slab.c 115 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
105
#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>
106
#include	<linux/string.h>
107
#include	<linux/uaccess.h>
108
#include	<linux/nodemask.h>
109
#include	<linux/mempolicy.h>
Ingo Molnar's avatar
Ingo Molnar committed
110
#include	<linux/mutex.h>
111
#include	<linux/fault-inject.h>
Ingo Molnar's avatar
Ingo Molnar committed
112
#include	<linux/rtmutex.h>
113
#include	<linux/reciprocal_div.h>
114
#include	<linux/debugobjects.h>
Linus Torvalds's avatar
Linus Torvalds committed
115
116
117
118
119
120

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

/*
121
 * DEBUG	- 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
Linus Torvalds's avatar
Linus Torvalds committed
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
 *		  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
142
#define	REDZONE_ALIGN		max(BYTES_PER_WORD, __alignof__(unsigned long long))
Linus Torvalds's avatar
Linus Torvalds committed
143
144
145
146
147
148
149

#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
150
151
152
 * 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
153
 */
154
#define ARCH_KMALLOC_MINALIGN __alignof__(unsigned long long)
Linus Torvalds's avatar
Linus Torvalds committed
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
#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
174
# define CREATE_MASK	(SLAB_RED_ZONE | \
Linus Torvalds's avatar
Linus Torvalds committed
175
			 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
176
			 SLAB_CACHE_DMA | \
177
			 SLAB_STORE_USER | \
Linus Torvalds's avatar
Linus Torvalds committed
178
			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
179
180
			 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
			 SLAB_DEBUG_OBJECTS)
Linus Torvalds's avatar
Linus Torvalds committed
181
#else
182
# define CREATE_MASK	(SLAB_HWCACHE_ALIGN | \
183
			 SLAB_CACHE_DMA | \
Linus Torvalds's avatar
Linus Torvalds committed
184
			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
185
186
			 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
			 SLAB_DEBUG_OBJECTS)
Linus Torvalds's avatar
Linus Torvalds committed
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
#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.
 */

208
typedef unsigned int kmem_bufctl_t;
Linus Torvalds's avatar
Linus Torvalds committed
209
210
#define BUFCTL_END	(((kmem_bufctl_t)(~0U))-0)
#define BUFCTL_FREE	(((kmem_bufctl_t)(~0U))-1)
211
212
#define	BUFCTL_ACTIVE	(((kmem_bufctl_t)(~0U))-2)
#define	SLAB_LIMIT	(((kmem_bufctl_t)(~0U))-3)
Linus Torvalds's avatar
Linus Torvalds committed
213
214
215
216
217
218
219
220
221

/*
 * 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 {
222
223
224
225
226
227
	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
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
};

/*
 * 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 {
247
	struct rcu_head head;
248
	struct kmem_cache *cachep;
249
	void *addr;
Linus Torvalds's avatar
Linus Torvalds committed
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
};

/*
 * 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;
269
	spinlock_t lock;
270
	void *entry[];	/*
Andrew Morton's avatar
Andrew Morton committed
271
272
273
274
			 * 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
275
276
};

Andrew Morton's avatar
Andrew Morton committed
277
278
279
/*
 * 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
280
281
282
283
 */
#define BOOT_CPUCACHE_ENTRIES	1
struct arraycache_init {
	struct array_cache cache;
284
	void *entries[BOOT_CPUCACHE_ENTRIES];
Linus Torvalds's avatar
Linus Torvalds committed
285
286
287
};

/*
288
 * The slab lists for all objects.
Linus Torvalds's avatar
Linus Torvalds committed
289
290
 */
struct kmem_list3 {
291
292
293
294
295
	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;
296
	unsigned int colour_next;	/* Per-node cache coloring */
297
298
299
	spinlock_t list_lock;
	struct array_cache *shared;	/* shared per node */
	struct array_cache **alien;	/* on other nodes */
300
301
	unsigned long next_reap;	/* updated without locking */
	int free_touched;		/* updated without locking */
Linus Torvalds's avatar
Linus Torvalds committed
302
303
};

304
305
306
/*
 * Need this for bootstrapping a per node allocator.
 */
307
#define NUM_INIT_LISTS (3 * MAX_NUMNODES)
308
309
struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
#define	CACHE_CACHE 0
310
311
#define	SIZE_AC MAX_NUMNODES
#define	SIZE_L3 (2 * MAX_NUMNODES)
312

313
314
315
316
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);
317
static int enable_cpucache(struct kmem_cache *cachep);
318
static void cache_reap(struct work_struct *unused);
319

320
/*
Andrew Morton's avatar
Andrew Morton committed
321
322
 * 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.
323
 */
324
static __always_inline int index_of(const size_t size)
325
{
326
327
	extern void __bad_size(void);

328
329
330
331
332
333
334
335
	if (__builtin_constant_p(size)) {
		int i = 0;

#define CACHE(x) \
	if (size <=x) \
		return i; \
	else \
		i++;
336
#include <linux/kmalloc_sizes.h>
337
#undef CACHE
338
		__bad_size();
339
	} else
340
		__bad_size();
341
342
343
	return 0;
}

344
345
static int slab_early_init = 1;

346
347
#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
348

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

Andrew Morton's avatar
Andrew Morton committed
362
363
364
365
#define MAKE_LIST(cachep, listp, slab, nodeid)				\
	do {								\
		INIT_LIST_HEAD(listp);					\
		list_splice(&(cachep->nodelists[nodeid]->slab), listp);	\
366
367
	} while (0)

Andrew Morton's avatar
Andrew Morton committed
368
369
#define	MAKE_ALL_LISTS(cachep, ptr, nodeid)				\
	do {								\
370
371
372
373
	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
374
375

/*
376
 * struct kmem_cache
Linus Torvalds's avatar
Linus Torvalds committed
377
378
379
 *
 * manages a cache.
 */
380

381
struct kmem_cache {
Linus Torvalds's avatar
Linus Torvalds committed
382
/* 1) per-cpu data, touched during every alloc/free */
383
	struct array_cache *array[NR_CPUS];
384
/* 2) Cache tunables. Protected by cache_chain_mutex */
385
386
387
	unsigned int batchcount;
	unsigned int limit;
	unsigned int shared;
388

389
	unsigned int buffer_size;
390
	u32 reciprocal_buffer_size;
391
392
/* 3) touched by every alloc & free from the backend */

Andrew Morton's avatar
Andrew Morton committed
393
394
	unsigned int flags;		/* constant flags */
	unsigned int num;		/* # of objs per slab */
Linus Torvalds's avatar
Linus Torvalds committed
395

396
/* 4) cache_grow/shrink */
Linus Torvalds's avatar
Linus Torvalds committed
397
	/* order of pgs per slab (2^n) */
398
	unsigned int gfporder;
Linus Torvalds's avatar
Linus Torvalds committed
399
400

	/* force GFP flags, e.g. GFP_DMA */
401
	gfp_t gfpflags;
Linus Torvalds's avatar
Linus Torvalds committed
402

Andrew Morton's avatar
Andrew Morton committed
403
	size_t colour;			/* cache colouring range */
404
	unsigned int colour_off;	/* colour offset */
405
	struct kmem_cache *slabp_cache;
406
	unsigned int slab_size;
Andrew Morton's avatar
Andrew Morton committed
407
	unsigned int dflags;		/* dynamic flags */
Linus Torvalds's avatar
Linus Torvalds committed
408
409

	/* constructor func */
410
	void (*ctor)(void *obj);
Linus Torvalds's avatar
Linus Torvalds committed
411

412
/* 5) cache creation/removal */
413
414
	const char *name;
	struct list_head next;
Linus Torvalds's avatar
Linus Torvalds committed
415

416
/* 6) statistics */
Linus Torvalds's avatar
Linus Torvalds committed
417
#if STATS
418
419
420
421
422
423
424
425
426
	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;
427
	unsigned long node_overflow;
428
429
430
431
	atomic_t allochit;
	atomic_t allocmiss;
	atomic_t freehit;
	atomic_t freemiss;
Linus Torvalds's avatar
Linus Torvalds committed
432
433
#endif
#if DEBUG
434
435
436
437
438
439
440
441
	/*
	 * 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
442
#endif
Eric Dumazet's avatar
Eric Dumazet committed
443
444
445
446
447
448
449
450
451
452
453
	/*
	 * 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
454
455
456
457
458
459
};

#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
460
461
462
/*
 * Optimization question: fewer reaps means less probability for unnessary
 * cpucache drain/refill cycles.
Linus Torvalds's avatar
Linus Torvalds committed
463
 *
Adrian Bunk's avatar
Adrian Bunk committed
464
 * OTOH the cpuarrays can contain lots of objects,
Linus Torvalds's avatar
Linus Torvalds committed
465
466
467
468
469
470
471
472
473
474
 * 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++)
475
#define	STATS_ADD_REAPED(x,y)	((x)->reaped += (y))
Andrew Morton's avatar
Andrew Morton committed
476
477
478
479
480
#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
481
482
#define	STATS_INC_ERR(x)	((x)->errors++)
#define	STATS_INC_NODEALLOCS(x)	((x)->node_allocs++)
483
#define	STATS_INC_NODEFREES(x)	((x)->node_frees++)
484
#define STATS_INC_ACOVERFLOW(x)   ((x)->node_overflow++)
Andrew Morton's avatar
Andrew Morton committed
485
486
487
488
489
#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
490
491
492
493
494
495
496
497
498
#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)
499
#define	STATS_ADD_REAPED(x,y)	do { } while (0)
Linus Torvalds's avatar
Linus Torvalds committed
500
501
502
#define	STATS_SET_HIGH(x)	do { } while (0)
#define	STATS_INC_ERR(x)	do { } while (0)
#define	STATS_INC_NODEALLOCS(x)	do { } while (0)
503
#define	STATS_INC_NODEFREES(x)	do { } while (0)
504
#define STATS_INC_ACOVERFLOW(x)   do { } while (0)
Andrew Morton's avatar
Andrew Morton committed
505
#define	STATS_SET_FREEABLE(x, i) do { } while (0)
Linus Torvalds's avatar
Linus Torvalds committed
506
507
508
509
510
511
512
513
#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
514
515
/*
 * memory layout of objects:
Linus Torvalds's avatar
Linus Torvalds committed
516
 * 0		: objp
517
 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
Linus Torvalds's avatar
Linus Torvalds committed
518
519
 * 		the end of an object is aligned with the end of the real
 * 		allocation. Catches writes behind the end of the allocation.
520
 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
Linus Torvalds's avatar
Linus Torvalds committed
521
 * 		redzone word.
522
523
 * 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
524
525
 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address
 *					[BYTES_PER_WORD long]
Linus Torvalds's avatar
Linus Torvalds committed
526
 */
527
static int obj_offset(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
528
{
529
	return cachep->obj_offset;
Linus Torvalds's avatar
Linus Torvalds committed
530
531
}

532
static int obj_size(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
533
{
534
	return cachep->obj_size;
Linus Torvalds's avatar
Linus Torvalds committed
535
536
}

537
static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
538
539
{
	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
540
541
	return (unsigned long long*) (objp + obj_offset(cachep) -
				      sizeof(unsigned long long));
Linus Torvalds's avatar
Linus Torvalds committed
542
543
}

544
static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
545
546
547
{
	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
	if (cachep->flags & SLAB_STORE_USER)
548
549
		return (unsigned long long *)(objp + cachep->buffer_size -
					      sizeof(unsigned long long) -
David Woodhouse's avatar
David Woodhouse committed
550
					      REDZONE_ALIGN);
551
552
	return (unsigned long long *) (objp + cachep->buffer_size -
				       sizeof(unsigned long long));
Linus Torvalds's avatar
Linus Torvalds committed
553
554
}

555
static void **dbg_userword(struct kmem_cache *cachep, void *objp)
Linus Torvalds's avatar
Linus Torvalds committed
556
557
{
	BUG_ON(!(cachep->flags & SLAB_STORE_USER));
558
	return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD);
Linus Torvalds's avatar
Linus Torvalds committed
559
560
561
562
}

#else

563
564
#define obj_offset(x)			0
#define obj_size(cachep)		(cachep->buffer_size)
565
566
#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
567
568
569
570
571
572
573
574
575
576
577
#define dbg_userword(cachep, objp)	({BUG(); (void **)NULL;})

#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;

Andrew Morton's avatar
Andrew Morton committed
578
579
580
581
/*
 * 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
582
 */
583
584
585
586
587
588
589
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)
{
590
	page = compound_head(page);
591
	BUG_ON(!PageSlab(page));
592
593
594
595
596
597
598
599
600
601
	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)
{
602
	BUG_ON(!PageSlab(page));
603
604
	return (struct slab *)page->lru.prev;
}
Linus Torvalds's avatar
Linus Torvalds committed
605

606
607
static inline struct kmem_cache *virt_to_cache(const void *obj)
{
608
	struct page *page = virt_to_head_page(obj);
609
610
611
612
613
	return page_get_cache(page);
}

static inline struct slab *virt_to_slab(const void *obj)
{
614
	struct page *page = virt_to_head_page(obj);
615
616
617
	return page_get_slab(page);
}

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;
}

624
625
626
627
628
629
630
631
/*
 * 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)
632
{
633
634
	u32 offset = (obj - slab->s_mem);
	return reciprocal_divide(offset, cache->reciprocal_buffer_size);
635
636
}

Andrew Morton's avatar
Andrew Morton committed
637
638
639
/*
 * These are the default caches for kmalloc. Custom caches can have other sizes.
 */
Linus Torvalds's avatar
Linus Torvalds committed
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
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>
657
	{NULL,}
Linus Torvalds's avatar
Linus Torvalds committed
658
659
660
661
#undef CACHE
};

static struct arraycache_init initarray_cache __initdata =
662
    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
Linus Torvalds's avatar
Linus Torvalds committed
663
static struct arraycache_init initarray_generic =
664
    { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
Linus Torvalds's avatar
Linus Torvalds committed
665
666

/* internal cache of cache description objs */
667
static struct kmem_cache cache_cache = {
668
669
670
	.batchcount = 1,
	.limit = BOOT_CPUCACHE_ENTRIES,
	.shared = 1,
671
	.buffer_size = sizeof(struct kmem_cache),
672
	.name = "kmem_cache",
Linus Torvalds's avatar
Linus Torvalds committed
673
674
};

675
676
#define BAD_ALIEN_MAGIC 0x01020304ul

677
678
679
680
681
682
683
684
#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.
685
686
687
688
 *
 * 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
689
 */
690
691
692
693
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)
694
695
696

{
	int q;
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
	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++;
724
725
726
	}
}
#else
727
static inline void init_lock_keys(void)
728
729
730
731
{
}
#endif

732
/*
733
 * Guard access to the cache-chain.
734
 */
Ingo Molnar's avatar
Ingo Molnar committed
735
static DEFINE_MUTEX(cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
736
737
738
739
740
741
742
743
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,
744
745
	PARTIAL_AC,
	PARTIAL_L3,
Linus Torvalds's avatar
Linus Torvalds committed
746
747
748
	FULL
} g_cpucache_up;

749
750
751
752
753
754
755
756
/*
 * used by boot code to determine if it can use slab based allocator
 */
int slab_is_available(void)
{
	return g_cpucache_up == FULL;
}

757
static DEFINE_PER_CPU(struct delayed_work, reap_work);
Linus Torvalds's avatar
Linus Torvalds committed
758

759
static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
Linus Torvalds's avatar
Linus Torvalds committed
760
761
762
763
{
	return cachep->array[smp_processor_id()];
}

Andrew Morton's avatar
Andrew Morton committed
764
765
static inline struct kmem_cache *__find_general_cachep(size_t size,
							gfp_t gfpflags)
Linus Torvalds's avatar
Linus Torvalds committed
766
767
768
769
770
{
	struct cache_sizes *csizep = malloc_sizes;

#if DEBUG
	/* This happens if someone tries to call
771
772
773
	 * kmem_cache_create(), or __kmalloc(), before
	 * the generic caches are initialized.
	 */
774
	BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
Linus Torvalds's avatar
Linus Torvalds committed
775
#endif
776
777
778
	if (!size)
		return ZERO_SIZE_PTR;

Linus Torvalds's avatar
Linus Torvalds committed
779
780
781
782
	while (size > csizep->cs_size)
		csizep++;

	/*
783
	 * Really subtle: The last entry with cs->cs_size==ULONG_MAX
Linus Torvalds's avatar
Linus Torvalds committed
784
785
786
	 * has cs_{dma,}cachep==NULL. Thus no special case
	 * for large kmalloc calls required.
	 */
787
#ifdef CONFIG_ZONE_DMA
Linus Torvalds's avatar
Linus Torvalds committed
788
789
	if (unlikely(gfpflags & GFP_DMA))
		return csizep->cs_dmacachep;
790
#endif
Linus Torvalds's avatar
Linus Torvalds committed
791
792
793
	return csizep->cs_cachep;
}

794
static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
795
796
797
798
{
	return __find_general_cachep(size, gfpflags);
}

799
static size_t slab_mgmt_size(size_t nr_objs, size_t align)
Linus Torvalds's avatar
Linus Torvalds committed
800
{
801
802
	return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
}
Linus Torvalds's avatar
Linus Torvalds committed
803

Andrew Morton's avatar
Andrew Morton committed
804
805
806
/*
 * Calculate the number of objects and left-over bytes for a given buffer size.
 */
807
808
809
810
811
812
813
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
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
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
	/*
	 * 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
863
864
}

865
#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
Linus Torvalds's avatar
Linus Torvalds committed
866

Andrew Morton's avatar
Andrew Morton committed
867
868
static void __slab_error(const char *function, struct kmem_cache *cachep,
			char *msg)
Linus Torvalds's avatar
Linus Torvalds committed
869
870
{
	printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
871
	       function, cachep->name, msg);
Linus Torvalds's avatar
Linus Torvalds committed
872
873
874
	dump_stack();
}

875
876
877
878
879
880
881
882
883
/*
 * 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;
884
static int numa_platform __read_mostly = 1;
885
886
887
888
889
890
891
static int __init noaliencache_setup(char *s)
{
	use_alien_caches = 0;
	return 1;
}
__setup("noaliencache", noaliencache_setup);

892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
#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)
907
		node = first_node(node_online_map);
908

909
	per_cpu(reap_node, cpu) = node;
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
}

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
927
928
929
930
931
932
933
/*
 * 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.
 */
934
static void __cpuinit start_cpu_timer(int cpu)
Linus Torvalds's avatar
Linus Torvalds committed
935
{
936
	struct delayed_work *reap_work = &per_cpu(reap_work, cpu);
Linus Torvalds's avatar
Linus Torvalds committed
937
938
939
940
941
942

	/*
	 * When this gets called from do_initcalls via cpucache_init(),
	 * init_workqueues() has already run, so keventd will be setup
	 * at that time.
	 */
943
	if (keventd_up() && reap_work->work.func == NULL) {
944
		init_reap_node(cpu);
945
		INIT_DELAYED_WORK(reap_work, cache_reap);
946
947
		schedule_delayed_work_on(cpu, reap_work,
					__round_jiffies_relative(HZ, cpu));
Linus Torvalds's avatar
Linus Torvalds committed
948
949
950
	}
}

951
static struct array_cache *alloc_arraycache(int node, int entries,
952
					    int batchcount)
Linus Torvalds's avatar
Linus Torvalds committed
953
{
954
	int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
Linus Torvalds's avatar
Linus Torvalds committed
955
956
	struct array_cache *nc = NULL;

957
	nc = kmalloc_node(memsize, GFP_KERNEL, node);
Linus Torvalds's avatar
Linus Torvalds committed
958
959
960
961
962
	if (nc) {
		nc->avail = 0;
		nc->limit = entries;
		nc->batchcount = batchcount;
		nc->touched = 0;
963
		spin_lock_init(&nc->lock);
Linus Torvalds's avatar
Linus Torvalds committed
964
965
966
967
	}
	return nc;
}

968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
/*
 * 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;
}

992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
#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;
}

1017
static inline void *____cache_alloc_node(struct kmem_cache *cachep,
1018
1019
1020
1021
1022
1023
1024
		 gfp_t flags, int nodeid)
{
	return NULL;
}

#else	/* CONFIG_NUMA */

1025
static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
1026
static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
1027

Pekka Enberg's avatar
Pekka Enberg committed
1028
static struct array_cache **alloc_alien_cache(int node, int limit)
1029
1030
{
	struct array_cache **ac_ptr;
1031
	int memsize = sizeof(void *) * nr_node_ids;
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
	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]) {
1045
				for (i--; i >= 0; i--)
1046
1047
1048
1049
1050
1051
1052
1053
1054
					kfree(ac_ptr[i]);
				kfree(ac_ptr);
				return NULL;
			}
		}
	}
	return ac_ptr;
}

Pekka Enberg's avatar
Pekka Enberg committed
1055
static void free_alien_cache(struct array_cache **ac_ptr)
1056
1057
1058
1059
1060
1061
{
	int i;

	if (!ac_ptr)
		return;
	for_each_node(i)
1062
	    kfree(ac_ptr[i]);
1063
1064
1065
	kfree(ac_ptr);
}

1066
static void __drain_alien_cache(struct kmem_cache *cachep,
Pekka Enberg's avatar
Pekka Enberg committed
1067
				struct array_cache *ac, int node)
1068
1069
1070
1071
1072
{
	struct kmem_list3 *rl3 = cachep->nodelists[node];

	if (ac->avail) {
		spin_lock(&rl3->list_lock);
1073
1074
1075
1076
1077
		/*
		 * 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.
		 */
1078
1079
		if (rl3->shared)
			transfer_objects(rl3->shared, ac, ac->limit);
1080

1081
		free_block(cachep, ac->entry, ac->avail, node);
1082
1083
1084
1085
1086
		ac->avail = 0;
		spin_unlock(&rl3->list_lock);
	}
}

1087
1088
1089
1090
1091
1092
1093
1094
1095
/*
 * 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];
1096
1097

		if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
1098
1099
1100
1101
1102
1103
			__drain_alien_cache(cachep, ac, node);
			spin_unlock_irq(&ac->lock);
		}
	}
}

Andrew Morton's avatar
Andrew Morton committed
1104
1105
static void drain_alien_cache(struct kmem_cache *cachep,
				struct array_cache **alien)
1106
{
1107
	int i = 0;
1108
1109
1110
1111
	struct array_cache *ac;
	unsigned long flags;

	for_each_online_node(i) {
1112
		ac = alien[i];
1113
1114
1115
1116
1117
1118
1119
		if (ac) {
			spin_lock_irqsave(&ac->lock, flags);
			__drain_alien_cache(cachep, ac, i);
			spin_unlock_irqrestore(&ac->lock, flags);
		}
	}
}
1120

1121
static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
1122
1123
1124
1125
1126
{
	struct slab *slabp = virt_to_slab(objp);
	int nodeid = slabp->nodeid;
	struct kmem_list3 *l3;
	struct array_cache *alien = NULL;
1127
1128
1129
	int node;

	node = numa_node_id();
1130
1131
1132
1133
1134

	/*
	 * Make sure we are not freeing a object from another node to the array
	 * cache on this cpu.
	 */
1135
	if (likely(slabp->nodeid == node))
1136
1137
		return 0;

1138
	l3 = cachep->nodelists[node];
1139
1140
1141
	STATS_INC_NODEFREES(cachep);
	if (l3->alien && l3->alien[nodeid]) {
		alien = l3->alien[nodeid];
1142
		spin_lock(&alien->lock);
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
		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;
}
1156
1157
#endif

1158
1159
1160
1161
1162
static void __cpuinit cpuup_canceled(long cpu)
{
	struct kmem_cache *cachep;
	struct kmem_list3 *l3 = NULL;
	int node = cpu_to_node(cpu);
1163
	node_to_cpumask_ptr(mask, node);
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184

	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);

1185
		if (!cpus_empty(*mask)) {
1186
1187
1188
1189
1190
1191
1192
1193
1194
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
			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
1224
{
1225
	struct kmem_cache *cachep;
1226
1227
	struct kmem_list3 *l3 = NULL;
	int node = cpu_to_node(cpu);
1228
	const int memsize = sizeof(struct kmem_list3);
Linus Torvalds's avatar
Linus Torvalds committed
1229

1230
1231
1232
1233
1234
1235
1236
1237
	/*
	 * 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
1238
		/*
1239
1240
1241
		 * 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
1242
		 */
1243
1244
1245
1246
1247
1248
1249
		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;
1250

Andrew Morton's avatar
Andrew Morton committed
1251
			/*
1252
1253
1254
			 * The l3s don't come and go as CPUs come and
			 * go.  cache_chain_mutex is sufficient
			 * protection here.
1255
			 */
1256
			cachep->nodelists[node] = l3;
1257
1258
		}

1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
		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);
1283
1284
			if (!shared) {
				kfree(nc);
Linus Torvalds's avatar
Linus Torvalds committed
1285
				goto bad;
1286
			}
1287
1288
1289
		}
		if (use_alien_caches) {
			alien = alloc_alien_cache(node, cachep->limit);
1290
1291
1292
			if (!alien) {
				kfree(shared);
				kfree(nc);
1293
				goto bad;
1294
			}
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
		}
		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;
		}
1309
#ifdef CONFIG_NUMA
1310
1311
1312
		if (!l3->alien) {
			l3->alien = alien;
			alien = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
1313
		}
1314
1315
1316
1317
1318
1319
1320
#endif
		spin_unlock_irq(&l3->list_lock);
		kfree(shared);
		free_alien_cache(alien);
	}
	return 0;
bad:
1321
	cpuup_canceled(cpu);
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
	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:
1334
		mutex_lock(&cache_chain_mutex);
1335
		err = cpuup_prepare(cpu);
1336
		mutex_unlock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1337
1338
		break;
	case CPU_ONLINE:
1339
	case CPU_ONLINE_FROZEN:
Linus Torvalds's avatar
Linus Torvalds committed
1340
1341
1342
		start_cpu_timer(cpu);
		break;
#ifdef CONFIG_HOTPLUG_CPU
1343
  	case CPU_DOWN_PREPARE:
1344
  	case CPU_DOWN_PREPARE_FROZEN:
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
		/*
		 * Shutdown cache reaper. Note that the cache_chain_mutex is
		 * held so that if cache_reap() is invoked it cannot do
		 * anything expensive but will only modify reap_work
		 * and reschedule the timer.
		*/
		cancel_rearming_delayed_work(&per_cpu(reap_work, cpu));
		/* Now the cache_reaper is guaranteed to be not running. */
		per_cpu(reap_work, cpu).work.func = NULL;
  		break;
  	case CPU_DOWN_FAILED:
1356
  	case CPU_DOWN_FAILED_FROZEN:
1357
1358
		start_cpu_timer(cpu);
  		break;
Linus Torvalds's avatar
Linus Torvalds committed
1359
	case CPU_DEAD:
1360
	case CPU_DEAD_FROZEN:
1361
1362
1363
1364
1365
1366
1367
1368
		/*
		 * 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().
		 */
Simon Arlott's avatar
Simon Arlott committed
1369
		/* fall through */
1370
#endif
Linus Torvalds's avatar
Linus Torvalds committed
1371
	case CPU_UP_CANCELED:
1372
	case CPU_UP_CANCELED_FROZEN:
1373
		mutex_lock(&cache_chain_mutex);
1374
		cpuup_canceled(cpu);
Ingo Molnar's avatar
Ingo Molnar committed
1375
		mutex_unlock(&cache_chain_mutex);
Linus Torvalds's avatar
Linus Torvalds committed
1376
1377
		break;
	}
1378
	return err ? NOTIFY_BAD : NOTIFY_OK;
Linus Torvalds's avatar
Linus Torvalds committed
1379
1380
}

1381
1382
1383
static struct notifier_block __cpuinitdata cpucache_notifier = {
	&cpuup_callback, NULL, 0
};
Linus Torvalds's avatar
Linus Torvalds committed
1384

1385
1386
1387
/*
 * swap the static kmem_list3 with kmalloced memory
 */
Andrew Morton's avatar
Andrew Morton committed
1388
1389
static void init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
			int nodeid)
1390
1391
1392
1393
1394
1395
1396
1397
{
	struct kmem_list3 *ptr;

	ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_KERNEL, nodeid);
	BUG_ON(!ptr);

	local_irq_disable();
	memcpy(ptr, list, sizeof(struct kmem_list3));
1398
1399
1400
1401
1402
	/*
	 * Do not assume that spinlocks can be initialized via memcpy:
	 */
	spin_lock_init(&ptr->list_lock);

1403
1404
1405
1406
1407
	MAKE_ALL_LISTS(cachep, ptr, nodeid);
	cachep->nodelists[nodeid] = ptr;
	local_irq_enable();
}