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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 'slab_mutex'.
 72  *      The sem is only needed when accessing/extending the cache-chain, which
 73  *      can never happen inside an interrupt (kmem_cache_create(),
 74  *      kmem_cache_shrink() and kmem_cache_reap()).
 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/rcupdate.h>
106 #include        <linux/string.h>
107 #include        <linux/uaccess.h>
108 #include        <linux/nodemask.h>
109 #include        <linux/kmemleak.h>
110 #include        <linux/mempolicy.h>
111 #include        <linux/mutex.h>
112 #include        <linux/fault-inject.h>
113 #include        <linux/rtmutex.h>
114 #include        <linux/reciprocal_div.h>
115 #include        <linux/debugobjects.h>
116 #include        <linux/kmemcheck.h>
117 #include        <linux/memory.h>
118 #include        <linux/prefetch.h>
119 
120 #include        <net/sock.h>
121 
122 #include        <asm/cacheflush.h>
123 #include        <asm/tlbflush.h>
124 #include        <asm/page.h>
125 
126 #include <trace/events/kmem.h>
127 
128 #include        "internal.h"
129 
130 #include        "slab.h"
131 
132 /*
133  * DEBUG        - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
134  *                0 for faster, smaller code (especially in the critical paths).
135  *
136  * STATS        - 1 to collect stats for /proc/slabinfo.
137  *                0 for faster, smaller code (especially in the critical paths).
138  *
139  * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
140  */
141 
142 #ifdef CONFIG_DEBUG_SLAB
143 #define DEBUG           1
144 #define STATS           1
145 #define FORCED_DEBUG    1
146 #else
147 #define DEBUG           0
148 #define STATS           0
149 #define FORCED_DEBUG    0
150 #endif
151 
152 /* Shouldn't this be in a header file somewhere? */
153 #define BYTES_PER_WORD          sizeof(void *)
154 #define REDZONE_ALIGN           max(BYTES_PER_WORD, __alignof__(unsigned long long))
155 
156 #ifndef ARCH_KMALLOC_FLAGS
157 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
158 #endif
159 
160 #define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \
161                                 <= SLAB_OBJ_MIN_SIZE) ? 1 : 0)
162 
163 #if FREELIST_BYTE_INDEX
164 typedef unsigned char freelist_idx_t;
165 #else
166 typedef unsigned short freelist_idx_t;
167 #endif
168 
169 #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1)
170 
171 /*
172  * true if a page was allocated from pfmemalloc reserves for network-based
173  * swap
174  */
175 static bool pfmemalloc_active __read_mostly;
176 
177 /*
178  * struct array_cache
179  *
180  * Purpose:
181  * - LIFO ordering, to hand out cache-warm objects from _alloc
182  * - reduce the number of linked list operations
183  * - reduce spinlock operations
184  *
185  * The limit is stored in the per-cpu structure to reduce the data cache
186  * footprint.
187  *
188  */
189 struct array_cache {
190         unsigned int avail;
191         unsigned int limit;
192         unsigned int batchcount;
193         unsigned int touched;
194         void *entry[];  /*
195                          * Must have this definition in here for the proper
196                          * alignment of array_cache. Also simplifies accessing
197                          * the entries.
198                          *
199                          * Entries should not be directly dereferenced as
200                          * entries belonging to slabs marked pfmemalloc will
201                          * have the lower bits set SLAB_OBJ_PFMEMALLOC
202                          */
203 };
204 
205 struct alien_cache {
206         spinlock_t lock;
207         struct array_cache ac;
208 };
209 
210 #define SLAB_OBJ_PFMEMALLOC     1
211 static inline bool is_obj_pfmemalloc(void *objp)
212 {
213         return (unsigned long)objp & SLAB_OBJ_PFMEMALLOC;
214 }
215 
216 static inline void set_obj_pfmemalloc(void **objp)
217 {
218         *objp = (void *)((unsigned long)*objp | SLAB_OBJ_PFMEMALLOC);
219         return;
220 }
221 
222 static inline void clear_obj_pfmemalloc(void **objp)
223 {
224         *objp = (void *)((unsigned long)*objp & ~SLAB_OBJ_PFMEMALLOC);
225 }
226 
227 /*
228  * bootstrap: The caches do not work without cpuarrays anymore, but the
229  * cpuarrays are allocated from the generic caches...
230  */
231 #define BOOT_CPUCACHE_ENTRIES   1
232 struct arraycache_init {
233         struct array_cache cache;
234         void *entries[BOOT_CPUCACHE_ENTRIES];
235 };
236 
237 /*
238  * Need this for bootstrapping a per node allocator.
239  */
240 #define NUM_INIT_LISTS (2 * MAX_NUMNODES)
241 static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS];
242 #define CACHE_CACHE 0
243 #define SIZE_NODE (MAX_NUMNODES)
244 
245 static int drain_freelist(struct kmem_cache *cache,
246                         struct kmem_cache_node *n, int tofree);
247 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
248                         int node, struct list_head *list);
249 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list);
250 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
251 static void cache_reap(struct work_struct *unused);
252 
253 static int slab_early_init = 1;
254 
255 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
256 
257 static void kmem_cache_node_init(struct kmem_cache_node *parent)
258 {
259         INIT_LIST_HEAD(&parent->slabs_full);
260         INIT_LIST_HEAD(&parent->slabs_partial);
261         INIT_LIST_HEAD(&parent->slabs_free);
262         parent->shared = NULL;
263         parent->alien = NULL;
264         parent->colour_next = 0;
265         spin_lock_init(&parent->list_lock);
266         parent->free_objects = 0;
267         parent->free_touched = 0;
268 }
269 
270 #define MAKE_LIST(cachep, listp, slab, nodeid)                          \
271         do {                                                            \
272                 INIT_LIST_HEAD(listp);                                  \
273                 list_splice(&get_node(cachep, nodeid)->slab, listp);    \
274         } while (0)
275 
276 #define MAKE_ALL_LISTS(cachep, ptr, nodeid)                             \
277         do {                                                            \
278         MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid);  \
279         MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
280         MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid);  \
281         } while (0)
282 
283 #define CFLGS_OFF_SLAB          (0x80000000UL)
284 #define OFF_SLAB(x)     ((x)->flags & CFLGS_OFF_SLAB)
285 
286 #define BATCHREFILL_LIMIT       16
287 /*
288  * Optimization question: fewer reaps means less probability for unnessary
289  * cpucache drain/refill cycles.
290  *
291  * OTOH the cpuarrays can contain lots of objects,
292  * which could lock up otherwise freeable slabs.
293  */
294 #define REAPTIMEOUT_AC          (2*HZ)
295 #define REAPTIMEOUT_NODE        (4*HZ)
296 
297 #if STATS
298 #define STATS_INC_ACTIVE(x)     ((x)->num_active++)
299 #define STATS_DEC_ACTIVE(x)     ((x)->num_active--)
300 #define STATS_INC_ALLOCED(x)    ((x)->num_allocations++)
301 #define STATS_INC_GROWN(x)      ((x)->grown++)
302 #define STATS_ADD_REAPED(x,y)   ((x)->reaped += (y))
303 #define STATS_SET_HIGH(x)                                               \
304         do {                                                            \
305                 if ((x)->num_active > (x)->high_mark)                   \
306                         (x)->high_mark = (x)->num_active;               \
307         } while (0)
308 #define STATS_INC_ERR(x)        ((x)->errors++)
309 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
310 #define STATS_INC_NODEFREES(x)  ((x)->node_frees++)
311 #define STATS_INC_ACOVERFLOW(x)   ((x)->node_overflow++)
312 #define STATS_SET_FREEABLE(x, i)                                        \
313         do {                                                            \
314                 if ((x)->max_freeable < i)                              \
315                         (x)->max_freeable = i;                          \
316         } while (0)
317 #define STATS_INC_ALLOCHIT(x)   atomic_inc(&(x)->allochit)
318 #define STATS_INC_ALLOCMISS(x)  atomic_inc(&(x)->allocmiss)
319 #define STATS_INC_FREEHIT(x)    atomic_inc(&(x)->freehit)
320 #define STATS_INC_FREEMISS(x)   atomic_inc(&(x)->freemiss)
321 #else
322 #define STATS_INC_ACTIVE(x)     do { } while (0)
323 #define STATS_DEC_ACTIVE(x)     do { } while (0)
324 #define STATS_INC_ALLOCED(x)    do { } while (0)
325 #define STATS_INC_GROWN(x)      do { } while (0)
326 #define STATS_ADD_REAPED(x,y)   do { (void)(y); } while (0)
327 #define STATS_SET_HIGH(x)       do { } while (0)
328 #define STATS_INC_ERR(x)        do { } while (0)
329 #define STATS_INC_NODEALLOCS(x) do { } while (0)
330 #define STATS_INC_NODEFREES(x)  do { } while (0)
331 #define STATS_INC_ACOVERFLOW(x)   do { } while (0)
332 #define STATS_SET_FREEABLE(x, i) do { } while (0)
333 #define STATS_INC_ALLOCHIT(x)   do { } while (0)
334 #define STATS_INC_ALLOCMISS(x)  do { } while (0)
335 #define STATS_INC_FREEHIT(x)    do { } while (0)
336 #define STATS_INC_FREEMISS(x)   do { } while (0)
337 #endif
338 
339 #if DEBUG
340 
341 /*
342  * memory layout of objects:
343  * 0            : objp
344  * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
345  *              the end of an object is aligned with the end of the real
346  *              allocation. Catches writes behind the end of the allocation.
347  * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
348  *              redzone word.
349  * cachep->obj_offset: The real object.
350  * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
351  * cachep->size - 1* BYTES_PER_WORD: last caller address
352  *                                      [BYTES_PER_WORD long]
353  */
354 static int obj_offset(struct kmem_cache *cachep)
355 {
356         return cachep->obj_offset;
357 }
358 
359 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
360 {
361         BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
362         return (unsigned long long*) (objp + obj_offset(cachep) -
363                                       sizeof(unsigned long long));
364 }
365 
366 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
367 {
368         BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
369         if (cachep->flags & SLAB_STORE_USER)
370                 return (unsigned long long *)(objp + cachep->size -
371                                               sizeof(unsigned long long) -
372                                               REDZONE_ALIGN);
373         return (unsigned long long *) (objp + cachep->size -
374                                        sizeof(unsigned long long));
375 }
376 
377 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
378 {
379         BUG_ON(!(cachep->flags & SLAB_STORE_USER));
380         return (void **)(objp + cachep->size - BYTES_PER_WORD);
381 }
382 
383 #else
384 
385 #define obj_offset(x)                   0
386 #define dbg_redzone1(cachep, objp)      ({BUG(); (unsigned long long *)NULL;})
387 #define dbg_redzone2(cachep, objp)      ({BUG(); (unsigned long long *)NULL;})
388 #define dbg_userword(cachep, objp)      ({BUG(); (void **)NULL;})
389 
390 #endif
391 
392 #define OBJECT_FREE (0)
393 #define OBJECT_ACTIVE (1)
394 
395 #ifdef CONFIG_DEBUG_SLAB_LEAK
396 
397 static void set_obj_status(struct page *page, int idx, int val)
398 {
399         int freelist_size;
400         char *status;
401         struct kmem_cache *cachep = page->slab_cache;
402 
403         freelist_size = cachep->num * sizeof(freelist_idx_t);
404         status = (char *)page->freelist + freelist_size;
405         status[idx] = val;
406 }
407 
408 static inline unsigned int get_obj_status(struct page *page, int idx)
409 {
410         int freelist_size;
411         char *status;
412         struct kmem_cache *cachep = page->slab_cache;
413 
414         freelist_size = cachep->num * sizeof(freelist_idx_t);
415         status = (char *)page->freelist + freelist_size;
416 
417         return status[idx];
418 }
419 
420 #else
421 static inline void set_obj_status(struct page *page, int idx, int val) {}
422 
423 #endif
424 
425 /*
426  * Do not go above this order unless 0 objects fit into the slab or
427  * overridden on the command line.
428  */
429 #define SLAB_MAX_ORDER_HI       1
430 #define SLAB_MAX_ORDER_LO       0
431 static int slab_max_order = SLAB_MAX_ORDER_LO;
432 static bool slab_max_order_set __initdata;
433 
434 static inline struct kmem_cache *virt_to_cache(const void *obj)
435 {
436         struct page *page = virt_to_head_page(obj);
437         return page->slab_cache;
438 }
439 
440 static inline void *index_to_obj(struct kmem_cache *cache, struct page *page,
441                                  unsigned int idx)
442 {
443         return page->s_mem + cache->size * idx;
444 }
445 
446 /*
447  * We want to avoid an expensive divide : (offset / cache->size)
448  *   Using the fact that size is a constant for a particular cache,
449  *   we can replace (offset / cache->size) by
450  *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
451  */
452 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
453                                         const struct page *page, void *obj)
454 {
455         u32 offset = (obj - page->s_mem);
456         return reciprocal_divide(offset, cache->reciprocal_buffer_size);
457 }
458 
459 /* internal cache of cache description objs */
460 static struct kmem_cache kmem_cache_boot = {
461         .batchcount = 1,
462         .limit = BOOT_CPUCACHE_ENTRIES,
463         .shared = 1,
464         .size = sizeof(struct kmem_cache),
465         .name = "kmem_cache",
466 };
467 
468 #define BAD_ALIEN_MAGIC 0x01020304ul
469 
470 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
471 
472 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
473 {
474         return this_cpu_ptr(cachep->cpu_cache);
475 }
476 
477 static size_t calculate_freelist_size(int nr_objs, size_t align)
478 {
479         size_t freelist_size;
480 
481         freelist_size = nr_objs * sizeof(freelist_idx_t);
482         if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
483                 freelist_size += nr_objs * sizeof(char);
484 
485         if (align)
486                 freelist_size = ALIGN(freelist_size, align);
487 
488         return freelist_size;
489 }
490 
491 static int calculate_nr_objs(size_t slab_size, size_t buffer_size,
492                                 size_t idx_size, size_t align)
493 {
494         int nr_objs;
495         size_t remained_size;
496         size_t freelist_size;
497         int extra_space = 0;
498 
499         if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
500                 extra_space = sizeof(char);
501         /*
502          * Ignore padding for the initial guess. The padding
503          * is at most @align-1 bytes, and @buffer_size is at
504          * least @align. In the worst case, this result will
505          * be one greater than the number of objects that fit
506          * into the memory allocation when taking the padding
507          * into account.
508          */
509         nr_objs = slab_size / (buffer_size + idx_size + extra_space);
510 
511         /*
512          * This calculated number will be either the right
513          * amount, or one greater than what we want.
514          */
515         remained_size = slab_size - nr_objs * buffer_size;
516         freelist_size = calculate_freelist_size(nr_objs, align);
517         if (remained_size < freelist_size)
518                 nr_objs--;
519 
520         return nr_objs;
521 }
522 
523 /*
524  * Calculate the number of objects and left-over bytes for a given buffer size.
525  */
526 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
527                            size_t align, int flags, size_t *left_over,
528                            unsigned int *num)
529 {
530         int nr_objs;
531         size_t mgmt_size;
532         size_t slab_size = PAGE_SIZE << gfporder;
533 
534         /*
535          * The slab management structure can be either off the slab or
536          * on it. For the latter case, the memory allocated for a
537          * slab is used for:
538          *
539          * - One unsigned int for each object
540          * - Padding to respect alignment of @align
541          * - @buffer_size bytes for each object
542          *
543          * If the slab management structure is off the slab, then the
544          * alignment will already be calculated into the size. Because
545          * the slabs are all pages aligned, the objects will be at the
546          * correct alignment when allocated.
547          */
548         if (flags & CFLGS_OFF_SLAB) {
549                 mgmt_size = 0;
550                 nr_objs = slab_size / buffer_size;
551 
552         } else {
553                 nr_objs = calculate_nr_objs(slab_size, buffer_size,
554                                         sizeof(freelist_idx_t), align);
555                 mgmt_size = calculate_freelist_size(nr_objs, align);
556         }
557         *num = nr_objs;
558         *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
559 }
560 
561 #if DEBUG
562 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
563 
564 static void __slab_error(const char *function, struct kmem_cache *cachep,
565                         char *msg)
566 {
567         printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
568                function, cachep->name, msg);
569         dump_stack();
570         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
571 }
572 #endif
573 
574 /*
575  * By default on NUMA we use alien caches to stage the freeing of
576  * objects allocated from other nodes. This causes massive memory
577  * inefficiencies when using fake NUMA setup to split memory into a
578  * large number of small nodes, so it can be disabled on the command
579  * line
580   */
581 
582 static int use_alien_caches __read_mostly = 1;
583 static int __init noaliencache_setup(char *s)
584 {
585         use_alien_caches = 0;
586         return 1;
587 }
588 __setup("noaliencache", noaliencache_setup);
589 
590 static int __init slab_max_order_setup(char *str)
591 {
592         get_option(&str, &slab_max_order);
593         slab_max_order = slab_max_order < 0 ? 0 :
594                                 min(slab_max_order, MAX_ORDER - 1);
595         slab_max_order_set = true;
596 
597         return 1;
598 }
599 __setup("slab_max_order=", slab_max_order_setup);
600 
601 #ifdef CONFIG_NUMA
602 /*
603  * Special reaping functions for NUMA systems called from cache_reap().
604  * These take care of doing round robin flushing of alien caches (containing
605  * objects freed on different nodes from which they were allocated) and the
606  * flushing of remote pcps by calling drain_node_pages.
607  */
608 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
609 
610 static void init_reap_node(int cpu)
611 {
612         int node;
613 
614         node = next_node(cpu_to_mem(cpu), node_online_map);
615         if (node == MAX_NUMNODES)
616                 node = first_node(node_online_map);
617 
618         per_cpu(slab_reap_node, cpu) = node;
619 }
620 
621 static void next_reap_node(void)
622 {
623         int node = __this_cpu_read(slab_reap_node);
624 
625         node = next_node(node, node_online_map);
626         if (unlikely(node >= MAX_NUMNODES))
627                 node = first_node(node_online_map);
628         __this_cpu_write(slab_reap_node, node);
629 }
630 
631 #else
632 #define init_reap_node(cpu) do { } while (0)
633 #define next_reap_node(void) do { } while (0)
634 #endif
635 
636 /*
637  * Initiate the reap timer running on the target CPU.  We run at around 1 to 2Hz
638  * via the workqueue/eventd.
639  * Add the CPU number into the expiration time to minimize the possibility of
640  * the CPUs getting into lockstep and contending for the global cache chain
641  * lock.
642  */
643 static void start_cpu_timer(int cpu)
644 {
645         struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
646 
647         /*
648          * When this gets called from do_initcalls via cpucache_init(),
649          * init_workqueues() has already run, so keventd will be setup
650          * at that time.
651          */
652         if (keventd_up() && reap_work->work.func == NULL) {
653                 init_reap_node(cpu);
654                 INIT_DEFERRABLE_WORK(reap_work, cache_reap);
655                 schedule_delayed_work_on(cpu, reap_work,
656                                         __round_jiffies_relative(HZ, cpu));
657         }
658 }
659 
660 static void init_arraycache(struct array_cache *ac, int limit, int batch)
661 {
662         /*
663          * The array_cache structures contain pointers to free object.
664          * However, when such objects are allocated or transferred to another
665          * cache the pointers are not cleared and they could be counted as
666          * valid references during a kmemleak scan. Therefore, kmemleak must
667          * not scan such objects.
668          */
669         kmemleak_no_scan(ac);
670         if (ac) {
671                 ac->avail = 0;
672                 ac->limit = limit;
673                 ac->batchcount = batch;
674                 ac->touched = 0;
675         }
676 }
677 
678 static struct array_cache *alloc_arraycache(int node, int entries,
679                                             int batchcount, gfp_t gfp)
680 {
681         size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache);
682         struct array_cache *ac = NULL;
683 
684         ac = kmalloc_node(memsize, gfp, node);
685         init_arraycache(ac, entries, batchcount);
686         return ac;
687 }
688 
689 static inline bool is_slab_pfmemalloc(struct page *page)
690 {
691         return PageSlabPfmemalloc(page);
692 }
693 
694 /* Clears pfmemalloc_active if no slabs have pfmalloc set */
695 static void recheck_pfmemalloc_active(struct kmem_cache *cachep,
696                                                 struct array_cache *ac)
697 {
698         struct kmem_cache_node *n = get_node(cachep, numa_mem_id());
699         struct page *page;
700         unsigned long flags;
701 
702         if (!pfmemalloc_active)
703                 return;
704 
705         spin_lock_irqsave(&n->list_lock, flags);
706         list_for_each_entry(page, &n->slabs_full, lru)
707                 if (is_slab_pfmemalloc(page))
708                         goto out;
709 
710         list_for_each_entry(page, &n->slabs_partial, lru)
711                 if (is_slab_pfmemalloc(page))
712                         goto out;
713 
714         list_for_each_entry(page, &n->slabs_free, lru)
715                 if (is_slab_pfmemalloc(page))
716                         goto out;
717 
718         pfmemalloc_active = false;
719 out:
720         spin_unlock_irqrestore(&n->list_lock, flags);
721 }
722 
723 static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
724                                                 gfp_t flags, bool force_refill)
725 {
726         int i;
727         void *objp = ac->entry[--ac->avail];
728 
729         /* Ensure the caller is allowed to use objects from PFMEMALLOC slab */
730         if (unlikely(is_obj_pfmemalloc(objp))) {
731                 struct kmem_cache_node *n;
732 
733                 if (gfp_pfmemalloc_allowed(flags)) {
734                         clear_obj_pfmemalloc(&objp);
735                         return objp;
736                 }
737 
738                 /* The caller cannot use PFMEMALLOC objects, find another one */
739                 for (i = 0; i < ac->avail; i++) {
740                         /* If a !PFMEMALLOC object is found, swap them */
741                         if (!is_obj_pfmemalloc(ac->entry[i])) {
742                                 objp = ac->entry[i];
743                                 ac->entry[i] = ac->entry[ac->avail];
744                                 ac->entry[ac->avail] = objp;
745                                 return objp;
746                         }
747                 }
748 
749                 /*
750                  * If there are empty slabs on the slabs_free list and we are
751                  * being forced to refill the cache, mark this one !pfmemalloc.
752                  */
753                 n = get_node(cachep, numa_mem_id());
754                 if (!list_empty(&n->slabs_free) && force_refill) {
755                         struct page *page = virt_to_head_page(objp);
756                         ClearPageSlabPfmemalloc(page);
757                         clear_obj_pfmemalloc(&objp);
758                         recheck_pfmemalloc_active(cachep, ac);
759                         return objp;
760                 }
761 
762                 /* No !PFMEMALLOC objects available */
763                 ac->avail++;
764                 objp = NULL;
765         }
766 
767         return objp;
768 }
769 
770 static inline void *ac_get_obj(struct kmem_cache *cachep,
771                         struct array_cache *ac, gfp_t flags, bool force_refill)
772 {
773         void *objp;
774 
775         if (unlikely(sk_memalloc_socks()))
776                 objp = __ac_get_obj(cachep, ac, flags, force_refill);
777         else
778                 objp = ac->entry[--ac->avail];
779 
780         return objp;
781 }
782 
783 static noinline void *__ac_put_obj(struct kmem_cache *cachep,
784                         struct array_cache *ac, void *objp)
785 {
786         if (unlikely(pfmemalloc_active)) {
787                 /* Some pfmemalloc slabs exist, check if this is one */
788                 struct page *page = virt_to_head_page(objp);
789                 if (PageSlabPfmemalloc(page))
790                         set_obj_pfmemalloc(&objp);
791         }
792 
793         return objp;
794 }
795 
796 static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
797                                                                 void *objp)
798 {
799         if (unlikely(sk_memalloc_socks()))
800                 objp = __ac_put_obj(cachep, ac, objp);
801 
802         ac->entry[ac->avail++] = objp;
803 }
804 
805 /*
806  * Transfer objects in one arraycache to another.
807  * Locking must be handled by the caller.
808  *
809  * Return the number of entries transferred.
810  */
811 static int transfer_objects(struct array_cache *to,
812                 struct array_cache *from, unsigned int max)
813 {
814         /* Figure out how many entries to transfer */
815         int nr = min3(from->avail, max, to->limit - to->avail);
816 
817         if (!nr)
818                 return 0;
819 
820         memcpy(to->entry + to->avail, from->entry + from->avail -nr,
821                         sizeof(void *) *nr);
822 
823         from->avail -= nr;
824         to->avail += nr;
825         return nr;
826 }
827 
828 #ifndef CONFIG_NUMA
829 
830 #define drain_alien_cache(cachep, alien) do { } while (0)
831 #define reap_alien(cachep, n) do { } while (0)
832 
833 static inline struct alien_cache **alloc_alien_cache(int node,
834                                                 int limit, gfp_t gfp)
835 {
836         return (struct alien_cache **)BAD_ALIEN_MAGIC;
837 }
838 
839 static inline void free_alien_cache(struct alien_cache **ac_ptr)
840 {
841 }
842 
843 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
844 {
845         return 0;
846 }
847 
848 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
849                 gfp_t flags)
850 {
851         return NULL;
852 }
853 
854 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
855                  gfp_t flags, int nodeid)
856 {
857         return NULL;
858 }
859 
860 #else   /* CONFIG_NUMA */
861 
862 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
863 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
864 
865 static struct alien_cache *__alloc_alien_cache(int node, int entries,
866                                                 int batch, gfp_t gfp)
867 {
868         size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache);
869         struct alien_cache *alc = NULL;
870 
871         alc = kmalloc_node(memsize, gfp, node);
872         init_arraycache(&alc->ac, entries, batch);
873         spin_lock_init(&alc->lock);
874         return alc;
875 }
876 
877 static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
878 {
879         struct alien_cache **alc_ptr;
880         size_t memsize = sizeof(void *) * nr_node_ids;
881         int i;
882 
883         if (limit > 1)
884                 limit = 12;
885         alc_ptr = kzalloc_node(memsize, gfp, node);
886         if (!alc_ptr)
887                 return NULL;
888 
889         for_each_node(i) {
890                 if (i == node || !node_online(i))
891                         continue;
892                 alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp);
893                 if (!alc_ptr[i]) {
894                         for (i--; i >= 0; i--)
895                                 kfree(alc_ptr[i]);
896                         kfree(alc_ptr);
897                         return NULL;
898                 }
899         }
900         return alc_ptr;
901 }
902 
903 static void free_alien_cache(struct alien_cache **alc_ptr)
904 {
905         int i;
906 
907         if (!alc_ptr)
908                 return;
909         for_each_node(i)
910             kfree(alc_ptr[i]);
911         kfree(alc_ptr);
912 }
913 
914 static void __drain_alien_cache(struct kmem_cache *cachep,
915                                 struct array_cache *ac, int node,
916                                 struct list_head *list)
917 {
918         struct kmem_cache_node *n = get_node(cachep, node);
919 
920         if (ac->avail) {
921                 spin_lock(&n->list_lock);
922                 /*
923                  * Stuff objects into the remote nodes shared array first.
924                  * That way we could avoid the overhead of putting the objects
925                  * into the free lists and getting them back later.
926                  */
927                 if (n->shared)
928                         transfer_objects(n->shared, ac, ac->limit);
929 
930                 free_block(cachep, ac->entry, ac->avail, node, list);
931                 ac->avail = 0;
932                 spin_unlock(&n->list_lock);
933         }
934 }
935 
936 /*
937  * Called from cache_reap() to regularly drain alien caches round robin.
938  */
939 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
940 {
941         int node = __this_cpu_read(slab_reap_node);
942 
943         if (n->alien) {
944                 struct alien_cache *alc = n->alien[node];
945                 struct array_cache *ac;
946 
947                 if (alc) {
948                         ac = &alc->ac;
949                         if (ac->avail && spin_trylock_irq(&alc->lock)) {
950                                 LIST_HEAD(list);
951 
952                                 __drain_alien_cache(cachep, ac, node, &list);
953                                 spin_unlock_irq(&alc->lock);
954                                 slabs_destroy(cachep, &list);
955                         }
956                 }
957         }
958 }
959 
960 static void drain_alien_cache(struct kmem_cache *cachep,
961                                 struct alien_cache **alien)
962 {
963         int i = 0;
964         struct alien_cache *alc;
965         struct array_cache *ac;
966         unsigned long flags;
967 
968         for_each_online_node(i) {
969                 alc = alien[i];
970                 if (alc) {
971                         LIST_HEAD(list);
972 
973                         ac = &alc->ac;
974                         spin_lock_irqsave(&alc->lock, flags);
975                         __drain_alien_cache(cachep, ac, i, &list);
976                         spin_unlock_irqrestore(&alc->lock, flags);
977                         slabs_destroy(cachep, &list);
978                 }
979         }
980 }
981 
982 static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
983                                 int node, int page_node)
984 {
985         struct kmem_cache_node *n;
986         struct alien_cache *alien = NULL;
987         struct array_cache *ac;
988         LIST_HEAD(list);
989 
990         n = get_node(cachep, node);
991         STATS_INC_NODEFREES(cachep);
992         if (n->alien && n->alien[page_node]) {
993                 alien = n->alien[page_node];
994                 ac = &alien->ac;
995                 spin_lock(&alien->lock);
996                 if (unlikely(ac->avail == ac->limit)) {
997                         STATS_INC_ACOVERFLOW(cachep);
998                         __drain_alien_cache(cachep, ac, page_node, &list);
999                 }
1000                 ac_put_obj(cachep, ac, objp);
1001                 spin_unlock(&alien->lock);
1002                 slabs_destroy(cachep, &list);
1003         } else {
1004                 n = get_node(cachep, page_node);
1005                 spin_lock(&n->list_lock);
1006                 free_block(cachep, &objp, 1, page_node, &list);
1007                 spin_unlock(&n->list_lock);
1008                 slabs_destroy(cachep, &list);
1009         }
1010         return 1;
1011 }
1012 
1013 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1014 {
1015         int page_node = page_to_nid(virt_to_page(objp));
1016         int node = numa_mem_id();
1017         /*
1018          * Make sure we are not freeing a object from another node to the array
1019          * cache on this cpu.
1020          */
1021         if (likely(node == page_node))
1022                 return 0;
1023 
1024         return __cache_free_alien(cachep, objp, node, page_node);
1025 }
1026 #endif
1027 
1028 /*
1029  * Allocates and initializes node for a node on each slab cache, used for
1030  * either memory or cpu hotplug.  If memory is being hot-added, the kmem_cache_node
1031  * will be allocated off-node since memory is not yet online for the new node.
1032  * When hotplugging memory or a cpu, existing node are not replaced if
1033  * already in use.
1034  *
1035  * Must hold slab_mutex.
1036  */
1037 static int init_cache_node_node(int node)
1038 {
1039         struct kmem_cache *cachep;
1040         struct kmem_cache_node *n;
1041         const size_t memsize = sizeof(struct kmem_cache_node);
1042 
1043         list_for_each_entry(cachep, &slab_caches, list) {
1044                 /*
1045                  * Set up the kmem_cache_node for cpu before we can
1046                  * begin anything. Make sure some other cpu on this
1047                  * node has not already allocated this
1048                  */
1049                 n = get_node(cachep, node);
1050                 if (!n) {
1051                         n = kmalloc_node(memsize, GFP_KERNEL, node);
1052                         if (!n)
1053                                 return -ENOMEM;
1054                         kmem_cache_node_init(n);
1055                         n->next_reap = jiffies + REAPTIMEOUT_NODE +
1056                             ((unsigned long)cachep) % REAPTIMEOUT_NODE;
1057 
1058                         /*
1059                          * The kmem_cache_nodes don't come and go as CPUs
1060                          * come and go.  slab_mutex is sufficient
1061                          * protection here.
1062                          */
1063                         cachep->node[node] = n;
1064                 }
1065 
1066                 spin_lock_irq(&n->list_lock);
1067                 n->free_limit =
1068                         (1 + nr_cpus_node(node)) *
1069                         cachep->batchcount + cachep->num;
1070                 spin_unlock_irq(&n->list_lock);
1071         }
1072         return 0;
1073 }
1074 
1075 static inline int slabs_tofree(struct kmem_cache *cachep,
1076                                                 struct kmem_cache_node *n)
1077 {
1078         return (n->free_objects + cachep->num - 1) / cachep->num;
1079 }
1080 
1081 static void cpuup_canceled(long cpu)
1082 {
1083         struct kmem_cache *cachep;
1084         struct kmem_cache_node *n = NULL;
1085         int node = cpu_to_mem(cpu);
1086         const struct cpumask *mask = cpumask_of_node(node);
1087 
1088         list_for_each_entry(cachep, &slab_caches, list) {
1089                 struct array_cache *nc;
1090                 struct array_cache *shared;
1091                 struct alien_cache **alien;
1092                 LIST_HEAD(list);
1093 
1094                 n = get_node(cachep, node);
1095                 if (!n)
1096                         continue;
1097 
1098                 spin_lock_irq(&n->list_lock);
1099 
1100                 /* Free limit for this kmem_cache_node */
1101                 n->free_limit -= cachep->batchcount;
1102 
1103                 /* cpu is dead; no one can alloc from it. */
1104                 nc = per_cpu_ptr(cachep->cpu_cache, cpu);
1105                 if (nc) {
1106                         free_block(cachep, nc->entry, nc->avail, node, &list);
1107                         nc->avail = 0;
1108                 }
1109 
1110                 if (!cpumask_empty(mask)) {
1111                         spin_unlock_irq(&n->list_lock);
1112                         goto free_slab;
1113                 }
1114 
1115                 shared = n->shared;
1116                 if (shared) {
1117                         free_block(cachep, shared->entry,
1118                                    shared->avail, node, &list);
1119                         n->shared = NULL;
1120                 }
1121 
1122                 alien = n->alien;
1123                 n->alien = NULL;
1124 
1125                 spin_unlock_irq(&n->list_lock);
1126 
1127                 kfree(shared);
1128                 if (alien) {
1129                         drain_alien_cache(cachep, alien);
1130                         free_alien_cache(alien);
1131                 }
1132 
1133 free_slab:
1134                 slabs_destroy(cachep, &list);
1135         }
1136         /*
1137          * In the previous loop, all the objects were freed to
1138          * the respective cache's slabs,  now we can go ahead and
1139          * shrink each nodelist to its limit.
1140          */
1141         list_for_each_entry(cachep, &slab_caches, list) {
1142                 n = get_node(cachep, node);
1143                 if (!n)
1144                         continue;
1145                 drain_freelist(cachep, n, slabs_tofree(cachep, n));
1146         }
1147 }
1148 
1149 static int cpuup_prepare(long cpu)
1150 {
1151         struct kmem_cache *cachep;
1152         struct kmem_cache_node *n = NULL;
1153         int node = cpu_to_mem(cpu);
1154         int err;
1155 
1156         /*
1157          * We need to do this right in the beginning since
1158          * alloc_arraycache's are going to use this list.
1159          * kmalloc_node allows us to add the slab to the right
1160          * kmem_cache_node and not this cpu's kmem_cache_node
1161          */
1162         err = init_cache_node_node(node);
1163         if (err < 0)
1164                 goto bad;
1165 
1166         /*
1167          * Now we can go ahead with allocating the shared arrays and
1168          * array caches
1169          */
1170         list_for_each_entry(cachep, &slab_caches, list) {
1171                 struct array_cache *shared = NULL;
1172                 struct alien_cache **alien = NULL;
1173 
1174                 if (cachep->shared) {
1175                         shared = alloc_arraycache(node,
1176                                 cachep->shared * cachep->batchcount,
1177                                 0xbaadf00d, GFP_KERNEL);
1178                         if (!shared)
1179                                 goto bad;
1180                 }
1181                 if (use_alien_caches) {
1182                         alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
1183                         if (!alien) {
1184                                 kfree(shared);
1185                                 goto bad;
1186                         }
1187                 }
1188                 n = get_node(cachep, node);
1189                 BUG_ON(!n);
1190 
1191                 spin_lock_irq(&n->list_lock);
1192                 if (!n->shared) {
1193                         /*
1194                          * We are serialised from CPU_DEAD or
1195                          * CPU_UP_CANCELLED by the cpucontrol lock
1196                          */
1197                         n->shared = shared;
1198                         shared = NULL;
1199                 }
1200 #ifdef CONFIG_NUMA
1201                 if (!n->alien) {
1202                         n->alien = alien;
1203                         alien = NULL;
1204                 }
1205 #endif
1206                 spin_unlock_irq(&n->list_lock);
1207                 kfree(shared);
1208                 free_alien_cache(alien);
1209         }
1210 
1211         return 0;
1212 bad:
1213         cpuup_canceled(cpu);
1214         return -ENOMEM;
1215 }
1216 
1217 static int cpuup_callback(struct notifier_block *nfb,
1218                                     unsigned long action, void *hcpu)
1219 {
1220         long cpu = (long)hcpu;
1221         int err = 0;
1222 
1223         switch (action) {
1224         case CPU_UP_PREPARE:
1225         case CPU_UP_PREPARE_FROZEN:
1226                 mutex_lock(&slab_mutex);
1227                 err = cpuup_prepare(cpu);
1228                 mutex_unlock(&slab_mutex);
1229                 break;
1230         case CPU_ONLINE:
1231         case CPU_ONLINE_FROZEN:
1232                 start_cpu_timer(cpu);
1233                 break;
1234 #ifdef CONFIG_HOTPLUG_CPU
1235         case CPU_DOWN_PREPARE:
1236         case CPU_DOWN_PREPARE_FROZEN:
1237                 /*
1238                  * Shutdown cache reaper. Note that the slab_mutex is
1239                  * held so that if cache_reap() is invoked it cannot do
1240                  * anything expensive but will only modify reap_work
1241                  * and reschedule the timer.
1242                 */
1243                 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
1244                 /* Now the cache_reaper is guaranteed to be not running. */
1245                 per_cpu(slab_reap_work, cpu).work.func = NULL;
1246                 break;
1247         case CPU_DOWN_FAILED:
1248         case CPU_DOWN_FAILED_FROZEN:
1249                 start_cpu_timer(cpu);
1250                 break;
1251         case CPU_DEAD:
1252         case CPU_DEAD_FROZEN:
1253                 /*
1254                  * Even if all the cpus of a node are down, we don't free the
1255                  * kmem_cache_node of any cache. This to avoid a race between
1256                  * cpu_down, and a kmalloc allocation from another cpu for
1257                  * memory from the node of the cpu going down.  The node
1258                  * structure is usually allocated from kmem_cache_create() and
1259                  * gets destroyed at kmem_cache_destroy().
1260                  */
1261                 /* fall through */
1262 #endif
1263         case CPU_UP_CANCELED:
1264         case CPU_UP_CANCELED_FROZEN:
1265                 mutex_lock(&slab_mutex);
1266                 cpuup_canceled(cpu);
1267                 mutex_unlock(&slab_mutex);
1268                 break;
1269         }
1270         return notifier_from_errno(err);
1271 }
1272 
1273 static struct notifier_block cpucache_notifier = {
1274         &cpuup_callback, NULL, 0
1275 };
1276 
1277 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1278 /*
1279  * Drains freelist for a node on each slab cache, used for memory hot-remove.
1280  * Returns -EBUSY if all objects cannot be drained so that the node is not
1281  * removed.
1282  *
1283  * Must hold slab_mutex.
1284  */
1285 static int __meminit drain_cache_node_node(int node)
1286 {
1287         struct kmem_cache *cachep;
1288         int ret = 0;
1289 
1290         list_for_each_entry(cachep, &slab_caches, list) {
1291                 struct kmem_cache_node *n;
1292 
1293                 n = get_node(cachep, node);
1294                 if (!n)
1295                         continue;
1296 
1297                 drain_freelist(cachep, n, slabs_tofree(cachep, n));
1298 
1299                 if (!list_empty(&n->slabs_full) ||
1300                     !list_empty(&n->slabs_partial)) {
1301                         ret = -EBUSY;
1302                         break;
1303                 }
1304         }
1305         return ret;
1306 }
1307 
1308 static int __meminit slab_memory_callback(struct notifier_block *self,
1309                                         unsigned long action, void *arg)
1310 {
1311         struct memory_notify *mnb = arg;
1312         int ret = 0;
1313         int nid;
1314 
1315         nid = mnb->status_change_nid;
1316         if (nid < 0)
1317                 goto out;
1318 
1319         switch (action) {
1320         case MEM_GOING_ONLINE:
1321                 mutex_lock(&slab_mutex);
1322                 ret = init_cache_node_node(nid);
1323                 mutex_unlock(&slab_mutex);
1324                 break;
1325         case MEM_GOING_OFFLINE:
1326                 mutex_lock(&slab_mutex);
1327                 ret = drain_cache_node_node(nid);
1328                 mutex_unlock(&slab_mutex);
1329                 break;
1330         case MEM_ONLINE:
1331         case MEM_OFFLINE:
1332         case MEM_CANCEL_ONLINE:
1333         case MEM_CANCEL_OFFLINE:
1334                 break;
1335         }
1336 out:
1337         return notifier_from_errno(ret);
1338 }
1339 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1340 
1341 /*
1342  * swap the static kmem_cache_node with kmalloced memory
1343  */
1344 static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list,
1345                                 int nodeid)
1346 {
1347         struct kmem_cache_node *ptr;
1348 
1349         ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid);
1350         BUG_ON(!ptr);
1351 
1352         memcpy(ptr, list, sizeof(struct kmem_cache_node));
1353         /*
1354          * Do not assume that spinlocks can be initialized via memcpy:
1355          */
1356         spin_lock_init(&ptr->list_lock);
1357 
1358         MAKE_ALL_LISTS(cachep, ptr, nodeid);
1359         cachep->node[nodeid] = ptr;
1360 }
1361 
1362 /*
1363  * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1364  * size of kmem_cache_node.
1365  */
1366 static void __init set_up_node(struct kmem_cache *cachep, int index)
1367 {
1368         int node;
1369 
1370         for_each_online_node(node) {
1371                 cachep->node[node] = &init_kmem_cache_node[index + node];
1372                 cachep->node[node]->next_reap = jiffies +
1373                     REAPTIMEOUT_NODE +
1374                     ((unsigned long)cachep) % REAPTIMEOUT_NODE;
1375         }
1376 }
1377 
1378 /*
1379  * Initialisation.  Called after the page allocator have been initialised and
1380  * before smp_init().
1381  */
1382 void __init kmem_cache_init(void)
1383 {
1384         int i;
1385 
1386         BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) <
1387                                         sizeof(struct rcu_head));
1388         kmem_cache = &kmem_cache_boot;
1389 
1390         if (num_possible_nodes() == 1)
1391                 use_alien_caches = 0;
1392 
1393         for (i = 0; i < NUM_INIT_LISTS; i++)
1394                 kmem_cache_node_init(&init_kmem_cache_node[i]);
1395 
1396         /*
1397          * Fragmentation resistance on low memory - only use bigger
1398          * page orders on machines with more than 32MB of memory if
1399          * not overridden on the command line.
1400          */
1401         if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
1402                 slab_max_order = SLAB_MAX_ORDER_HI;
1403 
1404         /* Bootstrap is tricky, because several objects are allocated
1405          * from caches that do not exist yet:
1406          * 1) initialize the kmem_cache cache: it contains the struct
1407          *    kmem_cache structures of all caches, except kmem_cache itself:
1408          *    kmem_cache is statically allocated.
1409          *    Initially an __init data area is used for the head array and the
1410          *    kmem_cache_node structures, it's replaced with a kmalloc allocated
1411          *    array at the end of the bootstrap.
1412          * 2) Create the first kmalloc cache.
1413          *    The struct kmem_cache for the new cache is allocated normally.
1414          *    An __init data area is used for the head array.
1415          * 3) Create the remaining kmalloc caches, with minimally sized
1416          *    head arrays.
1417          * 4) Replace the __init data head arrays for kmem_cache and the first
1418          *    kmalloc cache with kmalloc allocated arrays.
1419          * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1420          *    the other cache's with kmalloc allocated memory.
1421          * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1422          */
1423 
1424         /* 1) create the kmem_cache */
1425 
1426         /*
1427          * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1428          */
1429         create_boot_cache(kmem_cache, "kmem_cache",
1430                 offsetof(struct kmem_cache, node) +
1431                                   nr_node_ids * sizeof(struct kmem_cache_node *),
1432                                   SLAB_HWCACHE_ALIGN);
1433         list_add(&kmem_cache->list, &slab_caches);
1434         slab_state = PARTIAL;
1435 
1436         /*
1437          * Initialize the caches that provide memory for the  kmem_cache_node
1438          * structures first.  Without this, further allocations will bug.
1439          */
1440         kmalloc_caches[INDEX_NODE] = create_kmalloc_cache("kmalloc-node",
1441                                 kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS);
1442         slab_state = PARTIAL_NODE;
1443 
1444         slab_early_init = 0;
1445 
1446         /* 5) Replace the bootstrap kmem_cache_node */
1447         {
1448                 int nid;
1449 
1450                 for_each_online_node(nid) {
1451                         init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid);
1452 
1453                         init_list(kmalloc_caches[INDEX_NODE],
1454                                           &init_kmem_cache_node[SIZE_NODE + nid], nid);
1455                 }
1456         }
1457 
1458         create_kmalloc_caches(ARCH_KMALLOC_FLAGS);
1459 }
1460 
1461 void __init kmem_cache_init_late(void)
1462 {
1463         struct kmem_cache *cachep;
1464 
1465         slab_state = UP;
1466 
1467         /* 6) resize the head arrays to their final sizes */
1468         mutex_lock(&slab_mutex);
1469         list_for_each_entry(cachep, &slab_caches, list)
1470                 if (enable_cpucache(cachep, GFP_NOWAIT))
1471                         BUG();
1472         mutex_unlock(&slab_mutex);
1473 
1474         /* Done! */
1475         slab_state = FULL;
1476 
1477         /*
1478          * Register a cpu startup notifier callback that initializes
1479          * cpu_cache_get for all new cpus
1480          */
1481         register_cpu_notifier(&cpucache_notifier);
1482 
1483 #ifdef CONFIG_NUMA
1484         /*
1485          * Register a memory hotplug callback that initializes and frees
1486          * node.
1487          */
1488         hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
1489 #endif
1490 
1491         /*
1492          * The reap timers are started later, with a module init call: That part
1493          * of the kernel is not yet operational.
1494          */
1495 }
1496 
1497 static int __init cpucache_init(void)
1498 {
1499         int cpu;
1500 
1501         /*
1502          * Register the timers that return unneeded pages to the page allocator
1503          */
1504         for_each_online_cpu(cpu)
1505                 start_cpu_timer(cpu);
1506 
1507         /* Done! */
1508         slab_state = FULL;
1509         return 0;
1510 }
1511 __initcall(cpucache_init);
1512 
1513 static noinline void
1514 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
1515 {
1516 #if DEBUG
1517         struct kmem_cache_node *n;
1518         struct page *page;
1519         unsigned long flags;
1520         int node;
1521         static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
1522                                       DEFAULT_RATELIMIT_BURST);
1523 
1524         if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs))
1525                 return;
1526 
1527         printk(KERN_WARNING
1528                 "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
1529                 nodeid, gfpflags);
1530         printk(KERN_WARNING "  cache: %s, object size: %d, order: %d\n",
1531                 cachep->name, cachep->size, cachep->gfporder);
1532 
1533         for_each_kmem_cache_node(cachep, node, n) {
1534                 unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
1535                 unsigned long active_slabs = 0, num_slabs = 0;
1536 
1537                 spin_lock_irqsave(&n->list_lock, flags);
1538                 list_for_each_entry(page, &n->slabs_full, lru) {
1539                         active_objs += cachep->num;
1540                         active_slabs++;
1541                 }
1542                 list_for_each_entry(page, &n->slabs_partial, lru) {
1543                         active_objs += page->active;
1544                         active_slabs++;
1545                 }
1546                 list_for_each_entry(page, &n->slabs_free, lru)
1547                         num_slabs++;
1548 
1549                 free_objects += n->free_objects;
1550                 spin_unlock_irqrestore(&n->list_lock, flags);
1551 
1552                 num_slabs += active_slabs;
1553                 num_objs = num_slabs * cachep->num;
1554                 printk(KERN_WARNING
1555                         "  node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
1556                         node, active_slabs, num_slabs, active_objs, num_objs,
1557                         free_objects);
1558         }
1559 #endif
1560 }
1561 
1562 /*
1563  * Interface to system's page allocator. No need to hold the
1564  * kmem_cache_node ->list_lock.
1565  *
1566  * If we requested dmaable memory, we will get it. Even if we
1567  * did not request dmaable memory, we might get it, but that
1568  * would be relatively rare and ignorable.
1569  */
1570 static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
1571                                                                 int nodeid)
1572 {
1573         struct page *page;
1574         int nr_pages;
1575 
1576         flags |= cachep->allocflags;
1577         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1578                 flags |= __GFP_RECLAIMABLE;
1579 
1580         if (memcg_charge_slab(cachep, flags, cachep->gfporder))
1581                 return NULL;
1582 
1583         page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1584         if (!page) {
1585                 memcg_uncharge_slab(cachep, cachep->gfporder);
1586                 slab_out_of_memory(cachep, flags, nodeid);
1587                 return NULL;
1588         }
1589 
1590         /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1591         if (unlikely(page->pfmemalloc))
1592                 pfmemalloc_active = true;
1593 
1594         nr_pages = (1 << cachep->gfporder);
1595         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1596                 add_zone_page_state(page_zone(page),
1597                         NR_SLAB_RECLAIMABLE, nr_pages);
1598         else
1599                 add_zone_page_state(page_zone(page),
1600                         NR_SLAB_UNRECLAIMABLE, nr_pages);
1601         __SetPageSlab(page);
1602         if (page->pfmemalloc)
1603                 SetPageSlabPfmemalloc(page);
1604 
1605         if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1606                 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1607 
1608                 if (cachep->ctor)
1609                         kmemcheck_mark_uninitialized_pages(page, nr_pages);
1610                 else
1611                         kmemcheck_mark_unallocated_pages(page, nr_pages);
1612         }
1613 
1614         return page;
1615 }
1616 
1617 /*
1618  * Interface to system's page release.
1619  */
1620 static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
1621 {
1622         const unsigned long nr_freed = (1 << cachep->gfporder);
1623 
1624         kmemcheck_free_shadow(page, cachep->gfporder);
1625 
1626         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1627                 sub_zone_page_state(page_zone(page),
1628                                 NR_SLAB_RECLAIMABLE, nr_freed);
1629         else
1630                 sub_zone_page_state(page_zone(page),
1631                                 NR_SLAB_UNRECLAIMABLE, nr_freed);
1632 
1633         BUG_ON(!PageSlab(page));
1634         __ClearPageSlabPfmemalloc(page);
1635         __ClearPageSlab(page);
1636         page_mapcount_reset(page);
1637         page->mapping = NULL;
1638 
1639         if (current->reclaim_state)
1640                 current->reclaim_state->reclaimed_slab += nr_freed;
1641         __free_pages(page, cachep->gfporder);
1642         memcg_uncharge_slab(cachep, cachep->gfporder);
1643 }
1644 
1645 static void kmem_rcu_free(struct rcu_head *head)
1646 {
1647         struct kmem_cache *cachep;
1648         struct page *page;
1649 
1650         page = container_of(head, struct page, rcu_head);
1651         cachep = page->slab_cache;
1652 
1653         kmem_freepages(cachep, page);
1654 }
1655 
1656 #if DEBUG
1657 
1658 #ifdef CONFIG_DEBUG_PAGEALLOC
1659 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1660                             unsigned long caller)
1661 {
1662         int size = cachep->object_size;
1663 
1664         addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1665 
1666         if (size < 5 * sizeof(unsigned long))
1667                 return;
1668 
1669         *addr++ = 0x12345678;
1670         *addr++ = caller;
1671         *addr++ = smp_processor_id();
1672         size -= 3 * sizeof(unsigned long);
1673         {
1674                 unsigned long *sptr = &caller;
1675                 unsigned long svalue;
1676 
1677                 while (!kstack_end(sptr)) {
1678                         svalue = *sptr++;
1679                         if (kernel_text_address(svalue)) {
1680                                 *addr++ = svalue;
1681                                 size -= sizeof(unsigned long);
1682                                 if (size <= sizeof(unsigned long))
1683                                         break;
1684                         }
1685                 }
1686 
1687         }
1688         *addr++ = 0x87654321;
1689 }
1690 #endif
1691 
1692 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1693 {
1694         int size = cachep->object_size;
1695         addr = &((char *)addr)[obj_offset(cachep)];
1696 
1697         memset(addr, val, size);
1698         *(unsigned char *)(addr + size - 1) = POISON_END;
1699 }
1700 
1701 static void dump_line(char *data, int offset, int limit)
1702 {
1703         int i;
1704         unsigned char error = 0;
1705         int bad_count = 0;
1706 
1707         printk(KERN_ERR "%03x: ", offset);
1708         for (i = 0; i < limit; i++) {
1709                 if (data[offset + i] != POISON_FREE) {
1710                         error = data[offset + i];
1711                         bad_count++;
1712                 }
1713         }
1714         print_hex_dump(KERN_CONT, "", 0, 16, 1,
1715                         &data[offset], limit, 1);
1716 
1717         if (bad_count == 1) {
1718                 error ^= POISON_FREE;
1719                 if (!(error & (error - 1))) {
1720                         printk(KERN_ERR "Single bit error detected. Probably "
1721                                         "bad RAM.\n");
1722 #ifdef CONFIG_X86
1723                         printk(KERN_ERR "Run memtest86+ or a similar memory "
1724                                         "test tool.\n");
1725 #else
1726                         printk(KERN_ERR "Run a memory test tool.\n");
1727 #endif
1728                 }
1729         }
1730 }
1731 #endif
1732 
1733 #if DEBUG
1734 
1735 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1736 {
1737         int i, size;
1738         char *realobj;
1739 
1740         if (cachep->flags & SLAB_RED_ZONE) {
1741                 printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n",
1742                         *dbg_redzone1(cachep, objp),
1743                         *dbg_redzone2(cachep, objp));
1744         }
1745 
1746         if (cachep->flags & SLAB_STORE_USER) {
1747                 printk(KERN_ERR "Last user: [<%p>](%pSR)\n",
1748                        *dbg_userword(cachep, objp),
1749                        *dbg_userword(cachep, objp));
1750         }
1751         realobj = (char *)objp + obj_offset(cachep);
1752         size = cachep->object_size;
1753         for (i = 0; i < size && lines; i += 16, lines--) {
1754                 int limit;
1755                 limit = 16;
1756                 if (i + limit > size)
1757                         limit = size - i;
1758                 dump_line(realobj, i, limit);
1759         }
1760 }
1761 
1762 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1763 {
1764         char *realobj;
1765         int size, i;
1766         int lines = 0;
1767 
1768         realobj = (char *)objp + obj_offset(cachep);
1769         size = cachep->object_size;
1770 
1771         for (i = 0; i < size; i++) {
1772                 char exp = POISON_FREE;
1773                 if (i == size - 1)
1774                         exp = POISON_END;
1775                 if (realobj[i] != exp) {
1776                         int limit;
1777                         /* Mismatch ! */
1778                         /* Print header */
1779                         if (lines == 0) {
1780                                 printk(KERN_ERR
1781                                         "Slab corruption (%s): %s start=%p, len=%d\n",
1782                                         print_tainted(), cachep->name, realobj, size);
1783                                 print_objinfo(cachep, objp, 0);
1784                         }
1785                         /* Hexdump the affected line */
1786                         i = (i / 16) * 16;
1787                         limit = 16;
1788                         if (i + limit > size)
1789                                 limit = size - i;
1790                         dump_line(realobj, i, limit);
1791                         i += 16;
1792                         lines++;
1793                         /* Limit to 5 lines */
1794                         if (lines > 5)
1795                                 break;
1796                 }
1797         }
1798         if (lines != 0) {
1799                 /* Print some data about the neighboring objects, if they
1800                  * exist:
1801                  */
1802                 struct page *page = virt_to_head_page(objp);
1803                 unsigned int objnr;
1804 
1805                 objnr = obj_to_index(cachep, page, objp);
1806                 if (objnr) {
1807                         objp = index_to_obj(cachep, page, objnr - 1);
1808                         realobj = (char *)objp + obj_offset(cachep);
1809                         printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1810                                realobj, size);
1811                         print_objinfo(cachep, objp, 2);
1812                 }
1813                 if (objnr + 1 < cachep->num) {
1814                         objp = index_to_obj(cachep, page, objnr + 1);
1815                         realobj = (char *)objp + obj_offset(cachep);
1816                         printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1817                                realobj, size);
1818                         print_objinfo(cachep, objp, 2);
1819                 }
1820         }
1821 }
1822 #endif
1823 
1824 #if DEBUG
1825 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1826                                                 struct page *page)
1827 {
1828         int i;
1829         for (i = 0; i < cachep->num; i++) {
1830                 void *objp = index_to_obj(cachep, page, i);
1831 
1832                 if (cachep->flags & SLAB_POISON) {
1833 #ifdef CONFIG_DEBUG_PAGEALLOC
1834                         if (cachep->size % PAGE_SIZE == 0 &&
1835                                         OFF_SLAB(cachep))
1836                                 kernel_map_pages(virt_to_page(objp),
1837                                         cachep->size / PAGE_SIZE, 1);
1838                         else
1839                                 check_poison_obj(cachep, objp);
1840 #else
1841                         check_poison_obj(cachep, objp);
1842 #endif
1843                 }
1844                 if (cachep->flags & SLAB_RED_ZONE) {
1845                         if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1846                                 slab_error(cachep, "start of a freed object "
1847                                            "was overwritten");
1848                         if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1849                                 slab_error(cachep, "end of a freed object "
1850                                            "was overwritten");
1851                 }
1852         }
1853 }
1854 #else
1855 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1856                                                 struct page *page)
1857 {
1858 }
1859 #endif
1860 
1861 /**
1862  * slab_destroy - destroy and release all objects in a slab
1863  * @cachep: cache pointer being destroyed
1864  * @page: page pointer being destroyed
1865  *
1866  * Destroy all the objs in a slab page, and release the mem back to the system.
1867  * Before calling the slab page must have been unlinked from the cache. The
1868  * kmem_cache_node ->list_lock is not held/needed.
1869  */
1870 static void slab_destroy(struct kmem_cache *cachep, struct page *page)
1871 {
1872         void *freelist;
1873 
1874         freelist = page->freelist;
1875         slab_destroy_debugcheck(cachep, page);
1876         if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
1877                 struct rcu_head *head;
1878 
1879                 /*
1880                  * RCU free overloads the RCU head over the LRU.
1881                  * slab_page has been overloeaded over the LRU,
1882                  * however it is not used from now on so that
1883                  * we can use it safely.
1884                  */
1885                 head = (void *)&page->rcu_head;
1886                 call_rcu(head, kmem_rcu_free);
1887 
1888         } else {
1889                 kmem_freepages(cachep, page);
1890         }
1891 
1892         /*
1893          * From now on, we don't use freelist
1894          * although actual page can be freed in rcu context
1895          */
1896         if (OFF_SLAB(cachep))
1897                 kmem_cache_free(cachep->freelist_cache, freelist);
1898 }
1899 
1900 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list)
1901 {
1902         struct page *page, *n;
1903 
1904         list_for_each_entry_safe(page, n, list, lru) {
1905                 list_del(&page->lru);
1906                 slab_destroy(cachep, page);
1907         }
1908 }
1909 
1910 /**
1911  * calculate_slab_order - calculate size (page order) of slabs
1912  * @cachep: pointer to the cache that is being created
1913  * @size: size of objects to be created in this cache.
1914  * @align: required alignment for the objects.
1915  * @flags: slab allocation flags
1916  *
1917  * Also calculates the number of objects per slab.
1918  *
1919  * This could be made much more intelligent.  For now, try to avoid using
1920  * high order pages for slabs.  When the gfp() functions are more friendly
1921  * towards high-order requests, this should be changed.
1922  */
1923 static size_t calculate_slab_order(struct kmem_cache *cachep,
1924                         size_t size, size_t align, unsigned long flags)
1925 {
1926         unsigned long offslab_limit;
1927         size_t left_over = 0;
1928         int gfporder;
1929 
1930         for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
1931                 unsigned int num;
1932                 size_t remainder;
1933 
1934                 cache_estimate(gfporder, size, align, flags, &remainder, &num);
1935                 if (!num)
1936                         continue;
1937 
1938                 /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */
1939                 if (num > SLAB_OBJ_MAX_NUM)
1940                         break;
1941 
1942                 if (flags & CFLGS_OFF_SLAB) {
1943                         size_t freelist_size_per_obj = sizeof(freelist_idx_t);
1944                         /*
1945                          * Max number of objs-per-slab for caches which
1946                          * use off-slab slabs. Needed to avoid a possible
1947                          * looping condition in cache_grow().
1948                          */
1949                         if (IS_ENABLED(CONFIG_DEBUG_SLAB_LEAK))
1950                                 freelist_size_per_obj += sizeof(char);
1951                         offslab_limit = size;
1952                         offslab_limit /= freelist_size_per_obj;
1953 
1954                         if (num > offslab_limit)
1955                                 break;
1956                 }
1957 
1958                 /* Found something acceptable - save it away */
1959                 cachep->num = num;
1960                 cachep->gfporder = gfporder;
1961                 left_over = remainder;
1962 
1963                 /*
1964                  * A VFS-reclaimable slab tends to have most allocations
1965                  * as GFP_NOFS and we really don't want to have to be allocating
1966                  * higher-order pages when we are unable to shrink dcache.
1967                  */
1968                 if (flags & SLAB_RECLAIM_ACCOUNT)
1969                         break;
1970 
1971                 /*
1972                  * Large number of objects is good, but very large slabs are
1973                  * currently bad for the gfp()s.
1974                  */
1975                 if (gfporder >= slab_max_order)
1976                         break;
1977 
1978                 /*
1979                  * Acceptable internal fragmentation?
1980                  */
1981                 if (left_over * 8 <= (PAGE_SIZE << gfporder))
1982                         break;
1983         }
1984         return left_over;
1985 }
1986 
1987 static struct array_cache __percpu *alloc_kmem_cache_cpus(
1988                 struct kmem_cache *cachep, int entries, int batchcount)
1989 {
1990         int cpu;
1991         size_t size;
1992         struct array_cache __percpu *cpu_cache;
1993 
1994         size = sizeof(void *) * entries + sizeof(struct array_cache);
1995         cpu_cache = __alloc_percpu(size, sizeof(void *));
1996 
1997         if (!cpu_cache)
1998                 return NULL;
1999 
2000         for_each_possible_cpu(cpu) {
2001                 init_arraycache(per_cpu_ptr(cpu_cache, cpu),
2002                                 entries, batchcount);
2003         }
2004 
2005         return cpu_cache;
2006 }
2007 
2008 static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
2009 {
2010         if (slab_state >= FULL)
2011                 return enable_cpucache(cachep, gfp);
2012 
2013         cachep->cpu_cache = alloc_kmem_cache_cpus(cachep, 1, 1);
2014         if (!cachep->cpu_cache)
2015                 return 1;
2016 
2017         if (slab_state == DOWN) {
2018                 /* Creation of first cache (kmem_cache). */
2019                 set_up_node(kmem_cache, CACHE_CACHE);
2020         } else if (slab_state == PARTIAL) {
2021                 /* For kmem_cache_node */
2022                 set_up_node(cachep, SIZE_NODE);
2023         } else {
2024                 int node;
2025 
2026                 for_each_online_node(node) {
2027                         cachep->node[node] = kmalloc_node(
2028                                 sizeof(struct kmem_cache_node), gfp, node);
2029                         BUG_ON(!cachep->node[node]);
2030                         kmem_cache_node_init(cachep->node[node]);
2031                 }
2032         }
2033 
2034         cachep->node[numa_mem_id()]->next_reap =
2035                         jiffies + REAPTIMEOUT_NODE +
2036                         ((unsigned long)cachep) % REAPTIMEOUT_NODE;
2037 
2038         cpu_cache_get(cachep)->avail = 0;
2039         cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
2040         cpu_cache_get(cachep)->batchcount = 1;
2041         cpu_cache_get(cachep)->touched = 0;
2042         cachep->batchcount = 1;
2043         cachep->limit = BOOT_CPUCACHE_ENTRIES;
2044         return 0;
2045 }
2046 
2047 unsigned long kmem_cache_flags(unsigned long object_size,
2048         unsigned long flags, const char *name,
2049         void (*ctor)(void *))
2050 {
2051         return flags;
2052 }
2053 
2054 struct kmem_cache *
2055 __kmem_cache_alias(const char *name, size_t size, size_t align,
2056                    unsigned long flags, void (*ctor)(void *))
2057 {
2058         struct kmem_cache *cachep;
2059 
2060         cachep = find_mergeable(size, align, flags, name, ctor);
2061         if (cachep) {
2062                 cachep->refcount++;
2063 
2064                 /*
2065                  * Adjust the object sizes so that we clear
2066                  * the complete object on kzalloc.
2067                  */
2068                 cachep->object_size = max_t(int, cachep->object_size, size);
2069         }
2070         return cachep;
2071 }
2072 
2073 /**
2074  * __kmem_cache_create - Create a cache.
2075  * @cachep: cache management descriptor
2076  * @flags: SLAB flags
2077  *
2078  * Returns a ptr to the cache on success, NULL on failure.
2079  * Cannot be called within a int, but can be interrupted.
2080  * The @ctor is run when new pages are allocated by the cache.
2081  *
2082  * The flags are
2083  *
2084  * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2085  * to catch references to uninitialised memory.
2086  *
2087  * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2088  * for buffer overruns.
2089  *
2090  * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2091  * cacheline.  This can be beneficial if you're counting cycles as closely
2092  * as davem.
2093  */
2094 int
2095 __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
2096 {
2097         size_t left_over, freelist_size;
2098         size_t ralign = BYTES_PER_WORD;
2099         gfp_t gfp;
2100         int err;
2101         size_t size = cachep->size;
2102 
2103 #if DEBUG
2104 #if FORCED_DEBUG
2105         /*
2106          * Enable redzoning and last user accounting, except for caches with
2107          * large objects, if the increased size would increase the object size
2108          * above the next power of two: caches with object sizes just above a
2109          * power of two have a significant amount of internal fragmentation.
2110          */
2111         if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2112                                                 2 * sizeof(unsigned long long)))
2113                 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2114         if (!(flags & SLAB_DESTROY_BY_RCU))
2115                 flags |= SLAB_POISON;
2116 #endif
2117         if (flags & SLAB_DESTROY_BY_RCU)
2118                 BUG_ON(flags & SLAB_POISON);
2119 #endif
2120 
2121         /*
2122          * Check that size is in terms of words.  This is needed to avoid
2123          * unaligned accesses for some archs when redzoning is used, and makes
2124          * sure any on-slab bufctl's are also correctly aligned.
2125          */
2126         if (size & (BYTES_PER_WORD - 1)) {
2127                 size += (BYTES_PER_WORD - 1);
2128                 size &= ~(BYTES_PER_WORD - 1);
2129         }
2130 
2131         if (flags & SLAB_RED_ZONE) {
2132                 ralign = REDZONE_ALIGN;
2133                 /* If redzoning, ensure that the second redzone is suitably
2134                  * aligned, by adjusting the object size accordingly. */
2135                 size += REDZONE_ALIGN - 1;
2136                 size &= ~(REDZONE_ALIGN - 1);
2137         }
2138 
2139         /* 3) caller mandated alignment */
2140         if (ralign < cachep->align) {
2141                 ralign = cachep->align;
2142         }
2143         /* disable debug if necessary */
2144         if (ralign > __alignof__(unsigned long long))
2145                 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2146         /*
2147          * 4) Store it.
2148          */
2149         cachep->align = ralign;
2150 
2151         if (slab_is_available())
2152                 gfp = GFP_KERNEL;
2153         else
2154                 gfp = GFP_NOWAIT;
2155 
2156 #if DEBUG
2157 
2158         /*
2159          * Both debugging options require word-alignment which is calculated
2160          * into align above.
2161          */
2162         if (flags & SLAB_RED_ZONE) {
2163                 /* add space for red zone words */
2164                 cachep->obj_offset += sizeof(unsigned long long);
2165                 size += 2 * sizeof(unsigned long long);
2166         }
2167         if (flags & SLAB_STORE_USER) {
2168                 /* user store requires one word storage behind the end of
2169                  * the real object. But if the second red zone needs to be
2170                  * aligned to 64 bits, we must allow that much space.
2171                  */
2172                 if (flags & SLAB_RED_ZONE)
2173                         size += REDZONE_ALIGN;
2174                 else
2175                         size += BYTES_PER_WORD;
2176         }
2177 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
2178         if (size >= kmalloc_size(INDEX_NODE + 1)
2179             && cachep->object_size > cache_line_size()
2180             && ALIGN(size, cachep->align) < PAGE_SIZE) {
2181                 cachep->obj_offset += PAGE_SIZE - ALIGN(size, cachep->align);
2182                 size = PAGE_SIZE;
2183         }
2184 #endif
2185 #endif
2186 
2187         /*
2188          * Determine if the slab management is 'on' or 'off' slab.
2189          * (bootstrapping cannot cope with offslab caches so don't do
2190          * it too early on. Always use on-slab management when
2191          * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
2192          */
2193         if ((size >= (PAGE_SIZE >> 5)) && !slab_early_init &&
2194             !(flags & SLAB_NOLEAKTRACE))
2195                 /*
2196                  * Size is large, assume best to place the slab management obj
2197                  * off-slab (should allow better packing of objs).
2198                  */
2199                 flags |= CFLGS_OFF_SLAB;
2200 
2201         size = ALIGN(size, cachep->align);
2202         /*
2203          * We should restrict the number of objects in a slab to implement
2204          * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition.
2205          */
2206         if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE)
2207                 size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align);
2208 
2209         left_over = calculate_slab_order(cachep, size, cachep->align, flags);
2210 
2211         if (!cachep->num)
2212                 return -E2BIG;
2213 
2214         freelist_size = calculate_freelist_size(cachep->num, cachep->align);
2215 
2216         /*
2217          * If the slab has been placed off-slab, and we have enough space then
2218          * move it on-slab. This is at the expense of any extra colouring.
2219          */
2220         if (flags & CFLGS_OFF_SLAB && left_over >= freelist_size) {
2221                 flags &= ~CFLGS_OFF_SLAB;
2222                 left_over -= freelist_size;
2223         }
2224 
2225         if (flags & CFLGS_OFF_SLAB) {
2226                 /* really off slab. No need for manual alignment */
2227                 freelist_size = calculate_freelist_size(cachep->num, 0);
2228 
2229 #ifdef CONFIG_PAGE_POISONING
2230                 /* If we're going to use the generic kernel_map_pages()
2231                  * poisoning, then it's going to smash the contents of
2232                  * the redzone and userword anyhow, so switch them off.
2233                  */
2234                 if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
2235                         flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2236 #endif
2237         }
2238 
2239         cachep->colour_off = cache_line_size();
2240         /* Offset must be a multiple of the alignment. */
2241         if (cachep->colour_off < cachep->align)
2242                 cachep->colour_off = cachep->align;
2243         cachep->colour = left_over / cachep->colour_off;
2244         cachep->freelist_size = freelist_size;
2245         cachep->flags = flags;
2246         cachep->allocflags = __GFP_COMP;
2247         if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
2248                 cachep->allocflags |= GFP_DMA;
2249         cachep->size = size;
2250         cachep->reciprocal_buffer_size = reciprocal_value(size);
2251 
2252         if (flags & CFLGS_OFF_SLAB) {
2253                 cachep->freelist_cache = kmalloc_slab(freelist_size, 0u);
2254                 /*
2255                  * This is a possibility for one of the kmalloc_{dma,}_caches.
2256                  * But since we go off slab only for object size greater than
2257                  * PAGE_SIZE/8, and kmalloc_{dma,}_caches get created
2258                  * in ascending order,this should not happen at all.
2259                  * But leave a BUG_ON for some lucky dude.
2260                  */
2261                 BUG_ON(ZERO_OR_NULL_PTR(cachep->freelist_cache));
2262         }
2263 
2264         err = setup_cpu_cache(cachep, gfp);
2265         if (err) {
2266                 __kmem_cache_shutdown(cachep);
2267                 return err;
2268         }
2269 
2270         return 0;
2271 }
2272 
2273 #if DEBUG
2274 static void check_irq_off(void)
2275 {
2276         BUG_ON(!irqs_disabled());
2277 }
2278 
2279 static void check_irq_on(void)
2280 {
2281         BUG_ON(irqs_disabled());
2282 }
2283 
2284 static void check_spinlock_acquired(struct kmem_cache *cachep)
2285 {
2286 #ifdef CONFIG_SMP
2287         check_irq_off();
2288         assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock);
2289 #endif
2290 }
2291 
2292 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2293 {
2294 #ifdef CONFIG_SMP
2295         check_irq_off();
2296         assert_spin_locked(&get_node(cachep, node)->list_lock);
2297 #endif
2298 }
2299 
2300 #else
2301 #define check_irq_off() do { } while(0)
2302 #define check_irq_on()  do { } while(0)
2303 #define check_spinlock_acquired(x) do { } while(0)
2304 #define check_spinlock_acquired_node(x, y) do { } while(0)
2305 #endif
2306 
2307 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
2308                         struct array_cache *ac,
2309                         int force, int node);
2310 
2311 static void do_drain(void *arg)
2312 {
2313         struct kmem_cache *cachep = arg;
2314         struct array_cache *ac;
2315         int node = numa_mem_id();
2316         struct kmem_cache_node *n;
2317         LIST_HEAD(list);
2318 
2319         check_irq_off();
2320         ac = cpu_cache_get(cachep);
2321         n = get_node(cachep, node);
2322         spin_lock(&n->list_lock);
2323         free_block(cachep, ac->entry, ac->avail, node, &list);
2324         spin_unlock(&n->list_lock);
2325         slabs_destroy(cachep, &list);
2326         ac->avail = 0;
2327 }
2328 
2329 static void drain_cpu_caches(struct kmem_cache *cachep)
2330 {
2331         struct kmem_cache_node *n;
2332         int node;
2333 
2334         on_each_cpu(do_drain, cachep, 1);
2335         check_irq_on();
2336         for_each_kmem_cache_node(cachep, node, n)
2337                 if (n->alien)
2338                         drain_alien_cache(cachep, n->alien);
2339 
2340         for_each_kmem_cache_node(cachep, node, n)
2341                 drain_array(cachep, n, n->shared, 1, node);
2342 }
2343 
2344 /*
2345  * Remove slabs from the list of free slabs.
2346  * Specify the number of slabs to drain in tofree.
2347  *
2348  * Returns the actual number of slabs released.
2349  */
2350 static int drain_freelist(struct kmem_cache *cache,
2351                         struct kmem_cache_node *n, int tofree)
2352 {
2353         struct list_head *p;
2354         int nr_freed;
2355         struct page *page;
2356 
2357         nr_freed = 0;
2358         while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
2359 
2360                 spin_lock_irq(&n->list_lock);
2361                 p = n->slabs_free.prev;
2362                 if (p == &n->slabs_free) {
2363                         spin_unlock_irq(&n->list_lock);
2364                         goto out;
2365                 }
2366 
2367                 page = list_entry(p, struct page, lru);
2368 #if DEBUG
2369                 BUG_ON(page->active);
2370 #endif
2371                 list_del(&page->lru);
2372                 /*
2373                  * Safe to drop the lock. The slab is no longer linked
2374                  * to the cache.
2375                  */
2376                 n->free_objects -= cache->num;
2377                 spin_unlock_irq(&n->list_lock);
2378                 slab_destroy(cache, page);
2379                 nr_freed++;
2380         }
2381 out:
2382         return nr_freed;
2383 }
2384 
2385 int __kmem_cache_shrink(struct kmem_cache *cachep, bool deactivate)
2386 {
2387         int ret = 0;
2388         int node;
2389         struct kmem_cache_node *n;
2390 
2391         drain_cpu_caches(cachep);
2392 
2393         check_irq_on();
2394         for_each_kmem_cache_node(cachep, node, n) {
2395                 drain_freelist(cachep, n, slabs_tofree(cachep, n));
2396 
2397                 ret += !list_empty(&n->slabs_full) ||
2398                         !list_empty(&n->slabs_partial);
2399         }
2400         return (ret ? 1 : 0);
2401 }
2402 
2403 int __kmem_cache_shutdown(struct kmem_cache *cachep)
2404 {
2405         int i;
2406         struct kmem_cache_node *n;
2407         int rc = __kmem_cache_shrink(cachep, false);
2408 
2409         if (rc)
2410                 return rc;
2411 
2412         free_percpu(cachep->cpu_cache);
2413 
2414         /* NUMA: free the node structures */
2415         for_each_kmem_cache_node(cachep, i, n) {
2416                 kfree(n->shared);
2417                 free_alien_cache(n->alien);
2418                 kfree(n);
2419                 cachep->node[i] = NULL;
2420         }
2421         return 0;
2422 }
2423 
2424 /*
2425  * Get the memory for a slab management obj.
2426  *
2427  * For a slab cache when the slab descriptor is off-slab, the
2428  * slab descriptor can't come from the same cache which is being created,
2429  * Because if it is the case, that means we defer the creation of
2430  * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point.
2431  * And we eventually call down to __kmem_cache_create(), which
2432  * in turn looks up in the kmalloc_{dma,}_caches for the disired-size one.
2433  * This is a "chicken-and-egg" problem.
2434  *
2435  * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches,
2436  * which are all initialized during kmem_cache_init().
2437  */
2438 static void *alloc_slabmgmt(struct kmem_cache *cachep,
2439                                    struct page *page, int colour_off,
2440                                    gfp_t local_flags, int nodeid)
2441 {
2442         void *freelist;
2443         void *addr = page_address(page);
2444 
2445         if (OFF_SLAB(cachep)) {
2446                 /* Slab management obj is off-slab. */
2447                 freelist = kmem_cache_alloc_node(cachep->freelist_cache,
2448                                               local_flags, nodeid);
2449                 if (!freelist)
2450                         return NULL;
2451         } else {
2452                 freelist = addr + colour_off;
2453                 colour_off += cachep->freelist_size;
2454         }
2455         page->active = 0;
2456         page->s_mem = addr + colour_off;
2457         return freelist;
2458 }
2459 
2460 static inline freelist_idx_t get_free_obj(struct page *page, unsigned int idx)
2461 {
2462         return ((freelist_idx_t *)page->freelist)[idx];
2463 }
2464 
2465 static inline void set_free_obj(struct page *page,
2466                                         unsigned int idx, freelist_idx_t val)
2467 {
2468         ((freelist_idx_t *)(page->freelist))[idx] = val;
2469 }
2470 
2471 static void cache_init_objs(struct kmem_cache *cachep,
2472                             struct page *page)
2473 {
2474         int i;
2475 
2476         for (i = 0; i < cachep->num; i++) {
2477                 void *objp = index_to_obj(cachep, page, i);
2478 #if DEBUG
2479                 /* need to poison the objs? */
2480                 if (cachep->flags & SLAB_POISON)
2481                         poison_obj(cachep, objp, POISON_FREE);
2482                 if (cachep->flags & SLAB_STORE_USER)
2483                         *dbg_userword(cachep, objp) = NULL;
2484 
2485                 if (cachep->flags & SLAB_RED_ZONE) {
2486                         *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2487                         *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2488                 }
2489                 /*
2490                  * Constructors are not allowed to allocate memory from the same
2491                  * cache which they are a constructor for.  Otherwise, deadlock.
2492                  * They must also be threaded.
2493                  */
2494                 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
2495                         cachep->ctor(objp + obj_offset(cachep));
2496 
2497                 if (cachep->flags & SLAB_RED_ZONE) {
2498                         if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2499                                 slab_error(cachep, "constructor overwrote the"
2500                                            " end of an object");
2501                         if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2502                                 slab_error(cachep, "constructor overwrote the"
2503                                            " start of an object");
2504                 }
2505                 if ((cachep->size % PAGE_SIZE) == 0 &&
2506                             OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
2507                         kernel_map_pages(virt_to_page(objp),
2508                                          cachep->size / PAGE_SIZE, 0);
2509 #else
2510                 if (cachep->ctor)
2511                         cachep->ctor(objp);
2512 #endif
2513                 set_obj_status(page, i, OBJECT_FREE);
2514                 set_free_obj(page, i, i);
2515         }
2516 }
2517 
2518 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
2519 {
2520         if (CONFIG_ZONE_DMA_FLAG) {
2521                 if (flags & GFP_DMA)
2522                         BUG_ON(!(cachep->allocflags & GFP_DMA));
2523                 else
2524                         BUG_ON(cachep->allocflags & GFP_DMA);
2525         }
2526 }
2527 
2528 static void *slab_get_obj(struct kmem_cache *cachep, struct page *page,
2529                                 int nodeid)
2530 {
2531         void *objp;
2532 
2533         objp = index_to_obj(cachep, page, get_free_obj(page, page->active));
2534         page->active++;
2535 #if DEBUG
2536         WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);
2537 #endif
2538 
2539         return objp;
2540 }
2541 
2542 static void slab_put_obj(struct kmem_cache *cachep, struct page *page,
2543                                 void *objp, int nodeid)
2544 {
2545         unsigned int objnr = obj_to_index(cachep, page, objp);
2546 #if DEBUG
2547         unsigned int i;
2548 
2549         /* Verify that the slab belongs to the intended node */
2550         WARN_ON(page_to_nid(virt_to_page(objp)) != nodeid);
2551 
2552         /* Verify double free bug */
2553         for (i = page->active; i < cachep->num; i++) {
2554                 if (get_free_obj(page, i) == objnr) {
2555                         printk(KERN_ERR "slab: double free detected in cache "
2556                                         "'%s', objp %p\n", cachep->name, objp);
2557                         BUG();
2558                 }
2559         }
2560 #endif
2561         page->active--;
2562         set_free_obj(page, page->active, objnr);
2563 }
2564 
2565 /*
2566  * Map pages beginning at addr to the given cache and slab. This is required
2567  * for the slab allocator to be able to lookup the cache and slab of a
2568  * virtual address for kfree, ksize, and slab debugging.
2569  */
2570 static void slab_map_pages(struct kmem_cache *cache, struct page *page,
2571                            void *freelist)
2572 {
2573         page->slab_cache = cache;
2574         page->freelist = freelist;
2575 }
2576 
2577 /*
2578  * Grow (by 1) the number of slabs within a cache.  This is called by
2579  * kmem_cache_alloc() when there are no active objs left in a cache.
2580  */
2581 static int cache_grow(struct kmem_cache *cachep,
2582                 gfp_t flags, int nodeid, struct page *page)
2583 {
2584         void *freelist;
2585         size_t offset;
2586         gfp_t local_flags;
2587         struct kmem_cache_node *n;
2588 
2589         /*
2590          * Be lazy and only check for valid flags here,  keeping it out of the
2591          * critical path in kmem_cache_alloc().
2592          */
2593         if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
2594                 pr_emerg("gfp: %u\n", flags & GFP_SLAB_BUG_MASK);
2595                 BUG();
2596         }
2597         local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2598 
2599         /* Take the node list lock to change the colour_next on this node */
2600         check_irq_off();
2601         n = get_node(cachep, nodeid);
2602         spin_lock(&n->list_lock);
2603 
2604         /* Get colour for the slab, and cal the next value. */
2605         offset = n->colour_next;
2606         n->colour_next++;
2607         if (n->colour_next >= cachep->colour)
2608                 n->colour_next = 0;
2609         spin_unlock(&n->list_lock);
2610 
2611         offset *= cachep->colour_off;
2612 
2613         if (local_flags & __GFP_WAIT)
2614                 local_irq_enable();
2615 
2616         /*
2617          * The test for missing atomic flag is performed here, rather than
2618          * the more obvious place, simply to reduce the critical path length
2619          * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
2620          * will eventually be caught here (where it matters).
2621          */
2622         kmem_flagcheck(cachep, flags);
2623 
2624         /*
2625          * Get mem for the objs.  Attempt to allocate a physical page from
2626          * 'nodeid'.
2627          */
2628         if (!page)
2629                 page = kmem_getpages(cachep, local_flags, nodeid);
2630         if (!page)
2631                 goto failed;
2632 
2633         /* Get slab management. */
2634         freelist = alloc_slabmgmt(cachep, page, offset,
2635                         local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
2636         if (!freelist)
2637                 goto opps1;
2638 
2639         slab_map_pages(cachep, page, freelist);
2640 
2641         cache_init_objs(cachep, page);
2642 
2643         if (local_flags & __GFP_WAIT)
2644                 local_irq_disable();
2645         check_irq_off();
2646         spin_lock(&n->list_lock);
2647 
2648         /* Make slab active. */
2649         list_add_tail(&page->lru, &(n->slabs_free));
2650         STATS_INC_GROWN(cachep);
2651         n->free_objects += cachep->num;
2652         spin_unlock(&n->list_lock);
2653         return 1;
2654 opps1:
2655         kmem_freepages(cachep, page);
2656 failed:
2657         if (local_flags & __GFP_WAIT)
2658                 local_irq_disable();
2659         return 0;
2660 }
2661 
2662 #if DEBUG
2663 
2664 /*
2665  * Perform extra freeing checks:
2666  * - detect bad pointers.
2667  * - POISON/RED_ZONE checking
2668  */
2669 static void kfree_debugcheck(const void *objp)
2670 {
2671         if (!virt_addr_valid(objp)) {
2672                 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
2673                        (unsigned long)objp);
2674                 BUG();
2675         }
2676 }
2677 
2678 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2679 {
2680         unsigned long long redzone1, redzone2;
2681 
2682         redzone1 = *dbg_redzone1(cache, obj);
2683         redzone2 = *dbg_redzone2(cache, obj);
2684 
2685         /*
2686          * Redzone is ok.
2687          */
2688         if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2689                 return;
2690 
2691         if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2692                 slab_error(cache, "double free detected");
2693         else
2694                 slab_error(cache, "memory outside object was overwritten");
2695 
2696         printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
2697                         obj, redzone1, redzone2);
2698 }
2699 
2700 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2701                                    unsigned long caller)
2702 {
2703         unsigned int objnr;
2704         struct page *page;
2705 
2706         BUG_ON(virt_to_cache(objp) != cachep);
2707 
2708         objp -= obj_offset(cachep);
2709         kfree_debugcheck(objp);
2710         page = virt_to_head_page(objp);
2711 
2712         if (cachep->flags & SLAB_RED_ZONE) {
2713                 verify_redzone_free(cachep, objp);
2714                 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2715                 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2716         }
2717         if (cachep->flags & SLAB_STORE_USER)
2718                 *dbg_userword(cachep, objp) = (void *)caller;
2719 
2720         objnr = obj_to_index(cachep, page, objp);
2721 
2722         BUG_ON(objnr >= cachep->num);
2723         BUG_ON(objp != index_to_obj(cachep, page, objnr));
2724 
2725         set_obj_status(page, objnr, OBJECT_FREE);
2726         if (cachep->flags & SLAB_POISON) {
2727 #ifdef CONFIG_DEBUG_PAGEALLOC
2728                 if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
2729                         store_stackinfo(cachep, objp, caller);
2730                         kernel_map_pages(virt_to_page(objp),
2731                                          cachep->size / PAGE_SIZE, 0);
2732                 } else {
2733                         poison_obj(cachep, objp, POISON_FREE);
2734                 }
2735 #else
2736                 poison_obj(cachep, objp, POISON_FREE);
2737 #endif
2738         }
2739         return objp;
2740 }
2741 
2742 #else
2743 #define kfree_debugcheck(x) do { } while(0)
2744 #define cache_free_debugcheck(x,objp,z) (objp)
2745 #endif
2746 
2747 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags,
2748                                                         bool force_refill)
2749 {
2750         int batchcount;
2751         struct kmem_cache_node *n;
2752         struct array_cache *ac;
2753         int node;
2754 
2755         check_irq_off();
2756         node = numa_mem_id();
2757         if (unlikely(force_refill))
2758                 goto force_grow;
2759 retry:
2760         ac = cpu_cache_get(cachep);
2761         batchcount = ac->batchcount;
2762         if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2763                 /*
2764                  * If there was little recent activity on this cache, then
2765                  * perform only a partial refill.  Otherwise we could generate
2766                  * refill bouncing.
2767                  */
2768                 batchcount = BATCHREFILL_LIMIT;
2769         }
2770         n = get_node(cachep, node);
2771 
2772         BUG_ON(ac->avail > 0 || !n);
2773         spin_lock(&n->list_lock);
2774 
2775         /* See if we can refill from the shared array */
2776         if (n->shared && transfer_objects(ac, n->shared, batchcount)) {
2777                 n->shared->touched = 1;
2778                 goto alloc_done;
2779         }
2780 
2781         while (batchcount > 0) {
2782                 struct list_head *entry;
2783                 struct page *page;
2784                 /* Get slab alloc is to come from. */
2785                 entry = n->slabs_partial.next;
2786                 if (entry == &n->slabs_partial) {
2787                         n->free_touched = 1;
2788                         entry = n->slabs_free.next;
2789                         if (entry == &n->slabs_free)
2790                                 goto must_grow;
2791                 }
2792 
2793                 page = list_entry(entry, struct page, lru);
2794                 check_spinlock_acquired(cachep);
2795 
2796                 /*
2797                  * The slab was either on partial or free list so
2798                  * there must be at least one object available for
2799                  * allocation.
2800                  */
2801                 BUG_ON(page->active >= cachep->num);
2802 
2803                 while (page->active < cachep->num && batchcount--) {
2804                         STATS_INC_ALLOCED(cachep);
2805                         STATS_INC_ACTIVE(cachep);
2806                         STATS_SET_HIGH(cachep);
2807 
2808                         ac_put_obj(cachep, ac, slab_get_obj(cachep, page,
2809                                                                         node));
2810                 }
2811 
2812                 /* move slabp to correct slabp list: */
2813                 list_del(&page->lru);
2814                 if (page->active == cachep->num)
2815                         list_add(&page->lru, &n->slabs_full);
2816                 else
2817                         list_add(&page->lru, &n->slabs_partial);
2818         }
2819 
2820 must_grow:
2821         n->free_objects -= ac->avail;
2822 alloc_done:
2823         spin_unlock(&n->list_lock);
2824 
2825         if (unlikely(!ac->avail)) {
2826                 int x;
2827 force_grow:
2828                 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
2829 
2830                 /* cache_grow can reenable interrupts, then ac could change. */
2831                 ac = cpu_cache_get(cachep);
2832                 node = numa_mem_id();
2833 
2834                 /* no objects in sight? abort */
2835                 if (!x && (ac->avail == 0 || force_refill))
2836                         return NULL;
2837 
2838                 if (!ac->avail)         /* objects refilled by interrupt? */
2839                         goto retry;
2840         }
2841         ac->touched = 1;
2842 
2843         return ac_get_obj(cachep, ac, flags, force_refill);
2844 }
2845 
2846 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
2847                                                 gfp_t flags)
2848 {
2849         might_sleep_if(flags & __GFP_WAIT);
2850 #if DEBUG
2851         kmem_flagcheck(cachep, flags);
2852 #endif
2853 }
2854 
2855 #if DEBUG
2856 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
2857                                 gfp_t flags, void *objp, unsigned long caller)
2858 {
2859         struct page *page;
2860 
2861         if (!objp)
2862                 return objp;
2863         if (cachep->flags & SLAB_POISON) {
2864 #ifdef CONFIG_DEBUG_PAGEALLOC
2865                 if ((cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
2866                         kernel_map_pages(virt_to_page(objp),
2867                                          cachep->size / PAGE_SIZE, 1);
2868                 else
2869                         check_poison_obj(cachep, objp);
2870 #else
2871                 check_poison_obj(cachep, objp);
2872 #endif
2873                 poison_obj(cachep, objp, POISON_INUSE);
2874         }
2875         if (cachep->flags & SLAB_STORE_USER)
2876                 *dbg_userword(cachep, objp) = (void *)caller;
2877 
2878         if (cachep->flags & SLAB_RED_ZONE) {
2879                 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
2880                                 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
2881                         slab_error(cachep, "double free, or memory outside"
2882                                                 " object was overwritten");
2883                         printk(KERN_ERR
2884                                 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
2885                                 objp, *dbg_redzone1(cachep, objp),
2886                                 *dbg_redzone2(cachep, objp));
2887                 }
2888                 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
2889                 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
2890         }
2891 
2892         page = virt_to_head_page(objp);
2893         set_obj_status(page, obj_to_index(cachep, page, objp), OBJECT_ACTIVE);
2894         objp += obj_offset(cachep);
2895         if (cachep->ctor && cachep->flags & SLAB_POISON)
2896                 cachep->ctor(objp);
2897         if (ARCH_SLAB_MINALIGN &&
2898             ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
2899                 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
2900                        objp, (int)ARCH_SLAB_MINALIGN);
2901         }
2902         return objp;
2903 }
2904 #else
2905 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
2906 #endif
2907 
2908 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
2909 {
2910         if (unlikely(cachep == kmem_cache))
2911                 return false;
2912 
2913         return should_failslab(cachep->object_size, flags, cachep->flags);
2914 }
2915 
2916 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
2917 {
2918         void *objp;
2919         struct array_cache *ac;
2920         bool force_refill = false;
2921 
2922         check_irq_off();
2923 
2924         ac = cpu_cache_get(cachep);
2925         if (likely(ac->avail)) {
2926                 ac->touched = 1;
2927                 objp = ac_get_obj(cachep, ac, flags, false);
2928 
2929                 /*
2930                  * Allow for the possibility all avail objects are not allowed
2931                  * by the current flags
2932                  */
2933                 if (objp) {
2934                         STATS_INC_ALLOCHIT(cachep);
2935                         goto out;
2936                 }
2937                 force_refill = true;
2938         }
2939 
2940         STATS_INC_ALLOCMISS(cachep);
2941         objp = cache_alloc_refill(cachep, flags, force_refill);
2942         /*
2943          * the 'ac' may be updated by cache_alloc_refill(),
2944          * and kmemleak_erase() requires its correct value.
2945          */
2946         ac = cpu_cache_get(cachep);
2947 
2948 out:
2949         /*
2950          * To avoid a false negative, if an object that is in one of the
2951          * per-CPU caches is leaked, we need to make sure kmemleak doesn't
2952          * treat the array pointers as a reference to the object.
2953          */
2954         if (objp)
2955                 kmemleak_erase(&ac->entry[ac->avail]);
2956         return objp;
2957 }
2958 
2959 #ifdef CONFIG_NUMA
2960 /*
2961  * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set.
2962  *
2963  * If we are in_interrupt, then process context, including cpusets and
2964  * mempolicy, may not apply and should not be used for allocation policy.
2965  */
2966 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
2967 {
2968         int nid_alloc, nid_here;
2969 
2970         if (in_interrupt() || (flags & __GFP_THISNODE))
2971                 return NULL;
2972         nid_alloc = nid_here = numa_mem_id();
2973         if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
2974                 nid_alloc = cpuset_slab_spread_node();
2975         else if (current->mempolicy)
2976                 nid_alloc = mempolicy_slab_node();
2977         if (nid_alloc != nid_here)
2978                 return ____cache_alloc_node(cachep, flags, nid_alloc);
2979         return NULL;
2980 }
2981 
2982 /*
2983  * Fallback function if there was no memory available and no objects on a
2984  * certain node and fall back is permitted. First we scan all the
2985  * available node for available objects. If that fails then we
2986  * perform an allocation without specifying a node. This allows the page
2987  * allocator to do its reclaim / fallback magic. We then insert the
2988  * slab into the proper nodelist and then allocate from it.
2989  */
2990 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
2991 {
2992         struct zonelist *zonelist;
2993         gfp_t local_flags;
2994         struct zoneref *z;
2995         struct zone *zone;
2996         enum zone_type high_zoneidx = gfp_zone(flags);
2997         void *obj = NULL;
2998         int nid;
2999         unsigned int cpuset_mems_cookie;
3000 
3001         if (flags & __GFP_THISNODE)
3002                 return NULL;
3003 
3004         local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
3005 
3006 retry_cpuset:
3007         cpuset_mems_cookie = read_mems_allowed_begin();
3008         zonelist = node_zonelist(mempolicy_slab_node(), flags);
3009 
3010 retry:
3011         /*
3012          * Look through allowed nodes for objects available
3013          * from existing per node queues.
3014          */
3015         for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3016                 nid = zone_to_nid(zone);
3017 
3018                 if (cpuset_zone_allowed(zone, flags) &&
3019                         get_node(cache, nid) &&
3020                         get_node(cache, nid)->free_objects) {
3021                                 obj = ____cache_alloc_node(cache,
3022                                         flags | GFP_THISNODE, nid);
3023                                 if (obj)
3024                                         break;
3025                 }
3026         }
3027 
3028         if (!obj) {
3029                 /*
3030                  * This allocation will be performed within the constraints
3031                  * of the current cpuset / memory policy requirements.
3032                  * We may trigger various forms of reclaim on the allowed
3033                  * set and go into memory reserves if necessary.
3034                  */
3035                 struct page *page;
3036 
3037                 if (local_flags & __GFP_WAIT)
3038                         local_irq_enable();
3039                 kmem_flagcheck(cache, flags);
3040                 page = kmem_getpages(cache, local_flags, numa_mem_id());
3041                 if (local_flags & __GFP_WAIT)
3042                         local_irq_disable();
3043                 if (page) {
3044                         /*
3045                          * Insert into the appropriate per node queues
3046                          */
3047                         nid = page_to_nid(page);
3048                         if (cache_grow(cache, flags, nid, page)) {
3049                                 obj = ____cache_alloc_node(cache,
3050                                         flags | GFP_THISNODE, nid);
3051                                 if (!obj)
3052                                         /*
3053                                          * Another processor may allocate the
3054                                          * objects in the slab since we are
3055                                          * not holding any locks.
3056                                          */
3057                                         goto retry;
3058                         } else {
3059                                 /* cache_grow already freed obj */
3060                                 obj = NULL;
3061                         }
3062                 }
3063         }
3064 
3065         if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie)))
3066                 goto retry_cpuset;
3067         return obj;
3068 }
3069 
3070 /*
3071  * A interface to enable slab creation on nodeid
3072  */
3073 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3074                                 int nodeid)
3075 {
3076         struct list_head *entry;
3077         struct page *page;
3078         struct kmem_cache_node *n;
3079         void *obj;
3080         int x;
3081 
3082         VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES);
3083         n = get_node(cachep, nodeid);
3084         BUG_ON(!n);
3085 
3086 retry:
3087         check_irq_off();
3088         spin_lock(&n->list_lock);
3089         entry = n->slabs_partial.next;
3090         if (entry == &n->slabs_partial) {
3091                 n->free_touched = 1;
3092                 entry = n->slabs_free.next;
3093                 if (entry == &n->slabs_free)
3094                         goto must_grow;
3095         }
3096 
3097         page = list_entry(entry, struct page, lru);
3098         check_spinlock_acquired_node(cachep, nodeid);
3099 
3100         STATS_INC_NODEALLOCS(cachep);
3101         STATS_INC_ACTIVE(cachep);
3102         STATS_SET_HIGH(cachep);
3103 
3104         BUG_ON(page->active == cachep->num);
3105 
3106         obj = slab_get_obj(cachep, page, nodeid);
3107         n->free_objects--;
3108         /* move slabp to correct slabp list: */
3109         list_del(&page->lru);
3110 
3111         if (page->active == cachep->num)
3112                 list_add(&page->lru, &n->slabs_full);
3113         else
3114                 list_add(&page->lru, &n->slabs_partial);
3115 
3116         spin_unlock(&n->list_lock);
3117         goto done;
3118 
3119 must_grow:
3120         spin_unlock(&n->list_lock);
3121         x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
3122         if (x)
3123                 goto retry;
3124 
3125         return fallback_alloc(cachep, flags);
3126 
3127 done:
3128         return obj;
3129 }
3130 
3131 static __always_inline void *
3132 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3133                    unsigned long caller)
3134 {
3135         unsigned long save_flags;
3136         void *ptr;
3137         int slab_node = numa_mem_id();
3138 
3139         flags &= gfp_allowed_mask;
3140 
3141         lockdep_trace_alloc(flags);
3142 
3143         if (slab_should_failslab(cachep, flags))
3144                 return NULL;
3145 
3146         cachep = memcg_kmem_get_cache(cachep, flags);
3147 
3148         cache_alloc_debugcheck_before(cachep, flags);
3149         local_irq_save(save_flags);
3150 
3151         if (nodeid == NUMA_NO_NODE)
3152                 nodeid = slab_node;
3153 
3154         if (unlikely(!get_node(cachep, nodeid))) {
3155                 /* Node not bootstrapped yet */
3156                 ptr = fallback_alloc(cachep, flags);
3157                 goto out;
3158         }
3159 
3160         if (nodeid == slab_node) {
3161                 /*
3162                  * Use the locally cached objects if possible.
3163                  * However ____cache_alloc does not allow fallback
3164                  * to other nodes. It may fail while we still have
3165                  * objects on other nodes available.
3166                  */
3167                 ptr = ____cache_alloc(cachep, flags);
3168                 if (ptr)
3169                         goto out;
3170         }
3171         /* ___cache_alloc_node can fall back to other nodes */
3172         ptr = ____cache_alloc_node(cachep, flags, nodeid);
3173   out:
3174         local_irq_restore(save_flags);
3175         ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3176         kmemleak_alloc_recursive(ptr, cachep->object_size, 1, cachep->flags,
3177                                  flags);
3178 
3179         if (likely(ptr)) {
3180                 kmemcheck_slab_alloc(cachep, flags, ptr, cachep->object_size);
3181                 if (unlikely(flags & __GFP_ZERO))
3182                         memset(ptr, 0, cachep->object_size);
3183         }
3184 
3185         memcg_kmem_put_cache(cachep);
3186         return ptr;
3187 }
3188 
3189 static __always_inline void *
3190 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3191 {
3192         void *objp;
3193 
3194         if (current->mempolicy || cpuset_do_slab_mem_spread()) {
3195                 objp = alternate_node_alloc(cache, flags);
3196                 if (objp)
3197                         goto out;
3198         }
3199         objp = ____cache_alloc(cache, flags);
3200 
3201         /*
3202          * We may just have run out of memory on the local node.
3203          * ____cache_alloc_node() knows how to locate memory on other nodes
3204          */
3205         if (!objp)
3206                 objp = ____cache_alloc_node(cache, flags, numa_mem_id());
3207 
3208   out:
3209         return objp;
3210 }
3211 #else
3212 
3213 static __always_inline void *
3214 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3215 {
3216         return ____cache_alloc(cachep, flags);
3217 }
3218 
3219 #endif /* CONFIG_NUMA */
3220 
3221 static __always_inline void *
3222 slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
3223 {
3224         unsigned long save_flags;
3225         void *objp;
3226 
3227         flags &= gfp_allowed_mask;
3228 
3229         lockdep_trace_alloc(flags);
3230 
3231         if (slab_should_failslab(cachep, flags))
3232                 return NULL;
3233 
3234         cachep = memcg_kmem_get_cache(cachep, flags);
3235 
3236         cache_alloc_debugcheck_before(cachep, flags);
3237         local_irq_save(save_flags);
3238         objp = __do_cache_alloc(cachep, flags);
3239         local_irq_restore(save_flags);
3240         objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3241         kmemleak_alloc_recursive(objp, cachep->object_size, 1, cachep->flags,
3242                                  flags);
3243         prefetchw(objp);
3244 
3245         if (likely(objp)) {
3246                 kmemcheck_slab_alloc(cachep, flags, objp, cachep->object_size);
3247                 if (unlikely(flags & __GFP_ZERO))
3248                         memset(objp, 0, cachep->object_size);
3249         }
3250 
3251         memcg_kmem_put_cache(cachep);
3252         return objp;
3253 }
3254 
3255 /*
3256  * Caller needs to acquire correct kmem_cache_node's list_lock
3257  * @list: List of detached free slabs should be freed by caller
3258  */
3259 static void free_block(struct kmem_cache *cachep, void **objpp,
3260                         int nr_objects, int node, struct list_head *list)
3261 {
3262         int i;
3263         struct kmem_cache_node *n = get_node(cachep, node);
3264 
3265         for (i = 0; i < nr_objects; i++) {
3266                 void *objp;
3267                 struct page *page;
3268 
3269                 clear_obj_pfmemalloc(&objpp[i]);
3270                 objp = objpp[i];
3271 
3272                 page = virt_to_head_page(objp);
3273                 list_del(&page->lru);
3274                 check_spinlock_acquired_node(cachep, node);
3275                 slab_put_obj(cachep, page, objp, node);
3276                 STATS_DEC_ACTIVE(cachep);
3277                 n->free_objects++;
3278 
3279                 /* fixup slab chains */
3280                 if (page->active == 0) {
3281                         if (n->free_objects > n->free_limit) {
3282                                 n->free_objects -= cachep->num;
3283                                 list_add_tail(&page->lru, list);
3284                         } else {
3285                                 list_add(&page->lru, &n->slabs_free);
3286                         }
3287                 } else {
3288                         /* Unconditionally move a slab to the end of the
3289                          * partial list on free - maximum time for the
3290                          * other objects to be freed, too.
3291                          */
3292                         list_add_tail(&page->lru, &n->slabs_partial);
3293                 }
3294         }
3295 }
3296 
3297 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3298 {
3299         int batchcount;
3300         struct kmem_cache_node *n;
3301         int node = numa_mem_id();
3302         LIST_HEAD(list);
3303 
3304         batchcount = ac->batchcount;
3305 #if DEBUG
3306         BUG_ON(!batchcount || batchcount > ac->avail);
3307 #endif
3308         check_irq_off();
3309         n = get_node(cachep, node);
3310         spin_lock(&n->list_lock);
3311         if (n->shared) {
3312                 struct array_cache *shared_array = n->shared;
3313                 int max = shared_array->limit - shared_array->avail;
3314                 if (max) {
3315                         if (batchcount > max)
3316                                 batchcount = max;
3317                         memcpy(&(shared_array->entry[shared_array->avail]),
3318                                ac->entry, sizeof(void *) * batchcount);
3319                         shared_array->avail += batchcount;
3320                         goto free_done;
3321                 }
3322         }
3323 
3324         free_block(cachep, ac->entry, batchcount, node, &list);
3325 free_done:
3326 #if STATS
3327         {
3328                 int i = 0;
3329                 struct list_head *p;
3330 
3331                 p = n->slabs_free.next;
3332                 while (p != &(n->slabs_free)) {
3333                         struct page *page;
3334 
3335                         page = list_entry(p, struct page, lru);
3336                         BUG_ON(page->active);
3337 
3338                         i++;
3339                         p = p->next;
3340                 }
3341                 STATS_SET_FREEABLE(cachep, i);
3342         }
3343 #endif
3344         spin_unlock(&n->list_lock);
3345         slabs_destroy(cachep, &list);
3346         ac->avail -= batchcount;
3347         memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3348 }
3349 
3350 /*
3351  * Release an obj back to its cache. If the obj has a constructed state, it must
3352  * be in this state _before_ it is released.  Called with disabled ints.
3353  */
3354 static inline void __cache_free(struct kmem_cache *cachep, void *objp,
3355                                 unsigned long caller)
3356 {
3357         struct array_cache *ac = cpu_cache_get(cachep);
3358 
3359         check_irq_off();
3360         kmemleak_free_recursive(objp, cachep->flags);
3361         objp = cache_free_debugcheck(cachep, objp, caller);
3362 
3363         kmemcheck_slab_free(cachep, objp, cachep->object_size);
3364 
3365         /*
3366          * Skip calling cache_free_alien() when the platform is not numa.
3367          * This will avoid cache misses that happen while accessing slabp (which
3368          * is per page memory  reference) to get nodeid. Instead use a global
3369          * variable to skip the call, which is mostly likely to be present in
3370          * the cache.
3371          */
3372         if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3373                 return;
3374 
3375         if (ac->avail < ac->limit) {
3376                 STATS_INC_FREEHIT(cachep);
3377         } else {
3378                 STATS_INC_FREEMISS(cachep);
3379                 cache_flusharray(cachep, ac);
3380         }
3381 
3382         ac_put_obj(cachep, ac, objp);
3383 }
3384 
3385 /**
3386  * kmem_cache_alloc - Allocate an object
3387  * @cachep: The cache to allocate from.
3388  * @flags: See kmalloc().
3389  *
3390  * Allocate an object from this cache.  The flags are only relevant
3391  * if the cache has no available objects.
3392  */
3393 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3394 {
3395         void *ret = slab_alloc(cachep, flags, _RET_IP_);
3396 
3397         trace_kmem_cache_alloc(_RET_IP_, ret,
3398                                cachep->object_size, cachep->size, flags);
3399 
3400         return ret;
3401 }
3402 EXPORT_SYMBOL(kmem_cache_alloc);
3403 
3404 #ifdef CONFIG_TRACING
3405 void *
3406 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
3407 {
3408         void *ret;
3409 
3410         ret = slab_alloc(cachep, flags, _RET_IP_);
3411 
3412         trace_kmalloc(_RET_IP_, ret,
3413                       size, cachep->size, flags);
3414         return ret;
3415 }
3416 EXPORT_SYMBOL(kmem_cache_alloc_trace);
3417 #endif
3418 
3419 #ifdef CONFIG_NUMA
3420 /**
3421  * kmem_cache_alloc_node - Allocate an object on the specified node
3422  * @cachep: The cache to allocate from.
3423  * @flags: See kmalloc().
3424  * @nodeid: node number of the target node.
3425  *
3426  * Identical to kmem_cache_alloc but it will allocate memory on the given
3427  * node, which can improve the performance for cpu bound structures.
3428  *
3429  * Fallback to other node is possible if __GFP_THISNODE is not set.
3430  */
3431 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3432 {
3433         void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3434 
3435         trace_kmem_cache_alloc_node(_RET_IP_, ret,
3436                                     cachep->object_size, cachep->size,
3437                                     flags, nodeid);
3438 
3439         return ret;
3440 }
3441 EXPORT_SYMBOL(kmem_cache_alloc_node);
3442 
3443 #ifdef CONFIG_TRACING
3444 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
3445                                   gfp_t flags,
3446                                   int nodeid,
3447                                   size_t size)
3448 {
3449         void *ret;
3450 
3451         ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3452 
3453         trace_kmalloc_node(_RET_IP_, ret,
3454                            size, cachep->size,
3455                            flags, nodeid);
3456         return ret;
3457 }
3458 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3459 #endif
3460 
3461 static __always_inline void *
3462 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
3463 {
3464         struct kmem_cache *cachep;
3465 
3466         cachep = kmalloc_slab(size, flags);
3467         if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3468                 return cachep;
3469         return kmem_cache_alloc_node_trace(cachep, flags, node, size);
3470 }
3471 
3472 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3473 {
3474         return __do_kmalloc_node(size, flags, node, _RET_IP_);
3475 }
3476 EXPORT_SYMBOL(__kmalloc_node);
3477 
3478 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3479                 int node, unsigned long caller)
3480 {
3481         return __do_kmalloc_node(size, flags, node, caller);
3482 }
3483 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3484 #endif /* CONFIG_NUMA */
3485 
3486 /**
3487  * __do_kmalloc - allocate memory
3488  * @size: how many bytes of memory are required.
3489  * @flags: the type of memory to allocate (see kmalloc).
3490  * @caller: function caller for debug tracking of the caller
3491  */
3492 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3493                                           unsigned long caller)
3494 {
3495         struct kmem_cache *cachep;
3496         void *ret;
3497 
3498         cachep = kmalloc_slab(size, flags);
3499         if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3500                 return cachep;
3501         ret = slab_alloc(cachep, flags, caller);
3502 
3503         trace_kmalloc(caller, ret,
3504                       size, cachep->size, flags);
3505 
3506         return ret;
3507 }
3508 
3509 void *__kmalloc(size_t size, gfp_t flags)
3510 {
3511         return __do_kmalloc(size, flags, _RET_IP_);
3512 }
3513 EXPORT_SYMBOL(__kmalloc);
3514 
3515 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3516 {
3517         return __do_kmalloc(size, flags, caller);
3518 }
3519 EXPORT_SYMBOL(__kmalloc_track_caller);
3520 
3521 /**
3522  * kmem_cache_free - Deallocate an object
3523  * @cachep: The cache the allocation was from.
3524  * @objp: The previously allocated object.
3525  *
3526  * Free an object which was previously allocated from this
3527  * cache.
3528  */
3529 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3530 {
3531         unsigned long flags;
3532         cachep = cache_from_obj(cachep, objp);
3533         if (!cachep)
3534                 return;
3535 
3536         local_irq_save(flags);
3537         debug_check_no_locks_freed(objp, cachep->object_size);
3538         if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3539                 debug_check_no_obj_freed(objp, cachep->object_size);
3540         __cache_free(cachep, objp, _RET_IP_);
3541         local_irq_restore(flags);
3542 
3543         trace_kmem_cache_free(_RET_IP_, objp);
3544 }
3545 EXPORT_SYMBOL(kmem_cache_free);
3546 
3547 /**
3548  * kfree - free previously allocated memory
3549  * @objp: pointer returned by kmalloc.
3550  *
3551  * If @objp is NULL, no operation is performed.
3552  *
3553  * Don't free memory not originally allocated by kmalloc()
3554  * or you will run into trouble.
3555  */
3556 void kfree(const void *objp)
3557 {
3558         struct kmem_cache *c;
3559         unsigned long flags;
3560 
3561         trace_kfree(_RET_IP_, objp);
3562 
3563         if (unlikely(ZERO_OR_NULL_PTR(objp)))
3564                 return;
3565         local_irq_save(flags);
3566         kfree_debugcheck(objp);
3567         c = virt_to_cache(objp);
3568         debug_check_no_locks_freed(objp, c->object_size);
3569 
3570         debug_check_no_obj_freed(objp, c->object_size);
3571         __cache_free(c, (void *)objp, _RET_IP_);
3572         local_irq_restore(flags);
3573 }
3574 EXPORT_SYMBOL(kfree);
3575 
3576 /*
3577  * This initializes kmem_cache_node or resizes various caches for all nodes.
3578  */
3579 static int alloc_kmem_cache_node(struct kmem_cache *cachep, gfp_t gfp)
3580 {
3581         int node;
3582         struct kmem_cache_node *n;
3583         struct array_cache *new_shared;
3584         struct alien_cache **new_alien = NULL;
3585 
3586         for_each_online_node(node) {
3587 
3588                 if (use_alien_caches) {
3589                         new_alien = alloc_alien_cache(node, cachep->limit, gfp);
3590                         if (!new_alien)
3591                                 goto fail;
3592                 }
3593 
3594                 new_shared = NULL;
3595                 if (cachep->shared) {
3596                         new_shared = alloc_arraycache(node,
3597                                 cachep->shared*cachep->batchcount,
3598                                         0xbaadf00d, gfp);
3599                         if (!new_shared) {
3600                                 free_alien_cache(new_alien);
3601                                 goto fail;
3602                         }
3603                 }
3604 
3605                 n = get_node(cachep, node);
3606                 if (n) {
3607                         struct array_cache *shared = n->shared;
3608                         LIST_HEAD(list);
3609 
3610                         spin_lock_irq(&n->list_lock);
3611 
3612                         if (shared)
3613                                 free_block(cachep, shared->entry,
3614                                                 shared->avail, node, &list);
3615 
3616                         n->shared = new_shared;
3617                         if (!n->alien) {
3618                                 n->alien = new_alien;
3619                                 new_alien = NULL;
3620                         }
3621                         n->free_limit = (1 + nr_cpus_node(node)) *
3622                                         cachep->batchcount + cachep->num;
3623                         spin_unlock_irq(&n->list_lock);
3624                         slabs_destroy(cachep, &list);
3625                         kfree(shared);
3626                         free_alien_cache(new_alien);
3627                         continue;
3628                 }
3629                 n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
3630                 if (!n) {
3631                         free_alien_cache(new_alien);
3632                         kfree(new_shared);
3633                         goto fail;
3634                 }
3635 
3636                 kmem_cache_node_init(n);
3637                 n->next_reap = jiffies + REAPTIMEOUT_NODE +
3638                                 ((unsigned long)cachep) % REAPTIMEOUT_NODE;
3639                 n->shared = new_shared;
3640                 n->alien = new_alien;
3641                 n->free_limit = (1 + nr_cpus_node(node)) *
3642                                         cachep->batchcount + cachep->num;
3643                 cachep->node[node] = n;
3644         }
3645         return 0;
3646 
3647 fail:
3648         if (!cachep->list.next) {
3649                 /* Cache is not active yet. Roll back what we did */
3650                 node--;
3651                 while (node >= 0) {
3652                         n = get_node(cachep, node);
3653                         if (n) {
3654                                 kfree(n->shared);
3655                                 free_alien_cache(n->alien);
3656                                 kfree(n);
3657                                 cachep->node[node] = NULL;
3658                         }
3659                         node--;
3660                 }
3661         }
3662         return -ENOMEM;
3663 }
3664 
3665 /* Always called with the slab_mutex held */
3666 static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
3667                                 int batchcount, int shared, gfp_t gfp)
3668 {
3669         struct array_cache __percpu *cpu_cache, *prev;
3670         int cpu;
3671 
3672         cpu_cache = alloc_kmem_cache_cpus(cachep, limit, batchcount);
3673         if (!cpu_cache)
3674                 return -ENOMEM;
3675 
3676         prev = cachep->cpu_cache;
3677         cachep->cpu_cache = cpu_cache;
3678         kick_all_cpus_sync();
3679 
3680         check_irq_on();
3681         cachep->batchcount = batchcount;
3682         cachep->limit = limit;
3683         cachep->shared = shared;
3684 
3685         if (!prev)
3686                 goto alloc_node;
3687 
3688         for_each_online_cpu(cpu) {
3689                 LIST_HEAD(list);
3690                 int node;
3691                 struct kmem_cache_node *n;
3692                 struct array_cache *ac = per_cpu_ptr(prev, cpu);
3693 
3694                 node = cpu_to_mem(cpu);
3695                 n = get_node(cachep, node);
3696                 spin_lock_irq(&n->list_lock);
3697                 free_block(cachep, ac->entry, ac->avail, node, &list);
3698                 spin_unlock_irq(&n->list_lock);
3699                 slabs_destroy(cachep, &list);
3700         }
3701         free_percpu(prev);
3702 
3703 alloc_node:
3704         return alloc_kmem_cache_node(cachep, gfp);
3705 }
3706 
3707 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3708                                 int batchcount, int shared, gfp_t gfp)
3709 {
3710         int ret;
3711         struct kmem_cache *c;
3712 
3713         ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3714 
3715         if (slab_state < FULL)
3716                 return ret;
3717 
3718         if ((ret < 0) || !is_root_cache(cachep))
3719                 return ret;
3720 
3721         lockdep_assert_held(&slab_mutex);
3722         for_each_memcg_cache(c, cachep) {
3723                 /* return value determined by the root cache only */
3724                 __do_tune_cpucache(c, limit, batchcount, shared, gfp);
3725         }
3726 
3727         return ret;
3728 }
3729 
3730 /* Called with slab_mutex held always */
3731 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3732 {
3733         int err;
3734         int limit = 0;
3735         int shared = 0;
3736         int batchcount = 0;
3737 
3738         if (!is_root_cache(cachep)) {
3739                 struct kmem_cache *root = memcg_root_cache(cachep);
3740                 limit = root->limit;
3741                 shared = root->shared;
3742                 batchcount = root->batchcount;
3743         }
3744 
3745         if (limit && shared && batchcount)
3746                 goto skip_setup;
3747         /*
3748          * The head array serves three purposes:
3749          * - create a LIFO ordering, i.e. return objects that are cache-warm
3750          * - reduce the number of spinlock operations.
3751          * - reduce the number of linked list operations on the slab and
3752          *   bufctl chains: array operations are cheaper.
3753          * The numbers are guessed, we should auto-tune as described by
3754          * Bonwick.
3755          */
3756         if (cachep->size > 131072)
3757                 limit = 1;
3758         else if (cachep->size > PAGE_SIZE)
3759                 limit = 8;
3760         else if (cachep->size > 1024)
3761                 limit = 24;
3762         else if (cachep->size > 256)
3763                 limit = 54;
3764         else
3765                 limit = 120;
3766 
3767         /*
3768          * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3769          * allocation behaviour: Most allocs on one cpu, most free operations
3770          * on another cpu. For these cases, an efficient object passing between
3771          * cpus is necessary. This is provided by a shared array. The array
3772          * replaces Bonwick's magazine layer.
3773          * On uniprocessor, it's functionally equivalent (but less efficient)
3774          * to a larger limit. Thus disabled by default.
3775          */
3776         shared = 0;
3777         if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
3778                 shared = 8;
3779 
3780 #if DEBUG
3781         /*
3782          * With debugging enabled, large batchcount lead to excessively long
3783          * periods with disabled local interrupts. Limit the batchcount
3784          */
3785         if (limit > 32)
3786                 limit = 32;
3787 #endif
3788         batchcount = (limit + 1) / 2;
3789 skip_setup:
3790         err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3791         if (err)
3792                 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
3793                        cachep->name, -err);
3794         return err;
3795 }
3796 
3797 /*
3798  * Drain an array if it contains any elements taking the node lock only if
3799  * necessary. Note that the node listlock also protects the array_cache
3800  * if drain_array() is used on the shared array.
3801  */
3802 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
3803                          struct array_cache *ac, int force, int node)
3804 {
3805         LIST_HEAD(list);
3806         int tofree;
3807 
3808         if (!ac || !ac->avail)
3809                 return;
3810         if (ac->touched && !force) {
3811                 ac->touched = 0;
3812         } else {
3813                 spin_lock_irq(&n->list_lock);
3814                 if (ac->avail) {
3815                         tofree = force ? ac->avail : (ac->limit + 4) / 5;
3816                         if (tofree > ac->avail)
3817                                 tofree = (ac->avail + 1) / 2;
3818                         free_block(cachep, ac->entry, tofree, node, &list);
3819                         ac->avail -= tofree;
3820                         memmove(ac->entry, &(ac->entry[tofree]),
3821                                 sizeof(void *) * ac->avail);
3822                 }
3823                 spin_unlock_irq(&n->list_lock);
3824                 slabs_destroy(cachep, &list);
3825         }
3826 }
3827 
3828 /**
3829  * cache_reap - Reclaim memory from caches.
3830  * @w: work descriptor
3831  *
3832  * Called from workqueue/eventd every few seconds.
3833  * Purpose:
3834  * - clear the per-cpu caches for this CPU.
3835  * - return freeable pages to the main free memory pool.
3836  *
3837  * If we cannot acquire the cache chain mutex then just give up - we'll try
3838  * again on the next iteration.
3839  */
3840 static void cache_reap(struct work_struct *w)
3841 {
3842         struct kmem_cache *searchp;
3843         struct kmem_cache_node *n;
3844         int node = numa_mem_id();
3845         struct delayed_work *work = to_delayed_work(w);
3846 
3847         if (!mutex_trylock(&slab_mutex))
3848                 /* Give up. Setup the next iteration. */
3849                 goto out;
3850 
3851         list_for_each_entry(searchp, &slab_caches, list) {
3852                 check_irq_on();
3853 
3854                 /*
3855                  * We only take the node lock if absolutely necessary and we
3856                  * have established with reasonable certainty that
3857                  * we can do some work if the lock was obtained.
3858                  */
3859                 n = get_node(searchp, node);
3860 
3861                 reap_alien(searchp, n);
3862 
3863                 drain_array(searchp, n, cpu_cache_get(searchp), 0, node);
3864 
3865                 /*
3866                  * These are racy checks but it does not matter
3867                  * if we skip one check or scan twice.
3868                  */
3869                 if (time_after(n->next_reap, jiffies))
3870                         goto next;
3871 
3872                 n->next_reap = jiffies + REAPTIMEOUT_NODE;
3873 
3874                 drain_array(searchp, n, n->shared, 0, node);
3875 
3876                 if (n->free_touched)
3877                         n->free_touched = 0;
3878                 else {
3879                         int freed;
3880 
3881                         freed = drain_freelist(searchp, n, (n->free_limit +
3882                                 5 * searchp->num - 1) / (5 * searchp->num));
3883                         STATS_ADD_REAPED(searchp, freed);
3884                 }
3885 next:
3886                 cond_resched();
3887         }
3888         check_irq_on();
3889         mutex_unlock(&slab_mutex);
3890         next_reap_node();
3891 out:
3892         /* Set up the next iteration */
3893         schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC));
3894 }
3895 
3896 #ifdef CONFIG_SLABINFO
3897 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
3898 {
3899         struct page *page;
3900         unsigned long active_objs;
3901         unsigned long num_objs;
3902         unsigned long active_slabs = 0;
3903         unsigned long num_slabs, free_objects = 0, shared_avail = 0;
3904         const char *name;
3905         char *error = NULL;
3906         int node;
3907         struct kmem_cache_node *n;
3908 
3909         active_objs = 0;
3910         num_slabs = 0;
3911         for_each_kmem_cache_node(cachep, node, n) {
3912 
3913                 check_irq_on();
3914                 spin_lock_irq(&n->list_lock);
3915 
3916                 list_for_each_entry(page, &n->slabs_full, lru) {
3917                         if (page->active != cachep->num && !error)
3918                                 error = "slabs_full accounting error";
3919                         active_objs += cachep->num;
3920                         active_slabs++;
3921                 }
3922                 list_for_each_entry(page, &n->slabs_partial, lru) {
3923                         if (page->active == cachep->num && !error)
3924                                 error = "slabs_partial accounting error";
3925                         if (!page->active && !error)
3926                                 error = "slabs_partial accounting error";
3927                         active_objs += page->active;
3928                         active_slabs++;
3929                 }
3930                 list_for_each_entry(page, &n->slabs_free, lru) {
3931                         if (page->active && !error)
3932                                 error = "slabs_free accounting error";
3933                         num_slabs++;
3934                 }
3935                 free_objects += n->free_objects;
3936                 if (n->shared)
3937                         shared_avail += n->shared->avail;
3938 
3939                 spin_unlock_irq(&n->list_lock);
3940         }
3941         num_slabs += active_slabs;
3942         num_objs = num_slabs * cachep->num;
3943         if (num_objs - active_objs != free_objects && !error)
3944                 error = "free_objects accounting error";
3945 
3946         name = cachep->name;
3947         if (error)
3948                 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
3949 
3950         sinfo->active_objs = active_objs;
3951         sinfo->num_objs = num_objs;
3952         sinfo->active_slabs = active_slabs;
3953         sinfo->num_slabs = num_slabs;
3954         sinfo->shared_avail = shared_avail;
3955         sinfo->limit = cachep->limit;
3956         sinfo->batchcount = cachep->batchcount;
3957         sinfo->shared = cachep->shared;
3958         sinfo->objects_per_slab = cachep->num;
3959         sinfo->cache_order = cachep->gfporder;
3960 }
3961 
3962 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
3963 {
3964 #if STATS
3965         {                       /* node stats */
3966                 unsigned long high = cachep->high_mark;
3967                 unsigned long allocs = cachep->num_allocations;
3968                 unsigned long grown = cachep->grown;
3969                 unsigned long reaped = cachep->reaped;
3970                 unsigned long errors = cachep->errors;
3971                 unsigned long max_freeable = cachep->max_freeable;
3972                 unsigned long node_allocs = cachep->node_allocs;
3973                 unsigned long node_frees = cachep->node_frees;
3974                 unsigned long overflows = cachep->node_overflow;
3975 
3976                 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu "
3977                            "%4lu %4lu %4lu %4lu %4lu",
3978                            allocs, high, grown,
3979                            reaped, errors, max_freeable, node_allocs,
3980                            node_frees, overflows);
3981         }
3982         /* cpu stats */
3983         {
3984                 unsigned long allochit = atomic_read(&cachep->allochit);
3985                 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
3986                 unsigned long freehit = atomic_read(&cachep->freehit);
3987                 unsigned long freemiss = atomic_read(&cachep->freemiss);
3988 
3989                 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
3990                            allochit, allocmiss, freehit, freemiss);
3991         }
3992 #endif
3993 }
3994 
3995 #define MAX_SLABINFO_WRITE 128
3996 /**
3997  * slabinfo_write - Tuning for the slab allocator
3998  * @file: unused
3999  * @buffer: user buffer
4000  * @count: data length
4001  * @ppos: unused
4002  */
4003 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
4004                        size_t count, loff_t *ppos)
4005 {
4006         char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4007         int limit, batchcount, shared, res;
4008         struct kmem_cache *cachep;
4009 
4010         if (count > MAX_SLABINFO_WRITE)
4011                 return -EINVAL;
4012         if (copy_from_user(&kbuf, buffer, count))
4013                 return -EFAULT;
4014         kbuf[MAX_SLABINFO_WRITE] = '\0';
4015 
4016         tmp = strchr(kbuf, ' ');
4017         if (!tmp)
4018                 return -EINVAL;
4019         *tmp = '\0';
4020         tmp++;
4021         if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4022                 return -EINVAL;
4023 
4024         /* Find the cache in the chain of caches. */
4025         mutex_lock(&slab_mutex);
4026         res = -EINVAL;
4027         list_for_each_entry(cachep, &slab_caches, list) {
4028                 if (!strcmp(cachep->name, kbuf)) {
4029                         if (limit < 1 || batchcount < 1 ||
4030                                         batchcount > limit || shared < 0) {
4031                                 res = 0;
4032                         } else {
4033                                 res = do_tune_cpucache(cachep, limit,
4034                                                        batchcount, shared,
4035                                                        GFP_KERNEL);
4036                         }
4037                         break;
4038                 }
4039         }
4040         mutex_unlock(&slab_mutex);
4041         if (res >= 0)
4042                 res = count;
4043         return res;
4044 }
4045 
4046 #ifdef CONFIG_DEBUG_SLAB_LEAK
4047 
4048 static inline int add_caller(unsigned long *n, unsigned long v)
4049 {
4050         unsigned long *p;
4051         int l;
4052         if (!v)
4053                 return 1;
4054         l = n[1];
4055         p = n + 2;
4056         while (l) {
4057                 int i = l/2;
4058                 unsigned long *q = p + 2 * i;
4059                 if (*q == v) {
4060                         q[1]++;
4061                         return 1;
4062                 }
4063                 if (*q > v) {
4064                         l = i;
4065                 } else {
4066                         p = q + 2;
4067                         l -= i + 1;
4068                 }
4069         }
4070         if (++n[1] == n[0])
4071                 return 0;
4072         memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4073         p[0] = v;
4074         p[1] = 1;
4075         return 1;
4076 }
4077 
4078 static void handle_slab(unsigned long *n, struct kmem_cache *c,
4079                                                 struct page *page)
4080 {
4081         void *p;
4082         int i;
4083 
4084         if (n[0] == n[1])
4085                 return;
4086         for (i = 0, p = page->s_mem; i < c->num; i++, p += c->size) {
4087                 if (get_obj_status(page, i) != OBJECT_ACTIVE)
4088                         continue;
4089 
4090                 if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
4091                         return;
4092         }
4093 }
4094 
4095 static void show_symbol(struct seq_file *m, unsigned long address)
4096 {
4097 #ifdef CONFIG_KALLSYMS
4098         unsigned long offset, size;
4099         char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4100 
4101         if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4102                 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4103                 if (modname[0])
4104                         seq_printf(m, " [%s]", modname);
4105                 return;
4106         }
4107 #endif
4108         seq_printf(m, "%p", (void *)address);
4109 }
4110 
4111 static int leaks_show(struct seq_file *m, void *p)
4112 {
4113         struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
4114         struct page *page;
4115         struct kmem_cache_node *n;
4116         const char *name;
4117         unsigned long *x = m->private;
4118         int node;
4119         int i;
4120 
4121         if (!(cachep->flags & SLAB_STORE_USER))
4122                 return 0;
4123         if (!(cachep->flags & SLAB_RED_ZONE))
4124                 return 0;
4125 
4126         /* OK, we can do it */
4127 
4128         x[1] = 0;
4129 
4130         for_each_kmem_cache_node(cachep, node, n) {
4131 
4132                 check_irq_on();
4133                 spin_lock_irq(&n->list_lock);
4134 
4135                 list_for_each_entry(page, &n->slabs_full, lru)
4136                         handle_slab(x, cachep, page);
4137                 list_for_each_entry(page, &n->slabs_partial, lru)
4138                         handle_slab(x, cachep, page);
4139                 spin_unlock_irq(&n->list_lock);
4140         }
4141         name = cachep->name;
4142         if (x[0] == x[1]) {
4143                 /* Increase the buffer size */
4144                 mutex_unlock(&slab_mutex);
4145                 m->private = kzalloc(x[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4146                 if (!m->private) {
4147                         /* Too bad, we are really out */
4148                         m->private = x;
4149                         mutex_lock(&slab_mutex);
4150                         return -ENOMEM;
4151                 }
4152                 *(unsigned long *)m->private = x[0] * 2;
4153                 kfree(x);
4154                 mutex_lock(&slab_mutex);
4155                 /* Now make sure this entry will be retried */
4156                 m->count = m->size;
4157                 return 0;
4158         }
4159         for (i = 0; i < x[1]; i++) {
4160                 seq_printf(m, "%s: %lu ", name, x[2*i+3]);
4161                 show_symbol(m, x[2*i+2]);
4162                 seq_putc(m, '\n');
4163         }
4164 
4165         return 0;
4166 }
4167 
4168 static const struct seq_operations slabstats_op = {
4169         .start = slab_start,
4170         .next = slab_next,
4171         .stop = slab_stop,
4172         .show = leaks_show,
4173 };
4174 
4175 static int slabstats_open(struct inode *inode, struct file *file)
4176 {
4177         unsigned long *n;
4178 
4179         n = __seq_open_private(file, &slabstats_op, PAGE_SIZE);
4180         if (!n)
4181                 return -ENOMEM;
4182 
4183         *n = PAGE_SIZE / (2 * sizeof(unsigned long));
4184 
4185         return 0;
4186 }
4187 
4188 static const struct file_operations proc_slabstats_operations = {
4189         .open           = slabstats_open,
4190         .read           = seq_read,
4191         .llseek         = seq_lseek,
4192         .release        = seq_release_private,
4193 };
4194 #endif
4195 
4196 static int __init slab_proc_init(void)
4197 {
4198 #ifdef CONFIG_DEBUG_SLAB_LEAK
4199         proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4200 #endif
4201         return 0;
4202 }
4203 module_init(slab_proc_init);
4204 #endif
4205 
4206 /**
4207  * ksize - get the actual amount of memory allocated for a given object
4208  * @objp: Pointer to the object
4209  *
4210  * kmalloc may internally round up allocations and return more memory
4211  * than requested. ksize() can be used to determine the actual amount of
4212  * memory allocated. The caller may use this additional memory, even though
4213  * a smaller amount of memory was initially specified with the kmalloc call.
4214  * The caller must guarantee that objp points to a valid object previously
4215  * allocated with either kmalloc() or kmem_cache_alloc(). The object
4216  * must not be freed during the duration of the call.
4217  */
4218 size_t ksize(const void *objp)
4219 {
4220         BUG_ON(!objp);
4221         if (unlikely(objp == ZERO_SIZE_PTR))
4222                 return 0;
4223 
4224         return virt_to_cache(objp)->object_size;
4225 }
4226 EXPORT_SYMBOL(ksize);
4227 

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