slab.c 116 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
/*
 * 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
Simon Arlott's avatar
Simon Arlott committed
29
 * slabs and you must pass objects with the same initializations to
Linus Torvalds's avatar
Linus Torvalds committed
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
 * 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.
 *
Andrew Morton's avatar
Andrew Morton committed
53
 * The c_cpuarray may not be read with enabled local interrupts -
Linus Torvalds's avatar
Linus Torvalds committed
54
55
56
57
 * 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
 */

#include	<linux/slab.h>
#include	<linux/mm.h>
91
#include	<linux/poison.h>
Linus Torvalds's avatar
Linus Torvalds committed
92
93
94
95
96
#include	<linux/swap.h>
#include	<linux/cache.h>
#include	<linux/interrupt.h>
#include	<linux/init.h>
#include	<linux/compiler.h>
97
#include	<linux/cpuset.h>
98
#include	<linux/proc_fs.h>
Linus Torvalds's avatar
Linus Torvalds committed
99
100
101
102
103
104
#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>
105
#include	<linux/kmemtrace.h>
Linus Torvalds's avatar
Linus Torvalds committed
106
#include	<linux/rcupdate.h>
107
#include	<linux/string.h>
108
#include	<linux/uaccess.h>
109
#include	<linux/nodemask.h>
110
#include	<linux/mempolicy.h>
Ingo Molnar's avatar
Ingo Molnar committed
111
#include	<linux/mutex.h>
112
#include	<linux/fault-inject.h>
Ingo Molnar's avatar
Ingo Molnar committed
113
#include	<linux/rtmutex.h>
114
#include	<linux/reciprocal_div.h>
115
#include	<linux/debugobjects.h>
Linus Torvalds's avatar
Linus Torvalds committed
116
117
118
119
120
121

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

/*
122
 * DEBUG	- 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
Linus Torvalds's avatar
Linus Torvalds committed
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
 *		  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 *)
David Woodhouse's avatar
David Woodhouse committed
143
#define	REDZONE_ALIGN		max(BYTES_PER_WORD, __alignof__(unsigned long long))
Linus Torvalds's avatar
Linus Torvalds committed
144
145
146
147
148
149
150

#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
151
152
153
 * alignment larger than the alignment of a 64-bit integer.
 * ARCH_KMALLOC_MINALIGN allows that.
 * Note that increasing this value may disable some debug features.
Linus Torvalds's avatar
Linus Torvalds committed
154
 */
155
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
Linus Torvalds's avatar
Linus Torvalds committed
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
#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
175
# define CREATE_MASK	(SLAB_RED_ZONE | \
Linus Torvalds's avatar
Linus Torvalds committed
176
			 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
177
			 SLAB_CACHE_DMA | \
178
			 SLAB_STORE_USER | \
Linus Torvalds's avatar
Linus Torvalds committed
179
			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
180
181
			 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
			 SLAB_DEBUG_OBJECTS)
Linus Torvalds's avatar
Linus Torvalds committed
182
#else
183
# define CREATE_MASK	(SLAB_HWCACHE_ALIGN | \
184
			 SLAB_CACHE_DMA | \
Linus Torvalds's avatar
Linus Torvalds committed
185
			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
186
187
			 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
			 SLAB_DEBUG_OBJECTS)
Linus Torvalds's avatar
Linus Torvalds committed
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
#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.
 */

209
typedef unsigned int kmem_bufctl_t;
Linus Torvalds's avatar
Linus Torvalds committed
210
211
#define BUFCTL_END	(((kmem_bufctl_t)(~0U))-0)
#define BUFCTL_FREE	(((kmem_bufctl_t)(~0U))-1)
212
213
#define	BUFCTL_ACTIVE	(((kmem_bufctl_t)(~0U))-2)
#define	SLAB_LIMIT	(((kmem_bufctl_t)(~0U))-3)
Linus Torvalds's avatar
Linus Torvalds committed
214
215
216
217
218
219
220
221
222

/*
 * 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 {
223
224
225
226
227
228
	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
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
};

/*
 * 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 {
248
	struct rcu_head head;
249
	struct kmem_cache *cachep;
250
	void *addr;
Linus Torvalds's avatar
Linus Torvalds committed
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
};

/*
 * 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;
270
	spinlock_t lock;
271
	void *entry[];	/*
Andrew Morton's avatar
Andrew Morton committed
272
273
274
275
			 * Must have this definition in here for the proper
			 * alignment of array_cache. Also simplifies accessing
			 * the entries.
			 */
Linus Torvalds's avatar
Linus Torvalds committed
276
277
};

Andrew Morton's avatar
Andrew Morton committed
278
279
280
/*
 * bootstrap: The caches do not work without cpuarrays anymore, but the
 * cpuarrays are allocated from the generic caches...
Linus Torvalds's avatar
Linus Torvalds committed
281
282
283
284
 */
#define BOOT_CPUCACHE_ENTRIES	1
struct arraycache_init {
	struct array_cache cache;
285
	void *entries[BOOT_CPUCACHE_ENTRIES];
Linus Torvalds's avatar
Linus Torvalds committed
286
287
288
};

/*
289
 * The slab lists for all objects.
Linus Torvalds's avatar
Linus Torvalds committed
290
291
 */
struct kmem_list3 {
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 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 */
301
302
	unsigned long next_reap;	/* updated without locking */
	int free_touched;		/* updated without locking */
Linus Torvalds's avatar
Linus Torvalds committed
303
304
};

305
306
307
/*
 * Need this for bootstrapping a per node allocator.
 */
308
#define NUM_INIT_LISTS (3 * MAX_NUMNODES)
309
310
struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
#define	CACHE_CACHE 0
311
312
#define	SIZE_AC MAX_NUMNODES
#define	SIZE_L3 (2 * MAX_NUMNODES)
313

314
315
316
317
static int drain_freelist(struct kmem_cache *cache,
			struct kmem_list3 *l3, int tofree);
static void free_block(struct kmem_cache *cachep, void **objpp, int len,
			int node);
318
static int enable_cpucache(struct kmem_cache *cachep);
319
static void cache_reap(struct work_struct *unused);
320

321
/*
Andrew Morton's avatar
Andrew Morton committed
322
323
 * This function must be completely optimized away if a constant is passed to
 * it.  Mostly the same as what is in linux/slab.h except it returns an index.
324
 */
325
static __always_inline int index_of(const size_t size)
326
{
327
328
	extern void __bad_size(void);

329
330
331
332
333
334
335
336
	if (__builtin_constant_p(size)) {
		int i = 0;

#define CACHE(x) \
	if (size <=x) \
		return i; \
	else \
		i++;
337
#include <linux/kmalloc_sizes.h>
338
#undef CACHE
339
		__bad_size();
340
	} else
341
		__bad_size();
342
343
344
	return 0;
}

345
346
static int slab_early_init = 1;

347
348
#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
349

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

Andrew Morton's avatar
Andrew Morton committed
363
364
365
366
#define MAKE_LIST(cachep, listp, slab, nodeid)				\
	do {								\
		INIT_LIST_HEAD(listp);					\
		list_splice(&(cachep->nodelists[nodeid]->slab), listp);	\
367
368
	} while (0)

Andrew Morton's avatar
Andrew Morton committed
369
370
#define	MAKE_ALL_LISTS(cachep, ptr, nodeid)				\
	do {								\
371
372
373
374
	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
375
376

/*
377
 * struct kmem_cache
Linus Torvalds's avatar
Linus Torvalds committed
378
379
380
 *
 * manages a cache.
 */
381

382
struct kmem_cache {
Linus Torvalds's avatar
Linus Torvalds committed
383
/* 1) per-cpu data, touched during every alloc/free */
384
	struct array_cache *array[NR_CPUS];
385
/* 2) Cache tunables. Protected by cache_chain_mutex */
386
387
388
	unsigned int batchcount;
	unsigned int limit;
	unsigned int shared;
389

390
	unsigned int buffer_size;
391
	u32 reciprocal_buffer_size;
392
393
/* 3) touched by every alloc & free from the backend */

Andrew Morton's avatar
Andrew Morton committed
394
395
	unsigned int flags;		/* constant flags */
	unsigned int num;		/* # of objs per slab */
Linus Torvalds's avatar
Linus Torvalds committed
396

397
/* 4) cache_grow/shrink */
Linus Torvalds's avatar
Linus Torvalds committed
398
	/* order of pgs per slab (2^n) */
399
	unsigned int gfporder;
Linus Torvalds's avatar
Linus Torvalds committed
400
401

	/* force GFP flags, e.g. GFP_DMA */
402
	gfp_t gfpflags;
Linus Torvalds's avatar
Linus Torvalds committed
403

Andrew Morton's avatar
Andrew Morton committed
404
	size_t colour;			/* cache colouring range */
405
	unsigned int colour_off;	/* colour offset */
406
	struct kmem_cache *slabp_cache;
407
	unsigned int slab_size;
Andrew Morton's avatar
Andrew Morton committed
408
	unsigned int dflags;		/* dynamic flags */
Linus Torvalds's avatar
Linus Torvalds committed
409
410

	/* constructor func */
411
	void (*ctor)(void *obj);
Linus Torvalds's avatar
Linus Torvalds committed
412

413
/* 5) cache creation/removal */
414
415
	const char *name;
	struct list_head next;
Linus Torvalds's avatar
Linus Torvalds committed
416

417
/* 6) statistics */
Linus Torvalds's avatar
Linus Torvalds committed
418
#if STATS
419
420
421
422
423
424
425
426
427
	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;
428
	unsigned long node_overflow;
429
430
431
432
	atomic_t allochit;
	atomic_t allocmiss;
	atomic_t freehit;
	atomic_t freemiss;
Linus Torvalds's avatar
Linus Torvalds committed
433
434
#endif
#if DEBUG
435
436
437
438
439
440
441
442
	/*
	 * 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
443
#endif
Eric Dumazet's avatar
Eric Dumazet committed
444
445
446
447
448
449
450
451
452
453
454
	/*
	 * We put nodelists[] at the end of kmem_cache, because we want to size
	 * this array to nr_node_ids slots instead of MAX_NUMNODES
	 * (see kmem_cache_init())
	 * We still use [MAX_NUMNODES] and not [1] or [0] because cache_cache
	 * is statically defined, so we reserve the max number of nodes.
	 */
	struct kmem_list3 *nodelists[MAX_NUMNODES];
	/*
	 * Do not add fields after nodelists[]
	 */
Linus Torvalds's avatar
Linus Torvalds committed
455
456
457
458
459
460
};

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

#define BATCHREFILL_LIMIT	16
Andrew Morton's avatar
Andrew Morton committed
461
462
463
/*
 * Optimization question: fewer reaps means less probability for unnessary
 * cpucache drain/refill cycles.
Linus Torvalds's avatar
Linus Torvalds committed
464
 *
Adrian Bunk's avatar
Adrian Bunk committed
465
 * OTOH the cpuarrays can contain lots of objects,
Linus Torvalds's avatar
Linus Torvalds committed
466
467
468
469
470
471
472
473
474
475
 * 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++)
476
#define	STATS_ADD_REAPED(x,y)	((x)->reaped += (y))
Andrew Morton's avatar
Andrew Morton committed
477
478
479
480
481
#define	STATS_SET_HIGH(x)						\
	do {								\
		if ((x)->num_active > (x)->high_mark)			\
			(x)->high_mark = (x)->num_active;		\
	} while (0)
Linus Torvalds's avatar
Linus Torvalds committed
482
483
#define	STATS_INC_ERR(x)	((x)->errors++)
#define	STATS_INC_NODEALLOCS(x)	((x)->node_allocs++)
484
#define	STATS_INC_NODEFREES(x)	((x)->node_frees++)
485
#define STATS_INC_ACOVERFLOW(x)   ((x)->node_overflow++)
Andrew Morton's avatar
Andrew Morton committed
486
487
488
489
490
#define	STATS_SET_FREEABLE(x, i)					\
	do {								\
		if ((x)->max_freeable < i)				\
			(x)->max_freeable = i;				\
	} while (0)
Linus Torvalds's avatar
Linus Torvalds committed
491
492
493
494
495
496
497
498
499
#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)
500
#define	STATS_ADD_REAPED(x,y)	do { } while (0)
Linus Torvalds's avatar
Linus Torvalds committed
501
502
503
#define	STATS_SET_HIGH(x)	do { } while (0)
#define	STATS_INC_ERR(x)	do { } while (0)
#define	STATS_INC_NODEALLOCS(x)	do { } while (0)
504
#define	STATS_INC_NODEFREES(x)	do { } while (0)
505
#define STATS_INC_ACOVERFLOW(x)   do { } while (0)
Andrew Morton's avatar
Andrew Morton committed
506
#define	STATS_SET_FREEABLE(x, i) do { } while (0)
Linus Torvalds's avatar
Linus Torvalds committed
507
508
509
510
511
512
513
514
#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

Andrew Morton's avatar
Andrew Morton committed
515
516
/*
 * memory layout of objects:
Linus Torvalds's avatar
Linus Torvalds committed
517
 * 0		: objp
518
 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
Linus Torvalds's avatar
Linus Torvalds committed
519
520
 * 		the end of an object is aligned with the end of the real
 * 		allocation. Catches writes behind the end of the allocation.
521
 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
Linus Torvalds's avatar
Linus Torvalds committed
522
 * 		redzone word.
523
524
 * cachep->obj_offset: The real object.
 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
Andrew Morton's avatar
Andrew Morton committed
525
526
 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
 *					[BYTES_PER_WORD long]
Linus Torvalds's avatar
Linus Torvalds committed
527
 */
528
static int obj_offset(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
529
{
530
	return cachep->obj_offset;
Linus Torvalds's avatar
Linus Torvalds committed
531
532
}

533
static int obj_size(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
534
{
535
	return cachep->obj_size;
Linus Torvalds's avatar
Linus Torvalds committed
536
537
}

538
static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
539
540
{
	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
541
542
	return (unsigned long long*) (objp + obj_offset(cachep) -
				      sizeof(unsigned long long));
Linus Torvalds's avatar
Linus Torvalds committed
543
544
}

545
static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
546
547
548
{
	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
	if (cachep->flags & SLAB_STORE_USER)
549
550
		return (unsigned long long *)(objp + cachep->buffer_size -
					      sizeof(unsigned long long) -
David Woodhouse's avatar
David Woodhouse committed
551
					      REDZONE_ALIGN);
552
553
	return (unsigned long long *) (objp + cachep->buffer_size -
				       sizeof(unsigned long long));
Linus Torvalds's avatar
Linus Torvalds committed
554
555
}

556
static void **dbg_userword(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
557
558
{
	BUG_ON(!(cachep->flags & SLAB_STORE_USER));
559
	return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
Linus Torvalds's avatar
Linus Torvalds committed
560
561
562
563
}

#else

564
565
#define obj_offset(x)			0
#define obj_size(cachep)		(cachep->buffer_size)
566
567
#define dbg_redzone1(cachep, objp)	({BUG(); (unsigned long long *)NULL;})
#define dbg_redzone2(cachep, objp)	({BUG(); (unsigned long long *)NULL;})
Linus Torvalds's avatar
Linus Torvalds committed
568
569
570
571
#define dbg_userword(cachep, objp)	({BUG(); (void **)NULL;})

#endif

572
573
574
575
576
577
578
579
#ifdef CONFIG_KMEMTRACE
size_t slab_buffer_size(struct kmem_cache *cachep)
{
	return cachep->buffer_size;
}
EXPORT_SYMBOL(slab_buffer_size);
#endif

Linus Torvalds's avatar
Linus Torvalds committed
580
581
582
583
584
585
586
/*
 * 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;

Andrew Morton's avatar
Andrew Morton committed
587
588
589
590
/*
 * Functions for storing/retrieving the cachep and or slab from the page
 * allocator.  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.
Linus Torvalds's avatar
Linus Torvalds committed
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)
{
599
	page = compound_head(page);
600
	BUG_ON(!PageSlab(page));
601
602
603
604
605
606
607
608
609
610
	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)
{
611
	BUG_ON(!PageSlab(page));
612
613
	return (struct slab *)page->lru.prev;
}
Linus Torvalds's avatar
Linus Torvalds committed
614

615
616
static inline struct kmem_cache *virt_to_cache(const void *obj)
{
617
	struct page *page = virt_to_head_page(obj);
618
619
620
621
622
	return page_get_cache(page);
}

static inline struct slab *virt_to_slab(const void *obj)
{
623
	struct page *page = virt_to_head_page(obj);
624
625
626
	return page_get_slab(page);
}

627
628
629
630
631
632
static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
				 unsigned int idx)
{
	return slab->s_mem + cache->buffer_size * idx;
}

633
634
635
636
637
638
639
640
/*
 * We want to avoid an expensive divide : (offset / cache->buffer_size)
 *   Using the fact that buffer_size is a constant for a particular cache,
 *   we can replace (offset / cache->buffer_size) by
 *   reciprocal_divide(offset, cache->reciprocal_buffer_size)
 */
static inline unsigned int obj_to_index(const struct kmem_cache *cache,
					const struct slab *slab, void *obj)
641
{
642
643
	u32 offset = (obj - slab->s_mem);
	return reciprocal_divide(offset, cache->reciprocal_buffer_size);
644
645
}

Andrew Morton's avatar
Andrew Morton committed
646
647
648
/*
 * These are the default caches for kmalloc. Custom caches can have other sizes.
 */
Linus Torvalds's avatar
Linus Torvalds committed
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
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>
666
	{NULL,}
Linus Torvalds's avatar
Linus Torvalds committed
667
668
669
670
#undef CACHE
};

static struct arraycache_init initarray_cache __initdata =
671
    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
Linus Torvalds's avatar
Linus Torvalds committed
672
static struct arraycache_init initarray_generic =
673
    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
Linus Torvalds's avatar
Linus Torvalds committed
674
675

/* internal cache of cache description objs */
676
static struct kmem_cache cache_cache = {
677
678
679
	.batchcount = 1,
	.limit = BOOT_CPUCACHE_ENTRIES,
	.shared = 1,
680
	.buffer_size = sizeof(struct kmem_cache),
681
	.name = "kmem_cache",
Linus Torvalds's avatar
Linus Torvalds committed
682
683
};

684
685
#define BAD_ALIEN_MAGIC 0x01020304ul

686
687
688
689
690
691
692
693
#ifdef CONFIG_LOCKDEP

/*
 * Slab sometimes uses the kmalloc slabs to store the slab headers
 * for other slabs "off slab".
 * The locking for this is tricky in that it nests within the locks
 * of all other slabs in a few places; to deal with this special
 * locking we put on-slab caches into a separate lock-class.
694
695
696
697
 *
 * We set lock class for alien array caches which are up during init.
 * The lock annotation will be lost if all cpus of a node goes down and
 * then comes back up during hotplug
698
 */
699
700
701
702
static struct lock_class_key on_slab_l3_key;
static struct lock_class_key on_slab_alc_key;

static inline void init_lock_keys(void)
703
704
705

{
	int q;
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
	struct cache_sizes *s = malloc_sizes;

	while (s->cs_size != ULONG_MAX) {
		for_each_node(q) {
			struct array_cache **alc;
			int r;
			struct kmem_list3 *l3 = s->cs_cachep->nodelists[q];
			if (!l3 || OFF_SLAB(s->cs_cachep))
				continue;
			lockdep_set_class(&l3->list_lock, &on_slab_l3_key);
			alc = l3->alien;
			/*
			 * FIXME: This check for BAD_ALIEN_MAGIC
			 * should go away when common slab code is taught to
			 * work even without alien caches.
			 * Currently, non NUMA code returns BAD_ALIEN_MAGIC
			 * for alloc_alien_cache,
			 */
			if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
				continue;
			for_each_node(r) {
				if (alc[r])
					lockdep_set_class(&alc[r]->lock,
					     &on_slab_alc_key);
			}
		}
		s++;
733
734
735
	}
}
#else
736
static inline void init_lock_keys(void)
737
738
739
740
{
}
#endif

741
/*
742
 * Guard access to the cache-chain.
743
 */
Ingo Molnar's avatar
Ingo Molnar committed
744
static DEFINE_MUTEX(cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
745
746
747
748
749
750
751
752
static struct list_head cache_chain;

/*
 * chicken and egg problem: delay the per-cpu array allocation
 * until the general caches are up.
 */
static enum {
	NONE,
753
754
	PARTIAL_AC,
	PARTIAL_L3,
Linus Torvalds's avatar
Linus Torvalds committed
755
756
757
	FULL
} g_cpucache_up;

758
759
760
761
762
763
764
765
/*
 * used by boot code to determine if it can use slab based allocator
 */
int slab_is_available(void)
{
	return g_cpucache_up == FULL;
}

766
static DEFINE_PER_CPU(struct delayed_work, reap_work);
Linus Torvalds's avatar
Linus Torvalds committed
767

768
static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
769
770
771
772
{
	return cachep->array[smp_processor_id()];
}

Andrew Morton's avatar
Andrew Morton committed
773
774
static inline struct kmem_cache *__find_general_cachep(size_t size,
							gfp_t gfpflags)
Linus Torvalds's avatar
Linus Torvalds committed
775
776
777
778
779
{
	struct cache_sizes *csizep = malloc_sizes;

#if DEBUG
	/* This happens if someone tries to call
780
781
782
	 * kmem_cache_create(), or __kmalloc(), before
	 * the generic caches are initialized.
	 */
783
	BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
Linus Torvalds's avatar
Linus Torvalds committed
784
#endif
785
786
787
	if (!size)
		return ZERO_SIZE_PTR;

Linus Torvalds's avatar
Linus Torvalds committed
788
789
790
791
	while (size > csizep->cs_size)
		csizep++;

	/*
792
	 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
Linus Torvalds's avatar
Linus Torvalds committed
793
794
795
	 * has cs_{dma,}cachep==NULL. Thus no special case
	 * for large kmalloc calls required.
	 */
796
#ifdef CONFIG_ZONE_DMA
Linus Torvalds's avatar
Linus Torvalds committed
797
798
	if (unlikely(gfpflags & GFP_DMA))
		return csizep->cs_dmacachep;
799
#endif
Linus Torvalds's avatar
Linus Torvalds committed
800
801
802
	return csizep->cs_cachep;
}

803
static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
804
805
806
807
{
	return __find_general_cachep(size, gfpflags);
}

808
static size_t slab_mgmt_size(size_t nr_objs, size_t align)
Linus Torvalds's avatar
Linus Torvalds committed
809
{
810
811
	return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
}
Linus Torvalds's avatar
Linus Torvalds committed
812

Andrew Morton's avatar
Andrew Morton committed
813
814
815
/*
 * Calculate the number of objects and left-over bytes for a given buffer size.
 */
816
817
818
819
820
821
822
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
823

824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
	/*
	 * 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
872
873
}

874
#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
Linus Torvalds's avatar
Linus Torvalds committed
875

Andrew Morton's avatar
Andrew Morton committed
876
877
static void __slab_error(const char *function, struct kmem_cache *cachep,
			char *msg)
Linus Torvalds's avatar
Linus Torvalds committed
878
879
{
	printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
880
	       function, cachep->name, msg);
Linus Torvalds's avatar
Linus Torvalds committed
881
882
883
	dump_stack();
}

884
885
886
887
888
889
890
891
892
/*
 * By default on NUMA we use alien caches to stage the freeing of
 * objects allocated from other nodes. This causes massive memory
 * inefficiencies when using fake NUMA setup to split memory into a
 * large number of small nodes, so it can be disabled on the command
 * line
  */

static int use_alien_caches __read_mostly = 1;
893
static int numa_platform __read_mostly = 1;
894
895
896
897
898
899
900
static int __init noaliencache_setup(char *s)
{
	use_alien_caches = 0;
	return 1;
}
__setup("noaliencache", noaliencache_setup);

901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
#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)
916
		node = first_node(node_online_map);
917

918
	per_cpu(reap_node, cpu) = node;
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
}

static void next_reap_node(void)
{
	int node = __get_cpu_var(reap_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
936
937
938
939
940
941
942
/*
 * 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.
 */
943
static void __cpuinit start_cpu_timer(int cpu)
Linus Torvalds's avatar
Linus Torvalds committed
944
{
945
	struct delayed_work *reap_work = &per_cpu(reap_work, cpu);
Linus Torvalds's avatar
Linus Torvalds committed
946
947
948
949
950
951

	/*
	 * When this gets called from do_initcalls via cpucache_init(),
	 * init_workqueues() has already run, so keventd will be setup
	 * at that time.
	 */
952
	if (keventd_up() && reap_work->work.func == NULL) {
953
		init_reap_node(cpu);
954
		INIT_DELAYED_WORK(reap_work, cache_reap);
955
956
		schedule_delayed_work_on(cpu, reap_work,
					__round_jiffies_relative(HZ, cpu));
Linus Torvalds's avatar
Linus Torvalds committed
957
958
959
	}
}

960
static struct array_cache *alloc_arraycache(int node, int entries,
961
					    int batchcount)
Linus Torvalds's avatar
Linus Torvalds committed
962
{
963
	int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
Linus Torvalds's avatar
Linus Torvalds committed
964
965
	struct array_cache *nc = NULL;

966
	nc = kmalloc_node(memsize, GFP_KERNEL, node);
Linus Torvalds's avatar
Linus Torvalds committed
967
968
969
970
971
	if (nc) {
		nc->avail = 0;
		nc->limit = entries;
		nc->batchcount = batchcount;
		nc->touched = 0;
972
		spin_lock_init(&nc->lock);
Linus Torvalds's avatar
Linus Torvalds committed
973
974
975
976
	}
	return nc;
}

977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/*
 * Transfer objects in one arraycache to another.
 * Locking must be handled by the caller.
 *
 * Return the number of entries transferred.
 */
static int transfer_objects(struct array_cache *to,
		struct array_cache *from, unsigned int max)
{
	/* Figure out how many entries to transfer */
	int nr = min(min(from->avail, max), to->limit - to->avail);

	if (!nr)
		return 0;

	memcpy(to->entry + to->avail, from->entry + from->avail -nr,
			sizeof(void *) *nr);

	from->avail -= nr;
	to->avail += nr;
	to->touched = 1;
	return nr;
}

1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
#ifndef CONFIG_NUMA

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

static inline struct array_cache **alloc_alien_cache(int node, int limit)
{
	return (struct array_cache **)BAD_ALIEN_MAGIC;
}

static inline void free_alien_cache(struct array_cache **ac_ptr)
{
}

static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
{
	return 0;
}

static inline void *alternate_node_alloc(struct kmem_cache *cachep,
		gfp_t flags)
{
	return NULL;
}

1026
static inline void *____cache_alloc_node(struct kmem_cache *cachep,
1027
1028
1029
1030
1031
1032
1033
		 gfp_t flags, int nodeid)
{
	return NULL;
}

#else	/* CONFIG_NUMA */

1034
static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
1035
static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
1036

Pekka Enberg's avatar
Pekka Enberg committed
1037
static struct array_cache **alloc_alien_cache(int node, int limit)
1038
1039
{
	struct array_cache **ac_ptr;
1040
	int memsize = sizeof(void *) * nr_node_ids;
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
	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]) {
1054
				for (i--; i >= 0; i--)
1055
1056
1057
1058
1059
1060
1061
1062
1063
					kfree(ac_ptr[i]);
				kfree(ac_ptr);
				return NULL;
			}
		}
	}
	return ac_ptr;
}

Pekka Enberg's avatar
Pekka Enberg committed
1064
static void free_alien_cache(struct array_cache **ac_ptr)
1065
1066
1067
1068
1069
1070
{
	int i;

	if (!ac_ptr)
		return;
	for_each_node(i)
1071
	    kfree(ac_ptr[i]);
1072
1073
1074
	kfree(ac_ptr);
}

1075
static void __drain_alien_cache(struct kmem_cache *cachep,
Pekka Enberg's avatar
Pekka Enberg committed
1076
				struct array_cache *ac, int node)
1077
1078
1079
1080
1081
{
	struct kmem_list3 *rl3 = cachep->nodelists[node];

	if (ac->avail) {
		spin_lock(&rl3->list_lock);
1082
1083
1084
1085
1086
		/*
		 * Stuff objects into the remote nodes shared array first.
		 * That way we could avoid the overhead of putting the objects
		 * into the free lists and getting them back later.
		 */
1087
1088
		if (rl3->shared)
			transfer_objects(rl3->shared, ac, ac->limit);
1089

1090
		free_block(cachep, ac->entry, ac->avail, node);
1091
1092
1093
1094
1095
		ac->avail = 0;
		spin_unlock(&rl3->list_lock);
	}
}

1096
1097
1098
1099
1100
1101
1102
1103
1104
/*
 * 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];
1105
1106

		if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1107
1108
1109
1110
1111
1112
			__drain_alien_cache(cachep, ac, node);
			spin_unlock_irq(&ac->lock);
		}
	}
}

Andrew Morton's avatar
Andrew Morton committed
1113
1114
static void drain_alien_cache(struct kmem_cache *cachep,
				struct array_cache **alien)
1115
{
1116
	int i = 0;
1117
1118
1119
1120
	struct array_cache *ac;
	unsigned long flags;

	for_each_online_node(i) {
1121
		ac = alien[i];
1122
1123
1124
1125
1126
1127
1128
		if (ac) {
			spin_lock_irqsave(&ac->lock, flags);
			__drain_alien_cache(cachep, ac, i);
			spin_unlock_irqrestore(&ac->lock, flags);
		}
	}
}
1129

1130
static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1131
1132
1133
1134
1135
{
	struct slab *slabp = virt_to_slab(objp);
	int nodeid = slabp->nodeid;
	struct kmem_list3 *l3;
	struct array_cache *alien = NULL;
1136
1137
1138
	int node;

	node = numa_node_id();
1139
1140
1141
1142
1143

	/*
	 * Make sure we are not freeing a object from another node to the array
	 * cache on this cpu.
	 */
1144
	if (likely(slabp->nodeid == node))
1145
1146
		return 0;

1147
	l3 = cachep->nodelists[node];
1148
1149
1150
	STATS_INC_NODEFREES(cachep);
	if (l3->alien && l3->alien[nodeid]) {
		alien = l3->alien[nodeid];
1151
		spin_lock(&alien->lock);
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
		if (unlikely(alien->avail == alien->limit)) {
			STATS_INC_ACOVERFLOW(cachep);
			__drain_alien_cache(cachep, alien, nodeid);
		}
		alien->entry[alien->avail++] = objp;
		spin_unlock(&alien->lock);
	} else {
		spin_lock(&(cachep->nodelists[nodeid])->list_lock);
		free_block(cachep, &objp, 1, nodeid);
		spin_unlock(&(cachep->nodelists[nodeid])->list_lock);
	}
	return 1;
}
1165
1166
#endif

1167
1168
1169
1170
1171
static void __cpuinit cpuup_canceled(long cpu)
{
	struct kmem_cache *cachep;
	struct kmem_list3 *l3 = NULL;
	int node = cpu_to_node(cpu);
1172
	const struct cpumask *mask = cpumask_of_node(node);
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193

	list_for_each_entry(cachep, &cache_chain, next) {
		struct array_cache *nc;
		struct array_cache *shared;
		struct array_cache **alien;

		/* cpu is dead; no one can alloc from it. */
		nc = cachep->array[cpu];
		cachep->array[cpu] = NULL;
		l3 = cachep->nodelists[node];

		if (!l3)
			goto free_array_cache;

		spin_lock_irq(&l3->list_lock);

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

1194
		if (!cpus_empty(*mask)) {
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
			spin_unlock_irq(&l3->list_lock);
			goto free_array_cache;
		}

		shared = l3->shared;
		if (shared) {
			free_block(cachep, shared->entry,
				   shared->avail, node);
			l3->shared = NULL;
		}

		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);
		}
free_array_cache:
		kfree(nc);
	}
	/*
	 * 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;
		drain_freelist(cachep, l3, l3->free_objects);
	}
}

static int __cpuinit cpuup_prepare(long cpu)
Linus Torvalds's avatar
Linus Torvalds committed
1233
{
1234
	struct kmem_cache *cachep;
1235
1236
	struct kmem_list3 *l3 = NULL;
	int node = cpu_to_node(cpu);
1237
	const int memsize = sizeof(struct kmem_list3);
Linus Torvalds's avatar
Linus Torvalds committed
1238

1239
1240
1241
1242
1243
1244
1245
1246
	/*
	 * 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
	 */

	list_for_each_entry(cachep, &cache_chain, next) {
Andrew Morton's avatar
Andrew Morton committed
1247
		/*
1248
1249
1250
		 * Set up the size64 kmemlist for cpu before we can
		 * begin anything. Make sure some other cpu on this
		 * node has not already allocated this
1251
		 */
1252
1253
1254
1255
1256
1257
1258
		if (!cachep->nodelists[node]) {
			l3 = kmalloc_node(memsize, GFP_KERNEL, node);
			if (!l3)
				goto bad;
			kmem_list3_init(l3);
			l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
			    ((unsigned long)cachep) % REAPTIMEOUT_LIST3;
1259

Andrew Morton's avatar
Andrew Morton committed
1260
			/*
1261
1262
1263
			 * The l3s don't come and go as CPUs come and
			 * go.  cache_chain_mutex is sufficient
			 * protection here.
1264
			 */
1265
			cachep->nodelists[node] = l3;
1266
1267
		}

1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
		spin_lock_irq(&cachep->nodelists[node]->list_lock);
		cachep->nodelists[node]->free_limit =
			(1 + nr_cpus_node(node)) *
			cachep->batchcount + cachep->num;
		spin_unlock_irq(&cachep->nodelists[node]->list_lock);
	}

	/*
	 * Now we can go ahead with allocating the shared arrays and
	 * array caches
	 */
	list_for_each_entry(cachep, &cache_chain, next) {
		struct array_cache *nc;
		struct array_cache *shared = NULL;
		struct array_cache **alien = NULL;

		nc = alloc_arraycache(node, cachep->limit,
					cachep->batchcount);
		if (!nc)
			goto bad;
		if (cachep->shared) {
			shared = alloc_arraycache(node,
				cachep->shared * cachep->batchcount,
				0xbaadf00d);
1292
1293
			if (!shared) {
				kfree(nc);
Linus Torvalds's avatar
Linus Torvalds committed
1294
				goto bad;
1295
			}
1296
1297
1298
		}
		if (use_alien_caches) {
			alien = alloc_alien_cache(node, cachep->limit);
1299
1300
1301
			if (!alien) {
				kfree(shared);
				kfree(nc);
1302
				goto bad;
1303
			}
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
		}
		cachep->array[cpu] = nc;
		l3 = cachep->nodelists[node];
		BUG_ON(!l3);

		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;
		}
1318
#ifdef CONFIG_NUMA
1319
1320
1321
		if (!l3->alien) {
			l3->alien = alien;
			alien = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
1322
		}
1323
1324
1325
1326
1327
1328
1329
#endif
		spin_unlock_irq(&l3->list_lock);
		kfree(shared);
		free_alien_cache(alien);
	}
	return 0;
bad:
1330
	cpuup_canceled(cpu);
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
	return -ENOMEM;
}

static int __cpuinit cpuup_callback(struct notifier_block *nfb,
				    unsigned long action, void *hcpu)
{
	long cpu = (long)hcpu;
	int err = 0;

	switch (action) {
	case CPU_UP_PREPARE:
	case CPU_UP_PREPARE_FROZEN:
1343
		mutex_lock(&cache_chain_mutex);
1344
		err = cpuup_prepare(cpu);
1345
		mutex_unlock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1346
1347
		break;
	case CPU_ONLINE:
1348
	case CPU_ONLINE_FROZEN:
Linus Torvalds's avatar
Linus Torvalds committed
1349
1350
1351
		start_cpu_timer(cpu);
		break;
#ifdef CONFIG_HOTPLUG_CPU
1352
  	case CPU_DOWN_PREPARE:
1353
  	case CPU_DOWN_PREPARE_FROZEN: