Back to home page

LXR

 
 

    


0001 /*
0002  * linux/mm/slab.c
0003  * Written by Mark Hemment, 1996/97.
0004  * (markhe@nextd.demon.co.uk)
0005  *
0006  * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
0007  *
0008  * Major cleanup, different bufctl logic, per-cpu arrays
0009  *  (c) 2000 Manfred Spraul
0010  *
0011  * Cleanup, make the head arrays unconditional, preparation for NUMA
0012  *  (c) 2002 Manfred Spraul
0013  *
0014  * An implementation of the Slab Allocator as described in outline in;
0015  *  UNIX Internals: The New Frontiers by Uresh Vahalia
0016  *  Pub: Prentice Hall  ISBN 0-13-101908-2
0017  * or with a little more detail in;
0018  *  The Slab Allocator: An Object-Caching Kernel Memory Allocator
0019  *  Jeff Bonwick (Sun Microsystems).
0020  *  Presented at: USENIX Summer 1994 Technical Conference
0021  *
0022  * The memory is organized in caches, one cache for each object type.
0023  * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
0024  * Each cache consists out of many slabs (they are small (usually one
0025  * page long) and always contiguous), and each slab contains multiple
0026  * initialized objects.
0027  *
0028  * This means, that your constructor is used only for newly allocated
0029  * slabs and you must pass objects with the same initializations to
0030  * kmem_cache_free.
0031  *
0032  * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM,
0033  * normal). If you need a special memory type, then must create a new
0034  * cache for that memory type.
0035  *
0036  * In order to reduce fragmentation, the slabs are sorted in 3 groups:
0037  *   full slabs with 0 free objects
0038  *   partial slabs
0039  *   empty slabs with no allocated objects
0040  *
0041  * If partial slabs exist, then new allocations come from these slabs,
0042  * otherwise from empty slabs or new slabs are allocated.
0043  *
0044  * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache
0045  * during kmem_cache_destroy(). The caller must prevent concurrent allocs.
0046  *
0047  * Each cache has a short per-cpu head array, most allocs
0048  * and frees go into that array, and if that array overflows, then 1/2
0049  * of the entries in the array are given back into the global cache.
0050  * The head array is strictly LIFO and should improve the cache hit rates.
0051  * On SMP, it additionally reduces the spinlock operations.
0052  *
0053  * The c_cpuarray may not be read with enabled local interrupts -
0054  * it's changed with a smp_call_function().
0055  *
0056  * SMP synchronization:
0057  *  constructors and destructors are called without any locking.
0058  *  Several members in struct kmem_cache and struct slab never change, they
0059  *  are accessed without any locking.
0060  *  The per-cpu arrays are never accessed from the wrong cpu, no locking,
0061  *      and local interrupts are disabled so slab code is preempt-safe.
0062  *  The non-constant members are protected with a per-cache irq spinlock.
0063  *
0064  * Many thanks to Mark Hemment, who wrote another per-cpu slab patch
0065  * in 2000 - many ideas in the current implementation are derived from
0066  * his patch.
0067  *
0068  * Further notes from the original documentation:
0069  *
0070  * 11 April '97.  Started multi-threading - markhe
0071  *  The global cache-chain is protected by the mutex 'slab_mutex'.
0072  *  The sem is only needed when accessing/extending the cache-chain, which
0073  *  can never happen inside an interrupt (kmem_cache_create(),
0074  *  kmem_cache_shrink() and kmem_cache_reap()).
0075  *
0076  *  At present, each engine can be growing a cache.  This should be blocked.
0077  *
0078  * 15 March 2005. NUMA slab allocator.
0079  *  Shai Fultheim <shai@scalex86.org>.
0080  *  Shobhit Dayal <shobhit@calsoftinc.com>
0081  *  Alok N Kataria <alokk@calsoftinc.com>
0082  *  Christoph Lameter <christoph@lameter.com>
0083  *
0084  *  Modified the slab allocator to be node aware on NUMA systems.
0085  *  Each node has its own list of partial, free and full slabs.
0086  *  All object allocations for a node occur from node specific slab lists.
0087  */
0088 
0089 #include    <linux/slab.h>
0090 #include    <linux/mm.h>
0091 #include    <linux/poison.h>
0092 #include    <linux/swap.h>
0093 #include    <linux/cache.h>
0094 #include    <linux/interrupt.h>
0095 #include    <linux/init.h>
0096 #include    <linux/compiler.h>
0097 #include    <linux/cpuset.h>
0098 #include    <linux/proc_fs.h>
0099 #include    <linux/seq_file.h>
0100 #include    <linux/notifier.h>
0101 #include    <linux/kallsyms.h>
0102 #include    <linux/cpu.h>
0103 #include    <linux/sysctl.h>
0104 #include    <linux/module.h>
0105 #include    <linux/rcupdate.h>
0106 #include    <linux/string.h>
0107 #include    <linux/uaccess.h>
0108 #include    <linux/nodemask.h>
0109 #include    <linux/kmemleak.h>
0110 #include    <linux/mempolicy.h>
0111 #include    <linux/mutex.h>
0112 #include    <linux/fault-inject.h>
0113 #include    <linux/rtmutex.h>
0114 #include    <linux/reciprocal_div.h>
0115 #include    <linux/debugobjects.h>
0116 #include    <linux/kmemcheck.h>
0117 #include    <linux/memory.h>
0118 #include    <linux/prefetch.h>
0119 
0120 #include    <net/sock.h>
0121 
0122 #include    <asm/cacheflush.h>
0123 #include    <asm/tlbflush.h>
0124 #include    <asm/page.h>
0125 
0126 #include <trace/events/kmem.h>
0127 
0128 #include    "internal.h"
0129 
0130 #include    "slab.h"
0131 
0132 /*
0133  * DEBUG    - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
0134  *        0 for faster, smaller code (especially in the critical paths).
0135  *
0136  * STATS    - 1 to collect stats for /proc/slabinfo.
0137  *        0 for faster, smaller code (especially in the critical paths).
0138  *
0139  * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
0140  */
0141 
0142 #ifdef CONFIG_DEBUG_SLAB
0143 #define DEBUG       1
0144 #define STATS       1
0145 #define FORCED_DEBUG    1
0146 #else
0147 #define DEBUG       0
0148 #define STATS       0
0149 #define FORCED_DEBUG    0
0150 #endif
0151 
0152 /* Shouldn't this be in a header file somewhere? */
0153 #define BYTES_PER_WORD      sizeof(void *)
0154 #define REDZONE_ALIGN       max(BYTES_PER_WORD, __alignof__(unsigned long long))
0155 
0156 #ifndef ARCH_KMALLOC_FLAGS
0157 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
0158 #endif
0159 
0160 #define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \
0161                 <= SLAB_OBJ_MIN_SIZE) ? 1 : 0)
0162 
0163 #if FREELIST_BYTE_INDEX
0164 typedef unsigned char freelist_idx_t;
0165 #else
0166 typedef unsigned short freelist_idx_t;
0167 #endif
0168 
0169 #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1)
0170 
0171 /*
0172  * struct array_cache
0173  *
0174  * Purpose:
0175  * - LIFO ordering, to hand out cache-warm objects from _alloc
0176  * - reduce the number of linked list operations
0177  * - reduce spinlock operations
0178  *
0179  * The limit is stored in the per-cpu structure to reduce the data cache
0180  * footprint.
0181  *
0182  */
0183 struct array_cache {
0184     unsigned int avail;
0185     unsigned int limit;
0186     unsigned int batchcount;
0187     unsigned int touched;
0188     void *entry[];  /*
0189              * Must have this definition in here for the proper
0190              * alignment of array_cache. Also simplifies accessing
0191              * the entries.
0192              */
0193 };
0194 
0195 struct alien_cache {
0196     spinlock_t lock;
0197     struct array_cache ac;
0198 };
0199 
0200 /*
0201  * Need this for bootstrapping a per node allocator.
0202  */
0203 #define NUM_INIT_LISTS (2 * MAX_NUMNODES)
0204 static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS];
0205 #define CACHE_CACHE 0
0206 #define SIZE_NODE (MAX_NUMNODES)
0207 
0208 static int drain_freelist(struct kmem_cache *cache,
0209             struct kmem_cache_node *n, int tofree);
0210 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
0211             int node, struct list_head *list);
0212 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list);
0213 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
0214 static void cache_reap(struct work_struct *unused);
0215 
0216 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
0217                         void **list);
0218 static inline void fixup_slab_list(struct kmem_cache *cachep,
0219                 struct kmem_cache_node *n, struct page *page,
0220                 void **list);
0221 static int slab_early_init = 1;
0222 
0223 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
0224 
0225 static void kmem_cache_node_init(struct kmem_cache_node *parent)
0226 {
0227     INIT_LIST_HEAD(&parent->slabs_full);
0228     INIT_LIST_HEAD(&parent->slabs_partial);
0229     INIT_LIST_HEAD(&parent->slabs_free);
0230     parent->total_slabs = 0;
0231     parent->free_slabs = 0;
0232     parent->shared = NULL;
0233     parent->alien = NULL;
0234     parent->colour_next = 0;
0235     spin_lock_init(&parent->list_lock);
0236     parent->free_objects = 0;
0237     parent->free_touched = 0;
0238 }
0239 
0240 #define MAKE_LIST(cachep, listp, slab, nodeid)              \
0241     do {                                \
0242         INIT_LIST_HEAD(listp);                  \
0243         list_splice(&get_node(cachep, nodeid)->slab, listp);    \
0244     } while (0)
0245 
0246 #define MAKE_ALL_LISTS(cachep, ptr, nodeid)             \
0247     do {                                \
0248     MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid);  \
0249     MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
0250     MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid);  \
0251     } while (0)
0252 
0253 #define CFLGS_OBJFREELIST_SLAB  (0x40000000UL)
0254 #define CFLGS_OFF_SLAB      (0x80000000UL)
0255 #define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB)
0256 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
0257 
0258 #define BATCHREFILL_LIMIT   16
0259 /*
0260  * Optimization question: fewer reaps means less probability for unnessary
0261  * cpucache drain/refill cycles.
0262  *
0263  * OTOH the cpuarrays can contain lots of objects,
0264  * which could lock up otherwise freeable slabs.
0265  */
0266 #define REAPTIMEOUT_AC      (2*HZ)
0267 #define REAPTIMEOUT_NODE    (4*HZ)
0268 
0269 #if STATS
0270 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
0271 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
0272 #define STATS_INC_ALLOCED(x)    ((x)->num_allocations++)
0273 #define STATS_INC_GROWN(x)  ((x)->grown++)
0274 #define STATS_ADD_REAPED(x,y)   ((x)->reaped += (y))
0275 #define STATS_SET_HIGH(x)                       \
0276     do {                                \
0277         if ((x)->num_active > (x)->high_mark)           \
0278             (x)->high_mark = (x)->num_active;       \
0279     } while (0)
0280 #define STATS_INC_ERR(x)    ((x)->errors++)
0281 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
0282 #define STATS_INC_NODEFREES(x)  ((x)->node_frees++)
0283 #define STATS_INC_ACOVERFLOW(x)   ((x)->node_overflow++)
0284 #define STATS_SET_FREEABLE(x, i)                    \
0285     do {                                \
0286         if ((x)->max_freeable < i)              \
0287             (x)->max_freeable = i;              \
0288     } while (0)
0289 #define STATS_INC_ALLOCHIT(x)   atomic_inc(&(x)->allochit)
0290 #define STATS_INC_ALLOCMISS(x)  atomic_inc(&(x)->allocmiss)
0291 #define STATS_INC_FREEHIT(x)    atomic_inc(&(x)->freehit)
0292 #define STATS_INC_FREEMISS(x)   atomic_inc(&(x)->freemiss)
0293 #else
0294 #define STATS_INC_ACTIVE(x) do { } while (0)
0295 #define STATS_DEC_ACTIVE(x) do { } while (0)
0296 #define STATS_INC_ALLOCED(x)    do { } while (0)
0297 #define STATS_INC_GROWN(x)  do { } while (0)
0298 #define STATS_ADD_REAPED(x,y)   do { (void)(y); } while (0)
0299 #define STATS_SET_HIGH(x)   do { } while (0)
0300 #define STATS_INC_ERR(x)    do { } while (0)
0301 #define STATS_INC_NODEALLOCS(x) do { } while (0)
0302 #define STATS_INC_NODEFREES(x)  do { } while (0)
0303 #define STATS_INC_ACOVERFLOW(x)   do { } while (0)
0304 #define STATS_SET_FREEABLE(x, i) do { } while (0)
0305 #define STATS_INC_ALLOCHIT(x)   do { } while (0)
0306 #define STATS_INC_ALLOCMISS(x)  do { } while (0)
0307 #define STATS_INC_FREEHIT(x)    do { } while (0)
0308 #define STATS_INC_FREEMISS(x)   do { } while (0)
0309 #endif
0310 
0311 #if DEBUG
0312 
0313 /*
0314  * memory layout of objects:
0315  * 0        : objp
0316  * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
0317  *      the end of an object is aligned with the end of the real
0318  *      allocation. Catches writes behind the end of the allocation.
0319  * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
0320  *      redzone word.
0321  * cachep->obj_offset: The real object.
0322  * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
0323  * cachep->size - 1* BYTES_PER_WORD: last caller address
0324  *                  [BYTES_PER_WORD long]
0325  */
0326 static int obj_offset(struct kmem_cache *cachep)
0327 {
0328     return cachep->obj_offset;
0329 }
0330 
0331 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
0332 {
0333     BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
0334     return (unsigned long long*) (objp + obj_offset(cachep) -
0335                       sizeof(unsigned long long));
0336 }
0337 
0338 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
0339 {
0340     BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
0341     if (cachep->flags & SLAB_STORE_USER)
0342         return (unsigned long long *)(objp + cachep->size -
0343                           sizeof(unsigned long long) -
0344                           REDZONE_ALIGN);
0345     return (unsigned long long *) (objp + cachep->size -
0346                        sizeof(unsigned long long));
0347 }
0348 
0349 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
0350 {
0351     BUG_ON(!(cachep->flags & SLAB_STORE_USER));
0352     return (void **)(objp + cachep->size - BYTES_PER_WORD);
0353 }
0354 
0355 #else
0356 
0357 #define obj_offset(x)           0
0358 #define dbg_redzone1(cachep, objp)  ({BUG(); (unsigned long long *)NULL;})
0359 #define dbg_redzone2(cachep, objp)  ({BUG(); (unsigned long long *)NULL;})
0360 #define dbg_userword(cachep, objp)  ({BUG(); (void **)NULL;})
0361 
0362 #endif
0363 
0364 #ifdef CONFIG_DEBUG_SLAB_LEAK
0365 
0366 static inline bool is_store_user_clean(struct kmem_cache *cachep)
0367 {
0368     return atomic_read(&cachep->store_user_clean) == 1;
0369 }
0370 
0371 static inline void set_store_user_clean(struct kmem_cache *cachep)
0372 {
0373     atomic_set(&cachep->store_user_clean, 1);
0374 }
0375 
0376 static inline void set_store_user_dirty(struct kmem_cache *cachep)
0377 {
0378     if (is_store_user_clean(cachep))
0379         atomic_set(&cachep->store_user_clean, 0);
0380 }
0381 
0382 #else
0383 static inline void set_store_user_dirty(struct kmem_cache *cachep) {}
0384 
0385 #endif
0386 
0387 /*
0388  * Do not go above this order unless 0 objects fit into the slab or
0389  * overridden on the command line.
0390  */
0391 #define SLAB_MAX_ORDER_HI   1
0392 #define SLAB_MAX_ORDER_LO   0
0393 static int slab_max_order = SLAB_MAX_ORDER_LO;
0394 static bool slab_max_order_set __initdata;
0395 
0396 static inline struct kmem_cache *virt_to_cache(const void *obj)
0397 {
0398     struct page *page = virt_to_head_page(obj);
0399     return page->slab_cache;
0400 }
0401 
0402 static inline void *index_to_obj(struct kmem_cache *cache, struct page *page,
0403                  unsigned int idx)
0404 {
0405     return page->s_mem + cache->size * idx;
0406 }
0407 
0408 /*
0409  * We want to avoid an expensive divide : (offset / cache->size)
0410  *   Using the fact that size is a constant for a particular cache,
0411  *   we can replace (offset / cache->size) by
0412  *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
0413  */
0414 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
0415                     const struct page *page, void *obj)
0416 {
0417     u32 offset = (obj - page->s_mem);
0418     return reciprocal_divide(offset, cache->reciprocal_buffer_size);
0419 }
0420 
0421 #define BOOT_CPUCACHE_ENTRIES   1
0422 /* internal cache of cache description objs */
0423 static struct kmem_cache kmem_cache_boot = {
0424     .batchcount = 1,
0425     .limit = BOOT_CPUCACHE_ENTRIES,
0426     .shared = 1,
0427     .size = sizeof(struct kmem_cache),
0428     .name = "kmem_cache",
0429 };
0430 
0431 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
0432 
0433 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
0434 {
0435     return this_cpu_ptr(cachep->cpu_cache);
0436 }
0437 
0438 /*
0439  * Calculate the number of objects and left-over bytes for a given buffer size.
0440  */
0441 static unsigned int cache_estimate(unsigned long gfporder, size_t buffer_size,
0442         unsigned long flags, size_t *left_over)
0443 {
0444     unsigned int num;
0445     size_t slab_size = PAGE_SIZE << gfporder;
0446 
0447     /*
0448      * The slab management structure can be either off the slab or
0449      * on it. For the latter case, the memory allocated for a
0450      * slab is used for:
0451      *
0452      * - @buffer_size bytes for each object
0453      * - One freelist_idx_t for each object
0454      *
0455      * We don't need to consider alignment of freelist because
0456      * freelist will be at the end of slab page. The objects will be
0457      * at the correct alignment.
0458      *
0459      * If the slab management structure is off the slab, then the
0460      * alignment will already be calculated into the size. Because
0461      * the slabs are all pages aligned, the objects will be at the
0462      * correct alignment when allocated.
0463      */
0464     if (flags & (CFLGS_OBJFREELIST_SLAB | CFLGS_OFF_SLAB)) {
0465         num = slab_size / buffer_size;
0466         *left_over = slab_size % buffer_size;
0467     } else {
0468         num = slab_size / (buffer_size + sizeof(freelist_idx_t));
0469         *left_over = slab_size %
0470             (buffer_size + sizeof(freelist_idx_t));
0471     }
0472 
0473     return num;
0474 }
0475 
0476 #if DEBUG
0477 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
0478 
0479 static void __slab_error(const char *function, struct kmem_cache *cachep,
0480             char *msg)
0481 {
0482     pr_err("slab error in %s(): cache `%s': %s\n",
0483            function, cachep->name, msg);
0484     dump_stack();
0485     add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
0486 }
0487 #endif
0488 
0489 /*
0490  * By default on NUMA we use alien caches to stage the freeing of
0491  * objects allocated from other nodes. This causes massive memory
0492  * inefficiencies when using fake NUMA setup to split memory into a
0493  * large number of small nodes, so it can be disabled on the command
0494  * line
0495   */
0496 
0497 static int use_alien_caches __read_mostly = 1;
0498 static int __init noaliencache_setup(char *s)
0499 {
0500     use_alien_caches = 0;
0501     return 1;
0502 }
0503 __setup("noaliencache", noaliencache_setup);
0504 
0505 static int __init slab_max_order_setup(char *str)
0506 {
0507     get_option(&str, &slab_max_order);
0508     slab_max_order = slab_max_order < 0 ? 0 :
0509                 min(slab_max_order, MAX_ORDER - 1);
0510     slab_max_order_set = true;
0511 
0512     return 1;
0513 }
0514 __setup("slab_max_order=", slab_max_order_setup);
0515 
0516 #ifdef CONFIG_NUMA
0517 /*
0518  * Special reaping functions for NUMA systems called from cache_reap().
0519  * These take care of doing round robin flushing of alien caches (containing
0520  * objects freed on different nodes from which they were allocated) and the
0521  * flushing of remote pcps by calling drain_node_pages.
0522  */
0523 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
0524 
0525 static void init_reap_node(int cpu)
0526 {
0527     per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu),
0528                             node_online_map);
0529 }
0530 
0531 static void next_reap_node(void)
0532 {
0533     int node = __this_cpu_read(slab_reap_node);
0534 
0535     node = next_node_in(node, node_online_map);
0536     __this_cpu_write(slab_reap_node, node);
0537 }
0538 
0539 #else
0540 #define init_reap_node(cpu) do { } while (0)
0541 #define next_reap_node(void) do { } while (0)
0542 #endif
0543 
0544 /*
0545  * Initiate the reap timer running on the target CPU.  We run at around 1 to 2Hz
0546  * via the workqueue/eventd.
0547  * Add the CPU number into the expiration time to minimize the possibility of
0548  * the CPUs getting into lockstep and contending for the global cache chain
0549  * lock.
0550  */
0551 static void start_cpu_timer(int cpu)
0552 {
0553     struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
0554 
0555     if (reap_work->work.func == NULL) {
0556         init_reap_node(cpu);
0557         INIT_DEFERRABLE_WORK(reap_work, cache_reap);
0558         schedule_delayed_work_on(cpu, reap_work,
0559                     __round_jiffies_relative(HZ, cpu));
0560     }
0561 }
0562 
0563 static void init_arraycache(struct array_cache *ac, int limit, int batch)
0564 {
0565     /*
0566      * The array_cache structures contain pointers to free object.
0567      * However, when such objects are allocated or transferred to another
0568      * cache the pointers are not cleared and they could be counted as
0569      * valid references during a kmemleak scan. Therefore, kmemleak must
0570      * not scan such objects.
0571      */
0572     kmemleak_no_scan(ac);
0573     if (ac) {
0574         ac->avail = 0;
0575         ac->limit = limit;
0576         ac->batchcount = batch;
0577         ac->touched = 0;
0578     }
0579 }
0580 
0581 static struct array_cache *alloc_arraycache(int node, int entries,
0582                         int batchcount, gfp_t gfp)
0583 {
0584     size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache);
0585     struct array_cache *ac = NULL;
0586 
0587     ac = kmalloc_node(memsize, gfp, node);
0588     init_arraycache(ac, entries, batchcount);
0589     return ac;
0590 }
0591 
0592 static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep,
0593                     struct page *page, void *objp)
0594 {
0595     struct kmem_cache_node *n;
0596     int page_node;
0597     LIST_HEAD(list);
0598 
0599     page_node = page_to_nid(page);
0600     n = get_node(cachep, page_node);
0601 
0602     spin_lock(&n->list_lock);
0603     free_block(cachep, &objp, 1, page_node, &list);
0604     spin_unlock(&n->list_lock);
0605 
0606     slabs_destroy(cachep, &list);
0607 }
0608 
0609 /*
0610  * Transfer objects in one arraycache to another.
0611  * Locking must be handled by the caller.
0612  *
0613  * Return the number of entries transferred.
0614  */
0615 static int transfer_objects(struct array_cache *to,
0616         struct array_cache *from, unsigned int max)
0617 {
0618     /* Figure out how many entries to transfer */
0619     int nr = min3(from->avail, max, to->limit - to->avail);
0620 
0621     if (!nr)
0622         return 0;
0623 
0624     memcpy(to->entry + to->avail, from->entry + from->avail -nr,
0625             sizeof(void *) *nr);
0626 
0627     from->avail -= nr;
0628     to->avail += nr;
0629     return nr;
0630 }
0631 
0632 #ifndef CONFIG_NUMA
0633 
0634 #define drain_alien_cache(cachep, alien) do { } while (0)
0635 #define reap_alien(cachep, n) do { } while (0)
0636 
0637 static inline struct alien_cache **alloc_alien_cache(int node,
0638                         int limit, gfp_t gfp)
0639 {
0640     return NULL;
0641 }
0642 
0643 static inline void free_alien_cache(struct alien_cache **ac_ptr)
0644 {
0645 }
0646 
0647 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
0648 {
0649     return 0;
0650 }
0651 
0652 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
0653         gfp_t flags)
0654 {
0655     return NULL;
0656 }
0657 
0658 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
0659          gfp_t flags, int nodeid)
0660 {
0661     return NULL;
0662 }
0663 
0664 static inline gfp_t gfp_exact_node(gfp_t flags)
0665 {
0666     return flags & ~__GFP_NOFAIL;
0667 }
0668 
0669 #else   /* CONFIG_NUMA */
0670 
0671 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
0672 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
0673 
0674 static struct alien_cache *__alloc_alien_cache(int node, int entries,
0675                         int batch, gfp_t gfp)
0676 {
0677     size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache);
0678     struct alien_cache *alc = NULL;
0679 
0680     alc = kmalloc_node(memsize, gfp, node);
0681     init_arraycache(&alc->ac, entries, batch);
0682     spin_lock_init(&alc->lock);
0683     return alc;
0684 }
0685 
0686 static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
0687 {
0688     struct alien_cache **alc_ptr;
0689     size_t memsize = sizeof(void *) * nr_node_ids;
0690     int i;
0691 
0692     if (limit > 1)
0693         limit = 12;
0694     alc_ptr = kzalloc_node(memsize, gfp, node);
0695     if (!alc_ptr)
0696         return NULL;
0697 
0698     for_each_node(i) {
0699         if (i == node || !node_online(i))
0700             continue;
0701         alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp);
0702         if (!alc_ptr[i]) {
0703             for (i--; i >= 0; i--)
0704                 kfree(alc_ptr[i]);
0705             kfree(alc_ptr);
0706             return NULL;
0707         }
0708     }
0709     return alc_ptr;
0710 }
0711 
0712 static void free_alien_cache(struct alien_cache **alc_ptr)
0713 {
0714     int i;
0715 
0716     if (!alc_ptr)
0717         return;
0718     for_each_node(i)
0719         kfree(alc_ptr[i]);
0720     kfree(alc_ptr);
0721 }
0722 
0723 static void __drain_alien_cache(struct kmem_cache *cachep,
0724                 struct array_cache *ac, int node,
0725                 struct list_head *list)
0726 {
0727     struct kmem_cache_node *n = get_node(cachep, node);
0728 
0729     if (ac->avail) {
0730         spin_lock(&n->list_lock);
0731         /*
0732          * Stuff objects into the remote nodes shared array first.
0733          * That way we could avoid the overhead of putting the objects
0734          * into the free lists and getting them back later.
0735          */
0736         if (n->shared)
0737             transfer_objects(n->shared, ac, ac->limit);
0738 
0739         free_block(cachep, ac->entry, ac->avail, node, list);
0740         ac->avail = 0;
0741         spin_unlock(&n->list_lock);
0742     }
0743 }
0744 
0745 /*
0746  * Called from cache_reap() to regularly drain alien caches round robin.
0747  */
0748 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
0749 {
0750     int node = __this_cpu_read(slab_reap_node);
0751 
0752     if (n->alien) {
0753         struct alien_cache *alc = n->alien[node];
0754         struct array_cache *ac;
0755 
0756         if (alc) {
0757             ac = &alc->ac;
0758             if (ac->avail && spin_trylock_irq(&alc->lock)) {
0759                 LIST_HEAD(list);
0760 
0761                 __drain_alien_cache(cachep, ac, node, &list);
0762                 spin_unlock_irq(&alc->lock);
0763                 slabs_destroy(cachep, &list);
0764             }
0765         }
0766     }
0767 }
0768 
0769 static void drain_alien_cache(struct kmem_cache *cachep,
0770                 struct alien_cache **alien)
0771 {
0772     int i = 0;
0773     struct alien_cache *alc;
0774     struct array_cache *ac;
0775     unsigned long flags;
0776 
0777     for_each_online_node(i) {
0778         alc = alien[i];
0779         if (alc) {
0780             LIST_HEAD(list);
0781 
0782             ac = &alc->ac;
0783             spin_lock_irqsave(&alc->lock, flags);
0784             __drain_alien_cache(cachep, ac, i, &list);
0785             spin_unlock_irqrestore(&alc->lock, flags);
0786             slabs_destroy(cachep, &list);
0787         }
0788     }
0789 }
0790 
0791 static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
0792                 int node, int page_node)
0793 {
0794     struct kmem_cache_node *n;
0795     struct alien_cache *alien = NULL;
0796     struct array_cache *ac;
0797     LIST_HEAD(list);
0798 
0799     n = get_node(cachep, node);
0800     STATS_INC_NODEFREES(cachep);
0801     if (n->alien && n->alien[page_node]) {
0802         alien = n->alien[page_node];
0803         ac = &alien->ac;
0804         spin_lock(&alien->lock);
0805         if (unlikely(ac->avail == ac->limit)) {
0806             STATS_INC_ACOVERFLOW(cachep);
0807             __drain_alien_cache(cachep, ac, page_node, &list);
0808         }
0809         ac->entry[ac->avail++] = objp;
0810         spin_unlock(&alien->lock);
0811         slabs_destroy(cachep, &list);
0812     } else {
0813         n = get_node(cachep, page_node);
0814         spin_lock(&n->list_lock);
0815         free_block(cachep, &objp, 1, page_node, &list);
0816         spin_unlock(&n->list_lock);
0817         slabs_destroy(cachep, &list);
0818     }
0819     return 1;
0820 }
0821 
0822 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
0823 {
0824     int page_node = page_to_nid(virt_to_page(objp));
0825     int node = numa_mem_id();
0826     /*
0827      * Make sure we are not freeing a object from another node to the array
0828      * cache on this cpu.
0829      */
0830     if (likely(node == page_node))
0831         return 0;
0832 
0833     return __cache_free_alien(cachep, objp, node, page_node);
0834 }
0835 
0836 /*
0837  * Construct gfp mask to allocate from a specific node but do not reclaim or
0838  * warn about failures.
0839  */
0840 static inline gfp_t gfp_exact_node(gfp_t flags)
0841 {
0842     return (flags | __GFP_THISNODE | __GFP_NOWARN) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
0843 }
0844 #endif
0845 
0846 static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp)
0847 {
0848     struct kmem_cache_node *n;
0849 
0850     /*
0851      * Set up the kmem_cache_node for cpu before we can
0852      * begin anything. Make sure some other cpu on this
0853      * node has not already allocated this
0854      */
0855     n = get_node(cachep, node);
0856     if (n) {
0857         spin_lock_irq(&n->list_lock);
0858         n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount +
0859                 cachep->num;
0860         spin_unlock_irq(&n->list_lock);
0861 
0862         return 0;
0863     }
0864 
0865     n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
0866     if (!n)
0867         return -ENOMEM;
0868 
0869     kmem_cache_node_init(n);
0870     n->next_reap = jiffies + REAPTIMEOUT_NODE +
0871             ((unsigned long)cachep) % REAPTIMEOUT_NODE;
0872 
0873     n->free_limit =
0874         (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num;
0875 
0876     /*
0877      * The kmem_cache_nodes don't come and go as CPUs
0878      * come and go.  slab_mutex is sufficient
0879      * protection here.
0880      */
0881     cachep->node[node] = n;
0882 
0883     return 0;
0884 }
0885 
0886 #if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP)
0887 /*
0888  * Allocates and initializes node for a node on each slab cache, used for
0889  * either memory or cpu hotplug.  If memory is being hot-added, the kmem_cache_node
0890  * will be allocated off-node since memory is not yet online for the new node.
0891  * When hotplugging memory or a cpu, existing node are not replaced if
0892  * already in use.
0893  *
0894  * Must hold slab_mutex.
0895  */
0896 static int init_cache_node_node(int node)
0897 {
0898     int ret;
0899     struct kmem_cache *cachep;
0900 
0901     list_for_each_entry(cachep, &slab_caches, list) {
0902         ret = init_cache_node(cachep, node, GFP_KERNEL);
0903         if (ret)
0904             return ret;
0905     }
0906 
0907     return 0;
0908 }
0909 #endif
0910 
0911 static int setup_kmem_cache_node(struct kmem_cache *cachep,
0912                 int node, gfp_t gfp, bool force_change)
0913 {
0914     int ret = -ENOMEM;
0915     struct kmem_cache_node *n;
0916     struct array_cache *old_shared = NULL;
0917     struct array_cache *new_shared = NULL;
0918     struct alien_cache **new_alien = NULL;
0919     LIST_HEAD(list);
0920 
0921     if (use_alien_caches) {
0922         new_alien = alloc_alien_cache(node, cachep->limit, gfp);
0923         if (!new_alien)
0924             goto fail;
0925     }
0926 
0927     if (cachep->shared) {
0928         new_shared = alloc_arraycache(node,
0929             cachep->shared * cachep->batchcount, 0xbaadf00d, gfp);
0930         if (!new_shared)
0931             goto fail;
0932     }
0933 
0934     ret = init_cache_node(cachep, node, gfp);
0935     if (ret)
0936         goto fail;
0937 
0938     n = get_node(cachep, node);
0939     spin_lock_irq(&n->list_lock);
0940     if (n->shared && force_change) {
0941         free_block(cachep, n->shared->entry,
0942                 n->shared->avail, node, &list);
0943         n->shared->avail = 0;
0944     }
0945 
0946     if (!n->shared || force_change) {
0947         old_shared = n->shared;
0948         n->shared = new_shared;
0949         new_shared = NULL;
0950     }
0951 
0952     if (!n->alien) {
0953         n->alien = new_alien;
0954         new_alien = NULL;
0955     }
0956 
0957     spin_unlock_irq(&n->list_lock);
0958     slabs_destroy(cachep, &list);
0959 
0960     /*
0961      * To protect lockless access to n->shared during irq disabled context.
0962      * If n->shared isn't NULL in irq disabled context, accessing to it is
0963      * guaranteed to be valid until irq is re-enabled, because it will be
0964      * freed after synchronize_sched().
0965      */
0966     if (old_shared && force_change)
0967         synchronize_sched();
0968 
0969 fail:
0970     kfree(old_shared);
0971     kfree(new_shared);
0972     free_alien_cache(new_alien);
0973 
0974     return ret;
0975 }
0976 
0977 #ifdef CONFIG_SMP
0978 
0979 static void cpuup_canceled(long cpu)
0980 {
0981     struct kmem_cache *cachep;
0982     struct kmem_cache_node *n = NULL;
0983     int node = cpu_to_mem(cpu);
0984     const struct cpumask *mask = cpumask_of_node(node);
0985 
0986     list_for_each_entry(cachep, &slab_caches, list) {
0987         struct array_cache *nc;
0988         struct array_cache *shared;
0989         struct alien_cache **alien;
0990         LIST_HEAD(list);
0991 
0992         n = get_node(cachep, node);
0993         if (!n)
0994             continue;
0995 
0996         spin_lock_irq(&n->list_lock);
0997 
0998         /* Free limit for this kmem_cache_node */
0999         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);