linux/mm/slub.c
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   1/*
   2 * SLUB: A slab allocator that limits cache line use instead of queuing
   3 * objects in per cpu and per node lists.
   4 *
   5 * The allocator synchronizes using per slab locks or atomic operatios
   6 * and only uses a centralized lock to manage a pool of partial slabs.
   7 *
   8 * (C) 2007 SGI, Christoph Lameter
   9 * (C) 2011 Linux Foundation, Christoph Lameter
  10 */
  11
  12#include <linux/mm.h>
  13#include <linux/swap.h> /* struct reclaim_state */
  14#include <linux/module.h>
  15#include <linux/bit_spinlock.h>
  16#include <linux/interrupt.h>
  17#include <linux/bitops.h>
  18#include <linux/slab.h>
  19#include <linux/proc_fs.h>
  20#include <linux/seq_file.h>
  21#include <linux/kmemcheck.h>
  22#include <linux/cpu.h>
  23#include <linux/cpuset.h>
  24#include <linux/mempolicy.h>
  25#include <linux/ctype.h>
  26#include <linux/debugobjects.h>
  27#include <linux/kallsyms.h>
  28#include <linux/memory.h>
  29#include <linux/math64.h>
  30#include <linux/fault-inject.h>
  31#include <linux/stacktrace.h>
  32
  33#include <trace/events/kmem.h>
  34
  35/*
  36 * Lock order:
  37 *   1. slub_lock (Global Semaphore)
  38 *   2. node->list_lock
  39 *   3. slab_lock(page) (Only on some arches and for debugging)
  40 *
  41 *   slub_lock
  42 *
  43 *   The role of the slub_lock is to protect the list of all the slabs
  44 *   and to synchronize major metadata changes to slab cache structures.
  45 *
  46 *   The slab_lock is only used for debugging and on arches that do not
  47 *   have the ability to do a cmpxchg_double. It only protects the second
  48 *   double word in the page struct. Meaning
  49 *      A. page->freelist       -> List of object free in a page
  50 *      B. page->counters       -> Counters of objects
  51 *      C. page->frozen         -> frozen state
  52 *
  53 *   If a slab is frozen then it is exempt from list management. It is not
  54 *   on any list. The processor that froze the slab is the one who can
  55 *   perform list operations on the page. Other processors may put objects
  56 *   onto the freelist but the processor that froze the slab is the only
  57 *   one that can retrieve the objects from the page's freelist.
  58 *
  59 *   The list_lock protects the partial and full list on each node and
  60 *   the partial slab counter. If taken then no new slabs may be added or
  61 *   removed from the lists nor make the number of partial slabs be modified.
  62 *   (Note that the total number of slabs is an atomic value that may be
  63 *   modified without taking the list lock).
  64 *
  65 *   The list_lock is a centralized lock and thus we avoid taking it as
  66 *   much as possible. As long as SLUB does not have to handle partial
  67 *   slabs, operations can continue without any centralized lock. F.e.
  68 *   allocating a long series of objects that fill up slabs does not require
  69 *   the list lock.
  70 *   Interrupts are disabled during allocation and deallocation in order to
  71 *   make the slab allocator safe to use in the context of an irq. In addition
  72 *   interrupts are disabled to ensure that the processor does not change
  73 *   while handling per_cpu slabs, due to kernel preemption.
  74 *
  75 * SLUB assigns one slab for allocation to each processor.
  76 * Allocations only occur from these slabs called cpu slabs.
  77 *
  78 * Slabs with free elements are kept on a partial list and during regular
  79 * operations no list for full slabs is used. If an object in a full slab is
  80 * freed then the slab will show up again on the partial lists.
  81 * We track full slabs for debugging purposes though because otherwise we
  82 * cannot scan all objects.
  83 *
  84 * Slabs are freed when they become empty. Teardown and setup is
  85 * minimal so we rely on the page allocators per cpu caches for
  86 * fast frees and allocs.
  87 *
  88 * Overloading of page flags that are otherwise used for LRU management.
  89 *
  90 * PageActive           The slab is frozen and exempt from list processing.
  91 *                      This means that the slab is dedicated to a purpose
  92 *                      such as satisfying allocations for a specific
  93 *                      processor. Objects may be freed in the slab while
  94 *                      it is frozen but slab_free will then skip the usual
  95 *                      list operations. It is up to the processor holding
  96 *                      the slab to integrate the slab into the slab lists
  97 *                      when the slab is no longer needed.
  98 *
  99 *                      One use of this flag is to mark slabs that are
 100 *                      used for allocations. Then such a slab becomes a cpu
 101 *                      slab. The cpu slab may be equipped with an additional
 102 *                      freelist that allows lockless access to
 103 *                      free objects in addition to the regular freelist
 104 *                      that requires the slab lock.
 105 *
 106 * PageError            Slab requires special handling due to debug
 107 *                      options set. This moves slab handling out of
 108 *                      the fast path and disables lockless freelists.
 109 */
 110
 111#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 112                SLAB_TRACE | SLAB_DEBUG_FREE)
 113
 114static inline int kmem_cache_debug(struct kmem_cache *s)
 115{
 116#ifdef CONFIG_SLUB_DEBUG
 117        return unlikely(s->flags & SLAB_DEBUG_FLAGS);
 118#else
 119        return 0;
 120#endif
 121}
 122
 123/*
 124 * Issues still to be resolved:
 125 *
 126 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
 127 *
 128 * - Variable sizing of the per node arrays
 129 */
 130
 131/* Enable to test recovery from slab corruption on boot */
 132#undef SLUB_RESILIENCY_TEST
 133
 134/* Enable to log cmpxchg failures */
 135#undef SLUB_DEBUG_CMPXCHG
 136
 137/*
 138 * Mininum number of partial slabs. These will be left on the partial
 139 * lists even if they are empty. kmem_cache_shrink may reclaim them.
 140 */
 141#define MIN_PARTIAL 5
 142
 143/*
 144 * Maximum number of desirable partial slabs.
 145 * The existence of more partial slabs makes kmem_cache_shrink
 146 * sort the partial list by the number of objects in the.
 147 */
 148#define MAX_PARTIAL 10
 149
 150#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
 151                                SLAB_POISON | SLAB_STORE_USER)
 152
 153/*
 154 * Debugging flags that require metadata to be stored in the slab.  These get
 155 * disabled when slub_debug=O is used and a cache's min order increases with
 156 * metadata.
 157 */
 158#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 159
 160/*
 161 * Set of flags that will prevent slab merging
 162 */
 163#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 164                SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
 165                SLAB_FAILSLAB)
 166
 167#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
 168                SLAB_CACHE_DMA | SLAB_NOTRACK)
 169
 170#define OO_SHIFT        16
 171#define OO_MASK         ((1 << OO_SHIFT) - 1)
 172#define MAX_OBJS_PER_PAGE       32767 /* since page.objects is u15 */
 173
 174/* Internal SLUB flags */
 175#define __OBJECT_POISON         0x80000000UL /* Poison object */
 176#define __CMPXCHG_DOUBLE        0x40000000UL /* Use cmpxchg_double */
 177
 178static int kmem_size = sizeof(struct kmem_cache);
 179
 180#ifdef CONFIG_SMP
 181static struct notifier_block slab_notifier;
 182#endif
 183
 184static enum {
 185        DOWN,           /* No slab functionality available */
 186        PARTIAL,        /* Kmem_cache_node works */
 187        UP,             /* Everything works but does not show up in sysfs */
 188        SYSFS           /* Sysfs up */
 189} slab_state = DOWN;
 190
 191/* A list of all slab caches on the system */
 192static DECLARE_RWSEM(slub_lock);
 193static LIST_HEAD(slab_caches);
 194
 195/*
 196 * Tracking user of a slab.
 197 */
 198#define TRACK_ADDRS_COUNT 16
 199struct track {
 200        unsigned long addr;     /* Called from address */
 201#ifdef CONFIG_STACKTRACE
 202        unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
 203#endif
 204        int cpu;                /* Was running on cpu */
 205        int pid;                /* Pid context */
 206        unsigned long when;     /* When did the operation occur */
 207};
 208
 209enum track_item { TRACK_ALLOC, TRACK_FREE };
 210
 211#ifdef CONFIG_SYSFS
 212static int sysfs_slab_add(struct kmem_cache *);
 213static int sysfs_slab_alias(struct kmem_cache *, const char *);
 214static void sysfs_slab_remove(struct kmem_cache *);
 215
 216#else
 217static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 218static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
 219                                                        { return 0; }
 220static inline void sysfs_slab_remove(struct kmem_cache *s)
 221{
 222        kfree(s->name);
 223        kfree(s);
 224}
 225
 226#endif
 227
 228static inline void stat(const struct kmem_cache *s, enum stat_item si)
 229{
 230#ifdef CONFIG_SLUB_STATS
 231        __this_cpu_inc(s->cpu_slab->stat[si]);
 232#endif
 233}
 234
 235/********************************************************************
 236 *                      Core slab cache functions
 237 *******************************************************************/
 238
 239int slab_is_available(void)
 240{
 241        return slab_state >= UP;
 242}
 243
 244static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 245{
 246        return s->node[node];
 247}
 248
 249/* Verify that a pointer has an address that is valid within a slab page */
 250static inline int check_valid_pointer(struct kmem_cache *s,
 251                                struct page *page, const void *object)
 252{
 253        void *base;
 254
 255        if (!object)
 256                return 1;
 257
 258        base = page_address(page);
 259        if (object < base || object >= base + page->objects * s->size ||
 260                (object - base) % s->size) {
 261                return 0;
 262        }
 263
 264        return 1;
 265}
 266
 267static inline void *get_freepointer(struct kmem_cache *s, void *object)
 268{
 269        return *(void **)(object + s->offset);
 270}
 271
 272static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 273{
 274        void *p;
 275
 276#ifdef CONFIG_DEBUG_PAGEALLOC
 277        probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
 278#else
 279        p = get_freepointer(s, object);
 280#endif
 281        return p;
 282}
 283
 284static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
 285{
 286        *(void **)(object + s->offset) = fp;
 287}
 288
 289/* Loop over all objects in a slab */
 290#define for_each_object(__p, __s, __addr, __objects) \
 291        for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
 292                        __p += (__s)->size)
 293
 294/* Determine object index from a given position */
 295static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
 296{
 297        return (p - addr) / s->size;
 298}
 299
 300static inline size_t slab_ksize(const struct kmem_cache *s)
 301{
 302#ifdef CONFIG_SLUB_DEBUG
 303        /*
 304         * Debugging requires use of the padding between object
 305         * and whatever may come after it.
 306         */
 307        if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
 308                return s->objsize;
 309
 310#endif
 311        /*
 312         * If we have the need to store the freelist pointer
 313         * back there or track user information then we can
 314         * only use the space before that information.
 315         */
 316        if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
 317                return s->inuse;
 318        /*
 319         * Else we can use all the padding etc for the allocation
 320         */
 321        return s->size;
 322}
 323
 324static inline int order_objects(int order, unsigned long size, int reserved)
 325{
 326        return ((PAGE_SIZE << order) - reserved) / size;
 327}
 328
 329static inline struct kmem_cache_order_objects oo_make(int order,
 330                unsigned long size, int reserved)
 331{
 332        struct kmem_cache_order_objects x = {
 333                (order << OO_SHIFT) + order_objects(order, size, reserved)
 334        };
 335
 336        return x;
 337}
 338
 339static inline int oo_order(struct kmem_cache_order_objects x)
 340{
 341        return x.x >> OO_SHIFT;
 342}
 343
 344static inline int oo_objects(struct kmem_cache_order_objects x)
 345{
 346        return x.x & OO_MASK;
 347}
 348
 349/*
 350 * Per slab locking using the pagelock
 351 */
 352static __always_inline void slab_lock(struct page *page)
 353{
 354        bit_spin_lock(PG_locked, &page->flags);
 355}
 356
 357static __always_inline void slab_unlock(struct page *page)
 358{
 359        __bit_spin_unlock(PG_locked, &page->flags);
 360}
 361
 362/* Interrupts must be disabled (for the fallback code to work right) */
 363static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 364                void *freelist_old, unsigned long counters_old,
 365                void *freelist_new, unsigned long counters_new,
 366                const char *n)
 367{
 368        VM_BUG_ON(!irqs_disabled());
 369#ifdef CONFIG_CMPXCHG_DOUBLE
 370        if (s->flags & __CMPXCHG_DOUBLE) {
 371                if (cmpxchg_double(&page->freelist,
 372                        freelist_old, counters_old,
 373                        freelist_new, counters_new))
 374                return 1;
 375        } else
 376#endif
 377        {
 378                slab_lock(page);
 379                if (page->freelist == freelist_old && page->counters == counters_old) {
 380                        page->freelist = freelist_new;
 381                        page->counters = counters_new;
 382                        slab_unlock(page);
 383                        return 1;
 384                }
 385                slab_unlock(page);
 386        }
 387
 388        cpu_relax();
 389        stat(s, CMPXCHG_DOUBLE_FAIL);
 390
 391#ifdef SLUB_DEBUG_CMPXCHG
 392        printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
 393#endif
 394
 395        return 0;
 396}
 397
 398static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 399                void *freelist_old, unsigned long counters_old,
 400                void *freelist_new, unsigned long counters_new,
 401                const char *n)
 402{
 403#ifdef CONFIG_CMPXCHG_DOUBLE
 404        if (s->flags & __CMPXCHG_DOUBLE) {
 405                if (cmpxchg_double(&page->freelist,
 406                        freelist_old, counters_old,
 407                        freelist_new, counters_new))
 408                return 1;
 409        } else
 410#endif
 411        {
 412                unsigned long flags;
 413
 414                local_irq_save(flags);
 415                slab_lock(page);
 416                if (page->freelist == freelist_old && page->counters == counters_old) {
 417                        page->freelist = freelist_new;
 418                        page->counters = counters_new;
 419                        slab_unlock(page);
 420                        local_irq_restore(flags);
 421                        return 1;
 422                }
 423                slab_unlock(page);
 424                local_irq_restore(flags);
 425        }
 426
 427        cpu_relax();
 428        stat(s, CMPXCHG_DOUBLE_FAIL);
 429
 430#ifdef SLUB_DEBUG_CMPXCHG
 431        printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
 432#endif
 433
 434        return 0;
 435}
 436
 437#ifdef CONFIG_SLUB_DEBUG
 438/*
 439 * Determine a map of object in use on a page.
 440 *
 441 * Node listlock must be held to guarantee that the page does
 442 * not vanish from under us.
 443 */
 444static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
 445{
 446        void *p;
 447        void *addr = page_address(page);
 448
 449        for (p = page->freelist; p; p = get_freepointer(s, p))
 450                set_bit(slab_index(p, s, addr), map);
 451}
 452
 453/*
 454 * Debug settings:
 455 */
 456#ifdef CONFIG_SLUB_DEBUG_ON
 457static int slub_debug = DEBUG_DEFAULT_FLAGS;
 458#else
 459static int slub_debug;
 460#endif
 461
 462static char *slub_debug_slabs;
 463static int disable_higher_order_debug;
 464
 465/*
 466 * Object debugging
 467 */
 468static void print_section(char *text, u8 *addr, unsigned int length)
 469{
 470        int i, offset;
 471        int newline = 1;
 472        char ascii[17];
 473
 474        ascii[16] = 0;
 475
 476        for (i = 0; i < length; i++) {
 477                if (newline) {
 478                        printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
 479                        newline = 0;
 480                }
 481                printk(KERN_CONT " %02x", addr[i]);
 482                offset = i % 16;
 483                ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
 484                if (offset == 15) {
 485                        printk(KERN_CONT " %s\n", ascii);
 486                        newline = 1;
 487                }
 488        }
 489        if (!newline) {
 490                i %= 16;
 491                while (i < 16) {
 492                        printk(KERN_CONT "   ");
 493                        ascii[i] = ' ';
 494                        i++;
 495                }
 496                printk(KERN_CONT " %s\n", ascii);
 497        }
 498}
 499
 500static struct track *get_track(struct kmem_cache *s, void *object,
 501        enum track_item alloc)
 502{
 503        struct track *p;
 504
 505        if (s->offset)
 506                p = object + s->offset + sizeof(void *);
 507        else
 508                p = object + s->inuse;
 509
 510        return p + alloc;
 511}
 512
 513static void set_track(struct kmem_cache *s, void *object,
 514                        enum track_item alloc, unsigned long addr)
 515{
 516        struct track *p = get_track(s, object, alloc);
 517
 518        if (addr) {
 519#ifdef CONFIG_STACKTRACE
 520                struct stack_trace trace;
 521                int i;
 522
 523                trace.nr_entries = 0;
 524                trace.max_entries = TRACK_ADDRS_COUNT;
 525                trace.entries = p->addrs;
 526                trace.skip = 3;
 527                save_stack_trace(&trace);
 528
 529                /* See rant in lockdep.c */
 530                if (trace.nr_entries != 0 &&
 531                    trace.entries[trace.nr_entries - 1] == ULONG_MAX)
 532                        trace.nr_entries--;
 533
 534                for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
 535                        p->addrs[i] = 0;
 536#endif
 537                p->addr = addr;
 538                p->cpu = smp_processor_id();
 539                p->pid = current->pid;
 540                p->when = jiffies;
 541        } else
 542                memset(p, 0, sizeof(struct track));
 543}
 544
 545static void init_tracking(struct kmem_cache *s, void *object)
 546{
 547        if (!(s->flags & SLAB_STORE_USER))
 548                return;
 549
 550        set_track(s, object, TRACK_FREE, 0UL);
 551        set_track(s, object, TRACK_ALLOC, 0UL);
 552}
 553
 554static void print_track(const char *s, struct track *t)
 555{
 556        if (!t->addr)
 557                return;
 558
 559        printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
 560                s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
 561#ifdef CONFIG_STACKTRACE
 562        {
 563                int i;
 564                for (i = 0; i < TRACK_ADDRS_COUNT; i++)
 565                        if (t->addrs[i])
 566                                printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
 567                        else
 568                                break;
 569        }
 570#endif
 571}
 572
 573static void print_tracking(struct kmem_cache *s, void *object)
 574{
 575        if (!(s->flags & SLAB_STORE_USER))
 576                return;
 577
 578        print_track("Allocated", get_track(s, object, TRACK_ALLOC));
 579        print_track("Freed", get_track(s, object, TRACK_FREE));
 580}
 581
 582static void print_page_info(struct page *page)
 583{
 584        printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
 585                page, page->objects, page->inuse, page->freelist, page->flags);
 586
 587}
 588
 589static void slab_bug(struct kmem_cache *s, char *fmt, ...)
 590{
 591        va_list args;
 592        char buf[100];
 593
 594        va_start(args, fmt);
 595        vsnprintf(buf, sizeof(buf), fmt, args);
 596        va_end(args);
 597        printk(KERN_ERR "========================================"
 598                        "=====================================\n");
 599        printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
 600        printk(KERN_ERR "----------------------------------------"
 601                        "-------------------------------------\n\n");
 602}
 603
 604static void slab_fix(struct kmem_cache *s, char *fmt, ...)
 605{
 606        va_list args;
 607        char buf[100];
 608
 609        va_start(args, fmt);
 610        vsnprintf(buf, sizeof(buf), fmt, args);
 611        va_end(args);
 612        printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
 613}
 614
 615static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 616{
 617        unsigned int off;       /* Offset of last byte */
 618        u8 *addr = page_address(page);
 619
 620        print_tracking(s, p);
 621
 622        print_page_info(page);
 623
 624        printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
 625                        p, p - addr, get_freepointer(s, p));
 626
 627        if (p > addr + 16)
 628                print_section("Bytes b4", p - 16, 16);
 629
 630        print_section("Object", p, min_t(unsigned long, s->objsize, PAGE_SIZE));
 631
 632        if (s->flags & SLAB_RED_ZONE)
 633                print_section("Redzone", p + s->objsize,
 634                        s->inuse - s->objsize);
 635
 636        if (s->offset)
 637                off = s->offset + sizeof(void *);
 638        else
 639                off = s->inuse;
 640
 641        if (s->flags & SLAB_STORE_USER)
 642                off += 2 * sizeof(struct track);
 643
 644        if (off != s->size)
 645                /* Beginning of the filler is the free pointer */
 646                print_section("Padding", p + off, s->size - off);
 647
 648        dump_stack();
 649}
 650
 651static void object_err(struct kmem_cache *s, struct page *page,
 652                        u8 *object, char *reason)
 653{
 654        slab_bug(s, "%s", reason);
 655        print_trailer(s, page, object);
 656}
 657
 658static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
 659{
 660        va_list args;
 661        char buf[100];
 662
 663        va_start(args, fmt);
 664        vsnprintf(buf, sizeof(buf), fmt, args);
 665        va_end(args);
 666        slab_bug(s, "%s", buf);
 667        print_page_info(page);
 668        dump_stack();
 669}
 670
 671static void init_object(struct kmem_cache *s, void *object, u8 val)
 672{
 673        u8 *p = object;
 674
 675        if (s->flags & __OBJECT_POISON) {
 676                memset(p, POISON_FREE, s->objsize - 1);
 677                p[s->objsize - 1] = POISON_END;
 678        }
 679
 680        if (s->flags & SLAB_RED_ZONE)
 681                memset(p + s->objsize, val, s->inuse - s->objsize);
 682}
 683
 684static u8 *check_bytes8(u8 *start, u8 value, unsigned int bytes)
 685{
 686        while (bytes) {
 687                if (*start != value)
 688                        return start;
 689                start++;
 690                bytes--;
 691        }
 692        return NULL;
 693}
 694
 695static u8 *check_bytes(u8 *start, u8 value, unsigned int bytes)
 696{
 697        u64 value64;
 698        unsigned int words, prefix;
 699
 700        if (bytes <= 16)
 701                return check_bytes8(start, value, bytes);
 702
 703        value64 = value | value << 8 | value << 16 | value << 24;
 704        value64 = (value64 & 0xffffffff) | value64 << 32;
 705        prefix = 8 - ((unsigned long)start) % 8;
 706
 707        if (prefix) {
 708                u8 *r = check_bytes8(start, value, prefix);
 709                if (r)
 710                        return r;
 711                start += prefix;
 712                bytes -= prefix;
 713        }
 714
 715        words = bytes / 8;
 716
 717        while (words) {
 718                if (*(u64 *)start != value64)
 719                        return check_bytes8(start, value, 8);
 720                start += 8;
 721                words--;
 722        }
 723
 724        return check_bytes8(start, value, bytes % 8);
 725}
 726
 727static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
 728                                                void *from, void *to)
 729{
 730        slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
 731        memset(from, data, to - from);
 732}
 733
 734static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
 735                        u8 *object, char *what,
 736                        u8 *start, unsigned int value, unsigned int bytes)
 737{
 738        u8 *fault;
 739        u8 *end;
 740
 741        fault = check_bytes(start, value, bytes);
 742        if (!fault)
 743                return 1;
 744
 745        end = start + bytes;
 746        while (end > fault && end[-1] == value)
 747                end--;
 748
 749        slab_bug(s, "%s overwritten", what);
 750        printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
 751                                        fault, end - 1, fault[0], value);
 752        print_trailer(s, page, object);
 753
 754        restore_bytes(s, what, value, fault, end);
 755        return 0;
 756}
 757
 758/*
 759 * Object layout:
 760 *
 761 * object address
 762 *      Bytes of the object to be managed.
 763 *      If the freepointer may overlay the object then the free
 764 *      pointer is the first word of the object.
 765 *
 766 *      Poisoning uses 0x6b (POISON_FREE) and the last byte is
 767 *      0xa5 (POISON_END)
 768 *
 769 * object + s->objsize
 770 *      Padding to reach word boundary. This is also used for Redzoning.
 771 *      Padding is extended by another word if Redzoning is enabled and
 772 *      objsize == inuse.
 773 *
 774 *      We fill with 0xbb (RED_INACTIVE) for inactive objects and with
 775 *      0xcc (RED_ACTIVE) for objects in use.
 776 *
 777 * object + s->inuse
 778 *      Meta data starts here.
 779 *
 780 *      A. Free pointer (if we cannot overwrite object on free)
 781 *      B. Tracking data for SLAB_STORE_USER
 782 *      C. Padding to reach required alignment boundary or at mininum
 783 *              one word if debugging is on to be able to detect writes
 784 *              before the word boundary.
 785 *
 786 *      Padding is done using 0x5a (POISON_INUSE)
 787 *
 788 * object + s->size
 789 *      Nothing is used beyond s->size.
 790 *
 791 * If slabcaches are merged then the objsize and inuse boundaries are mostly
 792 * ignored. And therefore no slab options that rely on these boundaries
 793 * may be used with merged slabcaches.
 794 */
 795
 796static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
 797{
 798        unsigned long off = s->inuse;   /* The end of info */
 799
 800        if (s->offset)
 801                /* Freepointer is placed after the object. */
 802                off += sizeof(void *);
 803
 804        if (s->flags & SLAB_STORE_USER)
 805                /* We also have user information there */
 806                off += 2 * sizeof(struct track);
 807
 808        if (s->size == off)
 809                return 1;
 810
 811        return check_bytes_and_report(s, page, p, "Object padding",
 812                                p + off, POISON_INUSE, s->size - off);
 813}
 814
 815/* Check the pad bytes at the end of a slab page */
 816static int slab_pad_check(struct kmem_cache *s, struct page *page)
 817{
 818        u8 *start;
 819        u8 *fault;
 820        u8 *end;
 821        int length;
 822        int remainder;
 823
 824        if (!(s->flags & SLAB_POISON))
 825                return 1;
 826
 827        start = page_address(page);
 828        length = (PAGE_SIZE << compound_order(page)) - s->reserved;
 829        end = start + length;
 830        remainder = length % s->size;
 831        if (!remainder)
 832                return 1;
 833
 834        fault = check_bytes(end - remainder, POISON_INUSE, remainder);
 835        if (!fault)
 836                return 1;
 837        while (end > fault && end[-1] == POISON_INUSE)
 838                end--;
 839
 840        slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
 841        print_section("Padding", end - remainder, remainder);
 842
 843        restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
 844        return 0;
 845}
 846
 847static int check_object(struct kmem_cache *s, struct page *page,
 848                                        void *object, u8 val)
 849{
 850        u8 *p = object;
 851        u8 *endobject = object + s->objsize;
 852
 853        if (s->flags & SLAB_RED_ZONE) {
 854                if (!check_bytes_and_report(s, page, object, "Redzone",
 855                        endobject, val, s->inuse - s->objsize))
 856                        return 0;
 857        } else {
 858                if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
 859                        check_bytes_and_report(s, page, p, "Alignment padding",
 860                                endobject, POISON_INUSE, s->inuse - s->objsize);
 861                }
 862        }
 863
 864        if (s->flags & SLAB_POISON) {
 865                if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
 866                        (!check_bytes_and_report(s, page, p, "Poison", p,
 867                                        POISON_FREE, s->objsize - 1) ||
 868                         !check_bytes_and_report(s, page, p, "Poison",
 869                                p + s->objsize - 1, POISON_END, 1)))
 870                        return 0;
 871                /*
 872                 * check_pad_bytes cleans up on its own.
 873                 */
 874                check_pad_bytes(s, page, p);
 875        }
 876
 877        if (!s->offset && val == SLUB_RED_ACTIVE)
 878                /*
 879                 * Object and freepointer overlap. Cannot check
 880                 * freepointer while object is allocated.
 881                 */
 882                return 1;
 883
 884        /* Check free pointer validity */
 885        if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
 886                object_err(s, page, p, "Freepointer corrupt");
 887                /*
 888                 * No choice but to zap it and thus lose the remainder
 889                 * of the free objects in this slab. May cause
 890                 * another error because the object count is now wrong.
 891                 */
 892                set_freepointer(s, p, NULL);
 893                return 0;
 894        }
 895        return 1;
 896}
 897
 898static int check_slab(struct kmem_cache *s, struct page *page)
 899{
 900        int maxobj;
 901
 902        VM_BUG_ON(!irqs_disabled());
 903
 904        if (!PageSlab(page)) {
 905                slab_err(s, page, "Not a valid slab page");
 906                return 0;
 907        }
 908
 909        maxobj = order_objects(compound_order(page), s->size, s->reserved);
 910        if (page->objects > maxobj) {
 911                slab_err(s, page, "objects %u > max %u",
 912                        s->name, page->objects, maxobj);
 913                return 0;
 914        }
 915        if (page->inuse > page->objects) {
 916                slab_err(s, page, "inuse %u > max %u",
 917                        s->name, page->inuse, page->objects);
 918                return 0;
 919        }
 920        /* Slab_pad_check fixes things up after itself */
 921        slab_pad_check(s, page);
 922        return 1;
 923}
 924
 925/*
 926 * Determine if a certain object on a page is on the freelist. Must hold the
 927 * slab lock to guarantee that the chains are in a consistent state.
 928 */
 929static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
 930{
 931        int nr = 0;
 932        void *fp;
 933        void *object = NULL;
 934        unsigned long max_objects;
 935
 936        fp = page->freelist;
 937        while (fp && nr <= page->objects) {
 938                if (fp == search)
 939                        return 1;
 940                if (!check_valid_pointer(s, page, fp)) {
 941                        if (object) {
 942                                object_err(s, page, object,
 943                                        "Freechain corrupt");
 944                                set_freepointer(s, object, NULL);
 945                                break;
 946                        } else {
 947                                slab_err(s, page, "Freepointer corrupt");
 948                                page->freelist = NULL;
 949                                page->inuse = page->objects;
 950                                slab_fix(s, "Freelist cleared");
 951                                return 0;
 952                        }
 953                        break;
 954                }
 955                object = fp;
 956                fp = get_freepointer(s, object);
 957                nr++;
 958        }
 959
 960        max_objects = order_objects(compound_order(page), s->size, s->reserved);
 961        if (max_objects > MAX_OBJS_PER_PAGE)
 962                max_objects = MAX_OBJS_PER_PAGE;
 963
 964        if (page->objects != max_objects) {
 965                slab_err(s, page, "Wrong number of objects. Found %d but "
 966                        "should be %d", page->objects, max_objects);
 967                page->objects = max_objects;
 968                slab_fix(s, "Number of objects adjusted.");
 969        }
 970        if (page->inuse != page->objects - nr) {
 971                slab_err(s, page, "Wrong object count. Counter is %d but "
 972                        "counted were %d", page->inuse, page->objects - nr);
 973                page->inuse = page->objects - nr;
 974                slab_fix(s, "Object count adjusted.");
 975        }
 976        return search == NULL;
 977}
 978
 979static void trace(struct kmem_cache *s, struct page *page, void *object,
 980                                                                int alloc)
 981{
 982        if (s->flags & SLAB_TRACE) {
 983                printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
 984                        s->name,
 985                        alloc ? "alloc" : "free",
 986                        object, page->inuse,
 987                        page->freelist);
 988
 989                if (!alloc)
 990                        print_section("Object", (void *)object, s->objsize);
 991
 992                dump_stack();
 993        }
 994}
 995
 996/*
 997 * Hooks for other subsystems that check memory allocations. In a typical
 998 * production configuration these hooks all should produce no code at all.
 999 */
1000static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1001{
1002        flags &= gfp_allowed_mask;
1003        lockdep_trace_alloc(flags);
1004        might_sleep_if(flags & __GFP_WAIT);
1005
1006        return should_failslab(s->objsize, flags, s->flags);
1007}
1008
1009static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
1010{
1011        flags &= gfp_allowed_mask;
1012        kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
1013        kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
1014}
1015
1016static inline void slab_free_hook(struct kmem_cache *s, void *x)
1017{
1018        kmemleak_free_recursive(x, s->flags);
1019
1020        /*
1021         * Trouble is that we may no longer disable interupts in the fast path
1022         * So in order to make the debug calls that expect irqs to be
1023         * disabled we need to disable interrupts temporarily.
1024         */
1025#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
1026        {
1027                unsigned long flags;
1028
1029                local_irq_save(flags);
1030                kmemcheck_slab_free(s, x, s->objsize);
1031                debug_check_no_locks_freed(x, s->objsize);
1032                local_irq_restore(flags);
1033        }
1034#endif
1035        if (!(s->flags & SLAB_DEBUG_OBJECTS))
1036                debug_check_no_obj_freed(x, s->objsize);
1037}
1038
1039/*
1040 * Tracking of fully allocated slabs for debugging purposes.
1041 *
1042 * list_lock must be held.
1043 */
1044static void add_full(struct kmem_cache *s,
1045        struct kmem_cache_node *n, struct page *page)
1046{
1047        if (!(s->flags & SLAB_STORE_USER))
1048                return;
1049
1050        list_add(&page->lru, &n->full);
1051}
1052
1053/*
1054 * list_lock must be held.
1055 */
1056static void remove_full(struct kmem_cache *s, struct page *page)
1057{
1058        if (!(s->flags & SLAB_STORE_USER))
1059                return;
1060
1061        list_del(&page->lru);
1062}
1063
1064/* Tracking of the number of slabs for debugging purposes */
1065static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1066{
1067        struct kmem_cache_node *n = get_node(s, node);
1068
1069        return atomic_long_read(&n->nr_slabs);
1070}
1071
1072static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1073{
1074        return atomic_long_read(&n->nr_slabs);
1075}
1076
1077static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1078{
1079        struct kmem_cache_node *n = get_node(s, node);
1080
1081        /*
1082         * May be called early in order to allocate a slab for the
1083         * kmem_cache_node structure. Solve the chicken-egg
1084         * dilemma by deferring the increment of the count during
1085         * bootstrap (see early_kmem_cache_node_alloc).
1086         */
1087        if (n) {
1088                atomic_long_inc(&n->nr_slabs);
1089                atomic_long_add(objects, &n->total_objects);
1090        }
1091}
1092static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1093{
1094        struct kmem_cache_node *n = get_node(s, node);
1095
1096        atomic_long_dec(&n->nr_slabs);
1097        atomic_long_sub(objects, &n->total_objects);
1098}
1099
1100/* Object debug checks for alloc/free paths */
1101static void setup_object_debug(struct kmem_cache *s, struct page *page,
1102                                                                void *object)
1103{
1104        if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1105                return;
1106
1107        init_object(s, object, SLUB_RED_INACTIVE);
1108        init_tracking(s, object);
1109}
1110
1111static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
1112                                        void *object, unsigned long addr)
1113{
1114        if (!check_slab(s, page))
1115                goto bad;
1116
1117        if (!check_valid_pointer(s, page, object)) {
1118                object_err(s, page, object, "Freelist Pointer check fails");
1119                goto bad;
1120        }
1121
1122        if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1123                goto bad;
1124
1125        /* Success perform special debug activities for allocs */
1126        if (s->flags & SLAB_STORE_USER)
1127                set_track(s, object, TRACK_ALLOC, addr);
1128        trace(s, page, object, 1);
1129        init_object(s, object, SLUB_RED_ACTIVE);
1130        return 1;
1131
1132bad:
1133        if (PageSlab(page)) {
1134                /*
1135                 * If this is a slab page then lets do the best we can
1136                 * to avoid issues in the future. Marking all objects
1137                 * as used avoids touching the remaining objects.
1138                 */
1139                slab_fix(s, "Marking all objects used");
1140                page->inuse = page->objects;
1141                page->freelist = NULL;
1142        }
1143        return 0;
1144}
1145
1146static noinline int free_debug_processing(struct kmem_cache *s,
1147                 struct page *page, void *object, unsigned long addr)
1148{
1149        unsigned long flags;
1150        int rc = 0;
1151
1152        local_irq_save(flags);
1153        slab_lock(page);
1154
1155        if (!check_slab(s, page))
1156                goto fail;
1157
1158        if (!check_valid_pointer(s, page, object)) {
1159                slab_err(s, page, "Invalid object pointer 0x%p", object);
1160                goto fail;
1161        }
1162
1163        if (on_freelist(s, page, object)) {
1164                object_err(s, page, object, "Object already free");
1165                goto fail;
1166        }
1167
1168        if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1169                goto out;
1170
1171        if (unlikely(s != page->slab)) {
1172                if (!PageSlab(page)) {
1173                        slab_err(s, page, "Attempt to free object(0x%p) "
1174                                "outside of slab", object);
1175                } else if (!page->slab) {
1176                        printk(KERN_ERR
1177                                "SLUB <none>: no slab for object 0x%p.\n",
1178                                                object);
1179                        dump_stack();
1180                } else
1181                        object_err(s, page, object,
1182                                        "page slab pointer corrupt.");
1183                goto fail;
1184        }
1185
1186        if (s->flags & SLAB_STORE_USER)
1187                set_track(s, object, TRACK_FREE, addr);
1188        trace(s, page, object, 0);
1189        init_object(s, object, SLUB_RED_INACTIVE);
1190        rc = 1;
1191out:
1192        slab_unlock(page);
1193        local_irq_restore(flags);
1194        return rc;
1195
1196fail:
1197        slab_fix(s, "Object at 0x%p not freed", object);
1198        goto out;
1199}
1200
1201static int __init setup_slub_debug(char *str)
1202{
1203        slub_debug = DEBUG_DEFAULT_FLAGS;
1204        if (*str++ != '=' || !*str)
1205                /*
1206                 * No options specified. Switch on full debugging.
1207                 */
1208                goto out;
1209
1210        if (*str == ',')
1211                /*
1212                 * No options but restriction on slabs. This means full
1213                 * debugging for slabs matching a pattern.
1214                 */
1215                goto check_slabs;
1216
1217        if (tolower(*str) == 'o') {
1218                /*
1219                 * Avoid enabling debugging on caches if its minimum order
1220                 * would increase as a result.
1221                 */
1222                disable_higher_order_debug = 1;
1223                goto out;
1224        }
1225
1226        slub_debug = 0;
1227        if (*str == '-')
1228                /*
1229                 * Switch off all debugging measures.
1230                 */
1231                goto out;
1232
1233        /*
1234         * Determine which debug features should be switched on
1235         */
1236        for (; *str && *str != ','; str++) {
1237                switch (tolower(*str)) {
1238                case 'f':
1239                        slub_debug |= SLAB_DEBUG_FREE;
1240                        break;
1241                case 'z':
1242                        slub_debug |= SLAB_RED_ZONE;
1243                        break;
1244                case 'p':
1245                        slub_debug |= SLAB_POISON;
1246                        break;
1247                case 'u':
1248                        slub_debug |= SLAB_STORE_USER;
1249                        break;
1250                case 't':
1251                        slub_debug |= SLAB_TRACE;
1252                        break;
1253                case 'a':
1254                        slub_debug |= SLAB_FAILSLAB;
1255                        break;
1256                default:
1257                        printk(KERN_ERR "slub_debug option '%c' "
1258                                "unknown. skipped\n", *str);
1259                }
1260        }
1261
1262check_slabs:
1263        if (*str == ',')
1264                slub_debug_slabs = str + 1;
1265out:
1266        return 1;
1267}
1268
1269__setup("slub_debug", setup_slub_debug);
1270
1271static unsigned long kmem_cache_flags(unsigned long objsize,
1272        unsigned long flags, const char *name,
1273        void (*ctor)(void *))
1274{
1275        /*
1276         * Enable debugging if selected on the kernel commandline.
1277         */
1278        if (slub_debug && (!slub_debug_slabs ||
1279                !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
1280                flags |= slub_debug;
1281
1282        return flags;
1283}
1284#else
1285static inline void setup_object_debug(struct kmem_cache *s,
1286                        struct page *page, void *object) {}
1287
1288static inline int alloc_debug_processing(struct kmem_cache *s,
1289        struct page *page, void *object, unsigned long addr) { return 0; }
1290
1291static inline int free_debug_processing(struct kmem_cache *s,
1292        struct page *page, void *object, unsigned long addr) { return 0; }
1293
1294static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1295                        { return 1; }
1296static inline int check_object(struct kmem_cache *s, struct page *page,
1297                        void *object, u8 val) { return 1; }
1298static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1299                                        struct page *page) {}
1300static inline void remove_full(struct kmem_cache *s, struct page *page) {}
1301static inline unsigned long kmem_cache_flags(unsigned long objsize,
1302        unsigned long flags, const char *name,
1303        void (*ctor)(void *))
1304{
1305        return flags;
1306}
1307#define slub_debug 0
1308
1309#define disable_higher_order_debug 0
1310
1311static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1312                                                        { return 0; }
1313static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1314                                                        { return 0; }
1315static inline void inc_slabs_node(struct kmem_cache *s, int node,
1316                                                        int objects) {}
1317static inline void dec_slabs_node(struct kmem_cache *s, int node,
1318                                                        int objects) {}
1319
1320static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1321                                                        { return 0; }
1322
1323static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
1324                void *object) {}
1325
1326static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
1327
1328#endif /* CONFIG_SLUB_DEBUG */
1329
1330/*
1331 * Slab allocation and freeing
1332 */
1333static inline struct page *alloc_slab_page(gfp_t flags, int node,
1334                                        struct kmem_cache_order_objects oo)
1335{
1336        int order = oo_order(oo);
1337
1338        flags |= __GFP_NOTRACK;
1339
1340        if (node == NUMA_NO_NODE)
1341                return alloc_pages(flags, order);
1342        else
1343                return alloc_pages_exact_node(node, flags, order);
1344}
1345
1346static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1347{
1348        struct page *page;
1349        struct kmem_cache_order_objects oo = s->oo;
1350        gfp_t alloc_gfp;
1351
1352        flags &= gfp_allowed_mask;
1353
1354        if (flags & __GFP_WAIT)
1355                local_irq_enable();
1356
1357        flags |= s->allocflags;
1358
1359        /*
1360         * Let the initial higher-order allocation fail under memory pressure
1361         * so we fall-back to the minimum order allocation.
1362         */
1363        alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1364
1365        page = alloc_slab_page(alloc_gfp, node, oo);
1366        if (unlikely(!page)) {
1367                oo = s->min;
1368                /*
1369                 * Allocation may have failed due to fragmentation.
1370                 * Try a lower order alloc if possible
1371                 */
1372                page = alloc_slab_page(flags, node, oo);
1373
1374                if (page)
1375                        stat(s, ORDER_FALLBACK);
1376        }
1377
1378        if (flags & __GFP_WAIT)
1379                local_irq_disable();
1380
1381        if (!page)
1382                return NULL;
1383
1384        if (kmemcheck_enabled
1385                && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1386                int pages = 1 << oo_order(oo);
1387
1388                kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
1389
1390                /*
1391                 * Objects from caches that have a constructor don't get
1392                 * cleared when they're allocated, so we need to do it here.
1393                 */
1394                if (s->ctor)
1395                        kmemcheck_mark_uninitialized_pages(page, pages);
1396                else
1397                        kmemcheck_mark_unallocated_pages(page, pages);
1398        }
1399
1400        page->objects = oo_objects(oo);
1401        mod_zone_page_state(page_zone(page),
1402                (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1403                NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1404                1 << oo_order(oo));
1405
1406        return page;
1407}
1408
1409static void setup_object(struct kmem_cache *s, struct page *page,
1410                                void *object)
1411{
1412        setup_object_debug(s, page, object);
1413        if (unlikely(s->ctor))
1414                s->ctor(object);
1415}
1416
1417static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1418{
1419        struct page *page;
1420        void *start;
1421        void *last;
1422        void *p;
1423
1424        BUG_ON(flags & GFP_SLAB_BUG_MASK);
1425
1426        page = allocate_slab(s,
1427                flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1428        if (!page)
1429                goto out;
1430
1431        inc_slabs_node(s, page_to_nid(page), page->objects);
1432        page->slab = s;
1433        page->flags |= 1 << PG_slab;
1434
1435        start = page_address(page);
1436
1437        if (unlikely(s->flags & SLAB_POISON))
1438                memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
1439
1440        last = start;
1441        for_each_object(p, s, start, page->objects) {
1442                setup_object(s, page, last);
1443                set_freepointer(s, last, p);
1444                last = p;
1445        }
1446        setup_object(s, page, last);
1447        set_freepointer(s, last, NULL);
1448
1449        page->freelist = start;
1450        page->inuse = 0;
1451        page->frozen = 1;
1452out:
1453        return page;
1454}
1455
1456static void __free_slab(struct kmem_cache *s, struct page *page)
1457{
1458        int order = compound_order(page);
1459        int pages = 1 << order;
1460
1461        if (kmem_cache_debug(s)) {
1462                void *p;
1463
1464                slab_pad_check(s, page);
1465                for_each_object(p, s, page_address(page),
1466                                                page->objects)
1467                        check_object(s, page, p, SLUB_RED_INACTIVE);
1468        }
1469
1470        kmemcheck_free_shadow(page, compound_order(page));
1471
1472        mod_zone_page_state(page_zone(page),
1473                (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1474                NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1475                -pages);
1476
1477        __ClearPageSlab(page);
1478        reset_page_mapcount(page);
1479        if (current->reclaim_state)
1480                current->reclaim_state->reclaimed_slab += pages;
1481        __free_pages(page, order);
1482}
1483
1484#define need_reserve_slab_rcu                                           \
1485        (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1486
1487static void rcu_free_slab(struct rcu_head *h)
1488{
1489        struct page *page;
1490
1491        if (need_reserve_slab_rcu)
1492                page = virt_to_head_page(h);
1493        else
1494                page = container_of((struct list_head *)h, struct page, lru);
1495
1496        __free_slab(page->slab, page);
1497}
1498
1499static void free_slab(struct kmem_cache *s, struct page *page)
1500{
1501        if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1502                struct rcu_head *head;
1503
1504                if (need_reserve_slab_rcu) {
1505                        int order = compound_order(page);
1506                        int offset = (PAGE_SIZE << order) - s->reserved;
1507
1508                        VM_BUG_ON(s->reserved != sizeof(*head));
1509                        head = page_address(page) + offset;
1510                } else {
1511                        /*
1512                         * RCU free overloads the RCU head over the LRU
1513                         */
1514                        head = (void *)&page->lru;
1515                }
1516
1517                call_rcu(head, rcu_free_slab);
1518        } else
1519                __free_slab(s, page);
1520}
1521
1522static void discard_slab(struct kmem_cache *s, struct page *page)
1523{
1524        dec_slabs_node(s, page_to_nid(page), page->objects);
1525        free_slab(s, page);
1526}
1527
1528/*
1529 * Management of partially allocated slabs.
1530 *
1531 * list_lock must be held.
1532 */
1533static inline void add_partial(struct kmem_cache_node *n,
1534                                struct page *page, int tail)
1535{
1536        n->nr_partial++;
1537        if (tail)
1538                list_add_tail(&page->lru, &n->partial);
1539        else
1540                list_add(&page->lru, &n->partial);
1541}
1542
1543/*
1544 * list_lock must be held.
1545 */
1546static inline void remove_partial(struct kmem_cache_node *n,
1547                                        struct page *page)
1548{
1549        list_del(&page->lru);
1550        n->nr_partial--;
1551}
1552
1553/*
1554 * Lock slab, remove from the partial list and put the object into the
1555 * per cpu freelist.
1556 *
1557 * Must hold list_lock.
1558 */
1559static inline int acquire_slab(struct kmem_cache *s,
1560                struct kmem_cache_node *n, struct page *page)
1561{
1562        void *freelist;
1563        unsigned long counters;
1564        struct page new;
1565
1566        /*
1567         * Zap the freelist and set the frozen bit.
1568         * The old freelist is the list of objects for the
1569         * per cpu allocation list.
1570         */
1571        do {
1572                freelist = page->freelist;
1573                counters = page->counters;
1574                new.counters = counters;
1575                new.inuse = page->objects;
1576
1577                VM_BUG_ON(new.frozen);
1578                new.frozen = 1;
1579
1580        } while (!__cmpxchg_double_slab(s, page,
1581                        freelist, counters,
1582                        NULL, new.counters,
1583                        "lock and freeze"));
1584
1585        remove_partial(n, page);
1586
1587        if (freelist) {
1588                /* Populate the per cpu freelist */
1589                this_cpu_write(s->cpu_slab->freelist, freelist);
1590                this_cpu_write(s->cpu_slab->page, page);
1591                this_cpu_write(s->cpu_slab->node, page_to_nid(page));
1592                return 1;
1593        } else {
1594                /*
1595                 * Slab page came from the wrong list. No object to allocate
1596                 * from. Put it onto the correct list and continue partial
1597                 * scan.
1598                 */
1599                printk(KERN_ERR "SLUB: %s : Page without available objects on"
1600                        " partial list\n", s->name);
1601                return 0;
1602        }
1603}
1604
1605/*
1606 * Try to allocate a partial slab from a specific node.
1607 */
1608static struct page *get_partial_node(struct kmem_cache *s,
1609                                        struct kmem_cache_node *n)
1610{
1611        struct page *page;
1612
1613        /*
1614         * Racy check. If we mistakenly see no partial slabs then we
1615         * just allocate an empty slab. If we mistakenly try to get a
1616         * partial slab and there is none available then get_partials()
1617         * will return NULL.
1618         */
1619        if (!n || !n->nr_partial)
1620                return NULL;
1621
1622        spin_lock(&n->list_lock);
1623        list_for_each_entry(page, &n->partial, lru)
1624                if (acquire_slab(s, n, page))
1625                        goto out;
1626        page = NULL;
1627out:
1628        spin_unlock(&n->list_lock);
1629        return page;
1630}
1631
1632/*
1633 * Get a page from somewhere. Search in increasing NUMA distances.
1634 */
1635static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
1636{
1637#ifdef CONFIG_NUMA
1638        struct zonelist *zonelist;
1639        struct zoneref *z;
1640        struct zone *zone;
1641        enum zone_type high_zoneidx = gfp_zone(flags);
1642        struct page *page;
1643
1644        /*
1645         * The defrag ratio allows a configuration of the tradeoffs between
1646         * inter node defragmentation and node local allocations. A lower
1647         * defrag_ratio increases the tendency to do local allocations
1648         * instead of attempting to obtain partial slabs from other nodes.
1649         *
1650         * If the defrag_ratio is set to 0 then kmalloc() always
1651         * returns node local objects. If the ratio is higher then kmalloc()
1652         * may return off node objects because partial slabs are obtained
1653         * from other nodes and filled up.
1654         *
1655         * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1656         * defrag_ratio = 1000) then every (well almost) allocation will
1657         * first attempt to defrag slab caches on other nodes. This means
1658         * scanning over all nodes to look for partial slabs which may be
1659         * expensive if we do it every time we are trying to find a slab
1660         * with available objects.
1661         */
1662        if (!s->remote_node_defrag_ratio ||
1663                        get_cycles() % 1024 > s->remote_node_defrag_ratio)
1664                return NULL;
1665
1666        get_mems_allowed();
1667        zonelist = node_zonelist(slab_node(current->mempolicy), flags);
1668        for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1669                struct kmem_cache_node *n;
1670
1671                n = get_node(s, zone_to_nid(zone));
1672
1673                if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1674                                n->nr_partial > s->min_partial) {
1675                        page = get_partial_node(s, n);
1676                        if (page) {
1677                                put_mems_allowed();
1678                                return page;
1679                        }
1680                }
1681        }
1682        put_mems_allowed();
1683#endif
1684        return NULL;
1685}
1686
1687/*
1688 * Get a partial page, lock it and return it.
1689 */
1690static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
1691{
1692        struct page *page;
1693        int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
1694
1695        page = get_partial_node(s, get_node(s, searchnode));
1696        if (page || node != NUMA_NO_NODE)
1697                return page;
1698
1699        return get_any_partial(s, flags);
1700}
1701
1702#ifdef CONFIG_PREEMPT
1703/*
1704 * Calculate the next globally unique transaction for disambiguiation
1705 * during cmpxchg. The transactions start with the cpu number and are then
1706 * incremented by CONFIG_NR_CPUS.
1707 */
1708#define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
1709#else
1710/*
1711 * No preemption supported therefore also no need to check for
1712 * different cpus.
1713 */
1714#define TID_STEP 1
1715#endif
1716
1717static inline unsigned long next_tid(unsigned long tid)
1718{
1719        return tid + TID_STEP;
1720}
1721
1722static inline unsigned int tid_to_cpu(unsigned long tid)
1723{
1724        return tid % TID_STEP;
1725}
1726
1727static inline unsigned long tid_to_event(unsigned long tid)
1728{
1729        return tid / TID_STEP;
1730}
1731
1732static inline unsigned int init_tid(int cpu)
1733{
1734        return cpu;
1735}
1736
1737static inline void note_cmpxchg_failure(const char *n,
1738                const struct kmem_cache *s, unsigned long tid)
1739{
1740#ifdef SLUB_DEBUG_CMPXCHG
1741        unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1742
1743        printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
1744
1745#ifdef CONFIG_PREEMPT
1746        if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1747                printk("due to cpu change %d -> %d\n",
1748                        tid_to_cpu(tid), tid_to_cpu(actual_tid));
1749        else
1750#endif
1751        if (tid_to_event(tid) != tid_to_event(actual_tid))
1752                printk("due to cpu running other code. Event %ld->%ld\n",
1753                        tid_to_event(tid), tid_to_event(actual_tid));
1754        else
1755                printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1756                        actual_tid, tid, next_tid(tid));
1757#endif
1758        stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1759}
1760
1761void init_kmem_cache_cpus(struct kmem_cache *s)
1762{
1763        int cpu;
1764
1765        for_each_possible_cpu(cpu)
1766                per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1767}
1768/*
1769 * Remove the cpu slab
1770 */
1771
1772/*
1773 * Remove the cpu slab
1774 */
1775static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1776{
1777        enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1778        struct page *page = c->page;
1779        struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1780        int lock = 0;
1781        enum slab_modes l = M_NONE, m = M_NONE;
1782        void *freelist;
1783        void *nextfree;
1784        int tail = 0;
1785        struct page new;
1786        struct page old;
1787
1788        if (page->freelist) {
1789                stat(s, DEACTIVATE_REMOTE_FREES);
1790                tail = 1;
1791        }
1792
1793        c->tid = next_tid(c->tid);
1794        c->page = NULL;
1795        freelist = c->freelist;
1796        c->freelist = NULL;
1797
1798        /*
1799         * Stage one: Free all available per cpu objects back
1800         * to the page freelist while it is still frozen. Leave the
1801         * last one.
1802         *
1803         * There is no need to take the list->lock because the page
1804         * is still frozen.
1805         */
1806        while (freelist && (nextfree = get_freepointer(s, freelist))) {
1807                void *prior;
1808                unsigned long counters;
1809
1810                do {
1811                        prior = page->freelist;
1812                        counters = page->counters;
1813                        set_freepointer(s, freelist, prior);
1814                        new.counters = counters;
1815                        new.inuse--;
1816                        VM_BUG_ON(!new.frozen);
1817
1818                } while (!__cmpxchg_double_slab(s, page,
1819                        prior, counters,
1820                        freelist, new.counters,
1821                        "drain percpu freelist"));
1822
1823                freelist = nextfree;
1824        }
1825
1826        /*
1827         * Stage two: Ensure that the page is unfrozen while the
1828         * list presence reflects the actual number of objects
1829         * during unfreeze.
1830         *
1831         * We setup the list membership and then perform a cmpxchg
1832         * with the count. If there is a mismatch then the page
1833         * is not unfrozen but the page is on the wrong list.
1834         *
1835         * Then we restart the process which may have to remove
1836         * the page from the list that we just put it on again
1837         * because the number of objects in the slab may have
1838         * changed.
1839         */
1840redo:
1841
1842        old.freelist = page->freelist;
1843        old.counters = page->counters;
1844        VM_BUG_ON(!old.frozen);
1845
1846        /* Determine target state of the slab */
1847        new.counters = old.counters;
1848        if (freelist) {
1849                new.inuse--;
1850                set_freepointer(s, freelist, old.freelist);
1851                new.freelist = freelist;
1852        } else
1853                new.freelist = old.freelist;
1854
1855        new.frozen = 0;
1856
1857        if (!new.inuse && n->nr_partial > s->min_partial)
1858                m = M_FREE;
1859        else if (new.freelist) {
1860                m = M_PARTIAL;
1861                if (!lock) {
1862                        lock = 1;
1863                        /*
1864                         * Taking the spinlock removes the possiblity
1865                         * that acquire_slab() will see a slab page that
1866                         * is frozen
1867                         */
1868                        spin_lock(&n->list_lock);
1869                }
1870        } else {
1871                m = M_FULL;
1872                if (kmem_cache_debug(s) && !lock) {
1873                        lock = 1;
1874                        /*
1875                         * This also ensures that the scanning of full
1876                         * slabs from diagnostic functions will not see
1877                         * any frozen slabs.
1878                         */
1879                        spin_lock(&n->list_lock);
1880                }
1881        }
1882
1883        if (l != m) {
1884
1885                if (l == M_PARTIAL)
1886
1887                        remove_partial(n, page);
1888
1889                else if (l == M_FULL)
1890
1891                        remove_full(s, page);
1892
1893                if (m == M_PARTIAL) {
1894
1895                        add_partial(n, page, tail);
1896                        stat(s, tail ? DEACTIVATE_TO_TAIL : DEACTIVATE_TO_HEAD);
1897
1898                } else if (m == M_FULL) {
1899
1900                        stat(s, DEACTIVATE_FULL);
1901                        add_full(s, n, page);
1902
1903                }
1904        }
1905
1906        l = m;
1907        if (!__cmpxchg_double_slab(s, page,
1908                                old.freelist, old.counters,
1909                                new.freelist, new.counters,
1910                                "unfreezing slab"))
1911                goto redo;
1912
1913        if (lock)
1914                spin_unlock(&n->list_lock);
1915
1916        if (m == M_FREE) {
1917                stat(s, DEACTIVATE_EMPTY);
1918                discard_slab(s, page);
1919                stat(s, FREE_SLAB);
1920        }
1921}
1922
1923static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1924{
1925        stat(s, CPUSLAB_FLUSH);
1926        deactivate_slab(s, c);
1927}
1928
1929/*
1930 * Flush cpu slab.
1931 *
1932 * Called from IPI handler with interrupts disabled.
1933 */
1934static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
1935{
1936        struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
1937
1938        if (likely(c && c->page))
1939                flush_slab(s, c);
1940}
1941
1942static void flush_cpu_slab(void *d)
1943{
1944        struct kmem_cache *s = d;
1945
1946        __flush_cpu_slab(s, smp_processor_id());
1947}
1948
1949static void flush_all(struct kmem_cache *s)
1950{
1951        on_each_cpu(flush_cpu_slab, s, 1);
1952}
1953
1954/*
1955 * Check if the objects in a per cpu structure fit numa
1956 * locality expectations.
1957 */
1958static inline int node_match(struct kmem_cache_cpu *c, int node)
1959{
1960#ifdef CONFIG_NUMA
1961        if (node != NUMA_NO_NODE && c->node != node)
1962                return 0;
1963#endif
1964        return 1;
1965}
1966
1967static int count_free(struct page *page)
1968{
1969        return page->objects - page->inuse;
1970}
1971
1972static unsigned long count_partial(struct kmem_cache_node *n,
1973                                        int (*get_count)(struct page *))
1974{
1975        unsigned long flags;
1976        unsigned long x = 0;
1977        struct page *page;
1978
1979        spin_lock_irqsave(&n->list_lock, flags);
1980        list_for_each_entry(page, &n->partial, lru)
1981                x += get_count(page);
1982        spin_unlock_irqrestore(&n->list_lock, flags);
1983        return x;
1984}
1985
1986static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
1987{
1988#ifdef CONFIG_SLUB_DEBUG
1989        return atomic_long_read(&n->total_objects);
1990#else
1991        return 0;
1992#endif
1993}
1994
1995static noinline void
1996slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
1997{
1998        int node;
1999
2000        printk(KERN_WARNING
2001                "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2002                nid, gfpflags);
2003        printk(KERN_WARNING "  cache: %s, object size: %d, buffer size: %d, "
2004                "default order: %d, min order: %d\n", s->name, s->objsize,
2005                s->size, oo_order(s->oo), oo_order(s->min));
2006
2007        if (oo_order(s->min) > get_order(s->objsize))
2008                printk(KERN_WARNING "  %s debugging increased min order, use "
2009                       "slub_debug=O to disable.\n", s->name);
2010
2011        for_each_online_node(node) {
2012                struct kmem_cache_node *n = get_node(s, node);
2013                unsigned long nr_slabs;
2014                unsigned long nr_objs;
2015                unsigned long nr_free;
2016
2017                if (!n)
2018                        continue;
2019
2020                nr_free  = count_partial(n, count_free);
2021                nr_slabs = node_nr_slabs(n);
2022                nr_objs  = node_nr_objs(n);
2023
2024                printk(KERN_WARNING
2025                        "  node %d: slabs: %ld, objs: %ld, free: %ld\n",
2026                        node, nr_slabs, nr_objs, nr_free);
2027        }
2028}
2029
2030/*
2031 * Slow path. The lockless freelist is empty or we need to perform
2032 * debugging duties.
2033 *
2034 * Interrupts are disabled.
2035 *
2036 * Processing is still very fast if new objects have been freed to the
2037 * regular freelist. In that case we simply take over the regular freelist
2038 * as the lockless freelist and zap the regular freelist.
2039 *
2040 * If that is not working then we fall back to the partial lists. We take the
2041 * first element of the freelist as the object to allocate now and move the
2042 * rest of the freelist to the lockless freelist.
2043 *
2044 * And if we were unable to get a new slab from the partial slab lists then
2045 * we need to allocate a new slab. This is the slowest path since it involves
2046 * a call to the page allocator and the setup of a new slab.
2047 */
2048static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2049                          unsigned long addr, struct kmem_cache_cpu *c)
2050{
2051        void **object;
2052        struct page *page;
2053        unsigned long flags;
2054        struct page new;
2055        unsigned long counters;
2056
2057        local_irq_save(flags);
2058#ifdef CONFIG_PREEMPT
2059        /*
2060         * We may have been preempted and rescheduled on a different
2061         * cpu before disabling interrupts. Need to reload cpu area
2062         * pointer.
2063         */
2064        c = this_cpu_ptr(s->cpu_slab);
2065#endif
2066
2067        /* We handle __GFP_ZERO in the caller */
2068        gfpflags &= ~__GFP_ZERO;
2069
2070        page = c->page;
2071        if (!page)
2072                goto new_slab;
2073
2074        if (unlikely(!node_match(c, node))) {
2075                stat(s, ALLOC_NODE_MISMATCH);
2076                deactivate_slab(s, c);
2077                goto new_slab;
2078        }
2079
2080        stat(s, ALLOC_SLOWPATH);
2081
2082        do {
2083                object = page->freelist;
2084                counters = page->counters;
2085                new.counters = counters;
2086                VM_BUG_ON(!new.frozen);
2087
2088                /*
2089                 * If there is no object left then we use this loop to
2090                 * deactivate the slab which is simple since no objects
2091                 * are left in the slab and therefore we do not need to
2092                 * put the page back onto the partial list.
2093                 *
2094                 * If there are objects left then we retrieve them
2095                 * and use them to refill the per cpu queue.
2096                */
2097
2098                new.inuse = page->objects;
2099                new.frozen = object != NULL;
2100
2101        } while (!__cmpxchg_double_slab(s, page,
2102                        object, counters,
2103                        NULL, new.counters,
2104                        "__slab_alloc"));
2105
2106        if (unlikely(!object)) {
2107                c->page = NULL;
2108                stat(s, DEACTIVATE_BYPASS);
2109                goto new_slab;
2110        }
2111
2112        stat(s, ALLOC_REFILL);
2113
2114load_freelist:
2115        VM_BUG_ON(!page->frozen);
2116        c->freelist = get_freepointer(s, object);
2117        c->tid = next_tid(c->tid);
2118        local_irq_restore(flags);
2119        return object;
2120
2121new_slab:
2122        page = get_partial(s, gfpflags, node);
2123        if (page) {
2124                stat(s, ALLOC_FROM_PARTIAL);
2125                object = c->freelist;
2126
2127                if (kmem_cache_debug(s))
2128                        goto debug;
2129                goto load_freelist;
2130        }
2131
2132        page = new_slab(s, gfpflags, node);
2133
2134        if (page) {
2135                c = __this_cpu_ptr(s->cpu_slab);
2136                if (c->page)
2137                        flush_slab(s, c);
2138
2139                /*
2140                 * No other reference to the page yet so we can
2141                 * muck around with it freely without cmpxchg
2142                 */
2143                object = page->freelist;
2144                page->freelist = NULL;
2145                page->inuse = page->objects;
2146
2147                stat(s, ALLOC_SLAB);
2148                c->node = page_to_nid(page);
2149                c->page = page;
2150
2151                if (kmem_cache_debug(s))
2152                        goto debug;
2153                goto load_freelist;
2154        }
2155        if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
2156                slab_out_of_memory(s, gfpflags, node);
2157        local_irq_restore(flags);
2158        return NULL;
2159
2160debug:
2161        if (!object || !alloc_debug_processing(s, page, object, addr))
2162                goto new_slab;
2163
2164        c->freelist = get_freepointer(s, object);
2165        deactivate_slab(s, c);
2166        c->page = NULL;
2167        c->node = NUMA_NO_NODE;
2168        local_irq_restore(flags);
2169        return object;
2170}
2171
2172/*
2173 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2174 * have the fastpath folded into their functions. So no function call
2175 * overhead for requests that can be satisfied on the fastpath.
2176 *
2177 * The fastpath works by first checking if the lockless freelist can be used.
2178 * If not then __slab_alloc is called for slow processing.
2179 *
2180 * Otherwise we can simply pick the next object from the lockless free list.
2181 */
2182static __always_inline void *slab_alloc(struct kmem_cache *s,
2183                gfp_t gfpflags, int node, unsigned long addr)
2184{
2185        void **object;
2186        struct kmem_cache_cpu *c;
2187        unsigned long tid;
2188
2189        if (slab_pre_alloc_hook(s, gfpflags))
2190                return NULL;
2191
2192redo:
2193
2194        /*
2195         * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2196         * enabled. We may switch back and forth between cpus while
2197         * reading from one cpu area. That does not matter as long
2198         * as we end up on the original cpu again when doing the cmpxchg.
2199         */
2200        c = __this_cpu_ptr(s->cpu_slab);
2201
2202        /*
2203         * The transaction ids are globally unique per cpu and per operation on
2204         * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2205         * occurs on the right processor and that there was no operation on the
2206         * linked list in between.
2207         */
2208        tid = c->tid;
2209        barrier();
2210
2211        object = c->freelist;
2212        if (unlikely(!object || !node_match(c, node)))
2213
2214                object = __slab_alloc(s, gfpflags, node, addr, c);
2215
2216        else {
2217                /*
2218                 * The cmpxchg will only match if there was no additional
2219                 * operation and if we are on the right processor.
2220                 *
2221                 * The cmpxchg does the following atomically (without lock semantics!)
2222                 * 1. Relocate first pointer to the current per cpu area.
2223                 * 2. Verify that tid and freelist have not been changed
2224                 * 3. If they were not changed replace tid and freelist
2225                 *
2226                 * Since this is without lock semantics the protection is only against
2227                 * code executing on this cpu *not* from access by other cpus.
2228                 */
2229                if (unlikely(!irqsafe_cpu_cmpxchg_double(
2230                                s->cpu_slab->freelist, s->cpu_slab->tid,
2231                                object, tid,
2232                                get_freepointer_safe(s, object), next_tid(tid)))) {
2233
2234                        note_cmpxchg_failure("slab_alloc", s, tid);
2235                        goto redo;
2236                }
2237                stat(s, ALLOC_FASTPATH);
2238        }
2239
2240        if (unlikely(gfpflags & __GFP_ZERO) && object)
2241                memset(object, 0, s->objsize);
2242
2243        slab_post_alloc_hook(s, gfpflags, object);
2244
2245        return object;
2246}
2247
2248void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2249{
2250        void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
2251
2252        trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
2253
2254        return ret;
2255}
2256EXPORT_SYMBOL(kmem_cache_alloc);
2257
2258#ifdef CONFIG_TRACING
2259void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2260{
2261        void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
2262        trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2263        return ret;
2264}
2265EXPORT_SYMBOL(kmem_cache_alloc_trace);
2266
2267void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
2268{
2269        void *ret = kmalloc_order(size, flags, order);
2270        trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
2271        return ret;
2272}
2273EXPORT_SYMBOL(kmalloc_order_trace);
2274#endif
2275
2276#ifdef CONFIG_NUMA
2277void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2278{
2279        void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
2280
2281        trace_kmem_cache_alloc_node(_RET_IP_, ret,
2282                                    s->objsize, s->size, gfpflags, node);
2283
2284        return ret;
2285}
2286EXPORT_SYMBOL(kmem_cache_alloc_node);
2287
2288#ifdef CONFIG_TRACING
2289void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2290                                    gfp_t gfpflags,
2291                                    int node, size_t size)
2292{
2293        void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
2294
2295        trace_kmalloc_node(_RET_IP_, ret,
2296                           size, s->size, gfpflags, node);
2297        return ret;
2298}
2299EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2300#endif
2301#endif
2302
2303/*
2304 * Slow patch handling. This may still be called frequently since objects
2305 * have a longer lifetime than the cpu slabs in most processing loads.
2306 *
2307 * So we still attempt to reduce cache line usage. Just take the slab
2308 * lock and free the item. If there is no additional partial page
2309 * handling required then we can return immediately.
2310 */
2311static void __slab_free(struct kmem_cache *s, struct page *page,
2312                        void *x, unsigned long addr)
2313{
2314        void *prior;
2315        void **object = (void *)x;
2316        int was_frozen;
2317        int inuse;
2318        struct page new;
2319        unsigned long counters;
2320        struct kmem_cache_node *n = NULL;
2321        unsigned long uninitialized_var(flags);
2322
2323        stat(s, FREE_SLOWPATH);
2324
2325        if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr))
2326                return;
2327
2328        do {
2329                prior = page->freelist;
2330                counters = page->counters;
2331                set_freepointer(s, object, prior);
2332                new.counters = counters;
2333                was_frozen = new.frozen;
2334                new.inuse--;
2335                if ((!new.inuse || !prior) && !was_frozen && !n) {
2336                        n = get_node(s, page_to_nid(page));
2337                        /*
2338                         * Speculatively acquire the list_lock.
2339                         * If the cmpxchg does not succeed then we may
2340                         * drop the list_lock without any processing.
2341                         *
2342                         * Otherwise the list_lock will synchronize with
2343                         * other processors updating the list of slabs.
2344                         */
2345                        spin_lock_irqsave(&n->list_lock, flags);
2346                }
2347                inuse = new.inuse;
2348
2349        } while (!cmpxchg_double_slab(s, page,
2350                prior, counters,
2351                object, new.counters,
2352                "__slab_free"));
2353
2354        if (likely(!n)) {
2355                /*
2356                 * The list lock was not taken therefore no list
2357                 * activity can be necessary.
2358                 */
2359                if (was_frozen)
2360                        stat(s, FREE_FROZEN);
2361                return;
2362        }
2363
2364        /*
2365         * was_frozen may have been set after we acquired the list_lock in
2366         * an earlier loop. So we need to check it here again.
2367         */
2368        if (was_frozen)
2369                stat(s, FREE_FROZEN);
2370        else {
2371                if (unlikely(!inuse && n->nr_partial > s->min_partial))
2372                        goto slab_empty;
2373
2374                /*
2375                 * Objects left in the slab. If it was not on the partial list before
2376                 * then add it.
2377                 */
2378                if (unlikely(!prior)) {
2379                        remove_full(s, page);
2380                        add_partial(n, page, 1);
2381                        stat(s, FREE_ADD_PARTIAL);
2382                }
2383        }
2384        spin_unlock_irqrestore(&n->list_lock, flags);
2385        return;
2386
2387slab_empty:
2388        if (prior) {
2389                /*
2390                 * Slab on the partial list.
2391                 */
2392                remove_partial(n, page);
2393                stat(s, FREE_REMOVE_PARTIAL);
2394        } else
2395                /* Slab must be on the full list */
2396                remove_full(s, page);
2397
2398        spin_unlock_irqrestore(&n->list_lock, flags);
2399        stat(s, FREE_SLAB);
2400        discard_slab(s, page);
2401}
2402
2403/*
2404 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2405 * can perform fastpath freeing without additional function calls.
2406 *
2407 * The fastpath is only possible if we are freeing to the current cpu slab
2408 * of this processor. This typically the case if we have just allocated
2409 * the item before.
2410 *
2411 * If fastpath is not possible then fall back to __slab_free where we deal
2412 * with all sorts of special processing.
2413 */
2414static __always_inline void slab_free(struct kmem_cache *s,
2415                        struct page *page, void *x, unsigned long addr)
2416{
2417        void **object = (void *)x;
2418        struct kmem_cache_cpu *c;
2419        unsigned long tid;
2420
2421        slab_free_hook(s, x);
2422
2423redo:
2424
2425        /*
2426         * Determine the currently cpus per cpu slab.
2427         * The cpu may change afterward. However that does not matter since
2428         * data is retrieved via this pointer. If we are on the same cpu
2429         * during the cmpxchg then the free will succedd.
2430         */
2431        c = __this_cpu_ptr(s->cpu_slab);
2432
2433        tid = c->tid;
2434        barrier();
2435
2436        if (likely(page == c->page)) {
2437                set_freepointer(s, object, c->freelist);
2438
2439                if (unlikely(!irqsafe_cpu_cmpxchg_double(
2440                                s->cpu_slab->freelist, s->cpu_slab->tid,
2441                                c->freelist, tid,
2442                                object, next_tid(tid)))) {
2443
2444                        note_cmpxchg_failure("slab_free", s, tid);
2445                        goto redo;
2446                }
2447                stat(s, FREE_FASTPATH);
2448        } else
2449                __slab_free(s, page, x, addr);
2450
2451}
2452
2453void kmem_cache_free(struct kmem_cache *s, void *x)
2454{
2455        struct page *page;
2456
2457        page = virt_to_head_page(x);
2458
2459        slab_free(s, page, x, _RET_IP_);
2460
2461        trace_kmem_cache_free(_RET_IP_, x);
2462}
2463EXPORT_SYMBOL(kmem_cache_free);
2464
2465/*
2466 * Object placement in a slab is made very easy because we always start at
2467 * offset 0. If we tune the size of the object to the alignment then we can
2468 * get the required alignment by putting one properly sized object after
2469 * another.
2470 *
2471 * Notice that the allocation order determines the sizes of the per cpu
2472 * caches. Each processor has always one slab available for allocations.
2473 * Increasing the allocation order reduces the number of times that slabs
2474 * must be moved on and off the partial lists and is therefore a factor in
2475 * locking overhead.
2476 */
2477
2478/*
2479 * Mininum / Maximum order of slab pages. This influences locking overhead
2480 * and slab fragmentation. A higher order reduces the number of partial slabs
2481 * and increases the number of allocations possible without having to
2482 * take the list_lock.
2483 */
2484static int slub_min_order;
2485static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
2486static int slub_min_objects;
2487
2488/*
2489 * Merge control. If this is set then no merging of slab caches will occur.
2490 * (Could be removed. This was introduced to pacify the merge skeptics.)
2491 */
2492static int slub_nomerge;
2493
2494/*
2495 * Calculate the order of allocation given an slab object size.
2496 *
2497 * The order of allocation has significant impact on performance and other
2498 * system components. Generally order 0 allocations should be preferred since
2499 * order 0 does not cause fragmentation in the page allocator. Larger objects
2500 * be problematic to put into order 0 slabs because there may be too much
2501 * unused space left. We go to a higher order if more than 1/16th of the slab
2502 * would be wasted.
2503 *
2504 * In order to reach satisfactory performance we must ensure that a minimum
2505 * number of objects is in one slab. Otherwise we may generate too much
2506 * activity on the partial lists which requires taking the list_lock. This is
2507 * less a concern for large slabs though which are rarely used.
2508 *
2509 * slub_max_order specifies the order where we begin to stop considering the
2510 * number of objects in a slab as critical. If we reach slub_max_order then
2511 * we try to keep the page order as low as possible. So we accept more waste
2512 * of space in favor of a small page order.
2513 *
2514 * Higher order allocations also allow the placement of more objects in a
2515 * slab and thereby reduce object handling overhead. If the user has
2516 * requested a higher mininum order then we start with that one instead of
2517 * the smallest order which will fit the object.
2518 */
2519static inline int slab_order(int size, int min_objects,
2520                                int max_order, int fract_leftover, int reserved)
2521{
2522        int order;
2523        int rem;
2524        int min_order = slub_min_order;
2525
2526        if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
2527                return get_order(size * MAX_OBJS_PER_PAGE) - 1;
2528
2529        for (order = max(min_order,
2530                                fls(min_objects * size - 1) - PAGE_SHIFT);
2531                        order <= max_order; order++) {
2532
2533                unsigned long slab_size = PAGE_SIZE << order;
2534
2535                if (slab_size < min_objects * size + reserved)
2536                        continue;
2537
2538                rem = (slab_size - reserved) % size;
2539
2540                if (rem <= slab_size / fract_leftover)
2541                        break;
2542
2543        }
2544
2545        return order;
2546}
2547
2548static inline int calculate_order(int size, int reserved)
2549{
2550        int order;
2551        int min_objects;
2552        int fraction;
2553        int max_objects;
2554
2555        /*
2556         * Attempt to find best configuration for a slab. This
2557         * works by first attempting to generate a layout with
2558         * the best configuration and backing off gradually.
2559         *
2560         * First we reduce the acceptable waste in a slab. Then
2561         * we reduce the minimum objects required in a slab.
2562         */
2563        min_objects = slub_min_objects;
2564        if (!min_objects)
2565                min_objects = 4 * (fls(nr_cpu_ids) + 1);
2566        max_objects = order_objects(slub_max_order, size, reserved);
2567        min_objects = min(min_objects, max_objects);
2568
2569        while (min_objects > 1) {
2570                fraction = 16;
2571                while (fraction >= 4) {
2572                        order = slab_order(size, min_objects,
2573                                        slub_max_order, fraction, reserved);
2574                        if (order <= slub_max_order)
2575                                return order;
2576                        fraction /= 2;
2577                }
2578                min_objects--;
2579        }
2580
2581        /*
2582         * We were unable to place multiple objects in a slab. Now
2583         * lets see if we can place a single object there.
2584         */
2585        order = slab_order(size, 1, slub_max_order, 1, reserved);
2586        if (order <= slub_max_order)
2587                return order;
2588
2589        /*
2590         * Doh this slab cannot be placed using slub_max_order.
2591         */
2592        order = slab_order(size, 1, MAX_ORDER, 1, reserved);
2593        if (order < MAX_ORDER)
2594                return order;
2595        return -ENOSYS;
2596}
2597
2598/*
2599 * Figure out what the alignment of the objects will be.
2600 */
2601static unsigned long calculate_alignment(unsigned long flags,
2602                unsigned long align, unsigned long size)
2603{
2604        /*
2605         * If the user wants hardware cache aligned objects then follow that
2606         * suggestion if the object is sufficiently large.
2607         *
2608         * The hardware cache alignment cannot override the specified
2609         * alignment though. If that is greater then use it.
2610         */
2611        if (flags & SLAB_HWCACHE_ALIGN) {
2612                unsigned long ralign = cache_line_size();
2613                while (size <= ralign / 2)
2614                        ralign /= 2;
2615                align = max(align, ralign);
2616        }
2617
2618        if (align < ARCH_SLAB_MINALIGN)
2619                align = ARCH_SLAB_MINALIGN;
2620
2621        return ALIGN(align, sizeof(void *));
2622}
2623
2624static void
2625init_kmem_cache_node(struct kmem_cache_node *n, struct kmem_cache *s)
2626{
2627        n->nr_partial = 0;
2628        spin_lock_init(&n->list_lock);
2629        INIT_LIST_HEAD(&n->partial);
2630#ifdef CONFIG_SLUB_DEBUG
2631        atomic_long_set(&n->nr_slabs, 0);
2632        atomic_long_set(&n->total_objects, 0);
2633        INIT_LIST_HEAD(&n->full);
2634#endif
2635}
2636
2637static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
2638{
2639        BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
2640                        SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
2641
2642        /*
2643         * Must align to double word boundary for the double cmpxchg
2644         * instructions to work; see __pcpu_double_call_return_bool().
2645         */
2646        s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2647                                     2 * sizeof(void *));
2648
2649        if (!s->cpu_slab)
2650                return 0;
2651
2652        init_kmem_cache_cpus(s);
2653
2654        return 1;
2655}
2656
2657static struct kmem_cache *kmem_cache_node;
2658
2659/*
2660 * No kmalloc_node yet so do it by hand. We know that this is the first
2661 * slab on the node for this slabcache. There are no concurrent accesses
2662 * possible.
2663 *
2664 * Note that this function only works on the kmalloc_node_cache
2665 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2666 * memory on a fresh node that has no slab structures yet.
2667 */
2668static void early_kmem_cache_node_alloc(int node)
2669{
2670        struct page *page;
2671        struct kmem_cache_node *n;
2672
2673        BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
2674
2675        page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
2676
2677        BUG_ON(!page);
2678        if (page_to_nid(page) != node) {
2679                printk(KERN_ERR "SLUB: Unable to allocate memory from "
2680                                "node %d\n", node);
2681                printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2682                                "in order to be able to continue\n");
2683        }
2684
2685        n = page->freelist;
2686        BUG_ON(!n);
2687        page->freelist = get_freepointer(kmem_cache_node, n);
2688        page->inuse++;
2689        page->frozen = 0;
2690        kmem_cache_node->node[node] = n;
2691#ifdef CONFIG_SLUB_DEBUG
2692        init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
2693        init_tracking(kmem_cache_node, n);
2694#endif
2695        init_kmem_cache_node(n, kmem_cache_node);
2696        inc_slabs_node(kmem_cache_node, node, page->objects);
2697
2698        add_partial(n, page, 0);
2699}
2700
2701static void free_kmem_cache_nodes(struct kmem_cache *s)
2702{
2703        int node;
2704
2705        for_each_node_state(node, N_NORMAL_MEMORY) {
2706                struct kmem_cache_node *n = s->node[node];
2707
2708                if (n)
2709                        kmem_cache_free(kmem_cache_node, n);
2710
2711                s->node[node] = NULL;
2712        }
2713}
2714
2715static int init_kmem_cache_nodes(struct kmem_cache *s)
2716{
2717        int node;
2718
2719        for_each_node_state(node, N_NORMAL_MEMORY) {
2720                struct kmem_cache_node *n;
2721
2722                if (slab_state == DOWN) {
2723                        early_kmem_cache_node_alloc(node);
2724                        continue;
2725                }
2726                n = kmem_cache_alloc_node(kmem_cache_node,
2727                                                GFP_KERNEL, node);
2728
2729                if (!n) {
2730                        free_kmem_cache_nodes(s);
2731                        return 0;
2732                }
2733
2734                s->node[node] = n;
2735                init_kmem_cache_node(n, s);
2736        }
2737        return 1;
2738}
2739
2740static void set_min_partial(struct kmem_cache *s, unsigned long min)
2741{
2742        if (min < MIN_PARTIAL)
2743                min = MIN_PARTIAL;
2744        else if (min > MAX_PARTIAL)
2745                min = MAX_PARTIAL;
2746        s->min_partial = min;
2747}
2748
2749/*
2750 * calculate_sizes() determines the order and the distribution of data within
2751 * a slab object.
2752 */
2753static int calculate_sizes(struct kmem_cache *s, int forced_order)
2754{
2755        unsigned long flags = s->flags;
2756        unsigned long size = s->objsize;
2757        unsigned long align = s->align;
2758        int order;
2759
2760        /*
2761         * Round up object size to the next word boundary. We can only
2762         * place the free pointer at word boundaries and this determines
2763         * the possible location of the free pointer.
2764         */
2765        size = ALIGN(size, sizeof(void *));
2766
2767#ifdef CONFIG_SLUB_DEBUG
2768        /*
2769         * Determine if we can poison the object itself. If the user of
2770         * the slab may touch the object after free or before allocation
2771         * then we should never poison the object itself.
2772         */
2773        if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2774                        !s->ctor)
2775                s->flags |= __OBJECT_POISON;
2776        else
2777                s->flags &= ~__OBJECT_POISON;
2778
2779
2780        /*
2781         * If we are Redzoning then check if there is some space between the
2782         * end of the object and the free pointer. If not then add an
2783         * additional word to have some bytes to store Redzone information.
2784         */
2785        if ((flags & SLAB_RED_ZONE) && size == s->objsize)
2786                size += sizeof(void *);
2787#endif
2788
2789        /*
2790         * With that we have determined the number of bytes in actual use
2791         * by the object. This is the potential offset to the free pointer.
2792         */
2793        s->inuse = size;
2794
2795        if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2796                s->ctor)) {
2797                /*
2798                 * Relocate free pointer after the object if it is not
2799                 * permitted to overwrite the first word of the object on
2800                 * kmem_cache_free.
2801                 *
2802                 * This is the case if we do RCU, have a constructor or
2803                 * destructor or are poisoning the objects.
2804                 */
2805                s->offset = size;
2806                size += sizeof(void *);
2807        }
2808
2809#ifdef CONFIG_SLUB_DEBUG
2810        if (flags & SLAB_STORE_USER)
2811                /*
2812                 * Need to store information about allocs and frees after
2813                 * the object.
2814                 */
2815                size += 2 * sizeof(struct track);
2816
2817        if (flags & SLAB_RED_ZONE)
2818                /*
2819                 * Add some empty padding so that we can catch
2820                 * overwrites from earlier objects rather than let
2821                 * tracking information or the free pointer be
2822                 * corrupted if a user writes before the start
2823                 * of the object.
2824                 */
2825                size += sizeof(void *);
2826#endif
2827
2828        /*
2829         * Determine the alignment based on various parameters that the
2830         * user specified and the dynamic determination of cache line size
2831         * on bootup.
2832         */
2833        align = calculate_alignment(flags, align, s->objsize);
2834        s->align = align;
2835
2836        /*
2837         * SLUB stores one object immediately after another beginning from
2838         * offset 0. In order to align the objects we have to simply size
2839         * each object to conform to the alignment.
2840         */
2841        size = ALIGN(size, align);
2842        s->size = size;
2843        if (forced_order >= 0)
2844                order = forced_order;
2845        else
2846                order = calculate_order(size, s->reserved);
2847
2848        if (order < 0)
2849                return 0;
2850
2851        s->allocflags = 0;
2852        if (order)
2853                s->allocflags |= __GFP_COMP;
2854
2855        if (s->flags & SLAB_CACHE_DMA)
2856                s->allocflags |= SLUB_DMA;
2857
2858        if (s->flags & SLAB_RECLAIM_ACCOUNT)
2859                s->allocflags |= __GFP_RECLAIMABLE;
2860
2861        /*
2862         * Determine the number of objects per slab
2863         */
2864        s->oo = oo_make(order, size, s->reserved);
2865        s->min = oo_make(get_order(size), size, s->reserved);
2866        if (oo_objects(s->oo) > oo_objects(s->max))
2867                s->max = s->oo;
2868
2869        return !!oo_objects(s->oo);
2870
2871}
2872
2873static int kmem_cache_open(struct kmem_cache *s,
2874                const char *name, size_t size,
2875                size_t align, unsigned long flags,
2876                void (*ctor)(void *))
2877{
2878        memset(s, 0, kmem_size);
2879        s->name = name;
2880        s->ctor = ctor;
2881        s->objsize = size;
2882        s->align = align;
2883        s->flags = kmem_cache_flags(size, flags, name, ctor);
2884        s->reserved = 0;
2885
2886        if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
2887                s->reserved = sizeof(struct rcu_head);
2888
2889        if (!calculate_sizes(s, -1))
2890                goto error;
2891        if (disable_higher_order_debug) {
2892                /*
2893                 * Disable debugging flags that store metadata if the min slab
2894                 * order increased.
2895                 */
2896                if (get_order(s->size) > get_order(s->objsize)) {
2897                        s->flags &= ~DEBUG_METADATA_FLAGS;
2898                        s->offset = 0;
2899                        if (!calculate_sizes(s, -1))
2900                                goto error;
2901                }
2902        }
2903
2904#ifdef CONFIG_CMPXCHG_DOUBLE
2905        if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
2906                /* Enable fast mode */
2907                s->flags |= __CMPXCHG_DOUBLE;
2908#endif
2909
2910        /*
2911         * The larger the object size is, the more pages we want on the partial
2912         * list to avoid pounding the page allocator excessively.
2913         */
2914        set_min_partial(s, ilog2(s->size));
2915        s->refcount = 1;
2916#ifdef CONFIG_NUMA
2917        s->remote_node_defrag_ratio = 1000;
2918#endif
2919        if (!init_kmem_cache_nodes(s))
2920                goto error;
2921
2922        if (alloc_kmem_cache_cpus(s))
2923                return 1;
2924
2925        free_kmem_cache_nodes(s);
2926error:
2927        if (flags & SLAB_PANIC)
2928                panic("Cannot create slab %s size=%lu realsize=%u "
2929                        "order=%u offset=%u flags=%lx\n",
2930                        s->name, (unsigned long)size, s->size, oo_order(s->oo),
2931                        s->offset, flags);
2932        return 0;
2933}
2934
2935/*
2936 * Determine the size of a slab object
2937 */
2938unsigned int kmem_cache_size(struct kmem_cache *s)
2939{
2940        return s->objsize;
2941}
2942EXPORT_SYMBOL(kmem_cache_size);
2943
2944static void list_slab_objects(struct kmem_cache *s, struct page *page,
2945                                                        const char *text)
2946{
2947#ifdef CONFIG_SLUB_DEBUG
2948        void *addr = page_address(page);
2949        void *p;
2950        unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
2951                                     sizeof(long), GFP_ATOMIC);
2952        if (!map)
2953                return;
2954        slab_err(s, page, "%s", text);
2955        slab_lock(page);
2956
2957        get_map(s, page, map);
2958        for_each_object(p, s, addr, page->objects) {
2959
2960                if (!test_bit(slab_index(p, s, addr), map)) {
2961                        printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
2962                                                        p, p - addr);
2963                        print_tracking(s, p);
2964                }
2965        }
2966        slab_unlock(page);
2967        kfree(map);
2968#endif
2969}
2970
2971/*
2972 * Attempt to free all partial slabs on a node.
2973 */
2974static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
2975{
2976        unsigned long flags;
2977        struct page *page, *h;
2978
2979        spin_lock_irqsave(&n->list_lock, flags);
2980        list_for_each_entry_safe(page, h, &n->partial, lru) {
2981                if (!page->inuse) {
2982                        remove_partial(n, page);
2983                        discard_slab(s, page);
2984                } else {
2985                        list_slab_objects(s, page,
2986                                "Objects remaining on kmem_cache_close()");
2987                }
2988        }
2989        spin_unlock_irqrestore(&n->list_lock, flags);
2990}
2991
2992/*
2993 * Release all resources used by a slab cache.
2994 */
2995static inline int kmem_cache_close(struct kmem_cache *s)
2996{
2997        int node;
2998
2999        flush_all(s);
3000        free_percpu(s->cpu_slab);
3001        /* Attempt to free all objects */
3002        for_each_node_state(node, N_NORMAL_MEMORY) {
3003                struct kmem_cache_node *n = get_node(s, node);
3004
3005                free_partial(s, n);
3006                if (n->nr_partial || slabs_node(s, node))
3007                        return 1;
3008        }
3009        free_kmem_cache_nodes(s);
3010        return 0;
3011}
3012
3013/*
3014 * Close a cache and release the kmem_cache structure
3015 * (must be used for caches created using kmem_cache_create)
3016 */
3017void kmem_cache_destroy(struct kmem_cache *s)
3018{
3019        down_write(&slub_lock);
3020        s->refcount--;
3021        if (!s->refcount) {
3022                list_del(&s->list);
3023                if (kmem_cache_close(s)) {
3024                        printk(KERN_ERR "SLUB %s: %s called for cache that "
3025                                "still has objects.\n", s->name, __func__);
3026                        dump_stack();
3027                }
3028                if (s->flags & SLAB_DESTROY_BY_RCU)
3029                        rcu_barrier();
3030                sysfs_slab_remove(s);
3031        }
3032        up_write(&slub_lock);
3033}
3034EXPORT_SYMBOL(kmem_cache_destroy);
3035
3036/********************************************************************
3037 *              Kmalloc subsystem
3038 *******************************************************************/
3039
3040struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
3041EXPORT_SYMBOL(kmalloc_caches);
3042
3043static struct kmem_cache *kmem_cache;
3044
3045#ifdef CONFIG_ZONE_DMA
3046static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
3047#endif
3048
3049static int __init setup_slub_min_order(char *str)
3050{
3051        get_option(&str, &slub_min_order);
3052
3053        return 1;
3054}
3055
3056__setup("slub_min_order=", setup_slub_min_order);
3057
3058static int __init setup_slub_max_order(char *str)
3059{
3060        get_option(&str, &slub_max_order);
3061        slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3062
3063        return 1;
3064}
3065
3066__setup("slub_max_order=", setup_slub_max_order);
3067
3068static int __init setup_slub_min_objects(char *str)
3069{
3070        get_option(&str, &slub_min_objects);
3071
3072        return 1;
3073}
3074
3075__setup("slub_min_objects=", setup_slub_min_objects);
3076
3077static int __init setup_slub_nomerge(char *str)
3078{
3079        slub_nomerge = 1;
3080        return 1;
3081}
3082
3083__setup("slub_nomerge", setup_slub_nomerge);
3084
3085static struct kmem_cache *__init create_kmalloc_cache(const char *name,
3086                                                int size, unsigned int flags)
3087{
3088        struct kmem_cache *s;
3089
3090        s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3091
3092        /*
3093         * This function is called with IRQs disabled during early-boot on
3094         * single CPU so there's no need to take slub_lock here.
3095         */
3096        if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
3097                                                                flags, NULL))
3098                goto panic;
3099
3100        list_add(&s->list, &slab_caches);
3101        return s;
3102
3103panic:
3104        panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
3105        return NULL;
3106}
3107
3108/*
3109 * Conversion table for small slabs sizes / 8 to the index in the
3110 * kmalloc array. This is necessary for slabs < 192 since we have non power
3111 * of two cache sizes there. The size of larger slabs can be determined using
3112 * fls.
3113 */
3114static s8 size_index[24] = {
3115        3,      /* 8 */
3116        4,      /* 16 */
3117        5,      /* 24 */
3118        5,      /* 32 */
3119        6,      /* 40 */
3120        6,      /* 48 */
3121        6,      /* 56 */
3122        6,      /* 64 */
3123        1,      /* 72 */
3124        1,      /* 80 */
3125        1,      /* 88 */
3126        1,      /* 96 */
3127        7,      /* 104 */
3128        7,      /* 112 */
3129        7,      /* 120 */
3130        7,      /* 128 */
3131        2,      /* 136 */
3132        2,      /* 144 */
3133        2,      /* 152 */
3134        2,      /* 160 */
3135        2,      /* 168 */
3136        2,      /* 176 */
3137        2,      /* 184 */
3138        2       /* 192 */
3139};
3140
3141static inline int size_index_elem(size_t bytes)
3142{
3143        return (bytes - 1) / 8;
3144}
3145
3146static struct kmem_cache *get_slab(size_t size, gfp_t flags)
3147{
3148        int index;
3149
3150        if (size <= 192) {
3151                if (!size)
3152                        return ZERO_SIZE_PTR;
3153
3154                index = size_index[size_index_elem(size)];
3155        } else
3156                index = fls(size - 1);
3157
3158#ifdef CONFIG_ZONE_DMA
3159        if (unlikely((flags & SLUB_DMA)))
3160                return kmalloc_dma_caches[index];
3161
3162#endif
3163        return kmalloc_caches[index];
3164}
3165
3166void *__kmalloc(size_t size, gfp_t flags)
3167{
3168        struct kmem_cache *s;
3169        void *ret;
3170
3171        if (unlikely(size > SLUB_MAX_SIZE))
3172                return kmalloc_large(size, flags);
3173
3174        s = get_slab(size, flags);
3175
3176        if (unlikely(ZERO_OR_NULL_PTR(s)))
3177                return s;
3178
3179        ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
3180
3181        trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3182
3183        return ret;
3184}
3185EXPORT_SYMBOL(__kmalloc);
3186
3187#ifdef CONFIG_NUMA
3188static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3189{
3190        struct page *page;
3191        void *ptr = NULL;
3192
3193        flags |= __GFP_COMP | __GFP_NOTRACK;
3194        page = alloc_pages_node(node, flags, get_order(size));
3195        if (page)
3196                ptr = page_address(page);
3197
3198        kmemleak_alloc(ptr, size, 1, flags);
3199        return ptr;
3200}
3201
3202void *__kmalloc_node(size_t size, gfp_t flags, int node)
3203{
3204        struct kmem_cache *s;
3205        void *ret;
3206
3207        if (unlikely(size > SLUB_MAX_SIZE)) {
3208                ret = kmalloc_large_node(size, flags, node);
3209
3210                trace_kmalloc_node(_RET_IP_, ret,
3211                                   size, PAGE_SIZE << get_order(size),
3212                                   flags, node);
3213
3214                return ret;
3215        }
3216
3217        s = get_slab(size, flags);
3218
3219        if (unlikely(ZERO_OR_NULL_PTR(s)))
3220                return s;
3221
3222        ret = slab_alloc(s, flags, node, _RET_IP_);
3223
3224        trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3225
3226        return ret;
3227}
3228EXPORT_SYMBOL(__kmalloc_node);
3229#endif
3230
3231size_t ksize(const void *object)
3232{
3233        struct page *page;
3234
3235        if (unlikely(object == ZERO_SIZE_PTR))
3236                return 0;
3237
3238        page = virt_to_head_page(object);
3239
3240        if (unlikely(!PageSlab(page))) {
3241                WARN_ON(!PageCompound(page));
3242                return PAGE_SIZE << compound_order(page);
3243        }
3244
3245        return slab_ksize(page->slab);
3246}
3247EXPORT_SYMBOL(ksize);
3248
3249#ifdef CONFIG_SLUB_DEBUG
3250bool verify_mem_not_deleted(const void *x)
3251{
3252        struct page *page;
3253        void *object = (void *)x;
3254        unsigned long flags;
3255        bool rv;
3256
3257        if (unlikely(ZERO_OR_NULL_PTR(x)))
3258                return false;
3259
3260        local_irq_save(flags);
3261
3262        page = virt_to_head_page(x);
3263        if (unlikely(!PageSlab(page))) {
3264                /* maybe it was from stack? */
3265                rv = true;
3266                goto out_unlock;
3267        }
3268
3269        slab_lock(page);
3270        if (on_freelist(page->slab, page, object)) {
3271                object_err(page->slab, page, object, "Object is on free-list");
3272                rv = false;
3273        } else {
3274                rv = true;
3275        }
3276        slab_unlock(page);
3277
3278out_unlock:
3279        local_irq_restore(flags);
3280        return rv;
3281}
3282EXPORT_SYMBOL(verify_mem_not_deleted);
3283#endif
3284
3285void kfree(const void *x)
3286{
3287        struct page *page;
3288        void *object = (void *)x;
3289
3290        trace_kfree(_RET_IP_, x);
3291
3292        if (unlikely(ZERO_OR_NULL_PTR(x)))
3293                return;
3294
3295        page = virt_to_head_page(x);
3296        if (unlikely(!PageSlab(page))) {
3297                BUG_ON(!PageCompound(page));
3298                kmemleak_free(x);
3299                put_page(page);
3300                return;
3301        }
3302        slab_free(page->slab, page, object, _RET_IP_);
3303}
3304EXPORT_SYMBOL(kfree);
3305
3306/*
3307 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3308 * the remaining slabs by the number of items in use. The slabs with the
3309 * most items in use come first. New allocations will then fill those up
3310 * and thus they can be removed from the partial lists.
3311 *
3312 * The slabs with the least items are placed last. This results in them
3313 * being allocated from last increasing the chance that the last objects
3314 * are freed in them.
3315 */
3316int kmem_cache_shrink(struct kmem_cache *s)
3317{
3318        int node;
3319        int i;
3320        struct kmem_cache_node *n;
3321        struct page *page;
3322        struct page *t;
3323        int objects = oo_objects(s->max);
3324        struct list_head *slabs_by_inuse =
3325                kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
3326        unsigned long flags;
3327
3328        if (!slabs_by_inuse)
3329                return -ENOMEM;
3330
3331        flush_all(s);
3332        for_each_node_state(node, N_NORMAL_MEMORY) {
3333                n = get_node(s, node);
3334
3335                if (!n->nr_partial)
3336                        continue;
3337
3338                for (i = 0; i < objects; i++)
3339                        INIT_LIST_HEAD(slabs_by_inuse + i);
3340
3341                spin_lock_irqsave(&n->list_lock, flags);
3342
3343                /*
3344                 * Build lists indexed by the items in use in each slab.
3345                 *
3346                 * Note that concurrent frees may occur while we hold the
3347                 * list_lock. page->inuse here is the upper limit.
3348                 */
3349                list_for_each_entry_safe(page, t, &n->partial, lru) {
3350                        if (!page->inuse) {
3351                                remove_partial(n, page);
3352                                discard_slab(s, page);
3353                        } else {
3354                                list_move(&page->lru,
3355                                slabs_by_inuse + page->inuse);
3356                        }
3357                }
3358
3359                /*
3360                 * Rebuild the partial list with the slabs filled up most
3361                 * first and the least used slabs at the end.
3362                 */
3363                for (i = objects - 1; i >= 0; i--)
3364                        list_splice(slabs_by_inuse + i, n->partial.prev);
3365
3366                spin_unlock_irqrestore(&n->list_lock, flags);
3367        }
3368
3369        kfree(slabs_by_inuse);
3370        return 0;
3371}
3372EXPORT_SYMBOL(kmem_cache_shrink);
3373
3374#if defined(CONFIG_MEMORY_HOTPLUG)
3375static int slab_mem_going_offline_callback(void *arg)
3376{
3377        struct kmem_cache *s;
3378
3379        down_read(&slub_lock);
3380        list_for_each_entry(s, &slab_caches, list)
3381                kmem_cache_shrink(s);
3382        up_read(&slub_lock);
3383
3384        return 0;
3385}
3386
3387static void slab_mem_offline_callback(void *arg)
3388{
3389        struct kmem_cache_node *n;
3390        struct kmem_cache *s;
3391        struct memory_notify *marg = arg;
3392        int offline_node;
3393
3394        offline_node = marg->status_change_nid;
3395
3396        /*
3397         * If the node still has available memory. we need kmem_cache_node
3398         * for it yet.
3399         */
3400        if (offline_node < 0)
3401                return;
3402
3403        down_read(&slub_lock);
3404        list_for_each_entry(s, &slab_caches, list) {
3405                n = get_node(s, offline_node);
3406                if (n) {
3407                        /*
3408                         * if n->nr_slabs > 0, slabs still exist on the node
3409                         * that is going down. We were unable to free them,
3410                         * and offline_pages() function shouldn't call this
3411                         * callback. So, we must fail.
3412                         */
3413                        BUG_ON(slabs_node(s, offline_node));
3414
3415                        s->node[offline_node] = NULL;
3416                        kmem_cache_free(kmem_cache_node, n);
3417                }
3418        }
3419        up_read(&slub_lock);
3420}
3421
3422static int slab_mem_going_online_callback(void *arg)
3423{
3424        struct kmem_cache_node *n;
3425        struct kmem_cache *s;
3426        struct memory_notify *marg = arg;
3427        int nid = marg->status_change_nid;
3428        int ret = 0;
3429
3430        /*
3431         * If the node's memory is already available, then kmem_cache_node is
3432         * already created. Nothing to do.
3433         */
3434        if (nid < 0)
3435                return 0;
3436
3437        /*
3438         * We are bringing a node online. No memory is available yet. We must
3439         * allocate a kmem_cache_node structure in order to bring the node
3440         * online.
3441         */
3442        down_read(&slub_lock);
3443        list_for_each_entry(s, &slab_caches, list) {
3444                /*
3445                 * XXX: kmem_cache_alloc_node will fallback to other nodes
3446                 *      since memory is not yet available from the node that
3447                 *      is brought up.
3448                 */
3449                n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3450                if (!n) {
3451                        ret = -ENOMEM;
3452                        goto out;
3453                }
3454                init_kmem_cache_node(n, s);
3455                s->node[nid] = n;
3456        }
3457out:
3458        up_read(&slub_lock);
3459        return ret;
3460}
3461
3462static int slab_memory_callback(struct notifier_block *self,
3463                                unsigned long action, void *arg)
3464{
3465        int ret = 0;
3466
3467        switch (action) {
3468        case MEM_GOING_ONLINE:
3469                ret = slab_mem_going_online_callback(arg);
3470                break;
3471        case MEM_GOING_OFFLINE:
3472                ret = slab_mem_going_offline_callback(arg);
3473                break;
3474        case MEM_OFFLINE:
3475        case MEM_CANCEL_ONLINE:
3476                slab_mem_offline_callback(arg);
3477                break;
3478        case MEM_ONLINE:
3479        case MEM_CANCEL_OFFLINE:
3480                break;
3481        }
3482        if (ret)
3483                ret = notifier_from_errno(ret);
3484        else
3485                ret = NOTIFY_OK;
3486        return ret;
3487}
3488
3489#endif /* CONFIG_MEMORY_HOTPLUG */
3490
3491/********************************************************************
3492 *                      Basic setup of slabs
3493 *******************************************************************/
3494
3495/*
3496 * Used for early kmem_cache structures that were allocated using
3497 * the page allocator
3498 */
3499
3500static void __init kmem_cache_bootstrap_fixup(struct kmem_cache *s)
3501{
3502        int node;
3503
3504        list_add(&s->list, &slab_caches);
3505        s->refcount = -1;
3506
3507        for_each_node_state(node, N_NORMAL_MEMORY) {
3508                struct kmem_cache_node *n = get_node(s, node);
3509                struct page *p;
3510
3511                if (n) {
3512                        list_for_each_entry(p, &n->partial, lru)
3513                                p->slab = s;
3514
3515#ifdef CONFIG_SLUB_DEBUG
3516                        list_for_each_entry(p, &n->full, lru)
3517                                p->slab = s;
3518#endif
3519                }
3520        }
3521}
3522
3523void __init kmem_cache_init(void)
3524{
3525        int i;
3526        int caches = 0;
3527        struct kmem_cache *temp_kmem_cache;
3528        int order;
3529        struct kmem_cache *temp_kmem_cache_node;
3530        unsigned long kmalloc_size;
3531
3532        kmem_size = offsetof(struct kmem_cache, node) +
3533                                nr_node_ids * sizeof(struct kmem_cache_node *);
3534
3535        /* Allocate two kmem_caches from the page allocator */
3536        kmalloc_size = ALIGN(kmem_size, cache_line_size());
3537        order = get_order(2 * kmalloc_size);
3538        kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
3539
3540        /*
3541         * Must first have the slab cache available for the allocations of the
3542         * struct kmem_cache_node's. There is special bootstrap code in
3543         * kmem_cache_open for slab_state == DOWN.
3544         */
3545        kmem_cache_node = (void *)kmem_cache + kmalloc_size;
3546
3547        kmem_cache_open(kmem_cache_node, "kmem_cache_node",
3548                sizeof(struct kmem_cache_node),
3549                0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
3550
3551        hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
3552
3553        /* Able to allocate the per node structures */
3554        slab_state = PARTIAL;
3555
3556        temp_kmem_cache = kmem_cache;
3557        kmem_cache_open(kmem_cache, "kmem_cache", kmem_size,
3558                0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
3559        kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3560        memcpy(kmem_cache, temp_kmem_cache, kmem_size);
3561
3562        /*
3563         * Allocate kmem_cache_node properly from the kmem_cache slab.
3564         * kmem_cache_node is separately allocated so no need to
3565         * update any list pointers.
3566         */
3567        temp_kmem_cache_node = kmem_cache_node;
3568
3569        kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3570        memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size);
3571
3572        kmem_cache_bootstrap_fixup(kmem_cache_node);
3573
3574        caches++;
3575        kmem_cache_bootstrap_fixup(kmem_cache);
3576        caches++;
3577        /* Free temporary boot structure */
3578        free_pages((unsigned long)temp_kmem_cache, order);
3579
3580        /* Now we can use the kmem_cache to allocate kmalloc slabs */
3581
3582        /*
3583         * Patch up the size_index table if we have strange large alignment
3584         * requirements for the kmalloc array. This is only the case for
3585         * MIPS it seems. The standard arches will not generate any code here.
3586         *
3587         * Largest permitted alignment is 256 bytes due to the way we
3588         * handle the index determination for the smaller caches.
3589         *
3590         * Make sure that nothing crazy happens if someone starts tinkering
3591         * around with ARCH_KMALLOC_MINALIGN
3592         */
3593        BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
3594                (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
3595
3596        for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
3597                int elem = size_index_elem(i);
3598                if (elem >= ARRAY_SIZE(size_index))
3599                        break;
3600                size_index[elem] = KMALLOC_SHIFT_LOW;
3601        }
3602
3603        if (KMALLOC_MIN_SIZE == 64) {
3604                /*
3605                 * The 96 byte size cache is not used if the alignment
3606                 * is 64 byte.
3607                 */
3608                for (i = 64 + 8; i <= 96; i += 8)
3609                        size_index[size_index_elem(i)] = 7;
3610        } else if (KMALLOC_MIN_SIZE == 128) {
3611                /*
3612                 * The 192 byte sized cache is not used if the alignment
3613                 * is 128 byte. Redirect kmalloc to use the 256 byte cache
3614                 * instead.
3615                 */
3616                for (i = 128 + 8; i <= 192; i += 8)
3617                        size_index[size_index_elem(i)] = 8;
3618        }
3619
3620        /* Caches that are not of the two-to-the-power-of size */
3621        if (KMALLOC_MIN_SIZE <= 32) {
3622                kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
3623                caches++;
3624        }
3625
3626        if (KMALLOC_MIN_SIZE <= 64) {
3627                kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
3628                caches++;
3629        }
3630
3631        for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3632                kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
3633                caches++;
3634        }
3635
3636        slab_state = UP;
3637
3638        /* Provide the correct kmalloc names now that the caches are up */
3639        if (KMALLOC_MIN_SIZE <= 32) {
3640                kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT);
3641                BUG_ON(!kmalloc_caches[1]->name);
3642        }
3643
3644        if (KMALLOC_MIN_SIZE <= 64) {
3645                kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT);
3646                BUG_ON(!kmalloc_caches[2]->name);
3647        }
3648
3649        for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3650                char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
3651
3652                BUG_ON(!s);
3653                kmalloc_caches[i]->name = s;
3654        }
3655
3656#ifdef CONFIG_SMP
3657        register_cpu_notifier(&slab_notifier);
3658#endif
3659
3660#ifdef CONFIG_ZONE_DMA
3661        for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
3662                struct kmem_cache *s = kmalloc_caches[i];
3663
3664                if (s && s->size) {
3665                        char *name = kasprintf(GFP_NOWAIT,
3666                                 "dma-kmalloc-%d", s->objsize);
3667
3668                        BUG_ON(!name);
3669                        kmalloc_dma_caches[i] = create_kmalloc_cache(name,
3670                                s->objsize, SLAB_CACHE_DMA);
3671                }
3672        }
3673#endif
3674        printk(KERN_INFO
3675                "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3676                " CPUs=%d, Nodes=%d\n",
3677                caches, cache_line_size(),
3678                slub_min_order, slub_max_order, slub_min_objects,
3679                nr_cpu_ids, nr_node_ids);
3680}
3681
3682void __init kmem_cache_init_late(void)
3683{
3684}
3685
3686/*
3687 * Find a mergeable slab cache
3688 */
3689static int slab_unmergeable(struct kmem_cache *s)
3690{
3691        if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3692                return 1;
3693
3694        if (s->ctor)
3695                return 1;
3696
3697        /*
3698         * We may have set a slab to be unmergeable during bootstrap.
3699         */
3700        if (s->refcount < 0)
3701                return 1;
3702
3703        return 0;
3704}
3705
3706static struct kmem_cache *find_mergeable(size_t size,
3707                size_t align, unsigned long flags, const char *name,
3708                void (*ctor)(void *))
3709{
3710        struct kmem_cache *s;
3711
3712        if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3713                return NULL;
3714
3715        if (ctor)
3716                return NULL;
3717
3718        size = ALIGN(size, sizeof(void *));
3719        align = calculate_alignment(flags, align, size);
3720        size = ALIGN(size, align);
3721        flags = kmem_cache_flags(size, flags, name, NULL);
3722
3723        list_for_each_entry(s, &slab_caches, list) {
3724                if (slab_unmergeable(s))
3725                        continue;
3726
3727                if (size > s->size)
3728                        continue;
3729
3730                if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3731                                continue;
3732                /*
3733                 * Check if alignment is compatible.
3734                 * Courtesy of Adrian Drzewiecki
3735                 */
3736                if ((s->size & ~(align - 1)) != s->size)
3737                        continue;
3738
3739                if (s->size - size >= sizeof(void *))
3740                        continue;
3741
3742                return s;
3743        }
3744        return NULL;
3745}
3746
3747struct kmem_cache *kmem_cache_create(const char *name, size_t size,
3748                size_t align, unsigned long flags, void (*ctor)(void *))
3749{
3750        struct kmem_cache *s;
3751        char *n;
3752
3753        if (WARN_ON(!name))
3754                return NULL;
3755
3756        down_write(&slub_lock);
3757        s = find_mergeable(size, align, flags, name, ctor);
3758        if (s) {
3759                s->refcount++;
3760                /*
3761                 * Adjust the object sizes so that we clear
3762                 * the complete object on kzalloc.
3763                 */
3764                s->objsize = max(s->objsize, (int)size);
3765                s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3766
3767                if (sysfs_slab_alias(s, name)) {
3768                        s->refcount--;
3769                        goto err;
3770                }
3771                up_write(&slub_lock);
3772                return s;
3773        }
3774
3775        n = kstrdup(name, GFP_KERNEL);
3776        if (!n)
3777                goto err;
3778
3779        s = kmalloc(kmem_size, GFP_KERNEL);
3780        if (s) {
3781                if (kmem_cache_open(s, n,
3782                                size, align, flags, ctor)) {
3783                        list_add(&s->list, &slab_caches);
3784                        if (sysfs_slab_add(s)) {
3785                                list_del(&s->list);
3786                                kfree(n);
3787                                kfree(s);
3788                                goto err;
3789                        }
3790                        up_write(&slub_lock);
3791                        return s;
3792                }
3793                kfree(n);
3794                kfree(s);
3795        }
3796err:
3797        up_write(&slub_lock);
3798
3799        if (flags & SLAB_PANIC)
3800                panic("Cannot create slabcache %s\n", name);
3801        else
3802                s = NULL;
3803        return s;
3804}
3805EXPORT_SYMBOL(kmem_cache_create);
3806
3807#ifdef CONFIG_SMP
3808/*
3809 * Use the cpu notifier to insure that the cpu slabs are flushed when
3810 * necessary.
3811 */
3812static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3813                unsigned long action, void *hcpu)
3814{
3815        long cpu = (long)hcpu;
3816        struct kmem_cache *s;
3817        unsigned long flags;
3818
3819        switch (action) {
3820        case CPU_UP_CANCELED:
3821        case CPU_UP_CANCELED_FROZEN:
3822        case CPU_DEAD:
3823        case CPU_DEAD_FROZEN:
3824                down_read(&slub_lock);
3825                list_for_each_entry(s, &slab_caches, list) {
3826                        local_irq_save(flags);
3827                        __flush_cpu_slab(s, cpu);
3828                        local_irq_restore(flags);
3829                }
3830                up_read(&slub_lock);
3831                break;
3832        default:
3833                break;
3834        }
3835        return NOTIFY_OK;
3836}
3837
3838static struct notifier_block __cpuinitdata slab_notifier = {
3839        .notifier_call = slab_cpuup_callback
3840};
3841
3842#endif
3843
3844void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
3845{
3846        struct kmem_cache *s;
3847        void *ret;
3848
3849        if (unlikely(size > SLUB_MAX_SIZE))
3850                return kmalloc_large(size, gfpflags);
3851
3852        s = get_slab(size, gfpflags);
3853
3854        if (unlikely(ZERO_OR_NULL_PTR(s)))
3855                return s;
3856
3857        ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, caller);
3858
3859        /* Honor the call site pointer we received. */
3860        trace_kmalloc(caller, ret, size, s->size, gfpflags);
3861
3862        return ret;
3863}
3864
3865#ifdef CONFIG_NUMA
3866void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3867                                        int node, unsigned long caller)
3868{
3869        struct kmem_cache *s;
3870        void *ret;
3871
3872        if (unlikely(size > SLUB_MAX_SIZE)) {
3873                ret = kmalloc_large_node(size, gfpflags, node);
3874
3875                trace_kmalloc_node(caller, ret,
3876                                   size, PAGE_SIZE << get_order(size),
3877                                   gfpflags, node);
3878
3879                return ret;
3880        }
3881
3882        s = get_slab(size, gfpflags);
3883
3884        if (unlikely(ZERO_OR_NULL_PTR(s)))
3885                return s;
3886
3887        ret = slab_alloc(s, gfpflags, node, caller);
3888
3889        /* Honor the call site pointer we received. */
3890        trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
3891
3892        return ret;
3893}
3894#endif
3895
3896#ifdef CONFIG_SYSFS
3897static int count_inuse(struct page *page)
3898{
3899        return page->inuse;
3900}
3901
3902static int count_total(struct page *page)
3903{
3904        return page->objects;
3905}
3906#endif
3907
3908#ifdef CONFIG_SLUB_DEBUG
3909static int validate_slab(struct kmem_cache *s, struct page *page,
3910                                                unsigned long *map)
3911{
3912        void *p;
3913        void *addr = page_address(page);
3914
3915        if (!check_slab(s, page) ||
3916                        !on_freelist(s, page, NULL))
3917                return 0;
3918
3919        /* Now we know that a valid freelist exists */
3920        bitmap_zero(map, page->objects);
3921
3922        get_map(s, page, map);
3923        for_each_object(p, s, addr, page->objects) {
3924                if (test_bit(slab_index(p, s, addr), map))
3925                        if (!check_object(s, page, p, SLUB_RED_INACTIVE))
3926                                return 0;
3927        }
3928
3929        for_each_object(p, s, addr, page->objects)
3930                if (!test_bit(slab_index(p, s, addr), map))
3931                        if (!check_object(s, page, p, SLUB_RED_ACTIVE))
3932                                return 0;
3933        return 1;
3934}
3935
3936static void validate_slab_slab(struct kmem_cache *s, struct page *page,
3937                                                unsigned long *map)
3938{
3939        slab_lock(page);
3940        validate_slab(s, page, map);
3941        slab_unlock(page);
3942}
3943
3944static int validate_slab_node(struct kmem_cache *s,
3945                struct kmem_cache_node *n, unsigned long *map)
3946{
3947        unsigned long count = 0;
3948        struct page *page;
3949        unsigned long flags;
3950
3951        spin_lock_irqsave(&n->list_lock, flags);
3952
3953        list_for_each_entry(page, &n->partial, lru) {
3954                validate_slab_slab(s, page, map);
3955                count++;
3956        }
3957        if (count != n->nr_partial)
3958                printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
3959                        "counter=%ld\n", s->name, count, n->nr_partial);
3960
3961        if (!(s->flags & SLAB_STORE_USER))
3962                goto out;
3963
3964        list_for_each_entry(page, &n->full, lru) {
3965                validate_slab_slab(s, page, map);
3966                count++;
3967        }
3968        if (count != atomic_long_read(&n->nr_slabs))
3969                printk(KERN_ERR "SLUB: %s %ld slabs counted but "
3970                        "counter=%ld\n", s->name, count,
3971                        atomic_long_read(&n->nr_slabs));
3972
3973out:
3974        spin_unlock_irqrestore(&n->list_lock, flags);
3975        return count;
3976}
3977
3978static long validate_slab_cache(struct kmem_cache *s)
3979{
3980        int node;
3981        unsigned long count = 0;
3982        unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
3983                                sizeof(unsigned long), GFP_KERNEL);
3984
3985        if (!map)
3986                return -ENOMEM;
3987
3988        flush_all(s);
3989        for_each_node_state(node, N_NORMAL_MEMORY) {
3990                struct kmem_cache_node *n = get_node(s, node);
3991
3992                count += validate_slab_node(s, n, map);
3993        }
3994        kfree(map);
3995        return count;
3996}
3997/*
3998 * Generate lists of code addresses where slabcache objects are allocated
3999 * and freed.
4000 */
4001
4002struct location {
4003        unsigned long count;
4004        unsigned long addr;
4005        long long sum_time;
4006        long min_time;
4007        long max_time;
4008        long min_pid;
4009        long max_pid;
4010        DECLARE_BITMAP(cpus, NR_CPUS);
4011        nodemask_t nodes;
4012};
4013
4014struct loc_track {
4015        unsigned long max;
4016        unsigned long count;
4017        struct location *loc;
4018};
4019
4020static void free_loc_track(struct loc_track *t)
4021{
4022        if (t->max)
4023                free_pages((unsigned long)t->loc,
4024                        get_order(sizeof(struct location) * t->max));
4025}
4026
4027static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4028{
4029        struct location *l;
4030        int order;
4031
4032        order = get_order(sizeof(struct location) * max);
4033
4034        l = (void *)__get_free_pages(flags, order);
4035        if (!l)
4036                return 0;
4037
4038        if (t->count) {
4039                memcpy(l, t->loc, sizeof(struct location) * t->count);
4040                free_loc_track(t);
4041        }
4042        t->max = max;
4043        t->loc = l;
4044        return 1;
4045}
4046
4047static int add_location(struct loc_track *t, struct kmem_cache *s,
4048                                const struct track *track)
4049{
4050        long start, end, pos;
4051        struct location *l;
4052        unsigned long caddr;
4053        unsigned long age = jiffies - track->when;
4054
4055        start = -1;
4056        end = t->count;
4057
4058        for ( ; ; ) {
4059                pos = start + (end - start + 1) / 2;
4060
4061                /*
4062                 * There is nothing at "end". If we end up there
4063                 * we need to add something to before end.
4064                 */
4065                if (pos == end)
4066                        break;
4067
4068                caddr = t->loc[pos].addr;
4069                if (track->addr == caddr) {
4070
4071                        l = &t->loc[pos];
4072                        l->count++;
4073                        if (track->when) {
4074                                l->sum_time += age;
4075                                if (age < l->min_time)
4076                                        l->min_time = age;
4077                                if (age > l->max_time)
4078                                        l->max_time = age;
4079
4080                                if (track->pid < l->min_pid)
4081                                        l->min_pid = track->pid;
4082                                if (track->pid > l->max_pid)
4083                                        l->max_pid = track->pid;
4084
4085                                cpumask_set_cpu(track->cpu,
4086                                                to_cpumask(l->cpus));
4087                        }
4088                        node_set(page_to_nid(virt_to_page(track)), l->nodes);
4089                        return 1;
4090                }
4091
4092                if (track->addr < caddr)
4093                        end = pos;
4094                else
4095                        start = pos;
4096        }
4097
4098        /*
4099         * Not found. Insert new tracking element.
4100         */
4101        if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4102                return 0;
4103
4104        l = t->loc + pos;
4105        if (pos < t->count)
4106                memmove(l + 1, l,
4107                        (t->count - pos) * sizeof(struct location));
4108        t->count++;
4109        l->count = 1;
4110        l->addr = track->addr;
4111        l->sum_time = age;
4112        l->min_time = age;
4113        l->max_time = age;
4114        l->min_pid = track->pid;
4115        l->max_pid = track->pid;
4116        cpumask_clear(to_cpumask(l->cpus));
4117        cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4118        nodes_clear(l->nodes);
4119        node_set(page_to_nid(virt_to_page(track)), l->nodes);
4120        return 1;
4121}
4122
4123static void process_slab(struct loc_track *t, struct kmem_cache *s,
4124                struct page *page, enum track_item alloc,
4125                unsigned long *map)
4126{
4127        void *addr = page_address(page);
4128        void *p;
4129
4130        bitmap_zero(map, page->objects);
4131        get_map(s, page, map);
4132
4133        for_each_object(p, s, addr, page->objects)
4134                if (!test_bit(slab_index(p, s, addr), map))
4135                        add_location(t, s, get_track(s, p, alloc));
4136}
4137
4138static int list_locations(struct kmem_cache *s, char *buf,
4139                                        enum track_item alloc)
4140{
4141        int len = 0;
4142        unsigned long i;
4143        struct loc_track t = { 0, 0, NULL };
4144        int node;
4145        unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4146                                     sizeof(unsigned long), GFP_KERNEL);
4147
4148        if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4149                                     GFP_TEMPORARY)) {
4150                kfree(map);
4151                return sprintf(buf, "Out of memory\n");
4152        }
4153        /* Push back cpu slabs */
4154        flush_all(s);
4155
4156        for_each_node_state(node, N_NORMAL_MEMORY) {
4157                struct kmem_cache_node *n = get_node(s, node);
4158                unsigned long flags;
4159                struct page *page;
4160
4161                if (!atomic_long_read(&n->nr_slabs))
4162                        continue;
4163
4164                spin_lock_irqsave(&n->list_lock, flags);
4165                list_for_each_entry(page, &n->partial, lru)
4166                        process_slab(&t, s, page, alloc, map);
4167                list_for_each_entry(page, &n->full, lru)
4168                        process_slab(&t, s, page, alloc, map);
4169                spin_unlock_irqrestore(&n->list_lock, flags);
4170        }
4171
4172        for (i = 0; i < t.count; i++) {
4173                struct location *l = &t.loc[i];
4174
4175                if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4176                        break;
4177                len += sprintf(buf + len, "%7ld ", l->count);
4178
4179                if (l->addr)
4180                        len += sprintf(buf + len, "%pS", (void *)l->addr);
4181                else
4182                        len += sprintf(buf + len, "<not-available>");
4183
4184                if (l->sum_time != l->min_time) {
4185                        len += sprintf(buf + len, " age=%ld/%ld/%ld",
4186                                l->min_time,
4187                                (long)div_u64(l->sum_time, l->count),
4188                                l->max_time);
4189                } else
4190                        len += sprintf(buf + len, " age=%ld",
4191                                l->min_time);
4192
4193                if (l->min_pid != l->max_pid)
4194                        len += sprintf(buf + len, " pid=%ld-%ld",
4195                                l->min_pid, l->max_pid);
4196                else
4197                        len += sprintf(buf + len, " pid=%ld",
4198                                l->min_pid);
4199
4200                if (num_online_cpus() > 1 &&
4201                                !cpumask_empty(to_cpumask(l->cpus)) &&
4202                                len < PAGE_SIZE - 60) {
4203                        len += sprintf(buf + len, " cpus=");
4204                        len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4205                                                 to_cpumask(l->cpus));
4206                }
4207
4208                if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4209                                len < PAGE_SIZE - 60) {
4210                        len += sprintf(buf + len, " nodes=");
4211                        len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4212                                        l->nodes);
4213                }
4214
4215                len += sprintf(buf + len, "\n");
4216        }
4217
4218        free_loc_track(&t);
4219        kfree(map);
4220        if (!t.count)
4221                len += sprintf(buf, "No data\n");
4222        return len;
4223}
4224#endif
4225
4226#ifdef SLUB_RESILIENCY_TEST
4227static void resiliency_test(void)
4228{
4229        u8 *p;
4230
4231        BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10);
4232
4233        printk(KERN_ERR "SLUB resiliency testing\n");
4234        printk(KERN_ERR "-----------------------\n");
4235        printk(KERN_ERR "A. Corruption after allocation\n");
4236
4237        p = kzalloc(16, GFP_KERNEL);
4238        p[16] = 0x12;
4239        printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
4240                        " 0x12->0x%p\n\n", p + 16);
4241
4242        validate_slab_cache(kmalloc_caches[4]);
4243
4244        /* Hmmm... The next two are dangerous */
4245        p = kzalloc(32, GFP_KERNEL);
4246        p[32 + sizeof(void *)] = 0x34;
4247        printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
4248                        " 0x34 -> -0x%p\n", p);
4249        printk(KERN_ERR
4250                "If allocated object is overwritten then not detectable\n\n");
4251
4252        validate_slab_cache(kmalloc_caches[5]);
4253        p = kzalloc(64, GFP_KERNEL);
4254        p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4255        *p = 0x56;
4256        printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4257                                                                        p);
4258        printk(KERN_ERR
4259                "If allocated object is overwritten then not detectable\n\n");
4260        validate_slab_cache(kmalloc_caches[6]);
4261
4262        printk(KERN_ERR "\nB. Corruption after free\n");
4263        p = kzalloc(128, GFP_KERNEL);
4264        kfree(p);
4265        *p = 0x78;
4266        printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4267        validate_slab_cache(kmalloc_caches[7]);
4268
4269        p = kzalloc(256, GFP_KERNEL);
4270        kfree(p);
4271        p[50] = 0x9a;
4272        printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4273                        p);
4274        validate_slab_cache(kmalloc_caches[8]);
4275
4276        p = kzalloc(512, GFP_KERNEL);
4277        kfree(p);
4278        p[512] = 0xab;
4279        printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4280        validate_slab_cache(kmalloc_caches[9]);
4281}
4282#else
4283#ifdef CONFIG_SYSFS
4284static void resiliency_test(void) {};
4285#endif
4286#endif
4287
4288#ifdef CONFIG_SYSFS
4289enum slab_stat_type {
4290        SL_ALL,                 /* All slabs */
4291        SL_PARTIAL,             /* Only partially allocated slabs */
4292        SL_CPU,                 /* Only slabs used for cpu caches */
4293        SL_OBJECTS,             /* Determine allocated objects not slabs */
4294        SL_TOTAL                /* Determine object capacity not slabs */
4295};
4296
4297#define SO_ALL          (1 << SL_ALL)
4298#define SO_PARTIAL      (1 << SL_PARTIAL)
4299#define SO_CPU          (1 << SL_CPU)
4300#define SO_OBJECTS      (1 << SL_OBJECTS)
4301#define SO_TOTAL        (1 << SL_TOTAL)
4302
4303static ssize_t show_slab_objects(struct kmem_cache *s,
4304                            char *buf, unsigned long flags)
4305{
4306        unsigned long total = 0;
4307        int node;
4308        int x;
4309        unsigned long *nodes;
4310        unsigned long *per_cpu;
4311
4312        nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4313        if (!nodes)
4314                return -ENOMEM;
4315        per_cpu = nodes + nr_node_ids;
4316
4317        if (flags & SO_CPU) {
4318                int cpu;
4319
4320                for_each_possible_cpu(cpu) {
4321                        struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
4322
4323                        if (!c || c->node < 0)
4324                                continue;
4325
4326                        if (c->page) {
4327                                        if (flags & SO_TOTAL)
4328                                                x = c->page->objects;
4329                                else if (flags & SO_OBJECTS)
4330                                        x = c->page->inuse;
4331                                else
4332                                        x = 1;
4333
4334                                total += x;
4335                                nodes[c->node] += x;
4336                        }
4337                        per_cpu[c->node]++;
4338                }
4339        }
4340
4341        lock_memory_hotplug();
4342#ifdef CONFIG_SLUB_DEBUG
4343        if (flags & SO_ALL) {
4344                for_each_node_state(node, N_NORMAL_MEMORY) {
4345                        struct kmem_cache_node *n = get_node(s, node);
4346
4347                if (flags & SO_TOTAL)
4348                        x = atomic_long_read(&n->total_objects);
4349                else if (flags & SO_OBJECTS)
4350                        x = atomic_long_read(&n->total_objects) -
4351                                count_partial(n, count_free);
4352
4353                        else
4354                                x = atomic_long_read(&n->nr_slabs);
4355                        total += x;
4356                        nodes[node] += x;
4357                }
4358
4359        } else
4360#endif
4361        if (flags & SO_PARTIAL) {
4362                for_each_node_state(node, N_NORMAL_MEMORY) {
4363                        struct kmem_cache_node *n = get_node(s, node);
4364
4365                        if (flags & SO_TOTAL)
4366                                x = count_partial(n, count_total);
4367                        else if (flags & SO_OBJECTS)
4368                                x = count_partial(n, count_inuse);
4369                        else
4370                                x = n->nr_partial;
4371                        total += x;
4372                        nodes[node] += x;
4373                }
4374        }
4375        x = sprintf(buf, "%lu", total);
4376#ifdef CONFIG_NUMA
4377        for_each_node_state(node, N_NORMAL_MEMORY)
4378                if (nodes[node])
4379                        x += sprintf(buf + x, " N%d=%lu",
4380                                        node, nodes[node]);
4381#endif
4382        unlock_memory_hotplug();
4383        kfree(nodes);
4384        return x + sprintf(buf + x, "\n");
4385}
4386
4387#ifdef CONFIG_SLUB_DEBUG
4388static int any_slab_objects(struct kmem_cache *s)
4389{
4390        int node;
4391
4392        for_each_online_node(node) {
4393                struct kmem_cache_node *n = get_node(s, node);
4394
4395                if (!n)
4396                        continue;
4397
4398                if (atomic_long_read(&n->total_objects))
4399                        return 1;
4400        }
4401        return 0;
4402}
4403#endif
4404
4405#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4406#define to_slab(n) container_of(n, struct kmem_cache, kobj)
4407
4408struct slab_attribute {
4409        struct attribute attr;
4410        ssize_t (*show)(struct kmem_cache *s, char *buf);
4411        ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4412};
4413
4414#define SLAB_ATTR_RO(_name) \
4415        static struct slab_attribute _name##_attr = __ATTR_RO(_name)
4416
4417#define SLAB_ATTR(_name) \
4418        static struct slab_attribute _name##_attr =  \
4419        __ATTR(_name, 0644, _name##_show, _name##_store)
4420
4421static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4422{
4423        return sprintf(buf, "%d\n", s->size);
4424}
4425SLAB_ATTR_RO(slab_size);
4426
4427static ssize_t align_show(struct kmem_cache *s, char *buf)
4428{
4429        return sprintf(buf, "%d\n", s->align);
4430}
4431SLAB_ATTR_RO(align);
4432
4433static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4434{
4435        return sprintf(buf, "%d\n", s->objsize);
4436}
4437SLAB_ATTR_RO(object_size);
4438
4439static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4440{
4441        return sprintf(buf, "%d\n", oo_objects(s->oo));
4442}
4443SLAB_ATTR_RO(objs_per_slab);
4444
4445static ssize_t order_store(struct kmem_cache *s,
4446                                const char *buf, size_t length)
4447{
4448        unsigned long order;
4449        int err;
4450
4451        err = strict_strtoul(buf, 10, &order);
4452        if (err)
4453                return err;
4454
4455        if (order > slub_max_order || order < slub_min_order)
4456                return -EINVAL;
4457
4458        calculate_sizes(s, order);
4459        return length;
4460}
4461
4462static ssize_t order_show(struct kmem_cache *s, char *buf)
4463{
4464        return sprintf(buf, "%d\n", oo_order(s->oo));
4465}
4466SLAB_ATTR(order);
4467
4468static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4469{
4470        return sprintf(buf, "%lu\n", s->min_partial);
4471}
4472
4473static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4474                                 size_t length)
4475{
4476        unsigned long min;
4477        int err;
4478
4479        err = strict_strtoul(buf, 10, &min);
4480        if (err)
4481                return err;
4482
4483        set_min_partial(s, min);
4484        return length;
4485}
4486SLAB_ATTR(min_partial);
4487
4488static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4489{
4490        if (!s->ctor)
4491                return 0;
4492        return sprintf(buf, "%pS\n", s->ctor);
4493}
4494SLAB_ATTR_RO(ctor);
4495
4496static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4497{
4498        return sprintf(buf, "%d\n", s->refcount - 1);
4499}
4500SLAB_ATTR_RO(aliases);
4501
4502static ssize_t partial_show(struct kmem_cache *s, char *buf)
4503{
4504        return show_slab_objects(s, buf, SO_PARTIAL);
4505}
4506SLAB_ATTR_RO(partial);
4507
4508static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4509{
4510        return show_slab_objects(s, buf, SO_CPU);
4511}
4512SLAB_ATTR_RO(cpu_slabs);
4513
4514static ssize_t objects_show(struct kmem_cache *s, char *buf)
4515{
4516        return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4517}
4518SLAB_ATTR_RO(objects);
4519
4520static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4521{
4522        return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4523}
4524SLAB_ATTR_RO(objects_partial);
4525
4526static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4527{
4528        return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4529}
4530
4531static ssize_t reclaim_account_store(struct kmem_cache *s,
4532                                const char *buf, size_t length)
4533{
4534        s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4535        if (buf[0] == '1')
4536                s->flags |= SLAB_RECLAIM_ACCOUNT;
4537        return length;
4538}
4539SLAB_ATTR(reclaim_account);
4540
4541static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4542{
4543        return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4544}
4545SLAB_ATTR_RO(hwcache_align);
4546
4547#ifdef CONFIG_ZONE_DMA
4548static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4549{
4550        return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4551}
4552SLAB_ATTR_RO(cache_dma);
4553#endif
4554
4555static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4556{
4557        return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4558}
4559SLAB_ATTR_RO(destroy_by_rcu);
4560
4561static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4562{
4563        return sprintf(buf, "%d\n", s->reserved);
4564}
4565SLAB_ATTR_RO(reserved);
4566
4567#ifdef CONFIG_SLUB_DEBUG
4568static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4569{
4570        return show_slab_objects(s, buf, SO_ALL);
4571}
4572SLAB_ATTR_RO(slabs);
4573
4574static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4575{
4576        return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4577}
4578SLAB_ATTR_RO(total_objects);
4579
4580static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4581{
4582        return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4583}
4584
4585static ssize_t sanity_checks_store(struct kmem_cache *s,
4586                                const char *buf, size_t length)
4587{
4588        s->flags &= ~SLAB_DEBUG_FREE;
4589        if (buf[0] == '1') {
4590                s->flags &= ~__CMPXCHG_DOUBLE;
4591                s->flags |= SLAB_DEBUG_FREE;
4592        }
4593        return length;
4594}
4595SLAB_ATTR(sanity_checks);
4596
4597static ssize_t trace_show(struct kmem_cache *s, char *buf)
4598{
4599        return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4600}
4601
4602static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4603                                                        size_t length)
4604{
4605        s->flags &= ~SLAB_TRACE;
4606        if (buf[0] == '1') {
4607                s->flags &= ~__CMPXCHG_DOUBLE;
4608                s->flags |= SLAB_TRACE;
4609        }
4610        return length;
4611}
4612SLAB_ATTR(trace);
4613
4614static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4615{
4616        return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4617}
4618
4619static ssize_t red_zone_store(struct kmem_cache *s,
4620                                const char *buf, size_t length)
4621{
4622        if (any_slab_objects(s))
4623                return -EBUSY;
4624
4625        s->flags &= ~SLAB_RED_ZONE;
4626        if (buf[0] == '1') {
4627                s->flags &= ~__CMPXCHG_DOUBLE;
4628                s->flags |= SLAB_RED_ZONE;
4629        }
4630        calculate_sizes(s, -1);
4631        return length;
4632}
4633SLAB_ATTR(red_zone);
4634
4635static ssize_t poison_show(struct kmem_cache *s, char *buf)
4636{
4637        return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4638}
4639
4640static ssize_t poison_store(struct kmem_cache *s,
4641                                const char *buf, size_t length)
4642{
4643        if (any_slab_objects(s))
4644                return -EBUSY;
4645
4646        s->flags &= ~SLAB_POISON;
4647        if (buf[0] == '1') {
4648                s->flags &= ~__CMPXCHG_DOUBLE;
4649                s->flags |= SLAB_POISON;
4650        }
4651        calculate_sizes(s, -1);
4652        return length;
4653}
4654SLAB_ATTR(poison);
4655
4656static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4657{
4658        return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4659}
4660
4661static ssize_t store_user_store(struct kmem_cache *s,
4662                                const char *buf, size_t length)
4663{
4664        if (any_slab_objects(s))
4665                return -EBUSY;
4666
4667        s->flags &= ~SLAB_STORE_USER;
4668        if (buf[0] == '1') {
4669                s->flags &= ~__CMPXCHG_DOUBLE;
4670                s->flags |= SLAB_STORE_USER;
4671        }
4672        calculate_sizes(s, -1);
4673        return length;
4674}
4675SLAB_ATTR(store_user);
4676
4677static ssize_t validate_show(struct kmem_cache *s, char *buf)
4678{
4679        return 0;
4680}
4681
4682static ssize_t validate_store(struct kmem_cache *s,
4683                        const char *buf, size_t length)
4684{
4685        int ret = -EINVAL;
4686
4687        if (buf[0] == '1') {
4688                ret = validate_slab_cache(s);
4689                if (ret >= 0)
4690                        ret = length;
4691        }
4692        return ret;
4693}
4694SLAB_ATTR(validate);
4695
4696static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4697{
4698        if (!(s->flags & SLAB_STORE_USER))
4699                return -ENOSYS;
4700        return list_locations(s, buf, TRACK_ALLOC);
4701}
4702SLAB_ATTR_RO(alloc_calls);
4703
4704static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4705{
4706        if (!(s->flags & SLAB_STORE_USER))
4707                return -ENOSYS;
4708        return list_locations(s, buf, TRACK_FREE);
4709}
4710SLAB_ATTR_RO(free_calls);
4711#endif /* CONFIG_SLUB_DEBUG */
4712
4713#ifdef CONFIG_FAILSLAB
4714static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4715{
4716        return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4717}
4718
4719static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4720                                                        size_t length)
4721{
4722        s->flags &= ~SLAB_FAILSLAB;
4723        if (buf[0] == '1')
4724                s->flags |= SLAB_FAILSLAB;
4725        return length;
4726}
4727SLAB_ATTR(failslab);
4728#endif
4729
4730static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4731{
4732        return 0;
4733}
4734
4735static ssize_t shrink_store(struct kmem_cache *s,
4736                        const char *buf, size_t length)
4737{
4738        if (buf[0] == '1') {
4739                int rc = kmem_cache_shrink(s);
4740
4741                if (rc)
4742                        return rc;
4743        } else
4744                return -EINVAL;
4745        return length;
4746}
4747SLAB_ATTR(shrink);
4748
4749#ifdef CONFIG_NUMA
4750static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4751{
4752        return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4753}
4754
4755static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
4756                                const char *buf, size_t length)
4757{
4758        unsigned long ratio;
4759        int err;
4760
4761        err = strict_strtoul(buf, 10, &ratio);
4762        if (err)
4763                return err;
4764
4765        if (ratio <= 100)
4766                s->remote_node_defrag_ratio = ratio * 10;
4767
4768        return length;
4769}
4770SLAB_ATTR(remote_node_defrag_ratio);
4771#endif
4772
4773#ifdef CONFIG_SLUB_STATS
4774static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
4775{
4776        unsigned long sum  = 0;
4777        int cpu;
4778        int len;
4779        int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
4780
4781        if (!data)
4782                return -ENOMEM;
4783
4784        for_each_online_cpu(cpu) {
4785                unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
4786
4787                data[cpu] = x;
4788                sum += x;
4789        }
4790
4791        len = sprintf(buf, "%lu", sum);
4792
4793#ifdef CONFIG_SMP
4794        for_each_online_cpu(cpu) {
4795                if (data[cpu] && len < PAGE_SIZE - 20)
4796                        len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
4797        }
4798#endif
4799        kfree(data);
4800        return len + sprintf(buf + len, "\n");
4801}
4802
4803static void clear_stat(struct kmem_cache *s, enum stat_item si)
4804{
4805        int cpu;
4806
4807        for_each_online_cpu(cpu)
4808                per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
4809}
4810
4811#define STAT_ATTR(si, text)                                     \
4812static ssize_t text##_show(struct kmem_cache *s, char *buf)     \
4813{                                                               \
4814        return show_stat(s, buf, si);                           \
4815}                                                               \
4816static ssize_t text##_store(struct kmem_cache *s,               \
4817                                const char *buf, size_t length) \
4818{                                                               \
4819        if (buf[0] != '0')                                      \
4820                return -EINVAL;                                 \
4821        clear_stat(s, si);                                      \
4822        return length;                                          \
4823}                                                               \
4824SLAB_ATTR(text);                                                \
4825
4826STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4827STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
4828STAT_ATTR(FREE_FASTPATH, free_fastpath);
4829STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4830STAT_ATTR(FREE_FROZEN, free_frozen);
4831STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4832STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4833STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4834STAT_ATTR(ALLOC_SLAB, alloc_slab);
4835STAT_ATTR(ALLOC_REFILL, alloc_refill);
4836STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
4837STAT_ATTR(FREE_SLAB, free_slab);
4838STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4839STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4840STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4841STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4842STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4843STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4844STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
4845STAT_ATTR(ORDER_FALLBACK, order_fallback);
4846STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
4847STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
4848#endif
4849
4850static struct attribute *slab_attrs[] = {
4851        &slab_size_attr.attr,
4852        &object_size_attr.attr,
4853        &objs_per_slab_attr.attr,
4854        &order_attr.attr,
4855        &min_partial_attr.attr,
4856        &objects_attr.attr,
4857        &objects_partial_attr.attr,
4858        &partial_attr.attr,
4859        &cpu_slabs_attr.attr,
4860        &ctor_attr.attr,
4861        &aliases_attr.attr,
4862        &align_attr.attr,
4863        &hwcache_align_attr.attr,
4864        &reclaim_account_attr.attr,
4865        &destroy_by_rcu_attr.attr,
4866        &shrink_attr.attr,
4867        &reserved_attr.attr,
4868#ifdef CONFIG_SLUB_DEBUG
4869        &total_objects_attr.attr,
4870        &slabs_attr.attr,
4871        &sanity_checks_attr.attr,
4872        &trace_attr.attr,
4873        &red_zone_attr.attr,
4874        &poison_attr.attr,
4875        &store_user_attr.attr,
4876        &validate_attr.attr,
4877        &alloc_calls_attr.attr,
4878        &free_calls_attr.attr,
4879#endif
4880#ifdef CONFIG_ZONE_DMA
4881        &cache_dma_attr.attr,
4882#endif
4883#ifdef CONFIG_NUMA
4884        &remote_node_defrag_ratio_attr.attr,
4885#endif
4886#ifdef CONFIG_SLUB_STATS
4887        &alloc_fastpath_attr.attr,
4888        &alloc_slowpath_attr.attr,
4889        &free_fastpath_attr.attr,
4890        &free_slowpath_attr.attr,
4891        &free_frozen_attr.attr,
4892        &free_add_partial_attr.attr,
4893        &free_remove_partial_attr.attr,
4894        &alloc_from_partial_attr.attr,
4895        &alloc_slab_attr.attr,
4896        &alloc_refill_attr.attr,
4897        &alloc_node_mismatch_attr.attr,
4898        &free_slab_attr.attr,
4899        &cpuslab_flush_attr.attr,
4900        &deactivate_full_attr.attr,
4901        &deactivate_empty_attr.attr,
4902        &deactivate_to_head_attr.attr,
4903        &deactivate_to_tail_attr.attr,
4904        &deactivate_remote_frees_attr.attr,
4905        &deactivate_bypass_attr.attr,
4906        &order_fallback_attr.attr,
4907        &cmpxchg_double_fail_attr.attr,
4908        &cmpxchg_double_cpu_fail_attr.attr,
4909#endif
4910#ifdef CONFIG_FAILSLAB
4911        &failslab_attr.attr,
4912#endif
4913
4914        NULL
4915};
4916
4917static struct attribute_group slab_attr_group = {
4918        .attrs = slab_attrs,
4919};
4920
4921static ssize_t slab_attr_show(struct kobject *kobj,
4922                                struct attribute *attr,
4923                                char *buf)
4924{
4925        struct slab_attribute *attribute;
4926        struct kmem_cache *s;
4927        int err;
4928
4929        attribute = to_slab_attr(attr);
4930        s = to_slab(kobj);
4931
4932        if (!attribute->show)
4933                return -EIO;
4934
4935        err = attribute->show(s, buf);
4936
4937        return err;
4938}
4939
4940static ssize_t slab_attr_store(struct kobject *kobj,
4941                                struct attribute *attr,
4942                                const char *buf, size_t len)
4943{
4944        struct slab_attribute *attribute;
4945        struct kmem_cache *s;
4946        int err;
4947
4948        attribute = to_slab_attr(attr);
4949        s = to_slab(kobj);
4950
4951        if (!attribute->store)
4952                return -EIO;
4953
4954        err = attribute->store(s, buf, len);
4955
4956        return err;
4957}
4958
4959static void kmem_cache_release(struct kobject *kobj)
4960{
4961        struct kmem_cache *s = to_slab(kobj);
4962
4963        kfree(s->name);
4964        kfree(s);
4965}
4966
4967static const struct sysfs_ops slab_sysfs_ops = {
4968        .show = slab_attr_show,
4969        .store = slab_attr_store,
4970};
4971
4972static struct kobj_type slab_ktype = {
4973        .sysfs_ops = &slab_sysfs_ops,
4974        .release = kmem_cache_release
4975};
4976
4977static int uevent_filter(struct kset *kset, struct kobject *kobj)
4978{
4979        struct kobj_type *ktype = get_ktype(kobj);
4980
4981        if (ktype == &slab_ktype)
4982                return 1;
4983        return 0;
4984}
4985
4986static const struct kset_uevent_ops slab_uevent_ops = {
4987        .filter = uevent_filter,
4988};
4989
4990static struct kset *slab_kset;
4991
4992#define ID_STR_LENGTH 64
4993
4994/* Create a unique string id for a slab cache:
4995 *
4996 * Format       :[flags-]size
4997 */
4998static char *create_unique_id(struct kmem_cache *s)
4999{
5000        char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5001        char *p = name;
5002
5003        BUG_ON(!name);
5004
5005        *p++ = ':';
5006        /*
5007         * First flags affecting slabcache operations. We will only
5008         * get here for aliasable slabs so we do not need to support
5009         * too many flags. The flags here must cover all flags that
5010         * are matched during merging to guarantee that the id is
5011         * unique.
5012         */
5013        if (s->flags & SLAB_CACHE_DMA)
5014                *p++ = 'd';
5015        if (s->flags & SLAB_RECLAIM_ACCOUNT)
5016                *p++ = 'a';
5017        if (s->flags & SLAB_DEBUG_FREE)
5018                *p++ = 'F';
5019        if (!(s->flags & SLAB_NOTRACK))
5020                *p++ = 't';
5021        if (p != name + 1)
5022                *p++ = '-';
5023        p += sprintf(p, "%07d", s->size);
5024        BUG_ON(p > name + ID_STR_LENGTH - 1);
5025        return name;
5026}
5027
5028static int sysfs_slab_add(struct kmem_cache *s)
5029{
5030        int err;
5031        const char *name;
5032        int unmergeable;
5033
5034        if (slab_state < SYSFS)
5035                /* Defer until later */
5036                return 0;
5037
5038        unmergeable = slab_unmergeable(s);
5039        if (unmergeable) {
5040                /*
5041                 * Slabcache can never be merged so we can use the name proper.
5042                 * This is typically the case for debug situations. In that
5043                 * case we can catch duplicate names easily.
5044                 */
5045                sysfs_remove_link(&slab_kset->kobj, s->name);
5046                name = s->name;
5047        } else {
5048                /*
5049                 * Create a unique name for the slab as a target
5050                 * for the symlinks.
5051                 */
5052                name = create_unique_id(s);
5053        }
5054
5055        s->kobj.kset = slab_kset;
5056        err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
5057        if (err) {
5058                kobject_put(&s->kobj);
5059                return err;
5060        }
5061
5062        err = sysfs_create_group(&s->kobj, &slab_attr_group);
5063        if (err) {
5064                kobject_del(&s->kobj);
5065                kobject_put(&s->kobj);
5066                return err;
5067        }
5068        kobject_uevent(&s->kobj, KOBJ_ADD);
5069        if (!unmergeable) {
5070                /* Setup first alias */
5071                sysfs_slab_alias(s, s->name);
5072                kfree(name);
5073        }
5074        return 0;
5075}
5076
5077static void sysfs_slab_remove(struct kmem_cache *s)
5078{
5079        if (slab_state < SYSFS)
5080                /*
5081                 * Sysfs has not been setup yet so no need to remove the
5082                 * cache from sysfs.
5083                 */
5084                return;
5085
5086        kobject_uevent(&s->kobj, KOBJ_REMOVE);
5087        kobject_del(&s->kobj);
5088        kobject_put(&s->kobj);
5089}
5090
5091/*
5092 * Need to buffer aliases during bootup until sysfs becomes
5093 * available lest we lose that information.
5094 */
5095struct saved_alias {
5096        struct kmem_cache *s;
5097        const char *name;
5098        struct saved_alias *next;
5099};
5100
5101static struct saved_alias *alias_list;
5102
5103static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5104{
5105        struct saved_alias *al;
5106
5107        if (slab_state == SYSFS) {
5108                /*
5109                 * If we have a leftover link then remove it.
5110                 */
5111                sysfs_remove_link(&slab_kset->kobj, name);
5112                return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5113        }
5114
5115        al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5116        if (!al)
5117                return -ENOMEM;
5118
5119        al->s = s;
5120        al->name = name;
5121        al->next = alias_list;
5122        alias_list = al;
5123        return 0;
5124}
5125
5126static int __init slab_sysfs_init(void)
5127{
5128        struct kmem_cache *s;
5129        int err;
5130
5131        down_write(&slub_lock);
5132
5133        slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5134        if (!slab_kset) {
5135                up_write(&slub_lock);
5136                printk(KERN_ERR "Cannot register slab subsystem.\n");
5137                return -ENOSYS;
5138        }
5139
5140        slab_state = SYSFS;
5141
5142        list_for_each_entry(s, &slab_caches, list) {
5143                err = sysfs_slab_add(s);
5144                if (err)
5145                        printk(KERN_ERR "SLUB: Unable to add boot slab %s"
5146                                                " to sysfs\n", s->name);
5147        }
5148
5149        while (alias_list) {
5150                struct saved_alias *al = alias_list;
5151
5152                alias_list = alias_list->next;
5153                err = sysfs_slab_alias(al->s, al->name);
5154                if (err)
5155                        printk(KERN_ERR "SLUB: Unable to add boot slab alias"
5156                                        " %s to sysfs\n", s->name);
5157                kfree(al);
5158        }
5159
5160        up_write(&slub_lock);
5161        resiliency_test();
5162        return 0;
5163}
5164
5165__initcall(slab_sysfs_init);
5166#endif /* CONFIG_SYSFS */
5167
5168/*
5169 * The /proc/slabinfo ABI
5170 */
5171#ifdef CONFIG_SLABINFO
5172static void print_slabinfo_header(struct seq_file *m)
5173{
5174        seq_puts(m, "slabinfo - version: 2.1\n");
5175        seq_puts(m, "# name            <active_objs> <num_objs> <objsize> "
5176                 "<objperslab> <pagesperslab>");
5177        seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
5178        seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
5179        seq_putc(m, '\n');
5180}
5181
5182static void *s_start(struct seq_file *m, loff_t *pos)
5183{
5184        loff_t n = *pos;
5185
5186        down_read(&slub_lock);
5187        if (!n)
5188                print_slabinfo_header(m);
5189
5190        return seq_list_start(&slab_caches, *pos);
5191}
5192
5193static void *s_next(struct seq_file *m, void *p, loff_t *pos)
5194{
5195        return seq_list_next(p, &slab_caches, pos);
5196}
5197
5198static void s_stop(struct seq_file *m, void *p)
5199{
5200        up_read(&slub_lock);
5201}
5202
5203static int s_show(struct seq_file *m, void *p)
5204{
5205        unsigned long nr_partials = 0;
5206        unsigned long nr_slabs = 0;
5207        unsigned long nr_inuse = 0;
5208        unsigned long nr_objs = 0;
5209        unsigned long nr_free = 0;
5210        struct kmem_cache *s;
5211        int node;
5212
5213        s = list_entry(p, struct kmem_cache, list);
5214
5215        for_each_online_node(node) {
5216                struct kmem_cache_node *n = get_node(s, node);
5217
5218                if (!n)
5219                        continue;
5220
5221                nr_partials += n->nr_partial;
5222                nr_slabs += atomic_long_read(&n->nr_slabs);
5223                nr_objs += atomic_long_read(&n->total_objects);
5224                nr_free += count_partial(n, count_free);
5225        }
5226
5227        nr_inuse = nr_objs - nr_free;
5228
5229        seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
5230                   nr_objs, s->size, oo_objects(s->oo),
5231                   (1 << oo_order(s->oo)));
5232        seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
5233        seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
5234                   0UL);
5235        seq_putc(m, '\n');
5236        return 0;
5237}
5238
5239static const struct seq_operations slabinfo_op = {
5240        .start = s_start,
5241        .next = s_next,
5242        .stop = s_stop,
5243        .show = s_show,
5244};
5245
5246static int slabinfo_open(struct inode *inode, struct file *file)
5247{
5248        return seq_open(file, &slabinfo_op);
5249}
5250
5251static const struct file_operations proc_slabinfo_operations = {
5252        .open           = slabinfo_open,
5253        .read           = seq_read,
5254        .llseek         = seq_lseek,
5255        .release        = seq_release,
5256};
5257
5258static int __init slab_proc_init(void)
5259{
5260        proc_create("slabinfo", S_IRUGO, NULL, &proc_slabinfo_operations);
5261        return 0;
5262}
5263module_init(slab_proc_init);
5264#endif /* CONFIG_SLABINFO */
5265
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