slub.c 115 KB
Newer Older
Christoph Lameter's avatar
Christoph Lameter committed
1
2
3
4
5
6
7
/*
 * SLUB: A slab allocator that limits cache line use instead of queuing
 * objects in per cpu and per node lists.
 *
 * The allocator synchronizes using per slab locks and only
 * uses a centralized lock to manage a pool of partial slabs.
 *
Christoph Lameter's avatar
Christoph Lameter committed
8
 * (C) 2007 SGI, Christoph Lameter
Christoph Lameter's avatar
Christoph Lameter committed
9
10
11
 */

#include <linux/mm.h>
Nick Piggin's avatar
Nick Piggin committed
12
#include <linux/swap.h> /* struct reclaim_state */
Christoph Lameter's avatar
Christoph Lameter committed
13
14
15
16
17
#include <linux/module.h>
#include <linux/bit_spinlock.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/slab.h>
18
#include <linux/proc_fs.h>
Christoph Lameter's avatar
Christoph Lameter committed
19
#include <linux/seq_file.h>
Vegard Nossum's avatar
Vegard Nossum committed
20
#include <linux/kmemcheck.h>
Christoph Lameter's avatar
Christoph Lameter committed
21
22
23
24
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/mempolicy.h>
#include <linux/ctype.h>
25
#include <linux/debugobjects.h>
Christoph Lameter's avatar
Christoph Lameter committed
26
#include <linux/kallsyms.h>
27
#include <linux/memory.h>
Roman Zippel's avatar
Roman Zippel committed
28
#include <linux/math64.h>
Akinobu Mita's avatar
Akinobu Mita committed
29
#include <linux/fault-inject.h>
Christoph Lameter's avatar
Christoph Lameter committed
30

31
32
#include <trace/events/kmem.h>

Christoph Lameter's avatar
Christoph Lameter committed
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
/*
 * Lock order:
 *   1. slab_lock(page)
 *   2. slab->list_lock
 *
 *   The slab_lock protects operations on the object of a particular
 *   slab and its metadata in the page struct. If the slab lock
 *   has been taken then no allocations nor frees can be performed
 *   on the objects in the slab nor can the slab be added or removed
 *   from the partial or full lists since this would mean modifying
 *   the page_struct of the slab.
 *
 *   The list_lock protects the partial and full list on each node and
 *   the partial slab counter. If taken then no new slabs may be added or
 *   removed from the lists nor make the number of partial slabs be modified.
 *   (Note that the total number of slabs is an atomic value that may be
 *   modified without taking the list lock).
 *
 *   The list_lock is a centralized lock and thus we avoid taking it as
 *   much as possible. As long as SLUB does not have to handle partial
 *   slabs, operations can continue without any centralized lock. F.e.
 *   allocating a long series of objects that fill up slabs does not require
 *   the list lock.
 *
 *   The lock order is sometimes inverted when we are trying to get a slab
 *   off a list. We take the list_lock and then look for a page on the list
 *   to use. While we do that objects in the slabs may be freed. We can
 *   only operate on the slab if we have also taken the slab_lock. So we use
 *   a slab_trylock() on the slab. If trylock was successful then no frees
 *   can occur anymore and we can use the slab for allocations etc. If the
 *   slab_trylock() does not succeed then frees are in progress in the slab and
 *   we must stay away from it for a while since we may cause a bouncing
 *   cacheline if we try to acquire the lock. So go onto the next slab.
 *   If all pages are busy then we may allocate a new slab instead of reusing
 *   a partial slab. A new slab has noone operating on it and thus there is
 *   no danger of cacheline contention.
 *
 *   Interrupts are disabled during allocation and deallocation in order to
 *   make the slab allocator safe to use in the context of an irq. In addition
 *   interrupts are disabled to ensure that the processor does not change
 *   while handling per_cpu slabs, due to kernel preemption.
 *
 * SLUB assigns one slab for allocation to each processor.
 * Allocations only occur from these slabs called cpu slabs.
 *
Christoph Lameter's avatar
Christoph Lameter committed
78
79
 * Slabs with free elements are kept on a partial list and during regular
 * operations no list for full slabs is used. If an object in a full slab is
Christoph Lameter's avatar
Christoph Lameter committed
80
 * freed then the slab will show up again on the partial lists.
Christoph Lameter's avatar
Christoph Lameter committed
81
82
 * We track full slabs for debugging purposes though because otherwise we
 * cannot scan all objects.
Christoph Lameter's avatar
Christoph Lameter committed
83
84
85
86
87
88
89
 *
 * Slabs are freed when they become empty. Teardown and setup is
 * minimal so we rely on the page allocators per cpu caches for
 * fast frees and allocs.
 *
 * Overloading of page flags that are otherwise used for LRU management.
 *
90
91
92
93
94
95
96
97
98
99
100
101
 * PageActive 		The slab is frozen and exempt from list processing.
 * 			This means that the slab is dedicated to a purpose
 * 			such as satisfying allocations for a specific
 * 			processor. Objects may be freed in the slab while
 * 			it is frozen but slab_free will then skip the usual
 * 			list operations. It is up to the processor holding
 * 			the slab to integrate the slab into the slab lists
 * 			when the slab is no longer needed.
 *
 * 			One use of this flag is to mark slabs that are
 * 			used for allocations. Then such a slab becomes a cpu
 * 			slab. The cpu slab may be equipped with an additional
102
 * 			freelist that allows lockless access to
103
104
 * 			free objects in addition to the regular freelist
 * 			that requires the slab lock.
Christoph Lameter's avatar
Christoph Lameter committed
105
106
107
 *
 * PageError		Slab requires special handling due to debug
 * 			options set. This moves	slab handling out of
108
 * 			the fast path and disables lockless freelists.
Christoph Lameter's avatar
Christoph Lameter committed
109
110
 */

111
112
113
114
115
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
		SLAB_TRACE | SLAB_DEBUG_FREE)

static inline int kmem_cache_debug(struct kmem_cache *s)
{
116
#ifdef CONFIG_SLUB_DEBUG
117
	return unlikely(s->flags & SLAB_DEBUG_FLAGS);
118
#else
119
	return 0;
120
#endif
121
}
122

Christoph Lameter's avatar
Christoph Lameter committed
123
124
125
126
127
128
129
130
131
132
133
/*
 * Issues still to be resolved:
 *
 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
 *
 * - Variable sizing of the per node arrays
 */

/* Enable to test recovery from slab corruption on boot */
#undef SLUB_RESILIENCY_TEST

134
135
136
137
/*
 * Mininum number of partial slabs. These will be left on the partial
 * lists even if they are empty. kmem_cache_shrink may reclaim them.
 */
138
#define MIN_PARTIAL 5
Christoph Lameter's avatar
Christoph Lameter committed
139

140
141
142
143
144
145
146
/*
 * Maximum number of desirable partial slabs.
 * The existence of more partial slabs makes kmem_cache_shrink
 * sort the partial list by the number of objects in the.
 */
#define MAX_PARTIAL 10

Christoph Lameter's avatar
Christoph Lameter committed
147
148
#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
				SLAB_POISON | SLAB_STORE_USER)
Christoph Lameter's avatar
Christoph Lameter committed
149

150
/*
151
152
153
 * Debugging flags that require metadata to be stored in the slab.  These get
 * disabled when slub_debug=O is used and a cache's min order increases with
 * metadata.
154
 */
155
#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
156

Christoph Lameter's avatar
Christoph Lameter committed
157
158
159
160
/*
 * Set of flags that will prevent slab merging
 */
#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
161
162
		SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
		SLAB_FAILSLAB)
Christoph Lameter's avatar
Christoph Lameter committed
163
164

#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
Vegard Nossum's avatar
Vegard Nossum committed
165
		SLAB_CACHE_DMA | SLAB_NOTRACK)
Christoph Lameter's avatar
Christoph Lameter committed
166

167
168
169
170
#define OO_SHIFT	16
#define OO_MASK		((1 << OO_SHIFT) - 1)
#define MAX_OBJS_PER_PAGE	65535 /* since page.objects is u16 */

Christoph Lameter's avatar
Christoph Lameter committed
171
/* Internal SLUB flags */
Christoph Lameter's avatar
Christoph Lameter committed
172
#define __OBJECT_POISON		0x80000000UL /* Poison object */
Christoph Lameter's avatar
Christoph Lameter committed
173
174
175
176
177
178
179
180
181

static int kmem_size = sizeof(struct kmem_cache);

#ifdef CONFIG_SMP
static struct notifier_block slab_notifier;
#endif

static enum {
	DOWN,		/* No slab functionality available */
182
	PARTIAL,	/* Kmem_cache_node works */
Christoph Lameter's avatar
Christoph Lameter committed
183
	UP,		/* Everything works but does not show up in sysfs */
Christoph Lameter's avatar
Christoph Lameter committed
184
185
186
187
188
	SYSFS		/* Sysfs up */
} slab_state = DOWN;

/* A list of all slab caches on the system */
static DECLARE_RWSEM(slub_lock);
Adrian Bunk's avatar
Adrian Bunk committed
189
static LIST_HEAD(slab_caches);
Christoph Lameter's avatar
Christoph Lameter committed
190

191
192
193
194
/*
 * Tracking user of a slab.
 */
struct track {
195
	unsigned long addr;	/* Called from address */
196
197
198
199
200
201
202
	int cpu;		/* Was running on cpu */
	int pid;		/* Pid context */
	unsigned long when;	/* When did the operation occur */
};

enum track_item { TRACK_ALLOC, TRACK_FREE };

203
#ifdef CONFIG_SYSFS
Christoph Lameter's avatar
Christoph Lameter committed
204
205
206
static int sysfs_slab_add(struct kmem_cache *);
static int sysfs_slab_alias(struct kmem_cache *, const char *);
static void sysfs_slab_remove(struct kmem_cache *);
207

Christoph Lameter's avatar
Christoph Lameter committed
208
#else
209
210
211
static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
							{ return 0; }
212
213
static inline void sysfs_slab_remove(struct kmem_cache *s)
{
214
	kfree(s->name);
215
216
	kfree(s);
}
217

Christoph Lameter's avatar
Christoph Lameter committed
218
219
#endif

220
static inline void stat(const struct kmem_cache *s, enum stat_item si)
221
222
{
#ifdef CONFIG_SLUB_STATS
223
	__this_cpu_inc(s->cpu_slab->stat[si]);
224
225
226
#endif
}

Christoph Lameter's avatar
Christoph Lameter committed
227
228
229
230
231
232
233
234
235
236
237
238
239
240
/********************************************************************
 * 			Core slab cache functions
 *******************************************************************/

int slab_is_available(void)
{
	return slab_state >= UP;
}

static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
{
	return s->node[node];
}

Christoph Lameter's avatar
Christoph Lameter committed
241
/* Verify that a pointer has an address that is valid within a slab page */
242
243
244
245
246
static inline int check_valid_pointer(struct kmem_cache *s,
				struct page *page, const void *object)
{
	void *base;

247
	if (!object)
248
249
		return 1;

250
	base = page_address(page);
251
	if (object < base || object >= base + page->objects * s->size ||
252
253
254
255
256
257
258
		(object - base) % s->size) {
		return 0;
	}

	return 1;
}

259
260
261
262
263
264
265
266
267
268
269
static inline void *get_freepointer(struct kmem_cache *s, void *object)
{
	return *(void **)(object + s->offset);
}

static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
{
	*(void **)(object + s->offset) = fp;
}

/* Loop over all objects in a slab */
270
271
#define for_each_object(__p, __s, __addr, __objects) \
	for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
272
273
274
275
276
277
278
279
			__p += (__s)->size)

/* Determine object index from a given position */
static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
{
	return (p - addr) / s->size;
}

280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
static inline size_t slab_ksize(const struct kmem_cache *s)
{
#ifdef CONFIG_SLUB_DEBUG
	/*
	 * Debugging requires use of the padding between object
	 * and whatever may come after it.
	 */
	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
		return s->objsize;

#endif
	/*
	 * If we have the need to store the freelist pointer
	 * back there or track user information then we can
	 * only use the space before that information.
	 */
	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
		return s->inuse;
	/*
	 * Else we can use all the padding etc for the allocation
	 */
	return s->size;
}

304
305
306
307
308
static inline int order_objects(int order, unsigned long size, int reserved)
{
	return ((PAGE_SIZE << order) - reserved) / size;
}

309
static inline struct kmem_cache_order_objects oo_make(int order,
310
		unsigned long size, int reserved)
311
312
{
	struct kmem_cache_order_objects x = {
313
		(order << OO_SHIFT) + order_objects(order, size, reserved)
314
315
316
317
318
319
320
	};

	return x;
}

static inline int oo_order(struct kmem_cache_order_objects x)
{
321
	return x.x >> OO_SHIFT;
322
323
324
325
}

static inline int oo_objects(struct kmem_cache_order_objects x)
{
326
	return x.x & OO_MASK;
327
328
}

329
#ifdef CONFIG_SLUB_DEBUG
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
/*
 * Determine a map of object in use on a page.
 *
 * Slab lock or node listlock must be held to guarantee that the page does
 * not vanish from under us.
 */
static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
{
	void *p;
	void *addr = page_address(page);

	for (p = page->freelist; p; p = get_freepointer(s, p))
		set_bit(slab_index(p, s, addr), map);
}

345
346
347
/*
 * Debug settings:
 */
348
349
350
#ifdef CONFIG_SLUB_DEBUG_ON
static int slub_debug = DEBUG_DEFAULT_FLAGS;
#else
351
static int slub_debug;
352
#endif
353
354

static char *slub_debug_slabs;
355
static int disable_higher_order_debug;
356

Christoph Lameter's avatar
Christoph Lameter committed
357
358
359
360
361
362
363
364
365
366
367
368
369
/*
 * Object debugging
 */
static void print_section(char *text, u8 *addr, unsigned int length)
{
	int i, offset;
	int newline = 1;
	char ascii[17];

	ascii[16] = 0;

	for (i = 0; i < length; i++) {
		if (newline) {
370
			printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
Christoph Lameter's avatar
Christoph Lameter committed
371
372
			newline = 0;
		}
373
		printk(KERN_CONT " %02x", addr[i]);
Christoph Lameter's avatar
Christoph Lameter committed
374
375
376
		offset = i % 16;
		ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
		if (offset == 15) {
377
			printk(KERN_CONT " %s\n", ascii);
Christoph Lameter's avatar
Christoph Lameter committed
378
379
380
381
382
383
			newline = 1;
		}
	}
	if (!newline) {
		i %= 16;
		while (i < 16) {
384
			printk(KERN_CONT "   ");
Christoph Lameter's avatar
Christoph Lameter committed
385
386
387
			ascii[i] = ' ';
			i++;
		}
388
		printk(KERN_CONT " %s\n", ascii);
Christoph Lameter's avatar
Christoph Lameter committed
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
	}
}

static struct track *get_track(struct kmem_cache *s, void *object,
	enum track_item alloc)
{
	struct track *p;

	if (s->offset)
		p = object + s->offset + sizeof(void *);
	else
		p = object + s->inuse;

	return p + alloc;
}

static void set_track(struct kmem_cache *s, void *object,
406
			enum track_item alloc, unsigned long addr)
Christoph Lameter's avatar
Christoph Lameter committed
407
{
Akinobu Mita's avatar
Akinobu Mita committed
408
	struct track *p = get_track(s, object, alloc);
Christoph Lameter's avatar
Christoph Lameter committed
409
410
411
412

	if (addr) {
		p->addr = addr;
		p->cpu = smp_processor_id();
413
		p->pid = current->pid;
Christoph Lameter's avatar
Christoph Lameter committed
414
415
416
417
418
419
420
		p->when = jiffies;
	} else
		memset(p, 0, sizeof(struct track));
}

static void init_tracking(struct kmem_cache *s, void *object)
{
421
422
423
	if (!(s->flags & SLAB_STORE_USER))
		return;

424
425
	set_track(s, object, TRACK_FREE, 0UL);
	set_track(s, object, TRACK_ALLOC, 0UL);
Christoph Lameter's avatar
Christoph Lameter committed
426
427
428
429
430
431
432
}

static void print_track(const char *s, struct track *t)
{
	if (!t->addr)
		return;

433
	printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
434
		s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
435
436
437
438
439
440
441
442
443
444
445
446
447
}

static void print_tracking(struct kmem_cache *s, void *object)
{
	if (!(s->flags & SLAB_STORE_USER))
		return;

	print_track("Allocated", get_track(s, object, TRACK_ALLOC));
	print_track("Freed", get_track(s, object, TRACK_FREE));
}

static void print_page_info(struct page *page)
{
448
449
	printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
		page, page->objects, page->inuse, page->freelist, page->flags);
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465

}

static void slab_bug(struct kmem_cache *s, char *fmt, ...)
{
	va_list args;
	char buf[100];

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	printk(KERN_ERR "========================================"
			"=====================================\n");
	printk(KERN_ERR "BUG %s: %s\n", s->name, buf);
	printk(KERN_ERR "----------------------------------------"
			"-------------------------------------\n\n");
Christoph Lameter's avatar
Christoph Lameter committed
466
467
}

468
469
470
471
472
473
474
475
476
477
478
479
static void slab_fix(struct kmem_cache *s, char *fmt, ...)
{
	va_list args;
	char buf[100];

	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
	va_end(args);
	printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
}

static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
Christoph Lameter's avatar
Christoph Lameter committed
480
481
{
	unsigned int off;	/* Offset of last byte */
482
	u8 *addr = page_address(page);
483
484
485
486
487
488
489
490
491
492
493

	print_tracking(s, p);

	print_page_info(page);

	printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
			p, p - addr, get_freepointer(s, p));

	if (p > addr + 16)
		print_section("Bytes b4", p - 16, 16);

494
	print_section("Object", p, min_t(unsigned long, s->objsize, PAGE_SIZE));
Christoph Lameter's avatar
Christoph Lameter committed
495
496
497
498
499
500
501
502
503
504

	if (s->flags & SLAB_RED_ZONE)
		print_section("Redzone", p + s->objsize,
			s->inuse - s->objsize);

	if (s->offset)
		off = s->offset + sizeof(void *);
	else
		off = s->inuse;

505
	if (s->flags & SLAB_STORE_USER)
Christoph Lameter's avatar
Christoph Lameter committed
506
507
508
509
		off += 2 * sizeof(struct track);

	if (off != s->size)
		/* Beginning of the filler is the free pointer */
510
511
512
		print_section("Padding", p + off, s->size - off);

	dump_stack();
Christoph Lameter's avatar
Christoph Lameter committed
513
514
515
516
517
}

static void object_err(struct kmem_cache *s, struct page *page,
			u8 *object, char *reason)
{
518
	slab_bug(s, "%s", reason);
519
	print_trailer(s, page, object);
Christoph Lameter's avatar
Christoph Lameter committed
520
521
}

522
static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
Christoph Lameter's avatar
Christoph Lameter committed
523
524
525
526
{
	va_list args;
	char buf[100];

527
528
	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
Christoph Lameter's avatar
Christoph Lameter committed
529
	va_end(args);
530
	slab_bug(s, "%s", buf);
531
	print_page_info(page);
Christoph Lameter's avatar
Christoph Lameter committed
532
533
534
	dump_stack();
}

535
static void init_object(struct kmem_cache *s, void *object, u8 val)
Christoph Lameter's avatar
Christoph Lameter committed
536
537
538
539
540
{
	u8 *p = object;

	if (s->flags & __OBJECT_POISON) {
		memset(p, POISON_FREE, s->objsize - 1);
541
		p[s->objsize - 1] = POISON_END;
Christoph Lameter's avatar
Christoph Lameter committed
542
543
544
	}

	if (s->flags & SLAB_RED_ZONE)
545
		memset(p + s->objsize, val, s->inuse - s->objsize);
Christoph Lameter's avatar
Christoph Lameter committed
546
547
}

548
static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
Christoph Lameter's avatar
Christoph Lameter committed
549
550
551
{
	while (bytes) {
		if (*start != (u8)value)
552
			return start;
Christoph Lameter's avatar
Christoph Lameter committed
553
554
555
		start++;
		bytes--;
	}
556
557
558
559
560
561
562
563
564
565
566
567
	return NULL;
}

static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
						void *from, void *to)
{
	slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
	memset(from, data, to - from);
}

static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
			u8 *object, char *what,
568
			u8 *start, unsigned int value, unsigned int bytes)
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
{
	u8 *fault;
	u8 *end;

	fault = check_bytes(start, value, bytes);
	if (!fault)
		return 1;

	end = start + bytes;
	while (end > fault && end[-1] == value)
		end--;

	slab_bug(s, "%s overwritten", what);
	printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
					fault, end - 1, fault[0], value);
	print_trailer(s, page, object);

	restore_bytes(s, what, value, fault, end);
	return 0;
Christoph Lameter's avatar
Christoph Lameter committed
588
589
590
591
592
593
594
595
596
}

/*
 * Object layout:
 *
 * object address
 * 	Bytes of the object to be managed.
 * 	If the freepointer may overlay the object then the free
 * 	pointer is the first word of the object.
Christoph Lameter's avatar
Christoph Lameter committed
597
 *
Christoph Lameter's avatar
Christoph Lameter committed
598
599
600
601
602
 * 	Poisoning uses 0x6b (POISON_FREE) and the last byte is
 * 	0xa5 (POISON_END)
 *
 * object + s->objsize
 * 	Padding to reach word boundary. This is also used for Redzoning.
Christoph Lameter's avatar
Christoph Lameter committed
603
604
605
 * 	Padding is extended by another word if Redzoning is enabled and
 * 	objsize == inuse.
 *
Christoph Lameter's avatar
Christoph Lameter committed
606
607
608
609
 * 	We fill with 0xbb (RED_INACTIVE) for inactive objects and with
 * 	0xcc (RED_ACTIVE) for objects in use.
 *
 * object + s->inuse
Christoph Lameter's avatar
Christoph Lameter committed
610
611
 * 	Meta data starts here.
 *
Christoph Lameter's avatar
Christoph Lameter committed
612
613
 * 	A. Free pointer (if we cannot overwrite object on free)
 * 	B. Tracking data for SLAB_STORE_USER
Christoph Lameter's avatar
Christoph Lameter committed
614
 * 	C. Padding to reach required alignment boundary or at mininum
Christoph Lameter's avatar
Christoph Lameter committed
615
 * 		one word if debugging is on to be able to detect writes
Christoph Lameter's avatar
Christoph Lameter committed
616
617
618
 * 		before the word boundary.
 *
 *	Padding is done using 0x5a (POISON_INUSE)
Christoph Lameter's avatar
Christoph Lameter committed
619
620
 *
 * object + s->size
Christoph Lameter's avatar
Christoph Lameter committed
621
 * 	Nothing is used beyond s->size.
Christoph Lameter's avatar
Christoph Lameter committed
622
 *
Christoph Lameter's avatar
Christoph Lameter committed
623
624
 * If slabcaches are merged then the objsize and inuse boundaries are mostly
 * ignored. And therefore no slab options that rely on these boundaries
Christoph Lameter's avatar
Christoph Lameter committed
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
 * may be used with merged slabcaches.
 */

static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
{
	unsigned long off = s->inuse;	/* The end of info */

	if (s->offset)
		/* Freepointer is placed after the object. */
		off += sizeof(void *);

	if (s->flags & SLAB_STORE_USER)
		/* We also have user information there */
		off += 2 * sizeof(struct track);

	if (s->size == off)
		return 1;

643
644
	return check_bytes_and_report(s, page, p, "Object padding",
				p + off, POISON_INUSE, s->size - off);
Christoph Lameter's avatar
Christoph Lameter committed
645
646
}

647
/* Check the pad bytes at the end of a slab page */
Christoph Lameter's avatar
Christoph Lameter committed
648
649
static int slab_pad_check(struct kmem_cache *s, struct page *page)
{
650
651
652
653
654
	u8 *start;
	u8 *fault;
	u8 *end;
	int length;
	int remainder;
Christoph Lameter's avatar
Christoph Lameter committed
655
656
657
658

	if (!(s->flags & SLAB_POISON))
		return 1;

659
	start = page_address(page);
660
	length = (PAGE_SIZE << compound_order(page)) - s->reserved;
661
662
	end = start + length;
	remainder = length % s->size;
Christoph Lameter's avatar
Christoph Lameter committed
663
664
665
	if (!remainder)
		return 1;

666
	fault = check_bytes(end - remainder, POISON_INUSE, remainder);
667
668
669
670
671
672
	if (!fault)
		return 1;
	while (end > fault && end[-1] == POISON_INUSE)
		end--;

	slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
673
	print_section("Padding", end - remainder, remainder);
674

Eric Dumazet's avatar
Eric Dumazet committed
675
	restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
676
	return 0;
Christoph Lameter's avatar
Christoph Lameter committed
677
678
679
}

static int check_object(struct kmem_cache *s, struct page *page,
680
					void *object, u8 val)
Christoph Lameter's avatar
Christoph Lameter committed
681
682
683
684
685
{
	u8 *p = object;
	u8 *endobject = object + s->objsize;

	if (s->flags & SLAB_RED_ZONE) {
686
		if (!check_bytes_and_report(s, page, object, "Redzone",
687
			endobject, val, s->inuse - s->objsize))
Christoph Lameter's avatar
Christoph Lameter committed
688
689
			return 0;
	} else {
Ingo Molnar's avatar
Ingo Molnar committed
690
691
692
693
		if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
			check_bytes_and_report(s, page, p, "Alignment padding",
				endobject, POISON_INUSE, s->inuse - s->objsize);
		}
Christoph Lameter's avatar
Christoph Lameter committed
694
695
696
	}

	if (s->flags & SLAB_POISON) {
697
		if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
698
699
700
			(!check_bytes_and_report(s, page, p, "Poison", p,
					POISON_FREE, s->objsize - 1) ||
			 !check_bytes_and_report(s, page, p, "Poison",
701
				p + s->objsize - 1, POISON_END, 1)))
Christoph Lameter's avatar
Christoph Lameter committed
702
703
704
705
706
707
708
			return 0;
		/*
		 * check_pad_bytes cleans up on its own.
		 */
		check_pad_bytes(s, page, p);
	}

709
	if (!s->offset && val == SLUB_RED_ACTIVE)
Christoph Lameter's avatar
Christoph Lameter committed
710
711
712
713
714
715
716
717
718
719
		/*
		 * Object and freepointer overlap. Cannot check
		 * freepointer while object is allocated.
		 */
		return 1;

	/* Check free pointer validity */
	if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
		object_err(s, page, p, "Freepointer corrupt");
		/*
Nick Andrew's avatar
Nick Andrew committed
720
		 * No choice but to zap it and thus lose the remainder
Christoph Lameter's avatar
Christoph Lameter committed
721
		 * of the free objects in this slab. May cause
Christoph Lameter's avatar
Christoph Lameter committed
722
		 * another error because the object count is now wrong.
Christoph Lameter's avatar
Christoph Lameter committed
723
		 */
724
		set_freepointer(s, p, NULL);
Christoph Lameter's avatar
Christoph Lameter committed
725
726
727
728
729
730
731
		return 0;
	}
	return 1;
}

static int check_slab(struct kmem_cache *s, struct page *page)
{
732
733
	int maxobj;

Christoph Lameter's avatar
Christoph Lameter committed
734
735
736
	VM_BUG_ON(!irqs_disabled());

	if (!PageSlab(page)) {
737
		slab_err(s, page, "Not a valid slab page");
Christoph Lameter's avatar
Christoph Lameter committed
738
739
		return 0;
	}
740

741
	maxobj = order_objects(compound_order(page), s->size, s->reserved);
742
743
744
745
746
747
	if (page->objects > maxobj) {
		slab_err(s, page, "objects %u > max %u",
			s->name, page->objects, maxobj);
		return 0;
	}
	if (page->inuse > page->objects) {
748
		slab_err(s, page, "inuse %u > max %u",
749
			s->name, page->inuse, page->objects);
Christoph Lameter's avatar
Christoph Lameter committed
750
751
752
753
754
755
756
757
		return 0;
	}
	/* Slab_pad_check fixes things up after itself */
	slab_pad_check(s, page);
	return 1;
}

/*
Christoph Lameter's avatar
Christoph Lameter committed
758
759
 * Determine if a certain object on a page is on the freelist. Must hold the
 * slab lock to guarantee that the chains are in a consistent state.
Christoph Lameter's avatar
Christoph Lameter committed
760
761
762
763
764
765
 */
static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
{
	int nr = 0;
	void *fp = page->freelist;
	void *object = NULL;
766
	unsigned long max_objects;
Christoph Lameter's avatar
Christoph Lameter committed
767

768
	while (fp && nr <= page->objects) {
Christoph Lameter's avatar
Christoph Lameter committed
769
770
771
772
773
774
		if (fp == search)
			return 1;
		if (!check_valid_pointer(s, page, fp)) {
			if (object) {
				object_err(s, page, object,
					"Freechain corrupt");
775
				set_freepointer(s, object, NULL);
Christoph Lameter's avatar
Christoph Lameter committed
776
777
				break;
			} else {
778
				slab_err(s, page, "Freepointer corrupt");
779
				page->freelist = NULL;
780
				page->inuse = page->objects;
781
				slab_fix(s, "Freelist cleared");
Christoph Lameter's avatar
Christoph Lameter committed
782
783
784
785
786
787
788
789
790
				return 0;
			}
			break;
		}
		object = fp;
		fp = get_freepointer(s, object);
		nr++;
	}

791
	max_objects = order_objects(compound_order(page), s->size, s->reserved);
792
793
	if (max_objects > MAX_OBJS_PER_PAGE)
		max_objects = MAX_OBJS_PER_PAGE;
794
795
796
797
798
799
800

	if (page->objects != max_objects) {
		slab_err(s, page, "Wrong number of objects. Found %d but "
			"should be %d", page->objects, max_objects);
		page->objects = max_objects;
		slab_fix(s, "Number of objects adjusted.");
	}
801
	if (page->inuse != page->objects - nr) {
802
		slab_err(s, page, "Wrong object count. Counter is %d but "
803
804
			"counted were %d", page->inuse, page->objects - nr);
		page->inuse = page->objects - nr;
805
		slab_fix(s, "Object count adjusted.");
Christoph Lameter's avatar
Christoph Lameter committed
806
807
808
809
	}
	return search == NULL;
}

810
811
static void trace(struct kmem_cache *s, struct page *page, void *object,
								int alloc)
Christoph Lameter's avatar
Christoph Lameter committed
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
{
	if (s->flags & SLAB_TRACE) {
		printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
			s->name,
			alloc ? "alloc" : "free",
			object, page->inuse,
			page->freelist);

		if (!alloc)
			print_section("Object", (void *)object, s->objsize);

		dump_stack();
	}
}

827
828
829
830
831
832
/*
 * Hooks for other subsystems that check memory allocations. In a typical
 * production configuration these hooks all should produce no code at all.
 */
static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
{
833
	flags &= gfp_allowed_mask;
834
835
836
837
838
839
840
841
	lockdep_trace_alloc(flags);
	might_sleep_if(flags & __GFP_WAIT);

	return should_failslab(s->objsize, flags, s->flags);
}

static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
{
842
	flags &= gfp_allowed_mask;
843
	kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
844
845
846
847
848
849
850
	kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
}

static inline void slab_free_hook(struct kmem_cache *s, void *x)
{
	kmemleak_free_recursive(x, s->flags);

851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
	/*
	 * Trouble is that we may no longer disable interupts in the fast path
	 * So in order to make the debug calls that expect irqs to be
	 * disabled we need to disable interrupts temporarily.
	 */
#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
	{
		unsigned long flags;

		local_irq_save(flags);
		kmemcheck_slab_free(s, x, s->objsize);
		debug_check_no_locks_freed(x, s->objsize);
		local_irq_restore(flags);
	}
#endif
866
867
	if (!(s->flags & SLAB_DEBUG_OBJECTS))
		debug_check_no_obj_freed(x, s->objsize);
868
869
}

870
/*
Christoph Lameter's avatar
Christoph Lameter committed
871
 * Tracking of fully allocated slabs for debugging purposes.
872
 */
Christoph Lameter's avatar
Christoph Lameter committed
873
static void add_full(struct kmem_cache_node *n, struct page *page)
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
{
	spin_lock(&n->list_lock);
	list_add(&page->lru, &n->full);
	spin_unlock(&n->list_lock);
}

static void remove_full(struct kmem_cache *s, struct page *page)
{
	struct kmem_cache_node *n;

	if (!(s->flags & SLAB_STORE_USER))
		return;

	n = get_node(s, page_to_nid(page));

	spin_lock(&n->list_lock);
	list_del(&page->lru);
	spin_unlock(&n->list_lock);
}

894
895
896
897
898
899
900
901
/* Tracking of the number of slabs for debugging purposes */
static inline unsigned long slabs_node(struct kmem_cache *s, int node)
{
	struct kmem_cache_node *n = get_node(s, node);

	return atomic_long_read(&n->nr_slabs);
}

902
903
904
905
906
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
{
	return atomic_long_read(&n->nr_slabs);
}

907
static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
908
909
910
911
912
913
914
915
916
{
	struct kmem_cache_node *n = get_node(s, node);

	/*
	 * May be called early in order to allocate a slab for the
	 * kmem_cache_node structure. Solve the chicken-egg
	 * dilemma by deferring the increment of the count during
	 * bootstrap (see early_kmem_cache_node_alloc).
	 */
917
	if (n) {
918
		atomic_long_inc(&n->nr_slabs);
919
920
		atomic_long_add(objects, &n->total_objects);
	}
921
}
922
static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
923
924
925
926
{
	struct kmem_cache_node *n = get_node(s, node);

	atomic_long_dec(&n->nr_slabs);
927
	atomic_long_sub(objects, &n->total_objects);
928
929
930
}

/* Object debug checks for alloc/free paths */
Christoph Lameter's avatar
Christoph Lameter committed
931
932
933
934
935
936
static void setup_object_debug(struct kmem_cache *s, struct page *page,
								void *object)
{
	if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
		return;

937
	init_object(s, object, SLUB_RED_INACTIVE);
Christoph Lameter's avatar
Christoph Lameter committed
938
939
940
	init_tracking(s, object);
}

941
static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
942
					void *object, unsigned long addr)
Christoph Lameter's avatar
Christoph Lameter committed
943
944
945
946
{
	if (!check_slab(s, page))
		goto bad;

947
	if (!on_freelist(s, page, object)) {
948
		object_err(s, page, object, "Object already allocated");
949
		goto bad;
Christoph Lameter's avatar
Christoph Lameter committed
950
951
952
953
	}

	if (!check_valid_pointer(s, page, object)) {
		object_err(s, page, object, "Freelist Pointer check fails");
954
		goto bad;
Christoph Lameter's avatar
Christoph Lameter committed
955
956
	}

957
	if (!check_object(s, page, object, SLUB_RED_INACTIVE))
Christoph Lameter's avatar
Christoph Lameter committed
958
959
		goto bad;

Christoph Lameter's avatar
Christoph Lameter committed
960
961
962
963
	/* Success perform special debug activities for allocs */
	if (s->flags & SLAB_STORE_USER)
		set_track(s, object, TRACK_ALLOC, addr);
	trace(s, page, object, 1);
964
	init_object(s, object, SLUB_RED_ACTIVE);
Christoph Lameter's avatar
Christoph Lameter committed
965
	return 1;
Christoph Lameter's avatar
Christoph Lameter committed
966

Christoph Lameter's avatar
Christoph Lameter committed
967
968
969
970
971
bad:
	if (PageSlab(page)) {
		/*
		 * If this is a slab page then lets do the best we can
		 * to avoid issues in the future. Marking all objects
Christoph Lameter's avatar
Christoph Lameter committed
972
		 * as used avoids touching the remaining objects.
Christoph Lameter's avatar
Christoph Lameter committed
973
		 */
974
		slab_fix(s, "Marking all objects used");
975
		page->inuse = page->objects;
976
		page->freelist = NULL;
Christoph Lameter's avatar
Christoph Lameter committed
977
978
979
980
	}
	return 0;
}

981
982
static noinline int free_debug_processing(struct kmem_cache *s,
		 struct page *page, void *object, unsigned long addr)
Christoph Lameter's avatar
Christoph Lameter committed
983
984
985
986
987
{
	if (!check_slab(s, page))
		goto fail;

	if (!check_valid_pointer(s, page, object)) {
988
		slab_err(s, page, "Invalid object pointer 0x%p", object);
Christoph Lameter's avatar
Christoph Lameter committed
989
990
991
992
		goto fail;
	}

	if (on_freelist(s, page, object)) {
993
		object_err(s, page, object, "Object already free");
Christoph Lameter's avatar
Christoph Lameter committed
994
995
996
		goto fail;
	}

997
	if (!check_object(s, page, object, SLUB_RED_ACTIVE))
Christoph Lameter's avatar
Christoph Lameter committed
998
999
1000
		return 0;

	if (unlikely(s != page->slab)) {
Ingo Molnar's avatar
Ingo Molnar committed
1001
		if (!PageSlab(page)) {
1002
1003
			slab_err(s, page, "Attempt to free object(0x%p) "
				"outside of slab", object);
Ingo Molnar's avatar
Ingo Molnar committed
1004
		} else if (!page->slab) {
Christoph Lameter's avatar
Christoph Lameter committed
1005
			printk(KERN_ERR
1006
				"SLUB <none>: no slab for object 0x%p.\n",
Christoph Lameter's avatar
Christoph Lameter committed
1007
						object);
1008
			dump_stack();
1009
		} else
1010
1011
			object_err(s, page, object,
					"page slab pointer corrupt.");
Christoph Lameter's avatar
Christoph Lameter committed
1012
1013
		goto fail;
	}
Christoph Lameter's avatar
Christoph Lameter committed
1014
1015

	/* Special debug activities for freeing objects */
1016
	if (!PageSlubFrozen(page) && !page->freelist)
Christoph Lameter's avatar
Christoph Lameter committed
1017
1018
1019
1020
		remove_full(s, page);
	if (s->flags & SLAB_STORE_USER)
		set_track(s, object, TRACK_FREE, addr);
	trace(s, page, object, 0);
1021
	init_object(s, object, SLUB_RED_INACTIVE);
Christoph Lameter's avatar
Christoph Lameter committed
1022
	return 1;
Christoph Lameter's avatar
Christoph Lameter committed
1023

Christoph Lameter's avatar
Christoph Lameter committed
1024
fail:
1025
	slab_fix(s, "Object at 0x%p not freed", object);
Christoph Lameter's avatar
Christoph Lameter committed
1026
1027
1028
	return 0;
}

1029
1030
static int __init setup_slub_debug(char *str)
{
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
	slub_debug = DEBUG_DEFAULT_FLAGS;
	if (*str++ != '=' || !*str)
		/*
		 * No options specified. Switch on full debugging.
		 */
		goto out;

	if (*str == ',')
		/*
		 * No options but restriction on slabs. This means full
		 * debugging for slabs matching a pattern.
		 */
		goto check_slabs;

1045
1046
1047
1048
1049
1050
1051
1052
1053
	if (tolower(*str) == 'o') {
		/*
		 * Avoid enabling debugging on caches if its minimum order
		 * would increase as a result.
		 */
		disable_higher_order_debug = 1;
		goto out;
	}

1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
	slub_debug = 0;
	if (*str == '-')
		/*
		 * Switch off all debugging measures.
		 */
		goto out;

	/*
	 * Determine which debug features should be switched on
	 */
1064
	for (; *str && *str != ','; str++) {
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
		switch (tolower(*str)) {
		case 'f':
			slub_debug |= SLAB_DEBUG_FREE;
			break;
		case 'z':
			slub_debug |= SLAB_RED_ZONE;
			break;
		case 'p':
			slub_debug |= SLAB_POISON;
			break;
		case 'u':
			slub_debug |= SLAB_STORE_USER;
			break;
		case 't':
			slub_debug |= SLAB_TRACE;
			break;
1081
1082
1083
		case 'a':
			slub_debug |= SLAB_FAILSLAB;
			break;
1084
1085
		default:
			printk(KERN_ERR "slub_debug option '%c' "
1086
				"unknown. skipped\n", *str);
1087
		}
1088
1089
	}

1090
check_slabs:
1091
1092
	if (*str == ',')
		slub_debug_slabs = str + 1;
1093
out:
1094
1095
1096
1097
1098
	return 1;
}

__setup("slub_debug", setup_slub_debug);

1099
1100
static unsigned long kmem_cache_flags(unsigned long objsize,
	unsigned long flags, const char *name,
1101
	void (*ctor)(void *))
1102
1103
{
	/*
1104
	 * Enable debugging if selected on the kernel commandline.
1105
	 */
1106
	if (slub_debug && (!slub_debug_slabs ||
1107
1108
		!strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
		flags |= slub_debug;
1109
1110

	return flags;
1111
1112
}
#else
Christoph Lameter's avatar
Christoph Lameter committed
1113
1114
static inline void setup_object_debug(struct kmem_cache *s,
			struct page *page, void *object) {}
1115

Christoph Lameter's avatar
Christoph Lameter committed
1116
static inline int alloc_debug_processing(struct kmem_cache *s,
1117
	struct page *page, void *object, unsigned long addr) { return 0; }
1118

Christoph Lameter's avatar
Christoph Lameter committed
1119
static inline int free_debug_processing(struct kmem_cache *s,
1120
	struct page *page, void *object, unsigned long addr) { return 0; }
1121
1122
1123
1124

static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
			{ return 1; }
static inline int check_object(struct kmem_cache *s, struct page *page,
1125
			void *object, u8 val) { return 1; }
Christoph Lameter's avatar
Christoph Lameter committed
1126
static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
1127
1128
static inline unsigned long kmem_cache_flags(unsigned long objsize,
	unsigned long flags, const char *name,
1129
	void (*ctor)(void *))
1130
1131
1132
{
	return flags;
}
1133
#define slub_debug 0
1134

1135
1136
#define disable_higher_order_debug 0

1137
1138
static inline unsigned long slabs_node(struct kmem_cache *s, int node)
							{ return 0; }
1139
1140
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
							{ return 0; }
1141
1142
1143
1144
static inline void inc_slabs_node(struct kmem_cache *s, int node,
							int objects) {}
static inline void dec_slabs_node(struct kmem_cache *s, int node,
							int objects) {}
1145
1146
1147
1148
1149
1150
1151
1152
1153

static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
							{ return 0; }

static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
		void *object) {}

static inline void slab_free_hook(struct kmem_cache *s, void *x) {}

1154
#endif /* CONFIG_SLUB_DEBUG */
1155

Christoph Lameter's avatar
Christoph Lameter committed
1156
1157
1158
/*
 * Slab allocation and freeing
 */
1159
1160
1161
1162
1163
static inline struct page *alloc_slab_page(gfp_t flags, int node,
					struct kmem_cache_order_objects oo)
{
	int order = oo_order(oo);

1164
1165
	flags |= __GFP_NOTRACK;

1166
	if (node == NUMA_NO_NODE)
1167
1168
		return alloc_pages(flags, order);
	else
1169
		return alloc_pages_exact_node(node, flags, order);
1170
1171
}

Christoph Lameter's avatar
Christoph Lameter committed
1172
1173
static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
{
1174
	struct page *page;
1175
	struct kmem_cache_order_objects oo = s->oo;
1176
	gfp_t alloc_gfp;
Christoph Lameter's avatar
Christoph Lameter committed
1177

1178
	flags |= s->allocflags;
1179

1180
1181
1182
1183
1184
1185
1186
	/*
	 * Let the initial higher-order allocation fail under memory pressure
	 * so we fall-back to the minimum order allocation.
	 */
	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;

	page = alloc_slab_page(alloc_gfp, node, oo);
1187
1188
1189
1190
1191
1192
1193
1194
1195
	if (unlikely(!page)) {
		oo = s->min;
		/*
		 * Allocation may have failed due to fragmentation.
		 * Try a lower order alloc if possible
		 */
		page = alloc_slab_page(flags, node, oo);
		if (!page)
			return NULL;
Christoph Lameter's avatar
Christoph Lameter committed
1196

1197
		stat(s, ORDER_FALLBACK);
1198
	}
Vegard Nossum's avatar
Vegard Nossum committed
1199
1200

	if (kmemcheck_enabled
1201
		&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
		int pages = 1 << oo_order(oo);

		kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);

		/*
		 * Objects from caches that have a constructor don't get
		 * cleared when they're allocated, so we need to do it here.
		 */
		if (s->ctor)
			kmemcheck_mark_uninitialized_pages(page, pages);
		else
			kmemcheck_mark_unallocated_pages(page, pages);
Vegard Nossum's avatar
Vegard Nossum committed
1214
1215
	}

1216
	page->objects = oo_objects(oo);
Christoph Lameter's avatar
Christoph Lameter committed
1217
1218
1219
	mod_zone_page_state(page_zone(page),
		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1220
		1 << oo_order(oo));
Christoph Lameter's avatar
Christoph Lameter committed
1221
1222
1223
1224
1225
1226
1227

	return page;
}

static void setup_object(struct kmem_cache *s, struct page *page,
				void *object)
{
Christoph Lameter's avatar
Christoph Lameter committed
1228
	setup_object_debug(s, page, object);
1229
	if (unlikely(s->ctor))
1230
		s->ctor(object);
Christoph Lameter's avatar
Christoph Lameter committed
1231
1232
1233
1234
1235
1236
1237
1238
1239
}

static struct page