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TOMOYO Linux Cross Reference
Linux/mm/slub.c

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  1 /*
  2  * SLUB: A slab allocator that limits cache line use instead of queuing
  3  * objects in per cpu and per node lists.
  4  *
  5  * The allocator synchronizes using per slab locks or atomic operatios
  6  * and only uses a centralized lock to manage a pool of partial slabs.
  7  *
  8  * (C) 2007 SGI, Christoph Lameter
  9  * (C) 2011 Linux Foundation, Christoph Lameter
 10  */
 11 
 12 #include <linux/mm.h>
 13 #include <linux/swap.h> /* struct reclaim_state */
 14 #include <linux/module.h>
 15 #include <linux/bit_spinlock.h>
 16 #include <linux/interrupt.h>
 17 #include <linux/bitops.h>
 18 #include <linux/slab.h>
 19 #include "slab.h"
 20 #include <linux/proc_fs.h>
 21 #include <linux/notifier.h>
 22 #include <linux/seq_file.h>
 23 #include <linux/kmemcheck.h>
 24 #include <linux/cpu.h>
 25 #include <linux/cpuset.h>
 26 #include <linux/mempolicy.h>
 27 #include <linux/ctype.h>
 28 #include <linux/debugobjects.h>
 29 #include <linux/kallsyms.h>
 30 #include <linux/memory.h>
 31 #include <linux/math64.h>
 32 #include <linux/fault-inject.h>
 33 #include <linux/stacktrace.h>
 34 #include <linux/prefetch.h>
 35 #include <linux/memcontrol.h>
 36 
 37 #include <trace/events/kmem.h>
 38 
 39 #include "internal.h"
 40 
 41 /*
 42  * Lock order:
 43  *   1. slab_mutex (Global Mutex)
 44  *   2. node->list_lock
 45  *   3. slab_lock(page) (Only on some arches and for debugging)
 46  *
 47  *   slab_mutex
 48  *
 49  *   The role of the slab_mutex is to protect the list of all the slabs
 50  *   and to synchronize major metadata changes to slab cache structures.
 51  *
 52  *   The slab_lock is only used for debugging and on arches that do not
 53  *   have the ability to do a cmpxchg_double. It only protects the second
 54  *   double word in the page struct. Meaning
 55  *      A. page->freelist       -> List of object free in a page
 56  *      B. page->counters       -> Counters of objects
 57  *      C. page->frozen         -> frozen state
 58  *
 59  *   If a slab is frozen then it is exempt from list management. It is not
 60  *   on any list. The processor that froze the slab is the one who can
 61  *   perform list operations on the page. Other processors may put objects
 62  *   onto the freelist but the processor that froze the slab is the only
 63  *   one that can retrieve the objects from the page's freelist.
 64  *
 65  *   The list_lock protects the partial and full list on each node and
 66  *   the partial slab counter. If taken then no new slabs may be added or
 67  *   removed from the lists nor make the number of partial slabs be modified.
 68  *   (Note that the total number of slabs is an atomic value that may be
 69  *   modified without taking the list lock).
 70  *
 71  *   The list_lock is a centralized lock and thus we avoid taking it as
 72  *   much as possible. As long as SLUB does not have to handle partial
 73  *   slabs, operations can continue without any centralized lock. F.e.
 74  *   allocating a long series of objects that fill up slabs does not require
 75  *   the list lock.
 76  *   Interrupts are disabled during allocation and deallocation in order to
 77  *   make the slab allocator safe to use in the context of an irq. In addition
 78  *   interrupts are disabled to ensure that the processor does not change
 79  *   while handling per_cpu slabs, due to kernel preemption.
 80  *
 81  * SLUB assigns one slab for allocation to each processor.
 82  * Allocations only occur from these slabs called cpu slabs.
 83  *
 84  * Slabs with free elements are kept on a partial list and during regular
 85  * operations no list for full slabs is used. If an object in a full slab is
 86  * freed then the slab will show up again on the partial lists.
 87  * We track full slabs for debugging purposes though because otherwise we
 88  * cannot scan all objects.
 89  *
 90  * Slabs are freed when they become empty. Teardown and setup is
 91  * minimal so we rely on the page allocators per cpu caches for
 92  * fast frees and allocs.
 93  *
 94  * Overloading of page flags that are otherwise used for LRU management.
 95  *
 96  * PageActive           The slab is frozen and exempt from list processing.
 97  *                      This means that the slab is dedicated to a purpose
 98  *                      such as satisfying allocations for a specific
 99  *                      processor. Objects may be freed in the slab while
100  *                      it is frozen but slab_free will then skip the usual
101  *                      list operations. It is up to the processor holding
102  *                      the slab to integrate the slab into the slab lists
103  *                      when the slab is no longer needed.
104  *
105  *                      One use of this flag is to mark slabs that are
106  *                      used for allocations. Then such a slab becomes a cpu
107  *                      slab. The cpu slab may be equipped with an additional
108  *                      freelist that allows lockless access to
109  *                      free objects in addition to the regular freelist
110  *                      that requires the slab lock.
111  *
112  * PageError            Slab requires special handling due to debug
113  *                      options set. This moves slab handling out of
114  *                      the fast path and disables lockless freelists.
115  */
116 
117 static inline int kmem_cache_debug(struct kmem_cache *s)
118 {
119 #ifdef CONFIG_SLUB_DEBUG
120         return unlikely(s->flags & SLAB_DEBUG_FLAGS);
121 #else
122         return 0;
123 #endif
124 }
125 
126 static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
127 {
128 #ifdef CONFIG_SLUB_CPU_PARTIAL
129         return !kmem_cache_debug(s);
130 #else
131         return false;
132 #endif
133 }
134 
135 /*
136  * Issues still to be resolved:
137  *
138  * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
139  *
140  * - Variable sizing of the per node arrays
141  */
142 
143 /* Enable to test recovery from slab corruption on boot */
144 #undef SLUB_RESILIENCY_TEST
145 
146 /* Enable to log cmpxchg failures */
147 #undef SLUB_DEBUG_CMPXCHG
148 
149 /*
150  * Mininum number of partial slabs. These will be left on the partial
151  * lists even if they are empty. kmem_cache_shrink may reclaim them.
152  */
153 #define MIN_PARTIAL 5
154 
155 /*
156  * Maximum number of desirable partial slabs.
157  * The existence of more partial slabs makes kmem_cache_shrink
158  * sort the partial list by the number of objects in the.
159  */
160 #define MAX_PARTIAL 10
161 
162 #define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
163                                 SLAB_POISON | SLAB_STORE_USER)
164 
165 /*
166  * Debugging flags that require metadata to be stored in the slab.  These get
167  * disabled when slub_debug=O is used and a cache's min order increases with
168  * metadata.
169  */
170 #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
171 
172 /*
173  * Set of flags that will prevent slab merging
174  */
175 #define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
176                 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
177                 SLAB_FAILSLAB)
178 
179 #define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
180                 SLAB_CACHE_DMA | SLAB_NOTRACK)
181 
182 #define OO_SHIFT        16
183 #define OO_MASK         ((1 << OO_SHIFT) - 1)
184 #define MAX_OBJS_PER_PAGE       32767 /* since page.objects is u15 */
185 
186 /* Internal SLUB flags */
187 #define __OBJECT_POISON         0x80000000UL /* Poison object */
188 #define __CMPXCHG_DOUBLE        0x40000000UL /* Use cmpxchg_double */
189 
190 #ifdef CONFIG_SMP
191 static struct notifier_block slab_notifier;
192 #endif
193 
194 /*
195  * Tracking user of a slab.
196  */
197 #define TRACK_ADDRS_COUNT 16
198 struct track {
199         unsigned long addr;     /* Called from address */
200 #ifdef CONFIG_STACKTRACE
201         unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
202 #endif
203         int cpu;                /* Was running on cpu */
204         int pid;                /* Pid context */
205         unsigned long when;     /* When did the operation occur */
206 };
207 
208 enum track_item { TRACK_ALLOC, TRACK_FREE };
209 
210 #ifdef CONFIG_SYSFS
211 static int sysfs_slab_add(struct kmem_cache *);
212 static int sysfs_slab_alias(struct kmem_cache *, const char *);
213 static void sysfs_slab_remove(struct kmem_cache *);
214 static void memcg_propagate_slab_attrs(struct kmem_cache *s);
215 #else
216 static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
217 static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
218                                                         { return 0; }
219 static inline void sysfs_slab_remove(struct kmem_cache *s) { }
220 
221 static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
222 #endif
223 
224 static inline void stat(const struct kmem_cache *s, enum stat_item si)
225 {
226 #ifdef CONFIG_SLUB_STATS
227         __this_cpu_inc(s->cpu_slab->stat[si]);
228 #endif
229 }
230 
231 /********************************************************************
232  *                      Core slab cache functions
233  *******************************************************************/
234 
235 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
236 {
237         return s->node[node];
238 }
239 
240 /* Verify that a pointer has an address that is valid within a slab page */
241 static inline int check_valid_pointer(struct kmem_cache *s,
242                                 struct page *page, const void *object)
243 {
244         void *base;
245 
246         if (!object)
247                 return 1;
248 
249         base = page_address(page);
250         if (object < base || object >= base + page->objects * s->size ||
251                 (object - base) % s->size) {
252                 return 0;
253         }
254 
255         return 1;
256 }
257 
258 static inline void *get_freepointer(struct kmem_cache *s, void *object)
259 {
260         return *(void **)(object + s->offset);
261 }
262 
263 static void prefetch_freepointer(const struct kmem_cache *s, void *object)
264 {
265         prefetch(object + s->offset);
266 }
267 
268 static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
269 {
270         void *p;
271 
272 #ifdef CONFIG_DEBUG_PAGEALLOC
273         probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
274 #else
275         p = get_freepointer(s, object);
276 #endif
277         return p;
278 }
279 
280 static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
281 {
282         *(void **)(object + s->offset) = fp;
283 }
284 
285 /* Loop over all objects in a slab */
286 #define for_each_object(__p, __s, __addr, __objects) \
287         for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
288                         __p += (__s)->size)
289 
290 /* Determine object index from a given position */
291 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
292 {
293         return (p - addr) / s->size;
294 }
295 
296 static inline size_t slab_ksize(const struct kmem_cache *s)
297 {
298 #ifdef CONFIG_SLUB_DEBUG
299         /*
300          * Debugging requires use of the padding between object
301          * and whatever may come after it.
302          */
303         if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
304                 return s->object_size;
305 
306 #endif
307         /*
308          * If we have the need to store the freelist pointer
309          * back there or track user information then we can
310          * only use the space before that information.
311          */
312         if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
313                 return s->inuse;
314         /*
315          * Else we can use all the padding etc for the allocation
316          */
317         return s->size;
318 }
319 
320 static inline int order_objects(int order, unsigned long size, int reserved)
321 {
322         return ((PAGE_SIZE << order) - reserved) / size;
323 }
324 
325 static inline struct kmem_cache_order_objects oo_make(int order,
326                 unsigned long size, int reserved)
327 {
328         struct kmem_cache_order_objects x = {
329                 (order << OO_SHIFT) + order_objects(order, size, reserved)
330         };
331 
332         return x;
333 }
334 
335 static inline int oo_order(struct kmem_cache_order_objects x)
336 {
337         return x.x >> OO_SHIFT;
338 }
339 
340 static inline int oo_objects(struct kmem_cache_order_objects x)
341 {
342         return x.x & OO_MASK;
343 }
344 
345 /*
346  * Per slab locking using the pagelock
347  */
348 static __always_inline void slab_lock(struct page *page)
349 {
350         bit_spin_lock(PG_locked, &page->flags);
351 }
352 
353 static __always_inline void slab_unlock(struct page *page)
354 {
355         __bit_spin_unlock(PG_locked, &page->flags);
356 }
357 
358 /* Interrupts must be disabled (for the fallback code to work right) */
359 static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
360                 void *freelist_old, unsigned long counters_old,
361                 void *freelist_new, unsigned long counters_new,
362                 const char *n)
363 {
364         VM_BUG_ON(!irqs_disabled());
365 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
366     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
367         if (s->flags & __CMPXCHG_DOUBLE) {
368                 if (cmpxchg_double(&page->freelist, &page->counters,
369                         freelist_old, counters_old,
370                         freelist_new, counters_new))
371                 return 1;
372         } else
373 #endif
374         {
375                 slab_lock(page);
376                 if (page->freelist == freelist_old && page->counters == counters_old) {
377                         page->freelist = freelist_new;
378                         page->counters = counters_new;
379                         slab_unlock(page);
380                         return 1;
381                 }
382                 slab_unlock(page);
383         }
384 
385         cpu_relax();
386         stat(s, CMPXCHG_DOUBLE_FAIL);
387 
388 #ifdef SLUB_DEBUG_CMPXCHG
389         printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
390 #endif
391 
392         return 0;
393 }
394 
395 static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
396                 void *freelist_old, unsigned long counters_old,
397                 void *freelist_new, unsigned long counters_new,
398                 const char *n)
399 {
400 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
401     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
402         if (s->flags & __CMPXCHG_DOUBLE) {
403                 if (cmpxchg_double(&page->freelist, &page->counters,
404                         freelist_old, counters_old,
405                         freelist_new, counters_new))
406                 return 1;
407         } else
408 #endif
409         {
410                 unsigned long flags;
411 
412                 local_irq_save(flags);
413                 slab_lock(page);
414                 if (page->freelist == freelist_old && page->counters == counters_old) {
415                         page->freelist = freelist_new;
416                         page->counters = counters_new;
417                         slab_unlock(page);
418                         local_irq_restore(flags);
419                         return 1;
420                 }
421                 slab_unlock(page);
422                 local_irq_restore(flags);
423         }
424 
425         cpu_relax();
426         stat(s, CMPXCHG_DOUBLE_FAIL);
427 
428 #ifdef SLUB_DEBUG_CMPXCHG
429         printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
430 #endif
431 
432         return 0;
433 }
434 
435 #ifdef CONFIG_SLUB_DEBUG
436 /*
437  * Determine a map of object in use on a page.
438  *
439  * Node listlock must be held to guarantee that the page does
440  * not vanish from under us.
441  */
442 static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
443 {
444         void *p;
445         void *addr = page_address(page);
446 
447         for (p = page->freelist; p; p = get_freepointer(s, p))
448                 set_bit(slab_index(p, s, addr), map);
449 }
450 
451 /*
452  * Debug settings:
453  */
454 #ifdef CONFIG_SLUB_DEBUG_ON
455 static int slub_debug = DEBUG_DEFAULT_FLAGS;
456 #else
457 static int slub_debug;
458 #endif
459 
460 static char *slub_debug_slabs;
461 static int disable_higher_order_debug;
462 
463 /*
464  * Object debugging
465  */
466 static void print_section(char *text, u8 *addr, unsigned int length)
467 {
468         print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
469                         length, 1);
470 }
471 
472 static struct track *get_track(struct kmem_cache *s, void *object,
473         enum track_item alloc)
474 {
475         struct track *p;
476 
477         if (s->offset)
478                 p = object + s->offset + sizeof(void *);
479         else
480                 p = object + s->inuse;
481 
482         return p + alloc;
483 }
484 
485 static void set_track(struct kmem_cache *s, void *object,
486                         enum track_item alloc, unsigned long addr)
487 {
488         struct track *p = get_track(s, object, alloc);
489 
490         if (addr) {
491 #ifdef CONFIG_STACKTRACE
492                 struct stack_trace trace;
493                 int i;
494 
495                 trace.nr_entries = 0;
496                 trace.max_entries = TRACK_ADDRS_COUNT;
497                 trace.entries = p->addrs;
498                 trace.skip = 3;
499                 save_stack_trace(&trace);
500 
501                 /* See rant in lockdep.c */
502                 if (trace.nr_entries != 0 &&
503                     trace.entries[trace.nr_entries - 1] == ULONG_MAX)
504                         trace.nr_entries--;
505 
506                 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
507                         p->addrs[i] = 0;
508 #endif
509                 p->addr = addr;
510                 p->cpu = smp_processor_id();
511                 p->pid = current->pid;
512                 p->when = jiffies;
513         } else
514                 memset(p, 0, sizeof(struct track));
515 }
516 
517 static void init_tracking(struct kmem_cache *s, void *object)
518 {
519         if (!(s->flags & SLAB_STORE_USER))
520                 return;
521 
522         set_track(s, object, TRACK_FREE, 0UL);
523         set_track(s, object, TRACK_ALLOC, 0UL);
524 }
525 
526 static void print_track(const char *s, struct track *t)
527 {
528         if (!t->addr)
529                 return;
530 
531         printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
532                 s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
533 #ifdef CONFIG_STACKTRACE
534         {
535                 int i;
536                 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
537                         if (t->addrs[i])
538                                 printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
539                         else
540                                 break;
541         }
542 #endif
543 }
544 
545 static void print_tracking(struct kmem_cache *s, void *object)
546 {
547         if (!(s->flags & SLAB_STORE_USER))
548                 return;
549 
550         print_track("Allocated", get_track(s, object, TRACK_ALLOC));
551         print_track("Freed", get_track(s, object, TRACK_FREE));
552 }
553 
554 static void print_page_info(struct page *page)
555 {
556         printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
557                 page, page->objects, page->inuse, page->freelist, page->flags);
558 
559 }
560 
561 static void slab_bug(struct kmem_cache *s, char *fmt, ...)
562 {
563         va_list args;
564         char buf[100];
565 
566         va_start(args, fmt);
567         vsnprintf(buf, sizeof(buf), fmt, args);
568         va_end(args);
569         printk(KERN_ERR "========================================"
570                         "=====================================\n");
571         printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
572         printk(KERN_ERR "----------------------------------------"
573                         "-------------------------------------\n\n");
574 
575         add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
576 }
577 
578 static void slab_fix(struct kmem_cache *s, char *fmt, ...)
579 {
580         va_list args;
581         char buf[100];
582 
583         va_start(args, fmt);
584         vsnprintf(buf, sizeof(buf), fmt, args);
585         va_end(args);
586         printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
587 }
588 
589 static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
590 {
591         unsigned int off;       /* Offset of last byte */
592         u8 *addr = page_address(page);
593 
594         print_tracking(s, p);
595 
596         print_page_info(page);
597 
598         printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
599                         p, p - addr, get_freepointer(s, p));
600 
601         if (p > addr + 16)
602                 print_section("Bytes b4 ", p - 16, 16);
603 
604         print_section("Object ", p, min_t(unsigned long, s->object_size,
605                                 PAGE_SIZE));
606         if (s->flags & SLAB_RED_ZONE)
607                 print_section("Redzone ", p + s->object_size,
608                         s->inuse - s->object_size);
609 
610         if (s->offset)
611                 off = s->offset + sizeof(void *);
612         else
613                 off = s->inuse;
614 
615         if (s->flags & SLAB_STORE_USER)
616                 off += 2 * sizeof(struct track);
617 
618         if (off != s->size)
619                 /* Beginning of the filler is the free pointer */
620                 print_section("Padding ", p + off, s->size - off);
621 
622         dump_stack();
623 }
624 
625 static void object_err(struct kmem_cache *s, struct page *page,
626                         u8 *object, char *reason)
627 {
628         slab_bug(s, "%s", reason);
629         print_trailer(s, page, object);
630 }
631 
632 static void slab_err(struct kmem_cache *s, struct page *page, const char *fmt, ...)
633 {
634         va_list args;
635         char buf[100];
636 
637         va_start(args, fmt);
638         vsnprintf(buf, sizeof(buf), fmt, args);
639         va_end(args);
640         slab_bug(s, "%s", buf);
641         print_page_info(page);
642         dump_stack();
643 }
644 
645 static void init_object(struct kmem_cache *s, void *object, u8 val)
646 {
647         u8 *p = object;
648 
649         if (s->flags & __OBJECT_POISON) {
650                 memset(p, POISON_FREE, s->object_size - 1);
651                 p[s->object_size - 1] = POISON_END;
652         }
653 
654         if (s->flags & SLAB_RED_ZONE)
655                 memset(p + s->object_size, val, s->inuse - s->object_size);
656 }
657 
658 static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
659                                                 void *from, void *to)
660 {
661         slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
662         memset(from, data, to - from);
663 }
664 
665 static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
666                         u8 *object, char *what,
667                         u8 *start, unsigned int value, unsigned int bytes)
668 {
669         u8 *fault;
670         u8 *end;
671 
672         fault = memchr_inv(start, value, bytes);
673         if (!fault)
674                 return 1;
675 
676         end = start + bytes;
677         while (end > fault && end[-1] == value)
678                 end--;
679 
680         slab_bug(s, "%s overwritten", what);
681         printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
682                                         fault, end - 1, fault[0], value);
683         print_trailer(s, page, object);
684 
685         restore_bytes(s, what, value, fault, end);
686         return 0;
687 }
688 
689 /*
690  * Object layout:
691  *
692  * object address
693  *      Bytes of the object to be managed.
694  *      If the freepointer may overlay the object then the free
695  *      pointer is the first word of the object.
696  *
697  *      Poisoning uses 0x6b (POISON_FREE) and the last byte is
698  *      0xa5 (POISON_END)
699  *
700  * object + s->object_size
701  *      Padding to reach word boundary. This is also used for Redzoning.
702  *      Padding is extended by another word if Redzoning is enabled and
703  *      object_size == inuse.
704  *
705  *      We fill with 0xbb (RED_INACTIVE) for inactive objects and with
706  *      0xcc (RED_ACTIVE) for objects in use.
707  *
708  * object + s->inuse
709  *      Meta data starts here.
710  *
711  *      A. Free pointer (if we cannot overwrite object on free)
712  *      B. Tracking data for SLAB_STORE_USER
713  *      C. Padding to reach required alignment boundary or at mininum
714  *              one word if debugging is on to be able to detect writes
715  *              before the word boundary.
716  *
717  *      Padding is done using 0x5a (POISON_INUSE)
718  *
719  * object + s->size
720  *      Nothing is used beyond s->size.
721  *
722  * If slabcaches are merged then the object_size and inuse boundaries are mostly
723  * ignored. And therefore no slab options that rely on these boundaries
724  * may be used with merged slabcaches.
725  */
726 
727 static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
728 {
729         unsigned long off = s->inuse;   /* The end of info */
730 
731         if (s->offset)
732                 /* Freepointer is placed after the object. */
733                 off += sizeof(void *);
734 
735         if (s->flags & SLAB_STORE_USER)
736                 /* We also have user information there */
737                 off += 2 * sizeof(struct track);
738 
739         if (s->size == off)
740                 return 1;
741 
742         return check_bytes_and_report(s, page, p, "Object padding",
743                                 p + off, POISON_INUSE, s->size - off);
744 }
745 
746 /* Check the pad bytes at the end of a slab page */
747 static int slab_pad_check(struct kmem_cache *s, struct page *page)
748 {
749         u8 *start;
750         u8 *fault;
751         u8 *end;
752         int length;
753         int remainder;
754 
755         if (!(s->flags & SLAB_POISON))
756                 return 1;
757 
758         start = page_address(page);
759         length = (PAGE_SIZE << compound_order(page)) - s->reserved;
760         end = start + length;
761         remainder = length % s->size;
762         if (!remainder)
763                 return 1;
764 
765         fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
766         if (!fault)
767                 return 1;
768         while (end > fault && end[-1] == POISON_INUSE)
769                 end--;
770 
771         slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
772         print_section("Padding ", end - remainder, remainder);
773 
774         restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
775         return 0;
776 }
777 
778 static int check_object(struct kmem_cache *s, struct page *page,
779                                         void *object, u8 val)
780 {
781         u8 *p = object;
782         u8 *endobject = object + s->object_size;
783 
784         if (s->flags & SLAB_RED_ZONE) {
785                 if (!check_bytes_and_report(s, page, object, "Redzone",
786                         endobject, val, s->inuse - s->object_size))
787                         return 0;
788         } else {
789                 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
790                         check_bytes_and_report(s, page, p, "Alignment padding",
791                                 endobject, POISON_INUSE, s->inuse - s->object_size);
792                 }
793         }
794 
795         if (s->flags & SLAB_POISON) {
796                 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
797                         (!check_bytes_and_report(s, page, p, "Poison", p,
798                                         POISON_FREE, s->object_size - 1) ||
799                          !check_bytes_and_report(s, page, p, "Poison",
800                                 p + s->object_size - 1, POISON_END, 1)))
801                         return 0;
802                 /*
803                  * check_pad_bytes cleans up on its own.
804                  */
805                 check_pad_bytes(s, page, p);
806         }
807 
808         if (!s->offset && val == SLUB_RED_ACTIVE)
809                 /*
810                  * Object and freepointer overlap. Cannot check
811                  * freepointer while object is allocated.
812                  */
813                 return 1;
814 
815         /* Check free pointer validity */
816         if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
817                 object_err(s, page, p, "Freepointer corrupt");
818                 /*
819                  * No choice but to zap it and thus lose the remainder
820                  * of the free objects in this slab. May cause
821                  * another error because the object count is now wrong.
822                  */
823                 set_freepointer(s, p, NULL);
824                 return 0;
825         }
826         return 1;
827 }
828 
829 static int check_slab(struct kmem_cache *s, struct page *page)
830 {
831         int maxobj;
832 
833         VM_BUG_ON(!irqs_disabled());
834 
835         if (!PageSlab(page)) {
836                 slab_err(s, page, "Not a valid slab page");
837                 return 0;
838         }
839 
840         maxobj = order_objects(compound_order(page), s->size, s->reserved);
841         if (page->objects > maxobj) {
842                 slab_err(s, page, "objects %u > max %u",
843                         s->name, page->objects, maxobj);
844                 return 0;
845         }
846         if (page->inuse > page->objects) {
847                 slab_err(s, page, "inuse %u > max %u",
848                         s->name, page->inuse, page->objects);
849                 return 0;
850         }
851         /* Slab_pad_check fixes things up after itself */
852         slab_pad_check(s, page);
853         return 1;
854 }
855 
856 /*
857  * Determine if a certain object on a page is on the freelist. Must hold the
858  * slab lock to guarantee that the chains are in a consistent state.
859  */
860 static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
861 {
862         int nr = 0;
863         void *fp;
864         void *object = NULL;
865         unsigned long max_objects;
866 
867         fp = page->freelist;
868         while (fp && nr <= page->objects) {
869                 if (fp == search)
870                         return 1;
871                 if (!check_valid_pointer(s, page, fp)) {
872                         if (object) {
873                                 object_err(s, page, object,
874                                         "Freechain corrupt");
875                                 set_freepointer(s, object, NULL);
876                                 break;
877                         } else {
878                                 slab_err(s, page, "Freepointer corrupt");
879                                 page->freelist = NULL;
880                                 page->inuse = page->objects;
881                                 slab_fix(s, "Freelist cleared");
882                                 return 0;
883                         }
884                         break;
885                 }
886                 object = fp;
887                 fp = get_freepointer(s, object);
888                 nr++;
889         }
890 
891         max_objects = order_objects(compound_order(page), s->size, s->reserved);
892         if (max_objects > MAX_OBJS_PER_PAGE)
893                 max_objects = MAX_OBJS_PER_PAGE;
894 
895         if (page->objects != max_objects) {
896                 slab_err(s, page, "Wrong number of objects. Found %d but "
897                         "should be %d", page->objects, max_objects);
898                 page->objects = max_objects;
899                 slab_fix(s, "Number of objects adjusted.");
900         }
901         if (page->inuse != page->objects - nr) {
902                 slab_err(s, page, "Wrong object count. Counter is %d but "
903                         "counted were %d", page->inuse, page->objects - nr);
904                 page->inuse = page->objects - nr;
905                 slab_fix(s, "Object count adjusted.");
906         }
907         return search == NULL;
908 }
909 
910 static void trace(struct kmem_cache *s, struct page *page, void *object,
911                                                                 int alloc)
912 {
913         if (s->flags & SLAB_TRACE) {
914                 printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
915                         s->name,
916                         alloc ? "alloc" : "free",
917                         object, page->inuse,
918                         page->freelist);
919 
920                 if (!alloc)
921                         print_section("Object ", (void *)object, s->object_size);
922 
923                 dump_stack();
924         }
925 }
926 
927 /*
928  * Hooks for other subsystems that check memory allocations. In a typical
929  * production configuration these hooks all should produce no code at all.
930  */
931 static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
932 {
933         flags &= gfp_allowed_mask;
934         lockdep_trace_alloc(flags);
935         might_sleep_if(flags & __GFP_WAIT);
936 
937         return should_failslab(s->object_size, flags, s->flags);
938 }
939 
940 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
941 {
942         flags &= gfp_allowed_mask;
943         kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
944         kmemleak_alloc_recursive(object, s->object_size, 1, s->flags, flags);
945 }
946 
947 static inline void slab_free_hook(struct kmem_cache *s, void *x)
948 {
949         kmemleak_free_recursive(x, s->flags);
950 
951         /*
952          * Trouble is that we may no longer disable interupts in the fast path
953          * So in order to make the debug calls that expect irqs to be
954          * disabled we need to disable interrupts temporarily.
955          */
956 #if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
957         {
958                 unsigned long flags;
959 
960                 local_irq_save(flags);
961                 kmemcheck_slab_free(s, x, s->object_size);
962                 debug_check_no_locks_freed(x, s->object_size);
963                 local_irq_restore(flags);
964         }
965 #endif
966         if (!(s->flags & SLAB_DEBUG_OBJECTS))
967                 debug_check_no_obj_freed(x, s->object_size);
968 }
969 
970 /*
971  * Tracking of fully allocated slabs for debugging purposes.
972  *
973  * list_lock must be held.
974  */
975 static void add_full(struct kmem_cache *s,
976         struct kmem_cache_node *n, struct page *page)
977 {
978         if (!(s->flags & SLAB_STORE_USER))
979                 return;
980 
981         list_add(&page->lru, &n->full);
982 }
983 
984 /*
985  * list_lock must be held.
986  */
987 static void remove_full(struct kmem_cache *s, struct page *page)
988 {
989         if (!(s->flags & SLAB_STORE_USER))
990                 return;
991 
992         list_del(&page->lru);
993 }
994 
995 /* Tracking of the number of slabs for debugging purposes */
996 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
997 {
998         struct kmem_cache_node *n = get_node(s, node);
999 
1000         return atomic_long_read(&n->nr_slabs);
1001 }
1002 
1003 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1004 {
1005         return atomic_long_read(&n->nr_slabs);
1006 }
1007 
1008 static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1009 {
1010         struct kmem_cache_node *n = get_node(s, node);
1011 
1012         /*
1013          * May be called early in order to allocate a slab for the
1014          * kmem_cache_node structure. Solve the chicken-egg
1015          * dilemma by deferring the increment of the count during
1016          * bootstrap (see early_kmem_cache_node_alloc).
1017          */
1018         if (likely(n)) {
1019                 atomic_long_inc(&n->nr_slabs);
1020                 atomic_long_add(objects, &n->total_objects);
1021         }
1022 }
1023 static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1024 {
1025         struct kmem_cache_node *n = get_node(s, node);
1026 
1027         atomic_long_dec(&n->nr_slabs);
1028         atomic_long_sub(objects, &n->total_objects);
1029 }
1030 
1031 /* Object debug checks for alloc/free paths */
1032 static void setup_object_debug(struct kmem_cache *s, struct page *page,
1033                                                                 void *object)
1034 {
1035         if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1036                 return;
1037 
1038         init_object(s, object, SLUB_RED_INACTIVE);
1039         init_tracking(s, object);
1040 }
1041 
1042 static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
1043                                         void *object, unsigned long addr)
1044 {
1045         if (!check_slab(s, page))
1046                 goto bad;
1047 
1048         if (!check_valid_pointer(s, page, object)) {
1049                 object_err(s, page, object, "Freelist Pointer check fails");
1050                 goto bad;
1051         }
1052 
1053         if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1054                 goto bad;
1055 
1056         /* Success perform special debug activities for allocs */
1057         if (s->flags & SLAB_STORE_USER)
1058                 set_track(s, object, TRACK_ALLOC, addr);
1059         trace(s, page, object, 1);
1060         init_object(s, object, SLUB_RED_ACTIVE);
1061         return 1;
1062 
1063 bad:
1064         if (PageSlab(page)) {
1065                 /*
1066                  * If this is a slab page then lets do the best we can
1067                  * to avoid issues in the future. Marking all objects
1068                  * as used avoids touching the remaining objects.
1069                  */
1070                 slab_fix(s, "Marking all objects used");
1071                 page->inuse = page->objects;
1072                 page->freelist = NULL;
1073         }
1074         return 0;
1075 }
1076 
1077 static noinline struct kmem_cache_node *free_debug_processing(
1078         struct kmem_cache *s, struct page *page, void *object,
1079         unsigned long addr, unsigned long *flags)
1080 {
1081         struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1082 
1083         spin_lock_irqsave(&n->list_lock, *flags);
1084         slab_lock(page);
1085 
1086         if (!check_slab(s, page))
1087                 goto fail;
1088 
1089         if (!check_valid_pointer(s, page, object)) {
1090                 slab_err(s, page, "Invalid object pointer 0x%p", object);
1091                 goto fail;
1092         }
1093 
1094         if (on_freelist(s, page, object)) {
1095                 object_err(s, page, object, "Object already free");
1096                 goto fail;
1097         }
1098 
1099         if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1100                 goto out;
1101 
1102         if (unlikely(s != page->slab_cache)) {
1103                 if (!PageSlab(page)) {
1104                         slab_err(s, page, "Attempt to free object(0x%p) "
1105                                 "outside of slab", object);
1106                 } else if (!page->slab_cache) {
1107                         printk(KERN_ERR
1108                                 "SLUB <none>: no slab for object 0x%p.\n",
1109                                                 object);
1110                         dump_stack();
1111                 } else
1112                         object_err(s, page, object,
1113                                         "page slab pointer corrupt.");
1114                 goto fail;
1115         }
1116 
1117         if (s->flags & SLAB_STORE_USER)
1118                 set_track(s, object, TRACK_FREE, addr);
1119         trace(s, page, object, 0);
1120         init_object(s, object, SLUB_RED_INACTIVE);
1121 out:
1122         slab_unlock(page);
1123         /*
1124          * Keep node_lock to preserve integrity
1125          * until the object is actually freed
1126          */
1127         return n;
1128 
1129 fail:
1130         slab_unlock(page);
1131         spin_unlock_irqrestore(&n->list_lock, *flags);
1132         slab_fix(s, "Object at 0x%p not freed", object);
1133         return NULL;
1134 }
1135 
1136 static int __init setup_slub_debug(char *str)
1137 {
1138         slub_debug = DEBUG_DEFAULT_FLAGS;
1139         if (*str++ != '=' || !*str)
1140                 /*
1141                  * No options specified. Switch on full debugging.
1142                  */
1143                 goto out;
1144 
1145         if (*str == ',')
1146                 /*
1147                  * No options but restriction on slabs. This means full
1148                  * debugging for slabs matching a pattern.
1149                  */
1150                 goto check_slabs;
1151 
1152         if (tolower(*str) == 'o') {
1153                 /*
1154                  * Avoid enabling debugging on caches if its minimum order
1155                  * would increase as a result.
1156                  */
1157                 disable_higher_order_debug = 1;
1158                 goto out;
1159         }
1160 
1161         slub_debug = 0;
1162         if (*str == '-')
1163                 /*
1164                  * Switch off all debugging measures.
1165                  */
1166                 goto out;
1167 
1168         /*
1169          * Determine which debug features should be switched on
1170          */
1171         for (; *str && *str != ','; str++) {
1172                 switch (tolower(*str)) {
1173                 case 'f':
1174                         slub_debug |= SLAB_DEBUG_FREE;
1175                         break;
1176                 case 'z':
1177                         slub_debug |= SLAB_RED_ZONE;
1178                         break;
1179                 case 'p':
1180                         slub_debug |= SLAB_POISON;
1181                         break;
1182                 case 'u':
1183                         slub_debug |= SLAB_STORE_USER;
1184                         break;
1185                 case 't':
1186                         slub_debug |= SLAB_TRACE;
1187                         break;
1188                 case 'a':
1189                         slub_debug |= SLAB_FAILSLAB;
1190                         break;
1191                 default:
1192                         printk(KERN_ERR "slub_debug option '%c' "
1193                                 "unknown. skipped\n", *str);
1194                 }
1195         }
1196 
1197 check_slabs:
1198         if (*str == ',')
1199                 slub_debug_slabs = str + 1;
1200 out:
1201         return 1;
1202 }
1203 
1204 __setup("slub_debug", setup_slub_debug);
1205 
1206 static unsigned long kmem_cache_flags(unsigned long object_size,
1207         unsigned long flags, const char *name,
1208         void (*ctor)(void *))
1209 {
1210         /*
1211          * Enable debugging if selected on the kernel commandline.
1212          */
1213         if (slub_debug && (!slub_debug_slabs ||
1214                 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
1215                 flags |= slub_debug;
1216 
1217         return flags;
1218 }
1219 #else
1220 static inline void setup_object_debug(struct kmem_cache *s,
1221                         struct page *page, void *object) {}
1222 
1223 static inline int alloc_debug_processing(struct kmem_cache *s,
1224         struct page *page, void *object, unsigned long addr) { return 0; }
1225 
1226 static inline struct kmem_cache_node *free_debug_processing(
1227         struct kmem_cache *s, struct page *page, void *object,
1228         unsigned long addr, unsigned long *flags) { return NULL; }
1229 
1230 static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1231                         { return 1; }
1232 static inline int check_object(struct kmem_cache *s, struct page *page,
1233                         void *object, u8 val) { return 1; }
1234 static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1235                                         struct page *page) {}
1236 static inline void remove_full(struct kmem_cache *s, struct page *page) {}
1237 static inline unsigned long kmem_cache_flags(unsigned long object_size,
1238         unsigned long flags, const char *name,
1239         void (*ctor)(void *))
1240 {
1241         return flags;
1242 }
1243 #define slub_debug 0
1244 
1245 #define disable_higher_order_debug 0
1246 
1247 static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1248                                                         { return 0; }
1249 static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1250                                                         { return 0; }
1251 static inline void inc_slabs_node(struct kmem_cache *s, int node,
1252                                                         int objects) {}
1253 static inline void dec_slabs_node(struct kmem_cache *s, int node,
1254                                                         int objects) {}
1255 
1256 static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1257                                                         { return 0; }
1258 
1259 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
1260                 void *object) {}
1261 
1262 static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
1263 
1264 #endif /* CONFIG_SLUB_DEBUG */
1265 
1266 /*
1267  * Slab allocation and freeing
1268  */
1269 static inline struct page *alloc_slab_page(gfp_t flags, int node,
1270                                         struct kmem_cache_order_objects oo)
1271 {
1272         int order = oo_order(oo);
1273 
1274         flags |= __GFP_NOTRACK;
1275 
1276         if (node == NUMA_NO_NODE)
1277                 return alloc_pages(flags, order);
1278         else
1279                 return alloc_pages_exact_node(node, flags, order);
1280 }
1281 
1282 static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1283 {
1284         struct page *page;
1285         struct kmem_cache_order_objects oo = s->oo;
1286         gfp_t alloc_gfp;
1287 
1288         flags &= gfp_allowed_mask;
1289 
1290         if (flags & __GFP_WAIT)
1291                 local_irq_enable();
1292 
1293         flags |= s->allocflags;
1294 
1295         /*
1296          * Let the initial higher-order allocation fail under memory pressure
1297          * so we fall-back to the minimum order allocation.
1298          */
1299         alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1300 
1301         page = alloc_slab_page(alloc_gfp, node, oo);
1302         if (unlikely(!page)) {
1303                 oo = s->min;
1304                 /*
1305                  * Allocation may have failed due to fragmentation.
1306                  * Try a lower order alloc if possible
1307                  */
1308                 page = alloc_slab_page(flags, node, oo);
1309 
1310                 if (page)
1311                         stat(s, ORDER_FALLBACK);
1312         }
1313 
1314         if (kmemcheck_enabled && page
1315                 && !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1316                 int pages = 1 << oo_order(oo);
1317 
1318                 kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
1319 
1320                 /*
1321                  * Objects from caches that have a constructor don't get
1322                  * cleared when they're allocated, so we need to do it here.
1323                  */
1324                 if (s->ctor)
1325                         kmemcheck_mark_uninitialized_pages(page, pages);
1326                 else
1327                         kmemcheck_mark_unallocated_pages(page, pages);
1328         }
1329 
1330         if (flags & __GFP_WAIT)
1331                 local_irq_disable();
1332         if (!page)
1333                 return NULL;
1334 
1335         page->objects = oo_objects(oo);
1336         mod_zone_page_state(page_zone(page),
1337                 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1338                 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1339                 1 << oo_order(oo));
1340 
1341         return page;
1342 }
1343 
1344 static void setup_object(struct kmem_cache *s, struct page *page,
1345                                 void *object)
1346 {
1347         setup_object_debug(s, page, object);
1348         if (unlikely(s->ctor))
1349                 s->ctor(object);
1350 }
1351 
1352 static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1353 {
1354         struct page *page;
1355         void *start;
1356         void *last;
1357         void *p;
1358         int order;
1359 
1360         BUG_ON(flags & GFP_SLAB_BUG_MASK);
1361 
1362         page = allocate_slab(s,
1363                 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1364         if (!page)
1365                 goto out;
1366 
1367         order = compound_order(page);
1368         inc_slabs_node(s, page_to_nid(page), page->objects);
1369         memcg_bind_pages(s, order);
1370         page->slab_cache = s;
1371         __SetPageSlab(page);
1372         if (page->pfmemalloc)
1373                 SetPageSlabPfmemalloc(page);
1374 
1375         start = page_address(page);
1376 
1377         if (unlikely(s->flags & SLAB_POISON))
1378                 memset(start, POISON_INUSE, PAGE_SIZE << order);
1379 
1380         last = start;
1381         for_each_object(p, s, start, page->objects) {
1382                 setup_object(s, page, last);
1383                 set_freepointer(s, last, p);
1384                 last = p;
1385         }
1386         setup_object(s, page, last);
1387         set_freepointer(s, last, NULL);
1388 
1389         page->freelist = start;
1390         page->inuse = page->objects;
1391         page->frozen = 1;
1392 out:
1393         return page;
1394 }
1395 
1396 static void __free_slab(struct kmem_cache *s, struct page *page)
1397 {
1398         int order = compound_order(page);
1399         int pages = 1 << order;
1400 
1401         if (kmem_cache_debug(s)) {
1402                 void *p;
1403 
1404                 slab_pad_check(s, page);
1405                 for_each_object(p, s, page_address(page),
1406                                                 page->objects)
1407                         check_object(s, page, p, SLUB_RED_INACTIVE);
1408         }
1409 
1410         kmemcheck_free_shadow(page, compound_order(page));
1411 
1412         mod_zone_page_state(page_zone(page),
1413                 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1414                 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1415                 -pages);
1416 
1417         __ClearPageSlabPfmemalloc(page);
1418         __ClearPageSlab(page);
1419 
1420         memcg_release_pages(s, order);
1421         page_mapcount_reset(page);
1422         if (current->reclaim_state)
1423                 current->reclaim_state->reclaimed_slab += pages;
1424         __free_memcg_kmem_pages(page, order);
1425 }
1426 
1427 #define need_reserve_slab_rcu                                           \
1428         (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1429 
1430 static void rcu_free_slab(struct rcu_head *h)
1431 {
1432         struct page *page;
1433 
1434         if (need_reserve_slab_rcu)
1435                 page = virt_to_head_page(h);
1436         else
1437                 page = container_of((struct list_head *)h, struct page, lru);
1438 
1439         __free_slab(page->slab_cache, page);
1440 }
1441 
1442 static void free_slab(struct kmem_cache *s, struct page *page)
1443 {
1444         if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1445                 struct rcu_head *head;
1446 
1447                 if (need_reserve_slab_rcu) {
1448                         int order = compound_order(page);
1449                         int offset = (PAGE_SIZE << order) - s->reserved;
1450 
1451                         VM_BUG_ON(s->reserved != sizeof(*head));
1452                         head = page_address(page) + offset;
1453                 } else {
1454                         /*
1455                          * RCU free overloads the RCU head over the LRU
1456                          */
1457                         head = (void *)&page->lru;
1458                 }
1459 
1460                 call_rcu(head, rcu_free_slab);
1461         } else
1462                 __free_slab(s, page);
1463 }
1464 
1465 static void discard_slab(struct kmem_cache *s, struct page *page)
1466 {
1467         dec_slabs_node(s, page_to_nid(page), page->objects);
1468         free_slab(s, page);
1469 }
1470 
1471 /*
1472  * Management of partially allocated slabs.
1473  *
1474  * list_lock must be held.
1475  */
1476 static inline void add_partial(struct kmem_cache_node *n,
1477                                 struct page *page, int tail)
1478 {
1479         n->nr_partial++;
1480         if (tail == DEACTIVATE_TO_TAIL)
1481                 list_add_tail(&page->lru, &n->partial);
1482         else
1483                 list_add(&page->lru, &n->partial);
1484 }
1485 
1486 /*
1487  * list_lock must be held.
1488  */
1489 static inline void remove_partial(struct kmem_cache_node *n,
1490                                         struct page *page)
1491 {
1492         list_del(&page->lru);
1493         n->nr_partial--;
1494 }
1495 
1496 /*
1497  * Remove slab from the partial list, freeze it and
1498  * return the pointer to the freelist.
1499  *
1500  * Returns a list of objects or NULL if it fails.
1501  *
1502  * Must hold list_lock since we modify the partial list.
1503  */
1504 static inline void *acquire_slab(struct kmem_cache *s,
1505                 struct kmem_cache_node *n, struct page *page,
1506                 int mode, int *objects)
1507 {
1508         void *freelist;
1509         unsigned long counters;
1510         struct page new;
1511 
1512         /*
1513          * Zap the freelist and set the frozen bit.
1514          * The old freelist is the list of objects for the
1515          * per cpu allocation list.
1516          */
1517         freelist = page->freelist;
1518         counters = page->counters;
1519         new.counters = counters;
1520         *objects = new.objects - new.inuse;
1521         if (mode) {
1522                 new.inuse = page->objects;
1523                 new.freelist = NULL;
1524         } else {
1525                 new.freelist = freelist;
1526         }
1527 
1528         VM_BUG_ON(new.frozen);
1529         new.frozen = 1;
1530 
1531         if (!__cmpxchg_double_slab(s, page,
1532                         freelist, counters,
1533                         new.freelist, new.counters,
1534                         "acquire_slab"))
1535                 return NULL;
1536 
1537         remove_partial(n, page);
1538         WARN_ON(!freelist);
1539         return freelist;
1540 }
1541 
1542 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1543 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1544 
1545 /*
1546  * Try to allocate a partial slab from a specific node.
1547  */
1548 static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1549                                 struct kmem_cache_cpu *c, gfp_t flags)
1550 {
1551         struct page *page, *page2;
1552         void *object = NULL;
1553         int available = 0;
1554         int objects;
1555 
1556         /*
1557          * Racy check. If we mistakenly see no partial slabs then we
1558          * just allocate an empty slab. If we mistakenly try to get a
1559          * partial slab and there is none available then get_partials()
1560          * will return NULL.
1561          */
1562         if (!n || !n->nr_partial)
1563                 return NULL;
1564 
1565         spin_lock(&n->list_lock);
1566         list_for_each_entry_safe(page, page2, &n->partial, lru) {
1567                 void *t;
1568 
1569                 if (!pfmemalloc_match(page, flags))
1570                         continue;
1571 
1572                 t = acquire_slab(s, n, page, object == NULL, &objects);
1573                 if (!t)
1574                         break;
1575 
1576                 available += objects;
1577                 if (!object) {
1578                         c->page = page;
1579                         stat(s, ALLOC_FROM_PARTIAL);
1580                         object = t;
1581                 } else {
1582                         put_cpu_partial(s, page, 0);
1583                         stat(s, CPU_PARTIAL_NODE);
1584                 }
1585                 if (!kmem_cache_has_cpu_partial(s)
1586                         || available > s->cpu_partial / 2)
1587                         break;
1588 
1589         }
1590         spin_unlock(&n->list_lock);
1591         return object;
1592 }
1593 
1594 /*
1595  * Get a page from somewhere. Search in increasing NUMA distances.
1596  */
1597 static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1598                 struct kmem_cache_cpu *c)
1599 {
1600 #ifdef CONFIG_NUMA
1601         struct zonelist *zonelist;
1602         struct zoneref *z;
1603         struct zone *zone;
1604         enum zone_type high_zoneidx = gfp_zone(flags);
1605         void *object;
1606         unsigned int cpuset_mems_cookie;
1607 
1608         /*
1609          * The defrag ratio allows a configuration of the tradeoffs between
1610          * inter node defragmentation and node local allocations. A lower
1611          * defrag_ratio increases the tendency to do local allocations
1612          * instead of attempting to obtain partial slabs from other nodes.
1613          *
1614          * If the defrag_ratio is set to 0 then kmalloc() always
1615          * returns node local objects. If the ratio is higher then kmalloc()
1616          * may return off node objects because partial slabs are obtained
1617          * from other nodes and filled up.
1618          *
1619          * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1620          * defrag_ratio = 1000) then every (well almost) allocation will
1621          * first attempt to defrag slab caches on other nodes. This means
1622          * scanning over all nodes to look for partial slabs which may be
1623          * expensive if we do it every time we are trying to find a slab
1624          * with available objects.
1625          */
1626         if (!s->remote_node_defrag_ratio ||
1627                         get_cycles() % 1024 > s->remote_node_defrag_ratio)
1628                 return NULL;
1629 
1630         do {
1631                 cpuset_mems_cookie = get_mems_allowed();
1632                 zonelist = node_zonelist(slab_node(), flags);
1633                 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1634                         struct kmem_cache_node *n;
1635 
1636                         n = get_node(s, zone_to_nid(zone));
1637 
1638                         if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1639                                         n->nr_partial > s->min_partial) {
1640                                 object = get_partial_node(s, n, c, flags);
1641                                 if (object) {
1642                                         /*
1643                                          * Return the object even if
1644                                          * put_mems_allowed indicated that
1645                                          * the cpuset mems_allowed was
1646                                          * updated in parallel. It's a
1647                                          * harmless race between the alloc
1648                                          * and the cpuset update.
1649                                          */
1650                                         put_mems_allowed(cpuset_mems_cookie);
1651                                         return object;
1652                                 }
1653                         }
1654                 }
1655         } while (!put_mems_allowed(cpuset_mems_cookie));
1656 #endif
1657         return NULL;
1658 }
1659 
1660 /*
1661  * Get a partial page, lock it and return it.
1662  */
1663 static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1664                 struct kmem_cache_cpu *c)
1665 {
1666         void *object;
1667         int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
1668 
1669         object = get_partial_node(s, get_node(s, searchnode), c, flags);
1670         if (object || node != NUMA_NO_NODE)
1671                 return object;
1672 
1673         return get_any_partial(s, flags, c);
1674 }
1675 
1676 #ifdef CONFIG_PREEMPT
1677 /*
1678  * Calculate the next globally unique transaction for disambiguiation
1679  * during cmpxchg. The transactions start with the cpu number and are then
1680  * incremented by CONFIG_NR_CPUS.
1681  */
1682 #define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
1683 #else
1684 /*
1685  * No preemption supported therefore also no need to check for
1686  * different cpus.
1687  */
1688 #define TID_STEP 1
1689 #endif
1690 
1691 static inline unsigned long next_tid(unsigned long tid)
1692 {
1693         return tid + TID_STEP;
1694 }
1695 
1696 static inline unsigned int tid_to_cpu(unsigned long tid)
1697 {
1698         return tid % TID_STEP;
1699 }
1700 
1701 static inline unsigned long tid_to_event(unsigned long tid)
1702 {
1703         return tid / TID_STEP;
1704 }
1705 
1706 static inline unsigned int init_tid(int cpu)
1707 {
1708         return cpu;
1709 }
1710 
1711 static inline void note_cmpxchg_failure(const char *n,
1712                 const struct kmem_cache *s, unsigned long tid)
1713 {
1714 #ifdef SLUB_DEBUG_CMPXCHG
1715         unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1716 
1717         printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
1718 
1719 #ifdef CONFIG_PREEMPT
1720         if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1721                 printk("due to cpu change %d -> %d\n",
1722                         tid_to_cpu(tid), tid_to_cpu(actual_tid));
1723         else
1724 #endif
1725         if (tid_to_event(tid) != tid_to_event(actual_tid))
1726                 printk("due to cpu running other code. Event %ld->%ld\n",
1727                         tid_to_event(tid), tid_to_event(actual_tid));
1728         else
1729                 printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1730                         actual_tid, tid, next_tid(tid));
1731 #endif
1732         stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1733 }
1734 
1735 static void init_kmem_cache_cpus(struct kmem_cache *s)
1736 {
1737         int cpu;
1738 
1739         for_each_possible_cpu(cpu)
1740                 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
1741 }
1742 
1743 /*
1744  * Remove the cpu slab
1745  */
1746 static void deactivate_slab(struct kmem_cache *s, struct page *page, void *freelist)
1747 {
1748         enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1749         struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1750         int lock = 0;
1751         enum slab_modes l = M_NONE, m = M_NONE;
1752         void *nextfree;
1753         int tail = DEACTIVATE_TO_HEAD;
1754         struct page new;
1755         struct page old;
1756 
1757         if (page->freelist) {
1758                 stat(s, DEACTIVATE_REMOTE_FREES);
1759                 tail = DEACTIVATE_TO_TAIL;
1760         }
1761 
1762         /*
1763          * Stage one: Free all available per cpu objects back
1764          * to the page freelist while it is still frozen. Leave the
1765          * last one.
1766          *
1767          * There is no need to take the list->lock because the page
1768          * is still frozen.
1769          */
1770         while (freelist && (nextfree = get_freepointer(s, freelist))) {
1771                 void *prior;
1772                 unsigned long counters;
1773 
1774                 do {
1775                         prior = page->freelist;
1776                         counters = page->counters;
1777                         set_freepointer(s, freelist, prior);
1778                         new.counters = counters;
1779                         new.inuse--;
1780                         VM_BUG_ON(!new.frozen);
1781 
1782                 } while (!__cmpxchg_double_slab(s, page,
1783                         prior, counters,
1784                         freelist, new.counters,
1785                         "drain percpu freelist"));
1786 
1787                 freelist = nextfree;
1788         }
1789 
1790         /*
1791          * Stage two: Ensure that the page is unfrozen while the
1792          * list presence reflects the actual number of objects
1793          * during unfreeze.
1794          *
1795          * We setup the list membership and then perform a cmpxchg
1796          * with the count. If there is a mismatch then the page
1797          * is not unfrozen but the page is on the wrong list.
1798          *
1799          * Then we restart the process which may have to remove
1800          * the page from the list that we just put it on again
1801          * because the number of objects in the slab may have
1802          * changed.
1803          */
1804 redo:
1805 
1806         old.freelist = page->freelist;
1807         old.counters = page->counters;
1808         VM_BUG_ON(!old.frozen);
1809 
1810         /* Determine target state of the slab */
1811         new.counters = old.counters;
1812         if (freelist) {
1813                 new.inuse--;
1814                 set_freepointer(s, freelist, old.freelist);
1815                 new.freelist = freelist;
1816         } else
1817                 new.freelist = old.freelist;
1818 
1819         new.frozen = 0;
1820 
1821         if (!new.inuse && n->nr_partial > s->min_partial)
1822                 m = M_FREE;
1823         else if (new.freelist) {
1824                 m = M_PARTIAL;
1825                 if (!lock) {
1826                         lock = 1;
1827                         /*
1828                          * Taking the spinlock removes the possiblity
1829                          * that acquire_slab() will see a slab page that
1830                          * is frozen
1831                          */
1832                         spin_lock(&n->list_lock);
1833                 }
1834         } else {
1835                 m = M_FULL;
1836                 if (kmem_cache_debug(s) && !lock) {
1837                         lock = 1;
1838                         /*
1839                          * This also ensures that the scanning of full
1840                          * slabs from diagnostic functions will not see
1841                          * any frozen slabs.
1842                          */
1843                         spin_lock(&n->list_lock);
1844                 }
1845         }
1846 
1847         if (l != m) {
1848 
1849                 if (l == M_PARTIAL)
1850 
1851                         remove_partial(n, page);
1852 
1853                 else if (l == M_FULL)
1854 
1855                         remove_full(s, page);
1856 
1857                 if (m == M_PARTIAL) {
1858 
1859                         add_partial(n, page, tail);
1860                         stat(s, tail);
1861 
1862                 } else if (m == M_FULL) {
1863 
1864                         stat(s, DEACTIVATE_FULL);
1865                         add_full(s, n, page);
1866 
1867                 }
1868         }
1869 
1870         l = m;
1871         if (!__cmpxchg_double_slab(s, page,
1872                                 old.freelist, old.counters,
1873                                 new.freelist, new.counters,
1874                                 "unfreezing slab"))
1875                 goto redo;
1876 
1877         if (lock)
1878                 spin_unlock(&n->list_lock);
1879 
1880         if (m == M_FREE) {
1881                 stat(s, DEACTIVATE_EMPTY);
1882                 discard_slab(s, page);
1883                 stat(s, FREE_SLAB);
1884         }
1885 }
1886 
1887 /*
1888  * Unfreeze all the cpu partial slabs.
1889  *
1890  * This function must be called with interrupts disabled
1891  * for the cpu using c (or some other guarantee must be there
1892  * to guarantee no concurrent accesses).
1893  */
1894 static void unfreeze_partials(struct kmem_cache *s,
1895                 struct kmem_cache_cpu *c)
1896 {
1897 #ifdef CONFIG_SLUB_CPU_PARTIAL
1898         struct kmem_cache_node *n = NULL, *n2 = NULL;
1899         struct page *page, *discard_page = NULL;
1900 
1901         while ((page = c->partial)) {
1902                 struct page new;
1903                 struct page old;
1904 
1905                 c->partial = page->next;
1906 
1907                 n2 = get_node(s, page_to_nid(page));
1908                 if (n != n2) {
1909                         if (n)
1910                                 spin_unlock(&n->list_lock);
1911 
1912                         n = n2;
1913                         spin_lock(&n->list_lock);
1914                 }
1915 
1916                 do {
1917 
1918                         old.freelist = page->freelist;
1919                         old.counters = page->counters;
1920                         VM_BUG_ON(!old.frozen);
1921 
1922                         new.counters = old.counters;
1923                         new.freelist = old.freelist;
1924 
1925                         new.frozen = 0;
1926 
1927                 } while (!__cmpxchg_double_slab(s, page,
1928                                 old.freelist, old.counters,
1929                                 new.freelist, new.counters,
1930                                 "unfreezing slab"));
1931 
1932                 if (unlikely(!new.inuse && n->nr_partial > s->min_partial)) {
1933                         page->next = discard_page;
1934                         discard_page = page;
1935                 } else {
1936                         add_partial(n, page, DEACTIVATE_TO_TAIL);
1937                         stat(s, FREE_ADD_PARTIAL);
1938                 }
1939         }
1940 
1941         if (n)
1942                 spin_unlock(&n->list_lock);
1943 
1944         while (discard_page) {
1945                 page = discard_page;
1946                 discard_page = discard_page->next;
1947 
1948                 stat(s, DEACTIVATE_EMPTY);
1949                 discard_slab(s, page);
1950                 stat(s, FREE_SLAB);
1951         }
1952 #endif
1953 }
1954 
1955 /*
1956  * Put a page that was just frozen (in __slab_free) into a partial page
1957  * slot if available. This is done without interrupts disabled and without
1958  * preemption disabled. The cmpxchg is racy and may put the partial page
1959  * onto a random cpus partial slot.
1960  *
1961  * If we did not find a slot then simply move all the partials to the
1962  * per node partial list.
1963  */
1964 static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
1965 {
1966 #ifdef CONFIG_SLUB_CPU_PARTIAL
1967         struct page *oldpage;
1968         int pages;
1969         int pobjects;
1970 
1971         do {
1972                 pages = 0;
1973                 pobjects = 0;
1974                 oldpage = this_cpu_read(s->cpu_slab->partial);
1975 
1976                 if (oldpage) {
1977                         pobjects = oldpage->pobjects;
1978                         pages = oldpage->pages;
1979                         if (drain && pobjects > s->cpu_partial) {
1980                                 unsigned long flags;
1981                                 /*
1982                                  * partial array is full. Move the existing
1983                                  * set to the per node partial list.
1984                                  */
1985                                 local_irq_save(flags);
1986                                 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
1987                                 local_irq_restore(flags);
1988                                 oldpage = NULL;
1989                                 pobjects = 0;
1990                                 pages = 0;
1991                                 stat(s, CPU_PARTIAL_DRAIN);
1992                         }
1993                 }
1994 
1995                 pages++;
1996                 pobjects += page->objects - page->inuse;
1997 
1998                 page->pages = pages;
1999                 page->pobjects = pobjects;
2000                 page->next = oldpage;
2001 
2002         } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
2003 #endif
2004 }
2005 
2006 static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2007 {
2008         stat(s, CPUSLAB_FLUSH);
2009         deactivate_slab(s, c->page, c->freelist);
2010 
2011         c->tid = next_tid(c->tid);
2012         c->page = NULL;
2013         c->freelist = NULL;
2014 }
2015 
2016 /*
2017  * Flush cpu slab.
2018  *
2019  * Called from IPI handler with interrupts disabled.
2020  */
2021 static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2022 {
2023         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2024 
2025         if (likely(c)) {
2026                 if (c->page)
2027                         flush_slab(s, c);
2028 
2029                 unfreeze_partials(s, c);
2030         }
2031 }
2032 
2033 static void flush_cpu_slab(void *d)
2034 {
2035         struct kmem_cache *s = d;
2036 
2037         __flush_cpu_slab(s, smp_processor_id());
2038 }
2039 
2040 static bool has_cpu_slab(int cpu, void *info)
2041 {
2042         struct kmem_cache *s = info;
2043         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2044 
2045         return c->page || c->partial;
2046 }
2047 
2048 static void flush_all(struct kmem_cache *s)
2049 {
2050         on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2051 }
2052 
2053 /*
2054  * Check if the objects in a per cpu structure fit numa
2055  * locality expectations.
2056  */
2057 static inline int node_match(struct page *page, int node)
2058 {
2059 #ifdef CONFIG_NUMA
2060         if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2061                 return 0;
2062 #endif
2063         return 1;
2064 }
2065 
2066 static int count_free(struct page *page)
2067 {
2068         return page->objects - page->inuse;
2069 }
2070 
2071 static unsigned long count_partial(struct kmem_cache_node *n,
2072                                         int (*get_count)(struct page *))
2073 {
2074         unsigned long flags;
2075         unsigned long x = 0;
2076         struct page *page;
2077 
2078         spin_lock_irqsave(&n->list_lock, flags);
2079         list_for_each_entry(page, &n->partial, lru)
2080                 x += get_count(page);
2081         spin_unlock_irqrestore(&n->list_lock, flags);
2082         return x;
2083 }
2084 
2085 static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2086 {
2087 #ifdef CONFIG_SLUB_DEBUG
2088         return atomic_long_read(&n->total_objects);
2089 #else
2090         return 0;
2091 #endif
2092 }
2093 
2094 static noinline void
2095 slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2096 {
2097         int node;
2098 
2099         printk(KERN_WARNING
2100                 "SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2101                 nid, gfpflags);
2102         printk(KERN_WARNING "  cache: %s, object size: %d, buffer size: %d, "
2103                 "default order: %d, min order: %d\n", s->name, s->object_size,
2104                 s->size, oo_order(s->oo), oo_order(s->min));
2105 
2106         if (oo_order(s->min) > get_order(s->object_size))
2107                 printk(KERN_WARNING "  %s debugging increased min order, use "
2108                        "slub_debug=O to disable.\n", s->name);
2109 
2110         for_each_online_node(node) {
2111                 struct kmem_cache_node *n = get_node(s, node);
2112                 unsigned long nr_slabs;
2113                 unsigned long nr_objs;
2114                 unsigned long nr_free;
2115 
2116                 if (!n)
2117                         continue;
2118 
2119                 nr_free  = count_partial(n, count_free);
2120                 nr_slabs = node_nr_slabs(n);
2121                 nr_objs  = node_nr_objs(n);
2122 
2123                 printk(KERN_WARNING
2124                         "  node %d: slabs: %ld, objs: %ld, free: %ld\n",
2125                         node, nr_slabs, nr_objs, nr_free);
2126         }
2127 }
2128 
2129 static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2130                         int node, struct kmem_cache_cpu **pc)
2131 {
2132         void *freelist;
2133         struct kmem_cache_cpu *c = *pc;
2134         struct page *page;
2135 
2136         freelist = get_partial(s, flags, node, c);
2137 
2138         if (freelist)
2139                 return freelist;
2140 
2141         page = new_slab(s, flags, node);
2142         if (page) {
2143                 c = __this_cpu_ptr(s->cpu_slab);
2144                 if (c->page)
2145                         flush_slab(s, c);
2146 
2147                 /*
2148                  * No other reference to the page yet so we can
2149                  * muck around with it freely without cmpxchg
2150                  */
2151                 freelist = page->freelist;
2152                 page->freelist = NULL;
2153 
2154                 stat(s, ALLOC_SLAB);
2155                 c->page = page;
2156                 *pc = c;
2157         } else
2158                 freelist = NULL;
2159 
2160         return freelist;
2161 }
2162 
2163 static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2164 {
2165         if (unlikely(PageSlabPfmemalloc(page)))
2166                 return gfp_pfmemalloc_allowed(gfpflags);
2167 
2168         return true;
2169 }
2170 
2171 /*
2172  * Check the page->freelist of a page and either transfer the freelist to the per cpu freelist
2173  * or deactivate the page.
2174  *
2175  * The page is still frozen if the return value is not NULL.
2176  *
2177  * If this function returns NULL then the page has been unfrozen.
2178  *
2179  * This function must be called with interrupt disabled.
2180  */
2181 static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2182 {
2183         struct page new;
2184         unsigned long counters;
2185         void *freelist;
2186 
2187         do {
2188                 freelist = page->freelist;
2189                 counters = page->counters;
2190 
2191                 new.counters = counters;
2192                 VM_BUG_ON(!new.frozen);
2193 
2194                 new.inuse = page->objects;
2195                 new.frozen = freelist != NULL;
2196 
2197         } while (!__cmpxchg_double_slab(s, page,
2198                 freelist, counters,
2199                 NULL, new.counters,
2200                 "get_freelist"));
2201 
2202         return freelist;
2203 }
2204 
2205 /*
2206  * Slow path. The lockless freelist is empty or we need to perform
2207  * debugging duties.
2208  *
2209  * Processing is still very fast if new objects have been freed to the
2210  * regular freelist. In that case we simply take over the regular freelist
2211  * as the lockless freelist and zap the regular freelist.
2212  *
2213  * If that is not working then we fall back to the partial lists. We take the
2214  * first element of the freelist as the object to allocate now and move the
2215  * rest of the freelist to the lockless freelist.
2216  *
2217  * And if we were unable to get a new slab from the partial slab lists then
2218  * we need to allocate a new slab. This is the slowest path since it involves
2219  * a call to the page allocator and the setup of a new slab.
2220  */
2221 static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2222                           unsigned long addr, struct kmem_cache_cpu *c)
2223 {
2224         void *freelist;
2225         struct page *page;
2226         unsigned long flags;
2227 
2228         local_irq_save(flags);
2229 #ifdef CONFIG_PREEMPT
2230         /*
2231          * We may have been preempted and rescheduled on a different
2232          * cpu before disabling interrupts. Need to reload cpu area
2233          * pointer.
2234          */
2235         c = this_cpu_ptr(s->cpu_slab);
2236 #endif
2237 
2238         page = c->page;
2239         if (!page)
2240                 goto new_slab;
2241 redo:
2242 
2243         if (unlikely(!node_match(page, node))) {
2244                 stat(s, ALLOC_NODE_MISMATCH);
2245                 deactivate_slab(s, page, c->freelist);
2246                 c->page = NULL;
2247                 c->freelist = NULL;
2248                 goto new_slab;
2249         }
2250 
2251         /*
2252          * By rights, we should be searching for a slab page that was
2253          * PFMEMALLOC but right now, we are losing the pfmemalloc
2254          * information when the page leaves the per-cpu allocator
2255          */
2256         if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2257                 deactivate_slab(s, page, c->freelist);
2258                 c->page = NULL;
2259                 c->freelist = NULL;
2260                 goto new_slab;
2261         }
2262 
2263         /* must check again c->freelist in case of cpu migration or IRQ */
2264         freelist = c->freelist;
2265         if (freelist)
2266                 goto load_freelist;
2267 
2268         stat(s, ALLOC_SLOWPATH);
2269 
2270         freelist = get_freelist(s, page);
2271 
2272         if (!freelist) {
2273                 c->page = NULL;
2274                 stat(s, DEACTIVATE_BYPASS);
2275                 goto new_slab;
2276         }
2277 
2278         stat(s, ALLOC_REFILL);
2279 
2280 load_freelist:
2281         /*
2282          * freelist is pointing to the list of objects to be used.
2283          * page is pointing to the page from which the objects are obtained.
2284          * That page must be frozen for per cpu allocations to work.
2285          */
2286         VM_BUG_ON(!c->page->frozen);
2287         c->freelist = get_freepointer(s, freelist);
2288         c->tid = next_tid(c->tid);
2289         local_irq_restore(flags);
2290         return freelist;
2291 
2292 new_slab:
2293 
2294         if (c->partial) {
2295                 page = c->page = c->partial;
2296                 c->partial = page->next;
2297                 stat(s, CPU_PARTIAL_ALLOC);
2298                 c->freelist = NULL;
2299                 goto redo;
2300         }
2301 
2302         freelist = new_slab_objects(s, gfpflags, node, &c);
2303 
2304         if (unlikely(!freelist)) {
2305                 if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
2306                         slab_out_of_memory(s, gfpflags, node);
2307 
2308                 local_irq_restore(flags);
2309                 return NULL;
2310         }
2311 
2312         page = c->page;
2313         if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2314                 goto load_freelist;
2315 
2316         /* Only entered in the debug case */
2317         if (kmem_cache_debug(s) && !alloc_debug_processing(s, page, freelist, addr))
2318                 goto new_slab;  /* Slab failed checks. Next slab needed */
2319 
2320         deactivate_slab(s, page, get_freepointer(s, freelist));
2321         c->page = NULL;
2322         c->freelist = NULL;
2323         local_irq_restore(flags);
2324         return freelist;
2325 }
2326 
2327 /*
2328  * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2329  * have the fastpath folded into their functions. So no function call
2330  * overhead for requests that can be satisfied on the fastpath.
2331  *
2332  * The fastpath works by first checking if the lockless freelist can be used.
2333  * If not then __slab_alloc is called for slow processing.
2334  *
2335  * Otherwise we can simply pick the next object from the lockless free list.
2336  */
2337 static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2338                 gfp_t gfpflags, int node, unsigned long addr)
2339 {
2340         void **object;
2341         struct kmem_cache_cpu *c;
2342         struct page *page;
2343         unsigned long tid;
2344 
2345         if (slab_pre_alloc_hook(s, gfpflags))
2346                 return NULL;
2347 
2348         s = memcg_kmem_get_cache(s, gfpflags);
2349 redo:
2350         /*
2351          * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2352          * enabled. We may switch back and forth between cpus while
2353          * reading from one cpu area. That does not matter as long
2354          * as we end up on the original cpu again when doing the cmpxchg.
2355          *
2356          * Preemption is disabled for the retrieval of the tid because that
2357          * must occur from the current processor. We cannot allow rescheduling
2358          * on a different processor between the determination of the pointer
2359          * and the retrieval of the tid.
2360          */
2361         preempt_disable();
2362         c = __this_cpu_ptr(s->cpu_slab);
2363 
2364         /*
2365          * The transaction ids are globally unique per cpu and per operation on
2366          * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2367          * occurs on the right processor and that there was no operation on the
2368          * linked list in between.
2369          */
2370         tid = c->tid;
2371         preempt_enable();
2372 
2373         object = c->freelist;
2374         page = c->page;
2375         if (unlikely(!object || !page || !node_match(page, node)))
2376                 object = __slab_alloc(s, gfpflags, node, addr, c);
2377 
2378         else {
2379                 void *next_object = get_freepointer_safe(s, object);
2380 
2381                 /*
2382                  * The cmpxchg will only match if there was no additional
2383                  * operation and if we are on the right processor.
2384                  *
2385                  * The cmpxchg does the following atomically (without lock semantics!)
2386                  * 1. Relocate first pointer to the current per cpu area.
2387                  * 2. Verify that tid and freelist have not been changed
2388                  * 3. If they were not changed replace tid and freelist
2389                  *
2390                  * Since this is without lock semantics the protection is only against
2391                  * code executing on this cpu *not* from access by other cpus.
2392                  */
2393                 if (unlikely(!this_cpu_cmpxchg_double(
2394                                 s->cpu_slab->freelist, s->cpu_slab->tid,
2395                                 object, tid,
2396                                 next_object, next_tid(tid)))) {
2397 
2398                         note_cmpxchg_failure("slab_alloc", s, tid);
2399                         goto redo;
2400                 }
2401                 prefetch_freepointer(s, next_object);
2402                 stat(s, ALLOC_FASTPATH);
2403         }
2404 
2405         if (unlikely(gfpflags & __GFP_ZERO) && object)
2406                 memset(object, 0, s->object_size);
2407 
2408         slab_post_alloc_hook(s, gfpflags, object);
2409 
2410         return object;
2411 }
2412 
2413 static __always_inline void *slab_alloc(struct kmem_cache *s,
2414                 gfp_t gfpflags, unsigned long addr)
2415 {
2416         return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2417 }
2418 
2419 void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2420 {
2421         void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2422 
2423         trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size, s->size, gfpflags);
2424 
2425         return ret;
2426 }
2427 EXPORT_SYMBOL(kmem_cache_alloc);
2428 
2429 #ifdef CONFIG_TRACING
2430 void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2431 {
2432         void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2433         trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2434         return ret;
2435 }
2436 EXPORT_SYMBOL(kmem_cache_alloc_trace);
2437 
2438 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
2439 {
2440         void *ret = kmalloc_order(size, flags, order);
2441         trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
2442         return ret;
2443 }
2444 EXPORT_SYMBOL(kmalloc_order_trace);
2445 #endif
2446 
2447 #ifdef CONFIG_NUMA
2448 void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2449 {
2450         void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2451 
2452         trace_kmem_cache_alloc_node(_RET_IP_, ret,
2453                                     s->object_size, s->size, gfpflags, node);
2454 
2455         return ret;
2456 }
2457 EXPORT_SYMBOL(kmem_cache_alloc_node);
2458 
2459 #ifdef CONFIG_TRACING
2460 void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2461                                     gfp_t gfpflags,
2462                                     int node, size_t size)
2463 {
2464         void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2465 
2466         trace_kmalloc_node(_RET_IP_, ret,
2467                            size, s->size, gfpflags, node);
2468         return ret;
2469 }
2470 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2471 #endif
2472 #endif
2473 
2474 /*
2475  * Slow patch handling. This may still be called frequently since objects
2476  * have a longer lifetime than the cpu slabs in most processing loads.
2477  *
2478  * So we still attempt to reduce cache line usage. Just take the slab
2479  * lock and free the item. If there is no additional partial page
2480  * handling required then we can return immediately.
2481  */
2482 static void __slab_free(struct kmem_cache *s, struct page *page,
2483                         void *x, unsigned long addr)
2484 {
2485         void *prior;
2486         void **object = (void *)x;
2487         int was_frozen;
2488         struct page new;
2489         unsigned long counters;
2490         struct kmem_cache_node *n = NULL;
2491         unsigned long uninitialized_var(flags);
2492 
2493         stat(s, FREE_SLOWPATH);
2494 
2495         if (kmem_cache_debug(s) &&
2496                 !(n = free_debug_processing(s, page, x, addr, &flags)))
2497                 return;
2498 
2499         do {
2500                 if (unlikely(n)) {
2501                         spin_unlock_irqrestore(&n->list_lock, flags);
2502                         n = NULL;
2503                 }
2504                 prior = page->freelist;
2505                 counters = page->counters;
2506                 set_freepointer(s, object, prior);
2507                 new.counters = counters;
2508                 was_frozen = new.frozen;
2509                 new.inuse--;
2510                 if ((!new.inuse || !prior) && !was_frozen) {
2511 
2512                         if (kmem_cache_has_cpu_partial(s) && !prior)
2513 
2514                                 /*
2515                                  * Slab was on no list before and will be partially empty
2516                                  * We can defer the list move and instead freeze it.
2517                                  */
2518                                 new.frozen = 1;
2519 
2520                         else { /* Needs to be taken off a list */
2521 
2522                                 n = get_node(s, page_to_nid(page));
2523                                 /*
2524                                  * Speculatively acquire the list_lock.
2525                                  * If the cmpxchg does not succeed then we may
2526                                  * drop the list_lock without any processing.
2527                                  *
2528                                  * Otherwise the list_lock will synchronize with
2529                                  * other processors updating the list of slabs.
2530                                  */
2531                                 spin_lock_irqsave(&n->list_lock, flags);
2532 
2533                         }
2534                 }
2535 
2536         } while (!cmpxchg_double_slab(s, page,
2537                 prior, counters,
2538                 object, new.counters,
2539                 "__slab_free"));
2540 
2541         if (likely(!n)) {
2542 
2543                 /*
2544                  * If we just froze the page then put it onto the
2545                  * per cpu partial list.
2546                  */
2547                 if (new.frozen && !was_frozen) {
2548                         put_cpu_partial(s, page, 1);
2549                         stat(s, CPU_PARTIAL_FREE);
2550                 }
2551                 /*
2552                  * The list lock was not taken therefore no list
2553                  * activity can be necessary.
2554                  */
2555                 if (was_frozen)
2556                         stat(s, FREE_FROZEN);
2557                 return;
2558         }
2559 
2560         if (unlikely(!new.inuse && n->nr_partial > s->min_partial))
2561                 goto slab_empty;
2562 
2563         /*
2564          * Objects left in the slab. If it was not on the partial list before
2565          * then add it.
2566          */
2567         if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2568                 if (kmem_cache_debug(s))
2569                         remove_full(s, page);
2570                 add_partial(n, page, DEACTIVATE_TO_TAIL);
2571                 stat(s, FREE_ADD_PARTIAL);
2572         }
2573         spin_unlock_irqrestore(&n->list_lock, flags);
2574         return;
2575 
2576 slab_empty:
2577         if (prior) {
2578                 /*
2579                  * Slab on the partial list.
2580                  */
2581                 remove_partial(n, page);
2582                 stat(s, FREE_REMOVE_PARTIAL);
2583         } else
2584                 /* Slab must be on the full list */
2585                 remove_full(s, page);
2586 
2587         spin_unlock_irqrestore(&n->list_lock, flags);
2588         stat(s, FREE_SLAB);
2589         discard_slab(s, page);
2590 }
2591 
2592 /*
2593  * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2594  * can perform fastpath freeing without additional function calls.
2595  *
2596  * The fastpath is only possible if we are freeing to the current cpu slab
2597  * of this processor. This typically the case if we have just allocated
2598  * the item before.
2599  *
2600  * If fastpath is not possible then fall back to __slab_free where we deal
2601  * with all sorts of special processing.
2602  */
2603 static __always_inline void slab_free(struct kmem_cache *s,
2604                         struct page *page, void *x, unsigned long addr)
2605 {
2606         void **object = (void *)x;
2607         struct kmem_cache_cpu *c;
2608         unsigned long tid;
2609 
2610         slab_free_hook(s, x);
2611 
2612 redo:
2613         /*
2614          * Determine the currently cpus per cpu slab.
2615          * The cpu may change afterward. However that does not matter since
2616          * data is retrieved via this pointer. If we are on the same cpu
2617          * during the cmpxchg then the free will succedd.
2618          */
2619         preempt_disable();
2620         c = __this_cpu_ptr(s->cpu_slab);
2621 
2622         tid = c->tid;
2623         preempt_enable();
2624 
2625         if (likely(page == c->page)) {
2626                 set_freepointer(s, object, c->freelist);
2627 
2628                 if (unlikely(!this_cpu_cmpxchg_double(
2629                                 s->cpu_slab->freelist, s->cpu_slab->tid,
2630                                 c->freelist, tid,
2631                                 object, next_tid(tid)))) {
2632 
2633                         note_cmpxchg_failure("slab_free", s, tid);
2634                         goto redo;
2635                 }
2636                 stat(s, FREE_FASTPATH);
2637         } else
2638                 __slab_free(s, page, x, addr);
2639 
2640 }
2641 
2642 void kmem_cache_free(struct kmem_cache *s, void *x)
2643 {
2644         s = cache_from_obj(s, x);
2645         if (!s)
2646                 return;
2647         slab_free(s, virt_to_head_page(x), x, _RET_IP_);
2648         trace_kmem_cache_free(_RET_IP_, x);
2649 }
2650 EXPORT_SYMBOL(kmem_cache_free);
2651 
2652 /*
2653  * Object placement in a slab is made very easy because we always start at
2654  * offset 0. If we tune the size of the object to the alignment then we can
2655  * get the required alignment by putting one properly sized object after
2656  * another.
2657  *
2658  * Notice that the allocation order determines the sizes of the per cpu
2659  * caches. Each processor has always one slab available for allocations.
2660  * Increasing the allocation order reduces the number of times that slabs
2661  * must be moved on and off the partial lists and is therefore a factor in
2662  * locking overhead.
2663  */
2664 
2665 /*
2666  * Mininum / Maximum order of slab pages. This influences locking overhead
2667  * and slab fragmentation. A higher order reduces the number of partial slabs
2668  * and increases the number of allocations possible without having to
2669  * take the list_lock.
2670  */
2671 static int slub_min_order;
2672 static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
2673 static int slub_min_objects;
2674 
2675 /*
2676  * Merge control. If this is set then no merging of slab caches will occur.
2677  * (Could be removed. This was introduced to pacify the merge skeptics.)
2678  */
2679 static int slub_nomerge;
2680 
2681 /*
2682  * Calculate the order of allocation given an slab object size.
2683  *
2684  * The order of allocation has significant impact on performance and other
2685  * system components. Generally order 0 allocations should be preferred since
2686  * order 0 does not cause fragmentation in the page allocator. Larger objects
2687  * be problematic to put into order 0 slabs because there may be too much
2688  * unused space left. We go to a higher order if more than 1/16th of the slab
2689  * would be wasted.
2690  *
2691  * In order to reach satisfactory performance we must ensure that a minimum
2692  * number of objects is in one slab. Otherwise we may generate too much
2693  * activity on the partial lists which requires taking the list_lock. This is
2694  * less a concern for large slabs though which are rarely used.
2695  *
2696  * slub_max_order specifies the order where we begin to stop considering the
2697  * number of objects in a slab as critical. If we reach slub_max_order then
2698  * we try to keep the page order as low as possible. So we accept more waste
2699  * of space in favor of a small page order.
2700  *
2701  * Higher order allocations also allow the placement of more objects in a
2702  * slab and thereby reduce object handling overhead. If the user has
2703  * requested a higher mininum order then we start with that one instead of
2704  * the smallest order which will fit the object.
2705  */
2706 static inline int slab_order(int size, int min_objects,
2707                                 int max_order, int fract_leftover, int reserved)
2708 {
2709         int order;
2710         int rem;
2711         int min_order = slub_min_order;
2712 
2713         if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
2714                 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
2715 
2716         for (order = max(min_order,
2717                                 fls(min_objects * size - 1) - PAGE_SHIFT);
2718                         order <= max_order; order++) {
2719 
2720                 unsigned long slab_size = PAGE_SIZE << order;
2721 
2722                 if (slab_size < min_objects * size + reserved)
2723                         continue;
2724 
2725                 rem = (slab_size - reserved) % size;
2726 
2727                 if (rem <= slab_size / fract_leftover)
2728                         break;
2729 
2730         }
2731 
2732         return order;
2733 }
2734 
2735 static inline int calculate_order(int size, int reserved)
2736 {
2737         int order;
2738         int min_objects;
2739         int fraction;
2740         int max_objects;
2741 
2742         /*
2743          * Attempt to find best configuration for a slab. This
2744          * works by first attempting to generate a layout with
2745          * the best configuration and backing off gradually.
2746          *
2747          * First we reduce the acceptable waste in a slab. Then
2748          * we reduce the minimum objects required in a slab.
2749          */
2750         min_objects = slub_min_objects;
2751         if (!min_objects)
2752                 min_objects = 4 * (fls(nr_cpu_ids) + 1);
2753         max_objects = order_objects(slub_max_order, size, reserved);
2754         min_objects = min(min_objects, max_objects);
2755 
2756         while (min_objects > 1) {
2757                 fraction = 16;
2758                 while (fraction >= 4) {
2759                         order = slab_order(size, min_objects,
2760                                         slub_max_order, fraction, reserved);
2761                         if (order <= slub_max_order)
2762                                 return order;
2763                         fraction /= 2;
2764                 }
2765                 min_objects--;
2766         }
2767 
2768         /*
2769          * We were unable to place multiple objects in a slab. Now
2770          * lets see if we can place a single object there.
2771          */
2772         order = slab_order(size, 1, slub_max_order, 1, reserved);
2773         if (order <= slub_max_order)
2774                 return order;
2775 
2776         /*
2777          * Doh this slab cannot be placed using slub_max_order.
2778          */
2779         order = slab_order(size, 1, MAX_ORDER, 1, reserved);
2780         if (order < MAX_ORDER)
2781                 return order;
2782         return -ENOSYS;
2783 }
2784 
2785 static void
2786 init_kmem_cache_node(struct kmem_cache_node *n)
2787 {
2788         n->nr_partial = 0;
2789         spin_lock_init(&n->list_lock);
2790         INIT_LIST_HEAD(&n->partial);
2791 #ifdef CONFIG_SLUB_DEBUG
2792         atomic_long_set(&n->nr_slabs, 0);
2793         atomic_long_set(&n->total_objects, 0);
2794         INIT_LIST_HEAD(&n->full);
2795 #endif
2796 }
2797 
2798 static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
2799 {
2800         BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
2801                         KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
2802 
2803         /*
2804          * Must align to double word boundary for the double cmpxchg
2805          * instructions to work; see __pcpu_double_call_return_bool().
2806          */
2807         s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2808                                      2 * sizeof(void *));
2809 
2810         if (!s->cpu_slab)
2811                 return 0;
2812 
2813         init_kmem_cache_cpus(s);
2814 
2815         return 1;
2816 }
2817 
2818 static struct kmem_cache *kmem_cache_node;
2819 
2820 /*
2821  * No kmalloc_node yet so do it by hand. We know that this is the first
2822  * slab on the node for this slabcache. There are no concurrent accesses
2823  * possible.
2824  *
2825  * Note that this function only works on the kmalloc_node_cache
2826  * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2827  * memory on a fresh node that has no slab structures yet.
2828  */
2829 static void early_kmem_cache_node_alloc(int node)
2830 {
2831         struct page *page;
2832         struct kmem_cache_node *n;
2833 
2834         BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
2835 
2836         page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
2837 
2838         BUG_ON(!page);
2839         if (page_to_nid(page) != node) {
2840                 printk(KERN_ERR "SLUB: Unable to allocate memory from "
2841                                 "node %d\n", node);
2842                 printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2843                                 "in order to be able to continue\n");
2844         }
2845 
2846         n = page->freelist;
2847         BUG_ON(!n);
2848         page->freelist = get_freepointer(kmem_cache_node, n);
2849         page->inuse = 1;
2850         page->frozen = 0;
2851         kmem_cache_node->node[node] = n;
2852 #ifdef CONFIG_SLUB_DEBUG
2853         init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
2854         init_tracking(kmem_cache_node, n);
2855 #endif
2856         init_kmem_cache_node(n);
2857         inc_slabs_node(kmem_cache_node, node, page->objects);
2858 
2859         add_partial(n, page, DEACTIVATE_TO_HEAD);
2860 }
2861 
2862 static void free_kmem_cache_nodes(struct kmem_cache *s)
2863 {
2864         int node;
2865 
2866         for_each_node_state(node, N_NORMAL_MEMORY) {
2867                 struct kmem_cache_node *n = s->node[node];
2868 
2869                 if (n)
2870                         kmem_cache_free(kmem_cache_node, n);
2871 
2872                 s->node[node] = NULL;
2873         }
2874 }
2875 
2876 static int init_kmem_cache_nodes(struct kmem_cache *s)
2877 {
2878         int node;
2879 
2880         for_each_node_state(node, N_NORMAL_MEMORY) {
2881                 struct kmem_cache_node *n;
2882 
2883                 if (slab_state == DOWN) {
2884                         early_kmem_cache_node_alloc(node);
2885                         continue;
2886                 }
2887                 n = kmem_cache_alloc_node(kmem_cache_node,
2888                                                 GFP_KERNEL, node);
2889 
2890                 if (!n) {
2891                         free_kmem_cache_nodes(s);
2892                         return 0;
2893                 }
2894 
2895                 s->node[node] = n;
2896                 init_kmem_cache_node(n);
2897         }
2898         return 1;
2899 }
2900 
2901 static void set_min_partial(struct kmem_cache *s, unsigned long min)
2902 {
2903         if (min < MIN_PARTIAL)
2904                 min = MIN_PARTIAL;
2905         else if (min > MAX_PARTIAL)
2906                 min = MAX_PARTIAL;
2907         s->min_partial = min;
2908 }
2909 
2910 /*
2911  * calculate_sizes() determines the order and the distribution of data within
2912  * a slab object.
2913  */
2914 static int calculate_sizes(struct kmem_cache *s, int forced_order)
2915 {
2916         unsigned long flags = s->flags;
2917         unsigned long size = s->object_size;
2918         int order;
2919 
2920         /*
2921          * Round up object size to the next word boundary. We can only
2922          * place the free pointer at word boundaries and this determines
2923          * the possible location of the free pointer.
2924          */
2925         size = ALIGN(size, sizeof(void *));
2926 
2927 #ifdef CONFIG_SLUB_DEBUG
2928         /*
2929          * Determine if we can poison the object itself. If the user of
2930          * the slab may touch the object after free or before allocation
2931          * then we should never poison the object itself.
2932          */
2933         if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2934                         !s->ctor)
2935                 s->flags |= __OBJECT_POISON;
2936         else
2937                 s->flags &= ~__OBJECT_POISON;
2938 
2939 
2940         /*
2941          * If we are Redzoning then check if there is some space between the
2942          * end of the object and the free pointer. If not then add an
2943          * additional word to have some bytes to store Redzone information.
2944          */
2945         if ((flags & SLAB_RED_ZONE) && size == s->object_size)
2946                 size += sizeof(void *);
2947 #endif
2948 
2949         /*
2950          * With that we have determined the number of bytes in actual use
2951          * by the object. This is the potential offset to the free pointer.
2952          */
2953         s->inuse = size;
2954 
2955         if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2956                 s->ctor)) {
2957                 /*
2958                  * Relocate free pointer after the object if it is not
2959                  * permitted to overwrite the first word of the object on
2960                  * kmem_cache_free.
2961                  *
2962                  * This is the case if we do RCU, have a constructor or
2963                  * destructor or are poisoning the objects.
2964                  */
2965                 s->offset = size;
2966                 size += sizeof(void *);
2967         }
2968 
2969 #ifdef CONFIG_SLUB_DEBUG
2970         if (flags & SLAB_STORE_USER)
2971                 /*
2972                  * Need to store information about allocs and frees after
2973                  * the object.
2974                  */
2975                 size += 2 * sizeof(struct track);
2976 
2977         if (flags & SLAB_RED_ZONE)
2978                 /*
2979                  * Add some empty padding so that we can catch
2980                  * overwrites from earlier objects rather than let
2981                  * tracking information or the free pointer be
2982                  * corrupted if a user writes before the start
2983                  * of the object.
2984                  */
2985                 size += sizeof(void *);
2986 #endif
2987 
2988         /*
2989          * SLUB stores one object immediately after another beginning from
2990          * offset 0. In order to align the objects we have to simply size
2991          * each object to conform to the alignment.
2992          */
2993         size = ALIGN(size, s->align);
2994         s->size = size;
2995         if (forced_order >= 0)
2996                 order = forced_order;
2997         else
2998                 order = calculate_order(size, s->reserved);
2999 
3000         if (order < 0)
3001                 return 0;
3002 
3003         s->allocflags = 0;
3004         if (order)
3005                 s->allocflags |= __GFP_COMP;
3006 
3007         if (s->flags & SLAB_CACHE_DMA)
3008                 s->allocflags |= GFP_DMA;
3009 
3010         if (s->flags & SLAB_RECLAIM_ACCOUNT)
3011                 s->allocflags |= __GFP_RECLAIMABLE;
3012 
3013         /*
3014          * Determine the number of objects per slab
3015          */
3016         s->oo = oo_make(order, size, s->reserved);
3017         s->min = oo_make(get_order(size), size, s->reserved);
3018         if (oo_objects(s->oo) > oo_objects(s->max))
3019                 s->max = s->oo;
3020 
3021         return !!oo_objects(s->oo);
3022 }
3023 
3024 static int kmem_cache_open(struct kmem_cache *s, unsigned long flags)
3025 {
3026         s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3027         s->reserved = 0;
3028 
3029         if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3030                 s->reserved = sizeof(struct rcu_head);
3031 
3032         if (!calculate_sizes(s, -1))
3033                 goto error;
3034         if (disable_higher_order_debug) {
3035                 /*
3036                  * Disable debugging flags that store metadata if the min slab
3037                  * order increased.
3038                  */
3039                 if (get_order(s->size) > get_order(s->object_size)) {
3040                         s->flags &= ~DEBUG_METADATA_FLAGS;
3041                         s->offset = 0;
3042                         if (!calculate_sizes(s, -1))
3043                                 goto error;
3044                 }
3045         }
3046 
3047 #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3048     defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3049         if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
3050                 /* Enable fast mode */
3051                 s->flags |= __CMPXCHG_DOUBLE;
3052 #endif
3053 
3054         /*
3055          * The larger the object size is, the more pages we want on the partial
3056          * list to avoid pounding the page allocator excessively.
3057          */
3058         set_min_partial(s, ilog2(s->size) / 2);
3059 
3060         /*
3061          * cpu_partial determined the maximum number of objects kept in the
3062          * per cpu partial lists of a processor.
3063          *
3064          * Per cpu partial lists mainly contain slabs that just have one
3065          * object freed. If they are used for allocation then they can be
3066          * filled up again with minimal effort. The slab will never hit the
3067          * per node partial lists and therefore no locking will be required.
3068          *
3069          * This setting also determines
3070          *
3071          * A) The number of objects from per cpu partial slabs dumped to the
3072          *    per node list when we reach the limit.
3073          * B) The number of objects in cpu partial slabs to extract from the
3074          *    per node list when we run out of per cpu objects. We only fetch 50%
3075          *    to keep some capacity around for frees.
3076          */
3077         if (!kmem_cache_has_cpu_partial(s))
3078                 s->cpu_partial = 0;
3079         else if (s->size >= PAGE_SIZE)
3080                 s->cpu_partial = 2;
3081         else if (s->size >= 1024)
3082                 s->cpu_partial = 6;
3083         else if (s->size >= 256)
3084                 s->cpu_partial = 13;
3085         else
3086                 s->cpu_partial = 30;
3087 
3088 #ifdef CONFIG_NUMA
3089         s->remote_node_defrag_ratio = 1000;
3090 #endif
3091         if (!init_kmem_cache_nodes(s))
3092                 goto error;
3093 
3094         if (alloc_kmem_cache_cpus(s))
3095                 return 0;
3096 
3097         free_kmem_cache_nodes(s);
3098 error:
3099         if (flags & SLAB_PANIC)
3100                 panic("Cannot create slab %s size=%lu realsize=%u "
3101                         "order=%u offset=%u flags=%lx\n",
3102                         s->name, (unsigned long)s->size, s->size, oo_order(s->oo),
3103                         s->offset, flags);
3104         return -EINVAL;
3105 }
3106 
3107 static void list_slab_objects(struct kmem_cache *s, struct page *page,
3108                                                         const char *text)
3109 {
3110 #ifdef CONFIG_SLUB_DEBUG
3111         void *addr = page_address(page);
3112         void *p;
3113         unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3114                                      sizeof(long), GFP_ATOMIC);
3115         if (!map)
3116                 return;
3117         slab_err(s, page, text, s->name);
3118         slab_lock(page);
3119 
3120         get_map(s, page, map);
3121         for_each_object(p, s, addr, page->objects) {
3122 
3123                 if (!test_bit(slab_index(p, s, addr), map)) {
3124                         printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
3125                                                         p, p - addr);
3126                         print_tracking(s, p);
3127                 }
3128         }
3129         slab_unlock(page);
3130         kfree(map);
3131 #endif
3132 }
3133 
3134 /*
3135  * Attempt to free all partial slabs on a node.
3136  * This is called from kmem_cache_close(). We must be the last thread
3137  * using the cache and therefore we do not need to lock anymore.
3138  */
3139 static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3140 {
3141         struct page *page, *h;
3142 
3143         list_for_each_entry_safe(page, h, &n->partial, lru) {
3144                 if (!page->inuse) {
3145                         remove_partial(n, page);
3146                         discard_slab(s, page);
3147                 } else {
3148                         list_slab_objects(s, page,
3149                         "Objects remaining in %s on kmem_cache_close()");
3150                 }
3151         }
3152 }
3153 
3154 /*
3155  * Release all resources used by a slab cache.
3156  */
3157 static inline int kmem_cache_close(struct kmem_cache *s)
3158 {
3159         int node;
3160 
3161         flush_all(s);
3162         /* Attempt to free all objects */
3163         for_each_node_state(node, N_NORMAL_MEMORY) {
3164                 struct kmem_cache_node *n = get_node(s, node);
3165 
3166                 free_partial(s, n);
3167                 if (n->nr_partial || slabs_node(s, node))
3168                         return 1;
3169         }
3170         free_percpu(s->cpu_slab);
3171         free_kmem_cache_nodes(s);
3172         return 0;
3173 }
3174 
3175 int __kmem_cache_shutdown(struct kmem_cache *s)
3176 {
3177         int rc = kmem_cache_close(s);
3178 
3179         if (!rc) {
3180                 /*
3181                  * We do the same lock strategy around sysfs_slab_add, see
3182                  * __kmem_cache_create. Because this is pretty much the last
3183                  * operation we do and the lock will be released shortly after
3184                  * that in slab_common.c, we could just move sysfs_slab_remove
3185                  * to a later point in common code. We should do that when we
3186                  * have a common sysfs framework for all allocators.
3187                  */
3188                 mutex_unlock(&slab_mutex);
3189                 sysfs_slab_remove(s);
3190                 mutex_lock(&slab_mutex);
3191         }
3192 
3193         return rc;
3194 }
3195 
3196 /********************************************************************
3197  *              Kmalloc subsystem
3198  *******************************************************************/
3199 
3200 static int __init setup_slub_min_order(char *str)
3201 {
3202         get_option(&str, &slub_min_order);
3203 
3204         return 1;
3205 }
3206 
3207 __setup("slub_min_order=", setup_slub_min_order);
3208 
3209 static int __init setup_slub_max_order(char *str)
3210 {
3211         get_option(&str, &slub_max_order);
3212         slub_max_order = min(slub_max_order, MAX_ORDER - 1);
3213 
3214         return 1;
3215 }
3216 
3217 __setup("slub_max_order=", setup_slub_max_order);
3218 
3219 static int __init setup_slub_min_objects(char *str)
3220 {
3221         get_option(&str, &slub_min_objects);
3222 
3223         return 1;
3224 }
3225 
3226 __setup("slub_min_objects=", setup_slub_min_objects);
3227 
3228 static int __init setup_slub_nomerge(char *str)
3229 {
3230         slub_nomerge = 1;
3231         return 1;
3232 }
3233 
3234 __setup("slub_nomerge", setup_slub_nomerge);
3235 
3236 void *__kmalloc(size_t size, gfp_t flags)
3237 {
3238         struct kmem_cache *s;
3239         void *ret;
3240 
3241         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3242                 return kmalloc_large(size, flags);
3243 
3244         s = kmalloc_slab(size, flags);
3245 
3246         if (unlikely(ZERO_OR_NULL_PTR(s)))
3247                 return s;
3248 
3249         ret = slab_alloc(s, flags, _RET_IP_);
3250 
3251         trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3252 
3253         return ret;
3254 }
3255 EXPORT_SYMBOL(__kmalloc);
3256 
3257 #ifdef CONFIG_NUMA
3258 static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3259 {
3260         struct page *page;
3261         void *ptr = NULL;
3262 
3263         flags |= __GFP_COMP | __GFP_NOTRACK | __GFP_KMEMCG;
3264         page = alloc_pages_node(node, flags, get_order(size));
3265         if (page)
3266                 ptr = page_address(page);
3267 
3268         kmemleak_alloc(ptr, size, 1, flags);
3269         return ptr;
3270 }
3271 
3272 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3273 {
3274         struct kmem_cache *s;
3275         void *ret;
3276 
3277         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3278                 ret = kmalloc_large_node(size, flags, node);
3279 
3280                 trace_kmalloc_node(_RET_IP_, ret,
3281                                    size, PAGE_SIZE << get_order(size),
3282                                    flags, node);
3283 
3284                 return ret;
3285         }
3286 
3287         s = kmalloc_slab(size, flags);
3288 
3289         if (unlikely(ZERO_OR_NULL_PTR(s)))
3290                 return s;
3291 
3292         ret = slab_alloc_node(s, flags, node, _RET_IP_);
3293 
3294         trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3295 
3296         return ret;
3297 }
3298 EXPORT_SYMBOL(__kmalloc_node);
3299 #endif
3300 
3301 size_t ksize(const void *object)
3302 {
3303         struct page *page;
3304 
3305         if (unlikely(object == ZERO_SIZE_PTR))
3306                 return 0;
3307 
3308         page = virt_to_head_page(object);
3309 
3310         if (unlikely(!PageSlab(page))) {
3311                 WARN_ON(!PageCompound(page));
3312                 return PAGE_SIZE << compound_order(page);
3313         }
3314 
3315         return slab_ksize(page->slab_cache);
3316 }
3317 EXPORT_SYMBOL(ksize);
3318 
3319 #ifdef CONFIG_SLUB_DEBUG
3320 bool verify_mem_not_deleted(const void *x)
3321 {
3322         struct page *page;
3323         void *object = (void *)x;
3324         unsigned long flags;
3325         bool rv;
3326 
3327         if (unlikely(ZERO_OR_NULL_PTR(x)))
3328                 return false;
3329 
3330         local_irq_save(flags);
3331 
3332         page = virt_to_head_page(x);
3333         if (unlikely(!PageSlab(page))) {
3334                 /* maybe it was from stack? */
3335                 rv = true;
3336                 goto out_unlock;
3337         }
3338 
3339         slab_lock(page);
3340         if (on_freelist(page->slab_cache, page, object)) {
3341                 object_err(page->slab_cache, page, object, "Object is on free-list");
3342                 rv = false;
3343         } else {
3344                 rv = true;
3345         }
3346         slab_unlock(page);
3347 
3348 out_unlock:
3349         local_irq_restore(flags);
3350         return rv;
3351 }
3352 EXPORT_SYMBOL(verify_mem_not_deleted);
3353 #endif
3354 
3355 void kfree(const void *x)
3356 {
3357         struct page *page;
3358         void *object = (void *)x;
3359 
3360         trace_kfree(_RET_IP_, x);
3361 
3362         if (unlikely(ZERO_OR_NULL_PTR(x)))
3363                 return;
3364 
3365         page = virt_to_head_page(x);
3366         if (unlikely(!PageSlab(page))) {
3367                 BUG_ON(!PageCompound(page));
3368                 kmemleak_free(x);
3369                 __free_memcg_kmem_pages(page, compound_order(page));
3370                 return;
3371         }
3372         slab_free(page->slab_cache, page, object, _RET_IP_);
3373 }
3374 EXPORT_SYMBOL(kfree);
3375 
3376 /*
3377  * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3378  * the remaining slabs by the number of items in use. The slabs with the
3379  * most items in use come first. New allocations will then fill those up
3380  * and thus they can be removed from the partial lists.
3381  *
3382  * The slabs with the least items are placed last. This results in them
3383  * being allocated from last increasing the chance that the last objects
3384  * are freed in them.
3385  */
3386 int kmem_cache_shrink(struct kmem_cache *s)
3387 {
3388         int node;
3389         int i;
3390         struct kmem_cache_node *n;
3391         struct page *page;
3392         struct page *t;
3393         int objects = oo_objects(s->max);
3394         struct list_head *slabs_by_inuse =
3395                 kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
3396         unsigned long flags;
3397 
3398         if (!slabs_by_inuse)
3399                 return -ENOMEM;
3400 
3401         flush_all(s);
3402         for_each_node_state(node, N_NORMAL_MEMORY) {
3403                 n = get_node(s, node);
3404 
3405                 if (!n->nr_partial)
3406                         continue;
3407 
3408                 for (i = 0; i < objects; i++)
3409                         INIT_LIST_HEAD(slabs_by_inuse + i);
3410 
3411                 spin_lock_irqsave(&n->list_lock, flags);
3412 
3413                 /*
3414                  * Build lists indexed by the items in use in each slab.
3415                  *
3416                  * Note that concurrent frees may occur while we hold the
3417                  * list_lock. page->inuse here is the upper limit.
3418                  */
3419                 list_for_each_entry_safe(page, t, &n->partial, lru) {
3420                         list_move(&page->lru, slabs_by_inuse + page->inuse);
3421                         if (!page->inuse)
3422                                 n->nr_partial--;
3423                 }
3424 
3425                 /*
3426                  * Rebuild the partial list with the slabs filled up most
3427                  * first and the least used slabs at the end.
3428                  */
3429                 for (i = objects - 1; i > 0; i--)
3430                         list_splice(slabs_by_inuse + i, n->partial.prev);
3431 
3432                 spin_unlock_irqrestore(&n->list_lock, flags);
3433 
3434                 /* Release empty slabs */
3435                 list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
3436                         discard_slab(s, page);
3437         }
3438 
3439         kfree(slabs_by_inuse);
3440         return 0;
3441 }
3442 EXPORT_SYMBOL(kmem_cache_shrink);
3443 
3444 static int slab_mem_going_offline_callback(void *arg)
3445 {
3446         struct kmem_cache *s;
3447 
3448         mutex_lock(&slab_mutex);
3449         list_for_each_entry(s, &slab_caches, list)
3450                 kmem_cache_shrink(s);
3451         mutex_unlock(&slab_mutex);
3452 
3453         return 0;
3454 }
3455 
3456 static void slab_mem_offline_callback(void *arg)
3457 {
3458         struct kmem_cache_node *n;
3459         struct kmem_cache *s;
3460         struct memory_notify *marg = arg;
3461         int offline_node;
3462 
3463         offline_node = marg->status_change_nid_normal;
3464 
3465         /*
3466          * If the node still has available memory. we need kmem_cache_node
3467          * for it yet.
3468          */
3469         if (offline_node < 0)
3470                 return;
3471 
3472         mutex_lock(&slab_mutex);
3473         list_for_each_entry(s, &slab_caches, list) {
3474                 n = get_node(s, offline_node);
3475                 if (n) {
3476                         /*
3477                          * if n->nr_slabs > 0, slabs still exist on the node
3478                          * that is going down. We were unable to free them,
3479                          * and offline_pages() function shouldn't call this
3480                          * callback. So, we must fail.
3481                          */
3482                         BUG_ON(slabs_node(s, offline_node));
3483 
3484                         s->node[offline_node] = NULL;
3485                         kmem_cache_free(kmem_cache_node, n);
3486                 }
3487         }
3488         mutex_unlock(&slab_mutex);
3489 }
3490 
3491 static int slab_mem_going_online_callback(void *arg)
3492 {
3493         struct kmem_cache_node *n;
3494         struct kmem_cache *s;
3495         struct memory_notify *marg = arg;
3496         int nid = marg->status_change_nid_normal;
3497         int ret = 0;
3498 
3499         /*
3500          * If the node's memory is already available, then kmem_cache_node is
3501          * already created. Nothing to do.
3502          */
3503         if (nid < 0)
3504                 return 0;
3505 
3506         /*
3507          * We are bringing a node online. No memory is available yet. We must
3508          * allocate a kmem_cache_node structure in order to bring the node
3509          * online.
3510          */
3511         mutex_lock(&slab_mutex);
3512         list_for_each_entry(s, &slab_caches, list) {
3513                 /*
3514                  * XXX: kmem_cache_alloc_node will fallback to other nodes
3515                  *      since memory is not yet available from the node that
3516                  *      is brought up.
3517                  */
3518                 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3519                 if (!n) {
3520                         ret = -ENOMEM;
3521                         goto out;
3522                 }
3523                 init_kmem_cache_node(n);
3524                 s->node[nid] = n;
3525         }
3526 out:
3527         mutex_unlock(&slab_mutex);
3528         return ret;
3529 }
3530 
3531 static int slab_memory_callback(struct notifier_block *self,
3532                                 unsigned long action, void *arg)
3533 {
3534         int ret = 0;
3535 
3536         switch (action) {
3537         case MEM_GOING_ONLINE:
3538                 ret = slab_mem_going_online_callback(arg);
3539                 break;
3540         case MEM_GOING_OFFLINE:
3541                 ret = slab_mem_going_offline_callback(arg);
3542                 break;
3543         case MEM_OFFLINE:
3544         case MEM_CANCEL_ONLINE:
3545                 slab_mem_offline_callback(arg);
3546                 break;
3547         case MEM_ONLINE:
3548         case MEM_CANCEL_OFFLINE:
3549                 break;
3550         }
3551         if (ret)
3552                 ret = notifier_from_errno(ret);
3553         else
3554                 ret = NOTIFY_OK;
3555         return ret;
3556 }
3557 
3558 static struct notifier_block slab_memory_callback_nb = {
3559         .notifier_call = slab_memory_callback,
3560         .priority = SLAB_CALLBACK_PRI,
3561 };
3562 
3563 /********************************************************************
3564  *                      Basic setup of slabs
3565  *******************************************************************/
3566 
3567 /*
3568  * Used for early kmem_cache structures that were allocated using
3569  * the page allocator. Allocate them properly then fix up the pointers
3570  * that may be pointing to the wrong kmem_cache structure.
3571  */
3572 
3573 static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
3574 {
3575         int node;
3576         struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
3577 
3578         memcpy(s, static_cache, kmem_cache->object_size);
3579 
3580         /*
3581          * This runs very early, and only the boot processor is supposed to be
3582          * up.  Even if it weren't true, IRQs are not up so we couldn't fire
3583          * IPIs around.
3584          */
3585         __flush_cpu_slab(s, smp_processor_id());
3586         for_each_node_state(node, N_NORMAL_MEMORY) {
3587                 struct kmem_cache_node *n = get_node(s, node);
3588                 struct page *p;
3589 
3590                 if (n) {
3591                         list_for_each_entry(p, &n->partial, lru)
3592                                 p->slab_cache = s;
3593 
3594 #ifdef CONFIG_SLUB_DEBUG
3595                         list_for_each_entry(p, &n->full, lru)
3596                                 p->slab_cache = s;
3597 #endif
3598                 }
3599         }
3600         list_add(&s->list, &slab_caches);
3601         return s;
3602 }
3603 
3604 void __init kmem_cache_init(void)
3605 {
3606         static __initdata struct kmem_cache boot_kmem_cache,
3607                 boot_kmem_cache_node;
3608 
3609         if (debug_guardpage_minorder())
3610                 slub_max_order = 0;
3611 
3612         kmem_cache_node = &boot_kmem_cache_node;
3613         kmem_cache = &boot_kmem_cache;
3614 
3615         create_boot_cache(kmem_cache_node, "kmem_cache_node",
3616                 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN);
3617 
3618         register_hotmemory_notifier(&slab_memory_callback_nb);
3619 
3620         /* Able to allocate the per node structures */
3621         slab_state = PARTIAL;
3622 
3623         create_boot_cache(kmem_cache, "kmem_cache",
3624                         offsetof(struct kmem_cache, node) +
3625                                 nr_node_ids * sizeof(struct kmem_cache_node *),
3626                        SLAB_HWCACHE_ALIGN);
3627 
3628         kmem_cache = bootstrap(&boot_kmem_cache);
3629 
3630         /*
3631          * Allocate kmem_cache_node properly from the kmem_cache slab.
3632          * kmem_cache_node is separately allocated so no need to
3633          * update any list pointers.
3634          */
3635         kmem_cache_node = bootstrap(&boot_kmem_cache_node);
3636 
3637         /* Now we can use the kmem_cache to allocate kmalloc slabs */
3638         create_kmalloc_caches(0);
3639 
3640 #ifdef CONFIG_SMP
3641         register_cpu_notifier(&slab_notifier);
3642 #endif
3643 
3644         printk(KERN_INFO
3645                 "SLUB: HWalign=%d, Order=%d-%d, MinObjects=%d,"
3646                 " CPUs=%d, Nodes=%d\n",
3647                 cache_line_size(),
3648                 slub_min_order, slub_max_order, slub_min_objects,
3649                 nr_cpu_ids, nr_node_ids);
3650 }
3651 
3652 void __init kmem_cache_init_late(void)
3653 {
3654 }
3655 
3656 /*
3657  * Find a mergeable slab cache
3658  */
3659 static int slab_unmergeable(struct kmem_cache *s)
3660 {
3661         if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3662                 return 1;
3663 
3664         if (s->ctor)
3665                 return 1;
3666 
3667         /*
3668          * We may have set a slab to be unmergeable during bootstrap.
3669          */
3670         if (s->refcount < 0)
3671                 return 1;
3672 
3673         return 0;
3674 }
3675 
3676 static struct kmem_cache *find_mergeable(struct mem_cgroup *memcg, size_t size,
3677                 size_t align, unsigned long flags, const char *name,
3678                 void (*ctor)(void *))
3679 {
3680         struct kmem_cache *s;
3681 
3682         if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3683                 return NULL;
3684 
3685         if (ctor)
3686                 return NULL;
3687 
3688         size = ALIGN(size, sizeof(void *));
3689         align = calculate_alignment(flags, align, size);
3690         size = ALIGN(size, align);
3691         flags = kmem_cache_flags(size, flags, name, NULL);
3692 
3693         list_for_each_entry(s, &slab_caches, list) {
3694                 if (slab_unmergeable(s))
3695                         continue;
3696 
3697                 if (size > s->size)
3698                         continue;
3699 
3700                 if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3701                                 continue;
3702                 /*
3703                  * Check if alignment is compatible.
3704                  * Courtesy of Adrian Drzewiecki
3705                  */
3706                 if ((s->size & ~(align - 1)) != s->size)
3707                         continue;
3708 
3709                 if (s->size - size >= sizeof(void *))
3710                         continue;
3711 
3712                 if (!cache_match_memcg(s, memcg))
3713                         continue;
3714 
3715                 return s;
3716         }
3717         return NULL;
3718 }
3719 
3720 struct kmem_cache *
3721 __kmem_cache_alias(struct mem_cgroup *memcg, const char *name, size_t size,
3722                    size_t align, unsigned long flags, void (*ctor)(void *))
3723 {
3724         struct kmem_cache *s;
3725 
3726         s = find_mergeable(memcg, size, align, flags, name, ctor);
3727         if (s) {
3728                 s->refcount++;
3729                 /*
3730                  * Adjust the object sizes so that we clear
3731                  * the complete object on kzalloc.
3732                  */
3733                 s->object_size = max(s->object_size, (int)size);
3734                 s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3735 
3736                 if (sysfs_slab_alias(s, name)) {
3737                         s->refcount--;
3738                         s = NULL;
3739                 }
3740         }
3741 
3742         return s;
3743 }
3744 
3745 int __kmem_cache_create(struct kmem_cache *s, unsigned long flags)
3746 {
3747         int err;
3748 
3749         err = kmem_cache_open(s, flags);
3750         if (err)
3751                 return err;
3752 
3753         /* Mutex is not taken during early boot */
3754         if (slab_state <= UP)
3755                 return 0;
3756 
3757         memcg_propagate_slab_attrs(s);
3758         mutex_unlock(&slab_mutex);
3759         err = sysfs_slab_add(s);
3760         mutex_lock(&slab_mutex);
3761 
3762         if (err)
3763                 kmem_cache_close(s);
3764 
3765         return err;
3766 }
3767 
3768 #ifdef CONFIG_SMP
3769 /*
3770  * Use the cpu notifier to insure that the cpu slabs are flushed when
3771  * necessary.
3772  */
3773 static int slab_cpuup_callback(struct notifier_block *nfb,
3774                 unsigned long action, void *hcpu)
3775 {
3776         long cpu = (long)hcpu;
3777         struct kmem_cache *s;
3778         unsigned long flags;
3779 
3780         switch (action) {
3781         case CPU_UP_CANCELED:
3782         case CPU_UP_CANCELED_FROZEN:
3783         case CPU_DEAD:
3784         case CPU_DEAD_FROZEN:
3785                 mutex_lock(&slab_mutex);
3786                 list_for_each_entry(s, &slab_caches, list) {
3787                         local_irq_save(flags);
3788                         __flush_cpu_slab(s, cpu);
3789                         local_irq_restore(flags);
3790                 }
3791                 mutex_unlock(&slab_mutex);
3792                 break;
3793         default:
3794                 break;
3795         }
3796         return NOTIFY_OK;
3797 }
3798 
3799 static struct notifier_block slab_notifier = {
3800         .notifier_call = slab_cpuup_callback
3801 };
3802 
3803 #endif
3804 
3805 void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
3806 {
3807         struct kmem_cache *s;
3808         void *ret;
3809 
3810         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3811                 return kmalloc_large(size, gfpflags);
3812 
3813         s = kmalloc_slab(size, gfpflags);
3814 
3815         if (unlikely(ZERO_OR_NULL_PTR(s)))
3816                 return s;
3817 
3818         ret = slab_alloc(s, gfpflags, caller);
3819 
3820         /* Honor the call site pointer we received. */
3821         trace_kmalloc(caller, ret, size, s->size, gfpflags);
3822 
3823         return ret;
3824 }
3825 
3826 #ifdef CONFIG_NUMA
3827 void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
3828                                         int node, unsigned long caller)
3829 {
3830         struct kmem_cache *s;
3831         void *ret;
3832 
3833         if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3834                 ret = kmalloc_large_node(size, gfpflags, node);
3835 
3836                 trace_kmalloc_node(caller, ret,
3837                                    size, PAGE_SIZE << get_order(size),
3838                                    gfpflags, node);
3839 
3840                 return ret;
3841         }
3842 
3843         s = kmalloc_slab(size, gfpflags);
3844 
3845         if (unlikely(ZERO_OR_NULL_PTR(s)))
3846                 return s;
3847 
3848         ret = slab_alloc_node(s, gfpflags, node, caller);
3849 
3850         /* Honor the call site pointer we received. */
3851         trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
3852 
3853         return ret;
3854 }
3855 #endif
3856 
3857 #ifdef CONFIG_SYSFS
3858 static int count_inuse(struct page *page)
3859 {
3860         return page->inuse;
3861 }
3862 
3863 static int count_total(struct page *page)
3864 {
3865         return page->objects;
3866 }
3867 #endif
3868 
3869 #ifdef CONFIG_SLUB_DEBUG
3870 static int validate_slab(struct kmem_cache *s, struct page *page,
3871                                                 unsigned long *map)
3872 {
3873         void *p;
3874         void *addr = page_address(page);
3875 
3876         if (!check_slab(s, page) ||
3877                         !on_freelist(s, page, NULL))
3878                 return 0;
3879 
3880         /* Now we know that a valid freelist exists */
3881         bitmap_zero(map, page->objects);
3882 
3883         get_map(s, page, map);
3884         for_each_object(p, s, addr, page->objects) {
3885                 if (test_bit(slab_index(p, s, addr), map))
3886                         if (!check_object(s, page, p, SLUB_RED_INACTIVE))
3887                                 return 0;
3888         }
3889 
3890         for_each_object(p, s, addr, page->objects)
3891                 if (!test_bit(slab_index(p, s, addr), map))
3892                         if (!check_object(s, page, p, SLUB_RED_ACTIVE))
3893                                 return 0;
3894         return 1;
3895 }
3896 
3897 static void validate_slab_slab(struct kmem_cache *s, struct page *page,
3898                                                 unsigned long *map)
3899 {
3900         slab_lock(page);
3901         validate_slab(s, page, map);
3902         slab_unlock(page);
3903 }
3904 
3905 static int validate_slab_node(struct kmem_cache *s,
3906                 struct kmem_cache_node *n, unsigned long *map)
3907 {
3908         unsigned long count = 0;
3909         struct page *page;
3910         unsigned long flags;
3911 
3912         spin_lock_irqsave(&n->list_lock, flags);
3913 
3914         list_for_each_entry(page, &n->partial, lru) {
3915                 validate_slab_slab(s, page, map);
3916                 count++;
3917         }
3918         if (count != n->nr_partial)
3919                 printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
3920                         "counter=%ld\n", s->name, count, n->nr_partial);
3921 
3922         if (!(s->flags & SLAB_STORE_USER))
3923                 goto out;
3924 
3925         list_for_each_entry(page, &n->full, lru) {
3926                 validate_slab_slab(s, page, map);
3927                 count++;
3928         }
3929         if (count != atomic_long_read(&n->nr_slabs))
3930                 printk(KERN_ERR "SLUB: %s %ld slabs counted but "
3931                         "counter=%ld\n", s->name, count,
3932                         atomic_long_read(&n->nr_slabs));
3933 
3934 out:
3935         spin_unlock_irqrestore(&n->list_lock, flags);
3936         return count;
3937 }
3938 
3939 static long validate_slab_cache(struct kmem_cache *s)
3940 {
3941         int node;
3942         unsigned long count = 0;
3943         unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
3944                                 sizeof(unsigned long), GFP_KERNEL);
3945 
3946         if (!map)
3947                 return -ENOMEM;
3948 
3949         flush_all(s);
3950         for_each_node_state(node, N_NORMAL_MEMORY) {
3951                 struct kmem_cache_node *n = get_node(s, node);
3952 
3953                 count += validate_slab_node(s, n, map);
3954         }
3955         kfree(map);
3956         return count;
3957 }
3958 /*
3959  * Generate lists of code addresses where slabcache objects are allocated
3960  * and freed.
3961  */
3962 
3963 struct location {
3964         unsigned long count;
3965         unsigned long addr;
3966         long long sum_time;
3967         long min_time;
3968         long max_time;
3969         long min_pid;
3970         long max_pid;
3971         DECLARE_BITMAP(cpus, NR_CPUS);
3972         nodemask_t nodes;
3973 };
3974 
3975 struct loc_track {
3976         unsigned long max;
3977         unsigned long count;
3978         struct location *loc;
3979 };
3980 
3981 static void free_loc_track(struct loc_track *t)
3982 {
3983         if (t->max)
3984                 free_pages((unsigned long)t->loc,
3985                         get_order(sizeof(struct location) * t->max));
3986 }
3987 
3988 static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
3989 {
3990         struct location *l;
3991         int order;
3992 
3993         order = get_order(sizeof(struct location) * max);
3994 
3995         l = (void *)__get_free_pages(flags, order);
3996         if (!l)
3997                 return 0;
3998 
3999         if (t->count) {
4000                 memcpy(l, t->loc, sizeof(struct location) * t->count);
4001                 free_loc_track(t);
4002         }
4003         t->max = max;
4004         t->loc = l;
4005         return 1;
4006 }
4007 
4008 static int add_location(struct loc_track *t, struct kmem_cache *s,
4009                                 const struct track *track)
4010 {
4011         long start, end, pos;
4012         struct location *l;
4013         unsigned long caddr;
4014         unsigned long age = jiffies - track->when;
4015 
4016         start = -1;
4017         end = t->count;
4018 
4019         for ( ; ; ) {
4020                 pos = start + (end - start + 1) / 2;
4021 
4022                 /*
4023                  * There is nothing at "end". If we end up there
4024                  * we need to add something to before end.
4025                  */
4026                 if (pos == end)
4027                         break;
4028 
4029                 caddr = t->loc[pos].addr;
4030                 if (track->addr == caddr) {
4031 
4032                         l = &t->loc[pos];
4033                         l->count++;
4034                         if (track->when) {
4035                                 l->sum_time += age;
4036                                 if (age < l->min_time)
4037                                         l->min_time = age;
4038                                 if (age > l->max_time)
4039                                         l->max_time = age;
4040 
4041                                 if (track->pid < l->min_pid)
4042                                         l->min_pid = track->pid;
4043                                 if (track->pid > l->max_pid)
4044                                         l->max_pid = track->pid;
4045 
4046                                 cpumask_set_cpu(track->cpu,
4047                                                 to_cpumask(l->cpus));
4048                         }
4049                         node_set(page_to_nid(virt_to_page(track)), l->nodes);
4050                         return 1;
4051                 }
4052 
4053                 if (track->addr < caddr)
4054                         end = pos;
4055                 else
4056                         start = pos;
4057         }
4058 
4059         /*
4060          * Not found. Insert new tracking element.
4061          */
4062         if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4063                 return 0;
4064 
4065         l = t->loc + pos;
4066         if (pos < t->count)
4067                 memmove(l + 1, l,
4068                         (t->count - pos) * sizeof(struct location));
4069         t->count++;
4070         l->count = 1;
4071         l->addr = track->addr;
4072         l->sum_time = age;
4073         l->min_time = age;
4074         l->max_time = age;
4075         l->min_pid = track->pid;
4076         l->max_pid = track->pid;
4077         cpumask_clear(to_cpumask(l->cpus));
4078         cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4079         nodes_clear(l->nodes);
4080         node_set(page_to_nid(virt_to_page(track)), l->nodes);
4081         return 1;
4082 }
4083 
4084 static void process_slab(struct loc_track *t, struct kmem_cache *s,
4085                 struct page *page, enum track_item alloc,
4086                 unsigned long *map)
4087 {
4088         void *addr = page_address(page);
4089         void *p;
4090 
4091         bitmap_zero(map, page->objects);
4092         get_map(s, page, map);
4093 
4094         for_each_object(p, s, addr, page->objects)
4095                 if (!test_bit(slab_index(p, s, addr), map))
4096                         add_location(t, s, get_track(s, p, alloc));
4097 }
4098 
4099 static int list_locations(struct kmem_cache *s, char *buf,
4100                                         enum track_item alloc)
4101 {
4102         int len = 0;
4103         unsigned long i;
4104         struct loc_track t = { 0, 0, NULL };
4105         int node;
4106         unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4107                                      sizeof(unsigned long), GFP_KERNEL);
4108 
4109         if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4110                                      GFP_TEMPORARY)) {
4111                 kfree(map);
4112                 return sprintf(buf, "Out of memory\n");
4113         }
4114         /* Push back cpu slabs */
4115         flush_all(s);
4116 
4117         for_each_node_state(node, N_NORMAL_MEMORY) {
4118                 struct kmem_cache_node *n = get_node(s, node);
4119                 unsigned long flags;
4120                 struct page *page;
4121 
4122                 if (!atomic_long_read(&n->nr_slabs))
4123                         continue;
4124 
4125                 spin_lock_irqsave(&n->list_lock, flags);
4126                 list_for_each_entry(page, &n->partial, lru)
4127                         process_slab(&t, s, page, alloc, map);
4128                 list_for_each_entry(page, &n->full, lru)
4129                         process_slab(&t, s, page, alloc, map);
4130                 spin_unlock_irqrestore(&n->list_lock, flags);
4131         }
4132 
4133         for (i = 0; i < t.count; i++) {
4134                 struct location *l = &t.loc[i];
4135 
4136                 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4137                         break;
4138                 len += sprintf(buf + len, "%7ld ", l->count);
4139 
4140                 if (l->addr)
4141                         len += sprintf(buf + len, "%pS", (void *)l->addr);
4142                 else
4143                         len += sprintf(buf + len, "<not-available>");
4144 
4145                 if (l->sum_time != l->min_time) {
4146                         len += sprintf(buf + len, " age=%ld/%ld/%ld",
4147                                 l->min_time,
4148                                 (long)div_u64(l->sum_time, l->count),
4149                                 l->max_time);
4150                 } else
4151                         len += sprintf(buf + len, " age=%ld",
4152                                 l->min_time);
4153 
4154                 if (l->min_pid != l->max_pid)
4155                         len += sprintf(buf + len, " pid=%ld-%ld",
4156                                 l->min_pid, l->max_pid);
4157                 else
4158                         len += sprintf(buf + len, " pid=%ld",
4159                                 l->min_pid);
4160 
4161                 if (num_online_cpus() > 1 &&
4162                                 !cpumask_empty(to_cpumask(l->cpus)) &&
4163                                 len < PAGE_SIZE - 60) {
4164                         len += sprintf(buf + len, " cpus=");
4165                         len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4166                                                  to_cpumask(l->cpus));
4167                 }
4168 
4169                 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4170                                 len < PAGE_SIZE - 60) {
4171                         len += sprintf(buf + len, " nodes=");
4172                         len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4173                                         l->nodes);
4174                 }
4175 
4176                 len += sprintf(buf + len, "\n");
4177         }
4178 
4179         free_loc_track(&t);
4180         kfree(map);
4181         if (!t.count)
4182                 len += sprintf(buf, "No data\n");
4183         return len;
4184 }
4185 #endif
4186 
4187 #ifdef SLUB_RESILIENCY_TEST
4188 static void resiliency_test(void)
4189 {
4190         u8 *p;
4191 
4192         BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4193 
4194         printk(KERN_ERR "SLUB resiliency testing\n");
4195         printk(KERN_ERR "-----------------------\n");
4196         printk(KERN_ERR "A. Corruption after allocation\n");
4197 
4198         p = kzalloc(16, GFP_KERNEL);
4199         p[16] = 0x12;
4200         printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
4201                         " 0x12->0x%p\n\n", p + 16);
4202 
4203         validate_slab_cache(kmalloc_caches[4]);
4204 
4205         /* Hmmm... The next two are dangerous */
4206         p = kzalloc(32, GFP_KERNEL);
4207         p[32 + sizeof(void *)] = 0x34;
4208         printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
4209                         " 0x34 -> -0x%p\n", p);
4210         printk(KERN_ERR
4211                 "If allocated object is overwritten then not detectable\n\n");
4212 
4213         validate_slab_cache(kmalloc_caches[5]);
4214         p = kzalloc(64, GFP_KERNEL);
4215         p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4216         *p = 0x56;
4217         printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4218                                                                         p);
4219         printk(KERN_ERR
4220                 "If allocated object is overwritten then not detectable\n\n");
4221         validate_slab_cache(kmalloc_caches[6]);
4222 
4223         printk(KERN_ERR "\nB. Corruption after free\n");
4224         p = kzalloc(128, GFP_KERNEL);
4225         kfree(p);
4226         *p = 0x78;
4227         printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4228         validate_slab_cache(kmalloc_caches[7]);
4229 
4230         p = kzalloc(256, GFP_KERNEL);
4231         kfree(p);
4232         p[50] = 0x9a;
4233         printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4234                         p);
4235         validate_slab_cache(kmalloc_caches[8]);
4236 
4237         p = kzalloc(512, GFP_KERNEL);
4238         kfree(p);
4239         p[512] = 0xab;
4240         printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4241         validate_slab_cache(kmalloc_caches[9]);
4242 }
4243 #else
4244 #ifdef CONFIG_SYSFS
4245 static void resiliency_test(void) {};
4246 #endif
4247 #endif
4248 
4249 #ifdef CONFIG_SYSFS
4250 enum slab_stat_type {
4251         SL_ALL,                 /* All slabs */
4252         SL_PARTIAL,             /* Only partially allocated slabs */
4253         SL_CPU,                 /* Only slabs used for cpu caches */
4254         SL_OBJECTS,             /* Determine allocated objects not slabs */
4255         SL_TOTAL                /* Determine object capacity not slabs */
4256 };
4257 
4258 #define SO_ALL          (1 << SL_ALL)
4259 #define SO_PARTIAL      (1 << SL_PARTIAL)
4260 #define SO_CPU          (1 << SL_CPU)
4261 #define SO_OBJECTS      (1 << SL_OBJECTS)
4262 #define SO_TOTAL        (1 << SL_TOTAL)
4263 
4264 static ssize_t show_slab_objects(struct kmem_cache *s,
4265                             char *buf, unsigned long flags)
4266 {
4267         unsigned long total = 0;
4268         int node;
4269         int x;
4270         unsigned long *nodes;
4271         unsigned long *per_cpu;
4272 
4273         nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4274         if (!nodes)
4275                 return -ENOMEM;
4276         per_cpu = nodes + nr_node_ids;
4277 
4278         if (flags & SO_CPU) {
4279                 int cpu;
4280 
4281                 for_each_possible_cpu(cpu) {
4282                         struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
4283                         int node;
4284                         struct page *page;
4285 
4286                         page = ACCESS_ONCE(c->page);
4287                         if (!page)
4288                                 continue;
4289 
4290                         node = page_to_nid(page);
4291                         if (flags & SO_TOTAL)
4292                                 x = page->objects;
4293                         else if (flags & SO_OBJECTS)
4294                                 x = page->inuse;
4295                         else
4296                                 x = 1;
4297 
4298                         total += x;
4299                         nodes[node] += x;
4300 
4301                         page = ACCESS_ONCE(c->partial);
4302                         if (page) {
4303                                 x = page->pobjects;
4304                                 total += x;
4305                                 nodes[node] += x;
4306                         }
4307 
4308                         per_cpu[node]++;
4309                 }
4310         }
4311 
4312         lock_memory_hotplug();
4313 #ifdef CONFIG_SLUB_DEBUG
4314         if (flags & SO_ALL) {
4315                 for_each_node_state(node, N_NORMAL_MEMORY) {
4316                         struct kmem_cache_node *n = get_node(s, node);
4317 
4318                 if (flags & SO_TOTAL)
4319                         x = atomic_long_read(&n->total_objects);
4320                 else if (flags & SO_OBJECTS)
4321                         x = atomic_long_read(&n->total_objects) -
4322                                 count_partial(n, count_free);
4323 
4324                         else
4325                                 x = atomic_long_read(&n->nr_slabs);
4326                         total += x;
4327                         nodes[node] += x;
4328                 }
4329 
4330         } else
4331 #endif
4332         if (flags & SO_PARTIAL) {
4333                 for_each_node_state(node, N_NORMAL_MEMORY) {
4334                         struct kmem_cache_node *n = get_node(s, node);
4335 
4336                         if (flags & SO_TOTAL)
4337                                 x = count_partial(n, count_total);
4338                         else if (flags & SO_OBJECTS)
4339                                 x = count_partial(n, count_inuse);
4340                         else
4341                                 x = n->nr_partial;
4342                         total += x;
4343                         nodes[node] += x;
4344                 }
4345         }
4346         x = sprintf(buf, "%lu", total);
4347 #ifdef CONFIG_NUMA
4348         for_each_node_state(node, N_NORMAL_MEMORY)
4349                 if (nodes[node])
4350                         x += sprintf(buf + x, " N%d=%lu",
4351                                         node, nodes[node]);
4352 #endif
4353         unlock_memory_hotplug();
4354         kfree(nodes);
4355         return x + sprintf(buf + x, "\n");
4356 }
4357 
4358 #ifdef CONFIG_SLUB_DEBUG
4359 static int any_slab_objects(struct kmem_cache *s)
4360 {
4361         int node;
4362 
4363         for_each_online_node(node) {
4364                 struct kmem_cache_node *n = get_node(s, node);
4365 
4366                 if (!n)
4367                         continue;
4368 
4369                 if (atomic_long_read(&n->total_objects))
4370                         return 1;
4371         }
4372         return 0;
4373 }
4374 #endif
4375 
4376 #define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4377 #define to_slab(n) container_of(n, struct kmem_cache, kobj)
4378 
4379 struct slab_attribute {
4380         struct attribute attr;
4381         ssize_t (*show)(struct kmem_cache *s, char *buf);
4382         ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4383 };
4384 
4385 #define SLAB_ATTR_RO(_name) \
4386         static struct slab_attribute _name##_attr = \
4387         __ATTR(_name, 0400, _name##_show, NULL)
4388 
4389 #define SLAB_ATTR(_name) \
4390         static struct slab_attribute _name##_attr =  \
4391         __ATTR(_name, 0600, _name##_show, _name##_store)
4392 
4393 static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4394 {
4395         return sprintf(buf, "%d\n", s->size);
4396 }
4397 SLAB_ATTR_RO(slab_size);
4398 
4399 static ssize_t align_show(struct kmem_cache *s, char *buf)
4400 {
4401         return sprintf(buf, "%d\n", s->align);
4402 }
4403 SLAB_ATTR_RO(align);
4404 
4405 static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4406 {
4407         return sprintf(buf, "%d\n", s->object_size);
4408 }
4409 SLAB_ATTR_RO(object_size);
4410 
4411 static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4412 {
4413         return sprintf(buf, "%d\n", oo_objects(s->oo));
4414 }
4415 SLAB_ATTR_RO(objs_per_slab);
4416 
4417 static ssize_t order_store(struct kmem_cache *s,
4418                                 const char *buf, size_t length)
4419 {
4420         unsigned long order;
4421         int err;
4422 
4423         err = strict_strtoul(buf, 10, &order);
4424         if (err)
4425                 return err;
4426 
4427         if (order > slub_max_order || order < slub_min_order)
4428                 return -EINVAL;
4429 
4430         calculate_sizes(s, order);
4431         return length;
4432 }
4433 
4434 static ssize_t order_show(struct kmem_cache *s, char *buf)
4435 {
4436         return sprintf(buf, "%d\n", oo_order(s->oo));
4437 }
4438 SLAB_ATTR(order);
4439 
4440 static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4441 {
4442         return sprintf(buf, "%lu\n", s->min_partial);
4443 }
4444 
4445 static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4446                                  size_t length)
4447 {
4448         unsigned long min;
4449         int err;
4450 
4451         err = strict_strtoul(buf, 10, &min);
4452         if (err)
4453                 return err;
4454 
4455         set_min_partial(s, min);
4456         return length;
4457 }
4458 SLAB_ATTR(min_partial);
4459 
4460 static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4461 {
4462         return sprintf(buf, "%u\n", s->cpu_partial);
4463 }
4464 
4465 static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4466                                  size_t length)
4467 {
4468         unsigned long objects;
4469         int err;
4470 
4471         err = strict_strtoul(buf, 10, &objects);
4472         if (err)
4473                 return err;
4474         if (objects && !kmem_cache_has_cpu_partial(s))
4475                 return -EINVAL;
4476 
4477         s->cpu_partial = objects;
4478         flush_all(s);
4479         return length;
4480 }
4481 SLAB_ATTR(cpu_partial);
4482 
4483 static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4484 {
4485         if (!s->ctor)
4486                 return 0;
4487         return sprintf(buf, "%pS\n", s->ctor);
4488 }
4489 SLAB_ATTR_RO(ctor);
4490 
4491 static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4492 {
4493         return sprintf(buf, "%d\n", s->refcount - 1);
4494 }
4495 SLAB_ATTR_RO(aliases);
4496 
4497 static ssize_t partial_show(struct kmem_cache *s, char *buf)
4498 {
4499         return show_slab_objects(s, buf, SO_PARTIAL);
4500 }
4501 SLAB_ATTR_RO(partial);
4502 
4503 static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4504 {
4505         return show_slab_objects(s, buf, SO_CPU);
4506 }
4507 SLAB_ATTR_RO(cpu_slabs);
4508 
4509 static ssize_t objects_show(struct kmem_cache *s, char *buf)
4510 {
4511         return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4512 }
4513 SLAB_ATTR_RO(objects);
4514 
4515 static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4516 {
4517         return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4518 }
4519 SLAB_ATTR_RO(objects_partial);
4520 
4521 static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4522 {
4523         int objects = 0;
4524         int pages = 0;
4525         int cpu;
4526         int len;
4527 
4528         for_each_online_cpu(cpu) {
4529                 struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4530 
4531                 if (page) {
4532                         pages += page->pages;
4533                         objects += page->pobjects;
4534                 }
4535         }
4536 
4537         len = sprintf(buf, "%d(%d)", objects, pages);
4538 
4539 #ifdef CONFIG_SMP
4540         for_each_online_cpu(cpu) {
4541                 struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4542 
4543                 if (page && len < PAGE_SIZE - 20)
4544                         len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4545                                 page->pobjects, page->pages);
4546         }
4547 #endif
4548         return len + sprintf(buf + len, "\n");
4549 }
4550 SLAB_ATTR_RO(slabs_cpu_partial);
4551 
4552 static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4553 {
4554         return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4555 }
4556 
4557 static ssize_t reclaim_account_store(struct kmem_cache *s,
4558                                 const char *buf, size_t length)
4559 {
4560         s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4561         if (buf[0] == '1')
4562                 s->flags |= SLAB_RECLAIM_ACCOUNT;
4563         return length;
4564 }
4565 SLAB_ATTR(reclaim_account);
4566 
4567 static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4568 {
4569         return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4570 }
4571 SLAB_ATTR_RO(hwcache_align);
4572 
4573 #ifdef CONFIG_ZONE_DMA
4574 static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4575 {
4576         return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4577 }
4578 SLAB_ATTR_RO(cache_dma);
4579 #endif
4580 
4581 static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
4582 {
4583         return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4584 }
4585 SLAB_ATTR_RO(destroy_by_rcu);
4586 
4587 static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4588 {
4589         return sprintf(buf, "%d\n", s->reserved);
4590 }
4591 SLAB_ATTR_RO(reserved);
4592 
4593 #ifdef CONFIG_SLUB_DEBUG
4594 static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4595 {
4596         return show_slab_objects(s, buf, SO_ALL);
4597 }
4598 SLAB_ATTR_RO(slabs);
4599 
4600 static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4601 {
4602         return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4603 }
4604 SLAB_ATTR_RO(total_objects);
4605 
4606 static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4607 {
4608         return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4609 }
4610 
4611 static ssize_t sanity_checks_store(struct kmem_cache *s,
4612                                 const char *buf, size_t length)
4613 {
4614         s->flags &= ~SLAB_DEBUG_FREE;
4615         if (buf[0] == '1') {
4616                 s->flags &= ~__CMPXCHG_DOUBLE;
4617                 s->flags |= SLAB_DEBUG_FREE;
4618         }
4619         return length;
4620 }
4621 SLAB_ATTR(sanity_checks);
4622 
4623 static ssize_t trace_show(struct kmem_cache *s, char *buf)
4624 {
4625         return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4626 }
4627 
4628 static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4629                                                         size_t length)
4630 {
4631         s->flags &= ~SLAB_TRACE;
4632         if (buf[0] == '1') {
4633                 s->flags &= ~__CMPXCHG_DOUBLE;
4634                 s->flags |= SLAB_TRACE;
4635         }
4636         return length;
4637 }
4638 SLAB_ATTR(trace);
4639 
4640 static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4641 {
4642         return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4643 }
4644 
4645 static ssize_t red_zone_store(struct kmem_cache *s,
4646                                 const char *buf, size_t length)
4647 {
4648         if (any_slab_objects(s))
4649                 return -EBUSY;
4650 
4651         s->flags &= ~SLAB_RED_ZONE;
4652         if (buf[0] == '1') {
4653                 s->flags &= ~__CMPXCHG_DOUBLE;
4654                 s->flags |= SLAB_RED_ZONE;
4655         }
4656         calculate_sizes(s, -1);
4657         return length;
4658 }
4659 SLAB_ATTR(red_zone);
4660 
4661 static ssize_t poison_show(struct kmem_cache *s, char *buf)
4662 {
4663         return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4664 }
4665 
4666 static ssize_t poison_store(struct kmem_cache *s,
4667                                 const char *buf, size_t length)
4668 {
4669         if (any_slab_objects(s))
4670                 return -EBUSY;
4671 
4672         s->flags &= ~SLAB_POISON;
4673         if (buf[0] == '1') {
4674                 s->flags &= ~__CMPXCHG_DOUBLE;
4675                 s->flags |= SLAB_POISON;
4676         }
4677         calculate_sizes(s, -1);
4678         return length;
4679 }
4680 SLAB_ATTR(poison);
4681 
4682 static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4683 {
4684         return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4685 }
4686 
4687 static ssize_t store_user_store(struct kmem_cache *s,
4688                                 const char *buf, size_t length)
4689 {
4690         if (any_slab_objects(s))
4691                 return -EBUSY;
4692 
4693         s->flags &= ~SLAB_STORE_USER;
4694         if (buf[0] == '1') {
4695                 s->flags &= ~__CMPXCHG_DOUBLE;
4696                 s->flags |= SLAB_STORE_USER;
4697         }
4698         calculate_sizes(s, -1);
4699         return length;
4700 }
4701 SLAB_ATTR(store_user);
4702 
4703 static ssize_t validate_show(struct kmem_cache *s, char *buf)
4704 {
4705         return 0;
4706 }
4707 
4708 static ssize_t validate_store(struct kmem_cache *s,
4709                         const char *buf, size_t length)
4710 {
4711         int ret = -EINVAL;
4712 
4713         if (buf[0] == '1') {
4714                 ret = validate_slab_cache(s);
4715                 if (ret >= 0)
4716                         ret = length;
4717         }
4718         return ret;
4719 }
4720 SLAB_ATTR(validate);
4721 
4722 static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4723 {
4724         if (!(s->flags & SLAB_STORE_USER))
4725                 return -ENOSYS;
4726         return list_locations(s, buf, TRACK_ALLOC);
4727 }
4728 SLAB_ATTR_RO(alloc_calls);
4729 
4730 static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4731 {
4732         if (!(s->flags & SLAB_STORE_USER))
4733                 return -ENOSYS;
4734         return list_locations(s, buf, TRACK_FREE);
4735 }
4736 SLAB_ATTR_RO(free_calls);
4737 #endif /* CONFIG_SLUB_DEBUG */
4738 
4739 #ifdef CONFIG_FAILSLAB
4740 static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4741 {
4742         return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4743 }
4744 
4745 static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4746                                                         size_t length)
4747 {
4748         s->flags &= ~SLAB_FAILSLAB;
4749         if (buf[0] == '1')
4750                 s->flags |= SLAB_FAILSLAB;
4751         return length;
4752 }
4753 SLAB_ATTR(failslab);
4754 #endif
4755 
4756 static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4757 {
4758         return 0;
4759 }
4760 
4761 static ssize_t shrink_store(struct kmem_cache *s,
4762                         const char *buf, size_t length)
4763 {
4764         if (buf[0] == '1') {
4765                 int rc = kmem_cache_shrink(s);
4766 
4767                 if (rc)
4768                         return rc;
4769         } else
4770                 return -EINVAL;
4771         return length;
4772 }
4773 SLAB_ATTR(shrink);
4774 
4775 #ifdef CONFIG_NUMA
4776 static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4777 {
4778         return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4779 }
4780 
4781 static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
4782                                 const char *buf, size_t length)
4783 {
4784         unsigned long ratio;
4785         int err;
4786 
4787         err = strict_strtoul(buf, 10, &ratio);
4788         if (err)
4789                 return err;
4790 
4791         if (ratio <= 100)
4792                 s->remote_node_defrag_ratio = ratio * 10;
4793 
4794         return length;
4795 }
4796 SLAB_ATTR(remote_node_defrag_ratio);
4797 #endif
4798 
4799 #ifdef CONFIG_SLUB_STATS
4800 static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
4801 {
4802         unsigned long sum  = 0;
4803         int cpu;
4804         int len;
4805         int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
4806 
4807         if (!data)
4808                 return -ENOMEM;
4809 
4810         for_each_online_cpu(cpu) {
4811                 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
4812 
4813                 data[cpu] = x;
4814                 sum += x;
4815         }
4816 
4817         len = sprintf(buf, "%lu", sum);
4818 
4819 #ifdef CONFIG_SMP
4820         for_each_online_cpu(cpu) {
4821                 if (data[cpu] && len < PAGE_SIZE - 20)
4822                         len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
4823         }
4824 #endif
4825         kfree(data);
4826         return len + sprintf(buf + len, "\n");
4827 }
4828 
4829 static void clear_stat(struct kmem_cache *s, enum stat_item si)
4830 {
4831         int cpu;
4832 
4833         for_each_online_cpu(cpu)
4834                 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
4835 }
4836 
4837 #define STAT_ATTR(si, text)                                     \
4838 static ssize_t text##_show(struct kmem_cache *s, char *buf)     \
4839 {                                                               \
4840         return show_stat(s, buf, si);                           \
4841 }                                                               \
4842 static ssize_t text##_store(struct kmem_cache *s,               \
4843                                 const char *buf, size_t length) \
4844 {                                                               \
4845         if (buf[0] != '')                                      \
4846                 return -EINVAL;                                 \
4847         clear_stat(s, si);                                      \
4848         return length;                                          \
4849 }                                                               \
4850 SLAB_ATTR(text);                                                \
4851 
4852 STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
4853 STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
4854 STAT_ATTR(FREE_FASTPATH, free_fastpath);
4855 STAT_ATTR(FREE_SLOWPATH, free_slowpath);
4856 STAT_ATTR(FREE_FROZEN, free_frozen);
4857 STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
4858 STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
4859 STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
4860 STAT_ATTR(ALLOC_SLAB, alloc_slab);
4861 STAT_ATTR(ALLOC_REFILL, alloc_refill);
4862 STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
4863 STAT_ATTR(FREE_SLAB, free_slab);
4864 STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
4865 STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
4866 STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
4867 STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
4868 STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
4869 STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
4870 STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
4871 STAT_ATTR(ORDER_FALLBACK, order_fallback);
4872 STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
4873 STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
4874 STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
4875 STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
4876 STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
4877 STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
4878 #endif
4879 
4880 static struct attribute *slab_attrs[] = {
4881         &slab_size_attr.attr,
4882         &object_size_attr.attr,
4883         &objs_per_slab_attr.attr,
4884         &order_attr.attr,
4885         &min_partial_attr.attr,
4886         &cpu_partial_attr.attr,
4887         &objects_attr.attr,
4888         &objects_partial_attr.attr,
4889         &partial_attr.attr,
4890         &cpu_slabs_attr.attr,
4891         &ctor_attr.attr,
4892         &aliases_attr.attr,
4893         &align_attr.attr,
4894         &hwcache_align_attr.attr,
4895         &reclaim_account_attr.attr,
4896         &destroy_by_rcu_attr.attr,
4897         &shrink_attr.attr,
4898         &reserved_attr.attr,
4899         &slabs_cpu_partial_attr.attr,
4900 #ifdef CONFIG_SLUB_DEBUG
4901         &total_objects_attr.attr,
4902         &slabs_attr.attr,
4903         &sanity_checks_attr.attr,
4904         &trace_attr.attr,
4905         &red_zone_attr.attr,
4906         &poison_attr.attr,
4907         &store_user_attr.attr,
4908         &validate_attr.attr,
4909         &alloc_calls_attr.attr,
4910         &free_calls_attr.attr,
4911 #endif
4912 #ifdef CONFIG_ZONE_DMA
4913         &cache_dma_attr.attr,
4914 #endif
4915 #ifdef CONFIG_NUMA
4916         &remote_node_defrag_ratio_attr.attr,
4917 #endif
4918 #ifdef CONFIG_SLUB_STATS
4919         &alloc_fastpath_attr.attr,
4920         &alloc_slowpath_attr.attr,
4921         &free_fastpath_attr.attr,
4922         &free_slowpath_attr.attr,
4923         &free_frozen_attr.attr,
4924         &free_add_partial_attr.attr,
4925         &free_remove_partial_attr.attr,
4926         &alloc_from_partial_attr.attr,
4927         &alloc_slab_attr.attr,
4928         &alloc_refill_attr.attr,
4929         &alloc_node_mismatch_attr.attr,
4930         &free_slab_attr.attr,
4931         &cpuslab_flush_attr.attr,
4932         &deactivate_full_attr.attr,
4933         &deactivate_empty_attr.attr,
4934         &deactivate_to_head_attr.attr,
4935         &deactivate_to_tail_attr.attr,
4936         &deactivate_remote_frees_attr.attr,
4937         &deactivate_bypass_attr.attr,
4938         &order_fallback_attr.attr,
4939         &cmpxchg_double_fail_attr.attr,
4940         &cmpxchg_double_cpu_fail_attr.attr,
4941         &cpu_partial_alloc_attr.attr,
4942         &cpu_partial_free_attr.attr,
4943         &cpu_partial_node_attr.attr,
4944         &cpu_partial_drain_attr.attr,
4945 #endif
4946 #ifdef CONFIG_FAILSLAB
4947         &failslab_attr.attr,
4948 #endif
4949 
4950         NULL
4951 };
4952 
4953 static struct attribute_group slab_attr_group = {
4954         .attrs = slab_attrs,
4955 };
4956 
4957 static ssize_t slab_attr_show(struct kobject *kobj,
4958                                 struct attribute *attr,
4959                                 char *buf)
4960 {
4961         struct slab_attribute *attribute;
4962         struct kmem_cache *s;
4963         int err;
4964 
4965         attribute = to_slab_attr(attr);
4966         s = to_slab(kobj);
4967 
4968         if (!attribute->show)
4969                 return -EIO;
4970 
4971         err = attribute->show(s, buf);
4972 
4973         return err;
4974 }
4975 
4976 static ssize_t slab_attr_store(struct kobject *kobj,
4977                                 struct attribute *attr,
4978                                 const char *buf, size_t len)
4979 {
4980         struct slab_attribute *attribute;
4981         struct kmem_cache *s;
4982         int err;
4983 
4984         attribute = to_slab_attr(attr);
4985         s = to_slab(kobj);
4986 
4987         if (!attribute->store)
4988                 return -EIO;
4989 
4990         err = attribute->store(s, buf, len);
4991 #ifdef CONFIG_MEMCG_KMEM
4992         if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
4993                 int i;
4994 
4995                 mutex_lock(&slab_mutex);
4996                 if (s->max_attr_size < len)
4997                         s->max_attr_size = len;
4998 
4999                 /*
5000                  * This is a best effort propagation, so this function's return
5001                  * value will be determined by the parent cache only. This is
5002                  * basically because not all attributes will have a well
5003                  * defined semantics for rollbacks - most of the actions will
5004                  * have permanent effects.
5005                  *
5006                  * Returning the error value of any of the children that fail
5007                  * is not 100 % defined, in the sense that users seeing the
5008                  * error code won't be able to know anything about the state of
5009                  * the cache.
5010                  *
5011                  * Only returning the error code for the parent cache at least
5012                  * has well defined semantics. The cache being written to
5013                  * directly either failed or succeeded, in which case we loop
5014                  * through the descendants with best-effort propagation.
5015                  */
5016                 for_each_memcg_cache_index(i) {
5017                         struct kmem_cache *c = cache_from_memcg(s, i);
5018                         if (c)
5019                                 attribute->store(c, buf, len);
5020                 }
5021                 mutex_unlock(&slab_mutex);
5022         }
5023 #endif
5024         return err;
5025 }
5026 
5027 static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5028 {
5029 #ifdef CONFIG_MEMCG_KMEM
5030         int i;
5031         char *buffer = NULL;
5032 
5033         if (!is_root_cache(s))
5034                 return;
5035 
5036         /*
5037          * This mean this cache had no attribute written. Therefore, no point
5038          * in copying default values around
5039          */
5040         if (!s->max_attr_size)
5041                 return;
5042 
5043         for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5044                 char mbuf[64];
5045                 char *buf;
5046                 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5047 
5048                 if (!attr || !attr->store || !attr->show)
5049                         continue;
5050 
5051                 /*
5052                  * It is really bad that we have to allocate here, so we will
5053                  * do it only as a fallback. If we actually allocate, though,
5054                  * we can just use the allocated buffer until the end.
5055                  *
5056                  * Most of the slub attributes will tend to be very small in
5057                  * size, but sysfs allows buffers up to a page, so they can
5058                  * theoretically happen.
5059                  */
5060                 if (buffer)
5061                         buf = buffer;
5062                 else if (s->max_attr_size < ARRAY_SIZE(mbuf))
5063                         buf = mbuf;
5064                 else {
5065                         buffer = (char *) get_zeroed_page(GFP_KERNEL);
5066                         if (WARN_ON(!buffer))
5067                                 continue;
5068                         buf = buffer;
5069                 }
5070 
5071                 attr->show(s->memcg_params->root_cache, buf);
5072                 attr->store(s, buf, strlen(buf));
5073         }
5074 
5075         if (buffer)
5076                 free_page((unsigned long)buffer);
5077 #endif
5078 }
5079 
5080 static const struct sysfs_ops slab_sysfs_ops = {
5081         .show = slab_attr_show,
5082         .store = slab_attr_store,
5083 };
5084 
5085 static struct kobj_type slab_ktype = {
5086         .sysfs_ops = &slab_sysfs_ops,
5087 };
5088 
5089 static int uevent_filter(struct kset *kset, struct kobject *kobj)
5090 {
5091         struct kobj_type *ktype = get_ktype(kobj);
5092 
5093         if (ktype == &slab_ktype)
5094                 return 1;
5095         return 0;
5096 }
5097 
5098 static const struct kset_uevent_ops slab_uevent_ops = {
5099         .filter = uevent_filter,
5100 };
5101 
5102 static struct kset *slab_kset;
5103 
5104 #define ID_STR_LENGTH 64
5105 
5106 /* Create a unique string id for a slab cache:
5107  *
5108  * Format       :[flags-]size
5109  */
5110 static char *create_unique_id(struct kmem_cache *s)
5111 {
5112         char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5113         char *p = name;
5114 
5115         BUG_ON(!name);
5116 
5117         *p++ = ':';
5118         /*
5119          * First flags affecting slabcache operations. We will only
5120          * get here for aliasable slabs so we do not need to support
5121          * too many flags. The flags here must cover all flags that
5122          * are matched during merging to guarantee that the id is
5123          * unique.
5124          */
5125         if (s->flags & SLAB_CACHE_DMA)
5126                 *p++ = 'd';
5127         if (s->flags & SLAB_RECLAIM_ACCOUNT)
5128                 *p++ = 'a';
5129         if (s->flags & SLAB_DEBUG_FREE)
5130                 *p++ = 'F';
5131         if (!(s->flags & SLAB_NOTRACK))
5132                 *p++ = 't';
5133         if (p != name + 1)
5134                 *p++ = '-';
5135         p += sprintf(p, "%07d", s->size);
5136 
5137 #ifdef CONFIG_MEMCG_KMEM
5138         if (!is_root_cache(s))
5139                 p += sprintf(p, "-%08d", memcg_cache_id(s->memcg_params->memcg));
5140 #endif
5141 
5142         BUG_ON(p > name + ID_STR_LENGTH - 1);
5143         return name;
5144 }
5145 
5146 static int sysfs_slab_add(struct kmem_cache *s)
5147 {
5148         int err;
5149         const char *name;
5150         int unmergeable = slab_unmergeable(s);
5151 
5152         if (unmergeable) {
5153                 /*
5154                  * Slabcache can never be merged so we can use the name proper.
5155                  * This is typically the case for debug situations. In that
5156                  * case we can catch duplicate names easily.
5157                  */
5158                 sysfs_remove_link(&slab_kset->kobj, s->name);
5159                 name = s->name;
5160         } else {
5161                 /*
5162                  * Create a unique name for the slab as a target
5163                  * for the symlinks.
5164                  */
5165                 name = create_unique_id(s);
5166         }
5167 
5168         s->kobj.kset = slab_kset;
5169         err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
5170         if (err) {
5171                 kobject_put(&s->kobj);
5172                 return err;
5173         }
5174 
5175         err = sysfs_create_group(&s->kobj, &slab_attr_group);
5176         if (err) {
5177                 kobject_del(&s->kobj);
5178                 kobject_put(&s->kobj);
5179                 return err;
5180         }
5181         kobject_uevent(&s->kobj, KOBJ_ADD);
5182         if (!unmergeable) {
5183                 /* Setup first alias */
5184                 sysfs_slab_alias(s, s->name);
5185                 kfree(name);
5186         }
5187         return 0;
5188 }
5189 
5190 static void sysfs_slab_remove(struct kmem_cache *s)
5191 {
5192         if (slab_state < FULL)
5193                 /*
5194                  * Sysfs has not been setup yet so no need to remove the
5195                  * cache from sysfs.
5196                  */
5197                 return;
5198 
5199         kobject_uevent(&s->kobj, KOBJ_REMOVE);
5200         kobject_del(&s->kobj);
5201         kobject_put(&s->kobj);
5202 }
5203 
5204 /*
5205  * Need to buffer aliases during bootup until sysfs becomes
5206  * available lest we lose that information.
5207  */
5208 struct saved_alias {
5209         struct kmem_cache *s;
5210         const char *name;
5211         struct saved_alias *next;
5212 };
5213 
5214 static struct saved_alias *alias_list;
5215 
5216 static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5217 {
5218         struct saved_alias *al;
5219 
5220         if (slab_state == FULL) {
5221                 /*
5222                  * If we have a leftover link then remove it.
5223                  */
5224                 sysfs_remove_link(&slab_kset->kobj, name);
5225                 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5226         }
5227 
5228         al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5229         if (!al)
5230                 return -ENOMEM;
5231 
5232         al->s = s;
5233         al->name = name;
5234         al->next = alias_list;
5235         alias_list = al;
5236         return 0;
5237 }
5238 
5239 static int __init slab_sysfs_init(void)
5240 {
5241         struct kmem_cache *s;
5242         int err;
5243 
5244         mutex_lock(&slab_mutex);
5245 
5246         slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5247         if (!slab_kset) {
5248                 mutex_unlock(&slab_mutex);
5249                 printk(KERN_ERR "Cannot register slab subsystem.\n");
5250                 return -ENOSYS;
5251         }
5252 
5253         slab_state = FULL;
5254 
5255         list_for_each_entry(s, &slab_caches, list) {
5256                 err = sysfs_slab_add(s);
5257                 if (err)
5258                         printk(KERN_ERR "SLUB: Unable to add boot slab %s"
5259                                                 " to sysfs\n", s->name);
5260         }
5261 
5262         while (alias_list) {
5263                 struct saved_alias *al = alias_list;
5264 
5265                 alias_list = alias_list->next;
5266                 err = sysfs_slab_alias(al->s, al->name);
5267                 if (err)
5268                         printk(KERN_ERR "SLUB: Unable to add boot slab alias"
5269                                         " %s to sysfs\n", al->name);
5270                 kfree(al);
5271         }
5272 
5273         mutex_unlock(&slab_mutex);
5274         resiliency_test();
5275         return 0;
5276 }
5277 
5278 __initcall(slab_sysfs_init);
5279 #endif /* CONFIG_SYSFS */
5280 
5281 /*
5282  * The /proc/slabinfo ABI
5283  */
5284 #ifdef CONFIG_SLABINFO
5285 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5286 {
5287         unsigned long nr_slabs = 0;
5288         unsigned long nr_objs = 0;
5289         unsigned long nr_free = 0;
5290         int node;
5291 
5292         for_each_online_node(node) {
5293                 struct kmem_cache_node *n = get_node(s, node);
5294 
5295                 if (!n)
5296                         continue;
5297 
5298                 nr_slabs += node_nr_slabs(n);
5299                 nr_objs += node_nr_objs(n);
5300                 nr_free += count_partial(n, count_free);
5301         }
5302 
5303         sinfo->active_objs = nr_objs - nr_free;
5304         sinfo->num_objs = nr_objs;
5305         sinfo->active_slabs = nr_slabs;
5306         sinfo->num_slabs = nr_slabs;
5307         sinfo->objects_per_slab = oo_objects(s->oo);
5308         sinfo->cache_order = oo_order(s->oo);
5309 }
5310 
5311 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5312 {
5313 }
5314 
5315 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5316                        size_t count, loff_t *ppos)
5317 {
5318         return -EIO;
5319 }
5320 #endif /* CONFIG_SLABINFO */
5321 

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