Linux Audio

Check our new training course

Real-Time Linux with PREEMPT_RT training

Feb 18-20, 2025
Register
Loading...
v6.2
  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef MM_SLAB_H
  3#define MM_SLAB_H
  4/*
  5 * Internal slab definitions
  6 */
  7
  8/* Reuses the bits in struct page */
  9struct slab {
 10	unsigned long __page_flags;
 11
 12#if defined(CONFIG_SLAB)
 13
 14	struct kmem_cache *slab_cache;
 15	union {
 16		struct {
 17			struct list_head slab_list;
 18			void *freelist;	/* array of free object indexes */
 19			void *s_mem;	/* first object */
 20		};
 21		struct rcu_head rcu_head;
 22	};
 23	unsigned int active;
 24
 25#elif defined(CONFIG_SLUB)
 26
 27	struct kmem_cache *slab_cache;
 28	union {
 29		struct {
 30			union {
 31				struct list_head slab_list;
 32#ifdef CONFIG_SLUB_CPU_PARTIAL
 33				struct {
 34					struct slab *next;
 35					int slabs;	/* Nr of slabs left */
 36				};
 37#endif
 38			};
 39			/* Double-word boundary */
 40			void *freelist;		/* first free object */
 41			union {
 42				unsigned long counters;
 43				struct {
 44					unsigned inuse:16;
 45					unsigned objects:15;
 46					unsigned frozen:1;
 47				};
 48			};
 49		};
 50		struct rcu_head rcu_head;
 51	};
 52	unsigned int __unused;
 53
 54#elif defined(CONFIG_SLOB)
 55
 56	struct list_head slab_list;
 57	void *__unused_1;
 58	void *freelist;		/* first free block */
 59	long units;
 60	unsigned int __unused_2;
 61
 62#else
 63#error "Unexpected slab allocator configured"
 64#endif
 65
 66	atomic_t __page_refcount;
 67#ifdef CONFIG_MEMCG
 68	unsigned long memcg_data;
 69#endif
 70};
 71
 72#define SLAB_MATCH(pg, sl)						\
 73	static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl))
 74SLAB_MATCH(flags, __page_flags);
 75#ifndef CONFIG_SLOB
 76SLAB_MATCH(compound_head, slab_cache);	/* Ensure bit 0 is clear */
 77#else
 78SLAB_MATCH(compound_head, slab_list);	/* Ensure bit 0 is clear */
 79#endif
 80SLAB_MATCH(_refcount, __page_refcount);
 81#ifdef CONFIG_MEMCG
 82SLAB_MATCH(memcg_data, memcg_data);
 83#endif
 84#undef SLAB_MATCH
 85static_assert(sizeof(struct slab) <= sizeof(struct page));
 86#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && defined(CONFIG_SLUB)
 87static_assert(IS_ALIGNED(offsetof(struct slab, freelist), 2*sizeof(void *)));
 88#endif
 89
 90/**
 91 * folio_slab - Converts from folio to slab.
 92 * @folio: The folio.
 93 *
 94 * Currently struct slab is a different representation of a folio where
 95 * folio_test_slab() is true.
 96 *
 97 * Return: The slab which contains this folio.
 98 */
 99#define folio_slab(folio)	(_Generic((folio),			\
100	const struct folio *:	(const struct slab *)(folio),		\
101	struct folio *:		(struct slab *)(folio)))
102
103/**
104 * slab_folio - The folio allocated for a slab
105 * @slab: The slab.
106 *
107 * Slabs are allocated as folios that contain the individual objects and are
108 * using some fields in the first struct page of the folio - those fields are
109 * now accessed by struct slab. It is occasionally necessary to convert back to
110 * a folio in order to communicate with the rest of the mm.  Please use this
111 * helper function instead of casting yourself, as the implementation may change
112 * in the future.
113 */
114#define slab_folio(s)		(_Generic((s),				\
115	const struct slab *:	(const struct folio *)s,		\
116	struct slab *:		(struct folio *)s))
117
118/**
119 * page_slab - Converts from first struct page to slab.
120 * @p: The first (either head of compound or single) page of slab.
121 *
122 * A temporary wrapper to convert struct page to struct slab in situations where
123 * we know the page is the compound head, or single order-0 page.
124 *
125 * Long-term ideally everything would work with struct slab directly or go
126 * through folio to struct slab.
127 *
128 * Return: The slab which contains this page
129 */
130#define page_slab(p)		(_Generic((p),				\
131	const struct page *:	(const struct slab *)(p),		\
132	struct page *:		(struct slab *)(p)))
133
134/**
135 * slab_page - The first struct page allocated for a slab
136 * @slab: The slab.
137 *
138 * A convenience wrapper for converting slab to the first struct page of the
139 * underlying folio, to communicate with code not yet converted to folio or
140 * struct slab.
141 */
142#define slab_page(s) folio_page(slab_folio(s), 0)
143
144/*
145 * If network-based swap is enabled, sl*b must keep track of whether pages
146 * were allocated from pfmemalloc reserves.
147 */
148static inline bool slab_test_pfmemalloc(const struct slab *slab)
149{
150	return folio_test_active((struct folio *)slab_folio(slab));
151}
152
153static inline void slab_set_pfmemalloc(struct slab *slab)
154{
155	folio_set_active(slab_folio(slab));
156}
157
158static inline void slab_clear_pfmemalloc(struct slab *slab)
159{
160	folio_clear_active(slab_folio(slab));
161}
162
163static inline void __slab_clear_pfmemalloc(struct slab *slab)
164{
165	__folio_clear_active(slab_folio(slab));
166}
167
168static inline void *slab_address(const struct slab *slab)
169{
170	return folio_address(slab_folio(slab));
171}
172
173static inline int slab_nid(const struct slab *slab)
174{
175	return folio_nid(slab_folio(slab));
176}
177
178static inline pg_data_t *slab_pgdat(const struct slab *slab)
179{
180	return folio_pgdat(slab_folio(slab));
181}
182
183static inline struct slab *virt_to_slab(const void *addr)
184{
185	struct folio *folio = virt_to_folio(addr);
186
187	if (!folio_test_slab(folio))
188		return NULL;
189
190	return folio_slab(folio);
191}
192
193static inline int slab_order(const struct slab *slab)
194{
195	return folio_order((struct folio *)slab_folio(slab));
196}
197
198static inline size_t slab_size(const struct slab *slab)
199{
200	return PAGE_SIZE << slab_order(slab);
201}
202
203#ifdef CONFIG_SLOB
204/*
205 * Common fields provided in kmem_cache by all slab allocators
206 * This struct is either used directly by the allocator (SLOB)
207 * or the allocator must include definitions for all fields
208 * provided in kmem_cache_common in their definition of kmem_cache.
209 *
210 * Once we can do anonymous structs (C11 standard) we could put a
211 * anonymous struct definition in these allocators so that the
212 * separate allocations in the kmem_cache structure of SLAB and
213 * SLUB is no longer needed.
214 */
215struct kmem_cache {
216	unsigned int object_size;/* The original size of the object */
217	unsigned int size;	/* The aligned/padded/added on size  */
218	unsigned int align;	/* Alignment as calculated */
219	slab_flags_t flags;	/* Active flags on the slab */
 
 
220	const char *name;	/* Slab name for sysfs */
221	int refcount;		/* Use counter */
222	void (*ctor)(void *);	/* Called on object slot creation */
223	struct list_head list;	/* List of all slab caches on the system */
224};
225
226#endif /* CONFIG_SLOB */
227
228#ifdef CONFIG_SLAB
229#include <linux/slab_def.h>
230#endif
231
232#ifdef CONFIG_SLUB
233#include <linux/slub_def.h>
234#endif
235
236#include <linux/memcontrol.h>
237#include <linux/fault-inject.h>
238#include <linux/kasan.h>
239#include <linux/kmemleak.h>
240#include <linux/random.h>
241#include <linux/sched/mm.h>
242#include <linux/list_lru.h>
243
244/*
245 * State of the slab allocator.
246 *
247 * This is used to describe the states of the allocator during bootup.
248 * Allocators use this to gradually bootstrap themselves. Most allocators
249 * have the problem that the structures used for managing slab caches are
250 * allocated from slab caches themselves.
251 */
252enum slab_state {
253	DOWN,			/* No slab functionality yet */
254	PARTIAL,		/* SLUB: kmem_cache_node available */
255	PARTIAL_NODE,		/* SLAB: kmalloc size for node struct available */
256	UP,			/* Slab caches usable but not all extras yet */
257	FULL			/* Everything is working */
258};
259
260extern enum slab_state slab_state;
261
262/* The slab cache mutex protects the management structures during changes */
263extern struct mutex slab_mutex;
264
265/* The list of all slab caches on the system */
266extern struct list_head slab_caches;
267
268/* The slab cache that manages slab cache information */
269extern struct kmem_cache *kmem_cache;
270
271/* A table of kmalloc cache names and sizes */
272extern const struct kmalloc_info_struct {
273	const char *name[NR_KMALLOC_TYPES];
274	unsigned int size;
275} kmalloc_info[];
276
277#ifndef CONFIG_SLOB
278/* Kmalloc array related functions */
279void setup_kmalloc_cache_index_table(void);
280void create_kmalloc_caches(slab_flags_t);
281
282/* Find the kmalloc slab corresponding for a certain size */
283struct kmem_cache *kmalloc_slab(size_t, gfp_t);
284
285void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags,
286			      int node, size_t orig_size,
287			      unsigned long caller);
288void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller);
289#endif
290
291gfp_t kmalloc_fix_flags(gfp_t flags);
292
293/* Functions provided by the slab allocators */
294int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
295
296struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size,
297			slab_flags_t flags, unsigned int useroffset,
298			unsigned int usersize);
299extern void create_boot_cache(struct kmem_cache *, const char *name,
300			unsigned int size, slab_flags_t flags,
301			unsigned int useroffset, unsigned int usersize);
302
303int slab_unmergeable(struct kmem_cache *s);
304struct kmem_cache *find_mergeable(unsigned size, unsigned align,
305		slab_flags_t flags, const char *name, void (*ctor)(void *));
306#ifndef CONFIG_SLOB
307struct kmem_cache *
308__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
309		   slab_flags_t flags, void (*ctor)(void *));
310
311slab_flags_t kmem_cache_flags(unsigned int object_size,
312	slab_flags_t flags, const char *name);
 
313#else
314static inline struct kmem_cache *
315__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
316		   slab_flags_t flags, void (*ctor)(void *))
317{ return NULL; }
318
319static inline slab_flags_t kmem_cache_flags(unsigned int object_size,
320	slab_flags_t flags, const char *name)
 
321{
322	return flags;
323}
324#endif
325
326
327/* Legal flag mask for kmem_cache_create(), for various configurations */
328#define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
329			 SLAB_CACHE_DMA32 | SLAB_PANIC | \
330			 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
331
332#if defined(CONFIG_DEBUG_SLAB)
333#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
334#elif defined(CONFIG_SLUB_DEBUG)
335#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
336			  SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
337#else
338#define SLAB_DEBUG_FLAGS (0)
339#endif
340
341#if defined(CONFIG_SLAB)
342#define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
343			  SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
344			  SLAB_ACCOUNT)
345#elif defined(CONFIG_SLUB)
346#define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
347			  SLAB_TEMPORARY | SLAB_ACCOUNT | \
348			  SLAB_NO_USER_FLAGS | SLAB_KMALLOC)
349#else
350#define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE)
351#endif
352
353/* Common flags available with current configuration */
354#define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
355
356/* Common flags permitted for kmem_cache_create */
357#define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
358			      SLAB_RED_ZONE | \
359			      SLAB_POISON | \
360			      SLAB_STORE_USER | \
361			      SLAB_TRACE | \
362			      SLAB_CONSISTENCY_CHECKS | \
363			      SLAB_MEM_SPREAD | \
364			      SLAB_NOLEAKTRACE | \
365			      SLAB_RECLAIM_ACCOUNT | \
366			      SLAB_TEMPORARY | \
367			      SLAB_ACCOUNT | \
368			      SLAB_KMALLOC | \
369			      SLAB_NO_USER_FLAGS)
370
371bool __kmem_cache_empty(struct kmem_cache *);
372int __kmem_cache_shutdown(struct kmem_cache *);
373void __kmem_cache_release(struct kmem_cache *);
374int __kmem_cache_shrink(struct kmem_cache *);
375void slab_kmem_cache_release(struct kmem_cache *);
376
377struct seq_file;
378struct file;
379
380struct slabinfo {
381	unsigned long active_objs;
382	unsigned long num_objs;
383	unsigned long active_slabs;
384	unsigned long num_slabs;
385	unsigned long shared_avail;
386	unsigned int limit;
387	unsigned int batchcount;
388	unsigned int shared;
389	unsigned int objects_per_slab;
390	unsigned int cache_order;
391};
392
393void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
394void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
395ssize_t slabinfo_write(struct file *file, const char __user *buffer,
396		       size_t count, loff_t *ppos);
397
398static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
 
 
 
 
 
 
 
 
 
399{
400	return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
401		NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
402}
403
404#ifdef CONFIG_SLUB_DEBUG
405#ifdef CONFIG_SLUB_DEBUG_ON
406DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
407#else
408DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
409#endif
410extern void print_tracking(struct kmem_cache *s, void *object);
411long validate_slab_cache(struct kmem_cache *s);
412static inline bool __slub_debug_enabled(void)
413{
414	return static_branch_unlikely(&slub_debug_enabled);
415}
416#else
417static inline void print_tracking(struct kmem_cache *s, void *object)
418{
419}
420static inline bool __slub_debug_enabled(void)
421{
422	return false;
423}
424#endif
425
426/*
427 * Returns true if any of the specified slub_debug flags is enabled for the
428 * cache. Use only for flags parsed by setup_slub_debug() as it also enables
429 * the static key.
430 */
431static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
432{
433	if (IS_ENABLED(CONFIG_SLUB_DEBUG))
434		VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
435	if (__slub_debug_enabled())
436		return s->flags & flags;
 
437	return false;
438}
439
440#ifdef CONFIG_MEMCG_KMEM
441/*
442 * slab_objcgs - get the object cgroups vector associated with a slab
443 * @slab: a pointer to the slab struct
444 *
445 * Returns a pointer to the object cgroups vector associated with the slab,
446 * or NULL if no such vector has been associated yet.
447 */
448static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
449{
450	unsigned long memcg_data = READ_ONCE(slab->memcg_data);
451
452	VM_BUG_ON_PAGE(memcg_data && !(memcg_data & MEMCG_DATA_OBJCGS),
453							slab_page(slab));
454	VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, slab_page(slab));
 
 
 
 
455
456	return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
 
 
457}
458
459int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s,
460				 gfp_t gfp, bool new_slab);
461void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat,
462		     enum node_stat_item idx, int nr);
463
464static inline void memcg_free_slab_cgroups(struct slab *slab)
465{
466	kfree(slab_objcgs(slab));
467	slab->memcg_data = 0;
468}
469
470static inline size_t obj_full_size(struct kmem_cache *s)
471{
472	/*
473	 * For each accounted object there is an extra space which is used
474	 * to store obj_cgroup membership. Charge it too.
475	 */
476	return s->size + sizeof(struct obj_cgroup *);
477}
478
479/*
480 * Returns false if the allocation should fail.
481 */
482static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
483					     struct list_lru *lru,
484					     struct obj_cgroup **objcgp,
485					     size_t objects, gfp_t flags)
486{
487	struct obj_cgroup *objcg;
488
489	if (!memcg_kmem_enabled())
490		return true;
491
492	if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT))
493		return true;
494
495	objcg = get_obj_cgroup_from_current();
496	if (!objcg)
497		return true;
498
499	if (lru) {
500		int ret;
501		struct mem_cgroup *memcg;
502
503		memcg = get_mem_cgroup_from_objcg(objcg);
504		ret = memcg_list_lru_alloc(memcg, lru, flags);
505		css_put(&memcg->css);
506
507		if (ret)
508			goto out;
 
509	}
510
511	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s)))
512		goto out;
513
514	*objcgp = objcg;
515	return true;
516out:
517	obj_cgroup_put(objcg);
518	return false;
 
 
 
 
 
 
 
519}
520
521static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
522					      struct obj_cgroup *objcg,
523					      gfp_t flags, size_t size,
524					      void **p)
525{
526	struct slab *slab;
527	unsigned long off;
528	size_t i;
529
530	if (!memcg_kmem_enabled() || !objcg)
531		return;
532
 
533	for (i = 0; i < size; i++) {
534		if (likely(p[i])) {
535			slab = virt_to_slab(p[i]);
536
537			if (!slab_objcgs(slab) &&
538			    memcg_alloc_slab_cgroups(slab, s, flags,
539							 false)) {
540				obj_cgroup_uncharge(objcg, obj_full_size(s));
541				continue;
542			}
543
544			off = obj_to_index(s, slab, p[i]);
545			obj_cgroup_get(objcg);
546			slab_objcgs(slab)[off] = objcg;
547			mod_objcg_state(objcg, slab_pgdat(slab),
548					cache_vmstat_idx(s), obj_full_size(s));
549		} else {
550			obj_cgroup_uncharge(objcg, obj_full_size(s));
551		}
552	}
553	obj_cgroup_put(objcg);
554}
555
556static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
557					void **p, int objects)
558{
559	struct obj_cgroup **objcgs;
560	int i;
561
562	if (!memcg_kmem_enabled())
563		return;
564
565	objcgs = slab_objcgs(slab);
566	if (!objcgs)
567		return;
568
569	for (i = 0; i < objects; i++) {
570		struct obj_cgroup *objcg;
571		unsigned int off;
572
573		off = obj_to_index(s, slab, p[i]);
574		objcg = objcgs[off];
575		if (!objcg)
576			continue;
577
578		objcgs[off] = NULL;
579		obj_cgroup_uncharge(objcg, obj_full_size(s));
580		mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s),
581				-obj_full_size(s));
582		obj_cgroup_put(objcg);
583	}
584}
585
586#else /* CONFIG_MEMCG_KMEM */
587static inline struct obj_cgroup **slab_objcgs(struct slab *slab)
588{
589	return NULL;
590}
591
592static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
593{
594	return NULL;
595}
596
597static inline int memcg_alloc_slab_cgroups(struct slab *slab,
598					       struct kmem_cache *s, gfp_t gfp,
599					       bool new_slab)
600{
601	return 0;
602}
603
604static inline void memcg_free_slab_cgroups(struct slab *slab)
605{
606}
607
608static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
609					     struct list_lru *lru,
610					     struct obj_cgroup **objcgp,
611					     size_t objects, gfp_t flags)
612{
613	return true;
614}
615
616static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
617					      struct obj_cgroup *objcg,
618					      gfp_t flags, size_t size,
619					      void **p)
620{
621}
622
623static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
624					void **p, int objects)
625{
626}
627#endif /* CONFIG_MEMCG_KMEM */
628
629#ifndef CONFIG_SLOB
630static inline struct kmem_cache *virt_to_cache(const void *obj)
631{
632	struct slab *slab;
633
634	slab = virt_to_slab(obj);
635	if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n",
636					__func__))
637		return NULL;
638	return slab->slab_cache;
639}
640
641static __always_inline void account_slab(struct slab *slab, int order,
642					 struct kmem_cache *s, gfp_t gfp)
643{
644	if (memcg_kmem_enabled() && (s->flags & SLAB_ACCOUNT))
645		memcg_alloc_slab_cgroups(slab, s, gfp, true);
646
647	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
648			    PAGE_SIZE << order);
649}
650
651static __always_inline void unaccount_slab(struct slab *slab, int order,
652					   struct kmem_cache *s)
653{
654	if (memcg_kmem_enabled())
655		memcg_free_slab_cgroups(slab);
656
657	mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
658			    -(PAGE_SIZE << order));
659}
660
661static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
662{
663	struct kmem_cache *cachep;
664
665	if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
666	    !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
667		return s;
668
669	cachep = virt_to_cache(x);
670	if (WARN(cachep && cachep != s,
671		  "%s: Wrong slab cache. %s but object is from %s\n",
672		  __func__, s->name, cachep->name))
673		print_tracking(cachep, x);
674	return cachep;
675}
676
677void free_large_kmalloc(struct folio *folio, void *object);
678
679#endif /* CONFIG_SLOB */
680
681size_t __ksize(const void *objp);
682
683static inline size_t slab_ksize(const struct kmem_cache *s)
684{
685#ifndef CONFIG_SLUB
686	return s->object_size;
687
688#else /* CONFIG_SLUB */
689# ifdef CONFIG_SLUB_DEBUG
690	/*
691	 * Debugging requires use of the padding between object
692	 * and whatever may come after it.
693	 */
694	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
695		return s->object_size;
696# endif
697	if (s->flags & SLAB_KASAN)
698		return s->object_size;
699	/*
700	 * If we have the need to store the freelist pointer
701	 * back there or track user information then we can
702	 * only use the space before that information.
703	 */
704	if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
705		return s->inuse;
706	/*
707	 * Else we can use all the padding etc for the allocation
708	 */
709	return s->size;
710#endif
711}
712
713static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
714						     struct list_lru *lru,
715						     struct obj_cgroup **objcgp,
716						     size_t size, gfp_t flags)
717{
718	flags &= gfp_allowed_mask;
719
720	might_alloc(flags);
 
 
 
721
722	if (should_failslab(s, flags))
723		return NULL;
724
725	if (!memcg_slab_pre_alloc_hook(s, lru, objcgp, size, flags))
726		return NULL;
 
727
728	return s;
729}
730
731static inline void slab_post_alloc_hook(struct kmem_cache *s,
732					struct obj_cgroup *objcg, gfp_t flags,
733					size_t size, void **p, bool init,
734					unsigned int orig_size)
735{
736	unsigned int zero_size = s->object_size;
737	size_t i;
738
739	flags &= gfp_allowed_mask;
740
741	/*
742	 * For kmalloc object, the allocated memory size(object_size) is likely
743	 * larger than the requested size(orig_size). If redzone check is
744	 * enabled for the extra space, don't zero it, as it will be redzoned
745	 * soon. The redzone operation for this extra space could be seen as a
746	 * replacement of current poisoning under certain debug option, and
747	 * won't break other sanity checks.
748	 */
749	if (kmem_cache_debug_flags(s, SLAB_STORE_USER | SLAB_RED_ZONE) &&
750	    (s->flags & SLAB_KMALLOC))
751		zero_size = orig_size;
752
753	/*
754	 * As memory initialization might be integrated into KASAN,
755	 * kasan_slab_alloc and initialization memset must be
756	 * kept together to avoid discrepancies in behavior.
757	 *
758	 * As p[i] might get tagged, memset and kmemleak hook come after KASAN.
759	 */
760	for (i = 0; i < size; i++) {
761		p[i] = kasan_slab_alloc(s, p[i], flags, init);
762		if (p[i] && init && !kasan_has_integrated_init())
763			memset(p[i], 0, zero_size);
764		kmemleak_alloc_recursive(p[i], s->object_size, 1,
765					 s->flags, flags);
766		kmsan_slab_alloc(s, p[i], flags);
767	}
768
769	memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
 
770}
771
772#ifndef CONFIG_SLOB
773/*
774 * The slab lists for all objects.
775 */
776struct kmem_cache_node {
 
 
777#ifdef CONFIG_SLAB
778	raw_spinlock_t list_lock;
779	struct list_head slabs_partial;	/* partial list first, better asm code */
780	struct list_head slabs_full;
781	struct list_head slabs_free;
782	unsigned long total_slabs;	/* length of all slab lists */
783	unsigned long free_slabs;	/* length of free slab list only */
784	unsigned long free_objects;
785	unsigned int free_limit;
786	unsigned int colour_next;	/* Per-node cache coloring */
787	struct array_cache *shared;	/* shared per node */
788	struct alien_cache **alien;	/* on other nodes */
789	unsigned long next_reap;	/* updated without locking */
790	int free_touched;		/* updated without locking */
791#endif
792
793#ifdef CONFIG_SLUB
794	spinlock_t list_lock;
795	unsigned long nr_partial;
796	struct list_head partial;
797#ifdef CONFIG_SLUB_DEBUG
798	atomic_long_t nr_slabs;
799	atomic_long_t total_objects;
800	struct list_head full;
801#endif
802#endif
803
804};
805
806static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
807{
808	return s->node[node];
809}
810
811/*
812 * Iterator over all nodes. The body will be executed for each node that has
813 * a kmem_cache_node structure allocated (which is true for all online nodes)
814 */
815#define for_each_kmem_cache_node(__s, __node, __n) \
816	for (__node = 0; __node < nr_node_ids; __node++) \
817		 if ((__n = get_node(__s, __node)))
818
819#endif
820
 
 
 
 
 
821#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
822void dump_unreclaimable_slab(void);
823#else
824static inline void dump_unreclaimable_slab(void)
825{
826}
827#endif
828
829void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
830
831#ifdef CONFIG_SLAB_FREELIST_RANDOM
832int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
833			gfp_t gfp);
834void cache_random_seq_destroy(struct kmem_cache *cachep);
835#else
836static inline int cache_random_seq_create(struct kmem_cache *cachep,
837					unsigned int count, gfp_t gfp)
838{
839	return 0;
840}
841static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
842#endif /* CONFIG_SLAB_FREELIST_RANDOM */
843
844static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
845{
846	if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON,
847				&init_on_alloc)) {
848		if (c->ctor)
849			return false;
850		if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
851			return flags & __GFP_ZERO;
852		return true;
853	}
854	return flags & __GFP_ZERO;
855}
856
857static inline bool slab_want_init_on_free(struct kmem_cache *c)
858{
859	if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON,
860				&init_on_free))
861		return !(c->ctor ||
862			 (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
863	return false;
864}
865
866#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
867void debugfs_slab_release(struct kmem_cache *);
868#else
869static inline void debugfs_slab_release(struct kmem_cache *s) { }
870#endif
871
872#ifdef CONFIG_PRINTK
873#define KS_ADDRS_COUNT 16
874struct kmem_obj_info {
875	void *kp_ptr;
876	struct slab *kp_slab;
877	void *kp_objp;
878	unsigned long kp_data_offset;
879	struct kmem_cache *kp_slab_cache;
880	void *kp_ret;
881	void *kp_stack[KS_ADDRS_COUNT];
882	void *kp_free_stack[KS_ADDRS_COUNT];
883};
884void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab);
885#endif
886
887#ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR
888void __check_heap_object(const void *ptr, unsigned long n,
889			 const struct slab *slab, bool to_user);
890#else
891static inline
892void __check_heap_object(const void *ptr, unsigned long n,
893			 const struct slab *slab, bool to_user)
894{
895}
896#endif
897
898#ifdef CONFIG_SLUB_DEBUG
899void skip_orig_size_check(struct kmem_cache *s, const void *object);
900#endif
901
902#endif /* MM_SLAB_H */
v5.9
  1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef MM_SLAB_H
  3#define MM_SLAB_H
  4/*
  5 * Internal slab definitions
  6 */
  7
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  8#ifdef CONFIG_SLOB
  9/*
 10 * Common fields provided in kmem_cache by all slab allocators
 11 * This struct is either used directly by the allocator (SLOB)
 12 * or the allocator must include definitions for all fields
 13 * provided in kmem_cache_common in their definition of kmem_cache.
 14 *
 15 * Once we can do anonymous structs (C11 standard) we could put a
 16 * anonymous struct definition in these allocators so that the
 17 * separate allocations in the kmem_cache structure of SLAB and
 18 * SLUB is no longer needed.
 19 */
 20struct kmem_cache {
 21	unsigned int object_size;/* The original size of the object */
 22	unsigned int size;	/* The aligned/padded/added on size  */
 23	unsigned int align;	/* Alignment as calculated */
 24	slab_flags_t flags;	/* Active flags on the slab */
 25	unsigned int useroffset;/* Usercopy region offset */
 26	unsigned int usersize;	/* Usercopy region size */
 27	const char *name;	/* Slab name for sysfs */
 28	int refcount;		/* Use counter */
 29	void (*ctor)(void *);	/* Called on object slot creation */
 30	struct list_head list;	/* List of all slab caches on the system */
 31};
 32
 33#endif /* CONFIG_SLOB */
 34
 35#ifdef CONFIG_SLAB
 36#include <linux/slab_def.h>
 37#endif
 38
 39#ifdef CONFIG_SLUB
 40#include <linux/slub_def.h>
 41#endif
 42
 43#include <linux/memcontrol.h>
 44#include <linux/fault-inject.h>
 45#include <linux/kasan.h>
 46#include <linux/kmemleak.h>
 47#include <linux/random.h>
 48#include <linux/sched/mm.h>
 49#include <linux/kmemleak.h>
 50
 51/*
 52 * State of the slab allocator.
 53 *
 54 * This is used to describe the states of the allocator during bootup.
 55 * Allocators use this to gradually bootstrap themselves. Most allocators
 56 * have the problem that the structures used for managing slab caches are
 57 * allocated from slab caches themselves.
 58 */
 59enum slab_state {
 60	DOWN,			/* No slab functionality yet */
 61	PARTIAL,		/* SLUB: kmem_cache_node available */
 62	PARTIAL_NODE,		/* SLAB: kmalloc size for node struct available */
 63	UP,			/* Slab caches usable but not all extras yet */
 64	FULL			/* Everything is working */
 65};
 66
 67extern enum slab_state slab_state;
 68
 69/* The slab cache mutex protects the management structures during changes */
 70extern struct mutex slab_mutex;
 71
 72/* The list of all slab caches on the system */
 73extern struct list_head slab_caches;
 74
 75/* The slab cache that manages slab cache information */
 76extern struct kmem_cache *kmem_cache;
 77
 78/* A table of kmalloc cache names and sizes */
 79extern const struct kmalloc_info_struct {
 80	const char *name[NR_KMALLOC_TYPES];
 81	unsigned int size;
 82} kmalloc_info[];
 83
 84#ifndef CONFIG_SLOB
 85/* Kmalloc array related functions */
 86void setup_kmalloc_cache_index_table(void);
 87void create_kmalloc_caches(slab_flags_t);
 88
 89/* Find the kmalloc slab corresponding for a certain size */
 90struct kmem_cache *kmalloc_slab(size_t, gfp_t);
 
 
 
 
 
 91#endif
 92
 93gfp_t kmalloc_fix_flags(gfp_t flags);
 94
 95/* Functions provided by the slab allocators */
 96int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
 97
 98struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size,
 99			slab_flags_t flags, unsigned int useroffset,
100			unsigned int usersize);
101extern void create_boot_cache(struct kmem_cache *, const char *name,
102			unsigned int size, slab_flags_t flags,
103			unsigned int useroffset, unsigned int usersize);
104
105int slab_unmergeable(struct kmem_cache *s);
106struct kmem_cache *find_mergeable(unsigned size, unsigned align,
107		slab_flags_t flags, const char *name, void (*ctor)(void *));
108#ifndef CONFIG_SLOB
109struct kmem_cache *
110__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
111		   slab_flags_t flags, void (*ctor)(void *));
112
113slab_flags_t kmem_cache_flags(unsigned int object_size,
114	slab_flags_t flags, const char *name,
115	void (*ctor)(void *));
116#else
117static inline struct kmem_cache *
118__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
119		   slab_flags_t flags, void (*ctor)(void *))
120{ return NULL; }
121
122static inline slab_flags_t kmem_cache_flags(unsigned int object_size,
123	slab_flags_t flags, const char *name,
124	void (*ctor)(void *))
125{
126	return flags;
127}
128#endif
129
130
131/* Legal flag mask for kmem_cache_create(), for various configurations */
132#define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \
133			 SLAB_CACHE_DMA32 | SLAB_PANIC | \
134			 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
135
136#if defined(CONFIG_DEBUG_SLAB)
137#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
138#elif defined(CONFIG_SLUB_DEBUG)
139#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
140			  SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
141#else
142#define SLAB_DEBUG_FLAGS (0)
143#endif
144
145#if defined(CONFIG_SLAB)
146#define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
147			  SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
148			  SLAB_ACCOUNT)
149#elif defined(CONFIG_SLUB)
150#define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
151			  SLAB_TEMPORARY | SLAB_ACCOUNT)
 
152#else
153#define SLAB_CACHE_FLAGS (0)
154#endif
155
156/* Common flags available with current configuration */
157#define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
158
159/* Common flags permitted for kmem_cache_create */
160#define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
161			      SLAB_RED_ZONE | \
162			      SLAB_POISON | \
163			      SLAB_STORE_USER | \
164			      SLAB_TRACE | \
165			      SLAB_CONSISTENCY_CHECKS | \
166			      SLAB_MEM_SPREAD | \
167			      SLAB_NOLEAKTRACE | \
168			      SLAB_RECLAIM_ACCOUNT | \
169			      SLAB_TEMPORARY | \
170			      SLAB_ACCOUNT)
 
 
171
172bool __kmem_cache_empty(struct kmem_cache *);
173int __kmem_cache_shutdown(struct kmem_cache *);
174void __kmem_cache_release(struct kmem_cache *);
175int __kmem_cache_shrink(struct kmem_cache *);
176void slab_kmem_cache_release(struct kmem_cache *);
177
178struct seq_file;
179struct file;
180
181struct slabinfo {
182	unsigned long active_objs;
183	unsigned long num_objs;
184	unsigned long active_slabs;
185	unsigned long num_slabs;
186	unsigned long shared_avail;
187	unsigned int limit;
188	unsigned int batchcount;
189	unsigned int shared;
190	unsigned int objects_per_slab;
191	unsigned int cache_order;
192};
193
194void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
195void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
196ssize_t slabinfo_write(struct file *file, const char __user *buffer,
197		       size_t count, loff_t *ppos);
198
199/*
200 * Generic implementation of bulk operations
201 * These are useful for situations in which the allocator cannot
202 * perform optimizations. In that case segments of the object listed
203 * may be allocated or freed using these operations.
204 */
205void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
206int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
207
208static inline int cache_vmstat_idx(struct kmem_cache *s)
209{
210	return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
211		NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
212}
213
214#ifdef CONFIG_SLUB_DEBUG
215#ifdef CONFIG_SLUB_DEBUG_ON
216DECLARE_STATIC_KEY_TRUE(slub_debug_enabled);
217#else
218DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
219#endif
220extern void print_tracking(struct kmem_cache *s, void *object);
 
 
 
 
 
221#else
222static inline void print_tracking(struct kmem_cache *s, void *object)
223{
224}
 
 
 
 
225#endif
226
227/*
228 * Returns true if any of the specified slub_debug flags is enabled for the
229 * cache. Use only for flags parsed by setup_slub_debug() as it also enables
230 * the static key.
231 */
232static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags)
233{
234#ifdef CONFIG_SLUB_DEBUG
235	VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS));
236	if (static_branch_unlikely(&slub_debug_enabled))
237		return s->flags & flags;
238#endif
239	return false;
240}
241
242#ifdef CONFIG_MEMCG_KMEM
243static inline struct obj_cgroup **page_obj_cgroups(struct page *page)
 
 
 
 
 
 
 
244{
245	/*
246	 * page->mem_cgroup and page->obj_cgroups are sharing the same
247	 * space. To distinguish between them in case we don't know for sure
248	 * that the page is a slab page (e.g. page_cgroup_ino()), let's
249	 * always set the lowest bit of obj_cgroups.
250	 */
251	return (struct obj_cgroup **)
252		((unsigned long)page->obj_cgroups & ~0x1UL);
253}
254
255static inline bool page_has_obj_cgroups(struct page *page)
256{
257	return ((unsigned long)page->obj_cgroups & 0x1UL);
258}
259
260int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s,
261				 gfp_t gfp);
 
 
262
263static inline void memcg_free_page_obj_cgroups(struct page *page)
264{
265	kfree(page_obj_cgroups(page));
266	page->obj_cgroups = NULL;
267}
268
269static inline size_t obj_full_size(struct kmem_cache *s)
270{
271	/*
272	 * For each accounted object there is an extra space which is used
273	 * to store obj_cgroup membership. Charge it too.
274	 */
275	return s->size + sizeof(struct obj_cgroup *);
276}
277
278static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
279							   size_t objects,
280							   gfp_t flags)
 
 
 
 
281{
282	struct obj_cgroup *objcg;
283
284	if (memcg_kmem_bypass())
285		return NULL;
 
 
 
286
287	objcg = get_obj_cgroup_from_current();
288	if (!objcg)
289		return NULL;
 
 
 
 
 
 
 
 
290
291	if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) {
292		obj_cgroup_put(objcg);
293		return NULL;
294	}
295
296	return objcg;
297}
298
299static inline void mod_objcg_state(struct obj_cgroup *objcg,
300				   struct pglist_data *pgdat,
301				   int idx, int nr)
302{
303	struct mem_cgroup *memcg;
304	struct lruvec *lruvec;
305
306	rcu_read_lock();
307	memcg = obj_cgroup_memcg(objcg);
308	lruvec = mem_cgroup_lruvec(memcg, pgdat);
309	mod_memcg_lruvec_state(lruvec, idx, nr);
310	rcu_read_unlock();
311}
312
313static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
314					      struct obj_cgroup *objcg,
315					      gfp_t flags, size_t size,
316					      void **p)
317{
318	struct page *page;
319	unsigned long off;
320	size_t i;
321
322	if (!objcg)
323		return;
324
325	flags &= ~__GFP_ACCOUNT;
326	for (i = 0; i < size; i++) {
327		if (likely(p[i])) {
328			page = virt_to_head_page(p[i]);
329
330			if (!page_has_obj_cgroups(page) &&
331			    memcg_alloc_page_obj_cgroups(page, s, flags)) {
 
332				obj_cgroup_uncharge(objcg, obj_full_size(s));
333				continue;
334			}
335
336			off = obj_to_index(s, page, p[i]);
337			obj_cgroup_get(objcg);
338			page_obj_cgroups(page)[off] = objcg;
339			mod_objcg_state(objcg, page_pgdat(page),
340					cache_vmstat_idx(s), obj_full_size(s));
341		} else {
342			obj_cgroup_uncharge(objcg, obj_full_size(s));
343		}
344	}
345	obj_cgroup_put(objcg);
346}
347
348static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
349					void *p)
350{
351	struct obj_cgroup *objcg;
352	unsigned int off;
353
354	if (!memcg_kmem_enabled())
355		return;
356
357	if (!page_has_obj_cgroups(page))
 
358		return;
359
360	off = obj_to_index(s, page, p);
361	objcg = page_obj_cgroups(page)[off];
362	page_obj_cgroups(page)[off] = NULL;
363
364	if (!objcg)
365		return;
366
367	obj_cgroup_uncharge(objcg, obj_full_size(s));
368	mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s),
369			-obj_full_size(s));
370
371	obj_cgroup_put(objcg);
 
 
 
372}
373
374#else /* CONFIG_MEMCG_KMEM */
375static inline bool page_has_obj_cgroups(struct page *page)
376{
377	return false;
378}
379
380static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
381{
382	return NULL;
383}
384
385static inline int memcg_alloc_page_obj_cgroups(struct page *page,
386					       struct kmem_cache *s, gfp_t gfp)
 
387{
388	return 0;
389}
390
391static inline void memcg_free_page_obj_cgroups(struct page *page)
392{
393}
394
395static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s,
396							   size_t objects,
397							   gfp_t flags)
 
398{
399	return NULL;
400}
401
402static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
403					      struct obj_cgroup *objcg,
404					      gfp_t flags, size_t size,
405					      void **p)
406{
407}
408
409static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page,
410					void *p)
411{
412}
413#endif /* CONFIG_MEMCG_KMEM */
414
 
415static inline struct kmem_cache *virt_to_cache(const void *obj)
416{
417	struct page *page;
418
419	page = virt_to_head_page(obj);
420	if (WARN_ONCE(!PageSlab(page), "%s: Object is not a Slab page!\n",
421					__func__))
422		return NULL;
423	return page->slab_cache;
424}
425
426static __always_inline void account_slab_page(struct page *page, int order,
427					      struct kmem_cache *s)
428{
429	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
 
 
 
430			    PAGE_SIZE << order);
431}
432
433static __always_inline void unaccount_slab_page(struct page *page, int order,
434						struct kmem_cache *s)
435{
436	if (memcg_kmem_enabled())
437		memcg_free_page_obj_cgroups(page);
438
439	mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s),
440			    -(PAGE_SIZE << order));
441}
442
443static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
444{
445	struct kmem_cache *cachep;
446
447	if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
448	    !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
449		return s;
450
451	cachep = virt_to_cache(x);
452	if (WARN(cachep && cachep != s,
453		  "%s: Wrong slab cache. %s but object is from %s\n",
454		  __func__, s->name, cachep->name))
455		print_tracking(cachep, x);
456	return cachep;
457}
458
 
 
 
 
 
 
459static inline size_t slab_ksize(const struct kmem_cache *s)
460{
461#ifndef CONFIG_SLUB
462	return s->object_size;
463
464#else /* CONFIG_SLUB */
465# ifdef CONFIG_SLUB_DEBUG
466	/*
467	 * Debugging requires use of the padding between object
468	 * and whatever may come after it.
469	 */
470	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
471		return s->object_size;
472# endif
473	if (s->flags & SLAB_KASAN)
474		return s->object_size;
475	/*
476	 * If we have the need to store the freelist pointer
477	 * back there or track user information then we can
478	 * only use the space before that information.
479	 */
480	if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
481		return s->inuse;
482	/*
483	 * Else we can use all the padding etc for the allocation
484	 */
485	return s->size;
486#endif
487}
488
489static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
 
490						     struct obj_cgroup **objcgp,
491						     size_t size, gfp_t flags)
492{
493	flags &= gfp_allowed_mask;
494
495	fs_reclaim_acquire(flags);
496	fs_reclaim_release(flags);
497
498	might_sleep_if(gfpflags_allow_blocking(flags));
499
500	if (should_failslab(s, flags))
501		return NULL;
502
503	if (memcg_kmem_enabled() &&
504	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
505		*objcgp = memcg_slab_pre_alloc_hook(s, size, flags);
506
507	return s;
508}
509
510static inline void slab_post_alloc_hook(struct kmem_cache *s,
511					struct obj_cgroup *objcg,
512					gfp_t flags, size_t size, void **p)
 
513{
 
514	size_t i;
515
516	flags &= gfp_allowed_mask;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
517	for (i = 0; i < size; i++) {
518		p[i] = kasan_slab_alloc(s, p[i], flags);
519		/* As p[i] might get tagged, call kmemleak hook after KASAN. */
 
520		kmemleak_alloc_recursive(p[i], s->object_size, 1,
521					 s->flags, flags);
 
522	}
523
524	if (memcg_kmem_enabled())
525		memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
526}
527
528#ifndef CONFIG_SLOB
529/*
530 * The slab lists for all objects.
531 */
532struct kmem_cache_node {
533	spinlock_t list_lock;
534
535#ifdef CONFIG_SLAB
 
536	struct list_head slabs_partial;	/* partial list first, better asm code */
537	struct list_head slabs_full;
538	struct list_head slabs_free;
539	unsigned long total_slabs;	/* length of all slab lists */
540	unsigned long free_slabs;	/* length of free slab list only */
541	unsigned long free_objects;
542	unsigned int free_limit;
543	unsigned int colour_next;	/* Per-node cache coloring */
544	struct array_cache *shared;	/* shared per node */
545	struct alien_cache **alien;	/* on other nodes */
546	unsigned long next_reap;	/* updated without locking */
547	int free_touched;		/* updated without locking */
548#endif
549
550#ifdef CONFIG_SLUB
 
551	unsigned long nr_partial;
552	struct list_head partial;
553#ifdef CONFIG_SLUB_DEBUG
554	atomic_long_t nr_slabs;
555	atomic_long_t total_objects;
556	struct list_head full;
557#endif
558#endif
559
560};
561
562static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
563{
564	return s->node[node];
565}
566
567/*
568 * Iterator over all nodes. The body will be executed for each node that has
569 * a kmem_cache_node structure allocated (which is true for all online nodes)
570 */
571#define for_each_kmem_cache_node(__s, __node, __n) \
572	for (__node = 0; __node < nr_node_ids; __node++) \
573		 if ((__n = get_node(__s, __node)))
574
575#endif
576
577void *slab_start(struct seq_file *m, loff_t *pos);
578void *slab_next(struct seq_file *m, void *p, loff_t *pos);
579void slab_stop(struct seq_file *m, void *p);
580int memcg_slab_show(struct seq_file *m, void *p);
581
582#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
583void dump_unreclaimable_slab(void);
584#else
585static inline void dump_unreclaimable_slab(void)
586{
587}
588#endif
589
590void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
591
592#ifdef CONFIG_SLAB_FREELIST_RANDOM
593int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
594			gfp_t gfp);
595void cache_random_seq_destroy(struct kmem_cache *cachep);
596#else
597static inline int cache_random_seq_create(struct kmem_cache *cachep,
598					unsigned int count, gfp_t gfp)
599{
600	return 0;
601}
602static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
603#endif /* CONFIG_SLAB_FREELIST_RANDOM */
604
605static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c)
606{
607	if (static_branch_unlikely(&init_on_alloc)) {
 
608		if (c->ctor)
609			return false;
610		if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))
611			return flags & __GFP_ZERO;
612		return true;
613	}
614	return flags & __GFP_ZERO;
615}
616
617static inline bool slab_want_init_on_free(struct kmem_cache *c)
618{
619	if (static_branch_unlikely(&init_on_free))
 
620		return !(c->ctor ||
621			 (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)));
622	return false;
623}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
624
625#endif /* MM_SLAB_H */