slab.c 101 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
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
/*
 * linux/mm/slab.c
 * Written by Mark Hemment, 1996/97.
 * (markhe@nextd.demon.co.uk)
 *
 * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
 *
 * Major cleanup, different bufctl logic, per-cpu arrays
 *	(c) 2000 Manfred Spraul
 *
 * Cleanup, make the head arrays unconditional, preparation for NUMA
 * 	(c) 2002 Manfred Spraul
 *
 * An implementation of the Slab Allocator as described in outline in;
 *	UNIX Internals: The New Frontiers by Uresh Vahalia
 *	Pub: Prentice Hall	ISBN 0-13-101908-2
 * or with a little more detail in;
 *	The Slab Allocator: An Object-Caching Kernel Memory Allocator
 *	Jeff Bonwick (Sun Microsystems).
 *	Presented at: USENIX Summer 1994 Technical Conference
 *
 * The memory is organized in caches, one cache for each object type.
 * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
 * Each cache consists out of many slabs (they are small (usually one
 * page long) and always contiguous), and each slab contains multiple
 * initialized objects.
 *
 * This means, that your constructor is used only for newly allocated
 * slabs and you must pass objects with the same intializations to
 * kmem_cache_free.
 *
 * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM,
 * normal). If you need a special memory type, then must create a new
 * cache for that memory type.
 *
 * In order to reduce fragmentation, the slabs are sorted in 3 groups:
 *   full slabs with 0 free objects
 *   partial slabs
 *   empty slabs with no allocated objects
 *
 * If partial slabs exist, then new allocations come from these slabs,
 * otherwise from empty slabs or new slabs are allocated.
 *
 * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache
 * during kmem_cache_destroy(). The caller must prevent concurrent allocs.
 *
 * Each cache has a short per-cpu head array, most allocs
 * and frees go into that array, and if that array overflows, then 1/2
 * of the entries in the array are given back into the global cache.
 * The head array is strictly LIFO and should improve the cache hit rates.
 * On SMP, it additionally reduces the spinlock operations.
 *
 * The c_cpuarray may not be read with enabled local interrupts - 
 * it's changed with a smp_call_function().
 *
 * SMP synchronization:
 *  constructors and destructors are called without any locking.
58
 *  Several members in struct kmem_cache and struct slab never change, they
Linus Torvalds's avatar
Linus Torvalds committed
59
60
61
62
63
64
65
66
67
68
69
70
 *	are accessed without any locking.
 *  The per-cpu arrays are never accessed from the wrong cpu, no locking,
 *  	and local interrupts are disabled so slab code is preempt-safe.
 *  The non-constant members are protected with a per-cache irq spinlock.
 *
 * Many thanks to Mark Hemment, who wrote another per-cpu slab patch
 * in 2000 - many ideas in the current implementation are derived from
 * his patch.
 *
 * Further notes from the original documentation:
 *
 * 11 April '97.  Started multi-threading - markhe
Ingo Molnar's avatar
Ingo Molnar committed
71
 *	The global cache-chain is protected by the mutex 'cache_chain_mutex'.
Linus Torvalds's avatar
Linus Torvalds committed
72
73
74
75
76
77
 *	The sem is only needed when accessing/extending the cache-chain, which
 *	can never happen inside an interrupt (kmem_cache_create(),
 *	kmem_cache_shrink() and kmem_cache_reap()).
 *
 *	At present, each engine can be growing a cache.  This should be blocked.
 *
78
79
80
81
82
83
84
85
86
 * 15 March 2005. NUMA slab allocator.
 *	Shai Fultheim <shai@scalex86.org>.
 *	Shobhit Dayal <shobhit@calsoftinc.com>
 *	Alok N Kataria <alokk@calsoftinc.com>
 *	Christoph Lameter <christoph@lameter.com>
 *
 *	Modified the slab allocator to be node aware on NUMA systems.
 *	Each node has its own list of partial, free and full slabs.
 *	All object allocations for a node occur from node specific slab lists.
Linus Torvalds's avatar
Linus Torvalds committed
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
 */

#include	<linux/config.h>
#include	<linux/slab.h>
#include	<linux/mm.h>
#include	<linux/swap.h>
#include	<linux/cache.h>
#include	<linux/interrupt.h>
#include	<linux/init.h>
#include	<linux/compiler.h>
#include	<linux/seq_file.h>
#include	<linux/notifier.h>
#include	<linux/kallsyms.h>
#include	<linux/cpu.h>
#include	<linux/sysctl.h>
#include	<linux/module.h>
#include	<linux/rcupdate.h>
104
#include	<linux/string.h>
105
#include	<linux/nodemask.h>
106
#include	<linux/mempolicy.h>
Ingo Molnar's avatar
Ingo Molnar committed
107
#include	<linux/mutex.h>
Linus Torvalds's avatar
Linus Torvalds committed
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202

#include	<asm/uaccess.h>
#include	<asm/cacheflush.h>
#include	<asm/tlbflush.h>
#include	<asm/page.h>

/*
 * DEBUG	- 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
 *		  SLAB_RED_ZONE & SLAB_POISON.
 *		  0 for faster, smaller code (especially in the critical paths).
 *
 * STATS	- 1 to collect stats for /proc/slabinfo.
 *		  0 for faster, smaller code (especially in the critical paths).
 *
 * FORCED_DEBUG	- 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
 */

#ifdef CONFIG_DEBUG_SLAB
#define	DEBUG		1
#define	STATS		1
#define	FORCED_DEBUG	1
#else
#define	DEBUG		0
#define	STATS		0
#define	FORCED_DEBUG	0
#endif

/* Shouldn't this be in a header file somewhere? */
#define	BYTES_PER_WORD		sizeof(void *)

#ifndef cache_line_size
#define cache_line_size()	L1_CACHE_BYTES
#endif

#ifndef ARCH_KMALLOC_MINALIGN
/*
 * Enforce a minimum alignment for the kmalloc caches.
 * Usually, the kmalloc caches are cache_line_size() aligned, except when
 * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
 * alignment larger than BYTES_PER_WORD. ARCH_KMALLOC_MINALIGN allows that.
 * Note that this flag disables some debug features.
 */
#define ARCH_KMALLOC_MINALIGN 0
#endif

#ifndef ARCH_SLAB_MINALIGN
/*
 * Enforce a minimum alignment for all caches.
 * Intended for archs that get misalignment faults even for BYTES_PER_WORD
 * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
 * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
 * some debug features.
 */
#define ARCH_SLAB_MINALIGN 0
#endif

#ifndef ARCH_KMALLOC_FLAGS
#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
#endif

/* Legal flag mask for kmem_cache_create(). */
#if DEBUG
# define CREATE_MASK	(SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
			 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
			 SLAB_NO_REAP | SLAB_CACHE_DMA | \
			 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \
			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
			 SLAB_DESTROY_BY_RCU)
#else
# define CREATE_MASK	(SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \
			 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \
			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
			 SLAB_DESTROY_BY_RCU)
#endif

/*
 * kmem_bufctl_t:
 *
 * Bufctl's are used for linking objs within a slab
 * linked offsets.
 *
 * This implementation relies on "struct page" for locating the cache &
 * slab an object belongs to.
 * This allows the bufctl structure to be small (one int), but limits
 * the number of objects a slab (not a cache) can contain when off-slab
 * bufctls are used. The limit is the size of the largest general cache
 * that does not use off-slab slabs.
 * For 32bit archs with 4 kB pages, is this 56.
 * This is not serious, as it is only for large objects, when it is unwise
 * to have too many per slab.
 * Note: This limit can be raised by introducing a general cache whose size
 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
 */

203
typedef unsigned int kmem_bufctl_t;
Linus Torvalds's avatar
Linus Torvalds committed
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
#define BUFCTL_END	(((kmem_bufctl_t)(~0U))-0)
#define BUFCTL_FREE	(((kmem_bufctl_t)(~0U))-1)
#define	SLAB_LIMIT	(((kmem_bufctl_t)(~0U))-2)

/* Max number of objs-per-slab for caches which use off-slab slabs.
 * Needed to avoid a possible looping condition in cache_grow().
 */
static unsigned long offslab_limit;

/*
 * struct slab
 *
 * Manages the objs in a slab. Placed either at the beginning of mem allocated
 * for a slab, or allocated from an general cache.
 * Slabs are chained into three list: fully used, partial, fully free slabs.
 */
struct slab {
221
222
223
224
225
226
	struct list_head list;
	unsigned long colouroff;
	void *s_mem;		/* including colour offset */
	unsigned int inuse;	/* num of objs active in slab */
	kmem_bufctl_t free;
	unsigned short nodeid;
Linus Torvalds's avatar
Linus Torvalds committed
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
};

/*
 * struct slab_rcu
 *
 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
 * arrange for kmem_freepages to be called via RCU.  This is useful if
 * we need to approach a kernel structure obliquely, from its address
 * obtained without the usual locking.  We can lock the structure to
 * stabilize it and check it's still at the given address, only if we
 * can be sure that the memory has not been meanwhile reused for some
 * other kind of object (which our subsystem's lock might corrupt).
 *
 * rcu_read_lock before reading the address, then rcu_read_unlock after
 * taking the spinlock within the structure expected at that address.
 *
 * We assume struct slab_rcu can overlay struct slab when destroying.
 */
struct slab_rcu {
246
	struct rcu_head head;
247
	struct kmem_cache *cachep;
248
	void *addr;
Linus Torvalds's avatar
Linus Torvalds committed
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
};

/*
 * struct array_cache
 *
 * Purpose:
 * - LIFO ordering, to hand out cache-warm objects from _alloc
 * - reduce the number of linked list operations
 * - reduce spinlock operations
 *
 * The limit is stored in the per-cpu structure to reduce the data cache
 * footprint.
 *
 */
struct array_cache {
	unsigned int avail;
	unsigned int limit;
	unsigned int batchcount;
	unsigned int touched;
268
269
270
271
272
273
274
	spinlock_t lock;
	void *entry[0];		/*
				 * Must have this definition in here for the proper
				 * alignment of array_cache. Also simplifies accessing
				 * the entries.
				 * [0] is for gcc 2.95. It should really be [].
				 */
Linus Torvalds's avatar
Linus Torvalds committed
275
276
277
278
279
280
281
282
};

/* bootstrap: The caches do not work without cpuarrays anymore,
 * but the cpuarrays are allocated from the generic caches...
 */
#define BOOT_CPUCACHE_ENTRIES	1
struct arraycache_init {
	struct array_cache cache;
283
	void *entries[BOOT_CPUCACHE_ENTRIES];
Linus Torvalds's avatar
Linus Torvalds committed
284
285
286
};

/*
287
 * The slab lists for all objects.
Linus Torvalds's avatar
Linus Torvalds committed
288
289
 */
struct kmem_list3 {
290
291
292
293
294
295
296
	struct list_head slabs_partial;	/* partial list first, better asm code */
	struct list_head slabs_full;
	struct list_head slabs_free;
	unsigned long free_objects;
	unsigned long next_reap;
	int free_touched;
	unsigned int free_limit;
297
	unsigned int colour_next;	/* Per-node cache coloring */
298
299
300
	spinlock_t list_lock;
	struct array_cache *shared;	/* shared per node */
	struct array_cache **alien;	/* on other nodes */
Linus Torvalds's avatar
Linus Torvalds committed
301
302
};

303
304
305
306
307
308
309
310
311
312
/*
 * Need this for bootstrapping a per node allocator.
 */
#define NUM_INIT_LISTS (2 * MAX_NUMNODES + 1)
struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
#define	CACHE_CACHE 0
#define	SIZE_AC 1
#define	SIZE_L3 (1 + MAX_NUMNODES)

/*
313
 * This function must be completely optimized away if
314
315
316
317
 * a constant is passed to it. Mostly the same as
 * what is in linux/slab.h except it returns an
 * index.
 */
318
static __always_inline int index_of(const size_t size)
319
{
320
321
	extern void __bad_size(void);

322
323
324
325
326
327
328
329
330
331
	if (__builtin_constant_p(size)) {
		int i = 0;

#define CACHE(x) \
	if (size <=x) \
		return i; \
	else \
		i++;
#include "linux/kmalloc_sizes.h"
#undef CACHE
332
		__bad_size();
333
	} else
334
		__bad_size();
335
336
337
338
339
	return 0;
}

#define INDEX_AC index_of(sizeof(struct arraycache_init))
#define INDEX_L3 index_of(sizeof(struct kmem_list3))
Linus Torvalds's avatar
Linus Torvalds committed
340

Pekka Enberg's avatar
Pekka Enberg committed
341
static void kmem_list3_init(struct kmem_list3 *parent)
342
343
344
345
346
347
{
	INIT_LIST_HEAD(&parent->slabs_full);
	INIT_LIST_HEAD(&parent->slabs_partial);
	INIT_LIST_HEAD(&parent->slabs_free);
	parent->shared = NULL;
	parent->alien = NULL;
348
	parent->colour_next = 0;
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
	spin_lock_init(&parent->list_lock);
	parent->free_objects = 0;
	parent->free_touched = 0;
}

#define MAKE_LIST(cachep, listp, slab, nodeid)	\
	do {	\
		INIT_LIST_HEAD(listp);		\
		list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
	} while (0)

#define	MAKE_ALL_LISTS(cachep, ptr, nodeid)			\
	do {					\
	MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid);	\
	MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
	MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid);	\
	} while (0)
Linus Torvalds's avatar
Linus Torvalds committed
366
367

/*
368
 * struct kmem_cache
Linus Torvalds's avatar
Linus Torvalds committed
369
370
371
 *
 * manages a cache.
 */
372

373
struct kmem_cache {
Linus Torvalds's avatar
Linus Torvalds committed
374
/* 1) per-cpu data, touched during every alloc/free */
375
376
377
378
	struct array_cache *array[NR_CPUS];
	unsigned int batchcount;
	unsigned int limit;
	unsigned int shared;
379
	unsigned int buffer_size;
380
/* 2) touched by every alloc & free from the backend */
381
382
383
384
	struct kmem_list3 *nodelists[MAX_NUMNODES];
	unsigned int flags;	/* constant flags */
	unsigned int num;	/* # of objs per slab */
	spinlock_t spinlock;
Linus Torvalds's avatar
Linus Torvalds committed
385
386
387

/* 3) cache_grow/shrink */
	/* order of pgs per slab (2^n) */
388
	unsigned int gfporder;
Linus Torvalds's avatar
Linus Torvalds committed
389
390

	/* force GFP flags, e.g. GFP_DMA */
391
	gfp_t gfpflags;
Linus Torvalds's avatar
Linus Torvalds committed
392

393
394
	size_t colour;		/* cache colouring range */
	unsigned int colour_off;	/* colour offset */
395
	struct kmem_cache *slabp_cache;
396
397
	unsigned int slab_size;
	unsigned int dflags;	/* dynamic flags */
Linus Torvalds's avatar
Linus Torvalds committed
398
399

	/* constructor func */
400
	void (*ctor) (void *, struct kmem_cache *, unsigned long);
Linus Torvalds's avatar
Linus Torvalds committed
401
402

	/* de-constructor func */
403
	void (*dtor) (void *, struct kmem_cache *, unsigned long);
Linus Torvalds's avatar
Linus Torvalds committed
404
405

/* 4) cache creation/removal */
406
407
	const char *name;
	struct list_head next;
Linus Torvalds's avatar
Linus Torvalds committed
408
409
410

/* 5) statistics */
#if STATS
411
412
413
414
415
416
417
418
419
420
421
422
423
	unsigned long num_active;
	unsigned long num_allocations;
	unsigned long high_mark;
	unsigned long grown;
	unsigned long reaped;
	unsigned long errors;
	unsigned long max_freeable;
	unsigned long node_allocs;
	unsigned long node_frees;
	atomic_t allochit;
	atomic_t allocmiss;
	atomic_t freehit;
	atomic_t freemiss;
Linus Torvalds's avatar
Linus Torvalds committed
424
425
#endif
#if DEBUG
426
427
428
429
430
431
432
433
	/*
	 * If debugging is enabled, then the allocator can add additional
	 * fields and/or padding to every object. buffer_size contains the total
	 * object size including these internal fields, the following two
	 * variables contain the offset to the user object and its size.
	 */
	int obj_offset;
	int obj_size;
Linus Torvalds's avatar
Linus Torvalds committed
434
435
436
437
438
439
440
441
442
443
#endif
};

#define CFLGS_OFF_SLAB		(0x80000000UL)
#define	OFF_SLAB(x)	((x)->flags & CFLGS_OFF_SLAB)

#define BATCHREFILL_LIMIT	16
/* Optimization question: fewer reaps means less 
 * probability for unnessary cpucache drain/refill cycles.
 *
Adrian Bunk's avatar
Adrian Bunk committed
444
 * OTOH the cpuarrays can contain lots of objects,
Linus Torvalds's avatar
Linus Torvalds committed
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
 * which could lock up otherwise freeable slabs.
 */
#define REAPTIMEOUT_CPUC	(2*HZ)
#define REAPTIMEOUT_LIST3	(4*HZ)

#if STATS
#define	STATS_INC_ACTIVE(x)	((x)->num_active++)
#define	STATS_DEC_ACTIVE(x)	((x)->num_active--)
#define	STATS_INC_ALLOCED(x)	((x)->num_allocations++)
#define	STATS_INC_GROWN(x)	((x)->grown++)
#define	STATS_INC_REAPED(x)	((x)->reaped++)
#define	STATS_SET_HIGH(x)	do { if ((x)->num_active > (x)->high_mark) \
					(x)->high_mark = (x)->num_active; \
				} while (0)
#define	STATS_INC_ERR(x)	((x)->errors++)
#define	STATS_INC_NODEALLOCS(x)	((x)->node_allocs++)
461
#define	STATS_INC_NODEFREES(x)	((x)->node_frees++)
Linus Torvalds's avatar
Linus Torvalds committed
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
#define	STATS_SET_FREEABLE(x, i) \
				do { if ((x)->max_freeable < i) \
					(x)->max_freeable = i; \
				} while (0)

#define STATS_INC_ALLOCHIT(x)	atomic_inc(&(x)->allochit)
#define STATS_INC_ALLOCMISS(x)	atomic_inc(&(x)->allocmiss)
#define STATS_INC_FREEHIT(x)	atomic_inc(&(x)->freehit)
#define STATS_INC_FREEMISS(x)	atomic_inc(&(x)->freemiss)
#else
#define	STATS_INC_ACTIVE(x)	do { } while (0)
#define	STATS_DEC_ACTIVE(x)	do { } while (0)
#define	STATS_INC_ALLOCED(x)	do { } while (0)
#define	STATS_INC_GROWN(x)	do { } while (0)
#define	STATS_INC_REAPED(x)	do { } while (0)
#define	STATS_SET_HIGH(x)	do { } while (0)
#define	STATS_INC_ERR(x)	do { } while (0)
#define	STATS_INC_NODEALLOCS(x)	do { } while (0)
480
#define	STATS_INC_NODEFREES(x)	do { } while (0)
Linus Torvalds's avatar
Linus Torvalds committed
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
#define	STATS_SET_FREEABLE(x, i) \
				do { } while (0)

#define STATS_INC_ALLOCHIT(x)	do { } while (0)
#define STATS_INC_ALLOCMISS(x)	do { } while (0)
#define STATS_INC_FREEHIT(x)	do { } while (0)
#define STATS_INC_FREEMISS(x)	do { } while (0)
#endif

#if DEBUG
/* Magic nums for obj red zoning.
 * Placed in the first word before and the first word after an obj.
 */
#define	RED_INACTIVE	0x5A2CF071UL	/* when obj is inactive */
#define	RED_ACTIVE	0x170FC2A5UL	/* when obj is active */

/* ...and for poisoning */
#define	POISON_INUSE	0x5a	/* for use-uninitialised poisoning */
#define POISON_FREE	0x6b	/* for use-after-free poisoning */
#define	POISON_END	0xa5	/* end-byte of poisoning */

/* memory layout of objects:
 * 0		: objp
504
 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
Linus Torvalds's avatar
Linus Torvalds committed
505
506
 * 		the end of an object is aligned with the end of the real
 * 		allocation. Catches writes behind the end of the allocation.
507
 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
Linus Torvalds's avatar
Linus Torvalds committed
508
 * 		redzone word.
509
510
511
 * cachep->obj_offset: The real object.
 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address [BYTES_PER_WORD long]
Linus Torvalds's avatar
Linus Torvalds committed
512
 */
513
static int obj_offset(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
514
{
515
	return cachep->obj_offset;
Linus Torvalds's avatar
Linus Torvalds committed
516
517
}

518
static int obj_size(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
519
{
520
	return cachep->obj_size;
Linus Torvalds's avatar
Linus Torvalds committed
521
522
}

523
static unsigned long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
524
525
{
	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
526
	return (unsigned long*) (objp+obj_offset(cachep)-BYTES_PER_WORD);
Linus Torvalds's avatar
Linus Torvalds committed
527
528
}

529
static unsigned long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
530
531
532
{
	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
	if (cachep->flags & SLAB_STORE_USER)
533
		return (unsigned long *)(objp + cachep->buffer_size -
534
					 2 * BYTES_PER_WORD);
535
	return (unsigned long *)(objp + cachep->buffer_size - BYTES_PER_WORD);
Linus Torvalds's avatar
Linus Torvalds committed
536
537
}

538
static void **dbg_userword(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
539
540
{
	BUG_ON(!(cachep->flags & SLAB_STORE_USER));
541
	return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
Linus Torvalds's avatar
Linus Torvalds committed
542
543
544
545
}

#else

546
547
#define obj_offset(x)			0
#define obj_size(cachep)		(cachep->buffer_size)
Linus Torvalds's avatar
Linus Torvalds committed
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
#define dbg_redzone1(cachep, objp)	({BUG(); (unsigned long *)NULL;})
#define dbg_redzone2(cachep, objp)	({BUG(); (unsigned long *)NULL;})
#define dbg_userword(cachep, objp)	({BUG(); (void **)NULL;})

#endif

/*
 * Maximum size of an obj (in 2^order pages)
 * and absolute limit for the gfp order.
 */
#if defined(CONFIG_LARGE_ALLOCS)
#define	MAX_OBJ_ORDER	13	/* up to 32Mb */
#define	MAX_GFP_ORDER	13	/* up to 32Mb */
#elif defined(CONFIG_MMU)
#define	MAX_OBJ_ORDER	5	/* 32 pages */
#define	MAX_GFP_ORDER	5	/* 32 pages */
#else
#define	MAX_OBJ_ORDER	8	/* up to 1Mb */
#define	MAX_GFP_ORDER	8	/* up to 1Mb */
#endif

/*
 * Do not go above this order unless 0 objects fit into the slab.
 */
#define	BREAK_GFP_ORDER_HI	1
#define	BREAK_GFP_ORDER_LO	0
static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;

576
/* Functions for storing/retrieving the cachep and or slab from the
Linus Torvalds's avatar
Linus Torvalds committed
577
578
579
 * global 'mem_map'. These are used to find the slab an obj belongs to.
 * With kfree(), these are used to find the cache which an obj belongs to.
 */
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
static inline void page_set_cache(struct page *page, struct kmem_cache *cache)
{
	page->lru.next = (struct list_head *)cache;
}

static inline struct kmem_cache *page_get_cache(struct page *page)
{
	return (struct kmem_cache *)page->lru.next;
}

static inline void page_set_slab(struct page *page, struct slab *slab)
{
	page->lru.prev = (struct list_head *)slab;
}

static inline struct slab *page_get_slab(struct page *page)
{
	return (struct slab *)page->lru.prev;
}
Linus Torvalds's avatar
Linus Torvalds committed
599

600
601
602
603
604
605
606
607
608
609
610
611
static inline struct kmem_cache *virt_to_cache(const void *obj)
{
	struct page *page = virt_to_page(obj);
	return page_get_cache(page);
}

static inline struct slab *virt_to_slab(const void *obj)
{
	struct page *page = virt_to_page(obj);
	return page_get_slab(page);
}

612
613
614
615
616
617
618
619
620
621
622
623
static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
				 unsigned int idx)
{
	return slab->s_mem + cache->buffer_size * idx;
}

static inline unsigned int obj_to_index(struct kmem_cache *cache,
					struct slab *slab, void *obj)
{
	return (unsigned)(obj - slab->s_mem) / cache->buffer_size;
}

Linus Torvalds's avatar
Linus Torvalds committed
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
/* These are the default caches for kmalloc. Custom caches can have other sizes. */
struct cache_sizes malloc_sizes[] = {
#define CACHE(x) { .cs_size = (x) },
#include <linux/kmalloc_sizes.h>
	CACHE(ULONG_MAX)
#undef CACHE
};
EXPORT_SYMBOL(malloc_sizes);

/* Must match cache_sizes above. Out of line to keep cache footprint low. */
struct cache_names {
	char *name;
	char *name_dma;
};

static struct cache_names __initdata cache_names[] = {
#define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
#include <linux/kmalloc_sizes.h>
642
	{NULL,}
Linus Torvalds's avatar
Linus Torvalds committed
643
644
645
646
#undef CACHE
};

static struct arraycache_init initarray_cache __initdata =
647
    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
Linus Torvalds's avatar
Linus Torvalds committed
648
static struct arraycache_init initarray_generic =
649
    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
Linus Torvalds's avatar
Linus Torvalds committed
650
651

/* internal cache of cache description objs */
652
static struct kmem_cache cache_cache = {
653
654
655
	.batchcount = 1,
	.limit = BOOT_CPUCACHE_ENTRIES,
	.shared = 1,
656
	.buffer_size = sizeof(struct kmem_cache),
657
658
659
	.flags = SLAB_NO_REAP,
	.spinlock = SPIN_LOCK_UNLOCKED,
	.name = "kmem_cache",
Linus Torvalds's avatar
Linus Torvalds committed
660
#if DEBUG
661
	.obj_size = sizeof(struct kmem_cache),
Linus Torvalds's avatar
Linus Torvalds committed
662
663
664
665
#endif
};

/* Guard access to the cache-chain. */
Ingo Molnar's avatar
Ingo Molnar committed
666
static DEFINE_MUTEX(cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
static struct list_head cache_chain;

/*
 * vm_enough_memory() looks at this to determine how many
 * slab-allocated pages are possibly freeable under pressure
 *
 * SLAB_RECLAIM_ACCOUNT turns this on per-slab
 */
atomic_t slab_reclaim_pages;

/*
 * chicken and egg problem: delay the per-cpu array allocation
 * until the general caches are up.
 */
static enum {
	NONE,
683
684
	PARTIAL_AC,
	PARTIAL_L3,
Linus Torvalds's avatar
Linus Torvalds committed
685
686
687
688
689
	FULL
} g_cpucache_up;

static DEFINE_PER_CPU(struct work_struct, reap_work);

690
691
static void free_block(struct kmem_cache *cachep, void **objpp, int len, int node);
static void enable_cpucache(struct kmem_cache *cachep);
692
static void cache_reap(void *unused);
693
static int __node_shrink(struct kmem_cache *cachep, int node);
Linus Torvalds's avatar
Linus Torvalds committed
694

695
static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
696
697
698
699
{
	return cachep->array[smp_processor_id()];
}

700
static inline struct kmem_cache *__find_general_cachep(size_t size, gfp_t gfpflags)
Linus Torvalds's avatar
Linus Torvalds committed
701
702
703
704
705
{
	struct cache_sizes *csizep = malloc_sizes;

#if DEBUG
	/* This happens if someone tries to call
706
707
708
	 * kmem_cache_create(), or __kmalloc(), before
	 * the generic caches are initialized.
	 */
709
	BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
Linus Torvalds's avatar
Linus Torvalds committed
710
711
712
713
714
#endif
	while (size > csizep->cs_size)
		csizep++;

	/*
715
	 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
Linus Torvalds's avatar
Linus Torvalds committed
716
717
718
719
720
721
722
723
	 * has cs_{dma,}cachep==NULL. Thus no special case
	 * for large kmalloc calls required.
	 */
	if (unlikely(gfpflags & GFP_DMA))
		return csizep->cs_dmacachep;
	return csizep->cs_cachep;
}

724
struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
725
726
727
728
729
{
	return __find_general_cachep(size, gfpflags);
}
EXPORT_SYMBOL(kmem_find_general_cachep);

730
static size_t slab_mgmt_size(size_t nr_objs, size_t align)
Linus Torvalds's avatar
Linus Torvalds committed
731
{
732
733
	return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
}
Linus Torvalds's avatar
Linus Torvalds committed
734

735
736
737
738
739
740
741
742
743
/* Calculate the number of objects and left-over bytes for a given
   buffer size. */
static void cache_estimate(unsigned long gfporder, size_t buffer_size,
			   size_t align, int flags, size_t *left_over,
			   unsigned int *num)
{
	int nr_objs;
	size_t mgmt_size;
	size_t slab_size = PAGE_SIZE << gfporder;
Linus Torvalds's avatar
Linus Torvalds committed
744

745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
	/*
	 * The slab management structure can be either off the slab or
	 * on it. For the latter case, the memory allocated for a
	 * slab is used for:
	 *
	 * - The struct slab
	 * - One kmem_bufctl_t for each object
	 * - Padding to respect alignment of @align
	 * - @buffer_size bytes for each object
	 *
	 * If the slab management structure is off the slab, then the
	 * alignment will already be calculated into the size. Because
	 * the slabs are all pages aligned, the objects will be at the
	 * correct alignment when allocated.
	 */
	if (flags & CFLGS_OFF_SLAB) {
		mgmt_size = 0;
		nr_objs = slab_size / buffer_size;

		if (nr_objs > SLAB_LIMIT)
			nr_objs = SLAB_LIMIT;
	} else {
		/*
		 * Ignore padding for the initial guess. The padding
		 * is at most @align-1 bytes, and @buffer_size is at
		 * least @align. In the worst case, this result will
		 * be one greater than the number of objects that fit
		 * into the memory allocation when taking the padding
		 * into account.
		 */
		nr_objs = (slab_size - sizeof(struct slab)) /
			  (buffer_size + sizeof(kmem_bufctl_t));

		/*
		 * This calculated number will be either the right
		 * amount, or one greater than what we want.
		 */
		if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
		       > slab_size)
			nr_objs--;

		if (nr_objs > SLAB_LIMIT)
			nr_objs = SLAB_LIMIT;

		mgmt_size = slab_mgmt_size(nr_objs, align);
	}
	*num = nr_objs;
	*left_over = slab_size - nr_objs*buffer_size - mgmt_size;
Linus Torvalds's avatar
Linus Torvalds committed
793
794
795
796
}

#define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg)

797
static void __slab_error(const char *function, struct kmem_cache *cachep, char *msg)
Linus Torvalds's avatar
Linus Torvalds committed
798
799
{
	printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
800
	       function, cachep->name, msg);
Linus Torvalds's avatar
Linus Torvalds committed
801
802
803
	dump_stack();
}

804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
#ifdef CONFIG_NUMA
/*
 * Special reaping functions for NUMA systems called from cache_reap().
 * These take care of doing round robin flushing of alien caches (containing
 * objects freed on different nodes from which they were allocated) and the
 * flushing of remote pcps by calling drain_node_pages.
 */
static DEFINE_PER_CPU(unsigned long, reap_node);

static void init_reap_node(int cpu)
{
	int node;

	node = next_node(cpu_to_node(cpu), node_online_map);
	if (node == MAX_NUMNODES)
		node = 0;

	__get_cpu_var(reap_node) = node;
}

static void next_reap_node(void)
{
	int node = __get_cpu_var(reap_node);

	/*
	 * Also drain per cpu pages on remote zones
	 */
	if (node != numa_node_id())
		drain_node_pages(node);

	node = next_node(node, node_online_map);
	if (unlikely(node >= MAX_NUMNODES))
		node = first_node(node_online_map);
	__get_cpu_var(reap_node) = node;
}

#else
#define init_reap_node(cpu) do { } while (0)
#define next_reap_node(void) do { } while (0)
#endif

Linus Torvalds's avatar
Linus Torvalds committed
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
/*
 * Initiate the reap timer running on the target CPU.  We run at around 1 to 2Hz
 * via the workqueue/eventd.
 * Add the CPU number into the expiration time to minimize the possibility of
 * the CPUs getting into lockstep and contending for the global cache chain
 * lock.
 */
static void __devinit start_cpu_timer(int cpu)
{
	struct work_struct *reap_work = &per_cpu(reap_work, cpu);

	/*
	 * When this gets called from do_initcalls via cpucache_init(),
	 * init_workqueues() has already run, so keventd will be setup
	 * at that time.
	 */
	if (keventd_up() && reap_work->func == NULL) {
862
		init_reap_node(cpu);
Linus Torvalds's avatar
Linus Torvalds committed
863
864
865
866
867
		INIT_WORK(reap_work, cache_reap, NULL);
		schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu);
	}
}

868
static struct array_cache *alloc_arraycache(int node, int entries,
869
					    int batchcount)
Linus Torvalds's avatar
Linus Torvalds committed
870
{
871
	int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
Linus Torvalds's avatar
Linus Torvalds committed
872
873
	struct array_cache *nc = NULL;

874
	nc = kmalloc_node(memsize, GFP_KERNEL, node);
Linus Torvalds's avatar
Linus Torvalds committed
875
876
877
878
879
	if (nc) {
		nc->avail = 0;
		nc->limit = entries;
		nc->batchcount = batchcount;
		nc->touched = 0;
880
		spin_lock_init(&nc->lock);
Linus Torvalds's avatar
Linus Torvalds committed
881
882
883
884
	}
	return nc;
}

885
#ifdef CONFIG_NUMA
886
static void *__cache_alloc_node(struct kmem_cache *, gfp_t, int);
887

Pekka Enberg's avatar
Pekka Enberg committed
888
static struct array_cache **alloc_alien_cache(int node, int limit)
889
890
{
	struct array_cache **ac_ptr;
891
	int memsize = sizeof(void *) * MAX_NUMNODES;
892
893
894
895
896
897
898
899
900
901
902
903
904
	int i;

	if (limit > 1)
		limit = 12;
	ac_ptr = kmalloc_node(memsize, GFP_KERNEL, node);
	if (ac_ptr) {
		for_each_node(i) {
			if (i == node || !node_online(i)) {
				ac_ptr[i] = NULL;
				continue;
			}
			ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d);
			if (!ac_ptr[i]) {
905
				for (i--; i <= 0; i--)
906
907
908
909
910
911
912
913
914
					kfree(ac_ptr[i]);
				kfree(ac_ptr);
				return NULL;
			}
		}
	}
	return ac_ptr;
}

Pekka Enberg's avatar
Pekka Enberg committed
915
static void free_alien_cache(struct array_cache **ac_ptr)
916
917
918
919
920
921
922
{
	int i;

	if (!ac_ptr)
		return;

	for_each_node(i)
923
	    kfree(ac_ptr[i]);
924
925
926
927

	kfree(ac_ptr);
}

928
static void __drain_alien_cache(struct kmem_cache *cachep,
Pekka Enberg's avatar
Pekka Enberg committed
929
				struct array_cache *ac, int node)
930
931
932
933
934
{
	struct kmem_list3 *rl3 = cachep->nodelists[node];

	if (ac->avail) {
		spin_lock(&rl3->list_lock);
935
		free_block(cachep, ac->entry, ac->avail, node);
936
937
938
939
940
		ac->avail = 0;
		spin_unlock(&rl3->list_lock);
	}
}

941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
/*
 * Called from cache_reap() to regularly drain alien caches round robin.
 */
static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
{
	int node = __get_cpu_var(reap_node);

	if (l3->alien) {
		struct array_cache *ac = l3->alien[node];
		if (ac && ac->avail) {
			spin_lock_irq(&ac->lock);
			__drain_alien_cache(cachep, ac, node);
			spin_unlock_irq(&ac->lock);
		}
	}
}

958
static void drain_alien_cache(struct kmem_cache *cachep, struct array_cache **alien)
959
{
960
	int i = 0;
961
962
963
964
	struct array_cache *ac;
	unsigned long flags;

	for_each_online_node(i) {
965
		ac = alien[i];
966
967
968
969
970
971
972
973
		if (ac) {
			spin_lock_irqsave(&ac->lock, flags);
			__drain_alien_cache(cachep, ac, i);
			spin_unlock_irqrestore(&ac->lock, flags);
		}
	}
}
#else
974

975
#define drain_alien_cache(cachep, alien) do { } while (0)
976
#define reap_alien(cachep, l3) do { } while (0)
977

978
979
980
981
982
static inline struct array_cache **alloc_alien_cache(int node, int limit)
{
	return (struct array_cache **) 0x01020304ul;
}

983
984
985
static inline void free_alien_cache(struct array_cache **ac_ptr)
{
}
986

987
988
#endif

Linus Torvalds's avatar
Linus Torvalds committed
989
static int __devinit cpuup_callback(struct notifier_block *nfb,
990
				    unsigned long action, void *hcpu)
Linus Torvalds's avatar
Linus Torvalds committed
991
992
{
	long cpu = (long)hcpu;
993
	struct kmem_cache *cachep;
994
995
996
	struct kmem_list3 *l3 = NULL;
	int node = cpu_to_node(cpu);
	int memsize = sizeof(struct kmem_list3);
Linus Torvalds's avatar
Linus Torvalds committed
997
998
999

	switch (action) {
	case CPU_UP_PREPARE:
Ingo Molnar's avatar
Ingo Molnar committed
1000
		mutex_lock(&cache_chain_mutex);
1001
1002
1003
1004
1005
1006
		/* we need to do this right in the beginning since
		 * alloc_arraycache's are going to use this list.
		 * kmalloc_node allows us to add the slab to the right
		 * kmem_list3 and not this cpu's kmem_list3
		 */

Linus Torvalds's avatar
Linus Torvalds committed
1007
		list_for_each_entry(cachep, &cache_chain, next) {
1008
1009
1010
1011
1012
1013
			/* setup the size64 kmemlist for cpu before we can
			 * begin anything. Make sure some other cpu on this
			 * node has not already allocated this
			 */
			if (!cachep->nodelists[node]) {
				if (!(l3 = kmalloc_node(memsize,
1014
							GFP_KERNEL, node)))
1015
1016
1017
					goto bad;
				kmem_list3_init(l3);
				l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
1018
				    ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1019

1020
1021
1022
1023
1024
				/*
				 * The l3s don't come and go as CPUs come and
				 * go.  cache_chain_mutex is sufficient
				 * protection here.
				 */
1025
1026
				cachep->nodelists[node] = l3;
			}
Linus Torvalds's avatar
Linus Torvalds committed
1027

1028
1029
			spin_lock_irq(&cachep->nodelists[node]->list_lock);
			cachep->nodelists[node]->free_limit =
1030
1031
			    (1 + nr_cpus_node(node)) *
			    cachep->batchcount + cachep->num;
1032
1033
1034
1035
			spin_unlock_irq(&cachep->nodelists[node]->list_lock);
		}

		/* Now we can go ahead with allocating the shared array's
1036
		   & array cache's */
1037
		list_for_each_entry(cachep, &cache_chain, next) {
1038
			struct array_cache *nc;
1039
1040
			struct array_cache *shared;
			struct array_cache **alien;
1041

1042
			nc = alloc_arraycache(node, cachep->limit,
1043
						cachep->batchcount);
Linus Torvalds's avatar
Linus Torvalds committed
1044
1045
			if (!nc)
				goto bad;
1046
1047
1048
1049
1050
			shared = alloc_arraycache(node,
					cachep->shared * cachep->batchcount,
					0xbaadf00d);
			if (!shared)
				goto bad;
1051

1052
1053
1054
			alien = alloc_alien_cache(node, cachep->limit);
			if (!alien)
				goto bad;
Linus Torvalds's avatar
Linus Torvalds committed
1055
1056
			cachep->array[cpu] = nc;

1057
1058
1059
			l3 = cachep->nodelists[node];
			BUG_ON(!l3);

1060
1061
1062
1063
1064
1065
1066
1067
			spin_lock_irq(&l3->list_lock);
			if (!l3->shared) {
				/*
				 * We are serialised from CPU_DEAD or
				 * CPU_UP_CANCELLED by the cpucontrol lock
				 */
				l3->shared = shared;
				shared = NULL;
1068
			}
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
#ifdef CONFIG_NUMA
			if (!l3->alien) {
				l3->alien = alien;
				alien = NULL;
			}
#endif
			spin_unlock_irq(&l3->list_lock);

			kfree(shared);
			free_alien_cache(alien);
Linus Torvalds's avatar
Linus Torvalds committed
1079
		}
Ingo Molnar's avatar
Ingo Molnar committed
1080
		mutex_unlock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1081
1082
1083
1084
1085
1086
		break;
	case CPU_ONLINE:
		start_cpu_timer(cpu);
		break;
#ifdef CONFIG_HOTPLUG_CPU
	case CPU_DEAD:
1087
1088
1089
1090
1091
1092
1093
1094
		/*
		 * Even if all the cpus of a node are down, we don't free the
		 * kmem_list3 of any cache. This to avoid a race between
		 * cpu_down, and a kmalloc allocation from another cpu for
		 * memory from the node of the cpu going down.  The list3
		 * structure is usually allocated from kmem_cache_create() and
		 * gets destroyed at kmem_cache_destroy().
		 */
Linus Torvalds's avatar
Linus Torvalds committed
1095
1096
		/* fall thru */
	case CPU_UP_CANCELED:
Ingo Molnar's avatar
Ingo Molnar committed
1097
		mutex_lock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1098
1099
1100

		list_for_each_entry(cachep, &cache_chain, next) {
			struct array_cache *nc;
1101
1102
			struct array_cache *shared;
			struct array_cache **alien;
1103
			cpumask_t mask;
Linus Torvalds's avatar
Linus Torvalds committed
1104

1105
			mask = node_to_cpumask(node);
Linus Torvalds's avatar
Linus Torvalds committed
1106
1107
1108
			/* cpu is dead; no one can alloc from it. */
			nc = cachep->array[cpu];
			cachep->array[cpu] = NULL;
1109
1110
1111
			l3 = cachep->nodelists[node];

			if (!l3)
1112
				goto free_array_cache;
1113

1114
			spin_lock_irq(&l3->list_lock);
1115
1116
1117
1118

			/* Free limit for this kmem_list3 */
			l3->free_limit -= cachep->batchcount;
			if (nc)
1119
				free_block(cachep, nc->entry, nc->avail, node);
1120
1121

			if (!cpus_empty(mask)) {
1122
				spin_unlock_irq(&l3->list_lock);
1123
				goto free_array_cache;
1124
			}
1125

1126
1127
			shared = l3->shared;
			if (shared) {
1128
				free_block(cachep, l3->shared->entry,
1129
					   l3->shared->avail, node);
1130
1131
1132
				l3->shared = NULL;
			}

1133
1134
1135
1136
1137
1138
1139
1140
1141
			alien = l3->alien;
			l3->alien = NULL;

			spin_unlock_irq(&l3->list_lock);

			kfree(shared);
			if (alien) {
				drain_alien_cache(cachep, alien);
				free_alien_cache(alien);
1142
			}
1143
free_array_cache:
Linus Torvalds's avatar
Linus Torvalds committed
1144
1145
			kfree(nc);
		}
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
		/*
		 * In the previous loop, all the objects were freed to
		 * the respective cache's slabs,  now we can go ahead and
		 * shrink each nodelist to its limit.
		 */
		list_for_each_entry(cachep, &cache_chain, next) {
			l3 = cachep->nodelists[node];
			if (!l3)
				continue;
			spin_lock_irq(&l3->list_lock);
			/* free slabs belonging to this node */
			__node_shrink(cachep, node);
			spin_unlock_irq(&l3->list_lock);
		}
Ingo Molnar's avatar
Ingo Molnar committed
1160
		mutex_unlock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1161
1162
1163
1164
		break;
#endif
	}
	return NOTIFY_OK;
1165
      bad:
Ingo Molnar's avatar
Ingo Molnar committed
1166
	mutex_unlock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1167
1168
1169
1170
1171
	return NOTIFY_BAD;
}

static struct notifier_block cpucache_notifier = { &cpuup_callback, NULL, 0 };

1172
1173
1174
/*
 * swap the static kmem_list3 with kmalloced memory
 */
1175
static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list, int nodeid)
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
{
	struct kmem_list3 *ptr;

	BUG_ON(cachep->nodelists[nodeid] != list);
	ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, nodeid);
	BUG_ON(!ptr);

	local_irq_disable();
	memcpy(ptr, list, sizeof(struct kmem_list3));
	MAKE_ALL_LISTS(cachep, ptr, nodeid);
	cachep->nodelists[nodeid] = ptr;
	local_irq_enable();
}

Linus Torvalds's avatar
Linus Torvalds committed
1190
1191
1192
1193
1194
1195
1196
1197
/* Initialisation.
 * Called after the gfp() functions have been enabled, and before smp_init().
 */
void __init kmem_cache_init(void)
{
	size_t left_over;
	struct cache_sizes *sizes;
	struct cache_names *names;
1198
	int i;
1199
	int order;
1200
1201
1202
1203
1204
1205

	for (i = 0; i < NUM_INIT_LISTS; i++) {
		kmem_list3_init(&initkmem_list3[i]);
		if (i < MAX_NUMNODES)
			cache_cache.nodelists[i] = NULL;
	}
Linus Torvalds's avatar
Linus Torvalds committed
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215

	/*
	 * Fragmentation resistance on low memory - only use bigger
	 * page orders on machines with more than 32MB of memory.
	 */
	if (num_physpages > (32 << 20) >> PAGE_SHIFT)
		slab_break_gfp_order = BREAK_GFP_ORDER_HI;

	/* Bootstrap is tricky, because several objects are allocated
	 * from caches that do not exist yet:
1216
	 * 1) initialize the cache_cache cache: it contains the struct kmem_cache
Linus Torvalds's avatar
Linus Torvalds committed
1217
1218
	 *    structures of all caches, except cache_cache itself: cache_cache
	 *    is statically allocated.
1219
1220
1221
	 *    Initially an __init data area is used for the head array and the
	 *    kmem_list3 structures, it's replaced with a kmalloc allocated
	 *    array at the end of the bootstrap.
Linus Torvalds's avatar
Linus Torvalds committed
1222
	 * 2) Create the first kmalloc cache.
1223
	 *    The struct kmem_cache for the new cache is allocated normally.
1224
1225
1226
	 *    An __init data area is used for the head array.
	 * 3) Create the remaining kmalloc caches, with minimally sized
	 *    head arrays.
Linus Torvalds's avatar
Linus Torvalds committed
1227
1228
	 * 4) Replace the __init data head arrays for cache_cache and the first
	 *    kmalloc cache with kmalloc allocated arrays.
1229
1230
1231
	 * 5) Replace the __init data for kmem_list3 for cache_cache and
	 *    the other cache's with kmalloc allocated memory.
	 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
Linus Torvalds's avatar
Linus Torvalds committed
1232
1233
1234
1235
1236
1237
1238
	 */

	/* 1) create the cache_cache */
	INIT_LIST_HEAD(&cache_chain);
	list_add(&cache_cache.next, &cache_chain);
	cache_cache.colour_off = cache_line_size();
	cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
1239
	cache_cache.nodelists[numa_node_id()] = &initkmem_list3[CACHE_CACHE];
Linus Torvalds's avatar
Linus Torvalds committed
1240

1241
	cache_cache.buffer_size = ALIGN(cache_cache.buffer_size, cache_line_size());
Linus Torvalds's avatar
Linus Torvalds committed
1242

1243
1244
1245
1246
1247
1248
	for (order = 0; order < MAX_ORDER; order++) {
		cache_estimate(order, cache_cache.buffer_size,
			cache_line_size(), 0, &left_over, &cache_cache.num);
		if (cache_cache.num)
			break;
	}
Linus Torvalds's avatar
Linus Torvalds committed
1249
1250
	if (!cache_cache.num)
		BUG();
1251
	cache_cache.gfporder = order;
1252
1253
1254
	cache_cache.colour = left_over / cache_cache.colour_off;
	cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) +
				      sizeof(struct slab), cache_line_size());
Linus Torvalds's avatar
Linus Torvalds committed
1255
1256
1257
1258
1259

	/* 2+3) create the kmalloc caches */
	sizes = malloc_sizes;
	names = cache_names;

1260
1261
1262
1263
1264
1265
	/* Initialize the caches that provide memory for the array cache
	 * and the kmem_list3 structures first.
	 * Without this, further allocations will bug
	 */

	sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name,
1266
1267
1268
1269
						      sizes[INDEX_AC].cs_size,
						      ARCH_KMALLOC_MINALIGN,
						      (ARCH_KMALLOC_FLAGS |
						       SLAB_PANIC), NULL, NULL);
1270
1271
1272

	if (INDEX_AC != INDEX_L3)
		sizes[INDEX_L3].cs_cachep =
1273
1274
1275
1276
1277
		    kmem_cache_create(names[INDEX_L3].name,
				      sizes[INDEX_L3].cs_size,
				      ARCH_KMALLOC_MINALIGN,
				      (ARCH_KMALLOC_FLAGS | SLAB_PANIC), NULL,
				      NULL);
1278

Linus Torvalds's avatar
Linus Torvalds committed
1279
	while (sizes->cs_size != ULONG_MAX) {
1280
1281
		/*
		 * For performance, all the general caches are L1 aligned.
Linus Torvalds's avatar
Linus Torvalds committed
1282
1283
1284
		 * This should be particularly beneficial on SMP boxes, as it
		 * eliminates "false sharing".
		 * Note for systems short on memory removing the alignment will
1285
1286
		 * allow tighter packing of the smaller caches.
		 */
1287
		if (!sizes->cs_cachep)
1288
			sizes->cs_cachep = kmem_cache_create(names->name,
1289
1290
1291
1292
1293
							     sizes->cs_size,
							     ARCH_KMALLOC_MINALIGN,
							     (ARCH_KMALLOC_FLAGS
							      | SLAB_PANIC),
							     NULL, NULL);
Linus Torvalds's avatar
Linus Torvalds committed
1294
1295
1296

		/* Inc off-slab bufctl limit until the ceiling is hit. */
		if (!(OFF_SLAB(sizes->cs_cachep))) {
1297
			offslab_limit = sizes->cs_size - sizeof(struct slab);
Linus Torvalds's avatar
Linus Torvalds committed
1298
1299
1300
1301
			offslab_limit /= sizeof(kmem_bufctl_t);
		}

		sizes->cs_dmacachep = kmem_cache_create(names->name_dma,
1302
1303
1304
1305
1306
1307
							sizes->cs_size,
							ARCH_KMALLOC_MINALIGN,
							(ARCH_KMALLOC_FLAGS |
							 SLAB_CACHE_DMA |
							 SLAB_PANIC), NULL,
							NULL);
Linus Torvalds's avatar
Linus Torvalds committed
1308
1309
1310
1311
1312
1313

		sizes++;
		names++;
	}
	/* 4) Replace the bootstrap head arrays */
	{
1314
		void *ptr;
1315

Linus Torvalds's avatar
Linus Torvalds committed
1316
		ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1317

Linus Torvalds's avatar
Linus Torvalds committed
1318
		local_irq_disable();
1319
1320
		BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
		memcpy(ptr, cpu_cache_get(&cache_cache),
1321
		       sizeof(struct arraycache_init));
Linus Torvalds's avatar
Linus Torvalds committed
1322
1323
		cache_cache.array[smp_processor_id()] = ptr;
		local_irq_enable();
1324

Linus Torvalds's avatar
Linus Torvalds committed
1325
		ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
1326

Linus Torvalds's avatar
Linus Torvalds committed
1327
		local_irq_disable();
1328
		BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
1329
		       != &initarray_generic.cache);
1330
		memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
1331
		       sizeof(struct arraycache_init));
1332
		malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
1333
		    ptr;
Linus Torvalds's avatar
Linus Torvalds committed
1334
1335
		local_irq_enable();
	}
1336
1337
1338
1339
1340
	/* 5) Replace the bootstrap kmem_list3's */
	{
		int node;
		/* Replace the static kmem_list3 structures for the boot cpu */
		init_list(&cache_cache, &initkmem_list3[CACHE_CACHE],
1341
			  numa_node_id());
1342
1343
1344

		for_each_online_node(node) {
			init_list(malloc_sizes[INDEX_AC].cs_cachep,
1345
				  &initkmem_list3[SIZE_AC + node], node);
1346
1347
1348

			if (INDEX_AC != INDEX_L3) {
				init_list(malloc_sizes[INDEX_L3].cs_cachep,
1349
1350
					  &initkmem_list3[SIZE_L3 + node],
					  node);
1351
1352
1353
			}
		}
	}
Linus Torvalds's avatar
Linus Torvalds committed
1354

1355
	/* 6) resize the head arrays to their final sizes */
Linus Torvalds's avatar
Linus Torvalds committed
1356
	{
1357
		struct kmem_cache *cachep;
Ingo Molnar's avatar
Ingo Molnar committed
1358
		mutex_lock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1359
		list_for_each_entry(cachep, &cache_chain, next)
1360
		    enable_cpucache(cachep);
Ingo Molnar's avatar
Ingo Molnar committed
1361
		mutex_unlock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1362
1363
1364
1365
1366
1367
	}

	/* Done! */
	g_cpucache_up = FULL;

	/* Register a cpu startup notifier callback
1368
	 * that initializes cpu_cache_get for all new cpus
Linus Torvalds's avatar
Linus Torvalds committed
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
	 */
	register_cpu_notifier(&cpucache_notifier);

	/* The reap timers are started later, with a module init call:
	 * That part of the kernel is not yet operational.
	 */
}

static int __init cpucache_init(void)
{
	int cpu;

	/* 
	 * Register the timers that return unneeded
	 * pages to gfp.
	 */
1385
	for_each_online_cpu(cpu)
1386
	    start_cpu_timer(cpu);
Linus Torvalds's avatar
Linus Torvalds committed
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399

	return 0;
}

__initcall(cpucache_init);

/*
 * Interface to system's page allocator. No need to hold the cache-lock.
 *
 * If we requested dmaable memory, we will get it. Even if we
 * did not request dmaable memory, we might get it, but that
 * would be relatively rare and ignorable.
 */
1400
static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid)
Linus Torvalds's avatar
Linus Torvalds committed
1401
1402
1403
1404
1405
1406
{
	struct page *page;
	void *addr;
	int i;

	flags |= cachep->gfpflags;
1407
	page = alloc_pages_node(nodeid, flags, cachep->gfporder);
Linus Torvalds's avatar
Linus Torvalds committed
1408
1409
1410
1411
1412
1413
1414
1415
1416
	if (!page)
		return NULL;
	addr = page_address(page);

	i = (1 << cachep->gfporder);
	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
		atomic_add(i, &slab_reclaim_pages);
	add_page_state(nr_slab, i);
	while (i--) {
Nick Piggin's avatar
Nick Piggin committed
1417
		__SetPageSlab(page);
Linus Torvalds's avatar
Linus Torvalds committed
1418
1419
1420
1421
1422
1423
1424
1425
		page++;
	}
	return addr;
}

/*
 * Interface to system's page release.
 */
1426
static void kmem_freepages(struct kmem_cache *cachep, void *addr)
Linus Torvalds's avatar
Linus Torvalds committed
1427
{
1428
	unsigned long i = (1 << cachep->gfporder);
Linus Torvalds's avatar
Linus Torvalds committed
1429
1430
1431
1432
	struct page *page = virt_to_page(addr);
	const unsigned long nr_freed = i;

	while (i--) {
Nick Piggin's avatar
Nick Piggin committed
1433
1434
		BUG_ON(!PageSlab(page));
		__ClearPageSlab(page);
Linus Torvalds's avatar
Linus Torvalds committed
1435
1436
1437
1438
1439
1440
		page++;
	}
	sub_page_state(nr_slab, nr_freed);
	if (current->reclaim_state)
		current->reclaim_state->reclaimed_slab += nr_freed;
	free_pages((unsigned long)addr, cachep->gfporder);
1441
1442
	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
		atomic_sub(1 << cachep->gfporder, &slab_reclaim_pages);
Linus Torvalds's avatar
Linus Torvalds committed
1443
1444
1445
1446
}

static void kmem_rcu_free(struct rcu_head *head)
{
1447
	struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
1448
	struct kmem_cache *cachep = slab_rcu->cachep;
Linus Torvalds's avatar
Linus Torvalds committed
1449
1450
1451
1452
1453
1454
1455
1456
1457

	kmem_freepages(cachep, slab_rcu->addr);
	if (OFF_SLAB(cachep))
		kmem_cache_free(cachep->slabp_cache, slab_rcu);
}

#if DEBUG

#ifdef CONFIG_DEBUG_PAGEALLOC
1458
static void store_stackinfo(struct kmem_cache *cache