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/seq_file.h>
22#include <linux/kmemcheck.h>
23#include <linux/cpu.h>
24#include <linux/cpuset.h>
25#include <linux/mempolicy.h>
26#include <linux/ctype.h>
27#include <linux/debugobjects.h>
28#include <linux/kallsyms.h>
29#include <linux/memory.h>
30#include <linux/math64.h>
31#include <linux/fault-inject.h>
32#include <linux/stacktrace.h>
33#include <linux/prefetch.h>
34#include <linux/memcontrol.h>
35
36#include <trace/events/kmem.h>
37
38#include "internal.h"
39
40/*
41 * Lock order:
42 * 1. slab_mutex (Global Mutex)
43 * 2. node->list_lock
44 * 3. slab_lock(page) (Only on some arches and for debugging)
45 *
46 * slab_mutex
47 *
48 * The role of the slab_mutex is to protect the list of all the slabs
49 * and to synchronize major metadata changes to slab cache structures.
50 *
51 * The slab_lock is only used for debugging and on arches that do not
52 * have the ability to do a cmpxchg_double. It only protects the second
53 * double word in the page struct. Meaning
54 * A. page->freelist -> List of object free in a page
55 * B. page->counters -> Counters of objects
56 * C. page->frozen -> frozen state
57 *
58 * If a slab is frozen then it is exempt from list management. It is not
59 * on any list. The processor that froze the slab is the one who can
60 * perform list operations on the page. Other processors may put objects
61 * onto the freelist but the processor that froze the slab is the only
62 * one that can retrieve the objects from the page's freelist.
63 *
64 * The list_lock protects the partial and full list on each node and
65 * the partial slab counter. If taken then no new slabs may be added or
66 * removed from the lists nor make the number of partial slabs be modified.
67 * (Note that the total number of slabs is an atomic value that may be
68 * modified without taking the list lock).
69 *
70 * The list_lock is a centralized lock and thus we avoid taking it as
71 * much as possible. As long as SLUB does not have to handle partial
72 * slabs, operations can continue without any centralized lock. F.e.
73 * allocating a long series of objects that fill up slabs does not require
74 * the list lock.
75 * Interrupts are disabled during allocation and deallocation in order to
76 * make the slab allocator safe to use in the context of an irq. In addition
77 * interrupts are disabled to ensure that the processor does not change
78 * while handling per_cpu slabs, due to kernel preemption.
79 *
80 * SLUB assigns one slab for allocation to each processor.
81 * Allocations only occur from these slabs called cpu slabs.
82 *
83 * Slabs with free elements are kept on a partial list and during regular
84 * operations no list for full slabs is used. If an object in a full slab is
85 * freed then the slab will show up again on the partial lists.
86 * We track full slabs for debugging purposes though because otherwise we
87 * cannot scan all objects.
88 *
89 * Slabs are freed when they become empty. Teardown and setup is
90 * minimal so we rely on the page allocators per cpu caches for
91 * fast frees and allocs.
92 *
93 * Overloading of page flags that are otherwise used for LRU management.
94 *
95 * PageActive The slab is frozen and exempt from list processing.
96 * This means that the slab is dedicated to a purpose
97 * such as satisfying allocations for a specific
98 * processor. Objects may be freed in the slab while
99 * it is frozen but slab_free will then skip the usual
100 * list operations. It is up to the processor holding
101 * the slab to integrate the slab into the slab lists
102 * when the slab is no longer needed.
103 *
104 * One use of this flag is to mark slabs that are
105 * used for allocations. Then such a slab becomes a cpu
106 * slab. The cpu slab may be equipped with an additional
107 * freelist that allows lockless access to
108 * free objects in addition to the regular freelist
109 * that requires the slab lock.
110 *
111 * PageError Slab requires special handling due to debug
112 * options set. This moves slab handling out of
113 * the fast path and disables lockless freelists.
114 */
115
116static inline int kmem_cache_debug(struct kmem_cache *s)
117{
118#ifdef CONFIG_SLUB_DEBUG
119    return unlikely(s->flags & SLAB_DEBUG_FLAGS);
120#else
121    return 0;
122#endif
123}
124
125/*
126 * Issues still to be resolved:
127 *
128 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
129 *
130 * - Variable sizing of the per node arrays
131 */
132
133/* Enable to test recovery from slab corruption on boot */
134#undef SLUB_RESILIENCY_TEST
135
136/* Enable to log cmpxchg failures */
137#undef SLUB_DEBUG_CMPXCHG
138
139/*
140 * Mininum number of partial slabs. These will be left on the partial
141 * lists even if they are empty. kmem_cache_shrink may reclaim them.
142 */
143#define MIN_PARTIAL 5
144
145/*
146 * Maximum number of desirable partial slabs.
147 * The existence of more partial slabs makes kmem_cache_shrink
148 * sort the partial list by the number of objects in the.
149 */
150#define MAX_PARTIAL 10
151
152#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
153                SLAB_POISON | SLAB_STORE_USER)
154
155/*
156 * Debugging flags that require metadata to be stored in the slab. These get
157 * disabled when slub_debug=O is used and a cache's min order increases with
158 * metadata.
159 */
160#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
161
162/*
163 * Set of flags that will prevent slab merging
164 */
165#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
166        SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
167        SLAB_FAILSLAB)
168
169#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
170        SLAB_CACHE_DMA | SLAB_NOTRACK)
171
172#define OO_SHIFT 16
173#define OO_MASK ((1 << OO_SHIFT) - 1)
174#define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
175
176/* Internal SLUB flags */
177#define __OBJECT_POISON 0x80000000UL /* Poison object */
178#define __CMPXCHG_DOUBLE 0x40000000UL /* Use cmpxchg_double */
179
180#ifdef CONFIG_SMP
181static struct notifier_block slab_notifier;
182#endif
183
184/*
185 * Tracking user of a slab.
186 */
187#define TRACK_ADDRS_COUNT 16
188struct track {
189    unsigned long addr; /* Called from address */
190#ifdef CONFIG_STACKTRACE
191    unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
192#endif
193    int cpu; /* Was running on cpu */
194    int pid; /* Pid context */
195    unsigned long when; /* When did the operation occur */
196};
197
198enum track_item { TRACK_ALLOC, TRACK_FREE };
199
200#ifdef CONFIG_SYSFS
201static int sysfs_slab_add(struct kmem_cache *);
202static int sysfs_slab_alias(struct kmem_cache *, const char *);
203static void sysfs_slab_remove(struct kmem_cache *);
204static void memcg_propagate_slab_attrs(struct kmem_cache *s);
205#else
206static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
207static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
208                            { return 0; }
209static inline void sysfs_slab_remove(struct kmem_cache *s) { }
210
211static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
212#endif
213
214static inline void stat(const struct kmem_cache *s, enum stat_item si)
215{
216#ifdef CONFIG_SLUB_STATS
217    __this_cpu_inc(s->cpu_slab->stat[si]);
218#endif
219}
220
221/********************************************************************
222 * Core slab cache functions
223 *******************************************************************/
224
225static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
226{
227    return s->node[node];
228}
229
230/* Verify that a pointer has an address that is valid within a slab page */
231static inline int check_valid_pointer(struct kmem_cache *s,
232                struct page *page, const void *object)
233{
234    void *base;
235
236    if (!object)
237        return 1;
238
239    base = page_address(page);
240    if (object < base || object >= base + page->objects * s->size ||
241        (object - base) % s->size) {
242        return 0;
243    }
244
245    return 1;
246}
247
248static inline void *get_freepointer(struct kmem_cache *s, void *object)
249{
250    return *(void **)(object + s->offset);
251}
252
253static void prefetch_freepointer(const struct kmem_cache *s, void *object)
254{
255    prefetch(object + s->offset);
256}
257
258static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
259{
260    void *p;
261
262#ifdef CONFIG_DEBUG_PAGEALLOC
263    probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
264#else
265    p = get_freepointer(s, object);
266#endif
267    return p;
268}
269
270static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
271{
272    *(void **)(object + s->offset) = fp;
273}
274
275/* Loop over all objects in a slab */
276#define for_each_object(__p, __s, __addr, __objects) \
277    for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
278            __p += (__s)->size)
279
280/* Determine object index from a given position */
281static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
282{
283    return (p - addr) / s->size;
284}
285
286static inline size_t slab_ksize(const struct kmem_cache *s)
287{
288#ifdef CONFIG_SLUB_DEBUG
289    /*
290     * Debugging requires use of the padding between object
291     * and whatever may come after it.
292     */
293    if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
294        return s->object_size;
295
296#endif
297    /*
298     * If we have the need to store the freelist pointer
299     * back there or track user information then we can
300     * only use the space before that information.
301     */
302    if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
303        return s->inuse;
304    /*
305     * Else we can use all the padding etc for the allocation
306     */
307    return s->size;
308}
309
310static inline int order_objects(int order, unsigned long size, int reserved)
311{
312    return ((PAGE_SIZE << order) - reserved) / size;
313}
314
315static inline struct kmem_cache_order_objects oo_make(int order,
316        unsigned long size, int reserved)
317{
318    struct kmem_cache_order_objects x = {
319        (order << OO_SHIFT) + order_objects(order, size, reserved)
320    };
321
322    return x;
323}
324
325static inline int oo_order(struct kmem_cache_order_objects x)
326{
327    return x.x >> OO_SHIFT;
328}
329
330static inline int oo_objects(struct kmem_cache_order_objects x)
331{
332    return x.x & OO_MASK;
333}
334
335/*
336 * Per slab locking using the pagelock
337 */
338static __always_inline void slab_lock(struct page *page)
339{
340    bit_spin_lock(PG_locked, &page->flags);
341}
342
343static __always_inline void slab_unlock(struct page *page)
344{
345    __bit_spin_unlock(PG_locked, &page->flags);
346}
347
348/* Interrupts must be disabled (for the fallback code to work right) */
349static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
350        void *freelist_old, unsigned long counters_old,
351        void *freelist_new, unsigned long counters_new,
352        const char *n)
353{
354    VM_BUG_ON(!irqs_disabled());
355#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
356    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
357    if (s->flags & __CMPXCHG_DOUBLE) {
358        if (cmpxchg_double(&page->freelist, &page->counters,
359            freelist_old, counters_old,
360            freelist_new, counters_new))
361        return 1;
362    } else
363#endif
364    {
365        slab_lock(page);
366        if (page->freelist == freelist_old && page->counters == counters_old) {
367            page->freelist = freelist_new;
368            page->counters = counters_new;
369            slab_unlock(page);
370            return 1;
371        }
372        slab_unlock(page);
373    }
374
375    cpu_relax();
376    stat(s, CMPXCHG_DOUBLE_FAIL);
377
378#ifdef SLUB_DEBUG_CMPXCHG
379    printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
380#endif
381
382    return 0;
383}
384
385static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
386        void *freelist_old, unsigned long counters_old,
387        void *freelist_new, unsigned long counters_new,
388        const char *n)
389{
390#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
391    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
392    if (s->flags & __CMPXCHG_DOUBLE) {
393        if (cmpxchg_double(&page->freelist, &page->counters,
394            freelist_old, counters_old,
395            freelist_new, counters_new))
396        return 1;
397    } else
398#endif
399    {
400        unsigned long flags;
401
402        local_irq_save(flags);
403        slab_lock(page);
404        if (page->freelist == freelist_old && page->counters == counters_old) {
405            page->freelist = freelist_new;
406            page->counters = counters_new;
407            slab_unlock(page);
408            local_irq_restore(flags);
409            return 1;
410        }
411        slab_unlock(page);
412        local_irq_restore(flags);
413    }
414
415    cpu_relax();
416    stat(s, CMPXCHG_DOUBLE_FAIL);
417
418#ifdef SLUB_DEBUG_CMPXCHG
419    printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
420#endif
421
422    return 0;
423}
424
425#ifdef CONFIG_SLUB_DEBUG
426/*
427 * Determine a map of object in use on a page.
428 *
429 * Node listlock must be held to guarantee that the page does
430 * not vanish from under us.
431 */
432static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
433{
434    void *p;
435    void *addr = page_address(page);
436
437    for (p = page->freelist; p; p = get_freepointer(s, p))
438        set_bit(slab_index(p, s, addr), map);
439}
440
441/*
442 * Debug settings:
443 */
444#ifdef CONFIG_SLUB_DEBUG_ON
445static int slub_debug = DEBUG_DEFAULT_FLAGS;
446#else
447static int slub_debug;
448#endif
449
450static char *slub_debug_slabs;
451static int disable_higher_order_debug;
452
453/*
454 * Object debugging
455 */
456static void print_section(char *text, u8 *addr, unsigned int length)
457{
458    print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
459            length, 1);
460}
461
462static struct track *get_track(struct kmem_cache *s, void *object,
463    enum track_item alloc)
464{
465    struct track *p;
466
467    if (s->offset)
468        p = object + s->offset + sizeof(void *);
469    else
470        p = object + s->inuse;
471
472    return p + alloc;
473}
474
475static void set_track(struct kmem_cache *s, void *object,
476            enum track_item alloc, unsigned long addr)
477{
478    struct track *p = get_track(s, object, alloc);
479
480    if (addr) {
481#ifdef CONFIG_STACKTRACE
482        struct stack_trace trace;
483        int i;
484
485        trace.nr_entries = 0;
486        trace.max_entries = TRACK_ADDRS_COUNT;
487        trace.entries = p->addrs;
488        trace.skip = 3;
489        save_stack_trace(&trace);
490
491        /* See rant in lockdep.c */
492        if (trace.nr_entries != 0 &&
493            trace.entries[trace.nr_entries - 1] == ULONG_MAX)
494            trace.nr_entries--;
495
496        for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
497            p->addrs[i] = 0;
498#endif
499        p->addr = addr;
500        p->cpu = smp_processor_id();
501        p->pid = current->pid;
502        p->when = jiffies;
503    } else
504        memset(p, 0, sizeof(struct track));
505}
506
507static void init_tracking(struct kmem_cache *s, void *object)
508{
509    if (!(s->flags & SLAB_STORE_USER))
510        return;
511
512    set_track(s, object, TRACK_FREE, 0UL);
513    set_track(s, object, TRACK_ALLOC, 0UL);
514}
515
516static void print_track(const char *s, struct track *t)
517{
518    if (!t->addr)
519        return;
520
521    printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
522        s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
523#ifdef CONFIG_STACKTRACE
524    {
525        int i;
526        for (i = 0; i < TRACK_ADDRS_COUNT; i++)
527            if (t->addrs[i])
528                printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
529            else
530                break;
531    }
532#endif
533}
534
535static void print_tracking(struct kmem_cache *s, void *object)
536{
537    if (!(s->flags & SLAB_STORE_USER))
538        return;
539
540    print_track("Allocated", get_track(s, object, TRACK_ALLOC));
541    print_track("Freed", get_track(s, object, TRACK_FREE));
542}
543
544static void print_page_info(struct page *page)
545{
546    printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
547        page, page->objects, page->inuse, page->freelist, page->flags);
548
549}
550
551static void slab_bug(struct kmem_cache *s, char *fmt, ...)
552{
553    va_list args;
554    char buf[100];
555
556    va_start(args, fmt);
557    vsnprintf(buf, sizeof(buf), fmt, args);
558    va_end(args);
559    printk(KERN_ERR "========================================"
560            "=====================================\n");
561    printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
562    printk(KERN_ERR "----------------------------------------"
563            "-------------------------------------\n\n");
564
565    add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
566}
567
568static void slab_fix(struct kmem_cache *s, char *fmt, ...)
569{
570    va_list args;
571    char buf[100];
572
573    va_start(args, fmt);
574    vsnprintf(buf, sizeof(buf), fmt, args);
575    va_end(args);
576    printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
577}
578
579static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
580{
581    unsigned int off; /* Offset of last byte */
582    u8 *addr = page_address(page);
583
584    print_tracking(s, p);
585
586    print_page_info(page);
587
588    printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
589            p, p - addr, get_freepointer(s, p));
590
591    if (p > addr + 16)
592        print_section("Bytes b4 ", p - 16, 16);
593
594    print_section("Object ", p, min_t(unsigned long, s->object_size,
595                PAGE_SIZE));
596    if (s->flags & SLAB_RED_ZONE)
597        print_section("Redzone ", p + s->object_size,
598            s->inuse - s->object_size);
599
600    if (s->offset)
601        off = s->offset + sizeof(void *);
602    else
603        off = s->inuse;
604
605    if (s->flags & SLAB_STORE_USER)
606        off += 2 * sizeof(struct track);
607
608    if (off != s->size)
609        /* Beginning of the filler is the free pointer */
610        print_section("Padding ", p + off, s->size - off);
611
612    dump_stack();
613}
614
615static void object_err(struct kmem_cache *s, struct page *page,
616            u8 *object, char *reason)
617{
618    slab_bug(s, "%s", reason);
619    print_trailer(s, page, object);
620}
621
622static void slab_err(struct kmem_cache *s, struct page *page, const char *fmt, ...)
623{
624    va_list args;
625    char buf[100];
626
627    va_start(args, fmt);
628    vsnprintf(buf, sizeof(buf), fmt, args);
629    va_end(args);
630    slab_bug(s, "%s", buf);
631    print_page_info(page);
632    dump_stack();
633}
634
635static void init_object(struct kmem_cache *s, void *object, u8 val)
636{
637    u8 *p = object;
638
639    if (s->flags & __OBJECT_POISON) {
640        memset(p, POISON_FREE, s->object_size - 1);
641        p[s->object_size - 1] = POISON_END;
642    }
643
644    if (s->flags & SLAB_RED_ZONE)
645        memset(p + s->object_size, val, s->inuse - s->object_size);
646}
647
648static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
649                        void *from, void *to)
650{
651    slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
652    memset(from, data, to - from);
653}
654
655static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
656            u8 *object, char *what,
657            u8 *start, unsigned int value, unsigned int bytes)
658{
659    u8 *fault;
660    u8 *end;
661
662    fault = memchr_inv(start, value, bytes);
663    if (!fault)
664        return 1;
665
666    end = start + bytes;
667    while (end > fault && end[-1] == value)
668        end--;
669
670    slab_bug(s, "%s overwritten", what);
671    printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
672                    fault, end - 1, fault[0], value);
673    print_trailer(s, page, object);
674
675    restore_bytes(s, what, value, fault, end);
676    return 0;
677}
678
679/*
680 * Object layout:
681 *
682 * object address
683 * Bytes of the object to be managed.
684 * If the freepointer may overlay the object then the free
685 * pointer is the first word of the object.
686 *
687 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
688 * 0xa5 (POISON_END)
689 *
690 * object + s->object_size
691 * Padding to reach word boundary. This is also used for Redzoning.
692 * Padding is extended by another word if Redzoning is enabled and
693 * object_size == inuse.
694 *
695 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
696 * 0xcc (RED_ACTIVE) for objects in use.
697 *
698 * object + s->inuse
699 * Meta data starts here.
700 *
701 * A. Free pointer (if we cannot overwrite object on free)
702 * B. Tracking data for SLAB_STORE_USER
703 * C. Padding to reach required alignment boundary or at mininum
704 * one word if debugging is on to be able to detect writes
705 * before the word boundary.
706 *
707 * Padding is done using 0x5a (POISON_INUSE)
708 *
709 * object + s->size
710 * Nothing is used beyond s->size.
711 *
712 * If slabcaches are merged then the object_size and inuse boundaries are mostly
713 * ignored. And therefore no slab options that rely on these boundaries
714 * may be used with merged slabcaches.
715 */
716
717static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
718{
719    unsigned long off = s->inuse; /* The end of info */
720
721    if (s->offset)
722        /* Freepointer is placed after the object. */
723        off += sizeof(void *);
724
725    if (s->flags & SLAB_STORE_USER)
726        /* We also have user information there */
727        off += 2 * sizeof(struct track);
728
729    if (s->size == off)
730        return 1;
731
732    return check_bytes_and_report(s, page, p, "Object padding",
733                p + off, POISON_INUSE, s->size - off);
734}
735
736/* Check the pad bytes at the end of a slab page */
737static int slab_pad_check(struct kmem_cache *s, struct page *page)
738{
739    u8 *start;
740    u8 *fault;
741    u8 *end;
742    int length;
743    int remainder;
744
745    if (!(s->flags & SLAB_POISON))
746        return 1;
747
748    start = page_address(page);
749    length = (PAGE_SIZE << compound_order(page)) - s->reserved;
750    end = start + length;
751    remainder = length % s->size;
752    if (!remainder)
753        return 1;
754
755    fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
756    if (!fault)
757        return 1;
758    while (end > fault && end[-1] == POISON_INUSE)
759        end--;
760
761    slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
762    print_section("Padding ", end - remainder, remainder);
763
764    restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
765    return 0;
766}
767
768static int check_object(struct kmem_cache *s, struct page *page,
769                    void *object, u8 val)
770{
771    u8 *p = object;
772    u8 *endobject = object + s->object_size;
773
774    if (s->flags & SLAB_RED_ZONE) {
775        if (!check_bytes_and_report(s, page, object, "Redzone",
776            endobject, val, s->inuse - s->object_size))
777            return 0;
778    } else {
779        if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
780            check_bytes_and_report(s, page, p, "Alignment padding",
781                endobject, POISON_INUSE, s->inuse - s->object_size);
782        }
783    }
784
785    if (s->flags & SLAB_POISON) {
786        if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
787            (!check_bytes_and_report(s, page, p, "Poison", p,
788                    POISON_FREE, s->object_size - 1) ||
789             !check_bytes_and_report(s, page, p, "Poison",
790                p + s->object_size - 1, POISON_END, 1)))
791            return 0;
792        /*
793         * check_pad_bytes cleans up on its own.
794         */
795        check_pad_bytes(s, page, p);
796    }
797
798    if (!s->offset && val == SLUB_RED_ACTIVE)
799        /*
800         * Object and freepointer overlap. Cannot check
801         * freepointer while object is allocated.
802         */
803        return 1;
804
805    /* Check free pointer validity */
806    if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
807        object_err(s, page, p, "Freepointer corrupt");
808        /*
809         * No choice but to zap it and thus lose the remainder
810         * of the free objects in this slab. May cause
811         * another error because the object count is now wrong.
812         */
813        set_freepointer(s, p, NULL);
814        return 0;
815    }
816    return 1;
817}
818
819static int check_slab(struct kmem_cache *s, struct page *page)
820{
821    int maxobj;
822
823    VM_BUG_ON(!irqs_disabled());
824
825    if (!PageSlab(page)) {
826        slab_err(s, page, "Not a valid slab page");
827        return 0;
828    }
829
830    maxobj = order_objects(compound_order(page), s->size, s->reserved);
831    if (page->objects > maxobj) {
832        slab_err(s, page, "objects %u > max %u",
833            s->name, page->objects, maxobj);
834        return 0;
835    }
836    if (page->inuse > page->objects) {
837        slab_err(s, page, "inuse %u > max %u",
838            s->name, page->inuse, page->objects);
839        return 0;
840    }
841    /* Slab_pad_check fixes things up after itself */
842    slab_pad_check(s, page);
843    return 1;
844}
845
846/*
847 * Determine if a certain object on a page is on the freelist. Must hold the
848 * slab lock to guarantee that the chains are in a consistent state.
849 */
850static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
851{
852    int nr = 0;
853    void *fp;
854    void *object = NULL;
855    unsigned long max_objects;
856
857    fp = page->freelist;
858    while (fp && nr <= page->objects) {
859        if (fp == search)
860            return 1;
861        if (!check_valid_pointer(s, page, fp)) {
862            if (object) {
863                object_err(s, page, object,
864                    "Freechain corrupt");
865                set_freepointer(s, object, NULL);
866                break;
867            } else {
868                slab_err(s, page, "Freepointer corrupt");
869                page->freelist = NULL;
870                page->inuse = page->objects;
871                slab_fix(s, "Freelist cleared");
872                return 0;
873            }
874            break;
875        }
876        object = fp;
877        fp = get_freepointer(s, object);
878        nr++;
879    }
880
881    max_objects = order_objects(compound_order(page), s->size, s->reserved);
882    if (max_objects > MAX_OBJS_PER_PAGE)
883        max_objects = MAX_OBJS_PER_PAGE;
884
885    if (page->objects != max_objects) {
886        slab_err(s, page, "Wrong number of objects. Found %d but "
887            "should be %d", page->objects, max_objects);
888        page->objects = max_objects;
889        slab_fix(s, "Number of objects adjusted.");
890    }
891    if (page->inuse != page->objects - nr) {
892        slab_err(s, page, "Wrong object count. Counter is %d but "
893            "counted were %d", page->inuse, page->objects - nr);
894        page->inuse = page->objects - nr;
895        slab_fix(s, "Object count adjusted.");
896    }
897    return search == NULL;
898}
899
900static void trace(struct kmem_cache *s, struct page *page, void *object,
901                                int alloc)
902{
903    if (s->flags & SLAB_TRACE) {
904        printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
905            s->name,
906            alloc ? "alloc" : "free",
907            object, page->inuse,
908            page->freelist);
909
910        if (!alloc)
911            print_section("Object ", (void *)object, s->object_size);
912
913        dump_stack();
914    }
915}
916
917/*
918 * Hooks for other subsystems that check memory allocations. In a typical
919 * production configuration these hooks all should produce no code at all.
920 */
921static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
922{
923    flags &= gfp_allowed_mask;
924    lockdep_trace_alloc(flags);
925    might_sleep_if(flags & __GFP_WAIT);
926
927    return should_failslab(s->object_size, flags, s->flags);
928}
929
930static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
931{
932    flags &= gfp_allowed_mask;
933    kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
934    kmemleak_alloc_recursive(object, s->object_size, 1, s->flags, flags);
935}
936
937static inline void slab_free_hook(struct kmem_cache *s, void *x)
938{
939    kmemleak_free_recursive(x, s->flags);
940
941    /*
942     * Trouble is that we may no longer disable interupts in the fast path
943     * So in order to make the debug calls that expect irqs to be
944     * disabled we need to disable interrupts temporarily.
945     */
946#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
947    {
948        unsigned long flags;
949
950        local_irq_save(flags);
951        kmemcheck_slab_free(s, x, s->object_size);
952        debug_check_no_locks_freed(x, s->object_size);
953        local_irq_restore(flags);
954    }
955#endif
956    if (!(s->flags & SLAB_DEBUG_OBJECTS))
957        debug_check_no_obj_freed(x, s->object_size);
958}
959
960/*
961 * Tracking of fully allocated slabs for debugging purposes.
962 *
963 * list_lock must be held.
964 */
965static void add_full(struct kmem_cache *s,
966    struct kmem_cache_node *n, struct page *page)
967{
968    if (!(s->flags & SLAB_STORE_USER))
969        return;
970
971    list_add(&page->lru, &n->full);
972}
973
974/*
975 * list_lock must be held.
976 */
977static void remove_full(struct kmem_cache *s, struct page *page)
978{
979    if (!(s->flags & SLAB_STORE_USER))
980        return;
981
982    list_del(&page->lru);
983}
984
985/* Tracking of the number of slabs for debugging purposes */
986static inline unsigned long slabs_node(struct kmem_cache *s, int node)
987{
988    struct kmem_cache_node *n = get_node(s, node);
989
990    return atomic_long_read(&n->nr_slabs);
991}
992
993static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
994{
995    return atomic_long_read(&n->nr_slabs);
996}
997
998static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
999{
1000    struct kmem_cache_node *n = get_node(s, node);
1001
1002    /*
1003     * May be called early in order to allocate a slab for the
1004     * kmem_cache_node structure. Solve the chicken-egg
1005     * dilemma by deferring the increment of the count during
1006     * bootstrap (see early_kmem_cache_node_alloc).
1007     */
1008    if (n) {
1009        atomic_long_inc(&n->nr_slabs);
1010        atomic_long_add(objects, &n->total_objects);
1011    }
1012}
1013static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1014{
1015    struct kmem_cache_node *n = get_node(s, node);
1016
1017    atomic_long_dec(&n->nr_slabs);
1018    atomic_long_sub(objects, &n->total_objects);
1019}
1020
1021/* Object debug checks for alloc/free paths */
1022static void setup_object_debug(struct kmem_cache *s, struct page *page,
1023                                void *object)
1024{
1025    if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1026        return;
1027
1028    init_object(s, object, SLUB_RED_INACTIVE);
1029    init_tracking(s, object);
1030}
1031
1032static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
1033                    void *object, unsigned long addr)
1034{
1035    if (!check_slab(s, page))
1036        goto bad;
1037
1038    if (!check_valid_pointer(s, page, object)) {
1039        object_err(s, page, object, "Freelist Pointer check fails");
1040        goto bad;
1041    }
1042
1043    if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1044        goto bad;
1045
1046    /* Success perform special debug activities for allocs */
1047    if (s->flags & SLAB_STORE_USER)
1048        set_track(s, object, TRACK_ALLOC, addr);
1049    trace(s, page, object, 1);
1050    init_object(s, object, SLUB_RED_ACTIVE);
1051    return 1;
1052
1053bad:
1054    if (PageSlab(page)) {
1055        /*
1056         * If this is a slab page then lets do the best we can
1057         * to avoid issues in the future. Marking all objects
1058         * as used avoids touching the remaining objects.
1059         */
1060        slab_fix(s, "Marking all objects used");
1061        page->inuse = page->objects;
1062        page->freelist = NULL;
1063    }
1064    return 0;
1065}
1066
1067static noinline struct kmem_cache_node *free_debug_processing(
1068    struct kmem_cache *s, struct page *page, void *object,
1069    unsigned long addr, unsigned long *flags)
1070{
1071    struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1072
1073    spin_lock_irqsave(&n->list_lock, *flags);
1074    slab_lock(page);
1075
1076    if (!check_slab(s, page))
1077        goto fail;
1078
1079    if (!check_valid_pointer(s, page, object)) {
1080        slab_err(s, page, "Invalid object pointer 0x%p", object);
1081        goto fail;
1082    }
1083
1084    if (on_freelist(s, page, object)) {
1085        object_err(s, page, object, "Object already free");
1086        goto fail;
1087    }
1088
1089    if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1090        goto out;
1091
1092    if (unlikely(s != page->slab_cache)) {
1093        if (!PageSlab(page)) {
1094            slab_err(s, page, "Attempt to free object(0x%p) "
1095                "outside of slab", object);
1096        } else if (!page->slab_cache) {
1097            printk(KERN_ERR
1098                "SLUB <none>: no slab for object 0x%p.\n",
1099                        object);
1100            dump_stack();
1101        } else
1102            object_err(s, page, object,
1103                    "page slab pointer corrupt.");
1104        goto fail;
1105    }
1106
1107    if (s->flags & SLAB_STORE_USER)
1108        set_track(s, object, TRACK_FREE, addr);
1109    trace(s, page, object, 0);
1110    init_object(s, object, SLUB_RED_INACTIVE);
1111out:
1112    slab_unlock(page);
1113    /*
1114     * Keep node_lock to preserve integrity
1115     * until the object is actually freed
1116     */
1117    return n;
1118
1119fail:
1120    slab_unlock(page);
1121    spin_unlock_irqrestore(&n->list_lock, *flags);
1122    slab_fix(s, "Object at 0x%p not freed", object);
1123    return NULL;
1124}
1125
1126static int __init setup_slub_debug(char *str)
1127{
1128    slub_debug = DEBUG_DEFAULT_FLAGS;
1129    if (*str++ != '=' || !*str)
1130        /*
1131         * No options specified. Switch on full debugging.
1132         */
1133        goto out;
1134
1135    if (*str == ',')
1136        /*
1137         * No options but restriction on slabs. This means full
1138         * debugging for slabs matching a pattern.
1139         */
1140        goto check_slabs;
1141
1142    if (tolower(*str) == 'o') {
1143        /*
1144         * Avoid enabling debugging on caches if its minimum order
1145         * would increase as a result.
1146         */
1147        disable_higher_order_debug = 1;
1148        goto out;
1149    }
1150
1151    slub_debug = 0;
1152    if (*str == '-')
1153        /*
1154         * Switch off all debugging measures.
1155         */
1156        goto out;
1157
1158    /*
1159     * Determine which debug features should be switched on
1160     */
1161    for (; *str && *str != ','; str++) {
1162        switch (tolower(*str)) {
1163        case 'f':
1164            slub_debug |= SLAB_DEBUG_FREE;
1165            break;
1166        case 'z':
1167            slub_debug |= SLAB_RED_ZONE;
1168            break;
1169        case 'p':
1170            slub_debug |= SLAB_POISON;
1171            break;
1172        case 'u':
1173            slub_debug |= SLAB_STORE_USER;
1174            break;
1175        case 't':
1176            slub_debug |= SLAB_TRACE;
1177            break;
1178        case 'a':
1179            slub_debug |= SLAB_FAILSLAB;
1180            break;
1181        default:
1182            printk(KERN_ERR "slub_debug option '%c' "
1183                "unknown. skipped\n", *str);
1184        }
1185    }
1186
1187check_slabs:
1188    if (*str == ',')
1189        slub_debug_slabs = str + 1;
1190out:
1191    return 1;
1192}
1193
1194__setup("slub_debug", setup_slub_debug);
1195
1196static unsigned long kmem_cache_flags(unsigned long object_size,
1197    unsigned long flags, const char *name,
1198    void (*ctor)(void *))
1199{
1200    /*
1201     * Enable debugging if selected on the kernel commandline.
1202     */
1203    if (slub_debug && (!slub_debug_slabs ||
1204        !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
1205        flags |= slub_debug;
1206
1207    return flags;
1208}
1209#else
1210static inline void setup_object_debug(struct kmem_cache *s,
1211            struct page *page, void *object) {}
1212
1213static inline int alloc_debug_processing(struct kmem_cache *s,
1214    struct page *page, void *object, unsigned long addr) { return 0; }
1215
1216static inline struct kmem_cache_node *free_debug_processing(
1217    struct kmem_cache *s, struct page *page, void *object,
1218    unsigned long addr, unsigned long *flags) { return NULL; }
1219
1220static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1221            { return 1; }
1222static inline int check_object(struct kmem_cache *s, struct page *page,
1223            void *object, u8 val) { return 1; }
1224static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1225                    struct page *page) {}
1226static inline void remove_full(struct kmem_cache *s, struct page *page) {}
1227static inline unsigned long kmem_cache_flags(unsigned long object_size,
1228    unsigned long flags, const char *name,
1229    void (*ctor)(void *))
1230{
1231    return flags;
1232}
1233#define slub_debug 0
1234
1235#define disable_higher_order_debug 0
1236
1237static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1238                            { return 0; }
1239static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1240                            { return 0; }
1241static inline void inc_slabs_node(struct kmem_cache *s, int node,
1242                            int objects) {}
1243static inline void dec_slabs_node(struct kmem_cache *s, int node,
1244                            int objects) {}
1245
1246static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1247                            { return 0; }
1248
1249static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
1250        void *object) {}
1251
1252static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
1253
1254#endif /* CONFIG_SLUB_DEBUG */
1255
1256/*
1257 * Slab allocation and freeing
1258 */
1259static inline struct page *alloc_slab_page(gfp_t flags, int node,
1260                    struct kmem_cache_order_objects oo)
1261{
1262    int order = oo_order(oo);
1263
1264    flags |= __GFP_NOTRACK;
1265
1266    if (node == NUMA_NO_NODE)
1267        return alloc_pages(flags, order);
1268    else
1269        return alloc_pages_exact_node(node, flags, order);
1270}
1271
1272static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1273{
1274    struct page *page;
1275    struct kmem_cache_order_objects oo = s->oo;
1276    gfp_t alloc_gfp;
1277
1278    flags &= gfp_allowed_mask;
1279
1280    if (flags & __GFP_WAIT)
1281        local_irq_enable();
1282
1283    flags |= s->allocflags;
1284
1285    /*
1286     * Let the initial higher-order allocation fail under memory pressure
1287     * so we fall-back to the minimum order allocation.
1288     */
1289    alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1290
1291    page = alloc_slab_page(alloc_gfp, node, oo);
1292    if (unlikely(!page)) {
1293        oo = s->min;
1294        /*
1295         * Allocation may have failed due to fragmentation.
1296         * Try a lower order alloc if possible
1297         */
1298        page = alloc_slab_page(flags, node, oo);
1299
1300        if (page)
1301            stat(s, ORDER_FALLBACK);
1302    }
1303
1304    if (kmemcheck_enabled && page
1305        && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1306        int pages = 1 << oo_order(oo);
1307
1308        kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
1309
1310        /*
1311         * Objects from caches that have a constructor don't get
1312         * cleared when they're allocated, so we need to do it here.
1313         */
1314        if (s->ctor)
1315            kmemcheck_mark_uninitialized_pages(page, pages);
1316        else
1317            kmemcheck_mark_unallocated_pages(page, pages);
1318    }
1319
1320    if (flags & __GFP_WAIT)
1321        local_irq_disable();
1322    if (!page)
1323        return NULL;
1324
1325    page->objects = oo_objects(oo);
1326    mod_zone_page_state(page_zone(page),
1327        (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1328        NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1329        1 << oo_order(oo));
1330
1331    return page;
1332}
1333
1334static void setup_object(struct kmem_cache *s, struct page *page,
1335                void *object)
1336{
1337    setup_object_debug(s, page, object);
1338    if (unlikely(s->ctor))
1339        s->ctor(object);
1340}
1341
1342static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1343{
1344    struct page *page;
1345    void *start;
1346    void *last;
1347    void *p;
1348    int order;
1349
1350    BUG_ON(flags & GFP_SLAB_BUG_MASK);
1351
1352    page = allocate_slab(s,
1353        flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1354    if (!page)
1355        goto out;
1356
1357    order = compound_order(page);
1358    inc_slabs_node(s, page_to_nid(page), page->objects);
1359    memcg_bind_pages(s, order);
1360    page->slab_cache = s;
1361    __SetPageSlab(page);
1362    if (page->pfmemalloc)
1363        SetPageSlabPfmemalloc(page);
1364
1365    start = page_address(page);
1366
1367    if (unlikely(s->flags & SLAB_POISON))
1368        memset(start, POISON_INUSE, PAGE_SIZE << order);
1369
1370    last = start;
1371    for_each_object(p, s, start, page->objects) {
1372        setup_object(s, page, last);
1373        set_freepointer(s, last, p);
1374        last = p;
1375    }
1376    setup_object(s, page, last);
1377    set_freepointer(s, last, NULL);
1378
1379    page->freelist = start;
1380    page->inuse = page->objects;
1381    page->frozen = 1;
1382out:
1383    return page;
1384}
1385
1386static void __free_slab(struct kmem_cache *s, struct page *page)
1387{
1388    int order = compound_order(page);
1389    int pages = 1 << order;
1390
1391    if (kmem_cache_debug(s)) {
1392        void *p;
1393
1394        slab_pad_check(s, page);
1395        for_each_object(p, s, page_address(page),
1396                        page->objects)
1397            check_object(s, page, p, SLUB_RED_INACTIVE);
1398    }
1399
1400    kmemcheck_free_shadow(page, compound_order(page));
1401
1402    mod_zone_page_state(page_zone(page),
1403        (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1404        NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1405        -pages);
1406
1407    __ClearPageSlabPfmemalloc(page);
1408    __ClearPageSlab(page);
1409
1410    memcg_release_pages(s, order);
1411    page_mapcount_reset(page);
1412    if (current->reclaim_state)
1413        current->reclaim_state->reclaimed_slab += pages;
1414    __free_memcg_kmem_pages(page, order);
1415}
1416
1417#define need_reserve_slab_rcu \
1418    (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1419
1420static void rcu_free_slab(struct rcu_head *h)
1421{
1422    struct page *page;
1423
1424    if (need_reserve_slab_rcu)
1425        page = virt_to_head_page(h);
1426    else
1427        page = container_of((struct list_head *)h, struct page, lru);
1428
1429    __free_slab(page->slab_cache, page);
1430}
1431
1432static void free_slab(struct kmem_cache *s, struct page *page)
1433{
1434    if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1435        struct rcu_head *head;
1436
1437        if (need_reserve_slab_rcu) {
1438            int order = compound_order(page);
1439            int offset = (PAGE_SIZE << order) - s->reserved;
1440
1441            VM_BUG_ON(s->reserved != sizeof(*head));
1442            head = page_address(page) + offset;
1443        } else {
1444            /*
1445             * RCU free overloads the RCU head over the LRU
1446             */
1447            head = (void *)&page->lru;
1448        }
1449
1450        call_rcu(head, rcu_free_slab);
1451    } else
1452        __free_slab(s, page);
1453}
1454
1455static void discard_slab(struct kmem_cache *s, struct page *page)
1456{
1457    dec_slabs_node(s, page_to_nid(page), page->objects);
1458    free_slab(s, page);
1459}
1460
1461/*
1462 * Management of partially allocated slabs.
1463 *
1464 * list_lock must be held.
1465 */
1466static inline void add_partial(struct kmem_cache_node *n,
1467                struct page *page, int tail)
1468{
1469    n->nr_partial++;
1470    if (tail == DEACTIVATE_TO_TAIL)
1471        list_add_tail(&page->lru, &n->partial);
1472    else
1473        list_add(&page->lru, &n->partial);
1474}
1475
1476/*
1477 * list_lock must be held.
1478 */
1479static inline void remove_partial(struct kmem_cache_node *n,
1480                    struct page *page)
1481{
1482    list_del(&page->lru);
1483    n->nr_partial--;
1484}
1485
1486/*
1487 * Remove slab from the partial list, freeze it and
1488 * return the pointer to the freelist.
1489 *
1490 * Returns a list of objects or NULL if it fails.
1491 *
1492 * Must hold list_lock since we modify the partial list.
1493 */
1494static inline void *acquire_slab(struct kmem_cache *s,
1495        struct kmem_cache_node *n, struct page *page,
1496        int mode)
1497{
1498    void *freelist;
1499    unsigned long counters;
1500    struct page new;
1501
1502    /*
1503     * Zap the freelist and set the frozen bit.
1504     * The old freelist is the list of objects for the
1505     * per cpu allocation list.
1506     */
1507    freelist = page->freelist;
1508    counters = page->counters;
1509    new.counters = counters;
1510    if (mode) {
1511        new.inuse = page->objects;
1512        new.freelist = NULL;
1513    } else {
1514        new.freelist = freelist;
1515    }
1516
1517    VM_BUG_ON(new.frozen);
1518    new.frozen = 1;
1519
1520    if (!__cmpxchg_double_slab(s, page,
1521            freelist, counters,
1522            new.freelist, new.counters,
1523            "acquire_slab"))
1524        return NULL;
1525
1526    remove_partial(n, page);
1527    WARN_ON(!freelist);
1528    return freelist;
1529}
1530
1531static int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1532static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1533
1534/*
1535 * Try to allocate a partial slab from a specific node.
1536 */
1537static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1538                struct kmem_cache_cpu *c, gfp_t flags)
1539{
1540    struct page *page, *page2;
1541    void *object = NULL;
1542
1543    /*
1544     * Racy check. If we mistakenly see no partial slabs then we
1545     * just allocate an empty slab. If we mistakenly try to get a
1546     * partial slab and there is none available then get_partials()
1547     * will return NULL.
1548     */
1549    if (!n || !n->nr_partial)
1550        return NULL;
1551
1552    spin_lock(&n->list_lock);
1553    list_for_each_entry_safe(page, page2, &n->partial, lru) {
1554        void *t;
1555        int available;
1556
1557        if (!pfmemalloc_match(page, flags))
1558            continue;
1559
1560        t = acquire_slab(s, n, page, object == NULL);
1561        if (!t)
1562            break;
1563
1564        if (!object) {
1565            c->page = page;
1566            stat(s, ALLOC_FROM_PARTIAL);
1567            object = t;
1568            available = page->objects - page->inuse;
1569        } else {
1570            available = put_cpu_partial(s, page, 0);
1571            stat(s, CPU_PARTIAL_NODE);
1572        }
1573        if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
1574            break;
1575
1576    }
1577    spin_unlock(&n->list_lock);
1578    return object;
1579}
1580
1581/*
1582 * Get a page from somewhere. Search in increasing NUMA distances.
1583 */
1584static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1585        struct kmem_cache_cpu *c)
1586{
1587#ifdef CONFIG_NUMA
1588    struct zonelist *zonelist;
1589    struct zoneref *z;
1590    struct zone *zone;
1591    enum zone_type high_zoneidx = gfp_zone(flags);
1592    void *object;
1593    unsigned int cpuset_mems_cookie;
1594
1595    /*
1596     * The defrag ratio allows a configuration of the tradeoffs between
1597     * inter node defragmentation and node local allocations. A lower
1598     * defrag_ratio increases the tendency to do local allocations
1599     * instead of attempting to obtain partial slabs from other nodes.
1600     *
1601     * If the defrag_ratio is set to 0 then kmalloc() always
1602     * returns node local objects. If the ratio is higher then kmalloc()
1603     * may return off node objects because partial slabs are obtained
1604     * from other nodes and filled up.
1605     *
1606     * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1607     * defrag_ratio = 1000) then every (well almost) allocation will
1608     * first attempt to defrag slab caches on other nodes. This means
1609     * scanning over all nodes to look for partial slabs which may be
1610     * expensive if we do it every time we are trying to find a slab
1611     * with available objects.
1612     */
1613    if (!s->remote_node_defrag_ratio ||
1614            get_cycles() % 1024 > s->remote_node_defrag_ratio)
1615        return NULL;
1616
1617    do {
1618        cpuset_mems_cookie = get_mems_allowed();
1619        zonelist = node_zonelist(slab_node(), flags);
1620        for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1621            struct kmem_cache_node *n;
1622
1623            n = get_node(s, zone_to_nid(zone));
1624
1625            if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1626                    n->nr_partial > s->min_partial) {
1627                object = get_partial_node(s, n, c, flags);
1628                if (object) {
1629                    /*
1630                     * Return the object even if
1631                     * put_mems_allowed indicated that
1632                     * the cpuset mems_allowed was
1633                     * updated in parallel. It's a
1634                     * harmless race between the alloc
1635                     * and the cpuset update.
1636                     */
1637                    put_mems_allowed(cpuset_mems_cookie);
1638                    return object;
1639                }
1640            }
1641        }
1642    } while (!put_mems_allowed(cpuset_mems_cookie));
1643#endif
1644    return NULL;
1645}
1646
1647/*
1648 * Get a partial page, lock it and return it.
1649 */
1650static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1651        struct kmem_cache_cpu *c)
1652{
1653    void *object;
1654    int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
1655
1656    object = get_partial_node(s, get_node(s, searchnode), c, flags);
1657    if (object || node != NUMA_NO_NODE)
1658        return object;
1659
1660    return get_any_partial(s, flags, c);
1661}
1662
1663#ifdef CONFIG_PREEMPT
1664/*
1665 * Calculate the next globally unique transaction for disambiguiation
1666 * during cmpxchg. The transactions start with the cpu number and are then
1667 * incremented by CONFIG_NR_CPUS.
1668 */
1669#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1670#else
1671/*
1672 * No preemption supported therefore also no need to check for
1673 * different cpus.
1674 */
1675#define TID_STEP 1
1676#endif
1677
1678static inline unsigned long next_tid(unsigned long tid)
1679{
1680    return tid + TID_STEP;
1681}
1682
1683static inline unsigned int tid_to_cpu(unsigned long tid)
1684{
1685    return tid % TID_STEP;
1686}
1687
1688static inline unsigned long tid_to_event(unsigned long tid)
1689{
1690    return tid / TID_STEP;
1691}
1692
1693static inline unsigned int init_tid(int cpu)
1694{
1695    return cpu;
1696}
1697
1698static inline void note_cmpxchg_failure(const char *n,
1699        const struct kmem_cache *s, unsigned long tid)
1700{
1701#ifdef SLUB_DEBUG_CMPXCHG
1702    unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1703
1704    printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
1705
1706#ifdef CONFIG_PREEMPT
1707    if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1708        printk("due to cpu change %d -> %d\n",
1709            tid_to_cpu(tid), tid_to_cpu(actual_tid));
1710    else
1711#endif
1712    if (tid_to_event(tid) != tid_to_event(actual_tid))
1713        printk("due to cpu running other code. Event %ld->%ld\n",
1714            tid_to_event(tid), tid_to_event(actual_tid));
1715    else
1716        printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1717            actual_tid, tid, next_tid(tid));
1718#endif
1719    stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1720}
1721
1722static void init_kmem_cache_cpus(struct kmem_cache *s)
1723{
1724    int cpu;
1725
1726    for_each_possible_cpu(cpu)
1727        per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1728}
1729
1730/*
1731 * Remove the cpu slab
1732 */
1733static void deactivate_slab(struct kmem_cache *s, struct page *page, void *freelist)
1734{
1735    enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1736    struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1737    int lock = 0;
1738    enum slab_modes l = M_NONE, m = M_NONE;
1739    void *nextfree;
1740    int tail = DEACTIVATE_TO_HEAD;
1741    struct page new;
1742    struct page old;
1743
1744    if (page->freelist) {
1745        stat(s, DEACTIVATE_REMOTE_FREES);
1746        tail = DEACTIVATE_TO_TAIL;
1747    }
1748
1749    /*
1750     * Stage one: Free all available per cpu objects back
1751     * to the page freelist while it is still frozen. Leave the
1752     * last one.
1753     *
1754     * There is no need to take the list->lock because the page
1755     * is still frozen.
1756     */
1757    while (freelist && (nextfree = get_freepointer(s, freelist))) {
1758        void *prior;
1759        unsigned long counters;
1760
1761        do {
1762            prior = page->freelist;
1763            counters = page->counters;
1764            set_freepointer(s, freelist, prior);
1765            new.counters = counters;
1766            new.inuse--;
1767            VM_BUG_ON(!new.frozen);
1768
1769        } while (!__cmpxchg_double_slab(s, page,
1770            prior, counters,
1771            freelist, new.counters,
1772            "drain percpu freelist"));
1773
1774        freelist = nextfree;
1775    }
1776
1777    /*
1778     * Stage two: Ensure that the page is unfrozen while the
1779     * list presence reflects the actual number of objects
1780     * during unfreeze.
1781     *
1782     * We setup the list membership and then perform a cmpxchg
1783     * with the count. If there is a mismatch then the page
1784     * is not unfrozen but the page is on the wrong list.
1785     *
1786     * Then we restart the process which may have to remove
1787     * the page from the list that we just put it on again
1788     * because the number of objects in the slab may have
1789     * changed.
1790     */
1791redo:
1792
1793    old.freelist = page->freelist;
1794    old.counters = page->counters;
1795    VM_BUG_ON(!old.frozen);
1796
1797    /* Determine target state of the slab */
1798    new.counters = old.counters;
1799    if (freelist) {
1800        new.inuse--;
1801        set_freepointer(s, freelist, old.freelist);
1802        new.freelist = freelist;
1803    } else
1804        new.freelist = old.freelist;
1805
1806    new.frozen = 0;
1807
1808    if (!new.inuse && n->nr_partial > s->min_partial)
1809        m = M_FREE;
1810    else if (new.freelist) {
1811        m = M_PARTIAL;
1812        if (!lock) {
1813            lock = 1;
1814            /*
1815             * Taking the spinlock removes the possiblity
1816             * that acquire_slab() will see a slab page that
1817             * is frozen
1818             */
1819            spin_lock(&n->list_lock);
1820        }
1821    } else {
1822        m = M_FULL;
1823        if (kmem_cache_debug(s) && !lock) {
1824            lock = 1;
1825            /*
1826             * This also ensures that the scanning of full
1827             * slabs from diagnostic functions will not see
1828             * any frozen slabs.
1829             */
1830            spin_lock(&n->list_lock);
1831        }
1832    }
1833
1834    if (l != m) {
1835
1836        if (l == M_PARTIAL)
1837
1838            remove_partial(n, page);
1839
1840        else if (l == M_FULL)
1841
1842            remove_full(s, page);
1843
1844        if (m == M_PARTIAL) {
1845
1846            add_partial(n, page, tail);
1847            stat(s, tail);
1848
1849        } else if (m == M_FULL) {
1850
1851            stat(s, DEACTIVATE_FULL);
1852            add_full(s, n, page);
1853
1854        }
1855    }
1856
1857    l = m;
1858    if (!__cmpxchg_double_slab(s, page,
1859                old.freelist, old.counters,
1860                new.freelist, new.counters,
1861                "unfreezing slab"))
1862        goto redo;
1863
1864    if (lock)
1865        spin_unlock(&n->list_lock);
1866
1867    if (m == M_FREE) {
1868        stat(s, DEACTIVATE_EMPTY);
1869        discard_slab(s, page);
1870        stat(s, FREE_SLAB);
1871    }
1872}
1873
1874/*
1875 * Unfreeze all the cpu partial slabs.
1876 *
1877 * This function must be called with interrupts disabled
1878 * for the cpu using c (or some other guarantee must be there
1879 * to guarantee no concurrent accesses).
1880 */
1881static void unfreeze_partials(struct kmem_cache *s,
1882        struct kmem_cache_cpu *c)
1883{
1884    struct kmem_cache_node *n = NULL, *n2 = NULL;
1885    struct page *page, *discard_page = NULL;
1886
1887    while ((page = c->partial)) {
1888        struct page new;
1889        struct page old;
1890
1891        c->partial = page->next;
1892
1893        n2 = get_node(s, page_to_nid(page));
1894        if (n != n2) {
1895            if (n)
1896                spin_unlock(&n->list_lock);
1897
1898            n = n2;
1899            spin_lock(&n->list_lock);
1900        }
1901
1902        do {
1903
1904            old.freelist = page->freelist;
1905            old.counters = page->counters;
1906            VM_BUG_ON(!old.frozen);
1907
1908            new.counters = old.counters;
1909            new.freelist = old.freelist;
1910
1911            new.frozen = 0;
1912
1913        } while (!__cmpxchg_double_slab(s, page,
1914                old.freelist, old.counters,
1915                new.freelist, new.counters,
1916                "unfreezing slab"));
1917
1918        if (unlikely(!new.inuse && n->nr_partial > s->min_partial)) {
1919            page->next = discard_page;
1920            discard_page = page;
1921        } else {
1922            add_partial(n, page, DEACTIVATE_TO_TAIL);
1923            stat(s, FREE_ADD_PARTIAL);
1924        }
1925    }
1926
1927    if (n)
1928        spin_unlock(&n->list_lock);
1929
1930    while (discard_page) {
1931        page = discard_page;
1932        discard_page = discard_page->next;
1933
1934        stat(s, DEACTIVATE_EMPTY);
1935        discard_slab(s, page);
1936        stat(s, FREE_SLAB);
1937    }
1938}
1939
1940/*
1941 * Put a page that was just frozen (in __slab_free) into a partial page
1942 * slot if available. This is done without interrupts disabled and without
1943 * preemption disabled. The cmpxchg is racy and may put the partial page
1944 * onto a random cpus partial slot.
1945 *
1946 * If we did not find a slot then simply move all the partials to the
1947 * per node partial list.
1948 */
1949static int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
1950{
1951    struct page *oldpage;
1952    int pages;
1953    int pobjects;
1954
1955    do {
1956        pages = 0;
1957        pobjects = 0;
1958        oldpage = this_cpu_read(s->cpu_slab->partial);
1959
1960        if (oldpage) {
1961            pobjects = oldpage->pobjects;
1962            pages = oldpage->pages;
1963            if (drain && pobjects > s->cpu_partial) {
1964                unsigned long flags;
1965                /*
1966                 * partial array is full. Move the existing
1967                 * set to the per node partial list.
1968                 */
1969                local_irq_save(flags);
1970                unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
1971                local_irq_restore(flags);
1972                oldpage = NULL;
1973                pobjects = 0;
1974                pages = 0;
1975                stat(s, CPU_PARTIAL_DRAIN);
1976            }
1977        }
1978
1979        pages++;
1980        pobjects += page->objects - page->inuse;
1981
1982        page->pages = pages;
1983        page->pobjects = pobjects;
1984        page->next = oldpage;
1985
1986    } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
1987    return pobjects;
1988}
1989
1990static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
1991{
1992    stat(s, CPUSLAB_FLUSH);
1993    deactivate_slab(s, c->page, c->freelist);
1994
1995    c->tid = next_tid(c->tid);
1996    c->page = NULL;
1997    c->freelist = NULL;
1998}
1999
2000/*
2001 * Flush cpu slab.
2002 *
2003 * Called from IPI handler with interrupts disabled.
2004 */
2005static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2006{
2007    struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2008
2009    if (likely(c)) {
2010        if (c->page)
2011            flush_slab(s, c);
2012
2013        unfreeze_partials(s, c);
2014    }
2015}
2016
2017static void flush_cpu_slab(void *d)
2018{
2019    struct kmem_cache *s = d;
2020
2021    __flush_cpu_slab(s, smp_processor_id());
2022}
2023
2024static bool has_cpu_slab(int cpu, void *info)
2025{
2026    struct kmem_cache *s = info;
2027    struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2028
2029    return c->page || c->partial;
2030}
2031
2032static void flush_all(struct kmem_cache *s)
2033{
2034    on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2035}
2036
2037/*
2038 * Check if the objects in a per cpu structure fit numa
2039 * locality expectations.
2040 */
2041static inline int node_match(struct page *page, int node)
2042{
2043#ifdef CONFIG_NUMA
2044    if (node != NUMA_NO_NODE && page_to_nid(page) != node)
2045        return 0;
2046#endif
2047    return 1;
2048}
2049
2050static int count_free(struct page *page)
2051{
2052    return page->objects - page->inuse;
2053}
2054
2055static unsigned long count_partial(struct kmem_cache_node *n,
2056                    int (*get_count)(struct page *))
2057{
2058    unsigned long flags;
2059    unsigned long x = 0;
2060    struct page *page;
2061
2062    spin_lock_irqsave(&n->list_lock, flags);
2063    list_for_each_entry(page, &n->partial, lru)
2064        x += get_count(page);
2065    spin_unlock_irqrestore(&n->list_lock, flags);
2066    return x;
2067}
2068
2069static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2070{
2071#ifdef CONFIG_SLUB_DEBUG
2072    return atomic_long_read(&n->total_objects);
2073#else
2074    return 0;
2075#endif
2076}
2077
2078static noinline void
2079slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2080{
2081    int node;
2082
2083    printk(KERN_WARNING
2084        "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2085        nid, gfpflags);
2086    printk(KERN_WARNING " cache: %s, object size: %d, buffer size: %d, "
2087        "default order: %d, min order: %d\n", s->name, s->object_size,
2088        s->size, oo_order(s->oo), oo_order(s->min));
2089
2090    if (oo_order(s->min) > get_order(s->object_size))
2091        printk(KERN_WARNING " %s debugging increased min order, use "
2092               "slub_debug=O to disable.\n", s->name);
2093
2094    for_each_online_node(node) {
2095        struct kmem_cache_node *n = get_node(s, node);
2096        unsigned long nr_slabs;
2097        unsigned long nr_objs;
2098        unsigned long nr_free;
2099
2100        if (!n)
2101            continue;
2102
2103        nr_free = count_partial(n, count_free);
2104        nr_slabs = node_nr_slabs(n);
2105        nr_objs = node_nr_objs(n);
2106
2107        printk(KERN_WARNING
2108            " node %d: slabs: %ld, objs: %ld, free: %ld\n",
2109            node, nr_slabs, nr_objs, nr_free);
2110    }
2111}
2112
2113static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2114            int node, struct kmem_cache_cpu **pc)
2115{
2116    void *freelist;
2117    struct kmem_cache_cpu *c = *pc;
2118    struct page *page;
2119
2120    freelist = get_partial(s, flags, node, c);
2121
2122    if (freelist)
2123        return freelist;
2124
2125    page = new_slab(s, flags, node);
2126    if (page) {
2127        c = __this_cpu_ptr(s->cpu_slab);
2128        if (c->page)
2129            flush_slab(s, c);
2130
2131        /*
2132         * No other reference to the page yet so we can
2133         * muck around with it freely without cmpxchg
2134         */
2135        freelist = page->freelist;
2136        page->freelist = NULL;
2137
2138        stat(s, ALLOC_SLAB);
2139        c->page = page;
2140        *pc = c;
2141    } else
2142        freelist = NULL;
2143
2144    return freelist;
2145}
2146
2147static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2148{
2149    if (unlikely(PageSlabPfmemalloc(page)))
2150        return gfp_pfmemalloc_allowed(gfpflags);
2151
2152    return true;
2153}
2154
2155/*
2156 * Check the page->freelist of a page and either transfer the freelist to the per cpu freelist
2157 * or deactivate the page.
2158 *
2159 * The page is still frozen if the return value is not NULL.
2160 *
2161 * If this function returns NULL then the page has been unfrozen.
2162 *
2163 * This function must be called with interrupt disabled.
2164 */
2165static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2166{
2167    struct page new;
2168    unsigned long counters;
2169    void *freelist;
2170
2171    do {
2172        freelist = page->freelist;
2173        counters = page->counters;
2174
2175        new.counters = counters;
2176        VM_BUG_ON(!new.frozen);
2177
2178        new.inuse = page->objects;
2179        new.frozen = freelist != NULL;
2180
2181    } while (!__cmpxchg_double_slab(s, page,
2182        freelist, counters,
2183        NULL, new.counters,
2184        "get_freelist"));
2185
2186    return freelist;
2187}
2188
2189/*
2190 * Slow path. The lockless freelist is empty or we need to perform
2191 * debugging duties.
2192 *
2193 * Processing is still very fast if new objects have been freed to the
2194 * regular freelist. In that case we simply take over the regular freelist
2195 * as the lockless freelist and zap the regular freelist.
2196 *
2197 * If that is not working then we fall back to the partial lists. We take the
2198 * first element of the freelist as the object to allocate now and move the
2199 * rest of the freelist to the lockless freelist.
2200 *
2201 * And if we were unable to get a new slab from the partial slab lists then
2202 * we need to allocate a new slab. This is the slowest path since it involves
2203 * a call to the page allocator and the setup of a new slab.
2204 */
2205static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2206              unsigned long addr, struct kmem_cache_cpu *c)
2207{
2208    void *freelist;
2209    struct page *page;
2210    unsigned long flags;
2211
2212    local_irq_save(flags);
2213#ifdef CONFIG_PREEMPT
2214    /*
2215     * We may have been preempted and rescheduled on a different
2216     * cpu before disabling interrupts. Need to reload cpu area
2217     * pointer.
2218     */
2219    c = this_cpu_ptr(s->cpu_slab);
2220#endif
2221
2222    page = c->page;
2223    if (!page)
2224        goto new_slab;
2225redo:
2226
2227    if (unlikely(!node_match(page, node))) {
2228        stat(s, ALLOC_NODE_MISMATCH);
2229        deactivate_slab(s, page, c->freelist);
2230        c->page = NULL;
2231        c->freelist = NULL;
2232        goto new_slab;
2233    }
2234
2235    /*
2236     * By rights, we should be searching for a slab page that was
2237     * PFMEMALLOC but right now, we are losing the pfmemalloc
2238     * information when the page leaves the per-cpu allocator
2239     */
2240    if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2241        deactivate_slab(s, page, c->freelist);
2242        c->page = NULL;
2243        c->freelist = NULL;
2244        goto new_slab;
2245    }
2246
2247    /* must check again c->freelist in case of cpu migration or IRQ */
2248    freelist = c->freelist;
2249    if (freelist)
2250        goto load_freelist;
2251
2252    stat(s, ALLOC_SLOWPATH);
2253
2254    freelist = get_freelist(s, page);
2255
2256    if (!freelist) {
2257        c->page = NULL;
2258        stat(s, DEACTIVATE_BYPASS);
2259        goto new_slab;
2260    }
2261
2262    stat(s, ALLOC_REFILL);
2263
2264load_freelist:
2265    /*
2266     * freelist is pointing to the list of objects to be used.
2267     * page is pointing to the page from which the objects are obtained.
2268     * That page must be frozen for per cpu allocations to work.
2269     */
2270    VM_BUG_ON(!c->page->frozen);
2271    c->freelist = get_freepointer(s, freelist);
2272    c->tid = next_tid(c->tid);
2273    local_irq_restore(flags);
2274    return freelist;
2275
2276new_slab:
2277
2278    if (c->partial) {
2279        page = c->page = c->partial;
2280        c->partial = page->next;
2281        stat(s, CPU_PARTIAL_ALLOC);
2282        c->freelist = NULL;
2283        goto redo;
2284    }
2285
2286    freelist = new_slab_objects(s, gfpflags, node, &c);
2287
2288    if (unlikely(!freelist)) {
2289        if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
2290            slab_out_of_memory(s, gfpflags, node);
2291
2292        local_irq_restore(flags);
2293        return NULL;
2294    }
2295
2296    page = c->page;
2297    if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2298        goto load_freelist;
2299
2300    /* Only entered in the debug case */
2301    if (kmem_cache_debug(s) && !alloc_debug_processing(s, page, freelist, addr))
2302        goto new_slab; /* Slab failed checks. Next slab needed */
2303
2304    deactivate_slab(s, page, get_freepointer(s, freelist));
2305    c->page = NULL;
2306    c->freelist = NULL;
2307    local_irq_restore(flags);
2308    return freelist;
2309}
2310
2311/*
2312 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2313 * have the fastpath folded into their functions. So no function call
2314 * overhead for requests that can be satisfied on the fastpath.
2315 *
2316 * The fastpath works by first checking if the lockless freelist can be used.
2317 * If not then __slab_alloc is called for slow processing.
2318 *
2319 * Otherwise we can simply pick the next object from the lockless free list.
2320 */
2321static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2322        gfp_t gfpflags, int node, unsigned long addr)
2323{
2324    void **object;
2325    struct kmem_cache_cpu *c;
2326    struct page *page;
2327    unsigned long tid;
2328
2329    if (slab_pre_alloc_hook(s, gfpflags))
2330        return NULL;
2331
2332    s = memcg_kmem_get_cache(s, gfpflags);
2333redo:
2334
2335    /*
2336     * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2337     * enabled. We may switch back and forth between cpus while
2338     * reading from one cpu area. That does not matter as long
2339     * as we end up on the original cpu again when doing the cmpxchg.
2340     */
2341    c = __this_cpu_ptr(s->cpu_slab);
2342
2343    /*
2344     * The transaction ids are globally unique per cpu and per operation on
2345     * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2346     * occurs on the right processor and that there was no operation on the
2347     * linked list in between.
2348     */
2349    tid = c->tid;
2350    barrier();
2351
2352    object = c->freelist;
2353    page = c->page;
2354    if (unlikely(!object || !node_match(page, node)))
2355        object = __slab_alloc(s, gfpflags, node, addr, c);
2356
2357    else {
2358        void *next_object = get_freepointer_safe(s, object);
2359
2360        /*
2361         * The cmpxchg will only match if there was no additional
2362         * operation and if we are on the right processor.
2363         *
2364         * The cmpxchg does the following atomically (without lock semantics!)
2365         * 1. Relocate first pointer to the current per cpu area.
2366         * 2. Verify that tid and freelist have not been changed
2367         * 3. If they were not changed replace tid and freelist
2368         *
2369         * Since this is without lock semantics the protection is only against
2370         * code executing on this cpu *not* from access by other cpus.
2371         */
2372        if (unlikely(!this_cpu_cmpxchg_double(
2373                s->cpu_slab->freelist, s->cpu_slab->tid,
2374                object, tid,
2375                next_object, next_tid(tid)))) {
2376
2377            note_cmpxchg_failure("slab_alloc", s, tid);
2378            goto redo;
2379        }
2380        prefetch_freepointer(s, next_object);
2381        stat(s, ALLOC_FASTPATH);
2382    }
2383
2384    if (unlikely(gfpflags & __GFP_ZERO) && object)
2385        memset(object, 0, s->object_size);
2386
2387    slab_post_alloc_hook(s, gfpflags, object);
2388
2389    return object;
2390}
2391
2392static __always_inline void *slab_alloc(struct kmem_cache *s,
2393        gfp_t gfpflags, unsigned long addr)
2394{
2395    return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2396}
2397
2398void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2399{
2400    void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2401
2402    trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size, s->size, gfpflags);
2403
2404    return ret;
2405}
2406EXPORT_SYMBOL(kmem_cache_alloc);
2407
2408#ifdef CONFIG_TRACING
2409void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2410{
2411    void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2412    trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2413    return ret;
2414}
2415EXPORT_SYMBOL(kmem_cache_alloc_trace);
2416
2417void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
2418{
2419    void *ret = kmalloc_order(size, flags, order);
2420    trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
2421    return ret;
2422}
2423EXPORT_SYMBOL(kmalloc_order_trace);
2424#endif
2425
2426#ifdef CONFIG_NUMA
2427void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2428{
2429    void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2430
2431    trace_kmem_cache_alloc_node(_RET_IP_, ret,
2432                    s->object_size, s->size, gfpflags, node);
2433
2434    return ret;
2435}
2436EXPORT_SYMBOL(kmem_cache_alloc_node);
2437
2438#ifdef CONFIG_TRACING
2439void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2440                    gfp_t gfpflags,
2441                    int node, size_t size)
2442{
2443    void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2444
2445    trace_kmalloc_node(_RET_IP_, ret,
2446               size, s->size, gfpflags, node);
2447    return ret;
2448}
2449EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2450#endif
2451#endif
2452
2453/*
2454 * Slow patch handling. This may still be called frequently since objects
2455 * have a longer lifetime than the cpu slabs in most processing loads.
2456 *
2457 * So we still attempt to reduce cache line usage. Just take the slab
2458 * lock and free the item. If there is no additional partial page
2459 * handling required then we can return immediately.
2460 */
2461static void __slab_free(struct kmem_cache *s, struct page *page,
2462            void *x, unsigned long addr)
2463{
2464    void *prior;
2465    void **object = (void *)x;
2466    int was_frozen;
2467    struct page new;
2468    unsigned long counters;
2469    struct kmem_cache_node *n = NULL;
2470    unsigned long uninitialized_var(flags);
2471
2472    stat(s, FREE_SLOWPATH);
2473
2474    if (kmem_cache_debug(s) &&
2475        !(n = free_debug_processing(s, page, x, addr, &flags)))
2476        return;
2477
2478    do {
2479        if (unlikely(n)) {
2480            spin_unlock_irqrestore(&n->list_lock, flags);
2481            n = NULL;
2482        }
2483        prior = page->freelist;
2484        counters = page->counters;
2485        set_freepointer(s, object, prior);
2486        new.counters = counters;
2487        was_frozen = new.frozen;
2488        new.inuse--;
2489        if ((!new.inuse || !prior) && !was_frozen) {
2490
2491            if (!kmem_cache_debug(s) && !prior)
2492
2493                /*
2494                 * Slab was on no list before and will be partially empty
2495                 * We can defer the list move and instead freeze it.
2496                 */
2497                new.frozen = 1;
2498
2499            else { /* Needs to be taken off a list */
2500
2501                            n = get_node(s, page_to_nid(page));
2502                /*
2503                 * Speculatively acquire the list_lock.
2504                 * If the cmpxchg does not succeed then we may
2505                 * drop the list_lock without any processing.
2506                 *
2507                 * Otherwise the list_lock will synchronize with
2508                 * other processors updating the list of slabs.
2509                 */
2510                spin_lock_irqsave(&n->list_lock, flags);
2511
2512            }
2513        }
2514
2515    } while (!cmpxchg_double_slab(s, page,
2516        prior, counters,
2517        object, new.counters,
2518        "__slab_free"));
2519
2520    if (likely(!n)) {
2521
2522        /*
2523         * If we just froze the page then put it onto the
2524         * per cpu partial list.
2525         */
2526        if (new.frozen && !was_frozen) {
2527            put_cpu_partial(s, page, 1);
2528            stat(s, CPU_PARTIAL_FREE);
2529        }
2530        /*
2531         * The list lock was not taken therefore no list
2532         * activity can be necessary.
2533         */
2534                if (was_frozen)
2535                        stat(s, FREE_FROZEN);
2536                return;
2537        }
2538
2539    if (unlikely(!new.inuse && n->nr_partial > s->min_partial))
2540        goto slab_empty;
2541
2542    /*
2543     * Objects left in the slab. If it was not on the partial list before
2544     * then add it.
2545     */
2546    if (kmem_cache_debug(s) && unlikely(!prior)) {
2547        remove_full(s, page);
2548        add_partial(n, page, DEACTIVATE_TO_TAIL);
2549        stat(s, FREE_ADD_PARTIAL);
2550    }
2551    spin_unlock_irqrestore(&n->list_lock, flags);
2552    return;
2553
2554slab_empty:
2555    if (prior) {
2556        /*
2557         * Slab on the partial list.
2558         */
2559        remove_partial(n, page);
2560        stat(s, FREE_REMOVE_PARTIAL);
2561    } else
2562        /* Slab must be on the full list */
2563        remove_full(s, page);
2564
2565    spin_unlock_irqrestore(&n->list_lock, flags);
2566    stat(s, FREE_SLAB);
2567    discard_slab(s, page);
2568}
2569
2570/*
2571 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2572 * can perform fastpath freeing without additional function calls.
2573 *
2574 * The fastpath is only possible if we are freeing to the current cpu slab
2575 * of this processor. This typically the case if we have just allocated
2576 * the item before.
2577 *
2578 * If fastpath is not possible then fall back to __slab_free where we deal
2579 * with all sorts of special processing.
2580 */
2581static __always_inline void slab_free(struct kmem_cache *s,
2582            struct page *page, void *x, unsigned long addr)
2583{
2584    void **object = (void *)x;
2585    struct kmem_cache_cpu *c;
2586    unsigned long tid;
2587
2588    slab_free_hook(s, x);
2589
2590redo:
2591    /*
2592     * Determine the currently cpus per cpu slab.
2593     * The cpu may change afterward. However that does not matter since
2594     * data is retrieved via this pointer. If we are on the same cpu
2595     * during the cmpxchg then the free will succedd.
2596     */
2597    c = __this_cpu_ptr(s->cpu_slab);
2598
2599    tid = c->tid;
2600    barrier();
2601
2602    if (likely(page == c->page)) {
2603        set_freepointer(s, object, c->freelist);
2604
2605        if (unlikely(!this_cpu_cmpxchg_double(
2606                s->cpu_slab->freelist, s->cpu_slab->tid,
2607                c->freelist, tid,
2608                object, next_tid(tid)))) {
2609
2610            note_cmpxchg_failure("slab_free", s, tid);
2611            goto redo;
2612        }
2613        stat(s, FREE_FASTPATH);
2614    } else
2615        __slab_free(s, page, x, addr);
2616
2617}
2618
2619void kmem_cache_free(struct kmem_cache *s, void *x)
2620{
2621    s = cache_from_obj(s, x);
2622    if (!s)
2623        return;
2624    slab_free(s, virt_to_head_page(x), x, _RET_IP_);
2625    trace_kmem_cache_free(_RET_IP_, x);
2626}
2627EXPORT_SYMBOL(kmem_cache_free);
2628
2629/*
2630 * Object placement in a slab is made very easy because we always start at
2631 * offset 0. If we tune the size of the object to the alignment then we can
2632 * get the required alignment by putting one properly sized object after
2633 * another.
2634 *
2635 * Notice that the allocation order determines the sizes of the per cpu
2636 * caches. Each processor has always one slab available for allocations.
2637 * Increasing the allocation order reduces the number of times that slabs
2638 * must be moved on and off the partial lists and is therefore a factor in
2639 * locking overhead.
2640 */
2641
2642/*
2643 * Mininum / Maximum order of slab pages. This influences locking overhead
2644 * and slab fragmentation. A higher order reduces the number of partial slabs
2645 * and increases the number of allocations possible without having to
2646 * take the list_lock.
2647 */
2648static int slub_min_order;
2649static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
2650static int slub_min_objects;
2651
2652/*
2653 * Merge control. If this is set then no merging of slab caches will occur.
2654 * (Could be removed. This was introduced to pacify the merge skeptics.)
2655 */
2656static int slub_nomerge;
2657
2658/*
2659 * Calculate the order of allocation given an slab object size.
2660 *
2661 * The order of allocation has significant impact on performance and other
2662 * system components. Generally order 0 allocations should be preferred since
2663 * order 0 does not cause fragmentation in the page allocator. Larger objects
2664 * be problematic to put into order 0 slabs because there may be too much
2665 * unused space left. We go to a higher order if more than 1/16th of the slab
2666 * would be wasted.
2667 *
2668 * In order to reach satisfactory performance we must ensure that a minimum
2669 * number of objects is in one slab. Otherwise we may generate too much
2670 * activity on the partial lists which requires taking the list_lock. This is
2671 * less a concern for large slabs though which are rarely used.
2672 *
2673 * slub_max_order specifies the order where we begin to stop considering the
2674 * number of objects in a slab as critical. If we reach slub_max_order then
2675 * we try to keep the page order as low as possible. So we accept more waste
2676 * of space in favor of a small page order.
2677 *
2678 * Higher order allocations also allow the placement of more objects in a
2679 * slab and thereby reduce object handling overhead. If the user has
2680 * requested a higher mininum order then we start with that one instead of
2681 * the smallest order which will fit the object.
2682 */
2683static inline int slab_order(int size, int min_objects,
2684                int max_order, int fract_leftover, int reserved)
2685{
2686    int order;
2687    int rem;
2688    int min_order = slub_min_order;
2689
2690    if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
2691        return get_order(size * MAX_OBJS_PER_PAGE) - 1;
2692
2693    for (order = max(min_order,
2694                fls(min_objects * size - 1) - PAGE_SHIFT);
2695            order <= max_order; order++) {
2696
2697        unsigned long slab_size = PAGE_SIZE << order;
2698
2699        if (slab_size < min_objects * size + reserved)
2700            continue;
2701
2702        rem = (slab_size - reserved) % size;
2703
2704        if (rem <= slab_size / fract_leftover)
2705            break;
2706
2707    }
2708
2709    return order;
2710}
2711
2712static inline int calculate_order(int size, int reserved)
2713{
2714    int order;
2715    int min_objects;
2716    int fraction;
2717    int max_objects;
2718
2719    /*
2720     * Attempt to find best configuration for a slab. This
2721     * works by first attempting to generate a layout with
2722     * the best configuration and backing off gradually.
2723     *
2724     * First we reduce the acceptable waste in a slab. Then
2725     * we reduce the minimum objects required in a slab.
2726     */
2727    min_objects = slub_min_objects;
2728    if (!min_objects)
2729        min_objects = 4 * (fls(nr_cpu_ids) + 1);
2730    max_objects = order_objects(slub_max_order, size, reserved);
2731    min_objects = min(min_objects, max_objects);
2732
2733    while (min_objects > 1) {
2734        fraction = 16;
2735        while (fraction >= 4) {
2736            order = slab_order(size, min_objects,
2737                    slub_max_order, fraction, reserved);
2738            if (order <= slub_max_order)
2739                return order;
2740            fraction /= 2;
2741        }
2742        min_objects--;
2743    }
2744
2745    /*
2746     * We were unable to place multiple objects in a slab. Now
2747     * lets see if we can place a single object there.
2748     */
2749    order = slab_order(size, 1, slub_max_order, 1, reserved);
2750    if (order <= slub_max_order)
2751        return order;
2752
2753    /*
2754     * Doh this slab cannot be placed using slub_max_order.
2755     */
2756    order = slab_order(size, 1, MAX_ORDER, 1, reserved);
2757    if (order < MAX_ORDER)
2758        return order;
2759    return -ENOSYS;
2760}
2761
2762static void
2763init_kmem_cache_node(struct kmem_cache_node *n)
2764{
2765    n->nr_partial = 0;
2766    spin_lock_init(&n->list_lock);
2767    INIT_LIST_HEAD(&n->partial);
2768#ifdef CONFIG_SLUB_DEBUG
2769    atomic_long_set(&n->nr_slabs, 0);
2770    atomic_long_set(&n->total_objects, 0);
2771    INIT_LIST_HEAD(&n->full);
2772#endif
2773}
2774
2775static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
2776{
2777    BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
2778            SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
2779
2780    /*
2781     * Must align to double word boundary for the double cmpxchg
2782     * instructions to work; see __pcpu_double_call_return_bool().
2783     */
2784    s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2785                     2 * sizeof(void *));
2786
2787    if (!s->cpu_slab)
2788        return 0;
2789
2790    init_kmem_cache_cpus(s);
2791
2792    return 1;
2793}
2794
2795static struct kmem_cache *kmem_cache_node;
2796
2797/*
2798 * No kmalloc_node yet so do it by hand. We know that this is the first
2799 * slab on the node for this slabcache. There are no concurrent accesses
2800 * possible.
2801 *
2802 * Note that this function only works on the kmalloc_node_cache
2803 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2804 * memory on a fresh node that has no slab structures yet.
2805 */
2806static void early_kmem_cache_node_alloc(int node)
2807{
2808    struct page *page;
2809    struct kmem_cache_node *n;
2810
2811    BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
2812
2813    page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
2814
2815    BUG_ON(!page);
2816    if (page_to_nid(page) != node) {
2817        printk(KERN_ERR "SLUB: Unable to allocate memory from "
2818                "node %d\n", node);
2819        printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2820                "in order to be able to continue\n");
2821    }
2822
2823    n = page->freelist;
2824    BUG_ON(!n);
2825    page->freelist = get_freepointer(kmem_cache_node, n);
2826    page->inuse = 1;
2827    page->frozen = 0;
2828    kmem_cache_node->node[node] = n;
2829#ifdef CONFIG_SLUB_DEBUG
2830    init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
2831    init_tracking(kmem_cache_node, n);
2832#endif
2833    init_kmem_cache_node(n);
2834    inc_slabs_node(kmem_cache_node, node, page->objects);
2835
2836    add_partial(n, page, DEACTIVATE_TO_HEAD);
2837}
2838
2839static void free_kmem_cache_nodes(struct kmem_cache *s)
2840{
2841    int node;
2842
2843    for_each_node_state(node, N_NORMAL_MEMORY) {
2844        struct kmem_cache_node *n = s->node[node];
2845
2846        if (n)
2847            kmem_cache_free(kmem_cache_node, n);
2848
2849        s->node[node] = NULL;
2850    }
2851}
2852
2853static int init_kmem_cache_nodes(struct kmem_cache *s)
2854{
2855    int node;
2856
2857    for_each_node_state(node, N_NORMAL_MEMORY) {
2858        struct kmem_cache_node *n;
2859
2860        if (slab_state == DOWN) {
2861            early_kmem_cache_node_alloc(node);
2862            continue;
2863        }
2864        n = kmem_cache_alloc_node(kmem_cache_node,
2865                        GFP_KERNEL, node);
2866
2867        if (!n) {
2868            free_kmem_cache_nodes(s);
2869            return 0;
2870        }
2871
2872        s->node[node] = n;
2873        init_kmem_cache_node(n);
2874    }
2875    return 1;
2876}
2877
2878static void set_min_partial(struct kmem_cache *s, unsigned long min)
2879{
2880    if (min < MIN_PARTIAL)
2881        min = MIN_PARTIAL;
2882    else if (min > MAX_PARTIAL)
2883        min = MAX_PARTIAL;
2884    s->min_partial = min;
2885}
2886
2887/*
2888 * calculate_sizes() determines the order and the distribution of data within
2889 * a slab object.
2890 */
2891static int calculate_sizes(struct kmem_cache *s, int forced_order)
2892{
2893    unsigned long flags = s->flags;
2894    unsigned long size = s->object_size;
2895    int order;
2896
2897    /*
2898     * Round up object size to the next word boundary. We can only
2899     * place the free pointer at word boundaries and this determines
2900     * the possible location of the free pointer.
2901     */
2902    size = ALIGN(size, sizeof(void *));
2903
2904#ifdef CONFIG_SLUB_DEBUG
2905    /*
2906     * Determine if we can poison the object itself. If the user of
2907     * the slab may touch the object after free or before allocation
2908     * then we should never poison the object itself.
2909     */
2910    if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2911            !s->ctor)
2912        s->flags |= __OBJECT_POISON;
2913    else
2914        s->flags &= ~__OBJECT_POISON;
2915
2916
2917    /*
2918     * If we are Redzoning then check if there is some space between the
2919     * end of the object and the free pointer. If not then add an
2920     * additional word to have some bytes to store Redzone information.
2921     */
2922    if ((flags & SLAB_RED_ZONE) && size == s->object_size)
2923        size += sizeof(void *);
2924#endif
2925
2926    /*
2927     * With that we have determined the number of bytes in actual use
2928     * by the object. This is the potential offset to the free pointer.
2929     */
2930    s->inuse = size;
2931
2932    if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2933        s->ctor)) {
2934        /*
2935         * Relocate free pointer after the object if it is not
2936         * permitted to overwrite the first word of the object on
2937         * kmem_cache_free.
2938         *
2939         * This is the case if we do RCU, have a constructor or
2940         * destructor or are poisoning the objects.
2941         */
2942        s->offset = size;
2943        size += sizeof(void *);
2944    }
2945
2946#ifdef CONFIG_SLUB_DEBUG
2947    if (flags & SLAB_STORE_USER)
2948        /*
2949         * Need to store information about allocs and frees after
2950         * the object.
2951         */
2952        size += 2 * sizeof(struct track);
2953
2954    if (flags & SLAB_RED_ZONE)
2955        /*
2956         * Add some empty padding so that we can catch
2957         * overwrites from earlier objects rather than let
2958         * tracking information or the free pointer be
2959         * corrupted if a user writes before the start
2960         * of the object.
2961         */
2962        size += sizeof(void *);
2963#endif
2964
2965    /*
2966     * SLUB stores one object immediately after another beginning from
2967     * offset 0. In order to align the objects we have to simply size
2968     * each object to conform to the alignment.
2969     */
2970    size = ALIGN(size, s->align);
2971    s->size = size;
2972    if (forced_order >= 0)
2973        order = forced_order;
2974    else
2975        order = calculate_order(size, s->reserved);
2976
2977    if (order < 0)
2978        return 0;
2979
2980    s->allocflags = 0;
2981    if (order)
2982        s->allocflags |= __GFP_COMP;
2983
2984    if (s->flags & SLAB_CACHE_DMA)
2985        s->allocflags |= SLUB_DMA;
2986
2987    if (s->flags & SLAB_RECLAIM_ACCOUNT)
2988        s->allocflags |= __GFP_RECLAIMABLE;
2989
2990    /*
2991     * Determine the number of objects per slab
2992     */
2993    s->oo = oo_make(order, size, s->reserved);
2994    s->min = oo_make(get_order(size), size, s->reserved);
2995    if (oo_objects(s->oo) > oo_objects(s->max))
2996        s->max = s->oo;
2997
2998    return !!oo_objects(s->oo);
2999}
3000
3001static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
3002{
3003    s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3004    s->reserved = 0;
3005
3006    if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3007        s->reserved = sizeof(struct rcu_head);
3008
3009    if (!calculate_sizes(s, -1))
3010        goto error;
3011    if (disable_higher_order_debug) {
3012        /*
3013         * Disable debugging flags that store metadata if the min slab
3014         * order increased.
3015         */
3016        if (get_order(s->size) > get_order(s->object_size)) {
3017            s->flags &= ~DEBUG_METADATA_FLAGS;
3018            s->offset = 0;
3019            if (!calculate_sizes(s, -1))
3020                goto error;
3021        }
3022    }
3023
3024#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3025    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3026    if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
3027        /* Enable fast mode */
3028        s->flags |= __CMPXCHG_DOUBLE;
3029#endif
3030
3031    /*
3032     * The larger the object size is, the more pages we want on the partial
3033     * list to avoid pounding the page allocator excessively.
3034     */
3035    set_min_partial(s, ilog2(s->size) / 2);
3036
3037    /*
3038     * cpu_partial determined the maximum number of objects kept in the
3039     * per cpu partial lists of a processor.
3040     *
3041     * Per cpu partial lists mainly contain slabs that just have one
3042     * object freed. If they are used for allocation then they can be
3043     * filled up again with minimal effort. The slab will never hit the
3044     * per node partial lists and therefore no locking will be required.
3045     *
3046     * This setting also determines
3047     *
3048     * A) The number of objects from per cpu partial slabs dumped to the
3049     * per node list when we reach the limit.
3050     * B) The number of objects in cpu partial slabs to extract from the
3051     * per node list when we run out of per cpu objects. We only fetch 50%
3052     * to keep some capacity around for frees.
3053     */
3054    if (kmem_cache_debug(s))
3055        s->cpu_partial = 0;
3056    else if (s->size >= PAGE_SIZE)
3057        s->cpu_partial = 2;
3058    else if (s->size >= 1024)
3059        s->cpu_partial = 6;
3060    else if (s->size >= 256)
3061        s->cpu_partial = 13;
3062    else
3063        s->cpu_partial = 30;
3064
3065#ifdef CONFIG_NUMA
3066    s->remote_node_defrag_ratio = 1000;
3067#endif
3068    if (!init_kmem_cache_nodes(s))
3069        goto error;
3070
3071    if (alloc_kmem_cache_cpus(s))
3072        return 0;
3073
3074    free_kmem_cache_nodes(s);
3075error:
3076    if (flags & SLAB_PANIC)
3077        panic("Cannot create slab %s size=%lu realsize=%u "
3078            "order=%u offset=%u flags=%lx\n",
3079            s->name, (unsigned long)s->size, s->size, oo_order(s->oo),
3080            s->offset, flags);
3081    return -EINVAL;
3082}
3083
3084static void list_slab_objects(struct kmem_cache *s, struct page *page,
3085                            const char *text)
3086{
3087#ifdef CONFIG_SLUB_DEBUG
3088    void *addr = page_address(page);
3089    void *p;
3090    unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3091                     sizeof(long), GFP_ATOMIC);
3092    if (!map)
3093        return;
3094    slab_err(s, page, text, s->name);
3095    slab_lock(page);
3096
3097    get_map(s, page, map);
3098    for_each_object(p, s, addr, page->objects) {
3099
3100        if (!test_bit(slab_index(p, s, addr), map)) {
3101            printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
3102                            p, p - addr);
3103            print_tracking(s, p);
3104        }
3105    }
3106    slab_unlock(page);
3107    kfree(map);
3108#endif
3109}
3110
3111/*
3112 * Attempt to free all partial slabs on a node.
3113 * This is called from kmem_cache_close(). We must be the last thread
3114 * using the cache and therefore we do not need to lock anymore.
3115 */
3116static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3117{
3118    struct page *page, *h;
3119
3120    list_for_each_entry_safe(page, h, &n->partial, lru) {
3121        if (!page->inuse) {
3122            remove_partial(n, page);
3123            discard_slab(s, page);
3124        } else {
3125            list_slab_objects(s, page,
3126            "Objects remaining in %s on kmem_cache_close()");
3127        }
3128    }
3129}
3130
3131/*
3132 * Release all resources used by a slab cache.
3133 */
3134static inline int kmem_cache_close(struct kmem_cache *s)
3135{
3136    int node;
3137
3138    flush_all(s);
3139    /* Attempt to free all objects */
3140    for_each_node_state(node, N_NORMAL_MEMORY) {
3141        struct kmem_cache_node *n = get_node(s, node);
3142
3143        free_partial(s, n);
3144        if (n->nr_partial || slabs_node(s, node))
3145            return 1;
3146    }
3147    free_percpu(s->cpu_slab);
3148    free_kmem_cache_nodes(s);
3149    return 0;
3150}
3151
3152int __kmem_cache_shutdown(struct kmem_cache *s)
3153{
3154    int rc = kmem_cache_close(s);
3155
3156    if (!rc) {
3157        /*
3158         * We do the same lock strategy around sysfs_slab_add, see
3159         * __kmem_cache_create. Because this is pretty much the last
3160         * operation we do and the lock will be released shortly after
3161         * that in slab_common.c, we could just move sysfs_slab_remove
3162         * to a later point in common code. We should do that when we
3163         * have a common sysfs framework for all allocators.
3164         */
3165        mutex_unlock(&slab_mutex);
3166        sysfs_slab_remove(s);
3167        mutex_lock(&slab_mutex);
3168    }
3169
3170    return rc;
3171}
3172
3173/********************************************************************
3174 * Kmalloc subsystem
3175 *******************************************************************/
3176
3177struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
3178EXPORT_SYMBOL(kmalloc_caches);
3179
3180#ifdef CONFIG_ZONE_DMA
3181static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
3182#endif
3183
3184static int __init setup_slub_min_order(char *str)
3185{
3186    get_option(&str, &slub_min_order);
3187
3188    return 1;
3189}
3190
3191__setup("slub_min_order=", setup_slub_min_order);
3192
3193static int __init setup_slub_max_order(char *str)
3194{
3195    get_option(&str, &slub_max_order);
3196    slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3197
3198    return 1;
3199}
3200
3201__setup("slub_max_order=", setup_slub_max_order);
3202
3203static int __init setup_slub_min_objects(char *str)
3204{
3205    get_option(&str, &slub_min_objects);
3206
3207    return 1;
3208}
3209
3210__setup("slub_min_objects=", setup_slub_min_objects);
3211
3212static int __init setup_slub_nomerge(char *str)
3213{
3214    slub_nomerge = 1;
3215    return 1;
3216}
3217
3218__setup("slub_nomerge", setup_slub_nomerge);
3219
3220/*
3221 * Conversion table for small slabs sizes / 8 to the index in the
3222 * kmalloc array. This is necessary for slabs < 192 since we have non power
3223 * of two cache sizes there. The size of larger slabs can be determined using
3224 * fls.
3225 */
3226static s8 size_index[24] = {
3227    3, /* 8 */
3228    4, /* 16 */
3229    5, /* 24 */
3230    5, /* 32 */
3231    6, /* 40 */
3232    6, /* 48 */
3233    6, /* 56 */
3234    6, /* 64 */
3235    1, /* 72 */
3236    1, /* 80 */
3237    1, /* 88 */
3238    1, /* 96 */
3239    7, /* 104 */
3240    7, /* 112 */
3241    7, /* 120 */
3242    7, /* 128 */
3243    2, /* 136 */
3244    2, /* 144 */
3245    2, /* 152 */
3246    2, /* 160 */
3247    2, /* 168 */
3248    2, /* 176 */
3249    2, /* 184 */
3250    2 /* 192 */
3251};
3252
3253static inline int size_index_elem(size_t bytes)
3254{
3255    return (bytes - 1) / 8;
3256}
3257
3258static struct kmem_cache *get_slab(size_t size, gfp_t flags)
3259{
3260    int index;
3261
3262    if (size <= 192) {
3263        if (!size)
3264            return ZERO_SIZE_PTR;
3265
3266        index = size_index[size_index_elem(size)];
3267    } else
3268        index = fls(size - 1);
3269
3270#ifdef CONFIG_ZONE_DMA
3271    if (unlikely((flags & SLUB_DMA)))
3272        return kmalloc_dma_caches[index];
3273
3274#endif
3275    return kmalloc_caches[index];
3276}
3277
3278void *__kmalloc(size_t size, gfp_t flags)
3279{
3280    struct kmem_cache *s;
3281    void *ret;
3282
3283    if (unlikely(size > SLUB_MAX_SIZE))
3284        return kmalloc_large(size, flags);
3285
3286    s = get_slab(size, flags);
3287
3288    if (unlikely(ZERO_OR_NULL_PTR(s)))
3289        return s;
3290
3291    ret = slab_alloc(s, flags, _RET_IP_);
3292
3293    trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3294
3295    return ret;
3296}
3297EXPORT_SYMBOL(__kmalloc);
3298
3299#ifdef CONFIG_NUMA
3300static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3301{
3302    struct page *page;
3303    void *ptr = NULL;
3304
3305    flags |= __GFP_COMP | __GFP_NOTRACK | __GFP_KMEMCG;
3306    page = alloc_pages_node(node, flags, get_order(size));
3307    if (page)
3308        ptr = page_address(page);
3309
3310    kmemleak_alloc(ptr, size, 1, flags);
3311    return ptr;
3312}
3313
3314void *__kmalloc_node(size_t size, gfp_t flags, int node)
3315{
3316    struct kmem_cache *s;
3317    void *ret;
3318
3319    if (unlikely(size > SLUB_MAX_SIZE)) {
3320        ret = kmalloc_large_node(size, flags, node);
3321
3322        trace_kmalloc_node(_RET_IP_, ret,
3323                   size, PAGE_SIZE << get_order(size),
3324                   flags, node);
3325
3326        return ret;
3327    }
3328
3329    s = get_slab(size, flags);
3330
3331    if (unlikely(ZERO_OR_NULL_PTR(s)))
3332        return s;
3333
3334    ret = slab_alloc_node(s, flags, node, _RET_IP_);
3335
3336    trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3337
3338    return ret;
3339}
3340EXPORT_SYMBOL(__kmalloc_node);
3341#endif
3342
3343size_t ksize(const void *object)
3344{
3345    struct page *page;
3346
3347    if (unlikely(object == ZERO_SIZE_PTR))
3348        return 0;
3349
3350    page = virt_to_head_page(object);
3351
3352    if (unlikely(!PageSlab(page))) {
3353        WARN_ON(!PageCompound(page));
3354        return PAGE_SIZE << compound_order(page);
3355    }
3356
3357    return slab_ksize(page->slab_cache);
3358}
3359EXPORT_SYMBOL(ksize);
3360
3361#ifdef CONFIG_SLUB_DEBUG
3362bool verify_mem_not_deleted(const void *x)
3363{
3364    struct page *page;
3365    void *object = (void *)x;
3366    unsigned long flags;
3367    bool rv;
3368
3369    if (unlikely(ZERO_OR_NULL_PTR(x)))
3370        return false;
3371
3372    local_irq_save(flags);
3373
3374    page = virt_to_head_page(x);
3375    if (unlikely(!PageSlab(page))) {
3376        /* maybe it was from stack? */
3377        rv = true;
3378        goto out_unlock;
3379    }
3380
3381    slab_lock(page);
3382    if (on_freelist(page->slab_cache, page, object)) {
3383        object_err(page->slab_cache, page, object, "Object is on free-list");
3384        rv = false;
3385    } else {
3386        rv = true;
3387    }
3388    slab_unlock(page);
3389
3390out_unlock:
3391    local_irq_restore(flags);
3392    return rv;
3393}
3394EXPORT_SYMBOL(verify_mem_not_deleted);
3395#endif
3396
3397void kfree(const void *x)
3398{
3399    struct page *page;
3400    void *object = (void *)x;
3401
3402    trace_kfree(_RET_IP_, x);
3403
3404    if (unlikely(ZERO_OR_NULL_PTR(x)))
3405        return;
3406
3407    page = virt_to_head_page(x);
3408    if (unlikely(!PageSlab(page))) {
3409        BUG_ON(!PageCompound(page));
3410        kmemleak_free(x);
3411        __free_memcg_kmem_pages(page, compound_order(page));
3412        return;
3413    }
3414    slab_free(page->slab_cache, page, object, _RET_IP_);
3415}
3416EXPORT_SYMBOL(kfree);
3417
3418/*
3419 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3420 * the remaining slabs by the number of items in use. The slabs with the
3421 * most items in use come first. New allocations will then fill those up
3422 * and thus they can be removed from the partial lists.
3423 *
3424 * The slabs with the least items are placed last. This results in them
3425 * being allocated from last increasing the chance that the last objects
3426 * are freed in them.
3427 */
3428int kmem_cache_shrink(struct kmem_cache *s)
3429{
3430    int node;
3431    int i;
3432    struct kmem_cache_node *n;
3433    struct page *page;
3434    struct page *t;
3435    int objects = oo_objects(s->max);
3436    struct list_head *slabs_by_inuse =
3437        kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
3438    unsigned long flags;
3439
3440    if (!slabs_by_inuse)
3441        return -ENOMEM;
3442
3443    flush_all(s);
3444    for_each_node_state(node, N_NORMAL_MEMORY) {
3445        n = get_node(s, node);
3446
3447        if (!n->nr_partial)
3448            continue;
3449
3450        for (i = 0; i < objects; i++)
3451            INIT_LIST_HEAD(slabs_by_inuse + i);
3452
3453        spin_lock_irqsave(&n->list_lock, flags);
3454
3455        /*
3456         * Build lists indexed by the items in use in each slab.
3457         *
3458         * Note that concurrent frees may occur while we hold the
3459         * list_lock. page->inuse here is the upper limit.
3460         */
3461        list_for_each_entry_safe(page, t, &n->partial, lru) {
3462            list_move(&page->lru, slabs_by_inuse + page->inuse);
3463            if (!page->inuse)
3464                n->nr_partial--;
3465        }
3466
3467        /*
3468         * Rebuild the partial list with the slabs filled up most
3469         * first and the least used slabs at the end.
3470         */
3471        for (i = objects - 1; i > 0; i--)
3472            list_splice(slabs_by_inuse + i, n->partial.prev);
3473
3474        spin_unlock_irqrestore(&n->list_lock, flags);
3475
3476        /* Release empty slabs */
3477        list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
3478            discard_slab(s, page);
3479    }
3480
3481    kfree(slabs_by_inuse);
3482    return 0;
3483}
3484EXPORT_SYMBOL(kmem_cache_shrink);
3485
3486#if defined(CONFIG_MEMORY_HOTPLUG)
3487static int slab_mem_going_offline_callback(void *arg)
3488{
3489    struct kmem_cache *s;
3490
3491    mutex_lock(&slab_mutex);
3492    list_for_each_entry(s, &slab_caches, list)
3493        kmem_cache_shrink(s);
3494    mutex_unlock(&slab_mutex);
3495
3496    return 0;
3497}
3498
3499static void slab_mem_offline_callback(void *arg)
3500{
3501    struct kmem_cache_node *n;
3502    struct kmem_cache *s;
3503    struct memory_notify *marg = arg;
3504    int offline_node;
3505
3506    offline_node = marg->status_change_nid_normal;
3507
3508    /*
3509     * If the node still has available memory. we need kmem_cache_node
3510     * for it yet.
3511     */
3512    if (offline_node < 0)
3513        return;
3514
3515    mutex_lock(&slab_mutex);
3516    list_for_each_entry(s, &slab_caches, list) {
3517        n = get_node(s, offline_node);
3518        if (n) {
3519            /*
3520             * if n->nr_slabs > 0, slabs still exist on the node
3521             * that is going down. We were unable to free them,
3522             * and offline_pages() function shouldn't call this
3523             * callback. So, we must fail.
3524             */
3525            BUG_ON(slabs_node(s, offline_node));
3526
3527            s->node[offline_node] = NULL;
3528            kmem_cache_free(kmem_cache_node, n);
3529        }
3530    }
3531    mutex_unlock(&slab_mutex);
3532}
3533
3534static int slab_mem_going_online_callback(void *arg)
3535{
3536    struct kmem_cache_node *n;
3537    struct kmem_cache *s;
3538    struct memory_notify *marg = arg;
3539    int nid = marg->status_change_nid_normal;
3540    int ret = 0;
3541
3542    /*
3543     * If the node's memory is already available, then kmem_cache_node is
3544     * already created. Nothing to do.
3545     */
3546    if (nid < 0)
3547        return 0;
3548
3549    /*
3550     * We are bringing a node online. No memory is available yet. We must
3551     * allocate a kmem_cache_node structure in order to bring the node
3552     * online.
3553     */
3554    mutex_lock(&slab_mutex);
3555    list_for_each_entry(s, &slab_caches, list) {
3556        /*
3557         * XXX: kmem_cache_alloc_node will fallback to other nodes
3558         * since memory is not yet available from the node that
3559         * is brought up.
3560         */
3561        n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3562        if (!n) {
3563            ret = -ENOMEM;
3564            goto out;
3565        }
3566        init_kmem_cache_node(n);
3567        s->node[nid] = n;
3568    }
3569out:
3570    mutex_unlock(&slab_mutex);
3571    return ret;
3572}
3573
3574static int slab_memory_callback(struct notifier_block *self,
3575                unsigned long action, void *arg)
3576{
3577    int ret = 0;
3578
3579    switch (action) {
3580    case MEM_GOING_ONLINE:
3581        ret = slab_mem_going_online_callback(arg);
3582        break;
3583    case MEM_GOING_OFFLINE:
3584        ret = slab_mem_going_offline_callback(arg);
3585        break;
3586    case MEM_OFFLINE:
3587    case MEM_CANCEL_ONLINE:
3588        slab_mem_offline_callback(arg);
3589        break;
3590    case MEM_ONLINE:
3591    case MEM_CANCEL_OFFLINE:
3592        break;
3593    }
3594    if (ret)
3595        ret = notifier_from_errno(ret);
3596    else
3597        ret = NOTIFY_OK;
3598    return ret;
3599}
3600
3601#endif /* CONFIG_MEMORY_HOTPLUG */
3602
3603/********************************************************************
3604 * Basic setup of slabs
3605 *******************************************************************/
3606
3607/*
3608 * Used for early kmem_cache structures that were allocated using
3609 * the page allocator. Allocate them properly then fix up the pointers
3610 * that may be pointing to the wrong kmem_cache structure.
3611 */
3612
3613static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
3614{
3615    int node;
3616    struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
3617
3618    memcpy(s, static_cache, kmem_cache->object_size);
3619
3620    for_each_node_state(node, N_NORMAL_MEMORY) {
3621        struct kmem_cache_node *n = get_node(s, node);
3622        struct page *p;
3623
3624        if (n) {
3625            list_for_each_entry(p, &n->partial, lru)
3626                p->slab_cache = s;
3627
3628#ifdef CONFIG_SLUB_DEBUG
3629            list_for_each_entry(p, &n->full, lru)
3630                p->slab_cache = s;
3631#endif
3632        }
3633    }
3634    list_add(&s->list, &slab_caches);
3635    return s;
3636}
3637
3638void __init kmem_cache_init(void)
3639{
3640    static __initdata struct kmem_cache boot_kmem_cache,
3641        boot_kmem_cache_node;
3642    int i;
3643    int caches = 2;
3644
3645    if (debug_guardpage_minorder())
3646        slub_max_order = 0;
3647
3648    kmem_cache_node = &boot_kmem_cache_node;
3649    kmem_cache = &boot_kmem_cache;
3650
3651    create_boot_cache(kmem_cache_node, "kmem_cache_node",
3652        sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
3653
3654    hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
3655
3656    /* Able to allocate the per node structures */
3657    slab_state = PARTIAL;
3658
3659    create_boot_cache(kmem_cache, "kmem_cache",
3660            offsetof(struct kmem_cache, node) +
3661                nr_node_ids * sizeof(struct kmem_cache_node *),
3662               SLAB_HWCACHE_ALIGN);
3663
3664    kmem_cache = bootstrap(&boot_kmem_cache);
3665
3666    /*
3667     * Allocate kmem_cache_node properly from the kmem_cache slab.
3668     * kmem_cache_node is separately allocated so no need to
3669     * update any list pointers.
3670     */
3671    kmem_cache_node = bootstrap(&boot_kmem_cache_node);
3672
3673    /* Now we can use the kmem_cache to allocate kmalloc slabs */
3674
3675    /*
3676     * Patch up the size_index table if we have strange large alignment
3677     * requirements for the kmalloc array. This is only the case for
3678     * MIPS it seems. The standard arches will not generate any code here.
3679     *
3680     * Largest permitted alignment is 256 bytes due to the way we
3681     * handle the index determination for the smaller caches.
3682     *
3683     * Make sure that nothing crazy happens if someone starts tinkering
3684     * around with ARCH_KMALLOC_MINALIGN
3685     */
3686    BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
3687        (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
3688
3689    for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
3690        int elem = size_index_elem(i);
3691        if (elem >= ARRAY_SIZE(size_index))
3692            break;
3693        size_index[elem] = KMALLOC_SHIFT_LOW;
3694    }
3695
3696    if (KMALLOC_MIN_SIZE == 64) {
3697        /*
3698         * The 96 byte size cache is not used if the alignment
3699         * is 64 byte.
3700         */
3701        for (i = 64 + 8; i <= 96; i += 8)
3702            size_index[size_index_elem(i)] = 7;
3703    } else if (KMALLOC_MIN_SIZE == 128) {
3704        /*
3705         * The 192 byte sized cache is not used if the alignment
3706         * is 128 byte. Redirect kmalloc to use the 256 byte cache
3707         * instead.
3708         */
3709        for (i = 128 + 8; i <= 192; i += 8)
3710            size_index[size_index_elem(i)] = 8;
3711    }
3712
3713    /* Caches that are not of the two-to-the-power-of size */
3714    if (KMALLOC_MIN_SIZE <= 32) {
3715        kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
3716        caches++;
3717    }
3718
3719    if (KMALLOC_MIN_SIZE <= 64) {
3720        kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
3721        caches++;
3722    }
3723
3724    for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3725        kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
3726        caches++;
3727    }
3728
3729    slab_state = UP;
3730
3731    /* Provide the correct kmalloc names now that the caches are up */
3732    if (KMALLOC_MIN_SIZE <= 32) {
3733        kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT);
3734        BUG_ON(!kmalloc_caches[1]->name);
3735    }
3736
3737    if (KMALLOC_MIN_SIZE <= 64) {
3738        kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT);
3739        BUG_ON(!kmalloc_caches[2]->name);
3740    }
3741
3742    for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3743        char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
3744
3745        BUG_ON(!s);
3746        kmalloc_caches[i]->name = s;
3747    }
3748
3749#ifdef CONFIG_SMP
3750    register_cpu_notifier(&slab_notifier);
3751#endif
3752
3753#ifdef CONFIG_ZONE_DMA
3754    for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
3755        struct kmem_cache *s = kmalloc_caches[i];
3756
3757        if (s && s->size) {
3758            char *name = kasprintf(GFP_NOWAIT,
3759                 "dma-kmalloc-%d", s->object_size);
3760
3761            BUG_ON(!name);
3762            kmalloc_dma_caches[i] = create_kmalloc_cache(name,
3763                s->object_size, SLAB_CACHE_DMA);
3764        }
3765    }
3766#endif
3767    printk(KERN_INFO
3768        "SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3769        " CPUs=%d, Nodes=%d\n",
3770        caches, cache_line_size(),
3771        slub_min_order, slub_max_order, slub_min_objects,
3772        nr_cpu_ids, nr_node_ids);
3773}
3774
3775void __init kmem_cache_init_late(void)
3776{
3777}
3778
3779/*
3780 * Find a mergeable slab cache
3781 */
3782static int slab_unmergeable(struct kmem_cache *s)
3783{
3784    if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3785        return 1;
3786
3787    if (s->ctor)
3788        return 1;
3789
3790    /*
3791     * We may have set a slab to be unmergeable during bootstrap.
3792     */
3793    if (s->refcount < 0)
3794        return 1;
3795
3796    return 0;
3797}
3798
3799static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
3800        size_t align, unsigned long flags, const char *name,
3801        void (*ctor)(void *))
3802{
3803    struct kmem_cache *s;
3804
3805    if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3806        return NULL;
3807
3808    if (ctor)
3809        return NULL;
3810
3811    size = ALIGN(size, sizeof(void *));
3812    align = calculate_alignment(flags, align, size);
3813    size = ALIGN(size, align);
3814    flags = kmem_cache_flags(size, flags, name, NULL);
3815
3816    list_for_each_entry(s, &slab_caches, list) {
3817        if (slab_unmergeable(s))
3818            continue;
3819
3820        if (size > s->size)
3821            continue;
3822
3823        if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3824                continue;
3825        /*
3826         * Check if alignment is compatible.
3827         * Courtesy of Adrian Drzewiecki
3828         */
3829        if ((s->size & ~(align - 1)) != s->size)
3830            continue;
3831
3832        if (s->size - size >= sizeof(void *))
3833            continue;
3834
3835        if (!cache_match_memcg(s, memcg))
3836            continue;
3837
3838        return s;
3839    }
3840    return NULL;
3841}
3842
3843struct kmem_cache *
3844__kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
3845           size_t align, unsigned long flags, void (*ctor)(void *))
3846{
3847    struct kmem_cache *s;
3848
3849    s = find_mergeable(memcg, size, align, flags, name, ctor);
3850    if (s) {
3851        s->refcount++;
3852        /*
3853         * Adjust the object sizes so that we clear
3854         * the complete object on kzalloc.
3855         */
3856        s->object_size = max(s->object_size, (int)size);
3857        s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3858
3859        if (sysfs_slab_alias(s, name)) {
3860            s->refcount--;
3861            s = NULL;
3862        }
3863    }
3864
3865    return s;
3866}
3867
3868int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
3869{
3870    int err;
3871
3872    err = kmem_cache_open(s, flags);
3873    if (err)
3874        return err;
3875
3876    /* Mutex is not taken during early boot */
3877    if (slab_state <= UP)
3878        return 0;
3879
3880    memcg_propagate_slab_attrs(s);
3881    mutex_unlock(&slab_mutex);
3882    err = sysfs_slab_add(s);
3883    mutex_lock(&slab_mutex);
3884
3885    if (err)
3886        kmem_cache_close(s);
3887
3888    return err;
3889}
3890
3891#ifdef CONFIG_SMP
3892/*
3893 * Use the cpu notifier to insure that the cpu slabs are flushed when
3894 * necessary.
3895 */
3896static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3897        unsigned long action, void *hcpu)
3898{
3899    long cpu = (long)hcpu;
3900    struct kmem_cache *s;
3901    unsigned long flags;
3902
3903    switch (action) {
3904    case CPU_UP_CANCELED:
3905    case CPU_UP_CANCELED_FROZEN:
3906    case CPU_DEAD:
3907    case CPU_DEAD_FROZEN:
3908        mutex_lock(&slab_mutex);
3909        list_for_each_entry(s, &slab_caches, list) {
3910            local_irq_save(flags);
3911            __flush_cpu_slab(s, cpu);
3912            local_irq_restore(flags);
3913        }
3914        mutex_unlock(&slab_mutex);
3915        break;
3916    default:
3917        break;
3918    }
3919    return NOTIFY_OK;
3920}
3921
3922static struct notifier_block __cpuinitdata slab_notifier = {
3923    .notifier_call = slab_cpuup_callback
3924};
3925
3926#endif
3927
3928void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
3929{
3930    struct kmem_cache *s;
3931    void *ret;
3932
3933    if (unlikely(size > SLUB_MAX_SIZE))
3934        return kmalloc_large(size, gfpflags);
3935
3936    s = get_slab(size, gfpflags);
3937
3938    if (unlikely(ZERO_OR_NULL_PTR(s)))
3939        return s;
3940
3941    ret = slab_alloc(s, gfpflags, caller);
3942
3943    /* Honor the call site pointer we received. */
3944    trace_kmalloc(caller, ret, size, s->size, gfpflags);
3945
3946    return ret;
3947}
3948
3949#ifdef CONFIG_NUMA
3950void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3951                    int node, unsigned long caller)
3952{
3953    struct kmem_cache *s;
3954    void *ret;
3955
3956    if (unlikely(size > SLUB_MAX_SIZE)) {
3957        ret = kmalloc_large_node(size, gfpflags, node);
3958
3959        trace_kmalloc_node(caller, ret,
3960                   size, PAGE_SIZE << get_order(size),
3961                   gfpflags, node);
3962
3963        return ret;
3964    }
3965
3966    s = get_slab(size, gfpflags);
3967
3968    if (unlikely(ZERO_OR_NULL_PTR(s)))
3969        return s;
3970
3971    ret = slab_alloc_node(s, gfpflags, node, caller);
3972
3973    /* Honor the call site pointer we received. */
3974    trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
3975
3976    return ret;
3977}
3978#endif
3979
3980#ifdef CONFIG_SYSFS
3981static int count_inuse(struct page *page)
3982{
3983    return page->inuse;
3984}
3985
3986static int count_total(struct page *page)
3987{
3988    return page->objects;
3989}
3990#endif
3991
3992#ifdef CONFIG_SLUB_DEBUG
3993static int validate_slab(struct kmem_cache *s, struct page *page,
3994                        unsigned long *map)
3995{
3996    void *p;
3997    void *addr = page_address(page);
3998
3999    if (!check_slab(s, page) ||
4000            !on_freelist(s, page, NULL))
4001        return 0;
4002
4003    /* Now we know that a valid freelist exists */
4004    bitmap_zero(map, page->objects);
4005
4006    get_map(s, page, map);
4007    for_each_object(p, s, addr, page->objects) {
4008        if (test_bit(slab_index(p, s, addr), map))
4009            if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4010                return 0;
4011    }
4012
4013    for_each_object(p, s, addr, page->objects)
4014        if (!test_bit(slab_index(p, s, addr), map))
4015            if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4016                return 0;
4017    return 1;
4018}
4019
4020static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4021                        unsigned long *map)
4022{
4023    slab_lock(page);
4024    validate_slab(s, page, map);
4025    slab_unlock(page);
4026}
4027
4028static int validate_slab_node(struct kmem_cache *s,
4029        struct kmem_cache_node *n, unsigned long *map)
4030{
4031    unsigned long count = 0;
4032    struct page *page;
4033    unsigned long flags;
4034
4035    spin_lock_irqsave(&n->list_lock, flags);
4036
4037    list_for_each_entry(page, &n->partial, lru) {
4038        validate_slab_slab(s, page, map);
4039        count++;
4040    }
4041    if (count != n->nr_partial)
4042        printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
4043            "counter=%ld\n", s->name, count, n->nr_partial);
4044
4045    if (!(s->flags & SLAB_STORE_USER))
4046        goto out;
4047
4048    list_for_each_entry(page, &n->full, lru) {
4049        validate_slab_slab(s, page, map);
4050        count++;
4051    }
4052    if (count != atomic_long_read(&n->nr_slabs))
4053        printk(KERN_ERR "SLUB: %s %ld slabs counted but "
4054            "counter=%ld\n", s->name, count,
4055            atomic_long_read(&n->nr_slabs));
4056
4057out:
4058    spin_unlock_irqrestore(&n->list_lock, flags);
4059    return count;
4060}
4061
4062static long validate_slab_cache(struct kmem_cache *s)
4063{
4064    int node;
4065    unsigned long count = 0;
4066    unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4067                sizeof(unsigned long), GFP_KERNEL);
4068
4069    if (!map)
4070        return -ENOMEM;
4071
4072    flush_all(s);
4073    for_each_node_state(node, N_NORMAL_MEMORY) {
4074        struct kmem_cache_node *n = get_node(s, node);
4075
4076        count += validate_slab_node(s, n, map);
4077    }
4078    kfree(map);
4079    return count;
4080}
4081/*
4082 * Generate lists of code addresses where slabcache objects are allocated
4083 * and freed.
4084 */
4085
4086struct location {
4087    unsigned long count;
4088    unsigned long addr;
4089    long long sum_time;
4090    long min_time;
4091    long max_time;
4092    long min_pid;
4093    long max_pid;
4094    DECLARE_BITMAP(cpus, NR_CPUS);
4095    nodemask_t nodes;
4096};
4097
4098struct loc_track {
4099    unsigned long max;
4100    unsigned long count;
4101    struct location *loc;
4102};
4103
4104static void free_loc_track(struct loc_track *t)
4105{
4106    if (t->max)
4107        free_pages((unsigned long)t->loc,
4108            get_order(sizeof(struct location) * t->max));
4109}
4110
4111static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4112{
4113    struct location *l;
4114    int order;
4115
4116    order = get_order(sizeof(struct location) * max);
4117
4118    l = (void *)__get_free_pages(flags, order);
4119    if (!l)
4120        return 0;
4121
4122    if (t->count) {
4123        memcpy(l, t->loc, sizeof(struct location) * t->count);
4124        free_loc_track(t);
4125    }
4126    t->max = max;
4127    t->loc = l;
4128    return 1;
4129}
4130
4131static int add_location(struct loc_track *t, struct kmem_cache *s,
4132                const struct track *track)
4133{
4134    long start, end, pos;
4135    struct location *l;
4136    unsigned long caddr;
4137    unsigned long age = jiffies - track->when;
4138
4139    start = -1;
4140    end = t->count;
4141
4142    for ( ; ; ) {
4143        pos = start + (end - start + 1) / 2;
4144
4145        /*
4146         * There is nothing at "end". If we end up there
4147         * we need to add something to before end.
4148         */
4149        if (pos == end)
4150            break;
4151
4152        caddr = t->loc[pos].addr;
4153        if (track->addr == caddr) {
4154
4155            l = &t->loc[pos];
4156            l->count++;
4157            if (track->when) {
4158                l->sum_time += age;
4159                if (age < l->min_time)
4160                    l->min_time = age;
4161                if (age > l->max_time)
4162                    l->max_time = age;
4163
4164                if (track->pid < l->min_pid)
4165                    l->min_pid = track->pid;
4166                if (track->pid > l->max_pid)
4167                    l->max_pid = track->pid;
4168
4169                cpumask_set_cpu(track->cpu,
4170                        to_cpumask(l->cpus));
4171            }
4172            node_set(page_to_nid(virt_to_page(track)), l->nodes);
4173            return 1;
4174        }
4175
4176        if (track->addr < caddr)
4177            end = pos;
4178        else
4179            start = pos;
4180    }
4181
4182    /*
4183     * Not found. Insert new tracking element.
4184     */
4185    if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4186        return 0;
4187
4188    l = t->loc + pos;
4189    if (pos < t->count)
4190        memmove(l + 1, l,
4191            (t->count - pos) * sizeof(struct location));
4192    t->count++;
4193    l->count = 1;
4194    l->addr = track->addr;
4195    l->sum_time = age;
4196    l->min_time = age;
4197    l->max_time = age;
4198    l->min_pid = track->pid;
4199    l->max_pid = track->pid;
4200    cpumask_clear(to_cpumask(l->cpus));
4201    cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4202    nodes_clear(l->nodes);
4203    node_set(page_to_nid(virt_to_page(track)), l->nodes);
4204    return 1;
4205}
4206
4207static void process_slab(struct loc_track *t, struct kmem_cache *s,
4208        struct page *page, enum track_item alloc,
4209        unsigned long *map)
4210{
4211    void *addr = page_address(page);
4212    void *p;
4213
4214    bitmap_zero(map, page->objects);
4215    get_map(s, page, map);
4216
4217    for_each_object(p, s, addr, page->objects)
4218        if (!test_bit(slab_index(p, s, addr), map))
4219            add_location(t, s, get_track(s, p, alloc));
4220}
4221
4222static int list_locations(struct kmem_cache *s, char *buf,
4223                    enum track_item alloc)
4224{
4225    int len = 0;
4226    unsigned long i;
4227    struct loc_track t = { 0, 0, NULL };
4228    int node;
4229    unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4230                     sizeof(unsigned long), GFP_KERNEL);
4231
4232    if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4233                     GFP_TEMPORARY)) {
4234        kfree(map);
4235        return sprintf(buf, "Out of memory\n");
4236    }
4237    /* Push back cpu slabs */
4238    flush_all(s);
4239
4240    for_each_node_state(node, N_NORMAL_MEMORY) {
4241        struct kmem_cache_node *n = get_node(s, node);
4242        unsigned long flags;
4243        struct page *page;
4244
4245        if (!atomic_long_read(&n->nr_slabs))
4246            continue;
4247
4248        spin_lock_irqsave(&n->list_lock, flags);
4249        list_for_each_entry(page, &n->partial, lru)
4250            process_slab(&t, s, page, alloc, map);
4251        list_for_each_entry(page, &n->full, lru)
4252            process_slab(&t, s, page, alloc, map);
4253        spin_unlock_irqrestore(&n->list_lock, flags);
4254    }
4255
4256    for (i = 0; i < t.count; i++) {
4257        struct location *l = &t.loc[i];
4258
4259        if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4260            break;
4261        len += sprintf(buf + len, "%7ld ", l->count);
4262
4263        if (l->addr)
4264            len += sprintf(buf + len, "%pS", (void *)l->addr);
4265        else
4266            len += sprintf(buf + len, "<not-available>");
4267
4268        if (l->sum_time != l->min_time) {
4269            len += sprintf(buf + len, " age=%ld/%ld/%ld",
4270                l->min_time,
4271                (long)div_u64(l->sum_time, l->count),
4272                l->max_time);
4273        } else
4274            len += sprintf(buf + len, " age=%ld",
4275                l->min_time);
4276
4277        if (l->min_pid != l->max_pid)
4278            len += sprintf(buf + len, " pid=%ld-%ld",
4279                l->min_pid, l->max_pid);
4280        else
4281            len += sprintf(buf + len, " pid=%ld",
4282                l->min_pid);
4283
4284        if (num_online_cpus() > 1 &&
4285                !cpumask_empty(to_cpumask(l->cpus)) &&
4286                len < PAGE_SIZE - 60) {
4287            len += sprintf(buf + len, " cpus=");
4288            len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4289                         to_cpumask(l->cpus));
4290        }
4291
4292        if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4293                len < PAGE_SIZE - 60) {
4294            len += sprintf(buf + len, " nodes=");
4295            len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4296                    l->nodes);
4297        }
4298
4299        len += sprintf(buf + len, "\n");
4300    }
4301
4302    free_loc_track(&t);
4303    kfree(map);
4304    if (!t.count)
4305        len += sprintf(buf, "No data\n");
4306    return len;
4307}
4308#endif
4309
4310#ifdef SLUB_RESILIENCY_TEST
4311static void resiliency_test(void)
4312{
4313    u8 *p;
4314
4315    BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10);
4316
4317    printk(KERN_ERR "SLUB resiliency testing\n");
4318    printk(KERN_ERR "-----------------------\n");
4319    printk(KERN_ERR "A. Corruption after allocation\n");
4320
4321    p = kzalloc(16, GFP_KERNEL);
4322    p[16] = 0x12;
4323    printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
4324            " 0x12->0x%p\n\n", p + 16);
4325
4326    validate_slab_cache(kmalloc_caches[4]);
4327
4328    /* Hmmm... The next two are dangerous */
4329    p = kzalloc(32, GFP_KERNEL);
4330    p[32 + sizeof(void *)] = 0x34;
4331    printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
4332            " 0x34 -> -0x%p\n", p);
4333    printk(KERN_ERR
4334        "If allocated object is overwritten then not detectable\n\n");
4335
4336    validate_slab_cache(kmalloc_caches[5]);
4337    p = kzalloc(64, GFP_KERNEL);
4338    p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4339    *p = 0x56;
4340    printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4341                                    p);
4342    printk(KERN_ERR
4343        "If allocated object is overwritten then not detectable\n\n");
4344    validate_slab_cache(kmalloc_caches[6]);
4345
4346    printk(KERN_ERR "\nB. Corruption after free\n");
4347    p = kzalloc(128, GFP_KERNEL);
4348    kfree(p);
4349    *p = 0x78;
4350    printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4351    validate_slab_cache(kmalloc_caches[7]);
4352
4353    p = kzalloc(256, GFP_KERNEL);
4354    kfree(p);
4355    p[50] = 0x9a;
4356    printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4357            p);
4358    validate_slab_cache(kmalloc_caches[8]);
4359
4360    p = kzalloc(512, GFP_KERNEL);
4361    kfree(p);
4362    p[512] = 0xab;
4363    printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4364    validate_slab_cache(kmalloc_caches[9]);
4365}
4366#else
4367#ifdef CONFIG_SYSFS
4368static void resiliency_test(void) {};
4369#endif
4370#endif
4371
4372#ifdef CONFIG_SYSFS
4373enum slab_stat_type {
4374    SL_ALL, /* All slabs */
4375    SL_PARTIAL, /* Only partially allocated slabs */
4376    SL_CPU, /* Only slabs used for cpu caches */
4377    SL_OBJECTS, /* Determine allocated objects not slabs */
4378    SL_TOTAL /* Determine object capacity not slabs */
4379};
4380
4381#define SO_ALL (1 << SL_ALL)
4382#define SO_PARTIAL (1 << SL_PARTIAL)
4383#define SO_CPU (1 << SL_CPU)
4384#define SO_OBJECTS (1 << SL_OBJECTS)
4385#define SO_TOTAL (1 << SL_TOTAL)
4386
4387static ssize_t show_slab_objects(struct kmem_cache *s,
4388                char *buf, unsigned long flags)
4389{
4390    unsigned long total = 0;
4391    int node;
4392    int x;
4393    unsigned long *nodes;
4394    unsigned long *per_cpu;
4395
4396    nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4397    if (!nodes)
4398        return -ENOMEM;
4399    per_cpu = nodes + nr_node_ids;
4400
4401    if (flags & SO_CPU) {
4402        int cpu;
4403
4404        for_each_possible_cpu(cpu) {
4405            struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
4406            int node;
4407            struct page *page;
4408
4409            page = ACCESS_ONCE(c->page);
4410            if (!page)
4411                continue;
4412
4413            node = page_to_nid(page);
4414            if (flags & SO_TOTAL)
4415                x = page->objects;
4416            else if (flags & SO_OBJECTS)
4417                x = page->inuse;
4418            else
4419                x = 1;
4420
4421            total += x;
4422            nodes[node] += x;
4423
4424            page = ACCESS_ONCE(c->partial);
4425            if (page) {
4426                x = page->pobjects;
4427                total += x;
4428                nodes[node] += x;
4429            }
4430
4431            per_cpu[node]++;
4432        }
4433    }
4434
4435    lock_memory_hotplug();
4436#ifdef CONFIG_SLUB_DEBUG
4437    if (flags & SO_ALL) {
4438        for_each_node_state(node, N_NORMAL_MEMORY) {
4439            struct kmem_cache_node *n = get_node(s, node);
4440
4441        if (flags & SO_TOTAL)
4442            x = atomic_long_read(&n->total_objects);
4443        else if (flags & SO_OBJECTS)
4444            x = atomic_long_read(&n->total_objects) -
4445                count_partial(n, count_free);
4446
4447            else
4448                x = atomic_long_read(&n->nr_slabs);
4449            total += x;
4450            nodes[node] += x;
4451        }
4452
4453    } else
4454#endif
4455    if (flags & SO_PARTIAL) {
4456        for_each_node_state(node, N_NORMAL_MEMORY) {
4457            struct kmem_cache_node *n = get_node(s, node);
4458
4459            if (flags & SO_TOTAL)
4460                x = count_partial(n, count_total);
4461            else if (flags & SO_OBJECTS)
4462                x = count_partial(n, count_inuse);
4463            else
4464                x = n->nr_partial;
4465            total += x;
4466            nodes[node] += x;
4467        }
4468    }
4469    x = sprintf(buf, "%lu", total);
4470#ifdef CONFIG_NUMA
4471    for_each_node_state(node, N_NORMAL_MEMORY)
4472        if (nodes[node])
4473            x += sprintf(buf + x, " N%d=%lu",
4474                    node, nodes[node]);
4475#endif
4476    unlock_memory_hotplug();
4477    kfree(nodes);
4478    return x + sprintf(buf + x, "\n");
4479}
4480
4481#ifdef CONFIG_SLUB_DEBUG
4482static int any_slab_objects(struct kmem_cache *s)
4483{
4484    int node;
4485
4486    for_each_online_node(node) {
4487        struct kmem_cache_node *n = get_node(s, node);
4488
4489        if (!n)
4490            continue;
4491
4492        if (atomic_long_read(&n->total_objects))
4493            return 1;
4494    }
4495    return 0;
4496}
4497#endif
4498
4499#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4500#define to_slab(n) container_of(n, struct kmem_cache, kobj)
4501
4502struct slab_attribute {
4503    struct attribute attr;
4504    ssize_t (*show)(struct kmem_cache *s, char *buf);
4505    ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4506};
4507
4508#define SLAB_ATTR_RO(_name) \
4509    static struct slab_attribute _name##_attr = \
4510    __ATTR(_name, 0400, _name##_show, NULL)
4511
4512#define SLAB_ATTR(_name) \
4513    static struct slab_attribute _name##_attr = \
4514    __ATTR(_name, 0600, _name##_show, _name##_store)
4515
4516static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4517{
4518    return sprintf(buf, "%d\n", s->size);
4519}
4520SLAB_ATTR_RO(slab_size);
4521
4522static ssize_t align_show(struct kmem_cache *s, char *buf)
4523{
4524    return sprintf(buf, "%d\n", s->align);
4525}
4526SLAB_ATTR_RO(align);
4527
4528static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4529{
4530    return sprintf(buf, "%d\n", s->object_size);
4531}
4532SLAB_ATTR_RO(object_size);
4533
4534static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4535{
4536    return sprintf(buf, "%d\n", oo_objects(s->oo));
4537}
4538SLAB_ATTR_RO(objs_per_slab);
4539
4540static ssize_t order_store(struct kmem_cache *s,
4541                const char *buf, size_t length)
4542{
4543    unsigned long order;
4544    int err;
4545
4546    err = strict_strtoul(buf, 10, &order);
4547    if (err)
4548        return err;
4549
4550    if (order > slub_max_order || order < slub_min_order)
4551        return -EINVAL;
4552
4553    calculate_sizes(s, order);
4554    return length;
4555}
4556
4557static ssize_t order_show(struct kmem_cache *s, char *buf)
4558{
4559    return sprintf(buf, "%d\n", oo_order(s->oo));
4560}
4561SLAB_ATTR(order);
4562
4563static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4564{
4565    return sprintf(buf, "%lu\n", s->min_partial);
4566}
4567
4568static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4569                 size_t length)
4570{
4571    unsigned long min;
4572    int err;
4573
4574    err = strict_strtoul(buf, 10, &min);
4575    if (err)
4576        return err;
4577
4578    set_min_partial(s, min);
4579    return length;
4580}
4581SLAB_ATTR(min_partial);
4582
4583static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4584{
4585    return sprintf(buf, "%u\n", s->cpu_partial);
4586}
4587
4588static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4589                 size_t length)
4590{
4591    unsigned long objects;
4592    int err;
4593
4594    err = strict_strtoul(buf, 10, &objects);
4595    if (err)
4596        return err;
4597    if (objects && kmem_cache_debug(s))
4598        return -EINVAL;
4599
4600    s->cpu_partial = objects;
4601    flush_all(s);
4602    return length;
4603}
4604SLAB_ATTR(cpu_partial);
4605
4606static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4607{
4608    if (!s->ctor)
4609        return 0;
4610    return sprintf(buf, "%pS\n", s->ctor);
4611}
4612SLAB_ATTR_RO(ctor);
4613
4614static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4615{
4616    return sprintf(buf, "%d\n", s->refcount - 1);
4617}
4618SLAB_ATTR_RO(aliases);
4619
4620static ssize_t partial_show(struct kmem_cache *s, char *buf)
4621{
4622    return show_slab_objects(s, buf, SO_PARTIAL);
4623}
4624SLAB_ATTR_RO(partial);
4625
4626static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4627{
4628    return show_slab_objects(s, buf, SO_CPU);
4629}
4630SLAB_ATTR_RO(cpu_slabs);
4631
4632static ssize_t objects_show(struct kmem_cache *s, char *buf)
4633{
4634    return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4635}
4636SLAB_ATTR_RO(objects);
4637
4638static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4639{
4640    return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4641}
4642SLAB_ATTR_RO(objects_partial);
4643
4644static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4645{
4646    int objects = 0;
4647    int pages = 0;
4648    int cpu;
4649    int len;
4650
4651    for_each_online_cpu(cpu) {
4652        struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4653
4654        if (page) {
4655            pages += page->pages;
4656            objects += page->pobjects;
4657        }
4658    }
4659
4660    len = sprintf(buf, "%d(%d)", objects, pages);
4661
4662#ifdef CONFIG_SMP
4663    for_each_online_cpu(cpu) {
4664        struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4665
4666        if (page && len < PAGE_SIZE - 20)
4667            len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4668                page->pobjects, page->pages);
4669    }
4670#endif
4671    return len + sprintf(buf + len, "\n");
4672}
4673SLAB_ATTR_RO(slabs_cpu_partial);
4674
4675static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4676{
4677    return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4678}
4679
4680static ssize_t reclaim_account_store(struct kmem_cache *s,
4681                const char *buf, size_t length)
4682{
4683    s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4684    if (buf[0] == '1')
4685        s->flags |= SLAB_RECLAIM_ACCOUNT;
4686    return length;
4687}
4688SLAB_ATTR(reclaim_account);
4689
4690static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4691{
4692    return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4693}
4694SLAB_ATTR_RO(hwcache_align);
4695
4696#ifdef CONFIG_ZONE_DMA
4697static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4698{
4699    return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4700}
4701SLAB_ATTR_RO(cache_dma);
4702#endif
4703
4704static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4705{
4706    return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4707}
4708SLAB_ATTR_RO(destroy_by_rcu);
4709
4710static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4711{
4712    return sprintf(buf, "%d\n", s->reserved);
4713}
4714SLAB_ATTR_RO(reserved);
4715
4716#ifdef CONFIG_SLUB_DEBUG
4717static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4718{
4719    return show_slab_objects(s, buf, SO_ALL);
4720}
4721SLAB_ATTR_RO(slabs);
4722
4723static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4724{
4725    return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4726}
4727SLAB_ATTR_RO(total_objects);
4728
4729static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4730{
4731    return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4732}
4733
4734static ssize_t sanity_checks_store(struct kmem_cache *s,
4735                const char *buf, size_t length)
4736{
4737    s->flags &= ~SLAB_DEBUG_FREE;
4738    if (buf[0] == '1') {
4739        s->flags &= ~__CMPXCHG_DOUBLE;
4740        s->flags |= SLAB_DEBUG_FREE;
4741    }
4742    return length;
4743}
4744SLAB_ATTR(sanity_checks);
4745
4746static ssize_t trace_show(struct kmem_cache *s, char *buf)
4747{
4748    return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4749}
4750
4751static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4752                            size_t length)
4753{
4754    s->flags &= ~SLAB_TRACE;
4755    if (buf[0] == '1') {
4756        s->flags &= ~__CMPXCHG_DOUBLE;
4757        s->flags |= SLAB_TRACE;
4758    }
4759    return length;
4760}
4761SLAB_ATTR(trace);
4762
4763static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4764{
4765    return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4766}
4767
4768static ssize_t red_zone_store(struct kmem_cache *s,
4769                const char *buf, size_t length)
4770{
4771    if (any_slab_objects(s))
4772        return -EBUSY;
4773
4774    s->flags &= ~SLAB_RED_ZONE;
4775    if (buf[0] == '1') {
4776        s->flags &= ~__CMPXCHG_DOUBLE;
4777        s->flags |= SLAB_RED_ZONE;
4778    }
4779    calculate_sizes(s, -1);
4780    return length;
4781}
4782SLAB_ATTR(red_zone);
4783
4784static ssize_t poison_show(struct kmem_cache *s, char *buf)
4785{
4786    return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4787}
4788
4789static ssize_t poison_store(struct kmem_cache *s,
4790                const char *buf, size_t length)
4791{
4792    if (any_slab_objects(s))
4793        return -EBUSY;
4794
4795    s->flags &= ~SLAB_POISON;
4796    if (buf[0] == '1') {
4797        s->flags &= ~__CMPXCHG_DOUBLE;
4798        s->flags |= SLAB_POISON;
4799    }
4800    calculate_sizes(s, -1);
4801    return length;
4802}
4803SLAB_ATTR(poison);
4804
4805static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4806{
4807    return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4808}
4809
4810static ssize_t store_user_store(struct kmem_cache *s,
4811                const char *buf, size_t length)
4812{
4813    if (any_slab_objects(s))
4814        return -EBUSY;
4815
4816    s->flags &= ~SLAB_STORE_USER;
4817    if (buf[0] == '1') {
4818        s->flags &= ~__CMPXCHG_DOUBLE;
4819        s->flags |= SLAB_STORE_USER;
4820    }
4821    calculate_sizes(s, -1);
4822    return length;
4823}
4824SLAB_ATTR(store_user);
4825
4826static ssize_t validate_show(struct kmem_cache *s, char *buf)
4827{
4828    return 0;
4829}
4830
4831static ssize_t validate_store(struct kmem_cache *s,
4832            const char *buf, size_t length)
4833{
4834    int ret = -EINVAL;
4835
4836    if (buf[0] == '1') {
4837        ret = validate_slab_cache(s);
4838        if (ret >= 0)
4839            ret = length;
4840    }
4841    return ret;
4842}
4843SLAB_ATTR(validate);
4844
4845static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4846{
4847    if (!(s->flags & SLAB_STORE_USER))
4848        return -ENOSYS;
4849    return list_locations(s, buf, TRACK_ALLOC);
4850}
4851SLAB_ATTR_RO(alloc_calls);
4852
4853static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4854{
4855    if (!(s->flags & SLAB_STORE_USER))
4856        return -ENOSYS;
4857    return list_locations(s, buf, TRACK_FREE);
4858}
4859SLAB_ATTR_RO(free_calls);
4860#endif /* CONFIG_SLUB_DEBUG */
4861
4862#ifdef CONFIG_FAILSLAB
4863static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4864{
4865    return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4866}
4867
4868static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4869                            size_t length)
4870{
4871    s->flags &= ~SLAB_FAILSLAB;
4872    if (buf[0] == '1')
4873        s->flags |= SLAB_FAILSLAB;
4874    return length;
4875}
4876SLAB_ATTR(failslab);
4877#endif
4878
4879static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4880{
4881    return 0;
4882}
4883
4884static ssize_t shrink_store(struct kmem_cache *s,
4885            const char *buf, size_t length)
4886{
4887    if (buf[0] == '1') {
4888        int rc = kmem_cache_shrink(s);
4889
4890        if (rc)
4891            return rc;
4892    } else
4893        return -EINVAL;
4894    return length;
4895}
4896SLAB_ATTR(shrink);
4897
4898#ifdef CONFIG_NUMA
4899static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4900{
4901    return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4902}
4903
4904static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
4905                const char *buf, size_t length)
4906{
4907    unsigned long ratio;
4908    int err;
4909
4910    err = strict_strtoul(buf, 10, &ratio);
4911    if (err)
4912        return err;
4913
4914    if (ratio <= 100)
4915        s->remote_node_defrag_ratio = ratio * 10;
4916
4917    return length;
4918}
4919SLAB_ATTR(remote_node_defrag_ratio);
4920#endif
4921
4922#ifdef CONFIG_SLUB_STATS
4923static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
4924{
4925    unsigned long sum = 0;
4926    int cpu;
4927    int len;
4928    int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
4929
4930    if (!data)
4931        return -ENOMEM;
4932
4933    for_each_online_cpu(cpu) {
4934        unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
4935
4936        data[cpu] = x;
4937        sum += x;
4938    }
4939
4940    len = sprintf(buf, "%lu", sum);
4941
4942#ifdef CONFIG_SMP
4943    for_each_online_cpu(cpu) {
4944        if (data[cpu] && len < PAGE_SIZE - 20)
4945            len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
4946    }
4947#endif
4948    kfree(data);
4949    return len + sprintf(buf + len, "\n");
4950}
4951
4952static void clear_stat(struct kmem_cache *s, enum stat_item si)
4953{
4954    int cpu;
4955
4956    for_each_online_cpu(cpu)
4957        per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
4958}
4959
4960#define STAT_ATTR(si, text) \
4961static ssize_t text##_show(struct kmem_cache *s, char *buf) \
4962{ \
4963    return show_stat(s, buf, si); \
4964} \
4965static ssize_t text##_store(struct kmem_cache *s, \
4966                const char *buf, size_t length) \
4967{ \
4968    if (buf[0] != '0') \
4969        return -EINVAL; \
4970    clear_stat(s, si); \
4971    return length; \
4972} \
4973SLAB_ATTR(text); \
4974
4975STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4976STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
4977STAT_ATTR(FREE_FASTPATH, free_fastpath);
4978STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4979STAT_ATTR(FREE_FROZEN, free_frozen);
4980STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4981STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4982STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4983STAT_ATTR(ALLOC_SLAB, alloc_slab);
4984STAT_ATTR(ALLOC_REFILL, alloc_refill);
4985STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
4986STAT_ATTR(FREE_SLAB, free_slab);
4987STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4988STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4989STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4990STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4991STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4992STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4993STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
4994STAT_ATTR(ORDER_FALLBACK, order_fallback);
4995STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
4996STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
4997STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
4998STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
4999STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5000STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5001#endif
5002
5003static struct attribute *slab_attrs[] = {
5004    &slab_size_attr.attr,
5005    &object_size_attr.attr,
5006    &objs_per_slab_attr.attr,
5007    &order_attr.attr,
5008    &min_partial_attr.attr,
5009    &cpu_partial_attr.attr,
5010    &objects_attr.attr,
5011    &objects_partial_attr.attr,
5012    &partial_attr.attr,
5013    &cpu_slabs_attr.attr,
5014    &ctor_attr.attr,
5015    &aliases_attr.attr,
5016    &align_attr.attr,
5017    &hwcache_align_attr.attr,
5018    &reclaim_account_attr.attr,
5019    &destroy_by_rcu_attr.attr,
5020    &shrink_attr.attr,
5021    &reserved_attr.attr,
5022    &slabs_cpu_partial_attr.attr,
5023#ifdef CONFIG_SLUB_DEBUG
5024    &total_objects_attr.attr,
5025    &slabs_attr.attr,
5026    &sanity_checks_attr.attr,
5027    &trace_attr.attr,
5028    &red_zone_attr.attr,
5029    &poison_attr.attr,
5030    &store_user_attr.attr,
5031    &validate_attr.attr,
5032    &alloc_calls_attr.attr,
5033    &free_calls_attr.attr,
5034#endif
5035#ifdef CONFIG_ZONE_DMA
5036    &cache_dma_attr.attr,
5037#endif
5038#ifdef CONFIG_NUMA
5039    &remote_node_defrag_ratio_attr.attr,
5040#endif
5041#ifdef CONFIG_SLUB_STATS
5042    &alloc_fastpath_attr.attr,
5043    &alloc_slowpath_attr.attr,
5044    &free_fastpath_attr.attr,
5045    &free_slowpath_attr.attr,
5046    &free_frozen_attr.attr,
5047    &free_add_partial_attr.attr,
5048    &free_remove_partial_attr.attr,
5049    &alloc_from_partial_attr.attr,
5050    &alloc_slab_attr.attr,
5051    &alloc_refill_attr.attr,
5052    &alloc_node_mismatch_attr.attr,
5053    &free_slab_attr.attr,
5054    &cpuslab_flush_attr.attr,
5055    &deactivate_full_attr.attr,
5056    &deactivate_empty_attr.attr,
5057    &deactivate_to_head_attr.attr,
5058    &deactivate_to_tail_attr.attr,
5059    &deactivate_remote_frees_attr.attr,
5060    &deactivate_bypass_attr.attr,
5061    &order_fallback_attr.attr,
5062    &cmpxchg_double_fail_attr.attr,
5063    &cmpxchg_double_cpu_fail_attr.attr,
5064    &cpu_partial_alloc_attr.attr,
5065    &cpu_partial_free_attr.attr,
5066    &cpu_partial_node_attr.attr,
5067    &cpu_partial_drain_attr.attr,
5068#endif
5069#ifdef CONFIG_FAILSLAB
5070    &failslab_attr.attr,
5071#endif
5072
5073    NULL
5074};
5075
5076static struct attribute_group slab_attr_group = {
5077    .attrs = slab_attrs,
5078};
5079
5080static ssize_t slab_attr_show(struct kobject *kobj,
5081                struct attribute *attr,
5082                char *buf)
5083{
5084    struct slab_attribute *attribute;
5085    struct kmem_cache *s;
5086    int err;
5087
5088    attribute = to_slab_attr(attr);
5089    s = to_slab(kobj);
5090
5091    if (!attribute->show)
5092        return -EIO;
5093
5094    err = attribute->show(s, buf);
5095
5096    return err;
5097}
5098
5099static ssize_t slab_attr_store(struct kobject *kobj,
5100                struct attribute *attr,
5101                const char *buf, size_t len)
5102{
5103    struct slab_attribute *attribute;
5104    struct kmem_cache *s;
5105    int err;
5106
5107    attribute = to_slab_attr(attr);
5108    s = to_slab(kobj);
5109
5110    if (!attribute->store)
5111        return -EIO;
5112
5113    err = attribute->store(s, buf, len);
5114#ifdef CONFIG_MEMCG_KMEM
5115    if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5116        int i;
5117
5118        mutex_lock(&slab_mutex);
5119        if (s->max_attr_size < len)
5120            s->max_attr_size = len;
5121
5122        /*
5123         * This is a best effort propagation, so this function's return
5124         * value will be determined by the parent cache only. This is
5125         * basically because not all attributes will have a well
5126         * defined semantics for rollbacks - most of the actions will
5127         * have permanent effects.
5128         *
5129         * Returning the error value of any of the children that fail
5130         * is not 100 % defined, in the sense that users seeing the
5131         * error code won't be able to know anything about the state of
5132         * the cache.
5133         *
5134         * Only returning the error code for the parent cache at least
5135         * has well defined semantics. The cache being written to
5136         * directly either failed or succeeded, in which case we loop
5137         * through the descendants with best-effort propagation.
5138         */
5139        for_each_memcg_cache_index(i) {
5140            struct kmem_cache *c = cache_from_memcg(s, i);
5141            if (c)
5142                attribute->store(c, buf, len);
5143        }
5144        mutex_unlock(&slab_mutex);
5145    }
5146#endif
5147    return err;
5148}
5149
5150static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5151{
5152#ifdef CONFIG_MEMCG_KMEM
5153    int i;
5154    char *buffer = NULL;
5155
5156    if (!is_root_cache(s))
5157        return;
5158
5159    /*
5160     * This mean this cache had no attribute written. Therefore, no point
5161     * in copying default values around
5162     */
5163    if (!s->max_attr_size)
5164        return;
5165
5166    for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5167        char mbuf[64];
5168        char *buf;
5169        struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5170
5171        if (!attr || !attr->store || !attr->show)
5172            continue;
5173
5174        /*
5175         * It is really bad that we have to allocate here, so we will
5176         * do it only as a fallback. If we actually allocate, though,
5177         * we can just use the allocated buffer until the end.
5178         *
5179         * Most of the slub attributes will tend to be very small in
5180         * size, but sysfs allows buffers up to a page, so they can
5181         * theoretically happen.
5182         */
5183        if (buffer)
5184            buf = buffer;
5185        else if (s->max_attr_size < ARRAY_SIZE(mbuf))
5186            buf = mbuf;
5187        else {
5188            buffer = (char *) get_zeroed_page(GFP_KERNEL);
5189            if (WARN_ON(!buffer))
5190                continue;
5191            buf = buffer;
5192        }
5193
5194        attr->show(s->memcg_params->root_cache, buf);
5195        attr->store(s, buf, strlen(buf));
5196    }
5197
5198    if (buffer)
5199        free_page((unsigned long)buffer);
5200#endif
5201}
5202
5203static const struct sysfs_ops slab_sysfs_ops = {
5204    .show = slab_attr_show,
5205    .store = slab_attr_store,
5206};
5207
5208static struct kobj_type slab_ktype = {
5209    .sysfs_ops = &slab_sysfs_ops,
5210};
5211
5212static int uevent_filter(struct kset *kset, struct kobject *kobj)
5213{
5214    struct kobj_type *ktype = get_ktype(kobj);
5215
5216    if (ktype == &slab_ktype)
5217        return 1;
5218    return 0;
5219}
5220
5221static const struct kset_uevent_ops slab_uevent_ops = {
5222    .filter = uevent_filter,
5223};
5224
5225static struct kset *slab_kset;
5226
5227#define ID_STR_LENGTH 64
5228
5229/* Create a unique string id for a slab cache:
5230 *
5231 * Format :[flags-]size
5232 */
5233static char *create_unique_id(struct kmem_cache *s)
5234{
5235    char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5236    char *p = name;
5237
5238    BUG_ON(!name);
5239
5240    *p++ = ':';
5241    /*
5242     * First flags affecting slabcache operations. We will only
5243     * get here for aliasable slabs so we do not need to support
5244     * too many flags. The flags here must cover all flags that
5245     * are matched during merging to guarantee that the id is
5246     * unique.
5247     */
5248    if (s->flags & SLAB_CACHE_DMA)
5249        *p++ = 'd';
5250    if (s->flags & SLAB_RECLAIM_ACCOUNT)
5251        *p++ = 'a';
5252    if (s->flags & SLAB_DEBUG_FREE)
5253        *p++ = 'F';
5254    if (!(s->flags & SLAB_NOTRACK))
5255        *p++ = 't';
5256    if (p != name + 1)
5257        *p++ = '-';
5258    p += sprintf(p, "%07d", s->size);
5259
5260#ifdef CONFIG_MEMCG_KMEM
5261    if (!is_root_cache(s))
5262        p += sprintf(p, "-%08d", memcg_cache_id(s->memcg_params->memcg));
5263#endif
5264
5265    BUG_ON(p > name + ID_STR_LENGTH - 1);
5266    return name;
5267}
5268
5269static int sysfs_slab_add(struct kmem_cache *s)
5270{
5271    int err;
5272    const char *name;
5273    int unmergeable = slab_unmergeable(s);
5274
5275    if (unmergeable) {
5276        /*
5277         * Slabcache can never be merged so we can use the name proper.
5278         * This is typically the case for debug situations. In that
5279         * case we can catch duplicate names easily.
5280         */
5281        sysfs_remove_link(&slab_kset->kobj, s->name);
5282        name = s->name;
5283    } else {
5284        /*
5285         * Create a unique name for the slab as a target
5286         * for the symlinks.
5287         */
5288        name = create_unique_id(s);
5289    }
5290
5291    s->kobj.kset = slab_kset;
5292    err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
5293    if (err) {
5294        kobject_put(&s->kobj);
5295        return err;
5296    }
5297
5298    err = sysfs_create_group(&s->kobj, &slab_attr_group);
5299    if (err) {
5300        kobject_del(&s->kobj);
5301        kobject_put(&s->kobj);
5302        return err;
5303    }
5304    kobject_uevent(&s->kobj, KOBJ_ADD);
5305    if (!unmergeable) {
5306        /* Setup first alias */
5307        sysfs_slab_alias(s, s->name);
5308        kfree(name);
5309    }
5310    return 0;
5311}
5312
5313static void sysfs_slab_remove(struct kmem_cache *s)
5314{
5315    if (slab_state < FULL)
5316        /*
5317         * Sysfs has not been setup yet so no need to remove the
5318         * cache from sysfs.
5319         */
5320        return;
5321
5322    kobject_uevent(&s->kobj, KOBJ_REMOVE);
5323    kobject_del(&s->kobj);
5324    kobject_put(&s->kobj);
5325}
5326
5327/*
5328 * Need to buffer aliases during bootup until sysfs becomes
5329 * available lest we lose that information.
5330 */
5331struct saved_alias {
5332    struct kmem_cache *s;
5333    const char *name;
5334    struct saved_alias *next;
5335};
5336
5337static struct saved_alias *alias_list;
5338
5339static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5340{
5341    struct saved_alias *al;
5342
5343    if (slab_state == FULL) {
5344        /*
5345         * If we have a leftover link then remove it.
5346         */
5347        sysfs_remove_link(&slab_kset->kobj, name);
5348        return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5349    }
5350
5351    al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5352    if (!al)
5353        return -ENOMEM;
5354
5355    al->s = s;
5356    al->name = name;
5357    al->next = alias_list;
5358    alias_list = al;
5359    return 0;
5360}
5361
5362static int __init slab_sysfs_init(void)
5363{
5364    struct kmem_cache *s;
5365    int err;
5366
5367    mutex_lock(&slab_mutex);
5368
5369    slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5370    if (!slab_kset) {
5371        mutex_unlock(&slab_mutex);
5372        printk(KERN_ERR "Cannot register slab subsystem.\n");
5373        return -ENOSYS;
5374    }
5375
5376    slab_state = FULL;
5377
5378    list_for_each_entry(s, &slab_caches, list) {
5379        err = sysfs_slab_add(s);
5380        if (err)
5381            printk(KERN_ERR "SLUB: Unable to add boot slab %s"
5382                        " to sysfs\n", s->name);
5383    }
5384
5385    while (alias_list) {
5386        struct saved_alias *al = alias_list;
5387
5388        alias_list = alias_list->next;
5389        err = sysfs_slab_alias(al->s, al->name);
5390        if (err)
5391            printk(KERN_ERR "SLUB: Unable to add boot slab alias"
5392                    " %s to sysfs\n", al->name);
5393        kfree(al);
5394    }
5395
5396    mutex_unlock(&slab_mutex);
5397    resiliency_test();
5398    return 0;
5399}
5400
5401__initcall(slab_sysfs_init);
5402#endif /* CONFIG_SYSFS */
5403
5404/*
5405 * The /proc/slabinfo ABI
5406 */
5407#ifdef CONFIG_SLABINFO
5408void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5409{
5410    unsigned long nr_partials = 0;
5411    unsigned long nr_slabs = 0;
5412    unsigned long nr_objs = 0;
5413    unsigned long nr_free = 0;
5414    int node;
5415
5416    for_each_online_node(node) {
5417        struct kmem_cache_node *n = get_node(s, node);
5418
5419        if (!n)
5420            continue;
5421
5422        nr_partials += n->nr_partial;
5423        nr_slabs += atomic_long_read(&n->nr_slabs);
5424        nr_objs += atomic_long_read(&n->total_objects);
5425        nr_free += count_partial(n, count_free);
5426    }
5427
5428    sinfo->active_objs = nr_objs - nr_free;
5429    sinfo->num_objs = nr_objs;
5430    sinfo->active_slabs = nr_slabs;
5431    sinfo->num_slabs = nr_slabs;
5432    sinfo->objects_per_slab = oo_objects(s->oo);
5433    sinfo->cache_order = oo_order(s->oo);
5434}
5435
5436void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5437{
5438}
5439
5440ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5441               size_t count, loff_t *ppos)
5442{
5443    return -EIO;
5444}
5445#endif /* CONFIG_SLABINFO */
5446

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