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_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 (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); |
1615 | |