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1 | // SPDX-License-Identifier: GPL-2.0 | |
2 | /* | |
3 | * Slab allocator functions that are independent of the allocator strategy | |
4 | * | |
5 | * (C) 2012 Christoph Lameter <cl@linux.com> | |
6 | */ | |
7 | #include <linux/slab.h> | |
8 | ||
9 | #include <linux/mm.h> | |
10 | #include <linux/poison.h> | |
11 | #include <linux/interrupt.h> | |
12 | #include <linux/memory.h> | |
13 | #include <linux/cache.h> | |
14 | #include <linux/compiler.h> | |
15 | #include <linux/module.h> | |
16 | #include <linux/cpu.h> | |
17 | #include <linux/uaccess.h> | |
18 | #include <linux/seq_file.h> | |
19 | #include <linux/proc_fs.h> | |
20 | #include <asm/cacheflush.h> | |
21 | #include <asm/tlbflush.h> | |
22 | #include <asm/page.h> | |
23 | #include <linux/memcontrol.h> | |
24 | ||
25 | #define CREATE_TRACE_POINTS | |
26 | #include <trace/events/kmem.h> | |
27 | ||
28 | #include "slab.h" | |
29 | ||
30 | enum slab_state slab_state; | |
31 | LIST_HEAD(slab_caches); | |
32 | DEFINE_MUTEX(slab_mutex); | |
33 | struct kmem_cache *kmem_cache; | |
34 | ||
35 | #ifdef CONFIG_HARDENED_USERCOPY | |
36 | bool usercopy_fallback __ro_after_init = | |
37 | IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK); | |
38 | module_param(usercopy_fallback, bool, 0400); | |
39 | MODULE_PARM_DESC(usercopy_fallback, | |
40 | "WARN instead of reject usercopy whitelist violations"); | |
41 | #endif | |
42 | ||
43 | static LIST_HEAD(slab_caches_to_rcu_destroy); | |
44 | static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work); | |
45 | static DECLARE_WORK(slab_caches_to_rcu_destroy_work, | |
46 | slab_caches_to_rcu_destroy_workfn); | |
47 | ||
48 | /* | |
49 | * Set of flags that will prevent slab merging | |
50 | */ | |
51 | #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ | |
52 | SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \ | |
53 | SLAB_FAILSLAB | SLAB_KASAN) | |
54 | ||
55 | #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \ | |
56 | SLAB_CACHE_DMA32 | SLAB_ACCOUNT) | |
57 | ||
58 | /* | |
59 | * Merge control. If this is set then no merging of slab caches will occur. | |
60 | */ | |
61 | static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT); | |
62 | ||
63 | static int __init setup_slab_nomerge(char *str) | |
64 | { | |
65 | slab_nomerge = true; | |
66 | return 1; | |
67 | } | |
68 | ||
69 | #ifdef CONFIG_SLUB | |
70 | __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0); | |
71 | #endif | |
72 | ||
73 | __setup("slab_nomerge", setup_slab_nomerge); | |
74 | ||
75 | /* | |
76 | * Determine the size of a slab object | |
77 | */ | |
78 | unsigned int kmem_cache_size(struct kmem_cache *s) | |
79 | { | |
80 | return s->object_size; | |
81 | } | |
82 | EXPORT_SYMBOL(kmem_cache_size); | |
83 | ||
84 | #ifdef CONFIG_DEBUG_VM | |
85 | static int kmem_cache_sanity_check(const char *name, unsigned int size) | |
86 | { | |
87 | if (!name || in_interrupt() || size < sizeof(void *) || | |
88 | size > KMALLOC_MAX_SIZE) { | |
89 | pr_err("kmem_cache_create(%s) integrity check failed\n", name); | |
90 | return -EINVAL; | |
91 | } | |
92 | ||
93 | WARN_ON(strchr(name, ' ')); /* It confuses parsers */ | |
94 | return 0; | |
95 | } | |
96 | #else | |
97 | static inline int kmem_cache_sanity_check(const char *name, unsigned int size) | |
98 | { | |
99 | return 0; | |
100 | } | |
101 | #endif | |
102 | ||
103 | void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p) | |
104 | { | |
105 | size_t i; | |
106 | ||
107 | for (i = 0; i < nr; i++) { | |
108 | if (s) | |
109 | kmem_cache_free(s, p[i]); | |
110 | else | |
111 | kfree(p[i]); | |
112 | } | |
113 | } | |
114 | ||
115 | int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr, | |
116 | void **p) | |
117 | { | |
118 | size_t i; | |
119 | ||
120 | for (i = 0; i < nr; i++) { | |
121 | void *x = p[i] = kmem_cache_alloc(s, flags); | |
122 | if (!x) { | |
123 | __kmem_cache_free_bulk(s, i, p); | |
124 | return 0; | |
125 | } | |
126 | } | |
127 | return i; | |
128 | } | |
129 | ||
130 | #ifdef CONFIG_MEMCG_KMEM | |
131 | ||
132 | LIST_HEAD(slab_root_caches); | |
133 | ||
134 | void slab_init_memcg_params(struct kmem_cache *s) | |
135 | { | |
136 | s->memcg_params.root_cache = NULL; | |
137 | RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL); | |
138 | INIT_LIST_HEAD(&s->memcg_params.children); | |
139 | s->memcg_params.dying = false; | |
140 | } | |
141 | ||
142 | static int init_memcg_params(struct kmem_cache *s, | |
143 | struct mem_cgroup *memcg, struct kmem_cache *root_cache) | |
144 | { | |
145 | struct memcg_cache_array *arr; | |
146 | ||
147 | if (root_cache) { | |
148 | s->memcg_params.root_cache = root_cache; | |
149 | s->memcg_params.memcg = memcg; | |
150 | INIT_LIST_HEAD(&s->memcg_params.children_node); | |
151 | INIT_LIST_HEAD(&s->memcg_params.kmem_caches_node); | |
152 | return 0; | |
153 | } | |
154 | ||
155 | slab_init_memcg_params(s); | |
156 | ||
157 | if (!memcg_nr_cache_ids) | |
158 | return 0; | |
159 | ||
160 | arr = kvzalloc(sizeof(struct memcg_cache_array) + | |
161 | memcg_nr_cache_ids * sizeof(void *), | |
162 | GFP_KERNEL); | |
163 | if (!arr) | |
164 | return -ENOMEM; | |
165 | ||
166 | RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr); | |
167 | return 0; | |
168 | } | |
169 | ||
170 | static void destroy_memcg_params(struct kmem_cache *s) | |
171 | { | |
172 | if (is_root_cache(s)) | |
173 | kvfree(rcu_access_pointer(s->memcg_params.memcg_caches)); | |
174 | } | |
175 | ||
176 | static void free_memcg_params(struct rcu_head *rcu) | |
177 | { | |
178 | struct memcg_cache_array *old; | |
179 | ||
180 | old = container_of(rcu, struct memcg_cache_array, rcu); | |
181 | kvfree(old); | |
182 | } | |
183 | ||
184 | static int update_memcg_params(struct kmem_cache *s, int new_array_size) | |
185 | { | |
186 | struct memcg_cache_array *old, *new; | |
187 | ||
188 | new = kvzalloc(sizeof(struct memcg_cache_array) + | |
189 | new_array_size * sizeof(void *), GFP_KERNEL); | |
190 | if (!new) | |
191 | return -ENOMEM; | |
192 | ||
193 | old = rcu_dereference_protected(s->memcg_params.memcg_caches, | |
194 | lockdep_is_held(&slab_mutex)); | |
195 | if (old) | |
196 | memcpy(new->entries, old->entries, | |
197 | memcg_nr_cache_ids * sizeof(void *)); | |
198 | ||
199 | rcu_assign_pointer(s->memcg_params.memcg_caches, new); | |
200 | if (old) | |
201 | call_rcu(&old->rcu, free_memcg_params); | |
202 | return 0; | |
203 | } | |
204 | ||
205 | int memcg_update_all_caches(int num_memcgs) | |
206 | { | |
207 | struct kmem_cache *s; | |
208 | int ret = 0; | |
209 | ||
210 | mutex_lock(&slab_mutex); | |
211 | list_for_each_entry(s, &slab_root_caches, root_caches_node) { | |
212 | ret = update_memcg_params(s, num_memcgs); | |
213 | /* | |
214 | * Instead of freeing the memory, we'll just leave the caches | |
215 | * up to this point in an updated state. | |
216 | */ | |
217 | if (ret) | |
218 | break; | |
219 | } | |
220 | mutex_unlock(&slab_mutex); | |
221 | return ret; | |
222 | } | |
223 | ||
224 | void memcg_link_cache(struct kmem_cache *s) | |
225 | { | |
226 | if (is_root_cache(s)) { | |
227 | list_add(&s->root_caches_node, &slab_root_caches); | |
228 | } else { | |
229 | list_add(&s->memcg_params.children_node, | |
230 | &s->memcg_params.root_cache->memcg_params.children); | |
231 | list_add(&s->memcg_params.kmem_caches_node, | |
232 | &s->memcg_params.memcg->kmem_caches); | |
233 | } | |
234 | } | |
235 | ||
236 | static void memcg_unlink_cache(struct kmem_cache *s) | |
237 | { | |
238 | if (is_root_cache(s)) { | |
239 | list_del(&s->root_caches_node); | |
240 | } else { | |
241 | list_del(&s->memcg_params.children_node); | |
242 | list_del(&s->memcg_params.kmem_caches_node); | |
243 | } | |
244 | } | |
245 | #else | |
246 | static inline int init_memcg_params(struct kmem_cache *s, | |
247 | struct mem_cgroup *memcg, struct kmem_cache *root_cache) | |
248 | { | |
249 | return 0; | |
250 | } | |
251 | ||
252 | static inline void destroy_memcg_params(struct kmem_cache *s) | |
253 | { | |
254 | } | |
255 | ||
256 | static inline void memcg_unlink_cache(struct kmem_cache *s) | |
257 | { | |
258 | } | |
259 | #endif /* CONFIG_MEMCG_KMEM */ | |
260 | ||
261 | /* | |
262 | * Figure out what the alignment of the objects will be given a set of | |
263 | * flags, a user specified alignment and the size of the objects. | |
264 | */ | |
265 | static unsigned int calculate_alignment(slab_flags_t flags, | |
266 | unsigned int align, unsigned int size) | |
267 | { | |
268 | /* | |
269 | * If the user wants hardware cache aligned objects then follow that | |
270 | * suggestion if the object is sufficiently large. | |
271 | * | |
272 | * The hardware cache alignment cannot override the specified | |
273 | * alignment though. If that is greater then use it. | |
274 | */ | |
275 | if (flags & SLAB_HWCACHE_ALIGN) { | |
276 | unsigned int ralign; | |
277 | ||
278 | ralign = cache_line_size(); | |
279 | while (size <= ralign / 2) | |
280 | ralign /= 2; | |
281 | align = max(align, ralign); | |
282 | } | |
283 | ||
284 | if (align < ARCH_SLAB_MINALIGN) | |
285 | align = ARCH_SLAB_MINALIGN; | |
286 | ||
287 | return ALIGN(align, sizeof(void *)); | |
288 | } | |
289 | ||
290 | /* | |
291 | * Find a mergeable slab cache | |
292 | */ | |
293 | int slab_unmergeable(struct kmem_cache *s) | |
294 | { | |
295 | if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE)) | |
296 | return 1; | |
297 | ||
298 | if (!is_root_cache(s)) | |
299 | return 1; | |
300 | ||
301 | if (s->ctor) | |
302 | return 1; | |
303 | ||
304 | if (s->usersize) | |
305 | return 1; | |
306 | ||
307 | /* | |
308 | * We may have set a slab to be unmergeable during bootstrap. | |
309 | */ | |
310 | if (s->refcount < 0) | |
311 | return 1; | |
312 | ||
313 | return 0; | |
314 | } | |
315 | ||
316 | struct kmem_cache *find_mergeable(unsigned int size, unsigned int align, | |
317 | slab_flags_t flags, const char *name, void (*ctor)(void *)) | |
318 | { | |
319 | struct kmem_cache *s; | |
320 | ||
321 | if (slab_nomerge) | |
322 | return NULL; | |
323 | ||
324 | if (ctor) | |
325 | return NULL; | |
326 | ||
327 | size = ALIGN(size, sizeof(void *)); | |
328 | align = calculate_alignment(flags, align, size); | |
329 | size = ALIGN(size, align); | |
330 | flags = kmem_cache_flags(size, flags, name, NULL); | |
331 | ||
332 | if (flags & SLAB_NEVER_MERGE) | |
333 | return NULL; | |
334 | ||
335 | list_for_each_entry_reverse(s, &slab_root_caches, root_caches_node) { | |
336 | if (slab_unmergeable(s)) | |
337 | continue; | |
338 | ||
339 | if (size > s->size) | |
340 | continue; | |
341 | ||
342 | if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) | |
343 | continue; | |
344 | /* | |
345 | * Check if alignment is compatible. | |
346 | * Courtesy of Adrian Drzewiecki | |
347 | */ | |
348 | if ((s->size & ~(align - 1)) != s->size) | |
349 | continue; | |
350 | ||
351 | if (s->size - size >= sizeof(void *)) | |
352 | continue; | |
353 | ||
354 | if (IS_ENABLED(CONFIG_SLAB) && align && | |
355 | (align > s->align || s->align % align)) | |
356 | continue; | |
357 | ||
358 | return s; | |
359 | } | |
360 | return NULL; | |
361 | } | |
362 | ||
363 | static struct kmem_cache *create_cache(const char *name, | |
364 | unsigned int object_size, unsigned int align, | |
365 | slab_flags_t flags, unsigned int useroffset, | |
366 | unsigned int usersize, void (*ctor)(void *), | |
367 | struct mem_cgroup *memcg, struct kmem_cache *root_cache) | |
368 | { | |
369 | struct kmem_cache *s; | |
370 | int err; | |
371 | ||
372 | if (WARN_ON(useroffset + usersize > object_size)) | |
373 | useroffset = usersize = 0; | |
374 | ||
375 | err = -ENOMEM; | |
376 | s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); | |
377 | if (!s) | |
378 | goto out; | |
379 | ||
380 | s->name = name; | |
381 | s->size = s->object_size = object_size; | |
382 | s->align = align; | |
383 | s->ctor = ctor; | |
384 | s->useroffset = useroffset; | |
385 | s->usersize = usersize; | |
386 | ||
387 | err = init_memcg_params(s, memcg, root_cache); | |
388 | if (err) | |
389 | goto out_free_cache; | |
390 | ||
391 | err = __kmem_cache_create(s, flags); | |
392 | if (err) | |
393 | goto out_free_cache; | |
394 | ||
395 | s->refcount = 1; | |
396 | list_add(&s->list, &slab_caches); | |
397 | memcg_link_cache(s); | |
398 | out: | |
399 | if (err) | |
400 | return ERR_PTR(err); | |
401 | return s; | |
402 | ||
403 | out_free_cache: | |
404 | destroy_memcg_params(s); | |
405 | kmem_cache_free(kmem_cache, s); | |
406 | goto out; | |
407 | } | |
408 | ||
409 | /** | |
410 | * kmem_cache_create_usercopy - Create a cache with a region suitable | |
411 | * for copying to userspace | |
412 | * @name: A string which is used in /proc/slabinfo to identify this cache. | |
413 | * @size: The size of objects to be created in this cache. | |
414 | * @align: The required alignment for the objects. | |
415 | * @flags: SLAB flags | |
416 | * @useroffset: Usercopy region offset | |
417 | * @usersize: Usercopy region size | |
418 | * @ctor: A constructor for the objects. | |
419 | * | |
420 | * Cannot be called within a interrupt, but can be interrupted. | |
421 | * The @ctor is run when new pages are allocated by the cache. | |
422 | * | |
423 | * The flags are | |
424 | * | |
425 | * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) | |
426 | * to catch references to uninitialised memory. | |
427 | * | |
428 | * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check | |
429 | * for buffer overruns. | |
430 | * | |
431 | * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware | |
432 | * cacheline. This can be beneficial if you're counting cycles as closely | |
433 | * as davem. | |
434 | * | |
435 | * Return: a pointer to the cache on success, NULL on failure. | |
436 | */ | |
437 | struct kmem_cache * | |
438 | kmem_cache_create_usercopy(const char *name, | |
439 | unsigned int size, unsigned int align, | |
440 | slab_flags_t flags, | |
441 | unsigned int useroffset, unsigned int usersize, | |
442 | void (*ctor)(void *)) | |
443 | { | |
444 | struct kmem_cache *s = NULL; | |
445 | const char *cache_name; | |
446 | int err; | |
447 | ||
448 | get_online_cpus(); | |
449 | get_online_mems(); | |
450 | memcg_get_cache_ids(); | |
451 | ||
452 | mutex_lock(&slab_mutex); | |
453 | ||
454 | err = kmem_cache_sanity_check(name, size); | |
455 | if (err) { | |
456 | goto out_unlock; | |
457 | } | |
458 | ||
459 | /* Refuse requests with allocator specific flags */ | |
460 | if (flags & ~SLAB_FLAGS_PERMITTED) { | |
461 | err = -EINVAL; | |
462 | goto out_unlock; | |
463 | } | |
464 | ||
465 | /* | |
466 | * Some allocators will constraint the set of valid flags to a subset | |
467 | * of all flags. We expect them to define CACHE_CREATE_MASK in this | |
468 | * case, and we'll just provide them with a sanitized version of the | |
469 | * passed flags. | |
470 | */ | |
471 | flags &= CACHE_CREATE_MASK; | |
472 | ||
473 | /* Fail closed on bad usersize of useroffset values. */ | |
474 | if (WARN_ON(!usersize && useroffset) || | |
475 | WARN_ON(size < usersize || size - usersize < useroffset)) | |
476 | usersize = useroffset = 0; | |
477 | ||
478 | if (!usersize) | |
479 | s = __kmem_cache_alias(name, size, align, flags, ctor); | |
480 | if (s) | |
481 | goto out_unlock; | |
482 | ||
483 | cache_name = kstrdup_const(name, GFP_KERNEL); | |
484 | if (!cache_name) { | |
485 | err = -ENOMEM; | |
486 | goto out_unlock; | |
487 | } | |
488 | ||
489 | s = create_cache(cache_name, size, | |
490 | calculate_alignment(flags, align, size), | |
491 | flags, useroffset, usersize, ctor, NULL, NULL); | |
492 | if (IS_ERR(s)) { | |
493 | err = PTR_ERR(s); | |
494 | kfree_const(cache_name); | |
495 | } | |
496 | ||
497 | out_unlock: | |
498 | mutex_unlock(&slab_mutex); | |
499 | ||
500 | memcg_put_cache_ids(); | |
501 | put_online_mems(); | |
502 | put_online_cpus(); | |
503 | ||
504 | if (err) { | |
505 | if (flags & SLAB_PANIC) | |
506 | panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", | |
507 | name, err); | |
508 | else { | |
509 | pr_warn("kmem_cache_create(%s) failed with error %d\n", | |
510 | name, err); | |
511 | dump_stack(); | |
512 | } | |
513 | return NULL; | |
514 | } | |
515 | return s; | |
516 | } | |
517 | EXPORT_SYMBOL(kmem_cache_create_usercopy); | |
518 | ||
519 | /** | |
520 | * kmem_cache_create - Create a cache. | |
521 | * @name: A string which is used in /proc/slabinfo to identify this cache. | |
522 | * @size: The size of objects to be created in this cache. | |
523 | * @align: The required alignment for the objects. | |
524 | * @flags: SLAB flags | |
525 | * @ctor: A constructor for the objects. | |
526 | * | |
527 | * Cannot be called within a interrupt, but can be interrupted. | |
528 | * The @ctor is run when new pages are allocated by the cache. | |
529 | * | |
530 | * The flags are | |
531 | * | |
532 | * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) | |
533 | * to catch references to uninitialised memory. | |
534 | * | |
535 | * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check | |
536 | * for buffer overruns. | |
537 | * | |
538 | * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware | |
539 | * cacheline. This can be beneficial if you're counting cycles as closely | |
540 | * as davem. | |
541 | * | |
542 | * Return: a pointer to the cache on success, NULL on failure. | |
543 | */ | |
544 | struct kmem_cache * | |
545 | kmem_cache_create(const char *name, unsigned int size, unsigned int align, | |
546 | slab_flags_t flags, void (*ctor)(void *)) | |
547 | { | |
548 | return kmem_cache_create_usercopy(name, size, align, flags, 0, 0, | |
549 | ctor); | |
550 | } | |
551 | EXPORT_SYMBOL(kmem_cache_create); | |
552 | ||
553 | static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) | |
554 | { | |
555 | LIST_HEAD(to_destroy); | |
556 | struct kmem_cache *s, *s2; | |
557 | ||
558 | /* | |
559 | * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the | |
560 | * @slab_caches_to_rcu_destroy list. The slab pages are freed | |
561 | * through RCU and and the associated kmem_cache are dereferenced | |
562 | * while freeing the pages, so the kmem_caches should be freed only | |
563 | * after the pending RCU operations are finished. As rcu_barrier() | |
564 | * is a pretty slow operation, we batch all pending destructions | |
565 | * asynchronously. | |
566 | */ | |
567 | mutex_lock(&slab_mutex); | |
568 | list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy); | |
569 | mutex_unlock(&slab_mutex); | |
570 | ||
571 | if (list_empty(&to_destroy)) | |
572 | return; | |
573 | ||
574 | rcu_barrier(); | |
575 | ||
576 | list_for_each_entry_safe(s, s2, &to_destroy, list) { | |
577 | #ifdef SLAB_SUPPORTS_SYSFS | |
578 | sysfs_slab_release(s); | |
579 | #else | |
580 | slab_kmem_cache_release(s); | |
581 | #endif | |
582 | } | |
583 | } | |
584 | ||
585 | static int shutdown_cache(struct kmem_cache *s) | |
586 | { | |
587 | /* free asan quarantined objects */ | |
588 | kasan_cache_shutdown(s); | |
589 | ||
590 | if (__kmem_cache_shutdown(s) != 0) | |
591 | return -EBUSY; | |
592 | ||
593 | memcg_unlink_cache(s); | |
594 | list_del(&s->list); | |
595 | ||
596 | if (s->flags & SLAB_TYPESAFE_BY_RCU) { | |
597 | #ifdef SLAB_SUPPORTS_SYSFS | |
598 | sysfs_slab_unlink(s); | |
599 | #endif | |
600 | list_add_tail(&s->list, &slab_caches_to_rcu_destroy); | |
601 | schedule_work(&slab_caches_to_rcu_destroy_work); | |
602 | } else { | |
603 | #ifdef SLAB_SUPPORTS_SYSFS | |
604 | sysfs_slab_unlink(s); | |
605 | sysfs_slab_release(s); | |
606 | #else | |
607 | slab_kmem_cache_release(s); | |
608 | #endif | |
609 | } | |
610 | ||
611 | return 0; | |
612 | } | |
613 | ||
614 | #ifdef CONFIG_MEMCG_KMEM | |
615 | /* | |
616 | * memcg_create_kmem_cache - Create a cache for a memory cgroup. | |
617 | * @memcg: The memory cgroup the new cache is for. | |
618 | * @root_cache: The parent of the new cache. | |
619 | * | |
620 | * This function attempts to create a kmem cache that will serve allocation | |
621 | * requests going from @memcg to @root_cache. The new cache inherits properties | |
622 | * from its parent. | |
623 | */ | |
624 | void memcg_create_kmem_cache(struct mem_cgroup *memcg, | |
625 | struct kmem_cache *root_cache) | |
626 | { | |
627 | static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */ | |
628 | struct cgroup_subsys_state *css = &memcg->css; | |
629 | struct memcg_cache_array *arr; | |
630 | struct kmem_cache *s = NULL; | |
631 | char *cache_name; | |
632 | int idx; | |
633 | ||
634 | get_online_cpus(); | |
635 | get_online_mems(); | |
636 | ||
637 | mutex_lock(&slab_mutex); | |
638 | ||
639 | /* | |
640 | * The memory cgroup could have been offlined while the cache | |
641 | * creation work was pending. | |
642 | */ | |
643 | if (memcg->kmem_state != KMEM_ONLINE || root_cache->memcg_params.dying) | |
644 | goto out_unlock; | |
645 | ||
646 | idx = memcg_cache_id(memcg); | |
647 | arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches, | |
648 | lockdep_is_held(&slab_mutex)); | |
649 | ||
650 | /* | |
651 | * Since per-memcg caches are created asynchronously on first | |
652 | * allocation (see memcg_kmem_get_cache()), several threads can try to | |
653 | * create the same cache, but only one of them may succeed. | |
654 | */ | |
655 | if (arr->entries[idx]) | |
656 | goto out_unlock; | |
657 | ||
658 | cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf)); | |
659 | cache_name = kasprintf(GFP_KERNEL, "%s(%llu:%s)", root_cache->name, | |
660 | css->serial_nr, memcg_name_buf); | |
661 | if (!cache_name) | |
662 | goto out_unlock; | |
663 | ||
664 | s = create_cache(cache_name, root_cache->object_size, | |
665 | root_cache->align, | |
666 | root_cache->flags & CACHE_CREATE_MASK, | |
667 | root_cache->useroffset, root_cache->usersize, | |
668 | root_cache->ctor, memcg, root_cache); | |
669 | /* | |
670 | * If we could not create a memcg cache, do not complain, because | |
671 | * that's not critical at all as we can always proceed with the root | |
672 | * cache. | |
673 | */ | |
674 | if (IS_ERR(s)) { | |
675 | kfree(cache_name); | |
676 | goto out_unlock; | |
677 | } | |
678 | ||
679 | /* | |
680 | * Since readers won't lock (see cache_from_memcg_idx()), we need a | |
681 | * barrier here to ensure nobody will see the kmem_cache partially | |
682 | * initialized. | |
683 | */ | |
684 | smp_wmb(); | |
685 | arr->entries[idx] = s; | |
686 | ||
687 | out_unlock: | |
688 | mutex_unlock(&slab_mutex); | |
689 | ||
690 | put_online_mems(); | |
691 | put_online_cpus(); | |
692 | } | |
693 | ||
694 | static void kmemcg_deactivate_workfn(struct work_struct *work) | |
695 | { | |
696 | struct kmem_cache *s = container_of(work, struct kmem_cache, | |
697 | memcg_params.deact_work); | |
698 | ||
699 | get_online_cpus(); | |
700 | get_online_mems(); | |
701 | ||
702 | mutex_lock(&slab_mutex); | |
703 | ||
704 | s->memcg_params.deact_fn(s); | |
705 | ||
706 | mutex_unlock(&slab_mutex); | |
707 | ||
708 | put_online_mems(); | |
709 | put_online_cpus(); | |
710 | ||
711 | /* done, put the ref from slab_deactivate_memcg_cache_rcu_sched() */ | |
712 | css_put(&s->memcg_params.memcg->css); | |
713 | } | |
714 | ||
715 | static void kmemcg_deactivate_rcufn(struct rcu_head *head) | |
716 | { | |
717 | struct kmem_cache *s = container_of(head, struct kmem_cache, | |
718 | memcg_params.deact_rcu_head); | |
719 | ||
720 | /* | |
721 | * We need to grab blocking locks. Bounce to ->deact_work. The | |
722 | * work item shares the space with the RCU head and can't be | |
723 | * initialized eariler. | |
724 | */ | |
725 | INIT_WORK(&s->memcg_params.deact_work, kmemcg_deactivate_workfn); | |
726 | queue_work(memcg_kmem_cache_wq, &s->memcg_params.deact_work); | |
727 | } | |
728 | ||
729 | /** | |
730 | * slab_deactivate_memcg_cache_rcu_sched - schedule deactivation after a | |
731 | * sched RCU grace period | |
732 | * @s: target kmem_cache | |
733 | * @deact_fn: deactivation function to call | |
734 | * | |
735 | * Schedule @deact_fn to be invoked with online cpus, mems and slab_mutex | |
736 | * held after a sched RCU grace period. The slab is guaranteed to stay | |
737 | * alive until @deact_fn is finished. This is to be used from | |
738 | * __kmemcg_cache_deactivate(). | |
739 | */ | |
740 | void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s, | |
741 | void (*deact_fn)(struct kmem_cache *)) | |
742 | { | |
743 | if (WARN_ON_ONCE(is_root_cache(s)) || | |
744 | WARN_ON_ONCE(s->memcg_params.deact_fn)) | |
745 | return; | |
746 | ||
747 | if (s->memcg_params.root_cache->memcg_params.dying) | |
748 | return; | |
749 | ||
750 | /* pin memcg so that @s doesn't get destroyed in the middle */ | |
751 | css_get(&s->memcg_params.memcg->css); | |
752 | ||
753 | s->memcg_params.deact_fn = deact_fn; | |
754 | call_rcu(&s->memcg_params.deact_rcu_head, kmemcg_deactivate_rcufn); | |
755 | } | |
756 | ||
757 | void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) | |
758 | { | |
759 | int idx; | |
760 | struct memcg_cache_array *arr; | |
761 | struct kmem_cache *s, *c; | |
762 | ||
763 | idx = memcg_cache_id(memcg); | |
764 | ||
765 | get_online_cpus(); | |
766 | get_online_mems(); | |
767 | ||
768 | mutex_lock(&slab_mutex); | |
769 | list_for_each_entry(s, &slab_root_caches, root_caches_node) { | |
770 | arr = rcu_dereference_protected(s->memcg_params.memcg_caches, | |
771 | lockdep_is_held(&slab_mutex)); | |
772 | c = arr->entries[idx]; | |
773 | if (!c) | |
774 | continue; | |
775 | ||
776 | __kmemcg_cache_deactivate(c); | |
777 | arr->entries[idx] = NULL; | |
778 | } | |
779 | mutex_unlock(&slab_mutex); | |
780 | ||
781 | put_online_mems(); | |
782 | put_online_cpus(); | |
783 | } | |
784 | ||
785 | void memcg_destroy_kmem_caches(struct mem_cgroup *memcg) | |
786 | { | |
787 | struct kmem_cache *s, *s2; | |
788 | ||
789 | get_online_cpus(); | |
790 | get_online_mems(); | |
791 | ||
792 | mutex_lock(&slab_mutex); | |
793 | list_for_each_entry_safe(s, s2, &memcg->kmem_caches, | |
794 | memcg_params.kmem_caches_node) { | |
795 | /* | |
796 | * The cgroup is about to be freed and therefore has no charges | |
797 | * left. Hence, all its caches must be empty by now. | |
798 | */ | |
799 | BUG_ON(shutdown_cache(s)); | |
800 | } | |
801 | mutex_unlock(&slab_mutex); | |
802 | ||
803 | put_online_mems(); | |
804 | put_online_cpus(); | |
805 | } | |
806 | ||
807 | static int shutdown_memcg_caches(struct kmem_cache *s) | |
808 | { | |
809 | struct memcg_cache_array *arr; | |
810 | struct kmem_cache *c, *c2; | |
811 | LIST_HEAD(busy); | |
812 | int i; | |
813 | ||
814 | BUG_ON(!is_root_cache(s)); | |
815 | ||
816 | /* | |
817 | * First, shutdown active caches, i.e. caches that belong to online | |
818 | * memory cgroups. | |
819 | */ | |
820 | arr = rcu_dereference_protected(s->memcg_params.memcg_caches, | |
821 | lockdep_is_held(&slab_mutex)); | |
822 | for_each_memcg_cache_index(i) { | |
823 | c = arr->entries[i]; | |
824 | if (!c) | |
825 | continue; | |
826 | if (shutdown_cache(c)) | |
827 | /* | |
828 | * The cache still has objects. Move it to a temporary | |
829 | * list so as not to try to destroy it for a second | |
830 | * time while iterating over inactive caches below. | |
831 | */ | |
832 | list_move(&c->memcg_params.children_node, &busy); | |
833 | else | |
834 | /* | |
835 | * The cache is empty and will be destroyed soon. Clear | |
836 | * the pointer to it in the memcg_caches array so that | |
837 | * it will never be accessed even if the root cache | |
838 | * stays alive. | |
839 | */ | |
840 | arr->entries[i] = NULL; | |
841 | } | |
842 | ||
843 | /* | |
844 | * Second, shutdown all caches left from memory cgroups that are now | |
845 | * offline. | |
846 | */ | |
847 | list_for_each_entry_safe(c, c2, &s->memcg_params.children, | |
848 | memcg_params.children_node) | |
849 | shutdown_cache(c); | |
850 | ||
851 | list_splice(&busy, &s->memcg_params.children); | |
852 | ||
853 | /* | |
854 | * A cache being destroyed must be empty. In particular, this means | |
855 | * that all per memcg caches attached to it must be empty too. | |
856 | */ | |
857 | if (!list_empty(&s->memcg_params.children)) | |
858 | return -EBUSY; | |
859 | return 0; | |
860 | } | |
861 | ||
862 | static void flush_memcg_workqueue(struct kmem_cache *s) | |
863 | { | |
864 | mutex_lock(&slab_mutex); | |
865 | s->memcg_params.dying = true; | |
866 | mutex_unlock(&slab_mutex); | |
867 | ||
868 | /* | |
869 | * SLUB deactivates the kmem_caches through call_rcu. Make | |
870 | * sure all registered rcu callbacks have been invoked. | |
871 | */ | |
872 | if (IS_ENABLED(CONFIG_SLUB)) | |
873 | rcu_barrier(); | |
874 | ||
875 | /* | |
876 | * SLAB and SLUB create memcg kmem_caches through workqueue and SLUB | |
877 | * deactivates the memcg kmem_caches through workqueue. Make sure all | |
878 | * previous workitems on workqueue are processed. | |
879 | */ | |
880 | flush_workqueue(memcg_kmem_cache_wq); | |
881 | } | |
882 | #else | |
883 | static inline int shutdown_memcg_caches(struct kmem_cache *s) | |
884 | { | |
885 | return 0; | |
886 | } | |
887 | ||
888 | static inline void flush_memcg_workqueue(struct kmem_cache *s) | |
889 | { | |
890 | } | |
891 | #endif /* CONFIG_MEMCG_KMEM */ | |
892 | ||
893 | void slab_kmem_cache_release(struct kmem_cache *s) | |
894 | { | |
895 | __kmem_cache_release(s); | |
896 | destroy_memcg_params(s); | |
897 | kfree_const(s->name); | |
898 | kmem_cache_free(kmem_cache, s); | |
899 | } | |
900 | ||
901 | void kmem_cache_destroy(struct kmem_cache *s) | |
902 | { | |
903 | int err; | |
904 | ||
905 | if (unlikely(!s)) | |
906 | return; | |
907 | ||
908 | flush_memcg_workqueue(s); | |
909 | ||
910 | get_online_cpus(); | |
911 | get_online_mems(); | |
912 | ||
913 | mutex_lock(&slab_mutex); | |
914 | ||
915 | s->refcount--; | |
916 | if (s->refcount) | |
917 | goto out_unlock; | |
918 | ||
919 | err = shutdown_memcg_caches(s); | |
920 | if (!err) | |
921 | err = shutdown_cache(s); | |
922 | ||
923 | if (err) { | |
924 | pr_err("kmem_cache_destroy %s: Slab cache still has objects\n", | |
925 | s->name); | |
926 | dump_stack(); | |
927 | } | |
928 | out_unlock: | |
929 | mutex_unlock(&slab_mutex); | |
930 | ||
931 | put_online_mems(); | |
932 | put_online_cpus(); | |
933 | } | |
934 | EXPORT_SYMBOL(kmem_cache_destroy); | |
935 | ||
936 | /** | |
937 | * kmem_cache_shrink - Shrink a cache. | |
938 | * @cachep: The cache to shrink. | |
939 | * | |
940 | * Releases as many slabs as possible for a cache. | |
941 | * To help debugging, a zero exit status indicates all slabs were released. | |
942 | * | |
943 | * Return: %0 if all slabs were released, non-zero otherwise | |
944 | */ | |
945 | int kmem_cache_shrink(struct kmem_cache *cachep) | |
946 | { | |
947 | int ret; | |
948 | ||
949 | get_online_cpus(); | |
950 | get_online_mems(); | |
951 | kasan_cache_shrink(cachep); | |
952 | ret = __kmem_cache_shrink(cachep); | |
953 | put_online_mems(); | |
954 | put_online_cpus(); | |
955 | return ret; | |
956 | } | |
957 | EXPORT_SYMBOL(kmem_cache_shrink); | |
958 | ||
959 | bool slab_is_available(void) | |
960 | { | |
961 | return slab_state >= UP; | |
962 | } | |
963 | ||
964 | #ifndef CONFIG_SLOB | |
965 | /* Create a cache during boot when no slab services are available yet */ | |
966 | void __init create_boot_cache(struct kmem_cache *s, const char *name, | |
967 | unsigned int size, slab_flags_t flags, | |
968 | unsigned int useroffset, unsigned int usersize) | |
969 | { | |
970 | int err; | |
971 | ||
972 | s->name = name; | |
973 | s->size = s->object_size = size; | |
974 | s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size); | |
975 | s->useroffset = useroffset; | |
976 | s->usersize = usersize; | |
977 | ||
978 | slab_init_memcg_params(s); | |
979 | ||
980 | err = __kmem_cache_create(s, flags); | |
981 | ||
982 | if (err) | |
983 | panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n", | |
984 | name, size, err); | |
985 | ||
986 | s->refcount = -1; /* Exempt from merging for now */ | |
987 | } | |
988 | ||
989 | struct kmem_cache *__init create_kmalloc_cache(const char *name, | |
990 | unsigned int size, slab_flags_t flags, | |
991 | unsigned int useroffset, unsigned int usersize) | |
992 | { | |
993 | struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); | |
994 | ||
995 | if (!s) | |
996 | panic("Out of memory when creating slab %s\n", name); | |
997 | ||
998 | create_boot_cache(s, name, size, flags, useroffset, usersize); | |
999 | list_add(&s->list, &slab_caches); | |
1000 | memcg_link_cache(s); | |
1001 | s->refcount = 1; | |
1002 | return s; | |
1003 | } | |
1004 | ||
1005 | struct kmem_cache * | |
1006 | kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init; | |
1007 | EXPORT_SYMBOL(kmalloc_caches); | |
1008 | ||
1009 | /* | |
1010 | * Conversion table for small slabs sizes / 8 to the index in the | |
1011 | * kmalloc array. This is necessary for slabs < 192 since we have non power | |
1012 | * of two cache sizes there. The size of larger slabs can be determined using | |
1013 | * fls. | |
1014 | */ | |
1015 | static u8 size_index[24] __ro_after_init = { | |
1016 | 3, /* 8 */ | |
1017 | 4, /* 16 */ | |
1018 | 5, /* 24 */ | |
1019 | 5, /* 32 */ | |
1020 | 6, /* 40 */ | |
1021 | 6, /* 48 */ | |
1022 | 6, /* 56 */ | |
1023 | 6, /* 64 */ | |
1024 | 1, /* 72 */ | |
1025 | 1, /* 80 */ | |
1026 | 1, /* 88 */ | |
1027 | 1, /* 96 */ | |
1028 | 7, /* 104 */ | |
1029 | 7, /* 112 */ | |
1030 | 7, /* 120 */ | |
1031 | 7, /* 128 */ | |
1032 | 2, /* 136 */ | |
1033 | 2, /* 144 */ | |
1034 | 2, /* 152 */ | |
1035 | 2, /* 160 */ | |
1036 | 2, /* 168 */ | |
1037 | 2, /* 176 */ | |
1038 | 2, /* 184 */ | |
1039 | 2 /* 192 */ | |
1040 | }; | |
1041 | ||
1042 | static inline unsigned int size_index_elem(unsigned int bytes) | |
1043 | { | |
1044 | return (bytes - 1) / 8; | |
1045 | } | |
1046 | ||
1047 | /* | |
1048 | * Find the kmem_cache structure that serves a given size of | |
1049 | * allocation | |
1050 | */ | |
1051 | struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) | |
1052 | { | |
1053 | unsigned int index; | |
1054 | ||
1055 | if (size <= 192) { | |
1056 | if (!size) | |
1057 | return ZERO_SIZE_PTR; | |
1058 | ||
1059 | index = size_index[size_index_elem(size)]; | |
1060 | } else { | |
1061 | if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE)) | |
1062 | return NULL; | |
1063 | index = fls(size - 1); | |
1064 | } | |
1065 | ||
1066 | return kmalloc_caches[kmalloc_type(flags)][index]; | |
1067 | } | |
1068 | ||
1069 | /* | |
1070 | * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. | |
1071 | * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is | |
1072 | * kmalloc-67108864. | |
1073 | */ | |
1074 | const struct kmalloc_info_struct kmalloc_info[] __initconst = { | |
1075 | {NULL, 0}, {"kmalloc-96", 96}, | |
1076 | {"kmalloc-192", 192}, {"kmalloc-8", 8}, | |
1077 | {"kmalloc-16", 16}, {"kmalloc-32", 32}, | |
1078 | {"kmalloc-64", 64}, {"kmalloc-128", 128}, | |
1079 | {"kmalloc-256", 256}, {"kmalloc-512", 512}, | |
1080 | {"kmalloc-1k", 1024}, {"kmalloc-2k", 2048}, | |
1081 | {"kmalloc-4k", 4096}, {"kmalloc-8k", 8192}, | |
1082 | {"kmalloc-16k", 16384}, {"kmalloc-32k", 32768}, | |
1083 | {"kmalloc-64k", 65536}, {"kmalloc-128k", 131072}, | |
1084 | {"kmalloc-256k", 262144}, {"kmalloc-512k", 524288}, | |
1085 | {"kmalloc-1M", 1048576}, {"kmalloc-2M", 2097152}, | |
1086 | {"kmalloc-4M", 4194304}, {"kmalloc-8M", 8388608}, | |
1087 | {"kmalloc-16M", 16777216}, {"kmalloc-32M", 33554432}, | |
1088 | {"kmalloc-64M", 67108864} | |
1089 | }; | |
1090 | ||
1091 | /* | |
1092 | * Patch up the size_index table if we have strange large alignment | |
1093 | * requirements for the kmalloc array. This is only the case for | |
1094 | * MIPS it seems. The standard arches will not generate any code here. | |
1095 | * | |
1096 | * Largest permitted alignment is 256 bytes due to the way we | |
1097 | * handle the index determination for the smaller caches. | |
1098 | * | |
1099 | * Make sure that nothing crazy happens if someone starts tinkering | |
1100 | * around with ARCH_KMALLOC_MINALIGN | |
1101 | */ | |
1102 | void __init setup_kmalloc_cache_index_table(void) | |
1103 | { | |
1104 | unsigned int i; | |
1105 | ||
1106 | BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || | |
1107 | (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); | |
1108 | ||
1109 | for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { | |
1110 | unsigned int elem = size_index_elem(i); | |
1111 | ||
1112 | if (elem >= ARRAY_SIZE(size_index)) | |
1113 | break; | |
1114 | size_index[elem] = KMALLOC_SHIFT_LOW; | |
1115 | } | |
1116 | ||
1117 | if (KMALLOC_MIN_SIZE >= 64) { | |
1118 | /* | |
1119 | * The 96 byte size cache is not used if the alignment | |
1120 | * is 64 byte. | |
1121 | */ | |
1122 | for (i = 64 + 8; i <= 96; i += 8) | |
1123 | size_index[size_index_elem(i)] = 7; | |
1124 | ||
1125 | } | |
1126 | ||
1127 | if (KMALLOC_MIN_SIZE >= 128) { | |
1128 | /* | |
1129 | * The 192 byte sized cache is not used if the alignment | |
1130 | * is 128 byte. Redirect kmalloc to use the 256 byte cache | |
1131 | * instead. | |
1132 | */ | |
1133 | for (i = 128 + 8; i <= 192; i += 8) | |
1134 | size_index[size_index_elem(i)] = 8; | |
1135 | } | |
1136 | } | |
1137 | ||
1138 | static const char * | |
1139 | kmalloc_cache_name(const char *prefix, unsigned int size) | |
1140 | { | |
1141 | ||
1142 | static const char units[3] = "\0kM"; | |
1143 | int idx = 0; | |
1144 | ||
1145 | while (size >= 1024 && (size % 1024 == 0)) { | |
1146 | size /= 1024; | |
1147 | idx++; | |
1148 | } | |
1149 | ||
1150 | return kasprintf(GFP_NOWAIT, "%s-%u%c", prefix, size, units[idx]); | |
1151 | } | |
1152 | ||
1153 | static void __init | |
1154 | new_kmalloc_cache(int idx, int type, slab_flags_t flags) | |
1155 | { | |
1156 | const char *name; | |
1157 | ||
1158 | if (type == KMALLOC_RECLAIM) { | |
1159 | flags |= SLAB_RECLAIM_ACCOUNT; | |
1160 | name = kmalloc_cache_name("kmalloc-rcl", | |
1161 | kmalloc_info[idx].size); | |
1162 | BUG_ON(!name); | |
1163 | } else { | |
1164 | name = kmalloc_info[idx].name; | |
1165 | } | |
1166 | ||
1167 | kmalloc_caches[type][idx] = create_kmalloc_cache(name, | |
1168 | kmalloc_info[idx].size, flags, 0, | |
1169 | kmalloc_info[idx].size); | |
1170 | } | |
1171 | ||
1172 | /* | |
1173 | * Create the kmalloc array. Some of the regular kmalloc arrays | |
1174 | * may already have been created because they were needed to | |
1175 | * enable allocations for slab creation. | |
1176 | */ | |
1177 | void __init create_kmalloc_caches(slab_flags_t flags) | |
1178 | { | |
1179 | int i, type; | |
1180 | ||
1181 | for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) { | |
1182 | for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { | |
1183 | if (!kmalloc_caches[type][i]) | |
1184 | new_kmalloc_cache(i, type, flags); | |
1185 | ||
1186 | /* | |
1187 | * Caches that are not of the two-to-the-power-of size. | |
1188 | * These have to be created immediately after the | |
1189 | * earlier power of two caches | |
1190 | */ | |
1191 | if (KMALLOC_MIN_SIZE <= 32 && i == 6 && | |
1192 | !kmalloc_caches[type][1]) | |
1193 | new_kmalloc_cache(1, type, flags); | |
1194 | if (KMALLOC_MIN_SIZE <= 64 && i == 7 && | |
1195 | !kmalloc_caches[type][2]) | |
1196 | new_kmalloc_cache(2, type, flags); | |
1197 | } | |
1198 | } | |
1199 | ||
1200 | /* Kmalloc array is now usable */ | |
1201 | slab_state = UP; | |
1202 | ||
1203 | #ifdef CONFIG_ZONE_DMA | |
1204 | for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { | |
1205 | struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i]; | |
1206 | ||
1207 | if (s) { | |
1208 | unsigned int size = kmalloc_size(i); | |
1209 | const char *n = kmalloc_cache_name("dma-kmalloc", size); | |
1210 | ||
1211 | BUG_ON(!n); | |
1212 | kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache( | |
1213 | n, size, SLAB_CACHE_DMA | flags, 0, 0); | |
1214 | } | |
1215 | } | |
1216 | #endif | |
1217 | } | |
1218 | #endif /* !CONFIG_SLOB */ | |
1219 | ||
1220 | /* | |
1221 | * To avoid unnecessary overhead, we pass through large allocation requests | |
1222 | * directly to the page allocator. We use __GFP_COMP, because we will need to | |
1223 | * know the allocation order to free the pages properly in kfree. | |
1224 | */ | |
1225 | void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) | |
1226 | { | |
1227 | void *ret; | |
1228 | struct page *page; | |
1229 | ||
1230 | flags |= __GFP_COMP; | |
1231 | page = alloc_pages(flags, order); | |
1232 | ret = page ? page_address(page) : NULL; | |
1233 | ret = kasan_kmalloc_large(ret, size, flags); | |
1234 | /* As ret might get tagged, call kmemleak hook after KASAN. */ | |
1235 | kmemleak_alloc(ret, size, 1, flags); | |
1236 | return ret; | |
1237 | } | |
1238 | EXPORT_SYMBOL(kmalloc_order); | |
1239 | ||
1240 | #ifdef CONFIG_TRACING | |
1241 | void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) | |
1242 | { | |
1243 | void *ret = kmalloc_order(size, flags, order); | |
1244 | trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags); | |
1245 | return ret; | |
1246 | } | |
1247 | EXPORT_SYMBOL(kmalloc_order_trace); | |
1248 | #endif | |
1249 | ||
1250 | #ifdef CONFIG_SLAB_FREELIST_RANDOM | |
1251 | /* Randomize a generic freelist */ | |
1252 | static void freelist_randomize(struct rnd_state *state, unsigned int *list, | |
1253 | unsigned int count) | |
1254 | { | |
1255 | unsigned int rand; | |
1256 | unsigned int i; | |
1257 | ||
1258 | for (i = 0; i < count; i++) | |
1259 | list[i] = i; | |
1260 | ||
1261 | /* Fisher-Yates shuffle */ | |
1262 | for (i = count - 1; i > 0; i--) { | |
1263 | rand = prandom_u32_state(state); | |
1264 | rand %= (i + 1); | |
1265 | swap(list[i], list[rand]); | |
1266 | } | |
1267 | } | |
1268 | ||
1269 | /* Create a random sequence per cache */ | |
1270 | int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, | |
1271 | gfp_t gfp) | |
1272 | { | |
1273 | struct rnd_state state; | |
1274 | ||
1275 | if (count < 2 || cachep->random_seq) | |
1276 | return 0; | |
1277 | ||
1278 | cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp); | |
1279 | if (!cachep->random_seq) | |
1280 | return -ENOMEM; | |
1281 | ||
1282 | /* Get best entropy at this stage of boot */ | |
1283 | prandom_seed_state(&state, get_random_long()); | |
1284 | ||
1285 | freelist_randomize(&state, cachep->random_seq, count); | |
1286 | return 0; | |
1287 | } | |
1288 | ||
1289 | /* Destroy the per-cache random freelist sequence */ | |
1290 | void cache_random_seq_destroy(struct kmem_cache *cachep) | |
1291 | { | |
1292 | kfree(cachep->random_seq); | |
1293 | cachep->random_seq = NULL; | |
1294 | } | |
1295 | #endif /* CONFIG_SLAB_FREELIST_RANDOM */ | |
1296 | ||
1297 | #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) | |
1298 | #ifdef CONFIG_SLAB | |
1299 | #define SLABINFO_RIGHTS (0600) | |
1300 | #else | |
1301 | #define SLABINFO_RIGHTS (0400) | |
1302 | #endif | |
1303 | ||
1304 | static void print_slabinfo_header(struct seq_file *m) | |
1305 | { | |
1306 | /* | |
1307 | * Output format version, so at least we can change it | |
1308 | * without _too_ many complaints. | |
1309 | */ | |
1310 | #ifdef CONFIG_DEBUG_SLAB | |
1311 | seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); | |
1312 | #else | |
1313 | seq_puts(m, "slabinfo - version: 2.1\n"); | |
1314 | #endif | |
1315 | seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>"); | |
1316 | seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); | |
1317 | seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); | |
1318 | #ifdef CONFIG_DEBUG_SLAB | |
1319 | seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); | |
1320 | seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); | |
1321 | #endif | |
1322 | seq_putc(m, '\n'); | |
1323 | } | |
1324 | ||
1325 | void *slab_start(struct seq_file *m, loff_t *pos) | |
1326 | { | |
1327 | mutex_lock(&slab_mutex); | |
1328 | return seq_list_start(&slab_root_caches, *pos); | |
1329 | } | |
1330 | ||
1331 | void *slab_next(struct seq_file *m, void *p, loff_t *pos) | |
1332 | { | |
1333 | return seq_list_next(p, &slab_root_caches, pos); | |
1334 | } | |
1335 | ||
1336 | void slab_stop(struct seq_file *m, void *p) | |
1337 | { | |
1338 | mutex_unlock(&slab_mutex); | |
1339 | } | |
1340 | ||
1341 | static void | |
1342 | memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) | |
1343 | { | |
1344 | struct kmem_cache *c; | |
1345 | struct slabinfo sinfo; | |
1346 | ||
1347 | if (!is_root_cache(s)) | |
1348 | return; | |
1349 | ||
1350 | for_each_memcg_cache(c, s) { | |
1351 | memset(&sinfo, 0, sizeof(sinfo)); | |
1352 | get_slabinfo(c, &sinfo); | |
1353 | ||
1354 | info->active_slabs += sinfo.active_slabs; | |
1355 | info->num_slabs += sinfo.num_slabs; | |
1356 | info->shared_avail += sinfo.shared_avail; | |
1357 | info->active_objs += sinfo.active_objs; | |
1358 | info->num_objs += sinfo.num_objs; | |
1359 | } | |
1360 | } | |
1361 | ||
1362 | static void cache_show(struct kmem_cache *s, struct seq_file *m) | |
1363 | { | |
1364 | struct slabinfo sinfo; | |
1365 | ||
1366 | memset(&sinfo, 0, sizeof(sinfo)); | |
1367 | get_slabinfo(s, &sinfo); | |
1368 | ||
1369 | memcg_accumulate_slabinfo(s, &sinfo); | |
1370 | ||
1371 | seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", | |
1372 | cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size, | |
1373 | sinfo.objects_per_slab, (1 << sinfo.cache_order)); | |
1374 | ||
1375 | seq_printf(m, " : tunables %4u %4u %4u", | |
1376 | sinfo.limit, sinfo.batchcount, sinfo.shared); | |
1377 | seq_printf(m, " : slabdata %6lu %6lu %6lu", | |
1378 | sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); | |
1379 | slabinfo_show_stats(m, s); | |
1380 | seq_putc(m, '\n'); | |
1381 | } | |
1382 | ||
1383 | static int slab_show(struct seq_file *m, void *p) | |
1384 | { | |
1385 | struct kmem_cache *s = list_entry(p, struct kmem_cache, root_caches_node); | |
1386 | ||
1387 | if (p == slab_root_caches.next) | |
1388 | print_slabinfo_header(m); | |
1389 | cache_show(s, m); | |
1390 | return 0; | |
1391 | } | |
1392 | ||
1393 | void dump_unreclaimable_slab(void) | |
1394 | { | |
1395 | struct kmem_cache *s, *s2; | |
1396 | struct slabinfo sinfo; | |
1397 | ||
1398 | /* | |
1399 | * Here acquiring slab_mutex is risky since we don't prefer to get | |
1400 | * sleep in oom path. But, without mutex hold, it may introduce a | |
1401 | * risk of crash. | |
1402 | * Use mutex_trylock to protect the list traverse, dump nothing | |
1403 | * without acquiring the mutex. | |
1404 | */ | |
1405 | if (!mutex_trylock(&slab_mutex)) { | |
1406 | pr_warn("excessive unreclaimable slab but cannot dump stats\n"); | |
1407 | return; | |
1408 | } | |
1409 | ||
1410 | pr_info("Unreclaimable slab info:\n"); | |
1411 | pr_info("Name Used Total\n"); | |
1412 | ||
1413 | list_for_each_entry_safe(s, s2, &slab_caches, list) { | |
1414 | if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT)) | |
1415 | continue; | |
1416 | ||
1417 | get_slabinfo(s, &sinfo); | |
1418 | ||
1419 | if (sinfo.num_objs > 0) | |
1420 | pr_info("%-17s %10luKB %10luKB\n", cache_name(s), | |
1421 | (sinfo.active_objs * s->size) / 1024, | |
1422 | (sinfo.num_objs * s->size) / 1024); | |
1423 | } | |
1424 | mutex_unlock(&slab_mutex); | |
1425 | } | |
1426 | ||
1427 | #if defined(CONFIG_MEMCG) | |
1428 | void *memcg_slab_start(struct seq_file *m, loff_t *pos) | |
1429 | { | |
1430 | struct mem_cgroup *memcg = mem_cgroup_from_seq(m); | |
1431 | ||
1432 | mutex_lock(&slab_mutex); | |
1433 | return seq_list_start(&memcg->kmem_caches, *pos); | |
1434 | } | |
1435 | ||
1436 | void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos) | |
1437 | { | |
1438 | struct mem_cgroup *memcg = mem_cgroup_from_seq(m); | |
1439 | ||
1440 | return seq_list_next(p, &memcg->kmem_caches, pos); | |
1441 | } | |
1442 | ||
1443 | void memcg_slab_stop(struct seq_file *m, void *p) | |
1444 | { | |
1445 | mutex_unlock(&slab_mutex); | |
1446 | } | |
1447 | ||
1448 | int memcg_slab_show(struct seq_file *m, void *p) | |
1449 | { | |
1450 | struct kmem_cache *s = list_entry(p, struct kmem_cache, | |
1451 | memcg_params.kmem_caches_node); | |
1452 | struct mem_cgroup *memcg = mem_cgroup_from_seq(m); | |
1453 | ||
1454 | if (p == memcg->kmem_caches.next) | |
1455 | print_slabinfo_header(m); | |
1456 | cache_show(s, m); | |
1457 | return 0; | |
1458 | } | |
1459 | #endif | |
1460 | ||
1461 | /* | |
1462 | * slabinfo_op - iterator that generates /proc/slabinfo | |
1463 | * | |
1464 | * Output layout: | |
1465 | * cache-name | |
1466 | * num-active-objs | |
1467 | * total-objs | |
1468 | * object size | |
1469 | * num-active-slabs | |
1470 | * total-slabs | |
1471 | * num-pages-per-slab | |
1472 | * + further values on SMP and with statistics enabled | |
1473 | */ | |
1474 | static const struct seq_operations slabinfo_op = { | |
1475 | .start = slab_start, | |
1476 | .next = slab_next, | |
1477 | .stop = slab_stop, | |
1478 | .show = slab_show, | |
1479 | }; | |
1480 | ||
1481 | static int slabinfo_open(struct inode *inode, struct file *file) | |
1482 | { | |
1483 | return seq_open(file, &slabinfo_op); | |
1484 | } | |
1485 | ||
1486 | static const struct file_operations proc_slabinfo_operations = { | |
1487 | .open = slabinfo_open, | |
1488 | .read = seq_read, | |
1489 | .write = slabinfo_write, | |
1490 | .llseek = seq_lseek, | |
1491 | .release = seq_release, | |
1492 | }; | |
1493 | ||
1494 | static int __init slab_proc_init(void) | |
1495 | { | |
1496 | proc_create("slabinfo", SLABINFO_RIGHTS, NULL, | |
1497 | &proc_slabinfo_operations); | |
1498 | return 0; | |
1499 | } | |
1500 | module_init(slab_proc_init); | |
1501 | #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */ | |
1502 | ||
1503 | static __always_inline void *__do_krealloc(const void *p, size_t new_size, | |
1504 | gfp_t flags) | |
1505 | { | |
1506 | void *ret; | |
1507 | size_t ks = 0; | |
1508 | ||
1509 | if (p) | |
1510 | ks = ksize(p); | |
1511 | ||
1512 | if (ks >= new_size) { | |
1513 | p = kasan_krealloc((void *)p, new_size, flags); | |
1514 | return (void *)p; | |
1515 | } | |
1516 | ||
1517 | ret = kmalloc_track_caller(new_size, flags); | |
1518 | if (ret && p) | |
1519 | memcpy(ret, p, ks); | |
1520 | ||
1521 | return ret; | |
1522 | } | |
1523 | ||
1524 | /** | |
1525 | * __krealloc - like krealloc() but don't free @p. | |
1526 | * @p: object to reallocate memory for. | |
1527 | * @new_size: how many bytes of memory are required. | |
1528 | * @flags: the type of memory to allocate. | |
1529 | * | |
1530 | * This function is like krealloc() except it never frees the originally | |
1531 | * allocated buffer. Use this if you don't want to free the buffer immediately | |
1532 | * like, for example, with RCU. | |
1533 | * | |
1534 | * Return: pointer to the allocated memory or %NULL in case of error | |
1535 | */ | |
1536 | void *__krealloc(const void *p, size_t new_size, gfp_t flags) | |
1537 | { | |
1538 | if (unlikely(!new_size)) | |
1539 | return ZERO_SIZE_PTR; | |
1540 | ||
1541 | return __do_krealloc(p, new_size, flags); | |
1542 | ||
1543 | } | |
1544 | EXPORT_SYMBOL(__krealloc); | |
1545 | ||
1546 | /** | |
1547 | * krealloc - reallocate memory. The contents will remain unchanged. | |
1548 | * @p: object to reallocate memory for. | |
1549 | * @new_size: how many bytes of memory are required. | |
1550 | * @flags: the type of memory to allocate. | |
1551 | * | |
1552 | * The contents of the object pointed to are preserved up to the | |
1553 | * lesser of the new and old sizes. If @p is %NULL, krealloc() | |
1554 | * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a | |
1555 | * %NULL pointer, the object pointed to is freed. | |
1556 | * | |
1557 | * Return: pointer to the allocated memory or %NULL in case of error | |
1558 | */ | |
1559 | void *krealloc(const void *p, size_t new_size, gfp_t flags) | |
1560 | { | |
1561 | void *ret; | |
1562 | ||
1563 | if (unlikely(!new_size)) { | |
1564 | kfree(p); | |
1565 | return ZERO_SIZE_PTR; | |
1566 | } | |
1567 | ||
1568 | ret = __do_krealloc(p, new_size, flags); | |
1569 | if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret)) | |
1570 | kfree(p); | |
1571 | ||
1572 | return ret; | |
1573 | } | |
1574 | EXPORT_SYMBOL(krealloc); | |
1575 | ||
1576 | /** | |
1577 | * kzfree - like kfree but zero memory | |
1578 | * @p: object to free memory of | |
1579 | * | |
1580 | * The memory of the object @p points to is zeroed before freed. | |
1581 | * If @p is %NULL, kzfree() does nothing. | |
1582 | * | |
1583 | * Note: this function zeroes the whole allocated buffer which can be a good | |
1584 | * deal bigger than the requested buffer size passed to kmalloc(). So be | |
1585 | * careful when using this function in performance sensitive code. | |
1586 | */ | |
1587 | void kzfree(const void *p) | |
1588 | { | |
1589 | size_t ks; | |
1590 | void *mem = (void *)p; | |
1591 | ||
1592 | if (unlikely(ZERO_OR_NULL_PTR(mem))) | |
1593 | return; | |
1594 | ks = ksize(mem); | |
1595 | memset(mem, 0, ks); | |
1596 | kfree(mem); | |
1597 | } | |
1598 | EXPORT_SYMBOL(kzfree); | |
1599 | ||
1600 | /* Tracepoints definitions. */ | |
1601 | EXPORT_TRACEPOINT_SYMBOL(kmalloc); | |
1602 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); | |
1603 | EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); | |
1604 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); | |
1605 | EXPORT_TRACEPOINT_SYMBOL(kfree); | |
1606 | EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); | |
1607 | ||
1608 | int should_failslab(struct kmem_cache *s, gfp_t gfpflags) | |
1609 | { | |
1610 | if (__should_failslab(s, gfpflags)) | |
1611 | return -ENOMEM; | |
1612 | return 0; | |
1613 | } | |
1614 | ALLOW_ERROR_INJECTION(should_failslab, ERRNO); |