Root/mm/slub.c

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 "slab.h"
20#include <linux/proc_fs.h>
21#include <linux/notifier.h>
22#include <linux/seq_file.h>
23#include <linux/kmemcheck.h>
24#include <linux/cpu.h>
25#include <linux/cpuset.h>
26#include <linux/mempolicy.h>
27#include <linux/ctype.h>
28#include <linux/debugobjects.h>
29#include <linux/kallsyms.h>
30#include <linux/memory.h>
31#include <linux/math64.h>
32#include <linux/fault-inject.h>
33#include <linux/stacktrace.h>
34#include <linux/prefetch.h>
35#include <linux/memcontrol.h>
36
37#include <trace/events/kmem.h>
38
39#include "internal.h"
40
41/*
42 * Lock order:
43 * 1. slab_mutex (Global Mutex)
44 * 2. node->list_lock
45 * 3. slab_lock(page) (Only on some arches and for debugging)
46 *
47 * slab_mutex
48 *
49 * The role of the slab_mutex is to protect the list of all the slabs
50 * and to synchronize major metadata changes to slab cache structures.
51 *
52 * The slab_lock is only used for debugging and on arches that do not
53 * have the ability to do a cmpxchg_double. It only protects the second
54 * double word in the page struct. Meaning
55 * A. page->freelist -> List of object free in a page
56 * B. page->counters -> Counters of objects
57 * C. page->frozen -> frozen state
58 *
59 * If a slab is frozen then it is exempt from list management. It is not
60 * on any list. The processor that froze the slab is the one who can
61 * perform list operations on the page. Other processors may put objects
62 * onto the freelist but the processor that froze the slab is the only
63 * one that can retrieve the objects from the page's freelist.
64 *
65 * The list_lock protects the partial and full list on each node and
66 * the partial slab counter. If taken then no new slabs may be added or
67 * removed from the lists nor make the number of partial slabs be modified.
68 * (Note that the total number of slabs is an atomic value that may be
69 * modified without taking the list lock).
70 *
71 * The list_lock is a centralized lock and thus we avoid taking it as
72 * much as possible. As long as SLUB does not have to handle partial
73 * slabs, operations can continue without any centralized lock. F.e.
74 * allocating a long series of objects that fill up slabs does not require
75 * the list lock.
76 * Interrupts are disabled during allocation and deallocation in order to
77 * make the slab allocator safe to use in the context of an irq. In addition
78 * interrupts are disabled to ensure that the processor does not change
79 * while handling per_cpu slabs, due to kernel preemption.
80 *
81 * SLUB assigns one slab for allocation to each processor.
82 * Allocations only occur from these slabs called cpu slabs.
83 *
84 * Slabs with free elements are kept on a partial list and during regular
85 * operations no list for full slabs is used. If an object in a full slab is
86 * freed then the slab will show up again on the partial lists.
87 * We track full slabs for debugging purposes though because otherwise we
88 * cannot scan all objects.
89 *
90 * Slabs are freed when they become empty. Teardown and setup is
91 * minimal so we rely on the page allocators per cpu caches for
92 * fast frees and allocs.
93 *
94 * Overloading of page flags that are otherwise used for LRU management.
95 *
96 * PageActive The slab is frozen and exempt from list processing.
97 * This means that the slab is dedicated to a purpose
98 * such as satisfying allocations for a specific
99 * processor. Objects may be freed in the slab while
100 * it is frozen but slab_free will then skip the usual
101 * list operations. It is up to the processor holding
102 * the slab to integrate the slab into the slab lists
103 * when the slab is no longer needed.
104 *
105 * One use of this flag is to mark slabs that are
106 * used for allocations. Then such a slab becomes a cpu
107 * slab. The cpu slab may be equipped with an additional
108 * freelist that allows lockless access to
109 * free objects in addition to the regular freelist
110 * that requires the slab lock.
111 *
112 * PageError Slab requires special handling due to debug
113 * options set. This moves slab handling out of
114 * the fast path and disables lockless freelists.
115 */
116
117static inline int kmem_cache_debug(struct kmem_cache *s)
118{
119#ifdef CONFIG_SLUB_DEBUG
120    return unlikely(s->flags & SLAB_DEBUG_FLAGS);
121#else
122    return 0;
123#endif
124}
125
126static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
127{
128#ifdef CONFIG_SLUB_CPU_PARTIAL
129    return !kmem_cache_debug(s);
130#else
131    return false;
132#endif
133}
134
135/*
136 * Issues still to be resolved:
137 *
138 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
139 *
140 * - Variable sizing of the per node arrays
141 */
142
143/* Enable to test recovery from slab corruption on boot */
144#undef SLUB_RESILIENCY_TEST
145
146/* Enable to log cmpxchg failures */
147#undef SLUB_DEBUG_CMPXCHG
148
149/*
150 * Mininum number of partial slabs. These will be left on the partial
151 * lists even if they are empty. kmem_cache_shrink may reclaim them.
152 */
153#define MIN_PARTIAL 5
154
155/*
156 * Maximum number of desirable partial slabs.
157 * The existence of more partial slabs makes kmem_cache_shrink
158 * sort the partial list by the number of objects in the.
159 */
160#define MAX_PARTIAL 10
161
162#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
163                SLAB_POISON | SLAB_STORE_USER)
164
165/*
166 * Debugging flags that require metadata to be stored in the slab. These get
167 * disabled when slub_debug=O is used and a cache's min order increases with
168 * metadata.
169 */
170#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
171
172/*
173 * Set of flags that will prevent slab merging
174 */
175#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
176        SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
177        SLAB_FAILSLAB)
178
179#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
180        SLAB_CACHE_DMA | SLAB_NOTRACK)
181
182#define OO_SHIFT 16
183#define OO_MASK ((1 << OO_SHIFT) - 1)
184#define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
185
186/* Internal SLUB flags */
187#define __OBJECT_POISON 0x80000000UL /* Poison object */
188#define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
189
190#ifdef CONFIG_SMP
191static struct notifier_block slab_notifier;
192#endif
193
194/*
195 * Tracking user of a slab.
196 */
197#define TRACK_ADDRS_COUNT 16
198struct track {
199    unsigned long addr; /* Called from address */
200#ifdef CONFIG_STACKTRACE
201    unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
202#endif
203    int cpu; /* Was running on cpu */
204    int pid; /* Pid context */
205    unsigned long when; /* When did the operation occur */
206};
207
208enum track_item { TRACK_ALLOC, TRACK_FREE };
209
210#ifdef CONFIG_SYSFS
211static int sysfs_slab_add(struct kmem_cache *);
212static int sysfs_slab_alias(struct kmem_cache *, const char *);
213static void sysfs_slab_remove(struct kmem_cache *);
214static void memcg_propagate_slab_attrs(struct kmem_cache *s);
215#else
216static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
217static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
218                            { return 0; }
219static inline void sysfs_slab_remove(struct kmem_cache *s) { }
220
221static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
222#endif
223
224static inline void stat(const struct kmem_cache *s, enum stat_item si)
225{
226#ifdef CONFIG_SLUB_STATS
227    __this_cpu_inc(s->cpu_slab->stat[si]);
228#endif
229}
230
231/********************************************************************
232 * Core slab cache functions
233 *******************************************************************/
234
235static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
236{
237    return s->node[node];
238}
239
240/* Verify that a pointer has an address that is valid within a slab page */
241static inline int check_valid_pointer(struct kmem_cache *s,
242                struct page *page, const void *object)
243{
244    void *base;
245
246    if (!object)
247        return 1;
248
249    base = page_address(page);
250    if (object < base || object >= base + page->objects * s->size ||
251        (object - base) % s->size) {
252        return 0;
253    }
254
255    return 1;
256}
257
258static inline void *get_freepointer(struct kmem_cache *s, void *object)
259{
260    return *(void **)(object + s->offset);
261}
262
263static void prefetch_freepointer(const struct kmem_cache *s, void *object)
264{
265    prefetch(object + s->offset);
266}
267
268static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
269{
270    void *p;
271
272#ifdef CONFIG_DEBUG_PAGEALLOC
273    probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
274#else
275    p = get_freepointer(s, object);
276#endif
277    return p;
278}
279
280static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
281{
282    *(void **)(object + s->offset) = fp;
283}
284
285/* Loop over all objects in a slab */
286#define for_each_object(__p, __s, __addr, __objects) \
287    for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
288            __p += (__s)->size)
289
290/* Determine object index from a given position */
291static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
292{
293    return (p - addr) / s->size;
294}
295
296static inline size_t slab_ksize(const struct kmem_cache *s)
297{
298#ifdef CONFIG_SLUB_DEBUG
299    /*
300     * Debugging requires use of the padding between object
301     * and whatever may come after it.
302     */
303    if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
304        return s->object_size;
305
306#endif
307    /*
308     * If we have the need to store the freelist pointer
309     * back there or track user information then we can
310     * only use the space before that information.
311     */
312    if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
313        return s->inuse;
314    /*
315     * Else we can use all the padding etc for the allocation
316     */
317    return s->size;
318}
319
320static inline int order_objects(int order, unsigned long size, int reserved)
321{
322    return ((PAGE_SIZE << order) - reserved) / size;
323}
324
325static inline struct kmem_cache_order_objects oo_make(int order,
326        unsigned long size, int reserved)
327{
328    struct kmem_cache_order_objects x = {
329        (order << OO_SHIFT) + order_objects(order, size, reserved)
330    };
331
332    return x;
333}
334
335static inline int oo_order(struct kmem_cache_order_objects x)
336{
337    return x.x >> OO_SHIFT;
338}
339
340static inline int oo_objects(struct kmem_cache_order_objects x)
341{
342    return x.x & OO_MASK;
343}
344
345/*
346 * Per slab locking using the pagelock
347 */
348static __always_inline void slab_lock(struct page *page)
349{
350    bit_spin_lock(PG_locked, &page->flags);
351}
352
353static __always_inline void slab_unlock(struct page *page)
354{
355    __bit_spin_unlock(PG_locked, &page->flags);
356}
357
358/* Interrupts must be disabled (for the fallback code to work right) */
359static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
360        void *freelist_old, unsigned long counters_old,
361        void *freelist_new, unsigned long counters_new,
362        const char *n)
363{
364    VM_BUG_ON(!irqs_disabled());
365#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
366    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
367    if (s->flags & __CMPXCHG_DOUBLE) {
368        if (cmpxchg_double(&page->freelist, &page->counters,
369            freelist_old, counters_old,
370            freelist_new, counters_new))
371        return 1;
372    } else
373#endif
374    {
375        slab_lock(page);
376        if (page->freelist == freelist_old &&
377                    page->counters == counters_old) {
378            page->freelist = freelist_new;
379            page->counters = counters_new;
380            slab_unlock(page);
381            return 1;
382        }
383        slab_unlock(page);
384    }
385
386    cpu_relax();
387    stat(s, CMPXCHG_DOUBLE_FAIL);
388
389#ifdef SLUB_DEBUG_CMPXCHG
390    printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
391#endif
392
393    return 0;
394}
395
396static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
397        void *freelist_old, unsigned long counters_old,
398        void *freelist_new, unsigned long counters_new,
399        const char *n)
400{
401#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
402    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
403    if (s->flags & __CMPXCHG_DOUBLE) {
404        if (cmpxchg_double(&page->freelist, &page->counters,
405            freelist_old, counters_old,
406            freelist_new, counters_new))
407        return 1;
408    } else
409#endif
410    {
411        unsigned long flags;
412
413        local_irq_save(flags);
414        slab_lock(page);
415        if (page->freelist == freelist_old &&
416                    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    print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
471            length, 1);
472}
473
474static struct track *get_track(struct kmem_cache *s, void *object,
475    enum track_item alloc)
476{
477    struct track *p;
478
479    if (s->offset)
480        p = object + s->offset + sizeof(void *);
481    else
482        p = object + s->inuse;
483
484    return p + alloc;
485}
486
487static void set_track(struct kmem_cache *s, void *object,
488            enum track_item alloc, unsigned long addr)
489{
490    struct track *p = get_track(s, object, alloc);
491
492    if (addr) {
493#ifdef CONFIG_STACKTRACE
494        struct stack_trace trace;
495        int i;
496
497        trace.nr_entries = 0;
498        trace.max_entries = TRACK_ADDRS_COUNT;
499        trace.entries = p->addrs;
500        trace.skip = 3;
501        save_stack_trace(&trace);
502
503        /* See rant in lockdep.c */
504        if (trace.nr_entries != 0 &&
505            trace.entries[trace.nr_entries - 1] == ULONG_MAX)
506            trace.nr_entries--;
507
508        for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
509            p->addrs[i] = 0;
510#endif
511        p->addr = addr;
512        p->cpu = smp_processor_id();
513        p->pid = current->pid;
514        p->when = jiffies;
515    } else
516        memset(p, 0, sizeof(struct track));
517}
518
519static void init_tracking(struct kmem_cache *s, void *object)
520{
521    if (!(s->flags & SLAB_STORE_USER))
522        return;
523
524    set_track(s, object, TRACK_FREE, 0UL);
525    set_track(s, object, TRACK_ALLOC, 0UL);
526}
527
528static void print_track(const char *s, struct track *t)
529{
530    if (!t->addr)
531        return;
532
533    printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
534        s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
535#ifdef CONFIG_STACKTRACE
536    {
537        int i;
538        for (i = 0; i < TRACK_ADDRS_COUNT; i++)
539            if (t->addrs[i])
540                printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
541            else
542                break;
543    }
544#endif
545}
546
547static void print_tracking(struct kmem_cache *s, void *object)
548{
549    if (!(s->flags & SLAB_STORE_USER))
550        return;
551
552    print_track("Allocated", get_track(s, object, TRACK_ALLOC));
553    print_track("Freed", get_track(s, object, TRACK_FREE));
554}
555
556static void print_page_info(struct page *page)
557{
558    printk(KERN_ERR
559           "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
560           page, page->objects, page->inuse, page->freelist, page->flags);
561
562}
563
564static void slab_bug(struct kmem_cache *s, char *fmt, ...)
565{
566    va_list args;
567    char buf[100];
568
569    va_start(args, fmt);
570    vsnprintf(buf, sizeof(buf), fmt, args);
571    va_end(args);
572    printk(KERN_ERR "========================================"
573            "=====================================\n");
574    printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
575    printk(KERN_ERR "----------------------------------------"
576            "-------------------------------------\n\n");
577
578    add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
579}
580
581static void slab_fix(struct kmem_cache *s, char *fmt, ...)
582{
583    va_list args;
584    char buf[100];
585
586    va_start(args, fmt);
587    vsnprintf(buf, sizeof(buf), fmt, args);
588    va_end(args);
589    printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
590}
591
592static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
593{
594    unsigned int off; /* Offset of last byte */
595    u8 *addr = page_address(page);
596
597    print_tracking(s, p);
598
599    print_page_info(page);
600
601    printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
602            p, p - addr, get_freepointer(s, p));
603
604    if (p > addr + 16)
605        print_section("Bytes b4 ", p - 16, 16);
606
607    print_section("Object ", p, min_t(unsigned long, s->object_size,
608                PAGE_SIZE));
609    if (s->flags & SLAB_RED_ZONE)
610        print_section("Redzone ", p + s->object_size,
611            s->inuse - s->object_size);
612
613    if (s->offset)
614        off = s->offset + sizeof(void *);
615    else
616        off = s->inuse;
617
618    if (s->flags & SLAB_STORE_USER)
619        off += 2 * sizeof(struct track);
620
621    if (off != s->size)
622        /* Beginning of the filler is the free pointer */
623        print_section("Padding ", p + off, s->size - off);
624
625    dump_stack();
626}
627
628static void object_err(struct kmem_cache *s, struct page *page,
629            u8 *object, char *reason)
630{
631    slab_bug(s, "%s", reason);
632    print_trailer(s, page, object);
633}
634
635static void slab_err(struct kmem_cache *s, struct page *page,
636            const char *fmt, ...)
637{
638    va_list args;
639    char buf[100];
640
641    va_start(args, fmt);
642    vsnprintf(buf, sizeof(buf), fmt, args);
643    va_end(args);
644    slab_bug(s, "%s", buf);
645    print_page_info(page);
646    dump_stack();
647}
648
649static void init_object(struct kmem_cache *s, void *object, u8 val)
650{
651    u8 *p = object;
652
653    if (s->flags & __OBJECT_POISON) {
654        memset(p, POISON_FREE, s->object_size - 1);
655        p[s->object_size - 1] = POISON_END;
656    }
657
658    if (s->flags & SLAB_RED_ZONE)
659        memset(p + s->object_size, val, s->inuse - s->object_size);
660}
661
662static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
663                        void *from, void *to)
664{
665    slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
666    memset(from, data, to - from);
667}
668
669static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
670            u8 *object, char *what,
671            u8 *start, unsigned int value, unsigned int bytes)
672{
673    u8 *fault;
674    u8 *end;
675
676    fault = memchr_inv(start, value, bytes);
677    if (!fault)
678        return 1;
679
680    end = start + bytes;
681    while (end > fault && end[-1] == value)
682        end--;
683
684    slab_bug(s, "%s overwritten", what);
685    printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
686                    fault, end - 1, fault[0], value);
687    print_trailer(s, page, object);
688
689    restore_bytes(s, what, value, fault, end);
690    return 0;
691}
692
693/*
694 * Object layout:
695 *
696 * object address
697 * Bytes of the object to be managed.
698 * If the freepointer may overlay the object then the free
699 * pointer is the first word of the object.
700 *
701 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
702 * 0xa5 (POISON_END)
703 *
704 * object + s->object_size
705 * Padding to reach word boundary. This is also used for Redzoning.
706 * Padding is extended by another word if Redzoning is enabled and
707 * object_size == inuse.
708 *
709 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
710 * 0xcc (RED_ACTIVE) for objects in use.
711 *
712 * object + s->inuse
713 * Meta data starts here.
714 *
715 * A. Free pointer (if we cannot overwrite object on free)
716 * B. Tracking data for SLAB_STORE_USER
717 * C. Padding to reach required alignment boundary or at mininum
718 * one word if debugging is on to be able to detect writes
719 * before the word boundary.
720 *
721 * Padding is done using 0x5a (POISON_INUSE)
722 *
723 * object + s->size
724 * Nothing is used beyond s->size.
725 *
726 * If slabcaches are merged then the object_size and inuse boundaries are mostly
727 * ignored. And therefore no slab options that rely on these boundaries
728 * may be used with merged slabcaches.
729 */
730
731static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
732{
733    unsigned long off = s->inuse; /* The end of info */
734
735    if (s->offset)
736        /* Freepointer is placed after the object. */
737        off += sizeof(void *);
738
739    if (s->flags & SLAB_STORE_USER)
740        /* We also have user information there */
741        off += 2 * sizeof(struct track);
742
743    if (s->size == off)
744        return 1;
745
746    return check_bytes_and_report(s, page, p, "Object padding",
747                p + off, POISON_INUSE, s->size - off);
748}
749
750/* Check the pad bytes at the end of a slab page */
751static int slab_pad_check(struct kmem_cache *s, struct page *page)
752{
753    u8 *start;
754    u8 *fault;
755    u8 *end;
756    int length;
757    int remainder;
758
759    if (!(s->flags & SLAB_POISON))
760        return 1;
761
762    start = page_address(page);
763    length = (PAGE_SIZE << compound_order(page)) - s->reserved;
764    end = start + length;
765    remainder = length % s->size;
766    if (!remainder)
767        return 1;
768
769    fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
770    if (!fault)
771        return 1;
772    while (end > fault && end[-1] == POISON_INUSE)
773        end--;
774
775    slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
776    print_section("Padding ", end - remainder, remainder);
777
778    restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
779    return 0;
780}
781
782static int check_object(struct kmem_cache *s, struct page *page,
783                    void *object, u8 val)
784{
785    u8 *p = object;
786    u8 *endobject = object + s->object_size;
787
788    if (s->flags & SLAB_RED_ZONE) {
789        if (!check_bytes_and_report(s, page, object, "Redzone",
790            endobject, val, s->inuse - s->object_size))
791            return 0;
792    } else {
793        if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
794            check_bytes_and_report(s, page, p, "Alignment padding",
795                endobject, POISON_INUSE,
796                s->inuse - s->object_size);
797        }
798    }
799
800    if (s->flags & SLAB_POISON) {
801        if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
802            (!check_bytes_and_report(s, page, p, "Poison", p,
803                    POISON_FREE, s->object_size - 1) ||
804             !check_bytes_and_report(s, page, p, "Poison",
805                p + s->object_size - 1, POISON_END, 1)))
806            return 0;
807        /*
808         * check_pad_bytes cleans up on its own.
809         */
810        check_pad_bytes(s, page, p);
811    }
812
813    if (!s->offset && val == SLUB_RED_ACTIVE)
814        /*
815         * Object and freepointer overlap. Cannot check
816         * freepointer while object is allocated.
817         */
818        return 1;
819
820    /* Check free pointer validity */
821    if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
822        object_err(s, page, p, "Freepointer corrupt");
823        /*
824         * No choice but to zap it and thus lose the remainder
825         * of the free objects in this slab. May cause
826         * another error because the object count is now wrong.
827         */
828        set_freepointer(s, p, NULL);
829        return 0;
830    }
831    return 1;
832}
833
834static int check_slab(struct kmem_cache *s, struct page *page)
835{
836    int maxobj;
837
838    VM_BUG_ON(!irqs_disabled());
839
840    if (!PageSlab(page)) {
841        slab_err(s, page, "Not a valid slab page");
842        return 0;
843    }
844
845    maxobj = order_objects(compound_order(page), s->size, s->reserved);
846    if (page->objects > maxobj) {
847        slab_err(s, page, "objects %u > max %u",
848            s->name, page->objects, maxobj);
849        return 0;
850    }
851    if (page->inuse > page->objects) {
852        slab_err(s, page, "inuse %u > max %u",
853            s->name, page->inuse, page->objects);
854        return 0;
855    }
856    /* Slab_pad_check fixes things up after itself */
857    slab_pad_check(s, page);
858    return 1;
859}
860
861/*
862 * Determine if a certain object on a page is on the freelist. Must hold the
863 * slab lock to guarantee that the chains are in a consistent state.
864 */
865static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
866{
867    int nr = 0;
868    void *fp;
869    void *object = NULL;
870    unsigned long max_objects;
871
872    fp = page->freelist;
873    while (fp && nr <= page->objects) {
874        if (fp == search)
875            return 1;
876        if (!check_valid_pointer(s, page, fp)) {
877            if (object) {
878                object_err(s, page, object,
879                    "Freechain corrupt");
880                set_freepointer(s, object, NULL);
881            } else {
882                slab_err(s, page, "Freepointer corrupt");
883                page->freelist = NULL;
884                page->inuse = page->objects;
885                slab_fix(s, "Freelist cleared");
886                return 0;
887            }
888            break;
889        }
890        object = fp;
891        fp = get_freepointer(s, object);
892        nr++;
893    }
894
895    max_objects = order_objects(compound_order(page), s->size, s->reserved);
896    if (max_objects > MAX_OBJS_PER_PAGE)
897        max_objects = MAX_OBJS_PER_PAGE;
898
899    if (page->objects != max_objects) {
900        slab_err(s, page, "Wrong number of objects. Found %d but "
901            "should be %d", page->objects, max_objects);
902        page->objects = max_objects;
903        slab_fix(s, "Number of objects adjusted.");
904    }
905    if (page->inuse != page->objects - nr) {
906        slab_err(s, page, "Wrong object count. Counter is %d but "
907            "counted were %d", page->inuse, page->objects - nr);
908        page->inuse = page->objects - nr;
909        slab_fix(s, "Object count adjusted.");
910    }
911    return search == NULL;
912}
913
914static void trace(struct kmem_cache *s, struct page *page, void *object,
915                                int alloc)
916{
917    if (s->flags & SLAB_TRACE) {
918        printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
919            s->name,
920            alloc ? "alloc" : "free",
921            object, page->inuse,
922            page->freelist);
923
924        if (!alloc)
925            print_section("Object ", (void *)object,
926                    s->object_size);
927
928        dump_stack();
929    }
930}
931
932/*
933 * Hooks for other subsystems that check memory allocations. In a typical
934 * production configuration these hooks all should produce no code at all.
935 */
936static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
937{
938    flags &= gfp_allowed_mask;
939    lockdep_trace_alloc(flags);
940    might_sleep_if(flags & __GFP_WAIT);
941
942    return should_failslab(s->object_size, flags, s->flags);
943}
944
945static inline void slab_post_alloc_hook(struct kmem_cache *s,
946                    gfp_t flags, void *object)
947{
948    flags &= gfp_allowed_mask;
949    kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
950    kmemleak_alloc_recursive(object, s->object_size, 1, s->flags, flags);
951}
952
953static inline void slab_free_hook(struct kmem_cache *s, void *x)
954{
955    kmemleak_free_recursive(x, s->flags);
956
957    /*
958     * Trouble is that we may no longer disable interupts in the fast path
959     * So in order to make the debug calls that expect irqs to be
960     * disabled we need to disable interrupts temporarily.
961     */
962#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
963    {
964        unsigned long flags;
965
966        local_irq_save(flags);
967        kmemcheck_slab_free(s, x, s->object_size);
968        debug_check_no_locks_freed(x, s->object_size);
969        local_irq_restore(flags);
970    }
971#endif
972    if (!(s->flags & SLAB_DEBUG_OBJECTS))
973        debug_check_no_obj_freed(x, s->object_size);
974}
975
976/*
977 * Tracking of fully allocated slabs for debugging purposes.
978 *
979 * list_lock must be held.
980 */
981static void add_full(struct kmem_cache *s,
982    struct kmem_cache_node *n, struct page *page)
983{
984    if (!(s->flags & SLAB_STORE_USER))
985        return;
986
987    list_add(&page->lru, &n->full);
988}
989
990/*
991 * list_lock must be held.
992 */
993static void remove_full(struct kmem_cache *s, struct page *page)
994{
995    if (!(s->flags & SLAB_STORE_USER))
996        return;
997
998    list_del(&page->lru);
999}
1000
1001/* Tracking of the number of slabs for debugging purposes */
1002static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1003{
1004    struct kmem_cache_node *n = get_node(s, node);
1005
1006    return atomic_long_read(&n->nr_slabs);
1007}
1008
1009static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1010{
1011    return atomic_long_read(&n->nr_slabs);
1012}
1013
1014static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1015{
1016    struct kmem_cache_node *n = get_node(s, node);
1017
1018    /*
1019     * May be called early in order to allocate a slab for the
1020     * kmem_cache_node structure. Solve the chicken-egg
1021     * dilemma by deferring the increment of the count during
1022     * bootstrap (see early_kmem_cache_node_alloc).
1023     */
1024    if (likely(n)) {
1025        atomic_long_inc(&n->nr_slabs);
1026        atomic_long_add(objects, &n->total_objects);
1027    }
1028}
1029static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1030{
1031    struct kmem_cache_node *n = get_node(s, node);
1032
1033    atomic_long_dec(&n->nr_slabs);
1034    atomic_long_sub(objects, &n->total_objects);
1035}
1036
1037/* Object debug checks for alloc/free paths */
1038static void setup_object_debug(struct kmem_cache *s, struct page *page,
1039                                void *object)
1040{
1041    if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1042        return;
1043
1044    init_object(s, object, SLUB_RED_INACTIVE);
1045    init_tracking(s, object);
1046}
1047
1048static noinline int alloc_debug_processing(struct kmem_cache *s,
1049                    struct page *page,
1050                    void *object, unsigned long addr)
1051{
1052    if (!check_slab(s, page))
1053        goto bad;
1054
1055    if (!check_valid_pointer(s, page, object)) {
1056        object_err(s, page, object, "Freelist Pointer check fails");
1057        goto bad;
1058    }
1059
1060    if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1061        goto bad;
1062
1063    /* Success perform special debug activities for allocs */
1064    if (s->flags & SLAB_STORE_USER)
1065        set_track(s, object, TRACK_ALLOC, addr);
1066    trace(s, page, object, 1);
1067    init_object(s, object, SLUB_RED_ACTIVE);
1068    return 1;
1069
1070bad:
1071    if (PageSlab(page)) {
1072        /*
1073         * If this is a slab page then lets do the best we can
1074         * to avoid issues in the future. Marking all objects
1075         * as used avoids touching the remaining objects.
1076         */
1077        slab_fix(s, "Marking all objects used");
1078        page->inuse = page->objects;
1079        page->freelist = NULL;
1080    }
1081    return 0;
1082}
1083
1084static noinline struct kmem_cache_node *free_debug_processing(
1085    struct kmem_cache *s, struct page *page, void *object,
1086    unsigned long addr, unsigned long *flags)
1087{
1088    struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1089
1090    spin_lock_irqsave(&n->list_lock, *flags);
1091    slab_lock(page);
1092
1093    if (!check_slab(s, page))
1094        goto fail;
1095
1096    if (!check_valid_pointer(s, page, object)) {
1097        slab_err(s, page, "Invalid object pointer 0x%p", object);
1098        goto fail;
1099    }
1100
1101    if (on_freelist(s, page, object)) {
1102        object_err(s, page, object, "Object already free");
1103        goto fail;
1104    }
1105
1106    if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1107        goto out;
1108
1109    if (unlikely(s != page->slab_cache)) {
1110        if (!PageSlab(page)) {
1111            slab_err(s, page, "Attempt to free object(0x%p) "
1112                "outside of slab", object);
1113        } else if (!page->slab_cache) {
1114            printk(KERN_ERR
1115                "SLUB <none>: no slab for object 0x%p.\n",
1116                        object);
1117            dump_stack();
1118        } else
1119            object_err(s, page, object,
1120                    "page slab pointer corrupt.");
1121        goto fail;
1122    }
1123
1124    if (s->flags & SLAB_STORE_USER)
1125        set_track(s, object, TRACK_FREE, addr);
1126    trace(s, page, object, 0);
1127    init_object(s, object, SLUB_RED_INACTIVE);
1128out:
1129    slab_unlock(page);
1130    /*
1131     * Keep node_lock to preserve integrity
1132     * until the object is actually freed
1133     */
1134    return n;
1135
1136fail:
1137    slab_unlock(page);
1138    spin_unlock_irqrestore(&n->list_lock, *flags);
1139    slab_fix(s, "Object at 0x%p not freed", object);
1140    return NULL;
1141}
1142
1143static int __init setup_slub_debug(char *str)
1144{
1145    slub_debug = DEBUG_DEFAULT_FLAGS;
1146    if (*str++ != '=' || !*str)
1147        /*
1148         * No options specified. Switch on full debugging.
1149         */
1150        goto out;
1151
1152    if (*str == ',')
1153        /*
1154         * No options but restriction on slabs. This means full
1155         * debugging for slabs matching a pattern.
1156         */
1157        goto check_slabs;
1158
1159    if (tolower(*str) == 'o') {
1160        /*
1161         * Avoid enabling debugging on caches if its minimum order
1162         * would increase as a result.
1163         */
1164        disable_higher_order_debug = 1;
1165        goto out;
1166    }
1167
1168    slub_debug = 0;
1169    if (*str == '-')
1170        /*
1171         * Switch off all debugging measures.
1172         */
1173        goto out;
1174
1175    /*
1176     * Determine which debug features should be switched on
1177     */
1178    for (; *str && *str != ','; str++) {
1179        switch (tolower(*str)) {
1180        case 'f':
1181            slub_debug |= SLAB_DEBUG_FREE;
1182            break;
1183        case 'z':
1184            slub_debug |= SLAB_RED_ZONE;
1185            break;
1186        case 'p':
1187            slub_debug |= SLAB_POISON;
1188            break;
1189        case 'u':
1190            slub_debug |= SLAB_STORE_USER;
1191            break;
1192        case 't':
1193            slub_debug |= SLAB_TRACE;
1194            break;
1195        case 'a':
1196            slub_debug |= SLAB_FAILSLAB;
1197            break;
1198        default:
1199            printk(KERN_ERR "slub_debug option '%c' "
1200                "unknown. skipped\n", *str);
1201        }
1202    }
1203
1204check_slabs:
1205    if (*str == ',')
1206        slub_debug_slabs = str + 1;
1207out:
1208    return 1;
1209}
1210
1211__setup("slub_debug", setup_slub_debug);
1212
1213static unsigned long kmem_cache_flags(unsigned long object_size,
1214    unsigned long flags, const char *name,
1215    void (*ctor)(void *))
1216{
1217    /*
1218     * Enable debugging if selected on the kernel commandline.
1219     */
1220    if (slub_debug && (!slub_debug_slabs ||
1221        !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
1222        flags |= slub_debug;
1223
1224    return flags;
1225}
1226#else
1227static inline void setup_object_debug(struct kmem_cache *s,
1228            struct page *page, void *object) {}
1229
1230static inline int alloc_debug_processing(struct kmem_cache *s,
1231    struct page *page, void *object, unsigned long addr) { return 0; }
1232
1233static inline struct kmem_cache_node *free_debug_processing(
1234    struct kmem_cache *s, struct page *page, void *object,
1235    unsigned long addr, unsigned long *flags) { return NULL; }
1236
1237static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1238            { return 1; }
1239static inline int check_object(struct kmem_cache *s, struct page *page,
1240            void *object, u8 val) { return 1; }
1241static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1242                    struct page *page) {}
1243static inline void remove_full(struct kmem_cache *s, struct page *page) {}
1244static inline unsigned long kmem_cache_flags(unsigned long object_size,
1245    unsigned long flags, const char *name,
1246    void (*ctor)(void *))
1247{
1248    return flags;
1249}
1250#define slub_debug 0
1251
1252#define disable_higher_order_debug 0
1253
1254static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1255                            { return 0; }
1256static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1257                            { return 0; }
1258static inline void inc_slabs_node(struct kmem_cache *s, int node,
1259                            int objects) {}
1260static inline void dec_slabs_node(struct kmem_cache *s, int node,
1261                            int objects) {}
1262
1263static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1264                            { return 0; }
1265
1266static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
1267        void *object) {}
1268
1269static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
1270
1271#endif /* CONFIG_SLUB_DEBUG */
1272
1273/*
1274 * Slab allocation and freeing
1275 */
1276static inline struct page *alloc_slab_page(gfp_t flags, int node,
1277                    struct kmem_cache_order_objects oo)
1278{
1279    int order = oo_order(oo);
1280
1281    flags |= __GFP_NOTRACK;
1282
1283    if (node == NUMA_NO_NODE)
1284        return alloc_pages(flags, order);
1285    else
1286        return alloc_pages_exact_node(node, flags, order);
1287}
1288
1289static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1290{
1291    struct page *page;
1292    struct kmem_cache_order_objects oo = s->oo;
1293    gfp_t alloc_gfp;
1294
1295    flags &= gfp_allowed_mask;
1296
1297    if (flags & __GFP_WAIT)
1298        local_irq_enable();
1299
1300    flags |= s->allocflags;
1301
1302    /*
1303     * Let the initial higher-order allocation fail under memory pressure
1304     * so we fall-back to the minimum order allocation.
1305     */
1306    alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1307
1308    page = alloc_slab_page(alloc_gfp, node, oo);
1309    if (unlikely(!page)) {
1310        oo = s->min;
1311        /*
1312         * Allocation may have failed due to fragmentation.
1313         * Try a lower order alloc if possible
1314         */
1315        page = alloc_slab_page(flags, node, oo);
1316
1317        if (page)
1318            stat(s, ORDER_FALLBACK);
1319    }
1320
1321    if (kmemcheck_enabled && page
1322        && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1323        int pages = 1 << oo_order(oo);
1324
1325        kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
1326
1327        /*
1328         * Objects from caches that have a constructor don't get
1329         * cleared when they're allocated, so we need to do it here.
1330         */
1331        if (s->ctor)
1332            kmemcheck_mark_uninitialized_pages(page, pages);
1333        else
1334            kmemcheck_mark_unallocated_pages(page, pages);
1335    }
1336
1337    if (flags & __GFP_WAIT)
1338        local_irq_disable();
1339    if (!page)
1340        return NULL;
1341
1342    page->objects = oo_objects(oo);
1343    mod_zone_page_state(page_zone(page),
1344        (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1345        NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1346        1 << oo_order(oo));
1347
1348    return page;
1349}
1350
1351static void setup_object(struct kmem_cache *s, struct page *page,
1352                void *object)
1353{
1354    setup_object_debug(s, page, object);
1355    if (unlikely(s->ctor))
1356        s->ctor(object);
1357}
1358
1359static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1360{
1361    struct page *page;
1362    void *start;
1363    void *last;
1364    void *p;
1365    int order;
1366
1367    BUG_ON(flags & GFP_SLAB_BUG_MASK);
1368
1369    page = allocate_slab(s,
1370        flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1371    if (!page)
1372        goto out;
1373
1374    order = compound_order(page);
1375    inc_slabs_node(s, page_to_nid(page), page->objects);
1376    memcg_bind_pages(s, order);
1377    page->slab_cache = s;
1378    __SetPageSlab(page);
1379    if (page->pfmemalloc)
1380        SetPageSlabPfmemalloc(page);
1381
1382    start = page_address(page);
1383
1384    if (unlikely(s->flags & SLAB_POISON))
1385        memset(start, POISON_INUSE, PAGE_SIZE << order);
1386
1387    last = start;
1388    for_each_object(p, s, start, page->objects) {
1389        setup_object(s, page, last);
1390        set_freepointer(s, last, p);
1391        last = p;
1392    }
1393    setup_object(s, page, last);
1394    set_freepointer(s, last, NULL);
1395
1396    page->freelist = start;
1397    page->inuse = page->objects;
1398    page->frozen = 1;
1399out:
1400    return page;
1401}
1402
1403static void __free_slab(struct kmem_cache *s, struct page *page)
1404{
1405    int order = compound_order(page);
1406    int pages = 1 << order;
1407
1408    if (kmem_cache_debug(s)) {
1409        void *p;
1410
1411        slab_pad_check(s, page);
1412        for_each_object(p, s, page_address(page),
1413                        page->objects)
1414            check_object(s, page, p, SLUB_RED_INACTIVE);
1415    }
1416
1417    kmemcheck_free_shadow(page, compound_order(page));
1418
1419    mod_zone_page_state(page_zone(page),
1420        (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1421        NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1422        -pages);
1423
1424    __ClearPageSlabPfmemalloc(page);
1425    __ClearPageSlab(page);
1426
1427    memcg_release_pages(s, order);
1428    page_mapcount_reset(page);
1429    if (current->reclaim_state)
1430        current->reclaim_state->reclaimed_slab += pages;
1431    __free_memcg_kmem_pages(page, order);
1432}
1433
1434#define need_reserve_slab_rcu \
1435    (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1436
1437static void rcu_free_slab(struct rcu_head *h)
1438{
1439    struct page *page;
1440
1441    if (need_reserve_slab_rcu)
1442        page = virt_to_head_page(h);
1443    else
1444        page = container_of((struct list_head *)h, struct page, lru);
1445
1446    __free_slab(page->slab_cache, page);
1447}
1448
1449static void free_slab(struct kmem_cache *s, struct page *page)
1450{
1451    if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1452        struct rcu_head *head;
1453
1454        if (need_reserve_slab_rcu) {
1455            int order = compound_order(page);
1456            int offset = (PAGE_SIZE << order) - s->reserved;
1457
1458            VM_BUG_ON(s->reserved != sizeof(*head));
1459            head = page_address(page) + offset;
1460        } else {
1461            /*
1462             * RCU free overloads the RCU head over the LRU
1463             */
1464            head = (void *)&page->lru;
1465        }
1466
1467        call_rcu(head, rcu_free_slab);
1468    } else
1469        __free_slab(s, page);
1470}
1471
1472static void discard_slab(struct kmem_cache *s, struct page *page)
1473{
1474    dec_slabs_node(s, page_to_nid(page), page->objects);
1475    free_slab(s, page);
1476}
1477
1478/*
1479 * Management of partially allocated slabs.
1480 *
1481 * list_lock must be held.
1482 */
1483static inline void add_partial(struct kmem_cache_node *n,
1484                struct page *page, int tail)
1485{
1486    n->nr_partial++;
1487    if (tail == DEACTIVATE_TO_TAIL)
1488        list_add_tail(&page->lru, &n->partial);
1489    else
1490        list_add(&page->lru, &n->partial);
1491}
1492
1493/*
1494 * list_lock must be held.
1495 */
1496static inline void remove_partial(struct kmem_cache_node *n,
1497                    struct page *page)
1498{
1499    list_del(&page->lru);
1500    n->nr_partial--;
1501}
1502
1503/*
1504 * Remove slab from the partial list, freeze it and
1505 * return the pointer to the freelist.
1506 *
1507 * Returns a list of objects or NULL if it fails.
1508 *
1509 * Must hold list_lock since we modify the partial list.
1510 */
1511static inline void *acquire_slab(struct kmem_cache *s,
1512        struct kmem_cache_node *n, struct page *page,
1513        int mode, int *objects)
1514{
1515    void *freelist;
1516    unsigned long counters;
1517    struct page new;
1518
1519    /*
1520     * Zap the freelist and set the frozen bit.
1521     * The old freelist is the list of objects for the
1522     * per cpu allocation list.
1523     */
1524    freelist = page->freelist;
1525    counters = page->counters;
1526    new.counters = counters;
1527    *objects = new.objects - new.inuse;
1528    if (mode) {
1529        new.inuse = page->objects;
1530        new.freelist = NULL;
1531    } else {
1532        new.freelist = freelist;
1533    }
1534
1535    VM_BUG_ON(new.frozen);
1536    new.frozen = 1;
1537
1538    if (!__cmpxchg_double_slab(s, page,
1539            freelist, counters,
1540            new.freelist, new.counters,
1541            "acquire_slab"))
1542        return NULL;
1543
1544    remove_partial(n, page);
1545    WARN_ON(!freelist);
1546    return freelist;
1547}
1548
1549static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1550static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1551
1552/*
1553 * Try to allocate a partial slab from a specific node.
1554 */
1555static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1556                struct kmem_cache_cpu *c, gfp_t flags)
1557{
1558    struct page *page, *page2;
1559    void *object = NULL;
1560    int available = 0;
1561    int objects;
1562
1563    /*
1564     * Racy check. If we mistakenly see no partial slabs then we
1565     * just allocate an empty slab. If we mistakenly try to get a
1566     * partial slab and there is none available then get_partials()
1567     * will return NULL.
1568     */
1569    if (!n || !n->nr_partial)
1570        return NULL;
1571
1572    spin_lock(&n->list_lock);
1573    list_for_each_entry_safe(page, page2, &n->partial, lru) {
1574        void *t;
1575
1576        if (!pfmemalloc_match(page, flags))
1577            continue;
1578
1579        t = acquire_slab(s, n, page, object == NULL, &objects);
1580        if (!t)
1581            break;
1582
1583        available += objects;
1584        if (!object) {
1585            c->page = page;
1586            stat(s, ALLOC_FROM_PARTIAL);
1587            object = t;
1588        } else {
1589            put_cpu_partial(s, page, 0);
1590            stat(s, CPU_PARTIAL_NODE);
1591        }
1592        if (!kmem_cache_has_cpu_partial(s)
1593            || available > s->cpu_partial / 2)
1594            break;
1595
1596    }
1597    spin_unlock(&n->list_lock);
1598    return object;
1599}
1600
1601/*
1602 * Get a page from somewhere. Search in increasing NUMA distances.
1603 */
1604static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1605        struct kmem_cache_cpu *c)
1606{
1607#ifdef CONFIG_NUMA
1608    struct zonelist *zonelist;
1609    struct zoneref *z;
1610    struct zone *zone;
1611    enum zone_type high_zoneidx = gfp_zone(flags);
1612    void *object;
1613    unsigned int cpuset_mems_cookie;
1614
1615    /*
1616     * The defrag ratio allows a configuration of the tradeoffs between
1617     * inter node defragmentation and node local allocations. A lower
1618     * defrag_ratio increases the tendency to do local allocations
1619     * instead of attempting to obtain partial slabs from other nodes.
1620     *
1621     * If the defrag_ratio is set to 0 then kmalloc() always
1622     * returns node local objects. If the ratio is higher then kmalloc()
1623     * may return off node objects because partial slabs are obtained
1624     * from other nodes and filled up.
1625     *
1626     * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1627     * defrag_ratio = 1000) then every (well almost) allocation will
1628     * first attempt to defrag slab caches on other nodes. This means
1629     * scanning over all nodes to look for partial slabs which may be
1630     * expensive if we do it every time we are trying to find a slab
1631     * with available objects.
1632     */
1633    if (!s->remote_node_defrag_ratio ||
1634            get_cycles() % 1024 > s->remote_node_defrag_ratio)
1635        return NULL;
1636
1637    do {
1638        cpuset_mems_cookie = get_mems_allowed();
1639        zonelist = node_zonelist(slab_node(), flags);
1640        for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1641            struct kmem_cache_node *n;
1642
1643            n = get_node(s, zone_to_nid(zone));
1644
1645            if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1646                    n->nr_partial > s->min_partial) {
1647                object = get_partial_node(s, n, c, flags);
1648                if (object) {
1649                    /*
1650                     * Return the object even if
1651                     * put_mems_allowed indicated that
1652                     * the cpuset mems_allowed was
1653                     * updated in parallel. It's a
1654                     * harmless race between the alloc
1655                     * and the cpuset update.
1656                     */
1657                    put_mems_allowed(cpuset_mems_cookie);
1658                    return object;
1659                }
1660            }
1661        }
1662    } while (!put_mems_allowed(cpuset_mems_cookie));
1663#endif
1664    return NULL;
1665}
1666
1667/*
1668 * Get a partial page, lock it and return it.
1669 */
1670static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1671        struct kmem_cache_cpu *c)
1672{
1673    void *object;
1674    int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
1675
1676    object = get_partial_node(s, get_node(s, searchnode), c, flags);
1677    if (object || node != NUMA_NO_NODE)
1678        return object;
1679
1680    return get_any_partial(s, flags, c);
1681}
1682
1683#ifdef CONFIG_PREEMPT
1684/*
1685 * Calculate the next globally unique transaction for disambiguiation
1686 * during cmpxchg. The transactions start with the cpu number and are then
1687 * incremented by CONFIG_NR_CPUS.
1688 */
1689#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1690#else
1691/*
1692 * No preemption supported therefore also no need to check for
1693 * different cpus.
1694 */
1695#define TID_STEP 1
1696#endif
1697
1698static inline unsigned long next_tid(unsigned long tid)
1699{
1700    return tid + TID_STEP;
1701}
1702
1703static inline unsigned int tid_to_cpu(unsigned long tid)
1704{
1705    return tid % TID_STEP;
1706}
1707
1708static inline unsigned long tid_to_event(unsigned long tid)
1709{
1710    return tid / TID_STEP;
1711}
1712
1713static inline unsigned int init_tid(int cpu)
1714{
1715    return cpu;
1716}
1717
1718static inline void note_cmpxchg_failure(const char *n,
1719        const struct kmem_cache *s, unsigned long tid)
1720{
1721#ifdef SLUB_DEBUG_CMPXCHG
1722    unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1723
1724    printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
1725
1726#ifdef CONFIG_PREEMPT
1727    if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1728        printk("due to cpu change %d -> %d\n",
1729            tid_to_cpu(tid), tid_to_cpu(actual_tid));
1730    else
1731#endif
1732    if (tid_to_event(tid) != tid_to_event(actual_tid))
1733        printk("due to cpu running other code. Event %ld->%ld\n",
1734            tid_to_event(tid), tid_to_event(actual_tid));
1735    else
1736        printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1737            actual_tid, tid, next_tid(tid));
1738#endif
1739    stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1740}
1741
1742static void init_kmem_cache_cpus(struct kmem_cache *s)
1743{
1744    int cpu;
1745
1746    for_each_possible_cpu(cpu)
1747        per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1748}
1749
1750/*
1751 * Remove the cpu slab
1752 */
1753static void deactivate_slab(struct kmem_cache *s, struct page *page,
1754                void *freelist)
1755{
1756    enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1757    struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1758    int lock = 0;
1759    enum slab_modes l = M_NONE, m = M_NONE;
1760    void *nextfree;
1761    int tail = DEACTIVATE_TO_HEAD;
1762    struct page new;
1763    struct page old;
1764
1765    if (page->freelist) {
1766        stat(s, DEACTIVATE_REMOTE_FREES);
1767        tail = DEACTIVATE_TO_TAIL;
1768    }
1769
1770    /*
1771     * Stage one: Free all available per cpu objects back
1772     * to the page freelist while it is still frozen. Leave the
1773     * last one.
1774     *
1775     * There is no need to take the list->lock because the page
1776     * is still frozen.
1777     */
1778    while (freelist && (nextfree = get_freepointer(s, freelist))) {
1779        void *prior;
1780        unsigned long counters;
1781
1782        do {
1783            prior = page->freelist;
1784            counters = page->counters;
1785            set_freepointer(s, freelist, prior);
1786            new.counters = counters;
1787            new.inuse--;
1788            VM_BUG_ON(!new.frozen);
1789
1790        } while (!__cmpxchg_double_slab(s, page,
1791            prior, counters,
1792            freelist, new.counters,
1793            "drain percpu freelist"));
1794
1795        freelist = nextfree;
1796    }
1797
1798    /*
1799     * Stage two: Ensure that the page is unfrozen while the
1800     * list presence reflects the actual number of objects
1801     * during unfreeze.
1802     *
1803     * We setup the list membership and then perform a cmpxchg
1804     * with the count. If there is a mismatch then the page
1805     * is not unfrozen but the page is on the wrong list.
1806     *
1807     * Then we restart the process which may have to remove
1808     * the page from the list that we just put it on again
1809     * because the number of objects in the slab may have
1810     * changed.
1811     */
1812redo:
1813
1814    old.freelist = page->freelist;
1815    old.counters = page->counters;
1816    VM_BUG_ON(!old.frozen);
1817
1818    /* Determine target state of the slab */
1819    new.counters = old.counters;
1820    if (freelist) {
1821        new.inuse--;
1822        set_freepointer(s, freelist, old.freelist);
1823        new.freelist = freelist;
1824    } else
1825        new.freelist = old.freelist;
1826
1827    new.frozen = 0;
1828
1829    if (!new.inuse && n->nr_partial > s->min_partial)
1830        m = M_FREE;
1831    else if (new.freelist) {
1832        m = M_PARTIAL;
1833        if (!lock) {
1834            lock = 1;
1835            /*
1836             * Taking the spinlock removes the possiblity
1837             * that acquire_slab() will see a slab page that
1838             * is frozen
1839             */
1840            spin_lock(&n->list_lock);
1841        }
1842    } else {
1843        m = M_FULL;
1844        if (kmem_cache_debug(s) && !lock) {
1845            lock = 1;
1846            /*
1847             * This also ensures that the scanning of full
1848             * slabs from diagnostic functions will not see
1849             * any frozen slabs.
1850             */
1851            spin_lock(&n->list_lock);
1852        }
1853    }
1854
1855    if (l != m) {
1856
1857        if (l == M_PARTIAL)
1858
1859            remove_partial(n, page);
1860
1861        else if (l == M_FULL)
1862
1863            remove_full(s, page);
1864
1865        if (m == M_PARTIAL) {
1866
1867            add_partial(n, page, tail);
1868            stat(s, tail);
1869
1870        } else if (m == M_FULL) {
1871
1872            stat(s, DEACTIVATE_FULL);
1873            add_full(s, n, page);
1874
1875        }
1876    }
1877
1878    l = m;
1879    if (!__cmpxchg_double_slab(s, page,
1880                old.freelist, old.counters,
1881                new.freelist, new.counters,
1882                "unfreezing slab"))
1883        goto redo;
1884
1885    if (lock)
1886        spin_unlock(&n->list_lock);
1887
1888    if (m == M_FREE) {
1889        stat(s, DEACTIVATE_EMPTY);
1890        discard_slab(s, page);
1891        stat(s, FREE_SLAB);
1892    }
1893}
1894
1895/*
1896 * Unfreeze all the cpu partial slabs.
1897 *
1898 * This function must be called with interrupts disabled
1899 * for the cpu using c (or some other guarantee must be there
1900 * to guarantee no concurrent accesses).
1901 */
1902static void unfreeze_partials(struct kmem_cache *s,
1903        struct kmem_cache_cpu *c)
1904{
1905#ifdef CONFIG_SLUB_CPU_PARTIAL
1906    struct kmem_cache_node *n = NULL, *n2 = NULL;
1907    struct page *page, *discard_page = NULL;
1908
1909    while ((page = c->partial)) {
1910        struct page new;
1911        struct page old;
1912
1913        c->partial = page->next;
1914
1915        n2 = get_node(s, page_to_nid(page));
1916        if (n != n2) {
1917            if (n)
1918                spin_unlock(&n->list_lock);
1919
1920            n = n2;
1921            spin_lock(&n->list_lock);
1922        }
1923
1924        do {
1925
1926            old.freelist = page->freelist;
1927            old.counters = page->counters;
1928            VM_BUG_ON(!old.frozen);
1929
1930            new.counters = old.counters;
1931            new.freelist = old.freelist;
1932
1933            new.frozen = 0;
1934
1935        } while (!__cmpxchg_double_slab(s, page,
1936                old.freelist, old.counters,
1937                new.freelist, new.counters,
1938                "unfreezing slab"));
1939
1940        if (unlikely(!new.inuse && n->nr_partial > s->min_partial)) {
1941            page->next = discard_page;
1942            discard_page = page;
1943        } else {
1944            add_partial(n, page, DEACTIVATE_TO_TAIL);
1945            stat(s, FREE_ADD_PARTIAL);
1946        }
1947    }
1948
1949    if (n)
1950        spin_unlock(&n->list_lock);
1951
1952    while (discard_page) {
1953        page = discard_page;
1954        discard_page = discard_page->next;
1955
1956        stat(s, DEACTIVATE_EMPTY);
1957        discard_slab(s, page);
1958        stat(s, FREE_SLAB);
1959    }
1960#endif
1961}
1962
1963/*
1964 * Put a page that was just frozen (in __slab_free) into a partial page
1965 * slot if available. This is done without interrupts disabled and without
1966 * preemption disabled. The cmpxchg is racy and may put the partial page
1967 * onto a random cpus partial slot.
1968 *
1969 * If we did not find a slot then simply move all the partials to the
1970 * per node partial list.
1971 */
1972static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
1973{
1974#ifdef CONFIG_SLUB_CPU_PARTIAL
1975    struct page *oldpage;
1976    int pages;
1977    int pobjects;
1978
1979    do {
1980        pages = 0;
1981        pobjects = 0;
1982        oldpage = this_cpu_read(s->cpu_slab->partial);
1983
1984        if (oldpage) {
1985            pobjects = oldpage->pobjects;
1986            pages = oldpage->pages;
1987            if (drain && pobjects > s->cpu_partial) {
1988                unsigned long flags;
1989                /*
1990                 * partial array is full. Move the existing
1991                 * set to the per node partial list.
1992                 */
1993                local_irq_save(flags);
1994                unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
1995                local_irq_restore(flags);
1996                oldpage = NULL;
1997                pobjects = 0;
1998                pages = 0;
1999                stat(s, CPU_PARTIAL_DRAIN);
2000            }
2001        }
2002
2003        pages++;
2004        pobjects += page->objects - page->inuse;
2005
2006        page->pages = pages;
2007        page->pobjects = pobjects;
2008        page->next = oldpage;
2009
2010    } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2011                                != oldpage);
2012#endif
2013}
2014
2015static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2016{
2017    stat(s, CPUSLAB_FLUSH);
2018    deactivate_slab(s, c->page, c->freelist);
2019
2020    c->tid = next_tid(c->tid);
2021    c->page = NULL;
2022    c->freelist = NULL;
2023}
2024
2025/*
2026 * Flush cpu slab.
2027 *
2028 * Called from IPI handler with interrupts disabled.
2029 */
2030static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2031{
2032    struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2033
2034    if (likely(c)) {
2035        if (c->page)
2036            flush_slab(s, c);
2037
2038        unfreeze_partials(s, c);
2039    }
2040}
2041
2042static void flush_cpu_slab(void *d)
2043{
2044    struct kmem_cache *s = d;
2045
2046    __flush_cpu_slab(s, smp_processor_id());
2047}
2048
2049static bool has_cpu_slab(int cpu, void *info)
2050{
2051    struct kmem_cache *s = info;
2052    struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2053
2054    return c->page || c->partial;
2055}
2056
2057static void flush_all(struct kmem_cache *s)
2058{
2059    on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2060}
2061
2062/*
2063 * Check if the objects in a per cpu structure fit numa
2064 * locality expectations.
2065 */
2066static inline int node_match(struct page *page, int node)
2067{
2068#ifdef CONFIG_NUMA
2069    if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2070        return 0;
2071#endif
2072    return 1;
2073}
2074
2075static int count_free(struct page *page)
2076{
2077    return page->objects - page->inuse;
2078}
2079
2080static unsigned long count_partial(struct kmem_cache_node *n,
2081                    int (*get_count)(struct page *))
2082{
2083    unsigned long flags;
2084    unsigned long x = 0;
2085    struct page *page;
2086
2087    spin_lock_irqsave(&n->list_lock, flags);
2088    list_for_each_entry(page, &n->partial, lru)
2089        x += get_count(page);
2090    spin_unlock_irqrestore(&n->list_lock, flags);
2091    return x;
2092}
2093
2094static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2095{
2096#ifdef CONFIG_SLUB_DEBUG
2097    return atomic_long_read(&n->total_objects);
2098#else
2099    return 0;
2100#endif
2101}
2102
2103static noinline void
2104slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2105{
2106    int node;
2107
2108    printk(KERN_WARNING
2109        "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2110        nid, gfpflags);
2111    printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, "
2112        "default order: %d, min order: %d\n", s->name, s->object_size,
2113        s->size, oo_order(s->oo), oo_order(s->min));
2114
2115    if (oo_order(s->min) > get_order(s->object_size))
2116        printk(KERN_WARNING " %s debugging increased min order, use "
2117               "slub_debug=O to disable.\n", s->name);
2118
2119    for_each_online_node(node) {
2120        struct kmem_cache_node *n = get_node(s, node);
2121        unsigned long nr_slabs;
2122        unsigned long nr_objs;
2123        unsigned long nr_free;
2124
2125        if (!n)
2126            continue;
2127
2128        nr_free = count_partial(n, count_free);
2129        nr_slabs = node_nr_slabs(n);
2130        nr_objs = node_nr_objs(n);
2131
2132        printk(KERN_WARNING
2133            " node %d: slabs: %ld, objs: %ld, free: %ld\n",
2134            node, nr_slabs, nr_objs, nr_free);
2135    }
2136}
2137
2138static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2139            int node, struct kmem_cache_cpu **pc)
2140{
2141    void *freelist;
2142    struct kmem_cache_cpu *c = *pc;
2143    struct page *page;
2144
2145    freelist = get_partial(s, flags, node, c);
2146
2147    if (freelist)
2148        return freelist;
2149
2150    page = new_slab(s, flags, node);
2151    if (page) {
2152        c = __this_cpu_ptr(s->cpu_slab);
2153        if (c->page)
2154            flush_slab(s, c);
2155
2156        /*
2157         * No other reference to the page yet so we can
2158         * muck around with it freely without cmpxchg
2159         */
2160        freelist = page->freelist;
2161        page->freelist = NULL;
2162
2163        stat(s, ALLOC_SLAB);
2164        c->page = page;
2165        *pc = c;
2166    } else
2167        freelist = NULL;
2168
2169    return freelist;
2170}
2171
2172static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2173{
2174    if (unlikely(PageSlabPfmemalloc(page)))
2175        return gfp_pfmemalloc_allowed(gfpflags);
2176
2177    return true;
2178}
2179
2180/*
2181 * Check the page->freelist of a page and either transfer the freelist to the
2182 * per cpu freelist or deactivate the page.
2183 *
2184 * The page is still frozen if the return value is not NULL.
2185 *
2186 * If this function returns NULL then the page has been unfrozen.
2187 *
2188 * This function must be called with interrupt disabled.
2189 */
2190static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2191{
2192    struct page new;
2193    unsigned long counters;
2194    void *freelist;
2195
2196    do {
2197        freelist = page->freelist;
2198        counters = page->counters;
2199
2200        new.counters = counters;
2201        VM_BUG_ON(!new.frozen);
2202
2203        new.inuse = page->objects;
2204        new.frozen = freelist != NULL;
2205
2206    } while (!__cmpxchg_double_slab(s, page,
2207        freelist, counters,
2208        NULL, new.counters,
2209        "get_freelist"));
2210
2211    return freelist;
2212}
2213
2214/*
2215 * Slow path. The lockless freelist is empty or we need to perform
2216 * debugging duties.
2217 *
2218 * Processing is still very fast if new objects have been freed to the
2219 * regular freelist. In that case we simply take over the regular freelist
2220 * as the lockless freelist and zap the regular freelist.
2221 *
2222 * If that is not working then we fall back to the partial lists. We take the
2223 * first element of the freelist as the object to allocate now and move the
2224 * rest of the freelist to the lockless freelist.
2225 *
2226 * And if we were unable to get a new slab from the partial slab lists then
2227 * we need to allocate a new slab. This is the slowest path since it involves
2228 * a call to the page allocator and the setup of a new slab.
2229 */
2230static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2231              unsigned long addr, struct kmem_cache_cpu *c)
2232{
2233    void *freelist;
2234    struct page *page;
2235    unsigned long flags;
2236
2237    local_irq_save(flags);
2238#ifdef CONFIG_PREEMPT
2239    /*
2240     * We may have been preempted and rescheduled on a different
2241     * cpu before disabling interrupts. Need to reload cpu area
2242     * pointer.
2243     */
2244    c = this_cpu_ptr(s->cpu_slab);
2245#endif
2246
2247    page = c->page;
2248    if (!page)
2249        goto new_slab;
2250redo:
2251
2252    if (unlikely(!node_match(page, node))) {
2253        stat(s, ALLOC_NODE_MISMATCH);
2254        deactivate_slab(s, page, c->freelist);
2255        c->page = NULL;
2256        c->freelist = NULL;
2257        goto new_slab;
2258    }
2259
2260    /*
2261     * By rights, we should be searching for a slab page that was
2262     * PFMEMALLOC but right now, we are losing the pfmemalloc
2263     * information when the page leaves the per-cpu allocator
2264     */
2265    if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2266        deactivate_slab(s, page, c->freelist);
2267        c->page = NULL;
2268        c->freelist = NULL;
2269        goto new_slab;
2270    }
2271
2272    /* must check again c->freelist in case of cpu migration or IRQ */
2273    freelist = c->freelist;
2274    if (freelist)
2275        goto load_freelist;
2276
2277    stat(s, ALLOC_SLOWPATH);
2278
2279    freelist = get_freelist(s, page);
2280
2281    if (!freelist) {
2282        c->page = NULL;
2283        stat(s, DEACTIVATE_BYPASS);
2284        goto new_slab;
2285    }
2286
2287    stat(s, ALLOC_REFILL);
2288
2289load_freelist:
2290    /*
2291     * freelist is pointing to the list of objects to be used.
2292     * page is pointing to the page from which the objects are obtained.
2293     * That page must be frozen for per cpu allocations to work.
2294     */
2295    VM_BUG_ON(!c->page->frozen);
2296    c->freelist = get_freepointer(s, freelist);
2297    c->tid = next_tid(c->tid);
2298    local_irq_restore(flags);
2299    return freelist;
2300
2301new_slab:
2302
2303    if (c->partial) {
2304        page = c->page = c->partial;
2305        c->partial = page->next;
2306        stat(s, CPU_PARTIAL_ALLOC);
2307        c->freelist = NULL;
2308        goto redo;
2309    }
2310
2311    freelist = new_slab_objects(s, gfpflags, node, &c);
2312
2313    if (unlikely(!freelist)) {
2314        if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
2315            slab_out_of_memory(s, gfpflags, node);
2316
2317        local_irq_restore(flags);
2318        return NULL;
2319    }
2320
2321    page = c->page;
2322    if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2323        goto load_freelist;
2324
2325    /* Only entered in the debug case */
2326    if (kmem_cache_debug(s) &&
2327            !alloc_debug_processing(s, page, freelist, addr))
2328        goto new_slab; /* Slab failed checks. Next slab needed */
2329
2330    deactivate_slab(s, page, get_freepointer(s, freelist));
2331    c->page = NULL;
2332    c->freelist = NULL;
2333    local_irq_restore(flags);
2334    return freelist;
2335}
2336
2337/*
2338 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2339 * have the fastpath folded into their functions. So no function call
2340 * overhead for requests that can be satisfied on the fastpath.
2341 *
2342 * The fastpath works by first checking if the lockless freelist can be used.
2343 * If not then __slab_alloc is called for slow processing.
2344 *
2345 * Otherwise we can simply pick the next object from the lockless free list.
2346 */
2347static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2348        gfp_t gfpflags, int node, unsigned long addr)
2349{
2350    void **object;
2351    struct kmem_cache_cpu *c;
2352    struct page *page;
2353    unsigned long tid;
2354
2355    if (slab_pre_alloc_hook(s, gfpflags))
2356        return NULL;
2357
2358    s = memcg_kmem_get_cache(s, gfpflags);
2359redo:
2360    /*
2361     * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2362     * enabled. We may switch back and forth between cpus while
2363     * reading from one cpu area. That does not matter as long
2364     * as we end up on the original cpu again when doing the cmpxchg.
2365     *
2366     * Preemption is disabled for the retrieval of the tid because that
2367     * must occur from the current processor. We cannot allow rescheduling
2368     * on a different processor between the determination of the pointer
2369     * and the retrieval of the tid.
2370     */
2371    preempt_disable();
2372    c = __this_cpu_ptr(s->cpu_slab);
2373
2374    /*
2375     * The transaction ids are globally unique per cpu and per operation on
2376     * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2377     * occurs on the right processor and that there was no operation on the
2378     * linked list in between.
2379     */
2380    tid = c->tid;
2381    preempt_enable();
2382
2383    object = c->freelist;
2384    page = c->page;
2385    if (unlikely(!object || !node_match(page, node)))
2386        object = __slab_alloc(s, gfpflags, node, addr, c);
2387
2388    else {
2389        void *next_object = get_freepointer_safe(s, object);
2390
2391        /*
2392         * The cmpxchg will only match if there was no additional
2393         * operation and if we are on the right processor.
2394         *
2395         * The cmpxchg does the following atomically (without lock
2396         * semantics!)
2397         * 1. Relocate first pointer to the current per cpu area.
2398         * 2. Verify that tid and freelist have not been changed
2399         * 3. If they were not changed replace tid and freelist
2400         *
2401         * Since this is without lock semantics the protection is only
2402         * against code executing on this cpu *not* from access by
2403         * other cpus.
2404         */
2405        if (unlikely(!this_cpu_cmpxchg_double(
2406                s->cpu_slab->freelist, s->cpu_slab->tid,
2407                object, tid,
2408                next_object, next_tid(tid)))) {
2409
2410            note_cmpxchg_failure("slab_alloc", s, tid);
2411            goto redo;
2412        }
2413        prefetch_freepointer(s, next_object);
2414        stat(s, ALLOC_FASTPATH);
2415    }
2416
2417    if (unlikely(gfpflags & __GFP_ZERO) && object)
2418        memset(object, 0, s->object_size);
2419
2420    slab_post_alloc_hook(s, gfpflags, object);
2421
2422    return object;
2423}
2424
2425static __always_inline void *slab_alloc(struct kmem_cache *s,
2426        gfp_t gfpflags, unsigned long addr)
2427{
2428    return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2429}
2430
2431void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2432{
2433    void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2434
2435    trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2436                s->size, gfpflags);
2437
2438    return ret;
2439}
2440EXPORT_SYMBOL(kmem_cache_alloc);
2441
2442#ifdef CONFIG_TRACING
2443void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2444{
2445    void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2446    trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2447    return ret;
2448}
2449EXPORT_SYMBOL(kmem_cache_alloc_trace);
2450#endif
2451
2452#ifdef CONFIG_NUMA
2453void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2454{
2455    void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2456
2457    trace_kmem_cache_alloc_node(_RET_IP_, ret,
2458                    s->object_size, s->size, gfpflags, node);
2459
2460    return ret;
2461}
2462EXPORT_SYMBOL(kmem_cache_alloc_node);
2463
2464#ifdef CONFIG_TRACING
2465void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2466                    gfp_t gfpflags,
2467                    int node, size_t size)
2468{
2469    void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2470
2471    trace_kmalloc_node(_RET_IP_, ret,
2472               size, s->size, gfpflags, node);
2473    return ret;
2474}
2475EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2476#endif
2477#endif
2478
2479/*
2480 * Slow patch handling. This may still be called frequently since objects
2481 * have a longer lifetime than the cpu slabs in most processing loads.
2482 *
2483 * So we still attempt to reduce cache line usage. Just take the slab
2484 * lock and free the item. If there is no additional partial page
2485 * handling required then we can return immediately.
2486 */
2487static void __slab_free(struct kmem_cache *s, struct page *page,
2488            void *x, unsigned long addr)
2489{
2490    void *prior;
2491    void **object = (void *)x;
2492    int was_frozen;
2493    struct page new;
2494    unsigned long counters;
2495    struct kmem_cache_node *n = NULL;
2496    unsigned long uninitialized_var(flags);
2497
2498    stat(s, FREE_SLOWPATH);
2499
2500    if (kmem_cache_debug(s) &&
2501        !(n = free_debug_processing(s, page, x, addr, &flags)))
2502        return;
2503
2504    do {
2505        if (unlikely(n)) {
2506            spin_unlock_irqrestore(&n->list_lock, flags);
2507            n = NULL;
2508        }
2509        prior = page->freelist;
2510        counters = page->counters;
2511        set_freepointer(s, object, prior);
2512        new.counters = counters;
2513        was_frozen = new.frozen;
2514        new.inuse--;
2515        if ((!new.inuse || !prior) && !was_frozen) {
2516
2517            if (kmem_cache_has_cpu_partial(s) && !prior)
2518
2519                /*
2520                 * Slab was on no list before and will be
2521                 * partially empty
2522                 * We can defer the list move and instead
2523                 * freeze it.
2524                 */
2525                new.frozen = 1;
2526
2527            else { /* Needs to be taken off a list */
2528
2529                            n = get_node(s, page_to_nid(page));
2530                /*
2531                 * Speculatively acquire the list_lock.
2532                 * If the cmpxchg does not succeed then we may
2533                 * drop the list_lock without any processing.
2534                 *
2535                 * Otherwise the list_lock will synchronize with
2536                 * other processors updating the list of slabs.
2537                 */
2538                spin_lock_irqsave(&n->list_lock, flags);
2539
2540            }
2541        }
2542
2543    } while (!cmpxchg_double_slab(s, page,
2544        prior, counters,
2545        object, new.counters,
2546        "__slab_free"));
2547
2548    if (likely(!n)) {
2549
2550        /*
2551         * If we just froze the page then put it onto the
2552         * per cpu partial list.
2553         */
2554        if (new.frozen && !was_frozen) {
2555            put_cpu_partial(s, page, 1);
2556            stat(s, CPU_PARTIAL_FREE);
2557        }
2558        /*
2559         * The list lock was not taken therefore no list
2560         * activity can be necessary.
2561         */
2562                if (was_frozen)
2563                        stat(s, FREE_FROZEN);
2564                return;
2565        }
2566
2567    if (unlikely(!new.inuse && n->nr_partial > s->min_partial))
2568        goto slab_empty;
2569
2570    /*
2571     * Objects left in the slab. If it was not on the partial list before
2572     * then add it.
2573     */
2574    if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2575        if (kmem_cache_debug(s))
2576            remove_full(s, page);
2577        add_partial(n, page, DEACTIVATE_TO_TAIL);
2578        stat(s, FREE_ADD_PARTIAL);
2579    }
2580    spin_unlock_irqrestore(&n->list_lock, flags);
2581    return;
2582
2583slab_empty:
2584    if (prior) {
2585        /*
2586         * Slab on the partial list.
2587         */
2588        remove_partial(n, page);
2589        stat(s, FREE_REMOVE_PARTIAL);
2590    } else
2591        /* Slab must be on the full list */
2592        remove_full(s, page);
2593
2594    spin_unlock_irqrestore(&n->list_lock, flags);
2595    stat(s, FREE_SLAB);
2596    discard_slab(s, page);
2597}
2598
2599/*
2600 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2601 * can perform fastpath freeing without additional function calls.
2602 *
2603 * The fastpath is only possible if we are freeing to the current cpu slab
2604 * of this processor. This typically the case if we have just allocated
2605 * the item before.
2606 *
2607 * If fastpath is not possible then fall back to __slab_free where we deal
2608 * with all sorts of special processing.
2609 */
2610static __always_inline void slab_free(struct kmem_cache *s,
2611            struct page *page, void *x, unsigned long addr)
2612{
2613    void **object = (void *)x;
2614    struct kmem_cache_cpu *c;
2615    unsigned long tid;
2616
2617    slab_free_hook(s, x);
2618
2619redo:
2620    /*
2621     * Determine the currently cpus per cpu slab.
2622     * The cpu may change afterward. However that does not matter since
2623     * data is retrieved via this pointer. If we are on the same cpu
2624     * during the cmpxchg then the free will succedd.
2625     */
2626    preempt_disable();
2627    c = __this_cpu_ptr(s->cpu_slab);
2628
2629    tid = c->tid;
2630    preempt_enable();
2631
2632    if (likely(page == c->page)) {
2633        set_freepointer(s, object, c->freelist);
2634
2635        if (unlikely(!this_cpu_cmpxchg_double(
2636                s->cpu_slab->freelist, s->cpu_slab->tid,
2637                c->freelist, tid,
2638                object, next_tid(tid)))) {
2639
2640            note_cmpxchg_failure("slab_free", s, tid);
2641            goto redo;
2642        }
2643        stat(s, FREE_FASTPATH);
2644    } else
2645        __slab_free(s, page, x, addr);
2646
2647}
2648
2649void kmem_cache_free(struct kmem_cache *s, void *x)
2650{
2651    s = cache_from_obj(s, x);
2652    if (!s)
2653        return;
2654    slab_free(s, virt_to_head_page(x), x, _RET_IP_);
2655    trace_kmem_cache_free(_RET_IP_, x);
2656}
2657EXPORT_SYMBOL(kmem_cache_free);
2658
2659/*
2660 * Object placement in a slab is made very easy because we always start at
2661 * offset 0. If we tune the size of the object to the alignment then we can
2662 * get the required alignment by putting one properly sized object after
2663 * another.
2664 *
2665 * Notice that the allocation order determines the sizes of the per cpu
2666 * caches. Each processor has always one slab available for allocations.
2667 * Increasing the allocation order reduces the number of times that slabs
2668 * must be moved on and off the partial lists and is therefore a factor in
2669 * locking overhead.
2670 */
2671
2672/*
2673 * Mininum / Maximum order of slab pages. This influences locking overhead
2674 * and slab fragmentation. A higher order reduces the number of partial slabs
2675 * and increases the number of allocations possible without having to
2676 * take the list_lock.
2677 */
2678static int slub_min_order;
2679static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
2680static int slub_min_objects;
2681
2682/*
2683 * Merge control. If this is set then no merging of slab caches will occur.
2684 * (Could be removed. This was introduced to pacify the merge skeptics.)
2685 */
2686static int slub_nomerge;
2687
2688/*
2689 * Calculate the order of allocation given an slab object size.
2690 *
2691 * The order of allocation has significant impact on performance and other
2692 * system components. Generally order 0 allocations should be preferred since
2693 * order 0 does not cause fragmentation in the page allocator. Larger objects
2694 * be problematic to put into order 0 slabs because there may be too much
2695 * unused space left. We go to a higher order if more than 1/16th of the slab
2696 * would be wasted.
2697 *
2698 * In order to reach satisfactory performance we must ensure that a minimum
2699 * number of objects is in one slab. Otherwise we may generate too much
2700 * activity on the partial lists which requires taking the list_lock. This is
2701 * less a concern for large slabs though which are rarely used.
2702 *
2703 * slub_max_order specifies the order where we begin to stop considering the
2704 * number of objects in a slab as critical. If we reach slub_max_order then
2705 * we try to keep the page order as low as possible. So we accept more waste
2706 * of space in favor of a small page order.
2707 *
2708 * Higher order allocations also allow the placement of more objects in a
2709 * slab and thereby reduce object handling overhead. If the user has
2710 * requested a higher mininum order then we start with that one instead of
2711 * the smallest order which will fit the object.
2712 */
2713static inline int slab_order(int size, int min_objects,
2714                int max_order, int fract_leftover, int reserved)
2715{
2716    int order;
2717    int rem;
2718    int min_order = slub_min_order;
2719
2720    if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
2721        return get_order(size * MAX_OBJS_PER_PAGE) - 1;
2722
2723    for (order = max(min_order,
2724                fls(min_objects * size - 1) - PAGE_SHIFT);
2725            order <= max_order; order++) {
2726
2727        unsigned long slab_size = PAGE_SIZE << order;
2728
2729        if (slab_size < min_objects * size + reserved)
2730            continue;
2731
2732        rem = (slab_size - reserved) % size;
2733
2734        if (rem <= slab_size / fract_leftover)
2735            break;
2736
2737    }
2738
2739    return order;
2740}
2741
2742static inline int calculate_order(int size, int reserved)
2743{
2744    int order;
2745    int min_objects;
2746    int fraction;
2747    int max_objects;
2748
2749    /*
2750     * Attempt to find best configuration for a slab. This
2751     * works by first attempting to generate a layout with
2752     * the best configuration and backing off gradually.
2753     *
2754     * First we reduce the acceptable waste in a slab. Then
2755     * we reduce the minimum objects required in a slab.
2756     */
2757    min_objects = slub_min_objects;
2758    if (!min_objects)
2759        min_objects = 4 * (fls(nr_cpu_ids) + 1);
2760    max_objects = order_objects(slub_max_order, size, reserved);
2761    min_objects = min(min_objects, max_objects);
2762
2763    while (min_objects > 1) {
2764        fraction = 16;
2765        while (fraction >= 4) {
2766            order = slab_order(size, min_objects,
2767                    slub_max_order, fraction, reserved);
2768            if (order <= slub_max_order)
2769                return order;
2770            fraction /= 2;
2771        }
2772        min_objects--;
2773    }
2774
2775    /*
2776     * We were unable to place multiple objects in a slab. Now
2777     * lets see if we can place a single object there.
2778     */
2779    order = slab_order(size, 1, slub_max_order, 1, reserved);
2780    if (order <= slub_max_order)
2781        return order;
2782
2783    /*
2784     * Doh this slab cannot be placed using slub_max_order.
2785     */
2786    order = slab_order(size, 1, MAX_ORDER, 1, reserved);
2787    if (order < MAX_ORDER)
2788        return order;
2789    return -ENOSYS;
2790}
2791
2792static void
2793init_kmem_cache_node(struct kmem_cache_node *n)
2794{
2795    n->nr_partial = 0;
2796    spin_lock_init(&n->list_lock);
2797    INIT_LIST_HEAD(&n->partial);
2798#ifdef CONFIG_SLUB_DEBUG
2799    atomic_long_set(&n->nr_slabs, 0);
2800    atomic_long_set(&n->total_objects, 0);
2801    INIT_LIST_HEAD(&n->full);
2802#endif
2803}
2804
2805static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
2806{
2807    BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
2808            KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
2809
2810    /*
2811     * Must align to double word boundary for the double cmpxchg
2812     * instructions to work; see __pcpu_double_call_return_bool().
2813     */
2814    s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2815                     2 * sizeof(void *));
2816
2817    if (!s->cpu_slab)
2818        return 0;
2819
2820    init_kmem_cache_cpus(s);
2821
2822    return 1;
2823}
2824
2825static struct kmem_cache *kmem_cache_node;
2826
2827/*
2828 * No kmalloc_node yet so do it by hand. We know that this is the first
2829 * slab on the node for this slabcache. There are no concurrent accesses
2830 * possible.
2831 *
2832 * Note that this function only works on the kmalloc_node_cache
2833 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2834 * memory on a fresh node that has no slab structures yet.
2835 */
2836static void early_kmem_cache_node_alloc(int node)
2837{
2838    struct page *page;
2839    struct kmem_cache_node *n;
2840
2841    BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
2842
2843    page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
2844
2845    BUG_ON(!page);
2846    if (page_to_nid(page) != node) {
2847        printk(KERN_ERR "SLUB: Unable to allocate memory from "
2848                "node %d\n", node);
2849        printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2850                "in order to be able to continue\n");
2851    }
2852
2853    n = page->freelist;
2854    BUG_ON(!n);
2855    page->freelist = get_freepointer(kmem_cache_node, n);
2856    page->inuse = 1;
2857    page->frozen = 0;
2858    kmem_cache_node->node[node] = n;
2859#ifdef CONFIG_SLUB_DEBUG
2860    init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
2861    init_tracking(kmem_cache_node, n);
2862#endif
2863    init_kmem_cache_node(n);
2864    inc_slabs_node(kmem_cache_node, node, page->objects);
2865
2866    add_partial(n, page, DEACTIVATE_TO_HEAD);
2867}
2868
2869static void free_kmem_cache_nodes(struct kmem_cache *s)
2870{
2871    int node;
2872
2873    for_each_node_state(node, N_NORMAL_MEMORY) {
2874        struct kmem_cache_node *n = s->node[node];
2875
2876        if (n)
2877            kmem_cache_free(kmem_cache_node, n);
2878
2879        s->node[node] = NULL;
2880    }
2881}
2882
2883static int init_kmem_cache_nodes(struct kmem_cache *s)
2884{
2885    int node;
2886
2887    for_each_node_state(node, N_NORMAL_MEMORY) {
2888        struct kmem_cache_node *n;
2889
2890        if (slab_state == DOWN) {
2891            early_kmem_cache_node_alloc(node);
2892            continue;
2893        }
2894        n = kmem_cache_alloc_node(kmem_cache_node,
2895                        GFP_KERNEL, node);
2896
2897        if (!n) {
2898            free_kmem_cache_nodes(s);
2899            return 0;
2900        }
2901
2902        s->node[node] = n;
2903        init_kmem_cache_node(n);
2904    }
2905    return 1;
2906}
2907
2908static void set_min_partial(struct kmem_cache *s, unsigned long min)
2909{
2910    if (min < MIN_PARTIAL)
2911        min = MIN_PARTIAL;
2912    else if (min > MAX_PARTIAL)
2913        min = MAX_PARTIAL;
2914    s->min_partial = min;
2915}
2916
2917/*
2918 * calculate_sizes() determines the order and the distribution of data within
2919 * a slab object.
2920 */
2921static int calculate_sizes(struct kmem_cache *s, int forced_order)
2922{
2923    unsigned long flags = s->flags;
2924    unsigned long size = s->object_size;
2925    int order;
2926
2927    /*
2928     * Round up object size to the next word boundary. We can only
2929     * place the free pointer at word boundaries and this determines
2930     * the possible location of the free pointer.
2931     */
2932    size = ALIGN(size, sizeof(void *));
2933
2934#ifdef CONFIG_SLUB_DEBUG
2935    /*
2936     * Determine if we can poison the object itself. If the user of
2937     * the slab may touch the object after free or before allocation
2938     * then we should never poison the object itself.
2939     */
2940    if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2941            !s->ctor)
2942        s->flags |= __OBJECT_POISON;
2943    else
2944        s->flags &= ~__OBJECT_POISON;
2945
2946
2947    /*
2948     * If we are Redzoning then check if there is some space between the
2949     * end of the object and the free pointer. If not then add an
2950     * additional word to have some bytes to store Redzone information.
2951     */
2952    if ((flags & SLAB_RED_ZONE) && size == s->object_size)
2953        size += sizeof(void *);
2954#endif
2955
2956    /*
2957     * With that we have determined the number of bytes in actual use
2958     * by the object. This is the potential offset to the free pointer.
2959     */
2960    s->inuse = size;
2961
2962    if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2963        s->ctor)) {
2964        /*
2965         * Relocate free pointer after the object if it is not
2966         * permitted to overwrite the first word of the object on
2967         * kmem_cache_free.
2968         *
2969         * This is the case if we do RCU, have a constructor or
2970         * destructor or are poisoning the objects.
2971         */
2972        s->offset = size;
2973        size += sizeof(void *);
2974    }
2975
2976#ifdef CONFIG_SLUB_DEBUG
2977    if (flags & SLAB_STORE_USER)
2978        /*
2979         * Need to store information about allocs and frees after
2980         * the object.
2981         */
2982        size += 2 * sizeof(struct track);
2983
2984    if (flags & SLAB_RED_ZONE)
2985        /*
2986         * Add some empty padding so that we can catch
2987         * overwrites from earlier objects rather than let
2988         * tracking information or the free pointer be
2989         * corrupted if a user writes before the start
2990         * of the object.
2991         */
2992        size += sizeof(void *);
2993#endif
2994
2995    /*
2996     * SLUB stores one object immediately after another beginning from
2997     * offset 0. In order to align the objects we have to simply size
2998     * each object to conform to the alignment.
2999     */
3000    size = ALIGN(size, s->align);
3001    s->size = size;
3002    if (forced_order >= 0)
3003        order = forced_order;
3004    else
3005        order = calculate_order(size, s->reserved);
3006
3007    if (order < 0)
3008        return 0;
3009
3010    s->allocflags = 0;
3011    if (order)
3012        s->allocflags |= __GFP_COMP;
3013
3014    if (s->flags & SLAB_CACHE_DMA)
3015        s->allocflags |= GFP_DMA;
3016
3017    if (s->flags & SLAB_RECLAIM_ACCOUNT)
3018        s->allocflags |= __GFP_RECLAIMABLE;
3019
3020    /*
3021     * Determine the number of objects per slab
3022     */
3023    s->oo = oo_make(order, size, s->reserved);
3024    s->min = oo_make(get_order(size), size, s->reserved);
3025    if (oo_objects(s->oo) > oo_objects(s->max))
3026        s->max = s->oo;
3027
3028    return !!oo_objects(s->oo);
3029}
3030
3031static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
3032{
3033    s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3034    s->reserved = 0;
3035
3036    if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3037        s->reserved = sizeof(struct rcu_head);
3038
3039    if (!calculate_sizes(s, -1))
3040        goto error;
3041    if (disable_higher_order_debug) {
3042        /*
3043         * Disable debugging flags that store metadata if the min slab
3044         * order increased.
3045         */
3046        if (get_order(s->size) > get_order(s->object_size)) {
3047            s->flags &= ~DEBUG_METADATA_FLAGS;
3048            s->offset = 0;
3049            if (!calculate_sizes(s, -1))
3050                goto error;
3051        }
3052    }
3053
3054#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3055    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3056    if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
3057        /* Enable fast mode */
3058        s->flags |= __CMPXCHG_DOUBLE;
3059#endif
3060
3061    /*
3062     * The larger the object size is, the more pages we want on the partial
3063     * list to avoid pounding the page allocator excessively.
3064     */
3065    set_min_partial(s, ilog2(s->size) / 2);
3066
3067    /*
3068     * cpu_partial determined the maximum number of objects kept in the
3069     * per cpu partial lists of a processor.
3070     *
3071     * Per cpu partial lists mainly contain slabs that just have one
3072     * object freed. If they are used for allocation then they can be
3073     * filled up again with minimal effort. The slab will never hit the
3074     * per node partial lists and therefore no locking will be required.
3075     *
3076     * This setting also determines
3077     *
3078     * A) The number of objects from per cpu partial slabs dumped to the
3079     * per node list when we reach the limit.
3080     * B) The number of objects in cpu partial slabs to extract from the
3081     * per node list when we run out of per cpu objects. We only fetch
3082     * 50% to keep some capacity around for frees.
3083     */
3084    if (!kmem_cache_has_cpu_partial(s))
3085        s->cpu_partial = 0;
3086    else if (s->size >= PAGE_SIZE)
3087        s->cpu_partial = 2;
3088    else if (s->size >= 1024)
3089        s->cpu_partial = 6;
3090    else if (s->size >= 256)
3091        s->cpu_partial = 13;
3092    else
3093        s->cpu_partial = 30;
3094
3095#ifdef CONFIG_NUMA
3096    s->remote_node_defrag_ratio = 1000;
3097#endif
3098    if (!init_kmem_cache_nodes(s))
3099        goto error;
3100
3101    if (alloc_kmem_cache_cpus(s))
3102        return 0;
3103
3104    free_kmem_cache_nodes(s);
3105error:
3106    if (flags & SLAB_PANIC)
3107        panic("Cannot create slab %s size=%lu realsize=%u "
3108            "order=%u offset=%u flags=%lx\n",
3109            s->name, (unsigned long)s->size, s->size,
3110            oo_order(s->oo), s->offset, flags);
3111    return -EINVAL;
3112}
3113
3114static void list_slab_objects(struct kmem_cache *s, struct page *page,
3115                            const char *text)
3116{
3117#ifdef CONFIG_SLUB_DEBUG
3118    void *addr = page_address(page);
3119    void *p;
3120    unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3121                     sizeof(long), GFP_ATOMIC);
3122    if (!map)
3123        return;
3124    slab_err(s, page, text, s->name);
3125    slab_lock(page);
3126
3127    get_map(s, page, map);
3128    for_each_object(p, s, addr, page->objects) {
3129
3130        if (!test_bit(slab_index(p, s, addr), map)) {
3131            printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
3132                            p, p - addr);
3133            print_tracking(s, p);
3134        }
3135    }
3136    slab_unlock(page);
3137    kfree(map);
3138#endif
3139}
3140
3141/*
3142 * Attempt to free all partial slabs on a node.
3143 * This is called from kmem_cache_close(). We must be the last thread
3144 * using the cache and therefore we do not need to lock anymore.
3145 */
3146static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3147{
3148    struct page *page, *h;
3149
3150    list_for_each_entry_safe(page, h, &n->partial, lru) {
3151        if (!page->inuse) {
3152            remove_partial(n, page);
3153            discard_slab(s, page);
3154        } else {
3155            list_slab_objects(s, page,
3156            "Objects remaining in %s on kmem_cache_close()");
3157        }
3158    }
3159}
3160
3161/*
3162 * Release all resources used by a slab cache.
3163 */
3164static inline int kmem_cache_close(struct kmem_cache *s)
3165{
3166    int node;
3167
3168    flush_all(s);
3169    /* Attempt to free all objects */
3170    for_each_node_state(node, N_NORMAL_MEMORY) {
3171        struct kmem_cache_node *n = get_node(s, node);
3172
3173        free_partial(s, n);
3174        if (n->nr_partial || slabs_node(s, node))
3175            return 1;
3176    }
3177    free_percpu(s->cpu_slab);
3178    free_kmem_cache_nodes(s);
3179    return 0;
3180}
3181
3182int __kmem_cache_shutdown(struct kmem_cache *s)
3183{
3184    int rc = kmem_cache_close(s);
3185
3186    if (!rc) {
3187        /*
3188         * We do the same lock strategy around sysfs_slab_add, see
3189         * __kmem_cache_create. Because this is pretty much the last
3190         * operation we do and the lock will be released shortly after
3191         * that in slab_common.c, we could just move sysfs_slab_remove
3192         * to a later point in common code. We should do that when we
3193         * have a common sysfs framework for all allocators.
3194         */
3195        mutex_unlock(&slab_mutex);
3196        sysfs_slab_remove(s);
3197        mutex_lock(&slab_mutex);
3198    }
3199
3200    return rc;
3201}
3202
3203/********************************************************************
3204 * Kmalloc subsystem
3205 *******************************************************************/
3206
3207static int __init setup_slub_min_order(char *str)
3208{
3209    get_option(&str, &slub_min_order);
3210
3211    return 1;
3212}
3213
3214__setup("slub_min_order=", setup_slub_min_order);
3215
3216static int __init setup_slub_max_order(char *str)
3217{
3218    get_option(&str, &slub_max_order);
3219    slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3220
3221    return 1;
3222}
3223
3224__setup("slub_max_order=", setup_slub_max_order);
3225
3226static int __init setup_slub_min_objects(char *str)
3227{
3228    get_option(&str, &slub_min_objects);
3229
3230    return 1;
3231}
3232
3233__setup("slub_min_objects=", setup_slub_min_objects);
3234
3235static int __init setup_slub_nomerge(char *str)
3236{
3237    slub_nomerge = 1;
3238    return 1;
3239}
3240
3241__setup("slub_nomerge", setup_slub_nomerge);
3242
3243void *__kmalloc(size_t size, gfp_t flags)
3244{
3245    struct kmem_cache *s;
3246    void *ret;
3247
3248    if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3249        return kmalloc_large(size, flags);
3250
3251    s = kmalloc_slab(size, flags);
3252
3253    if (unlikely(ZERO_OR_NULL_PTR(s)))
3254        return s;
3255
3256    ret = slab_alloc(s, flags, _RET_IP_);
3257
3258    trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3259
3260    return ret;
3261}
3262EXPORT_SYMBOL(__kmalloc);
3263
3264#ifdef CONFIG_NUMA
3265static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3266{
3267    struct page *page;
3268    void *ptr = NULL;
3269
3270    flags |= __GFP_COMP | __GFP_NOTRACK | __GFP_KMEMCG;
3271    page = alloc_pages_node(node, flags, get_order(size));
3272    if (page)
3273        ptr = page_address(page);
3274
3275    kmemleak_alloc(ptr, size, 1, flags);
3276    return ptr;
3277}
3278
3279void *__kmalloc_node(size_t size, gfp_t flags, int node)
3280{
3281    struct kmem_cache *s;
3282    void *ret;
3283
3284    if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3285        ret = kmalloc_large_node(size, flags, node);
3286
3287        trace_kmalloc_node(_RET_IP_, ret,
3288                   size, PAGE_SIZE << get_order(size),
3289                   flags, node);
3290
3291        return ret;
3292    }
3293
3294    s = kmalloc_slab(size, flags);
3295
3296    if (unlikely(ZERO_OR_NULL_PTR(s)))
3297        return s;
3298
3299    ret = slab_alloc_node(s, flags, node, _RET_IP_);
3300
3301    trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3302
3303    return ret;
3304}
3305EXPORT_SYMBOL(__kmalloc_node);
3306#endif
3307
3308size_t ksize(const void *object)
3309{
3310    struct page *page;
3311
3312    if (unlikely(object == ZERO_SIZE_PTR))
3313        return 0;
3314
3315    page = virt_to_head_page(object);
3316
3317    if (unlikely(!PageSlab(page))) {
3318        WARN_ON(!PageCompound(page));
3319        return PAGE_SIZE << compound_order(page);
3320    }
3321
3322    return slab_ksize(page->slab_cache);
3323}
3324EXPORT_SYMBOL(ksize);
3325
3326void kfree(const void *x)
3327{
3328    struct page *page;
3329    void *object = (void *)x;
3330
3331    trace_kfree(_RET_IP_, x);
3332
3333    if (unlikely(ZERO_OR_NULL_PTR(x)))
3334        return;
3335
3336    page = virt_to_head_page(x);
3337    if (unlikely(!PageSlab(page))) {
3338        BUG_ON(!PageCompound(page));
3339        kmemleak_free(x);
3340        __free_memcg_kmem_pages(page, compound_order(page));
3341        return;
3342    }
3343    slab_free(page->slab_cache, page, object, _RET_IP_);
3344}
3345EXPORT_SYMBOL(kfree);
3346
3347/*
3348 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3349 * the remaining slabs by the number of items in use. The slabs with the
3350 * most items in use come first. New allocations will then fill those up
3351 * and thus they can be removed from the partial lists.
3352 *
3353 * The slabs with the least items are placed last. This results in them
3354 * being allocated from last increasing the chance that the last objects
3355 * are freed in them.
3356 */
3357int kmem_cache_shrink(struct kmem_cache *s)
3358{
3359    int node;
3360    int i;
3361    struct kmem_cache_node *n;
3362    struct page *page;
3363    struct page *t;
3364    int objects = oo_objects(s->max);
3365    struct list_head *slabs_by_inuse =
3366        kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
3367    unsigned long flags;
3368
3369    if (!slabs_by_inuse)
3370        return -ENOMEM;
3371
3372    flush_all(s);
3373    for_each_node_state(node, N_NORMAL_MEMORY) {
3374        n = get_node(s, node);
3375
3376        if (!n->nr_partial)
3377            continue;
3378
3379        for (i = 0; i < objects; i++)
3380            INIT_LIST_HEAD(slabs_by_inuse + i);
3381
3382        spin_lock_irqsave(&n->list_lock, flags);
3383
3384        /*
3385         * Build lists indexed by the items in use in each slab.
3386         *
3387         * Note that concurrent frees may occur while we hold the
3388         * list_lock. page->inuse here is the upper limit.
3389         */
3390        list_for_each_entry_safe(page, t, &n->partial, lru) {
3391            list_move(&page->lru, slabs_by_inuse + page->inuse);
3392            if (!page->inuse)
3393                n->nr_partial--;
3394        }
3395
3396        /*
3397         * Rebuild the partial list with the slabs filled up most
3398         * first and the least used slabs at the end.
3399         */
3400        for (i = objects - 1; i > 0; i--)
3401            list_splice(slabs_by_inuse + i, n->partial.prev);
3402
3403        spin_unlock_irqrestore(&n->list_lock, flags);
3404
3405        /* Release empty slabs */
3406        list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
3407            discard_slab(s, page);
3408    }
3409
3410    kfree(slabs_by_inuse);
3411    return 0;
3412}
3413EXPORT_SYMBOL(kmem_cache_shrink);
3414
3415static int slab_mem_going_offline_callback(void *arg)
3416{
3417    struct kmem_cache *s;
3418
3419    mutex_lock(&slab_mutex);
3420    list_for_each_entry(s, &slab_caches, list)
3421        kmem_cache_shrink(s);
3422    mutex_unlock(&slab_mutex);
3423
3424    return 0;
3425}
3426
3427static void slab_mem_offline_callback(void *arg)
3428{
3429    struct kmem_cache_node *n;
3430    struct kmem_cache *s;
3431    struct memory_notify *marg = arg;
3432    int offline_node;
3433
3434    offline_node = marg->status_change_nid_normal;
3435
3436    /*
3437     * If the node still has available memory. we need kmem_cache_node
3438     * for it yet.
3439     */
3440    if (offline_node < 0)
3441        return;
3442
3443    mutex_lock(&slab_mutex);
3444    list_for_each_entry(s, &slab_caches, list) {
3445        n = get_node(s, offline_node);
3446        if (n) {
3447            /*
3448             * if n->nr_slabs > 0, slabs still exist on the node
3449             * that is going down. We were unable to free them,
3450             * and offline_pages() function shouldn't call this
3451             * callback. So, we must fail.
3452             */
3453            BUG_ON(slabs_node(s, offline_node));
3454
3455            s->node[offline_node] = NULL;
3456            kmem_cache_free(kmem_cache_node, n);
3457        }
3458    }
3459    mutex_unlock(&slab_mutex);
3460}
3461
3462static int slab_mem_going_online_callback(void *arg)
3463{
3464    struct kmem_cache_node *n;
3465    struct kmem_cache *s;
3466    struct memory_notify *marg = arg;
3467    int nid = marg->status_change_nid_normal;
3468    int ret = 0;
3469
3470    /*
3471     * If the node's memory is already available, then kmem_cache_node is
3472     * already created. Nothing to do.
3473     */
3474    if (nid < 0)
3475        return 0;
3476
3477    /*
3478     * We are bringing a node online. No memory is available yet. We must
3479     * allocate a kmem_cache_node structure in order to bring the node
3480     * online.
3481     */
3482    mutex_lock(&slab_mutex);
3483    list_for_each_entry(s, &slab_caches, list) {
3484        /*
3485         * XXX: kmem_cache_alloc_node will fallback to other nodes
3486         * since memory is not yet available from the node that
3487         * is brought up.
3488         */
3489        n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3490        if (!n) {
3491            ret = -ENOMEM;
3492            goto out;
3493        }
3494        init_kmem_cache_node(n);
3495        s->node[nid] = n;
3496    }
3497out:
3498    mutex_unlock(&slab_mutex);
3499    return ret;
3500}
3501
3502static int slab_memory_callback(struct notifier_block *self,
3503                unsigned long action, void *arg)
3504{
3505    int ret = 0;
3506
3507    switch (action) {
3508    case MEM_GOING_ONLINE:
3509        ret = slab_mem_going_online_callback(arg);
3510        break;
3511    case MEM_GOING_OFFLINE:
3512        ret = slab_mem_going_offline_callback(arg);
3513        break;
3514    case MEM_OFFLINE:
3515    case MEM_CANCEL_ONLINE:
3516        slab_mem_offline_callback(arg);
3517        break;
3518    case MEM_ONLINE:
3519    case MEM_CANCEL_OFFLINE:
3520        break;
3521    }
3522    if (ret)
3523        ret = notifier_from_errno(ret);
3524    else
3525        ret = NOTIFY_OK;
3526    return ret;
3527}
3528
3529static struct notifier_block slab_memory_callback_nb = {
3530    .notifier_call = slab_memory_callback,
3531    .priority = SLAB_CALLBACK_PRI,
3532};
3533
3534/********************************************************************
3535 * Basic setup of slabs
3536 *******************************************************************/
3537
3538/*
3539 * Used for early kmem_cache structures that were allocated using
3540 * the page allocator. Allocate them properly then fix up the pointers
3541 * that may be pointing to the wrong kmem_cache structure.
3542 */
3543
3544static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
3545{
3546    int node;
3547    struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
3548
3549    memcpy(s, static_cache, kmem_cache->object_size);
3550
3551    /*
3552     * This runs very early, and only the boot processor is supposed to be
3553     * up. Even if it weren't true, IRQs are not up so we couldn't fire
3554     * IPIs around.
3555     */
3556    __flush_cpu_slab(s, smp_processor_id());
3557    for_each_node_state(node, N_NORMAL_MEMORY) {
3558        struct kmem_cache_node *n = get_node(s, node);
3559        struct page *p;
3560
3561        if (n) {
3562            list_for_each_entry(p, &n->partial, lru)
3563                p->slab_cache = s;
3564
3565#ifdef CONFIG_SLUB_DEBUG
3566            list_for_each_entry(p, &n->full, lru)
3567                p->slab_cache = s;
3568#endif
3569        }
3570    }
3571    list_add(&s->list, &slab_caches);
3572    return s;
3573}
3574
3575void __init kmem_cache_init(void)
3576{
3577    static __initdata struct kmem_cache boot_kmem_cache,
3578        boot_kmem_cache_node;
3579
3580    if (debug_guardpage_minorder())
3581        slub_max_order = 0;
3582
3583    kmem_cache_node = &boot_kmem_cache_node;
3584    kmem_cache = &boot_kmem_cache;
3585
3586    create_boot_cache(kmem_cache_node, "kmem_cache_node",
3587        sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
3588
3589    register_hotmemory_notifier(&slab_memory_callback_nb);
3590
3591    /* Able to allocate the per node structures */
3592    slab_state = PARTIAL;
3593
3594    create_boot_cache(kmem_cache, "kmem_cache",
3595            offsetof(struct kmem_cache, node) +
3596                nr_node_ids * sizeof(struct kmem_cache_node *),
3597               SLAB_HWCACHE_ALIGN);
3598
3599    kmem_cache = bootstrap(&boot_kmem_cache);
3600
3601    /*
3602     * Allocate kmem_cache_node properly from the kmem_cache slab.
3603     * kmem_cache_node is separately allocated so no need to
3604     * update any list pointers.
3605     */
3606    kmem_cache_node = bootstrap(&boot_kmem_cache_node);
3607
3608    /* Now we can use the kmem_cache to allocate kmalloc slabs */
3609    create_kmalloc_caches(0);
3610
3611#ifdef CONFIG_SMP
3612    register_cpu_notifier(&slab_notifier);
3613#endif
3614
3615    printk(KERN_INFO
3616        "SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d,"
3617        " CPUs=%d, Nodes=%d\n",
3618        cache_line_size(),
3619        slub_min_order, slub_max_order, slub_min_objects,
3620        nr_cpu_ids, nr_node_ids);
3621}
3622
3623void __init kmem_cache_init_late(void)
3624{
3625}
3626
3627/*
3628 * Find a mergeable slab cache
3629 */
3630static int slab_unmergeable(struct kmem_cache *s)
3631{
3632    if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3633        return 1;
3634
3635    if (s->ctor)
3636        return 1;
3637
3638    /*
3639     * We may have set a slab to be unmergeable during bootstrap.
3640     */
3641    if (s->refcount < 0)
3642        return 1;
3643
3644    return 0;
3645}
3646
3647static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
3648        size_t align, unsigned long flags, const char *name,
3649        void (*ctor)(void *))
3650{
3651    struct kmem_cache *s;
3652
3653    if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3654        return NULL;
3655
3656    if (ctor)
3657        return NULL;
3658
3659    size = ALIGN(size, sizeof(void *));
3660    align = calculate_alignment(flags, align, size);
3661    size = ALIGN(size, align);
3662    flags = kmem_cache_flags(size, flags, name, NULL);
3663
3664    list_for_each_entry(s, &slab_caches, list) {
3665        if (slab_unmergeable(s))
3666            continue;
3667
3668        if (size > s->size)
3669            continue;
3670
3671        if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3672                continue;
3673        /*
3674         * Check if alignment is compatible.
3675         * Courtesy of Adrian Drzewiecki
3676         */
3677        if ((s->size & ~(align - 1)) != s->size)
3678            continue;
3679
3680        if (s->size - size >= sizeof(void *))
3681            continue;
3682
3683        if (!cache_match_memcg(s, memcg))
3684            continue;
3685
3686        return s;
3687    }
3688    return NULL;
3689}
3690
3691struct kmem_cache *
3692__kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
3693           size_t align, unsigned long flags, void (*ctor)(void *))
3694{
3695    struct kmem_cache *s;
3696
3697    s = find_mergeable(memcg, size, align, flags, name, ctor);
3698    if (s) {
3699        s->refcount++;
3700        /*
3701         * Adjust the object sizes so that we clear
3702         * the complete object on kzalloc.
3703         */
3704        s->object_size = max(s->object_size, (int)size);
3705        s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3706
3707        if (sysfs_slab_alias(s, name)) {
3708            s->refcount--;
3709            s = NULL;
3710        }
3711    }
3712
3713    return s;
3714}
3715
3716int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
3717{
3718    int err;
3719
3720    err = kmem_cache_open(s, flags);
3721    if (err)
3722        return err;
3723
3724    /* Mutex is not taken during early boot */
3725    if (slab_state <= UP)
3726        return 0;
3727
3728    memcg_propagate_slab_attrs(s);
3729    mutex_unlock(&slab_mutex);
3730    err = sysfs_slab_add(s);
3731    mutex_lock(&slab_mutex);
3732
3733    if (err)
3734        kmem_cache_close(s);
3735
3736    return err;
3737}
3738
3739#ifdef CONFIG_SMP
3740/*
3741 * Use the cpu notifier to insure that the cpu slabs are flushed when
3742 * necessary.
3743 */
3744static int slab_cpuup_callback(struct notifier_block *nfb,
3745        unsigned long action, void *hcpu)
3746{
3747    long cpu = (long)hcpu;
3748    struct kmem_cache *s;
3749    unsigned long flags;
3750
3751    switch (action) {
3752    case CPU_UP_CANCELED:
3753    case CPU_UP_CANCELED_FROZEN:
3754    case CPU_DEAD:
3755    case CPU_DEAD_FROZEN:
3756        mutex_lock(&slab_mutex);
3757        list_for_each_entry(s, &slab_caches, list) {
3758            local_irq_save(flags);
3759            __flush_cpu_slab(s, cpu);
3760            local_irq_restore(flags);
3761        }
3762        mutex_unlock(&slab_mutex);
3763        break;
3764    default:
3765        break;
3766    }
3767    return NOTIFY_OK;
3768}
3769
3770static struct notifier_block slab_notifier = {
3771    .notifier_call = slab_cpuup_callback
3772};
3773
3774#endif
3775
3776void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
3777{
3778    struct kmem_cache *s;
3779    void *ret;
3780
3781    if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3782        return kmalloc_large(size, gfpflags);
3783
3784    s = kmalloc_slab(size, gfpflags);
3785
3786    if (unlikely(ZERO_OR_NULL_PTR(s)))
3787        return s;
3788
3789    ret = slab_alloc(s, gfpflags, caller);
3790
3791    /* Honor the call site pointer we received. */
3792    trace_kmalloc(caller, ret, size, s->size, gfpflags);
3793
3794    return ret;
3795}
3796
3797#ifdef CONFIG_NUMA
3798void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3799                    int node, unsigned long caller)
3800{
3801    struct kmem_cache *s;
3802    void *ret;
3803
3804    if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3805        ret = kmalloc_large_node(size, gfpflags, node);
3806
3807        trace_kmalloc_node(caller, ret,
3808                   size, PAGE_SIZE << get_order(size),
3809                   gfpflags, node);
3810
3811        return ret;
3812    }
3813
3814    s = kmalloc_slab(size, gfpflags);
3815
3816    if (unlikely(ZERO_OR_NULL_PTR(s)))
3817        return s;
3818
3819    ret = slab_alloc_node(s, gfpflags, node, caller);
3820
3821    /* Honor the call site pointer we received. */
3822    trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
3823
3824    return ret;
3825}
3826#endif
3827
3828#ifdef CONFIG_SYSFS
3829static int count_inuse(struct page *page)
3830{
3831    return page->inuse;
3832}
3833
3834static int count_total(struct page *page)
3835{
3836    return page->objects;
3837}
3838#endif
3839
3840#ifdef CONFIG_SLUB_DEBUG
3841static int validate_slab(struct kmem_cache *s, struct page *page,
3842                        unsigned long *map)
3843{
3844    void *p;
3845    void *addr = page_address(page);
3846
3847    if (!check_slab(s, page) ||
3848            !on_freelist(s, page, NULL))
3849        return 0;
3850
3851    /* Now we know that a valid freelist exists */
3852    bitmap_zero(map, page->objects);
3853
3854    get_map(s, page, map);
3855    for_each_object(p, s, addr, page->objects) {
3856        if (test_bit(slab_index(p, s, addr), map))
3857            if (!check_object(s, page, p, SLUB_RED_INACTIVE))
3858                return 0;
3859    }
3860
3861    for_each_object(p, s, addr, page->objects)
3862        if (!test_bit(slab_index(p, s, addr), map))
3863            if (!check_object(s, page, p, SLUB_RED_ACTIVE))
3864                return 0;
3865    return 1;
3866}
3867
3868static void validate_slab_slab(struct kmem_cache *s, struct page *page,
3869                        unsigned long *map)
3870{
3871    slab_lock(page);
3872    validate_slab(s, page, map);
3873    slab_unlock(page);
3874}
3875
3876static int validate_slab_node(struct kmem_cache *s,
3877        struct kmem_cache_node *n, unsigned long *map)
3878{
3879    unsigned long count = 0;
3880    struct page *page;
3881    unsigned long flags;
3882
3883    spin_lock_irqsave(&n->list_lock, flags);
3884
3885    list_for_each_entry(page, &n->partial, lru) {
3886        validate_slab_slab(s, page, map);
3887        count++;
3888    }
3889    if (count != n->nr_partial)
3890        printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
3891            "counter=%ld\n", s->name, count, n->nr_partial);
3892
3893    if (!(s->flags & SLAB_STORE_USER))
3894        goto out;
3895
3896    list_for_each_entry(page, &n->full, lru) {
3897        validate_slab_slab(s, page, map);
3898        count++;
3899    }
3900    if (count != atomic_long_read(&n->nr_slabs))
3901        printk(KERN_ERR "SLUB: %s %ld slabs counted but "
3902            "counter=%ld\n", s->name, count,
3903            atomic_long_read(&n->nr_slabs));
3904
3905out:
3906    spin_unlock_irqrestore(&n->list_lock, flags);
3907    return count;
3908}
3909
3910static long validate_slab_cache(struct kmem_cache *s)
3911{
3912    int node;
3913    unsigned long count = 0;
3914    unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
3915                sizeof(unsigned long), GFP_KERNEL);
3916
3917    if (!map)
3918        return -ENOMEM;
3919
3920    flush_all(s);
3921    for_each_node_state(node, N_NORMAL_MEMORY) {
3922        struct kmem_cache_node *n = get_node(s, node);
3923
3924        count += validate_slab_node(s, n, map);
3925    }
3926    kfree(map);
3927    return count;
3928}
3929/*
3930 * Generate lists of code addresses where slabcache objects are allocated
3931 * and freed.
3932 */
3933
3934struct location {
3935    unsigned long count;
3936    unsigned long addr;
3937    long long sum_time;
3938    long min_time;
3939    long max_time;
3940    long min_pid;
3941    long max_pid;
3942    DECLARE_BITMAP(cpus, NR_CPUS);
3943    nodemask_t nodes;
3944};
3945
3946struct loc_track {
3947    unsigned long max;
3948    unsigned long count;
3949    struct location *loc;
3950};
3951
3952static void free_loc_track(struct loc_track *t)
3953{
3954    if (t->max)
3955        free_pages((unsigned long)t->loc,
3956            get_order(sizeof(struct location) * t->max));
3957}
3958
3959static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
3960{
3961    struct location *l;
3962    int order;
3963
3964    order = get_order(sizeof(struct location) * max);
3965
3966    l = (void *)__get_free_pages(flags, order);
3967    if (!l)
3968        return 0;
3969
3970    if (t->count) {
3971        memcpy(l, t->loc, sizeof(struct location) * t->count);
3972        free_loc_track(t);
3973    }
3974    t->max = max;
3975    t->loc = l;
3976    return 1;
3977}
3978
3979static int add_location(struct loc_track *t, struct kmem_cache *s,
3980                const struct track *track)
3981{
3982    long start, end, pos;
3983    struct location *l;
3984    unsigned long caddr;
3985    unsigned long age = jiffies - track->when;
3986
3987    start = -1;
3988    end = t->count;
3989
3990    for ( ; ; ) {
3991        pos = start + (end - start + 1) / 2;
3992
3993        /*
3994         * There is nothing at "end". If we end up there
3995         * we need to add something to before end.
3996         */
3997        if (pos == end)
3998            break;
3999
4000        caddr = t->loc[pos].addr;
4001        if (track->addr == caddr) {
4002
4003            l = &t->loc[pos];
4004            l->count++;
4005            if (track->when) {
4006                l->sum_time += age;
4007                if (age < l->min_time)
4008                    l->min_time = age;
4009                if (age > l->max_time)
4010                    l->max_time = age;
4011
4012                if (track->pid < l->min_pid)
4013                    l->min_pid = track->pid;
4014                if (track->pid > l->max_pid)
4015                    l->max_pid = track->pid;
4016
4017                cpumask_set_cpu(track->cpu,
4018                        to_cpumask(l->cpus));
4019            }
4020            node_set(page_to_nid(virt_to_page(track)), l->nodes);
4021            return 1;
4022        }
4023
4024        if (track->addr < caddr)
4025            end = pos;
4026        else
4027            start = pos;
4028    }
4029
4030    /*
4031     * Not found. Insert new tracking element.
4032     */
4033    if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4034        return 0;
4035
4036    l = t->loc + pos;
4037    if (pos < t->count)
4038        memmove(l + 1, l,
4039            (t->count - pos) * sizeof(struct location));
4040    t->count++;
4041    l->count = 1;
4042    l->addr = track->addr;
4043    l->sum_time = age;
4044    l->min_time = age;
4045    l->max_time = age;
4046    l->min_pid = track->pid;
4047    l->max_pid = track->pid;
4048    cpumask_clear(to_cpumask(l->cpus));
4049    cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4050    nodes_clear(l->nodes);
4051    node_set(page_to_nid(virt_to_page(track)), l->nodes);
4052    return 1;
4053}
4054
4055static void process_slab(struct loc_track *t, struct kmem_cache *s,
4056        struct page *page, enum track_item alloc,
4057        unsigned long *map)
4058{
4059    void *addr = page_address(page);
4060    void *p;
4061
4062    bitmap_zero(map, page->objects);
4063    get_map(s, page, map);
4064
4065    for_each_object(p, s, addr, page->objects)
4066        if (!test_bit(slab_index(p, s, addr), map))
4067            add_location(t, s, get_track(s, p, alloc));
4068}
4069
4070static int list_locations(struct kmem_cache *s, char *buf,
4071                    enum track_item alloc)
4072{
4073    int len = 0;
4074    unsigned long i;
4075    struct loc_track t = { 0, 0, NULL };
4076    int node;
4077    unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4078                     sizeof(unsigned long), GFP_KERNEL);
4079
4080    if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4081                     GFP_TEMPORARY)) {
4082        kfree(map);
4083        return sprintf(buf, "Out of memory\n");
4084    }
4085    /* Push back cpu slabs */
4086    flush_all(s);
4087
4088    for_each_node_state(node, N_NORMAL_MEMORY) {
4089        struct kmem_cache_node *n = get_node(s, node);
4090        unsigned long flags;
4091        struct page *page;
4092
4093        if (!atomic_long_read(&n->nr_slabs))
4094            continue;
4095
4096        spin_lock_irqsave(&n->list_lock, flags);
4097        list_for_each_entry(page, &n->partial, lru)
4098            process_slab(&t, s, page, alloc, map);
4099        list_for_each_entry(page, &n->full, lru)
4100            process_slab(&t, s, page, alloc, map);
4101        spin_unlock_irqrestore(&n->list_lock, flags);
4102    }
4103
4104    for (i = 0; i < t.count; i++) {
4105        struct location *l = &t.loc[i];
4106
4107        if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4108            break;
4109        len += sprintf(buf + len, "%7ld ", l->count);
4110
4111        if (l->addr)
4112            len += sprintf(buf + len, "%pS", (void *)l->addr);
4113        else
4114            len += sprintf(buf + len, "<not-available>");
4115
4116        if (l->sum_time != l->min_time) {
4117            len += sprintf(buf + len, " age=%ld/%ld/%ld",
4118                l->min_time,
4119                (long)div_u64(l->sum_time, l->count),
4120                l->max_time);
4121        } else
4122            len += sprintf(buf + len, " age=%ld",
4123                l->min_time);
4124
4125        if (l->min_pid != l->max_pid)
4126            len += sprintf(buf + len, " pid=%ld-%ld",
4127                l->min_pid, l->max_pid);
4128        else
4129            len += sprintf(buf + len, " pid=%ld",
4130                l->min_pid);
4131
4132        if (num_online_cpus() > 1 &&
4133                !cpumask_empty(to_cpumask(l->cpus)) &&
4134                len < PAGE_SIZE - 60) {
4135            len += sprintf(buf + len, " cpus=");
4136            len += cpulist_scnprintf(buf + len,
4137                         PAGE_SIZE - len - 50,
4138                         to_cpumask(l->cpus));
4139        }
4140
4141        if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4142                len < PAGE_SIZE - 60) {
4143            len += sprintf(buf + len, " nodes=");
4144            len += nodelist_scnprintf(buf + len,
4145                          PAGE_SIZE - len - 50,
4146                          l->nodes);
4147        }
4148
4149        len += sprintf(buf + len, "\n");
4150    }
4151
4152    free_loc_track(&t);
4153    kfree(map);
4154    if (!t.count)
4155        len += sprintf(buf, "No data\n");
4156    return len;
4157}
4158#endif
4159
4160#ifdef SLUB_RESILIENCY_TEST
4161static void resiliency_test(void)
4162{
4163    u8 *p;
4164
4165    BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4166
4167    printk(KERN_ERR "SLUB resiliency testing\n");
4168    printk(KERN_ERR "-----------------------\n");
4169    printk(KERN_ERR "A. Corruption after allocation\n");
4170
4171    p = kzalloc(16, GFP_KERNEL);
4172    p[16] = 0x12;
4173    printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
4174            " 0x12->0x%p\n\n", p + 16);
4175
4176    validate_slab_cache(kmalloc_caches[4]);
4177
4178    /* Hmmm... The next two are dangerous */
4179    p = kzalloc(32, GFP_KERNEL);
4180    p[32 + sizeof(void *)] = 0x34;
4181    printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
4182            " 0x34 -> -0x%p\n", p);
4183    printk(KERN_ERR
4184        "If allocated object is overwritten then not detectable\n\n");
4185
4186    validate_slab_cache(kmalloc_caches[5]);
4187    p = kzalloc(64, GFP_KERNEL);
4188    p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4189    *p = 0x56;
4190    printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4191                                    p);
4192    printk(KERN_ERR
4193        "If allocated object is overwritten then not detectable\n\n");
4194    validate_slab_cache(kmalloc_caches[6]);
4195
4196    printk(KERN_ERR "\nB. Corruption after free\n");
4197    p = kzalloc(128, GFP_KERNEL);
4198    kfree(p);
4199    *p = 0x78;
4200    printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4201    validate_slab_cache(kmalloc_caches[7]);
4202
4203    p = kzalloc(256, GFP_KERNEL);
4204    kfree(p);
4205    p[50] = 0x9a;
4206    printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4207            p);
4208    validate_slab_cache(kmalloc_caches[8]);
4209
4210    p = kzalloc(512, GFP_KERNEL);
4211    kfree(p);
4212    p[512] = 0xab;
4213    printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4214    validate_slab_cache(kmalloc_caches[9]);
4215}
4216#else
4217#ifdef CONFIG_SYSFS
4218static void resiliency_test(void) {};
4219#endif
4220#endif
4221
4222#ifdef CONFIG_SYSFS
4223enum slab_stat_type {
4224    SL_ALL, /* All slabs */
4225    SL_PARTIAL, /* Only partially allocated slabs */
4226    SL_CPU, /* Only slabs used for cpu caches */
4227    SL_OBJECTS, /* Determine allocated objects not slabs */
4228    SL_TOTAL /* Determine object capacity not slabs */
4229};
4230
4231#define SO_ALL (1 << SL_ALL)
4232#define SO_PARTIAL (1 << SL_PARTIAL)
4233#define SO_CPU (1 << SL_CPU)
4234#define SO_OBJECTS (1 << SL_OBJECTS)
4235#define SO_TOTAL (1 << SL_TOTAL)
4236
4237static ssize_t show_slab_objects(struct kmem_cache *s,
4238                char *buf, unsigned long flags)
4239{
4240    unsigned long total = 0;
4241    int node;
4242    int x;
4243    unsigned long *nodes;
4244
4245    nodes = kzalloc(sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4246    if (!nodes)
4247        return -ENOMEM;
4248
4249    if (flags & SO_CPU) {
4250        int cpu;
4251
4252        for_each_possible_cpu(cpu) {
4253            struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4254                                   cpu);
4255            int node;
4256            struct page *page;
4257
4258            page = ACCESS_ONCE(c->page);
4259            if (!page)
4260                continue;
4261
4262            node = page_to_nid(page);
4263            if (flags & SO_TOTAL)
4264                x = page->objects;
4265            else if (flags & SO_OBJECTS)
4266                x = page->inuse;
4267            else
4268                x = 1;
4269
4270            total += x;
4271            nodes[node] += x;
4272
4273            page = ACCESS_ONCE(c->partial);
4274            if (page) {
4275                x = page->pobjects;
4276                total += x;
4277                nodes[node] += x;
4278            }
4279        }
4280    }
4281
4282    lock_memory_hotplug();
4283#ifdef CONFIG_SLUB_DEBUG
4284    if (flags & SO_ALL) {
4285        for_each_node_state(node, N_NORMAL_MEMORY) {
4286            struct kmem_cache_node *n = get_node(s, node);
4287
4288            if (flags & SO_TOTAL)
4289                x = atomic_long_read(&n->total_objects);
4290            else if (flags & SO_OBJECTS)
4291                x = atomic_long_read(&n->total_objects) -
4292                    count_partial(n, count_free);
4293            else
4294                x = atomic_long_read(&n->nr_slabs);
4295            total += x;
4296            nodes[node] += x;
4297        }
4298
4299    } else
4300#endif
4301    if (flags & SO_PARTIAL) {
4302        for_each_node_state(node, N_NORMAL_MEMORY) {
4303            struct kmem_cache_node *n = get_node(s, node);
4304
4305            if (flags & SO_TOTAL)
4306                x = count_partial(n, count_total);
4307            else if (flags & SO_OBJECTS)
4308                x = count_partial(n, count_inuse);
4309            else
4310                x = n->nr_partial;
4311            total += x;
4312            nodes[node] += x;
4313        }
4314    }
4315    x = sprintf(buf, "%lu", total);
4316#ifdef CONFIG_NUMA
4317    for_each_node_state(node, N_NORMAL_MEMORY)
4318        if (nodes[node])
4319            x += sprintf(buf + x, " N%d=%lu",
4320                    node, nodes[node]);
4321#endif
4322    unlock_memory_hotplug();
4323    kfree(nodes);
4324    return x + sprintf(buf + x, "\n");
4325}
4326
4327#ifdef CONFIG_SLUB_DEBUG
4328static int any_slab_objects(struct kmem_cache *s)
4329{
4330    int node;
4331
4332    for_each_online_node(node) {
4333        struct kmem_cache_node *n = get_node(s, node);
4334
4335        if (!n)
4336            continue;
4337
4338        if (atomic_long_read(&n->total_objects))
4339            return 1;
4340    }
4341    return 0;
4342}
4343#endif
4344
4345#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4346#define to_slab(n) container_of(n, struct kmem_cache, kobj)
4347
4348struct slab_attribute {
4349    struct attribute attr;
4350    ssize_t (*show)(struct kmem_cache *s, char *buf);
4351    ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4352};
4353
4354#define SLAB_ATTR_RO(_name) \
4355    static struct slab_attribute _name##_attr = \
4356    __ATTR(_name, 0400, _name##_show, NULL)
4357
4358#define SLAB_ATTR(_name) \
4359    static struct slab_attribute _name##_attr = \
4360    __ATTR(_name, 0600, _name##_show, _name##_store)
4361
4362static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4363{
4364    return sprintf(buf, "%d\n", s->size);
4365}
4366SLAB_ATTR_RO(slab_size);
4367
4368static ssize_t align_show(struct kmem_cache *s, char *buf)
4369{
4370    return sprintf(buf, "%d\n", s->align);
4371}
4372SLAB_ATTR_RO(align);
4373
4374static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4375{
4376    return sprintf(buf, "%d\n", s->object_size);
4377}
4378SLAB_ATTR_RO(object_size);
4379
4380static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4381{
4382    return sprintf(buf, "%d\n", oo_objects(s->oo));
4383}
4384SLAB_ATTR_RO(objs_per_slab);
4385
4386static ssize_t order_store(struct kmem_cache *s,
4387                const char *buf, size_t length)
4388{
4389    unsigned long order;
4390    int err;
4391
4392    err = kstrtoul(buf, 10, &order);
4393    if (err)
4394        return err;
4395
4396    if (order > slub_max_order || order < slub_min_order)
4397        return -EINVAL;
4398
4399    calculate_sizes(s, order);
4400    return length;
4401}
4402
4403static ssize_t order_show(struct kmem_cache *s, char *buf)
4404{
4405    return sprintf(buf, "%d\n", oo_order(s->oo));
4406}
4407SLAB_ATTR(order);
4408
4409static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4410{
4411    return sprintf(buf, "%lu\n", s->min_partial);
4412}
4413
4414static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4415                 size_t length)
4416{
4417    unsigned long min;
4418    int err;
4419
4420    err = kstrtoul(buf, 10, &min);
4421    if (err)
4422        return err;
4423
4424    set_min_partial(s, min);
4425    return length;
4426}
4427SLAB_ATTR(min_partial);
4428
4429static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4430{
4431    return sprintf(buf, "%u\n", s->cpu_partial);
4432}
4433
4434static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4435                 size_t length)
4436{
4437    unsigned long objects;
4438    int err;
4439
4440    err = kstrtoul(buf, 10, &objects);
4441    if (err)
4442        return err;
4443    if (objects && !kmem_cache_has_cpu_partial(s))
4444        return -EINVAL;
4445
4446    s->cpu_partial = objects;
4447    flush_all(s);
4448    return length;
4449}
4450SLAB_ATTR(cpu_partial);
4451
4452static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4453{
4454    if (!s->ctor)
4455        return 0;
4456    return sprintf(buf, "%pS\n", s->ctor);
4457}
4458SLAB_ATTR_RO(ctor);
4459
4460static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4461{
4462    return sprintf(buf, "%d\n", s->refcount - 1);
4463}
4464SLAB_ATTR_RO(aliases);
4465
4466static ssize_t partial_show(struct kmem_cache *s, char *buf)
4467{
4468    return show_slab_objects(s, buf, SO_PARTIAL);
4469}
4470SLAB_ATTR_RO(partial);
4471
4472static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4473{
4474    return show_slab_objects(s, buf, SO_CPU);
4475}
4476SLAB_ATTR_RO(cpu_slabs);
4477
4478static ssize_t objects_show(struct kmem_cache *s, char *buf)
4479{
4480    return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4481}
4482SLAB_ATTR_RO(objects);
4483
4484static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4485{
4486    return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4487}
4488SLAB_ATTR_RO(objects_partial);
4489
4490static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4491{
4492    int objects = 0;
4493    int pages = 0;
4494    int cpu;
4495    int len;
4496
4497    for_each_online_cpu(cpu) {
4498        struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4499
4500        if (page) {
4501            pages += page->pages;
4502            objects += page->pobjects;
4503        }
4504    }
4505
4506    len = sprintf(buf, "%d(%d)", objects, pages);
4507
4508#ifdef CONFIG_SMP
4509    for_each_online_cpu(cpu) {
4510        struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4511
4512        if (page && len < PAGE_SIZE - 20)
4513            len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4514                page->pobjects, page->pages);
4515    }
4516#endif
4517    return len + sprintf(buf + len, "\n");
4518}
4519SLAB_ATTR_RO(slabs_cpu_partial);
4520
4521static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4522{
4523    return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4524}
4525
4526static ssize_t reclaim_account_store(struct kmem_cache *s,
4527                const char *buf, size_t length)
4528{
4529    s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4530    if (buf[0] == '1')
4531        s->flags |= SLAB_RECLAIM_ACCOUNT;
4532    return length;
4533}
4534SLAB_ATTR(reclaim_account);
4535
4536static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4537{
4538    return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4539}
4540SLAB_ATTR_RO(hwcache_align);
4541
4542#ifdef CONFIG_ZONE_DMA
4543static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4544{
4545    return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4546}
4547SLAB_ATTR_RO(cache_dma);
4548#endif
4549
4550static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4551{
4552    return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4553}
4554SLAB_ATTR_RO(destroy_by_rcu);
4555
4556static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4557{
4558    return sprintf(buf, "%d\n", s->reserved);
4559}
4560SLAB_ATTR_RO(reserved);
4561
4562#ifdef CONFIG_SLUB_DEBUG
4563static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4564{
4565    return show_slab_objects(s, buf, SO_ALL);
4566}
4567SLAB_ATTR_RO(slabs);
4568
4569static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4570{
4571    return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4572}
4573SLAB_ATTR_RO(total_objects);
4574
4575static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4576{
4577    return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4578}
4579
4580static ssize_t sanity_checks_store(struct kmem_cache *s,
4581                const char *buf, size_t length)
4582{
4583    s->flags &= ~SLAB_DEBUG_FREE;
4584    if (buf[0] == '1') {
4585        s->flags &= ~__CMPXCHG_DOUBLE;
4586        s->flags |= SLAB_DEBUG_FREE;
4587    }
4588    return length;
4589}
4590SLAB_ATTR(sanity_checks);
4591
4592static ssize_t trace_show(struct kmem_cache *s, char *buf)
4593{
4594    return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4595}
4596
4597static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4598                            size_t length)
4599{
4600    s->flags &= ~SLAB_TRACE;
4601    if (buf[0] == '1') {
4602        s->flags &= ~__CMPXCHG_DOUBLE;
4603        s->flags |= SLAB_TRACE;
4604    }
4605    return length;
4606}
4607SLAB_ATTR(trace);
4608
4609static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4610{
4611    return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4612}
4613
4614static ssize_t red_zone_store(struct kmem_cache *s,
4615                const char *buf, size_t length)
4616{
4617    if (any_slab_objects(s))
4618        return -EBUSY;
4619
4620    s->flags &= ~SLAB_RED_ZONE;
4621    if (buf[0] == '1') {
4622        s->flags &= ~__CMPXCHG_DOUBLE;
4623        s->flags |= SLAB_RED_ZONE;
4624    }
4625    calculate_sizes(s, -1);
4626    return length;
4627}
4628SLAB_ATTR(red_zone);
4629
4630static ssize_t poison_show(struct kmem_cache *s, char *buf)
4631{
4632    return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4633}
4634
4635static ssize_t poison_store(struct kmem_cache *s,
4636                const char *buf, size_t length)
4637{
4638    if (any_slab_objects(s))
4639        return -EBUSY;
4640
4641    s->flags &= ~SLAB_POISON;
4642    if (buf[0] == '1') {
4643        s->flags &= ~__CMPXCHG_DOUBLE;
4644        s->flags |= SLAB_POISON;
4645    }
4646    calculate_sizes(s, -1);
4647    return length;
4648}
4649SLAB_ATTR(poison);
4650
4651static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4652{
4653    return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4654}
4655
4656static ssize_t store_user_store(struct kmem_cache *s,
4657                const char *buf, size_t length)
4658{
4659    if (any_slab_objects(s))
4660        return -EBUSY;
4661
4662    s->flags &= ~SLAB_STORE_USER;
4663    if (buf[0] == '1') {
4664        s->flags &= ~__CMPXCHG_DOUBLE;
4665        s->flags |= SLAB_STORE_USER;
4666    }
4667    calculate_sizes(s, -1);
4668    return length;
4669}
4670SLAB_ATTR(store_user);
4671
4672static ssize_t validate_show(struct kmem_cache *s, char *buf)
4673{
4674    return 0;
4675}
4676
4677static ssize_t validate_store(struct kmem_cache *s,
4678            const char *buf, size_t length)
4679{
4680    int ret = -EINVAL;
4681
4682    if (buf[0] == '1') {
4683        ret = validate_slab_cache(s);
4684        if (ret >= 0)
4685            ret = length;
4686    }
4687    return ret;
4688}
4689SLAB_ATTR(validate);
4690
4691static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4692{
4693    if (!(s->flags & SLAB_STORE_USER))
4694        return -ENOSYS;
4695    return list_locations(s, buf, TRACK_ALLOC);
4696}
4697SLAB_ATTR_RO(alloc_calls);
4698
4699static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4700{
4701    if (!(s->flags & SLAB_STORE_USER))
4702        return -ENOSYS;
4703    return list_locations(s, buf, TRACK_FREE);
4704}
4705SLAB_ATTR_RO(free_calls);
4706#endif /* CONFIG_SLUB_DEBUG */
4707
4708#ifdef CONFIG_FAILSLAB
4709static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4710{
4711    return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4712}
4713
4714static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4715                            size_t length)
4716{
4717    s->flags &= ~SLAB_FAILSLAB;
4718    if (buf[0] == '1')
4719        s->flags |= SLAB_FAILSLAB;
4720    return length;
4721}
4722SLAB_ATTR(failslab);
4723#endif
4724
4725static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4726{
4727    return 0;
4728}
4729
4730static ssize_t shrink_store(struct kmem_cache *s,
4731            const char *buf, size_t length)
4732{
4733    if (buf[0] == '1') {
4734        int rc = kmem_cache_shrink(s);
4735
4736        if (rc)
4737            return rc;
4738    } else
4739        return -EINVAL;
4740    return length;
4741}
4742SLAB_ATTR(shrink);
4743
4744#ifdef CONFIG_NUMA
4745static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4746{
4747    return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4748}
4749
4750static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
4751                const char *buf, size_t length)
4752{
4753    unsigned long ratio;
4754    int err;
4755
4756    err = kstrtoul(buf, 10, &ratio);
4757    if (err)
4758        return err;
4759
4760    if (ratio <= 100)
4761        s->remote_node_defrag_ratio = ratio * 10;
4762
4763    return length;
4764}
4765SLAB_ATTR(remote_node_defrag_ratio);
4766#endif
4767
4768#ifdef CONFIG_SLUB_STATS
4769static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
4770{
4771    unsigned long sum = 0;
4772    int cpu;
4773    int len;
4774    int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
4775
4776    if (!data)
4777        return -ENOMEM;
4778
4779    for_each_online_cpu(cpu) {
4780        unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
4781
4782        data[cpu] = x;
4783        sum += x;
4784    }
4785
4786    len = sprintf(buf, "%lu", sum);
4787
4788#ifdef CONFIG_SMP
4789    for_each_online_cpu(cpu) {
4790        if (data[cpu] && len < PAGE_SIZE - 20)
4791            len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
4792    }
4793#endif
4794    kfree(data);
4795    return len + sprintf(buf + len, "\n");
4796}
4797
4798static void clear_stat(struct kmem_cache *s, enum stat_item si)
4799{
4800    int cpu;
4801
4802    for_each_online_cpu(cpu)
4803        per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
4804}
4805
4806#define STAT_ATTR(si, text) \
4807static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4808{ \
4809    return show_stat(s, buf, si); \
4810} \
4811static ssize_t text##_store(struct kmem_cache *s, \
4812                const char *buf, size_t length) \
4813{ \
4814    if (buf[0] != '0') \
4815        return -EINVAL; \
4816    clear_stat(s, si); \
4817    return length; \
4818} \
4819SLAB_ATTR(text); \
4820
4821STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4822STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
4823STAT_ATTR(FREE_FASTPATH, free_fastpath);
4824STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4825STAT_ATTR(FREE_FROZEN, free_frozen);
4826STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4827STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4828STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4829STAT_ATTR(ALLOC_SLAB, alloc_slab);
4830STAT_ATTR(ALLOC_REFILL, alloc_refill);
4831STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
4832STAT_ATTR(FREE_SLAB, free_slab);
4833STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4834STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4835STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4836STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4837STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4838STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4839STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
4840STAT_ATTR(ORDER_FALLBACK, order_fallback);
4841STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
4842STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
4843STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
4844STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
4845STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
4846STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
4847#endif
4848
4849static struct attribute *slab_attrs[] = {
4850    &slab_size_attr.attr,
4851    &object_size_attr.attr,
4852    &objs_per_slab_attr.attr,
4853    &order_attr.attr,
4854    &min_partial_attr.attr,
4855    &cpu_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    &slabs_cpu_partial_attr.attr,
4869#ifdef CONFIG_SLUB_DEBUG
4870    &total_objects_attr.attr,
4871    &slabs_attr.attr,
4872    &sanity_checks_attr.attr,
4873    &trace_attr.attr,
4874    &red_zone_attr.attr,
4875    &poison_attr.attr,
4876    &store_user_attr.attr,
4877    &validate_attr.attr,
4878    &alloc_calls_attr.attr,
4879    &free_calls_attr.attr,
4880#endif
4881#ifdef CONFIG_ZONE_DMA
4882    &cache_dma_attr.attr,
4883#endif
4884#ifdef CONFIG_NUMA
4885    &remote_node_defrag_ratio_attr.attr,
4886#endif
4887#ifdef CONFIG_SLUB_STATS
4888    &alloc_fastpath_attr.attr,
4889    &alloc_slowpath_attr.attr,
4890    &free_fastpath_attr.attr,
4891    &free_slowpath_attr.attr,
4892    &free_frozen_attr.attr,
4893    &free_add_partial_attr.attr,
4894    &free_remove_partial_attr.attr,
4895    &alloc_from_partial_attr.attr,
4896    &alloc_slab_attr.attr,
4897    &alloc_refill_attr.attr,
4898    &alloc_node_mismatch_attr.attr,
4899    &free_slab_attr.attr,
4900    &cpuslab_flush_attr.attr,
4901    &deactivate_full_attr.attr,
4902    &deactivate_empty_attr.attr,
4903    &deactivate_to_head_attr.attr,
4904    &deactivate_to_tail_attr.attr,
4905    &deactivate_remote_frees_attr.attr,
4906    &deactivate_bypass_attr.attr,
4907    &order_fallback_attr.attr,
4908    &cmpxchg_double_fail_attr.attr,
4909    &cmpxchg_double_cpu_fail_attr.attr,
4910    &cpu_partial_alloc_attr.attr,
4911    &cpu_partial_free_attr.attr,
4912    &cpu_partial_node_attr.attr,
4913    &cpu_partial_drain_attr.attr,
4914#endif
4915#ifdef CONFIG_FAILSLAB
4916    &failslab_attr.attr,
4917#endif
4918
4919    NULL
4920};
4921
4922static struct attribute_group slab_attr_group = {
4923    .attrs = slab_attrs,
4924};
4925
4926static ssize_t slab_attr_show(struct kobject *kobj,
4927                struct attribute *attr,
4928                char *buf)
4929{
4930    struct slab_attribute *attribute;
4931    struct kmem_cache *s;
4932    int err;
4933
4934    attribute = to_slab_attr(attr);
4935    s = to_slab(kobj);
4936
4937    if (!attribute->show)
4938        return -EIO;
4939
4940    err = attribute->show(s, buf);
4941
4942    return err;
4943}
4944
4945static ssize_t slab_attr_store(struct kobject *kobj,
4946                struct attribute *attr,
4947                const char *buf, size_t len)
4948{
4949    struct slab_attribute *attribute;
4950    struct kmem_cache *s;
4951    int err;
4952
4953    attribute = to_slab_attr(attr);
4954    s = to_slab(kobj);
4955
4956    if (!attribute->store)
4957        return -EIO;
4958
4959    err = attribute->store(s, buf, len);
4960#ifdef CONFIG_MEMCG_KMEM
4961    if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
4962        int i;
4963
4964        mutex_lock(&slab_mutex);
4965        if (s->max_attr_size < len)
4966            s->max_attr_size = len;
4967
4968        /*
4969         * This is a best effort propagation, so this function's return
4970         * value will be determined by the parent cache only. This is
4971         * basically because not all attributes will have a well
4972         * defined semantics for rollbacks - most of the actions will
4973         * have permanent effects.
4974         *
4975         * Returning the error value of any of the children that fail
4976         * is not 100 % defined, in the sense that users seeing the
4977         * error code won't be able to know anything about the state of
4978         * the cache.
4979         *
4980         * Only returning the error code for the parent cache at least
4981         * has well defined semantics. The cache being written to
4982         * directly either failed or succeeded, in which case we loop
4983         * through the descendants with best-effort propagation.
4984         */
4985        for_each_memcg_cache_index(i) {
4986            struct kmem_cache *c = cache_from_memcg(s, i);
4987            if (c)
4988                attribute->store(c, buf, len);
4989        }
4990        mutex_unlock(&slab_mutex);
4991    }
4992#endif
4993    return err;
4994}
4995
4996static void memcg_propagate_slab_attrs(struct kmem_cache *s)
4997{
4998#ifdef CONFIG_MEMCG_KMEM
4999    int i;
5000    char *buffer = NULL;
5001
5002    if (!is_root_cache(s))
5003        return;
5004
5005    /*
5006     * This mean this cache had no attribute written. Therefore, no point
5007     * in copying default values around
5008     */
5009    if (!s->max_attr_size)
5010        return;
5011
5012    for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5013        char mbuf[64];
5014        char *buf;
5015        struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5016
5017        if (!attr || !attr->store || !attr->show)
5018            continue;
5019
5020        /*
5021         * It is really bad that we have to allocate here, so we will
5022         * do it only as a fallback. If we actually allocate, though,
5023         * we can just use the allocated buffer until the end.
5024         *
5025         * Most of the slub attributes will tend to be very small in
5026         * size, but sysfs allows buffers up to a page, so they can
5027         * theoretically happen.
5028         */
5029        if (buffer)
5030            buf = buffer;
5031        else if (s->max_attr_size < ARRAY_SIZE(mbuf))
5032            buf = mbuf;
5033        else {
5034            buffer = (char *) get_zeroed_page(GFP_KERNEL);
5035            if (WARN_ON(!buffer))
5036                continue;
5037            buf = buffer;
5038        }
5039
5040        attr->show(s->memcg_params->root_cache, buf);
5041        attr->store(s, buf, strlen(buf));
5042    }
5043
5044    if (buffer)
5045        free_page((unsigned long)buffer);
5046#endif
5047}
5048
5049static const struct sysfs_ops slab_sysfs_ops = {
5050    .show = slab_attr_show,
5051    .store = slab_attr_store,
5052};
5053
5054static struct kobj_type slab_ktype = {
5055    .sysfs_ops = &slab_sysfs_ops,
5056};
5057
5058static int uevent_filter(struct kset *kset, struct kobject *kobj)
5059{
5060    struct kobj_type *ktype = get_ktype(kobj);
5061
5062    if (ktype == &slab_ktype)
5063        return 1;
5064    return 0;
5065}
5066
5067static const struct kset_uevent_ops slab_uevent_ops = {
5068    .filter = uevent_filter,
5069};
5070
5071static struct kset *slab_kset;
5072
5073#define ID_STR_LENGTH 64
5074
5075/* Create a unique string id for a slab cache:
5076 *
5077 * Format :[flags-]size
5078 */
5079static char *create_unique_id(struct kmem_cache *s)
5080{
5081    char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5082    char *p = name;
5083
5084    BUG_ON(!name);
5085
5086    *p++ = ':';
5087    /*
5088     * First flags affecting slabcache operations. We will only
5089     * get here for aliasable slabs so we do not need to support
5090     * too many flags. The flags here must cover all flags that
5091     * are matched during merging to guarantee that the id is
5092     * unique.
5093     */
5094    if (s->flags & SLAB_CACHE_DMA)
5095        *p++ = 'd';
5096    if (s->flags & SLAB_RECLAIM_ACCOUNT)
5097        *p++ = 'a';
5098    if (s->flags & SLAB_DEBUG_FREE)
5099        *p++ = 'F';
5100    if (!(s->flags & SLAB_NOTRACK))
5101        *p++ = 't';
5102    if (p != name + 1)
5103        *p++ = '-';
5104    p += sprintf(p, "%07d", s->size);
5105
5106#ifdef CONFIG_MEMCG_KMEM
5107    if (!is_root_cache(s))
5108        p += sprintf(p, "-%08d",
5109                memcg_cache_id(s->memcg_params->memcg));
5110#endif
5111
5112    BUG_ON(p > name + ID_STR_LENGTH - 1);
5113    return name;
5114}
5115
5116static int sysfs_slab_add(struct kmem_cache *s)
5117{
5118    int err;
5119    const char *name;
5120    int unmergeable = slab_unmergeable(s);
5121
5122    if (unmergeable) {
5123        /*
5124         * Slabcache can never be merged so we can use the name proper.
5125         * This is typically the case for debug situations. In that
5126         * case we can catch duplicate names easily.
5127         */
5128        sysfs_remove_link(&slab_kset->kobj, s->name);
5129        name = s->name;
5130    } else {
5131        /*
5132         * Create a unique name for the slab as a target
5133         * for the symlinks.
5134         */
5135        name = create_unique_id(s);
5136    }
5137
5138    s->kobj.kset = slab_kset;
5139    err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
5140    if (err) {
5141        kobject_put(&s->kobj);
5142        return err;
5143    }
5144
5145    err = sysfs_create_group(&s->kobj, &slab_attr_group);
5146    if (err) {
5147        kobject_del(&s->kobj);
5148        kobject_put(&s->kobj);
5149        return err;
5150    }
5151    kobject_uevent(&s->kobj, KOBJ_ADD);
5152    if (!unmergeable) {
5153        /* Setup first alias */
5154        sysfs_slab_alias(s, s->name);
5155        kfree(name);
5156    }
5157    return 0;
5158}
5159
5160static void sysfs_slab_remove(struct kmem_cache *s)
5161{
5162    if (slab_state < FULL)
5163        /*
5164         * Sysfs has not been setup yet so no need to remove the
5165         * cache from sysfs.
5166         */
5167        return;
5168
5169    kobject_uevent(&s->kobj, KOBJ_REMOVE);
5170    kobject_del(&s->kobj);
5171    kobject_put(&s->kobj);
5172}
5173
5174/*
5175 * Need to buffer aliases during bootup until sysfs becomes
5176 * available lest we lose that information.
5177 */
5178struct saved_alias {
5179    struct kmem_cache *s;
5180    const char *name;
5181    struct saved_alias *next;
5182};
5183
5184static struct saved_alias *alias_list;
5185
5186static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5187{
5188    struct saved_alias *al;
5189
5190    if (slab_state == FULL) {
5191        /*
5192         * If we have a leftover link then remove it.
5193         */
5194        sysfs_remove_link(&slab_kset->kobj, name);
5195        return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5196    }
5197
5198    al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5199    if (!al)
5200        return -ENOMEM;
5201
5202    al->s = s;
5203    al->name = name;
5204    al->next = alias_list;
5205    alias_list = al;
5206    return 0;
5207}
5208
5209static int __init slab_sysfs_init(void)
5210{
5211    struct kmem_cache *s;
5212    int err;
5213
5214    mutex_lock(&slab_mutex);
5215
5216    slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5217    if (!slab_kset) {
5218        mutex_unlock(&slab_mutex);
5219        printk(KERN_ERR "Cannot register slab subsystem.\n");
5220        return -ENOSYS;
5221    }
5222
5223    slab_state = FULL;
5224
5225    list_for_each_entry(s, &slab_caches, list) {
5226        err = sysfs_slab_add(s);
5227        if (err)
5228            printk(KERN_ERR "SLUB: Unable to add boot slab %s"
5229                        " to sysfs\n", s->name);
5230    }
5231
5232    while (alias_list) {
5233        struct saved_alias *al = alias_list;
5234
5235        alias_list = alias_list->next;
5236        err = sysfs_slab_alias(al->s, al->name);
5237        if (err)
5238            printk(KERN_ERR "SLUB: Unable to add boot slab alias"
5239                    " %s to sysfs\n", al->name);
5240        kfree(al);
5241    }
5242
5243    mutex_unlock(&slab_mutex);
5244    resiliency_test();
5245    return 0;
5246}
5247
5248__initcall(slab_sysfs_init);
5249#endif /* CONFIG_SYSFS */
5250
5251/*
5252 * The /proc/slabinfo ABI
5253 */
5254#ifdef CONFIG_SLABINFO
5255void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5256{
5257    unsigned long nr_slabs = 0;
5258    unsigned long nr_objs = 0;
5259    unsigned long nr_free = 0;
5260    int node;
5261
5262    for_each_online_node(node) {
5263        struct kmem_cache_node *n = get_node(s, node);
5264
5265        if (!n)
5266            continue;
5267
5268        nr_slabs += node_nr_slabs(n);
5269        nr_objs += node_nr_objs(n);
5270        nr_free += count_partial(n, count_free);
5271    }
5272
5273    sinfo->active_objs = nr_objs - nr_free;
5274    sinfo->num_objs = nr_objs;
5275    sinfo->active_slabs = nr_slabs;
5276    sinfo->num_slabs = nr_slabs;
5277    sinfo->objects_per_slab = oo_objects(s->oo);
5278    sinfo->cache_order = oo_order(s->oo);
5279}
5280
5281void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5282{
5283}
5284
5285ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5286               size_t count, loff_t *ppos)
5287{
5288    return -EIO;
5289}
5290#endif /* CONFIG_SLABINFO */
5291

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