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Linux/mm/slab.c

  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  * struct array_cache
173  *
174  * Purpose:
175  * - LIFO ordering, to hand out cache-warm objects from _alloc
176  * - reduce the number of linked list operations
177  * - reduce spinlock operations
178  *
179  * The limit is stored in the per-cpu structure to reduce the data cache
180  * footprint.
181  *
182  */
183 struct array_cache {
184         unsigned int avail;
185         unsigned int limit;
186         unsigned int batchcount;
187         unsigned int touched;
188         void *entry[];  /*
189                          * Must have this definition in here for the proper
190                          * alignment of array_cache. Also simplifies accessing
191                          * the entries.
192                          */
193 };
194 
195 struct alien_cache {
196         spinlock_t lock;
197         struct array_cache ac;
198 };
199 
200 /*
201  * Need this for bootstrapping a per node allocator.
202  */
203 #define NUM_INIT_LISTS (2 * MAX_NUMNODES)
204 static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS];
205 #define CACHE_CACHE 0
206 #define SIZE_NODE (MAX_NUMNODES)
207 
208 static int drain_freelist(struct kmem_cache *cache,
209                         struct kmem_cache_node *n, int tofree);
210 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
211                         int node, struct list_head *list);
212 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list);
213 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
214 static void cache_reap(struct work_struct *unused);
215 
216 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
217                                                 void **list);
218 static inline void fixup_slab_list(struct kmem_cache *cachep,
219                                 struct kmem_cache_node *n, struct page *page,
220                                 void **list);
221 static int slab_early_init = 1;
222 
223 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
224 
225 static void kmem_cache_node_init(struct kmem_cache_node *parent)
226 {
227         INIT_LIST_HEAD(&parent->slabs_full);
228         INIT_LIST_HEAD(&parent->slabs_partial);
229         INIT_LIST_HEAD(&parent->slabs_free);
230         parent->total_slabs = 0;
231         parent->free_slabs = 0;
232         parent->shared = NULL;
233         parent->alien = NULL;
234         parent->colour_next = 0;
235         spin_lock_init(&parent->list_lock);
236         parent->free_objects = 0;
237         parent->free_touched = 0;
238 }
239 
240 #define MAKE_LIST(cachep, listp, slab, nodeid)                          \
241         do {                                                            \
242                 INIT_LIST_HEAD(listp);                                  \
243                 list_splice(&get_node(cachep, nodeid)->slab, listp);    \
244         } while (0)
245 
246 #define MAKE_ALL_LISTS(cachep, ptr, nodeid)                             \
247         do {                                                            \
248         MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid);  \
249         MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
250         MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid);  \
251         } while (0)
252 
253 #define CFLGS_OBJFREELIST_SLAB  (0x40000000UL)
254 #define CFLGS_OFF_SLAB          (0x80000000UL)
255 #define OBJFREELIST_SLAB(x)     ((x)->flags & CFLGS_OBJFREELIST_SLAB)
256 #define OFF_SLAB(x)     ((x)->flags & CFLGS_OFF_SLAB)
257 
258 #define BATCHREFILL_LIMIT       16
259 /*
260  * Optimization question: fewer reaps means less probability for unnessary
261  * cpucache drain/refill cycles.
262  *
263  * OTOH the cpuarrays can contain lots of objects,
264  * which could lock up otherwise freeable slabs.
265  */
266 #define REAPTIMEOUT_AC          (2*HZ)
267 #define REAPTIMEOUT_NODE        (4*HZ)
268 
269 #if STATS
270 #define STATS_INC_ACTIVE(x)     ((x)->num_active++)
271 #define STATS_DEC_ACTIVE(x)     ((x)->num_active--)
272 #define STATS_INC_ALLOCED(x)    ((x)->num_allocations++)
273 #define STATS_INC_GROWN(x)      ((x)->grown++)
274 #define STATS_ADD_REAPED(x,y)   ((x)->reaped += (y))
275 #define STATS_SET_HIGH(x)                                               \
276         do {                                                            \
277                 if ((x)->num_active > (x)->high_mark)                   \
278                         (x)->high_mark = (x)->num_active;               \
279         } while (0)
280 #define STATS_INC_ERR(x)        ((x)->errors++)
281 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
282 #define STATS_INC_NODEFREES(x)  ((x)->node_frees++)
283 #define STATS_INC_ACOVERFLOW(x)   ((x)->node_overflow++)
284 #define STATS_SET_FREEABLE(x, i)                                        \
285         do {                                                            \
286                 if ((x)->max_freeable < i)                              \
287                         (x)->max_freeable = i;                          \
288         } while (0)
289 #define STATS_INC_ALLOCHIT(x)   atomic_inc(&(x)->allochit)
290 #define STATS_INC_ALLOCMISS(x)  atomic_inc(&(x)->allocmiss)
291 #define STATS_INC_FREEHIT(x)    atomic_inc(&(x)->freehit)
292 #define STATS_INC_FREEMISS(x)   atomic_inc(&(x)->freemiss)
293 #else
294 #define STATS_INC_ACTIVE(x)     do { } while (0)
295 #define STATS_DEC_ACTIVE(x)     do { } while (0)
296 #define STATS_INC_ALLOCED(x)    do { } while (0)
297 #define STATS_INC_GROWN(x)      do { } while (0)
298 #define STATS_ADD_REAPED(x,y)   do { (void)(y); } while (0)
299 #define STATS_SET_HIGH(x)       do { } while (0)
300 #define STATS_INC_ERR(x)        do { } while (0)
301 #define STATS_INC_NODEALLOCS(x) do { } while (0)
302 #define STATS_INC_NODEFREES(x)  do { } while (0)
303 #define STATS_INC_ACOVERFLOW(x)   do { } while (0)
304 #define STATS_SET_FREEABLE(x, i) do { } while (0)
305 #define STATS_INC_ALLOCHIT(x)   do { } while (0)
306 #define STATS_INC_ALLOCMISS(x)  do { } while (0)
307 #define STATS_INC_FREEHIT(x)    do { } while (0)
308 #define STATS_INC_FREEMISS(x)   do { } while (0)
309 #endif
310 
311 #if DEBUG
312 
313 /*
314  * memory layout of objects:
315  * 0            : objp
316  * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
317  *              the end of an object is aligned with the end of the real
318  *              allocation. Catches writes behind the end of the allocation.
319  * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
320  *              redzone word.
321  * cachep->obj_offset: The real object.
322  * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
323  * cachep->size - 1* BYTES_PER_WORD: last caller address
324  *                                      [BYTES_PER_WORD long]
325  */
326 static int obj_offset(struct kmem_cache *cachep)
327 {
328         return cachep->obj_offset;
329 }
330 
331 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
332 {
333         BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
334         return (unsigned long long*) (objp + obj_offset(cachep) -
335                                       sizeof(unsigned long long));
336 }
337 
338 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
339 {
340         BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
341         if (cachep->flags & SLAB_STORE_USER)
342                 return (unsigned long long *)(objp + cachep->size -
343                                               sizeof(unsigned long long) -
344                                               REDZONE_ALIGN);
345         return (unsigned long long *) (objp + cachep->size -
346                                        sizeof(unsigned long long));
347 }
348 
349 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
350 {
351         BUG_ON(!(cachep->flags & SLAB_STORE_USER));
352         return (void **)(objp + cachep->size - BYTES_PER_WORD);
353 }
354 
355 #else
356 
357 #define obj_offset(x)                   0
358 #define dbg_redzone1(cachep, objp)      ({BUG(); (unsigned long long *)NULL;})
359 #define dbg_redzone2(cachep, objp)      ({BUG(); (unsigned long long *)NULL;})
360 #define dbg_userword(cachep, objp)      ({BUG(); (void **)NULL;})
361 
362 #endif
363 
364 #ifdef CONFIG_DEBUG_SLAB_LEAK
365 
366 static inline bool is_store_user_clean(struct kmem_cache *cachep)
367 {
368         return atomic_read(&cachep->store_user_clean) == 1;
369 }
370 
371 static inline void set_store_user_clean(struct kmem_cache *cachep)
372 {
373         atomic_set(&cachep->store_user_clean, 1);
374 }
375 
376 static inline void set_store_user_dirty(struct kmem_cache *cachep)
377 {
378         if (is_store_user_clean(cachep))
379                 atomic_set(&cachep->store_user_clean, 0);
380 }
381 
382 #else
383 static inline void set_store_user_dirty(struct kmem_cache *cachep) {}
384 
385 #endif
386 
387 /*
388  * Do not go above this order unless 0 objects fit into the slab or
389  * overridden on the command line.
390  */
391 #define SLAB_MAX_ORDER_HI       1
392 #define SLAB_MAX_ORDER_LO       0
393 static int slab_max_order = SLAB_MAX_ORDER_LO;
394 static bool slab_max_order_set __initdata;
395 
396 static inline struct kmem_cache *virt_to_cache(const void *obj)
397 {
398         struct page *page = virt_to_head_page(obj);
399         return page->slab_cache;
400 }
401 
402 static inline void *index_to_obj(struct kmem_cache *cache, struct page *page,
403                                  unsigned int idx)
404 {
405         return page->s_mem + cache->size * idx;
406 }
407 
408 /*
409  * We want to avoid an expensive divide : (offset / cache->size)
410  *   Using the fact that size is a constant for a particular cache,
411  *   we can replace (offset / cache->size) by
412  *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
413  */
414 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
415                                         const struct page *page, void *obj)
416 {
417         u32 offset = (obj - page->s_mem);
418         return reciprocal_divide(offset, cache->reciprocal_buffer_size);
419 }
420 
421 #define BOOT_CPUCACHE_ENTRIES   1
422 /* internal cache of cache description objs */
423 static struct kmem_cache kmem_cache_boot = {
424         .batchcount = 1,
425         .limit = BOOT_CPUCACHE_ENTRIES,
426         .shared = 1,
427         .size = sizeof(struct kmem_cache),
428         .name = "kmem_cache",
429 };
430 
431 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
432 
433 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
434 {
435         return this_cpu_ptr(cachep->cpu_cache);
436 }
437 
438 /*
439  * Calculate the number of objects and left-over bytes for a given buffer size.
440  */
441 static unsigned int cache_estimate(unsigned long gfporder, size_t buffer_size,
442                 unsigned long flags, size_t *left_over)
443 {
444         unsigned int num;
445         size_t slab_size = PAGE_SIZE << gfporder;
446 
447         /*
448          * The slab management structure can be either off the slab or
449          * on it. For the latter case, the memory allocated for a
450          * slab is used for:
451          *
452          * - @buffer_size bytes for each object
453          * - One freelist_idx_t for each object
454          *
455          * We don't need to consider alignment of freelist because
456          * freelist will be at the end of slab page. The objects will be
457          * at the correct alignment.
458          *
459          * If the slab management structure is off the slab, then the
460          * alignment will already be calculated into the size. Because
461          * the slabs are all pages aligned, the objects will be at the
462          * correct alignment when allocated.
463          */
464         if (flags & (CFLGS_OBJFREELIST_SLAB | CFLGS_OFF_SLAB)) {
465                 num = slab_size / buffer_size;
466                 *left_over = slab_size % buffer_size;
467         } else {
468                 num = slab_size / (buffer_size + sizeof(freelist_idx_t));
469                 *left_over = slab_size %
470                         (buffer_size + sizeof(freelist_idx_t));
471         }
472 
473         return num;
474 }
475 
476 #if DEBUG
477 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
478 
479 static void __slab_error(const char *function, struct kmem_cache *cachep,
480                         char *msg)
481 {
482         pr_err("slab error in %s(): cache `%s': %s\n",
483                function, cachep->name, msg);
484         dump_stack();
485         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
486 }
487 #endif
488 
489 /*
490  * By default on NUMA we use alien caches to stage the freeing of
491  * objects allocated from other nodes. This causes massive memory
492  * inefficiencies when using fake NUMA setup to split memory into a
493  * large number of small nodes, so it can be disabled on the command
494  * line
495   */
496 
497 static int use_alien_caches __read_mostly = 1;
498 static int __init noaliencache_setup(char *s)
499 {
500         use_alien_caches = 0;
501         return 1;
502 }
503 __setup("noaliencache", noaliencache_setup);
504 
505 static int __init slab_max_order_setup(char *str)
506 {
507         get_option(&str, &slab_max_order);
508         slab_max_order = slab_max_order < 0 ? 0 :
509                                 min(slab_max_order, MAX_ORDER - 1);
510         slab_max_order_set = true;
511 
512         return 1;
513 }
514 __setup("slab_max_order=", slab_max_order_setup);
515 
516 #ifdef CONFIG_NUMA
517 /*
518  * Special reaping functions for NUMA systems called from cache_reap().
519  * These take care of doing round robin flushing of alien caches (containing
520  * objects freed on different nodes from which they were allocated) and the
521  * flushing of remote pcps by calling drain_node_pages.
522  */
523 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
524 
525 static void init_reap_node(int cpu)
526 {
527         per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu),
528                                                     node_online_map);
529 }
530 
531 static void next_reap_node(void)
532 {
533         int node = __this_cpu_read(slab_reap_node);
534 
535         node = next_node_in(node, node_online_map);
536         __this_cpu_write(slab_reap_node, node);
537 }
538 
539 #else
540 #define init_reap_node(cpu) do { } while (0)
541 #define next_reap_node(void) do { } while (0)
542 #endif
543 
544 /*
545  * Initiate the reap timer running on the target CPU.  We run at around 1 to 2Hz
546  * via the workqueue/eventd.
547  * Add the CPU number into the expiration time to minimize the possibility of
548  * the CPUs getting into lockstep and contending for the global cache chain
549  * lock.
550  */
551 static void start_cpu_timer(int cpu)
552 {
553         struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
554 
555         if (reap_work->work.func == NULL) {
556                 init_reap_node(cpu);
557                 INIT_DEFERRABLE_WORK(reap_work, cache_reap);
558                 schedule_delayed_work_on(cpu, reap_work,
559                                         __round_jiffies_relative(HZ, cpu));
560         }
561 }
562 
563 static void init_arraycache(struct array_cache *ac, int limit, int batch)
564 {
565         /*
566          * The array_cache structures contain pointers to free object.
567          * However, when such objects are allocated or transferred to another
568          * cache the pointers are not cleared and they could be counted as
569          * valid references during a kmemleak scan. Therefore, kmemleak must
570          * not scan such objects.
571          */
572         kmemleak_no_scan(ac);
573         if (ac) {
574                 ac->avail = 0;
575                 ac->limit = limit;
576                 ac->batchcount = batch;
577                 ac->touched = 0;
578         }
579 }
580 
581 static struct array_cache *alloc_arraycache(int node, int entries,
582                                             int batchcount, gfp_t gfp)
583 {
584         size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache);
585         struct array_cache *ac = NULL;
586 
587         ac = kmalloc_node(memsize, gfp, node);
588         init_arraycache(ac, entries, batchcount);
589         return ac;
590 }
591 
592 static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep,
593                                         struct page *page, void *objp)
594 {
595         struct kmem_cache_node *n;
596         int page_node;
597         LIST_HEAD(list);
598 
599         page_node = page_to_nid(page);
600         n = get_node(cachep, page_node);
601 
602         spin_lock(&n->list_lock);
603         free_block(cachep, &objp, 1, page_node, &list);
604         spin_unlock(&n->list_lock);
605 
606         slabs_destroy(cachep, &list);
607 }
608 
609 /*
610  * Transfer objects in one arraycache to another.
611  * Locking must be handled by the caller.
612  *
613  * Return the number of entries transferred.
614  */
615 static int transfer_objects(struct array_cache *to,
616                 struct array_cache *from, unsigned int max)
617 {
618         /* Figure out how many entries to transfer */
619         int nr = min3(from->avail, max, to->limit - to->avail);
620 
621         if (!nr)
622                 return 0;
623 
624         memcpy(to->entry + to->avail, from->entry + from->avail -nr,
625                         sizeof(void *) *nr);
626 
627         from->avail -= nr;
628         to->avail += nr;
629         return nr;
630 }
631 
632 #ifndef CONFIG_NUMA
633 
634 #define drain_alien_cache(cachep, alien) do { } while (0)
635 #define reap_alien(cachep, n) do { } while (0)
636 
637 static inline struct alien_cache **alloc_alien_cache(int node,
638                                                 int limit, gfp_t gfp)
639 {
640         return NULL;
641 }
642 
643 static inline void free_alien_cache(struct alien_cache **ac_ptr)
644 {
645 }
646 
647 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
648 {
649         return 0;
650 }
651 
652 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
653                 gfp_t flags)
654 {
655         return NULL;
656 }
657 
658 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
659                  gfp_t flags, int nodeid)
660 {
661         return NULL;
662 }
663 
664 static inline gfp_t gfp_exact_node(gfp_t flags)
665 {
666         return flags & ~__GFP_NOFAIL;
667 }
668 
669 #else   /* CONFIG_NUMA */
670 
671 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
672 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
673 
674 static struct alien_cache *__alloc_alien_cache(int node, int entries,
675                                                 int batch, gfp_t gfp)
676 {
677         size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache);
678         struct alien_cache *alc = NULL;
679 
680         alc = kmalloc_node(memsize, gfp, node);
681         init_arraycache(&alc->ac, entries, batch);
682         spin_lock_init(&alc->lock);
683         return alc;
684 }
685 
686 static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
687 {
688         struct alien_cache **alc_ptr;
689         size_t memsize = sizeof(void *) * nr_node_ids;
690         int i;
691 
692         if (limit > 1)
693                 limit = 12;
694         alc_ptr = kzalloc_node(memsize, gfp, node);
695         if (!alc_ptr)
696                 return NULL;
697 
698         for_each_node(i) {
699                 if (i == node || !node_online(i))
700                         continue;
701                 alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp);
702                 if (!alc_ptr[i]) {
703                         for (i--; i >= 0; i--)
704                                 kfree(alc_ptr[i]);
705                         kfree(alc_ptr);
706                         return NULL;
707                 }
708         }
709         return alc_ptr;
710 }
711 
712 static void free_alien_cache(struct alien_cache **alc_ptr)
713 {
714         int i;
715 
716         if (!alc_ptr)
717                 return;
718         for_each_node(i)
719             kfree(alc_ptr[i]);
720         kfree(alc_ptr);
721 }
722 
723 static void __drain_alien_cache(struct kmem_cache *cachep,
724                                 struct array_cache *ac, int node,
725                                 struct list_head *list)
726 {
727         struct kmem_cache_node *n = get_node(cachep, node);
728 
729         if (ac->avail) {
730                 spin_lock(&n->list_lock);
731                 /*
732                  * Stuff objects into the remote nodes shared array first.
733                  * That way we could avoid the overhead of putting the objects
734                  * into the free lists and getting them back later.
735                  */
736                 if (n->shared)
737                         transfer_objects(n->shared, ac, ac->limit);
738 
739                 free_block(cachep, ac->entry, ac->avail, node, list);
740                 ac->avail = 0;
741                 spin_unlock(&n->list_lock);
742         }
743 }
744 
745 /*
746  * Called from cache_reap() to regularly drain alien caches round robin.
747  */
748 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
749 {
750         int node = __this_cpu_read(slab_reap_node);
751 
752         if (n->alien) {
753                 struct alien_cache *alc = n->alien[node];
754                 struct array_cache *ac;
755 
756                 if (alc) {
757                         ac = &alc->ac;
758                         if (ac->avail && spin_trylock_irq(&alc->lock)) {
759                                 LIST_HEAD(list);
760 
761                                 __drain_alien_cache(cachep, ac, node, &list);
762                                 spin_unlock_irq(&alc->lock);
763                                 slabs_destroy(cachep, &list);
764                         }
765                 }
766         }
767 }
768 
769 static void drain_alien_cache(struct kmem_cache *cachep,
770                                 struct alien_cache **alien)
771 {
772         int i = 0;
773         struct alien_cache *alc;
774         struct array_cache *ac;
775         unsigned long flags;
776 
777         for_each_online_node(i) {
778                 alc = alien[i];
779                 if (alc) {
780                         LIST_HEAD(list);
781 
782                         ac = &alc->ac;
783                         spin_lock_irqsave(&alc->lock, flags);
784                         __drain_alien_cache(cachep, ac, i, &list);
785                         spin_unlock_irqrestore(&alc->lock, flags);
786                         slabs_destroy(cachep, &list);
787                 }
788         }
789 }
790 
791 static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
792                                 int node, int page_node)
793 {
794         struct kmem_cache_node *n;
795         struct alien_cache *alien = NULL;
796         struct array_cache *ac;
797         LIST_HEAD(list);
798 
799         n = get_node(cachep, node);
800         STATS_INC_NODEFREES(cachep);
801         if (n->alien && n->alien[page_node]) {
802                 alien = n->alien[page_node];
803                 ac = &alien->ac;
804                 spin_lock(&alien->lock);
805                 if (unlikely(ac->avail == ac->limit)) {
806                         STATS_INC_ACOVERFLOW(cachep);
807                         __drain_alien_cache(cachep, ac, page_node, &list);
808                 }
809                 ac->entry[ac->avail++] = objp;
810                 spin_unlock(&alien->lock);
811                 slabs_destroy(cachep, &list);
812         } else {
813                 n = get_node(cachep, page_node);
814                 spin_lock(&n->list_lock);
815                 free_block(cachep, &objp, 1, page_node, &list);
816                 spin_unlock(&n->list_lock);
817                 slabs_destroy(cachep, &list);
818         }
819         return 1;
820 }
821 
822 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
823 {
824         int page_node = page_to_nid(virt_to_page(objp));
825         int node = numa_mem_id();
826         /*
827          * Make sure we are not freeing a object from another node to the array
828          * cache on this cpu.
829          */
830         if (likely(node == page_node))
831                 return 0;
832 
833         return __cache_free_alien(cachep, objp, node, page_node);
834 }
835 
836 /*
837  * Construct gfp mask to allocate from a specific node but do not reclaim or
838  * warn about failures.
839  */
840 static inline gfp_t gfp_exact_node(gfp_t flags)
841 {
842         return (flags | __GFP_THISNODE | __GFP_NOWARN) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
843 }
844 #endif
845 
846 static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp)
847 {
848         struct kmem_cache_node *n;
849 
850         /*
851          * Set up the kmem_cache_node for cpu before we can
852          * begin anything. Make sure some other cpu on this
853          * node has not already allocated this
854          */
855         n = get_node(cachep, node);
856         if (n) {
857                 spin_lock_irq(&n->list_lock);
858                 n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount +
859                                 cachep->num;
860                 spin_unlock_irq(&n->list_lock);
861 
862                 return 0;
863         }
864 
865         n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
866         if (!n)
867                 return -ENOMEM;
868 
869         kmem_cache_node_init(n);
870         n->next_reap = jiffies + REAPTIMEOUT_NODE +
871                     ((unsigned long)cachep) % REAPTIMEOUT_NODE;
872 
873         n->free_limit =
874                 (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num;
875 
876         /*
877          * The kmem_cache_nodes don't come and go as CPUs
878          * come and go.  slab_mutex is sufficient
879          * protection here.
880          */
881         cachep->node[node] = n;
882 
883         return 0;
884 }
885 
886 #if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP)
887 /*
888  * Allocates and initializes node for a node on each slab cache, used for
889  * either memory or cpu hotplug.  If memory is being hot-added, the kmem_cache_node
890  * will be allocated off-node since memory is not yet online for the new node.
891  * When hotplugging memory or a cpu, existing node are not replaced if
892  * already in use.
893  *
894  * Must hold slab_mutex.
895  */
896 static int init_cache_node_node(int node)
897 {
898         int ret;
899         struct kmem_cache *cachep;
900 
901         list_for_each_entry(cachep, &slab_caches, list) {
902                 ret = init_cache_node(cachep, node, GFP_KERNEL);
903                 if (ret)
904                         return ret;
905         }
906 
907         return 0;
908 }
909 #endif
910 
911 static int setup_kmem_cache_node(struct kmem_cache *cachep,
912                                 int node, gfp_t gfp, bool force_change)
913 {
914         int ret = -ENOMEM;
915         struct kmem_cache_node *n;
916         struct array_cache *old_shared = NULL;
917         struct array_cache *new_shared = NULL;
918         struct alien_cache **new_alien = NULL;
919         LIST_HEAD(list);
920 
921         if (use_alien_caches) {
922                 new_alien = alloc_alien_cache(node, cachep->limit, gfp);
923                 if (!new_alien)
924                         goto fail;
925         }
926 
927         if (cachep->shared) {
928                 new_shared = alloc_arraycache(node,
929                         cachep->shared * cachep->batchcount, 0xbaadf00d, gfp);
930                 if (!new_shared)
931                         goto fail;
932         }
933 
934         ret = init_cache_node(cachep, node, gfp);
935         if (ret)
936                 goto fail;
937 
938         n = get_node(cachep, node);
939         spin_lock_irq(&n->list_lock);
940         if (n->shared && force_change) {
941                 free_block(cachep, n->shared->entry,
942                                 n->shared->avail, node, &list);
943                 n->shared->avail = 0;
944         }
945 
946         if (!n->shared || force_change) {
947                 old_shared = n->shared;
948                 n->shared = new_shared;
949                 new_shared = NULL;
950         }
951 
952         if (!n->alien) {
953                 n->alien = new_alien;
954                 new_alien = NULL;
955         }
956 
957         spin_unlock_irq(&n->list_lock);
958         slabs_destroy(cachep, &list);
959 
960         /*
961          * To protect lockless access to n->shared during irq disabled context.
962          * If n->shared isn't NULL in irq disabled context, accessing to it is
963          * guaranteed to be valid until irq is re-enabled, because it will be
964          * freed after synchronize_sched().
965          */
966         if (old_shared && force_change)
967                 synchronize_sched();
968 
969 fail:
970         kfree(old_shared);
971         kfree(new_shared);
972         free_alien_cache(new_alien);
973 
974         return ret;
975 }
976 
977 #ifdef CONFIG_SMP
978 
979 static void cpuup_canceled(long cpu)
980 {
981         struct kmem_cache *cachep;
982         struct kmem_cache_node *n = NULL;
983         int node = cpu_to_mem(cpu);
984         const struct cpumask *mask = cpumask_of_node(node);
985 
986         list_for_each_entry(cachep, &slab_caches, list) {
987                 struct array_cache *nc;
988                 struct array_cache *shared;
989                 struct alien_cache **alien;
990                 LIST_HEAD(list);
991 
992                 n = get_node(cachep, node);
993                 if (!n)
994                         continue;
995 
996                 spin_lock_irq(&n->list_lock);
997 
998                 /* Free limit for this kmem_cache_node */
999                 n->free_limit -= cachep->batchcount;
1000 
1001                 /* cpu is dead; no one can alloc from it. */
1002                 nc = per_cpu_ptr(cachep->cpu_cache, cpu);
1003                 if (nc) {
1004                         free_block(cachep, nc->entry, nc->avail, node, &list);
1005                         nc->avail = 0;
1006                 }
1007 
1008                 if (!cpumask_empty(mask)) {
1009                         spin_unlock_irq(&n->list_lock);
1010                         goto free_slab;
1011                 }
1012 
1013                 shared = n->shared;
1014                 if (shared) {
1015                         free_block(cachep, shared->entry,
1016                                    shared->avail, node, &list);
1017                         n->shared = NULL;
1018                 }
1019 
1020                 alien = n->alien;
1021                 n->alien = NULL;
1022 
1023                 spin_unlock_irq(&n->list_lock);
1024 
1025                 kfree(shared);
1026                 if (alien) {
1027                         drain_alien_cache(cachep, alien);
1028                         free_alien_cache(alien);
1029                 }
1030 
1031 free_slab:
1032                 slabs_destroy(cachep, &list);
1033         }
1034         /*
1035          * In the previous loop, all the objects were freed to
1036          * the respective cache's slabs,  now we can go ahead and
1037          * shrink each nodelist to its limit.
1038          */
1039         list_for_each_entry(cachep, &slab_caches, list) {
1040                 n = get_node(cachep, node);
1041                 if (!n)
1042                         continue;
1043                 drain_freelist(cachep, n, INT_MAX);
1044         }
1045 }
1046 
1047 static int cpuup_prepare(long cpu)
1048 {
1049         struct kmem_cache *cachep;
1050         int node = cpu_to_mem(cpu);
1051         int err;
1052 
1053         /*
1054          * We need to do this right in the beginning since
1055          * alloc_arraycache's are going to use this list.
1056          * kmalloc_node allows us to add the slab to the right
1057          * kmem_cache_node and not this cpu's kmem_cache_node
1058          */
1059         err = init_cache_node_node(node);
1060         if (err < 0)
1061                 goto bad;
1062 
1063         /*
1064          * Now we can go ahead with allocating the shared arrays and
1065          * array caches
1066          */
1067         list_for_each_entry(cachep, &slab_caches, list) {
1068                 err = setup_kmem_cache_node(cachep, node, GFP_KERNEL, false);
1069                 if (err)
1070                         goto bad;
1071         }
1072 
1073         return 0;
1074 bad:
1075         cpuup_canceled(cpu);
1076         return -ENOMEM;
1077 }
1078 
1079 int slab_prepare_cpu(unsigned int cpu)
1080 {
1081         int err;
1082 
1083         mutex_lock(&slab_mutex);
1084         err = cpuup_prepare(cpu);
1085         mutex_unlock(&slab_mutex);
1086         return err;
1087 }
1088 
1089 /*
1090  * This is called for a failed online attempt and for a successful
1091  * offline.
1092  *
1093  * Even if all the cpus of a node are down, we don't free the
1094  * kmem_list3 of any cache. This to avoid a race between cpu_down, and
1095  * a kmalloc allocation from another cpu for memory from the node of
1096  * the cpu going down.  The list3 structure is usually allocated from
1097  * kmem_cache_create() and gets destroyed at kmem_cache_destroy().
1098  */
1099 int slab_dead_cpu(unsigned int cpu)
1100 {
1101         mutex_lock(&slab_mutex);
1102         cpuup_canceled(cpu);
1103         mutex_unlock(&slab_mutex);
1104         return 0;
1105 }
1106 #endif
1107 
1108 static int slab_online_cpu(unsigned int cpu)
1109 {
1110         start_cpu_timer(cpu);
1111         return 0;
1112 }
1113 
1114 static int slab_offline_cpu(unsigned int cpu)
1115 {
1116         /*
1117          * Shutdown cache reaper. Note that the slab_mutex is held so
1118          * that if cache_reap() is invoked it cannot do anything
1119          * expensive but will only modify reap_work and reschedule the
1120          * timer.
1121          */
1122         cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
1123         /* Now the cache_reaper is guaranteed to be not running. */
1124         per_cpu(slab_reap_work, cpu).work.func = NULL;
1125         return 0;
1126 }
1127 
1128 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1129 /*
1130  * Drains freelist for a node on each slab cache, used for memory hot-remove.
1131  * Returns -EBUSY if all objects cannot be drained so that the node is not
1132  * removed.
1133  *
1134  * Must hold slab_mutex.
1135  */
1136 static int __meminit drain_cache_node_node(int node)
1137 {
1138         struct kmem_cache *cachep;
1139         int ret = 0;
1140 
1141         list_for_each_entry(cachep, &slab_caches, list) {
1142                 struct kmem_cache_node *n;
1143 
1144                 n = get_node(cachep, node);
1145                 if (!n)
1146                         continue;
1147 
1148                 drain_freelist(cachep, n, INT_MAX);
1149 
1150                 if (!list_empty(&n->slabs_full) ||
1151                     !list_empty(&n->slabs_partial)) {
1152                         ret = -EBUSY;
1153                         break;
1154                 }
1155         }
1156         return ret;
1157 }
1158 
1159 static int __meminit slab_memory_callback(struct notifier_block *self,
1160                                         unsigned long action, void *arg)
1161 {
1162         struct memory_notify *mnb = arg;
1163         int ret = 0;
1164         int nid;
1165 
1166         nid = mnb->status_change_nid;
1167         if (nid < 0)
1168                 goto out;
1169 
1170         switch (action) {
1171         case MEM_GOING_ONLINE:
1172                 mutex_lock(&slab_mutex);
1173                 ret = init_cache_node_node(nid);
1174                 mutex_unlock(&slab_mutex);
1175                 break;
1176         case MEM_GOING_OFFLINE:
1177                 mutex_lock(&slab_mutex);
1178                 ret = drain_cache_node_node(nid);
1179                 mutex_unlock(&slab_mutex);
1180                 break;
1181         case MEM_ONLINE:
1182         case MEM_OFFLINE:
1183         case MEM_CANCEL_ONLINE:
1184         case MEM_CANCEL_OFFLINE:
1185                 break;
1186         }
1187 out:
1188         return notifier_from_errno(ret);
1189 }
1190 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1191 
1192 /*
1193  * swap the static kmem_cache_node with kmalloced memory
1194  */
1195 static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list,
1196                                 int nodeid)
1197 {
1198         struct kmem_cache_node *ptr;
1199 
1200         ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid);
1201         BUG_ON(!ptr);
1202 
1203         memcpy(ptr, list, sizeof(struct kmem_cache_node));
1204         /*
1205          * Do not assume that spinlocks can be initialized via memcpy:
1206          */
1207         spin_lock_init(&ptr->list_lock);
1208 
1209         MAKE_ALL_LISTS(cachep, ptr, nodeid);
1210         cachep->node[nodeid] = ptr;
1211 }
1212 
1213 /*
1214  * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1215  * size of kmem_cache_node.
1216  */
1217 static void __init set_up_node(struct kmem_cache *cachep, int index)
1218 {
1219         int node;
1220 
1221         for_each_online_node(node) {
1222                 cachep->node[node] = &init_kmem_cache_node[index + node];
1223                 cachep->node[node]->next_reap = jiffies +
1224                     REAPTIMEOUT_NODE +
1225                     ((unsigned long)cachep) % REAPTIMEOUT_NODE;
1226         }
1227 }
1228 
1229 /*
1230  * Initialisation.  Called after the page allocator have been initialised and
1231  * before smp_init().
1232  */
1233 void __init kmem_cache_init(void)
1234 {
1235         int i;
1236 
1237         BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) <
1238                                         sizeof(struct rcu_head));
1239         kmem_cache = &kmem_cache_boot;
1240 
1241         if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1)
1242                 use_alien_caches = 0;
1243 
1244         for (i = 0; i < NUM_INIT_LISTS; i++)
1245                 kmem_cache_node_init(&init_kmem_cache_node[i]);
1246 
1247         /*
1248          * Fragmentation resistance on low memory - only use bigger
1249          * page orders on machines with more than 32MB of memory if
1250          * not overridden on the command line.
1251          */
1252         if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
1253                 slab_max_order = SLAB_MAX_ORDER_HI;
1254 
1255         /* Bootstrap is tricky, because several objects are allocated
1256          * from caches that do not exist yet:
1257          * 1) initialize the kmem_cache cache: it contains the struct
1258          *    kmem_cache structures of all caches, except kmem_cache itself:
1259          *    kmem_cache is statically allocated.
1260          *    Initially an __init data area is used for the head array and the
1261          *    kmem_cache_node structures, it's replaced with a kmalloc allocated
1262          *    array at the end of the bootstrap.
1263          * 2) Create the first kmalloc cache.
1264          *    The struct kmem_cache for the new cache is allocated normally.
1265          *    An __init data area is used for the head array.
1266          * 3) Create the remaining kmalloc caches, with minimally sized
1267          *    head arrays.
1268          * 4) Replace the __init data head arrays for kmem_cache and the first
1269          *    kmalloc cache with kmalloc allocated arrays.
1270          * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1271          *    the other cache's with kmalloc allocated memory.
1272          * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1273          */
1274 
1275         /* 1) create the kmem_cache */
1276 
1277         /*
1278          * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1279          */
1280         create_boot_cache(kmem_cache, "kmem_cache",
1281                 offsetof(struct kmem_cache, node) +
1282                                   nr_node_ids * sizeof(struct kmem_cache_node *),
1283                                   SLAB_HWCACHE_ALIGN);
1284         list_add(&kmem_cache->list, &slab_caches);
1285         slab_state = PARTIAL;
1286 
1287         /*
1288          * Initialize the caches that provide memory for the  kmem_cache_node
1289          * structures first.  Without this, further allocations will bug.
1290          */
1291         kmalloc_caches[INDEX_NODE] = create_kmalloc_cache("kmalloc-node",
1292                                 kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS);
1293         slab_state = PARTIAL_NODE;
1294         setup_kmalloc_cache_index_table();
1295 
1296         slab_early_init = 0;
1297 
1298         /* 5) Replace the bootstrap kmem_cache_node */
1299         {
1300                 int nid;
1301 
1302                 for_each_online_node(nid) {
1303                         init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid);
1304 
1305                         init_list(kmalloc_caches[INDEX_NODE],
1306                                           &init_kmem_cache_node[SIZE_NODE + nid], nid);
1307                 }
1308         }
1309 
1310         create_kmalloc_caches(ARCH_KMALLOC_FLAGS);
1311 }
1312 
1313 void __init kmem_cache_init_late(void)
1314 {
1315         struct kmem_cache *cachep;
1316 
1317         slab_state = UP;
1318 
1319         /* 6) resize the head arrays to their final sizes */
1320         mutex_lock(&slab_mutex);
1321         list_for_each_entry(cachep, &slab_caches, list)
1322                 if (enable_cpucache(cachep, GFP_NOWAIT))
1323                         BUG();
1324         mutex_unlock(&slab_mutex);
1325 
1326         /* Done! */
1327         slab_state = FULL;
1328 
1329 #ifdef CONFIG_NUMA
1330         /*
1331          * Register a memory hotplug callback that initializes and frees
1332          * node.
1333          */
1334         hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
1335 #endif
1336 
1337         /*
1338          * The reap timers are started later, with a module init call: That part
1339          * of the kernel is not yet operational.
1340          */
1341 }
1342 
1343 static int __init cpucache_init(void)
1344 {
1345         int ret;
1346 
1347         /*
1348          * Register the timers that return unneeded pages to the page allocator
1349          */
1350         ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SLAB online",
1351                                 slab_online_cpu, slab_offline_cpu);
1352         WARN_ON(ret < 0);
1353 
1354         /* Done! */
1355         slab_state = FULL;
1356         return 0;
1357 }
1358 __initcall(cpucache_init);
1359 
1360 static noinline void
1361 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
1362 {
1363 #if DEBUG
1364         struct kmem_cache_node *n;
1365         unsigned long flags;
1366         int node;
1367         static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
1368                                       DEFAULT_RATELIMIT_BURST);
1369 
1370         if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs))
1371                 return;
1372 
1373         pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
1374                 nodeid, gfpflags, &gfpflags);
1375         pr_warn("  cache: %s, object size: %d, order: %d\n",
1376                 cachep->name, cachep->size, cachep->gfporder);
1377 
1378         for_each_kmem_cache_node(cachep, node, n) {
1379                 unsigned long total_slabs, free_slabs, free_objs;
1380 
1381                 spin_lock_irqsave(&n->list_lock, flags);
1382                 total_slabs = n->total_slabs;
1383                 free_slabs = n->free_slabs;
1384                 free_objs = n->free_objects;
1385                 spin_unlock_irqrestore(&n->list_lock, flags);
1386 
1387                 pr_warn("  node %d: slabs: %ld/%ld, objs: %ld/%ld\n",
1388                         node, total_slabs - free_slabs, total_slabs,
1389                         (total_slabs * cachep->num) - free_objs,
1390                         total_slabs * cachep->num);
1391         }
1392 #endif
1393 }
1394 
1395 /*
1396  * Interface to system's page allocator. No need to hold the
1397  * kmem_cache_node ->list_lock.
1398  *
1399  * If we requested dmaable memory, we will get it. Even if we
1400  * did not request dmaable memory, we might get it, but that
1401  * would be relatively rare and ignorable.
1402  */
1403 static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
1404                                                                 int nodeid)
1405 {
1406         struct page *page;
1407         int nr_pages;
1408 
1409         flags |= cachep->allocflags;
1410         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1411                 flags |= __GFP_RECLAIMABLE;
1412 
1413         page = __alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
1414         if (!page) {
1415                 slab_out_of_memory(cachep, flags, nodeid);
1416                 return NULL;
1417         }
1418 
1419         if (memcg_charge_slab(page, flags, cachep->gfporder, cachep)) {
1420                 __free_pages(page, cachep->gfporder);
1421                 return NULL;
1422         }
1423 
1424         nr_pages = (1 << cachep->gfporder);
1425         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1426                 add_zone_page_state(page_zone(page),
1427                         NR_SLAB_RECLAIMABLE, nr_pages);
1428         else
1429                 add_zone_page_state(page_zone(page),
1430                         NR_SLAB_UNRECLAIMABLE, nr_pages);
1431 
1432         __SetPageSlab(page);
1433         /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1434         if (sk_memalloc_socks() && page_is_pfmemalloc(page))
1435                 SetPageSlabPfmemalloc(page);
1436 
1437         if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
1438                 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
1439 
1440                 if (cachep->ctor)
1441                         kmemcheck_mark_uninitialized_pages(page, nr_pages);
1442                 else
1443                         kmemcheck_mark_unallocated_pages(page, nr_pages);
1444         }
1445 
1446         return page;
1447 }
1448 
1449 /*
1450  * Interface to system's page release.
1451  */
1452 static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
1453 {
1454         int order = cachep->gfporder;
1455         unsigned long nr_freed = (1 << order);
1456 
1457         kmemcheck_free_shadow(page, order);
1458 
1459         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
1460                 sub_zone_page_state(page_zone(page),
1461                                 NR_SLAB_RECLAIMABLE, nr_freed);
1462         else
1463                 sub_zone_page_state(page_zone(page),
1464                                 NR_SLAB_UNRECLAIMABLE, nr_freed);
1465 
1466         BUG_ON(!PageSlab(page));
1467         __ClearPageSlabPfmemalloc(page);
1468         __ClearPageSlab(page);
1469         page_mapcount_reset(page);
1470         page->mapping = NULL;
1471 
1472         if (current->reclaim_state)
1473                 current->reclaim_state->reclaimed_slab += nr_freed;
1474         memcg_uncharge_slab(page, order, cachep);
1475         __free_pages(page, order);
1476 }
1477 
1478 static void kmem_rcu_free(struct rcu_head *head)
1479 {
1480         struct kmem_cache *cachep;
1481         struct page *page;
1482 
1483         page = container_of(head, struct page, rcu_head);
1484         cachep = page->slab_cache;
1485 
1486         kmem_freepages(cachep, page);
1487 }
1488 
1489 #if DEBUG
1490 static bool is_debug_pagealloc_cache(struct kmem_cache *cachep)
1491 {
1492         if (debug_pagealloc_enabled() && OFF_SLAB(cachep) &&
1493                 (cachep->size % PAGE_SIZE) == 0)
1494                 return true;
1495 
1496         return false;
1497 }
1498 
1499 #ifdef CONFIG_DEBUG_PAGEALLOC
1500 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
1501                             unsigned long caller)
1502 {
1503         int size = cachep->object_size;
1504 
1505         addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
1506 
1507         if (size < 5 * sizeof(unsigned long))
1508                 return;
1509 
1510         *addr++ = 0x12345678;
1511         *addr++ = caller;
1512         *addr++ = smp_processor_id();
1513         size -= 3 * sizeof(unsigned long);
1514         {
1515                 unsigned long *sptr = &caller;
1516                 unsigned long svalue;
1517 
1518                 while (!kstack_end(sptr)) {
1519                         svalue = *sptr++;
1520                         if (kernel_text_address(svalue)) {
1521                                 *addr++ = svalue;
1522                                 size -= sizeof(unsigned long);
1523                                 if (size <= sizeof(unsigned long))
1524                                         break;
1525                         }
1526                 }
1527 
1528         }
1529         *addr++ = 0x87654321;
1530 }
1531 
1532 static void slab_kernel_map(struct kmem_cache *cachep, void *objp,
1533                                 int map, unsigned long caller)
1534 {
1535         if (!is_debug_pagealloc_cache(cachep))
1536                 return;
1537 
1538         if (caller)
1539                 store_stackinfo(cachep, objp, caller);
1540 
1541         kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map);
1542 }
1543 
1544 #else
1545 static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp,
1546                                 int map, unsigned long caller) {}
1547 
1548 #endif
1549 
1550 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1551 {
1552         int size = cachep->object_size;
1553         addr = &((char *)addr)[obj_offset(cachep)];
1554 
1555         memset(addr, val, size);
1556         *(unsigned char *)(addr + size - 1) = POISON_END;
1557 }
1558 
1559 static void dump_line(char *data, int offset, int limit)
1560 {
1561         int i;
1562         unsigned char error = 0;
1563         int bad_count = 0;
1564 
1565         pr_err("%03x: ", offset);
1566         for (i = 0; i < limit; i++) {
1567                 if (data[offset + i] != POISON_FREE) {
1568                         error = data[offset + i];
1569                         bad_count++;
1570                 }
1571         }
1572         print_hex_dump(KERN_CONT, "", 0, 16, 1,
1573                         &data[offset], limit, 1);
1574 
1575         if (bad_count == 1) {
1576                 error ^= POISON_FREE;
1577                 if (!(error & (error - 1))) {
1578                         pr_err("Single bit error detected. Probably bad RAM.\n");
1579 #ifdef CONFIG_X86
1580                         pr_err("Run memtest86+ or a similar memory test tool.\n");
1581 #else
1582                         pr_err("Run a memory test tool.\n");
1583 #endif
1584                 }
1585         }
1586 }
1587 #endif
1588 
1589 #if DEBUG
1590 
1591 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1592 {
1593         int i, size;
1594         char *realobj;
1595 
1596         if (cachep->flags & SLAB_RED_ZONE) {
1597                 pr_err("Redzone: 0x%llx/0x%llx\n",
1598                        *dbg_redzone1(cachep, objp),
1599                        *dbg_redzone2(cachep, objp));
1600         }
1601 
1602         if (cachep->flags & SLAB_STORE_USER) {
1603                 pr_err("Last user: [<%p>](%pSR)\n",
1604                        *dbg_userword(cachep, objp),
1605                        *dbg_userword(cachep, objp));
1606         }
1607         realobj = (char *)objp + obj_offset(cachep);
1608         size = cachep->object_size;
1609         for (i = 0; i < size && lines; i += 16, lines--) {
1610                 int limit;
1611                 limit = 16;
1612                 if (i + limit > size)
1613                         limit = size - i;
1614                 dump_line(realobj, i, limit);
1615         }
1616 }
1617 
1618 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1619 {
1620         char *realobj;
1621         int size, i;
1622         int lines = 0;
1623 
1624         if (is_debug_pagealloc_cache(cachep))
1625                 return;
1626 
1627         realobj = (char *)objp + obj_offset(cachep);
1628         size = cachep->object_size;
1629 
1630         for (i = 0; i < size; i++) {
1631                 char exp = POISON_FREE;
1632                 if (i == size - 1)
1633                         exp = POISON_END;
1634                 if (realobj[i] != exp) {
1635                         int limit;
1636                         /* Mismatch ! */
1637                         /* Print header */
1638                         if (lines == 0) {
1639                                 pr_err("Slab corruption (%s): %s start=%p, len=%d\n",
1640                                        print_tainted(), cachep->name,
1641                                        realobj, size);
1642                                 print_objinfo(cachep, objp, 0);
1643                         }
1644                         /* Hexdump the affected line */
1645                         i = (i / 16) * 16;
1646                         limit = 16;
1647                         if (i + limit > size)
1648                                 limit = size - i;
1649                         dump_line(realobj, i, limit);
1650                         i += 16;
1651                         lines++;
1652                         /* Limit to 5 lines */
1653                         if (lines > 5)
1654                                 break;
1655                 }
1656         }
1657         if (lines != 0) {
1658                 /* Print some data about the neighboring objects, if they
1659                  * exist:
1660                  */
1661                 struct page *page = virt_to_head_page(objp);
1662                 unsigned int objnr;
1663 
1664                 objnr = obj_to_index(cachep, page, objp);
1665                 if (objnr) {
1666                         objp = index_to_obj(cachep, page, objnr - 1);
1667                         realobj = (char *)objp + obj_offset(cachep);
1668                         pr_err("Prev obj: start=%p, len=%d\n", realobj, size);
1669                         print_objinfo(cachep, objp, 2);
1670                 }
1671                 if (objnr + 1 < cachep->num) {
1672                         objp = index_to_obj(cachep, page, objnr + 1);
1673                         realobj = (char *)objp + obj_offset(cachep);
1674                         pr_err("Next obj: start=%p, len=%d\n", realobj, size);
1675                         print_objinfo(cachep, objp, 2);
1676                 }
1677         }
1678 }
1679 #endif
1680 
1681 #if DEBUG
1682 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1683                                                 struct page *page)
1684 {
1685         int i;
1686 
1687         if (OBJFREELIST_SLAB(cachep) && cachep->flags & SLAB_POISON) {
1688                 poison_obj(cachep, page->freelist - obj_offset(cachep),
1689                         POISON_FREE);
1690         }
1691 
1692         for (i = 0; i < cachep->num; i++) {
1693                 void *objp = index_to_obj(cachep, page, i);
1694 
1695                 if (cachep->flags & SLAB_POISON) {
1696                         check_poison_obj(cachep, objp);
1697                         slab_kernel_map(cachep, objp, 1, 0);
1698                 }
1699                 if (cachep->flags & SLAB_RED_ZONE) {
1700                         if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1701                                 slab_error(cachep, "start of a freed object was overwritten");
1702                         if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1703                                 slab_error(cachep, "end of a freed object was overwritten");
1704                 }
1705         }
1706 }
1707 #else
1708 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1709                                                 struct page *page)
1710 {
1711 }
1712 #endif
1713 
1714 /**
1715  * slab_destroy - destroy and release all objects in a slab
1716  * @cachep: cache pointer being destroyed
1717  * @page: page pointer being destroyed
1718  *
1719  * Destroy all the objs in a slab page, and release the mem back to the system.
1720  * Before calling the slab page must have been unlinked from the cache. The
1721  * kmem_cache_node ->list_lock is not held/needed.
1722  */
1723 static void slab_destroy(struct kmem_cache *cachep, struct page *page)
1724 {
1725         void *freelist;
1726 
1727         freelist = page->freelist;
1728         slab_destroy_debugcheck(cachep, page);
1729         if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
1730                 call_rcu(&page->rcu_head, kmem_rcu_free);
1731         else
1732                 kmem_freepages(cachep, page);
1733 
1734         /*
1735          * From now on, we don't use freelist
1736          * although actual page can be freed in rcu context
1737          */
1738         if (OFF_SLAB(cachep))
1739                 kmem_cache_free(cachep->freelist_cache, freelist);
1740 }
1741 
1742 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list)
1743 {
1744         struct page *page, *n;
1745 
1746         list_for_each_entry_safe(page, n, list, lru) {
1747                 list_del(&page->lru);
1748                 slab_destroy(cachep, page);
1749         }
1750 }
1751 
1752 /**
1753  * calculate_slab_order - calculate size (page order) of slabs
1754  * @cachep: pointer to the cache that is being created
1755  * @size: size of objects to be created in this cache.
1756  * @flags: slab allocation flags
1757  *
1758  * Also calculates the number of objects per slab.
1759  *
1760  * This could be made much more intelligent.  For now, try to avoid using
1761  * high order pages for slabs.  When the gfp() functions are more friendly
1762  * towards high-order requests, this should be changed.
1763  */
1764 static size_t calculate_slab_order(struct kmem_cache *cachep,
1765                                 size_t size, unsigned long flags)
1766 {
1767         size_t left_over = 0;
1768         int gfporder;
1769 
1770         for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
1771                 unsigned int num;
1772                 size_t remainder;
1773 
1774                 num = cache_estimate(gfporder, size, flags, &remainder);
1775                 if (!num)
1776                         continue;
1777 
1778                 /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */
1779                 if (num > SLAB_OBJ_MAX_NUM)
1780                         break;
1781 
1782                 if (flags & CFLGS_OFF_SLAB) {
1783                         struct kmem_cache *freelist_cache;
1784                         size_t freelist_size;
1785 
1786                         freelist_size = num * sizeof(freelist_idx_t);
1787                         freelist_cache = kmalloc_slab(freelist_size, 0u);
1788                         if (!freelist_cache)
1789                                 continue;
1790 
1791                         /*
1792                          * Needed to avoid possible looping condition
1793                          * in cache_grow_begin()
1794                          */
1795                         if (OFF_SLAB(freelist_cache))
1796                                 continue;
1797 
1798                         /* check if off slab has enough benefit */
1799                         if (freelist_cache->size > cachep->size / 2)
1800                                 continue;
1801                 }
1802 
1803                 /* Found something acceptable - save it away */
1804                 cachep->num = num;
1805                 cachep->gfporder = gfporder;
1806                 left_over = remainder;
1807 
1808                 /*
1809                  * A VFS-reclaimable slab tends to have most allocations
1810                  * as GFP_NOFS and we really don't want to have to be allocating
1811                  * higher-order pages when we are unable to shrink dcache.
1812                  */
1813                 if (flags & SLAB_RECLAIM_ACCOUNT)
1814                         break;
1815 
1816                 /*
1817                  * Large number of objects is good, but very large slabs are
1818                  * currently bad for the gfp()s.
1819                  */
1820                 if (gfporder >= slab_max_order)
1821                         break;
1822 
1823                 /*
1824                  * Acceptable internal fragmentation?
1825                  */
1826                 if (left_over * 8 <= (PAGE_SIZE << gfporder))
1827                         break;
1828         }
1829         return left_over;
1830 }
1831 
1832 static struct array_cache __percpu *alloc_kmem_cache_cpus(
1833                 struct kmem_cache *cachep, int entries, int batchcount)
1834 {
1835         int cpu;
1836         size_t size;
1837         struct array_cache __percpu *cpu_cache;
1838 
1839         size = sizeof(void *) * entries + sizeof(struct array_cache);
1840         cpu_cache = __alloc_percpu(size, sizeof(void *));
1841 
1842         if (!cpu_cache)
1843                 return NULL;
1844 
1845         for_each_possible_cpu(cpu) {
1846                 init_arraycache(per_cpu_ptr(cpu_cache, cpu),
1847                                 entries, batchcount);
1848         }
1849 
1850         return cpu_cache;
1851 }
1852 
1853 static int __ref setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
1854 {
1855         if (slab_state >= FULL)
1856                 return enable_cpucache(cachep, gfp);
1857 
1858         cachep->cpu_cache = alloc_kmem_cache_cpus(cachep, 1, 1);
1859         if (!cachep->cpu_cache)
1860                 return 1;
1861 
1862         if (slab_state == DOWN) {
1863                 /* Creation of first cache (kmem_cache). */
1864                 set_up_node(kmem_cache, CACHE_CACHE);
1865         } else if (slab_state == PARTIAL) {
1866                 /* For kmem_cache_node */
1867                 set_up_node(cachep, SIZE_NODE);
1868         } else {
1869                 int node;
1870 
1871                 for_each_online_node(node) {
1872                         cachep->node[node] = kmalloc_node(
1873                                 sizeof(struct kmem_cache_node), gfp, node);
1874                         BUG_ON(!cachep->node[node]);
1875                         kmem_cache_node_init(cachep->node[node]);
1876                 }
1877         }
1878 
1879         cachep->node[numa_mem_id()]->next_reap =
1880                         jiffies + REAPTIMEOUT_NODE +
1881                         ((unsigned long)cachep) % REAPTIMEOUT_NODE;
1882 
1883         cpu_cache_get(cachep)->avail = 0;
1884         cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
1885         cpu_cache_get(cachep)->batchcount = 1;
1886         cpu_cache_get(cachep)->touched = 0;
1887         cachep->batchcount = 1;
1888         cachep->limit = BOOT_CPUCACHE_ENTRIES;
1889         return 0;
1890 }
1891 
1892 unsigned long kmem_cache_flags(unsigned long object_size,
1893         unsigned long flags, const char *name,
1894         void (*ctor)(void *))
1895 {
1896         return flags;
1897 }
1898 
1899 struct kmem_cache *
1900 __kmem_cache_alias(const char *name, size_t size, size_t align,
1901                    unsigned long flags, void (*ctor)(void *))
1902 {
1903         struct kmem_cache *cachep;
1904 
1905         cachep = find_mergeable(size, align, flags, name, ctor);
1906         if (cachep) {
1907                 cachep->refcount++;
1908 
1909                 /*
1910                  * Adjust the object sizes so that we clear
1911                  * the complete object on kzalloc.
1912                  */
1913                 cachep->object_size = max_t(int, cachep->object_size, size);
1914         }
1915         return cachep;
1916 }
1917 
1918 static bool set_objfreelist_slab_cache(struct kmem_cache *cachep,
1919                         size_t size, unsigned long flags)
1920 {
1921         size_t left;
1922 
1923         cachep->num = 0;
1924 
1925         if (cachep->ctor || flags & SLAB_DESTROY_BY_RCU)
1926                 return false;
1927 
1928         left = calculate_slab_order(cachep, size,
1929                         flags | CFLGS_OBJFREELIST_SLAB);
1930         if (!cachep->num)
1931                 return false;
1932 
1933         if (cachep->num * sizeof(freelist_idx_t) > cachep->object_size)
1934                 return false;
1935 
1936         cachep->colour = left / cachep->colour_off;
1937 
1938         return true;
1939 }
1940 
1941 static bool set_off_slab_cache(struct kmem_cache *cachep,
1942                         size_t size, unsigned long flags)
1943 {
1944         size_t left;
1945 
1946         cachep->num = 0;
1947 
1948         /*
1949          * Always use on-slab management when SLAB_NOLEAKTRACE
1950          * to avoid recursive calls into kmemleak.
1951          */
1952         if (flags & SLAB_NOLEAKTRACE)
1953                 return false;
1954 
1955         /*
1956          * Size is large, assume best to place the slab management obj
1957          * off-slab (should allow better packing of objs).
1958          */
1959         left = calculate_slab_order(cachep, size, flags | CFLGS_OFF_SLAB);
1960         if (!cachep->num)
1961                 return false;
1962 
1963         /*
1964          * If the slab has been placed off-slab, and we have enough space then
1965          * move it on-slab. This is at the expense of any extra colouring.
1966          */
1967         if (left >= cachep->num * sizeof(freelist_idx_t))
1968                 return false;
1969 
1970         cachep->colour = left / cachep->colour_off;
1971 
1972         return true;
1973 }
1974 
1975 static bool set_on_slab_cache(struct kmem_cache *cachep,
1976                         size_t size, unsigned long flags)
1977 {
1978         size_t left;
1979 
1980         cachep->num = 0;
1981 
1982         left = calculate_slab_order(cachep, size, flags);
1983         if (!cachep->num)
1984                 return false;
1985 
1986         cachep->colour = left / cachep->colour_off;
1987 
1988         return true;
1989 }
1990 
1991 /**
1992  * __kmem_cache_create - Create a cache.
1993  * @cachep: cache management descriptor
1994  * @flags: SLAB flags
1995  *
1996  * Returns a ptr to the cache on success, NULL on failure.
1997  * Cannot be called within a int, but can be interrupted.
1998  * The @ctor is run when new pages are allocated by the cache.
1999  *
2000  * The flags are
2001  *
2002  * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
2003  * to catch references to uninitialised memory.
2004  *
2005  * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
2006  * for buffer overruns.
2007  *
2008  * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
2009  * cacheline.  This can be beneficial if you're counting cycles as closely
2010  * as davem.
2011  */
2012 int
2013 __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
2014 {
2015         size_t ralign = BYTES_PER_WORD;
2016         gfp_t gfp;
2017         int err;
2018         size_t size = cachep->size;
2019 
2020 #if DEBUG
2021 #if FORCED_DEBUG
2022         /*
2023          * Enable redzoning and last user accounting, except for caches with
2024          * large objects, if the increased size would increase the object size
2025          * above the next power of two: caches with object sizes just above a
2026          * power of two have a significant amount of internal fragmentation.
2027          */
2028         if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
2029                                                 2 * sizeof(unsigned long long)))
2030                 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
2031         if (!(flags & SLAB_DESTROY_BY_RCU))
2032                 flags |= SLAB_POISON;
2033 #endif
2034 #endif
2035 
2036         /*
2037          * Check that size is in terms of words.  This is needed to avoid
2038          * unaligned accesses for some archs when redzoning is used, and makes
2039          * sure any on-slab bufctl's are also correctly aligned.
2040          */
2041         if (size & (BYTES_PER_WORD - 1)) {
2042                 size += (BYTES_PER_WORD - 1);
2043                 size &= ~(BYTES_PER_WORD - 1);
2044         }
2045 
2046         if (flags & SLAB_RED_ZONE) {
2047                 ralign = REDZONE_ALIGN;
2048                 /* If redzoning, ensure that the second redzone is suitably
2049                  * aligned, by adjusting the object size accordingly. */
2050                 size += REDZONE_ALIGN - 1;
2051                 size &= ~(REDZONE_ALIGN - 1);
2052         }
2053 
2054         /* 3) caller mandated alignment */
2055         if (ralign < cachep->align) {
2056                 ralign = cachep->align;
2057         }
2058         /* disable debug if necessary */
2059         if (ralign > __alignof__(unsigned long long))
2060                 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2061         /*
2062          * 4) Store it.
2063          */
2064         cachep->align = ralign;
2065         cachep->colour_off = cache_line_size();
2066         /* Offset must be a multiple of the alignment. */
2067         if (cachep->colour_off < cachep->align)
2068                 cachep->colour_off = cachep->align;
2069 
2070         if (slab_is_available())
2071                 gfp = GFP_KERNEL;
2072         else
2073                 gfp = GFP_NOWAIT;
2074 
2075 #if DEBUG
2076 
2077         /*
2078          * Both debugging options require word-alignment which is calculated
2079          * into align above.
2080          */
2081         if (flags & SLAB_RED_ZONE) {
2082                 /* add space for red zone words */
2083                 cachep->obj_offset += sizeof(unsigned long long);
2084                 size += 2 * sizeof(unsigned long long);
2085         }
2086         if (flags & SLAB_STORE_USER) {
2087                 /* user store requires one word storage behind the end of
2088                  * the real object. But if the second red zone needs to be
2089                  * aligned to 64 bits, we must allow that much space.
2090                  */
2091                 if (flags & SLAB_RED_ZONE)
2092                         size += REDZONE_ALIGN;
2093                 else
2094                         size += BYTES_PER_WORD;
2095         }
2096 #endif
2097 
2098         kasan_cache_create(cachep, &size, &flags);
2099 
2100         size = ALIGN(size, cachep->align);
2101         /*
2102          * We should restrict the number of objects in a slab to implement
2103          * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition.
2104          */
2105         if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE)
2106                 size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align);
2107 
2108 #if DEBUG
2109         /*
2110          * To activate debug pagealloc, off-slab management is necessary
2111          * requirement. In early phase of initialization, small sized slab
2112          * doesn't get initialized so it would not be possible. So, we need
2113          * to check size >= 256. It guarantees that all necessary small
2114          * sized slab is initialized in current slab initialization sequence.
2115          */
2116         if (debug_pagealloc_enabled() && (flags & SLAB_POISON) &&
2117                 size >= 256 && cachep->object_size > cache_line_size()) {
2118                 if (size < PAGE_SIZE || size % PAGE_SIZE == 0) {
2119                         size_t tmp_size = ALIGN(size, PAGE_SIZE);
2120 
2121                         if (set_off_slab_cache(cachep, tmp_size, flags)) {
2122                                 flags |= CFLGS_OFF_SLAB;
2123                                 cachep->obj_offset += tmp_size - size;
2124                                 size = tmp_size;
2125                                 goto done;
2126                         }
2127                 }
2128         }
2129 #endif
2130 
2131         if (set_objfreelist_slab_cache(cachep, size, flags)) {
2132                 flags |= CFLGS_OBJFREELIST_SLAB;
2133                 goto done;
2134         }
2135 
2136         if (set_off_slab_cache(cachep, size, flags)) {
2137                 flags |= CFLGS_OFF_SLAB;
2138                 goto done;
2139         }
2140 
2141         if (set_on_slab_cache(cachep, size, flags))
2142                 goto done;
2143 
2144         return -E2BIG;
2145 
2146 done:
2147         cachep->freelist_size = cachep->num * sizeof(freelist_idx_t);
2148         cachep->flags = flags;
2149         cachep->allocflags = __GFP_COMP;
2150         if (flags & SLAB_CACHE_DMA)
2151                 cachep->allocflags |= GFP_DMA;
2152         cachep->size = size;
2153         cachep->reciprocal_buffer_size = reciprocal_value(size);
2154 
2155 #if DEBUG
2156         /*
2157          * If we're going to use the generic kernel_map_pages()
2158          * poisoning, then it's going to smash the contents of
2159          * the redzone and userword anyhow, so switch them off.
2160          */
2161         if (IS_ENABLED(CONFIG_PAGE_POISONING) &&
2162                 (cachep->flags & SLAB_POISON) &&
2163                 is_debug_pagealloc_cache(cachep))
2164                 cachep->flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2165 #endif
2166 
2167         if (OFF_SLAB(cachep)) {
2168                 cachep->freelist_cache =
2169                         kmalloc_slab(cachep->freelist_size, 0u);
2170         }
2171 
2172         err = setup_cpu_cache(cachep, gfp);
2173         if (err) {
2174                 __kmem_cache_release(cachep);
2175                 return err;
2176         }
2177 
2178         return 0;
2179 }
2180 
2181 #if DEBUG
2182 static void check_irq_off(void)
2183 {
2184         BUG_ON(!irqs_disabled());
2185 }
2186 
2187 static void check_irq_on(void)
2188 {
2189         BUG_ON(irqs_disabled());
2190 }
2191 
2192 static void check_mutex_acquired(void)
2193 {
2194         BUG_ON(!mutex_is_locked(&slab_mutex));
2195 }
2196 
2197 static void check_spinlock_acquired(struct kmem_cache *cachep)
2198 {
2199 #ifdef CONFIG_SMP
2200         check_irq_off();
2201         assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock);
2202 #endif
2203 }
2204 
2205 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2206 {
2207 #ifdef CONFIG_SMP
2208         check_irq_off();
2209         assert_spin_locked(&get_node(cachep, node)->list_lock);
2210 #endif
2211 }
2212 
2213 #else
2214 #define check_irq_off() do { } while(0)
2215 #define check_irq_on()  do { } while(0)
2216 #define check_mutex_acquired()  do { } while(0)
2217 #define check_spinlock_acquired(x) do { } while(0)
2218 #define check_spinlock_acquired_node(x, y) do { } while(0)
2219 #endif
2220 
2221 static void drain_array_locked(struct kmem_cache *cachep, struct array_cache *ac,
2222                                 int node, bool free_all, struct list_head *list)
2223 {
2224         int tofree;
2225 
2226         if (!ac || !ac->avail)
2227                 return;
2228 
2229         tofree = free_all ? ac->avail : (ac->limit + 4) / 5;
2230         if (tofree > ac->avail)
2231                 tofree = (ac->avail + 1) / 2;
2232 
2233         free_block(cachep, ac->entry, tofree, node, list);
2234         ac->avail -= tofree;
2235         memmove(ac->entry, &(ac->entry[tofree]), sizeof(void *) * ac->avail);
2236 }
2237 
2238 static void do_drain(void *arg)
2239 {
2240         struct kmem_cache *cachep = arg;
2241         struct array_cache *ac;
2242         int node = numa_mem_id();
2243         struct kmem_cache_node *n;
2244         LIST_HEAD(list);
2245 
2246         check_irq_off();
2247         ac = cpu_cache_get(cachep);
2248         n = get_node(cachep, node);
2249         spin_lock(&n->list_lock);
2250         free_block(cachep, ac->entry, ac->avail, node, &list);
2251         spin_unlock(&n->list_lock);
2252         slabs_destroy(cachep, &list);
2253         ac->avail = 0;
2254 }
2255 
2256 static void drain_cpu_caches(struct kmem_cache *cachep)
2257 {
2258         struct kmem_cache_node *n;
2259         int node;
2260         LIST_HEAD(list);
2261 
2262         on_each_cpu(do_drain, cachep, 1);
2263         check_irq_on();
2264         for_each_kmem_cache_node(cachep, node, n)
2265                 if (n->alien)
2266                         drain_alien_cache(cachep, n->alien);
2267 
2268         for_each_kmem_cache_node(cachep, node, n) {
2269                 spin_lock_irq(&n->list_lock);
2270                 drain_array_locked(cachep, n->shared, node, true, &list);
2271                 spin_unlock_irq(&n->list_lock);
2272 
2273                 slabs_destroy(cachep, &list);
2274         }
2275 }
2276 
2277 /*
2278  * Remove slabs from the list of free slabs.
2279  * Specify the number of slabs to drain in tofree.
2280  *
2281  * Returns the actual number of slabs released.
2282  */
2283 static int drain_freelist(struct kmem_cache *cache,
2284                         struct kmem_cache_node *n, int tofree)
2285 {
2286         struct list_head *p;
2287         int nr_freed;
2288         struct page *page;
2289 
2290         nr_freed = 0;
2291         while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
2292 
2293                 spin_lock_irq(&n->list_lock);
2294                 p = n->slabs_free.prev;
2295                 if (p == &n->slabs_free) {
2296                         spin_unlock_irq(&n->list_lock);
2297                         goto out;
2298                 }
2299 
2300                 page = list_entry(p, struct page, lru);
2301                 list_del(&page->lru);
2302                 n->free_slabs--;
2303                 n->total_slabs--;
2304                 /*
2305                  * Safe to drop the lock. The slab is no longer linked
2306                  * to the cache.
2307                  */
2308                 n->free_objects -= cache->num;
2309                 spin_unlock_irq(&n->list_lock);
2310                 slab_destroy(cache, page);
2311                 nr_freed++;
2312         }
2313 out:
2314         return nr_freed;
2315 }
2316 
2317 int __kmem_cache_shrink(struct kmem_cache *cachep)
2318 {
2319         int ret = 0;
2320         int node;
2321         struct kmem_cache_node *n;
2322 
2323         drain_cpu_caches(cachep);
2324 
2325         check_irq_on();
2326         for_each_kmem_cache_node(cachep, node, n) {
2327                 drain_freelist(cachep, n, INT_MAX);
2328 
2329                 ret += !list_empty(&n->slabs_full) ||
2330                         !list_empty(&n->slabs_partial);
2331         }
2332         return (ret ? 1 : 0);
2333 }
2334 
2335 int __kmem_cache_shutdown(struct kmem_cache *cachep)
2336 {
2337         return __kmem_cache_shrink(cachep);
2338 }
2339 
2340 void __kmem_cache_release(struct kmem_cache *cachep)
2341 {
2342         int i;
2343         struct kmem_cache_node *n;
2344 
2345         cache_random_seq_destroy(cachep);
2346 
2347         free_percpu(cachep->cpu_cache);
2348 
2349         /* NUMA: free the node structures */
2350         for_each_kmem_cache_node(cachep, i, n) {
2351                 kfree(n->shared);
2352                 free_alien_cache(n->alien);
2353                 kfree(n);
2354                 cachep->node[i] = NULL;
2355         }
2356 }
2357 
2358 /*
2359  * Get the memory for a slab management obj.
2360  *
2361  * For a slab cache when the slab descriptor is off-slab, the
2362  * slab descriptor can't come from the same cache which is being created,
2363  * Because if it is the case, that means we defer the creation of
2364  * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point.
2365  * And we eventually call down to __kmem_cache_create(), which
2366  * in turn looks up in the kmalloc_{dma,}_caches for the disired-size one.
2367  * This is a "chicken-and-egg" problem.
2368  *
2369  * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches,
2370  * which are all initialized during kmem_cache_init().
2371  */
2372 static void *alloc_slabmgmt(struct kmem_cache *cachep,
2373                                    struct page *page, int colour_off,
2374                                    gfp_t local_flags, int nodeid)
2375 {
2376         void *freelist;
2377         void *addr = page_address(page);
2378 
2379         page->s_mem = addr + colour_off;
2380         page->active = 0;
2381 
2382         if (OBJFREELIST_SLAB(cachep))
2383                 freelist = NULL;
2384         else if (OFF_SLAB(cachep)) {
2385                 /* Slab management obj is off-slab. */
2386                 freelist = kmem_cache_alloc_node(cachep->freelist_cache,
2387                                               local_flags, nodeid);
2388                 if (!freelist)
2389                         return NULL;
2390         } else {
2391                 /* We will use last bytes at the slab for freelist */
2392                 freelist = addr + (PAGE_SIZE << cachep->gfporder) -
2393                                 cachep->freelist_size;
2394         }
2395 
2396         return freelist;
2397 }
2398 
2399 static inline freelist_idx_t get_free_obj(struct page *page, unsigned int idx)
2400 {
2401         return ((freelist_idx_t *)page->freelist)[idx];
2402 }
2403 
2404 static inline void set_free_obj(struct page *page,
2405                                         unsigned int idx, freelist_idx_t val)
2406 {
2407         ((freelist_idx_t *)(page->freelist))[idx] = val;
2408 }
2409 
2410 static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page)
2411 {
2412 #if DEBUG
2413         int i;
2414 
2415         for (i = 0; i < cachep->num; i++) {
2416                 void *objp = index_to_obj(cachep, page, i);
2417 
2418                 if (cachep->flags & SLAB_STORE_USER)
2419                         *dbg_userword(cachep, objp) = NULL;
2420 
2421                 if (cachep->flags & SLAB_RED_ZONE) {
2422                         *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2423                         *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2424                 }
2425                 /*
2426                  * Constructors are not allowed to allocate memory from the same
2427                  * cache which they are a constructor for.  Otherwise, deadlock.
2428                  * They must also be threaded.
2429                  */
2430                 if (cachep->ctor && !(cachep->flags & SLAB_POISON)) {
2431                         kasan_unpoison_object_data(cachep,
2432                                                    objp + obj_offset(cachep));
2433                         cachep->ctor(objp + obj_offset(cachep));
2434                         kasan_poison_object_data(
2435                                 cachep, objp + obj_offset(cachep));
2436                 }
2437 
2438                 if (cachep->flags & SLAB_RED_ZONE) {
2439                         if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2440                                 slab_error(cachep, "constructor overwrote the end of an object");
2441                         if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2442                                 slab_error(cachep, "constructor overwrote the start of an object");
2443                 }
2444                 /* need to poison the objs? */
2445                 if (cachep->flags & SLAB_POISON) {
2446                         poison_obj(cachep, objp, POISON_FREE);
2447                         slab_kernel_map(cachep, objp, 0, 0);
2448                 }
2449         }
2450 #endif
2451 }
2452 
2453 #ifdef CONFIG_SLAB_FREELIST_RANDOM
2454 /* Hold information during a freelist initialization */
2455 union freelist_init_state {
2456         struct {
2457                 unsigned int pos;
2458                 unsigned int *list;
2459                 unsigned int count;
2460         };
2461         struct rnd_state rnd_state;
2462 };
2463 
2464 /*
2465  * Initialize the state based on the randomization methode available.
2466  * return true if the pre-computed list is available, false otherwize.
2467  */
2468 static bool freelist_state_initialize(union freelist_init_state *state,
2469                                 struct kmem_cache *cachep,
2470                                 unsigned int count)
2471 {
2472         bool ret;
2473         unsigned int rand;
2474 
2475         /* Use best entropy available to define a random shift */
2476         rand = get_random_int();
2477 
2478         /* Use a random state if the pre-computed list is not available */
2479         if (!cachep->random_seq) {
2480                 prandom_seed_state(&state->rnd_state, rand);
2481                 ret = false;
2482         } else {
2483                 state->list = cachep->random_seq;
2484                 state->count = count;
2485                 state->pos = rand % count;
2486                 ret = true;
2487         }
2488         return ret;
2489 }
2490 
2491 /* Get the next entry on the list and randomize it using a random shift */
2492 static freelist_idx_t next_random_slot(union freelist_init_state *state)
2493 {
2494         if (state->pos >= state->count)
2495                 state->pos = 0;
2496         return state->list[state->pos++];
2497 }
2498 
2499 /* Swap two freelist entries */
2500 static void swap_free_obj(struct page *page, unsigned int a, unsigned int b)
2501 {
2502         swap(((freelist_idx_t *)page->freelist)[a],
2503                 ((freelist_idx_t *)page->freelist)[b]);
2504 }
2505 
2506 /*
2507  * Shuffle the freelist initialization state based on pre-computed lists.
2508  * return true if the list was successfully shuffled, false otherwise.
2509  */
2510 static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page)
2511 {
2512         unsigned int objfreelist = 0, i, rand, count = cachep->num;
2513         union freelist_init_state state;
2514         bool precomputed;
2515 
2516         if (count < 2)
2517                 return false;
2518 
2519         precomputed = freelist_state_initialize(&state, cachep, count);
2520 
2521         /* Take a random entry as the objfreelist */
2522         if (OBJFREELIST_SLAB(cachep)) {
2523                 if (!precomputed)
2524                         objfreelist = count - 1;
2525                 else
2526                         objfreelist = next_random_slot(&state);
2527                 page->freelist = index_to_obj(cachep, page, objfreelist) +
2528                                                 obj_offset(cachep);
2529                 count--;
2530         }
2531 
2532         /*
2533          * On early boot, generate the list dynamically.
2534          * Later use a pre-computed list for speed.
2535          */
2536         if (!precomputed) {
2537                 for (i = 0; i < count; i++)
2538                         set_free_obj(page, i, i);
2539 
2540                 /* Fisher-Yates shuffle */
2541                 for (i = count - 1; i > 0; i--) {
2542                         rand = prandom_u32_state(&state.rnd_state);
2543                         rand %= (i + 1);
2544                         swap_free_obj(page, i, rand);
2545                 }
2546         } else {
2547                 for (i = 0; i < count; i++)
2548                         set_free_obj(page, i, next_random_slot(&state));
2549         }
2550 
2551         if (OBJFREELIST_SLAB(cachep))
2552                 set_free_obj(page, cachep->num - 1, objfreelist);
2553 
2554         return true;
2555 }
2556 #else
2557 static inline bool shuffle_freelist(struct kmem_cache *cachep,
2558                                 struct page *page)
2559 {
2560         return false;
2561 }
2562 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
2563 
2564 static void cache_init_objs(struct kmem_cache *cachep,
2565                             struct page *page)
2566 {
2567         int i;
2568         void *objp;
2569         bool shuffled;
2570 
2571         cache_init_objs_debug(cachep, page);
2572 
2573         /* Try to randomize the freelist if enabled */
2574         shuffled = shuffle_freelist(cachep, page);
2575 
2576         if (!shuffled && OBJFREELIST_SLAB(cachep)) {
2577                 page->freelist = index_to_obj(cachep, page, cachep->num - 1) +
2578                                                 obj_offset(cachep);
2579         }
2580 
2581         for (i = 0; i < cachep->num; i++) {
2582                 objp = index_to_obj(cachep, page, i);
2583                 kasan_init_slab_obj(cachep, objp);
2584 
2585                 /* constructor could break poison info */
2586                 if (DEBUG == 0 && cachep->ctor) {
2587                         kasan_unpoison_object_data(cachep, objp);
2588                         cachep->ctor(objp);
2589                         kasan_poison_object_data(cachep, objp);
2590                 }
2591 
2592                 if (!shuffled)
2593                         set_free_obj(page, i, i);
2594         }
2595 }
2596 
2597 static void *slab_get_obj(struct kmem_cache *cachep, struct page *page)
2598 {
2599         void *objp;
2600 
2601         objp = index_to_obj(cachep, page, get_free_obj(page, page->active));
2602         page->active++;
2603 
2604 #if DEBUG
2605         if (cachep->flags & SLAB_STORE_USER)
2606                 set_store_user_dirty(cachep);
2607 #endif
2608 
2609         return objp;
2610 }
2611 
2612 static void slab_put_obj(struct kmem_cache *cachep,
2613                         struct page *page, void *objp)
2614 {
2615         unsigned int objnr = obj_to_index(cachep, page, objp);
2616 #if DEBUG
2617         unsigned int i;
2618 
2619         /* Verify double free bug */
2620         for (i = page->active; i < cachep->num; i++) {
2621                 if (get_free_obj(page, i) == objnr) {
2622                         pr_err("slab: double free detected in cache '%s', objp %p\n",
2623                                cachep->name, objp);
2624                         BUG();
2625                 }
2626         }
2627 #endif
2628         page->active--;
2629         if (!page->freelist)
2630                 page->freelist = objp + obj_offset(cachep);
2631 
2632         set_free_obj(page, page->active, objnr);
2633 }
2634 
2635 /*
2636  * Map pages beginning at addr to the given cache and slab. This is required
2637  * for the slab allocator to be able to lookup the cache and slab of a
2638  * virtual address for kfree, ksize, and slab debugging.
2639  */
2640 static void slab_map_pages(struct kmem_cache *cache, struct page *page,
2641                            void *freelist)
2642 {
2643         page->slab_cache = cache;
2644         page->freelist = freelist;
2645 }
2646 
2647 /*
2648  * Grow (by 1) the number of slabs within a cache.  This is called by
2649  * kmem_cache_alloc() when there are no active objs left in a cache.
2650  */
2651 static struct page *cache_grow_begin(struct kmem_cache *cachep,
2652                                 gfp_t flags, int nodeid)
2653 {
2654         void *freelist;
2655         size_t offset;
2656         gfp_t local_flags;
2657         int page_node;
2658         struct kmem_cache_node *n;
2659         struct page *page;
2660 
2661         /*
2662          * Be lazy and only check for valid flags here,  keeping it out of the
2663          * critical path in kmem_cache_alloc().
2664          */
2665         if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
2666                 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
2667                 flags &= ~GFP_SLAB_BUG_MASK;
2668                 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
2669                                 invalid_mask, &invalid_mask, flags, &flags);
2670                 dump_stack();
2671         }
2672         local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2673 
2674         check_irq_off();
2675         if (gfpflags_allow_blocking(local_flags))
2676                 local_irq_enable();
2677 
2678         /*
2679          * Get mem for the objs.  Attempt to allocate a physical page from
2680          * 'nodeid'.
2681          */
2682         page = kmem_getpages(cachep, local_flags, nodeid);
2683         if (!page)
2684                 goto failed;
2685 
2686         page_node = page_to_nid(page);
2687         n = get_node(cachep, page_node);
2688 
2689         /* Get colour for the slab, and cal the next value. */
2690         n->colour_next++;
2691         if (n->colour_next >= cachep->colour)
2692                 n->colour_next = 0;
2693 
2694         offset = n->colour_next;
2695         if (offset >= cachep->colour)
2696                 offset = 0;
2697 
2698         offset *= cachep->colour_off;
2699 
2700         /* Get slab management. */
2701         freelist = alloc_slabmgmt(cachep, page, offset,
2702                         local_flags & ~GFP_CONSTRAINT_MASK, page_node);
2703         if (OFF_SLAB(cachep) && !freelist)
2704                 goto opps1;
2705 
2706         slab_map_pages(cachep, page, freelist);
2707 
2708         kasan_poison_slab(page);
2709         cache_init_objs(cachep, page);
2710 
2711         if (gfpflags_allow_blocking(local_flags))
2712                 local_irq_disable();
2713 
2714         return page;
2715 
2716 opps1:
2717         kmem_freepages(cachep, page);
2718 failed:
2719         if (gfpflags_allow_blocking(local_flags))
2720                 local_irq_disable();
2721         return NULL;
2722 }
2723 
2724 static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
2725 {
2726         struct kmem_cache_node *n;
2727         void *list = NULL;
2728 
2729         check_irq_off();
2730 
2731         if (!page)
2732                 return;
2733 
2734         INIT_LIST_HEAD(&page->lru);
2735         n = get_node(cachep, page_to_nid(page));
2736 
2737         spin_lock(&n->list_lock);
2738         n->total_slabs++;
2739         if (!page->active) {
2740                 list_add_tail(&page->lru, &(n->slabs_free));
2741                 n->free_slabs++;
2742         } else
2743                 fixup_slab_list(cachep, n, page, &list);
2744 
2745         STATS_INC_GROWN(cachep);
2746         n->free_objects += cachep->num - page->active;
2747         spin_unlock(&n->list_lock);
2748 
2749         fixup_objfreelist_debug(cachep, &list);
2750 }
2751 
2752 #if DEBUG
2753 
2754 /*
2755  * Perform extra freeing checks:
2756  * - detect bad pointers.
2757  * - POISON/RED_ZONE checking
2758  */
2759 static void kfree_debugcheck(const void *objp)
2760 {
2761         if (!virt_addr_valid(objp)) {
2762                 pr_err("kfree_debugcheck: out of range ptr %lxh\n",
2763                        (unsigned long)objp);
2764                 BUG();
2765         }
2766 }
2767 
2768 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2769 {
2770         unsigned long long redzone1, redzone2;
2771 
2772         redzone1 = *dbg_redzone1(cache, obj);
2773         redzone2 = *dbg_redzone2(cache, obj);
2774 
2775         /*
2776          * Redzone is ok.
2777          */
2778         if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2779                 return;
2780 
2781         if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2782                 slab_error(cache, "double free detected");
2783         else
2784                 slab_error(cache, "memory outside object was overwritten");
2785 
2786         pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
2787                obj, redzone1, redzone2);
2788 }
2789 
2790 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2791                                    unsigned long caller)
2792 {
2793         unsigned int objnr;
2794         struct page *page;
2795 
2796         BUG_ON(virt_to_cache(objp) != cachep);
2797 
2798         objp -= obj_offset(cachep);
2799         kfree_debugcheck(objp);
2800         page = virt_to_head_page(objp);
2801 
2802         if (cachep->flags & SLAB_RED_ZONE) {
2803                 verify_redzone_free(cachep, objp);
2804                 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2805                 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2806         }
2807         if (cachep->flags & SLAB_STORE_USER) {
2808                 set_store_user_dirty(cachep);
2809                 *dbg_userword(cachep, objp) = (void *)caller;
2810         }
2811 
2812         objnr = obj_to_index(cachep, page, objp);
2813 
2814         BUG_ON(objnr >= cachep->num);
2815         BUG_ON(objp != index_to_obj(cachep, page, objnr));
2816 
2817         if (cachep->flags & SLAB_POISON) {
2818                 poison_obj(cachep, objp, POISON_FREE);
2819                 slab_kernel_map(cachep, objp, 0, caller);
2820         }
2821         return objp;
2822 }
2823 
2824 #else
2825 #define kfree_debugcheck(x) do { } while(0)
2826 #define cache_free_debugcheck(x,objp,z) (objp)
2827 #endif
2828 
2829 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
2830                                                 void **list)
2831 {
2832 #if DEBUG
2833         void *next = *list;
2834         void *objp;
2835 
2836         while (next) {
2837                 objp = next - obj_offset(cachep);
2838                 next = *(void **)next;
2839                 poison_obj(cachep, objp, POISON_FREE);
2840         }
2841 #endif
2842 }
2843 
2844 static inline void fixup_slab_list(struct kmem_cache *cachep,
2845                                 struct kmem_cache_node *n, struct page *page,
2846                                 void **list)
2847 {
2848         /* move slabp to correct slabp list: */
2849         list_del(&page->lru);
2850         if (page->active == cachep->num) {
2851                 list_add(&page->lru, &n->slabs_full);
2852                 if (OBJFREELIST_SLAB(cachep)) {
2853 #if DEBUG
2854                         /* Poisoning will be done without holding the lock */
2855                         if (cachep->flags & SLAB_POISON) {
2856                                 void **objp = page->freelist;
2857 
2858                                 *objp = *list;
2859                                 *list = objp;
2860                         }
2861 #endif
2862                         page->freelist = NULL;
2863                 }
2864         } else
2865                 list_add(&page->lru, &n->slabs_partial);
2866 }
2867 
2868 /* Try to find non-pfmemalloc slab if needed */
2869 static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n,
2870                                         struct page *page, bool pfmemalloc)
2871 {
2872         if (!page)
2873                 return NULL;
2874 
2875         if (pfmemalloc)
2876                 return page;
2877 
2878         if (!PageSlabPfmemalloc(page))
2879                 return page;
2880 
2881         /* No need to keep pfmemalloc slab if we have enough free objects */
2882         if (n->free_objects > n->free_limit) {
2883                 ClearPageSlabPfmemalloc(page);
2884                 return page;
2885         }
2886 
2887         /* Move pfmemalloc slab to the end of list to speed up next search */
2888         list_del(&page->lru);
2889         if (!page->active) {
2890                 list_add_tail(&page->lru, &n->slabs_free);
2891                 n->free_slabs++;
2892         } else
2893                 list_add_tail(&page->lru, &n->slabs_partial);
2894 
2895         list_for_each_entry(page, &n->slabs_partial, lru) {
2896                 if (!PageSlabPfmemalloc(page))
2897                         return page;
2898         }
2899 
2900         n->free_touched = 1;
2901         list_for_each_entry(page, &n->slabs_free, lru) {
2902                 if (!PageSlabPfmemalloc(page)) {
2903                         n->free_slabs--;
2904                         return page;
2905                 }
2906         }
2907 
2908         return NULL;
2909 }
2910 
2911 static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
2912 {
2913         struct page *page;
2914 
2915         assert_spin_locked(&n->list_lock);
2916         page = list_first_entry_or_null(&n->slabs_partial, struct page, lru);
2917         if (!page) {
2918                 n->free_touched = 1;
2919                 page = list_first_entry_or_null(&n->slabs_free, struct page,
2920                                                 lru);
2921                 if (page)
2922                         n->free_slabs--;
2923         }
2924 
2925         if (sk_memalloc_socks())
2926                 page = get_valid_first_slab(n, page, pfmemalloc);
2927 
2928         return page;
2929 }
2930 
2931 static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
2932                                 struct kmem_cache_node *n, gfp_t flags)
2933 {
2934         struct page *page;
2935         void *obj;
2936         void *list = NULL;
2937 
2938         if (!gfp_pfmemalloc_allowed(flags))
2939                 return NULL;
2940 
2941         spin_lock(&n->list_lock);
2942         page = get_first_slab(n, true);
2943         if (!page) {
2944                 spin_unlock(&n->list_lock);
2945                 return NULL;
2946         }
2947 
2948         obj = slab_get_obj(cachep, page);
2949         n->free_objects--;
2950 
2951         fixup_slab_list(cachep, n, page, &list);
2952 
2953         spin_unlock(&n->list_lock);
2954         fixup_objfreelist_debug(cachep, &list);
2955 
2956         return obj;
2957 }
2958 
2959 /*
2960  * Slab list should be fixed up by fixup_slab_list() for existing slab
2961  * or cache_grow_end() for new slab
2962  */
2963 static __always_inline int alloc_block(struct kmem_cache *cachep,
2964                 struct array_cache *ac, struct page *page, int batchcount)
2965 {
2966         /*
2967          * There must be at least one object available for
2968          * allocation.
2969          */
2970         BUG_ON(page->active >= cachep->num);
2971 
2972         while (page->active < cachep->num && batchcount--) {
2973                 STATS_INC_ALLOCED(cachep);
2974                 STATS_INC_ACTIVE(cachep);
2975                 STATS_SET_HIGH(cachep);
2976 
2977                 ac->entry[ac->avail++] = slab_get_obj(cachep, page);
2978         }
2979 
2980         return batchcount;
2981 }
2982 
2983 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
2984 {
2985         int batchcount;
2986         struct kmem_cache_node *n;
2987         struct array_cache *ac, *shared;
2988         int node;
2989         void *list = NULL;
2990         struct page *page;
2991 
2992         check_irq_off();
2993         node = numa_mem_id();
2994 
2995         ac = cpu_cache_get(cachep);
2996         batchcount = ac->batchcount;
2997         if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2998                 /*
2999                  * If there was little recent activity on this cache, then
3000                  * perform only a partial refill.  Otherwise we could generate
3001                  * refill bouncing.
3002                  */
3003                 batchcount = BATCHREFILL_LIMIT;
3004         }
3005         n = get_node(cachep, node);
3006 
3007         BUG_ON(ac->avail > 0 || !n);
3008         shared = READ_ONCE(n->shared);
3009         if (!n->free_objects && (!shared || !shared->avail))
3010                 goto direct_grow;
3011 
3012         spin_lock(&n->list_lock);
3013         shared = READ_ONCE(n->shared);
3014 
3015         /* See if we can refill from the shared array */
3016         if (shared && transfer_objects(ac, shared, batchcount)) {
3017                 shared->touched = 1;
3018                 goto alloc_done;
3019         }
3020 
3021         while (batchcount > 0) {
3022                 /* Get slab alloc is to come from. */
3023                 page = get_first_slab(n, false);
3024                 if (!page)
3025                         goto must_grow;
3026 
3027                 check_spinlock_acquired(cachep);
3028 
3029                 batchcount = alloc_block(cachep, ac, page, batchcount);
3030                 fixup_slab_list(cachep, n, page, &list);
3031         }
3032 
3033 must_grow:
3034         n->free_objects -= ac->avail;
3035 alloc_done:
3036         spin_unlock(&n->list_lock);
3037         fixup_objfreelist_debug(cachep, &list);
3038 
3039 direct_grow:
3040         if (unlikely(!ac->avail)) {
3041                 /* Check if we can use obj in pfmemalloc slab */
3042                 if (sk_memalloc_socks()) {
3043                         void *obj = cache_alloc_pfmemalloc(cachep, n, flags);
3044 
3045                         if (obj)
3046                                 return obj;
3047                 }
3048 
3049                 page = cache_grow_begin(cachep, gfp_exact_node(flags), node);
3050 
3051                 /*
3052                  * cache_grow_begin() can reenable interrupts,
3053                  * then ac could change.
3054                  */
3055                 ac = cpu_cache_get(cachep);
3056                 if (!ac->avail && page)
3057                         alloc_block(cachep, ac, page, batchcount);
3058                 cache_grow_end(cachep, page);
3059 
3060                 if (!ac->avail)
3061                         return NULL;
3062         }
3063         ac->touched = 1;
3064 
3065         return ac->entry[--ac->avail];
3066 }
3067 
3068 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
3069                                                 gfp_t flags)
3070 {
3071         might_sleep_if(gfpflags_allow_blocking(flags));
3072 }
3073 
3074 #if DEBUG
3075 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
3076                                 gfp_t flags, void *objp, unsigned long caller)
3077 {
3078         if (!objp)
3079                 return objp;
3080         if (cachep->flags & SLAB_POISON) {
3081                 check_poison_obj(cachep, objp);
3082                 slab_kernel_map(cachep, objp, 1, 0);
3083                 poison_obj(cachep, objp, POISON_INUSE);
3084         }
3085         if (cachep->flags & SLAB_STORE_USER)
3086                 *dbg_userword(cachep, objp) = (void *)caller;
3087 
3088         if (cachep->flags & SLAB_RED_ZONE) {
3089                 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
3090                                 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
3091                         slab_error(cachep, "double free, or memory outside object was overwritten");
3092                         pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
3093                                objp, *dbg_redzone1(cachep, objp),
3094                                *dbg_redzone2(cachep, objp));
3095                 }
3096                 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
3097                 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
3098         }
3099 
3100         objp += obj_offset(cachep);
3101         if (cachep->ctor && cachep->flags & SLAB_POISON)
3102                 cachep->ctor(objp);
3103         if (ARCH_SLAB_MINALIGN &&
3104             ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
3105                 pr_err("0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3106                        objp, (int)ARCH_SLAB_MINALIGN);
3107         }
3108         return objp;
3109 }
3110 #else
3111 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3112 #endif
3113 
3114 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3115 {
3116         void *objp;
3117         struct array_cache *ac;
3118 
3119         check_irq_off();
3120 
3121         ac = cpu_cache_get(cachep);
3122         if (likely(ac->avail)) {
3123                 ac->touched = 1;
3124                 objp = ac->entry[--ac->avail];
3125 
3126                 STATS_INC_ALLOCHIT(cachep);
3127                 goto out;
3128         }
3129 
3130         STATS_INC_ALLOCMISS(cachep);
3131         objp = cache_alloc_refill(cachep, flags);
3132         /*
3133          * the 'ac' may be updated by cache_alloc_refill(),
3134          * and kmemleak_erase() requires its correct value.
3135          */
3136         ac = cpu_cache_get(cachep);
3137 
3138 out:
3139         /*
3140          * To avoid a false negative, if an object that is in one of the
3141          * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3142          * treat the array pointers as a reference to the object.
3143          */
3144         if (objp)
3145                 kmemleak_erase(&ac->entry[ac->avail]);
3146         return objp;
3147 }
3148 
3149 #ifdef CONFIG_NUMA
3150 /*
3151  * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set.
3152  *
3153  * If we are in_interrupt, then process context, including cpusets and
3154  * mempolicy, may not apply and should not be used for allocation policy.
3155  */
3156 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3157 {
3158         int nid_alloc, nid_here;
3159 
3160         if (in_interrupt() || (flags & __GFP_THISNODE))
3161                 return NULL;
3162         nid_alloc = nid_here = numa_mem_id();
3163         if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3164                 nid_alloc = cpuset_slab_spread_node();
3165         else if (current->mempolicy)
3166                 nid_alloc = mempolicy_slab_node();
3167         if (nid_alloc != nid_here)
3168                 return ____cache_alloc_node(cachep, flags, nid_alloc);
3169         return NULL;
3170 }
3171 
3172 /*
3173  * Fallback function if there was no memory available and no objects on a
3174  * certain node and fall back is permitted. First we scan all the
3175  * available node for available objects. If that fails then we
3176  * perform an allocation without specifying a node. This allows the page
3177  * allocator to do its reclaim / fallback magic. We then insert the
3178  * slab into the proper nodelist and then allocate from it.
3179  */
3180 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3181 {
3182         struct zonelist *zonelist;
3183         struct zoneref *z;
3184         struct zone *zone;
3185         enum zone_type high_zoneidx = gfp_zone(flags);
3186         void *obj = NULL;
3187         struct page *page;
3188         int nid;
3189         unsigned int cpuset_mems_cookie;
3190 
3191         if (flags & __GFP_THISNODE)
3192                 return NULL;
3193 
3194 retry_cpuset:
3195         cpuset_mems_cookie = read_mems_allowed_begin();
3196         zonelist = node_zonelist(mempolicy_slab_node(), flags);
3197 
3198 retry:
3199         /*
3200          * Look through allowed nodes for objects available
3201          * from existing per node queues.
3202          */
3203         for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
3204                 nid = zone_to_nid(zone);
3205 
3206                 if (cpuset_zone_allowed(zone, flags) &&
3207                         get_node(cache, nid) &&
3208                         get_node(cache, nid)->free_objects) {
3209                                 obj = ____cache_alloc_node(cache,
3210                                         gfp_exact_node(flags), nid);
3211                                 if (obj)
3212                                         break;
3213                 }
3214         }
3215 
3216         if (!obj) {
3217                 /*
3218                  * This allocation will be performed within the constraints
3219                  * of the current cpuset / memory policy requirements.
3220                  * We may trigger various forms of reclaim on the allowed
3221                  * set and go into memory reserves if necessary.
3222                  */
3223                 page = cache_grow_begin(cache, flags, numa_mem_id());
3224                 cache_grow_end(cache, page);
3225                 if (page) {
3226                         nid = page_to_nid(page);
3227                         obj = ____cache_alloc_node(cache,
3228                                 gfp_exact_node(flags), nid);
3229 
3230                         /*
3231                          * Another processor may allocate the objects in
3232                          * the slab since we are not holding any locks.
3233                          */
3234                         if (!obj)
3235                                 goto retry;
3236                 }
3237         }
3238 
3239         if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie)))
3240                 goto retry_cpuset;
3241         return obj;
3242 }
3243 
3244 /*
3245  * A interface to enable slab creation on nodeid
3246  */
3247 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3248                                 int nodeid)
3249 {
3250         struct page *page;
3251         struct kmem_cache_node *n;
3252         void *obj = NULL;
3253         void *list = NULL;
3254 
3255         VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES);
3256         n = get_node(cachep, nodeid);
3257         BUG_ON(!n);
3258 
3259         check_irq_off();
3260         spin_lock(&n->list_lock);
3261         page = get_first_slab(n, false);
3262         if (!page)
3263                 goto must_grow;
3264 
3265         check_spinlock_acquired_node(cachep, nodeid);
3266 
3267         STATS_INC_NODEALLOCS(cachep);
3268         STATS_INC_ACTIVE(cachep);
3269         STATS_SET_HIGH(cachep);
3270 
3271         BUG_ON(page->active == cachep->num);
3272 
3273         obj = slab_get_obj(cachep, page);
3274         n->free_objects--;
3275 
3276         fixup_slab_list(cachep, n, page, &list);
3277 
3278         spin_unlock(&n->list_lock);
3279         fixup_objfreelist_debug(cachep, &list);
3280         return obj;
3281 
3282 must_grow:
3283         spin_unlock(&n->list_lock);
3284         page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid);
3285         if (page) {
3286                 /* This slab isn't counted yet so don't update free_objects */
3287                 obj = slab_get_obj(cachep, page);
3288         }
3289         cache_grow_end(cachep, page);
3290 
3291         return obj ? obj : fallback_alloc(cachep, flags);
3292 }
3293 
3294 static __always_inline void *
3295 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
3296                    unsigned long caller)
3297 {
3298         unsigned long save_flags;
3299         void *ptr;
3300         int slab_node = numa_mem_id();
3301 
3302         flags &= gfp_allowed_mask;
3303         cachep = slab_pre_alloc_hook(cachep, flags);
3304         if (unlikely(!cachep))
3305                 return NULL;
3306 
3307         cache_alloc_debugcheck_before(cachep, flags);
3308         local_irq_save(save_flags);
3309 
3310         if (nodeid == NUMA_NO_NODE)
3311                 nodeid = slab_node;
3312 
3313         if (unlikely(!get_node(cachep, nodeid))) {
3314                 /* Node not bootstrapped yet */
3315                 ptr = fallback_alloc(cachep, flags);
3316                 goto out;
3317         }
3318 
3319         if (nodeid == slab_node) {
3320                 /*
3321                  * Use the locally cached objects if possible.
3322                  * However ____cache_alloc does not allow fallback
3323                  * to other nodes. It may fail while we still have
3324                  * objects on other nodes available.
3325                  */
3326                 ptr = ____cache_alloc(cachep, flags);
3327                 if (ptr)
3328                         goto out;
3329         }
3330         /* ___cache_alloc_node can fall back to other nodes */
3331         ptr = ____cache_alloc_node(cachep, flags, nodeid);
3332   out:
3333         local_irq_restore(save_flags);
3334         ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3335 
3336         if (unlikely(flags & __GFP_ZERO) && ptr)
3337                 memset(ptr, 0, cachep->object_size);
3338 
3339         slab_post_alloc_hook(cachep, flags, 1, &ptr);
3340         return ptr;
3341 }
3342 
3343 static __always_inline void *
3344 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3345 {
3346         void *objp;
3347 
3348         if (current->mempolicy || cpuset_do_slab_mem_spread()) {
3349                 objp = alternate_node_alloc(cache, flags);
3350                 if (objp)
3351                         goto out;
3352         }
3353         objp = ____cache_alloc(cache, flags);
3354 
3355         /*
3356          * We may just have run out of memory on the local node.
3357          * ____cache_alloc_node() knows how to locate memory on other nodes
3358          */
3359         if (!objp)
3360                 objp = ____cache_alloc_node(cache, flags, numa_mem_id());
3361 
3362   out:
3363         return objp;
3364 }
3365 #else
3366 
3367 static __always_inline void *
3368 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3369 {
3370         return ____cache_alloc(cachep, flags);
3371 }
3372 
3373 #endif /* CONFIG_NUMA */
3374 
3375 static __always_inline void *
3376 slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
3377 {
3378         unsigned long save_flags;
3379         void *objp;
3380 
3381         flags &= gfp_allowed_mask;
3382         cachep = slab_pre_alloc_hook(cachep, flags);
3383         if (unlikely(!cachep))
3384                 return NULL;
3385 
3386         cache_alloc_debugcheck_before(cachep, flags);
3387         local_irq_save(save_flags);
3388         objp = __do_cache_alloc(cachep, flags);
3389         local_irq_restore(save_flags);
3390         objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3391         prefetchw(objp);
3392 
3393         if (unlikely(flags & __GFP_ZERO) && objp)
3394                 memset(objp, 0, cachep->object_size);
3395 
3396         slab_post_alloc_hook(cachep, flags, 1, &objp);
3397         return objp;
3398 }
3399 
3400 /*
3401  * Caller needs to acquire correct kmem_cache_node's list_lock
3402  * @list: List of detached free slabs should be freed by caller
3403  */
3404 static void free_block(struct kmem_cache *cachep, void **objpp,
3405                         int nr_objects, int node, struct list_head *list)
3406 {
3407         int i;
3408         struct kmem_cache_node *n = get_node(cachep, node);
3409         struct page *page;
3410 
3411         n->free_objects += nr_objects;
3412 
3413         for (i = 0; i < nr_objects; i++) {
3414                 void *objp;
3415                 struct page *page;
3416 
3417                 objp = objpp[i];
3418 
3419                 page = virt_to_head_page(objp);
3420                 list_del(&page->lru);
3421                 check_spinlock_acquired_node(cachep, node);
3422                 slab_put_obj(cachep, page, objp);
3423                 STATS_DEC_ACTIVE(cachep);
3424 
3425                 /* fixup slab chains */
3426                 if (page->active == 0) {
3427                         list_add(&page->lru, &n->slabs_free);
3428                         n->free_slabs++;
3429                 } else {
3430                         /* Unconditionally move a slab to the end of the
3431                          * partial list on free - maximum time for the
3432                          * other objects to be freed, too.
3433                          */
3434                         list_add_tail(&page->lru, &n->slabs_partial);
3435                 }
3436         }
3437 
3438         while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) {
3439                 n->free_objects -= cachep->num;
3440 
3441                 page = list_last_entry(&n->slabs_free, struct page, lru);
3442                 list_move(&page->lru, list);
3443                 n->free_slabs--;
3444                 n->total_slabs--;
3445         }
3446 }
3447 
3448 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3449 {
3450         int batchcount;
3451         struct kmem_cache_node *n;
3452         int node = numa_mem_id();
3453         LIST_HEAD(list);
3454 
3455         batchcount = ac->batchcount;
3456 
3457         check_irq_off();
3458         n = get_node(cachep, node);
3459         spin_lock(&n->list_lock);
3460         if (n->shared) {
3461                 struct array_cache *shared_array = n->shared;
3462                 int max = shared_array->limit - shared_array->avail;
3463                 if (max) {
3464                         if (batchcount > max)
3465                                 batchcount = max;
3466                         memcpy(&(shared_array->entry[shared_array->avail]),
3467                                ac->entry, sizeof(void *) * batchcount);
3468                         shared_array->avail += batchcount;
3469                         goto free_done;
3470                 }
3471         }
3472 
3473         free_block(cachep, ac->entry, batchcount, node, &list);
3474 free_done:
3475 #if STATS
3476         {
3477                 int i = 0;
3478                 struct page *page;
3479 
3480                 list_for_each_entry(page, &n->slabs_free, lru) {
3481                         BUG_ON(page->active);
3482 
3483                         i++;
3484                 }
3485                 STATS_SET_FREEABLE(cachep, i);
3486         }
3487 #endif
3488         spin_unlock(&n->list_lock);
3489         slabs_destroy(cachep, &list);
3490         ac->avail -= batchcount;
3491         memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3492 }
3493 
3494 /*
3495  * Release an obj back to its cache. If the obj has a constructed state, it must
3496  * be in this state _before_ it is released.  Called with disabled ints.
3497  */
3498 static inline void __cache_free(struct kmem_cache *cachep, void *objp,
3499                                 unsigned long caller)
3500 {
3501         /* Put the object into the quarantine, don't touch it for now. */
3502         if (kasan_slab_free(cachep, objp))
3503                 return;
3504 
3505         ___cache_free(cachep, objp, caller);
3506 }
3507 
3508 void ___cache_free(struct kmem_cache *cachep, void *objp,
3509                 unsigned long caller)
3510 {
3511         struct array_cache *ac = cpu_cache_get(cachep);
3512 
3513         check_irq_off();
3514         kmemleak_free_recursive(objp, cachep->flags);
3515         objp = cache_free_debugcheck(cachep, objp, caller);
3516 
3517         kmemcheck_slab_free(cachep, objp, cachep->object_size);
3518 
3519         /*
3520          * Skip calling cache_free_alien() when the platform is not numa.
3521          * This will avoid cache misses that happen while accessing slabp (which
3522          * is per page memory  reference) to get nodeid. Instead use a global
3523          * variable to skip the call, which is mostly likely to be present in
3524          * the cache.
3525          */
3526         if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3527                 return;
3528 
3529         if (ac->avail < ac->limit) {
3530                 STATS_INC_FREEHIT(cachep);
3531         } else {
3532                 STATS_INC_FREEMISS(cachep);
3533                 cache_flusharray(cachep, ac);
3534         }
3535 
3536         if (sk_memalloc_socks()) {
3537                 struct page *page = virt_to_head_page(objp);
3538 
3539                 if (unlikely(PageSlabPfmemalloc(page))) {
3540                         cache_free_pfmemalloc(cachep, page, objp);
3541                         return;
3542                 }
3543         }
3544 
3545         ac->entry[ac->avail++] = objp;
3546 }
3547 
3548 /**
3549  * kmem_cache_alloc - Allocate an object
3550  * @cachep: The cache to allocate from.
3551  * @flags: See kmalloc().
3552  *
3553  * Allocate an object from this cache.  The flags are only relevant
3554  * if the cache has no available objects.
3555  */
3556 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3557 {
3558         void *ret = slab_alloc(cachep, flags, _RET_IP_);
3559 
3560         kasan_slab_alloc(cachep, ret, flags);
3561         trace_kmem_cache_alloc(_RET_IP_, ret,
3562                                cachep->object_size, cachep->size, flags);
3563 
3564         return ret;
3565 }
3566 EXPORT_SYMBOL(kmem_cache_alloc);
3567 
3568 static __always_inline void
3569 cache_alloc_debugcheck_after_bulk(struct kmem_cache *s, gfp_t flags,
3570                                   size_t size, void **p, unsigned long caller)
3571 {
3572         size_t i;
3573 
3574         for (i = 0; i < size; i++)
3575                 p[i] = cache_alloc_debugcheck_after(s, flags, p[i], caller);
3576 }
3577 
3578 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3579                           void **p)
3580 {
3581         size_t i;
3582 
3583         s = slab_pre_alloc_hook(s, flags);
3584         if (!s)
3585                 return 0;
3586 
3587         cache_alloc_debugcheck_before(s, flags);
3588 
3589         local_irq_disable();
3590         for (i = 0; i < size; i++) {
3591                 void *objp = __do_cache_alloc(s, flags);
3592 
3593                 if (unlikely(!objp))
3594                         goto error;
3595                 p[i] = objp;
3596         }
3597         local_irq_enable();
3598 
3599         cache_alloc_debugcheck_after_bulk(s, flags, size, p, _RET_IP_);
3600 
3601         /* Clear memory outside IRQ disabled section */
3602         if (unlikely(flags & __GFP_ZERO))
3603                 for (i = 0; i < size; i++)
3604                         memset(p[i], 0, s->object_size);
3605 
3606         slab_post_alloc_hook(s, flags, size, p);
3607         /* FIXME: Trace call missing. Christoph would like a bulk variant */
3608         return size;
3609 error:
3610         local_irq_enable();
3611         cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_);
3612         slab_post_alloc_hook(s, flags, i, p);
3613         __kmem_cache_free_bulk(s, i, p);
3614         return 0;
3615 }
3616 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3617 
3618 #ifdef CONFIG_TRACING
3619 void *
3620 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
3621 {
3622         void *ret;
3623 
3624         ret = slab_alloc(cachep, flags, _RET_IP_);
3625 
3626         kasan_kmalloc(cachep, ret, size, flags);
3627         trace_kmalloc(_RET_IP_, ret,
3628                       size, cachep->size, flags);
3629         return ret;
3630 }
3631 EXPORT_SYMBOL(kmem_cache_alloc_trace);
3632 #endif
3633 
3634 #ifdef CONFIG_NUMA
3635 /**
3636  * kmem_cache_alloc_node - Allocate an object on the specified node
3637  * @cachep: The cache to allocate from.
3638  * @flags: See kmalloc().
3639  * @nodeid: node number of the target node.
3640  *
3641  * Identical to kmem_cache_alloc but it will allocate memory on the given
3642  * node, which can improve the performance for cpu bound structures.
3643  *
3644  * Fallback to other node is possible if __GFP_THISNODE is not set.
3645  */
3646 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3647 {
3648         void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3649 
3650         kasan_slab_alloc(cachep, ret, flags);
3651         trace_kmem_cache_alloc_node(_RET_IP_, ret,
3652                                     cachep->object_size, cachep->size,
3653                                     flags, nodeid);
3654 
3655         return ret;
3656 }
3657 EXPORT_SYMBOL(kmem_cache_alloc_node);
3658 
3659 #ifdef CONFIG_TRACING
3660 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
3661                                   gfp_t flags,
3662                                   int nodeid,
3663                                   size_t size)
3664 {
3665         void *ret;
3666 
3667         ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
3668 
3669         kasan_kmalloc(cachep, ret, size, flags);
3670         trace_kmalloc_node(_RET_IP_, ret,
3671                            size, cachep->size,
3672                            flags, nodeid);
3673         return ret;
3674 }
3675 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3676 #endif
3677 
3678 static __always_inline void *
3679 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
3680 {
3681         struct kmem_cache *cachep;
3682         void *ret;
3683 
3684         cachep = kmalloc_slab(size, flags);
3685         if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3686                 return cachep;
3687         ret = kmem_cache_alloc_node_trace(cachep, flags, node, size);
3688         kasan_kmalloc(cachep, ret, size, flags);
3689 
3690         return ret;
3691 }
3692 
3693 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3694 {
3695         return __do_kmalloc_node(size, flags, node, _RET_IP_);
3696 }
3697 EXPORT_SYMBOL(__kmalloc_node);
3698 
3699 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3700                 int node, unsigned long caller)
3701 {
3702         return __do_kmalloc_node(size, flags, node, caller);
3703 }
3704 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3705 #endif /* CONFIG_NUMA */
3706 
3707 /**
3708  * __do_kmalloc - allocate memory
3709  * @size: how many bytes of memory are required.
3710  * @flags: the type of memory to allocate (see kmalloc).
3711  * @caller: function caller for debug tracking of the caller
3712  */
3713 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3714                                           unsigned long caller)
3715 {
3716         struct kmem_cache *cachep;
3717         void *ret;
3718 
3719         cachep = kmalloc_slab(size, flags);
3720         if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3721                 return cachep;
3722         ret = slab_alloc(cachep, flags, caller);
3723 
3724         kasan_kmalloc(cachep, ret, size, flags);
3725         trace_kmalloc(caller, ret,
3726                       size, cachep->size, flags);
3727 
3728         return ret;
3729 }
3730 
3731 void *__kmalloc(size_t size, gfp_t flags)
3732 {
3733         return __do_kmalloc(size, flags, _RET_IP_);
3734 }
3735 EXPORT_SYMBOL(__kmalloc);
3736 
3737 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3738 {
3739         return __do_kmalloc(size, flags, caller);
3740 }
3741 EXPORT_SYMBOL(__kmalloc_track_caller);
3742 
3743 /**
3744  * kmem_cache_free - Deallocate an object
3745  * @cachep: The cache the allocation was from.
3746  * @objp: The previously allocated object.
3747  *
3748  * Free an object which was previously allocated from this
3749  * cache.
3750  */
3751 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3752 {
3753         unsigned long flags;
3754         cachep = cache_from_obj(cachep, objp);
3755         if (!cachep)
3756                 return;
3757 
3758         local_irq_save(flags);
3759         debug_check_no_locks_freed(objp, cachep->object_size);
3760         if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3761                 debug_check_no_obj_freed(objp, cachep->object_size);
3762         __cache_free(cachep, objp, _RET_IP_);
3763         local_irq_restore(flags);
3764 
3765         trace_kmem_cache_free(_RET_IP_, objp);
3766 }
3767 EXPORT_SYMBOL(kmem_cache_free);
3768 
3769 void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p)
3770 {
3771         struct kmem_cache *s;
3772         size_t i;
3773 
3774         local_irq_disable();
3775         for (i = 0; i < size; i++) {
3776                 void *objp = p[i];
3777 
3778                 if (!orig_s) /* called via kfree_bulk */
3779                         s = virt_to_cache(objp);
3780                 else
3781                         s = cache_from_obj(orig_s, objp);
3782 
3783                 debug_check_no_locks_freed(objp, s->object_size);
3784                 if (!(s->flags & SLAB_DEBUG_OBJECTS))
3785                         debug_check_no_obj_freed(objp, s->object_size);
3786 
3787                 __cache_free(s, objp, _RET_IP_);
3788         }
3789         local_irq_enable();
3790 
3791         /* FIXME: add tracing */
3792 }
3793 EXPORT_SYMBOL(kmem_cache_free_bulk);
3794 
3795 /**
3796  * kfree - free previously allocated memory
3797  * @objp: pointer returned by kmalloc.
3798  *
3799  * If @objp is NULL, no operation is performed.
3800  *
3801  * Don't free memory not originally allocated by kmalloc()
3802  * or you will run into trouble.
3803  */
3804 void kfree(const void *objp)
3805 {
3806         struct kmem_cache *c;
3807         unsigned long flags;
3808 
3809         trace_kfree(_RET_IP_, objp);
3810 
3811         if (unlikely(ZERO_OR_NULL_PTR(objp)))
3812                 return;
3813         local_irq_save(flags);
3814         kfree_debugcheck(objp);
3815         c = virt_to_cache(objp);
3816         debug_check_no_locks_freed(objp, c->object_size);
3817 
3818         debug_check_no_obj_freed(objp, c->object_size);
3819         __cache_free(c, (void *)objp, _RET_IP_);
3820         local_irq_restore(flags);
3821 }
3822 EXPORT_SYMBOL(kfree);
3823 
3824 /*
3825  * This initializes kmem_cache_node or resizes various caches for all nodes.
3826  */
3827 static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp)
3828 {
3829         int ret;
3830         int node;
3831         struct kmem_cache_node *n;
3832 
3833         for_each_online_node(node) {
3834                 ret = setup_kmem_cache_node(cachep, node, gfp, true);
3835                 if (ret)
3836                         goto fail;
3837 
3838         }
3839 
3840         return 0;
3841 
3842 fail:
3843         if (!cachep->list.next) {
3844                 /* Cache is not active yet. Roll back what we did */
3845                 node--;
3846                 while (node >= 0) {
3847                         n = get_node(cachep, node);
3848                         if (n) {
3849                                 kfree(n->shared);
3850                                 free_alien_cache(n->alien);
3851                                 kfree(n);
3852                                 cachep->node[node] = NULL;
3853                         }
3854                         node--;
3855                 }
3856         }
3857         return -ENOMEM;
3858 }
3859 
3860 /* Always called with the slab_mutex held */
3861 static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
3862                                 int batchcount, int shared, gfp_t gfp)
3863 {
3864         struct array_cache __percpu *cpu_cache, *prev;
3865         int cpu;
3866 
3867         cpu_cache = alloc_kmem_cache_cpus(cachep, limit, batchcount);
3868         if (!cpu_cache)
3869                 return -ENOMEM;
3870 
3871         prev = cachep->cpu_cache;
3872         cachep->cpu_cache = cpu_cache;
3873         kick_all_cpus_sync();
3874 
3875         check_irq_on();
3876         cachep->batchcount = batchcount;
3877         cachep->limit = limit;
3878         cachep->shared = shared;
3879 
3880         if (!prev)
3881                 goto setup_node;
3882 
3883         for_each_online_cpu(cpu) {
3884                 LIST_HEAD(list);
3885                 int node;
3886                 struct kmem_cache_node *n;
3887                 struct array_cache *ac = per_cpu_ptr(prev, cpu);
3888 
3889                 node = cpu_to_mem(cpu);
3890                 n = get_node(cachep, node);
3891                 spin_lock_irq(&n->list_lock);
3892                 free_block(cachep, ac->entry, ac->avail, node, &list);
3893                 spin_unlock_irq(&n->list_lock);
3894                 slabs_destroy(cachep, &list);
3895         }
3896         free_percpu(prev);
3897 
3898 setup_node:
3899         return setup_kmem_cache_nodes(cachep, gfp);
3900 }
3901 
3902 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3903                                 int batchcount, int shared, gfp_t gfp)
3904 {
3905         int ret;
3906         struct kmem_cache *c;
3907 
3908         ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3909 
3910         if (slab_state < FULL)
3911                 return ret;
3912 
3913         if ((ret < 0) || !is_root_cache(cachep))
3914                 return ret;
3915 
3916         lockdep_assert_held(&slab_mutex);
3917         for_each_memcg_cache(c, cachep) {
3918                 /* return value determined by the root cache only */
3919                 __do_tune_cpucache(c, limit, batchcount, shared, gfp);
3920         }
3921 
3922         return ret;
3923 }
3924 
3925 /* Called with slab_mutex held always */
3926 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3927 {
3928         int err;
3929         int limit = 0;
3930         int shared = 0;
3931         int batchcount = 0;
3932 
3933         err = cache_random_seq_create(cachep, cachep->num, gfp);
3934         if (err)
3935                 goto end;
3936 
3937         if (!is_root_cache(cachep)) {
3938                 struct kmem_cache *root = memcg_root_cache(cachep);
3939                 limit = root->limit;
3940                 shared = root->shared;
3941                 batchcount = root->batchcount;
3942         }
3943 
3944         if (limit && shared && batchcount)
3945                 goto skip_setup;
3946         /*
3947          * The head array serves three purposes:
3948          * - create a LIFO ordering, i.e. return objects that are cache-warm
3949          * - reduce the number of spinlock operations.
3950          * - reduce the number of linked list operations on the slab and
3951          *   bufctl chains: array operations are cheaper.
3952          * The numbers are guessed, we should auto-tune as described by
3953          * Bonwick.
3954          */
3955         if (cachep->size > 131072)
3956                 limit = 1;
3957         else if (cachep->size > PAGE_SIZE)
3958                 limit = 8;
3959         else if (cachep->size > 1024)
3960                 limit = 24;
3961         else if (cachep->size > 256)
3962                 limit = 54;
3963         else
3964                 limit = 120;
3965 
3966         /*
3967          * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3968          * allocation behaviour: Most allocs on one cpu, most free operations
3969          * on another cpu. For these cases, an efficient object passing between
3970          * cpus is necessary. This is provided by a shared array. The array
3971          * replaces Bonwick's magazine layer.
3972          * On uniprocessor, it's functionally equivalent (but less efficient)
3973          * to a larger limit. Thus disabled by default.
3974          */
3975         shared = 0;
3976         if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
3977                 shared = 8;
3978 
3979 #if DEBUG
3980         /*
3981          * With debugging enabled, large batchcount lead to excessively long
3982          * periods with disabled local interrupts. Limit the batchcount
3983          */
3984         if (limit > 32)
3985                 limit = 32;
3986 #endif
3987         batchcount = (limit + 1) / 2;
3988 skip_setup:
3989         err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3990 end:
3991         if (err)
3992                 pr_err("enable_cpucache failed for %s, error %d\n",
3993                        cachep->name, -err);
3994         return err;
3995 }
3996 
3997 /*
3998  * Drain an array if it contains any elements taking the node lock only if
3999  * necessary. Note that the node listlock also protects the array_cache
4000  * if drain_array() is used on the shared array.
4001  */
4002 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
4003                          struct array_cache *ac, int node)
4004 {
4005         LIST_HEAD(list);
4006 
4007         /* ac from n->shared can be freed if we don't hold the slab_mutex. */
4008         check_mutex_acquired();
4009 
4010         if (!ac || !ac->avail)
4011                 return;
4012 
4013         if (ac->touched) {
4014                 ac->touched = 0;
4015                 return;
4016         }
4017 
4018         spin_lock_irq(&n->list_lock);
4019         drain_array_locked(cachep, ac, node, false, &list);
4020         spin_unlock_irq(&n->list_lock);
4021 
4022         slabs_destroy(cachep, &list);
4023 }
4024 
4025 /**
4026  * cache_reap - Reclaim memory from caches.
4027  * @w: work descriptor
4028  *
4029  * Called from workqueue/eventd every few seconds.
4030  * Purpose:
4031  * - clear the per-cpu caches for this CPU.
4032  * - return freeable pages to the main free memory pool.
4033  *
4034  * If we cannot acquire the cache chain mutex then just give up - we'll try
4035  * again on the next iteration.
4036  */
4037 static void cache_reap(struct work_struct *w)
4038 {
4039         struct kmem_cache *searchp;
4040         struct kmem_cache_node *n;
4041         int node = numa_mem_id();
4042         struct delayed_work *work = to_delayed_work(w);
4043 
4044         if (!mutex_trylock(&slab_mutex))
4045                 /* Give up. Setup the next iteration. */
4046                 goto out;
4047 
4048         list_for_each_entry(searchp, &slab_caches, list) {
4049                 check_irq_on();
4050 
4051                 /*
4052                  * We only take the node lock if absolutely necessary and we
4053                  * have established with reasonable certainty that
4054                  * we can do some work if the lock was obtained.
4055                  */
4056                 n = get_node(searchp, node);
4057 
4058                 reap_alien(searchp, n);
4059 
4060                 drain_array(searchp, n, cpu_cache_get(searchp), node);
4061 
4062                 /*
4063                  * These are racy checks but it does not matter
4064                  * if we skip one check or scan twice.
4065                  */
4066                 if (time_after(n->next_reap, jiffies))
4067                         goto next;
4068 
4069                 n->next_reap = jiffies + REAPTIMEOUT_NODE;
4070 
4071                 drain_array(searchp, n, n->shared, node);
4072 
4073                 if (n->free_touched)
4074                         n->free_touched = 0;
4075                 else {
4076                         int freed;
4077 
4078                         freed = drain_freelist(searchp, n, (n->free_limit +
4079                                 5 * searchp->num - 1) / (5 * searchp->num));
4080                         STATS_ADD_REAPED(searchp, freed);
4081                 }
4082 next:
4083                 cond_resched();
4084         }
4085         check_irq_on();
4086         mutex_unlock(&slab_mutex);
4087         next_reap_node();
4088 out:
4089         /* Set up the next iteration */
4090         schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC));
4091 }
4092 
4093 #ifdef CONFIG_SLABINFO
4094 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
4095 {
4096         unsigned long active_objs, num_objs, active_slabs;
4097         unsigned long total_slabs = 0, free_objs = 0, shared_avail = 0;
4098         unsigned long free_slabs = 0;
4099         int node;
4100         struct kmem_cache_node *n;
4101 
4102         for_each_kmem_cache_node(cachep, node, n) {
4103                 check_irq_on();
4104                 spin_lock_irq(&n->list_lock);
4105 
4106                 total_slabs += n->total_slabs;
4107                 free_slabs += n->free_slabs;
4108                 free_objs += n->free_objects;
4109 
4110                 if (n->shared)
4111                         shared_avail += n->shared->avail;
4112 
4113                 spin_unlock_irq(&n->list_lock);
4114         }
4115         num_objs = total_slabs * cachep->num;
4116         active_slabs = total_slabs - free_slabs;
4117         active_objs = num_objs - free_objs;
4118 
4119         sinfo->active_objs = active_objs;
4120         sinfo->num_objs = num_objs;
4121         sinfo->active_slabs = active_slabs;
4122         sinfo->num_slabs = total_slabs;
4123         sinfo->shared_avail = shared_avail;
4124         sinfo->limit = cachep->limit;
4125         sinfo->batchcount = cachep->batchcount;
4126         sinfo->shared = cachep->shared;
4127         sinfo->objects_per_slab = cachep->num;
4128         sinfo->cache_order = cachep->gfporder;
4129 }
4130 
4131 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
4132 {
4133 #if STATS
4134         {                       /* node stats */
4135                 unsigned long high = cachep->high_mark;
4136                 unsigned long allocs = cachep->num_allocations;
4137                 unsigned long grown = cachep->grown;
4138                 unsigned long reaped = cachep->reaped;
4139                 unsigned long errors = cachep->errors;
4140                 unsigned long max_freeable = cachep->max_freeable;
4141                 unsigned long node_allocs = cachep->node_allocs;
4142                 unsigned long node_frees = cachep->node_frees;
4143                 unsigned long overflows = cachep->node_overflow;
4144 
4145                 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu",
4146                            allocs, high, grown,
4147                            reaped, errors, max_freeable, node_allocs,
4148                            node_frees, overflows);
4149         }
4150         /* cpu stats */
4151         {
4152                 unsigned long allochit = atomic_read(&cachep->allochit);
4153                 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4154                 unsigned long freehit = atomic_read(&cachep->freehit);
4155                 unsigned long freemiss = atomic_read(&cachep->freemiss);
4156 
4157                 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4158                            allochit, allocmiss, freehit, freemiss);
4159         }
4160 #endif
4161 }
4162 
4163 #define MAX_SLABINFO_WRITE 128
4164 /**
4165  * slabinfo_write - Tuning for the slab allocator
4166  * @file: unused
4167  * @buffer: user buffer
4168  * @count: data length
4169  * @ppos: unused
4170  */
4171 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
4172                        size_t count, loff_t *ppos)
4173 {
4174         char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4175         int limit, batchcount, shared, res;
4176         struct kmem_cache *cachep;
4177 
4178         if (count > MAX_SLABINFO_WRITE)
4179                 return -EINVAL;
4180         if (copy_from_user(&kbuf, buffer, count))
4181                 return -EFAULT;
4182         kbuf[MAX_SLABINFO_WRITE] = '\0';
4183 
4184         tmp = strchr(kbuf, ' ');
4185         if (!tmp)
4186                 return -EINVAL;
4187         *tmp = '\0';
4188         tmp++;
4189         if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4190                 return -EINVAL;
4191 
4192         /* Find the cache in the chain of caches. */
4193         mutex_lock(&slab_mutex);
4194         res = -EINVAL;
4195         list_for_each_entry(cachep, &slab_caches, list) {
4196                 if (!strcmp(cachep->name, kbuf)) {
4197                         if (limit < 1 || batchcount < 1 ||
4198                                         batchcount > limit || shared < 0) {
4199                                 res = 0;
4200                         } else {
4201                                 res = do_tune_cpucache(cachep, limit,
4202                                                        batchcount, shared,
4203                                                        GFP_KERNEL);
4204                         }
4205                         break;
4206                 }
4207         }
4208         mutex_unlock(&slab_mutex);
4209         if (res >= 0)
4210                 res = count;
4211         return res;
4212 }
4213 
4214 #ifdef CONFIG_DEBUG_SLAB_LEAK
4215 
4216 static inline int add_caller(unsigned long *n, unsigned long v)
4217 {
4218         unsigned long *p;
4219         int l;
4220         if (!v)
4221                 return 1;
4222         l = n[1];
4223         p = n + 2;
4224         while (l) {
4225                 int i = l/2;
4226                 unsigned long *q = p + 2 * i;
4227                 if (*q == v) {
4228                         q[1]++;
4229                         return 1;
4230                 }
4231                 if (*q > v) {
4232                         l = i;
4233                 } else {
4234                         p = q + 2;
4235                         l -= i + 1;
4236                 }
4237         }
4238         if (++n[1] == n[0])
4239                 return 0;
4240         memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
4241         p[0] = v;
4242         p[1] = 1;
4243         return 1;
4244 }
4245 
4246 static void handle_slab(unsigned long *n, struct kmem_cache *c,
4247                                                 struct page *page)
4248 {
4249         void *p;
4250         int i, j;
4251         unsigned long v;
4252 
4253         if (n[0] == n[1])
4254                 return;
4255         for (i = 0, p = page->s_mem; i < c->num; i++, p += c->size) {
4256                 bool active = true;
4257 
4258                 for (j = page->active; j < c->num; j++) {
4259                         if (get_free_obj(page, j) == i) {
4260                                 active = false;
4261                                 break;
4262                         }
4263                 }
4264 
4265                 if (!active)
4266                         continue;
4267 
4268                 /*
4269                  * probe_kernel_read() is used for DEBUG_PAGEALLOC. page table
4270                  * mapping is established when actual object allocation and
4271                  * we could mistakenly access the unmapped object in the cpu
4272                  * cache.
4273                  */
4274                 if (probe_kernel_read(&v, dbg_userword(c, p), sizeof(v)))
4275                         continue;
4276 
4277                 if (!add_caller(n, v))
4278                         return;
4279         }
4280 }
4281 
4282 static void show_symbol(struct seq_file *m, unsigned long address)
4283 {
4284 #ifdef CONFIG_KALLSYMS
4285         unsigned long offset, size;
4286         char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
4287 
4288         if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
4289                 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
4290                 if (modname[0])
4291                         seq_printf(m, " [%s]", modname);
4292                 return;
4293         }
4294 #endif
4295         seq_printf(m, "%p", (void *)address);
4296 }
4297 
4298 static int leaks_show(struct seq_file *m, void *p)
4299 {
4300         struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
4301         struct page *page;
4302         struct kmem_cache_node *n;
4303         const char *name;
4304         unsigned long *x = m->private;
4305         int node;
4306         int i;
4307 
4308         if (!(cachep->flags & SLAB_STORE_USER))
4309                 return 0;
4310         if (!(cachep->flags & SLAB_RED_ZONE))
4311                 return 0;
4312 
4313         /*
4314          * Set store_user_clean and start to grab stored user information
4315          * for all objects on this cache. If some alloc/free requests comes
4316          * during the processing, information would be wrong so restart
4317          * whole processing.
4318          */
4319         do {
4320                 set_store_user_clean(cachep);
4321                 drain_cpu_caches(cachep);
4322 
4323                 x[1] = 0;
4324 
4325                 for_each_kmem_cache_node(cachep, node, n) {
4326 
4327                         check_irq_on();
4328                         spin_lock_irq(&n->list_lock);
4329 
4330                         list_for_each_entry(page, &n->slabs_full, lru)
4331                                 handle_slab(x, cachep, page);
4332                         list_for_each_entry(page, &n->slabs_partial, lru)
4333                                 handle_slab(x, cachep, page);
4334                         spin_unlock_irq(&n->list_lock);
4335                 }
4336         } while (!is_store_user_clean(cachep));
4337 
4338         name = cachep->name;
4339         if (x[0] == x[1]) {
4340                 /* Increase the buffer size */
4341                 mutex_unlock(&slab_mutex);
4342                 m->private = kzalloc(x[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
4343                 if (!m->private) {
4344                         /* Too bad, we are really out */
4345                         m->private = x;
4346                         mutex_lock(&slab_mutex);
4347                         return -ENOMEM;
4348                 }
4349                 *(unsigned long *)m->private = x[0] * 2;
4350                 kfree(x);
4351                 mutex_lock(&slab_mutex);
4352                 /* Now make sure this entry will be retried */
4353                 m->count = m->size;
4354                 return 0;
4355         }
4356         for (i = 0; i < x[1]; i++) {
4357                 seq_printf(m, "%s: %lu ", name, x[2*i+3]);
4358                 show_symbol(m, x[2*i+2]);
4359                 seq_putc(m, '\n');
4360         }
4361 
4362         return 0;
4363 }
4364 
4365 static const struct seq_operations slabstats_op = {
4366         .start = slab_start,
4367         .next = slab_next,
4368         .stop = slab_stop,
4369         .show = leaks_show,
4370 };
4371 
4372 static int slabstats_open(struct inode *inode, struct file *file)
4373 {
4374         unsigned long *n;
4375 
4376         n = __seq_open_private(file, &slabstats_op, PAGE_SIZE);
4377         if (!n)
4378                 return -ENOMEM;
4379 
4380         *n = PAGE_SIZE / (2 * sizeof(unsigned long));
4381 
4382         return 0;
4383 }
4384 
4385 static const struct file_operations proc_slabstats_operations = {
4386         .open           = slabstats_open,
4387         .read           = seq_read,
4388         .llseek         = seq_lseek,
4389         .release        = seq_release_private,
4390 };
4391 #endif
4392 
4393 static int __init slab_proc_init(void)
4394 {
4395 #ifdef CONFIG_DEBUG_SLAB_LEAK
4396         proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
4397 #endif
4398         return 0;
4399 }
4400 module_init(slab_proc_init);
4401 #endif
4402 
4403 #ifdef CONFIG_HARDENED_USERCOPY
4404 /*
4405  * Rejects objects that are incorrectly sized.
4406  *
4407  * Returns NULL if check passes, otherwise const char * to name of cache
4408  * to indicate an error.
4409  */
4410 const char *__check_heap_object(const void *ptr, unsigned long n,
4411                                 struct page *page)
4412 {
4413         struct kmem_cache *cachep;
4414         unsigned int objnr;
4415         unsigned long offset;
4416 
4417         /* Find and validate object. */
4418         cachep = page->slab_cache;
4419         objnr = obj_to_index(cachep, page, (void *)ptr);
4420         BUG_ON(objnr >= cachep->num);
4421 
4422         /* Find offset within object. */
4423         offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep);
4424 
4425         /* Allow address range falling entirely within object size. */
4426         if (offset <= cachep->object_size && n <= cachep->object_size - offset)
4427                 return NULL;
4428 
4429         return cachep->name;
4430 }
4431 #endif /* CONFIG_HARDENED_USERCOPY */
4432 
4433 /**
4434  * ksize - get the actual amount of memory allocated for a given object
4435  * @objp: Pointer to the object
4436  *
4437  * kmalloc may internally round up allocations and return more memory
4438  * than requested. ksize() can be used to determine the actual amount of
4439  * memory allocated. The caller may use this additional memory, even though
4440  * a smaller amount of memory was initially specified with the kmalloc call.
4441  * The caller must guarantee that objp points to a valid object previously
4442  * allocated with either kmalloc() or kmem_cache_alloc(). The object
4443  * must not be freed during the duration of the call.
4444  */
4445 size_t ksize(const void *objp)
4446 {
4447         size_t size;
4448 
4449         BUG_ON(!objp);
4450         if (unlikely(objp == ZERO_SIZE_PTR))
4451                 return 0;
4452 
4453         size = virt_to_cache(objp)->object_size;
4454         /* We assume that ksize callers could use the whole allocated area,
4455          * so we need to unpoison this area.
4456          */
4457         kasan_unpoison_shadow(objp, size);
4458 
4459         return size;
4460 }
4461 EXPORT_SYMBOL(ksize);
4462 

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