinlock_acquired_node(x, y) do { } while(0)
2390 #endif
2391 
2392 static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
2393 			struct array_cache *ac,
2394 			int force, int node);
2395 
2396 static void do_drain(void *arg)
2397 {
2398 	struct kmem_cache *cachep = arg;
2399 	struct array_cache *ac;
2400 	int node = numa_node_id();
2401 
2402 	check_irq_off();
2403 	ac = cpu_cache_get(cachep);
2404 	spin_lock(&cachep->nodelists[node]->list_lock);
2405 	free_block(cachep, ac->entry, ac->avail, node);
2406 	spin_unlock(&cachep->nodelists[node]->list_lock);
2407 	ac->avail = 0;
2408 }
2409 
2410 static void drain_cpu_caches(struct kmem_cache *cachep)
2411 {
2412 	struct kmem_list3 *l3;
2413 	int node;
2414 
2415 	on_each_cpu(do_drain, cachep, 1);
2416 	check_irq_on();
2417 	for_each_online_node(node) {
2418 		l3 = cachep->nodelists[node];
2419 		if (l3 && l3->alien)
2420 			drain_alien_cache(cachep, l3->alien);
2421 	}
2422 
2423 	for_each_online_node(node) {
2424 		l3 = cachep->nodelists[node];
2425 		if (l3)
2426 			drain_array(cachep, l3, l3->shared, 1, node);
2427 	}
2428 }
2429 
2430 /*
2431  * Remove slabs from the list of free slabs.
2432  * Specify the number of slabs to drain in tofree.
2433  *
2434  * Returns the actual number of slabs released.
2435  */
2436 static int drain_freelist(struct kmem_cache *cache,
2437 			struct kmem_list3 *l3, int tofree)
2438 {
2439 	struct list_head *p;
2440 	int nr_freed;
2441 	struct slab *slabp;
2442 
2443 	nr_freed = 0;
2444 	while (nr_freed < tofree && !list_empty(&l3->slabs_free)) {
2445 
2446 		spin_lock_irq(&l3->list_lock);
2447 		p = l3->slabs_free.prev;
2448 		if (p == &l3->slabs_free) {
2449 			spin_unlock_irq(&l3->list_lock);
2450 			goto out;
2451 		}
2452 
2453 		slabp = list_entry(p, struct slab, list);
2454 #if DEBUG
2455 		BUG_ON(slabp->inuse);
2456 #endif
2457 		list_del(&slabp->list);
2458 		/*
2459 		 * Safe to drop the lock. The slab is no longer linked
2460 		 * to the cache.
2461 		 */
2462 		l3->free_objects -= cache->num;
2463 		spin_unlock_irq(&l3->list_lock);
2464 		slab_destroy(cache, slabp);
2465 		nr_freed++;
2466 	}
2467 out:
2468 	return nr_freed;
2469 }
2470 
2471 /* Called with cache_chain_mutex held to protect against cpu hotplug */
2472 static int __cache_shrink(struct kmem_cache *cachep)
2473 {
2474 	int ret = 0, i = 0;
2475 	struct kmem_list3 *l3;
2476 
2477 	drain_cpu_caches(cachep);
2478 
2479 	check_irq_on();
2480 	for_each_online_node(i) {
2481 		l3 = cachep->nodelists[i];
2482 		if (!l3)
2483 			continue;
2484 
2485 		drain_freelist(cachep, l3, l3->free_objects);
2486 
2487 		ret += !list_empty(&l3->slabs_full) ||
2488 			!list_empty(&l3->slabs_partial);
2489 	}
2490 	return (ret ? 1 : 0);
2491 }
2492 
2493 /**
2494  * kmem_cache_shrink - Shrink a cache.
2495  * @cachep: The cache to shrink.
2496  *
2497  * Releases as many slabs as possible for a cache.
2498  * To help debugging, a zero exit status indicates all slabs were released.
2499  */
2500 int kmem_cache_shrink(struct kmem_cache *cachep)
2501 {
2502 	int ret;
2503 	BUG_ON(!cachep || in_interrupt());
2504 
2505 	get_online_cpus();
2506 	mutex_lock(&cache_chain_mutex);
2507 	ret = __cache_shrink(cachep);
2508 	mutex_unlock(&cache_chain_mutex);
2509 	put_online_cpus();
2510 	return ret;
2511 }
2512 EXPORT_SYMBOL(kmem_cache_shrink);
2513 
2514 /**
2515  * kmem_cache_destroy - delete a cache
2516  * @cachep: the cache to destroy
2517  *
2518  * Remove a &struct kmem_cache object from the slab cache.
2519  *
2520  * It is expected this function will be called by a module when it is
2521  * unloaded.  This will remove the cache completely, and avoid a duplicate
2522  * cache being allocated each time a module is loaded and unloaded, if the
2523  * module doesn't have persistent in-kernel storage across loads and unloads.
2524  *
2525  * The cache must be empty before calling this function.
2526  *
2527  * The caller must guarantee that noone will allocate memory from the cache
2528  * during the kmem_cache_destroy().
2529  */
2530 void kmem_cache_destroy(struct kmem_cache *cachep)
2531 {
2532 	BUG_ON(!cachep || in_interrupt());
2533 
2534 	/* Find the cache in the chain of caches. */
2535 	get_online_cpus();
2536 	mutex_lock(&cache_chain_mutex);
2537 	/*
2538 	 * the chain is never empty, cache_cache is never destroyed
2539 	 */
2540 	list_del(&cachep->next);
2541 	if (__cache_shrink(cachep)) {
2542 		slab_error(cachep, "Can't free all objects");
2543 		list_add(&cachep->next, &cache_chain);
2544 		mutex_unlock(&cache_chain_mutex);
2545 		put_online_cpus();
2546 		return;
2547 	}
2548 
2549 	if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
2550 		rcu_barrier();
2551 
2552 	__kmem_cache_destroy(cachep);
2553 	mutex_unlock(&cache_chain_mutex);
2554 	put_online_cpus();
2555 }
2556 EXPORT_SYMBOL(kmem_cache_destroy);
2557 
2558 /*
2559  * Get the memory for a slab management obj.
2560  * For a slab cache when the slab descriptor is off-slab, slab descriptors
2561  * always come from malloc_sizes caches.  The slab descriptor cannot
2562  * come from the same cache which is getting created because,
2563  * when we are searching for an appropriate cache for these
2564  * descriptors in kmem_cache_create, we search through the malloc_sizes array.
2565  * If we are creating a malloc_sizes cache here it would not be visible to
2566  * kmem_find_general_cachep till the initialization is complete.
2567  * Hence we cannot have slabp_cache same as the original cache.
2568  */
2569 static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,
2570 				   int colour_off, gfp_t local_flags,
2571 				   int nodeid)
2572 {
2573 	struct slab *slabp;
2574 
2575 	if (OFF_SLAB(cachep)) {
2576 		/* Slab management obj is off-slab. */
2577 		slabp = kmem_cache_alloc_node(cachep->slabp_cache,
2578 					      local_flags, nodeid);
2579 		/*
2580 		 * If the first object in the slab is leaked (it's allocated
2581 		 * but no one has a reference to it), we want to make sure
2582 		 * kmemleak does not treat the ->s_mem pointer as a reference
2583 		 * to the object. Otherwise we will not report the leak.
2584 		 */
2585 		kmemleak_scan_area(slabp, offsetof(struct slab, list),
2586 				   sizeof(struct list_head), local_flags);
2587 		if (!slabp)
2588 			return NULL;
2589 	} else {
2590 		slabp = objp + colour_off;
2591 		colour_off += cachep->slab_size;
2592 	}
2593 	slabp->inuse = 0;
2594 	slabp->colouroff = colour_off;
2595 	slabp->s_mem = objp + colour_off;
2596 	slabp->nodeid = nodeid;
2597 	slabp->free = 0;
2598 	return slabp;
2599 }
2600 
2601 static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
2602 {
2603 	return (kmem_bufctl_t *) (slabp + 1);
2604 }
2605 
2606 static void cache_init_objs(struct kmem_cache *cachep,
2607 			    struct slab *slabp)
2608 {
2609 	int i;
2610 
2611 	for (i = 0; i < cachep->num; i++) {
2612 		void *objp = index_to_obj(cachep, slabp, i);
2613 #if DEBUG
2614 		/* need to poison the objs? */
2615 		if (cachep->flags & SLAB_POISON)
2616 			poison_obj(cachep, objp, POISON_FREE);
2617 		if (cachep->flags & SLAB_STORE_USER)
2618 			*dbg_userword(cachep, objp) = NULL;
2619 
2620 		if (cachep->flags & SLAB_RED_ZONE) {
2621 			*dbg_redzone1(cachep, objp) = RED_INACTIVE;
2622 			*dbg_redzone2(cachep, objp) = RED_INACTIVE;
2623 		}
2624 		/*
2625 		 * Constructors are not allowed to allocate memory from the same
2626 		 * cache which they are a constructor for.  Otherwise, deadlock.
2627 		 * They must also be threaded.
2628 		 */
2629 		if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2630 			cachep->ctor(objp + obj_offset(cachep));
2631 
2632 		if (cachep->flags & SLAB_RED_ZONE) {
2633 			if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2634 				slab_error(cachep, "constructor overwrote the"
2635 					   " end of an object");
2636 			if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2637 				slab_error(cachep, "constructor overwrote the"
2638 					   " start of an object");
2639 		}
2640 		if ((cachep->buffer_size % PAGE_SIZE) == 0 &&
2641 			    OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2642 			kernel_map_pages(virt_to_page(objp),
2643 					 cachep->buffer_size / PAGE_SIZE, 0);
2644 #else
2645 		if (cachep->ctor)
2646 			cachep->ctor(objp);
2647 #endif
2648 		slab_bufctl(slabp)[i] = i + 1;
2649 	}
2650 	slab_bufctl(slabp)[i - 1] = BUFCTL_END;
2651 }
2652 
2653 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2654 {
2655 	if (CONFIG_ZONE_DMA_FLAG) {
2656 		if (flags & GFP_DMA)
2657 			BUG_ON(!(cachep->gfpflags & GFP_DMA));
2658 		else
2659 			BUG_ON(cachep->gfpflags & GFP_DMA);
2660 	}
2661 }
2662 
2663 static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
2664 				int nodeid)
2665 {
2666 	void *objp = index_to_obj(cachep, slabp, slabp->free);
2667 	kmem_bufctl_t next;
2668 
2669 	slabp->inuse++;
2670 	next = slab_bufctl(slabp)[slabp->free];
2671 #if DEBUG
2672 	slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2673 	WARN_ON(slabp->nodeid != nodeid);
2674 #endif
2675 	slabp->free = next;
2676 
2677 	return objp;
2678 }
2679 
2680 static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
2681 				void *objp, int nodeid)
2682 {
2683 	unsigned int objnr = obj_to_index(cachep, slabp, objp);
2684 
2685 #if DEBUG
2686 	/* Verify that the slab belongs to the intended node */
2687 	WARN_ON(slabp->nodeid != nodeid);
2688 
2689 	if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
2690 		printk(KERN_ERR "slab: double free detected in cache "
2691 				"'%s', objp %p\n", cachep->name, objp);
2692 		BUG();
2693 	}
2694 #endif
2695 	slab_bufctl(slabp)[objnr] = slabp->free;
2696 	slabp->free = objnr;
2697 	slabp->inuse--;
2698 }
2699 
2700 /*
2701  * Map pages beginning at addr to the given cache and slab. This is required
2702  * for the slab allocator to be able to lookup the cache and slab of a
2703  * virtual address for kfree, ksize, kmem_ptr_validate, and slab debugging.
2704  */
2705 static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
2706 			   void *addr)
2707 {
2708 	int nr_pages;
2709 	struct page *page;
2710 
2711 	page = virt_to_page(addr);
2712 
2713 	nr_pages = 1;
2714 	if (likely(!PageCompound(page)))
2715 		nr_pages <<= cache->gfporder;
2716 
2717 	do {
2718 		page_set_cache(page, cache);
2719 		page_set_slab(page, slab);
2720 		page++;
2721 	} while (--nr_pages);
2722 }
2723 
2724 /*
2725  * Grow (by 1) the number of slabs within a cache.  This is called by
2726  * kmem_cache_alloc() when there are no active objs left in a cache.
2727  */
2728 static int cache_grow(struct kmem_cache *cachep,
2729 		gfp_t flags, int nodeid, void *objp)
2730 {
2731 	struct slab *slabp;
2732 	size_t offset;
2733 	gfp_t local_flags;
2734 	struct kmem_list3 *l3;
2735 
2736 	/*
2737 	 * Be lazy and only check for valid flags here,  keeping it out of the
2738 	 * critical path in kmem_cache_alloc().
2739 	 */
2740 	BUG_ON(flags & GFP_SLAB_BUG_MASK);
2741 	local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2742 
2743 	/* Take the l3 list lock to change the colour_next on this node */
2744 	check_irq_off();
2745 	l3 = cachep->nodelists[nodeid];
2746 	spin_lock(&l3->list_lock);
2747 
2748 	/* Get colour for the slab, and cal the next value. */
2749 	offset = l3->colour_next;
2750 	l3->colour_next++;
2751 	if (l3->colour_next >= cachep->colour)
2752 		l3->colour_next = 0;
2753 	spin_unlock(&l3->list_lock);
2754 
2755 	offset *= cachep->colour_off;
2756 
2757 	if (local_flags & __GFP_WAIT)
2758 		local_irq_enable();
2759 
2760 	/*
2761 	 * The test for missing atomic flag is performed here, rather than
2762 	 * the more obvious place, simply to reduce the critical path length
2763 	 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2764 	 * will eventually be caught here (where it matters).
2765 	 */
2766 	kmem_flagcheck(cachep, flags);
2767 
2768 	/*
2769 	 * Get mem for the objs.  Attempt to allocate a physical page from
2770 	 * 'nodeid'.
2771 	 */
2772 	if (!objp)
2773 		objp = kmem_getpages(cachep, local_flags, nodeid);
2774 	if (!objp)
2775 		goto failed;
2776 
2777 	/* Get slab management. */
2778 	slabp = alloc_slabmgmt(cachep, objp, offset,
2779 			local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
2780 	if (!slabp)
2781 		goto opps1;
2782 
2783 	slab_map_pages(cachep, slabp, objp);
2784 
2785 	cache_init_objs(cachep, slabp);
2786 
2787 	if (local_flags & __GFP_WAIT)
2788 		local_irq_disable();
2789 	check_irq_off();
2790 	spin_lock(&l3->list_lock);
2791 
2792 	/* Make slab active. */
2793 	list_add_tail(&slabp->list, &(l3->slabs_free));
2794 	STATS_INC_GROWN(cachep);
2795 	l3->free_objects += cachep->num;
2796 	spin_unlock(&l3->list_lock);
2797 	return 1;
2798 opps1:
2799 	kmem_freepages(cachep, objp);
2800 failed:
2801 	if (local_flags & __GFP_WAIT)
2802 		local_irq_disable();
2803 	return 0;
2804 }
2805 
2806 #if DEBUG
2807 
2808 /*
2809  * Perform extra freeing checks:
2810  * - detect bad pointers.
2811  * - POISON/RED_ZONE checking
2812  */
2813 static void kfree_debugcheck(const void *objp)
2814 {
2815 	if (!virt_addr_valid(objp)) {
2816 		printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2817 		       (unsigned long)objp);
2818 		BUG();
2819 	}
2820 }
2821 
2822 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2823 {
2824 	unsigned long long redzone1, redzone2;
2825 
2826 	redzone1 = *dbg_redzone1(cache, obj);
2827 	redzone2 = *dbg_redzone2(cache, obj);
2828 
2829 	/*
2830 	 * Redzone is ok.
2831 	 */
2832 	if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2833 		return;
2834 
2835 	if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2836 		slab_error(cache, "double free detected");
2837 	else
2838 		slab_error(cache, "memory outside object was overwritten");
2839 
2840 	printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
2841 			obj, redzone1, redzone2);
2842 }
2843 
2844 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2845 				   void *caller)
2846 {
2847 	struct page *page;
2848 	unsigned int objnr;
2849 	struct slab *slabp;
2850 
2851 	BUG_ON(virt_to_cache(objp) != cachep);
2852 
2853 	objp -= obj_offset(cachep);
2854 	kfree_debugcheck(objp);
2855 	page = virt_to_head_page(objp);
2856 
2857 	slabp = page_get_slab(page);
2858 
2859 	if (cachep->flags & SLAB_RED_ZONE) {
2860 		verify_redzone_free(cachep, objp);
2861 		*dbg_redzone1(cachep, objp) = RED_INACTIVE;
2862 		*dbg_redzone2(cachep, objp) = RED_INACTIVE;
2863 	}
2864 	if (cachep->flags & SLAB_STORE_USER)
2865 		*dbg_userword(cachep, objp) = caller;
2866 
2867 	objnr = obj_to_index(cachep, slabp, objp);
2868 
2869 	BUG_ON(objnr >= cachep->num);
2870 	BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
2871 
2872 #ifdef CONFIG_DEBUG_SLAB_LEAK
2873 	slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
2874 #endif
2875 	if (cachep->flags & SLAB_POISON) {
2876 #ifdef CONFIG_DEBUG_PAGEALLOC
2877 		if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2878 			store_stackinfo(cachep, objp, (unsigned long)caller);
2879 			kernel_map_pages(virt_to_page(objp),
2880 					 cachep->buffer_size / PAGE_SIZE, 0);
2881 		} else {
2882 			poison_obj(cachep, objp, POISON_FREE);
2883 		}
2884 #else
2885 		poison_obj(cachep, objp, POISON_FREE);
2886 #endif
2887 	}
2888 	return objp;
2889 }
2890 
2891 static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
2892 {
2893 	kmem_bufctl_t i;
2894 	int entries = 0;
2895 
2896 	/* Check slab's freelist to see if this obj is there. */
2897 	for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
2898 		entries++;
2899 		if (entries > cachep->num || i >= cachep->num)
2900 			goto bad;
2901 	}
2902 	if (entries != cachep->num - slabp->inuse) {
2903 bad:
2904 		printk(KERN_ERR "slab: Internal list corruption detected in "
2905 				"cache '%s'(%d), slabp %p(%d). Hexdump:\n",
2906 			cachep->name, cachep->num, slabp, slabp->inuse);
2907 		for (i = 0;
2908 		     i < sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t);
2909 		     i++) {
2910 			if (i % 16 == 0)
2911 				printk("\n%03x:", i);
2912 			printk(" %02x", ((unsigned char *)slabp)[i]);
2913 		}
2914 		printk("\n");
2915 		BUG();
2916 	}
2917 }
2918 #else
2919 #define kfree_debugcheck(x) do { } while(0)
2920 #define cache_free_debugcheck(x,objp,z) (objp)
2921 #define check_slabp(x,y) do { } while(0)
2922 #endif
2923 
2924 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
2925 {
2926 	int batchcount;
2927 	struct kmem_list3 *l3;
2928 	struct array_cache *ac;
2929 	int node;
2930 
2931 retry:
2932 	check_irq_off();
2933 	node = numa_node_id();
2934 	ac = cpu_cache_get(cachep);
2935 	batchcount = ac->batchcount;
2936 	if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2937 		/*
2938 		 * If there was little recent activity on this cache, then
2939 		 * perform only a partial refill.  Otherwise we could generate
2940 		 * refill bouncing.
2941 		 */
2942 		batchcount = BATCHREFILL_LIMIT;
2943 	}
2944 	l3 = cachep->nodelists[node];
2945 
2946 	BUG_ON(ac->avail > 0 || !l3);
2947 	spin_lock(&l3->list_lock);
2948 
2949 	/* See if we can refill from the shared array */
2950 	if (l3->shared && transfer_objects(ac, l3->shared, batchcount))
2951 		goto alloc_done;
2952 
2953 	while (batchcount > 0) {
2954 		struct list_head *entry;
2955 		struct slab *slabp;
2956 		/* Get slab alloc is to come from. */
2957 		entry = l3->slabs_partial.next;
2958 		if (entry == &l3->slabs_partial) {
2959 			l3->free_touched = 1;
2960 			entry = l3->slabs_free.next;
2961 			if (entry == &l3->slabs_free)
2962 				goto must_grow;
2963 		}
2964 
2965 		slabp = list_entry(entry, struct slab, list);
2966 		check_slabp(cachep, slabp);
2967 		check_spinlock_acquired(cachep);
2968 
2969 		/*
2970 		 * The slab was either on partial or free list so
2971 		 * there must be at least one object available for
2972 		 * allocation.
2973 		 */
2974 		BUG_ON(slabp->inuse >= cachep->num);
2975 
2976 		while (slabp->inuse < cachep->num && batchcount--) {
2977 			STATS_INC_ALLOCED(cachep);
2978 			STATS_INC_ACTIVE(cachep);
2979 			STATS_SET_HIGH(cachep);
2980 
2981 			ac->entry[ac->avail++] = slab_get_obj(cachep, slabp,
2982 							    node);
2983 		}
2984 		check_slabp(cachep, slabp);
2985 
2986 		/* move slabp to correct slabp list: */
2987 		list_del(&slabp->list);
2988 		if (slabp->free == BUFCTL_END)
2989 			list_add(&slabp->list, &l3->slabs_full);
2990 		else
2991 			list_add(&slabp->list, &l3->slabs_partial);
2992 	}
2993 
2994 must_grow:
2995 	l3->free_objects -= ac->avail;
2996 alloc_done:
2997 	spin_unlock(&l3->list_lock);
2998 
2999 	if (unlikely(!ac->avail)) {
3000 		int x;
3001 		x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
3002 
3003 		/* cache_grow can reenable interrupts, then ac could change. */
3004 		ac = cpu_cache_get(cachep);
3005 		if (!x && ac->avail == 0)	/* no objects in sight? abort */
3006 			return NULL;
3007 
3008 		if (!ac->avail)		/* objects refilled by interrupt? */
3009 			goto retry;
3010 	}
3011 	ac->touched = 1;
3012 	return ac->entry[--ac->avail];
3013 }
3014 
3015 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
3016 						gfp_t flags)
3017 {
3018 	might_sleep_if(flags & __GFP_WAIT);
3019 #if DEBUG
3020 	kmem_flagcheck(cachep, flags);
3021 #endif
3022 }
3023 
3024 #if DEBUG
3025 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
3026 				gfp_t flags, void *objp, void *caller)
3027 {
3028 	if (!objp)
3029 		return objp;
3030 	if (cachep->flags & SLAB_POISON) {
3031 #ifdef CONFIG_DEBUG_PAGEALLOC
3032 		if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
3033 			kernel_map_pages(virt_to_page(objp),
3034 					 cachep->buffer_size / PAGE_SIZE, 1);
3035 		else
3036 			check_poison_obj(cachep, objp);
3037 #else
3038 		check_poison_obj(cachep, objp);
3039 #endif
3040 		poison_obj(cachep, objp, POISON_INUSE);
3041 	}
3042 	if (cachep->flags & SLAB_STORE_USER)
3043 		*dbg_userword(cachep, objp) = caller;
3044 
3045 	if (cachep->flags & SLAB_RED_ZONE) {
3046 		if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
3047 				*dbg_redzone2(cachep, objp) != RED_INACTIVE) {
3048 			slab_error(cachep, "double free, or memory outside"
3049 						" object was overwritten");
3050 			printk(KERN_ERR
3051 				"%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3052 				objp, *dbg_redzone1(cachep, objp),
3053 				*dbg_redzone2(cachep, objp));
3054 		}
3055 		*dbg_redzone1(cachep, objp) = RED_ACTIVE;
3056 		*dbg_redzone2(cachep, objp) = RED_ACTIVE;
3057 	}
3058 #ifdef CONFIG_DEBUG_SLAB_LEAK
3059 	{
3060 		struct slab *slabp;
3061 		unsigned objnr;
3062 
3063 		slabp = page_get_slab(virt_to_head_page(objp));
3064 		objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size;
3065 		slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
3066 	}
3067 #endif
3068 	objp += obj_offset(cachep);
3069 	if (cachep->ctor && cachep->flags & SLAB_POISON)
3070 		cachep->ctor(objp);
3071 #if ARCH_SLAB_MINALIGN
3072 	if ((u32)objp & (ARCH_SLAB_MINALIGN-1)) {
3073 		printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3074 		       objp, ARCH_SLAB_MINALIGN);
3075 	}
3076 #endif
3077 	return objp;
3078 }
3079 #else
3080 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3081 #endif
3082 
3083 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
3084 {
3085 	if (cachep == &cache_cache)
3086 		return false;
3087 
3088 	return should_failslab(obj_size(cachep), flags);
3089 }
3090 
3091 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3092 {
3093 	void *objp;
3094 	struct array_cache *ac;
3095 
3096 	check_irq_off();
3097 
3098 	ac = cpu_cache_get(cachep);
3099 	if (likely(ac->avail)) {
3100 		STATS_INC_ALLOCHIT(cachep);
3101 		ac->touched = 1;
3102 		objp = ac->entry[--ac->avail];
3103 	} else {
3104 		STATS_INC_ALLOCMISS(cachep);
3105 		objp = cache_alloc_refill(cachep, flags);
3106 	}
3107 	/*
3108 	 * To avoid a false negative, if an object that is in one of the
3109 	 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3110 	 * treat the array pointers as a reference to the object.
3111 	 */
3112 	kmemleak_erase(&ac->entry[ac->avail]);
3113 	return objp;
3114 }
3115 
3116 #ifdef CONFIG_NUMA
3117 /*
3118  * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
3119  *
3120  * If we are in_interrupt, then process context, including cpusets and
3121  * mempolicy, may not apply and should not be used for allocation policy.
3122  */
3123 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3124 {
3125 	int nid_alloc, nid_here;
3126 
3127 	if (in_interrupt() || (flags & __GFP_THISNODE))
3128 		return NULL;
3129 	nid_alloc = nid_here = numa_node_id();
3130 	if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3131 		nid_alloc = cpuset_mem_spread_node();
3132 	else if (current->mempolicy)
3133 		nid_alloc = slab_node(current->mempolicy);
3134 	if (nid_alloc != nid_here)
3135 		return ____cache_alloc_node(cachep, flags, nid_alloc);
3136 	return NULL;
3137 }
3138 
3139 /*
3140  * Fallback function if there was no memory available and no objects on a
3141  * certain node and fall back is permitted. First we scan all the
3142  * available nodelists for available objects. If that fails then we
3143  * perform an allocation without specifying a node. This allows the page
3144  * allocator to do its reclaim / fallback magic. We then insert the
3145  * slab into the proper nodelist and then allocate from it.
3146  */
3147 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3148 {
3149 	struct zonelist *zonelist;
3150 	gfp_t local_flags;
3151 	struct zoneref *z;
3152 	struct zone *zone;
3153 	enum zone_type high_zoneidx = gfp_zone(flags);
3154 	void *obj = NULL;
3155 	int nid;
3156 
3157 	if (flags & __GFP_THISNODE)
3158 		return NULL;
3159 
3160 	zonelist = node_zonelist(slab_node(current->mempolicy), flags);
3161 	local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
3162 
3163 retry:
3164 	/*
3165 	 * Look through allowed nodes for objects available
3166 	 * from existing per node queues.
3167 	 */
3168 	for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3169 		nid = zone_to_nid(zone);
3170 
3171 		if (cpuset_zone_allowed_hardwall(zone, flags) &&
3172 			cache->nodelists[nid] &&
3173 			cache->nodelists[nid]->free_objects) {
3174 				obj = ____cache_alloc_node(cache,
3175 					flags | GFP_THISNODE, nid);
3176 				if (obj)
3177 					break;
3178 		}
3179 	}
3180 
3181 	if (!obj) {
3182 		/*
3183 		 * This allocation will be performed within the constraints
3184 		 * of the current cpuset / memory policy requirements.
3185 		 * We may trigger various forms of reclaim on the allowed
3186 		 * set and go into memory reserves if necessary.
3187 		 */
3188 		if (local_flags & __GFP_WAIT)
3189 			local_irq_enable();
3190 		kmem_flagcheck(cache, flags);
3191 		obj = kmem_getpages(cache, local_flags, numa_node_id());
3192 		if (local_flags & __GFP_WAIT)
3193 			local_irq_disable();
3194 		if (obj) {
3195 			/*
3196 			 * Insert into the appropriate per node queues
3197 			 */
3198 			nid = page_to_nid(virt_to_page(obj));
3199 			if (cache_grow(cache, flags, nid, obj)) {
3200 				obj = ____cache_alloc_node(cache,
3201 					flags | GFP_THISNODE, nid);
3202 				if (!obj)
3203 					/*
3204 					 * Another processor may allocate the
3205 					 * objects in the slab since we are
3206 					 * not holding any locks.
3207 					 */
3208 					goto retry;
3209 			} else {
3210 				/* cache_grow already freed obj */
3211 				obj = NULL;
3212 			}
3213 		}
3214 	}
3215 	return obj;
3216 }
3217 
3218 /*
3219  * A interface to enable slab creation on nodeid
3220  */
3221 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3222 				int nodeid)
3223 {
3224 	struct list_head *entry;
3225 	struct slab *slabp;
3226 	struct kmem_list3 *l3;
3227 	void *obj;
3228 	int x;
3229 
3230 	l3 = cachep->nodelists[nodeid];
3231 	BUG_ON(!l3);
3232 
3233 retry:
3234 	check_irq_off();
3235 	spin_lock(&l3->list_lock);
3236 	entry = l3->slabs_partial.next;
3237 	if (entry == &l3->slabs_partial) {
3238 		l3->free_touched = 1;
3239 		entry = l3->slabs_free.next;
3240 		if (entry == &l3->slabs_free)
3241 			goto must_grow;
3242 	}
3243 
3244 	slabp = list_entry(entry, struct slab, list);
3245 	check_spinlock_acquired_node(cachep, nodeid);
3246 	check_slabp(cachep, slabp);
3247 
3248 	STATS_INC_NODEALLOCS(cachep);
3249 	STATS_INC_ACTIVE(cachep);
3250 	STATS_SET_HIGH(cachep);
3251 
3252 	BUG_ON(slabp->inuse == cachep->num);
3253 
3254 	obj = slab_get_obj(cachep, slabp, nodeid);
3255 	check_slabp(cachep, slabp);
3256 	l3->free_objects--;
3257 	/* move slabp to correct slabp list: */
3258 	list_del(&slabp->list);
3259 
3260 	if (slabp->free == BUFCTL_END)
3261 		list_add(&slabp->list, &l3->slabs_full);
3262 	else
3263 		list_add(&slabp->list, &l3->slabs_partial);
3264 
3265 	spin_unlock(&l3->list_lock);
3266 	goto done;
3267 
3268 must_grow:
3269 	spin_unlock(&l3->list_lock);
3270 	x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
3271 	if (x)
3272 		goto retry;
3273 
3274 	return fallback_alloc(cachep, flags);
3275 
3276 done:
3277 	return obj;
3278 }
3279 
3280 /**
3281  * kmem_cache_alloc_node - Allocate an object on the specified node
3282  * @cachep: The cache to allocate from.
3283  * @flags: See kmalloc().
3284  * @nodeid: node number of the target node.
3285  * @caller: return address of caller, used for debug information
3286  *
3287  * Identical to kmem_cache_alloc but it will allocate memory on the given
3288  * node, which can improve the performance for cpu bound structures.
3289  *
3290  * Fallback to other node is possible if __GFP_THISNODE is not set.
3291  */
3292 static __always_inline void *
3293 __cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3294 		   void *caller)
3295 {
3296 	unsigned long save_flags;
3297 	void *ptr;
3298 
3299 	flags &= gfp_allowed_mask;
3300 
3301 	lockdep_trace_alloc(flags);
3302 
3303 	if (slab_should_failslab(cachep, flags))
3304 		return NULL;
3305 
3306 	cache_alloc_debugcheck_before(cachep, flags);
3307 	local_irq_save(save_flags);
3308 
3309 	if (unlikely(nodeid == -1))
3310 		nodeid = numa_node_id();
3311 
3312 	if (unlikely(!cachep->nodelists[nodeid])) {
3313 		/* Node not bootstrapped yet */
3314 		ptr = fallback_alloc(cachep, flags);
3315 		goto out;
3316 	}
3317 
3318 	if (nodeid == numa_node_id()) {
3319 		/*
3320 		 * Use the locally cached objects if possible.
3321 		 * However ____cache_alloc does not allow fallback
3322 		 * to other nodes. It may fail while we still have
3323 		 * objects on other nodes available.
3324 		 */
3325 		ptr = ____cache_alloc(cachep, flags);
3326 		if (ptr)
3327 			goto out;
3328 	}
3329 	/* ___cache_alloc_node can fall back to other nodes */
3330 	ptr = ____cache_alloc_node(cachep, flags, nodeid);
3331   out:
3332 	local_irq_restore(save_flags);
3333 	ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3334 	kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags,
3335 				 flags);
3336 
3337 	if (likely(ptr))
3338 		kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep));
3339 
3340 	if (unlikely((flags & __GFP_ZERO) && ptr))
3341 		memset(ptr, 0, obj_size(cachep));
3342 
3343 	return ptr;
3344 }
3345 
3346 static __always_inline void *
3347 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3348 {
3349 	void *objp;
3350 
3351 	if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
3352 		objp = alternate_node_alloc(cache, flags);
3353 		if (objp)
3354 			goto out;
3355 	}
3356 	objp = ____cache_alloc(cache, flags);
3357 
3358 	/*
3359 	 * We may just have run out of memory on the local node.
3360 	 * ____cache_alloc_node() knows how to locate memory on other nodes
3361 	 */
3362  	if (!objp)
3363  		objp = ____cache_alloc_node(cache, flags, numa_node_id());
3364 
3365   out:
3366 	return objp;
3367 }
3368 #else
3369 
3370 static __always_inline void *
3371 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3372 {
3373 	return ____cache_alloc(cachep, flags);
3374 }
3375 
3376 #endif /* CONFIG_NUMA */
3377 
3378 static __always_inline void *
3379 __cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller)
3380 {
3381 	unsigned long save_flags;
3382 	void *objp;
3383 
3384 	flags &= gfp_allowed_mask;
3385 
3386 	lockdep_trace_alloc(flags);
3387 
3388 	if (slab_should_failslab(cachep, flags))
3389 		return NULL;
3390 
3391 	cache_alloc_debugcheck_before(cachep, flags);
3392 	local_irq_save(save_flags);
3393 	objp = __do_cache_alloc(cachep, flags);
3394 	local_irq_restore(save_flags);
3395 	objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3396 	kmemleak_alloc_recursive(objp, obj_size(cachep), 1, cachep->flags,
3397 				 flags);
3398 	prefetchw(objp);
3399 
3400 	if (likely(objp))
3401 		kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep));
3402 
3403 	if (unlikely((flags & __GFP_ZERO) && objp))
3404 		memset(objp, 0, obj_size(cachep));
3405 
3406 	return objp;
3407 }
3408 
3409 /*
3410  * Caller needs to acquire correct kmem_list's list_lock
3411  */
3412 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
3413 		       int node)
3414 {
3415 	int i;
3416 	struct kmem_list3 *l3;
3417 
3418 	for (i = 0; i < nr_objects; i++) {
3419 		void *objp = objpp[i];
3420 		struct slab *slabp;
3421 
3422 		slabp = virt_to_slab(objp);
3423 		l3 = cachep->nodelists[node];
3424 		list_del(&slabp->list);
3425 		check_spinlock_acquired_node(cachep, node);
3426 		check_slabp(cachep, slabp);
3427 		slab_put_obj(cachep, slabp, objp, node);
3428 		STATS_DEC_ACTIVE(cachep);
3429 		l3->free_objects++;
3430 		check_slabp(cachep, slabp);
3431 
3432 		/* fixup slab chains */
3433 		if (slabp->inuse == 0) {
3434 			if (l3->free_objects > l3->free_limit) {
3435 				l3->free_objects -= cachep->num;
3436 				/* No need to drop any previously held
3437 				 * lock here, even if we have a off-slab slab
3438 				 * descriptor it is guaranteed to come from
3439 				 * a different cache, refer to comments before
3440 				 * alloc_slabmgmt.
3441 				 */
3442 				slab_destroy(cachep, slabp);
3443 			} else {
3444 				list_add(&slabp->list, &l3->slabs_free);
3445 			}
3446 		} else {
3447 			/* Unconditionally move a slab to the end of the
3448 			 * partial list on free - maximum time for the
3449 			 * other objects to be freed, too.
3450 			 */
3451 			list_add_tail(&slabp->list, &l3->slabs_partial);
3452 		}
3453 	}
3454 }
3455 
3456 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3457 {
3458 	int batchcount;
3459 	struct kmem_list3 *l3;
3460 	int node = numa_node_id();
3461 
3462 	batchcount = ac->batchcount;
3463 #if DEBUG
3464 	BUG_ON(!batchcount || batchcount > ac->avail);
3465 #endif
3466 	check_irq_off();
3467 	l3 = cachep->nodelists[node];
3468 	spin_lock(&l3->list_lock);
3469 	if (l3->shared) {
3470 		struct array_cache *shared_array = l3->shared;
3471 		int max = shared_array->limit - shared_array->avail;
3472 		if (max) {
3473 			if (batchcount > max)
3474 				batchcount = max;
3475 			memcpy(&(shared_array->entry[shared_array->avail]),
3476 			       ac->entry, sizeof(void *) * batchcount);
3477 			shared_array->avail += batchcount;
3478 			goto free_done;
3479 		}
3480 	}
3481 
3482 	free_block(cachep, ac->entry, batchcount, node);
3483 free_done:
3484 #if STATS
3485 	{
3486 		int i = 0;
3487 		struct list_head *p;
3488 
3489 		p = l3->slabs_free.next;
3490 		while (p != &(l3->slabs_free)) {
3491 			struct slab *slabp;
3492 
3493 			slabp = list_entry(p, struct slab, list);
3494 			BUG_ON(slabp->inuse);
3495 
3496 			i++;
3497 			p = p->next;
3498 		}
3499 		STATS_SET_FREEABLE(cachep, i);
3500 	}
3501 #endif
3502 	spin_unlock(&l3->list_lock);
3503 	ac->avail -= batchcount;
3504 	memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3505 }
3506 
3507 /*
3508  * Release an obj back to its cache. If the obj has a constructed state, it must
3509  * be in this state _before_ it is released.  Called with disabled ints.
3510  */
3511 static inline void __cache_free(struct kmem_cache *cachep, void *objp)
3512 {
3513 	struct array_cache *ac = cpu_cache_get(cachep);
3514 
3515 	check_irq_off();
3516 	kmemleak_free_recursive(objp, cachep->flags);
3517 	objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
3518 
3519 	kmemcheck_slab_free(cachep, objp, obj_size(cachep));
3520 
3521 	/*
3522 	 * Skip calling cache_free_alien() when the platform is not numa.
3523 	 * This will avoid cache misses that happen while accessing slabp (which
3524 	 * is per page memory  reference) to get nodeid. Instead use a global
3525 	 * variable to skip the call, which is mostly likely to be present in
3526 	 * the cache.
3527 	 */
3528 	if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3529 		return;
3530 
3531 	if (likely(ac->avail < ac->limit)) {
3532 		STATS_INC_FREEHIT(cachep);
3533 		ac->entry[ac->avail++] = objp;
3534 		return;
3535 	} else {
3536 		STATS_INC_FREEMISS(cachep);
3537 		cache_flusharray(cachep, ac);
3538 		ac->entry[ac->avail++] = objp;
3539 	}
3540 }
3541 
3542 /**
3543  * kmem_cache_alloc - Allocate an object
3544  * @cachep: The cache to allocate from.
3545  * @flags: See kmalloc().
3546  *
3547  * Allocate an object from this cache.  The flags are only relevant
3548  * if the cache has no available objects.
3549  */
3550 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3551 {
3552 	void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
3553 
3554 	trace_kmem_cache_alloc(_RET_IP_, ret,
3555 			       obj_size(cachep), cachep->buffer_size, flags);
3556 
3557 	return ret;
3558 }
3559 EXPORT_SYMBOL(kmem_cache_alloc);
3560 
3561 #ifdef CONFIG_KMEMTRACE
3562 void *kmem_cache_alloc_notrace(struct kmem_cache *cachep, gfp_t flags)
3563 {
3564 	return __cache_alloc(cachep, flags, __builtin_return_address(0));
3565 }
3566 EXPORT_SYMBOL(kmem_cache_alloc_notrace);
3567 #endif
3568 
3569 /**
3570  * kmem_ptr_validate - check if an untrusted pointer might be a slab entry.
3571  * @cachep: the cache we're checking against
3572  * @ptr: pointer to validate
3573  *
3574  * This verifies that the untrusted pointer looks sane;
3575  * it is _not_ a guarantee that the pointer is actually
3576  * part of the slab cache in question, but it at least
3577  * validates that the pointer can be dereferenced and
3578  * looks half-way sane.
3579  *
3580  * Currently only used for dentry validation.
3581  */
3582 int kmem_ptr_validate(struct kmem_cache *cachep, const void *ptr)
3583 {
3584 	unsigned long addr = (unsigned long)ptr;
3585 	unsigned long min_addr = PAGE_OFFSET;
3586 	unsigned long align_mask = BYTES_PER_WORD - 1;
3587 	unsigned long size = cachep->buffer_size;
3588 	struct page *page;
3589 
3590 	if (unlikely(addr < min_addr))
3591 		goto out;
3592 	if (unlikely(addr > (unsigned long)high_memory - size))
3593 		goto out;
3594 	if (unlikely(addr & align_mask))
3595 		goto out;
3596 	if (unlikely(!kern_addr_valid(addr)))
3597 		goto out;
3598 	if (unlikely(!kern_addr_valid(addr + size - 1)))
3599 		goto out;
3600 	page = virt_to_page(ptr);
3601 	if (unlikely(!PageSlab(page)))
3602 		goto out;
3603 	if (unlikely(page_get_cache(page) != cachep))
3604 		goto out;
3605 	return 1;
3606 out:
3607 	return 0;
3608 }
3609 
3610 #ifdef CONFIG_NUMA
3611 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3612 {
3613 	void *ret = __cache_alloc_node(cachep, flags, nodeid,
3614 				       __builtin_return_address(0));
3615 
3616 	trace_kmem_cache_alloc_node(_RET_IP_, ret,
3617 				    obj_size(cachep), cachep->buffer_size,
3618 				    flags, nodeid);
3619 
3620 	return ret;
3621 }
3622 EXPORT_SYMBOL(kmem_cache_alloc_node);
3623 
3624 #ifdef CONFIG_KMEMTRACE
3625 void *kmem_cache_alloc_node_notrace(struct kmem_cache *cachep,
3626 				    gfp_t flags,
3627 				    int nodeid)
3628 {
3629 	return __cache_alloc_node(cachep, flags, nodeid,
3630 				  __builtin_return_address(0));
3631 }
3632 EXPORT_SYMBOL(kmem_cache_alloc_node_notrace);
3633 #endif
3634 
3635 static __always_inline void *
3636 __do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller)
3637 {
3638 	struct kmem_cache *cachep;
3639 	void *ret;
3640 
3641 	cachep = kmem_find_general_cachep(size, flags);
3642 	if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3643 		return cachep;
3644 	ret = kmem_cache_alloc_node_notrace(cachep, flags, node);
3645 
3646 	trace_kmalloc_node((unsigned long) caller, ret,
3647 			   size, cachep->buffer_size, flags, node);
3648 
3649 	return ret;
3650 }
3651 
3652 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_KMEMTRACE)
3653 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3654 {
3655 	return __do_kmalloc_node(size, flags, node,
3656 			__builtin_return_address(0));
3657 }
3658 EXPORT_SYMBOL(__kmalloc_node);
3659 
3660 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3661 		int node, unsigned long caller)
3662 {
3663 	return __do_kmalloc_node(size, flags, node, (void *)caller);
3664 }
3665 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3666 #else
3667 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3668 {
3669 	return __do_kmalloc_node(size, flags, node, NULL);
3670 }
3671 EXPORT_SYMBOL(__kmalloc_node);
3672 #endif /* CONFIG_DEBUG_SLAB */
3673 #endif /* CONFIG_NUMA */
3674 
3675 /**
3676  * __do_kmalloc - allocate memory
3677  * @size: how many bytes of memory are required.
3678  * @flags: the type of memory to allocate (see kmalloc).
3679  * @caller: function caller for debug tracking of the caller
3680  */
3681 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3682 					  void *caller)
3683 {
3684 	struct kmem_cache *cachep;
3685 	void *ret;
3686 
3687 	/* If you want to save a few bytes .text space: replace
3688 	 * __ with kmem_.
3689 	 * Then kmalloc uses the uninlined functions instead of the inline
3690 	 * functions.
3691 	 */
3692 	cachep = __find_general_cachep(size, flags);
3693 	if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3694 		return cachep;
3695 	ret = __cache_alloc(cachep, flags, caller);
3696 
3697 	trace_kmalloc((unsigned long) caller, ret,
3698 		      size, cachep->buffer_size, flags);
3699 
3700 	return ret;
3701 }
3702 
3703 
3704 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_KMEMTRACE)
3705 void *__kmalloc(size_t size, gfp_t flags)
3706 {
3707 	return __do_kmalloc(size, flags, __builtin_return_address(0));
3708 }
3709 EXPORT_SYMBOL(__kmalloc);
3710 
3711 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3712 {
3713 	return __do_kmalloc(size, flags, (void *)caller);
3714 }
3715 EXPORT_SYMBOL(__kmalloc_track_caller);
3716 
3717 #else
3718 void *__kmalloc(size_t size, gfp_t flags)
3719 {
3720 	return __do_kmalloc(size, flags, NULL);
3721 }
3722 EXPORT_SYMBOL(__kmalloc);
3723 #endif
3724 
3725 /**
3726  * kmem_cache_free - Deallocate an object
3727  * @cachep: The cache the allocation was from.
3728  * @objp: The previously allocated object.
3729  *
3730  * Free an object which was previously allocated from this
3731  * cache.
3732  */
3733 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3734 {
3735 	unsigned long flags;
3736 
3737 	local_irq_save(flags);
3738 	debug_check_no_locks_freed(objp, obj_size(cachep));
3739 	if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3740 		debug_check_no_obj_freed(objp, obj_size(cachep));
3741 	__cache_free(cachep, objp);
3742 	local_irq_restore(flags);
3743 
3744 	trace_kmem_cache_free(_RET_IP_, objp);
3745 }
3746 EXPORT_SYMBOL(kmem_cache_free);
3747 
3748 /**
3749  * kfree - free previously allocated memory
3750  * @objp: pointer returned by kmalloc.
3751  *
3752  * If @objp is NULL, no operation is performed.
3753  *
3754  * Don't free memory not originally allocated by kmalloc()
3755  * or you will run into trouble.
3756  */
3757 void kfree(const void *objp)
3758 {
3759 	struct kmem_cache *c;
3760 	unsigned long flags;
3761 
3762 	trace_kfree(_RET_IP_, objp);
3763 
3764 	if (unlikely(ZERO_OR_NULL_PTR(objp)))
3765 		return;
3766 	local_irq_save(flags);
3767 	kfree_debugcheck(objp);
3768 	c = virt_to_cache(objp);
3769 	debug_check_no_locks_freed(objp, obj_size(c));
3770 	debug_check_no_obj_freed(objp, obj_size(c));
3771 	__cache_free(c, (void *)objp);
3772 	local_irq_restore(flags);
3773 }
3774 EXPORT_SYMBOL(kfree);
3775 
3776 unsigned int kmem_cache_size(struct kmem_cache *cachep)
3777 {
3778 	return obj_size(cachep);
3779 }
3780 EXPORT_SYMBOL(kmem_cache_size);
3781 
3782 const char *kmem_cache_name(struct kmem_cache *cachep)
3783 {
3784 	return cachep->name;
3785 }
3786 EXPORT_SYMBOL_GPL(kmem_cache_name);
3787 
3788 /*
3789  * This initializes kmem_list3 or resizes various caches for all nodes.
3790  */
3791 static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
3792 {
3793 	int node;
3794 	struct kmem_list3 *l3;
3795 	struct array_cache *new_shared;
3796 	struct array_cache **new_alien = NULL;
3797 
3798 	for_each_online_node(node) {
3799 
3800                 if (use_alien_caches) {
3801                         new_alien = alloc_alien_cache(node, cachep->limit, gfp);
3802                         if (!new_alien)
3803                                 goto fail;
3804                 }
3805 
3806 		new_shared = NULL;
3807 		if (cachep->shared) {
3808 			new_shared = alloc_arraycache(node,
3809 				cachep->shared*cachep->batchcount,
3810 					0xbaadf00d, gfp);
3811 			if (!new_shared) {
3812 				free_alien_cache(new_alien);
3813 				goto fail;
3814 			}
3815 		}
3816 
3817 		l3 = cachep->nodelists[node];
3818 		if (l3) {
3819 			struct array_cache *shared = l3->shared;
3820 
3821 			spin_lock_irq(&l3->list_lock);
3822 
3823 			if (shared)
3824 				free_block(cachep, shared->entry,
3825 						shared->avail, node);
3826 
3827 			l3->shared = new_shared;
3828 			if (!l3->alien) {
3829 				l3->alien = new_alien;
3830 				new_alien = NULL;
3831 			}
3832 			l3->free_limit = (1 + nr_cpus_node(node)) *
3833 					cachep->batchcount + cachep->num;
3834 			spin_unlock_irq(&l3->list_lock);
3835 			kfree(shared);
3836 			free_alien_cache(new_alien);
3837 			continue;
3838 		}
3839 		l3 = kmalloc_node(sizeof(struct kmem_list3), gfp, node);
3840 		if (!l3) {
3841 			free_alien_cache(new_alien);
3842 			kfree(new_shared);
3843 			goto fail;
3844 		}
3845 
3846 		kmem_list3_init(l3);
3847 		l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
3848 				((unsigned long)cachep) % REAPTIMEOUT_LIST3;
3849 		l3->shared = new_shared;
3850 		l3->alien = new_alien;
3851 		l3->free_limit = (1 + nr_cpus_node(node)) *
3852 					cachep->batchcount + cachep->num;
3853 		cachep->nodelists[node] = l3;
3854 	}
3855 	return 0;
3856 
3857 fail:
3858 	if (!cachep->next.next) {
3859 		/* Cache is not active yet. Roll back what we did */
3860 		node--;
3861 		while (node >= 0) {
3862 			if (cachep->nodelists[node]) {
3863 				l3 = cachep->nodelists[node];
3864 
3865 				kfree(l3->shared);
3866 				free_alien_cache(l3->alien);
3867 				kfree(l3);
3868 				cachep->nodelists[node] = NULL;
3869 			}
3870 			node--;
3871 		}
3872 	}
3873 	return -ENOMEM;
3874 }
3875 
3876 struct ccupdate_struct {
3877 	struct kmem_cache *cachep;
3878 	struct array_cache *new[NR_CPUS];
3879 };
3880 
3881 static void do_ccupdate_local(void *info)
3882 {
3883 	struct ccupdate_struct *new = info;
3884 	struct array_cache *old;
3885 
3886 	check_irq_off();
3887 	old = cpu_cache_get(new->cachep);
3888 
3889 	new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
3890 	new->new[smp_processor_id()] = old;
3891 }
3892 
3893 /* Always called with the cache_chain_mutex held */
3894 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3895 				int batchcount, int shared, gfp_t gfp)
3896 {
3897 	struct ccupdate_struct *new;
3898 	int i;
3899 
3900 	new = kzalloc(sizeof(*new), gfp);
3901 	if (!new)
3902 		return -ENOMEM;
3903 
3904 	for_each_online_cpu(i) {
3905 		new->new[i] = alloc_arraycache(cpu_to_node(i), limit,
3906 						batchcount, gfp);
3907 		if (!new->new[i]) {
3908 			for (i--; i >= 0; i--)
3909 				kfree(new->new[i]);
3910 			kfree(new);
3911 			return -ENOMEM;
3912 		}
3913 	}
3914 	new->cachep = cachep;
3915 
3916 	on_each_cpu(do_ccupdate_local, (void *)new, 1);
3917 
3918 	check_irq_on();
3919 	cachep->batchcount = batchcount;
3920 	cachep->limit = limit;
3921 	cachep->shared = shared;
3922 
3923 	for_each_online_cpu(i) {
3924 		struct array_cache *ccold = new->new[i];
3925 		if (!ccold)
3926 			continue;
3927 		spin_lock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3928 		free_block(cachep, ccold->entry, ccold->avail, cpu_to_node(i));
3929 		spin_unlock_irq(&cachep->nodelists[cpu_to_node(i)]->list_lock);
3930 		kfree(ccold);
3931 	}
3932 	kfree(new);
3933 	return alloc_kmemlist(cachep, gfp);
3934 }
3935 
3936 /* Called with cache_chain_mutex held always */
3937 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3938 {
3939 	int err;
3940 	int limit, shared;
3941 
3942 	/*
3943 	 * The head array serves three purposes:
3944 	 * - create a LIFO ordering, i.e. return objects that are cache-warm
3945 	 * - reduce the number of spinlock operations.
3946 	 * - reduce the number of linked list operations on the slab and
3947 	 *   bufctl chains: array operations are cheaper.
3948 	 * The numbers are guessed, we should auto-tune as described by
3949 	 * Bonwick.
3950 	 */
3951 	if (cachep->buffer_size > 131072)
3952 		limit = 1;
3953 	else if (cachep->buffer_size > PAGE_SIZE)
3954 		limit = 8;
3955 	else if (cachep->buffer_size > 1024)
3956 		limit = 24;
3957 	else if (cachep->buffer_size > 256)
3958 		limit = 54;
3959 	else
3960 		limit = 120;
3961 
3962 	/*
3963 	 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3964 	 * allocation behaviour: Most allocs on one cpu, most free operations
3965 	 * on another cpu. For these cases, an efficient object passing between
3966 	 * cpus is necessary. This is provided by a shared array. The array
3967 	 * replaces Bonwick's magazine layer.
3968 	 * On uniprocessor, it's functionally equivalent (but less efficient)
3969 	 * to a larger limit. Thus disabled by default.
3970 	 */
3971 	shared = 0;
3972 	if (cachep->buffer_size <= PAGE_SIZE && num_possible_cpus() > 1)
3973 		shared = 8;
3974 
3975 #if DEBUG
3976 	/*
3977 	 * With debugging enabled, large batchcount lead to excessively long
3978 	 * periods with disabled local interrupts. Limit the batchcount
3979 	 */
3980 	if (limit > 32)
3981 		limit = 32;
3982 #endif
3983 	err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared, gfp);
3984 	if (err)
3985 		printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
3986 		       cachep->name, -err);
3987 	return err;
3988 }
3989 
3990 /*
3991  * Drain an array if it contains any elements taking the l3 lock only if
3992  * necessary. Note that the l3 listlock also protects the array_cache
3993  * if drain_array() is used on the shared array.
3994  */
3995 void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
3996 			 struct array_cache *ac, int force, int node)
3997 {
3998 	int tofree;
3999 
4000 	if (!ac || !ac->avail)
4001 		return;
4002 	if (ac->touched && !force) {
4003 		ac->touched = 0;
4004 	} else {
4005 		spin_lock_irq(&l3->list_lock);
4006 		if (ac->avail) {
4007 			tofree = force ? ac->avail : (ac->limit + 4) / 5;
4008 			if (tofree > ac->avail)
4009 				tofree = (ac->avail + 1) / 2;
4010 			free_block(cachep, ac->entry, tofree, node);
4011 			ac->avail -= tofree;
4012 			memmove(ac->entry, &(ac->entry[tofree]),
4013 				sizeof(void *) * ac->avail);
4014 		}
4015 		spin_unlock_irq(&l3->list_lock);
4016 	}
4017 }
4018 
4019 /**
4020  * cache_reap - Reclaim memory from caches.
4021  * @w: work descriptor
4022  *
4023  * Called from workqueue/eventd every few seconds.
4024  * Purpose:
4025  * - clear the per-cpu caches for this CPU.
4026  * - return freeable pages to the main free memory pool.
4027  *
4028  * If we cannot acquire the cache chain mutex then just give up - we'll try
4029  * again on the next iteration.
4030  */
4031 static void cache_reap(struct work_struct *w)
4032 {
4033 	struct kmem_cache *searchp;
4034 	struct kmem_list3 *l3;
4035 	int node = numa_node_id();
4036 	struct delayed_work *work = to_delayed_work(w);
4037 
4038 	if (!mutex_trylock(&cache_chain_mutex))
4039 		/* Give up. Setup the next iteration. */
4040 		goto out;
4041 
4042 	list_for_each_entry(searchp, &cache_chain, next) {
4043 		check_irq_on();
4044 
4045 		/*
4046 		 * We only take the l3 lock if absolutely necessary and we
4047 		 * have established with reasonable certainty that
4048 		 * we can do some work if the lock was obtained.
4049 		 */
4050 		l3 = searchp->nodelists[node];
4051 
4052 		reap_alien(searchp, l3);
4053 
4054 		drain_array(searchp, l3, cpu_cache_get(searchp), 0, node);
4055 
4056 		/*
4057 		 * These are racy checks but it does not matter
4058 		 * if we skip one check or scan twice.
4059 		 */
4060 		if (time_after(l3->next_reap, jiffies))
4061 			goto next;
4062 
4063 		l3->next_reap = jiffies + REAPTIMEOUT_LIST3;
4064 
4065 		drain_array(searchp, l3, l3->shared, 0, node);
4066 
4067 		if (l3->free_touched)
4068 			l3->free_touched = 0;
4069 		else {
4070 			int freed;
4071 
4072 			freed = drain_freelist(searchp, l3, (l3->free_limit +
4073 				5 * searchp->num - 1) / (5 * searchp->num));
4074 			STATS_ADD_REAPED(searchp, freed);
4075 		}
4076 next:
4077 		cond_resched();
4078 	}
4079 	check_irq_on();
4080 	mutex_unlock(&cache_chain_mutex);
4081 	next_reap_node();
4082 out:
4083 	/* Set up the next iteration */
4084 	schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
4085 }
4086 
4087 #ifdef CONFIG_SLABINFO
4088 
4089 static void print_slabinfo_header(struct seq_file *m)
4090 {
4091 	/*
4092 	 * Output format version, so at least we can change it
4093 	 * without _too_ many complaints.
4094 	 */
4095 #if STATS
4096 	seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
4097 #else
4098 	seq_puts(m, "slabinfo - version: 2.1\n");
4099 #endif
4100 	seq_puts(m, "# name            <active_objs> <num_objs> <objsize> "
4101 		 "<objperslab> <pagesperslab>");
4102 	seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
4103 	seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
4104 #if STATS
4105 	seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> "
4106 		 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
4107 	seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
4108 #endif
4109 	seq_putc(m, '\n');
4110 }
4111 
4112 static void *s_start(struct seq_file *m, loff_t *pos)
4113 {
4114 	loff_t n = *pos;
4115 
4116 	mutex_lock(&cache_chain_mutex);
4117 	if (!n)
4118 		print_slabinfo_header(m);
4119 
4120 	return seq_list_start(&cache_chain, *pos);
4121 }
4122 
4123 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
4124 {
4125 	return seq_list_next(p, &cache_chain, pos);
4126 }
4127 
4128 static void s_stop(struct seq_file *m, void *p)
4129 {
4130 	mutex_unlock(&cache_chain_mutex);
4131 }
4132 
4133 static int s_show(struct seq_file *m, void *p)
4134 {
4135 	struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
4136 	struct slab *slabp;
4137 	unsigned long active_objs;
4138 	unsigned long num_objs;
4139 	unsigned long active_slabs = 0;
4140 	unsigned long num_slabs, free_objects = 0, shared_avail = 0;
4141 	const char *name;
4142 	char *error = NULL;
4143 	int node;
4144 	struct kmem_list3 *l3;
4145 
4146 	active_objs = 0;
4147 	num_slabs = 0;
4148 	for_each_online_node(node) {
4149 		l3 = cachep->nodelists[node];
4150 		if (!l3)
4151 			continue;
4152 
4153 		check_irq_on();
4154 		spin_lock_irq(&l3->list_lock);
4155 
4156 		list_for_each_entry(slabp, &l3->slabs_full, list) {
4157 			if (slabp->inuse != cachep->num && !error)
4158 				error = "slabs_full accounting error";
4159 			active_objs += cachep->num;
4160 			active_slabs++;
4161 		}
4162 		list_for_each_entry(slabp, &l3->slabs_partial, list) {
4163 			if (slabp->inuse == cachep->num && !error)
4164 				error = "slabs_partial inuse accounting error";
4165 			if (!slabp->inuse && !error)
4166 				error = "slabs_partial/inuse accounting error";
4167 			active_objs += slabp->inuse;
4168 			active_slabs++;
4169 		}
4170 		list_for_each_entry(slabp, &l3->slabs_free, list) {
4171 			if (slabp->inuse && !error)
4172 				error = "slabs_free/inuse accounting error";
4173 			num_slabs++;
4174 		}
4175 		free_objects += l3->free_objects;
4176 		if (l3->shared)
4177 			shared_avail += l3->shared->avail;
4178 
4179 		spin_unlock_irq(&l3->list_lock);
4180 	}
4181 	num_slabs += active_slabs;
4182 	num_objs = num_slabs * cachep->num;
4183 	if (num_objs - active_objs != free_objects && !error)
4184 		error = "free_objects accounting error";
4185 
4186 	name = cachep->name;
4187 	if (error)
4188 		printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
4189 
4190 	seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
4191 		   name, active_objs, num_objs, cachep->buffer_size,
4192 		   cachep->num, (1 << cachep->gfporder));
4193 	seq_printf(m, " : tunables %4u %4u %4u",
4194 		   cachep->limit, cachep->batchcount, cachep->shared);
4195 	seq_printf(m, " : slabdata %6lu %6lu %6lu",
4196 		   active_slabs, num_slabs, shared_avail);
4197 #if STATS
4198 	{			/* list3 stats */
4199 		unsigned long high = cachep->high_mark;
4200 		unsigned long allocs = cachep->num_allocations;
4201 		unsigned long grown = cachep->grown;
4202 		unsigned long reaped = cachep->reaped;
4203 		unsigned long errors = cachep->errors;
4204 		unsigned long max_freeable = cachep->max_freeable;
4205 		unsigned long node_allocs = cachep->node_allocs;
4206 		unsigned long node_frees = cachep->node_frees;
4207 		unsigned long overflows = cachep->node_overflow;
4208 
4209 		seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu \
4210 				%4lu %4lu %4lu %4lu %4lu", allocs, high, grown,
4211 				reaped, errors, max_freeable, node_allocs,
4212 				node_frees, overflows);
4213 	}
4214 	/* cpu stats */
4215 	{
4216 		unsigned long allochit = atomic_read(&cachep->allochit);
4217 		unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4218 		unsigned long freehit = atomic_read(&cachep->freehit);
4219 		unsigned long freemiss = atomic_read(&cachep->freemiss);
4220 
4221 		seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4222 			   allochit, allocmiss, freehit, freemiss);
4223 	}
4224 #endif
4225 	seq_putc(m, '\n');
4226 	return 0;
4227 }
4228 
4229 /*
4230  * slabinfo_op - iterator that generates /proc/slabinfo
4231  *
4232  * Output layout:
4233  * cache-name
4234  * num-active-objs
4235  * total-objs
4236  * object size
4237  * num-active-slabs
4238  * total-slabs
4239  * num-pages-per-slab
4240  * + further values on SMP and with statistics enabled
4241  */
4242 
4243 static const struct seq_operations slabinfo_op = {
4244 	.start = s_start,
4245 	.next = s_next,
4246 	.stop = s_stop,
4247 	.show = s_show,
4248 };
4249 
4250 #define MAX_SLABINFO_WRITE 128
4251 /**
4252  * slabinfo_write - Tuning for the slab allocator
4253  * @file: unused
4254  * @buffer: user buffer
4255  * @count: data length
4256  * @ppos: unused
4257  */
4258 ssize_t slabinfo_write(struct file *file, const char __user * buffer,
4259 		       size_t count, loff_t *ppos)
4260 {
4261 	char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4262 	int limit, batchcount, shared, res;
4263 	struct kmem_cache *cachep;
4264 
4265 	if (count > MAX_SLABINFO_WRITE)
4266 		return -EINVAL;
4267 	if (copy_from_user(&kbuf, buffer, count))
4268 		return -EFAULT;
4269 	kbuf[MAX_SLABINFO_WRITE] = '\0';
4270 
4271 	tmp = strchr(kbuf, ' ');
4272 	if (!tmp)
4273 		return -EINVAL;
4274 	*tmp = '\0';
4275 	tmp++;
4276 	if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4277 		return -EINVAL;
4278 
4279 	/* Find the cache in the chain of caches. */
4280 	mutex_lock(&cache_chain_mutex);
4281 	res = -EINVAL;
4282 	list_for_each_entry(cachep, &cache_chain, next) {
4283 		if (!strcmp(cachep->name, kbuf)) {
4284 			if (limit < 1 || batchcount < 1 ||
4285 					batchcount > limit || shared < 0) {
4286 				res = 0;
4287 			} else {
4288 				res = do_tune_cpucache(cachep, limit,
4289 						       batchcount, shared,
4290 						       GFP_KERNEL);
4291 			}
4292 			break;
4293 		}
4294 	}
4295 	mutex_unlock(&cache_chain_mutex);
4296 	if (res >= 0)
4297 		res = count;
4298 	return res;
4299 }
4300 
4301 static int slabinfo_open(struct inode *inode, struct file *file)
4302 {
4303 	return seq_open(file, &slabinfo_op);
4304 }
4305 
4306 static const struct file_operations proc_slabinfo_operations = {
4307 	.open		= slabinfo_open,
4308 	.read		= seq_read,
4309 	.write		= slabinfo_write,
4310 	.llseek		= seq_lseek,
4311 	.release	= seq_release,
4312 };
4313 
4314 #ifdef CONFIG_DEBUG_SLAB_LEAK
4315 
4316 static void *leaks_start(struct seq_file *m, loff_t *pos)
4317 {
4318 	mutex_lock(&cache_chain_mutex);
4319 	return seq_list_start(&cache_chain, *pos);
4320 }
4321 
4322 static inline int add_caller(unsigned long *n, unsigned long v)
4323 {
4324 	unsigned long *p;
4325 	int l;
4326 	if (!v)
4327 		return 1;
4328 	l = n[1];
4329 	p = n + 2;
4330 	while (l) {
4331 		int i = l/2;
4332 		unsigned long *q = p + 2 * i;
4333 		if (*q == v) {
4334 			q[1]++;
4335 			return 1;
4336 		}
4337 		if (*q > v) {
4338 			l = i;
4339 		} else {
4340 			p = q + 2;
4341 			l -= i + 1;
4342 		}
4343 	}
4344 	if (++n[1] == n[0])
4345 		return 0;
4346 	memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4347 	p[0] = v;
4348 	p[1] = 1;
4349 	return 1;
4350 }
4351 
4352 static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
4353 {
4354 	void *p;
4355 	int i;
4356 	if (n[0] == n[1])
4357 		return;
4358 	for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) {
4359 		if (slab_bufctl(s)[i] != BUFCTL_ACTIVE)
4360 			continue;
4361 		if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4362 			return;
4363 	}
4364 }
4365 
4366 static void show_symbol(struct seq_file *m, unsigned long address)
4367 {
4368 #ifdef CONFIG_KALLSYMS
4369 	unsigned long offset, size;
4370 	char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4371 
4372 	if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4373 		seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4374 		if (modname[0])
4375 			seq_printf(m, " [%s]", modname);
4376 		return;
4377 	}
4378 #endif
4379 	seq_printf(m, "%p", (void *)address);
4380 }
4381 
4382 static int leaks_show(struct seq_file *m, void *p)
4383 {
4384 	struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next);
4385 	struct slab *slabp;
4386 	struct kmem_list3 *l3;
4387 	const char *name;
4388 	unsigned long *n = m->private;
4389 	int node;
4390 	int i;
4391 
4392 	if (!(cachep->flags & SLAB_STORE_USER))
4393 		return 0;
4394 	if (!(cachep->flags & SLAB_RED_ZONE))
4395 		return 0;
4396 
4397 	/* OK, we can do it */
4398 
4399 	n[1] = 0;
4400 
4401 	for_each_online_node(node) {
4402 		l3 = cachep->nodelists[node];
4403 		if (!l3)
4404 			continue;
4405 
4406 		check_irq_on();
4407 		spin_lock_irq(&l3->list_lock);
4408 
4409 		list_for_each_entry(slabp, &l3->slabs_full, list)
4410 			handle_slab(n, cachep, slabp);
4411 		list_for_each_entry(slabp, &l3->slabs_partial, list)
4412 			handle_slab(n, cachep, slabp);
4413 		spin_unlock_irq(&l3->list_lock);
4414 	}
4415 	name = cachep->name;
4416 	if (n[0] == n[1]) {
4417 		/* Increase the buffer size */
4418 		mutex_unlock(&cache_chain_mutex);
4419 		m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4420 		if (!m->private) {
4421 			/* Too bad, we are really out */
4422 			m->private = n;
4423 			mutex_lock(&cache_chain_mutex);
4424 			return -ENOMEM;
4425 		}
4426 		*(unsigned long *)m->private = n[0] * 2;
4427 		kfree(n);
4428 		mutex_lock(&cache_chain_mutex);
4429 		/* Now make sure this entry will be retried */
4430 		m->count = m->size;
4431 		return 0;
4432 	}
4433 	for (i = 0; i < n[1]; i++) {
4434 		seq_printf(m, "%s: %lu ", name, n[2*i+3]);
4435 		show_symbol(m, n[2*i+2]);
4436 		seq_putc(m, '\n');
4437 	}
4438 
4439 	return 0;
4440 }
4441 
4442 static const struct seq_operations slabstats_op = {
4443 	.start = leaks_start,
4444 	.next = s_next,
4445 	.stop = s_stop,
4446 	.show = leaks_show,
4447 };
4448 
4449 static int slabstats_open(struct inode *inode, struct file *file)
4450 {
4451 	unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL);
4452 	int ret = -ENOMEM;
4453 	if (n) {
4454 		ret = seq_open(file, &slabstats_op);
4455 		if (!ret) {
4456 			struct seq_file *m = file->private_data;
4457 			*n = PAGE_SIZE / (2 * sizeof(unsigned long));
4458 			m->private = n;
4459 			n = NULL;
4460 		}
4461 		kfree(n);
4462 	}
4463 	return ret;
4464 }
4465 
4466 static const struct file_operations proc_slabstats_operations = {
4467 	.open		= slabstats_open,
4468 	.read		= seq_read,
4469 	.llseek		= seq_lseek,
4470 	.release	= seq_release_private,
4471 };
4472 #endif
4473 
4474 static int __init slab_proc_init(void)
4475 {
4476 	proc_create("slabinfo",S_IWUSR|S_IRUGO,NULL,&proc_slabinfo_operations);
4477 #ifdef CONFIG_DEBUG_SLAB_LEAK
4478 	proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4479 #endif
4480 	return 0;
4481 }
4482 module_init(slab_proc_init);
4483 #endif
4484 
4485 /**
4486  * ksize - get the actual amount of memory allocated for a given object
4487  * @objp: Pointer to the object
4488  *
4489  * kmalloc may internally round up allocations and return more memory
4490  * than requested. ksize() can be used to determine the actual amount of
4491  * memory allocated. The caller may use this additional memory, even though
4492  * a smaller amount of memory was initially specified with the kmalloc call.
4493  * The caller must guarantee that objp points to a valid object previously
4494  * allocated with either kmalloc() or kmem_cache_alloc(). The object
4495  * must not be freed during the duration of the call.
4496  */
4497 size_t ksize(const void *objp)
4498 {
4499 	BUG_ON(!objp);
4500 	if (unlikely(objp == ZERO_SIZE_PTR))
4501 		return 0;
4502 
4503 	return obj_size(virt_to_cache(objp));
4504 }
4505 EXPORT_SYMBOL(ksize);
4506