The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/mm/slab.c

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    1 /*
    2  * linux/mm/slab.c
    3  * Written by Mark Hemment, 1996/97.
    4  * (markhe@nextd.demon.co.uk)
    5  *
    6  * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
    7  *
    8  * Major cleanup, different bufctl logic, per-cpu arrays
    9  *      (c) 2000 Manfred Spraul
   10  *
   11  * Cleanup, make the head arrays unconditional, preparation for NUMA
   12  *      (c) 2002 Manfred Spraul
   13  *
   14  * An implementation of the Slab Allocator as described in outline in;
   15  *      UNIX Internals: The New Frontiers by Uresh Vahalia
   16  *      Pub: Prentice Hall      ISBN 0-13-101908-2
   17  * or with a little more detail in;
   18  *      The Slab Allocator: An Object-Caching Kernel Memory Allocator
   19  *      Jeff Bonwick (Sun Microsystems).
   20  *      Presented at: USENIX Summer 1994 Technical Conference
   21  *
   22  * The memory is organized in caches, one cache for each object type.
   23  * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
   24  * Each cache consists out of many slabs (they are small (usually one
   25  * page long) and always contiguous), and each slab contains multiple
   26  * initialized objects.
   27  *
   28  * This means, that your constructor is used only for newly allocated
   29  * slabs and you must pass objects with the same initializations to
   30  * kmem_cache_free.
   31  *
   32  * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM,
   33  * normal). If you need a special memory type, then must create a new
   34  * cache for that memory type.
   35  *
   36  * In order to reduce fragmentation, the slabs are sorted in 3 groups:
   37  *   full slabs with 0 free objects
   38  *   partial slabs
   39  *   empty slabs with no allocated objects
   40  *
   41  * If partial slabs exist, then new allocations come from these slabs,
   42  * otherwise from empty slabs or new slabs are allocated.
   43  *
   44  * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache
   45  * during kmem_cache_destroy(). The caller must prevent concurrent allocs.
   46  *
   47  * Each cache has a short per-cpu head array, most allocs
   48  * and frees go into that array, and if that array overflows, then 1/2
   49  * of the entries in the array are given back into the global cache.
   50  * The head array is strictly LIFO and should improve the cache hit rates.
   51  * On SMP, it additionally reduces the spinlock operations.
   52  *
   53  * The c_cpuarray may not be read with enabled local interrupts -
   54  * it's changed with a smp_call_function().
   55  *
   56  * SMP synchronization:
   57  *  constructors and destructors are called without any locking.
   58  *  Several members in struct kmem_cache and struct slab never change, they
   59  *      are accessed without any locking.
   60  *  The per-cpu arrays are never accessed from the wrong cpu, no locking,
   61  *      and local interrupts are disabled so slab code is preempt-safe.
   62  *  The non-constant members are protected with a per-cache irq spinlock.
   63  *
   64  * Many thanks to Mark Hemment, who wrote another per-cpu slab patch
   65  * in 2000 - many ideas in the current implementation are derived from
   66  * his patch.
   67  *
   68  * Further notes from the original documentation:
   69  *
   70  * 11 April '97.  Started multi-threading - markhe
   71  *      The global cache-chain is protected by the mutex 'slab_mutex'.
   72  *      The sem is only needed when accessing/extending the cache-chain, which
   73  *      can never happen inside an interrupt (kmem_cache_create(),
   74  *      kmem_cache_shrink() and kmem_cache_reap()).
   75  *
   76  *      At present, each engine can be growing a cache.  This should be blocked.
   77  *
   78  * 15 March 2005. NUMA slab allocator.
   79  *      Shai Fultheim <shai@scalex86.org>.
   80  *      Shobhit Dayal <shobhit@calsoftinc.com>
   81  *      Alok N Kataria <alokk@calsoftinc.com>
   82  *      Christoph Lameter <christoph@lameter.com>
   83  *
   84  *      Modified the slab allocator to be node aware on NUMA systems.
   85  *      Each node has its own list of partial, free and full slabs.
   86  *      All object allocations for a node occur from node specific slab lists.
   87  */
   88 
   89 #include        <linux/slab.h>
   90 #include        <linux/mm.h>
   91 #include        <linux/poison.h>
   92 #include        <linux/swap.h>
   93 #include        <linux/cache.h>
   94 #include        <linux/interrupt.h>
   95 #include        <linux/init.h>
   96 #include        <linux/compiler.h>
   97 #include        <linux/cpuset.h>
   98 #include        <linux/proc_fs.h>
   99 #include        <linux/seq_file.h>
  100 #include        <linux/notifier.h>
  101 #include        <linux/kallsyms.h>
  102 #include        <linux/cpu.h>
  103 #include        <linux/sysctl.h>
  104 #include        <linux/module.h>
  105 #include        <linux/rcupdate.h>
  106 #include        <linux/string.h>
  107 #include        <linux/uaccess.h>
  108 #include        <linux/nodemask.h>
  109 #include        <linux/kmemleak.h>
  110 #include        <linux/mempolicy.h>
  111 #include        <linux/mutex.h>
  112 #include        <linux/fault-inject.h>
  113 #include        <linux/rtmutex.h>
  114 #include        <linux/reciprocal_div.h>
  115 #include        <linux/debugobjects.h>
  116 #include        <linux/kmemcheck.h>
  117 #include        <linux/memory.h>
  118 #include        <linux/prefetch.h>
  119 
  120 #include        <net/sock.h>
  121 
  122 #include        <asm/cacheflush.h>
  123 #include        <asm/tlbflush.h>
  124 #include        <asm/page.h>
  125 
  126 #include <trace/events/kmem.h>
  127 
  128 #include        "internal.h"
  129 
  130 #include        "slab.h"
  131 
  132 /*
  133  * DEBUG        - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
  134  *                0 for faster, smaller code (especially in the critical paths).
  135  *
  136  * STATS        - 1 to collect stats for /proc/slabinfo.
  137  *                0 for faster, smaller code (especially in the critical paths).
  138  *
  139  * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
  140  */
  141 
  142 #ifdef CONFIG_DEBUG_SLAB
  143 #define DEBUG           1
  144 #define STATS           1
  145 #define FORCED_DEBUG    1
  146 #else
  147 #define DEBUG           0
  148 #define STATS           0
  149 #define FORCED_DEBUG    0
  150 #endif
  151 
  152 /* Shouldn't this be in a header file somewhere? */
  153 #define BYTES_PER_WORD          sizeof(void *)
  154 #define REDZONE_ALIGN           max(BYTES_PER_WORD, __alignof__(unsigned long long))
  155 
  156 #ifndef ARCH_KMALLOC_FLAGS
  157 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
  158 #endif
  159 
  160 /*
  161  * true if a page was allocated from pfmemalloc reserves for network-based
  162  * swap
  163  */
  164 static bool pfmemalloc_active __read_mostly;
  165 
  166 /*
  167  * kmem_bufctl_t:
  168  *
  169  * Bufctl's are used for linking objs within a slab
  170  * linked offsets.
  171  *
  172  * This implementation relies on "struct page" for locating the cache &
  173  * slab an object belongs to.
  174  * This allows the bufctl structure to be small (one int), but limits
  175  * the number of objects a slab (not a cache) can contain when off-slab
  176  * bufctls are used. The limit is the size of the largest general cache
  177  * that does not use off-slab slabs.
  178  * For 32bit archs with 4 kB pages, is this 56.
  179  * This is not serious, as it is only for large objects, when it is unwise
  180  * to have too many per slab.
  181  * Note: This limit can be raised by introducing a general cache whose size
  182  * is less than 512 (PAGE_SIZE<<3), but greater than 256.
  183  */
  184 
  185 typedef unsigned int kmem_bufctl_t;
  186 #define BUFCTL_END      (((kmem_bufctl_t)(~0U))-0)
  187 #define BUFCTL_FREE     (((kmem_bufctl_t)(~0U))-1)
  188 #define BUFCTL_ACTIVE   (((kmem_bufctl_t)(~0U))-2)
  189 #define SLAB_LIMIT      (((kmem_bufctl_t)(~0U))-3)
  190 
  191 /*
  192  * struct slab_rcu
  193  *
  194  * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
  195  * arrange for kmem_freepages to be called via RCU.  This is useful if
  196  * we need to approach a kernel structure obliquely, from its address
  197  * obtained without the usual locking.  We can lock the structure to
  198  * stabilize it and check it's still at the given address, only if we
  199  * can be sure that the memory has not been meanwhile reused for some
  200  * other kind of object (which our subsystem's lock might corrupt).
  201  *
  202  * rcu_read_lock before reading the address, then rcu_read_unlock after
  203  * taking the spinlock within the structure expected at that address.
  204  */
  205 struct slab_rcu {
  206         struct rcu_head head;
  207         struct kmem_cache *cachep;
  208         void *addr;
  209 };
  210 
  211 /*
  212  * struct slab
  213  *
  214  * Manages the objs in a slab. Placed either at the beginning of mem allocated
  215  * for a slab, or allocated from an general cache.
  216  * Slabs are chained into three list: fully used, partial, fully free slabs.
  217  */
  218 struct slab {
  219         union {
  220                 struct {
  221                         struct list_head list;
  222                         unsigned long colouroff;
  223                         void *s_mem;            /* including colour offset */
  224                         unsigned int inuse;     /* num of objs active in slab */
  225                         kmem_bufctl_t free;
  226                         unsigned short nodeid;
  227                 };
  228                 struct slab_rcu __slab_cover_slab_rcu;
  229         };
  230 };
  231 
  232 /*
  233  * struct array_cache
  234  *
  235  * Purpose:
  236  * - LIFO ordering, to hand out cache-warm objects from _alloc
  237  * - reduce the number of linked list operations
  238  * - reduce spinlock operations
  239  *
  240  * The limit is stored in the per-cpu structure to reduce the data cache
  241  * footprint.
  242  *
  243  */
  244 struct array_cache {
  245         unsigned int avail;
  246         unsigned int limit;
  247         unsigned int batchcount;
  248         unsigned int touched;
  249         spinlock_t lock;
  250         void *entry[];  /*
  251                          * Must have this definition in here for the proper
  252                          * alignment of array_cache. Also simplifies accessing
  253                          * the entries.
  254                          *
  255                          * Entries should not be directly dereferenced as
  256                          * entries belonging to slabs marked pfmemalloc will
  257                          * have the lower bits set SLAB_OBJ_PFMEMALLOC
  258                          */
  259 };
  260 
  261 #define SLAB_OBJ_PFMEMALLOC     1
  262 static inline bool is_obj_pfmemalloc(void *objp)
  263 {
  264         return (unsigned long)objp & SLAB_OBJ_PFMEMALLOC;
  265 }
  266 
  267 static inline void set_obj_pfmemalloc(void **objp)
  268 {
  269         *objp = (void *)((unsigned long)*objp | SLAB_OBJ_PFMEMALLOC);
  270         return;
  271 }
  272 
  273 static inline void clear_obj_pfmemalloc(void **objp)
  274 {
  275         *objp = (void *)((unsigned long)*objp & ~SLAB_OBJ_PFMEMALLOC);
  276 }
  277 
  278 /*
  279  * bootstrap: The caches do not work without cpuarrays anymore, but the
  280  * cpuarrays are allocated from the generic caches...
  281  */
  282 #define BOOT_CPUCACHE_ENTRIES   1
  283 struct arraycache_init {
  284         struct array_cache cache;
  285         void *entries[BOOT_CPUCACHE_ENTRIES];
  286 };
  287 
  288 /*
  289  * The slab lists for all objects.
  290  */
  291 struct kmem_list3 {
  292         struct list_head slabs_partial; /* partial list first, better asm code */
  293         struct list_head slabs_full;
  294         struct list_head slabs_free;
  295         unsigned long free_objects;
  296         unsigned int free_limit;
  297         unsigned int colour_next;       /* Per-node cache coloring */
  298         spinlock_t list_lock;
  299         struct array_cache *shared;     /* shared per node */
  300         struct array_cache **alien;     /* on other nodes */
  301         unsigned long next_reap;        /* updated without locking */
  302         int free_touched;               /* updated without locking */
  303 };
  304 
  305 /*
  306  * Need this for bootstrapping a per node allocator.
  307  */
  308 #define NUM_INIT_LISTS (3 * MAX_NUMNODES)
  309 static struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
  310 #define CACHE_CACHE 0
  311 #define SIZE_AC MAX_NUMNODES
  312 #define SIZE_L3 (2 * MAX_NUMNODES)
  313 
  314 static int drain_freelist(struct kmem_cache *cache,
  315                         struct kmem_list3 *l3, int tofree);
  316 static void free_block(struct kmem_cache *cachep, void **objpp, int len,
  317                         int node);
  318 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
  319 static void cache_reap(struct work_struct *unused);
  320 
  321 /*
  322  * This function must be completely optimized away if a constant is passed to
  323  * it.  Mostly the same as what is in linux/slab.h except it returns an index.
  324  */
  325 static __always_inline int index_of(const size_t size)
  326 {
  327         extern void __bad_size(void);
  328 
  329         if (__builtin_constant_p(size)) {
  330                 int i = 0;
  331 
  332 #define CACHE(x) \
  333         if (size <=x) \
  334                 return i; \
  335         else \
  336                 i++;
  337 #include <linux/kmalloc_sizes.h>
  338 #undef CACHE
  339                 __bad_size();
  340         } else
  341                 __bad_size();
  342         return 0;
  343 }
  344 
  345 static int slab_early_init = 1;
  346 
  347 #define INDEX_AC index_of(sizeof(struct arraycache_init))
  348 #define INDEX_L3 index_of(sizeof(struct kmem_list3))
  349 
  350 static void kmem_list3_init(struct kmem_list3 *parent)
  351 {
  352         INIT_LIST_HEAD(&parent->slabs_full);
  353         INIT_LIST_HEAD(&parent->slabs_partial);
  354         INIT_LIST_HEAD(&parent->slabs_free);
  355         parent->shared = NULL;
  356         parent->alien = NULL;
  357         parent->colour_next = 0;
  358         spin_lock_init(&parent->list_lock);
  359         parent->free_objects = 0;
  360         parent->free_touched = 0;
  361 }
  362 
  363 #define MAKE_LIST(cachep, listp, slab, nodeid)                          \
  364         do {                                                            \
  365                 INIT_LIST_HEAD(listp);                                  \
  366                 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
  367         } while (0)
  368 
  369 #define MAKE_ALL_LISTS(cachep, ptr, nodeid)                             \
  370         do {                                                            \
  371         MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid);  \
  372         MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
  373         MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid);  \
  374         } while (0)
  375 
  376 #define CFLGS_OFF_SLAB          (0x80000000UL)
  377 #define OFF_SLAB(x)     ((x)->flags & CFLGS_OFF_SLAB)
  378 
  379 #define BATCHREFILL_LIMIT       16
  380 /*
  381  * Optimization question: fewer reaps means less probability for unnessary
  382  * cpucache drain/refill cycles.
  383  *
  384  * OTOH the cpuarrays can contain lots of objects,
  385  * which could lock up otherwise freeable slabs.
  386  */
  387 #define REAPTIMEOUT_CPUC        (2*HZ)
  388 #define REAPTIMEOUT_LIST3       (4*HZ)
  389 
  390 #if STATS
  391 #define STATS_INC_ACTIVE(x)     ((x)->num_active++)
  392 #define STATS_DEC_ACTIVE(x)     ((x)->num_active--)
  393 #define STATS_INC_ALLOCED(x)    ((x)->num_allocations++)
  394 #define STATS_INC_GROWN(x)      ((x)->grown++)
  395 #define STATS_ADD_REAPED(x,y)   ((x)->reaped += (y))
  396 #define STATS_SET_HIGH(x)                                               \
  397         do {                                                            \
  398                 if ((x)->num_active > (x)->high_mark)                   \
  399                         (x)->high_mark = (x)->num_active;               \
  400         } while (0)
  401 #define STATS_INC_ERR(x)        ((x)->errors++)
  402 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
  403 #define STATS_INC_NODEFREES(x)  ((x)->node_frees++)
  404 #define STATS_INC_ACOVERFLOW(x)   ((x)->node_overflow++)
  405 #define STATS_SET_FREEABLE(x, i)                                        \
  406         do {                                                            \
  407                 if ((x)->max_freeable < i)                              \
  408                         (x)->max_freeable = i;                          \
  409         } while (0)
  410 #define STATS_INC_ALLOCHIT(x)   atomic_inc(&(x)->allochit)
  411 #define STATS_INC_ALLOCMISS(x)  atomic_inc(&(x)->allocmiss)
  412 #define STATS_INC_FREEHIT(x)    atomic_inc(&(x)->freehit)
  413 #define STATS_INC_FREEMISS(x)   atomic_inc(&(x)->freemiss)
  414 #else
  415 #define STATS_INC_ACTIVE(x)     do { } while (0)
  416 #define STATS_DEC_ACTIVE(x)     do { } while (0)
  417 #define STATS_INC_ALLOCED(x)    do { } while (0)
  418 #define STATS_INC_GROWN(x)      do { } while (0)
  419 #define STATS_ADD_REAPED(x,y)   do { (void)(y); } while (0)
  420 #define STATS_SET_HIGH(x)       do { } while (0)
  421 #define STATS_INC_ERR(x)        do { } while (0)
  422 #define STATS_INC_NODEALLOCS(x) do { } while (0)
  423 #define STATS_INC_NODEFREES(x)  do { } while (0)
  424 #define STATS_INC_ACOVERFLOW(x)   do { } while (0)
  425 #define STATS_SET_FREEABLE(x, i) do { } while (0)
  426 #define STATS_INC_ALLOCHIT(x)   do { } while (0)
  427 #define STATS_INC_ALLOCMISS(x)  do { } while (0)
  428 #define STATS_INC_FREEHIT(x)    do { } while (0)
  429 #define STATS_INC_FREEMISS(x)   do { } while (0)
  430 #endif
  431 
  432 #if DEBUG
  433 
  434 /*
  435  * memory layout of objects:
  436  * 0            : objp
  437  * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
  438  *              the end of an object is aligned with the end of the real
  439  *              allocation. Catches writes behind the end of the allocation.
  440  * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
  441  *              redzone word.
  442  * cachep->obj_offset: The real object.
  443  * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
  444  * cachep->size - 1* BYTES_PER_WORD: last caller address
  445  *                                      [BYTES_PER_WORD long]
  446  */
  447 static int obj_offset(struct kmem_cache *cachep)
  448 {
  449         return cachep->obj_offset;
  450 }
  451 
  452 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
  453 {
  454         BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
  455         return (unsigned long long*) (objp + obj_offset(cachep) -
  456                                       sizeof(unsigned long long));
  457 }
  458 
  459 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
  460 {
  461         BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
  462         if (cachep->flags & SLAB_STORE_USER)
  463                 return (unsigned long long *)(objp + cachep->size -
  464                                               sizeof(unsigned long long) -
  465                                               REDZONE_ALIGN);
  466         return (unsigned long long *) (objp + cachep->size -
  467                                        sizeof(unsigned long long));
  468 }
  469 
  470 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
  471 {
  472         BUG_ON(!(cachep->flags & SLAB_STORE_USER));
  473         return (void **)(objp + cachep->size - BYTES_PER_WORD);
  474 }
  475 
  476 #else
  477 
  478 #define obj_offset(x)                   0
  479 #define dbg_redzone1(cachep, objp)      ({BUG(); (unsigned long long *)NULL;})
  480 #define dbg_redzone2(cachep, objp)      ({BUG(); (unsigned long long *)NULL;})
  481 #define dbg_userword(cachep, objp)      ({BUG(); (void **)NULL;})
  482 
  483 #endif
  484 
  485 /*
  486  * Do not go above this order unless 0 objects fit into the slab or
  487  * overridden on the command line.
  488  */
  489 #define SLAB_MAX_ORDER_HI       1
  490 #define SLAB_MAX_ORDER_LO       0
  491 static int slab_max_order = SLAB_MAX_ORDER_LO;
  492 static bool slab_max_order_set __initdata;
  493 
  494 static inline struct kmem_cache *virt_to_cache(const void *obj)
  495 {
  496         struct page *page = virt_to_head_page(obj);
  497         return page->slab_cache;
  498 }
  499 
  500 static inline struct slab *virt_to_slab(const void *obj)
  501 {
  502         struct page *page = virt_to_head_page(obj);
  503 
  504         VM_BUG_ON(!PageSlab(page));
  505         return page->slab_page;
  506 }
  507 
  508 static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
  509                                  unsigned int idx)
  510 {
  511         return slab->s_mem + cache->size * idx;
  512 }
  513 
  514 /*
  515  * We want to avoid an expensive divide : (offset / cache->size)
  516  *   Using the fact that size is a constant for a particular cache,
  517  *   we can replace (offset / cache->size) by
  518  *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
  519  */
  520 static inline unsigned int obj_to_index(const struct kmem_cache *cache,
  521                                         const struct slab *slab, void *obj)
  522 {
  523         u32 offset = (obj - slab->s_mem);
  524         return reciprocal_divide(offset, cache->reciprocal_buffer_size);
  525 }
  526 
  527 /*
  528  * These are the default caches for kmalloc. Custom caches can have other sizes.
  529  */
  530 struct cache_sizes malloc_sizes[] = {
  531 #define CACHE(x) { .cs_size = (x) },
  532 #include <linux/kmalloc_sizes.h>
  533         CACHE(ULONG_MAX)
  534 #undef CACHE
  535 };
  536 EXPORT_SYMBOL(malloc_sizes);
  537 
  538 /* Must match cache_sizes above. Out of line to keep cache footprint low. */
  539 struct cache_names {
  540         char *name;
  541         char *name_dma;
  542 };
  543 
  544 static struct cache_names __initdata cache_names[] = {
  545 #define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
  546 #include <linux/kmalloc_sizes.h>
  547         {NULL,}
  548 #undef CACHE
  549 };
  550 
  551 static struct arraycache_init initarray_generic =
  552     { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
  553 
  554 /* internal cache of cache description objs */
  555 static struct kmem_cache kmem_cache_boot = {
  556         .batchcount = 1,
  557         .limit = BOOT_CPUCACHE_ENTRIES,
  558         .shared = 1,
  559         .size = sizeof(struct kmem_cache),
  560         .name = "kmem_cache",
  561 };
  562 
  563 #define BAD_ALIEN_MAGIC 0x01020304ul
  564 
  565 #ifdef CONFIG_LOCKDEP
  566 
  567 /*
  568  * Slab sometimes uses the kmalloc slabs to store the slab headers
  569  * for other slabs "off slab".
  570  * The locking for this is tricky in that it nests within the locks
  571  * of all other slabs in a few places; to deal with this special
  572  * locking we put on-slab caches into a separate lock-class.
  573  *
  574  * We set lock class for alien array caches which are up during init.
  575  * The lock annotation will be lost if all cpus of a node goes down and
  576  * then comes back up during hotplug
  577  */
  578 static struct lock_class_key on_slab_l3_key;
  579 static struct lock_class_key on_slab_alc_key;
  580 
  581 static struct lock_class_key debugobj_l3_key;
  582 static struct lock_class_key debugobj_alc_key;
  583 
  584 static void slab_set_lock_classes(struct kmem_cache *cachep,
  585                 struct lock_class_key *l3_key, struct lock_class_key *alc_key,
  586                 int q)
  587 {
  588         struct array_cache **alc;
  589         struct kmem_list3 *l3;
  590         int r;
  591 
  592         l3 = cachep->nodelists[q];
  593         if (!l3)
  594                 return;
  595 
  596         lockdep_set_class(&l3->list_lock, l3_key);
  597         alc = l3->alien;
  598         /*
  599          * FIXME: This check for BAD_ALIEN_MAGIC
  600          * should go away when common slab code is taught to
  601          * work even without alien caches.
  602          * Currently, non NUMA code returns BAD_ALIEN_MAGIC
  603          * for alloc_alien_cache,
  604          */
  605         if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
  606                 return;
  607         for_each_node(r) {
  608                 if (alc[r])
  609                         lockdep_set_class(&alc[r]->lock, alc_key);
  610         }
  611 }
  612 
  613 static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
  614 {
  615         slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node);
  616 }
  617 
  618 static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
  619 {
  620         int node;
  621 
  622         for_each_online_node(node)
  623                 slab_set_debugobj_lock_classes_node(cachep, node);
  624 }
  625 
  626 static void init_node_lock_keys(int q)
  627 {
  628         struct cache_sizes *s = malloc_sizes;
  629 
  630         if (slab_state < UP)
  631                 return;
  632 
  633         for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) {
  634                 struct kmem_list3 *l3;
  635 
  636                 l3 = s->cs_cachep->nodelists[q];
  637                 if (!l3 || OFF_SLAB(s->cs_cachep))
  638                         continue;
  639 
  640                 slab_set_lock_classes(s->cs_cachep, &on_slab_l3_key,
  641                                 &on_slab_alc_key, q);
  642         }
  643 }
  644 
  645 static void on_slab_lock_classes_node(struct kmem_cache *cachep, int q)
  646 {
  647         struct kmem_list3 *l3;
  648         l3 = cachep->nodelists[q];
  649         if (!l3)
  650                 return;
  651 
  652         slab_set_lock_classes(cachep, &on_slab_l3_key,
  653                         &on_slab_alc_key, q);
  654 }
  655 
  656 static inline void on_slab_lock_classes(struct kmem_cache *cachep)
  657 {
  658         int node;
  659 
  660         VM_BUG_ON(OFF_SLAB(cachep));
  661         for_each_node(node)
  662                 on_slab_lock_classes_node(cachep, node);
  663 }
  664 
  665 static inline void init_lock_keys(void)
  666 {
  667         int node;
  668 
  669         for_each_node(node)
  670                 init_node_lock_keys(node);
  671 }
  672 #else
  673 static void init_node_lock_keys(int q)
  674 {
  675 }
  676 
  677 static inline void init_lock_keys(void)
  678 {
  679 }
  680 
  681 static inline void on_slab_lock_classes(struct kmem_cache *cachep)
  682 {
  683 }
  684 
  685 static inline void on_slab_lock_classes_node(struct kmem_cache *cachep, int node)
  686 {
  687 }
  688 
  689 static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
  690 {
  691 }
  692 
  693 static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
  694 {
  695 }
  696 #endif
  697 
  698 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
  699 
  700 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
  701 {
  702         return cachep->array[smp_processor_id()];
  703 }
  704 
  705 static inline struct kmem_cache *__find_general_cachep(size_t size,
  706                                                         gfp_t gfpflags)
  707 {
  708         struct cache_sizes *csizep = malloc_sizes;
  709 
  710 #if DEBUG
  711         /* This happens if someone tries to call
  712          * kmem_cache_create(), or __kmalloc(), before
  713          * the generic caches are initialized.
  714          */
  715         BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
  716 #endif
  717         if (!size)
  718                 return ZERO_SIZE_PTR;
  719 
  720         while (size > csizep->cs_size)
  721                 csizep++;
  722 
  723         /*
  724          * Really subtle: The last entry with cs->cs_size==ULONG_MAX
  725          * has cs_{dma,}cachep==NULL. Thus no special case
  726          * for large kmalloc calls required.
  727          */
  728 #ifdef CONFIG_ZONE_DMA
  729         if (unlikely(gfpflags & GFP_DMA))
  730                 return csizep->cs_dmacachep;
  731 #endif
  732         return csizep->cs_cachep;
  733 }
  734 
  735 static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
  736 {
  737         return __find_general_cachep(size, gfpflags);
  738 }
  739 
  740 static size_t slab_mgmt_size(size_t nr_objs, size_t align)
  741 {
  742         return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
  743 }
  744 
  745 /*
  746  * Calculate the number of objects and left-over bytes for a given buffer size.
  747  */
  748 static void cache_estimate(unsigned long gfporder, size_t buffer_size,
  749                            size_t align, int flags, size_t *left_over,
  750                            unsigned int *num)
  751 {
  752         int nr_objs;
  753         size_t mgmt_size;
  754         size_t slab_size = PAGE_SIZE << gfporder;
  755 
  756         /*
  757          * The slab management structure can be either off the slab or
  758          * on it. For the latter case, the memory allocated for a
  759          * slab is used for:
  760          *
  761          * - The struct slab
  762          * - One kmem_bufctl_t for each object
  763          * - Padding to respect alignment of @align
  764          * - @buffer_size bytes for each object
  765          *
  766          * If the slab management structure is off the slab, then the
  767          * alignment will already be calculated into the size. Because
  768          * the slabs are all pages aligned, the objects will be at the
  769          * correct alignment when allocated.
  770          */
  771         if (flags & CFLGS_OFF_SLAB) {
  772                 mgmt_size = 0;
  773                 nr_objs = slab_size / buffer_size;
  774 
  775                 if (nr_objs > SLAB_LIMIT)
  776                         nr_objs = SLAB_LIMIT;
  777         } else {
  778                 /*
  779                  * Ignore padding for the initial guess. The padding
  780                  * is at most @align-1 bytes, and @buffer_size is at
  781                  * least @align. In the worst case, this result will
  782                  * be one greater than the number of objects that fit
  783                  * into the memory allocation when taking the padding
  784                  * into account.
  785                  */
  786                 nr_objs = (slab_size - sizeof(struct slab)) /
  787                           (buffer_size + sizeof(kmem_bufctl_t));
  788 
  789                 /*
  790                  * This calculated number will be either the right
  791                  * amount, or one greater than what we want.
  792                  */
  793                 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
  794                        > slab_size)
  795                         nr_objs--;
  796 
  797                 if (nr_objs > SLAB_LIMIT)
  798                         nr_objs = SLAB_LIMIT;
  799 
  800                 mgmt_size = slab_mgmt_size(nr_objs, align);
  801         }
  802         *num = nr_objs;
  803         *left_over = slab_size - nr_objs*buffer_size - mgmt_size;
  804 }
  805 
  806 #if DEBUG
  807 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
  808 
  809 static void __slab_error(const char *function, struct kmem_cache *cachep,
  810                         char *msg)
  811 {
  812         printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
  813                function, cachep->name, msg);
  814         dump_stack();
  815         add_taint(TAINT_BAD_PAGE);
  816 }
  817 #endif
  818 
  819 /*
  820  * By default on NUMA we use alien caches to stage the freeing of
  821  * objects allocated from other nodes. This causes massive memory
  822  * inefficiencies when using fake NUMA setup to split memory into a
  823  * large number of small nodes, so it can be disabled on the command
  824  * line
  825   */
  826 
  827 static int use_alien_caches __read_mostly = 1;
  828 static int __init noaliencache_setup(char *s)
  829 {
  830         use_alien_caches = 0;
  831         return 1;
  832 }
  833 __setup("noaliencache", noaliencache_setup);
  834 
  835 static int __init slab_max_order_setup(char *str)
  836 {
  837         get_option(&str, &slab_max_order);
  838         slab_max_order = slab_max_order < 0 ? 0 :
  839                                 min(slab_max_order, MAX_ORDER - 1);
  840         slab_max_order_set = true;
  841 
  842         return 1;
  843 }
  844 __setup("slab_max_order=", slab_max_order_setup);
  845 
  846 #ifdef CONFIG_NUMA
  847 /*
  848  * Special reaping functions for NUMA systems called from cache_reap().
  849  * These take care of doing round robin flushing of alien caches (containing
  850  * objects freed on different nodes from which they were allocated) and the
  851  * flushing of remote pcps by calling drain_node_pages.
  852  */
  853 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
  854 
  855 static void init_reap_node(int cpu)
  856 {
  857         int node;
  858 
  859         node = next_node(cpu_to_mem(cpu), node_online_map);
  860         if (node == MAX_NUMNODES)
  861                 node = first_node(node_online_map);
  862 
  863         per_cpu(slab_reap_node, cpu) = node;
  864 }
  865 
  866 static void next_reap_node(void)
  867 {
  868         int node = __this_cpu_read(slab_reap_node);
  869 
  870         node = next_node(node, node_online_map);
  871         if (unlikely(node >= MAX_NUMNODES))
  872                 node = first_node(node_online_map);
  873         __this_cpu_write(slab_reap_node, node);
  874 }
  875 
  876 #else
  877 #define init_reap_node(cpu) do { } while (0)
  878 #define next_reap_node(void) do { } while (0)
  879 #endif
  880 
  881 /*
  882  * Initiate the reap timer running on the target CPU.  We run at around 1 to 2Hz
  883  * via the workqueue/eventd.
  884  * Add the CPU number into the expiration time to minimize the possibility of
  885  * the CPUs getting into lockstep and contending for the global cache chain
  886  * lock.
  887  */
  888 static void __cpuinit start_cpu_timer(int cpu)
  889 {
  890         struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
  891 
  892         /*
  893          * When this gets called from do_initcalls via cpucache_init(),
  894          * init_workqueues() has already run, so keventd will be setup
  895          * at that time.
  896          */
  897         if (keventd_up() && reap_work->work.func == NULL) {
  898                 init_reap_node(cpu);
  899                 INIT_DEFERRABLE_WORK(reap_work, cache_reap);
  900                 schedule_delayed_work_on(cpu, reap_work,
  901                                         __round_jiffies_relative(HZ, cpu));
  902         }
  903 }
  904 
  905 static struct array_cache *alloc_arraycache(int node, int entries,
  906                                             int batchcount, gfp_t gfp)
  907 {
  908         int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
  909         struct array_cache *nc = NULL;
  910 
  911         nc = kmalloc_node(memsize, gfp, node);
  912         /*
  913          * The array_cache structures contain pointers to free object.
  914          * However, when such objects are allocated or transferred to another
  915          * cache the pointers are not cleared and they could be counted as
  916          * valid references during a kmemleak scan. Therefore, kmemleak must
  917          * not scan such objects.
  918          */
  919         kmemleak_no_scan(nc);
  920         if (nc) {
  921                 nc->avail = 0;
  922                 nc->limit = entries;
  923                 nc->batchcount = batchcount;
  924                 nc->touched = 0;
  925                 spin_lock_init(&nc->lock);
  926         }
  927         return nc;
  928 }
  929 
  930 static inline bool is_slab_pfmemalloc(struct slab *slabp)
  931 {
  932         struct page *page = virt_to_page(slabp->s_mem);
  933 
  934         return PageSlabPfmemalloc(page);
  935 }
  936 
  937 /* Clears pfmemalloc_active if no slabs have pfmalloc set */
  938 static void recheck_pfmemalloc_active(struct kmem_cache *cachep,
  939                                                 struct array_cache *ac)
  940 {
  941         struct kmem_list3 *l3 = cachep->nodelists[numa_mem_id()];
  942         struct slab *slabp;
  943         unsigned long flags;
  944 
  945         if (!pfmemalloc_active)
  946                 return;
  947 
  948         spin_lock_irqsave(&l3->list_lock, flags);
  949         list_for_each_entry(slabp, &l3->slabs_full, list)
  950                 if (is_slab_pfmemalloc(slabp))
  951                         goto out;
  952 
  953         list_for_each_entry(slabp, &l3->slabs_partial, list)
  954                 if (is_slab_pfmemalloc(slabp))
  955                         goto out;
  956 
  957         list_for_each_entry(slabp, &l3->slabs_free, list)
  958                 if (is_slab_pfmemalloc(slabp))
  959                         goto out;
  960 
  961         pfmemalloc_active = false;
  962 out:
  963         spin_unlock_irqrestore(&l3->list_lock, flags);
  964 }
  965 
  966 static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
  967                                                 gfp_t flags, bool force_refill)
  968 {
  969         int i;
  970         void *objp = ac->entry[--ac->avail];
  971 
  972         /* Ensure the caller is allowed to use objects from PFMEMALLOC slab */
  973         if (unlikely(is_obj_pfmemalloc(objp))) {
  974                 struct kmem_list3 *l3;
  975 
  976                 if (gfp_pfmemalloc_allowed(flags)) {
  977                         clear_obj_pfmemalloc(&objp);
  978                         return objp;
  979                 }
  980 
  981                 /* The caller cannot use PFMEMALLOC objects, find another one */
  982                 for (i = 0; i < ac->avail; i++) {
  983                         /* If a !PFMEMALLOC object is found, swap them */
  984                         if (!is_obj_pfmemalloc(ac->entry[i])) {
  985                                 objp = ac->entry[i];
  986                                 ac->entry[i] = ac->entry[ac->avail];
  987                                 ac->entry[ac->avail] = objp;
  988                                 return objp;
  989                         }
  990                 }
  991 
  992                 /*
  993                  * If there are empty slabs on the slabs_free list and we are
  994                  * being forced to refill the cache, mark this one !pfmemalloc.
  995                  */
  996                 l3 = cachep->nodelists[numa_mem_id()];
  997                 if (!list_empty(&l3->slabs_free) && force_refill) {
  998                         struct slab *slabp = virt_to_slab(objp);
  999                         ClearPageSlabPfmemalloc(virt_to_head_page(slabp->s_mem));
 1000                         clear_obj_pfmemalloc(&objp);
 1001                         recheck_pfmemalloc_active(cachep, ac);
 1002                         return objp;
 1003                 }
 1004 
 1005                 /* No !PFMEMALLOC objects available */
 1006                 ac->avail++;
 1007                 objp = NULL;
 1008         }
 1009 
 1010         return objp;
 1011 }
 1012 
 1013 static inline void *ac_get_obj(struct kmem_cache *cachep,
 1014                         struct array_cache *ac, gfp_t flags, bool force_refill)
 1015 {
 1016         void *objp;
 1017 
 1018         if (unlikely(sk_memalloc_socks()))
 1019                 objp = __ac_get_obj(cachep, ac, flags, force_refill);
 1020         else
 1021                 objp = ac->entry[--ac->avail];
 1022 
 1023         return objp;
 1024 }
 1025 
 1026 static void *__ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
 1027                                                                 void *objp)
 1028 {
 1029         if (unlikely(pfmemalloc_active)) {
 1030                 /* Some pfmemalloc slabs exist, check if this is one */
 1031                 struct page *page = virt_to_head_page(objp);
 1032                 if (PageSlabPfmemalloc(page))
 1033                         set_obj_pfmemalloc(&objp);
 1034         }
 1035 
 1036         return objp;
 1037 }
 1038 
 1039 static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
 1040                                                                 void *objp)
 1041 {
 1042         if (unlikely(sk_memalloc_socks()))
 1043                 objp = __ac_put_obj(cachep, ac, objp);
 1044 
 1045         ac->entry[ac->avail++] = objp;
 1046 }
 1047 
 1048 /*
 1049  * Transfer objects in one arraycache to another.
 1050  * Locking must be handled by the caller.
 1051  *
 1052  * Return the number of entries transferred.
 1053  */
 1054 static int transfer_objects(struct array_cache *to,
 1055                 struct array_cache *from, unsigned int max)
 1056 {
 1057         /* Figure out how many entries to transfer */
 1058         int nr = min3(from->avail, max, to->limit - to->avail);
 1059 
 1060         if (!nr)
 1061                 return 0;
 1062 
 1063         memcpy(to->entry + to->avail, from->entry + from->avail -nr,
 1064                         sizeof(void *) *nr);
 1065 
 1066         from->avail -= nr;
 1067         to->avail += nr;
 1068         return nr;
 1069 }
 1070 
 1071 #ifndef CONFIG_NUMA
 1072 
 1073 #define drain_alien_cache(cachep, alien) do { } while (0)
 1074 #define reap_alien(cachep, l3) do { } while (0)
 1075 
 1076 static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
 1077 {
 1078         return (struct array_cache **)BAD_ALIEN_MAGIC;
 1079 }
 1080 
 1081 static inline void free_alien_cache(struct array_cache **ac_ptr)
 1082 {
 1083 }
 1084 
 1085 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
 1086 {
 1087         return 0;
 1088 }
 1089 
 1090 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
 1091                 gfp_t flags)
 1092 {
 1093         return NULL;
 1094 }
 1095 
 1096 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
 1097                  gfp_t flags, int nodeid)
 1098 {
 1099         return NULL;
 1100 }
 1101 
 1102 #else   /* CONFIG_NUMA */
 1103 
 1104 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
 1105 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
 1106 
 1107 static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
 1108 {
 1109         struct array_cache **ac_ptr;
 1110         int memsize = sizeof(void *) * nr_node_ids;
 1111         int i;
 1112 
 1113         if (limit > 1)
 1114                 limit = 12;
 1115         ac_ptr = kzalloc_node(memsize, gfp, node);
 1116         if (ac_ptr) {
 1117                 for_each_node(i) {
 1118                         if (i == node || !node_online(i))
 1119                                 continue;
 1120                         ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
 1121                         if (!ac_ptr[i]) {
 1122                                 for (i--; i >= 0; i--)
 1123                                         kfree(ac_ptr[i]);
 1124                                 kfree(ac_ptr);
 1125                                 return NULL;
 1126                         }
 1127                 }
 1128         }
 1129         return ac_ptr;
 1130 }
 1131 
 1132 static void free_alien_cache(struct array_cache **ac_ptr)
 1133 {
 1134         int i;
 1135 
 1136         if (!ac_ptr)
 1137                 return;
 1138         for_each_node(i)
 1139             kfree(ac_ptr[i]);
 1140         kfree(ac_ptr);
 1141 }
 1142 
 1143 static void __drain_alien_cache(struct kmem_cache *cachep,
 1144                                 struct array_cache *ac, int node)
 1145 {
 1146         struct kmem_list3 *rl3 = cachep->nodelists[node];
 1147 
 1148         if (ac->avail) {
 1149                 spin_lock(&rl3->list_lock);
 1150                 /*
 1151                  * Stuff objects into the remote nodes shared array first.
 1152                  * That way we could avoid the overhead of putting the objects
 1153                  * into the free lists and getting them back later.
 1154                  */
 1155                 if (rl3->shared)
 1156                         transfer_objects(rl3->shared, ac, ac->limit);
 1157 
 1158                 free_block(cachep, ac->entry, ac->avail, node);
 1159                 ac->avail = 0;
 1160                 spin_unlock(&rl3->list_lock);
 1161         }
 1162 }
 1163 
 1164 /*
 1165  * Called from cache_reap() to regularly drain alien caches round robin.
 1166  */
 1167 static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
 1168 {
 1169         int node = __this_cpu_read(slab_reap_node);
 1170 
 1171         if (l3->alien) {
 1172                 struct array_cache *ac = l3->alien[node];
 1173 
 1174                 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
 1175                         __drain_alien_cache(cachep, ac, node);
 1176                         spin_unlock_irq(&ac->lock);
 1177                 }
 1178         }
 1179 }
 1180 
 1181 static void drain_alien_cache(struct kmem_cache *cachep,
 1182                                 struct array_cache **alien)
 1183 {
 1184         int i = 0;
 1185         struct array_cache *ac;
 1186         unsigned long flags;
 1187 
 1188         for_each_online_node(i) {
 1189                 ac = alien[i];
 1190                 if (ac) {
 1191                         spin_lock_irqsave(&ac->lock, flags);
 1192                         __drain_alien_cache(cachep, ac, i);
 1193                         spin_unlock_irqrestore(&ac->lock, flags);
 1194                 }
 1195         }
 1196 }
 1197 
 1198 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
 1199 {
 1200         struct slab *slabp = virt_to_slab(objp);
 1201         int nodeid = slabp->nodeid;
 1202         struct kmem_list3 *l3;
 1203         struct array_cache *alien = NULL;
 1204         int node;
 1205 
 1206         node = numa_mem_id();
 1207 
 1208         /*
 1209          * Make sure we are not freeing a object from another node to the array
 1210          * cache on this cpu.
 1211          */
 1212         if (likely(slabp->nodeid == node))
 1213                 return 0;
 1214 
 1215         l3 = cachep->nodelists[node];
 1216         STATS_INC_NODEFREES(cachep);
 1217         if (l3->alien && l3->alien[nodeid]) {
 1218                 alien = l3->alien[nodeid];
 1219                 spin_lock(&alien->lock);
 1220                 if (unlikely(alien->avail == alien->limit)) {
 1221                         STATS_INC_ACOVERFLOW(cachep);
 1222                         __drain_alien_cache(cachep, alien, nodeid);
 1223                 }
 1224                 ac_put_obj(cachep, alien, objp);
 1225                 spin_unlock(&alien->lock);
 1226         } else {
 1227                 spin_lock(&(cachep->nodelists[nodeid])->list_lock);
 1228                 free_block(cachep, &objp, 1, nodeid);
 1229                 spin_unlock(&(cachep->nodelists[nodeid])->list_lock);
 1230         }
 1231         return 1;
 1232 }
 1233 #endif
 1234 
 1235 /*
 1236  * Allocates and initializes nodelists for a node on each slab cache, used for
 1237  * either memory or cpu hotplug.  If memory is being hot-added, the kmem_list3
 1238  * will be allocated off-node since memory is not yet online for the new node.
 1239  * When hotplugging memory or a cpu, existing nodelists are not replaced if
 1240  * already in use.
 1241  *
 1242  * Must hold slab_mutex.
 1243  */
 1244 static int init_cache_nodelists_node(int node)
 1245 {
 1246         struct kmem_cache *cachep;
 1247         struct kmem_list3 *l3;
 1248         const int memsize = sizeof(struct kmem_list3);
 1249 
 1250         list_for_each_entry(cachep, &slab_caches, list) {
 1251                 /*
 1252                  * Set up the size64 kmemlist for cpu before we can
 1253                  * begin anything. Make sure some other cpu on this
 1254                  * node has not already allocated this
 1255                  */
 1256                 if (!cachep->nodelists[node]) {
 1257                         l3 = kmalloc_node(memsize, GFP_KERNEL, node);
 1258                         if (!l3)
 1259                                 return -ENOMEM;
 1260                         kmem_list3_init(l3);
 1261                         l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
 1262                             ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
 1263 
 1264                         /*
 1265                          * The l3s don't come and go as CPUs come and
 1266                          * go.  slab_mutex is sufficient
 1267                          * protection here.
 1268                          */
 1269                         cachep->nodelists[node] = l3;
 1270                 }
 1271 
 1272                 spin_lock_irq(&cachep->nodelists[node]->list_lock);
 1273                 cachep->nodelists[node]->free_limit =
 1274                         (1 + nr_cpus_node(node)) *
 1275                         cachep->batchcount + cachep->num;
 1276                 spin_unlock_irq(&cachep->nodelists[node]->list_lock);
 1277         }
 1278         return 0;
 1279 }
 1280 
 1281 static void __cpuinit cpuup_canceled(long cpu)
 1282 {
 1283         struct kmem_cache *cachep;
 1284         struct kmem_list3 *l3 = NULL;
 1285         int node = cpu_to_mem(cpu);
 1286         const struct cpumask *mask = cpumask_of_node(node);
 1287 
 1288         list_for_each_entry(cachep, &slab_caches, list) {
 1289                 struct array_cache *nc;
 1290                 struct array_cache *shared;
 1291                 struct array_cache **alien;
 1292 
 1293                 /* cpu is dead; no one can alloc from it. */
 1294                 nc = cachep->array[cpu];
 1295                 cachep->array[cpu] = NULL;
 1296                 l3 = cachep->nodelists[node];
 1297 
 1298                 if (!l3)
 1299                         goto free_array_cache;
 1300 
 1301                 spin_lock_irq(&l3->list_lock);
 1302 
 1303                 /* Free limit for this kmem_list3 */
 1304                 l3->free_limit -= cachep->batchcount;
 1305                 if (nc)
 1306                         free_block(cachep, nc->entry, nc->avail, node);
 1307 
 1308                 if (!cpumask_empty(mask)) {
 1309                         spin_unlock_irq(&l3->list_lock);
 1310                         goto free_array_cache;
 1311                 }
 1312 
 1313                 shared = l3->shared;
 1314                 if (shared) {
 1315                         free_block(cachep, shared->entry,
 1316                                    shared->avail, node);
 1317                         l3->shared = NULL;
 1318                 }
 1319 
 1320                 alien = l3->alien;
 1321                 l3->alien = NULL;
 1322 
 1323                 spin_unlock_irq(&l3->list_lock);
 1324 
 1325                 kfree(shared);
 1326                 if (alien) {
 1327                         drain_alien_cache(cachep, alien);
 1328                         free_alien_cache(alien);
 1329                 }
 1330 free_array_cache:
 1331                 kfree(nc);
 1332         }
 1333         /*
 1334          * In the previous loop, all the objects were freed to
 1335          * the respective cache's slabs,  now we can go ahead and
 1336          * shrink each nodelist to its limit.
 1337          */
 1338         list_for_each_entry(cachep, &slab_caches, list) {
 1339                 l3 = cachep->nodelists[node];
 1340                 if (!l3)
 1341                         continue;
 1342                 drain_freelist(cachep, l3, l3->free_objects);
 1343         }
 1344 }
 1345 
 1346 static int __cpuinit cpuup_prepare(long cpu)
 1347 {
 1348         struct kmem_cache *cachep;
 1349         struct kmem_list3 *l3 = NULL;
 1350         int node = cpu_to_mem(cpu);
 1351         int err;
 1352 
 1353         /*
 1354          * We need to do this right in the beginning since
 1355          * alloc_arraycache's are going to use this list.
 1356          * kmalloc_node allows us to add the slab to the right
 1357          * kmem_list3 and not this cpu's kmem_list3
 1358          */
 1359         err = init_cache_nodelists_node(node);
 1360         if (err < 0)
 1361                 goto bad;
 1362 
 1363         /*
 1364          * Now we can go ahead with allocating the shared arrays and
 1365          * array caches
 1366          */
 1367         list_for_each_entry(cachep, &slab_caches, list) {
 1368                 struct array_cache *nc;
 1369                 struct array_cache *shared = NULL;
 1370                 struct array_cache **alien = NULL;
 1371 
 1372                 nc = alloc_arraycache(node, cachep->limit,
 1373                                         cachep->batchcount, GFP_KERNEL);
 1374                 if (!nc)
 1375                         goto bad;
 1376                 if (cachep->shared) {
 1377                         shared = alloc_arraycache(node,
 1378                                 cachep->shared * cachep->batchcount,
 1379                                 0xbaadf00d, GFP_KERNEL);
 1380                         if (!shared) {
 1381                                 kfree(nc);
 1382                                 goto bad;
 1383                         }
 1384                 }
 1385                 if (use_alien_caches) {
 1386                         alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
 1387                         if (!alien) {
 1388                                 kfree(shared);
 1389                                 kfree(nc);
 1390                                 goto bad;
 1391                         }
 1392                 }
 1393                 cachep->array[cpu] = nc;
 1394                 l3 = cachep->nodelists[node];
 1395                 BUG_ON(!l3);
 1396 
 1397                 spin_lock_irq(&l3->list_lock);
 1398                 if (!l3->shared) {
 1399                         /*
 1400                          * We are serialised from CPU_DEAD or
 1401                          * CPU_UP_CANCELLED by the cpucontrol lock
 1402                          */
 1403                         l3->shared = shared;
 1404                         shared = NULL;
 1405                 }
 1406 #ifdef CONFIG_NUMA
 1407                 if (!l3->alien) {
 1408                         l3->alien = alien;
 1409                         alien = NULL;
 1410                 }
 1411 #endif
 1412                 spin_unlock_irq(&l3->list_lock);
 1413                 kfree(shared);
 1414                 free_alien_cache(alien);
 1415                 if (cachep->flags & SLAB_DEBUG_OBJECTS)
 1416                         slab_set_debugobj_lock_classes_node(cachep, node);
 1417                 else if (!OFF_SLAB(cachep) &&
 1418                          !(cachep->flags & SLAB_DESTROY_BY_RCU))
 1419                         on_slab_lock_classes_node(cachep, node);
 1420         }
 1421         init_node_lock_keys(node);
 1422 
 1423         return 0;
 1424 bad:
 1425         cpuup_canceled(cpu);
 1426         return -ENOMEM;
 1427 }
 1428 
 1429 static int __cpuinit cpuup_callback(struct notifier_block *nfb,
 1430                                     unsigned long action, void *hcpu)
 1431 {
 1432         long cpu = (long)hcpu;
 1433         int err = 0;
 1434 
 1435         switch (action) {
 1436         case CPU_UP_PREPARE:
 1437         case CPU_UP_PREPARE_FROZEN:
 1438                 mutex_lock(&slab_mutex);
 1439                 err = cpuup_prepare(cpu);
 1440                 mutex_unlock(&slab_mutex);
 1441                 break;
 1442         case CPU_ONLINE:
 1443         case CPU_ONLINE_FROZEN:
 1444                 start_cpu_timer(cpu);
 1445                 break;
 1446 #ifdef CONFIG_HOTPLUG_CPU
 1447         case CPU_DOWN_PREPARE:
 1448         case CPU_DOWN_PREPARE_FROZEN:
 1449                 /*
 1450                  * Shutdown cache reaper. Note that the slab_mutex is
 1451                  * held so that if cache_reap() is invoked it cannot do
 1452                  * anything expensive but will only modify reap_work
 1453                  * and reschedule the timer.
 1454                 */
 1455                 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
 1456                 /* Now the cache_reaper is guaranteed to be not running. */
 1457                 per_cpu(slab_reap_work, cpu).work.func = NULL;
 1458                 break;
 1459         case CPU_DOWN_FAILED:
 1460         case CPU_DOWN_FAILED_FROZEN:
 1461                 start_cpu_timer(cpu);
 1462                 break;
 1463         case CPU_DEAD:
 1464         case CPU_DEAD_FROZEN:
 1465                 /*
 1466                  * Even if all the cpus of a node are down, we don't free the
 1467                  * kmem_list3 of any cache. This to avoid a race between
 1468                  * cpu_down, and a kmalloc allocation from another cpu for
 1469                  * memory from the node of the cpu going down.  The list3
 1470                  * structure is usually allocated from kmem_cache_create() and
 1471                  * gets destroyed at kmem_cache_destroy().
 1472                  */
 1473                 /* fall through */
 1474 #endif
 1475         case CPU_UP_CANCELED:
 1476         case CPU_UP_CANCELED_FROZEN:
 1477                 mutex_lock(&slab_mutex);
 1478                 cpuup_canceled(cpu);
 1479                 mutex_unlock(&slab_mutex);
 1480                 break;
 1481         }
 1482         return notifier_from_errno(err);
 1483 }
 1484 
 1485 static struct notifier_block __cpuinitdata cpucache_notifier = {
 1486         &cpuup_callback, NULL, 0
 1487 };
 1488 
 1489 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
 1490 /*
 1491  * Drains freelist for a node on each slab cache, used for memory hot-remove.
 1492  * Returns -EBUSY if all objects cannot be drained so that the node is not
 1493  * removed.
 1494  *
 1495  * Must hold slab_mutex.
 1496  */
 1497 static int __meminit drain_cache_nodelists_node(int node)
 1498 {
 1499         struct kmem_cache *cachep;
 1500         int ret = 0;
 1501 
 1502         list_for_each_entry(cachep, &slab_caches, list) {
 1503                 struct kmem_list3 *l3;
 1504 
 1505                 l3 = cachep->nodelists[node];
 1506                 if (!l3)
 1507                         continue;
 1508 
 1509                 drain_freelist(cachep, l3, l3->free_objects);
 1510 
 1511                 if (!list_empty(&l3->slabs_full) ||
 1512                     !list_empty(&l3->slabs_partial)) {
 1513                         ret = -EBUSY;
 1514                         break;
 1515                 }
 1516         }
 1517         return ret;
 1518 }
 1519 
 1520 static int __meminit slab_memory_callback(struct notifier_block *self,
 1521                                         unsigned long action, void *arg)
 1522 {
 1523         struct memory_notify *mnb = arg;
 1524         int ret = 0;
 1525         int nid;
 1526 
 1527         nid = mnb->status_change_nid;
 1528         if (nid < 0)
 1529                 goto out;
 1530 
 1531         switch (action) {
 1532         case MEM_GOING_ONLINE:
 1533                 mutex_lock(&slab_mutex);
 1534                 ret = init_cache_nodelists_node(nid);
 1535                 mutex_unlock(&slab_mutex);
 1536                 break;
 1537         case MEM_GOING_OFFLINE:
 1538                 mutex_lock(&slab_mutex);
 1539                 ret = drain_cache_nodelists_node(nid);
 1540                 mutex_unlock(&slab_mutex);
 1541                 break;
 1542         case MEM_ONLINE:
 1543         case MEM_OFFLINE:
 1544         case MEM_CANCEL_ONLINE:
 1545         case MEM_CANCEL_OFFLINE:
 1546                 break;
 1547         }
 1548 out:
 1549         return notifier_from_errno(ret);
 1550 }
 1551 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
 1552 
 1553 /*
 1554  * swap the static kmem_list3 with kmalloced memory
 1555  */
 1556 static void __init init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
 1557                                 int nodeid)
 1558 {
 1559         struct kmem_list3 *ptr;
 1560 
 1561         ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_NOWAIT, nodeid);
 1562         BUG_ON(!ptr);
 1563 
 1564         memcpy(ptr, list, sizeof(struct kmem_list3));
 1565         /*
 1566          * Do not assume that spinlocks can be initialized via memcpy:
 1567          */
 1568         spin_lock_init(&ptr->list_lock);
 1569 
 1570         MAKE_ALL_LISTS(cachep, ptr, nodeid);
 1571         cachep->nodelists[nodeid] = ptr;
 1572 }
 1573 
 1574 /*
 1575  * For setting up all the kmem_list3s for cache whose buffer_size is same as
 1576  * size of kmem_list3.
 1577  */
 1578 static void __init set_up_list3s(struct kmem_cache *cachep, int index)
 1579 {
 1580         int node;
 1581 
 1582         for_each_online_node(node) {
 1583                 cachep->nodelists[node] = &initkmem_list3[index + node];
 1584                 cachep->nodelists[node]->next_reap = jiffies +
 1585                     REAPTIMEOUT_LIST3 +
 1586                     ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
 1587         }
 1588 }
 1589 
 1590 /*
 1591  * The memory after the last cpu cache pointer is used for the
 1592  * the nodelists pointer.
 1593  */
 1594 static void setup_nodelists_pointer(struct kmem_cache *cachep)
 1595 {
 1596         cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids];
 1597 }
 1598 
 1599 /*
 1600  * Initialisation.  Called after the page allocator have been initialised and
 1601  * before smp_init().
 1602  */
 1603 void __init kmem_cache_init(void)
 1604 {
 1605         struct cache_sizes *sizes;
 1606         struct cache_names *names;
 1607         int i;
 1608 
 1609         kmem_cache = &kmem_cache_boot;
 1610         setup_nodelists_pointer(kmem_cache);
 1611 
 1612         if (num_possible_nodes() == 1)
 1613                 use_alien_caches = 0;
 1614 
 1615         for (i = 0; i < NUM_INIT_LISTS; i++)
 1616                 kmem_list3_init(&initkmem_list3[i]);
 1617 
 1618         set_up_list3s(kmem_cache, CACHE_CACHE);
 1619 
 1620         /*
 1621          * Fragmentation resistance on low memory - only use bigger
 1622          * page orders on machines with more than 32MB of memory if
 1623          * not overridden on the command line.
 1624          */
 1625         if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
 1626                 slab_max_order = SLAB_MAX_ORDER_HI;
 1627 
 1628         /* Bootstrap is tricky, because several objects are allocated
 1629          * from caches that do not exist yet:
 1630          * 1) initialize the kmem_cache cache: it contains the struct
 1631          *    kmem_cache structures of all caches, except kmem_cache itself:
 1632          *    kmem_cache is statically allocated.
 1633          *    Initially an __init data area is used for the head array and the
 1634          *    kmem_list3 structures, it's replaced with a kmalloc allocated
 1635          *    array at the end of the bootstrap.
 1636          * 2) Create the first kmalloc cache.
 1637          *    The struct kmem_cache for the new cache is allocated normally.
 1638          *    An __init data area is used for the head array.
 1639          * 3) Create the remaining kmalloc caches, with minimally sized
 1640          *    head arrays.
 1641          * 4) Replace the __init data head arrays for kmem_cache and the first
 1642          *    kmalloc cache with kmalloc allocated arrays.
 1643          * 5) Replace the __init data for kmem_list3 for kmem_cache and
 1644          *    the other cache's with kmalloc allocated memory.
 1645          * 6) Resize the head arrays of the kmalloc caches to their final sizes.
 1646          */
 1647 
 1648         /* 1) create the kmem_cache */
 1649 
 1650         /*
 1651          * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
 1652          */
 1653         create_boot_cache(kmem_cache, "kmem_cache",
 1654                 offsetof(struct kmem_cache, array[nr_cpu_ids]) +
 1655                                   nr_node_ids * sizeof(struct kmem_list3 *),
 1656                                   SLAB_HWCACHE_ALIGN);
 1657         list_add(&kmem_cache->list, &slab_caches);
 1658 
 1659         /* 2+3) create the kmalloc caches */
 1660         sizes = malloc_sizes;
 1661         names = cache_names;
 1662 
 1663         /*
 1664          * Initialize the caches that provide memory for the array cache and the
 1665          * kmem_list3 structures first.  Without this, further allocations will
 1666          * bug.
 1667          */
 1668 
 1669         sizes[INDEX_AC].cs_cachep = create_kmalloc_cache(names[INDEX_AC].name,
 1670                                         sizes[INDEX_AC].cs_size, ARCH_KMALLOC_FLAGS);
 1671 
 1672         if (INDEX_AC != INDEX_L3)
 1673                 sizes[INDEX_L3].cs_cachep =
 1674                         create_kmalloc_cache(names[INDEX_L3].name,
 1675                                 sizes[INDEX_L3].cs_size, ARCH_KMALLOC_FLAGS);
 1676 
 1677         slab_early_init = 0;
 1678 
 1679         while (sizes->cs_size != ULONG_MAX) {
 1680                 /*
 1681                  * For performance, all the general caches are L1 aligned.
 1682                  * This should be particularly beneficial on SMP boxes, as it
 1683                  * eliminates "false sharing".
 1684                  * Note for systems short on memory removing the alignment will
 1685                  * allow tighter packing of the smaller caches.
 1686                  */
 1687                 if (!sizes->cs_cachep)
 1688                         sizes->cs_cachep = create_kmalloc_cache(names->name,
 1689                                         sizes->cs_size, ARCH_KMALLOC_FLAGS);
 1690 
 1691 #ifdef CONFIG_ZONE_DMA
 1692                 sizes->cs_dmacachep = create_kmalloc_cache(
 1693                         names->name_dma, sizes->cs_size,
 1694                         SLAB_CACHE_DMA|ARCH_KMALLOC_FLAGS);
 1695 #endif
 1696                 sizes++;
 1697                 names++;
 1698         }
 1699         /* 4) Replace the bootstrap head arrays */
 1700         {
 1701                 struct array_cache *ptr;
 1702 
 1703                 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
 1704 
 1705                 memcpy(ptr, cpu_cache_get(kmem_cache),
 1706                        sizeof(struct arraycache_init));
 1707                 /*
 1708                  * Do not assume that spinlocks can be initialized via memcpy:
 1709                  */
 1710                 spin_lock_init(&ptr->lock);
 1711 
 1712                 kmem_cache->array[smp_processor_id()] = ptr;
 1713 
 1714                 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
 1715 
 1716                 BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
 1717                        != &initarray_generic.cache);
 1718                 memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
 1719                        sizeof(struct arraycache_init));
 1720                 /*
 1721                  * Do not assume that spinlocks can be initialized via memcpy:
 1722                  */
 1723                 spin_lock_init(&ptr->lock);
 1724 
 1725                 malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
 1726                     ptr;
 1727         }
 1728         /* 5) Replace the bootstrap kmem_list3's */
 1729         {
 1730                 int nid;
 1731 
 1732                 for_each_online_node(nid) {
 1733                         init_list(kmem_cache, &initkmem_list3[CACHE_CACHE + nid], nid);
 1734 
 1735                         init_list(malloc_sizes[INDEX_AC].cs_cachep,
 1736                                   &initkmem_list3[SIZE_AC + nid], nid);
 1737 
 1738                         if (INDEX_AC != INDEX_L3) {
 1739                                 init_list(malloc_sizes[INDEX_L3].cs_cachep,
 1740                                           &initkmem_list3[SIZE_L3 + nid], nid);
 1741                         }
 1742                 }
 1743         }
 1744 
 1745         slab_state = UP;
 1746 }
 1747 
 1748 void __init kmem_cache_init_late(void)
 1749 {
 1750         struct kmem_cache *cachep;
 1751 
 1752         slab_state = UP;
 1753 
 1754         /* 6) resize the head arrays to their final sizes */
 1755         mutex_lock(&slab_mutex);
 1756         list_for_each_entry(cachep, &slab_caches, list)
 1757                 if (enable_cpucache(cachep, GFP_NOWAIT))
 1758                         BUG();
 1759         mutex_unlock(&slab_mutex);
 1760 
 1761         /* Annotate slab for lockdep -- annotate the malloc caches */
 1762         init_lock_keys();
 1763 
 1764         /* Done! */
 1765         slab_state = FULL;
 1766 
 1767         /*
 1768          * Register a cpu startup notifier callback that initializes
 1769          * cpu_cache_get for all new cpus
 1770          */
 1771         register_cpu_notifier(&cpucache_notifier);
 1772 
 1773 #ifdef CONFIG_NUMA
 1774         /*
 1775          * Register a memory hotplug callback that initializes and frees
 1776          * nodelists.
 1777          */
 1778         hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
 1779 #endif
 1780 
 1781         /*
 1782          * The reap timers are started later, with a module init call: That part
 1783          * of the kernel is not yet operational.
 1784          */
 1785 }
 1786 
 1787 static int __init cpucache_init(void)
 1788 {
 1789         int cpu;
 1790 
 1791         /*
 1792          * Register the timers that return unneeded pages to the page allocator
 1793          */
 1794         for_each_online_cpu(cpu)
 1795                 start_cpu_timer(cpu);
 1796 
 1797         /* Done! */
 1798         slab_state = FULL;
 1799         return 0;
 1800 }
 1801 __initcall(cpucache_init);
 1802 
 1803 static noinline void
 1804 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
 1805 {
 1806         struct kmem_list3 *l3;
 1807         struct slab *slabp;
 1808         unsigned long flags;
 1809         int node;
 1810 
 1811         printk(KERN_WARNING
 1812                 "SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
 1813                 nodeid, gfpflags);
 1814         printk(KERN_WARNING "  cache: %s, object size: %d, order: %d\n",
 1815                 cachep->name, cachep->size, cachep->gfporder);
 1816 
 1817         for_each_online_node(node) {
 1818                 unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
 1819                 unsigned long active_slabs = 0, num_slabs = 0;
 1820 
 1821                 l3 = cachep->nodelists[node];
 1822                 if (!l3)
 1823                         continue;
 1824 
 1825                 spin_lock_irqsave(&l3->list_lock, flags);
 1826                 list_for_each_entry(slabp, &l3->slabs_full, list) {
 1827                         active_objs += cachep->num;
 1828                         active_slabs++;
 1829                 }
 1830                 list_for_each_entry(slabp, &l3->slabs_partial, list) {
 1831                         active_objs += slabp->inuse;
 1832                         active_slabs++;
 1833                 }
 1834                 list_for_each_entry(slabp, &l3->slabs_free, list)
 1835                         num_slabs++;
 1836 
 1837                 free_objects += l3->free_objects;
 1838                 spin_unlock_irqrestore(&l3->list_lock, flags);
 1839 
 1840                 num_slabs += active_slabs;
 1841                 num_objs = num_slabs * cachep->num;
 1842                 printk(KERN_WARNING
 1843                         "  node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
 1844                         node, active_slabs, num_slabs, active_objs, num_objs,
 1845                         free_objects);
 1846         }
 1847 }
 1848 
 1849 /*
 1850  * Interface to system's page allocator. No need to hold the cache-lock.
 1851  *
 1852  * If we requested dmaable memory, we will get it. Even if we
 1853  * did not request dmaable memory, we might get it, but that
 1854  * would be relatively rare and ignorable.
 1855  */
 1856 static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
 1857 {
 1858         struct page *page;
 1859         int nr_pages;
 1860         int i;
 1861 
 1862 #ifndef CONFIG_MMU
 1863         /*
 1864          * Nommu uses slab's for process anonymous memory allocations, and thus
 1865          * requires __GFP_COMP to properly refcount higher order allocations
 1866          */
 1867         flags |= __GFP_COMP;
 1868 #endif
 1869 
 1870         flags |= cachep->allocflags;
 1871         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
 1872                 flags |= __GFP_RECLAIMABLE;
 1873 
 1874         page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
 1875         if (!page) {
 1876                 if (!(flags & __GFP_NOWARN) && printk_ratelimit())
 1877                         slab_out_of_memory(cachep, flags, nodeid);
 1878                 return NULL;
 1879         }
 1880 
 1881         /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
 1882         if (unlikely(page->pfmemalloc))
 1883                 pfmemalloc_active = true;
 1884 
 1885         nr_pages = (1 << cachep->gfporder);
 1886         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
 1887                 add_zone_page_state(page_zone(page),
 1888                         NR_SLAB_RECLAIMABLE, nr_pages);
 1889         else
 1890                 add_zone_page_state(page_zone(page),
 1891                         NR_SLAB_UNRECLAIMABLE, nr_pages);
 1892         for (i = 0; i < nr_pages; i++) {
 1893                 __SetPageSlab(page + i);
 1894 
 1895                 if (page->pfmemalloc)
 1896                         SetPageSlabPfmemalloc(page + i);
 1897         }
 1898         memcg_bind_pages(cachep, cachep->gfporder);
 1899 
 1900         if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
 1901                 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
 1902 
 1903                 if (cachep->ctor)
 1904                         kmemcheck_mark_uninitialized_pages(page, nr_pages);
 1905                 else
 1906                         kmemcheck_mark_unallocated_pages(page, nr_pages);
 1907         }
 1908 
 1909         return page_address(page);
 1910 }
 1911 
 1912 /*
 1913  * Interface to system's page release.
 1914  */
 1915 static void kmem_freepages(struct kmem_cache *cachep, void *addr)
 1916 {
 1917         unsigned long i = (1 << cachep->gfporder);
 1918         struct page *page = virt_to_page(addr);
 1919         const unsigned long nr_freed = i;
 1920 
 1921         kmemcheck_free_shadow(page, cachep->gfporder);
 1922 
 1923         if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
 1924                 sub_zone_page_state(page_zone(page),
 1925                                 NR_SLAB_RECLAIMABLE, nr_freed);
 1926         else
 1927                 sub_zone_page_state(page_zone(page),
 1928                                 NR_SLAB_UNRECLAIMABLE, nr_freed);
 1929         while (i--) {
 1930                 BUG_ON(!PageSlab(page));
 1931                 __ClearPageSlabPfmemalloc(page);
 1932                 __ClearPageSlab(page);
 1933                 page++;
 1934         }
 1935 
 1936         memcg_release_pages(cachep, cachep->gfporder);
 1937         if (current->reclaim_state)
 1938                 current->reclaim_state->reclaimed_slab += nr_freed;
 1939         free_memcg_kmem_pages((unsigned long)addr, cachep->gfporder);
 1940 }
 1941 
 1942 static void kmem_rcu_free(struct rcu_head *head)
 1943 {
 1944         struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
 1945         struct kmem_cache *cachep = slab_rcu->cachep;
 1946 
 1947         kmem_freepages(cachep, slab_rcu->addr);
 1948         if (OFF_SLAB(cachep))
 1949                 kmem_cache_free(cachep->slabp_cache, slab_rcu);
 1950 }
 1951 
 1952 #if DEBUG
 1953 
 1954 #ifdef CONFIG_DEBUG_PAGEALLOC
 1955 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr,
 1956                             unsigned long caller)
 1957 {
 1958         int size = cachep->object_size;
 1959 
 1960         addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)];
 1961 
 1962         if (size < 5 * sizeof(unsigned long))
 1963                 return;
 1964 
 1965         *addr++ = 0x12345678;
 1966         *addr++ = caller;
 1967         *addr++ = smp_processor_id();
 1968         size -= 3 * sizeof(unsigned long);
 1969         {
 1970                 unsigned long *sptr = &caller;
 1971                 unsigned long svalue;
 1972 
 1973                 while (!kstack_end(sptr)) {
 1974                         svalue = *sptr++;
 1975                         if (kernel_text_address(svalue)) {
 1976                                 *addr++ = svalue;
 1977                                 size -= sizeof(unsigned long);
 1978                                 if (size <= sizeof(unsigned long))
 1979                                         break;
 1980                         }
 1981                 }
 1982 
 1983         }
 1984         *addr++ = 0x87654321;
 1985 }
 1986 #endif
 1987 
 1988 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
 1989 {
 1990         int size = cachep->object_size;
 1991         addr = &((char *)addr)[obj_offset(cachep)];
 1992 
 1993         memset(addr, val, size);
 1994         *(unsigned char *)(addr + size - 1) = POISON_END;
 1995 }
 1996 
 1997 static void dump_line(char *data, int offset, int limit)
 1998 {
 1999         int i;
 2000         unsigned char error = 0;
 2001         int bad_count = 0;
 2002 
 2003         printk(KERN_ERR "%03x: ", offset);
 2004         for (i = 0; i < limit; i++) {
 2005                 if (data[offset + i] != POISON_FREE) {
 2006                         error = data[offset + i];
 2007                         bad_count++;
 2008                 }
 2009         }
 2010         print_hex_dump(KERN_CONT, "", 0, 16, 1,
 2011                         &data[offset], limit, 1);
 2012 
 2013         if (bad_count == 1) {
 2014                 error ^= POISON_FREE;
 2015                 if (!(error & (error - 1))) {
 2016                         printk(KERN_ERR "Single bit error detected. Probably "
 2017                                         "bad RAM.\n");
 2018 #ifdef CONFIG_X86
 2019                         printk(KERN_ERR "Run memtest86+ or a similar memory "
 2020                                         "test tool.\n");
 2021 #else
 2022                         printk(KERN_ERR "Run a memory test tool.\n");
 2023 #endif
 2024                 }
 2025         }
 2026 }
 2027 #endif
 2028 
 2029 #if DEBUG
 2030 
 2031 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
 2032 {
 2033         int i, size;
 2034         char *realobj;
 2035 
 2036         if (cachep->flags & SLAB_RED_ZONE) {
 2037                 printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n",
 2038                         *dbg_redzone1(cachep, objp),
 2039                         *dbg_redzone2(cachep, objp));
 2040         }
 2041 
 2042         if (cachep->flags & SLAB_STORE_USER) {
 2043                 printk(KERN_ERR "Last user: [<%p>]",
 2044                         *dbg_userword(cachep, objp));
 2045                 print_symbol("(%s)",
 2046                                 (unsigned long)*dbg_userword(cachep, objp));
 2047                 printk("\n");
 2048         }
 2049         realobj = (char *)objp + obj_offset(cachep);
 2050         size = cachep->object_size;
 2051         for (i = 0; i < size && lines; i += 16, lines--) {
 2052                 int limit;
 2053                 limit = 16;
 2054                 if (i + limit > size)
 2055                         limit = size - i;
 2056                 dump_line(realobj, i, limit);
 2057         }
 2058 }
 2059 
 2060 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
 2061 {
 2062         char *realobj;
 2063         int size, i;
 2064         int lines = 0;
 2065 
 2066         realobj = (char *)objp + obj_offset(cachep);
 2067         size = cachep->object_size;
 2068 
 2069         for (i = 0; i < size; i++) {
 2070                 char exp = POISON_FREE;
 2071                 if (i == size - 1)
 2072                         exp = POISON_END;
 2073                 if (realobj[i] != exp) {
 2074                         int limit;
 2075                         /* Mismatch ! */
 2076                         /* Print header */
 2077                         if (lines == 0) {
 2078                                 printk(KERN_ERR
 2079                                         "Slab corruption (%s): %s start=%p, len=%d\n",
 2080                                         print_tainted(), cachep->name, realobj, size);
 2081                                 print_objinfo(cachep, objp, 0);
 2082                         }
 2083                         /* Hexdump the affected line */
 2084                         i = (i / 16) * 16;
 2085                         limit = 16;
 2086                         if (i + limit > size)
 2087                                 limit = size - i;
 2088                         dump_line(realobj, i, limit);
 2089                         i += 16;
 2090                         lines++;
 2091                         /* Limit to 5 lines */
 2092                         if (lines > 5)
 2093                                 break;
 2094                 }
 2095         }
 2096         if (lines != 0) {
 2097                 /* Print some data about the neighboring objects, if they
 2098                  * exist:
 2099                  */
 2100                 struct slab *slabp = virt_to_slab(objp);
 2101                 unsigned int objnr;
 2102 
 2103                 objnr = obj_to_index(cachep, slabp, objp);
 2104                 if (objnr) {
 2105                         objp = index_to_obj(cachep, slabp, objnr - 1);
 2106                         realobj = (char *)objp + obj_offset(cachep);
 2107                         printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
 2108                                realobj, size);
 2109                         print_objinfo(cachep, objp, 2);
 2110                 }
 2111                 if (objnr + 1 < cachep->num) {
 2112                         objp = index_to_obj(cachep, slabp, objnr + 1);
 2113                         realobj = (char *)objp + obj_offset(cachep);
 2114                         printk(KERN_ERR "Next obj: start=%p, len=%d\n",
 2115                                realobj, size);
 2116                         print_objinfo(cachep, objp, 2);
 2117                 }
 2118         }
 2119 }
 2120 #endif
 2121 
 2122 #if DEBUG
 2123 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
 2124 {
 2125         int i;
 2126         for (i = 0; i < cachep->num; i++) {
 2127                 void *objp = index_to_obj(cachep, slabp, i);
 2128 
 2129                 if (cachep->flags & SLAB_POISON) {
 2130 #ifdef CONFIG_DEBUG_PAGEALLOC
 2131                         if (cachep->size % PAGE_SIZE == 0 &&
 2132                                         OFF_SLAB(cachep))
 2133                                 kernel_map_pages(virt_to_page(objp),
 2134                                         cachep->size / PAGE_SIZE, 1);
 2135                         else
 2136                                 check_poison_obj(cachep, objp);
 2137 #else
 2138                         check_poison_obj(cachep, objp);
 2139 #endif
 2140                 }
 2141                 if (cachep->flags & SLAB_RED_ZONE) {
 2142                         if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
 2143                                 slab_error(cachep, "start of a freed object "
 2144                                            "was overwritten");
 2145                         if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
 2146                                 slab_error(cachep, "end of a freed object "
 2147                                            "was overwritten");
 2148                 }
 2149         }
 2150 }
 2151 #else
 2152 static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
 2153 {
 2154 }
 2155 #endif
 2156 
 2157 /**
 2158  * slab_destroy - destroy and release all objects in a slab
 2159  * @cachep: cache pointer being destroyed
 2160  * @slabp: slab pointer being destroyed
 2161  *
 2162  * Destroy all the objs in a slab, and release the mem back to the system.
 2163  * Before calling the slab must have been unlinked from the cache.  The
 2164  * cache-lock is not held/needed.
 2165  */
 2166 static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp)
 2167 {
 2168         void *addr = slabp->s_mem - slabp->colouroff;
 2169 
 2170         slab_destroy_debugcheck(cachep, slabp);
 2171         if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
 2172                 struct slab_rcu *slab_rcu;
 2173 
 2174                 slab_rcu = (struct slab_rcu *)slabp;
 2175                 slab_rcu->cachep = cachep;
 2176                 slab_rcu->addr = addr;
 2177                 call_rcu(&slab_rcu->head, kmem_rcu_free);
 2178         } else {
 2179                 kmem_freepages(cachep, addr);
 2180                 if (OFF_SLAB(cachep))
 2181                         kmem_cache_free(cachep->slabp_cache, slabp);
 2182         }
 2183 }
 2184 
 2185 /**
 2186  * calculate_slab_order - calculate size (page order) of slabs
 2187  * @cachep: pointer to the cache that is being created
 2188  * @size: size of objects to be created in this cache.
 2189  * @align: required alignment for the objects.
 2190  * @flags: slab allocation flags
 2191  *
 2192  * Also calculates the number of objects per slab.
 2193  *
 2194  * This could be made much more intelligent.  For now, try to avoid using
 2195  * high order pages for slabs.  When the gfp() functions are more friendly
 2196  * towards high-order requests, this should be changed.
 2197  */
 2198 static size_t calculate_slab_order(struct kmem_cache *cachep,
 2199                         size_t size, size_t align, unsigned long flags)
 2200 {
 2201         unsigned long offslab_limit;
 2202         size_t left_over = 0;
 2203         int gfporder;
 2204 
 2205         for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
 2206                 unsigned int num;
 2207                 size_t remainder;
 2208 
 2209                 cache_estimate(gfporder, size, align, flags, &remainder, &num);
 2210                 if (!num)
 2211                         continue;
 2212 
 2213                 if (flags & CFLGS_OFF_SLAB) {
 2214                         /*
 2215                          * Max number of objs-per-slab for caches which
 2216                          * use off-slab slabs. Needed to avoid a possible
 2217                          * looping condition in cache_grow().
 2218                          */
 2219                         offslab_limit = size - sizeof(struct slab);
 2220                         offslab_limit /= sizeof(kmem_bufctl_t);
 2221 
 2222                         if (num > offslab_limit)
 2223                                 break;
 2224                 }
 2225 
 2226                 /* Found something acceptable - save it away */
 2227                 cachep->num = num;
 2228                 cachep->gfporder = gfporder;
 2229                 left_over = remainder;
 2230 
 2231                 /*
 2232                  * A VFS-reclaimable slab tends to have most allocations
 2233                  * as GFP_NOFS and we really don't want to have to be allocating
 2234                  * higher-order pages when we are unable to shrink dcache.
 2235                  */
 2236                 if (flags & SLAB_RECLAIM_ACCOUNT)
 2237                         break;
 2238 
 2239                 /*
 2240                  * Large number of objects is good, but very large slabs are
 2241                  * currently bad for the gfp()s.
 2242                  */
 2243                 if (gfporder >= slab_max_order)
 2244                         break;
 2245 
 2246                 /*
 2247                  * Acceptable internal fragmentation?
 2248                  */
 2249                 if (left_over * 8 <= (PAGE_SIZE << gfporder))
 2250                         break;
 2251         }
 2252         return left_over;
 2253 }
 2254 
 2255 static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
 2256 {
 2257         if (slab_state >= FULL)
 2258                 return enable_cpucache(cachep, gfp);
 2259 
 2260         if (slab_state == DOWN) {
 2261                 /*
 2262                  * Note: Creation of first cache (kmem_cache).
 2263                  * The setup_list3s is taken care
 2264                  * of by the caller of __kmem_cache_create
 2265                  */
 2266                 cachep->array[smp_processor_id()] = &initarray_generic.cache;
 2267                 slab_state = PARTIAL;
 2268         } else if (slab_state == PARTIAL) {
 2269                 /*
 2270                  * Note: the second kmem_cache_create must create the cache
 2271                  * that's used by kmalloc(24), otherwise the creation of
 2272                  * further caches will BUG().
 2273                  */
 2274                 cachep->array[smp_processor_id()] = &initarray_generic.cache;
 2275 
 2276                 /*
 2277                  * If the cache that's used by kmalloc(sizeof(kmem_list3)) is
 2278                  * the second cache, then we need to set up all its list3s,
 2279                  * otherwise the creation of further caches will BUG().
 2280                  */
 2281                 set_up_list3s(cachep, SIZE_AC);
 2282                 if (INDEX_AC == INDEX_L3)
 2283                         slab_state = PARTIAL_L3;
 2284                 else
 2285                         slab_state = PARTIAL_ARRAYCACHE;
 2286         } else {
 2287                 /* Remaining boot caches */
 2288                 cachep->array[smp_processor_id()] =
 2289                         kmalloc(sizeof(struct arraycache_init), gfp);
 2290 
 2291                 if (slab_state == PARTIAL_ARRAYCACHE) {
 2292                         set_up_list3s(cachep, SIZE_L3);
 2293                         slab_state = PARTIAL_L3;
 2294                 } else {
 2295                         int node;
 2296                         for_each_online_node(node) {
 2297                                 cachep->nodelists[node] =
 2298                                     kmalloc_node(sizeof(struct kmem_list3),
 2299                                                 gfp, node);
 2300                                 BUG_ON(!cachep->nodelists[node]);
 2301                                 kmem_list3_init(cachep->nodelists[node]);
 2302                         }
 2303                 }
 2304         }
 2305         cachep->nodelists[numa_mem_id()]->next_reap =
 2306                         jiffies + REAPTIMEOUT_LIST3 +
 2307                         ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
 2308 
 2309         cpu_cache_get(cachep)->avail = 0;
 2310         cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
 2311         cpu_cache_get(cachep)->batchcount = 1;
 2312         cpu_cache_get(cachep)->touched = 0;
 2313         cachep->batchcount = 1;
 2314         cachep->limit = BOOT_CPUCACHE_ENTRIES;
 2315         return 0;
 2316 }
 2317 
 2318 /**
 2319  * __kmem_cache_create - Create a cache.
 2320  * @cachep: cache management descriptor
 2321  * @flags: SLAB flags
 2322  *
 2323  * Returns a ptr to the cache on success, NULL on failure.
 2324  * Cannot be called within a int, but can be interrupted.
 2325  * The @ctor is run when new pages are allocated by the cache.
 2326  *
 2327  * The flags are
 2328  *
 2329  * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
 2330  * to catch references to uninitialised memory.
 2331  *
 2332  * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
 2333  * for buffer overruns.
 2334  *
 2335  * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
 2336  * cacheline.  This can be beneficial if you're counting cycles as closely
 2337  * as davem.
 2338  */
 2339 int
 2340 __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags)
 2341 {
 2342         size_t left_over, slab_size, ralign;
 2343         gfp_t gfp;
 2344         int err;
 2345         size_t size = cachep->size;
 2346 
 2347 #if DEBUG
 2348 #if FORCED_DEBUG
 2349         /*
 2350          * Enable redzoning and last user accounting, except for caches with
 2351          * large objects, if the increased size would increase the object size
 2352          * above the next power of two: caches with object sizes just above a
 2353          * power of two have a significant amount of internal fragmentation.
 2354          */
 2355         if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
 2356                                                 2 * sizeof(unsigned long long)))
 2357                 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
 2358         if (!(flags & SLAB_DESTROY_BY_RCU))
 2359                 flags |= SLAB_POISON;
 2360 #endif
 2361         if (flags & SLAB_DESTROY_BY_RCU)
 2362                 BUG_ON(flags & SLAB_POISON);
 2363 #endif
 2364 
 2365         /*
 2366          * Check that size is in terms of words.  This is needed to avoid
 2367          * unaligned accesses for some archs when redzoning is used, and makes
 2368          * sure any on-slab bufctl's are also correctly aligned.
 2369          */
 2370         if (size & (BYTES_PER_WORD - 1)) {
 2371                 size += (BYTES_PER_WORD - 1);
 2372                 size &= ~(BYTES_PER_WORD - 1);
 2373         }
 2374 
 2375         /*
 2376          * Redzoning and user store require word alignment or possibly larger.
 2377          * Note this will be overridden by architecture or caller mandated
 2378          * alignment if either is greater than BYTES_PER_WORD.
 2379          */
 2380         if (flags & SLAB_STORE_USER)
 2381                 ralign = BYTES_PER_WORD;
 2382 
 2383         if (flags & SLAB_RED_ZONE) {
 2384                 ralign = REDZONE_ALIGN;
 2385                 /* If redzoning, ensure that the second redzone is suitably
 2386                  * aligned, by adjusting the object size accordingly. */
 2387                 size += REDZONE_ALIGN - 1;
 2388                 size &= ~(REDZONE_ALIGN - 1);
 2389         }
 2390 
 2391         /* 3) caller mandated alignment */
 2392         if (ralign < cachep->align) {
 2393                 ralign = cachep->align;
 2394         }
 2395         /* disable debug if necessary */
 2396         if (ralign > __alignof__(unsigned long long))
 2397                 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
 2398         /*
 2399          * 4) Store it.
 2400          */
 2401         cachep->align = ralign;
 2402 
 2403         if (slab_is_available())
 2404                 gfp = GFP_KERNEL;
 2405         else
 2406                 gfp = GFP_NOWAIT;
 2407 
 2408         setup_nodelists_pointer(cachep);
 2409 #if DEBUG
 2410 
 2411         /*
 2412          * Both debugging options require word-alignment which is calculated
 2413          * into align above.
 2414          */
 2415         if (flags & SLAB_RED_ZONE) {
 2416                 /* add space for red zone words */
 2417                 cachep->obj_offset += sizeof(unsigned long long);
 2418                 size += 2 * sizeof(unsigned long long);
 2419         }
 2420         if (flags & SLAB_STORE_USER) {
 2421                 /* user store requires one word storage behind the end of
 2422                  * the real object. But if the second red zone needs to be
 2423                  * aligned to 64 bits, we must allow that much space.
 2424                  */
 2425                 if (flags & SLAB_RED_ZONE)
 2426                         size += REDZONE_ALIGN;
 2427                 else
 2428                         size += BYTES_PER_WORD;
 2429         }
 2430 #if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
 2431         if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
 2432             && cachep->object_size > cache_line_size()
 2433             && ALIGN(size, cachep->align) < PAGE_SIZE) {
 2434                 cachep->obj_offset += PAGE_SIZE - ALIGN(size, cachep->align);
 2435                 size = PAGE_SIZE;
 2436         }
 2437 #endif
 2438 #endif
 2439 
 2440         /*
 2441          * Determine if the slab management is 'on' or 'off' slab.
 2442          * (bootstrapping cannot cope with offslab caches so don't do
 2443          * it too early on. Always use on-slab management when
 2444          * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
 2445          */
 2446         if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init &&
 2447             !(flags & SLAB_NOLEAKTRACE))
 2448                 /*
 2449                  * Size is large, assume best to place the slab management obj
 2450                  * off-slab (should allow better packing of objs).
 2451                  */
 2452                 flags |= CFLGS_OFF_SLAB;
 2453 
 2454         size = ALIGN(size, cachep->align);
 2455 
 2456         left_over = calculate_slab_order(cachep, size, cachep->align, flags);
 2457 
 2458         if (!cachep->num)
 2459                 return -E2BIG;
 2460 
 2461         slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t)
 2462                           + sizeof(struct slab), cachep->align);
 2463 
 2464         /*
 2465          * If the slab has been placed off-slab, and we have enough space then
 2466          * move it on-slab. This is at the expense of any extra colouring.
 2467          */
 2468         if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
 2469                 flags &= ~CFLGS_OFF_SLAB;
 2470                 left_over -= slab_size;
 2471         }
 2472 
 2473         if (flags & CFLGS_OFF_SLAB) {
 2474                 /* really off slab. No need for manual alignment */
 2475                 slab_size =
 2476                     cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab);
 2477 
 2478 #ifdef CONFIG_PAGE_POISONING
 2479                 /* If we're going to use the generic kernel_map_pages()
 2480                  * poisoning, then it's going to smash the contents of
 2481                  * the redzone and userword anyhow, so switch them off.
 2482                  */
 2483                 if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
 2484                         flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
 2485 #endif
 2486         }
 2487 
 2488         cachep->colour_off = cache_line_size();
 2489         /* Offset must be a multiple of the alignment. */
 2490         if (cachep->colour_off < cachep->align)
 2491                 cachep->colour_off = cachep->align;
 2492         cachep->colour = left_over / cachep->colour_off;
 2493         cachep->slab_size = slab_size;
 2494         cachep->flags = flags;
 2495         cachep->allocflags = 0;
 2496         if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
 2497                 cachep->allocflags |= GFP_DMA;
 2498         cachep->size = size;
 2499         cachep->reciprocal_buffer_size = reciprocal_value(size);
 2500 
 2501         if (flags & CFLGS_OFF_SLAB) {
 2502                 cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
 2503                 /*
 2504                  * This is a possibility for one of the malloc_sizes caches.
 2505                  * But since we go off slab only for object size greater than
 2506                  * PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
 2507                  * this should not happen at all.
 2508                  * But leave a BUG_ON for some lucky dude.
 2509                  */
 2510                 BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
 2511         }
 2512 
 2513         err = setup_cpu_cache(cachep, gfp);
 2514         if (err) {
 2515                 __kmem_cache_shutdown(cachep);
 2516                 return err;
 2517         }
 2518 
 2519         if (flags & SLAB_DEBUG_OBJECTS) {
 2520                 /*
 2521                  * Would deadlock through slab_destroy()->call_rcu()->
 2522                  * debug_object_activate()->kmem_cache_alloc().
 2523                  */
 2524                 WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
 2525 
 2526                 slab_set_debugobj_lock_classes(cachep);
 2527         } else if (!OFF_SLAB(cachep) && !(flags & SLAB_DESTROY_BY_RCU))
 2528                 on_slab_lock_classes(cachep);
 2529 
 2530         return 0;
 2531 }
 2532 
 2533 #if DEBUG
 2534 static void check_irq_off(void)
 2535 {
 2536         BUG_ON(!irqs_disabled());
 2537 }
 2538 
 2539 static void check_irq_on(void)
 2540 {
 2541         BUG_ON(irqs_disabled());
 2542 }
 2543 
 2544 static void check_spinlock_acquired(struct kmem_cache *cachep)
 2545 {
 2546 #ifdef CONFIG_SMP
 2547         check_irq_off();
 2548         assert_spin_locked(&cachep->nodelists[numa_mem_id()]->list_lock);
 2549 #endif
 2550 }
 2551 
 2552 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
 2553 {
 2554 #ifdef CONFIG_SMP
 2555         check_irq_off();
 2556         assert_spin_locked(&cachep->nodelists[node]->list_lock);
 2557 #endif
 2558 }
 2559 
 2560 #else
 2561 #define check_irq_off() do { } while(0)
 2562 #define check_irq_on()  do { } while(0)
 2563 #define check_spinlock_acquired(x) do { } while(0)
 2564 #define check_spinlock_acquired_node(x, y) do { } while(0)
 2565 #endif
 2566 
 2567 static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
 2568                         struct array_cache *ac,
 2569                         int force, int node);
 2570 
 2571 static void do_drain(void *arg)
 2572 {
 2573         struct kmem_cache *cachep = arg;
 2574         struct array_cache *ac;
 2575         int node = numa_mem_id();
 2576 
 2577         check_irq_off();
 2578         ac = cpu_cache_get(cachep);
 2579         spin_lock(&cachep->nodelists[node]->list_lock);
 2580         free_block(cachep, ac->entry, ac->avail, node);
 2581         spin_unlock(&cachep->nodelists[node]->list_lock);
 2582         ac->avail = 0;
 2583 }
 2584 
 2585 static void drain_cpu_caches(struct kmem_cache *cachep)
 2586 {
 2587         struct kmem_list3 *l3;
 2588         int node;
 2589 
 2590         on_each_cpu(do_drain, cachep, 1);
 2591         check_irq_on();
 2592         for_each_online_node(node) {
 2593                 l3 = cachep->nodelists[node];
 2594                 if (l3 && l3->alien)
 2595                         drain_alien_cache(cachep, l3->alien);
 2596         }
 2597 
 2598         for_each_online_node(node) {
 2599                 l3 = cachep->nodelists[node];
 2600                 if (l3)
 2601                         drain_array(cachep, l3, l3->shared, 1, node);
 2602         }
 2603 }
 2604 
 2605 /*
 2606  * Remove slabs from the list of free slabs.
 2607  * Specify the number of slabs to drain in tofree.
 2608  *
 2609  * Returns the actual number of slabs released.
 2610  */
 2611 static int drain_freelist(struct kmem_cache *cache,
 2612                         struct kmem_list3 *l3, int tofree)
 2613 {
 2614         struct list_head *p;
 2615         int nr_freed;
 2616         struct slab *slabp;
 2617 
 2618         nr_freed = 0;
 2619         while (nr_freed < tofree && !list_empty(&l3->slabs_free)) {
 2620 
 2621                 spin_lock_irq(&l3->list_lock);
 2622                 p = l3->slabs_free.prev;
 2623                 if (p == &l3->slabs_free) {
 2624                         spin_unlock_irq(&l3->list_lock);
 2625                         goto out;
 2626                 }
 2627 
 2628                 slabp = list_entry(p, struct slab, list);
 2629 #if DEBUG
 2630                 BUG_ON(slabp->inuse);
 2631 #endif
 2632                 list_del(&slabp->list);
 2633                 /*
 2634                  * Safe to drop the lock. The slab is no longer linked
 2635                  * to the cache.
 2636                  */
 2637                 l3->free_objects -= cache->num;
 2638                 spin_unlock_irq(&l3->list_lock);
 2639                 slab_destroy(cache, slabp);
 2640                 nr_freed++;
 2641         }
 2642 out:
 2643         return nr_freed;
 2644 }
 2645 
 2646 /* Called with slab_mutex held to protect against cpu hotplug */
 2647 static int __cache_shrink(struct kmem_cache *cachep)
 2648 {
 2649         int ret = 0, i = 0;
 2650         struct kmem_list3 *l3;
 2651 
 2652         drain_cpu_caches(cachep);
 2653 
 2654         check_irq_on();
 2655         for_each_online_node(i) {
 2656                 l3 = cachep->nodelists[i];
 2657                 if (!l3)
 2658                         continue;
 2659 
 2660                 drain_freelist(cachep, l3, l3->free_objects);
 2661 
 2662                 ret += !list_empty(&l3->slabs_full) ||
 2663                         !list_empty(&l3->slabs_partial);
 2664         }
 2665         return (ret ? 1 : 0);
 2666 }
 2667 
 2668 /**
 2669  * kmem_cache_shrink - Shrink a cache.
 2670  * @cachep: The cache to shrink.
 2671  *
 2672  * Releases as many slabs as possible for a cache.
 2673  * To help debugging, a zero exit status indicates all slabs were released.
 2674  */
 2675 int kmem_cache_shrink(struct kmem_cache *cachep)
 2676 {
 2677         int ret;
 2678         BUG_ON(!cachep || in_interrupt());
 2679 
 2680         get_online_cpus();
 2681         mutex_lock(&slab_mutex);
 2682         ret = __cache_shrink(cachep);
 2683         mutex_unlock(&slab_mutex);
 2684         put_online_cpus();
 2685         return ret;
 2686 }
 2687 EXPORT_SYMBOL(kmem_cache_shrink);
 2688 
 2689 int __kmem_cache_shutdown(struct kmem_cache *cachep)
 2690 {
 2691         int i;
 2692         struct kmem_list3 *l3;
 2693         int rc = __cache_shrink(cachep);
 2694 
 2695         if (rc)
 2696                 return rc;
 2697 
 2698         for_each_online_cpu(i)
 2699             kfree(cachep->array[i]);
 2700 
 2701         /* NUMA: free the list3 structures */
 2702         for_each_online_node(i) {
 2703                 l3 = cachep->nodelists[i];
 2704                 if (l3) {
 2705                         kfree(l3->shared);
 2706                         free_alien_cache(l3->alien);
 2707                         kfree(l3);
 2708                 }
 2709         }
 2710         return 0;
 2711 }
 2712 
 2713 /*
 2714  * Get the memory for a slab management obj.
 2715  * For a slab cache when the slab descriptor is off-slab, slab descriptors
 2716  * always come from malloc_sizes caches.  The slab descriptor cannot
 2717  * come from the same cache which is getting created because,
 2718  * when we are searching for an appropriate cache for these
 2719  * descriptors in kmem_cache_create, we search through the malloc_sizes array.
 2720  * If we are creating a malloc_sizes cache here it would not be visible to
 2721  * kmem_find_general_cachep till the initialization is complete.
 2722  * Hence we cannot have slabp_cache same as the original cache.
 2723  */
 2724 static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,
 2725                                    int colour_off, gfp_t local_flags,
 2726                                    int nodeid)
 2727 {
 2728         struct slab *slabp;
 2729 
 2730         if (OFF_SLAB(cachep)) {
 2731                 /* Slab management obj is off-slab. */
 2732                 slabp = kmem_cache_alloc_node(cachep->slabp_cache,
 2733                                               local_flags, nodeid);
 2734                 /*
 2735                  * If the first object in the slab is leaked (it's allocated
 2736                  * but no one has a reference to it), we want to make sure
 2737                  * kmemleak does not treat the ->s_mem pointer as a reference
 2738                  * to the object. Otherwise we will not report the leak.
 2739                  */
 2740                 kmemleak_scan_area(&slabp->list, sizeof(struct list_head),
 2741                                    local_flags);
 2742                 if (!slabp)
 2743                         return NULL;
 2744         } else {
 2745                 slabp = objp + colour_off;
 2746                 colour_off += cachep->slab_size;
 2747         }
 2748         slabp->inuse = 0;
 2749         slabp->colouroff = colour_off;
 2750         slabp->s_mem = objp + colour_off;
 2751         slabp->nodeid = nodeid;
 2752         slabp->free = 0;
 2753         return slabp;
 2754 }
 2755 
 2756 static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
 2757 {
 2758         return (kmem_bufctl_t *) (slabp + 1);
 2759 }
 2760 
 2761 static void cache_init_objs(struct kmem_cache *cachep,
 2762                             struct slab *slabp)
 2763 {
 2764         int i;
 2765 
 2766         for (i = 0; i < cachep->num; i++) {
 2767                 void *objp = index_to_obj(cachep, slabp, i);
 2768 #if DEBUG
 2769                 /* need to poison the objs? */
 2770                 if (cachep->flags & SLAB_POISON)
 2771                         poison_obj(cachep, objp, POISON_FREE);
 2772                 if (cachep->flags & SLAB_STORE_USER)
 2773                         *dbg_userword(cachep, objp) = NULL;
 2774 
 2775                 if (cachep->flags & SLAB_RED_ZONE) {
 2776                         *dbg_redzone1(cachep, objp) = RED_INACTIVE;
 2777                         *dbg_redzone2(cachep, objp) = RED_INACTIVE;
 2778                 }
 2779                 /*
 2780                  * Constructors are not allowed to allocate memory from the same
 2781                  * cache which they are a constructor for.  Otherwise, deadlock.
 2782                  * They must also be threaded.
 2783                  */
 2784                 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
 2785                         cachep->ctor(objp + obj_offset(cachep));
 2786 
 2787                 if (cachep->flags & SLAB_RED_ZONE) {
 2788                         if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
 2789                                 slab_error(cachep, "constructor overwrote the"
 2790                                            " end of an object");
 2791                         if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
 2792                                 slab_error(cachep, "constructor overwrote the"
 2793                                            " start of an object");
 2794                 }
 2795                 if ((cachep->size % PAGE_SIZE) == 0 &&
 2796                             OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
 2797                         kernel_map_pages(virt_to_page(objp),
 2798                                          cachep->size / PAGE_SIZE, 0);
 2799 #else
 2800                 if (cachep->ctor)
 2801                         cachep->ctor(objp);
 2802 #endif
 2803                 slab_bufctl(slabp)[i] = i + 1;
 2804         }
 2805         slab_bufctl(slabp)[i - 1] = BUFCTL_END;
 2806 }
 2807 
 2808 static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
 2809 {
 2810         if (CONFIG_ZONE_DMA_FLAG) {
 2811                 if (flags & GFP_DMA)
 2812                         BUG_ON(!(cachep->allocflags & GFP_DMA));
 2813                 else
 2814                         BUG_ON(cachep->allocflags & GFP_DMA);
 2815         }
 2816 }
 2817 
 2818 static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
 2819                                 int nodeid)
 2820 {
 2821         void *objp = index_to_obj(cachep, slabp, slabp->free);
 2822         kmem_bufctl_t next;
 2823 
 2824         slabp->inuse++;
 2825         next = slab_bufctl(slabp)[slabp->free];
 2826 #if DEBUG
 2827         slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
 2828         WARN_ON(slabp->nodeid != nodeid);
 2829 #endif
 2830         slabp->free = next;
 2831 
 2832         return objp;
 2833 }
 2834 
 2835 static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
 2836                                 void *objp, int nodeid)
 2837 {
 2838         unsigned int objnr = obj_to_index(cachep, slabp, objp);
 2839 
 2840 #if DEBUG
 2841         /* Verify that the slab belongs to the intended node */
 2842         WARN_ON(slabp->nodeid != nodeid);
 2843 
 2844         if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
 2845                 printk(KERN_ERR "slab: double free detected in cache "
 2846                                 "'%s', objp %p\n", cachep->name, objp);
 2847                 BUG();
 2848         }
 2849 #endif
 2850         slab_bufctl(slabp)[objnr] = slabp->free;
 2851         slabp->free = objnr;
 2852         slabp->inuse--;
 2853 }
 2854 
 2855 /*
 2856  * Map pages beginning at addr to the given cache and slab. This is required
 2857  * for the slab allocator to be able to lookup the cache and slab of a
 2858  * virtual address for kfree, ksize, and slab debugging.
 2859  */
 2860 static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
 2861                            void *addr)
 2862 {
 2863         int nr_pages;
 2864         struct page *page;
 2865 
 2866         page = virt_to_page(addr);
 2867 
 2868         nr_pages = 1;
 2869         if (likely(!PageCompound(page)))
 2870                 nr_pages <<= cache->gfporder;
 2871 
 2872         do {
 2873                 page->slab_cache = cache;
 2874                 page->slab_page = slab;
 2875                 page++;
 2876         } while (--nr_pages);
 2877 }
 2878 
 2879 /*
 2880  * Grow (by 1) the number of slabs within a cache.  This is called by
 2881  * kmem_cache_alloc() when there are no active objs left in a cache.
 2882  */
 2883 static int cache_grow(struct kmem_cache *cachep,
 2884                 gfp_t flags, int nodeid, void *objp)
 2885 {
 2886         struct slab *slabp;
 2887         size_t offset;
 2888         gfp_t local_flags;
 2889         struct kmem_list3 *l3;
 2890 
 2891         /*
 2892          * Be lazy and only check for valid flags here,  keeping it out of the
 2893          * critical path in kmem_cache_alloc().
 2894          */
 2895         BUG_ON(flags & GFP_SLAB_BUG_MASK);
 2896         local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
 2897 
 2898         /* Take the l3 list lock to change the colour_next on this node */
 2899         check_irq_off();
 2900         l3 = cachep->nodelists[nodeid];
 2901         spin_lock(&l3->list_lock);
 2902 
 2903         /* Get colour for the slab, and cal the next value. */
 2904         offset = l3->colour_next;
 2905         l3->colour_next++;
 2906         if (l3->colour_next >= cachep->colour)
 2907                 l3->colour_next = 0;
 2908         spin_unlock(&l3->list_lock);
 2909 
 2910         offset *= cachep->colour_off;
 2911 
 2912         if (local_flags & __GFP_WAIT)
 2913                 local_irq_enable();
 2914 
 2915         /*
 2916          * The test for missing atomic flag is performed here, rather than
 2917          * the more obvious place, simply to reduce the critical path length
 2918          * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
 2919          * will eventually be caught here (where it matters).
 2920          */
 2921         kmem_flagcheck(cachep, flags);
 2922 
 2923         /*
 2924          * Get mem for the objs.  Attempt to allocate a physical page from
 2925          * 'nodeid'.
 2926          */
 2927         if (!objp)
 2928                 objp = kmem_getpages(cachep, local_flags, nodeid);
 2929         if (!objp)
 2930                 goto failed;
 2931 
 2932         /* Get slab management. */
 2933         slabp = alloc_slabmgmt(cachep, objp, offset,
 2934                         local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
 2935         if (!slabp)
 2936                 goto opps1;
 2937 
 2938         slab_map_pages(cachep, slabp, objp);
 2939 
 2940         cache_init_objs(cachep, slabp);
 2941 
 2942         if (local_flags & __GFP_WAIT)
 2943                 local_irq_disable();
 2944         check_irq_off();
 2945         spin_lock(&l3->list_lock);
 2946 
 2947         /* Make slab active. */
 2948         list_add_tail(&slabp->list, &(l3->slabs_free));
 2949         STATS_INC_GROWN(cachep);
 2950         l3->free_objects += cachep->num;
 2951         spin_unlock(&l3->list_lock);
 2952         return 1;
 2953 opps1:
 2954         kmem_freepages(cachep, objp);
 2955 failed:
 2956         if (local_flags & __GFP_WAIT)
 2957                 local_irq_disable();
 2958         return 0;
 2959 }
 2960 
 2961 #if DEBUG
 2962 
 2963 /*
 2964  * Perform extra freeing checks:
 2965  * - detect bad pointers.
 2966  * - POISON/RED_ZONE checking
 2967  */
 2968 static void kfree_debugcheck(const void *objp)
 2969 {
 2970         if (!virt_addr_valid(objp)) {
 2971                 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
 2972                        (unsigned long)objp);
 2973                 BUG();
 2974         }
 2975 }
 2976 
 2977 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
 2978 {
 2979         unsigned long long redzone1, redzone2;
 2980 
 2981         redzone1 = *dbg_redzone1(cache, obj);
 2982         redzone2 = *dbg_redzone2(cache, obj);
 2983 
 2984         /*
 2985          * Redzone is ok.
 2986          */
 2987         if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
 2988                 return;
 2989 
 2990         if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
 2991                 slab_error(cache, "double free detected");
 2992         else
 2993                 slab_error(cache, "memory outside object was overwritten");
 2994 
 2995         printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
 2996                         obj, redzone1, redzone2);
 2997 }
 2998 
 2999 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
 3000                                    unsigned long caller)
 3001 {
 3002         struct page *page;
 3003         unsigned int objnr;
 3004         struct slab *slabp;
 3005 
 3006         BUG_ON(virt_to_cache(objp) != cachep);
 3007 
 3008         objp -= obj_offset(cachep);
 3009         kfree_debugcheck(objp);
 3010         page = virt_to_head_page(objp);
 3011 
 3012         slabp = page->slab_page;
 3013 
 3014         if (cachep->flags & SLAB_RED_ZONE) {
 3015                 verify_redzone_free(cachep, objp);
 3016                 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
 3017                 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
 3018         }
 3019         if (cachep->flags & SLAB_STORE_USER)
 3020                 *dbg_userword(cachep, objp) = (void *)caller;
 3021 
 3022         objnr = obj_to_index(cachep, slabp, objp);
 3023 
 3024         BUG_ON(objnr >= cachep->num);
 3025         BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
 3026 
 3027 #ifdef CONFIG_DEBUG_SLAB_LEAK
 3028         slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
 3029 #endif
 3030         if (cachep->flags & SLAB_POISON) {
 3031 #ifdef CONFIG_DEBUG_PAGEALLOC
 3032                 if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
 3033                         store_stackinfo(cachep, objp, caller);
 3034                         kernel_map_pages(virt_to_page(objp),
 3035                                          cachep->size / PAGE_SIZE, 0);
 3036                 } else {
 3037                         poison_obj(cachep, objp, POISON_FREE);
 3038                 }
 3039 #else
 3040                 poison_obj(cachep, objp, POISON_FREE);
 3041 #endif
 3042         }
 3043         return objp;
 3044 }
 3045 
 3046 static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
 3047 {
 3048         kmem_bufctl_t i;
 3049         int entries = 0;
 3050 
 3051         /* Check slab's freelist to see if this obj is there. */
 3052         for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
 3053                 entries++;
 3054                 if (entries > cachep->num || i >= cachep->num)
 3055                         goto bad;
 3056         }
 3057         if (entries != cachep->num - slabp->inuse) {
 3058 bad:
 3059                 printk(KERN_ERR "slab: Internal list corruption detected in "
 3060                         "cache '%s'(%d), slabp %p(%d). Tainted(%s). Hexdump:\n",
 3061                         cachep->name, cachep->num, slabp, slabp->inuse,
 3062                         print_tainted());
 3063                 print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp,
 3064                         sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t),
 3065                         1);
 3066                 BUG();
 3067         }
 3068 }
 3069 #else
 3070 #define kfree_debugcheck(x) do { } while(0)
 3071 #define cache_free_debugcheck(x,objp,z) (objp)
 3072 #define check_slabp(x,y) do { } while(0)
 3073 #endif
 3074 
 3075 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags,
 3076                                                         bool force_refill)
 3077 {
 3078         int batchcount;
 3079         struct kmem_list3 *l3;
 3080         struct array_cache *ac;
 3081         int node;
 3082 
 3083         check_irq_off();
 3084         node = numa_mem_id();
 3085         if (unlikely(force_refill))
 3086                 goto force_grow;
 3087 retry:
 3088         ac = cpu_cache_get(cachep);
 3089         batchcount = ac->batchcount;
 3090         if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
 3091                 /*
 3092                  * If there was little recent activity on this cache, then
 3093                  * perform only a partial refill.  Otherwise we could generate
 3094                  * refill bouncing.
 3095                  */
 3096                 batchcount = BATCHREFILL_LIMIT;
 3097         }
 3098         l3 = cachep->nodelists[node];
 3099 
 3100         BUG_ON(ac->avail > 0 || !l3);
 3101         spin_lock(&l3->list_lock);
 3102 
 3103         /* See if we can refill from the shared array */
 3104         if (l3->shared && transfer_objects(ac, l3->shared, batchcount)) {
 3105                 l3->shared->touched = 1;
 3106                 goto alloc_done;
 3107         }
 3108 
 3109         while (batchcount > 0) {
 3110                 struct list_head *entry;
 3111                 struct slab *slabp;
 3112                 /* Get slab alloc is to come from. */
 3113                 entry = l3->slabs_partial.next;
 3114                 if (entry == &l3->slabs_partial) {
 3115                         l3->free_touched = 1;
 3116                         entry = l3->slabs_free.next;
 3117                         if (entry == &l3->slabs_free)
 3118                                 goto must_grow;
 3119                 }
 3120 
 3121                 slabp = list_entry(entry, struct slab, list);
 3122                 check_slabp(cachep, slabp);
 3123                 check_spinlock_acquired(cachep);
 3124 
 3125                 /*
 3126                  * The slab was either on partial or free list so
 3127                  * there must be at least one object available for
 3128                  * allocation.
 3129                  */
 3130                 BUG_ON(slabp->inuse >= cachep->num);
 3131 
 3132                 while (slabp->inuse < cachep->num && batchcount--) {
 3133                         STATS_INC_ALLOCED(cachep);
 3134                         STATS_INC_ACTIVE(cachep);
 3135                         STATS_SET_HIGH(cachep);
 3136 
 3137                         ac_put_obj(cachep, ac, slab_get_obj(cachep, slabp,
 3138                                                                         node));
 3139                 }
 3140                 check_slabp(cachep, slabp);
 3141 
 3142                 /* move slabp to correct slabp list: */
 3143                 list_del(&slabp->list);
 3144                 if (slabp->free == BUFCTL_END)
 3145                         list_add(&slabp->list, &l3->slabs_full);
 3146                 else
 3147                         list_add(&slabp->list, &l3->slabs_partial);
 3148         }
 3149 
 3150 must_grow:
 3151         l3->free_objects -= ac->avail;
 3152 alloc_done:
 3153         spin_unlock(&l3->list_lock);
 3154 
 3155         if (unlikely(!ac->avail)) {
 3156                 int x;
 3157 force_grow:
 3158                 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
 3159 
 3160                 /* cache_grow can reenable interrupts, then ac could change. */
 3161                 ac = cpu_cache_get(cachep);
 3162                 node = numa_mem_id();
 3163 
 3164                 /* no objects in sight? abort */
 3165                 if (!x && (ac->avail == 0 || force_refill))
 3166                         return NULL;
 3167 
 3168                 if (!ac->avail)         /* objects refilled by interrupt? */
 3169                         goto retry;
 3170         }
 3171         ac->touched = 1;
 3172 
 3173         return ac_get_obj(cachep, ac, flags, force_refill);
 3174 }
 3175 
 3176 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
 3177                                                 gfp_t flags)
 3178 {
 3179         might_sleep_if(flags & __GFP_WAIT);
 3180 #if DEBUG
 3181         kmem_flagcheck(cachep, flags);
 3182 #endif
 3183 }
 3184 
 3185 #if DEBUG
 3186 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
 3187                                 gfp_t flags, void *objp, unsigned long caller)
 3188 {
 3189         if (!objp)
 3190                 return objp;
 3191         if (cachep->flags & SLAB_POISON) {
 3192 #ifdef CONFIG_DEBUG_PAGEALLOC
 3193                 if ((cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
 3194                         kernel_map_pages(virt_to_page(objp),
 3195                                          cachep->size / PAGE_SIZE, 1);
 3196                 else
 3197                         check_poison_obj(cachep, objp);
 3198 #else
 3199                 check_poison_obj(cachep, objp);
 3200 #endif
 3201                 poison_obj(cachep, objp, POISON_INUSE);
 3202         }
 3203         if (cachep->flags & SLAB_STORE_USER)
 3204                 *dbg_userword(cachep, objp) = (void *)caller;
 3205 
 3206         if (cachep->flags & SLAB_RED_ZONE) {
 3207                 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
 3208                                 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
 3209                         slab_error(cachep, "double free, or memory outside"
 3210                                                 " object was overwritten");
 3211                         printk(KERN_ERR
 3212                                 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n",
 3213                                 objp, *dbg_redzone1(cachep, objp),
 3214                                 *dbg_redzone2(cachep, objp));
 3215                 }
 3216                 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
 3217                 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
 3218         }
 3219 #ifdef CONFIG_DEBUG_SLAB_LEAK
 3220         {
 3221                 struct slab *slabp;
 3222                 unsigned objnr;
 3223 
 3224                 slabp = virt_to_head_page(objp)->slab_page;
 3225                 objnr = (unsigned)(objp - slabp->s_mem) / cachep->size;
 3226                 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
 3227         }
 3228 #endif
 3229         objp += obj_offset(cachep);
 3230         if (cachep->ctor && cachep->flags & SLAB_POISON)
 3231                 cachep->ctor(objp);
 3232         if (ARCH_SLAB_MINALIGN &&
 3233             ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
 3234                 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
 3235                        objp, (int)ARCH_SLAB_MINALIGN);
 3236         }
 3237         return objp;
 3238 }
 3239 #else
 3240 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
 3241 #endif
 3242 
 3243 static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
 3244 {
 3245         if (cachep == kmem_cache)
 3246                 return false;
 3247 
 3248         return should_failslab(cachep->object_size, flags, cachep->flags);
 3249 }
 3250 
 3251 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 3252 {
 3253         void *objp;
 3254         struct array_cache *ac;
 3255         bool force_refill = false;
 3256 
 3257         check_irq_off();
 3258 
 3259         ac = cpu_cache_get(cachep);
 3260         if (likely(ac->avail)) {
 3261                 ac->touched = 1;
 3262                 objp = ac_get_obj(cachep, ac, flags, false);
 3263 
 3264                 /*
 3265                  * Allow for the possibility all avail objects are not allowed
 3266                  * by the current flags
 3267                  */
 3268                 if (objp) {
 3269                         STATS_INC_ALLOCHIT(cachep);
 3270                         goto out;
 3271                 }
 3272                 force_refill = true;
 3273         }
 3274 
 3275         STATS_INC_ALLOCMISS(cachep);
 3276         objp = cache_alloc_refill(cachep, flags, force_refill);
 3277         /*
 3278          * the 'ac' may be updated by cache_alloc_refill(),
 3279          * and kmemleak_erase() requires its correct value.
 3280          */
 3281         ac = cpu_cache_get(cachep);
 3282 
 3283 out:
 3284         /*
 3285          * To avoid a false negative, if an object that is in one of the
 3286          * per-CPU caches is leaked, we need to make sure kmemleak doesn't
 3287          * treat the array pointers as a reference to the object.
 3288          */
 3289         if (objp)
 3290                 kmemleak_erase(&ac->entry[ac->avail]);
 3291         return objp;
 3292 }
 3293 
 3294 #ifdef CONFIG_NUMA
 3295 /*
 3296  * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
 3297  *
 3298  * If we are in_interrupt, then process context, including cpusets and
 3299  * mempolicy, may not apply and should not be used for allocation policy.
 3300  */
 3301 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
 3302 {
 3303         int nid_alloc, nid_here;
 3304 
 3305         if (in_interrupt() || (flags & __GFP_THISNODE))
 3306                 return NULL;
 3307         nid_alloc = nid_here = numa_mem_id();
 3308         if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
 3309                 nid_alloc = cpuset_slab_spread_node();
 3310         else if (current->mempolicy)
 3311                 nid_alloc = slab_node();
 3312         if (nid_alloc != nid_here)
 3313                 return ____cache_alloc_node(cachep, flags, nid_alloc);
 3314         return NULL;
 3315 }
 3316 
 3317 /*
 3318  * Fallback function if there was no memory available and no objects on a
 3319  * certain node and fall back is permitted. First we scan all the
 3320  * available nodelists for available objects. If that fails then we
 3321  * perform an allocation without specifying a node. This allows the page
 3322  * allocator to do its reclaim / fallback magic. We then insert the
 3323  * slab into the proper nodelist and then allocate from it.
 3324  */
 3325 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
 3326 {
 3327         struct zonelist *zonelist;
 3328         gfp_t local_flags;
 3329         struct zoneref *z;
 3330         struct zone *zone;
 3331         enum zone_type high_zoneidx = gfp_zone(flags);
 3332         void *obj = NULL;
 3333         int nid;
 3334         unsigned int cpuset_mems_cookie;
 3335 
 3336         if (flags & __GFP_THISNODE)
 3337                 return NULL;
 3338 
 3339         local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
 3340 
 3341 retry_cpuset:
 3342         cpuset_mems_cookie = get_mems_allowed();
 3343         zonelist = node_zonelist(slab_node(), flags);
 3344 
 3345 retry:
 3346         /*
 3347          * Look through allowed nodes for objects available
 3348          * from existing per node queues.
 3349          */
 3350         for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
 3351                 nid = zone_to_nid(zone);
 3352 
 3353                 if (cpuset_zone_allowed_hardwall(zone, flags) &&
 3354                         cache->nodelists[nid] &&
 3355                         cache->nodelists[nid]->free_objects) {
 3356                                 obj = ____cache_alloc_node(cache,
 3357                                         flags | GFP_THISNODE, nid);
 3358                                 if (obj)
 3359                                         break;
 3360                 }
 3361         }
 3362 
 3363         if (!obj) {
 3364                 /*
 3365                  * This allocation will be performed within the constraints
 3366                  * of the current cpuset / memory policy requirements.
 3367                  * We may trigger various forms of reclaim on the allowed
 3368                  * set and go into memory reserves if necessary.
 3369                  */
 3370                 if (local_flags & __GFP_WAIT)
 3371                         local_irq_enable();
 3372                 kmem_flagcheck(cache, flags);
 3373                 obj = kmem_getpages(cache, local_flags, numa_mem_id());
 3374                 if (local_flags & __GFP_WAIT)
 3375                         local_irq_disable();
 3376                 if (obj) {
 3377                         /*
 3378                          * Insert into the appropriate per node queues
 3379                          */
 3380                         nid = page_to_nid(virt_to_page(obj));
 3381                         if (cache_grow(cache, flags, nid, obj)) {
 3382                                 obj = ____cache_alloc_node(cache,
 3383                                         flags | GFP_THISNODE, nid);
 3384                                 if (!obj)
 3385                                         /*
 3386                                          * Another processor may allocate the
 3387                                          * objects in the slab since we are
 3388                                          * not holding any locks.
 3389                                          */
 3390                                         goto retry;
 3391                         } else {
 3392                                 /* cache_grow already freed obj */
 3393                                 obj = NULL;
 3394                         }
 3395                 }
 3396         }
 3397 
 3398         if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !obj))
 3399                 goto retry_cpuset;
 3400         return obj;
 3401 }
 3402 
 3403 /*
 3404  * A interface to enable slab creation on nodeid
 3405  */
 3406 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
 3407                                 int nodeid)
 3408 {
 3409         struct list_head *entry;
 3410         struct slab *slabp;
 3411         struct kmem_list3 *l3;
 3412         void *obj;
 3413         int x;
 3414 
 3415         l3 = cachep->nodelists[nodeid];
 3416         BUG_ON(!l3);
 3417 
 3418 retry:
 3419         check_irq_off();
 3420         spin_lock(&l3->list_lock);
 3421         entry = l3->slabs_partial.next;
 3422         if (entry == &l3->slabs_partial) {
 3423                 l3->free_touched = 1;
 3424                 entry = l3->slabs_free.next;
 3425                 if (entry == &l3->slabs_free)
 3426                         goto must_grow;
 3427         }
 3428 
 3429         slabp = list_entry(entry, struct slab, list);
 3430         check_spinlock_acquired_node(cachep, nodeid);
 3431         check_slabp(cachep, slabp);
 3432 
 3433         STATS_INC_NODEALLOCS(cachep);
 3434         STATS_INC_ACTIVE(cachep);
 3435         STATS_SET_HIGH(cachep);
 3436 
 3437         BUG_ON(slabp->inuse == cachep->num);
 3438 
 3439         obj = slab_get_obj(cachep, slabp, nodeid);
 3440         check_slabp(cachep, slabp);
 3441         l3->free_objects--;
 3442         /* move slabp to correct slabp list: */
 3443         list_del(&slabp->list);
 3444 
 3445         if (slabp->free == BUFCTL_END)
 3446                 list_add(&slabp->list, &l3->slabs_full);
 3447         else
 3448                 list_add(&slabp->list, &l3->slabs_partial);
 3449 
 3450         spin_unlock(&l3->list_lock);
 3451         goto done;
 3452 
 3453 must_grow:
 3454         spin_unlock(&l3->list_lock);
 3455         x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
 3456         if (x)
 3457                 goto retry;
 3458 
 3459         return fallback_alloc(cachep, flags);
 3460 
 3461 done:
 3462         return obj;
 3463 }
 3464 
 3465 /**
 3466  * kmem_cache_alloc_node - Allocate an object on the specified node
 3467  * @cachep: The cache to allocate from.
 3468  * @flags: See kmalloc().
 3469  * @nodeid: node number of the target node.
 3470  * @caller: return address of caller, used for debug information
 3471  *
 3472  * Identical to kmem_cache_alloc but it will allocate memory on the given
 3473  * node, which can improve the performance for cpu bound structures.
 3474  *
 3475  * Fallback to other node is possible if __GFP_THISNODE is not set.
 3476  */
 3477 static __always_inline void *
 3478 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
 3479                    unsigned long caller)
 3480 {
 3481         unsigned long save_flags;
 3482         void *ptr;
 3483         int slab_node = numa_mem_id();
 3484 
 3485         flags &= gfp_allowed_mask;
 3486 
 3487         lockdep_trace_alloc(flags);
 3488 
 3489         if (slab_should_failslab(cachep, flags))
 3490                 return NULL;
 3491 
 3492         cachep = memcg_kmem_get_cache(cachep, flags);
 3493 
 3494         cache_alloc_debugcheck_before(cachep, flags);
 3495         local_irq_save(save_flags);
 3496 
 3497         if (nodeid == NUMA_NO_NODE)
 3498                 nodeid = slab_node;
 3499 
 3500         if (unlikely(!cachep->nodelists[nodeid])) {
 3501                 /* Node not bootstrapped yet */
 3502                 ptr = fallback_alloc(cachep, flags);
 3503                 goto out;
 3504         }
 3505 
 3506         if (nodeid == slab_node) {
 3507                 /*
 3508                  * Use the locally cached objects if possible.
 3509                  * However ____cache_alloc does not allow fallback
 3510                  * to other nodes. It may fail while we still have
 3511                  * objects on other nodes available.
 3512                  */
 3513                 ptr = ____cache_alloc(cachep, flags);
 3514                 if (ptr)
 3515                         goto out;
 3516         }
 3517         /* ___cache_alloc_node can fall back to other nodes */
 3518         ptr = ____cache_alloc_node(cachep, flags, nodeid);
 3519   out:
 3520         local_irq_restore(save_flags);
 3521         ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
 3522         kmemleak_alloc_recursive(ptr, cachep->object_size, 1, cachep->flags,
 3523                                  flags);
 3524 
 3525         if (likely(ptr))
 3526                 kmemcheck_slab_alloc(cachep, flags, ptr, cachep->object_size);
 3527 
 3528         if (unlikely((flags & __GFP_ZERO) && ptr))
 3529                 memset(ptr, 0, cachep->object_size);
 3530 
 3531         return ptr;
 3532 }
 3533 
 3534 static __always_inline void *
 3535 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
 3536 {
 3537         void *objp;
 3538 
 3539         if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
 3540                 objp = alternate_node_alloc(cache, flags);
 3541                 if (objp)
 3542                         goto out;
 3543         }
 3544         objp = ____cache_alloc(cache, flags);
 3545 
 3546         /*
 3547          * We may just have run out of memory on the local node.
 3548          * ____cache_alloc_node() knows how to locate memory on other nodes
 3549          */
 3550         if (!objp)
 3551                 objp = ____cache_alloc_node(cache, flags, numa_mem_id());
 3552 
 3553   out:
 3554         return objp;
 3555 }
 3556 #else
 3557 
 3558 static __always_inline void *
 3559 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 3560 {
 3561         return ____cache_alloc(cachep, flags);
 3562 }
 3563 
 3564 #endif /* CONFIG_NUMA */
 3565 
 3566 static __always_inline void *
 3567 slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller)
 3568 {
 3569         unsigned long save_flags;
 3570         void *objp;
 3571 
 3572         flags &= gfp_allowed_mask;
 3573 
 3574         lockdep_trace_alloc(flags);
 3575 
 3576         if (slab_should_failslab(cachep, flags))
 3577                 return NULL;
 3578 
 3579         cachep = memcg_kmem_get_cache(cachep, flags);
 3580 
 3581         cache_alloc_debugcheck_before(cachep, flags);
 3582         local_irq_save(save_flags);
 3583         objp = __do_cache_alloc(cachep, flags);
 3584         local_irq_restore(save_flags);
 3585         objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
 3586         kmemleak_alloc_recursive(objp, cachep->object_size, 1, cachep->flags,
 3587                                  flags);
 3588         prefetchw(objp);
 3589 
 3590         if (likely(objp))
 3591                 kmemcheck_slab_alloc(cachep, flags, objp, cachep->object_size);
 3592 
 3593         if (unlikely((flags & __GFP_ZERO) && objp))
 3594                 memset(objp, 0, cachep->object_size);
 3595 
 3596         return objp;
 3597 }
 3598 
 3599 /*
 3600  * Caller needs to acquire correct kmem_list's list_lock
 3601  */
 3602 static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
 3603                        int node)
 3604 {
 3605         int i;
 3606         struct kmem_list3 *l3;
 3607 
 3608         for (i = 0; i < nr_objects; i++) {
 3609                 void *objp;
 3610                 struct slab *slabp;
 3611 
 3612                 clear_obj_pfmemalloc(&objpp[i]);
 3613                 objp = objpp[i];
 3614 
 3615                 slabp = virt_to_slab(objp);
 3616                 l3 = cachep->nodelists[node];
 3617                 list_del(&slabp->list);
 3618                 check_spinlock_acquired_node(cachep, node);
 3619                 check_slabp(cachep, slabp);
 3620                 slab_put_obj(cachep, slabp, objp, node);
 3621                 STATS_DEC_ACTIVE(cachep);
 3622                 l3->free_objects++;
 3623                 check_slabp(cachep, slabp);
 3624 
 3625                 /* fixup slab chains */
 3626                 if (slabp->inuse == 0) {
 3627                         if (l3->free_objects > l3->free_limit) {
 3628                                 l3->free_objects -= cachep->num;
 3629                                 /* No need to drop any previously held
 3630                                  * lock here, even if we have a off-slab slab
 3631                                  * descriptor it is guaranteed to come from
 3632                                  * a different cache, refer to comments before
 3633                                  * alloc_slabmgmt.
 3634                                  */
 3635                                 slab_destroy(cachep, slabp);
 3636                         } else {
 3637                                 list_add(&slabp->list, &l3->slabs_free);
 3638                         }
 3639                 } else {
 3640                         /* Unconditionally move a slab to the end of the
 3641                          * partial list on free - maximum time for the
 3642                          * other objects to be freed, too.
 3643                          */
 3644                         list_add_tail(&slabp->list, &l3->slabs_partial);
 3645                 }
 3646         }
 3647 }
 3648 
 3649 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
 3650 {
 3651         int batchcount;
 3652         struct kmem_list3 *l3;
 3653         int node = numa_mem_id();
 3654 
 3655         batchcount = ac->batchcount;
 3656 #if DEBUG
 3657         BUG_ON(!batchcount || batchcount > ac->avail);
 3658 #endif
 3659         check_irq_off();
 3660         l3 = cachep->nodelists[node];
 3661         spin_lock(&l3->list_lock);
 3662         if (l3->shared) {
 3663                 struct array_cache *shared_array = l3->shared;
 3664                 int max = shared_array->limit - shared_array->avail;
 3665                 if (max) {
 3666                         if (batchcount > max)
 3667                                 batchcount = max;
 3668                         memcpy(&(shared_array->entry[shared_array->avail]),
 3669                                ac->entry, sizeof(void *) * batchcount);
 3670                         shared_array->avail += batchcount;
 3671                         goto free_done;
 3672                 }
 3673         }
 3674 
 3675         free_block(cachep, ac->entry, batchcount, node);
 3676 free_done:
 3677 #if STATS
 3678         {
 3679                 int i = 0;
 3680                 struct list_head *p;
 3681 
 3682                 p = l3->slabs_free.next;
 3683                 while (p != &(l3->slabs_free)) {
 3684                         struct slab *slabp;
 3685 
 3686                         slabp = list_entry(p, struct slab, list);
 3687                         BUG_ON(slabp->inuse);
 3688 
 3689                         i++;
 3690                         p = p->next;
 3691                 }
 3692                 STATS_SET_FREEABLE(cachep, i);
 3693         }
 3694 #endif
 3695         spin_unlock(&l3->list_lock);
 3696         ac->avail -= batchcount;
 3697         memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
 3698 }
 3699 
 3700 /*
 3701  * Release an obj back to its cache. If the obj has a constructed state, it must
 3702  * be in this state _before_ it is released.  Called with disabled ints.
 3703  */
 3704 static inline void __cache_free(struct kmem_cache *cachep, void *objp,
 3705                                 unsigned long caller)
 3706 {
 3707         struct array_cache *ac = cpu_cache_get(cachep);
 3708 
 3709         check_irq_off();
 3710         kmemleak_free_recursive(objp, cachep->flags);
 3711         objp = cache_free_debugcheck(cachep, objp, caller);
 3712 
 3713         kmemcheck_slab_free(cachep, objp, cachep->object_size);
 3714 
 3715         /*
 3716          * Skip calling cache_free_alien() when the platform is not numa.
 3717          * This will avoid cache misses that happen while accessing slabp (which
 3718          * is per page memory  reference) to get nodeid. Instead use a global
 3719          * variable to skip the call, which is mostly likely to be present in
 3720          * the cache.
 3721          */
 3722         if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
 3723                 return;
 3724 
 3725         if (likely(ac->avail < ac->limit)) {
 3726                 STATS_INC_FREEHIT(cachep);
 3727         } else {
 3728                 STATS_INC_FREEMISS(cachep);
 3729                 cache_flusharray(cachep, ac);
 3730         }
 3731 
 3732         ac_put_obj(cachep, ac, objp);
 3733 }
 3734 
 3735 /**
 3736  * kmem_cache_alloc - Allocate an object
 3737  * @cachep: The cache to allocate from.
 3738  * @flags: See kmalloc().
 3739  *
 3740  * Allocate an object from this cache.  The flags are only relevant
 3741  * if the cache has no available objects.
 3742  */
 3743 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 3744 {
 3745         void *ret = slab_alloc(cachep, flags, _RET_IP_);
 3746 
 3747         trace_kmem_cache_alloc(_RET_IP_, ret,
 3748                                cachep->object_size, cachep->size, flags);
 3749 
 3750         return ret;
 3751 }
 3752 EXPORT_SYMBOL(kmem_cache_alloc);
 3753 
 3754 #ifdef CONFIG_TRACING
 3755 void *
 3756 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
 3757 {
 3758         void *ret;
 3759 
 3760         ret = slab_alloc(cachep, flags, _RET_IP_);
 3761 
 3762         trace_kmalloc(_RET_IP_, ret,
 3763                       size, cachep->size, flags);
 3764         return ret;
 3765 }
 3766 EXPORT_SYMBOL(kmem_cache_alloc_trace);
 3767 #endif
 3768 
 3769 #ifdef CONFIG_NUMA
 3770 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
 3771 {
 3772         void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
 3773 
 3774         trace_kmem_cache_alloc_node(_RET_IP_, ret,
 3775                                     cachep->object_size, cachep->size,
 3776                                     flags, nodeid);
 3777 
 3778         return ret;
 3779 }
 3780 EXPORT_SYMBOL(kmem_cache_alloc_node);
 3781 
 3782 #ifdef CONFIG_TRACING
 3783 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
 3784                                   gfp_t flags,
 3785                                   int nodeid,
 3786                                   size_t size)
 3787 {
 3788         void *ret;
 3789 
 3790         ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_);
 3791 
 3792         trace_kmalloc_node(_RET_IP_, ret,
 3793                            size, cachep->size,
 3794                            flags, nodeid);
 3795         return ret;
 3796 }
 3797 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
 3798 #endif
 3799 
 3800 static __always_inline void *
 3801 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
 3802 {
 3803         struct kmem_cache *cachep;
 3804 
 3805         cachep = kmem_find_general_cachep(size, flags);
 3806         if (unlikely(ZERO_OR_NULL_PTR(cachep)))
 3807                 return cachep;
 3808         return kmem_cache_alloc_node_trace(cachep, flags, node, size);
 3809 }
 3810 
 3811 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
 3812 void *__kmalloc_node(size_t size, gfp_t flags, int node)
 3813 {
 3814         return __do_kmalloc_node(size, flags, node, _RET_IP_);
 3815 }
 3816 EXPORT_SYMBOL(__kmalloc_node);
 3817 
 3818 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
 3819                 int node, unsigned long caller)
 3820 {
 3821         return __do_kmalloc_node(size, flags, node, caller);
 3822 }
 3823 EXPORT_SYMBOL(__kmalloc_node_track_caller);
 3824 #else
 3825 void *__kmalloc_node(size_t size, gfp_t flags, int node)
 3826 {
 3827         return __do_kmalloc_node(size, flags, node, 0);
 3828 }
 3829 EXPORT_SYMBOL(__kmalloc_node);
 3830 #endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */
 3831 #endif /* CONFIG_NUMA */
 3832 
 3833 /**
 3834  * __do_kmalloc - allocate memory
 3835  * @size: how many bytes of memory are required.
 3836  * @flags: the type of memory to allocate (see kmalloc).
 3837  * @caller: function caller for debug tracking of the caller
 3838  */
 3839 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
 3840                                           unsigned long caller)
 3841 {
 3842         struct kmem_cache *cachep;
 3843         void *ret;
 3844 
 3845         /* If you want to save a few bytes .text space: replace
 3846          * __ with kmem_.
 3847          * Then kmalloc uses the uninlined functions instead of the inline
 3848          * functions.
 3849          */
 3850         cachep = __find_general_cachep(size, flags);
 3851         if (unlikely(ZERO_OR_NULL_PTR(cachep)))
 3852                 return cachep;
 3853         ret = slab_alloc(cachep, flags, caller);
 3854 
 3855         trace_kmalloc(caller, ret,
 3856                       size, cachep->size, flags);
 3857 
 3858         return ret;
 3859 }
 3860 
 3861 
 3862 #if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
 3863 void *__kmalloc(size_t size, gfp_t flags)
 3864 {
 3865         return __do_kmalloc(size, flags, _RET_IP_);
 3866 }
 3867 EXPORT_SYMBOL(__kmalloc);
 3868 
 3869 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
 3870 {
 3871         return __do_kmalloc(size, flags, caller);
 3872 }
 3873 EXPORT_SYMBOL(__kmalloc_track_caller);
 3874 
 3875 #else
 3876 void *__kmalloc(size_t size, gfp_t flags)
 3877 {
 3878         return __do_kmalloc(size, flags, 0);
 3879 }
 3880 EXPORT_SYMBOL(__kmalloc);
 3881 #endif
 3882 
 3883 /**
 3884  * kmem_cache_free - Deallocate an object
 3885  * @cachep: The cache the allocation was from.
 3886  * @objp: The previously allocated object.
 3887  *
 3888  * Free an object which was previously allocated from this
 3889  * cache.
 3890  */
 3891 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
 3892 {
 3893         unsigned long flags;
 3894         cachep = cache_from_obj(cachep, objp);
 3895         if (!cachep)
 3896                 return;
 3897 
 3898         local_irq_save(flags);
 3899         debug_check_no_locks_freed(objp, cachep->object_size);
 3900         if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
 3901                 debug_check_no_obj_freed(objp, cachep->object_size);
 3902         __cache_free(cachep, objp, _RET_IP_);
 3903         local_irq_restore(flags);
 3904 
 3905         trace_kmem_cache_free(_RET_IP_, objp);
 3906 }
 3907 EXPORT_SYMBOL(kmem_cache_free);
 3908 
 3909 /**
 3910  * kfree - free previously allocated memory
 3911  * @objp: pointer returned by kmalloc.
 3912  *
 3913  * If @objp is NULL, no operation is performed.
 3914  *
 3915  * Don't free memory not originally allocated by kmalloc()
 3916  * or you will run into trouble.
 3917  */
 3918 void kfree(const void *objp)
 3919 {
 3920         struct kmem_cache *c;
 3921         unsigned long flags;
 3922 
 3923         trace_kfree(_RET_IP_, objp);
 3924 
 3925         if (unlikely(ZERO_OR_NULL_PTR(objp)))
 3926                 return;
 3927         local_irq_save(flags);
 3928         kfree_debugcheck(objp);
 3929         c = virt_to_cache(objp);
 3930         debug_check_no_locks_freed(objp, c->object_size);
 3931 
 3932         debug_check_no_obj_freed(objp, c->object_size);
 3933         __cache_free(c, (void *)objp, _RET_IP_);
 3934         local_irq_restore(flags);
 3935 }
 3936 EXPORT_SYMBOL(kfree);
 3937 
 3938 /*
 3939  * This initializes kmem_list3 or resizes various caches for all nodes.
 3940  */
 3941 static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
 3942 {
 3943         int node;
 3944         struct kmem_list3 *l3;
 3945         struct array_cache *new_shared;
 3946         struct array_cache **new_alien = NULL;
 3947 
 3948         for_each_online_node(node) {
 3949 
 3950                 if (use_alien_caches) {
 3951                         new_alien = alloc_alien_cache(node, cachep->limit, gfp);
 3952                         if (!new_alien)
 3953                                 goto fail;
 3954                 }
 3955 
 3956                 new_shared = NULL;
 3957                 if (cachep->shared) {
 3958                         new_shared = alloc_arraycache(node,
 3959                                 cachep->shared*cachep->batchcount,
 3960                                         0xbaadf00d, gfp);
 3961                         if (!new_shared) {
 3962                                 free_alien_cache(new_alien);
 3963                                 goto fail;
 3964                         }
 3965                 }
 3966 
 3967                 l3 = cachep->nodelists[node];
 3968                 if (l3) {
 3969                         struct array_cache *shared = l3->shared;
 3970 
 3971                         spin_lock_irq(&l3->list_lock);
 3972 
 3973                         if (shared)
 3974                                 free_block(cachep, shared->entry,
 3975                                                 shared->avail, node);
 3976 
 3977                         l3->shared = new_shared;
 3978                         if (!l3->alien) {
 3979                                 l3->alien = new_alien;
 3980                                 new_alien = NULL;
 3981                         }
 3982                         l3->free_limit = (1 + nr_cpus_node(node)) *
 3983                                         cachep->batchcount + cachep->num;
 3984                         spin_unlock_irq(&l3->list_lock);
 3985                         kfree(shared);
 3986                         free_alien_cache(new_alien);
 3987                         continue;
 3988                 }
 3989                 l3 = kmalloc_node(sizeof(struct kmem_list3), gfp, node);
 3990                 if (!l3) {
 3991                         free_alien_cache(new_alien);
 3992                         kfree(new_shared);
 3993                         goto fail;
 3994                 }
 3995 
 3996                 kmem_list3_init(l3);
 3997                 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
 3998                                 ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
 3999                 l3->shared = new_shared;
 4000                 l3->alien = new_alien;
 4001                 l3->free_limit = (1 + nr_cpus_node(node)) *
 4002                                         cachep->batchcount + cachep->num;
 4003                 cachep->nodelists[node] = l3;
 4004         }
 4005         return 0;
 4006 
 4007 fail:
 4008         if (!cachep->list.next) {
 4009                 /* Cache is not active yet. Roll back what we did */
 4010                 node--;
 4011                 while (node >= 0) {
 4012                         if (cachep->nodelists[node]) {
 4013                                 l3 = cachep->nodelists[node];
 4014 
 4015                                 kfree(l3->shared);
 4016                                 free_alien_cache(l3->alien);
 4017                                 kfree(l3);
 4018                                 cachep->nodelists[node] = NULL;
 4019                         }
 4020                         node--;
 4021                 }
 4022         }
 4023         return -ENOMEM;
 4024 }
 4025 
 4026 struct ccupdate_struct {
 4027         struct kmem_cache *cachep;
 4028         struct array_cache *new[0];
 4029 };
 4030 
 4031 static void do_ccupdate_local(void *info)
 4032 {
 4033         struct ccupdate_struct *new = info;
 4034         struct array_cache *old;
 4035 
 4036         check_irq_off();
 4037         old = cpu_cache_get(new->cachep);
 4038 
 4039         new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
 4040         new->new[smp_processor_id()] = old;
 4041 }
 4042 
 4043 /* Always called with the slab_mutex held */
 4044 static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
 4045                                 int batchcount, int shared, gfp_t gfp)
 4046 {
 4047         struct ccupdate_struct *new;
 4048         int i;
 4049 
 4050         new = kzalloc(sizeof(*new) + nr_cpu_ids * sizeof(struct array_cache *),
 4051                       gfp);
 4052         if (!new)
 4053                 return -ENOMEM;
 4054 
 4055         for_each_online_cpu(i) {
 4056                 new->new[i] = alloc_arraycache(cpu_to_mem(i), limit,
 4057                                                 batchcount, gfp);
 4058                 if (!new->new[i]) {
 4059                         for (i--; i >= 0; i--)
 4060                                 kfree(new->new[i]);
 4061                         kfree(new);
 4062                         return -ENOMEM;
 4063                 }
 4064         }
 4065         new->cachep = cachep;
 4066 
 4067         on_each_cpu(do_ccupdate_local, (void *)new, 1);
 4068 
 4069         check_irq_on();
 4070         cachep->batchcount = batchcount;
 4071         cachep->limit = limit;
 4072         cachep->shared = shared;
 4073 
 4074         for_each_online_cpu(i) {
 4075                 struct array_cache *ccold = new->new[i];
 4076                 if (!ccold)
 4077                         continue;
 4078                 spin_lock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock);
 4079                 free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i));
 4080                 spin_unlock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock);
 4081                 kfree(ccold);
 4082         }
 4083         kfree(new);
 4084         return alloc_kmemlist(cachep, gfp);
 4085 }
 4086 
 4087 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
 4088                                 int batchcount, int shared, gfp_t gfp)
 4089 {
 4090         int ret;
 4091         struct kmem_cache *c = NULL;
 4092         int i = 0;
 4093 
 4094         ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
 4095 
 4096         if (slab_state < FULL)
 4097                 return ret;
 4098 
 4099         if ((ret < 0) || !is_root_cache(cachep))
 4100                 return ret;
 4101 
 4102         VM_BUG_ON(!mutex_is_locked(&slab_mutex));
 4103         for_each_memcg_cache_index(i) {
 4104                 c = cache_from_memcg(cachep, i);
 4105                 if (c)
 4106                         /* return value determined by the parent cache only */
 4107                         __do_tune_cpucache(c, limit, batchcount, shared, gfp);
 4108         }
 4109 
 4110         return ret;
 4111 }
 4112 
 4113 /* Called with slab_mutex held always */
 4114 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
 4115 {
 4116         int err;
 4117         int limit = 0;
 4118         int shared = 0;
 4119         int batchcount = 0;
 4120 
 4121         if (!is_root_cache(cachep)) {
 4122                 struct kmem_cache *root = memcg_root_cache(cachep);
 4123                 limit = root->limit;
 4124                 shared = root->shared;
 4125                 batchcount = root->batchcount;
 4126         }
 4127 
 4128         if (limit && shared && batchcount)
 4129                 goto skip_setup;
 4130         /*
 4131          * The head array serves three purposes:
 4132          * - create a LIFO ordering, i.e. return objects that are cache-warm
 4133          * - reduce the number of spinlock operations.
 4134          * - reduce the number of linked list operations on the slab and
 4135          *   bufctl chains: array operations are cheaper.
 4136          * The numbers are guessed, we should auto-tune as described by
 4137          * Bonwick.
 4138          */
 4139         if (cachep->size > 131072)
 4140                 limit = 1;
 4141         else if (cachep->size > PAGE_SIZE)
 4142                 limit = 8;
 4143         else if (cachep->size > 1024)
 4144                 limit = 24;
 4145         else if (cachep->size > 256)
 4146                 limit = 54;
 4147         else
 4148                 limit = 120;
 4149 
 4150         /*
 4151          * CPU bound tasks (e.g. network routing) can exhibit cpu bound
 4152          * allocation behaviour: Most allocs on one cpu, most free operations
 4153          * on another cpu. For these cases, an efficient object passing between
 4154          * cpus is necessary. This is provided by a shared array. The array
 4155          * replaces Bonwick's magazine layer.
 4156          * On uniprocessor, it's functionally equivalent (but less efficient)
 4157          * to a larger limit. Thus disabled by default.
 4158          */
 4159         shared = 0;
 4160         if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
 4161                 shared = 8;
 4162 
 4163 #if DEBUG
 4164         /*
 4165          * With debugging enabled, large batchcount lead to excessively long
 4166          * periods with disabled local interrupts. Limit the batchcount
 4167          */
 4168         if (limit > 32)
 4169                 limit = 32;
 4170 #endif
 4171         batchcount = (limit + 1) / 2;
 4172 skip_setup:
 4173         err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
 4174         if (err)
 4175                 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
 4176                        cachep->name, -err);
 4177         return err;
 4178 }
 4179 
 4180 /*
 4181  * Drain an array if it contains any elements taking the l3 lock only if
 4182  * necessary. Note that the l3 listlock also protects the array_cache
 4183  * if drain_array() is used on the shared array.
 4184  */
 4185 static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
 4186                          struct array_cache *ac, int force, int node)
 4187 {
 4188         int tofree;
 4189 
 4190         if (!ac || !ac->avail)
 4191                 return;
 4192         if (ac->touched && !force) {
 4193                 ac->touched = 0;
 4194         } else {
 4195                 spin_lock_irq(&l3->list_lock);
 4196                 if (ac->avail) {
 4197                         tofree = force ? ac->avail : (ac->limit + 4) / 5;
 4198                         if (tofree > ac->avail)
 4199                                 tofree = (ac->avail + 1) / 2;
 4200                         free_block(cachep, ac->entry, tofree, node);
 4201                         ac->avail -= tofree;
 4202                         memmove(ac->entry, &(ac->entry[tofree]),
 4203                                 sizeof(void *) * ac->avail);
 4204                 }
 4205                 spin_unlock_irq(&l3->list_lock);
 4206         }
 4207 }
 4208 
 4209 /**
 4210  * cache_reap - Reclaim memory from caches.
 4211  * @w: work descriptor
 4212  *
 4213  * Called from workqueue/eventd every few seconds.
 4214  * Purpose:
 4215  * - clear the per-cpu caches for this CPU.
 4216  * - return freeable pages to the main free memory pool.
 4217  *
 4218  * If we cannot acquire the cache chain mutex then just give up - we'll try
 4219  * again on the next iteration.
 4220  */
 4221 static void cache_reap(struct work_struct *w)
 4222 {
 4223         struct kmem_cache *searchp;
 4224         struct kmem_list3 *l3;
 4225         int node = numa_mem_id();
 4226         struct delayed_work *work = to_delayed_work(w);
 4227 
 4228         if (!mutex_trylock(&slab_mutex))
 4229                 /* Give up. Setup the next iteration. */
 4230                 goto out;
 4231 
 4232         list_for_each_entry(searchp, &slab_caches, list) {
 4233                 check_irq_on();
 4234 
 4235                 /*
 4236                  * We only take the l3 lock if absolutely necessary and we
 4237                  * have established with reasonable certainty that
 4238                  * we can do some work if the lock was obtained.
 4239                  */
 4240                 l3 = searchp->nodelists[node];
 4241 
 4242                 reap_alien(searchp, l3);
 4243 
 4244                 drain_array(searchp, l3, cpu_cache_get(searchp), 0, node);
 4245 
 4246                 /*
 4247                  * These are racy checks but it does not matter
 4248                  * if we skip one check or scan twice.
 4249                  */
 4250                 if (time_after(l3->next_reap, jiffies))
 4251                         goto next;
 4252 
 4253                 l3->next_reap = jiffies + REAPTIMEOUT_LIST3;
 4254 
 4255                 drain_array(searchp, l3, l3->shared, 0, node);
 4256 
 4257                 if (l3->free_touched)
 4258                         l3->free_touched = 0;
 4259                 else {
 4260                         int freed;
 4261 
 4262                         freed = drain_freelist(searchp, l3, (l3->free_limit +
 4263                                 5 * searchp->num - 1) / (5 * searchp->num));
 4264                         STATS_ADD_REAPED(searchp, freed);
 4265                 }
 4266 next:
 4267                 cond_resched();
 4268         }
 4269         check_irq_on();
 4270         mutex_unlock(&slab_mutex);
 4271         next_reap_node();
 4272 out:
 4273         /* Set up the next iteration */
 4274         schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC));
 4275 }
 4276 
 4277 #ifdef CONFIG_SLABINFO
 4278 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
 4279 {
 4280         struct slab *slabp;
 4281         unsigned long active_objs;
 4282         unsigned long num_objs;
 4283         unsigned long active_slabs = 0;
 4284         unsigned long num_slabs, free_objects = 0, shared_avail = 0;
 4285         const char *name;
 4286         char *error = NULL;
 4287         int node;
 4288         struct kmem_list3 *l3;
 4289 
 4290         active_objs = 0;
 4291         num_slabs = 0;
 4292         for_each_online_node(node) {
 4293                 l3 = cachep->nodelists[node];
 4294                 if (!l3)
 4295                         continue;
 4296 
 4297                 check_irq_on();
 4298                 spin_lock_irq(&l3->list_lock);
 4299 
 4300                 list_for_each_entry(slabp, &l3->slabs_full, list) {
 4301                         if (slabp->inuse != cachep->num && !error)
 4302                                 error = "slabs_full accounting error";
 4303                         active_objs += cachep->num;
 4304                         active_slabs++;
 4305                 }
 4306                 list_for_each_entry(slabp, &l3->slabs_partial, list) {
 4307                         if (slabp->inuse == cachep->num && !error)
 4308                                 error = "slabs_partial inuse accounting error";
 4309                         if (!slabp->inuse && !error)
 4310                                 error = "slabs_partial/inuse accounting error";
 4311                         active_objs += slabp->inuse;
 4312                         active_slabs++;
 4313                 }
 4314                 list_for_each_entry(slabp, &l3->slabs_free, list) {
 4315                         if (slabp->inuse && !error)
 4316                                 error = "slabs_free/inuse accounting error";
 4317                         num_slabs++;
 4318                 }
 4319                 free_objects += l3->free_objects;
 4320                 if (l3->shared)
 4321                         shared_avail += l3->shared->avail;
 4322 
 4323                 spin_unlock_irq(&l3->list_lock);
 4324         }
 4325         num_slabs += active_slabs;
 4326         num_objs = num_slabs * cachep->num;
 4327         if (num_objs - active_objs != free_objects && !error)
 4328                 error = "free_objects accounting error";
 4329 
 4330         name = cachep->name;
 4331         if (error)
 4332                 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
 4333 
 4334         sinfo->active_objs = active_objs;
 4335         sinfo->num_objs = num_objs;
 4336         sinfo->active_slabs = active_slabs;
 4337         sinfo->num_slabs = num_slabs;
 4338         sinfo->shared_avail = shared_avail;
 4339         sinfo->limit = cachep->limit;
 4340         sinfo->batchcount = cachep->batchcount;
 4341         sinfo->shared = cachep->shared;
 4342         sinfo->objects_per_slab = cachep->num;
 4343         sinfo->cache_order = cachep->gfporder;
 4344 }
 4345 
 4346 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
 4347 {
 4348 #if STATS
 4349         {                       /* list3 stats */
 4350                 unsigned long high = cachep->high_mark;
 4351                 unsigned long allocs = cachep->num_allocations;
 4352                 unsigned long grown = cachep->grown;
 4353                 unsigned long reaped = cachep->reaped;
 4354                 unsigned long errors = cachep->errors;
 4355                 unsigned long max_freeable = cachep->max_freeable;
 4356                 unsigned long node_allocs = cachep->node_allocs;
 4357                 unsigned long node_frees = cachep->node_frees;
 4358                 unsigned long overflows = cachep->node_overflow;
 4359 
 4360                 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu "
 4361                            "%4lu %4lu %4lu %4lu %4lu",
 4362                            allocs, high, grown,
 4363                            reaped, errors, max_freeable, node_allocs,
 4364                            node_frees, overflows);
 4365         }
 4366         /* cpu stats */
 4367         {
 4368                 unsigned long allochit = atomic_read(&cachep->allochit);
 4369                 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
 4370                 unsigned long freehit = atomic_read(&cachep->freehit);
 4371                 unsigned long freemiss = atomic_read(&cachep->freemiss);
 4372 
 4373                 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
 4374                            allochit, allocmiss, freehit, freemiss);
 4375         }
 4376 #endif
 4377 }
 4378 
 4379 #define MAX_SLABINFO_WRITE 128
 4380 /**
 4381  * slabinfo_write - Tuning for the slab allocator
 4382  * @file: unused
 4383  * @buffer: user buffer
 4384  * @count: data length
 4385  * @ppos: unused
 4386  */
 4387 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
 4388                        size_t count, loff_t *ppos)
 4389 {
 4390         char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
 4391         int limit, batchcount, shared, res;
 4392         struct kmem_cache *cachep;
 4393 
 4394         if (count > MAX_SLABINFO_WRITE)
 4395                 return -EINVAL;
 4396         if (copy_from_user(&kbuf, buffer, count))
 4397                 return -EFAULT;
 4398         kbuf[MAX_SLABINFO_WRITE] = '\0';
 4399 
 4400         tmp = strchr(kbuf, ' ');
 4401         if (!tmp)
 4402                 return -EINVAL;
 4403         *tmp = '\0';
 4404         tmp++;
 4405         if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
 4406                 return -EINVAL;
 4407 
 4408         /* Find the cache in the chain of caches. */
 4409         mutex_lock(&slab_mutex);
 4410         res = -EINVAL;
 4411         list_for_each_entry(cachep, &slab_caches, list) {
 4412                 if (!strcmp(cachep->name, kbuf)) {
 4413                         if (limit < 1 || batchcount < 1 ||
 4414                                         batchcount > limit || shared < 0) {
 4415                                 res = 0;
 4416                         } else {
 4417                                 res = do_tune_cpucache(cachep, limit,
 4418                                                        batchcount, shared,
 4419                                                        GFP_KERNEL);
 4420                         }
 4421                         break;
 4422                 }
 4423         }
 4424         mutex_unlock(&slab_mutex);
 4425         if (res >= 0)
 4426                 res = count;
 4427         return res;
 4428 }
 4429 
 4430 #ifdef CONFIG_DEBUG_SLAB_LEAK
 4431 
 4432 static void *leaks_start(struct seq_file *m, loff_t *pos)
 4433 {
 4434         mutex_lock(&slab_mutex);
 4435         return seq_list_start(&slab_caches, *pos);
 4436 }
 4437 
 4438 static inline int add_caller(unsigned long *n, unsigned long v)
 4439 {
 4440         unsigned long *p;
 4441         int l;
 4442         if (!v)
 4443                 return 1;
 4444         l = n[1];
 4445         p = n + 2;
 4446         while (l) {
 4447                 int i = l/2;
 4448                 unsigned long *q = p + 2 * i;
 4449                 if (*q == v) {
 4450                         q[1]++;
 4451                         return 1;
 4452                 }
 4453                 if (*q > v) {
 4454                         l = i;
 4455                 } else {
 4456                         p = q + 2;
 4457                         l -= i + 1;
 4458                 }
 4459         }
 4460         if (++n[1] == n[0])
 4461                 return 0;
 4462         memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n));
 4463         p[0] = v;
 4464         p[1] = 1;
 4465         return 1;
 4466 }
 4467 
 4468 static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s)
 4469 {
 4470         void *p;
 4471         int i;
 4472         if (n[0] == n[1])
 4473                 return;
 4474         for (i = 0, p = s->s_mem; i < c->num; i++, p += c->size) {
 4475                 if (slab_bufctl(s)[i] != BUFCTL_ACTIVE)
 4476                         continue;
 4477                 if (!add_caller(n, (unsigned long)*dbg_userword(c, p)))
 4478                         return;
 4479         }
 4480 }
 4481 
 4482 static void show_symbol(struct seq_file *m, unsigned long address)
 4483 {
 4484 #ifdef CONFIG_KALLSYMS
 4485         unsigned long offset, size;
 4486         char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN];
 4487 
 4488         if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) {
 4489                 seq_printf(m, "%s+%#lx/%#lx", name, offset, size);
 4490                 if (modname[0])
 4491                         seq_printf(m, " [%s]", modname);
 4492                 return;
 4493         }
 4494 #endif
 4495         seq_printf(m, "%p", (void *)address);
 4496 }
 4497 
 4498 static int leaks_show(struct seq_file *m, void *p)
 4499 {
 4500         struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list);
 4501         struct slab *slabp;
 4502         struct kmem_list3 *l3;
 4503         const char *name;
 4504         unsigned long *n = m->private;
 4505         int node;
 4506         int i;
 4507 
 4508         if (!(cachep->flags & SLAB_STORE_USER))
 4509                 return 0;
 4510         if (!(cachep->flags & SLAB_RED_ZONE))
 4511                 return 0;
 4512 
 4513         /* OK, we can do it */
 4514 
 4515         n[1] = 0;
 4516 
 4517         for_each_online_node(node) {
 4518                 l3 = cachep->nodelists[node];
 4519                 if (!l3)
 4520                         continue;
 4521 
 4522                 check_irq_on();
 4523                 spin_lock_irq(&l3->list_lock);
 4524 
 4525                 list_for_each_entry(slabp, &l3->slabs_full, list)
 4526                         handle_slab(n, cachep, slabp);
 4527                 list_for_each_entry(slabp, &l3->slabs_partial, list)
 4528                         handle_slab(n, cachep, slabp);
 4529                 spin_unlock_irq(&l3->list_lock);
 4530         }
 4531         name = cachep->name;
 4532         if (n[0] == n[1]) {
 4533                 /* Increase the buffer size */
 4534                 mutex_unlock(&slab_mutex);
 4535                 m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL);
 4536                 if (!m->private) {
 4537                         /* Too bad, we are really out */
 4538                         m->private = n;
 4539                         mutex_lock(&slab_mutex);
 4540                         return -ENOMEM;
 4541                 }
 4542                 *(unsigned long *)m->private = n[0] * 2;
 4543                 kfree(n);
 4544                 mutex_lock(&slab_mutex);
 4545                 /* Now make sure this entry will be retried */
 4546                 m->count = m->size;
 4547                 return 0;
 4548         }
 4549         for (i = 0; i < n[1]; i++) {
 4550                 seq_printf(m, "%s: %lu ", name, n[2*i+3]);
 4551                 show_symbol(m, n[2*i+2]);
 4552                 seq_putc(m, '\n');
 4553         }
 4554 
 4555         return 0;
 4556 }
 4557 
 4558 static void *s_next(struct seq_file *m, void *p, loff_t *pos)
 4559 {
 4560         return seq_list_next(p, &slab_caches, pos);
 4561 }
 4562 
 4563 static void s_stop(struct seq_file *m, void *p)
 4564 {
 4565         mutex_unlock(&slab_mutex);
 4566 }
 4567 
 4568 static const struct seq_operations slabstats_op = {
 4569         .start = leaks_start,
 4570         .next = s_next,
 4571         .stop = s_stop,
 4572         .show = leaks_show,
 4573 };
 4574 
 4575 static int slabstats_open(struct inode *inode, struct file *file)
 4576 {
 4577         unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL);
 4578         int ret = -ENOMEM;
 4579         if (n) {
 4580                 ret = seq_open(file, &slabstats_op);
 4581                 if (!ret) {
 4582                         struct seq_file *m = file->private_data;
 4583                         *n = PAGE_SIZE / (2 * sizeof(unsigned long));
 4584                         m->private = n;
 4585                         n = NULL;
 4586                 }
 4587                 kfree(n);
 4588         }
 4589         return ret;
 4590 }
 4591 
 4592 static const struct file_operations proc_slabstats_operations = {
 4593         .open           = slabstats_open,
 4594         .read           = seq_read,
 4595         .llseek         = seq_lseek,
 4596         .release        = seq_release_private,
 4597 };
 4598 #endif
 4599 
 4600 static int __init slab_proc_init(void)
 4601 {
 4602 #ifdef CONFIG_DEBUG_SLAB_LEAK
 4603         proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations);
 4604 #endif
 4605         return 0;
 4606 }
 4607 module_init(slab_proc_init);
 4608 #endif
 4609 
 4610 /**
 4611  * ksize - get the actual amount of memory allocated for a given object
 4612  * @objp: Pointer to the object
 4613  *
 4614  * kmalloc may internally round up allocations and return more memory
 4615  * than requested. ksize() can be used to determine the actual amount of
 4616  * memory allocated. The caller may use this additional memory, even though
 4617  * a smaller amount of memory was initially specified with the kmalloc call.
 4618  * The caller must guarantee that objp points to a valid object previously
 4619  * allocated with either kmalloc() or kmem_cache_alloc(). The object
 4620  * must not be freed during the duration of the call.
 4621  */
 4622 size_t ksize(const void *objp)
 4623 {
 4624         BUG_ON(!objp);
 4625         if (unlikely(objp == ZERO_SIZE_PTR))
 4626                 return 0;
 4627 
 4628         return virt_to_cache(objp)->object_size;
 4629 }
 4630 EXPORT_SYMBOL(ksize);

Cache object: d37777b03eb4b859baf2a649c3683225


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