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TOMOYO Linux Cross Reference
Linux/mm/slab.c

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

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