xref: /openbmc/linux/mm/slab.h (revision d0e22329)
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  */
20 struct 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 
50 /*
51  * State of the slab allocator.
52  *
53  * This is used to describe the states of the allocator during bootup.
54  * Allocators use this to gradually bootstrap themselves. Most allocators
55  * have the problem that the structures used for managing slab caches are
56  * allocated from slab caches themselves.
57  */
58 enum slab_state {
59 	DOWN,			/* No slab functionality yet */
60 	PARTIAL,		/* SLUB: kmem_cache_node available */
61 	PARTIAL_NODE,		/* SLAB: kmalloc size for node struct available */
62 	UP,			/* Slab caches usable but not all extras yet */
63 	FULL			/* Everything is working */
64 };
65 
66 extern enum slab_state slab_state;
67 
68 /* The slab cache mutex protects the management structures during changes */
69 extern struct mutex slab_mutex;
70 
71 /* The list of all slab caches on the system */
72 extern struct list_head slab_caches;
73 
74 /* The slab cache that manages slab cache information */
75 extern struct kmem_cache *kmem_cache;
76 
77 /* A table of kmalloc cache names and sizes */
78 extern const struct kmalloc_info_struct {
79 	const char *name;
80 	unsigned int size;
81 } kmalloc_info[];
82 
83 #ifndef CONFIG_SLOB
84 /* Kmalloc array related functions */
85 void setup_kmalloc_cache_index_table(void);
86 void create_kmalloc_caches(slab_flags_t);
87 
88 /* Find the kmalloc slab corresponding for a certain size */
89 struct kmem_cache *kmalloc_slab(size_t, gfp_t);
90 #endif
91 
92 
93 /* Functions provided by the slab allocators */
94 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
95 
96 struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size,
97 			slab_flags_t flags, unsigned int useroffset,
98 			unsigned int usersize);
99 extern void create_boot_cache(struct kmem_cache *, const char *name,
100 			unsigned int size, slab_flags_t flags,
101 			unsigned int useroffset, unsigned int usersize);
102 
103 int slab_unmergeable(struct kmem_cache *s);
104 struct kmem_cache *find_mergeable(unsigned size, unsigned align,
105 		slab_flags_t flags, const char *name, void (*ctor)(void *));
106 #ifndef CONFIG_SLOB
107 struct kmem_cache *
108 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
109 		   slab_flags_t flags, void (*ctor)(void *));
110 
111 slab_flags_t kmem_cache_flags(unsigned int object_size,
112 	slab_flags_t flags, const char *name,
113 	void (*ctor)(void *));
114 #else
115 static inline struct kmem_cache *
116 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
117 		   slab_flags_t flags, void (*ctor)(void *))
118 { return NULL; }
119 
120 static inline slab_flags_t kmem_cache_flags(unsigned int object_size,
121 	slab_flags_t flags, const char *name,
122 	void (*ctor)(void *))
123 {
124 	return flags;
125 }
126 #endif
127 
128 
129 /* Legal flag mask for kmem_cache_create(), for various configurations */
130 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | SLAB_PANIC | \
131 			 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS )
132 
133 #if defined(CONFIG_DEBUG_SLAB)
134 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
135 #elif defined(CONFIG_SLUB_DEBUG)
136 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
137 			  SLAB_TRACE | SLAB_CONSISTENCY_CHECKS)
138 #else
139 #define SLAB_DEBUG_FLAGS (0)
140 #endif
141 
142 #if defined(CONFIG_SLAB)
143 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \
144 			  SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \
145 			  SLAB_ACCOUNT)
146 #elif defined(CONFIG_SLUB)
147 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \
148 			  SLAB_TEMPORARY | SLAB_ACCOUNT)
149 #else
150 #define SLAB_CACHE_FLAGS (0)
151 #endif
152 
153 /* Common flags available with current configuration */
154 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS)
155 
156 /* Common flags permitted for kmem_cache_create */
157 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \
158 			      SLAB_RED_ZONE | \
159 			      SLAB_POISON | \
160 			      SLAB_STORE_USER | \
161 			      SLAB_TRACE | \
162 			      SLAB_CONSISTENCY_CHECKS | \
163 			      SLAB_MEM_SPREAD | \
164 			      SLAB_NOLEAKTRACE | \
165 			      SLAB_RECLAIM_ACCOUNT | \
166 			      SLAB_TEMPORARY | \
167 			      SLAB_ACCOUNT)
168 
169 bool __kmem_cache_empty(struct kmem_cache *);
170 int __kmem_cache_shutdown(struct kmem_cache *);
171 void __kmem_cache_release(struct kmem_cache *);
172 int __kmem_cache_shrink(struct kmem_cache *);
173 void __kmemcg_cache_deactivate(struct kmem_cache *s);
174 void slab_kmem_cache_release(struct kmem_cache *);
175 
176 struct seq_file;
177 struct file;
178 
179 struct slabinfo {
180 	unsigned long active_objs;
181 	unsigned long num_objs;
182 	unsigned long active_slabs;
183 	unsigned long num_slabs;
184 	unsigned long shared_avail;
185 	unsigned int limit;
186 	unsigned int batchcount;
187 	unsigned int shared;
188 	unsigned int objects_per_slab;
189 	unsigned int cache_order;
190 };
191 
192 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
193 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
194 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
195 		       size_t count, loff_t *ppos);
196 
197 /*
198  * Generic implementation of bulk operations
199  * These are useful for situations in which the allocator cannot
200  * perform optimizations. In that case segments of the object listed
201  * may be allocated or freed using these operations.
202  */
203 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **);
204 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **);
205 
206 #ifdef CONFIG_MEMCG_KMEM
207 
208 /* List of all root caches. */
209 extern struct list_head		slab_root_caches;
210 #define root_caches_node	memcg_params.__root_caches_node
211 
212 /*
213  * Iterate over all memcg caches of the given root cache. The caller must hold
214  * slab_mutex.
215  */
216 #define for_each_memcg_cache(iter, root) \
217 	list_for_each_entry(iter, &(root)->memcg_params.children, \
218 			    memcg_params.children_node)
219 
220 static inline bool is_root_cache(struct kmem_cache *s)
221 {
222 	return !s->memcg_params.root_cache;
223 }
224 
225 static inline bool slab_equal_or_root(struct kmem_cache *s,
226 				      struct kmem_cache *p)
227 {
228 	return p == s || p == s->memcg_params.root_cache;
229 }
230 
231 /*
232  * We use suffixes to the name in memcg because we can't have caches
233  * created in the system with the same name. But when we print them
234  * locally, better refer to them with the base name
235  */
236 static inline const char *cache_name(struct kmem_cache *s)
237 {
238 	if (!is_root_cache(s))
239 		s = s->memcg_params.root_cache;
240 	return s->name;
241 }
242 
243 /*
244  * Note, we protect with RCU only the memcg_caches array, not per-memcg caches.
245  * That said the caller must assure the memcg's cache won't go away by either
246  * taking a css reference to the owner cgroup, or holding the slab_mutex.
247  */
248 static inline struct kmem_cache *
249 cache_from_memcg_idx(struct kmem_cache *s, int idx)
250 {
251 	struct kmem_cache *cachep;
252 	struct memcg_cache_array *arr;
253 
254 	rcu_read_lock();
255 	arr = rcu_dereference(s->memcg_params.memcg_caches);
256 
257 	/*
258 	 * Make sure we will access the up-to-date value. The code updating
259 	 * memcg_caches issues a write barrier to match this (see
260 	 * memcg_create_kmem_cache()).
261 	 */
262 	cachep = READ_ONCE(arr->entries[idx]);
263 	rcu_read_unlock();
264 
265 	return cachep;
266 }
267 
268 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
269 {
270 	if (is_root_cache(s))
271 		return s;
272 	return s->memcg_params.root_cache;
273 }
274 
275 static __always_inline int memcg_charge_slab(struct page *page,
276 					     gfp_t gfp, int order,
277 					     struct kmem_cache *s)
278 {
279 	if (!memcg_kmem_enabled())
280 		return 0;
281 	if (is_root_cache(s))
282 		return 0;
283 	return memcg_kmem_charge_memcg(page, gfp, order, s->memcg_params.memcg);
284 }
285 
286 static __always_inline void memcg_uncharge_slab(struct page *page, int order,
287 						struct kmem_cache *s)
288 {
289 	if (!memcg_kmem_enabled())
290 		return;
291 	memcg_kmem_uncharge(page, order);
292 }
293 
294 extern void slab_init_memcg_params(struct kmem_cache *);
295 extern void memcg_link_cache(struct kmem_cache *s);
296 extern void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s,
297 				void (*deact_fn)(struct kmem_cache *));
298 
299 #else /* CONFIG_MEMCG_KMEM */
300 
301 /* If !memcg, all caches are root. */
302 #define slab_root_caches	slab_caches
303 #define root_caches_node	list
304 
305 #define for_each_memcg_cache(iter, root) \
306 	for ((void)(iter), (void)(root); 0; )
307 
308 static inline bool is_root_cache(struct kmem_cache *s)
309 {
310 	return true;
311 }
312 
313 static inline bool slab_equal_or_root(struct kmem_cache *s,
314 				      struct kmem_cache *p)
315 {
316 	return true;
317 }
318 
319 static inline const char *cache_name(struct kmem_cache *s)
320 {
321 	return s->name;
322 }
323 
324 static inline struct kmem_cache *
325 cache_from_memcg_idx(struct kmem_cache *s, int idx)
326 {
327 	return NULL;
328 }
329 
330 static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s)
331 {
332 	return s;
333 }
334 
335 static inline int memcg_charge_slab(struct page *page, gfp_t gfp, int order,
336 				    struct kmem_cache *s)
337 {
338 	return 0;
339 }
340 
341 static inline void memcg_uncharge_slab(struct page *page, int order,
342 				       struct kmem_cache *s)
343 {
344 }
345 
346 static inline void slab_init_memcg_params(struct kmem_cache *s)
347 {
348 }
349 
350 static inline void memcg_link_cache(struct kmem_cache *s)
351 {
352 }
353 
354 #endif /* CONFIG_MEMCG_KMEM */
355 
356 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
357 {
358 	struct kmem_cache *cachep;
359 	struct page *page;
360 
361 	/*
362 	 * When kmemcg is not being used, both assignments should return the
363 	 * same value. but we don't want to pay the assignment price in that
364 	 * case. If it is not compiled in, the compiler should be smart enough
365 	 * to not do even the assignment. In that case, slab_equal_or_root
366 	 * will also be a constant.
367 	 */
368 	if (!memcg_kmem_enabled() &&
369 	    !unlikely(s->flags & SLAB_CONSISTENCY_CHECKS))
370 		return s;
371 
372 	page = virt_to_head_page(x);
373 	cachep = page->slab_cache;
374 	if (slab_equal_or_root(cachep, s))
375 		return cachep;
376 
377 	pr_err("%s: Wrong slab cache. %s but object is from %s\n",
378 	       __func__, s->name, cachep->name);
379 	WARN_ON_ONCE(1);
380 	return s;
381 }
382 
383 static inline size_t slab_ksize(const struct kmem_cache *s)
384 {
385 #ifndef CONFIG_SLUB
386 	return s->object_size;
387 
388 #else /* CONFIG_SLUB */
389 # ifdef CONFIG_SLUB_DEBUG
390 	/*
391 	 * Debugging requires use of the padding between object
392 	 * and whatever may come after it.
393 	 */
394 	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
395 		return s->object_size;
396 # endif
397 	if (s->flags & SLAB_KASAN)
398 		return s->object_size;
399 	/*
400 	 * If we have the need to store the freelist pointer
401 	 * back there or track user information then we can
402 	 * only use the space before that information.
403 	 */
404 	if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER))
405 		return s->inuse;
406 	/*
407 	 * Else we can use all the padding etc for the allocation
408 	 */
409 	return s->size;
410 #endif
411 }
412 
413 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
414 						     gfp_t flags)
415 {
416 	flags &= gfp_allowed_mask;
417 
418 	fs_reclaim_acquire(flags);
419 	fs_reclaim_release(flags);
420 
421 	might_sleep_if(gfpflags_allow_blocking(flags));
422 
423 	if (should_failslab(s, flags))
424 		return NULL;
425 
426 	if (memcg_kmem_enabled() &&
427 	    ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT)))
428 		return memcg_kmem_get_cache(s);
429 
430 	return s;
431 }
432 
433 static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
434 					size_t size, void **p)
435 {
436 	size_t i;
437 
438 	flags &= gfp_allowed_mask;
439 	for (i = 0; i < size; i++) {
440 		void *object = p[i];
441 
442 		kmemleak_alloc_recursive(object, s->object_size, 1,
443 					 s->flags, flags);
444 		p[i] = kasan_slab_alloc(s, object, flags);
445 	}
446 
447 	if (memcg_kmem_enabled())
448 		memcg_kmem_put_cache(s);
449 }
450 
451 #ifndef CONFIG_SLOB
452 /*
453  * The slab lists for all objects.
454  */
455 struct kmem_cache_node {
456 	spinlock_t list_lock;
457 
458 #ifdef CONFIG_SLAB
459 	struct list_head slabs_partial;	/* partial list first, better asm code */
460 	struct list_head slabs_full;
461 	struct list_head slabs_free;
462 	unsigned long total_slabs;	/* length of all slab lists */
463 	unsigned long free_slabs;	/* length of free slab list only */
464 	unsigned long free_objects;
465 	unsigned int free_limit;
466 	unsigned int colour_next;	/* Per-node cache coloring */
467 	struct array_cache *shared;	/* shared per node */
468 	struct alien_cache **alien;	/* on other nodes */
469 	unsigned long next_reap;	/* updated without locking */
470 	int free_touched;		/* updated without locking */
471 #endif
472 
473 #ifdef CONFIG_SLUB
474 	unsigned long nr_partial;
475 	struct list_head partial;
476 #ifdef CONFIG_SLUB_DEBUG
477 	atomic_long_t nr_slabs;
478 	atomic_long_t total_objects;
479 	struct list_head full;
480 #endif
481 #endif
482 
483 };
484 
485 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
486 {
487 	return s->node[node];
488 }
489 
490 /*
491  * Iterator over all nodes. The body will be executed for each node that has
492  * a kmem_cache_node structure allocated (which is true for all online nodes)
493  */
494 #define for_each_kmem_cache_node(__s, __node, __n) \
495 	for (__node = 0; __node < nr_node_ids; __node++) \
496 		 if ((__n = get_node(__s, __node)))
497 
498 #endif
499 
500 void *slab_start(struct seq_file *m, loff_t *pos);
501 void *slab_next(struct seq_file *m, void *p, loff_t *pos);
502 void slab_stop(struct seq_file *m, void *p);
503 void *memcg_slab_start(struct seq_file *m, loff_t *pos);
504 void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos);
505 void memcg_slab_stop(struct seq_file *m, void *p);
506 int memcg_slab_show(struct seq_file *m, void *p);
507 
508 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
509 void dump_unreclaimable_slab(void);
510 #else
511 static inline void dump_unreclaimable_slab(void)
512 {
513 }
514 #endif
515 
516 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
517 
518 #ifdef CONFIG_SLAB_FREELIST_RANDOM
519 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
520 			gfp_t gfp);
521 void cache_random_seq_destroy(struct kmem_cache *cachep);
522 #else
523 static inline int cache_random_seq_create(struct kmem_cache *cachep,
524 					unsigned int count, gfp_t gfp)
525 {
526 	return 0;
527 }
528 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { }
529 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
530 
531 #endif /* MM_SLAB_H */
532