slub.c 110 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
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

/*
 * 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
76
77
 * 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
78
 * freed then the slab will show up again on the partial lists.
Christoph Lameter's avatar
Christoph Lameter committed
79
80
 * We track full slabs for debugging purposes though because otherwise we
 * cannot scan all objects.
Christoph Lameter's avatar
Christoph Lameter committed
81
82
83
84
85
86
87
 *
 * 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.
 *
88
89
90
91
92
93
94
95
96
97
98
99
 * 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
100
 * 			freelist that allows lockless access to
101
102
 * 			free objects in addition to the regular freelist
 * 			that requires the slab lock.
Christoph Lameter's avatar
Christoph Lameter committed
103
104
105
 *
 * PageError		Slab requires special handling due to debug
 * 			options set. This moves	slab handling out of
106
 * 			the fast path and disables lockless freelists.
Christoph Lameter's avatar
Christoph Lameter committed
107
108
 */

109
110
111
112
113
#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)
{
114
#ifdef CONFIG_SLUB_DEBUG
115
	return unlikely(s->flags & SLAB_DEBUG_FLAGS);
116
#else
117
	return 0;
118
#endif
119
}
120

Christoph Lameter's avatar
Christoph Lameter committed
121
122
123
124
125
126
127
128
129
130
131
/*
 * 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

132
133
134
135
/*
 * Mininum number of partial slabs. These will be left on the partial
 * lists even if they are empty. kmem_cache_shrink may reclaim them.
 */
136
#define MIN_PARTIAL 5
Christoph Lameter's avatar
Christoph Lameter committed
137

138
139
140
141
142
143
144
/*
 * 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
145
146
#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
				SLAB_POISON | SLAB_STORE_USER)
Christoph Lameter's avatar
Christoph Lameter committed
147

148
/*
149
150
151
 * 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.
152
 */
153
#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
154

Christoph Lameter's avatar
Christoph Lameter committed
155
156
157
158
/*
 * Set of flags that will prevent slab merging
 */
#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
159
160
		SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
		SLAB_FAILSLAB)
Christoph Lameter's avatar
Christoph Lameter committed
161
162

#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
Vegard Nossum's avatar
Vegard Nossum committed
163
		SLAB_CACHE_DMA | SLAB_NOTRACK)
Christoph Lameter's avatar
Christoph Lameter committed
164

165
166
167
168
#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
169
/* Internal SLUB flags */
Christoph Lameter's avatar
Christoph Lameter committed
170
#define __OBJECT_POISON		0x80000000UL /* Poison object */
Christoph Lameter's avatar
Christoph Lameter committed
171
172
173
174
175
176
177
178
179

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 */
180
	PARTIAL,	/* Kmem_cache_node works */
Christoph Lameter's avatar
Christoph Lameter committed
181
	UP,		/* Everything works but does not show up in sysfs */
Christoph Lameter's avatar
Christoph Lameter committed
182
183
184
185
186
	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
187
static LIST_HEAD(slab_caches);
Christoph Lameter's avatar
Christoph Lameter committed
188

189
190
191
192
/*
 * Tracking user of a slab.
 */
struct track {
193
	unsigned long addr;	/* Called from address */
194
195
196
197
198
199
200
	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 };

201
#ifdef CONFIG_SLUB_DEBUG
Christoph Lameter's avatar
Christoph Lameter committed
202
203
204
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 *);
205

Christoph Lameter's avatar
Christoph Lameter committed
206
#else
207
208
209
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; }
210
211
static inline void sysfs_slab_remove(struct kmem_cache *s)
{
212
	kfree(s->name);
213
214
	kfree(s);
}
215

Christoph Lameter's avatar
Christoph Lameter committed
216
217
#endif

218
static inline void stat(struct kmem_cache *s, enum stat_item si)
219
220
{
#ifdef CONFIG_SLUB_STATS
221
	__this_cpu_inc(s->cpu_slab->stat[si]);
222
223
224
#endif
}

Christoph Lameter's avatar
Christoph Lameter committed
225
226
227
228
229
230
231
232
233
234
235
236
237
238
/********************************************************************
 * 			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
239
/* Verify that a pointer has an address that is valid within a slab page */
240
241
242
243
244
static inline int check_valid_pointer(struct kmem_cache *s,
				struct page *page, const void *object)
{
	void *base;

245
	if (!object)
246
247
		return 1;

248
	base = page_address(page);
249
	if (object < base || object >= base + page->objects * s->size ||
250
251
252
253
254
255
256
		(object - base) % s->size) {
		return 0;
	}

	return 1;
}

257
258
259
260
261
262
263
264
265
266
267
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 */
268
269
#define for_each_object(__p, __s, __addr, __objects) \
	for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
270
271
272
273
			__p += (__s)->size)

/* Scan freelist */
#define for_each_free_object(__p, __s, __free) \
274
	for (__p = (__free); __p; __p = get_freepointer((__s), __p))
275
276
277
278
279
280
281

/* 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;
}

282
283
284
285
static inline struct kmem_cache_order_objects oo_make(int order,
						unsigned long size)
{
	struct kmem_cache_order_objects x = {
286
		(order << OO_SHIFT) + (PAGE_SIZE << order) / size
287
288
289
290
291
292
293
	};

	return x;
}

static inline int oo_order(struct kmem_cache_order_objects x)
{
294
	return x.x >> OO_SHIFT;
295
296
297
298
}

static inline int oo_objects(struct kmem_cache_order_objects x)
{
299
	return x.x & OO_MASK;
300
301
}

302
303
304
305
#ifdef CONFIG_SLUB_DEBUG
/*
 * Debug settings:
 */
306
307
308
#ifdef CONFIG_SLUB_DEBUG_ON
static int slub_debug = DEBUG_DEFAULT_FLAGS;
#else
309
static int slub_debug;
310
#endif
311
312

static char *slub_debug_slabs;
313
static int disable_higher_order_debug;
314

Christoph Lameter's avatar
Christoph Lameter committed
315
316
317
318
319
320
321
322
323
324
325
326
327
/*
 * 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) {
328
			printk(KERN_ERR "%8s 0x%p: ", text, addr + i);
Christoph Lameter's avatar
Christoph Lameter committed
329
330
			newline = 0;
		}
331
		printk(KERN_CONT " %02x", addr[i]);
Christoph Lameter's avatar
Christoph Lameter committed
332
333
334
		offset = i % 16;
		ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
		if (offset == 15) {
335
			printk(KERN_CONT " %s\n", ascii);
Christoph Lameter's avatar
Christoph Lameter committed
336
337
338
339
340
341
			newline = 1;
		}
	}
	if (!newline) {
		i %= 16;
		while (i < 16) {
342
			printk(KERN_CONT "   ");
Christoph Lameter's avatar
Christoph Lameter committed
343
344
345
			ascii[i] = ' ';
			i++;
		}
346
		printk(KERN_CONT " %s\n", ascii);
Christoph Lameter's avatar
Christoph Lameter committed
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
	}
}

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,
364
			enum track_item alloc, unsigned long addr)
Christoph Lameter's avatar
Christoph Lameter committed
365
{
Akinobu Mita's avatar
Akinobu Mita committed
366
	struct track *p = get_track(s, object, alloc);
Christoph Lameter's avatar
Christoph Lameter committed
367
368
369
370

	if (addr) {
		p->addr = addr;
		p->cpu = smp_processor_id();
371
		p->pid = current->pid;
Christoph Lameter's avatar
Christoph Lameter committed
372
373
374
375
376
377
378
		p->when = jiffies;
	} else
		memset(p, 0, sizeof(struct track));
}

static void init_tracking(struct kmem_cache *s, void *object)
{
379
380
381
	if (!(s->flags & SLAB_STORE_USER))
		return;

382
383
	set_track(s, object, TRACK_FREE, 0UL);
	set_track(s, object, TRACK_ALLOC, 0UL);
Christoph Lameter's avatar
Christoph Lameter committed
384
385
386
387
388
389
390
}

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

391
	printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
392
		s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
393
394
395
396
397
398
399
400
401
402
403
404
405
}

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)
{
406
407
	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);
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423

}

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
424
425
}

426
427
428
429
430
431
432
433
434
435
436
437
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
438
439
{
	unsigned int off;	/* Offset of last byte */
440
	u8 *addr = page_address(page);
441
442
443
444
445
446
447
448
449
450
451

	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);

452
	print_section("Object", p, min_t(unsigned long, s->objsize, PAGE_SIZE));
Christoph Lameter's avatar
Christoph Lameter committed
453
454
455
456
457
458
459
460
461
462

	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;

463
	if (s->flags & SLAB_STORE_USER)
Christoph Lameter's avatar
Christoph Lameter committed
464
465
466
467
		off += 2 * sizeof(struct track);

	if (off != s->size)
		/* Beginning of the filler is the free pointer */
468
469
470
		print_section("Padding", p + off, s->size - off);

	dump_stack();
Christoph Lameter's avatar
Christoph Lameter committed
471
472
473
474
475
}

static void object_err(struct kmem_cache *s, struct page *page,
			u8 *object, char *reason)
{
476
	slab_bug(s, "%s", reason);
477
	print_trailer(s, page, object);
Christoph Lameter's avatar
Christoph Lameter committed
478
479
}

480
static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
Christoph Lameter's avatar
Christoph Lameter committed
481
482
483
484
{
	va_list args;
	char buf[100];

485
486
	va_start(args, fmt);
	vsnprintf(buf, sizeof(buf), fmt, args);
Christoph Lameter's avatar
Christoph Lameter committed
487
	va_end(args);
488
	slab_bug(s, "%s", buf);
489
	print_page_info(page);
Christoph Lameter's avatar
Christoph Lameter committed
490
491
492
493
494
495
496
497
498
	dump_stack();
}

static void init_object(struct kmem_cache *s, void *object, int active)
{
	u8 *p = object;

	if (s->flags & __OBJECT_POISON) {
		memset(p, POISON_FREE, s->objsize - 1);
499
		p[s->objsize - 1] = POISON_END;
Christoph Lameter's avatar
Christoph Lameter committed
500
501
502
503
504
505
506
507
	}

	if (s->flags & SLAB_RED_ZONE)
		memset(p + s->objsize,
			active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE,
			s->inuse - s->objsize);
}

508
static u8 *check_bytes(u8 *start, unsigned int value, unsigned int bytes)
Christoph Lameter's avatar
Christoph Lameter committed
509
510
511
{
	while (bytes) {
		if (*start != (u8)value)
512
			return start;
Christoph Lameter's avatar
Christoph Lameter committed
513
514
515
		start++;
		bytes--;
	}
516
517
518
519
520
521
522
523
524
525
526
527
	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,
528
			u8 *start, unsigned int value, unsigned int bytes)
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
{
	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
548
549
550
551
552
553
554
555
556
}

/*
 * 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
557
 *
Christoph Lameter's avatar
Christoph Lameter committed
558
559
560
561
562
 * 	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
563
564
565
 * 	Padding is extended by another word if Redzoning is enabled and
 * 	objsize == inuse.
 *
Christoph Lameter's avatar
Christoph Lameter committed
566
567
568
569
 * 	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
570
571
 * 	Meta data starts here.
 *
Christoph Lameter's avatar
Christoph Lameter committed
572
573
 * 	A. Free pointer (if we cannot overwrite object on free)
 * 	B. Tracking data for SLAB_STORE_USER
Christoph Lameter's avatar
Christoph Lameter committed
574
 * 	C. Padding to reach required alignment boundary or at mininum
Christoph Lameter's avatar
Christoph Lameter committed
575
 * 		one word if debugging is on to be able to detect writes
Christoph Lameter's avatar
Christoph Lameter committed
576
577
578
 * 		before the word boundary.
 *
 *	Padding is done using 0x5a (POISON_INUSE)
Christoph Lameter's avatar
Christoph Lameter committed
579
580
 *
 * object + s->size
Christoph Lameter's avatar
Christoph Lameter committed
581
 * 	Nothing is used beyond s->size.
Christoph Lameter's avatar
Christoph Lameter committed
582
 *
Christoph Lameter's avatar
Christoph Lameter committed
583
584
 * 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
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
 * 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;

603
604
	return check_bytes_and_report(s, page, p, "Object padding",
				p + off, POISON_INUSE, s->size - off);
Christoph Lameter's avatar
Christoph Lameter committed
605
606
}

607
/* Check the pad bytes at the end of a slab page */
Christoph Lameter's avatar
Christoph Lameter committed
608
609
static int slab_pad_check(struct kmem_cache *s, struct page *page)
{
610
611
612
613
614
	u8 *start;
	u8 *fault;
	u8 *end;
	int length;
	int remainder;
Christoph Lameter's avatar
Christoph Lameter committed
615
616
617
618

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

619
	start = page_address(page);
620
	length = (PAGE_SIZE << compound_order(page));
621
622
	end = start + length;
	remainder = length % s->size;
Christoph Lameter's avatar
Christoph Lameter committed
623
624
625
	if (!remainder)
		return 1;

626
	fault = check_bytes(end - remainder, POISON_INUSE, remainder);
627
628
629
630
631
632
	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);
633
	print_section("Padding", end - remainder, remainder);
634

Eric Dumazet's avatar
Eric Dumazet committed
635
	restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
636
	return 0;
Christoph Lameter's avatar
Christoph Lameter committed
637
638
639
640
641
642
643
644
645
646
647
648
}

static int check_object(struct kmem_cache *s, struct page *page,
					void *object, int active)
{
	u8 *p = object;
	u8 *endobject = object + s->objsize;

	if (s->flags & SLAB_RED_ZONE) {
		unsigned int red =
			active ? SLUB_RED_ACTIVE : SLUB_RED_INACTIVE;

649
650
		if (!check_bytes_and_report(s, page, object, "Redzone",
			endobject, red, s->inuse - s->objsize))
Christoph Lameter's avatar
Christoph Lameter committed
651
652
			return 0;
	} else {
Ingo Molnar's avatar
Ingo Molnar committed
653
654
655
656
		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
657
658
659
660
	}

	if (s->flags & SLAB_POISON) {
		if (!active && (s->flags & __OBJECT_POISON) &&
661
662
663
			(!check_bytes_and_report(s, page, p, "Poison", p,
					POISON_FREE, s->objsize - 1) ||
			 !check_bytes_and_report(s, page, p, "Poison",
664
				p + s->objsize - 1, POISON_END, 1)))
Christoph Lameter's avatar
Christoph Lameter committed
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
			return 0;
		/*
		 * check_pad_bytes cleans up on its own.
		 */
		check_pad_bytes(s, page, p);
	}

	if (!s->offset && active)
		/*
		 * 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
683
		 * No choice but to zap it and thus lose the remainder
Christoph Lameter's avatar
Christoph Lameter committed
684
		 * of the free objects in this slab. May cause
Christoph Lameter's avatar
Christoph Lameter committed
685
		 * another error because the object count is now wrong.
Christoph Lameter's avatar
Christoph Lameter committed
686
		 */
687
		set_freepointer(s, p, NULL);
Christoph Lameter's avatar
Christoph Lameter committed
688
689
690
691
692
693
694
		return 0;
	}
	return 1;
}

static int check_slab(struct kmem_cache *s, struct page *page)
{
695
696
	int maxobj;

Christoph Lameter's avatar
Christoph Lameter committed
697
698
699
	VM_BUG_ON(!irqs_disabled());

	if (!PageSlab(page)) {
700
		slab_err(s, page, "Not a valid slab page");
Christoph Lameter's avatar
Christoph Lameter committed
701
702
		return 0;
	}
703
704
705
706
707
708
709
710

	maxobj = (PAGE_SIZE << compound_order(page)) / s->size;
	if (page->objects > maxobj) {
		slab_err(s, page, "objects %u > max %u",
			s->name, page->objects, maxobj);
		return 0;
	}
	if (page->inuse > page->objects) {
711
		slab_err(s, page, "inuse %u > max %u",
712
			s->name, page->inuse, page->objects);
Christoph Lameter's avatar
Christoph Lameter committed
713
714
715
716
717
718
719
720
		return 0;
	}
	/* Slab_pad_check fixes things up after itself */
	slab_pad_check(s, page);
	return 1;
}

/*
Christoph Lameter's avatar
Christoph Lameter committed
721
722
 * 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
723
724
725
726
727
728
 */
static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
{
	int nr = 0;
	void *fp = page->freelist;
	void *object = NULL;
729
	unsigned long max_objects;
Christoph Lameter's avatar
Christoph Lameter committed
730

731
	while (fp && nr <= page->objects) {
Christoph Lameter's avatar
Christoph Lameter committed
732
733
734
735
736
737
		if (fp == search)
			return 1;
		if (!check_valid_pointer(s, page, fp)) {
			if (object) {
				object_err(s, page, object,
					"Freechain corrupt");
738
				set_freepointer(s, object, NULL);
Christoph Lameter's avatar
Christoph Lameter committed
739
740
				break;
			} else {
741
				slab_err(s, page, "Freepointer corrupt");
742
				page->freelist = NULL;
743
				page->inuse = page->objects;
744
				slab_fix(s, "Freelist cleared");
Christoph Lameter's avatar
Christoph Lameter committed
745
746
747
748
749
750
751
752
753
				return 0;
			}
			break;
		}
		object = fp;
		fp = get_freepointer(s, object);
		nr++;
	}

754
	max_objects = (PAGE_SIZE << compound_order(page)) / s->size;
755
756
	if (max_objects > MAX_OBJS_PER_PAGE)
		max_objects = MAX_OBJS_PER_PAGE;
757
758
759
760
761
762
763

	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.");
	}
764
	if (page->inuse != page->objects - nr) {
765
		slab_err(s, page, "Wrong object count. Counter is %d but "
766
767
			"counted were %d", page->inuse, page->objects - nr);
		page->inuse = page->objects - nr;
768
		slab_fix(s, "Object count adjusted.");
Christoph Lameter's avatar
Christoph Lameter committed
769
770
771
772
	}
	return search == NULL;
}

773
774
static void trace(struct kmem_cache *s, struct page *page, void *object,
								int alloc)
Christoph Lameter's avatar
Christoph Lameter committed
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
{
	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();
	}
}

790
791
792
793
794
795
/*
 * 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)
{
796
	flags &= gfp_allowed_mask;
797
798
799
800
801
802
803
804
	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)
{
805
	flags &= gfp_allowed_mask;
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
	kmemcheck_slab_alloc(s, flags, object, s->objsize);
	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);
}

static inline void slab_free_hook_irq(struct kmem_cache *s, void *object)
{
	kmemcheck_slab_free(s, object, s->objsize);
	debug_check_no_locks_freed(object, s->objsize);
	if (!(s->flags & SLAB_DEBUG_OBJECTS))
		debug_check_no_obj_freed(object, s->objsize);
}

823
/*
Christoph Lameter's avatar
Christoph Lameter committed
824
 * Tracking of fully allocated slabs for debugging purposes.
825
 */
Christoph Lameter's avatar
Christoph Lameter committed
826
static void add_full(struct kmem_cache_node *n, struct page *page)
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
{
	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);
}

847
848
849
850
851
852
853
854
/* 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);
}

855
856
857
858
859
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
{
	return atomic_long_read(&n->nr_slabs);
}

860
static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
861
862
863
864
865
866
867
868
869
{
	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).
	 */
870
	if (n) {
871
		atomic_long_inc(&n->nr_slabs);
872
873
		atomic_long_add(objects, &n->total_objects);
	}
874
}
875
static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
876
877
878
879
{
	struct kmem_cache_node *n = get_node(s, node);

	atomic_long_dec(&n->nr_slabs);
880
	atomic_long_sub(objects, &n->total_objects);
881
882
883
}

/* Object debug checks for alloc/free paths */
Christoph Lameter's avatar
Christoph Lameter committed
884
885
886
887
888
889
890
891
892
893
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;

	init_object(s, object, 0);
	init_tracking(s, object);
}

894
static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
895
					void *object, unsigned long addr)
Christoph Lameter's avatar
Christoph Lameter committed
896
897
898
899
{
	if (!check_slab(s, page))
		goto bad;

900
	if (!on_freelist(s, page, object)) {
901
		object_err(s, page, object, "Object already allocated");
902
		goto bad;
Christoph Lameter's avatar
Christoph Lameter committed
903
904
905
906
	}

	if (!check_valid_pointer(s, page, object)) {
		object_err(s, page, object, "Freelist Pointer check fails");
907
		goto bad;
Christoph Lameter's avatar
Christoph Lameter committed
908
909
	}

910
	if (!check_object(s, page, object, 0))
Christoph Lameter's avatar
Christoph Lameter committed
911
912
		goto bad;

Christoph Lameter's avatar
Christoph Lameter committed
913
914
915
916
917
	/* 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);
	init_object(s, object, 1);
Christoph Lameter's avatar
Christoph Lameter committed
918
	return 1;
Christoph Lameter's avatar
Christoph Lameter committed
919

Christoph Lameter's avatar
Christoph Lameter committed
920
921
922
923
924
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
925
		 * as used avoids touching the remaining objects.
Christoph Lameter's avatar
Christoph Lameter committed
926
		 */
927
		slab_fix(s, "Marking all objects used");
928
		page->inuse = page->objects;
929
		page->freelist = NULL;
Christoph Lameter's avatar
Christoph Lameter committed
930
931
932
933
	}
	return 0;
}

934
935
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
936
937
938
939
940
{
	if (!check_slab(s, page))
		goto fail;

	if (!check_valid_pointer(s, page, object)) {
941
		slab_err(s, page, "Invalid object pointer 0x%p", object);
Christoph Lameter's avatar
Christoph Lameter committed
942
943
944
945
		goto fail;
	}

	if (on_freelist(s, page, object)) {
946
		object_err(s, page, object, "Object already free");
Christoph Lameter's avatar
Christoph Lameter committed
947
948
949
950
951
952
953
		goto fail;
	}

	if (!check_object(s, page, object, 1))
		return 0;

	if (unlikely(s != page->slab)) {
Ingo Molnar's avatar
Ingo Molnar committed
954
		if (!PageSlab(page)) {
955
956
			slab_err(s, page, "Attempt to free object(0x%p) "
				"outside of slab", object);
Ingo Molnar's avatar
Ingo Molnar committed
957
		} else if (!page->slab) {
Christoph Lameter's avatar
Christoph Lameter committed
958
			printk(KERN_ERR
959
				"SLUB <none>: no slab for object 0x%p.\n",
Christoph Lameter's avatar
Christoph Lameter committed
960
						object);
961
			dump_stack();
962
		} else
963
964
			object_err(s, page, object,
					"page slab pointer corrupt.");
Christoph Lameter's avatar
Christoph Lameter committed
965
966
		goto fail;
	}
Christoph Lameter's avatar
Christoph Lameter committed
967
968

	/* Special debug activities for freeing objects */
969
	if (!PageSlubFrozen(page) && !page->freelist)
Christoph Lameter's avatar
Christoph Lameter committed
970
971
972
973
974
		remove_full(s, page);
	if (s->flags & SLAB_STORE_USER)
		set_track(s, object, TRACK_FREE, addr);
	trace(s, page, object, 0);
	init_object(s, object, 0);
Christoph Lameter's avatar
Christoph Lameter committed
975
	return 1;
Christoph Lameter's avatar
Christoph Lameter committed
976

Christoph Lameter's avatar
Christoph Lameter committed
977
fail:
978
	slab_fix(s, "Object at 0x%p not freed", object);
Christoph Lameter's avatar
Christoph Lameter committed
979
980
981
	return 0;
}

982
983
static int __init setup_slub_debug(char *str)
{
984
985
986
987
988
989
990
991
992
993
994
995
996
997
	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;

998
999
1000
1001
1002
1003
1004
1005
1006
	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;
	}

1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
	slub_debug = 0;
	if (*str == '-')
		/*
		 * Switch off all debugging measures.
		 */
		goto out;

	/*
	 * Determine which debug features should be switched on
	 */
1017
	for (; *str && *str != ','; str++) {
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
		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;
1034
1035
1036
		case 'a':
			slub_debug |= SLAB_FAILSLAB;
			break;
1037
1038
		default:
			printk(KERN_ERR "slub_debug option '%c' "
1039
				"unknown. skipped\n", *str);
1040
		}
1041
1042
	}

1043
check_slabs:
1044
1045
	if (*str == ',')
		slub_debug_slabs = str + 1;
1046
out:
1047
1048
1049
1050
1051
	return 1;
}

__setup("slub_debug", setup_slub_debug);

1052
1053
static unsigned long kmem_cache_flags(unsigned long objsize,
	unsigned long flags, const char *name,
1054
	void (*ctor)(void *))
1055
1056
{
	/*
1057
	 * Enable debugging if selected on the kernel commandline.
1058
	 */
1059
	if (slub_debug && (!slub_debug_slabs ||
1060
1061
		!strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
		flags |= slub_debug;
1062
1063

	return flags;
1064
1065
}
#else
Christoph Lameter's avatar
Christoph Lameter committed
1066
1067
static inline void setup_object_debug(struct kmem_cache *s,
			struct page *page, void *object) {}
1068

Christoph Lameter's avatar
Christoph Lameter committed
1069
static inline int alloc_debug_processing(struct kmem_cache *s,
1070
	struct page *page, void *object, unsigned long addr) { return 0; }
1071

Christoph Lameter's avatar
Christoph Lameter committed
1072
static inline int free_debug_processing(struct kmem_cache *s,
1073
	struct page *page, void *object, unsigned long addr) { return 0; }
1074
1075
1076
1077
1078

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,
			void *object, int active) { return 1; }
Christoph Lameter's avatar
Christoph Lameter committed
1079
static inline void add_full(struct kmem_cache_node *n, struct page *page) {}
1080
1081
static inline unsigned long kmem_cache_flags(unsigned long objsize,
	unsigned long flags, const char *name,
1082
	void (*ctor)(void *))
1083
1084
1085
{
	return flags;
}
1086
#define slub_debug 0
1087

1088
1089
#define disable_higher_order_debug 0

1090
1091
static inline unsigned long slabs_node(struct kmem_cache *s, int node)
							{ return 0; }
1092
1093
static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
							{ return 0; }
1094
1095
1096
1097
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) {}
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109

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) {}

static inline void slab_free_hook_irq(struct kmem_cache *s,
		void *object) {}

1110
#endif
1111

Christoph Lameter's avatar
Christoph Lameter committed
1112
1113
1114
/*
 * Slab allocation and freeing
 */
1115
1116
1117
1118
1119
static inline struct page *alloc_slab_page(gfp_t flags, int node,
					struct kmem_cache_order_objects oo)
{
	int order = oo_order(oo);

1120
1121
	flags |= __GFP_NOTRACK;

1122
	if (node == NUMA_NO_NODE)
1123
1124
		return alloc_pages(flags, order);
	else
1125
		return alloc_pages_exact_node(node, flags, order);
1126
1127
}

Christoph Lameter's avatar
Christoph Lameter committed
1128
1129
static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
{
1130
	struct page *page;
1131
	struct kmem_cache_order_objects oo = s->oo;
1132
	gfp_t alloc_gfp;
Christoph Lameter's avatar
Christoph Lameter committed
1133

1134
	flags |= s->allocflags;
1135

1136
1137
1138
1139
1140
1141
1142
	/*
	 * 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);
1143
1144
1145
1146
1147
1148
1149
1150
1151
	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
1152

1153
		stat(s, ORDER_FALLBACK);
1154
	}
Vegard Nossum's avatar
Vegard Nossum committed
1155
1156

	if (kmemcheck_enabled
1157
		&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
		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
1170
1171
	}

1172
	page->objects = oo_objects(oo);
Christoph Lameter's avatar
Christoph Lameter committed
1173
1174
1175
	mod_zone_page_state(page_zone(page),
		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1176
		1 << oo_order(oo));
Christoph Lameter's avatar
Christoph Lameter committed
1177
1178
1179
1180
1181
1182
1183

	return page;
}

static void setup_object(struct kmem_cache *s, struct page *page,
				void *object)
{
Christoph Lameter's avatar
Christoph Lameter committed
1184
	setup_object_debug(s, page, object);
1185
	if (unlikely(s->ctor))
1186
		s->ctor(object);
Christoph Lameter's avatar
Christoph Lameter committed
1187
1188
1189
1190
1191
1192
1193
1194
1195
}

static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
{
	struct page *page;
	void *start;
	void *last;
	void *p;

Christoph Lameter's avatar
Christoph Lameter committed
1196
	BUG_ON(flags & GFP_SLAB_BUG_MASK);
Christoph Lameter's avatar
Christoph Lameter committed
1197

Christoph Lameter's avatar
Christoph Lameter committed
1198
1199
	page = allocate_slab(s,
		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
Christoph Lameter's avatar
Christoph Lameter committed
1200
1201
1202
	if (!page)
		goto out;

1203
	inc_slabs_node(s, page_to_nid(page), page->objects);
Christoph Lameter's avatar
Christoph Lameter committed
1204
1205
1206
1207
1208
1209
	page->slab = s;
	page->flags |= 1 << PG_slab;

	start = page_address(page);

	if (unlikely(s->flags & SLAB_POISON))
1210
		memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
Christoph Lameter's avatar
Christoph Lameter committed
1211
1212

	last = start;
1213
	for_each_object(p, s, start, page->objects) {
Christoph Lameter's avatar
Christoph Lameter committed
1214
1215
1216
1217
1218
		setup_object(s, page, last);
		set_freepointer(s, last, p);
		last = p;
	}
	setup_object(s, page, last);
1219
	set_freepointer(s, last, NULL);
Christoph Lameter's avatar
Christoph Lameter committed
1220
1221
1222
1223
1224
1225
1226
1227
1228

	page->freelist = start;
	page->inuse = 0;
out:
	return page;
}

static void __free_slab(struct kmem_cache *s, struct page *page)
{
1229
1230
	int order = compound_order(page);
	int pages = 1 << order;
Christoph Lameter's avatar
Christoph Lameter committed
1231

1232
	if (kmem_cache_debug(s)) {
Christoph Lameter's avatar
Christoph Lameter committed
1233
1234
1235
		void *p;

		slab_pad_check(s, page);
1236
1237
		for_each_object(p, s, page_address(page),
						page->objects)
Christoph Lameter's avatar
Christoph Lameter committed
1238
1239
1240
			check_object(s, page, p, 0);
	}

1241
	kmemcheck_free_shadow(page, compound_order(page));
Vegard Nossum's avatar
Vegard Nossum committed
1242

Christoph Lameter's avatar
Christoph Lameter committed
1243
1244
1245
	mod_zone_page_state(page_zone(page),
		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1246
		-pages);
Christoph Lameter's avatar
Christoph Lameter committed
1247

1248
1249
	__ClearPageSlab(page);
	reset_page_mapcount(page);
Nick Piggin's avatar
Nick Piggin committed
1250
1251
	if (current->reclaim_state)
		current->reclaim_state->reclaimed_slab += pages;
1252
	__free_pages(page, order);