aboutsummaryrefslogtreecommitdiff
path: root/mm/slab.h
blob: 6d7c6a5056baac906432f3b65daf6f7297aedc99 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef MM_SLAB_H
#define MM_SLAB_H
/*
 * Internal slab definitions
 */

#ifdef CONFIG_SLOB
/*
 * Common fields provided in kmem_cache by all slab allocators
 * This struct is either used directly by the allocator (SLOB)
 * or the allocator must include definitions for all fields
 * provided in kmem_cache_common in their definition of kmem_cache.
 *
 * Once we can do anonymous structs (C11 standard) we could put a
 * anonymous struct definition in these allocators so that the
 * separate allocations in the kmem_cache structure of SLAB and
 * SLUB is no longer needed.
 */
struct kmem_cache {
	unsigned int object_size;/* The original size of the object */
	unsigned int size;	/* The aligned/padded/added on size  */
	unsigned int align;	/* Alignment as calculated */
	slab_flags_t flags;	/* Active flags on the slab */
	unsigned int useroffset;/* Usercopy region offset */
	unsigned int usersize;	/* Usercopy region size */
	const char *name;	/* Slab name for sysfs */
	int refcount;		/* Use counter */
	void (*ctor)(void *);	/* Called on object slot creation */
	struct list_head list;	/* List of all slab caches on the system */
};

#endif /* CONFIG_SLOB */

#ifdef CONFIG_SLAB
#include <linux/slab_def.h>
#endif

#ifdef CONFIG_SLUB
#include <linux/slub_def.h>
#endif

#include <linux/memcontrol.h>
#include <linux/fault-inject.h>
#include <linux/kasan.h>
#include <linux/kmemleak.h>
#include <linux/random.h>
#include <linux/sched/mm.h>

/*
 * State of the slab allocator.
 *
 * This is used to describe the states of the allocator during bootup.
 * Allocators use this to gradually bootstrap themselves. Most allocators
 * have the problem that the structures used for managing slab caches are
 * allocated from slab caches themselves.
 */
enum slab_state {
	DOWN,			/* No slab functionality yet */
	PARTIAL,		/* SLUB: kmem_cache_node available */
	PARTIAL_NODE,		/* SLAB: kmalloc size for node struct available */
	UP,			/* Slab caches usable but not all extras yet */
	FULL			/* Everything is working */
};

extern enum slab_state slab_state;

/* The slab cache mutex protects the management structures during changes */
extern struct mutex slab_mutex;

/* The list of all slab caches on the system */
extern struct list_head slab_caches;

/* The slab cache that manages slab cache information */
extern struct kmem_cache *kmem_cache;

/* A table of kmalloc cache names and sizes */
extern const struct kmalloc_info_struct {
	const char *name[NR_KMALLOC_TYPES];
	unsigned int size;
} kmalloc_info[];

#ifndef CONFIG_SLOB
/* Kmalloc array related functions */
void setup_kmalloc_cache_index_table(void);
void create_kmalloc_caches(slab_flags_t);

/* Find the kmalloc slab corresponding for a certain size */
struct kmem_cache *kmalloc_slab(size_t, gfp_t);
#endif

gfp_t kmalloc_fix_flags(gfp_t flags);

/* Functions provided by the slab allocators */
int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);

struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size,
			slab_flags_t flags, unsigned int useroffset,
			unsigned int usersize);
extern void create_boot_cache(struct kmem_cache *, const char *name,
			unsigned int size, slab_flags_t flags,
			unsigned int useroffset, unsigned int usersize);

int slab_unmergeable(struct kmem_cache *s);
struct kmem_cache *find_mergeable(unsigned size, unsigned align,
		slab_flags_t flags, const char *name, void (*ctor)(void *));
#ifndef CONFIG_SLOB
struct kmem_cache *
__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
		   slab_flags_t flags, void (*ctor)(void *));

slab_flags_t kmem_cache_flags(unsigned int object_size,
	slab_flags_t flags, const char *name,
	void (*ctor)(void *));
#else
static inline struct kmem_cache *
__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
		   slab_flags_t flags, void (*ctor)(void *))
{ return NULL; }

static inline slab_flags_t kmem_cache_flags(unsigned int object_size,
	slab_flags_t flags, const char *name,
	void (*ctor)(void *))
{
	return flags;
}
#endif


/* Legal flag mask for kmem_cache_create(), for various configurations */
#define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
			 SLAB_CACHE_DMA32 | SLAB_PANIC | \
			 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )

#if defined(CONFIG_DEBUG_SLAB)
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
#elif defined(CONFIG_SLUB_DEBUG)
#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
			  SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
#else
#define SLAB_DEBUG_FLAGS (0)
#endif

#if defined(CONFIG_SLAB)
#define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
			  SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
			  SLAB_ACCOUNT)
#elif defined(CONFIG_SLUB)
#define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
			  SLAB_TEMPORARY | SLAB_ACCOUNT)
#else
#define SLAB_CACHE_FLAGS (0)
#endif

/* Common flags available with current configuration */
#define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)

/* Common flags permitted for kmem_cache_create */
#define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
			      SLAB_RED_ZONE | \
			      SLAB_POISON | \
			      SLAB_STORE_USER | \
			      SLAB_TRACE | \
			      SLAB_CONSISTENCY_CHECKS | \
			      SLAB_MEM_SPREAD | \
			      SLAB_NOLEAKTRACE | \
			      SLAB_RECLAIM_ACCOUNT | \
			      SLAB_TEMPORARY | \
			      SLAB_ACCOUNT)

bool __kmem_cache_empty(struct kmem_cache *);
int __kmem_cache_shutdown(struct kmem_cache *);
void __kmem_cache_release(struct kmem_cache *);
int __kmem_cache_shrink(struct kmem_cache *);
void slab_kmem_cache_release(struct kmem_cache *);

struct seq_file;
struct file;

struct slabinfo {
	unsigned long active_objs;
	unsigned long num_objs;
	unsigned long active_slabs;
	unsigned long num_slabs;
	unsigned long shared_avail;
	unsigned int limit;
	unsigned int batchcount;
	unsigned int shared;
	unsigned int objects_per_slab;
	unsigned int cache_order;
};

void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
ssize_t slabinfo_write(struct file *file, const char __user *buffer,
		       size_t count, loff_t *ppos);

/*
 * Generic implementation of bulk operations
 * These are useful for situations in which the allocator cannot
 * perform optimizations. In that case segments of the object listed
 * may be allocated or freed using these operations.
 */
void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);

static inline int cache_vmstat_idx(struct kmem_cache *s)
{
	return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
		NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
}

#ifdef CONFIG_SLUB_DEBUG
#ifdef CONFIG_SLUB_DEBUG_ON
DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
#else
DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
#endif
extern void print_tracking(struct kmem_cache *s, void *object);
#else
static inline void print_tracking(struct kmem_cache *s, void *object)
{
}
#endif

/*
 * Returns true if any of the specified slub_debug flags is enabled for the
 * cache. Use only for flags parsed by setup_slub_debug() as it also enables
 * the static key.
 */
static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
{
#ifdef CONFIG_SLUB_DEBUG
	VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
	if (static_branch_unlikely(&slub_debug_enabled))
		return s->flags & flags;
#endif
	return false;
}

#ifdef CONFIG_MEMCG_KMEM
static inline struct obj_cgroup **page_obj_cgroups(struct page *page)
{
	/*
	 * page->mem_cgroup and page->obj_cgroups are sharing the same
	 * space. To distinguish between them in case we don't know for sure
	 * that the page is a slab page (e.g. page_cgroup_ino()), let's
	 * always set the lowest bit of obj_cgroups.
	 */
	return (struct obj_cgroup **)
		((unsigned long)page->obj_cgroups & ~0x1UL);
}

static inline bool page_has_obj_cgroups(struct page *page)
{
	return ((unsigned long)page->obj_cgroups & 0x1UL);
}

int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
				 gfp_t gfp);

static inline void memcg_free_page_obj_cgroups(struct page *page)
{
	kfree(page_obj_cgroups(page));
	page->obj_cgroups = NULL;
}

static inline size_t obj_full_size(struct kmem_cache *s)
{
	/*
	 * For each accounted object there is an extra space which is used
	 * to store obj_cgroup membership. Charge it too.
	 */
	return s->size + sizeof(struct obj_cgroup *);
}

static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
							   size_t objects,
							   gfp_t flags)
{
	struct obj_cgroup *objcg;

	objcg = get_obj_cgroup_from_current();
	if (!objcg)
		return NULL;

	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
		obj_cgroup_put(objcg);
		return NULL;
	}

	return objcg;
}

static inline void mod_objcg_state(struct obj_cgroup *objcg,
				   struct pglist_data *pgdat,
				   int idx, int nr)
{
	struct mem_cgroup *memcg;
	struct lruvec *lruvec;

	rcu_read_lock();
	memcg = obj_cgroup_memcg(objcg);
	lruvec = mem_cgroup_lruvec(memcg, pgdat);
	mod_memcg_lruvec_state(lruvec, idx, nr);
	rcu_read_unlock();
}

static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
					      struct obj_cgroup *objcg,
					      gfp_t flags, size_t size,
					      void **p)
{
	struct page *page;
	unsigned long off;
	size_t i;

	if (!objcg)
		return;

	flags &= ~__GFP_ACCOUNT;
	for (i = 0; i < size; i++) {
		if (likely(p[i])) {
			page = virt_to_head_page(p[i]);

			if (!page_has_obj_cgroups(page) &&
			    memcg_alloc_page_obj_cgroups(page, s, flags)) {
				obj_cgroup_uncharge(objcg, obj_full_size(s));
				continue;
			}

			off = obj_to_index(s, page, p[i]);
			obj_cgroup_get(objcg);
			page_obj_cgroups(page)[off] = objcg;
			mod_objcg_state(objcg, page_pgdat(page),
					cache_vmstat_idx(s), obj_full_size(s));
		} else {
			obj_cgroup_uncharge(objcg, obj_full_size(s));
		}
	}
	obj_cgroup_put(objcg);
}

static inline void memcg_slab_free_hook(struct kmem_cache *s_orig,
					void **p, int objects)
{
	struct kmem_cache *s;
	struct obj_cgroup *objcg;
	struct page *page;
	unsigned int off;
	int i;

	if (!memcg_kmem_enabled())
		return;

	for (i = 0; i < objects; i++) {
		if (unlikely(!p[i]))
			continue;

		page = virt_to_head_page(p[i]);
		if (!page_has_obj_cgroups(page))
			continue;

		if (!s_orig)
			s = page->slab_cache;
		else
			s = s_orig;

		off = obj_to_index(s, page, p[i]);
		objcg = page_obj_cgroups(page)[off];
		if (!objcg)
			continue;

		page_obj_cgroups(page)[off] = NULL;
		obj_cgroup_uncharge(objcg, obj_full_size(s));
		mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s),
				-obj_full_size(s));
		obj_cgroup_put(objcg);
	}
}

#else /* CONFIG_MEMCG_KMEM */
static inline bool page_has_obj_cgroups(struct page *page)
{
	return false;
}

static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
{
	return NULL;
}

static inline int memcg_alloc_page_obj_cgroups(struct page *page,
					       struct kmem_cache *s, gfp_t gfp)
{
	return 0;
}

static inline void memcg_free_page_obj_cgroups(struct page *page)
{
}

static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
							   size_t objects,
							   gfp_t flags)
{
	return NULL;
}

static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
					      struct obj_cgroup *objcg,
					      gfp_t flags, size_t size,
					      void **p)
{
}

static inline void memcg_slab_free_hook(struct kmem_cache *s,
					void **p, int objects)
{
}
#endif /* CONFIG_MEMCG_KMEM */

static inline struct kmem_cache *virt_to_cache(const void *obj)
{
	struct page *page;

	page = virt_to_head_page(obj);
	if (WARN_ONCE(!PageSlab(page), "%s: Object is not a Slab page!\n",
					__func__))
		return NULL;
	return page->slab_cache;
}

static __always_inline void account_slab_page(struct page *page, int order,
					      struct kmem_cache *s)
{
	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
			    PAGE_SIZE << order);
}

static __always_inline void unaccount_slab_page(struct page *page, int order,
						struct kmem_cache *s)
{
	if (memcg_kmem_enabled())
		memcg_free_page_obj_cgroups(page);

	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
			    -(PAGE_SIZE << order));
}

static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
{
	struct kmem_cache *cachep;

	if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
	    !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
		return s;

	cachep = virt_to_cache(x);
	if (WARN(cachep && cachep != s,
		  "%s: Wrong slab cache. %s but object is from %s\n",
		  __func__, s->name, cachep->name))
		print_tracking(cachep, x);
	return cachep;
}

static inline size_t slab_ksize(const struct kmem_cache *s)
{
#ifndef CONFIG_SLUB
	return s->object_size;

#else /* CONFIG_SLUB */
# ifdef CONFIG_SLUB_DEBUG
	/*
	 * Debugging requires use of the padding between object
	 * and whatever may come after it.
	 */
	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
		return s->object_size;
# endif
	if (s->flags & SLAB_KASAN)
		return s->object_size;
	/*
	 * If we have the need to store the freelist pointer
	 * back there or track user information then we can
	 * only use the space before that information.
	 */
	if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
		return s->inuse;
	/*
	 * Else we can use all the padding etc for the allocation
	 */
	return s->size;
#endif
}

static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
						     struct obj_cgroup **objcgp,
						     size_t size, gfp_t flags)
{
	flags &= gfp_allowed_mask;

	fs_reclaim_acquire(flags);
	fs_reclaim_release(flags);

	might_sleep_if(gfpflags_allow_blocking(flags));

	if (should_failslab(s, flags))
		return NULL;

	if (memcg_kmem_enabled() &&
	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
		*objcgp = memcg_slab_pre_alloc_hook(s, size, flags);

	return s;
}

static inline void slab_post_alloc_hook(struct kmem_cache *s,
					struct obj_cgroup *objcg,
					gfp_t flags, size_t size, void **p)
{
	size_t i;

	flags &= gfp_allowed_mask;
	for (i = 0; i < size; i++) {
		p[i] = kasan_slab_alloc(s, p[i], flags);
		/* As p[i] might get tagged, call kmemleak hook after KASAN. */
		kmemleak_alloc_recursive(p[i], s->object_size, 1,
					 s->flags, flags);
	}

	if (memcg_kmem_enabled())
		memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
}

#ifndef CONFIG_SLOB
/*
 * The slab lists for all objects.
 */
struct kmem_cache_node {
	spinlock_t list_lock;

#ifdef CONFIG_SLAB
	struct list_head slabs_partial;	/* partial list first, better asm code */
	struct list_head slabs_full;
	struct list_head slabs_free;
	unsigned long total_slabs;	/* length of all slab lists */
	unsigned long free_slabs;	/* length of free slab list only */
	unsigned long free_objects;
	unsigned int free_limit;
	unsigned int colour_next;	/* Per-node cache coloring */
	struct array_cache *shared;	/* shared per node */
	struct alien_cache **alien;	/* on other nodes */
	unsigned long next_reap;	/* updated without locking */
	int free_touched;		/* updated without locking */
#endif

#ifdef CONFIG_SLUB
	unsigned long nr_partial;
	struct list_head partial;
#ifdef CONFIG_SLUB_DEBUG
	atomic_long_t nr_slabs;
	atomic_long_t total_objects;
	struct list_head full;
#endif
#endif

};

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

/*
 * Iterator over all nodes. The body will be executed for each node that has
 * a kmem_cache_node structure allocated (which is true for all online nodes)
 */
#define for_each_kmem_cache_node(__s, __node, __n) \
	for (__node = 0; __node < nr_node_ids; __node++) \
		 if ((__n = get_node(__s, __node)))

#endif

void *slab_start(struct seq_file *m, loff_t *pos);
void *slab_next(struct seq_file *m, void *p, loff_t *pos);
void slab_stop(struct seq_file *m, void *p);
int memcg_slab_show(struct seq_file *m, void *p);

#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
void dump_unreclaimable_slab(void);
#else
static inline void dump_unreclaimable_slab(void)
{
}
#endif

void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);

#ifdef CONFIG_SLAB_FREELIST_RANDOM
int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
			gfp_t gfp);
void cache_random_seq_destroy(struct kmem_cache *cachep);
#else
static inline int cache_random_seq_create(struct kmem_cache *cachep,
					unsigned int count, gfp_t gfp)
{
	return 0;
}
static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
#endif /* CONFIG_SLAB_FREELIST_RANDOM */

static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
{
	if (static_branch_unlikely(&init_on_alloc)) {
		if (c->ctor)
			return false;
		if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
			return flags & __GFP_ZERO;
		return true;
	}
	return flags & __GFP_ZERO;
}

static inline bool slab_want_init_on_free(struct kmem_cache *c)
{
	if (static_branch_unlikely(&init_on_free))
		return !(c->ctor ||
			 (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
	return false;
}

#endif /* MM_SLAB_H */